EPA’s 

Draft Report on the Environment

Technical Document

United States Environmental Protection Agency

Office of Research and Development and the

Office of Environmental Information

Washington, DC 20460

www.epa.gov/indicators/

EPA 600-R-03-050

June 2003

Recycled/Recyclable

Printed with vegetable oil-based ink on 100%

processed chlorine free recycled paper
Disclaimer

This document is an external draft for review purposes only and does not constitute Agency policy. Mention of trade names or

commercial products does not constitute endorsement or recommendation for use.
This report is dedicated to the memory of our friend and colleague, Dr. Felicity (Kim) Devonald. Kim

was a tireless advocate for the development and use of environmental indicators at EPA, pioneering

our efforts to provide useful and reliable descriptions of environmental status and trends. 

Kim joined EPA in1984. Since the early 1990s, she was instrumental in Agency explorations of the

concept of environmental indicators. Her efforts led to the Agency’s first published proposals of fully

developed environmentally based indicators (from public workshops) in the mid-1990s. She was working on material related to the state of science of these indicators almost to the moment of her death,

and much of that material has been incorporated into this Technical Document. 

Without Kim’s example and her early efforts, this report would be far less than it is.

Technical Document ■ EPA’s Draft Report on the Environment 2003

Table of Contents i

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v

List of Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi

Chapter 1: Cleaner Air

1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3

1.1 Outdoor Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-6

1.1.1 What is the quality of outdoor air in the United States? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7

1.1.2 What contributes to outdoor air pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-18

1.1.3 What human health effects are associated with outdoor air pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-23

1.1.4 What ecological effects are associated with outdoor air pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-24

1.2 Acid Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-25

1.2.1 What are the deposition rates of pollutants that cause acid rain? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-25

1.2.2 What are the emissions of pollutants that form acid rain? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-28

1.2.3 What ecological effects are associated with acid deposition? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-29

1.3 Indoor Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-29

1.3.1 What is the quality of the air in buildings in the United States? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-29

1.3.2 What contributes to indoor air pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-31

1.3.3 What human health effects are associated with indoor air pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-31

1.4 Stratospheric Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-32

1.4.1 What are the trends in the Earth’s ozone layer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-32

1.4.2 What is causing changes to the ozone layer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-34

1.4.3 What human health effects are associated with stratospheric ozone depletion? . . . . . . . . . . . . . . . . . . . . . .1-37

1.4.4 What ecological effects are associated with stratospheric ozone depletion? . . . . . . . . . . . . . . . . . . . . . . . . .1-38

1.5 Climate Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-38

1.6 Challenges and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-39 

Chapter 2: Purer Water

2.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3

2.1 Extent and Use of Water Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6

2.2 Waters and Watersheds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.2.1 What is the condition of fresh surface waters and watersheds in the U.S.? . . . . . . . . . . . . . . . . . . . . . . . . . . .2-8

2.2.2 What are the extent and condition of wetlands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-13

2.2.3 What is the condition of coastal waters? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-18

2.2.4 What are pressures to water quality? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-24

2.2.5 What ecological effects are associated with impaired waters? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-49

2.3 Drinking Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-50

2.3.1 What is the quality of drinking water? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-50

2.3.2 What are sources of drinking water contamination? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-52

2.3.3 What human health effects are associated with drinking contaminated water? . . . . . . . . . . . . . . . . . . . . . . .2-52
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2.4 Recreation in and on the Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-53

2.4.1 What is the condition of waters supporting recreational use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-53

2.4.2 What are sources of recreational water pollution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-54

2.4.3 What human health effects are associated with recreation in contaminated waters? . . . . . . . . . . . . . . . . . .2-54

2.5 Consumption of Fish and Shellfish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-56

2.5.1 What is the condition of waters that support consumption of fish and shellfish? . . . . . . . . . . . . . . . . . . . . .2-56

2.5.2 What are contaminants in fish and shellfish, and where do they originate? . . . . . . . . . . . . . . . . . . . . . . . . . .2-62

2.5.3 What human health effects are associated with consuming contaminated fish and shellfish? . . . . . . . . . . .2-62

2.6 Challenges and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-63

Chapter 3: Better Protected Land

3.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

3.1 Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

3.1.1 What is the extent of developed lands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

3.1.2 What is the extent of farmlands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12

3.1.3 What is the extent of grasslands and shrublands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-17

3.1.4 What is the extent of forest lands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-19

3.1.5 What human health effects are associated with land use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

3.1.6 What ecological effects are associated with land use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21

3.2 Chemicals in the Landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-24

3.2.1 How much and what types of toxic substances are released into the environment? . . . . . . . . . . . . . . . . . .3-24

3.2.2 What is the volume, distribution, and extent of pesticide use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27

3.2.3 What is the volume, distribution, and extent of fertilizer use? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-29

3.2.4 What is the potential disposition of chemicals from land? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-30

3.2.5 What human health effects are associated with pesticides, fertilizers, and toxic substances? . . . . . . . . . . .3-37

3.2.6 What ecological effects are associated with pesticides, fertilizers, and toxic substances? . . . . . . . . . . . . . .3-38

3.3 Waste and Contaminated Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-39

3.3.1 How much and what types of waste are generated and managed? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-40

3.3.2 What is the extent of land used for waste management? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-45

3.3.3 What is the extent of contaminated lands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-47

3.3.4 What human health effects are associated with waste management and contaminated lands? . . . . . . . . .3-50

3.3.5 What ecological effects are associated with waste management and contaminated lands? . . . . . . . . . . . .3-51

3.4 Challenges and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-52

Chapter 4: Human Health

4.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3

4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes . . . . . . . . . . . . . . . . . . . .4-7 

4.2 Health Status of the U.S. Compared to the Rest of the World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-11

4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-17

4.3.1 What are the trends for life expectancy? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-18

4.3.2 What are the trends for cancer, cardiovascular disease, chronic obstructive pulmonary disease, and asthma?4-19

4.3.3 What are the trends for gastrointestinal illness? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-25

4.3.4 What are the trends for children’s environmental health issues? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-31

4.3.5 What are the trends for emerging health effects? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-38
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4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-42

4.4.1 Biomonitoring indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-42

4.4.2 Data sources for biomonitoring indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-43

4.4.3 What is the level of exposure to heavy metals? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-44

4.4.4 What is the level of exposure to cotinine? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-50

4.4.5 What is the level of exposure to volatile organic compounds? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-51

4.4.6 What is the level of exposure to pesticides? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-51

4.4.7 What is the level of exposure to persistent organic pollutants? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-53

4.4.8 What are the trends in exposure to environmental pollutants for children? . . . . . . . . . . . . . . . . . . . . . . . . . .4-55

4.4.9 Pollutants for which biomonitoring data are not available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-57

4.4.10 Endocrine disruptors–an emerging issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-59

4.5 Assessing the Environmental Burden of Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-60

4.6 Challenges and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-62

Chapter 5: Ecological Condition

5.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3

5.1 Links Between Stressors and Ecological Outcome: A Framework for Measuring Ecological Condition . . . . . .5-7

5.2 What is the Ecological Condition of Forests? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-9

5.3 What is the Ecological Condition of Farmlands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-25

5.4 What is the Ecological Condition of Grasslands and Shrublands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-32

5.5 What is the Ecological Condition of Urban and Suburban Areas? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-37

5.6 What is the Ecological Condition of Fresh Waters? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-41

5.7 What is the Ecological Condition of Coasts and Oceans? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-53

5.8 What is the Ecological Condition of the Entire Nation? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-64

5.9 Challenges and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-74

APPENDIX A: Databases and Reports Supporting Major Clusters of Indicators Used in the Report with Links for

Additional Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

APPENDIX B: Indicator Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1

APPENDIX C: Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-1

APPENDIX D: Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1

APPENDIX E: References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E-1

APPENDIX F: Background and Chronology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F-1

APPENDIX G: Indicator Quality Review Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G-1

APPENDIX H: EPA Draft Report on the Environment Expert Review Workshop Evaluation Form . . . . . . . . . . . . .H-1

APPENDIX I: Summary Tables of Questions and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I-1
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Preface v

From EPA’s Science Advisor and 

Chief Information Officer

The Environmental Protection Agency (EPA) has been a world

leader in developing and implementing solutions to the environmental problems in our air, water and land. Through the years,

working together with other Federal Agencies we have built a

significant body of science and knowledge that has influenced

national and international public policy, and has raised our

awareness of the value of our environment. Yet, even with the

enormous wealth of understanding and information that we

have today, there are still gaps in our ability adequately monitor

many key indicators in the cascades of events that link our

efforts to protect the environment to the ultimate outcomes we

seek: cleaner air, purer water, better protected land, and better

human health or and ecological condition. To close that gap,

we need both scientifically sound indicators and the national

data to support them.

With the publication of the EPA Draft Report on the

Environment, including this comprehensive Technical Document,

EPA has launched a multi-year effort to improve the state of the

science and our knowledge of the state of the environment.

This effort addresses indicators, monitoring data and models

for better tracking the impacts of our activities on the environment. This document includes indicators that EPA has monitored for many years, including ambient levels of pollutants in

air, water and land. However, we recognize that protecting the

environment ultimately is achieved in terms of human health

and ecological condition, and these two chapters serve as

anchors for the entire report. 

The last sections of each chapter of this report describe challenges and data gaps associated with its particular subject area.

Several general issues have emerged that we will address in the

coming months and years. 

Shifting to an “Outcomes” Framework

Identifying environmental “outcomes” such as better human

health and ecological condition requires a significant shift in

how the Agency frames questions and issues about environmental quality. The first three chapters of this report; Cleaner

Air, Purer Water, and Better Protected Land, ask questions that

tend to follow traditional Agency efforts to prevent, control, or

remediate the effects of pollution. For example:

■ What is the quality of outdoor air in the United States?

■ What are pressures to water quality? 

■ What is the extent of developed land?

The final two chapters on human health and ecological condition, ask questions about outcomes, for example:

■ What are the trends for cancer?

■ What is the ecological condition of coasts and oceans?

To understand how EPA’s mission affects these outcomes, both

directly and indirectly, requires indicators not only of pollutant

releases and ambient conditions, but indicators that span the

chain of events between the release of a pollutant, exposure of

people, plants and animals, and the chain of events from dose

to effects. In the case of human health, factors such as level of

health care, natural disease rates, and actual human exposures

must be factored into an indicator strategy. For ecosystems,

indicators are needed that track hydrology, features of the

landscape, natural disturbances, ecological processes, and

other factors that interact with pollutants to ultimately

determine ecosystem condition.

Availability of Indicators

For a few of the questions in the report, indicators were

identified that are available at the national level. More

frequently, however, we found that promising indicators have

been developed and measured for limited geographic areas, or

for a part of the causal chain. Further exploration of the

relationship between measurements used for assessments and

measurements used for diagnosis of causal factors also is

needed. Development and testing of national indicators has

been a high research priority for EPA’s Office of Research and

Development.

Preface
EPA’s Draft Report on the Environment 2003 ■ Technical Document

vi Preface

Availability of Data

For each of the indicators, we attempted to gather data of

sufficient quality and coverage to support national reporting,

both within and outside the Agency. Generally, the available

data were too limited in place and time to describe national

trends, or even to provide a national snapshot of conditions.

Because the data from different organizations often serve a

broad range of purposes, even when data are available

nationally, gaps remain in the spatial, temporal and

phemonenological coverage needed to track the outcomes 

of many of EPA’s programs. Monitoring networks 

established to address specific issues must be better

integrated through common definitions, designs, methods,

and information systems.

Collaborating for the Future

With this draft as a starting point, we look forward to

collaborating with federal and state agencies to promote

integrated and coherent approaches and mechanisms for

reporting on the state of the environment. Following the release

of this report, we will be working closely with scientists from

other federal and state agencies and the academic community

to explore how best to improve our ability to measure and

assess environmental conditions. 

We invite all of our stakeholders to lend their creativity and

commitment in the months and years ahead as they join us in

meeting Administrator Whitman’s challenge to focus our

resources on the areas of greatest concern and to manage our

work to achieve measurable results. 

___________________________________________________________

Paul Gilman, Ph.D.

Science Advisor and Assistant Administrator for Research and

Development

__________________________________________________________

Kimberly T. Nelson

Chief Information Officer and Assistant Administrator for

Environmental Information
Technical Document Q EPA’s Draft Report on the Environment 2003

Participants vii

Participants

EPA’s Science Advisor sincerely acknowledges the help and advice of all the individuals who assisted in developing the Report on the

Environment Technical Document (TD) 2003 and the Report on the Environment (ROE) 2003. In particular, the following individuals provided critical support:

ROE Technical Document Leads

Peter Preuss - ORD

Denice Shaw - ORD

Vivian Turner - ORD

ROE Leads

Michael Flynn - OEI 

Heather Case - OEI 

Reggie Cheatham - OEI

EPA Contributors

Susan Absher - OECA

Suzanne Annand - OEI

Tom Armitage - OW

Deveraux Barnes - OSWER

Thomas Barnwell (ORD) - Land TD Lead 

David Bayliss - ORD

Joseph Bergstein - Region 2

Eric Burman - OSWER

Paul Bertram - Region 5

Jeff Bigler - OW

Patricia Bradley - ORD

Barry Burgan - OW

Rebecca Calderon (ORD) - Human Health TD Co-Lead

Arden Calvert - OCFO

Pat Childers - OAR

Ed Chu - OA

Paul Cocca - OW

Mark Corbin - OPPTS

Elizabeth Corr - OW

Larry Cupitt - ORD

Denise Cunningham - ORD

Ilan Davidovici - OAR

Wayne Davis - OEI

Kathleen Deener - ORD 

Tom DeMoss - Region 3

Fred Dimmick - OAR

Ron Evans - OAR

Elissa Feldman - OAR

Elaine Francis - ORD

Herman Gibb - ORD

Chris Gillis - OPPTS

Eric Ginsburg - OAR

John Girman - OAR

Anne Grambsch - ORD

Dave Guinnup - OAR

Richard Haeuber - OAR

Michael Hadrick (OAR) - Air TD Lead

Christine Hartless - OPPTS

Tom Helms - OAR

James Hemby - OAR

Brian Hill - ORD

Michelle Hiller - OCIR

Melanie Hoff-OSWER

Rick Hoffman - OW

Karen Hogan - ORD

Joe Hogue - OPPTS

David Hockey - OSWER

Scott Ireland - OW

Elizabeth Jackson - (OEI) ROE Water Lead

Steve Jarboe - OPPTS

Taylor Jarnigan- ORD

Jennifer Jinot - ORD

Bruce Jones - ORD

Marjorie Jones (OW) - Water TD Lead

Catherine Joseph - OPPTS

D’nise Kaalund - OEI

Karen Keller - OSWER

William Kepner - ORD 

Aparna Koppikar - ORD

Charles Kovatch - OW

Rashmi Lal - OEI

James Lazorchak - ORD

Jane Leggett - OAR

Fred Leutner - OW

Barbara Levinson - ORD

Rick Linthurst - OEI

Maricruz MaGowan - OSWER

Deborah Mangis - ORD

Karen Martin - OAR

Michael McDonald (ORD) - Ecological Condition TD Co-Lead

Ron McHugh - OPPTS

Dave McKee - OAR

Hugh McKinnon - ORD

Dan Melamed - OSWER

Jay Messer (ORD) - Ecological Condition TD Co-Lead

Jennifer McLain - OW

Margree McRae - ORD 

Lee Mulkey - ORD

Cindy Sonich-Mullen - ORD

Patricia Murphy - ORD
EPA Regional Support

Thomas Davanzo Region-1

Alice Yeh Region-2

John Armstead Region-3

Cory Berish Region-4

Cynthia Curtis Region-5

William Rhea Region-6

Richard Sumpter Region-7

Gerard Bulanowski Region-8

Nora McGee Region-9

Jon Schweiss Region-10

EPA’s Draft Report on the Environment 2003 Q Technical Document

viii Participants

Susan Offerdal - OECA

Tony Olsen - ORD

Jennifer Orme-Zaveleta - ORD

Betty Overton - ORD 

Cynthia Nolt-Helms - ORD

Dale Pahl - ORD

Doris Price - OAR

Steve Paulsen - ORD

Pasky Pascual- ORD

Jim Pendergast - OW

Dan Petersen - ORD

Jeff Peterson - OW

Michael Plastino - OW

Ilana Preuss - OPEI

Bruce Pumphrey - OECA

Ravi Rao - Region 4

Stig Regli - OW

Harvey Richmond - OAR

Mary Ross - OAR

Kevin Rosseel - OAR

William Russo - ORD

Vicki Sandiford - OAR

Keith Sargent- OPEI

Joel Scheraga - ORD

Dina Schreinemachers - ORD

Henry Schuver - OSW

Velu Senthill - OEI

Ronald Shafer - (OEI) ROE Air Lead

Heather Shoven- OPPT

Terry Slonecker - ORD

Ron Slotkin - ORD 

Deborah Smegal - (OEI) ROE Human Health Lead

Jonathan Smith - ORD

Elizabeth Smith - ORD

Chuck Spooner - OW

Susan Stone - OAR

James T. Sullivan - OAR

Kevin Summers - ORD

Carol Terris - OPPTS

Sylvia Thomas - OEI

Tim Torma - OPEI

Amy Vasu - OAR

Doreen Vetter - OW

David Vogler - Region 6

James White - OAR

Jim Wickham - ORD

Mary Wigginton - ORD

Glenn Williams - OPPTS

Darrell Winner - ORD

Louise Wise - OW

Hal Zenick (ORD) - Human Health TD Co-Lead
Technical Document Q EPA’s Draft Report on the Environment 2003

Participants ix

External Experts

Peer Review of Indicators (June 10-12,

2002)

Thomas Burke - The Johns Hopkins University, School of Public

Health; Pew Commission Report

Keith Harrison - Michigan Environmental Science Board

Anthony Janetos - The H. John Heinz III Center for Science,

Economics and the Environment

Patrick Kinney - Mailman School of Public Health/ Div Environ

Health Sciences /Columbia University

James Listorti - formerly The World Bank

Robin O’Malley - The H. John Heinz III Center for Science,

Economics and the Environment

Ed Rankin - Ohio University: formerly Ohio EPA

Phil Singer - University of North Carolina

William Steen - University of Georgia

Roger Tankersley - Tennessee Valley Authority 

Robert VanDolah - Marine Resources Research Institute/ South

Carolina Department of Natural Resources

Bailus Walker - Howard University Hospital

Chris Yoder - Ohio University: formerly Ohio EPA

External Consultation (May 10, 2002)

Thomas Burke - The Johns Hopkins University, School of Public

Health 

John Godleski - Harvard School of Public Health

Anthony Janetos - World Resources Institute; currently with The H.

John Heinz III Center for Science, Economics and the Environment

Daniel Markowitz - Malcolm Pirnie

Robin O’Malley - The H. John Heinz III Center for Science,

Economics and the Environment

Jonathan Patz - The Johns Hopkins University, School of Public

Health

James Pratt - Portland State University

Thomas Sinks - Department of Health and Human Services/Centers

for Disease Control and Prevention

Terry Young - Environmental Defense Fund

NRC Consultation (March 2002)

David Policansky

James Reisa

Members of the Board on Environmental Studies and Toxicology

Environmental Council of States (ECOS)

State Indicators Workgroup

Karen Atkinson - Texas

Steve Brown - ECOS Executive Director

Wendy Caperton - Oklahoma

Christine Epstein - ECOS

Joe Francis - Nebraska

Keith Harrison - Michigan

Linda Haynie - Texas

Roger Kanerva - Illinois

Edwin Levine - Florida

Linda Mazur - California

Linda McCarty - Missouri

Leslie McGeorge - New Jersey

George Meyer - Wisconsin

Tim Mulholland - Wisconsin

Arleen O’Donnell - Massachusetts

Laura Pasquale - Florida

Greg Pettit - Oregon

Eileen Pierce - Wisconsin

Dee Ragsdale - Washington

Jon Sandoval - Idaho

Jacqueline Schafer - Arizona

Barbara Sexton - Pennsylvania

Val Siebal - California

Beth Vaughan - California

Gordon Wegwart - Minnesota

Clinton Whitney - California

Bob Zimmerman - Delaware

Federal Agency Workgroup

Alan Hecht - CEQ Lead

Margot Anderson - Department of Energy

Adela Backiel - Department of Agriculture

Ralph Cantral - National Oceanic and Atmospheric Administration

Mark Delfs - Department of Agriculture

George Dunlop - Department of Defense

Tyler Duvall - Department of Transportation

Bill Effland - Department of Agriculture/Natural Resources

Conservation Service 

Beverly Getzen - Army Corps of Engineers

Jimmy Glotfelty - Department of Energy

James Hanson - Department of the Interior

Theodore Heintz - Department of the Interior

Woody Kessel - Department of Health and Human Services

Linda Lawson - Department of Transportation

Camille Mittleholtz - Department of Transportation

Melinda Moore - Department of Health and Human Services/Centers

for Disease Control and Prevention
EPA’s Draft Report on the Environment 2003 Q Technical Document

x Participants

Contractor Technical Support

Technology Planning and Management

Corporation (TPMC) & Perot Systems

Government Services (PSGS)

Ross and Associates Environmental

Consulting, Ltd.

Science Applications International

Corporation

FTN & Associates, Ltd.

Environmental Management Consulting

Eastern Research Group, Inc.

WESTAT

Independent Consultants and Editors

- Ellen Chu 

- Anne Ruffner Edwards

- Barbara Shapiro

- June Taylor
Technical Document Q EPA’s Draft Report on the Environment 2003

Introduction xi

Introduction

“When I leave office, I want to be able to say that America’s air is cleaner,

its water is purer, and its land better protected than it was when I arrived.

As we seek to achieve this goal, EPA needs to be accountable for our stewardship.”

Christine Todd Whitman, Administrator, U.S. Environmental

Protection Agency

In November 2001, EPA Administrator Christine Todd Whitman

directed the Agency to bring together its national, regional and program office data to produce a report on the “state of the environment.” The report would represent the first step of the

Environmental Indicators Initiative, a multi-year process that would

ultimately allow future EPA administrators to better measure and

report on progress toward environmental and human health goals

and to ensure the Agency’s accountability to the public.

To produce this report, EPA’s Office of Research and Development

(ORD) and Office of Environmental Information (OEI) led a collaborative effort to identify the key questions to be answered by the

report, to identify an initial set of indicators, and to develop a

process for reviewing and selecting the indicators and supporting

data to be included in the final report. This task was accomplished

thanks to the efforts of numerous EPA staff, representatives from

other federal agencies, representatives from the states and tribes,

and external advisors and reviewers. The indicators and supporting

data used in this report were generated by EPA and other federal,

state, tribal, regional, local, and non-governmental organizations. The

Council on Environmental Quality in the Executive Office of the

President was helpful throughout in coordinating interagency contributions to the project. 

EPA’s Draft Report on the Environment (ROE) consists of this Technical

Document and a version of the report for general reading. These

reports pose national questions about the environment and human

health and answer those questions wherever scientifically sound indicators and high-quality supporting data are available. The reports

both pose questions and present indicators related to:

Q Cleaner Air

Q Purer Water

Q Better Protected Land

Q Human Health

Q Ecological Condition 

This Draft Technical Document discusses the limitations of the currently available indicators and data, and the gaps and challenges that

must be overcome to provide better answers in the future. 

For a few indicators, data are available that are truly representative of

the entire nation. For other indicators, data currently are available for

only one region (such as the East Coast or the Northwest), but the

indicator could obviously be applied nationally if the data were available. Based on the availability of supporting data, indicators that

were selected and included in this report were assigned to one of

two categories:

Q Category 1 –The indicator has been peer reviewed and is supported by national level data coverage for more than one time

period. The supporting data are comparable across the nation

and are characterized by sound collection methodologies, data

management systems, and quality assurance procedures.

Q Category 2 –The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multistate regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of

the indicator have been measured (e.g., data has been collected

for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by

sound collection methodologies, data management systems, and

quality assurance procedures.

This report is part of EPA’s continuing effort to identify, improve,

and utilize environmental indicators in its planning, management, and

public reporting. EPA’s specific strategies and performance targets to

protect human health and the environment are presented in the

Agency’s strategic and annual plans. These planning and performance documents, together with the questions, indicators and data

presented in these reports, will allow EPA to better define and measure the status and trends in environment and health, and to better

measure the effectiveness of its programs and activities. 

This technical report is a draft, intended to elicit comments and

suggestions on the approach and findings. To learn more about EPA’s

Draft Report on the Environment and the Environmental Indicators

Initiative, and to provide comments and feedback, please visit

http://www.epa.gov/indicators/.

Chapter 1:

Cleaner Air
Indicators that were selected and included in this chapter were assigned to one of two categories:

■ Category 1 –The indicator has been peer reviewed and is supported by national level data coverage for more than one time period.

The supporting data are comparable across the nation and are characterized by sound collection methodologies, data management

systems, and quality assurance procedures.

■ Category 2 –The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multi-state

regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of the

indicator have been measured (e.g., data has been collected for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by sound collection methodologies, data management systems, and

quality assurance procedures.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.0 Introduction 1-3

1.0 Introduction

In 1970, Congress responded to concern over visible air pollution,

irritating smog, and associated health and ecological effects by

enacting the federal Clean Air Act (CAA). As a result, total national

emissions of the six criteria air pollutants decreased by 25 percent

between 1970 and 2001. Emissions of air toxics have declined as

well, dropping 24 percent between 1990 and 1993 (the baseline

period) and 1996. One of the major components of acid rain, wet

sulfate deposition, has also decreased substantially (EPA, OAQPS,

September 2002).

These improvements occurred during a time of significant growth in

the nation’s population and economy: from 1970 to 2001, the Gross

Domestic Product (GDP) increased by 161 percent, the number of

people increased from about 203 million to more than 280 million,

energy consumption increased by 42 percent, and vehicle miles 

traveled increased by 149 percent (Exhibit 1-1) (EPA, OAQPS,

September 2002). 

Despite progress toward cleaner air, in 2001 more than 133 million

people lived in counties where monitored air quality was unhealthy 

at times because of high levels of at least one criteria air pollutant

(EPA, OAQPS, September 2002). Even after decades of regulation

and emissions control, certain air quality problems persist. In 

particular, ozone and particulate matter are the criteria pollutants

most often found at levels above national health-based standards. 

Outdoor air is not the nation’s only air quality concern. The levels 

of pollutants in the air inside homes, schools, and other buildings

can be higher than in the outdoor air. Uncertainty remains about 

levels of indoor air pollutants, such as radon and environmental

tobacco smoke.

Changes to stratospheric ozone levels are also concerns. The

stratospheric ozone layer has become substantially thinner in recent

decades, although scientists generally believe it will recover over the

next several decades as a result of international controls (Scientific

Assessment Panel, 2003). 

This chapter summarizes the current status and trends in air quality,

the pressures affecting air quality, and information regarding human

health and ecological effects. It poses fundamental questions about

air quality, contributors to pollution, and health and ecological

effects, and it uses indicators drawn from well-reviewed data sources

to help answer those questions. Exhibit 1-2 lists these questions

and indicators, as well as the number of the chapter section where

each indicator is presented.

The chapter is divided into six main sections:

■ Section 1.1 discusses the quality of outdoor air.

■ Section 1.2 provides information about acid deposition.

■ Section 1.3 examines the quality of air inside homes, schools, and

other buildings.

■ Section 1.4 focuses on stratospheric ozone.

■ Section 1.5 briefly addresses climate change research plans.

■ Section 1.6 reviews the challenges and data gaps that remain in

assessing the nation’s air quality.

-50

0

50

100

150

200

Percent of Change from 1970

70 01

161%

149%

42%

39%

-25%

80 90 96 97 98 99 00 95

Energy Consumption

Aggregate Emissions

(Criteria Air Pollutants)

U.S. Population

Vehicle Miles

Traveled

Gross Domestic

Product

Exhibit 1-1: Comparison of growth measures and emission trends, 

1970–2001

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.
1-4 1.0 Introduction Chapter 1 - Cleaner Air

-

-

-

-

-

-

-

Question Indicator Name Category Section

Question Indicator Name Category Section

Deposition: wet sulfate and wet nitrogen

Emissions (utility): sulfur dioxide and nitrogen oxides 

2

2

What ecological effects are associated with 

acid deposition? 

What are the deposition rates of pollutants that cause 

acid rain? 

What are the emissions of pollutants that form acid rain?

Acid Deposition

What is the quality of outdoor air in the United States? 

(See also following four questions)

Number and percentage of days that metropolitan 

statistical areas (MSAs) have Air Quality Index (AQI) values 

greater than 100

2

Number of people living in areas with air quality levels 

above the NAAQS for particulate matter (PM) and ozone

1

Ambient concentrations of particulate matter: PM2.5 and 1 1.1.1.b

PM10

Ambient concentrations of ozone: 8-hour and 1-hour 1 1.1.1.b

Ambient concentrations of lead 1 1.1.1.b

What are the impacts of air pollution on visibility in 

national parks and other protected lands? Visibility 1

What are the concentrations of toxic air pollutants in

ambient air? 

Ambient concentrations of selected air toxics 2

What contributes to outdoor air pollution?

(See also following three questions)

See emissions indicators

Emissions: particulate matter (PM2.5 and PM10) 2 1.1.2.a 

sulfur dioxide, nitrogen oxides, and 

volatile organic compounds

Lead emissions 2 1.1.2.a

What are contributors to toxic air pollutants in 

ambient air?

Air toxics emissions

To what extent is U.S. air quality the result of pollution

from other countries, and to what extent does U.S. air 

pollution affect other countries? 

No Category 1 or 2 indicators identified 

What human health effects are associated with 

outdoor air pollution? 

No Category 1 or 2 indicators identified

Also see Human Health chapter

What ecological effects are associated with outdoor 

air pollution?

No Category 1 or 2 indicators identified 

Also see Ecological Condition chapter

How many people are living in areas with particulate matter 

and ozone levels above the National Ambient Air Quality 

Standards (NAAQS)? 

What are the concentrations of some criteria air 

pollutants: PM2.5, PM10, ozone, and lead? 

What are contributors to particulate matter, 

ozone, and lead in ambient air?

Outdoor Air Quality

Exhibit 1-2: Air – Questions and Indicators

1.1.1.a

1.1.1.c

1.1.1.d

1.1.2

2 1.1.2.b

1.1.2.c

1.1.3

1.1.4

1.2.1

1.2.2

No Category 1 or 2 indicators identified 1.2.3

Also see Ecological Condition chapter

1.1.1

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.0 Introduction 1-5

Question Indicator Name Category

U.S. homes above EPA's radon action levels 2

Percentage of homes where young children are 

exposed to environmental tobacco smoke 2

Section

What contributes to indoor air pollution? No Category 1 or 2 indicators identified 

Also see Human Health chapter 

No Category 1 or 2 indicators identified

Also see Human Health chapter 

What human health effects are associated with 

indoor air pollution? 

Question Indicator Name Category

What are the trends in the Earth's ozone layer? Ozone levels over North America 1

Worldwide and U.S. production of ozone-depleting 

substances (ODSs) 2

Concentrations of ozone-depleting substances (effective 

equivalent chlorine) 2

Section

What human health effects are associated 

with stratospheric ozone depletion? No Category 1 or 2 indicators identified 

What ecological effects are associated with stratospheric 

ozone depletion? 

No Category 1 or 2 indicators identified 

What is the quality of the air in buildings in the United States? 

What is causing changes to the ozone layer? 

Indoor Air Quality

Stratospheric Ozone

1.3.1

1.3.2

1.4.1

1.4.2

1.4.2

1.4.3

1.4.4

1.3.1

1.3.3
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-6 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

1.1 Outdoor Air Quality 

Among the pollutants affecting outdoor air quality are:

■ Criteria pollutants–ozone (O3), particulate matter (PM), 

sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide

(CO), and lead.

■ Air toxics–pollutants such as mercury and benzene. 

Under the Clean Air Act, EPA and states collect data on the six criteria air pollutants to measure compliance with National Ambient Air

Quality Standards (NAAQS) (Exhibit 1-3). “Primary” NAAQS are set

to protect public health with an adequate margin of safety, and “secondary” NAAQS protect against adverse welfare effects (e.g., effects

on vegetation, ecosystems, visibility, manmade materials) (42 U.S.C.

7408 and 7409). After initially adopting NAAQS for each of the criteria air pollutants in the 1970s, EPA has periodically reviewed and

sometimes revised the standards. EPA recently revised the healthbased standard for ozone and added a new standard for fine PM2.5

based on new health studies (EPA, 2003; EPA, 1997).

Criteria air pollutants are monitored through the National Air

Monitoring Stations/State or Local Air Monitoring Stations network.

This network consists of more than 5,000 monitors operating at

3,000 sites across the country, mostly in urban areas (EPA, OAQPS,

September 2002). Measurements are taken on both a daily and 

continuous basis to assess both peak concentrations and overall

trends, and are reported in the Air Quality Subsystem (AQS) 

database. In addition to other uses, EPA analyzes these air quality

measurements to designate areas as either attainment or nonattainment for specific criteria air pollutants (i.e., determines if air quality

levels in an area violate the NAAQS).

While air quality data on criteria air pollutants are ample, national

data on air toxics concentrations are limited. Several metropolitan

areas measure ambient air toxics concentrations, but there are few

standards by which to evaluate levels of concern. In addition, 

cumulative or synergistic impacts of various air pollutants are not

well understood.

Visibility is another outdoor air concern. Some data on this aspect of

air quality are available from the Interagency Monitoring of Protected

Visual Environments (IMPROVE) network, which collects data to

characterize visibility at national parks and other protected areas.

This section addresses the following specific questions about 

outdoor air quality:

■ What is the quality of outdoor air in the United States? (Section

1.1.1)

▲ How many people are living in areas with particulate matter and

ozone levels above the NAAQS?

Exhibit 1-3: National Ambient Air Quality Standards (NAAQS) in effect as of February 2003

9 ppm (10 mg/m3) 

35 ppm (40 mg/m3)

1.5 μg/m3

0.053 ppm (100 μg/m3)

0.12 ppm (235 μg/m3) 

0.08 ppm (157 μg/m3)

50 μg/m3

150 μg/m3

15 μg/m3

65 μg/m3

0.03 ppm (80 μg/m3) 

0.14 ppm (365 μg/m3)

8-hourb

1-hourb

Maximum Quarterly Average

Annual Arithmetic Mean

Maximum Daily 1-hour Averagec

4th Maximum Dailyd 8-hour Average

Annual Arithmetic Mean

24-houre 

Annual Arithmetic Meanf 

24-hourg

Annual Arithmetic Mean 

24-hourb

CO 

Pb

NO2

O3

PM10

PM2.5

SO2

a Parenthetical value is an approximately equivalent concentration. (See 

40 CFR Part 50).

b Not to be exceeded more than once per year.

c The standard is attained when the expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm 

is equal to or less than one, as determined according to Appendix H of 

the Ozone NAAQS.

d Three-year average of the annual 4th highest daily maximum 8-hour concentration.

e The short-term (24-hour) standard of 150 μg/m3 is not to be exceeded more than once per year 

on average over three years.

f Spatially averaged over designated monitors.

g The form is the 98th percentile.

No Secondary Standard 

No Secondary Standard

Same as Primary Standard

Same as Primary Standard

Same as Primary Standard 

Same as Primary Standard

Same as Primary Standard

Same as Primary Standard

Same as Primary Standard

Same as Primary Standard

3-hourb 0.50 ppm (1,300 μg/m3)

Type of Average Standard Level Concentrationa Type of Average Standard Level Concentration

Pollutant Primary Standard (Health Related) Secondary Standard (Welfare Related)

Source: Based on EPA, Office of Air Quality Planning and Standards. National Air Quality and Emissions Trends Report, 1999. March 2001.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-7

▲ What are the concentrations of some criteria air pollutants:

PM2.5, PM10, ozone, and lead?

▲ What are the impacts of air pollution on visibility in national

parks and other protected lands?

▲ What are the concentrations of toxic air pollutants in 

ambient air?

■ What contributes to outdoor air pollution? (Section 1.1.2)

▲ What are contributors to particulate matter, ozone, and lead 

in ambient air?

▲ What are contributors to toxic air pollutants in ambient air?

▲ To what extent is U.S. air quality the result of pollution from

other countries, and to what extent does U.S. air pollution

affect other countries?

■ What human health effects are associated with outdoor air 

pollution? (Section 1.1.3)

■ What ecological effects are associated with outdoor air pollution?

(Section 1.1.4)

1.1.1 What is the quality of

outdoor air in the United States?

The nation’s air quality has generally improved, as indicated by

trends derived by averaging the direct measurements from the

nation’s criteria air pollutant monitoring stations on a yearly basis. In

general, air pollution concentrations are declining, and overall air

quality is improving (EPA, OAQPS, September 2002). 

Most areas of the U.S. now have concentrations of NO2, SO2, CO,

and lead that are below the level of the NAAQS (EPA, OAQPS,

September 2002). However, ozone levels are above the level of the

standard in many heavily populated areas, including many of the

urban areas in the eastern half of the U.S. and in most of the urban

areas in California (EPA, OAQPS, March 2001). Concentrations of

PM2.5—particles less than or equal to 2.5 micrometers in diameter—are above the level of the standard in much of the eastern U.S.

and parts of California (EPA, OAQPS, September 2002).

It is important to recognize that while the national trend is toward

cleaner air, regional and local conditions can vary quite greatly. 

This report focuses on national status and trends, but regional and

local conditions should be evaluated as well, with the goal of understanding regional air quality conditions and trends and improving air

quality in those areas where air quality does not meet the standards. 

A number of indicators, described on the following pages, help 

to answer the questions posed in this section about outdoor 

air quality:

■ Number and percentage of days that Metropolitan Statistical

Areas (MSAs) have Air Quality Index (AQI) values greater 

than 100

■ Number of people living in areas with air quality levels above the

NAAQS for particulate matter and ozone

■ Ambient concentrations of particulate matter: PM2.5 and PM10

■ Ambient concentrations of ozone: 8-hour and 1-hour

■ Ambient concentrations of lead

■ Visibility

■ Ambient concentrations of selected air toxics

■ Emissions of particulate matter (PM2.5 and PM10), sulfur dioxide,

nitrogen oxides, and volatile organic compounds

■ Lead emissions

■ Air toxics emissions

Indicator

Number and percentage of days that metropolitan statistical

areas (MSAs) have Air Quality Index (AQI) values greater 

than 100
Indicator

1-8 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

One measure of outdoor air quality is the daily AQI, which is

based on concentrations of five of the criteria air pollutants:

ozone, PM, CO, SO2, and NO2. The AQI indicates how clean or

polluted the air is and the associated health concerns. It focuses

on the health effects that can occur within a few hours or days

after breathing polluted air. AQI data are compiled by state and

local agencies and must be reported in metropolitan statistical

areas (MSAs) with populations of more than 350,000 (EPA,

OAQPS, March 2001). 

AQI values range from 0 to 500, with higher numbers indicating

more air pollution and more potential risk to public health. An AQI

value of 100 generally corresponds to the short-term public

health standard set by EPA for a particular pollutant. Values below

100 are generally thought of as satisfactory. However, unusually

sensitive individuals may experience health effects when AQI values are between 50 and 100. Values above 100 suggest increasingly unhealthy air; sensitive population groups, such as children,

the elderly, and those with respiratory illnesses, are likely to be

among the first affected as the values increase.

The AQI scale is divided into six categories, each color-coded to

correspond to a different level of health concern. For example, 

■ The color green is associated with “good” air quality or an AQI

from 0 to 50. 

■ Yellow or “moderate”—51 to 100. 

■ Orange or “unhealthy for sensitive groups”—101 to 150.

■ Red or “unhealthy”—151 to 200. 

■ Purple or “very unhealthy”—201 to 300. 

■ Maroon or “hazardous”—301 to 500. AQI

values over 300 would trigger health warnings of emergency conditions for the entire

population (EPA, OAQPS, March 2001). 

The highest AQI value for an individual pollutant becomes the AQI value for that area for

that particular day. For example, if on a day a

certain area had AQI values of 150 for ozone

and 120 for PM, the AQI value would be 150

for the pollutant ozone on that day. However,

for all pollutants above 100, the appropriate

sensitive groups would be cautioned. Ozone

levels most often drive the AQI, but experts

anticipate that PM2.5 will also be a key driver

of the AQI in coming years.

The AQI is useful in communicating to the

public the air quality in a specific area on a

given day and the potential health effects and

actions to avoid exposure and reduce harmful impacts. Nationally,

the number and percentage of days with AQI values of more than

100 gives a sense of the number of days that are potentially

unhealthy for sensitive populations. 

What the Data Show

This indicator is the annual sum of the number of days, and percentage of days, with AQI values above 100 across all MSAs with

a population greater than 500,000. To assess trends, the number

of days is adjusted to reflect changes in air quality standards or

criteria for the number of MSAs reporting.

Between 1988 and 2001, the number of days with an AQI of 100

or greater decreased from approximately 3,300 days to approximately 1,000 days. In 1989 and after, the number of days with an

AQI of 100 or greater ranged between 1,000 and 2,000. Based

on EPA AQI data, the percentage of days across the country with

AQI values above 100 dropped from almost 10 percent in 1988

to 3 percent in 2001 (Exhibit 1-4) (EPA, OAQPS, December

1998; EPA, OAQPS, 2001). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ The data for this indicator are associated with large MSAs only

(500,000 people or more); therefore, the data tend to reflect

urban air quality.

Number and percentage of days that metropolitan statistical areas (MSAs) have Air Quality

Index (AQI) values greater than 100 – Category 2 Number of days with AQI > 100

3500

Number of Days

Percent of Total Days

3000

2500

2000

1500

1000

500

1989 1991 1993

Year

1995 1997 1999 2001

0

Percent of Total Days

24

20

16

12

8

4

0

Exhibit 1-4: Number and percentage of days with Air Quality Index 

(AQI) greater than 100, 1988-2001

Note: Data are for MSAs > 500,000

Source: Data used to create graphic are drawn from EPA, Office of Air Quality Planning and Standards. 

National Air Quality and Emissions Trends Report, 1997. Table A-15. December, 1998; EPA, Office of Air 

Quality Planning and Standards. Air trends: Metropolitan area trends, Table A-17, 2001. (February 25, 

2003; http://www.epa.gov/airtrends/metro.html).

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Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-9

■ This composite AQI indicator does not identify the pollutants

of concern–that is, it does not show which pollutant(s) are

causing the days with an AQI of more than 100, or which 

ones have decreased and are responsible for an improvement 

in the AQI.

■ This composite AQI indicator does not show which areas, or

how many areas, have problems–a specific number of days

could reflect a few areas with persistent problems or many

areas with occasional problems.

Data Source

The data sources for this indicator were “Air Trends: Metropolitan

area trends,” Table A-17, EPA, 2001, and National Air Quality and

Emissions Trends Report, 1997, Table A-15, EPA, 1998. (See

Appendix B, page B-2, for more information.) 

Indicator Number and percentage of days that metropolitan statistical areas (MSAs) have Air Quality

Index (AQI) values greater than 100 – Category 2 (continued)

1.1.1.a How many people are

living in areas with particulate

matter and ozone levels above the

National Ambient Air Quality

Standards (NAAQS)?

In 2001, more than 133 million Americans (of a total population 

of 281 million) lived in counties where monitored outdoor air quality

was unhealthy at times because of high levels (levels above the

NAAQS) of at least one criteria air pollutant (EPA, OAQPS,

September 2002). Ozone and PM remain the most persistent 

criteria pollutants.

Indicator

Number of people living in areas with air quality levels above

the NAAQS for particulate matter (PM) and ozone

The number of people living in areas above the level of the healthbased NAAQS gives some indication of the number of people

potentially exposed to unhealthy air.

What the Data Show

Despite trends of decreasing concentrations of criteria pollutants,

many people still live in areas with air quality levels above the

health-based standards for ozone and PM. In 2001, 11.1 million

people lived in counties with air quality concentrations that at

times were above the NAAQS for PM10, and 72.7 million people

lived in counties with air quality concentrations above the standard for PM2.5. Some 40.2 million people lived in counties with

concentrations that at times were above the 1-hour ozone standard, and 110.3 million people lived in counties with concentrations above the 8-hour ozone standard (Exhibit 1-5) (EPA,

OAQPS, September 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ The indicator helps in understanding the number of people

potentially affected by air quality problems, but it does not tell

the actual number of people exposed to unhealthy air. Not all

counties have complete monitoring data, so some areas may be

excluded. However, the areas of most concern are likely covered. 

Indicator Number of people living in areas with air quality levels above the NAAQS for 

particulate matter (PM) and ozone – Category 1
Indicator

1-10 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

■ The indicator does not tell the amount or extent to which different areas exceed the standards, and so does not provide any

specific exposure data.

Data Sources

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-3, for more information.) 

Number of people living in areas with air quality levels above the NAAQS for 

particulate matter (PM) and ozone – Category 1 (continued)

Exhibit 1-5: People living in areas with air quality 

above the National Ambient Air Quality Standards 

(NAAQS) in 2001

0 50 100 150

Sulfur Dioxide

Particulate 

Matter (<10μm)

Particulate 

Matter (<2.5μm)

Carbon 

Monoxide

Lead

Any 

NAAQS

Ozone

Nitrogen 

Dioxide

Millions of People

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002. Pollutants

110.3 

(8-hour)

0.007

11.1

72.7

0.7

2.7

133.1

40.2 (1-hour)

0

1.1.1.b What are the

concentrations of some criteria air

pollutants: PM2.5, PM10, ozone,

and lead?

Three indicators, presented on the following pages, are available to

help answer this question: ambient concentrations of particulate

matter, ambient concentrations of ozone (8-hour and 1-hour), and

ambient concentrations of lead. Concentrations of the criteria air

pollutants have decreased over the past 2 decades, with substantial

reductions in SO2, CO, and lead levels (Exhibit 1-6) (EPA, OAQPS,

September 2002). However, PM2.5 and ozone concentrations are

above the NAAQS in many areas, potentially exposing a significant

percentage of the U.S. population to unhealthy air (EPA, OAQPS,

September 2002). 

The data for national levels of criteria pollutants tell only part of the

story. Although significant improvements have been occurring

nationally and regionally, some areas still have chronic air quality

problems. The Northeast, for example, experiences frequent and

widespread violations of the ozone health-based standard

(Northeast States for Coordinated Air Use Management, 2002).

Indicators

Ambient concentrations of particulate matter: PM2.5 and PM10

Ambient concentrations of ozone: 8-hour and 1-hour

Ambient concentrations of lead

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Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-11

Particulate matter concentrations are a good indication of air

quality health effects, because of concerns about associated 

respiratory effects. This indicator is based on the annual average

concentrations, in micrograms per cubic meter (μg/m3) of PM2.5

and PM10. PM10 refers to particles 10 micrometers or less in 

diameter, and PM2.5 refers to particles less than or equal to 2.5

micrometers in diameter.

Trends in PM10 are presented from 1992 to 2001, and comparable PM2.5 data have been collected since 1999 (EPA, OAQPS,

September 2002). 

What the Data Show

Concentrations of PM10 decreased by 14 percent between 1992

and 2001 (Exhibit 1-7), and are below the NAAQS standard 

concentration in most areas. Concentrations of PM2.5 are above

the level of the annual standard in much of the eastern U.S. and

parts of California (Exhibit 1-8) (EPA, OAQPS, September 2002).

Annual average PM2.5 concentrations are generally higher in the

eastern U.S. than in the West, mostly because sulfate concentrations are four to five times higher in the eastern U.S. (largely due

to coal-fired power plants) (EPA, OAQPS, September 2001).

Indicator Ambient concentrations of particulate matter: PM2.5 and PM10– Category 1

90% of sites have concentrations below this line

0

10

20

30

40

50

60

92 93 94 95 96 97 98 99 00 01

Concentration, μ g/m3

Average

1992–01: 14% decrease

NAAQS

Exhibit 1-7: Particulate matter (PM10)air quality, 

1992–2001

based on seasonally weighted annual average

10% of sites have concentrations below this line

Coverage: 770 monitoring sites nationwide with sufficient data to assess trends.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

Exhibit 1-6: Percent reduction in concentration of six criteria air pollutants 

regulated under the Clean Air Act, 1982-2001

Percent Change in Air Concentration

Note: Trend data for PM2.5 are not available. Trend data for PM10 are only available for 1992-2001. Between 1992-2001, ozone (8-hour) concentrations remained level.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National Air Quality: 2001 Status and Trends. September 2002.

0%

-20%

-40%

-60%

-80%

-100%

Particulate 

Matter

(PM10)

Ozone

(1-hour)

Ozone

(8-hour)

Sulfur

Dioxide

Nitrogen

Dioxide

Carbon 

Monoxide

Lead

1992-2001

1982-2001
Indicator

1-12 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

Ambient concentrations of particulate matter: PM2.5 and PM10– Category 1 (continued)

Micrograms per Cubic Meter (μg/m3) 

> 20

15 - 20

12 - 15

< 12

Do not meet minimum data completeness.

Minimum 11 samples per calendar quarter required.

Data unavailable.

PM2.5 Standard (annual arithmetic mean) is 15 μg/m3

Exhibit 1-8: 2001 annual average particulate matter (PM2.5) concentrations

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National Air Quality: 2001 Status and Trends. September 2002.

Indicator Gaps and Limitations

Limitations of this indicator include the following (EPA, OAQPS,

September 2002):

■ Ten-year trend data for PM10 are not available before 1990,

because total suspended particulates, which include particle

sizes larger than PM10, were monitored until 1990.

■ The monitoring is conducted mostly in urban areas, 

although the PM2.5 data from the IMPROVE network support

assessments of rural trends from 1992 to 1999.

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-3, for more information.) 

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Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-13

Ozone is one of six criteria pollutants regularly monitored under

the CAA to determine compliance with health-based standards.

This indicator reflects ambient concentrations in parts per million

(ppm) of ground- level ozone from 1982 to 2001, based on 

1-hour and 8-hour measurements to gauge shorter-term and

longer-term levels.

The 1-hour standard is useful in measuring potential effects

during short-term “spikes” in concentrations. The longer 8-hour

standard is used in evaluating exposures occurring over a more

sustained period of time (e.g., an outdoor worker’s exposure

over the course of a work day).

What the Data Show

Although ozone concentrations are generally decreasing, they 

are higher than the NAAQS in many areas. Ground-level ozone

concentrations fell by 11 percent between 1982 and 2001,

based on the annual fourth highest daily maximum 8-hour 

average (Exhibit 1-9). Ozone levels based on the annual second

highest daily maximum 1-hour standard fell by 18 percent during

the same time (Exhibit 1-10). All regions experienced some

improvement in 8-hour ozone levels during the past 20 years

except the north central region (EPA Region 7), which showed 

little change (Exhibit 1-11) (EPA, OAQPS, September 2002).

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Ground-level ozone is not emitted directly into the air, but is

formed by the reaction of volatile organic compounds (VOCs)

and nitrogen oxides (NOX) in the presence of heat and

sunlight, particularly in hot summer weather. To assess ozone

trends, VOC and NOX emissions and meteorological

information are also evaluated.

■ The monitoring is conducted mostly in urban areas; 

therefore, data may not accurately encompass rural impacts

from ozone transport.

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-3, for more information.) 

Indicator Ambient concentrations of ozone: 8-hour and 1-hour – Category 1

0.00

0.05

0.10

0.15

0.20

82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

Concentration, ppm

1982–01: 11% decrease

1992–01: 0% change

NAAQS

10% of sites have concentrations below this line

90% of sites have concentrations below this line

Average

Exhibit 1-9: Ozone air quality, 1982–2001

based on annual 4th maximum 8–hour average

Coverage: 379 monitoring sites nationwide with sufficient data to assess trends.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

0.05

0.10

0.15

0.20

0.00

Average

Concentration, ppm

1982–01: 18% decrease

1992–01: 3% decrease

Exhibit 1-10: Ozone air quality, 1982–2001

based on annual 2nd maximum 1–hour average

NAAQS

10% of sites have concentrations below this line

90% of sites have concentrations below this line

Coverage: 379 monitoring sites nationwide with sufficient data to assess trends.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.
Indicator

1-14 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

Ambient concentrations of ozone: 8-hour and 1-hour – Category 1 (continued)

Exhibit 1-11: Trends in ozone levels (8-hour), 1982–2001, averaged across EPA regions

20%

8%

4%

2%

9%

0%

9%

9%

21%

24%

11%

1982 2001

.092 .082

1982 2001

.090 .082

1982 2001

.112 .090

1982 2001

.101 .093

1982 2001

.096 .092

1982 2001

.082 .080

1982 2001

.089 .081

1982 2001

.074 .074

1982 2001

.081 .074

1982 2001

.102 .078

1982 2001

.072 .057

The National Trend

Note: Alaska levels are included in EPA region 10 averages; Hawaii levels are included in EPA region 9 averages; and Puerto Rico levels are included in EPA region 

2 averages.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National Air Quality: 2001 Status and Trends. September 2002.

EPA Region 10

EPA Region 9

EPA Region 8

EPA Region 7

EPA Region 6

EPA Region 5

EPA Region 4

EPA Region 3

EPA Region 2

EPA Region 1

Based on annual 4th maximum 8-hour average Concentrations are in ppm

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Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-15

Lead is a metal found naturally in the environment as well as in

manufactured products. The major sources of lead emissions have

historically been motor vehicles and industrial sources. Due to 

the phase-out of leaded gasoline, metals processing is the major

source of lead emissions to the air today. The highest air 

concentrations of lead are usually found in the vicinity of 

smelters and battery manufacturers. Lead is a criteria and toxic 

air pollutant with significant health effects, as described in

Chapter 4, Human Health. 

What the Data Show

This indicator shows ambient lead concentrations measured in

μg/m3 per year from 1982 to 2001. Lead levels decreased by 94

percent in those years, largely because of regulations reducing the

lead content in gasoline (Exhibit 1-12) (EPA, OAQPS, September

2002). The most significant decline in ambient lead levels began

in the late 1970s and continued through the early 1980s.

Outdoor lead levels are below the NAAQS for most areas of the

U.S. (EPA, OAQPS, September 2002).

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Ambient lead monitoring is conducted mostly in urban areas, 

so it may not accurately encompass rural concentrations.

■ This indicator would be very useful in conjunction with

indicators of lead concentration in indoor air, drinking water,

and soil to portray a broad picture of potential sources of 

lead exposure. 

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-4, for more information.) 

Indicator Ambient concentrations of lead – Category 1 

82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

0.0

1.0

1.5

2.0

0.5

1982–01: 94% decrease

1992–01: 25% decrease

NAAQS

10% of sites have concentrations below this line

Average

90% of sites have concentrations below this line

Concentration, μg/m3

Exhibit 1-12: Lead air quality, 1982–2001

Based on annual maximum quarterly average

Coverage: 39 monitoring sites nationwide with sufficient data to assess trends.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

1.1.1.c What are the impacts of

air pollution on visibility in

national parks and other

protected lands?

Visibility is a measure of aesthetic value and the ability to enjoy scenic vistas, but it also can be an indicator of general air quality. PM is

the major contributor to reduced visibility, and high humidity levels

worsen the effects of pollution on visibility. The Interagency

Monitoring of Protected Visual Environments (IMPROVE) network

collects data to characterize visibility in protected lands. IMPROVE

was established in 1987 to:

■ Determine the type of pollutants primarily responsible for 

reduced visibility in protected areas.

■ Assess progress toward the Clean Air Act’s national goal of 

remedying existing and preventing future visibility impairment.

The indicator below presents data from the IMPROVE network on 

visibility trends for national parks and other protected lands.

Indicator

Visibility
Indicator

1-16 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

This indicator presents visibility trends for U.S. national parks and

wilderness areas in the eastern and western U.S. by mean visual

range, as measured in km for 1992 to 1999 and 1990 to 1999,

respectively, by worst, mid-range, and best visibility. Under the

Clean Air Act, a Class I area is one in which visibility is protected

more stringently than under the NAAQS, including national parks,

wilderness areas, monuments, and other areas of special national

and cultural significance. 

What the Data Show

Data collected by the IMPROVE network show that visibility for

the worst visibility days in the West is similar to days with the best

visibility in the East (Exhibit 1-13). In 1999, the mean visual range

for the worst days in the East was only 24 km (14.9 miles) compared to 84 km (52.2 miles) for the best visibility. In the West,

visibility impairment for the worst days remained relatively

unchanged over the 1990s, with the mean visual range for 1999

(80 km or 49.7 miles) nearly the same as the 1990 level (86 km

or 53.4 miles). Without the effects of pollution, a natural visual

range in the U.S. is approximately 75 to 150 km (47 to 93 miles)

in the East and 200 to 300 km (124 to 186 miles) in the West

(EPA, OAQPS, September 2002).

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ The indicator compares trends within visibility range categories,

but it would also be useful to indicate how often visibility falls

into each range during a year. 

■ The data represent only a sampling of national park and

wilderness areas; nevertheless, this indicator provides a good

picture of the impact of air pollution on the nation’s parks and

protected areas. As of 2001, the network monitored 110 sites. 

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-4, for more information.) 

Visibility – Category 1 

50

100

150

200

250

0

Year

Visual Range (km)Visual Range (km)

90 91 92 93 94 95 96 97 98 99

Best visibility

range is 177-208 km

Mid-Range

Best Visibility

50

100

150

200

250

0

92 93 94 95 96 97 98 99

Mid-Range

Mid-range visibility

is 118-133 km

Worst visibility

range is 73-85 km

Western U.S., 1990-1999 Eastern U.S., 1992-1999

Worst Visibility

Year

Best visibility

range is 79-90 km

Mid-range visibility

is 42-48 km

Worst visibility

range is 20-23 km

Best Visibility

Worst Visibility

Exhibit 1-13: Visibility trends for U.S. Class I areas

Note: Under the Clean Air Act, a Class I area is one in which visibility is protected more stringently than under the National Air Quality Standards (NAAQS), including national parks, 

wilderness areas, monuments, and other areas of special national and cultural significance. 

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National Air Quality: 2001 Status and Trends. September 2002.

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Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-17

1.1.1.d What are the

concentrations of toxic air

pollutants in ambient air?

Air toxics, also known as hazardous air pollutants, are pollutants that

may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological

effects. The Clean Air Act identifies 188 air toxics; some common

ones are perchloroethylene (from dry cleaners), mercury (from coal

combustion), methylene chloride (from consumer products such as

paint strippers), and benzene and 1,3-butadiene (from gasoline).

EPA does not set health-based standards for these pollutants;

instead, the Clean Air Act mandates a two-phased approach. In the

first phase, EPA establishes standards for source categories (major

sources, area sources, and mobile sources). In the second phase, EPA

assesses how well the standards are reducing health and environmental risks, and based on these assessments, determines what further

actions are necessary to address any significant remaining, or residual, health or environmental risks.

No formal monitoring network for air toxics currently exists, but several metropolitan areas do maintain monitoring programs. Data from

these areas provide the basis for an air toxics indicator. Metropolitan

areas with air toxics data generally show downward trends (EPA,

OAQPS, September 2002). However, although data and tools for

assessing risks from air toxics are limited, available evidence suggests

that emissions of air toxics may still pose significant health risks in

many areas throughout the U.S. (EPA, OAR, September 2002). In

addition to ambient concentrations of air toxics, an issue of particular concern is the deposition of toxic air pollutants to surface waterbodies. A pollutant of particular concern is mercury, which accumulates in fish tissue and in humans after they ingest contaminated fish

(see Chapter 2, Purer Water; and Chapter 5, Ecological Condition). 

Indicator

Ambient concentrations of selected air toxics

This indicator reflects data about annual average ambient concentrations of four selected air toxics, in μg/m3, derived from monitoring sites with sufficient trend data from 1994 to 1999.

Selected air toxics are benzene, 1,3-butadiene, total suspended

lead, and perchloroethylene (EPA, OAQPS, March 2001).

What the Data Show

Ambient concentrations of the selected air toxics—benzene, 

1,3-butadiene, total suspended lead, and perchlorethylene—

generally declined between 1994 and 1999, based on the annual

average from the reporting sites (EPA, OAQPS, March 2001). 

The lead concentration level is well below the NAAQS standard

(see Section 1.1.1.b in this chapter). Benzene levels, measured at

95 urban monitoring sites, decreased 47 percent from 1994 to

2000 (Exhibit 1-14) (EPA, OAQPS, September 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Information is limited because no formal network is currently 

in place for monitoring ambient concentrations of air toxics;

however, EPA and states are working to establish a national 

toxics monitoring network. 

■ The indicator reflects trends for selected air toxics, but not for

all 188 toxic air pollutants identified under the CAA.

■ More information is available for lead than for the other three

selected air toxics. Monitoring stations with sufficient trend

data for the other three compounds tend to be concentrated in

California, the Great Lakes, southern Texas, and the Northeast.

Data Sources

The data sources for this indicator were Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002, and National Air

Quality and Emissions Trends Report, 1999, EPA, 2001. (See

Appendix B, page B-4, for more information.) 

Indicator Ambient concentrations of selected air toxics – Category 2 

0

1

2

3

4

5

6

7

94 95 96 97 98 99 00

1994–00: 47% decrease

NAAQS

10% of sites have concentrations below this line

Average

90% of sites have concentrations below this line

Concentration, μg/m3 Coverage: 95 monitoring sites nationwide with sufficient data to assess trends.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

Exhibit 1-14: Ambient benzene, annual average urban 

concentrations, nationwide, 1994–2000
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1-18 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

1.1.2 What contributes to

outdoor air pollution?

Anthropogenic sources of air pollution range from “stationary

sources” such as factories, power plants, agricultural facilities, and

smelters, to smaller “area sources” such as dry cleaners and degreasing operations, to “mobile sources” such as cars, buses, planes,

trucks, trains, construction equipment, and lawn mowers. Naturally

occurring sources such as wind-blown dust, volcanoes, and wildfires

add to the total air pollution burden and may be significant on local

and regional scales. 

Most of the six criteria air pollutants show declining emissions since

1982. But as reported in Latest Findings on National Air Quality: 2001

Status and Trends, emissions of NOX, a contributor to ozone, PM,

and acid rain formation, increased by nine percent between 1982

and 2001, with a slight decrease (three percent) between 1992 and

2001 (EPA, OAQPS, September 2002). A significant amount of that

increase is attributed to growth in emissions from non-road engines,

including construction and recreation equipment and diesel vehicles.

EPA continuously reviews and improves estimates of pollutant emissions. Emissions estimates for criteria pollutants are currently under

such evaluation and may be updated.

1.1.2.a What are contributors to

particulate matter, ozone, and

lead in ambient air?

Two indicators are available to help answer this question: 

■ Emissions of particulate matter, sulfur dioxide, nitrogen oxide, and

volatile organic compounds.

■ Emissions of lead. 

Particulate matter can be emitted directly or formed in the atmosphere. “Primary” particles, such as dust from roads and elemental

carbon (soot) from wood combustion, are emitted directly into the

atmosphere. “Secondary” particles are formed in the atmosphere

from primary gaseous emissions. Examples include sulfates, formed

from SO2 emissions from power plants and industrial facilities, and

nitrates, formed from NOX emissions from power plants, automobiles, and other types of combustion sources. The chemical composition of particles depends on factors such as location, time of year,

and weather. 

The VOCs contributing to ozone formation are emitted from motor

vehicles, chemical plants, refineries, factories, consumer and commercial products such as paints and strippers, and other industrial

sources. Nitrogen oxides, also an ozone precursor, are emitted primarily from vehicles, power plants, and other combustion sources.

Smelters and battery manufacturers are the largest sources of lead in

outdoor air. 

Indicators

Emissions: particulate matter (PM2.5 and PM10), sulfur 

dioxide, nitrogen oxides, and volatile organic compounds

Lead emissions
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-19

This indicator includes the following data:

■ Direct PM emissions are measured in thousands of short tons

per year. PM10 emissions are presented from 1985 to 2001;

emissions of PM2.5 from 1992 to 2001.

■ Emissions of NOX, and SO2 presented from 1982 to 2001.

Emissions of NOX, contribute to nitrogen loading on land and

in water directly and as runoff from land. NOX, is also a precursor of ground-level ozone. Sulfates and nitrates, formed by

emissions of SO2 and NOX, contribute to acid deposition,

which can have significant impacts on aquatic life (see 

Chapter 2, Purer Water). 

■ Emissions of VOCs, also precursors of ground-level ozone.

These emissions, presented from 1982 to 2001, are measured

in thousands of short tons per year. 

What the Data Show

Direct emissions of PM10 fell by 13 percent between 1992 and

2001 (Exhibit 1-15). Emissions of direct PM2.5 also fell,

decreasing by 10 percent between 1992 and 2001 (Exhibit 

1-16). Sulfur dioxide emissions also decreased by 25 percent

between 1982 and 2001 and by 24 percent between 1992 and

2001 (Exhibit 1-17). However, emissions of NOX increased by 

9 percent between 1982 and 2001 and decreased by 3 percent

between 1992 and 2001 (Exhibit 1-18) (EPA, OAQPS,

September 2002). VOC emissions decreased by 16 percent

from 1982 to 2001 and by 8 percent from 1992 to 2001

(Exhibit 1-19) (EPA, OAQPS, September 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ The emissions indicators are estimates; however, consistent estimation methods can provide useful trend data. 

■ The methodology for estimating emissions is continually

reviewed and is subject to revision. EPA is currently conducting

such an evaluation of emissions data, and emissions estimates

may be updated. Trend data prior to these revisions must be

considered in the context of those changes.

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-5 for more information.) 

Indicator Emissions: particulate matter (PM2.5 and PM10), sulfur dioxide, nitrogen oxides, and volatile organic compounds – Category 2

Exhibit 1-16: Direct particulate matter (PM2.5) emissions, 

1992–2001

Thousand Short Tons

0

500

1,000

1,500

2,000

2,500

92 93 94 95 96 97 98 99 00 01

1992–01: 10% decrease

Fuel Combustion

Industrial Processes

Transportation

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

Fuel Combustion

Industrial Processes

Transportation

82 85 92 93 94 95 96 97 98 99 00 01

0

1,000

2,000

3,000

4,000

5,000

7,000

6,000

1992–01: 13% decrease

In 1985, EPA refined its methods for estimating emissions.

Thousand Short Tons

Emission

trends

data not

available.

Exhibit 1-15: Direct particulate matter (PM10)emissions, 

1985–2001

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.
Indicator

1-20 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

Emissions: particulate matter (PM2.5 and PM10), sulfur dioxide, nitrogen oxides, and volatile organic compounds – Category 2 (continued)

0

5,000

10,000

15,000

20,000

25,000

30,000

82 85 92 93 94 95 96 97 98 99 00 01

1982–01: 16% decrease

1992–01: 8% decrease

Exhibit 1-19: Volatile organic compounds (VOCs) 

 emissions, 1982–2001

Thousand Short Tons

In 1985, EPA refined its methods for estimating emissions.

Fuel Combustion

Industrial Processes

Transportation

Miscellaneous

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

Exhibit 1-18: Nitrogen oxides (NOx) emissions, 

1982–2001

0

5,000

10,000

15,000

20,000

25,000

30,000

82 85 92 93 94 95 96 97 98 99 00 01

Thousand Short Tons

1982–01: 9% increase

1992–01: 3% decrease

Fuel Combustion

Industrial Processes

Transportation

In 1985, EPA refined its methods for estimating emissions.

Miscellaneous

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

Exhibit 1-17: Sulfur dioxide (SO2) emissions, 1982–2001

0

5,000

10,000

15,000

20,000

25,000

30,000

82 85 92 93 94 95 96 97 98 99 00 01

1982–01: 25% decrease

1992–01: 24% decrease

Thousand Short Tons

Fuel Combustion

Industrial Processes

Transportation

In 1985, EPA refined its methods for estimating emissions.

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-21

This indicator is lead emissions from 1982 to 2001, measured in

short tons per year.

What the Data Show

Lead emissions decreased by 93 percent from 1982 to 2001 and

by 5 percent from 1992 to 2001 (Exhibit 1-20) (EPA, OAQPS,

September 2002). The transportation sector, particularly automotive sources, used to be the major source of lead emissions. The

phase-out of lead in gasoline resulted in great declines in lead

emissions from the transportation sector over the past 2 decades.

Today, industrial processes, primarily metals processing, are the

major source of lead emissions to the atmosphere. 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ The indicator does not present actual emissions data; thus, it

has the inherent limitations of estimates. However, consistent

estimation methods can provide useful trend data. 

■ Estimation is necessary for mobile sources and several areawide sources.

■ The methodology for estimating emissions is continually

reviewed and is subject to revision. Trend data for years prior to

revisions must be considered in the context of those changes. 

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-5, for more information.) 

Indicator Lead Emissions – Category 2

82 85 92 93 94 95 96 97 98 99 00 01

0

Short Tons

In 1985, EPA refined its methods for estimating emissions.

1982–01: 93% decrease

20,000

40,000

60,000

80,000

Exhibit 1-20: Lead emissions, 1982–2001

Fuel Combustion

Industrial Processes

Transportation

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-22 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

1.1.2.b What are contributors to

toxic air pollutants in ambient air?

An indicator for air toxics emissions is available to help address this

question. The Clean Air Act identifies 188 air toxics. EPA estimates

that more than 50 percent of air toxics emissions come from vehicles

and other mobile sources such as aircraft, locomotives, and construction equipment (EPA, OAQPS, September 2002). Other major

sources include industrial facilities and area sources such as small dry

cleaners and gas stations. Emissions of benzene, come from cars,

trucks, oil refineries, and chemical processes. Mercury emissions

come from coal combustion and waste incineration and can travel

thousands of miles before being deposited in water or on land (see

Chapter 2, Purer Water). Some air toxics are also released from natural sources such as volcanic eruptions and forest fires. 

Indicator

Air toxics emissions

This indicator is national air toxics emissions, in million of tons per

year, between the 1990-1993 baseline period and 1996. EPA

compiles an air toxics inventory as part of the National Emissions

Inventory, which focuses on four sectors—large industrial sources,

smaller industrial and natural sources, on-road mobile sources,

and non-road mobile sources. 

What the Data Show

Estimates show a 24 percent reduction in nationwide air toxics

emissions between the baseline period (1990-1993) and 1996—

a reduction from 6.11 million to 4.67 million tons per year

(Exhibit 1-21) (EPA, OAQPS, September 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Air toxics emissions estimates are currently available for only

1990 to 1993 (a mix of years depending on data availability on

various source types) and 1996. 

■ The emissions data are based on estimates that are not available on an annual basis. 

■ The indicator is an aggregate number; actual changes vary

among the toxic air pollutants and also vary from one part of

the country to another. 

Data Source

The data source for this indicator was Latest Findings on National

Air Quality: 2001 Status and Trends, EPA, 2002. (See Appendix B,

page B-6, for more information.) 

Indicator Air toxics emissions – Category 2

6.11

4.67

Exhibit 1-21: National air toxics emissions, 1990-1993, 

1996 (total for 188 toxic air pollutants)

33 Urban Air Toxics

155 Other Air Toxics

Baseline

(1990–1993)

1996

Million tons per year

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.0

Source: EPA, Office of Air Quality Planning and Standards. Latest Findings on National 

Air Quality: 2001 Status and Trends. September 2002.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.1 Outdoor Air Quality 1-23

1.1.2.c To what extent is U.S. air

quality the result of pollution from

other countries, and to what

extent does U.S. air pollution

affect other countries?

Air pollution does not recognize political boundaries: ozone and PM,

for example, can be transported hundreds or thousands of miles,

depending on weather conditions, including wind speeds. Canada

and the U.S. have jointly studied ground-level ozone occurrence and

transport in eastern North America. Eight-hour ozone measurements

for 1988 and 1995 from eastern Canada and the eastern U.S.

demonstrate how ozone travels in both directions across the U.S.-

Canadian border. The data suggested that ozone was being transported from urban to non-urban areas.

The U.S.-Canada Air Quality Committee studied the relative contribution of sources in each country to the ozone precursors–NOX and

VOCs. According to the report, “anthropogenic sources of NOX

emissions in the U.S. are ten times larger, and VOC emissions are 7

times larger in magnitude than in Canada, paralleling the relative

population ratio between the 2countries.” The study also showed

that wind speed can significantly affect ozone transport between the

two countries. At low wind speed (<3 meters per second), ozone

concentrations were high over major metropolitan areas or close to

the sources. At intermediate wind speeds (3 to 6 meters per second), overall concentrations were lower and ozone was transported

up to 500 km downwind. At higher wind speeds, higher concentrations were in downwind corners up to 1,000 km away (U.S.-Canada

Air Quality Committee, March 1999).

Transboundary air pollution issues are not limited to North America,

as demonstrated in the discussion of stratospheric ozone depletion

(see Section 1.4 in this chapter). More recently, the U.N.

Environment Programme suggested that the so-called Asian Brown

Cloud, a 2-mile-thick blanket of pollution over part of South Asia,

could travel halfway around the globe in a week (CNN, 2002).

No specific indicators have been identified at this time to address

the issue of transboundary air pollution.

1.1.3 What human health effects

are associated with outdoor air

pollution?

Outdoor air pollution can cause a variety of adverse health effects.

Exposure to air pollution can result in short-term health effects and

can also contribute to or aggravate chronic conditions. One such

condition is asthma, the leading chronic illness of children in the

U.S. and a leading cause of school absenteeism. In 2000, asthma

caused 465,000 hospitalizations and about 4,500 deaths in the

U.S. (CDC, 2003). Other chronic conditions to which air pollution

can contribute include lung cancer, asthma, respiratory disease, and

cardiovascular disease.

Some of the criteria pollutants, including ozone, NO2, and SO2, are

associated primarily with respiratory-related effects, including

aggravation of asthma and other respiratory diseases and irritation

of the lung and respiratory symptoms (e.g., cough, chest pain, difficulty breathing) (EPA, ORD, 1982,1986, August 1993, 1994).

Carbon monoxide, on the other hand, primarily affects people with

cardiovascular disease by reducing oxygen in the blood, leading to

aggravation of angina (EPA, ORD, NCEA, 2000). 

Short-term exposure to ozone has been linked to lung inflammation

and increased hospital admissions and emergency room visits (EPA,

ORD, NCEA, July 1996). Repeated short-term exposures to ozone

may damage children’s developing lungs and may lead to reduced

lung function later in life; long-term exposures to high ozone levels

are a possible cause of increased incidence of asthma in children

engaged in outdoor sports (McConnell, et al., 2002). Efforts to 

control automobile traffic in Atlanta during the 1996 Summer

Olympic Games were associated with a 28 percent reduction in peak

daily ozone concentrations during the Games and a significantly

lower rate of childhood asthma events (Friedman, et al., 2001).

When EPA introduced a new 8-hour ozone ambient standard in 

1997, it estimated that meeting the standard would reduce the risk

of significant decreases in children’s lung functions (such as difficulty

in breathing or shortness of breath) by about 1 million incidences

per year and would result in thousands of fewer hospital admissions

and visits for people with asthma (EPA, OAQPS, July 1997).

Exposure to airborne particulate matter is associated with a broader

range of health problems, including respiratory-related and cardiovascular effects. For example, short-term exposures to PM may 

aggravate asthma and bronchitis and have been associated with

heartbeat irregularities and heart attacks. PM exposures have been

linked to increased school absences and lost work days, hospital

admissions and emergency room visits, and even death from heart

and lung diseases (EPA, ORD, NCEA, April 1996). Long-term exposures have also been linked to deaths from heart and lung diseases,

including lung cancer (EPA, ORD, NCEA, 2002; Pope, et al., 2002). 

When EPA established new PM2.5 standards in 1997, it estimated

that meeting the standard would save about 15,000 lives each year,

especially among the elderly and those with existing heart and lung

diseases. The Agency said the new standard would reduce hospital

admissions by thousands each year; reduce risk of symptoms 

associated with chronic bronchitis by tens of thousands each year;

and avoid hundreds of thousands of incidences of asthma each year

(EPA, OAQPS, July 1997). 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-24 1.1 Outdoor Air Quality Chapter 1 - Cleaner Air

Lead, both a criteria pollutant and a toxic air pollutant, has significant health effects. Elevated blood lead levels are associated with

behavioral problems, neurological effects, and lowered IQ (EPA,

OAQPS, September 2002), The decrease in the average level of

lead in children’s blood reflects declines in ambient lead levels by

93 percent from 1982 to 2001—largely the result of regulations

reducing lead content in gasoline (EPA, OAQPS, September 2002).

Toxic or hazardous air pollutants may cause many other less common but potentially hazardous health effects, including cancer and

damage to the immune system, and neurological, reproductive, and

developmental problems. Acute exposure to some air toxics can

cause immediate death. Many of these pollutants can cause serious

health damages even at relatively low concentrations. National

emission standards have been established for eight of the 188 listed

hazardous air pollutants: asbestos, mercury, beryllium, benzene,

vinyl chloride, arsenic, radionuclides, and coke oven emissions.

The National-Scale Air Toxics Assessment, a nationwide analysis of

air toxics, develops health risk estimates for 33 toxic air pollutants

using computer modeling of the 1996 National Emissions Inventory

air toxics data. Based on the assessment, chromium, benzene, and

formaldehyde appear to pose the greatest nationwide carcinogenic

risk (EPA, OAR, September 2002). Benzene exposure has been linked

to increases in the risk of leukemia and multiple myeloma (EPA,

OAQPS, July 1995). 

No specific indicators have been identified at this time to address

the health effects associated with outdoor air pollution. For 

additional discussion of air pollution and associated health effects,

see Chapter 4, Human Health. 

1.1.4 What ecological effects are

associated with outdoor air

pollution?

Outdoor air not only has the potential to affect human health, but

also transports pollutants and deposits them onto soils or surface

waters. There, the pollutants can cause ecological effects and 

damage to property. Ground-level ozone damages plants and crops.

It interferes with the ability of plants to produce and store food,

reducing overall plant health and the ability to grow and reproduce.

The weakened plants are more susceptible to harsh weather, disease,

and pests. Through its effects on plants, ozone also can pose risks

to ecological functions such as water movement, mineral nutrient

cycling, and habitats for various animal and plant species (see

Chapter 5, Ecological Condition).

Airborne nitrogen species (including the criteria pollutants NO2 and

particulate nitrate) can contribute to excess nitrogen levels in

ecosystems. These excess nitrogen levels can result in: 

■ Changes in plant and soil community species diversity.

■ Altered community structure.

■ Eutrophication in surface and coastal waters. 

■ Acidified soils and waters (see Chapter 2, Purer Water). 

Airborne sulfur species (including the criteria pollutants SO2 and

particulate sulfate) can also contribute excess sulfur to ecosystems,

which can lead to acidification of the soils and related effects. When

deposited together, airborne nitrogen and sulfur species are known

as acid deposition. (See the discussion of acid deposition in Section

1.2 of this chapter.) 

Land and water can be contaminated by deposition of air toxics,

leading to contamination of plants and animals and, eventually, of

humans further up the food chain. Airborne mercury from incineration, for example, can settle in water and contaminate fish (see

Chapter 2, Purer Water). People who eat fish are then exposed to

mercury, which is known to be harmful to the nervous system.

No specific indicators have been identified at this time to address

the ecological effects associated with outdoor air pollution.

Additional discussion of the ecological effects associated with 

outdoor air pollution is found in Chapter 5, Ecological Condition.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.2 Acid Deposition 1-25

1.2 Acid Deposition

Sulfur dioxide and NOX emissions in the atmosphere react with

water, oxygen, and oxidants to form acidic components, also referred

to as acid deposition or “acid rain.” Air contaminants can be

deposited on land or water through precipitation (wet deposition) or

directly by dry deposition. Wet acid deposition is monitored by the

National Atmospheric Deposition Program/National Trends Network,

a cooperative program of federal and state agencies, universities,

electric utilities, and other industries. Dry deposition is measured by

the Clean Air Status and Trends Network (CASTNET), operated by

EPA and the National Park Service.

The acidity in precipitation in the eastern U.S. is at least twice as

high as in pre-industrial times (EPA, ORD, January 2003). To reduce

emissions of SO2 and NOX, EPA established the Acid Rain Program

under the Clean Air Act. This program focuses on the largest and

highest-emitting coal-fired power plants, which are significant contributors to acid deposition.

This section addresses the following questions:

■ What are the deposition rates of pollutants that cause acid rain?

(Section 1.2.1)

■ What are the emissions of pollutants that form acid rain? 

(Section 1.2.2)

■ What ecological effects are associated with acid deposition?

(Section 1.2.3)

1.2.1 What are the deposition

rates of pollutants that cause acid

rain?

Efforts to reduce sulfur dioxide and nitrogen oxides emissions from

power plants have helped to significantly reduce wet sulfate deposition and to contain increases in nitrogen deposition. Wet sulfate

deposition levels for 1999 to 2001 showed reductions of 20 to 30

percent compared to levels for 1989 to 1991 over widespread areas

in the Midwest and the Northeast, where acid rain has had its greatest impact. Nitrogen deposition levels showed no major changes.

Although NOX emissions from power plants decreased, nitrogen

emissions from sources other than power plants (e.g., motor vehicles,

non-road vehicles, and agricultural activities) increased between

1990 and 2001 (EPA, OAR, November 2002). 

Deposition of wet sulfate and wet nitrogen is the indicator used to

address this question.

Indicators

Deposition: wet sulfate and wet nitrogen
Indicator

1-26 1.2 Acid Deposition Chapter 1 - Cleaner Air

Measures of wet sulfate and wet nitrogen deposition in kilograms

per hectare (kg/ha), are a key indicator of acid deposition. 

What the Data Show

Wet sulfate decreased substantially throughout the Midwest and

Northeast between 1989-1991 and 1999-2001 (Exhibit 1-22).

By 2001, wet sulfate deposition had decreased more than 8 

kilograms per hectare (kg/ha) from 30-40 kg/ha/year in 1990 in

much of the Ohio River Valley and northeastern U.S. The greatest

reductions occurred in the mid-Appalachian region (EPA, OAR,

November 2002). 

There were no dramatic regional changes in wet nitrogen 

deposition between 1989-1991 and 1999-2001 (Exhibit 1-23).

Since 1990, nitrogen deposition decreased slightly in areas of

the eastern U.S., while increases occurred in some areas with 

significant agricultural activity (e.g., the Plains and coastal North

Carolina) or substantial mobile source emissions (e.g., southern

California). (EPA, OAR, November 2002).

Deposition: wet sulfate and wet nitrogen – Category 2

Coverage : 250 National Atmospheric Deposition Program National Trends Network (NADP/NTN) monitoring stations located throughout the lower 48 states.

Note: Map colors represent relative concentrations and do not imply ecological or human health status

Source: EPA, Office of Air and Radiation, Clean Air Markets Program. EPA Acid Rain Program: 2001 Progress Report. November 2002.

Exhibit 1-22: Wet sulfate deposition, 1989-1991 vs. 1999-2001

 Average of 1989-1991 Average of 1999-2001

(kg/ha)

>40

35

30

25

20

15

10

5

0

Wet SO42- Wet SO42-

(kg/ha)

>40

35

30

25

20

15

10

5

0

Coverage : 250 National Atmospheric Deposition Program National Trends Network (NADP/NTN) monitoring stations located throughout the lower 48 states.

Note: Map colors represent relative concentrations and do not imply ecological or human health status

Source: EPA, Office of Air and Radiation, Clean Air Markets Program. EPA Acid Rain Program: 2001 Progress Report. November 2002. 

Exhibit 1-23: Wet nitrogen deposition, 1989-1991 vs. 1999-2001

N

(kg/ha)

1

2

3

4

5

6

7

8

9

>10

N

(kg/ha)

1

2

3

4

5

6

7

8

9

>10

Average of 1989-1991 Average of 1999-2001

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.2 Acid Deposition 1-27

Wet and dry sulfur deposition make up roughly the same percentages of total sulfur deposition in the Midwest, whereas, in most

other areas, wet deposition makes up a greater percentage of the

total. Wet deposition also makes up most of the total nitrogen

deposition load at the majority of the monitoring sites in the

eastern U.S. In southern California, dry deposition makes up a

greater percentage of the total (Exhibit 1-24).

Using National Atmospheric Deposition Program data, a U.S.

Department of Agriculture (USDA) report on sustainable forests

observed that annual wet sulfate deposition decreased significantly between 1994 and 2000, especially in the North and South

Resource Planning Act regions, where deposition was the highest.

Nitrate deposition rates were lowest in the Pacific and Rocky

Mountain regions, where approximately 84 percent of the regions

experienced deposition rates of less than 4.2 pounds per acre

(4.8kg/ha) per year. Only 2 percent of the sites in the eastern

U.S. received less than that amount (USDA, FS, 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Geographic coverage is limited for measuring wet deposition

and even more so for measuring dry deposition. Additional

monitoring sites for both in coastal areas in the Southeast

would support improved measurement of nitrogen deposition

to estuaries. Additional dry deposition monitoring would 

provide a better understanding of acid deposition in the Ohio

Valley and Central and Rocky Mountain areas. 

■ Measurement techniques for dry deposition have improved 

substantially, but still lag behind operational wet deposition

techniques. 

Data Source

The data source for this indicator was EPA Acid Rain Program:

2001 Progress Report, EPA, 2002. (See Appendix B, page B-6, 

for more information.) 

Indicator Deposition: wet sulfate and wet nitrogen – Category 2 (continued)

Exhibit 1-24: Total sulfur and total nitrogen deposition, 2001

Sulfur Nitrogen

Coverage: 70 Clean Air Status and Trends Network (CASTNet) monitoring stations concentrated in the eastern half of the lower 48 states.

Note: The size of the "pies" indicates the total magnitude of deposition; the colors indicate the percentage of wet and dry deposition. 

Source: EPA, Office of Air and Radiation, Clean Air Markets Program. EPA Acid Rain Program: 2001 Progress Report. November 2002.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-28 1.2 Acid Deposition Chapter 1 - Cleaner Air

1.2.2 What are the emissions of

pollutants that form acid rain?

Acid deposition occurs when emissions of SO2 and NOX in the

atmosphere react with water, oxygen, and oxidants to form acidic

compounds. Electric utility plants that burn fossil fuels are a 

significant source of SO2 and NOX and monitor their emissions 

continuously. NOX is also emitted from other high-temperature 

combustion sources, including automobiles. 

The indicator used to address this question is emissions of sulfur

dioxide and nitrogen oxides from utilities. Indicators

Emissions (utility): sulfur dioxide and nitrogen oxides

This indicator is millions of tons of NOX and SO2 emissions from

sources covered under the Acid Rain Program from 1990 to 2001

and 1980 to 2001, respectively. These emissions data are an

important component of a market-based trading program to

reduce emissions and consequent impacts on the environment.

What the Data Show

SO2 emissions from sources covered under the Acid Rain Program

were 10.6 million tons in 2001, compared to 15.7 million tons in

1990. Emissions of NOX from these sources declined from 6.7

million tons in 1990 to 4.7 million tons in 2001 (Exhibit 1-25)

(EPA, OAR, June 2002).

Indicator Gaps and Limitations

Limitations of this indicator include the following:

■ Although electric utilities and large boilers are key sources of

SO2 and NOX, they are not the only sources. It is estimated

that about 64 percent of annual SO2 emissions and 26 percent

of NOX emissions are produced by electric utility plants that

burn fossil fuels (EPA, OAQPS, September 2002). 

■ Information on mobile source emissions is particularly useful for

completing the picture of NOX contributions to acid deposition.

Data Source

The data source for this indicator was EPA Acid Rain Program:

2001 Progress Report, Appendices A and B1, EPA, 2002. (See

Appendix B, page B-6, for more information.) 

Indicator Emissions (utility): sulfur dioxide and nitrogen oxides – Category 2

Exhibit 1-25: Power plant sulfur dioxide (SO2), 1980-2001, and 

nitrogen oxides (NOx), 1990-2001, emissions

1980 1985

17.3

16.1 15.7

11.9 11.2

1990

SO2 Emissions

1995 2000 2001

Millions of tons

20

15

10

5

0

1990 1996

NOx Emissions

1999 2000 2001

Millions of tons

8

6

4

2

0

10.6

6.7

5.9

5.5

5.1

4.7

Source: EPA, Office of Air and Radiation, Clean Air Markets Program. EPA Acid Rain Program: 2001 Progress Report. November 2002. Appendix A: Acid Rain Program - Year 2001 

SO2 Allowance Holdings and Deductions. (April 8, 2003; http://www.epa.gov/airmarkets/cmprpt/arp01/appendixa.pdf) and Appendix B1: 2001 Compliance Results for NOx 

Affected Units. (April 8, 2003; http://www.epa.gov/airmarkets/cmprpt/arp01/appendixb1.pdf).
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.3 Indoor Air Quality 1-29

1.2.3 What ecological effects are

associated with acid deposition?

Increased acid levels damage soils, lakes, and streams, rendering

some waterbodies unfit for certain fish and wildlife species. Indirect

effects of acid deposition are also responsible for damage to forest

ecosystems (see Chapter 5, Ecological Condition). Acidic ions in the

soil displace calcium and other nutrients from plant roots, inhibiting

growth. Acidic deposition can also mobilize toxic amounts of 

aluminum, increasing its availability for uptake by plants and by fish

and other aquatic life (EPA, OAR, November 2002). 

The nitrogen in acid rain adds to the total loading of nitrogen in waterbodies. As coastal ecosystems become overly rich in nitrogen, conditions

favor more frequent and more severe emergence of algal blooms, which

deplete oxygen, harming fish and reducing plant and animal diversity 

(see Chapter 2, Purer Water). 

A recent report assessing deposition-related changes in surface

water chemistry in the northern and eastern U.S. found that the

Clean Air Act has resulted in a large and widespread decrease in the

deposition of sulfur by approximately 40 percent in the 1990s. In

the same period, surface water sulfate concentrations declined in all

regions except the Ridge and Blue Ridge provinces (Virginia). Acid

neutralizing capacity (ANC), a key indicator of recovery, increased in

three of the regions (Adirondacks, Northern Appalachian Plateau

and Upper Midwest) and was unchanged in the New England and

the Ridge/Blue Ridge region. Modest increases in ANC have reduced

the number of acidic lakes and stream segments in some regions:

■ In the Adirondacks, 8.1 percent of lakes (150 lakes) were acidic in

2000. In the early 1990s, 13 percent (240 lakes) were acidic.

■ In the Upper Midwest, an estimated 80 of 250 lakes that were acidic

in the mid-1980s are no longer acidic.

■ In the Northern Appalachian Plateau region in 2000, there were an

estimated 3,393 kilometers (2,104 miles) of acidic streams in the

region, or 7.9 percent of the total population; this compares to 5,014

kilometers (3,109 miles) of acidic streams (12 percent) in 1993-94.

■ There was no evidence of recovery in New England, or in the Ridge

and Blue Ridge Provinces; the latter region is not expected to recover

immediately, due to the nature of forest soils in the province.

■ In the three regions showing recovery, approximately one-third of

formerly acidic surface waters are no longer acidic, although still

subject to episodes of acidification.

■ Nitrogen deposition levels changed little between 1989 and 2001,

and surface water nitrate concentrations are largely unchanged as well.

Nitrogen deposition remains a concern, because future increases in

surface water nitrate concentrations could retard surface water

recovery (EPA, ORD, January 2003).

No specific indicators have been identified at this time to address the

ecological effects associated with acid deposition.

1.3 Indoor Air Quality 

People in the U.S. spend 90 percent of their time indoors, and

indoor air pollutant levels may exceed those allowable outside.

Radon and environmental tobacco smoke (ETS) are the two indoor

air pollutants of greatest concern from a health perspective (EPA,

ORD, December 1992; NRC, 1988). 

Although methods to monitor and measure indoor air quality (IAQ)

exist, there is no practical way to assess the general quality of indoor

air nationwide. There are millions of residences, thousands of workplaces, and more than a hundred thousand schools in the U.S., and

representative samples are not practical because of cost and access

issues. This section, therefore, presents indoor air quality data from

limited studies, not from ongoing monitoring efforts. 

This section addresses the following questions:

■ What is the quality of the air in buildings in the United States?

(Section 1.3.1)

■ What contributes to indoor air pollution? (Section 1.3.2)

■ What human health effects are associated with indoor air 

pollution? (Section 1.3.3)

1.3.1 What is the quality of the air

in buildings in the United States?

While it is difficult to make general statements about the quality of

indoor air nationwide, two studies–the National Residential Radon

Survey and an analysis of ETS exposure based on data from the

National Health Interview Survey–offer important insights. These

studies provide data about residential levels of radon and ETS, 

presented in the description of two indicators on the following pages.

In addition, several studies have attempted to characterize environmental issues inside office buildings and schools. The Building

Assessment Survey and Evaluation (BASE) study, conducted from

1994 to 1998, is a study of office IAQ. The study was designed 

with input from more than 40 national IAQ experts and reviewed by

the EPA Science Advisory Board. The consensus of these national

experts was that a sample of 100 to 200 office buildings would be

sufficient to characterize the central tendency of IAQ in office 

buildings nationwide.

Limited information about IAQ in schools is available from a 1999

survey of about 900 public schools by the National Center for

Education Statistics. This survey addressed concerns related to 

Indicators

U.S. homes above EPA’s radon action levels

Percentage of homes where young children are exposed to 

environmental tobacco smoke
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1-30 1.3 Indoor Air Quality Chapter 1 - Cleaner Air

environmental conditions, defined as lighting, heating, ventilation,

IAQ, acoustics or noise control, and physical security of buildings. In

all, 43 percent of schools responded that at least one environmental

condition was unsatisfactory. Ventilation was the most often cited

environmental issue of concern (DOE, NCES, 2000).

In addition to the indoor pollutants discussed above, pesticides

also may pose IAQ concerns. Approximately three-quarters of U.S.

households use at least one pesticide product indoors during the

course of a year. Products used most often are insecticides and

disinfectants. The EPA Nonoccupational Pesticide Exposure Study

(NOPES), published in 1990, assessed exposure to airborne pesticides in Jacksonville, Florida, and in Springfield and Chicopee,

Massachusetts. Indoor sources accounted for 90 percent or more

of the total airborne exposure to most of these pesticides. NOPES

found that tested households had at least 5 pesticides in indoor air,

at levels often 10 times greater than levels measured in outdoor air

(EPA, AREAL, January 1990). Some of the pesticides had been

banned or otherwise regulated by EPA (e.g., aldrin, dieldrin,

heptachlor, and chlordane), but continued to be found in the

homes. Since these pesticides previously were widely used to

prevent termites, they are believed to have entered the homes via

diffusion of soil gas into basements, similar to the way radon enters

homes. Another pesticide, DDT, banned for nearly 20 years, was

found in house dust in five out of eight homes (EPA, AREAL, January

1990). Later studies, including measurements in soil just outside

the home, suggested that DDT and other long-lasting pesticides

can be tracked in from soil clinging to shoes.

No comprehensive nationwide information is available on the amount

of pesticides used in the nation’s 11,000 public schools. The federal

government has not collected such data, and only one state,

Louisiana, requires its school districts to specifically report the

amount of pesticides used (GAO, 1999).

This report uses two indicators, discussed below, to address 

the question, “What is the quality of air in the buildings in the

United States?”:

■ U.S. homes above EPA radon action levels.

■ Percentage of homes where young children are exposed to ETS.

Naturally occurring radon gas is formed by the decay of uranium

in rock, soil, and water. Radon enters a home by moving up from

rock and soil and into the building through cracks or other holes

in the foundation. 

The amount of radon gas in the air is measured in picocuries

per liter of air or pCi/L. EPA has set a recommended “action

level” of four pCi/L for homes and schools to reduce the risk of

lung cancer.

What the Data Show

A 1991 representative survey of all housing units in the United

States estimated that six percent of U.S. homes (5.8 million in

1990) had an annual average radon level of more than four picocuries per liter (pCi/L) in indoor air. Also, about 56 percent of

Americans’ exposure to radon occurs in homes with two pCi/L or

more. Single-family detached homes were four times more likely to

require mitigation than multi-family homes. The survey’s findings

were used in constructing EPA’s estimate of U.S. lung cancer risks

from radon, in setting the four pCi/L action level, and in crafting

testing and mitigation guidance for the American public (EPA,

OAR, October 1992).

Indicator Data Gaps and Limitations

The study is several years old and may not reflect changes

brought about as a result of significant EPA radon public 

education campaigns since that time. Since the mid-1980s,

about 18 million homes have been tested for radon and about

700,000 of them have been mitigated. In addition, since 1990

approximately one million new homes have been built with

radon-resistant features.

Data Source

The data source for this indicator was National Radon Residential

Survey: Summary Report EPA, 1992. (See Appendix B, page B-7, 

for more information.) 

Indicator U.S. homes above EPA’s radon action levels – Category 2
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Chapter 1 - Cleaner Air 1.3 Indoor Air Quality 1-31

Environmental tobacco smoke (ETS)—smoke emitted from the

burning end of a cigarette, pipe, or cigar, and smoke exhaled by

a smoker—is a complex mix of more than 4,000 chemical compounds, containing many known or suspected carcinogens and

toxic agents, including particles, carbon monoxide, and

formaldehyde.

What the Data Show

The National Center for Health Statistics has conducted a major

nationwide survey, known as the National Health Interview Survey,

continuously since 1957. The survey estimated that in 1998,

young children were exposed to ETS in 20 percent of homes in

the U.S.—down from approximately 39 percent in 1986. About

43,000 households and 106,000 people participated in the 

survey (DHHS, NCHS, 2001).

Indicator Data Gaps and Limitations

The estimate is not based on a specific question about children’s

exposure to ETS, but rather is calculated based on the number of

houses with smokers and with children.

Data Source

The data source for this indicator was Healthy People 2000 Final

Review, Department of Health and Human Services, National

Center for Health Statistics, 2001. (See Appendix B, page B-7, 

for more information.) 

Indicator Percentage of homes where young children are exposed to environmental tobacco smoke –

Category 2

1.3.2 What contributes to indoor

air pollution?

Indoor air pollutants come from a wide array of sources. In considering the potential impact of these sources on indoor air quality, it is

vital to recognize the exchange between indoor and outdoor air.

Exchange rates vary considerably from building to building, from one

part of the country to another, and by seasons. Tight building construction improves energy efficiency but reduces indoor-outdoor air

exchange and may contribute to indoor air pollution. 

Among the sources of indoor air pollution are:

■ Combustion of fuel used for heating and cooking, including oil,

gas, kerosene, coal, and wood.

■ Environmental tobacco smoke.

■ Some adhesives, paints, and coatings (building materials). 

■ Furniture made of certain pressed wood products. 

■ Deteriorated, asbestos-containing insulation.

■ Some products for household cleaning and maintenance, personal

care, or hobbies.

■ Inadequate maintenance of central heating and cooling systems.

■ Radon, pesticides, and outdoor air pollution.

■ Biological sources, including animal dander, cockroaches, dust

mites, molds, and fungi.

1.3.3 What human health effects

are associated with indoor air

pollution?

In general, indoor air pollution can cause headaches, tiredness, dizziness, nausea, and throat irritation. More serious effects include cancer and exacerbation of chronic respiratory diseases, such as asthma.

The most sensitive and vulnerable population groups—the elderly,

the young, and the infirm—tend to spend the most time indoors;

therefore, they may face higher than usual exposures.

Radon is estimated to be the second leading cause of lung cancer in

the U.S. In an EPA-sponsored study, the National Research Council

(NRC) found between 15,000 and 22,000 radon-related lung cancer deaths annually in the U.S. (NRC, 1998). 

Environmental tobacco smoke causes eye, nose, and throat irritation,

and is a carcinogen. Children exposed to ETS are at increased risk

for respiratory problems and experience increased episodes of asthma (Mannino, et al., 2001). In studies of lifelong nonsmoking

women, there was a 24 percent excess risk of lung cancer as a result

of ETS exposures from a spouse’s smoking (Hackshaw, 1998).

Asthma, particularly in children, is associated with poor indoor air

quality. Dust mite proliferation in moist indoor environments can

lead to asthma attacks. Other allergens and irritants such as animal

dander, ETS, pesticide sprays, cockroach particles, and chemical

fumes from household products have also been shown to increase

asthma attack rates (IOM, 2000). 
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1-32 1.4 Stratospheric Ozone Chapter 1 - Cleaner Air

Fungal spores from mold growth in moist areas in homes have been

associated with health effects in occupants, including allergies and

asthma (IOM, 1993). Headaches, respiratory distress, and cardiovascular effects are also associated with exposure to molds. 

No specific indicators have been identified at this time to address

the human health effects associated with indoor air pollution.

1.4 Stratospheric Ozone 

Although ozone is a harmful pollutant at ground level, it plays a

valuable role in the stratosphere–the part of the atmosphere at an

altitude of 10 to 30 km–by filtering harmful radiation from the

sun. The sun’s radiation bathes the Earth in ultraviolet (UV) wavelengths of 150 to 400 nanometers (nm). Ultraviolet radiation in

the band between 280 and 320 nm, known as UV-B, is harmful to

most organisms.

About 90 percent of the planet’s ozone at a given time is in a thin

layer of the lower stratosphere called the ozone layer, which also

includes other gases. Ozone is constantly being created and

destroyed by UV radiation. About 95 to 99 percent of UV-B radiation that reaches the Earth’s surface is absorbed by ozone and oxygen in the ozone layer (NASA, 2002).

The ozone layer varies in space and time and is highly susceptible

to changes in atmospheric chemical reactions by which it is 

created and destroyed. Scientists in the 1970s and 1980s 

discovered that human-caused changes to the composition of 

the atmosphere were leading to depletion of stratospheric ozone

(NASA, 2002). They initially identified chlorofluorocarbons

(CFCs) as being particularly significant stratospheric ozone

depleters. Scientists subsequently identified additional humanproduced ozone-depleting substances (ODSs).

This section poses four questions about stratospheric ozone:

■ What are the trends in the Earth’s ozone layer? (Section 1.4.1)

■ What is causing changes to the ozone layer? (Section 1.4.2)

■ What human health effects are associated with stratospheric

ozone depletion? (Section 1.4.3)

■ What ecological effects are associated with stratospheric ozone

depletion? (Section 1.4.4)

1.4.1 What are the trends in the

Earth’s ozone layer? 

The most recent authoritative assessment of the Earth’s stratospheric ozone is the Scientific Assessment of Ozone Depletion: 2002

(Scientific Assessment Panel, 2003), conducted under the auspices of the United Nations Environment Programme (UNEP) and

the World Meteorological Organization (WMO). The study found

an average decrease of about 6 percent in average ozone concentrations between 35 and 60 degrees South for the period 1997 to

2001, compared with pre-1980 average values. It also found an

Indicators

Ozone levels over North America
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Chapter 1 - Cleaner Air 1.4 Stratospheric Ozone 1-33

average decrease of 3 percent between 35 and 60 degrees North

for the same period (Scientific Assessment Panel, 2003). 

It is generally believed that, after years of continuing thinning of the

stratospheric ozone layer, the ozone layer will recover over the next

several years as a result of international controls of ODSs. The

Montreal Protocol on Substances that Deplete the Ozone Layer

(Montreal Protocol), for example, restricts global manufacturing of

CFCs (Scientific Assessment Panel, 2003).

Scientists largely agree that a thinning of the stratospheric ozone

layer causes an increase in the amount of UV radiation, especially

UV-B, that reaches the Earth’s surface. This outcome is consistent

with theories about the physical processes involved, measurable

locally by ground-based and satellite-based instruments. 

While acknowledging high uncertainty in the estimates, it is estimated that UV irradiance has increased since the early 1980s by 6 to 14

percent at more than ten sites distributed over mid and high latitudes of both hemispheres. Over the past two decades, UV increases

are believed to have been considerably greater at higher latitudes. In

the Northern Hemisphere, they are believed to be greater in the winter/spring than in the summer/fall (Scientific Assessment Panel,

2003). The estimates of increasing UV-B levels are based on indirect

methods and models rather than direct measurements.

Because of the phase-out of ODS, total stratospheric concentrations

of ODS seem to have peaked; it is believed that stratospheric ozone

concentrations, near the lowest point since systematic measurements

began, will not decrease any further and will eventually recover.

These developments lead to the conclusion that UV radiation levels

reaching the Earth’s surface are close to the maximum they will reach

as a result of human-induced stratospheric ozone depletion

(Scientific Assessment Panel, 2003).

Obtaining reliable measurements of broad trends in levels of UV 

radiation reaching ground level in North America, however, is a complex task. It is particularly challenging to measure in ways that highlight the relationship between ozone depletion and UV radiation.

The amount of incoming UV radiation is affected by several variables,

including latitude, season, time of day, snow cover, sea ice cover, 

surface reflectivity, altitude, clouds, and aerosols. Determining which

portion of any change is attributable to ozone depletion is difficult.

The indicator used to address the extent of change to the ozone

layer is ozone levels over North America.

Data mapped for this indicator are derived from the Total Ozone

Mapping Spectrometer (TOMS), flown on NASA’s Nimbus-7

satellite. The TOMS measures amounts of backscattered UV 

radiation at various wavelengths. Backscattered radiation levels 

at wavelengths where ozone absorption does and does not take

place are compared with radiation directly from the sun at the

same wavelengths, allowing scientists to derive a “total ozone”

amount in the Earth’s atmosphere.

The data for this indicator are presented in Dobson Units (DU)

which measure how thick the ozone layer would be if compressed

in the Earth’s atmosphere (at sea level and at 0°C.) One DU is

defined to be 0.01 mm thickness at standard temperature and

pressure.

What the Data Show

The ozone maps illustrate graphically and quantitatively the thinning of total column ozone over North America during a 15-year

period. For example, in 1979, the ozone column over the Seattle

area was 391 Dobson Units (DU), but in 1994 it had dropped to

360 DU. Over Los Angeles, the ozone column during that time

dropped from 368 DU to 330 DU, and over Miami from 303 DU

to 296 DU (Exhibit 1-26) (NASA, March 1979 and March

1994). Although exact calculations cannot be made from Exhibit

1-26, the graph demonstrates thinning of the ozone layer over

much of the globe.

In general, ozone depletion is greater at higher latitudes.

Therefore, it is predictable that the decrease in the ozone layer

over Seattle is greater than over Los Angeles, with the ozone layer

over Miami experiencing the lowest depletion among the three

cities. However, southern cities also have higher levels of UV-B, so

even with less depletion, the net increase in UV-B can exceed that

over northern latitudes.

According to the latest estimates in the Scientific Assessment, the

global-average total column ozone during 1997 to 2001 was

about 3 percent below average pre-1980 values (Scientific

Indicator Ozone levels over North America, – Category 1
Indicator

1-34 1.4 Stratospheric Ozone Chapter 1 - Cleaner Air

Assessment Panel, 2003). Trends over North America reflect this

global phenomenon.

Indicator Gaps and Limitations

TOMS provides no data during nighttime or during the longer

periods of darkness in polar regions.

Data Source

The data source for this indicator was NASA, Total Ozone

Mapping Spectrometer, flown on the Nimbus-7 satellite. March

1979 and March 1994. (See Appendix B, page B-7, for more

information.) 

Ozone levels over North America, March 1979 and March 1994 – Category 1 (continued)

Source: NASA, Goddard Space Flight Center. Total Ozone Mapping Spectrometer (TOMS), 

flown on Nimbus-7 satellite. (January 24, 2003; 

Available: http://www.epa.gov/ozone/science/glob_dep.html).

Exhibit 1-26: Ozone levels over North America, 1979 and 1994

Seattle

Los Angeles

Miami

Seattle

Los Angeles

Miami March 1979 March 1984

Dobson 

Units

200

250

300

350

400

450

1.4.2 What is causing changes to

the ozone layer?

Analyses have shown that the presence of CFCs and other ODSs was

negligible before commercial production of CFCs and other ODSs

began in the 1930s and 1940s (Scientific Assessment Panel, 2003).

The adoption of the 1987 Montreal Protocol significantly affected

production levels, resulting in reduced concentrations of ODSs.

Worldwide emissions are estimated to have been reduced significantly, since peaking in 1993 (Scientific Assessment Panel, 2003).

Likewise, there have been marked decreases in U.S. emissions of

ODSs over the past decade, resulting in a 79 percent decrease in

total ODP-weighted emissions from 1990 to 2000 (EPA, OAP, 

April 2002). 

Two indicators are used to address this question:

■ Worldwide and U.S. production of ODSs.

■ Concentration of ODSs (effective equivalent stratospheric 

chlorine).

Indicators

Worldwide and U.S. production of ozone-depleting substances

(ODSs)

Concentrations of ozone-depleting substances (effective

equivalent chlorine)

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Chapter 1 - Cleaner Air 1.4 Stratospheric Ozone 1-35

Worldwide ODS production estimates are derived from reports

produced by each nation, as required under the Montreal Protocol

and subsequent amendments. 

Production, consumption, and emissions of ODSs are not identical; even though the ultimate destiny of a given pound of CFCs

might be release to the atmosphere, a time lag is involved. ODSs

initially are contained—and isolated from the atmosphere—after

they are produced. They are likely to stay contained until they are

consumed—for example, used as coolant in a refrigerator or as a

foaming agent in polystyrene-foam hot cups. Once they are consumed, the ODSs still might not be released to the atmosphere

until years later, such as when the cup degrades in a landfill, or

when the refrigerator is disposed of or recycled (at which time the

ODS may actually be reclaimed for further use).

Because of these complexities, consumption and emissions figures

involve significant uncertainties—they are estimated based on

rates of conversion. Production figures may be more meaningful,

because they are compiled from data which a relatively small 

number of producing companies must report by law. 

What the Data Show

There have been marked decreases in worldwide production, and

consumption of ODSs over the past 2 decades (Exhibit 1-27).

Worldwide ODS production declined from approximately 1.8 

million tons in 1986 to 313,000 tons in 1999 (UNEP, 2002).

Worldwide measures are presented in ozone depletion potential

(ODP)-weighted tons. Each ODS is weighted based on its damage

to the stratospheric ozone; this is its ODP. U.S. production of

selected ODSs peaked in 1988 and declined by nearly 65 percent

in 5 years (Exhibit 1- 28) (USITC, 1994). 

Indicator Gaps and Limitations

In some cases ODS production data are reliable because laws

require that they be reported. Coverage from nation to nation is

incomplete, however, and sometimes methods are inconsistent.

Production estimates for the U.S. are generally reliable as a result

of the legal reporting requirement for production figures and the

small number of producers involved.

Data Sources

The data sources for this indicator were Worldwide Estimates:

Production and Consumption of Ozone Depleting Substances 1986-

2000, Ozone Secretariat/UNEP, 2002, and 1993 Synthetic

Organic Chemicals; U.S. Production and Sales, U.S. International

Trade Commission, 1994. (See Appendix B, page B-7, for more

information.) 

Indicator Worldwide and U.S. production of ozone-depleting substances (ODSs) – Category 2

Exhibit 1-27: Worldwide ODS production and

consumption (ODP-weighted tons), 1986 and 1999

Source: United Nations Environment Programme, Ozone Secretariat. Production and 

Consumption of Ozone Depleting Substances under the Montreal Protocol: 1986-2000. 

April 2002.

Year Production Consumption

1,784,015

275,382

1986

1999

1,768,789

312,731

0

50

100

150

200

250

300

350

400

450

1958 1963 1968 1973 1978 1983 1988 1993

CFC-11 CFC-12 CFC-113 HCFC-22 CH3CCL3

Source: U.S. International Trade Commission. 1993 Synthetic Organic Chemicals; U.S. Production and Sales. 1994 (July 3, 2002; 

http://www.epa.gov/ozone/science/indicat/index.html). (thousand metric tons of CFC-11 equivalent)

Exhibit 1-28: U.S. production of selected ozone-depleting chemicals, 1958-1993
Indicator

1-36 1.4 Stratospheric Ozone Chapter 1 - Cleaner Air

Effective equivalent chlorine (EECl), the amount of chlorine and

bromine in the lower atmosphere, is used to represent concentrations of ozone-depleting substances. It is a convenient parameter

for measuring with a single number the overall potential human

effect on stratospheric ozone. EECl is derived by considering the

changing concentrations of about a dozen gases that can affect

the stratospheric ozone concentration. An index is then developed

based on the ability of those gases to catalyze the destruction of

ozone relative to the ability of chlorine to do so. The units of EECl

are parts per trillion by volume.

What the Data Show

The Scientific Assessment states that the total effect of all ozonedepleting halogens in the atmosphere, estimated by calculating

chlorine equivalents from atmospheric measurements of chlorineand bromine- containing gases, continues to decrease. As of mid2000, equivalent organic chlorine in the troposphere was nearly

five percent below the peak value in 1992 to 1994 (Exhibit 1-

29). The recent decrease is slightly slower than in the mid-1990s

due to the reduced influence of methyl chloroform on this decline

(Scientific Assessment Panel, 2003).

In 1996, EPA measurements indicated that concentrations of

methyl chloroform had started to fall, indicating that emissions

had been reduced. Concentrations of other ozone-depleting substances in the upper layers of the atmosphere, like CFCs, are also

beginning to decrease. Stratospheric chlorine levels have apparently peaked and are expected to slowly decline in coming years

(EPA, OAQPS, September 2002). The best current estimate from

computer models is that the atmospheric burden of halogens will

return to 1980 levels (pre-Antarctic ozone hole) around the middle of this century if the Montreal Protocol and its Amendments

are fully adhered to (Scientific Assessment Panel, 2003).

Indicator Gaps and Limitations

The precision of this indicator depends on understanding the

chemistry and behavior of the many different gases involved. For

example, accurate estimates of the atmospheric lifetime of a gas

are essential to assigning it the proper weight relative to other

gases. As scientific understanding of atmospheric chemistry

improves, calculations continue to be refined. 

Data Source

The data source for this indicator was Scientific Assessment of

Ozone Depletion: 2002, Scientific Assessment Panel of the

Montreal Protocol on Substances that Deplete the Ozone Layer,

WMO, 2003. (See Appendix B, page B-8, for more information.) 

Concentrations of ozone-depleting substances (effective equivalent chlorine) – Category 2 

2000

2050

2100

2150

2200

2250

2300

ppt

1991 1993 1995 1997 1999 2001

Exhibit 1-29: Global total effective 

equivalent chlorine (EECI), 1992-2002 

Source: Updated from Montzka, Stephen A., et al. Present and future trends in the 

atmospheric burden of ozone-depleting halogens. April 1999;

NOAA, Climate Monitoring & Diagnostics Laboratory. Halocarbons and other 

Atmospheric Trace Species (HATS). 2002. March 18, 2003; 

http://www.cmdl.noaa.gov/hats/graphs/graphs.html).

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Chapter 1 - Cleaner Air 1.4 Stratospheric Ozone 1-37

1.4.3 What human health effects

are associated with stratospheric

ozone depletion? 

The increased ground-level UV radiation that can result from stratospheric ozone depletion is expected to have significant adverse human

health effects. UV-B radiation is linked to skin cancer, increased incidence of cataracts, and suppression of the immune system (EPA,

OAQPS, September 2002). Approximately 1.3 million new cases of

skin cancer are diagnosed every year in the U.S., according to the

Centers for Disease Control and Prevention (CDC) and the American

Cancer Society. Malignant melanoma accounts for about 75 percent

of the approximately 9,800 skin cancer deaths in the U.S. annually.

The incidence rate of malignant melanoma is increasing by about 3

percent annually, although death rates have remained constant

(Wingo, et al., 1999). 

Possible increased UV radiation levels is only one of many factors

that could affect skin cancer incidence. Others include behavioral

changes (people spending more time at the beach or outdoors) and

changes in screening for, diagnosis of, and reporting of the disease.

Data on UV-B radiation and tropospheric ozone are used to calculate

benefits from accelerated phase-out schedules for ODSs. EPA 

Exhibit 1-30: Estimated benefits of phaseout of ozone-depleting substances 

(sections 604, 606, and 609 of the Clean Air Act)

■ Melanoma and nonmelanoma skin 

cancer (fatal)

6.3 million lives saved from skin cancer in the U.S. between 1990 and 2165Dose-response function based on UV exposure and demographics of exposed populations1

Notes: 

1) For more detail see EPA's Regulatory Impact Analysis: Protection of Stratospheric Ozone (1988).

2) Note that the ecological effects, unlike the health effects, do not reflect the accelerated reduction and phaseout schedule of section 606.

3) Benefits due to the section 606 methyl bromide phaseout are not included in the benefits total because EPA provides neither annual incidence estimates nor a monetary 

value. The EPA does provide, however, a total estimate of 2,800 avoided skin cancer fatalities in the U.S.

Source: EPA, Office of Air and Radiation. The Benefits and Costs of the Clean Air Act 1990 to 2010. EPA Report to Congress. November 1999.

Health Effects - Quantified Estimate Basis for Estimate

Ecological Effects - Quantified Estimate Basis for Estimate

■ Melanoma and nonmelanoma skin 

cancer (non-fatal)

299 million avoided cases of non-fatal skin cancers in the 

U.S. between 1990 and 2165 

Dose-response function based on UV exposure and demographics of exposed populations1

■ Cataracts 27.5 million avoided cases in the U.S. between 1990 and 

2165 

Dose-response function uses a multivariate logistic risk function 

based on demographic characteristics and medical history1

■ American crop harvests Avoided 7.5 percent decrease from UV-b radiation by 

2075

Dose-response sources: Teramura and Murali (1986), Rowe 

and Adams (1987)

Health Effects - Unquantified

Ecological Effects - Unquantified

Benefits to people and the environment outside the U.S.

Effects, both ecological and human health, associated with global warming

■ American crops Avoided decrease from tropospheric ozone Estimate of increase in troposhpheric ozone: Whitten and Gery 

(1986). Dose-response source: Rowe and Adams (1987)

■ Polymers Avoided damage to materials from UV-b radiation

Skin cancer: reduced pain and suffering

Reduced morbidity effects of increased UV. For example:

■ reduced actinic keratosis (pre-cancerous lesions resulting from excessive sun exposure)

■ reduced immune system suppression

Ecological effects of UV. For example, benefits relating to the following:

■ recreational fishing

■ forests

■ overall marine ecosystem

■ avoided sea level rise, including avoided beach erosion, loss of coastal 

wetlands, salinity of estuaries and aquifers

■ other crops

■ other plant species

■ fish harvests

Source of UV-b/stabilizer relationship; Horst (1986)

Ecological benefits of reduced trophospheric ozone relating to the overall marine ecosystem, forests, mand-made materials, crops, other plant species, and fish harvests
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-38 1.5 Climate Change Chapter 1 - Cleaner Air

estimates that between 1990 and 2165, in the U.S. alone 6.3 million

fatal skin cancers, 299 million cases of non-fatal skin cancers, and

27.5 million cases of cataracts will be prevented because of the

worldwide phase-out of ODSs. (EPA, OAR, November 1999) 

(Exhibit 1-30). These are estimated cumulative effects, so there are

no data series or trends to evaluate.

No specific indicators have been identified at this time for human

health effects of stratospheric ozone depletion. 

1.4.4 What ecological effects are

associated with stratospheric

ozone depletion? 

UV radiation in sunlight affects the physiological and developmental

processes of plants. Even though plants have mechanisms to reduce

or repair these effects and some ability to adapt to increased UV-B

levels, UV radiation can still directly affect plant growth. It can also

produce indirect effects such as changes in plant form, distribution

of nutrients within the plant, timing of developmental phases, and

secondary metabolism. These changes can be even more important

than direct damage because of their implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles

(UNEP, 1994).

UV radiation can also affect aquatic life. UV exposure affects both

orientation mechanisms and motility in phytoplankton, resulting in

reduced survival rates for these organisms. Scientists have demonstrated a direct reduction in phytoplankton production as a result of

ozone depletion-related increases in UV-B (DeMora, et al., 2000).

Small increases in UV-B radiation have been found to cause damage

in the early developmental stages of fish, shrimp, crab, amphibians,

and other animals, the most severe effects being decreased reproductive capacity and impaired larval development. Animals higher on

the food chain that depend on these organisms for food could, in

turn, be affected (UNEP, 1994). 

Increases in UV radiation could also affect terrestrial and aquatic

biogeochemical cycles, and, as a result, alter both sources and sinks

of greenhouse and chemically important trace gases. These potential

changes would contribute to biosphere-atmosphere feedback that

attenuates or reinforces the atmospheric buildup of these gases

(UNEP, 1994). Synthetic polymers, naturally occurring biopolymers,

and some other materials of commercial interest also are adversely

affected by UV radiation, but special additives somewhat protect

some modern materials from UV-B. Increases in UV-B levels nonetheless will likely accelerate their breakdown, limiting their usefulness

outdoors (UNEP, 1994). 

No specific indicators have been identified at this time to address

the ecological effects associated with stratospheric ozone depletion.

1.5 Climate Change

The issue of global climate change involves changes in the radiative

balance of the Earth–the balance between energy received from the

sun and emitted from the Earth. This report does not attempt to

address the complexities of this issue. For information on the $1.7

billion annual U.S. Global Climate Research Program and Climate

Change Research Initiative, please find Our Changing Planet: The

Fiscal Year 2003 U.S. Global Climate Research Program (November

2002) at www.usgcrp.gov and the Draft Ten-Year Strategic Plan for the

Climate Change Science Program at www.climatescience.gov.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 1 - Cleaner Air 1.6 Challenges and Data Gaps 1-39

1.6 Challenges and Data

Gaps

Outdoor Air Quality and Acid Deposition 

In general, some very good indicators of outdoor air quality exist.

The national air monitoring network for the six criteria air pollutants

is extensive; however, there are far more monitors in urban areas than

in rural areas. Monitoring in urban areas helps to characterize population exposures, because population tends to be concentrated in

urban areas. More rural monitoring might help scientists assess

transport and ecological effects, although EPA uses additional tools

and techniques (e.g., models and spatial analyses) to augment limited monitoring in some areas and to better characterize pressures on

ecological condition. EPA is currently conducting a national assessment of the existing ambient monitoring networks and is analyzing,

among other issues, the need for and appropriateness of each of the

nation’s urban monitors. 

Many major metropolitan areas monitor air quality for the presence

of selected air toxics. However, there is no national monitoring network with standard data collection guidance for air toxics; therefore,

numerous air toxics are not being measured. National assessments of

levels of air toxics would benefit from a more extensive ambient 

monitoring network for toxics. EPA is currently working with state

and local partners to design and deploy such a network. 

Questions still exist about how indicators of concentrations and

emissions relate to exposure and human health effects. The use of

one approach to determining how various air pollution levels affect

health would be to use established and quantified effects and 

surrogates for air pollution health impacts from epidemiology studies, such as asthma hospitalizations and childhood school absences.

Research needs to be conducted that will develop these health 

endpoints into useful indicators. 

As highlighted in Chapter 4, Human Health, for most health outcomes other than mortality, no national systems for data collection

currently exist. With regard to criteria air pollutants, it would be useful to track asthma and chronic respiratory diseases, cardiovascular

diseases, and adverse birth outcomes. For air pollutants in general,

including air toxics and indoor pollutants, the list can also include

neurological diseases, developmental disabilities, reproductive 

disorders, and endocrine/metabolic disorders. 

As described in Chapter 5, Ecological Condition, there are large

gaps in our ability to report on the condition of ecological systems

and linkages between indicators of atmospheric stressors and

specific ecological effects. There is a need for improved monitoring

information for deposition and concentrations of both criteria and

toxic air pollutants to ecosystems. Data on exposure of high-elevation forests and their watersheds to ozone and acid deposition are

especially sparse, relative to data on lower elevations. And exposure

patterns are likely to be significantly different at higher elevations

because of higher acid deposition rates due to higher rainfall and

fog, and less diurnal variation in ozone concentrations due to less

nighttime scavenging (NAPAP, 1991). Furthermore, despite considerable progress, there is still no index of ozone exposure that

relates optimally to plant response (EPA, NCEA, July 1996).

Although mercury monitoring has begun as part of the National

Atmospheric Deposition Program, the availability of data is 

inadequate to assess national trends (EPA, OAQPS, ORD, December

1997). There are inadequate data on indicators of actual UV 

exposures of ecosystems of all types. 

Indoor Air Quality

While environmental indicators have been developed for some

aspects of indoor air, significant gaps exist in our knowledge about

the conditions inside the nation’s buildings. For schools and 

residences, a large amount of information on IAQ is available, but

it is composed primarily of case studies and, at best, small regional

studies. Exposure studies on a national scale would help better

characterize IAQ of schools and residential indoor environments,

including multiple family residences. Ideally, these studies would

collect exposure data on air toxics and PM in these indoor 

environments, and data for the various biological contaminants

found in indoor air.

Stratospheric Ozone

In general, high quality data exists with which to predict the human

health effects of increased ultraviolet exposure resulting from

depletion of the stratospheric ozone. These include robust satellite

data on stratospheric ozone concentrations and UV-B levels, comprehensive and well documented incidence and mortality rates for

cutaneous melanoma, and well characterized action spectra for skin

cancers and cataracts. However, there are areas where additional

data would be useful. First, no national system exists that collects

incidence data for squamous cell carcinoma and basal cell carcinoma, the non-melanoma skin-cancers caused by increased UV-B

exposure. Thus, our incidence estimates are modeled using data

from a nation-wide survey of non-melanoma skin cancer incidence

and mortality, and may not represent the most current nonmelanoma skin cancer rates. Second, there is a lack of adequate
EPA’s Draft Report on the Environment 2003 ■ Technical Document

1-40 1.6 Challenges and Data Gaps Chapter 1 - Cleaner Air

ground level UV monitoring with which to compare the satellite

data. Satellites cannot directly measure ground level UV, and are

sensitive to pollution. Therefore, while satellite data compare fairly

well to ground level UV measurements in clean locations, this is not

the case in polluted areas. Additional UV monitoring in cities is

crucial to support future epidemiological research on the human

health effects of UV-B exposure. Third, increased UV-B levels have

been associated with other human and non-human endpoints

including immune suppression and effects on aquatic ecosystems

and agricultural crops. However, additional research on these topics is necessary before these effects can be modelled or quantified.

Finally, the future behavior of the ozone layer will be affected by

changing atmospheric abundances of various atmospheric gases. 

It remains unclear how these changes will affect the predicted

recovery of the ozone layer. Additional research on the interaction

between climate and stratospheric ozone could provide more 

accurate predictions of ozone recovery and the human health

effects resulting from ozone depletion. 
Chapter 2:

Purer Water
Indicators that were selected and included in this chapter were assigned to one of two categories:

Q Category 1 –The indicator has been peer reviewed and is supported by national level data coverage for more than one time period.

The supporting data are comparable across the nation and are characterized by sound collection methodologies, data management

systems, and quality assurance procedures.

Q Category 2 –The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multi-state

regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of the

indicator have been measured (e.g., data has been collected for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by sound collection methodologies, data management systems, and

quality assurance procedures.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.0 Introduction 2-3

2.0 Introduction

Our nation’s water resources have immeasurable value. Animals,

plants, and ecosystems depend on clean and abundant water,

without which they could not exist. Humans, too, need clean water

to drink, to grow food, and to produce goods and services. Clean

water generates billions of dollars for the economy each year. Water

resources provide opportunities for families to swim and fish, and

wetlands protect homes and property against floods. Rivers, lakes,

wetlands, and coastal waters provide critical habitats for many

species and serve as nurseries for many of the valued commercial

and recreational fisheries. Water beneath the water table in fully

saturated soils and geological formations, known as ground water,

provides half the nation with drinking water. 

An increasing tide of pressures has compromised the health of many

waterbodies. In the early 20th century, industrial growth and an

expanding population left behind a legacy of pollution. After the

burning of Ohio’s Cuyahoga River—so polluted with oil and debris

that it caught fire—Congress passed the landmark Clean Water Act

(CWA) and Safe Drinking Water Act (SDWA). These acts and other

laws brought to bear strong regulatory and financial tools to clean

up polluted surface waters and ensure that public water systems

provide safe drinking water. 

Thanks to these significant investments, pollutant discharges into our

nation’s waters have been substantially reduced and the safety of public

water supplies has improved (EPA, OW, December 1999). Nevertheless,

significant water pollution problems persist and threats to drinking

water remain. Today, discharges from industry and sewage treatment

plants, together with pollution from many other sources—including,

agricultural lands, residential areas, city streets, forestry operations, and

pollutants settling out of the air—continue to degrade our nation’s

waters. Other stresses also threaten water quality. These include

landscape modification, introduction of invasive species, changes in flow

patterns, and over-harvesting of fish and other aquatic organisms.

Adequately maintained water infrastructure will be essential to

sustain the water quality gains of the past 30 years and to address

challenges to water quality and delivery of safe drinking water in the

coming years. By achieving a better understanding of the condition

of our nation’s waters, we will be able to make informed decisions

about how to protect and preserve our water infrastructure. 

This chapter summarizes what is generally understood about the 

current status and trends in water quality, the pressures affecting

water quality, and information regarding associated human health

and ecological effects. It poses fundamental questions about water

quality, sources of pollution, and health and ecological effects, and it

uses indicators drawn from well-reviewed data sources to help answer

those questions. Exhibit 2-1 lists these questions and indicators, as

well as the number of the chapter section where each indicator is

presented.

The questions addressed in this chapter are divided into four 

categories: 

Q Waters and watersheds, discussed in Section 2.2.

Q Drinking water, discussed in Section 2.3.

Q Recreation in and on the water, discussed in Section 2.4.

Q Consumption of fish and shellfish, discussed in Section 2.5.

Section 2.1 provides information on the extent and use of our

nation’s water resources. Section 2.6 reviews the challenges and data

gaps that remain in assessing the condition of our nation’s water

resources. 

The key sources of data used to support these indicators vary and

are described in each section. Some of the primary data sources that

contribute directly or indirectly to indicators throughout this chapter

include data from EPA and other federal agencies. Predominant EPA

programs or data sets supporting the indicators in this chapter

include the Environmental Monitoring and Assessment Program

(EMAP); the National Sediment Quality Inventory; the Toxics Release

Inventory (TRI); the Safe Drinking Water Information System

(SDWIS); the National Health Protection Survey of Beaches; and the

National Listing of Fish and Wildlife Advisories (NLFWA). Other

national programs that provide data for the indicators described in

this chapter include the:

Q U.S. Geological Survey’s National Water Quality Assessment

(NAWQA) program.

Q U.S. Fish and Wildlife Service’s (USFWS’s) National Wetlands

Inventory (NWI) studies of the status and trends of wetlands

resources.

Q U.S. Department of Agriculture (USDA) Natural Resources

Conservation Service’s (NRCS’s) National Resources Inventory

(NRI).

Q National Atmospheric Deposition Program (NADP).

Q National Oceanic and Atmospheric Administration (NOAA) programs.

Many of these data sets have been compiled and summarized in a

report titled The State of the Nation’s Ecosystems, developed by the 

H. John Heinz III Center for Science, Economics and the Environment

(The Heinz Center, 2002). Gaps in the data exist that make it

difficult or impossible to answer some of the questions posed about

the condition of our nation’s waters. Data gaps and limitations are

described under each question and at the end of this chapter. 
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-4 2.0 Introduction Chapter 2 - Purer Water

Question Indicator Name Category

Altered fresh water ecosystems 2

Lake Trophic State Index 2

Wetland extent and change 1

Sources of wetland change/loss 2

Water clarity in coastal waters 2

Dissolved oxygen in coastal waters 2

Total organic carbon in sediments 2

Chlorophyll concentrations 2

Percent urban land cover in riparian areas 2

Agricultural lands in riparian areas 2

Population density in coastal areas 2

Changing stream flows 1

2

Sedimentation index 2

Atmospheric deposition of nitrogen 2

2

Total nitrogen in coastal waters 2

Phosphorus in farmland, forested, and urban streams 2

Phosphorus in large rivers 2

Total phosphorus in coastal waters 2

Atmospheric deposition of mercury 2

Chemical contamination in streams and ground water 2

Pesticides in farmland streams and ground water 2

Acid sensitivity in lakes and streams 2

Sediment contamination of inland waters 2

Sediment contamination of coastal waters 2

Sediment toxicity in estuaries 2

What ecological effects are associated 

with impaired waters?

Fish Index of Biotic Integrity in streams

 Also see Ecological Condition chapter

What is the condition of coastal waters?

What is the condition of fresh surface waters and 

watersheds in the U.S.?

What are the extent and condition of wetlands?

What are pressures to water quality?

 

Exhibit 2-1: Water - Questions and Indicators

Waters and Watersheds

Section

Nitrate in farmland, forested, and urban streams and

Number/duration of dry stream flow periods in

 grassland/shrublands

ground water

Toxic releases to water of mercury, dioxin, lead, PCBs,

 and PBTs

2.2.1

2.2.1

2.2.2

2.2.2

2.2.3

2.2.3

2.2.3

2.2.3

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2

2 2.2.5

Macroinvertebrate Biotic Integrity index for streams

 Also see Ecological Condition chapter

2 2.2.5

Benthic Community Index for coastal waters

 Also see Ecological Condition chapter

2 2.2.5

General pressures

Nutrient pressures

Chemical Pressures
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.0 Introduction 2-5

Question Indicator Name Category

What is the quality of drinking water? Population served by community water systems 

that meets all health-based standards 1

What are sources of drinking water contamination? No Category 1 or 2 indicators identified

What human health effects are associated with drinking 

 contaminated water?

No Category 1 or 2 indicators identified 

Also see Human Health chapter

Question Indicator Name Category

What is the condition of waters supporting 

recreational use? Number of beach days that beaches are closed or 

under advisory

2

What are sources of recreational water pollution? No Category 1 or 2 indicators identified

What human health effects are associated with recreation in 

contaminated waters?

No Category 1 or 2 indicators identified 

Also see Human Health chapter

Question Indicator Name Category

Contaminants in fresh water fish 2

Percent of river miles and lake acres under fish 

consumption advisories

2

Number of watersheds exceeding health-based 

national water quality criteria for mercury and PCBs 

in fish tissue

2

What are contaminants in fish and shellfish, and where 

do they originate? 

What human health effects are associated with consuming 

contaminated fish and shellfish?

No Category 1 or 2 indicators identified

Also see Human Health chapter

What is the condition of waters that support consumption 

of fish and shellfish?

Drinking Water

Recreation in and on the Water

Consumption of Fish and Shellfish 

Section

Section

Section

No Category 1 or 2 indicators identified

2.3.1

2.4.1

2.5.1

2.5.1

2.5.1

2.5.2

2.5.3

2.4.2

2.4.3

2.3.2

2.3.3
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-6 2.1 Extent and Use of Water Resources Chapter 2 - Purer Water

2.1 Extent and Use of

Water Resources

Our nation’s water resources, which consist of both surface waters

and ground water, are critical to both human activities and the

functioning of ecological systems:

Q Surface waters, such as rivers, lakes, ponds, reservoirs, wetlands,

riparian (river and stream) areas, and estuarine areas, are

fundamental components of ecological systems described in this

report. They are also important sources of fresh water for human

use, including drinking water, recreation, wastewater treatment,

industrial usage, livestock, and irrigation. Wetlands and riparian

areas help provide clean water, reduce flooding, and support

critical fish and wildlife habitat. 

Q Ground water, one of our nation’s most important natural

resources, provides about 40 percent of the U.S. public water

supply and much of the rural water supply, which comes primarily

from domestic wells. Ground water also is the source of much of

the water used for irrigation, is the principal reserve of fresh water,

and represents much of our nation’s potential future water supply.

Ground water may contribute as much as 40 percent of all stream

flow in the eastern U.S. (Alley, et al., 1999).

Ground water and surface water are closely related and, in many

areas, constitute a singe resource. Both are recharged through

precipitation. The U.S. receives enough annual precipitation to cover

the entire country to a depth of 30 inches (known as the U.S. water

budget), though the eastern U.S. receives more rainfall than the

western part of the country. Over two-thirds (21 inches) of this

precipitation returns to the water cycle through evapotranspiration.

The rest becomes surface water, ground water, or soil moisture. 

Water use is an important dynamic that can impact both the

quantity and quality of available fresh water resources. Accurate

information about water use helps planners and managers make

informed decisions about our nation’s water resources. With this

information, they can project future water demand and better assess

the effectiveness of alternative water-management policies,

regulations, and conservation activities.

States report their water use to the U.S. Geological Survey (USGS) in

five mutually exclusive categories:

Q Public water supply use—water withdrawn by public and private 

water suppliers and delivered to homes and businesses for drinking,

commercial, and industrial uses. 

Q Self-supplied water—water for domestic use and for livestock that is

not drawn from the public supply. 

Q Irrigation—this includes application to crops, pastures, and recreational lands such as parks and golf courses. 

Q Thermoelectric use—that is, water used for cooling during electric

power generation. 

Q Industrial use—this includes self-supplied water for fabrication, processing, cooling, and washing (including commercial and mining uses).

The USGS coordinates the national water-use compilation effort and

publishes the results every five years in the circular series Estimated

Use of Water in the U.S. Withdrawals are reported in billions of

gallons of water per day for the five use categories. Sources of

information and accuracy of water-use data vary by state and by

water-use category (The Heinz Center, 2002). 

The USGS (Solley, et al., 1998) estimated that:

Q Total withdrawals of fresh water and saline water during 1995 were

402,000 million gallons per day (Mgal/d) for all water-use

categories (public supply, domestic, commercial, irrigation,

livestock, industrial, mining, and thermoelectric power).

Q Total fresh water withdrawals were an estimated 341,000 Mgal/d.

About 100,000 Mgal/d (29.3 percent) of this was consumed,

and the rest (241,000 Mgal/d, or 70.7 percent) was returned.

From 1960 to 1980, total water use, as well as the water use for

each major use category, increased. However, from 1980 to 1995,

total water use, as well as usage in several individual categories

declined, though water used for public supply continued to grow

(Exhibit 2-2). The two largest uses of water in the U.S.—irrigation

and cooling (during electric power generation)—were responsible

for much of the decline in total use between 1980 and 1995.

Extent of Ground Water and

Fresh Water Resources

Ground water comprises about 25 percent of all fresh water

on Earth. By contrast, surface water and soil moisture constitute less than one percent of the world's fresh water (Alley, et

al., 1999) (the remaining 75 percent is stored in polar ice and

glaciers). The Great Lakes, which cover 60.2 million acres,

hold about 18 percent of the globe's fresh surface water

(Environment Canada and EPA, 1995). 

The lower 48 states (conterminous U.S.) contain:

Q About half of our nation's 41.6 million acres of lakes,

ponds, and reservoirs.

Q About 3.7 million miles of streams and rivers (EPA, OW, June

2000).

Q An estimated 105.5 million acres of wetlands as of the mid1990s (Dahl, 2000).

Alaska has an estimated 170 million acres of wetlands, which

cover approximately 45 percent of the state. Hawaii has nearly

52,000 acres of wetlands (Dahl, 1990). U.S. coastal waters

include 66,645 miles of coastline and 57.9 million acres of

estuarine surface area (EPA, OW, June 2000).
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.1 Extent and Use of Water Resources 2-7

Decreases in withdrawals by self-supplied industrial users also contributed to the overall decline.

In many areas of the U.S., withdrawal of ground water has

significantly depleted ground water reserves. Since ground water and

surface water are closely related, this depletion can reduce river

flows, lower lake levels, and reduce discharges to wetlands and

springs. These reductions may, in turn, affect drinking water supplies,

riparian areas, and critical aquatic habitats (Alley, et al., 1999). In

the southwestern U.S., for example, the High Plains aquifer covers

174,000 square miles under eight states stretching from South

Dakota to Texas. By 1999, an estimated 220 million acre-feet (270

cubic kilometers, or something over half the amount of water

contained in Lake Erie) had been removed (USGS, 2002), primarily

for irrigation. 

Exhibit 2-2: Sources of fresh water withdrawals, 1960-1995

1960 1965 1970

Source of Freshwater 

Withdrawals

1975 1980 1985 1990 1995

Billions of gallons per day

400

350

300

250

200

150

100

50

0

1960 1965 1970

Freshwater Withdrawals

1975 1980 1985 1990 1995

Billions of gallons per day

400

350

300

250

200

150

100

50

0

Industrial

Thermoelectric

Rural

Public Supplies

Irrigation

Ground Water

Surface Water

Coverage: all 50 states

Source: Solley et al. Estimated Use of Water in the United States in 1995. 1998.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-8 2.2 Waters and Watersheds Chapter 2 - Purer Water

2.2 Waters and

Watersheds

A watershed is the area that drains to a common waterway, such as a

stream, lake, estuary, wetland, or ultimately the ocean. It is a land

feature that is identified by tracing a line along the highest elevations

(often a ridge) between two areas on a map. Watersheds come in all

shapes and sizes, and smaller watersheds drain into larger watersheds

which may cross county, state, and national boundaries. For example, a

small stream running through a farmer’s field in Pennsylvania may drain

only a few acres within the larger Susquehanna River watershed, which in

turn is a portion of the Chesapeake Bay watershed, which extends

across six states and the District of Columbia. The watershed’s natural

processes (e.g., rainfall runoff, ground water recharge, sediment

transport, plant succession) provide beneficial services when functioning

properly, but may cause ecological and physical (flooding) disasters

when misunderstood and disrupted. Watersheds are subject to many

different pressures (or “stressors”), including pollution and human

activities (see Exhibit 2-3). 

Because of their many influences on water quality, watersheds are

often the focus of efforts to manage water use and reduce pollution.

Traditionally, managers have focused on reducing pollution from

specific sources (such as sewage discharges) or within specific water

resources (such as river segments or wetlands). This approach

successfully reduces pollutant loads, but often does not adequately

address the combined concentration of multiple sources that

contribute to a watershed’s decline. For example, pollution from a

sewage treatment plant might be reduced significantly after a new

technology is installed, and yet the local river may still suffer if other

factors in the watershed, such as habitat destruction or non-point

source pollution, are not addressed. Watershed management can

offer a stronger foundation than more traditional segmented

approaches for elucidating the many stressors that affect a

watershed and for developing effective management strategies to

protect water resources. 

Section 2.2 addresses five questions about our nation’s waters and

watersheds:

Q What is the condition of fresh surface waters and watersheds in

the U.S.?

Q What are the extent and condition of wetlands?

Q What is the condition of coastal waters?

Q What are pressures to water quality?

Q What ecological affects are associated with impaired waters?

Loss of wetlands and the diversion of stream flows are important to

understand and quantify condition. Condition, which is addressed in

the first three questions, is a function of the quality, extent, and

location of the water and how that water quality affects the

condition of the biotic resources that depend on that water. To

answer questions about condition, a watershed’s extent, as well as its

chemical, physical, and biological attributes, must be defined. Section

2.2 addresses extent and chemical and physical attributes. Chapter

5, Ecological Condition, describes the biotic condition of waters and

watersheds.

2.2.1 What is the condition of

fresh surface waters and

watersheds in the U.S.? 

Because the components of condition vary naturally, condition is

most often defined as a trend in concentrations or as concentrations

relative to standards adopted by state agencies or set by EPA. Only a

few programs collect information on the condition of waters at a

national scale. One of the most widespread among these programs is

EPA’s state data collection and reporting program, mandated under

Section 305(b) of the Clean Water Act (CWA), and the associated

biennial National Water Quality Inventory (NWQI). At this time,

however, these data cannot be used to produce a national indicator

that can answer this question with sufficient confidence and

scientific credibility because the programs vary greatly from state to

state in the:

Q Percentage of waters assessed.

Q Monitoring approaches used.

Urban and suburban activities

Agricultural 

practices 

Air deposition

Forestry 

practices

Industrial 

activities

Exhibit 2-3: Selected activities affecting water, watersheds and drinking water resources Indicators

Altered fresh water ecosystems

Lake Trophic State Index
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-9

Q Water quality standards upon which the assessments are based.

Q Water quality characteristics measured in those assessments.

The CWA vests responsibility in states, territories, and tribes to assess

the health of their waters at least every two years. The purpose of these

assessments is to determine if the water quality in different areas is

supporting “designated uses,” which are defined under state procedures

and approved by EPA. Typical state designated uses include aquatic life

protection, drinking water supplies, fish and shellfish consumption,

recreation, and agricultural, industrial, and domestic uses. Because of

the high cost of monitoring, states, territories, and tribes typically

collect data and information for only a portion of their waterbodies.

Their programs and sampling techniques differ. Compounding these

differences is the fact that states also have the responsibility to set

water quality standards, many of which differ between states. States

monitor water quality to identify and address problems, and they often

place a higher priority on immediate management concerns than on

characterizing all their water resources. These issues limit the ability to

use CWA-mandated state data to describe water quality conditions at

the national level. 

Two indicators, “altered fresh water ecosystems” and “lake trophic

state,” partially address the question of the quality of the nation’s

waters. These indicators are somewhat limited at this time, but they

do show that 23 percent of fresh water resources have been altered

physically to some degree and that 22 percent of northeastern U.S.

lakes exhibit eutrophic conditions.

In addition to the CWA 305(b) reporting program, several other existing programs also contribute to our understanding of the condition of

aquatic resources:

The U.S. Geological Survey’s (USGS’s) National Water Quality

Assessment (NAWQA) program is a perennial program designed to

provide consistent descriptions of the status and trends of some of

the largest and most important streams and aquifer systems of the

nation and to link the status and trends to the natural and human

factors that affect water quality. The program involves physical,

chemical, and biological assessments of 42 large hydrologic systems,

which are conducted on staggered 10-year cycles. These

assessments include targeted sampling designs to measure stream

flow, habitat, water, sediment, and tissue chemistry, and to

characterize algae, invertebrate, and fish communities. NAWQA

studies cover watersheds and aquifers contributing a high

percentage of the water used in the U.S. The NAWQA program has

made valuable contributions in documenting the close relationship

between land use, chemicals used in watersheds (e.g., for

urban/industrial or agricultural activities), and the presence and

concentrations of chemicals found in streams and ground water.

EPA’s Environmental Monitoring and Assessment Program (EMAP)

conducts representative sampling of estuarine and stream resources

and incorporates biological measures in condition estimates.

Geographic coverage for fresh water resources is limited to the 

mid-Atlantic region and the western states. Coverage of estuarine

resources has been primarily limited to coastal areas on the East

Coast south of Cape Cod, in the Gulf of Mexico, and in some 

western states. EMAP data on biological condition have been reported for fish and macroinvertebrates in Mid-Atlantic Highland streams

and for macrobenthos in East Coast and Gulf of Mexico estuaries. 

The National Oceanic and Atmospheric Administration’s (NOAA’s)

National Status and Trends program (NS&T) collects information

on the chemical contamination of sediments and organisms and

potential biological effects in the nation’s coastal areas. Sampling of

sediments and bivalves was initiated in the mid-1980s from over 250

sites along the U.S. coast in areas not considered to be heavily polluted. On a national scale, the higher levels of contamination in sediments are clearly associated with the urbanized areas of the northeast states and with areas near San Diego, Los Angeles, and Seattle

on the West Coast. Except at a few sites, higher levels of sediment

contamination are relatively rare in the Southeast and along the Gulf

of Mexico coast.

The Natural Resources Conservation Service’s (NRCS’s) National

Resources Inventory (NRI) is a statistically-based sample of land use

and natural resource conditions and trends on U.S. non-federal

lands. NRI collects data on land cover and use, soil erosion, prime

farmland soils, wetlands, habitat diversity, selected conservation

practices, and related resource attributes. Many of the resource

inventories have recognized relationships to water quality. The NRI

provides comprehensive data on land use on the 1.5 billion acres of

non-federal lands which are made up of roughly equal parts of

rangeland (27 percent), forest land (27 percent), and cropland 

(25 percent). 

The U.S. Fish and Wildlife Service’s (USFWS’s) National

Wetlands Inventory (NWI) project produces information on the

characteristics and extent of the nation’s wetlands that is used by

the USFWS to produce status and trends reports. The Emergency

Wetlands Resources Act requires USFWS to update this information

at 10-year intervals. Data collected from over 4,300 randomly

selected sample plots provide important long-term trend information

about specific changes in wetland extent, where those changes take

place, and the overall status of wetlands in the U.S.. Data are

produced by the USFWS National Wetlands Inventory, which has

mapped 89 percent of the conterminous U.S. USFWS results are

discussed further in Section 2.2.2 of this chapter. 

These programs portray a general picture of widespread fresh water

and coastal wetland loss, of water quality widely impacted by stream

bank habitat loss, and of chemical contamination as urban land uses

and agriculture encroach into riparian areas. They show that the abundance of nutrients from agriculture and atmospheric sources impacts

coastal areas, with 40 percent of estuaries exhibiting eutrophic conditions (high nutrient concentrations and algae production), and some

estuaries also experiencing hypoxia (insufficient oxygen levels to support marine life) and reduced water clarity.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-10 2.2 Waters and Watersheds Chapter 2 - Purer Water

Pesticides from agricultural and urban areas are found widely in

surface waters, and residues from past chemical uses are found in

sediments and fish tissue. Mercury and mercury compounds are

foremost among pollutants contaminating fish. Bacterial

contamination is found throughout surface waters used for drinking,

although treatment of public water supplies is an effective barrier to

protect human health. Contamination of swimming beaches by

bacteria, however, continues to be a concern. 

An improved ability to report on the condition of surface waters will

require a collaboration of states, tribal authorities, and federal

agencies. This may involve a nationally coordinated program. Under

Section 305(b) of the Clean Water Act, states are required to report

on the condition of their waterways. This requirement could serve as

a platform upon which national condition estimates could be

compiled using a consistent sample design approach and comparable

data collection and analysis procedures.

EPA has long sought to increase the coverage of water quality

assessments made and submitted biannually in conformance with

Section 305(b) of the CWA. Historically, states have employed

monitoring programs with sampling methods targeted to known

problem areas that exhibit well-defined point and non-point

pollution sources. While these approaches are effective in relating

pollution sources to water quality conditions, they cannot accurately

represent both the extent and condition of water quality problems

and resources. EPA issued guidance on water quality assessments in

1997 (EPA, OW, September 1997), and produced a major

supplement to this guidance in 2002 (EPA, OW, July 2002). These

documents describe a comprehensive assessment as an evaluation of

water resources that covers a complete geographic area or resource;

provides information on the resource condition and spatial and

temporal trends in the resource condition; and identifies the

stressors (causes) and sources of pollution. The approach to these

assessments is defined as either a complete survey (census), a

judgmental or targeted design, or a statistical survey (probabilitybased) using randomly selected sample locations that allow

researchers to make valid inferences about the condition of the water

resource. The targeted approach is effective for relating specific

pollution sources to water condition and is used in guiding pollution

abatement, whereas the statistical/census survey approaches provide

a complete or representative assessment of the entire resource. 

In 2000, 14 states reported that they had monitored and assessed

more than 95 percent of their lakes, and 10 states reported that

they had assessed at least 98 percent of their rivers. Two years.

later, in 2002, three states reported that they had made these

assessments using a statistically valid sampling design. Several 

states are engaged in multi-year studies that are adding probabilistic

surveys to their assessments. Examples of states that are collecting

data from statistically-based monitoring networks are described in

the sidebar. 

Statistically-based water quality 

monitoring in states: 

Two examples

Indiana

In its 2002 State of the Environment Report, the Indiana

Department of Environmental Management (IDEM) used a statistical survey to assess stream water quality by major watersheds. Historically, IDEM assessed 6,000 to 8,000 miles of

stream every two years. Beginning in 1996, 20 percent of the

state's streams were sampled each year in its watershed monitoring program and then assessed for the ability to support

aquatic life. The results allowed IDEM to estimate the water

quality within each major water basin in the state. IDEM

reports its data with 95 percent confidence. Accuracy varies

between basins, but is between 11 and 16 percent.

Of the 35,430 stream miles assessed over the past five years,

approximately 64.5 percent were estimated to fully support

the maintenance of well-balanced aquatic communities. Fish

and benthic macroinvertebrate community assessments provided a measurement of adverse response to stressors. Some of

the community responses included loss of sensitive species,

lack of diversity, and increase in tolerant species. As a result,

several hundred stream miles were classified as not fully supporting aquatic life based on the fish and macroinvertebrate

community surveyed.

Maryland

The Maryland Biological Stream Survey (MBSS) uses a probabilitybased survey design to assess the status of biological resources in

Maryland's non-tidal streams. The state intends to:

Q Characterize biological resources and ecological conditions.

Q Assess the condition of these resources.

Q Identify the likely sources of degradation.

The state has developed an interim framework for applying biocriteria in the state's water quality inventory (305[b] report) and list of

impaired waters (303[d] list). To date, the proposed biocriteria for

wadeable, non-tidal (first- to fourth-order) streams rely on two biological indicators from the MBSS; the fish and benthic indices of

biotic integrity (IBIs). The approach centers on identifying impaired

waterbodies at the Maryland 8-digit watershed and 12-digit subwatershed levels.

A preliminary evaluation using MBSS 2000 data was conducted to

identify watersheds failing to meet the requirements of the interim

biocriteria framework. For a portion of the state, three 8-digit watersheds that were assessed passed, and six were inconclusive. Of the

123 watersheds sampled at the 12-digit subwatershed level, 69

failed, 32 passed, and 22 were inconclusive.
Technical Document Q EPA’s Draft Report on the Environment 2003

Physically altering a fresh waterbody can change its character and

the benefits it provides local communities and land owners. Fresh

waterbodies may be altered to increase some other benefit— for

example, to control floods; improve navigation; reduce erosion;

increase the available area for farming, livestock grazing, or development; and increase the amount of water available for drinking

and industrial purposes. However, these alterations also change

fish and wildlife habitat, disrupt patterns and timing of waterflows,

serve as barriers to animal movement, and reduce or eliminate the

natural filtering of sediment and pollutants. In addition, water

usage, particularly in the arid West, but also in suburban areas

that rely on wells, may deplete aquifers and thus cause permanent

damage to the physical characteristics of surface water resources,

including reduced base flows.

The altered fresh water ecosystems indicator reports the

percentage of each of the major fresh water ecosystems (rivers

and streams, riparian areas, wetlands, lakes, ponds, and reservoirs)

that are altered. “Altered” is defined differently for each of these

ecosystems: 

Q Streams and rivers (all flowing surface waters) are altered if they

are leveed or channelized or impounded behind a dam.

Q Riparian zones along rivers and streams are considered altered

if they are used for urban or agricultural purposes.

Q Lakes and reservoirs are considered altered if any portion of the

area immediately adjacent to the shoreline is either urban or

agricultural land. Since there is no agreed-upon proportion of

shoreline that must be in these land use categories to classify

an individual lake as “altered,” this indicator simply reports the

overall percentage of lake or reservoir shoreline with agricultural

or urban land use in the shoreline zone. (Note that, at present,

data for lakes and reservoirs are aggregated, even though a

reservoir is a man-made structure or seriously altered habitat. If,

in the future, natural lakes can be distinguished from reservoirs,

these may be reported separately. In this case, the number or

percent of natural lakes whose waterflow has been altered by

damming would also be reported.)

Q Wetlands are considered altered if they are excavated, impounded,

diked, partially drained, or farmed (Cowardin, et al., 1979).

What the Data Show

Data reported for this indicator were produced using remote 

sensing imagery and the USGS stream/lake database (National

Hydrography Data Set). These data characterize areas adjacent to

a waterbody at a resolution of about 100 feet across. Thus, they

present the general land cover surrounding a lake or stream,

rather than a fine-scale picture of the exact composition of a

shoreline or bank. 

The available data indicate that 23 percent of the banks of both

rivers and streams (riparian areas) and lakes and reservoirs have

either croplands or urban development in the narrow area immediately adjacent to them. Data on the degree to which streams and

rivers are channelized, leveed, or impounded are not available. 

Dahl (2000) does provide some information on the extent to

which wetlands are altered. For example, from 1986 to 1997:

Q A total of 78,100 acres (31,600 hectares) of forested wetlands

were converted to fresh water ponds. 

Q Human activities, such as creating new impoundments or raising

the water levels on existing impoundments (thus killing the

trees), created conversions to deep water lakes. 

Q Additionally, fresh water unconsolidated shores exhibited an 8

percent gain in acreage or about 32,000 acres (13,000

hectares). This was due, in part, to peat mining operations that

removed the wetland vegetation and exposed the substrate.

Because these areas were not drained, they remained wetland,

but their classification was changed from “fresh water shrub

bogs” to “fresh water unconsolidated shores.”

Indicator Gaps and Limitations

There is no nationally aggregated database that records the number of impounded or leveed river miles. As noted above, there is

also no method for calculating the extent of downstream effects

of dams, other than by conducting site-specific investigations for

each dam. 

At present, there are no nationally aggregated databases that list

whether natural lakes are dammed at their outlets. It is possible

that existing databases on dam locations, such as those maintained by the U.S. Army Corps of Engineers, could be merged with

other datasets, such as the National Hydrography Data Set

(NHD), to derive this information. 

Data on the alteration of rivers and streams are not collected in a

manner that allows for aggregation to provide a national

perspective.

Data Source

Data on altered wetlands are available only in paper form on a

quad-sheet by quad-sheet basis. The data sources for this 

indicator were the:

Q Multi-Resolution Land Characterization Consortium and U.S.

Geological Survey National Hydrography Dataset, processed by

Indicator Altered fresh water ecosystems – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-11
EPA’s Draft Report on the Environment 2003 Q Technical Document

the EPA’s Office of Research and Development (National

Exposure Research Laboratory).

Q Department of the Interior, U.S. Fish and Wildlife Service,

National Wetlands Inventory (See Appendix B, page B-9, for

more information.).

Indicator Altered fresh water ecosystems – Category 2 (continued)

2-12 2.2 Waters and Watersheds Chapter 2 - Purer Water

Lakes can be divided into three categories based on trophic state:

oligotrophic, mesotrophic, and eutrophic. These categories reflect

a lake’s nutrient and clarity levels. 

Q Oligotrophic lakes are generally clear, deep, and free of weeds or

large algae blooms. They are low in nutrients and do not support large numbers of fish. Oligotrophic lakes often develop a

food chain capable of sustaining a very desirable fishery of

large game fish.

Q Eutrophic lakes are high in nutrients and support a large biomass

(all the plants and animals living in a lake). They are usually

either weedy, or subject to frequent algae blooms, or both.

Eutrophic lakes often support large fish populations, but are

also susceptible to oxygen depletion. A subcategory, hypertrophic lakes, is used below to describe lakes that are extremely

eutrophic (i.e., very nutrient-enriched), resulting in particularly

high productivity (Peterson, et al., 1999). 

Q Mesotrophic lakes lie between the oligotrophic and eutrophic

stages. 

A natural aging process occurs in all lakes, causing them to change

from oligotrophic to eutrophic over time. This process is accelerated by nutrient enrichment from agriculture, lawn fertilizers,

streets, septic systems, and urban storm drains.

Various methods are used to calculate the trophic state of lakes.

Common characteristics used to determine trophic state are: total

phosphorus concentration (important for algae growth); concentration of chlorophyll a (a measure of the amount of algae present); and secchi disc readings (an indicator of water clarity).

No national data regarding the trophic state of lakes are available.

However, regional patterns of lake trophic condition were assessed

for a target population of 11,076 northeast lakes, which were

sampled during the summers of 1991 to 1994 using a trophic

state index based primarily on their nutrient or total phosphorus

(TP) concentrations (Peterson, et al., 1999). A total of 344 lakes

were sampled once.

The following trophic state categories were established based on

total phosphorus concentrations:

Q Oligotrophic for nutrient poor (less than 10 parts per 

billion [ppb]).

Q Mesotrophic to denote nutrient concentrations sufficient to 

support natural algal communities (from 10 to 30 ppb).

Q Eutrophic for enriched nutrient conditions (from 30 to 60 ppb).

Q Hypertrophic for very nutrient-enriched (greater than 60 ppb).

What the Data Show

The trophic state analysis (Exhibit 2-4) showed that 37.9 percent

of the northeast lakes were oligotrophic, 40.1 percent were

mesotrophic, 12.6 percent were eutrophic, and 9.3 percent were

hypertrophic (Peterson, et al., 1999).

Indicator Lake Trophic State Index – Category 2 

Oligotrophic

37.9%

Mesotrophic

40.1%

Eutrophic

12.6%

Hypertrophic

9.3%

Source: Peterson S.A., et al. Sample Representativeness: A Must for Reliable 

Regional Lake Condition Estimates. 1999.

Exhibit 2-4: Trophic State Index for northeast lakes,

1991-1994
Technical Document Q EPA’s Draft Report on the Environment 2003

Indicator Gaps and Limitations

These data reflect a one-time sample of lakes in one region, the

Northeast, and cannot be extrapolated to the national scale or

provide trends data. Also, trophic status in and of itself does not

necessarily imply that water quality problems exist (i.e., that oligotrophy is a common natural state). 

Data Source

The data source for this indicator was the Environmental

Monitoring and Assessment Program Lakes Data Set. (See

Appendix B, page B-9, for more information.)

Indicator Lake Trophic State Index – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-13

2.2.2 What are the extent and

condition of wetlands?

When European settlers first arrived, wetland acreage in the area that

would become the 48 states was more than 220 million acres, or about

five percent of the total area of the conterminous U.S. More than onehalf of the wetlands in the conterminous U.S. have been lost or converted to other uses since pre-colonial times. However, in as little as four

recent decades, the rate of wetland loss has declined dramatically, from

about 500,000 acres per year to less than 100,000 acres per year

(Dahl, 2000). By 1997, total wetland acreage was estimated to be

105.5 million acres (Dahl, 2000). Almost 50 percent of wetland loss

occurring in the 1990s was due to conversion to urban and suburban

development. 

Wetland ecosystems are areas that are inundated or saturated by

surface or ground water at a frequency and duration sufficient to

support (and that under normal circumstances do support) a

prevalence of vegetation typically adapted for life in saturated soil

conditions. There are different types of wetlands, including: fresh water

wetlands, inland wetlands, and coastal wetlands (see glossary for

definitions). These habitats provide many benefits to humans and

ecological systems. For example, wetland habitats are critical to the life

cycles of many plants and fish, shellfish, migratory birds, and other

wildlife. They provide essential breeding habitat for roughly onequarter of all North American breeding bird species (Davis, 2000). In

1997, it was estimated that 81 percent (72 species) of the U.S. bird

species on the Endangered Species List were dependent on or

associated with wetlands (Day Boylan and MacLean, 1997).

An estimated 95 percent of commercial fish and 85 percent of sport

fish spend a portion of their life cycles in coastal wetland and estuarine habitats. Adult stocks of commercially harvested shrimp, blue

crab, oysters, and many other species throughout the U.S. (EPA,

ORD, OW, September 2001) are directly related to wetland quality

and quantity (EPA, OW, OWOW, March 2002). More than half of all

U.S. adults (98 million people) hunt, fish, birdwatch, or photograph

wildlife (USFWS, 2002). Many of these activities are associated with

healthy wetlands.

Wetlands also filter residential, agricultural, and industrial wastes,

thereby improving surface water quality. They buffer coastal areas

against storm and wave damage. Wetlands function as natural

sponges that trap and slowly release surface water, rain, snowmelt,

ground water, and flood waters. Trees, root mats, and other wetland

vegetation also slow the speed of flood waters and distribute them

more slowly over the floodplain. This combined water storage and

braking action lowers flood heights and reduces erosion. Wetlands

within and downstream of urban areas are particularly valuable,

counteracting the greatly increased rate and volume of surface water

runoff from pavement and buildings. The holding capacity of wetlands helps control floods and prevents water logging of crops.

Preserving and restoring wetlands can often provide the level of

flood control otherwise provided by expensive dredge operations

and levees. For example, the bottomland hardwood-riparian wetlands

along the Mississippi River once stored at least 60 days of flood

water. Now these wetlands store only 12 days of flood water because

most have been filled or drained (EPA, OW, December 1995).

Wetlands are diverse. Inland wetlands are most common on floodplains along rivers and streams (riparian wetlands), in isolated

depressions surrounded by dry land (e.g., playas, basins, and “potholes”), along the margins of lakes and ponds, and in other low-lying

areas where the ground water intercepts the soil surface or where

precipitation sufficiently saturates the soil (e.g., vernal pools and

bogs). Inland wetlands include marshes and wet meadows dominated

by herbaceous plants, swamps dominated by shrubs, and wooded

swamps dominated by trees. Many wetlands are seasonal (i.e., they

are dry one or more seasons every year). In fact, particularly in the

arid and semiarid West, wetlands may be wet only periodically. The

quantity of water present and the timing of its presence in part

determine the functions of a wetland and its role in the environment.

Even wetlands that appear dry at times for significant parts of the

Indicators

Wetland extent and change

Sources of wetland change/loss
EPA’s Draft Report on the Environment 2003 Q Technical Document

Two programs, the USFWS NWI status and trends studies and the

NRCS NRI, estimate wetland extent. The USFWS surveys all

wetlands in the conterminous U.S. The NRI surveys wetlands on

non-federal lands, which make up approximately 75 percent of the

nation’s land base. The methods employed differ, but the

statistical results from the most recent survey period were not

significantly different. USFWS data are used for the “wetland

extent and change” indicator due to their broader coverage. This

indicator is derived from three separate analyses: one covering the

1950s to the 1970s; one covering the 1970s to 1980s, and one

covering the 1980s to the 1990s. 

The USFWS counts all wetlands every 10 years, regardless of land

ownership, but only recognizes wetlands that are at least three

acres. A permanent study design is used, based initially on

stratification of the 48 conterminous states by state boundaries

and 35 physiographic subdivisions. Within these subdivisions are

4,375 randomly selected, four-square-mile (2,560 acres) sample

plots. These plots were examined with the use of aerial imagery,

ranging in scale and type; most were 1:40,000 scale, color

infrared, from the National Aerial Photography Program. 

Field verification was conducted to address questions of image interpretation, land use coding, and attribution of wetland gains or losses;

plot delineations were also completed. For example, for the 1980s to

1990s analysis, 21 percent of the sample plots were verified.

What the Data Show

When European settlers first arrived, wetland acreage in the area that

would become the 48 states was more than 220 million acres, or

about five percent of the total area of the conterminous U.S. Since

then, extensive losses have occurred, and over half of our original

wetlands have been drained and filled. By 1997, total wetland acreage

was estimated to be 105.5 million acres (Dahl, 2000). Of that total,

nearly 95 percent or 100.2 million acres were fresh water and about

five percent or 5.3 million acres were intertidal marine and estuarine.

Between 1986 and 1997, 98 percent of all wetland losses in the conterminous U.S. were fresh water wetlands. 

Rates of annual wetland losses have been decreasing from almost

500,000 acres a year three decades ago to less than 100,000

acres, averaged annually since 1986 (Exhibit 2-5). The USFWS

estimated the annual rate of loss at 58,500 acres per year

between 1986 and 1997. This represents an 80 percent reduction

compared to the previous decade’s rate of loss. The slower rate of

wetland loss is due to several factors, including: 

Q Federal farm policies that discourage drainage and encourage

restoration.

Q More effective government regulation.

Q Better land stewardship.

Q Acquisition and protection of sensitive environmental areas.

Q More state, tribal, and local involvement in wetland protection

programs.

Indicator Wetland extent and change – Category 1

2-14 2.2 Waters and Watersheds Chapter 2 - Purer Water

year, such as vernal pools, often provide critical habitat for wildlife

adapted to breeding exclusively in these areas.

Coastal wetlands in the U.S. are found along the Atlantic, Pacific,

Alaskan, and Gulf coasts. They are closely linked to our nation’s

estuaries, where sea water mixes with fresh water to form an environment of varying salinities. Certain grasses and grasslike plants that

adapt to the saline conditions form the tidal salt marshes that are

found along the Atlantic, Gulf, and Pacific coasts. Mangrove swamps,

with salt-loving shrubs or trees, are common in tropical climates,

such as in southern Florida and Puerto Rico. Some tidal fresh water

wetlands form beyond the upper edges of tidal salt marshes where

the influence of salt water ends. 

An indicator related to wetland extent has been identified to address

the question “What are the extent and condition of wetlands?” This

indicator is discussed on the following pages. No indicators for the

biological condition of wetlands are being implemented nationally or

regionally at this time, and none were recommended for inclusion in

this report. However, wetland extent can partially serve as a surrogate to address wetland condition. This is because the loss of wetlands in the landscape negatively impacts the condition of the

remaining wetlands by decreasing both the connectivity among

aquatic resources and the landscape heterogenity.

Indicators of wetland condition are being developed and

implemented by some states, but not on a broad-scale basis. States

have been developing assessment methods for a variety of organisms

in multiple wetland types, including macroinvertebrates, algae,

amphibians, and vegetation (Danielson, 1998). These indicators and

an assessment process will be necessary to ensure that both wetland

extent and condition can be properly described in the future.
Technical Document Q EPA’s Draft Report on the Environment 2003

In addition to loss of wetland acreage, a major ecological impact has

been the conversion of one wetland type to another, such as clearing trees from a forested wetland or excavating a shallow marsh to

create an open water pond. Open water ponds have more than doubled in area since the 1950s and are not the ecological equivalent

of fresh water emergent marshes. These types of conversions change

habitat types and community structure in watersheds and impact

the animal communities that depend on them.

Wetland types include fresh water forested, shrub, and emergent wetlands, plus open water ponds. Forested and emergent

wetlands make up over 75 percent of all fresh water wetlands.

Since the 1950s, fresh water emergent wetlands have declined

by nearly 24 percent—more than any other fresh water wetland type. Fresh water forested wetlands have sustained the

greatest overall losses—10.4 million acres since the 1950s

(Exhibit 2-6).

Coastal wetlands are the vegetated interface between aquatic and

terrestrial components of estuarine ecosystems. Estuarine emergent wetlands account for nearly 75 percent of coastal wetlands.

The loss of coastal wetland habitats in the U.S. is significant

(Exhibit 2-7). Since the 1950s, coastal and estuarine losses were

about 1.4 million acres–a nearly 12 percent decline. Emergent

and forested intertidal wetlands experienced the greatest absolute

and proportional losses during this four-decade measurement

period. Proportional losses along the West Coast have been the

largest (68 percent), although the actual number of acres lost

there is among the smallest. Absolute and proportional acreages

lost in the Great Lakes and Gulf of Mexico are also high (about 

50 percent of wetlands that existed in pre-colonial times). Even in

more recent years (mid- to late 1990s), wetland losses in southeastern and Gulf of Mexico states continue at a high rate—more

than one percent per year. 

Indicator Wetland extent and change – Category 1 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-15

100,000

0

200,000

300,000

400,000

500,000

600,000

1954-74 1974-83 1986-97

Acres

458,000

290,000

58,500

Exhibit 2-5: Average annual wetland loss, 

1954-1974, 1974-1983, 1986-1997

Coverage: Conterminous United States

Source: Frayer et al. Status and Trends of Wetlands and Deepwater 

Habitats in the Conterminous United States, 1950s to 1970s. 1983; 

Dahl, T.E. and C. E. Johnson. Wetlands Status and Trends in the 

Conterminous United States: 1970s to 1980s. 1991; Dahl, T. E. Status 

and Trends of Wetlands in the Conterminous United States 1986 to 

1997. 2000.

A. All Intertidal Wetlands

62,000

60,000

58,000

56,000

54,000

52,000

50,000

Acres (in Thousands)

Acres (in Thousands)

Acres (in Thousands)

A. Freshwater Forested 61,150

55,151

51,930

50,729

1950s 1970s 1980s 1990s

20,000

18,000

16,000

14,000

12,000

10,000

8,000

B. Freshwater Shrubs

11,000

15,506

17,235

18,366

1950s 1970s 1980s 1990s

36,000

34,000

32,000

30,000

28,000

26,000

24,000

C. Freshwater Emergent 33,133

28,440

26,383

25,157

1950s 1970s 1980s 1990s

Coverage: Conterminous United States

Source: Frayer et al. Status and Trends of Wetlands and Deepwater Habitats in the 

Conterminous United States, 1950s to 1970s. 1983; Dahl, T.E. and C. E. Johnson. 

Wetlands Status and Trends in the Conterminous United States: 1970s to 1980s. 1991; 

Dahl, T. E. Status and Trends of Wetlands in the Conterminous United States 1986 to 

1997. 2000.

Exhibit 2-6: Long-term trends in selected 

freshwater wetlands, 1954-1997
EPA’s Draft Report on the Environment 2003 Q Technical Document

Indicator Gaps and Limitations

This indicator does not effectively address the question of wetland condition. While it is possible to inventory wetlands that

have been lost, many wetlands have suffered degradation of condition and functions, which cannot be quantified nationally.

Different methods were used in some of the early classification

schemes to classify wetland types. The currently used classification system was not applied to some of the earlier (1970s) maps.

As methods and spatial resolution have improved over time,

acreage data were adjusted, resulting in changes in the overall

wetland base over time. Thus, the evaluation process is evolving,

which contributes to reducing the accuracy of the trends

observed.

Forested wetlands are difficult to photointerpret and are generally

underestimated by the USFWS. Ephemeral wetlands and effectively

drained palustrine wetlands observed in farm production are not

recognized as a wetland type by the USFWS and, therefore, are not

included. Also, USFWS does not survey wetlands under 3 acres in

size; therefore, no record exists of the extent and change in these

valuable resources. Pacific coast estuarine wetlands are not surveyed

due to the discontinuity in their patch sizes. The temporal coverage

of the coastal wetland loss indicator (length of record) is not

consistent across the U.S.

Data Source

The data for this indicator are from the Department of the

Interior, U.S. Fish and Wildlife Service, Status and Trends Report.

(See Appendix B, page B-9 for more information.)

Indicator Wetland extent and change – Category 1 (continued)

2-16 2.2 Waters and Watersheds Chapter 2 - Purer Water

5,000

5,200

5,400

5,600

5,800

6,000

6,200

Acres (in Thousands)

B. Estuarine Vegetated Wetlands

4,200

4,400

4,600

4,800

5,000

5,200

1950s 1970s 1980s 1990s

Acres (in Thousands)

C. Estuarine Non-vegetated Wetlands

0

200

400

600

800

1,000

1950s 1970s 1980s 1990s

Acres (in Thousands)

6,000 A. All Intertidal Wetlands

5,500

5,204 5,195

1950s 1970s 1980s 1990s

4,615 4,623

4,854

5,000

580 580

678

741

Coverage: Conterminous United States

Source: Frayer et al. Status and Trends of Wetlands and Deepwater Habitats in the 

Conterminous United States, 1950s to 1970s. 1983; Dahl, T.E. and C. E. Johnson. 

Wetlands Status and Trends in the Conterminous United States: 1970s to 1980s. 1991; 

Dahl, T. E. Status and Trends of Wetlands in the Conterminous United States 1986 to 

1997. 2000.

Exhibit 2-7: Long-term trends in 

selected estuarine wetlands, 1954-1997
Technical Document Q EPA’s Draft Report on the Environment 2003

This indicator attempts to estimate the causes or sources of wetland losses. The extensive survey data collected in the NRI by the

USDA’s Natural Resources Conservation Service in cooperation

with the Iowa State University Statistical Laboratory provides land

use information that can be associated with estimates of wetland

extent. This database is a compilation of natural resource information on non-federal land, which comprises nearly 75 percent of

the nation’s total land area. The 1997 NRI captures data on land

cover and use, soil erosion, prime farmland soils, wetlands, habitat

diversity, selected conservation practices, and related resource

attributes at over 300,000 primary sample units (nominally 160

acres each) containing over 800,000 sample points.

Data used for the NRI were collected using a variety of imagery,

field office records, historical records and data, ancillary materials,

and a limited number of on-site visits. The data have been compiled, verified, and analyzed to provide a comprehensive look at

the state of the nation’s non-federal lands.

What the Data Show

According to the USDA Agricultural Research Service, between

1954 and 1974, agriculture accounted for 81 percent of all

wetlands conversions. As a result of changing federal agricultural

policies that emphasize wetlands conservation, agriculture

accounted for only 20 percent of national wetlands conversion

between 1982 and 1992 (USDA, 2000). In surveys conducted

between 1992 and 1997, NRI determined that 506,000 acres of

wetlands on non-federal lands were lost, while 343,000 were

gained, for a net loss of 163,000 acres. Agriculture accounted for

26 percent of the net national wetlands loss for this survey

period, although this varies by region. For example, in the Midwest

and northern plains, about 50 percent of the losses were from

agriculture (Exhibit 2-8). Since the mid–to late 1980s, urban,

suburban, and commercial development have been the major

contributors to net losses of wetland resources and were

responsible for 49 percent of those losses. The East, Southeast,

and South Central states had the highest percentages of wetland

losses due to development. In the East, 67 percent of the wetland

losses were a result of development (USDA, 2000). Timber

harvesting practices and conversion of land to silvicultural uses

Indicator Sources of wetland change/loss – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-17

Exhibit 2-8: Non-Federal wetland losses and gains and reasons for conversion, 1992–1997

Source: Summary Report: 1997 National Resources Inventory (Revised December 2000). 2000.

Silviculture

Development

Agriculture

Misc.

South Central

West

Northern Plains

Midwest

Southeast

East

Gain

Loss

Reasons

coverage does not include Alaska, Hawaii or Puerto Rico
EPA’s Draft Report on the Environment 2003 Q Technical Document

have also contributed to losses in wetland resources. The NRI

analysis attributed 12 percent of the wetland losses between

1992 and 1997 to silviculture. 

Using different methods, the USFWS reported a similar result from

1986 to 1997: 30 percent of wetland losses were attributed to

urban development; 21 percent to rural development; 23 percent

to silviculture; and 26 percent to agriculture (Dahl, 2000).

Indicator Gaps and Limitations 

The differences in survey design between NRI and USFWS will

continue to cause difficulties in assessing the effectiveness of

current wetlands policies. The USFWS data are gathered from

interpretation of aerial imagery and remotely sensed data, and are

repeated every 10 years. The NRI data are based on statistical

sampling, but do not include an adequate sample of coastal

resources. They provide information at a coarse scale, summarized

by state, and are useful for national reporting. The NRI does not

collect data on federal lands or for the state of Alaska. 

Data Source

Data for this indicator come from the U.S. Department of

Agriculture, National Resources Inventory (2000). 

(See Appendix B, page B-10, for more information.)

Indicator Sources of wetland change/loss – Category 2 (continued)

2-18 2.2 Waters and Watersheds Chapter 2 - Purer Water

2.2.3 What is the condition of

coastal waters?

Coastal waters—the interface between the land and the sea—

provide a wide range of habitats for animals and plants essential to

global ecosystems, and they support the majority of commercial and

recreational fisheries in the U.S. Coastal waters also contain

significant energy and mineral reserves, travel lanes for shipping, and

a base for outdoor recreation and tourism industries (EPA, ORD,

OW, September 2001).

Coastal waters include estuaries—bodies of water that are balanced

by fresh water and sediment influx from rivers and tidal action of

the oceans. They provide a transition zone between fresh water and

saline water. Estuaries are unique environments that support wildlife

and fisheries and contribute substantially to the economy of

coastal areas. These natural areas are under the most intense development pressure in the nation. This narrow fringe accounts for only

17 percent of the total conterminous U.S. land area, but is home to

more than 53 percent of the population. Today, that proportion is

growing faster than in any other area of the U.S. (NRC, 2000). 

Four indicators have been selected to address the condition of

coastal waters: water clarity, dissolved oxygen content, organic 

carbon content of sediments, and chlorophyll concentrations. The

first three—water clarity, dissolved oxygen, and organic carbon

content—are derived from EPA’s EMAP, which samples estuaries

using a probability- based design. 

For water clarity and dissolved oxygen, estuaries in the East, West,

and Gulf of Mexico coast are well represented. These two indicators,

as reported in EPA’s Coastal Condition Report (EPA, ORD, OW,

September 2001), show that water clarity and oxygen conditions are

good. Organic carbon data indicate that 16 percent of the area of

mid-Atlantic estuaries have enriched carbon levels. About 33 percent

of the mid-Atlantic estuarine area had chlorophyll concentrations

exceeding the Chesapeake Bay restoration goal for survival of 

submerged aquatic vegetation. Coastal waters overall exhibited much

lower chlorophyll concentrations. Chlorophyll concentrations were

the most pronounced in the Gulf of Mexico.

Eutrophication is also an important parameter for understanding the

condition of coastal waters; however, insufficient data were available

to develop a scientifically robust indicator for this parameter at the

national level. Eutrophication is discussed following the indicator

descriptions. 

Indicators

Water clarity in coastal waters

Dissolved oxygen in coastal waters

Total organic carbon in sediments

Chlorophyll concentrations
Technical Document Q EPA’s Draft Report on the Environment 2003

Light penetration is an important characteristic of many estuarine

and coastal habitats. Reduced penetration is often associated with

eutrophic conditions, algal blooms, and erosional events. Reduced

clarity can impair the normal algal growth that contributes to

oligotrophy and the extent and vitality of submerged aquatic

vegetation. This is a critical habitat component for many aquatic

animals.

For purposes of this indicator, water clarity is defined as a measure

of light penetration (i.e., the amount and type of light reaching a

one - meter water depth compared to the amount and type of

light at the water’s surface). Data were collected using a point-intime measurement with a transmissometer, which estimates light

transmission. Measurements were made at one meter below the

water’s surface. EPA in its Coastal Condition Report describes light

penetration less than 10 percent of the amount of light incident

at the surface is considered to represent poor conditions. Light

penetration greater than 25 percent of that at the surface is

deemed good.

What the Data Show

The overall water clarity of the nation’s estuaries is rated as good

(EPA, ORD, OW, September 2001). That is, 25 percent of light

incident at the surface penetrates to a depth of one meter. That

condition existed at 64 percent of the estuarine areas assessed.

Poor light penetration is a problem in only about four percent of

estuarine waters (Exhibit 2-9).

Indicator Gaps and Limitations

Sampling generally occurred during an EMAP-defined index period

(summer months) as a point-in- time measure. While eutrophic

stress is expected to be highest during warmer months, episodic

algal blooms or runoff/erosional events would likely not occur

during this timeframe.

Turbid waters are a natural characteristic of many estuaries 

(e.g., upper Chesapeake Bay, Albermarle-Pamlico Sound), and low

light penetration conditions are not necessarily associated with

impaired aquatic health. This indicator does not account for 

naturally turbid conditions and will rate those areas as “poor,”

reflecting degraded water quality.

Data Source

Water clarity data are from EPA’s Environmental Monitoring and

Assessment Program Estuaries database. (See Appendix B, 

page B-10, for more information.)

Indicator Water clarity in coastal waters – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-19

Exhibit 2-9: Estuarine area with good (>25% of light incident 

at the surface), fair (between 25 and 10% of incident light), and 

poor (<10% of incident light) light penetration, 1990 - 1997

4% 

<10% Poor

64% 

32%

10-25% Fair >25% Good

Coverage: United States east coast (excluding waters north of Cape Cod), 

west coast, and Gulf of Mexico

Source: EPA, Office of Research and Development and Office of Water. 

National Coastal Condition Report. September 2001.
EPA’s Draft Report on the Environment 2003 Q Technical Document

Dissolved oxygen (DO) is a fundamental requirement for all

estuarine life. Low levels of oxygen often accompany the onset of

severe bacterial degradation, sometimes resulting in algal scums,

fish kills, and noxious odors, as well as loss of habitat and

aesthetic values. Often, low dissolved oxygen occurs as a result of

the process of decay of large algal blooms whose remnants sink to

the bottom. Concentrations of oxygen below about 2 parts per

million are thought to be stressful to estuarine organisms (Diaz

and Rosenberg, 1995; EPA, OW, October 2000).

Under EPA’s EMAP, data were collected generally at one-meter

above the bottom using electronic DO meters. In some cases, data

were point-in-time measurements taken once during the summer

months (e.g., in the Virginian Province), while in other cases data

were predominantly collected by continuous readings over a multiple day/time period (e.g., in the Louisianian Province). Values of

dissolved oxygen were classified into three condition categories: 

Q Poor: less than 2 parts per million (ppm)

Q Fair: between 2 and 5 ppm

Q Good: greater than 5 ppm

What the Data Show

Dissolved oxygen conditions in the nation’s estuaries are reported

by EPA, ORD, OW (September 2001) in its Coastal Condition

Report as “good” because 80 percent of the estuarine waters

assessed exhibited dissolved oxygen at concentrations greater

than five ppm. Both EMAP and NOAA’s National Eutrophication

Assessment examined the extent of estuarine waters with low

dissolved oxygen. EMAP estimates that only about four percent of

bottom waters have low dissolved oxygen (Exhibit 2- 10).

However, low dissolved oxygen is a problem in some individual

estuarine systems like the Neuse River Estuary and parts of the

Chesapeake Bay.

Hypoxia resulting from anthropogenic activities is a relatively 

local occurrence in Gulf of Mexico estuaries, accounting for about

4 percent of the total area, however, hypoxia in the shelf waters of

the Gulf of Mexico is more significant. The Gulf of Mexico hypoxia

zone is the largest anthropogenic coastal hypoxic area in the

western hemisphere (CAST, 1999). Since 1993, mid-summer 

bottom water hypoxia in the northern Gulf of Mexico has been

larger than 3,860 square miles (except in 2000). In 1999, it

reached over 7, 700 square miles (CENR, 2000). 

Indicator Gaps and Limitations

Coverage of the nation’s coastline is limited. Probabilistic surveys

like those in the Northeast, the Southeast, and the Gulf Coast do

not exist for areas north of Cape Cod or for the Great Lakes.

Similar probabilistic data do not exist for Puget Sound or San

Francisco Bay.

The relationship between threshold values and effects on aquatic

life is neither well established nor expected to be consistent 

across all regions. For example, warm water environments would be

naturally lower in DO. The criteria of two ppm might not be 

sufficiently protective in cold water environments. Much of the data

apparently represent point-in-time measures. If so, the data contain

limitations, and the length of time that dissolved oxygen concentrations were below two ppm would not have been considered.

The data set incorporates a mix of time series and point-in-time

measures based on historical data sets collected. Where time

series data are available and used, better estimates of oxygen 

conditions would be achieved. Point-in-time measures are weaker.

Since only one season, the summer, was generally represented,

oxygen stress in other seasons would be missed. 

Data Source

Dissolved oxygen data used for this indicator are from the EPA’s

Environmental Monitoring and Assessment Program Estuaries

database. (See Appendix B, page B-10, for more information.) 

Indicator Dissolved oxygen in coastal waters – Category 2

2-20 2.2 Waters and Watersheds Chapter 2 - Purer Water

Coverage: United States east coast (excluding waters north of Cape Cod), 

 west coast, and Gulf of Mexico

Source: EPA, Office of Research and Development and Office of Water. 

National Coastal Condition Report. September 2001.

Exhibit 2-10: Estuarine area with poor (<2 ppm), 

fair (between 2 and 5 ppm), and good (>5 ppm) 

dissolved oxygen conditions, 2000

>5 ppm

Good

2-5 ppm

 Fair 80%

16%

4%

<2 ppm Poor
Technical Document Q EPA’s Draft Report on the Environment 2003

Total organic carbon (TOC) is a measure of the concentration of

organic matter in sediments. It represents the long-term, average

burial rate of organic matter in the sediments. High TOC values

can arise from frequent algal blooms in the overlying waters or

transport of sewage or high organic waste from point sources.

TOC can also sequester or chelate organic compounds and some

metals and make them less biologically available for uptake.

TOC values are calculated as percent carbon in dried sediments.

Assessment categories for the Mid-Atlantic estuaries were: 

Q Low: 1 percent

Q Intermediate: >1 to 3 percent

Q High: >3 percent

What the Data Show

Carbon values ranged from 0.02 to 13 percent throughout the

mid-Atlantic estuaries (Paul, et al., 1999). For the mid-Atlantic

region, about 60 percent of the estuarine sediments had low

TOC values, about 24 percent had intermediate TOC values,

and 16 percent had high TOC sediment values (EPA, ORD, 

May 2003); (Exhibit 2-11). Values ranged from Delaware Bay

with about 95 percent of its sediments having low TOC values

to the Chowan River in the Albemarle-Pamlico Estuary with 

65 percent of its sediments having high TOC values (EPA, ORD,

May 2003). The Chesapeake Bay mainstem had about 

65 percent of its sediments with low TOC values and about 

15 percent with high TOC values.

Indicator Gaps and Limitations

These data are from a survey of mid-Atlantic estuaries and cannot

be extrapolated to national-scale estimates. Samples were collected

during an EMAP-defined index period of summer months.

Data Source

The total organic carbon data for this indicator come from EPA’s

Environmental Monitoring and Assessment Program, Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Program. (See Appendix B,

page B-10, for more information.)

Indicator Total organic carbon in sediments – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-21

Exhibit 2-11: Percentages of Mid-Atlantic estuarine area 

with low, intermediate, and high total organic carbon 

content in sediments, 1997-1998

Low

60%

Intermediate 

24%

High

16%

Note: High is > 3%; Intermediate is >1 to 3%; Low is <1%

Source: EPA, Office of Research and Development. Mid-Atlantic Integrated 

Assessment, MAIA - Estuaries 1997-98, Summary Report. May 2003.

Indicator Chlorophyll concentrations – Category 2

Chlorophyll concentrations are a measure of the abundance of

phytoplankton. Phytoplankton account for most of the plant

production in the ocean. Excessive growth of phytoplankton, as

measured through chlorophyll concentrations, can lead to

degraded water quality, such as noxious odors, decreased water

clarity, oxygen depletion, and harmful algal blooms. Excess

phytoplankton growth is usually associated with increased nutrient

inputs (e.g., watershed or atmospheric transport, upwelling) or a

decline in filtering organisms such as clams, mussels, or oysters

(The Heinz Center, 2002).
EPA’s Draft Report on the Environment 2003 Q Technical Document

Chlorophyll concentrations were considered for both estuarine

and ocean waters within 25 miles of the coast (The Heinz Center,

2002). Three categories of concentrations were established by

EPA for mid-Atlantic estuaries: 

Q Good: 15 ppb

Q Fair: 15-30 ppb

Q Poor: > 30 ppb

The lower threshold of 15 ppb chlorophyll is equal to the restoration

goal recommended for the survival of submerged aquatic vegetation

(SAV) in Chesapeake Bay (Batiuk, et al., 2000).

For ocean waters, the indicator reports the average value for the season, displaying the highest concentrations for each region. Estuarine

chlorophyll concentrations are not available for national reporting.

Ocean data, based on surface reflectance, were inferred from National

Aeronautics and Space Administration’s (NASA’s) Sea-viewing Wide

Field-of-View-Sensor. Data were analyzed for nine ocean regions by

NOAA’s National Ocean Service. The estuarine chlorophyll concentrations were obtained from field measurements as part of the EPA EMAP

Mid-Atlantic Estuaries Program.

What the Data Show

Analysis of the data showed that:

Q Ocean chlorophyll concentrations ranged from average seasonal concentrations of 0.1 to 6.5 ppb (Exhibit 2-12) (The Heinz

Center, 2002). 

Q The highest ocean chlorophyll concentrations (4.8 to 6.5 ppb)

occurred in the Gulf of Mexico, with the lowest concentrations (

0.1 ppb) in Hawaiian waters (Exhibit 2-12). 

Q Southern California had the next lowest chlorophyll concentrations—between 1.1 and 1.5 ppb (Exhibit 2-12). 

Q Other ocean waters (e.g, north, mid-, and south Atlantic, and the

Pacific Northwest) had chlorophyll concentrations ranging from 

2 to 4.5 ppb (Exhibit 2-12).

Q Chlorophyll concentrations in the mid-Atlantic estuaries ranged

from 0.7 to 95 ppb in 1997 and 1998 (EPA, ORD, May 2003). 

Q About 33 percent of the mid-Atlantic estuarine area had chlorophyll concentrations exceeding 15 ppb. 

Q The Delaware Estuary showed a wide range of chlorophyll concentrations, from a low (< 15 ppb) in the Delaware Bay, to intermediate

(15-30 ppb) in the Delaware River, to very high (> 80 ppb) in the

Salem river. 

Q The western tributaries to the Chesapeake Bay were consistently

high in chlorophyll a, with more than 25 percent of the area

showing > 30 ppb chlorophyll concentrations. 

Q Chlorophyll concentrations in the coastal bays were generally

low (< 15 ppb), even though nutrients were elevated because

of increased turbidity and low light penetration.

Indicator Gaps and Limitations

Algorithms used to translate spectral reflectance data into chlorophyll

concentrations currently provide only rough estimates of concentrations in those waters where concentrations of suspended sediments

and colored dissolved organic matter are high (e.g., near-shore waters

influenced by surface and ground water discharges, coastal erosion,

and sediment resuspension). 

The data presented here are based on a fairly coarse scale (six-mile

resolution). Currently, data showing relative changes in chlorophyll

within a region can be reliable; however, data showing actual concentrations for any given region might vary by a factor of two. Thus,

unless differences are large, meaningful comparisons between regions

are not yet possible.

The mid-Atlantic estuary data are one-time estimates of chlorophyll

content in mid-Atlantic estuaries only, so these data cannot be projected to the national scale or to different time periods. Samples were

Indicator Chlorophyll concentrations – Category 2 (continued)

2-22 2.2 Waters and Watersheds Chapter 2 - Purer Water

Exhibit 2-12: Chlorophyll concentrations in 

U.S. coastal waters, 1998-2000

7

6

5

4

3

2

1

0

1995 2000

Chlorophyll Concentration (parts per billion)

North Atlantic

Mid-Atlantic

South Atlantic

Gulf of Mexico

Pacific 

Northwest

Alaska

Bering Sea

Hawaii

Southern

California

Source: Modified from The Heinz Center. The State of the Nation's 

Ecosystems. 2002. Data from National Oceanic and Atmospheric 

Administration, National Ocean Service.

Coverage: all U.S. waters, 

including Alaska and Hawaii, 

within 25 miles of the coast. 

96 97 98 99
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-23

Additional Consideration: Eutrophication

Another key issue relevant to understanding the condition of

coastal waters is eutrophication. Eutrophication is a natural process,

through which there is “an increase in the rate of supply of organic

matter” to a waterbody (Nixon, 1995). This process usually represents an increase in the rate of algal production. Under natural conditions, algal production is influenced by a gradual buildup of plant

nutrients in ecosystems over long periods of time and generally

leads to productive and healthy estuarine and marine environments.

However, in recent years, human activities have substantially

increased the rate of delivery of plant nutrients to many estuarine

and marine areas (NRC, 2000; Peierls, et al., 1991; Turner and

Rabalais, 1991). As a result, algal production in many estuaries has

increased much faster than would occur under natural circumstances. This accelerated algal production is referred to as “cultural”

or “anthropogenic” eutrophication and often results in a host of

undesirable conditions in estuarine and marine environments.

These conditions, which include low dissolved oxygen concentrations,

declining sea grasses, and harmful algal blooms, might impact the

uses of estuarine and coastal resources by reducing the success of

commercial and sport fisheries, fouling swimming beaches, and 

causing odor problems from the decay of excess amounts of algae

(NRC, 2000; Duda, 1982). Despite much research, however, the link

between coastal eutrophication and effects on living marine resources

and fisheries is not well understood or quantified (NRC, 2000;

Boesch, et al., 2001). 

Between 1992 and 1998, NOAA conducted a survey and series of

regional workshops to synthesize the best available information on

eutrophication-related symptoms in 138 estuaries. Data from these

surveys are presented in NOAA ‘s National Estuarine Eutrophication

Assessment (Bricker, et al., 1999). They indicate that the nation’s

estuaries exhibit strong symptoms of eutrophication, which were

reported by EPA to be “poor” (EPA, ORD, OW, September 2001).

When data on the symptoms of eutrophication are combined, they

suggest that 40 percent of the surface area of the nation’s estuarine

waters exhibit high levels of eutrophic condition (Exhibit 2-13).

Many of these waters are in the mid-Atlantic and gulf regions of the

U.S. Moreover, based on expert opinion, eutrophic conditions are

expected to worsen in 70 percent of U.S. estuaries by 2020 

(Bricker, et al., 1999).

These eutrophication estimates are largely based upon best

professional judgement. They do not adequately reflect regional

differences that may occur naturally, so high scores may not be a true

measure of eutrophication. Also, there are no strong scientific data to

indicate that the thresholds used are indeed indicative of eutrophic

conditions on a region-by-region basis. Use of SAV loss, macroalgae,

and epiphytic growth is not appropriate for regions/areas where SAV

beds or macroalgae are not present (e.g., South Carolina, Georgia).

Standard methods do not appear to have been used among states.

For all these reasons, these data were judged not to be sufficiently

robust to qualify as an indicator for purposes of this report.

Nevertheless, accelerated eutrophication can be an important

symptom of environmental decline in estuarine and marine areas.

35%

Low

40%

High

25%

Moderate

Exhibit 2-13: Percent of estuaries with high, moderate, 

and low levels of eutrophic condition, 1998

Coverage: United States, excluding the Great Lakes

Source: Bricker et al. National Estuarine Eutrophication Assessment: Effects of 

Nutrient Enrichment in the Nation's Estuaries. 1999; EPA, Office of Research and 

Development and Office of Water. National Coastal Condition Report. 

September 2001.

collected during an EMAP-defined index period of summer months

and do not represent conditions at different times.

Data Source

Ocean data are found in the National Aeronautics and Space

Administration’s Sea-Viewing Wide Field-of-View Sensor. Estuarine

chlorophyll concentrations are found in the EPA’s Environmental

Monitoring and Assessment Program, Mid-Atlantic Integrated

Assessment (MAIA) Estuaries Program. (See Appendix B, page B-11,

for more information.)

Indicator Chlorophyll concentrations – Category 2 (continued)
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-24 2.2 Waters and Watersheds Chapter 2 - Purer Water

Therefore, eutrophication should be reconsidered as an indicator in

the future if and when scientifically sound data become available.

2.2.4 What are pressures to 

water quality?

A complex suite of pressures weighs on surface water resources. EPA

data on water quality provide some measure of the major stressors.

Under the Clean Water Act, EPA requires states to define and list

waters under their jurisdiction that are impaired, and to identify the

causes of those impairments and develop a program to manage and

control the causes. In 1998, more than 21,000 waterways were

identified as impaired under the provisions of Section 303(d) of the

CWA (EPA, OW, March 2003). The following top five causes of

impairment accounted for 60 percent of the cases: 

Q Sediment/siltation

Q Pathogens

Q Metals

Q Nutrients 

Q Organic enrichment/low dissolved oxygen

The next five causes account for additional 21 percent of 

impairment: 

Q Habitat alteration

Q Thermal modifications

Q Low or high pH

Q Pesticides

Q Fish consumption advisories

Twenty indicators have been identified to help answer the question

“What are the pressures to water quality?” These indicators have

been divided into three categories:

General pressures—Section 2.2.4.a presents six indicators of general

pressures that relate in some way to habitat quality but do not fall

into a specific stressor category.

Nutrient pressures—Section 2.2.4.b presents six indicators that

relate specifically to nutrient enrichment.

Chemical contaminant pressures—Section 2.2.4.c discusses eight

indicators that describe chemical contamination.

These indicators do not address sediment/siltation or pathogens

(the two most important causes of water quality impairment as identified under Section 303[d] of the Clean Water Act), nor do they

address another key concern—the impact of invasive species.

Additional pressures to water quality are discussed in the Ecological

Condition, Better Protected Land, and Cleaner Air chapters. 

2.2.4.a General Pressures

General pressures that alter aquatic ecosystems and for which

indicators are available include (1) the extent of urban land cover

and agricultural lands in stream riparian areas, and (2) the extent of

coastal development, as represented by population density.

Additional indicators of pressures on streams relate to changes in

stream flow and altered in-stream habitat. These six indicators,

discussed in this section, address pressures directly on stream

ecosystems and coastal areas, but they do not attempt to define

pressures on lakes, ponds, reservoirs, or wetland resources, even

though the pressures are likely comparable. 

The difference in pressures related to urban development versus

pressures from agricultural activities generally are a function of the

location of, extent of, and change in urban and agricultural areas.

Coastal development data, in the form of population density,

suggest strong pressures on coastal systems today and in the future.

Data on stream flow indicate that changes in minimum and maximum

flow have increased slightly over the last three decades and that

maximum flows in some areas have increased significantly. Zero (no)

flow data for grassland and shrubland streams are consistent with

these observations in that the percent of streams with no- flow

periods has decreased. 

Indicators

Percent urban land cover in riparian areas

Agricultural lands in riparian areas

Population density in coastal areas

Changing stream flows

Number/duration of dry stream flow periods in 

grassland/shrublands

Sedimentation index

Atmospheric deposition of nitrogen

Nitrate in farmland, forested, and urban streams and ground water

Total nitrogen in coastal waters

Phosphorus in farmland, forested and urban streams

Phosphorus in large rivers

Total phosphorus in coastal waters

Atmospheric deposition of mercury

Chemical contamination in streams and ground water

Pesticides in farmland streams and ground water

Acid sensitivity in lakes and streams

Toxic releases to water of mercury, dioxin, lead, PCBs, and PBTs

Sediment contamination of inland waters

Sediment contamination of coastal waters

Sediment toxicity in estuaries
Technical Document Q EPA’s Draft Report on the Environment 2003

This indicator provides a snapshot in time of the potential stress

to stream ecosystems across the nation due to urban development. Specifically, the indicator examines the extent of land

cover within riparian zones, which are defined as the 30-meter

buffer on each side of a stream or river. The indicator focuses

on land cover along streams or rivers within watersheds categorized by the U.S. Geological Survey (USGS) as eight-digit HUCs

under its hydrologic unit code (HUC) categorization system.

To calculate the extent of urban land cover, each of these buffer

zones was divided into grid cells (of 15 minute latitude by 15

minute longitude dimensions). The extent of urban land cover was

calculated as the percent of grid cells with land cover, divided by

the total number of grid cells. To make this calculation:

Q Stream map sets were derived from remote sensing techniques,

generally aerial photography and satellite imagery. 

Q The land cover data sets were collected using remote sensing

techniques, generally satellite imagery, with ground truth fieldwork.

Q Stream extent and locations were defined as any line or polygon feature attributed as “stream/river.” This is consistent with

the definition in the USGS’s National Hydrography Dataset

(NHD), a key data source for this indicator.

Q Urban land cover was defined as (1) the sum of low-intensity

residential, high-intensity residential, and commercial/industrial/transportation land cover types in the National Land Cover

Database (NLCD) and (2) the sum of both high-intensity and

low-intensity developed land cover types in the Coastal Change

Analysis Program (C-CAP).

What the Data Show

The analysis indicates that nearly 80 percent of the watersheds

(8-digit HUCs) in the continental U.S. have less than 2 percent

urban land uses within 30 meters of streams. Five percent of

watersheds (8-digit HUCs) have urban land uses of greater than 

8 percent within 30 meters of streams. Less than 1 percent of the

nation’s watersheds (8-digit HUCs) have more than 25 percent

urban uses within stream riparian areas. Watersheds with streamside urban development tend to be concentrated in certain parts

of the country (e.g., the Midwest, Southeast, and Northeast). 

Indicator Gaps and Limitations

The streams data set is known to contain both systematic and

random errors. Many of these errors, such as positional accuracy

of stream segments due to digitizing accuracy, are minimized due

to the scale of this analysis (i.e., at the 8-digit HUC level). But

stream omission, the degree of which varies between different

scale maps (i.e., 30- by 60-minute quadrangle maps), has a higher

impact on potential error. In addition, the accuracy of whether or

not a stream was perennial also varied between quadrangle maps,

preventing a more accurate representation of riparian areas.

This indicator only examines urban land within 30 meters of

streams and rivers, which means that more significant urban development at distances beyond 30 meters is not evaluated. The

analysis is not a standardized ongoing assessment. Because the

land cover data sets exists only for a single year, changes in the

amount of urban land cover over time are not addressed by this

indicator at present.

Data Source

Information is available from the specific program datasets

(National Land Cover Database, Coastal Change Analysis Program,

National Hydrography Dataset, and Hydrologic Unit Code). Data

were summarized by the EPA. (See Appendix B, page B-11, for

more information.)

Indicator Percent urban land cover in riparian areas – Category 2 

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-25
EPA’s Draft Report on the Environment 2003 Q Technical Document

Agricultural land uses in riparian areas may have environmental

effects, due to erosion and disturbance of riparian habitat. When

land immediately adjacent to streams is used for agricultural purpose, this may affect water quality in a number of ways:

Q Runoff from plowed fields can potentially become a source of

stream sediment.

Q Fertilizers and pesticides are often conveyed to streams by

runoff or by drainage.

Q Grazing animals may contaminate streams with coliform

bacteria.

Results for this indicator are expressed in bank miles, calculated as

the percent of agricultural land cover within the stream corridor,

multiplied by the total length of stream bank within the 8- digit

HUC. The data sets and analytical procedures are the same as

those for the urban land in riparian areas indicator described

above.

What the Data Show

The major areas of high agricultural activities in riparian areas of

the U.S. are found in the Midwest, in the Southeast, east of the

Cascade Mountains in Washington state, and in the inland valleys

of California. The arid Southwest has very few stream miles in

agriculture, due both to a low stream density and limited agriculture. Conversely, areas with the highest number of stream miles in

agriculture are in watersheds that have extensive agriculture and

high stream density. Only one percent of the watersheds (8-digit

HUCs) in the conterminous U.S. have no stream miles in agriculture. Ten percent of the watersheds (8-digit HUCs) in the conterminous U.S. have more than 1,500 miles of streams in agriculture.

About half of the watersheds (8-digit HUCs) in the conterminous

U.S. have less than 250 miles of streams in agriculture.

Indicator Gaps and Limitations

The issues associated with this indicator are the same as those

described for the previous indicator “percent urban land cover in

riparian areas.” Because the classified land cover data sets were

only produced once, changes in the amount of agricultural land

cover over time are not addressed by this indicator at present.

Refer to the “Indicator Gaps and Limitations” section in the 

discussion of the previous indicator for details.

Data Source

EPA’s Office of Research and Development analyzed and summarized data from the National Land Cover Database for stream

miles with agricultural uses. Information is available from the specific program datasets (NLCD, C-CAP, NHD, and HUC). (See

Appendix B, page B-11 for more information.)

Indicator Agricultural lands in riparian areas – Category 2

2-26 2.2 Waters and Watersheds Chapter 2 - Purer Water

Land along the U.S. coastline is experiencing more acute pressure

from population growth than other areas. Using primarily census

data, NOAA has produced several reports on population distribution, density, and growth in coastal areas. These reports describe

the pressure on coastal environments from land development. 

What the Data Show

The NOAA reports find that coastal areas are the most developed in the nation. The narrow fringe of coastline, comprising

17 percent of our nation’s total land area, contains 53 percent

of the nation’s population. The rate of population growth along

the coast is faster than for the nation as a whole. At an average

growth rate of 3,600 people per day, coastal population is

expected to reach 165 million by 2015 (NOAA, 1998). 

Indicator Gaps and Limitations

The NOAA estimates of coastal population and pressures are likely

to be an overestimate, as data are aggregated by counties, which

have extensive inland areas in addition to coastal shoreline. 

Data Source

Data for this indicator are from a report on urban development in

coastal areas by the U.S. Department of Commerce, National

Oceanic and Atmospheric Administration. (See Appendix B, 

page B-11, for more information.)

Indicator Population density in coastal areas – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

Flow is a critical aspect of hydrology in streams. Low flows define

the smallest area available to stream biota during the year; high

flows shape the stream channel and clear silt and debris from the

stream. Also, some fish depend on high flows for spawning (The

Heinz Center, 2002). The timing of a stream’s high and low flows

can influence many ecological processes. Changes in flow can be

caused by dams, water withdrawal, changes in land use, and climate trends. This indicator reports the percentage of streams or

rivers with major changes in the magnitude or timing of their high

or low flows over three decades (1970s, 1980s, 1990s) compared

to a reference period from 1930 to 1949. 

The USGS stream gauge database, which served as the data

source for this indicator, contains 867 gauging sites with at least

20 years of discharge records within the target dates 1930 to

1949, and 10 years of records for the 1970s, 1980s, and 1990s.

The measures were 7-day low flow and the corresponding Julian

days and the average 1-day high flow and Julian day. 

What the Data Show

The percentage of streams and rivers with major changes in their

high or low flows or the timing of those flows (i.e., compared to

the same data for those streams or rivers as recorded between

1930 and 1949) increased slightly from the 1970s to the 1990s

(The Heinz Center, 2002). The number whose high flows were

well above the flows in those same streams and rivers between

1930 and 1949 increased by approximately 30 percent in the

1990s (Exhibit 2-14). The baseline period of 1930 to 1949

included some droughts, which may partially explain the increase

in high flows in subsequent decades. However, much of this baseline period also preceded widespread irrigation projects, which

means that fewer high flows would be expected in subsequent

decades.

Indicator Gaps and Limitations

Data from the period 1930 to 1949 are being used here as a

practical baseline for historical comparison, even though many

dams and other waterworks had already been constructed by this

time, and even though this period was characterized by low rainfall

in some parts of the country. For this reason, it may be more useful to compare changes in stream flows on a decade-by-decade

basis rather than to the 1930 to 1949 baseline period selected

here.

Although the sites analyzed here are spread widely throughout

the U.S., gauge placement by the USGS is not a random process.

Gauges are generally placed on larger, perennial streams and

rivers, and changes seen in these larger systems may differ from

those seen in smaller streams and rivers. In addition, the USGS

gauge network does not represent the full set of operating stream

flow gauges in the U.S. The U.S. Army Corps of Engineers, for

example, operates gauges, and those data are not available

through the USGS; they were not used in this analysis.

Data Source 

Data for this indicator came from the U.S. Geological Survey

gauging station network, compiled for The Heinz Center (2002).

(See Appendix B, page B-12, for more information.)

Indicator Changing stream flows – Category 1

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-27

Exhibit 2-14: Percent of streams with changes in high 

flows (1970s-1990s) compared to baseline high flow 

data (1930-1949)

100

80

60

40

20

0

1970s 1980s 1990s

Percent of Streams/Rivers with Major Changes

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data 

from the U.S. Geological Survey.

Coverage: lower 48 states

Note: Totals may add to more than 100%, because both the timing and 

magnitude may change in a single stream or river.

Increase

Decrease

Timing
EPA’s Draft Report on the Environment 2003 Q Technical Document

Many grassland/shrublands are located in arid climates where

water availability is critical. The number and duration of dry periods in streams and rivers is used as a hydrology/geomorphology

indicator in the Heinz report (The Heinz Center, 2002). Changes

in the number and/or duration of no-flow periods can significantly

stress aquatic plants and animals. These alterations can result

from changes in agricultural management or irrigation practices,

development, change in flow regulation below dams, or depletion

of shallow ground water. Riparian condition is critical for grassland

and shrubland streams. Because most of the streams are

ephemeral, aquatic organisms have evolved to complete their life

histories during periods when water is available (Fisher, 1995).

Increasing the percentage of no-flow periods can significantly

stress riparian and aquatic communities.

Gauging sites with at least 50 percent grassland/shrubland were

identified for 4-digit HUC watersheds. The NLCD coverage was

used to identify these areas as grassland/shrubland. The number

of sites with at least one no-flow day in a year was determined for

each year from 1950 to 1999. The corresponding percentage of

area as grassland/shrubland for that year was also calculated. To

analyze the duration of no-flow, only sites with at least one noflow day in each decade between October 1, 1949, and

September 30, 1999, were considered. This analysis considered

whether there was an increase, decrease, or minimal change in the

number of no-flow days, compared to the long-term (50-year)

average for each stream.

What the Data Show

The percentage of no-flow periods has decreased in all grassland/shrubland regions of the West (The Heinz Center, 2002).

The percentage of no-flow periods was similar in the 1950s and

1960s and then generally decreased in the 1970s, 1980s, and

1990s (Exhibit 2-15) (The Heinz Center, 2002). The 1980s was

a relatively wet period, during which some of the smallest percentages of no-flow periods existed in a 50-year period of record

(The Heinz Center, 2002). The duration of no-flow periods also

decreased during the 1970s through the 1990s, compared to the

1950s and 1960s (The Heinz Center, 2002).

Indicator Gaps and Limitations

These data are from USGS gauging stations, which may be found

on larger, perennial streams; thus, these data may not reflect conditions on very small streams. Data limitations, generally, are similar to those described for the “number/duration of dry stream

flow periods in grasslands/shrublands” indicator described on the

previous page.

Data Source

The data source for this indicator was the U.S. Geological Survey

gauging stations, analyzed by Colorado State University for The

Heinz Center. (See Appendix B, page B-12, for more information.)

Indicator Number/duration of dry stream flow periods in grassland/shrublands – Category 2

2-28 2.2 Waters and Watersheds Chapter 2 - Purer Water

Exhibit 2-15: Percent of streams that have zero-flow 

periods, 1950s-1990s

100

80

60

40

20

0

1950s 1960s 1970s 1980s 1990s

Percent of All Streams in Analysis

Coverage: grassland/shrubland regions in lower 48 states.

All Areas

California/ 

Mediterranean

Desert/Shrub

Grassland/ 

Steppe

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data 

from the U.S. Geological Survey.
Technical Document Q EPA’s Draft Report on the Environment 2003

Stream channels undergo a long-term adjustment to a regionspecific rate of sediment supply that is delivered by erosion

processes from natural disturbance. The size distribution of

streambed particles is dependent upon the relationship between

sediment supply and stream sediment transport capability. Under

a natural disturbance regime, sediment supply in watersheds that

are not altered by human disturbances may be roughly in longterm equilibrium with stream sediment transport. In watersheds

that are relatively undisturbed by humans, the relationship

between bed particle size and stream transport capability should

tend toward a characteristic value that is typical to the region.

Human activities may increase sediment input rates to streams,

resulting in higher amounts of fine substrates in sediments than

the predicted regional value.

Higher sedimentation rates can significantly alter instream habitat.

These alterations are the greatest stressor to mid-Atlantic streams

and many other streams throughout the U.S. For example, change

in channel morphology can affect stream biota and ecological

condition. Thrush, et al. (2000) provide 10 geomorphic attributes

that are needed for suitable stream habitat, in addition to critical

channel morphological indicators.

A sedimentation index was developed for Mid-Atlantic Highland

streams to assess the quality of instream habitat to support

aquatic communities (Kaufmann, et al., 1999). Stream

sedimentation was defined as an increase or excess in the amount

of fine substrate particles (smaller than 16-mm diameter) relative

to an expected reference value that is based on the region and

the sediment transport capability of each sample stream reach.

Streams were given the following ratings with respect to

sedimentation:

Q “Good” when the proportion of fine particles was at least 10

percent below the predicted value.

Q “Fair” when the population of fine particles ranged from 10 percent below to 20 percent above the predicted value.

Q “Poor” when the proportion of fine particles was more than 20

percent above regional mean expectations.

What the Data Show

Based on the sedimentation index, about 35 percent of the

Mid-Atlantic Highland stream miles had good instream habitat,

40 percent had fair instream habitat, and 25 percent of the

stream miles had poor instream habitat (Exhibit 2-16) (EPA,

ORD, Region 3, August 2000).

Indicator Gaps and Limitations

This sedimentation index has been applied only in the context

of the mid-Atlantic region and cannot be used for a national

assessment. The index itself may not apply equally to other

regions of the nation.

Data Source

The data source for this indicator was EPA’s Mid-Atlantic

Highlands Streams Assessment, part of the Environmental

Monitoring and Assessment Program. (See Appendix B, 

page B-12, for more information.)

Indicator Sedimentation index – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-29

Source: EPA Region 3 and the Office of Research and Development. Mid-Atlantic 

Highlands Streams Assessment. August 2000.

Exhibit 2-16: Percent of Mid-Atlantic highland streams 

exhibiting good, fair, and poor habitat condition based 

upon a sedimentation index, 1993-1994

Fair

40%

Good

35%

Poor

25%
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-30 2.2 Waters and Watersheds Chapter 2 - Purer Water

2.2.4.b Nutrient Pressures

Nutrient enrichment by nitrogen and phosphorus is one of the

leading causes of water quality impairment in the nation’s rivers,

lakes, and estuaries. In a l998 water quality report to Congress,

nutrients were listed as a leading cause of water pollution. About

half of the nation’s waters surveyed by states do not adequately

support aquatic life because of excess nutrients. In 1998, states

reported that excessive nutrients have degraded almost 2.5 million

acres of lakes and reservoirs and over 84,000 miles of rivers and

streams to the extent that they no longer meet basic uses such as

supporting healthy aquatic life. Nutrients have also been associated

with both the large hypoxic zone in the Gulf of Mexico, the hypoxia

observed in several East Coast states, and Pfisteria-induced fish kills

and human health problems in the coastal waters of several East

Coast and Gulf states. 

Many of the nutrients used in chemical fertilizers are water soluble.

Consequently, one of the major potential environmental effects of fertilizer usage is the nitrogen or phosphorus that may find its way into

water systems, affecting water quality and aquatic habitats. Another

major source of nutrients from agricultural lands are those related to

animal feed operations. Nutrients, particularly nitrogen and phosphorus, increase the levels of algae in receiving waterbodies.

Most of the streams that are enriched with nutrients lie in drainage

areas for agricultural and/or urban land. Forested landscapes rarely

contribute to heightened water concentrations of these nutrients.

Ground water from more than half the sites sampled in a nationwide

study contained nutrients at concentrations higher than natural

background levels. Data presented in Chapter 3, Better Protected

Land, describe a USGS risk analysis that evaluated the likelihood of

ground water contamination from nitrate resulting from a combination of well-drained soils and a high proportion of cropland to woodland. The data illustrate a clear relationship between potential

ground water contamination and predominantly agricultural areas of

the country (see Chapter 3–Better Protected Land).

“Nitrogen export” is the annual quantity of total nitrogen produced

by nitrogen sources in a watershed that leaves the watershed

through a river or stream that connects to other watersheds downstream. Estimates of total nitrogen (TN) export were developed by

Smith, et al. (1997) through analysis of data from monitoring stations in the USGS’s National Stream Quality Accounting Network

(NASQAN) SPARROW (SPAtially-Referenced Regressions On

Watershed attributes). This model relates in-stream measurements of

TN export to point and non-point sources of pollution, and to landsurface and stream-channel characteristics in the watersheds that

contain the monitoring stations. This modeling was performed using

data from approximately 400 long-term stream monitoring sites.

Using these data, the model empirically estimated the delivery of

nutrients to streams and the outlets of watersheds from point and

non-point sources.

This section presents six indicators of pressures on water quality

related to nutrient enrichment: 

Q Atmospheric deposition of nitrogen

Q Nitrates in farmland, forested, and urban streams and ground water

Q Total nitrogen in coastal waters

Q Phosphorus in farmland, forested, and urban streams

Q Phosphorus in large rivers

Q Phosphorus in coastal waters

Chapter 3–Better Protected Land, discusses the potential for nutrient runoff from farmlands.

Nitrogen, essential to life, is a component of proteins and 

nucleic acids. Natural and human processes convert nitrogen gas

to a variety of usable forms, including nitrogen oxides, ammonia,

and organic nitrogen. Natural sources of nitrogen oxides and

ammonia include volcanic eruptions, lightning, forest fires, and

certain microbial processes. Anthropogenic sources contribute

about the same amount of nitrogen oxides and ammonia to the

environment as do natural sources. The largest single source of

nitrogen oxides to the atmosphere is the combustion of fossil

fuels (such as coal, oil, and gas) by automobiles and electric

power plants (Schlesinger, 1997). The largest sources of ammonia emissions are fertilizers and domesticated animals (such as

hogs, chickens, and cows).

In some places, nitrogen deposited from the atmosphere is a large

percentage of the total nitrogen load. For instance, AlbemarlePamlico Sound in North Carolina receives 38 percent of its nitrogen from the atmosphere (EPA, OAQPS, June 2000). As human

sources of nitrogen compounds to the atmosphere increase, the

importance of atmospheric deposition of nitrogen to bodies of

water will increase as well. 

Indicator Atmospheric deposition of nitrogen – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

The deposition of nitrogen compounds

on land or water can take several forms.

Wet deposition occurs when air pollutants fall with rain, snow, or fog. Dry

deposition is the deposition of pollutants as dry particles or gases. In either

form, the pollutants can reach bodies

of water as direct deposition falling

directly into the water or as indirect

deposition—falling onto land and

passing into a body of water as runoff.

In either case, atmospheric deposition

is often one of the major sources of

nitrogen in surface waters. 

This indicator focuses on atmospheric

deposition of inorganic nitrogen, as it

is the most immediately available form

of nitrogen in the environment. Its

components, nitrate and ammonium,

are presented using the National

Atmospheric Deposition

Program/National Trends Network

(NADP/NTN) data collected in 2001.

What the Data Show

Ammonium deposition is lowest in the

western states, where it is generally less

than 1 kg/ha. Highest rates occur in

the upper midwestern states in the

upper Mississippi River watershed

(Exhibit 2-17). Nitrate deposition also

is low in the western states (< 4 kg/ha).

Highest deposition rates occur in the

upper Midwest and in the eastern

states (Exhibit 2-18). High ammonium

values are associated with wastes from

animal agriculture, while nitrates are

largely from fertilizers used in row crop

agriculture.

Indicator Gaps and

Limitations

This indicator measures wet deposition,

not dry deposition. Total nitrogen deposition is not measured.

Indicator Atmospheric deposition of nitrogen – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-31

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4.0

0.4

2.3 2.3

3.0

2.0

1.2

2.5

1.1

0.2

1.3

0.4

2.7

0.7

3.3

3.3

3.7

1.7

0.7

0.7

0.6

2.8

2.7

0.7

0.8

2.6

0.7

1.0

0.8

1.7

4.2

2.1

2.1

1.3

0.7

0.9

1.4

3.0

2.5

3.1

3.3

2.3

1.6

0.6

1.5

2.3

1.4

3.2 2.0

3.3 1.8

0.6

0.5

1.1

0.4

0.2

1.5

1.6

0.6

0.7

1.2

1.0

2.1

1.8

0.5

1.3

1.2

1.6

1.3

1.6

1.7

1.3

1.5

1.6

1.5

5.0

5.0

0.5 0.5

2.8

3.3

2.3

3.9

4.6 4.1

2.7

3.7

3.3

3.9

4.4

3.0 1.7

2.0

1.2

2.7

2.7

0.9

1.1

0.9

1.1 3.2

3.4 4.3

4.3

2.8 3.1 2.2

2.6

3.9

4.5

3.7

3.5

3.4

2.2

2.1

0.6

0.7

0.6

0.6

1.9

1.7

3.2

3.9

1.5 2.9

2.2

2.8

3.2 3.5

1.3

2.8

0.7

0.3

2.9

2.9

3.6 1.8

1.7 2.1

1.9

2.1

4.1

3.3 2.9

3.4

2.1

2.7

3.4

0.1

0.3 0.2

0.71.5

2.8

2.4 3.0

2.8

2.0

2.1 4.4

2.3

1.9

2.5

2.0

2.0

0.7 2.0

1.4

2.5

2.4

0.5

0.7

2.0

2.0

2.7

1.5

2.6

0.5

0.4 0.7

3.7

3.9

5.1

3.0

4.6

5.3 4.8

2.7

0.5

Exhibit 2-17: Ammonium wet deposition, 2001

Sites not pictured:

AK01

AK03

HI99

VI01

0.1 kg/ha

0.1 kg/ha

0.5 kg/ha

0.3 kg/ha

Coverage: lower 48 states

Source: National Atmospheric Deposition Program, National Trends Network. 2001. 

(March 25, 2003; http:..nadp.sws.uiuc.edu/isopleths/maps2001/nh4dep.pdf).

Ammonium as (NH4) kilograms per hectare (kg/ha)

Exhibit 2-18: Nitrate wet deposition, 2001

Sites not pictured:

AK01

AK03

HI99

VI01

1 kg/ha

<1 kg/ha

2 kg/ha

3 kg/ha

Coverage: lower 48 states

Source: National Atmospheric Deposition Program, National Trends Network. 2001. 

(March 25, 2003; http://nadp.sws.uiuc.edu/isopleths/maps2001/no3dep.pdf).

Nitrate as NO3 kilograms per hectare (kg/ha)

< 4

4 - 6

6 - 8

8 - 10

10 - 12

12 - 14

14 - 16

16 - 18

18 - 20

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2
EPA’s Draft Report on the Environment 2003 Q Technical Document

Additionally, the indicator estimates deposition only to the surface areas, not directly to the water, except where large waterbodies

are present.

Data Source

The data source for this indicator was the interagency National

Atmospheric Deposition Program. (See Appendix B, page B-12 for

more information.)

Indicator Atmospheric deposition of nitrogen – Category 2 (continued)

2-32 2.2 Waters and Watersheds Chapter 2 - Purer Water

Nitrogen is a critical plant nutrient, and most nitrogen is used and

reused by plants within an ecosystem. Thus, in undisturbed

ecosystems, minimal “leakage” occurs into either surface runoff or

ground water, and concentrations are very low. However, when

amounts of nitrate in streams and ground water are elevated, this

generally indicates that inputs from human sources have increased

or that plants in the system are under stress. Elevated nitrogen

levels might come from fertilizer use, disposal of animal waste,

onsite septic systems, sewage treatment plants, or rain and snowfall (in the form of atmospheric deposition).

This indicator reports on the concentration of nitrate in streams

and ground water in farmland, forested, and urban areas.

Specifically, the indicator reports the percent of streams with

average nitrate concentrations in one of four ranges: less than

two ppm; two-six ppm; six-10 ppm; and 10 ppm or more. The

data, comprised of samples collected at over 100 stream sites in

farmland areas, were collected and analyzed by the NAWQA

program in 36 large watersheds across the U.S. during 1993

to1998. Thirty-six forested streams and 21 urban/suburban

streams also were evaluated. Ground water samples were collected from 20 to 30 private wells in each of 36 agricultural study

areas and 13 urban study areas.

What the Data Show

USGS data, compiled for The Heinz Center (2002), indicate that:

Q Nitrate concentrations were above two ppm (mg/L) in about

half of the stream sites and 55 percent of ground water wells

sampled in areas where agriculture is the primary land use

(Exhibit 2-19). 

Q Most nitrate concentrations in forested streams were less than

0.5 ppm (50 percent had concentrations of nitrate less than

0.1 ppm, 75 percent had concentrations of less than 0.5 ppm,

and only one had a concentration of more than 1.0 ppm).

Q Forty percent of urban/suburban streams had nitrate concentrations above 1.0 ppm (25 percent had concentrations below 0.5

ppm, and three percent had concentrations below 0.1 ppm).

About 20 percent of the ground water wells and about 10

percent of stream sites had concentrations that exceeded the

federal drinking water standard (10 mg/L). Only three percent of

urban ground water wells had nitrate concentrations exceeding the

standard. Samples of ground water in agricultural areas have

nitrate concentrations higher than ground waters of forested or

urban areas.

In four of 33 major drinking water aquifers sampled, the federal

drinking water standard for nitrate was exceeded in more than 

15 percent of samples collected. In these aquifers, all of which

underlie intensive agricultural areas, nitrate most often is elevated

in karst (carbonate) areas or where soils and aquifers consist of

sand and gravel. These natural features enable rapid infiltration

and downward movement of water and chemicals. Some of the

more vulnerable areas of the nation are the Central Valley of

California, and parts of the Pacific Northwest, the Great Plains,

and the Mid-Atlantic region. In contrast, contaminants are barely

detectable in ground water underlying farmland in parts of the

upper Midwest, despite similar high rates of chemical use. In these

areas, ground water contamination may be limited, because of the

relatively impermeable, poorly drained soils and glacial till that

cover much of the region, and because tile drains provide quick

pathways for runoff to streams (Gilliom, et al., 2002).

Nitrate contamination in shallow ground water (less than 100 feet

below land surface) raises potential concerns for human health,

Indicator Nitrate in farmland, forested, and urban streams and ground water – Category 2 
Technical Document Q EPA’s Draft Report on the Environment 2003

particularly in rural agricultural areas where shallow ground water is

used for domestic water supply. Furthermore, high levels of nitrate

in shallow ground water may serve as an early warning of possible

future contamination of older underlying ground water, which is a

common source for public water supplies (USGS, 1999).

Indicator Gaps and Limitations

These data only represent conditions in the 36 major river basins

and aquifers sampled by the NAWQA program. While they were

subjectively chosen to be representative of watersheds across the

U.S., they are the result of a targeted sample design.

The data also are highly aggregated and should only be

interpreted as an indication of national patterns. For example, the

definition of agricultural land included land use by cropland or

pasture. The percentage of land used for agricultural purposes

within specific watersheds varied from 10 to 99 percent of the

land cover, so the characterization of lands as agricultural is

subject to this degree of variation in land use.

Data Source

Data for this indicator were compiled for The Heinz Center

(2002) from the U.S. Geological Survey’s National Water

Quality Assessment Program. (See Appendix B, page B-13 for

more information.)

Indicator Nitrate in farmland, forested, and urban streams and ground water – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-33

Exhibit 2-19: Nitrates in farmland streams and ground water, 1992-1998

Nitrate in Farmland Streams Ecosystem Comparison: Nitrate in Streams, 1992-1998

Nitrate in Farmland Ground Water Ecosystem Comparison: Nitrate in Ground Water, 1992-1998

less than 2 ppm

2-6 ppm

6-10 ppm

10 ppm or more

less than 2 ppm

2-6 ppm

6-10 ppm

10 ppm or more

% of Stream Sites Tested

100

80

60

40

20

0

% of Stream Sites Tested

100

80

60

40

20

0

1992 - 1998 Farmlands Forests Urban % of Ground Water Sites Tested100

80

60

40

20

0

Farmlands Forests Urban

% of Ground Water Sites Tested100

80

60

40

20

0

1992 - 1998

Coverage: lower 48 states. Each sampling area was sampled intensively for approximately 2 years during 1992–1998.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the U.S. Geological Survey.
EPA’s Draft Report on the Environment 2003 Q Technical Document

Nitrogen in estuaries is commonly regarded as the most important

limiting nutrient. Nutrients can originate at either point sources

(e.g., sewage treatment plants and industries) or non-point

sources (e.g., farmlands, lawns, leaking septic systems, and the

atmosphere). Excess nutrients can lead to eutrophication.

Total nitrogen (TN) in the mid-Atlantic estuaries was calculated by

summing the concentrations of total dissolved nitrogen and

particulate organic nitrogen (EPA, ORD, May 2003). Assessment

categories were determined based on the 25th and 75th

percentiles. The categories are (EPA, ORD, May 2003): 

Q Low: < 0.5 ppm nitrogen 

Q Intermediate: 0.5 to 1.0 ppm nitrogen

Q High: > 1.0 ppm nitrogen

Currently there are no national-level water quality criteria for total

nitrogen in estuaries, but states are in the process of determining

nutrient criteria for their waters. 

What the Data Show

This analysis yielded the following results:

Q For the mid-Atlantic region, about 35 percent of the estuarine

area had low TN concentrations, 47 percent had intermediate

TN concentrations, and 18 percent had high TN concentrations

(Exhibit 2-20). 

Q About 50 percent of the mainstem area of the Chesapeake Bay

had low TN concentrations, with only about five percent having

high TN concentrations. 

Q In contrast, about fives percent of coastal bays had low TN concentrations, and about 35 percent had high TN concentrations. 

Q The entire Delaware River estuary portion of Delaware Bay had

high TN concentrations. 

Indicator Gaps and Limitations

These TN estimations for estuaries apply only to the mid-Atlantic

region and cannot be used to make national estimates of nitrogen

concentrations. 

Data Source

The data source for this indicator was EPA’s Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Program, part of 

EPA’s Environmental Monitoring and Assessment Program. 

(See Appendix B, page B-13, for more information.)

Indicator Total nitrogen in coastal waters – Category 2

2-34 2.2 Waters and Watersheds Chapter 2 - Purer Water

Exhibit 2-20: Extent of Mid-Atlantic estuaries with low, 

intermediate, and high total nitrogen concentrations, 

1997-1998

Intermediate

47%

Low

35%

High

18%

Source: EPA, Office of Research and Development. Mid-Atlantic Integrated 

Assessment, MAIA - Estuaries 1997-98, Summary Report. May 2003.
Technical Document Q EPA’s Draft Report on the Environment 2003

Phosphorus, an essential nutrient for all life forms, occurs naturally

in soils and aquatic systems. However, at high concentrations, phosphates, the most biologically active form of phosphorus, can cause

significant water quality problems by overstimulating algae growth.

This is both aesthetically unappealing and can contribute to the

loss of oxygen needed by fish and other animals. Human activity can

increase phosphorus levels through fertilizer use, disposal of animal

waste, sewage treatment, and use of some detergents.

This indicator reports on the concentration of phosphorus in

streams that drain watersheds comprised primarily of farmland,

forested, or urban land use. Specifically, the indicator reports the

percent of these streams that have average annual phosphorus 

concentrations in one of four ranges: less than 0.l ppm; 0.1 to 0.3

ppm; 0.3 to 0.5 ppm; and 0.5 ppm or more. Thirty-six forested

streams and 21 urban/suburban streams also were evaluated.

What the Data Show

Data compiled by the USGS indicate that: 

Q About three-fourths of farmland stream sites had concentrations of phosphorus above 0.1 parts per million (mg/L)

(Exhibit 2-21). 

Q About 15 percent of farmland stream sites had phosphorus

concentrations greater than 0.5 ppm of phosphorus. 

Q Phosphorus concentrations in streams of agricultural lands were

similar to but slightly higher than those in urban streams and

much greater than those in forest streams. 

EPA has recently set new regional water quality criteria for phosphorus levels in streams in agricultural ecosystems. These criteria

range from 0.023 to 0.076 ppm and vary according to differences

in ecoregions, soil types, climate, and land use.

Compared to nitrogen, a smaller proportion of phosphorus 

(originating mostly from livestock wastes or fertilizers) was lost from

watersheds to streams. The annual amounts of total phosphorus

measured in agricultural streams were equivalent to less than 

20 percent of the phosphorus that was applied annually to the

land. This is consistent with the general tendency of phosphorus to

attach to soil particles that move more slowly with runoff to surface

water. Even though less phosphorus is transported from land than

nitrogen, phosphorus is more likely to reach concentrations that 

can cause excessive aquatic plant growth. Nitrogen concentrations

are rarely low enough to limit aquatic plant growth in fresh water,

whereas phosphorus concentrations can be low enough to limit such

growth. Thus, adding phosphorus to an aquatic system can have a

greater impact than adding nitrogen. Hence, excessive aquatic plant

growth and eutrophication in fresh water generally result from elevated phosphorus concentrations (typically greater than 0.1 ppm)

(EPA, OW, June 1998). In contrast, nitrogen typically is the limiting

nutrient for aquatic plant growth in saltwater and coastal waters. 

Indicator Gaps and Limitations

These data only represent conditions in the 36 major river basins

and aquifers sampled by NAWQA. While they were subjectively

Indicator Phosphorus in farmland, forested, and urban streams – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-35

Exhibit 2-21: Phosphorus in farmland streams and ground water, 1992-1998

% of Stream Sites Tested

100

80

60

40

20

0

% of Stream Sites Tested

100

80

60

40

20

0

1992 - 1998 Farmlands Forests Urban/Suburban

Total Phosphorus in Farmland Streams Ecosystem Comparison: Total Phosphorus in Streams, 1995

less than 0.1 ppm

0.1 to 0.3 ppm

0.3 to 0.5 ppm

0.5 ppm or more

Coverage: lower 48 states. Each sampling area was sampled intensively for approximately 2 years during 1992–1998.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the U.S. Geological Survey.
EPA’s Draft Report on the Environment 2003 Q Technical Document

chosen to represent watersheds across the U.S., they are the

result of a targeted sample design.

The data also are highly aggregated and should only be interpreted as an indication of national patterns. For example, watersheds

dominated by agricultural land included land use by cropland or

pasture. The percentage of land used for these purposes varied

from 10 to 99 percent, so the characterization of lands as agricultural is subject to this degree of variation in land use.

Data Source

Data used for this indicator were compiled for The Heinz Center

(2002) from the U.S. Geological Survey’s National Water

Quality Assessment Program. (See Appendix B, page B-13, for

more information.)

Indicator Phosphorus in farmland, forested, and urban streams – Category 2 (continued)

2-36 2.2 Waters and Watersheds Chapter 2 - Purer Water

Increased phosphorus in large rivers and other waterbodies leads

to an increase in growth of algae. While small amounts of algae

provide the critical base of the food chains in these waterbodies,

larger amounts lead to eutrophication. As discussed in Section

2.2.3, eutrophication can lead to loss of oxygen, shifts in fish

population, and “nuisance blooms” of algal species. Algal blooms

generally degrade aesthetic and recreational values.

Data on phosphorus were collected from 140 sites in large rivers

(i.e., rivers with flows exceeding 1,000 cubic feet per second) at

least 30 times over a 2-year period between 1992 and 1998 by

the USGS (The Heinz Center, 2002).

What the Data Show

Half of the rivers tested had total phosphorus concentrations

equaling or exceeding 100 parts per billion (The Heinz Center,

2002) (Exhibit 2-22), which is EPA’s recommended goal for preventing excess algal growth in streams that do not flow directly

into lakes. None of the rivers had concentrations below 20 parts

per billion, a level generally held to be free of negative effects

(EPA, OW, November 1986).

Indicator Gaps and Limitations

Phosphorus measurements in rivers were restricted to those large

rivers with flows exceeding 1,000 cubic feet per second. To

ensure proper characterization of average values for each river,

only sites that had at least 30 samples over the course of 2 years

were included. Thus, only large rivers with adequate sampling are

represented.

The data used for this indicator are from larger rivers. Larger rivers

typically have both larger discharge volumes and watersheds with

more diverse land uses. These samples, therefore, represent the

integrating influences of many different land uses. Also, they were

the result of a targeted sample design, and may not be representative of large rivers across the U.S.

Data Source

The data used for this indicator were from the U.S. Geological

Survey as compiled for The Heinz Center (2002). (See Appendix

B, page B-14, for more information.)

Indicator Phosphorus in large rivers – Category 2

Exhibit 2-22: Distribution of phosphorus 

concentrations in large rivers, 1991-1996

100

80

60

40

20

0

1991 to 1996

Percent of Tested Sites with Indicated Total 

Phosphorus Concentrations

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Geological Survey.

Coverage: lower 48 states

Note: 140 sites were tested. (ppb = parts per billion)

20 to 50 ppb 50 to 100 ppb

100 ppb or greater
Technical Document Q EPA’s Draft Report on the Environment 2003

Phosphorus is an essential plant nutrient. It is derived from

weathering and erosion of natural mineral deposits, runoff of fertilizers applied to agricultural and urban areas, and point source

discharges of sewage, detergents, pharmaceuticals, and other

phosphorus-containing products. Phosphorus is generally 

considered the limiting nutrient in fresh water systems (Schindler,

1977), but it can also become limiting in estuarine areas if total

nitrogen becomes abundant (EPA, ORD, May 2003).

Total phosphorus data were collected in the mid-Atlantic 

estuaries (EPA, ORD, May 2003) during 1997 and 1998. TP

assessment categories were based on the 25th and 75th percentile concentrations measured throughout the mid-Atlantic

region. These categories are:

Q Low: <0.05 to 0.1 ppm

Q Intermediate: 0.05 to 0.1 ppm

Q High: >0.1 ppm

What the Data Show

Analysis of the data showed that:

Q TP concentrations in mid-Atlantic estuaries ranged from 0 to

0.34 ppm.

Q For the mid-Atlantic region, about 58 percent of the estuarine

area had low TP concentrations, 30 percent had intermediate

TP concentrations, and 12 percent had high TP concentrations

(Exhibit 2- 23).

Q About 85 percent of the mainstem area of Chesapeake Bay had

low TP concentration with no areas having high TP concentrations.

Q The coastal bays, in contrast, had no areas with low TP concentrations and about 35 percent with high TP concentrations.

Q The Delaware River estuary portion of Delaware Bay had 

100 percent of its area with high TP concentrations.

Indicator Gaps and Limitations

These TP estimations apply only to estuaries of the mid-Atlantic

region and cannot be used to make national estimates of phosphorus concentrations.

Data Source

Data for this indicator came from EPA’s Environmental Monitoring

and Assessment Program, Mid-Atlantic Integrated Assessment

(MAIA) Estuaries Program. (See Appendix B, page B-14, for more

information.)

Indicator Total phosphorus in coastal waters – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-37

Exhibit 2-23: Extent of Mid-Atlantic estuaries with low, 

intermediate, and high total phosphorus concentrations, 

1997-1998

Intermediate

30%

Low

58%

High

12%

Source: EPA, Office of Research and Development. Mid-Atlantic Integrated 

Assessment, MAIA - Estuaries 1997-98, Summary Report. May 2003.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-38 2.2 Waters and Watersheds Chapter 2 - Purer Water

2.2.4.c Chemical Contaminant Pressures

The waters of our rivers, lakes, and oceans have been contaminated

by pollutants. Some of these pollutants, such as the pesticide DDT

and the industrial chemicals known as PCBs, were released into the

environment long ago. The use of DDT and PCBs in the U.S. was

banned in the 1970s, but these chemicals persist for many years.

Other contaminants enter our waters every day. Some flow directly

from industrial and municipal waste dischargers, while others come

from non-point source pollution in urban and agricultural areas.

Additionally, other contaminants are carried through the air and

eventually are deposited on lands and in lakes and streams far from

the facilities that produced them. When this happens, sediments in

waterbodies may serve as a reservoir for these contaminants and,

ultimately, as a source of contamination. 

The USGS has compiled contaminant data for waterbodies as part of

its National Water Quality Assessment Program. Gilliom, et al.

(2002) summarized some of major NAWQA findings as follows:

Q Detectable concentrations of pesticides were widespread in agricultural area streams. DDT was the most commonly detected

organochlorine compound, followed by dieldrin and chlordane.

Q Water in urban areas has a characteristic “signature” that is reflective of the chemicals used in the watersheds. Insecticides—such as

diazinon, carbaryl, cholorpyrifos, and malathion—were detected

more frequently and usually at higher concentrations in urban

streams than in agricultural streams.

Q Concentrations of selected trace elements, such as cadmium, lead,

zinc, and mercury, are elevated above background levels in heavily

populated urban settings.

Q Volatile organic compounds (VOCs), which are used in plastics,

cleaning solvents, gasoline, and industrial operations, are prevalent

in shallow urban ground water.

Eight indicators have been chosen to describe chemical contaminant

pressures on water resources:

Q Atmospheric deposition of mercury.

Q Chemical contamination in streams and ground water.

Q Pesticides in farmland streams and ground water.

Q Acid sensitivity in lakes and streams.

Q Toxic releases to water of mercury, dioxin, lead, PCBs, and persistent bioaccumulative toxic chemicals (PBTs).

Q Sediment contamination of inland waters.

Q Sediment contamination of coastal waters.

Q Sediment toxicity in estuaries.

Mercury contamination of waters and sediments is one of the leading causes of closed fisheries and fish consumption advisories in

the U.S. (see Section 2.5). Atmospheric deposition in the Great

Lakes and northeastern area of the U.S. is the primary source of

this contaminant. Discharges to waterways as indicated by data

from EPA’s Toxics Release Inventory (TRI) are a relatively small

source of mercury contamination.

The EPA National Sediment Inventory (NSI) has extensively reviewed

sediment quality data collected predominantly from sampling programs

targeted at sites of known contamination (see <http://www.epa.gov/

waterscience/basins/metadata/nsi.htm>). NSI classifies these sites as

demonstrating, by association or otherwise, probable biological effects

related to the contamination. Not surprisingly, the most contaminated

watersheds are found in the Great Lakes region and northeast corridor

in areas of dense populations and industrial development. Data show

that a small proportion (1 percent or less) of the sampled estuarine

areas of the eastern U.S. and Gulf of Mexico coasts contain chemicals

at concentrations high enough to be associated with biological effects.

The primary sources of mercury emissions on a national level are

coal-fired power plants (33 percent), municipal waste incinerators

(18 percent), and medical waste incinerators (10 percent) 

(EPA, OW, December 1997). Coal-fired power plants produce

mercury by burning coal, which contains trace amounts of 

mercury that are released during combustion. Incinerators emit

mercury when they burn wastes containing mercury. For medical

waste incinerators, mercury waste comes from medical devices like

thermometers and blood pressure cuffs. For municipal waste

incinerators, mercury comes from discarded appliances, such as

thermostats and fluorescent lights and lamps.

Mercury deposition was estimated from measurements made by

the Mercury Deposition Network (MDN), which is part of the

National Atmospheric Deposition Program. Precipitation samples

were collected weekly and analyzed for total mercury and

methylmercury. The MDN began a transition network of 13 sites in

1995 and, in the next year, became an official network in the NADP

with 26 sites. During 2000, more than 50 sites were in operation.

Indicator Atmospheric deposition of mercury – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

What the Data Show

Estimates of annual mercury wet deposition in 2001 are 

presented in Exhibit 2-24. Mercury deposition ranges from a low of

2.4 micrograms per square meter (μg/m2) measured at a California

site to over 14 μg/m2 at sites in eastern Texas, south Florida, and

eastern Wisconsin. The Great Lakes and southeastern states are

those most greatly affected by mercury deposition.

Indicator Gaps and Limitations

Limitations for this indicator include:

Q The spatial coverage provided by the Mercury Deposition

Network is somewhat limited, though the measurement sites

have been distributed relative to major mercury emission

sources.

Q Only wet deposition of mercury was measured.

Data Source

The interagency National Atmospheric Deposition Program served

as the data source for this indicator. (See Appendix B, page B-14,

for more information.)

Indicator Atmospheric deposition of mercury – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-39

9.3

7.2

12.1

7.2

7.7

8.0

7.9

13.0

9.0

15.7 18.9

16.8

14.4

13.1

14.1

21.0

21.1

18.0

9.0

9.3

6.1

9.5

11.4

4.9

8.3

6.3

4.9

4.0

5.3

5.0

7.5

5.9

2.7

14.2 11.3

11.0

12.1

11.9

12.6

16.2 15.7

6.8

7.4

8.5

9.8

12.3

Exhibit 2-24: Annual mercury wet deposition in 2001

per square meter (μg/m2)

Note: Coverage does include Alaska, Hawaii, or Puerto Rico

Source: National Atmospheric Deposition Program, Mercury Deposition Network. 2001. 

March 25, 2003; (http://nadp.sws.uiuc.edu/mdn/maps/2001/01MDNdepo.pdf).
EPA’s Draft Report on the Environment 2003 Q Technical Document

The U.S. Geological Survey reported on contaminants in stream

waters and streambed sediment for the entire U.S. (see The Heinz

Center, 2002). The contaminants reported include many pesticides,

selected pesticide degradation products, PCBs, polyaromatic hydrocarbons (PAHs), volatile organic compounds, other industrial contaminants, and trace elements. In sufficient concentrations, any of

these chemicals can harm wildlife, but for many of these compounds, there are no standards or guidelines for acceptable levels in

aquatic systems.

In the USGS analysis, water contaminant data were derived from

36 major river basins, which included 109 stream sites with data

sufficient to calculate annual averages. Stream water samples generally were collected on 20 to 40 occasions over a one-year period (Gilliom, et al., 2002) during 1992 to 1998. Ground water

data were collected from 3,549 wells in these major river basins

and aquifers.

What the Data Show

All stream waters averaged one or more contaminants at

detectable levels throughout the year. More than 80 percent 

averaged five or more (Exhibit 2-25). About 90 percent of 

ground water sites averaged one or more detectable contaminants.

40 percent contained five or more contaminants.

Indicator Gaps and Limitations

The sites sampled are representative of a wide range of stream

sizes, types, and land uses broadly distributed across the U.S.

(Gilliom, et al., 2002; The Heinz Center, 2002).

Data Source

Date for this indicator came from U.S. Geological Survey, as compiled for The Heinz Center (2002). (See Appendix B, page B-15,

for more information.)

Indicator Chemical contamination in streams and ground water – Category 2

2-40 2.2 Waters and Watersheds Chapter 2 - Purer Water

Exhibit 2-25: Occurrence of contaminants in 

streams and ground water, 1992-1998

100

80

60

40

20

0

1992 to 1998 1992 to 1998

Percent of Sites with Indicated Number of

Contaminants Detected

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Geological Survey.

Coverage: lower 48 states.

Streams

Ground water

1 or 2

3 or 4

5 or more

Nearly one billion pounds of pesticides are used in the U.S. each

year to control weeds, insects, and other organisms that threaten

or undermine human activities such as agriculture. The vast

majority of pesticides—about 80 percent—are used for agricultural purposes. Although pesticide use has resulted in increased

crop production and other benefits, it has also raised concerns

about potential adverse effects on the environment and human

health. Pesticide contamination of streams, rivers, lakes, reservoirs, coastal areas, and ground water may cause unintended

adverse effects. These water resources support aquatic life and

related food chains and are used for recreation, drinking water,

irrigation, and many other purposes. In addition, water is one of

the primary pathways by which pesticides are transported from

their application areas to other parts of the environment. 

Indicator Pesticides in farmland streams and ground water – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

From 1992 to 1998, the USGS, under its National Water Quality

Assessment Program, conducted the largest data collection effort

ever performed for pesticides (including insecticides and herbicides) in ground and surface waters. This effort involved analysis

for 76 pesticides and seven selected pesticide degradation products in 8,200 samples of ground water/surface water in 20 of the

nation’s major hydrologic basins. Sampling sites included streams

and ground water in both agricultural areas and urban areas.

What the Data Show

In all streams, at least one pesticide was present at detectable

levels throughout the year. Data were analyzed separately for

agricultural and urban areas:

Q Agricultural areas. About 75 percent of monitored farmland

streams had an average of five or more pesticides at detectable

levels, and over 80 percent had at least one pesticide that

exceeded aquatic life guidelines. About 60 percent of ground

water sites in agricultural areas had a least one detectable 

pesticide, and seven percent had an average of five or more 

compounds at detectable levels. A very small proportion (less

than one percent) of ground water sites in farmland areas had

one or more pesticides in concentrations that exceeded human

health standards or guidelines (The Heinz Center, 2002). A 

relatively small number of these chemicals—specifically the 

herbicides atrazine (and its breakdown product desethylatrazine),

metolachlor, cyanazine, and alachlor—accounted for most 

detections in ground water. The high detection frequency for

these pesticides is related to their use. All are among the top 

five herbicides used in agriculture across the nation (Gilliom, 

et al., 2002).

Q Urban areas. Water in urban areas has a characteristic “signature” that is reflective of the chemicals used in the watersheds

serving those areas. Insecticides such as diazinon, carbaryl,

chlorpyrifos, and malathion were detected more frequently, and

usually at higher concentrations, in urban streams than in agricultural streams. Herbicides were detected in 99 percent of

urban stream samples and in more than 50 percent of sampled

wells. The most common herbicides in urban streams and

ground water were simazine and prometon.

Frequency of detection, expressed as a percentage of pesticides in

water samples, serves as a basic indicator (Exhibit 2-26):

Q Streams. The data suggest that pesticides are fairly ubiquitous

in both farmland and urban streams and rivers. As noted above,

at least one pesticide was present at detectable levels throughout the year in all monitored streams. Most pesticide detections were found in rivers associated with mixed land uses, followed by streams associated with urban land use, then streams

associated with agricultural land uses.

Q Ground water. Significantly fewer detections of pesticides were

found in shallow ground water, and the least detections were

found in major aquifers.

For the 21 most detected pesticides, data suggest that their

occurrence, in both streams and ground water, closely mirrors

their use. Surprisingly, pesticides were detected as frequently, or

sometimes more frequently, in urban streams than in streams

associated with agricultural lands. The NAWQA data indicate that,

in urban and agricultural streams and shallow ground water, pesticides most often occur in mixtures (i.e., more than one compound

is present in the sample). The human health and environmental

impacts of pesticide contamination, particularly when the pesticides occur as mixtures, are not well understood.

Data Gaps and Limitations

Knowing how many pesticides are detected and at what concentrations provides basic information on the extent to which these

compounds are found in streams and ground water. However, the

presences of pesticides does not necessarily mean that the levels

Indicator Pesticides in farmland streams and ground water – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-41

Coverage: lower 48 states

Source: Modified from The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Geological Survey.

100

90

80

70

60

50

40

30

20

10

0

Streams Shallow Shallow

GW

Streams Major

Aquifers

Rivers

Agricultural Urban Mixed Land Use

Frequency of detection, as percentage of samples

Exhibit 2-26: Summary of detections of one or more 

pesticides in streams and ground water, 1992-1998

GW
EPA’s Draft Report on the Environment 2003 Q Technical Document

are high enough to cause problems. Comparison to standards and

guidelines provides a useful reference to help judge the significance of contamination.

Drinking water standards or guidelines do not exist for 43 percent

(33 of 76) of the pesticides analyzed, and aquatic life guidelines

do not exist for 63 percent (48 of 76) of the pesticides analyzed.

Current standards and guidelines do not account for mixtures of

chemicals and seasonal pulses of high concentrations. In addition,

potential effects on reproductive, nervous, and immune systems,

as well as on chemically sensitive individuals, are not yet well

understood.

Data Sources

The data sources for this indicator were The U.S. Geological

Survey’s National Water Quality Assessment Program, as compiled

for The Heinz Center (2002), and The EPA’s Office of Prevention,

Pesticides, and Toxic Substances.(See Appendix B, page B-15, for

more information.)

Indicator Pesticides in farmland streams and ground water – Category 2 (continued)

2-42 2.2 Waters and Watersheds Chapter 2 - Purer Water

Airborne nitrogen and sulfur gases (i.e., nitrogen oxides and sulfur

oxides) are referred to as acid precursors because they react with

water, oxygen, and other compounds to form sulfuric acid and

nitric acid. For example:

Q They combine with water vapor and oxygen in the atmosphere

to form acids that fall to earth as a component of snow, fog,

dry particles, gases, or acid rain. 

Q When they reach a waterbody through dry deposition, they

combine with surface water to form nitric acid and sulfuric acid. 

Q Indirect deposition can occur when these precursors are

deposited on land and then washed into a waterbody by storm

water runoff. The effects of indirect deposition are particularly

serious if the storm deposits acid rain. 

Acidification is common in waterbodies in the eastern U.S., where

weather patterns deposit acids made from air pollutants generated

in the Midwest and points further west. Also, many eastern waterbodies are naturally acidic, making them more susceptible to the

effects of acid deposition because their underlying soils and rock

are not able to buffer incoming acids. This is particularly true for

many lakes in the Adirondack Park, located in upstate New York. 

Acidification affects ecosystems in many ways. For example:

Q Aquatic organisms in acidified waters often suffer from calcium

deficiencies that can weaken bones and exoskeletons and can

cause eggs to be weak or brittle. 

Q It affects the permeability of fish membranes and, particularly,

the ability of gills to take in oxygen from water. 

Q Increasing amounts of acid in a waterbody change the mobility

of certain trace metals like aluminum, cadmium, manganese,

iron, arsenic, and mercury. Species that are sensitive to these

metals, particularly fish, can suffer as a result.

Acid sensitivity in lakes and streams is determined based on a

suite of chemical measurements, including pH, conductivity, dissolved organic carbon (DOC), cations, anions, and acid-neutralizing capacity (ANC). Using data for these parameters, it is possible

to distinguish, on a national scale, natural sources of acidity such

as wetlands, from anthropogenic sources such as acid deposition

and mine drainage (Baker, et al., 1991). For example, in low pH

waters:

Q High conductivity and high sulfate concentrations indicate acidmine drainage.

Q High DOC concentrations with low conductivity indicate acid

contributions from wetlands.

Q Low conductivity, moderate sulfate concentrations, and low

DOC concentrations indicate acid deposition.

What the Data Show

EPA’s 1984 to 1986 National Surface Water Survey (NSWS) estimated that, in acid-sensitive regions of the northern and eastern

Indicator Acid sensitivity in lakes and streams – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

U.S., 4.2 percent of lakes and 2.7 percent of streams were acidic.

Of those acidic lakes and streams, 75 percent were acidic due 

to acid deposition, 22 percent were acidic due to organic 

sources, and three percent were acidic due to acid-mine drainage

(Exhibit 2-27).

These surveys have been repeated periodically for smaller probability samples of lakes in the Northeast, the Adirondacks and

streams in the Appalachians (Stoddard, et al., 1996). More intensive monitoring also has been conducted on lakes in the

Northeast, the Appalachians, and the Midwest, and on streams in

the Appalachian Plateau and Blue Ridge to assess long-term acidification trends (Stoddard, et al., 1998). Based on these programs,

EPA estimated that in three regions, one-quarter to one-third of

lakes and streams previously affected by acid rain were no longer

acidic, although they were still highly sensitive to future changes

in deposition (EPA, ORD, January 2003). EPA has concluded that

the decrease in acidity is a result of reduced sulfate emissions

under its acid rain programs. Specifically:

Q Eight percent of lakes in the Adirondacks are currently acidic,

down from 13 percent in the early 1990s.

Q Less than two percent of lakes in the upper Midwest are currently acidic, down from three percent in the early 1980s.

Q Nine percent of the stream length in the northern Appalachian

plateau region is currently acidic, down from 12 percent in the

early 1990s.

Lakes in New England did not show decreases in acidity, and

streams in the Ridge and Blue Ridge regions of Virginia were

unchanged. Even though acid deposition has been decreasing in

the Ridge and Blue Ridge regions, waterbodies in these areas are

expected to show a lag time in their recovery due to the nature of

the soils in those regions. Immediate responses to decreasing

deposition were neither seen nor expected in these two regions.

Indicator Gaps and Limitations

The NSWS has not been repeated nationwide since the mid1980s, so there are no data to assess trends in surface water

acidification in other sensitive areas of the country.

Data Source

The data source for this indicator was EPA’s National Surface

Water Survey. (See Appendix B, page B-15, for more information.)

Indicator Acid sensitivity in lakes and streams – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-43

Exhibit 2-27: Sources of acidity in acid-sensitive 

 lakes and streams, 1984-1986

Organic 

deposition

22%

Acid 

deposition

75%

Watershed 

sources 3%

Coverage: Acid sensitive regions of the United States north and east, inclusive 

of the upper midwest, New England, Adirondack Mountains in New York, the 

northern Appalachian Plateau, and the Ridge and Blue Ridge Provinces of 

Virginia

Source: Baker et al. Acid Lakes and Streams in the United States: The Role of 

Acidic Deposition. (1991).
EPA’s Draft Report on the Environment 2003 Q Technical Document

The Toxics Release Inventory (TRI) contains information on toxic

chemical releases and other waste management activities reported

annually by certain industries as well as by federal facilities. This

inventory was established under the Emergency Planning and

Community Right-to-Know Act of 1986 (EPCRA), which requires

facilities to use their best readily available data to calculate their

releases and other waste management estimates. This indicator is

based on reported TRI releases of mercury, dioxins, PCBs, sum of

all persistent bioaccumulative toxic chemicals (PBTs), and lead to

water in calendar year 2000 (EPA, OEI, May 2002).

PBT chemicals include dioxins, mercury, PCBs, PAHs, and pesticides (but not lead). PBT pollutants are chemicals that are toxic,

persist in the environment, and bioaccumulate in food chains, thus

posing risks to human health and ecosystems. They transfer easily

across and among ecological systems.

Under EPCRA, most dischargers must report releases of toxic

chemicals. Specifically, a facility must report to TRI if it meets all

of the following criteria:

Q Conducts manufacturing operations within Standard Industrial

Classification (SIC) codes 20 through 39 or, beginning in the

1998 reporting year, is in one of the following industry categories: metal mining, coal mining, electric utilities that combust

coal and/or oil, chemical wholesale distributors, petroleum terminals, bulk storage facilities, Resource Conservation and

Recovery Act (RCRA) subtitle C hazardous waste treatment

and disposal facilities, and solvent recovery services. Also, federal facilities must report to TRI regardless of their SIC code

classification.

Q Has 10 or more full-time employee equivalents.

Q For all but certain PBT chemicals, manufacturers or processes

more than 25,000 pounds or otherwise uses more than

10,000 pounds of any listed chemical during the calendar year.

What the Data Show

During 2000, facilities reporting to the TRI released over 7 billion

pounds of chemicals (EPA, OEI, May 2002). Of that total, nearly

261 million pounds (3.7 percent) were discharged to water,

including 21,318 pounds of PBTs, 29 pounds of PCBs, 5 pounds

of dioxin compounds, and 2,302 pounds of mercury compounds.

(Note that the total for PBTs includes all PBT compounds reported under TRI. Total releases for specific types of PBT compounds,

such as PCBs and mercury compounds, are also aggregated and

reported separately.) 

Indicator Gaps and Limitations

The TRI data have several limitations:

Q The TRI program only accounts for direct releases to water (i.e.,

it does not include releases from non-point sources). However,

it does identify releases of metal and metal compounds from

publicly owned treatment works (POTWs).

Q It does not include releases below the reporting thresholds.

Q Reporting is made by the releasing facilities, and no standard

estimation procedure is employed (see Chapter 3–Better

Protected Land).

Data Source

The data source for this indicator is EPA’s Toxics Release Inventory

program. (See Appendix B, page B-15, for more information.)

Indicator Toxic releases to water of mercury, dioxin, lead, PCBs, and PBTs – Category 2

2-44 2.2 Waters and Watersheds Chapter 2 - Purer Water
Technical Document Q EPA’s Draft Report on the Environment 2003

Contaminated sediments generally have localized impacts, with the

severity of impact depending on the degree of chemical contamination. Contaminated sediments affect benthic organisms, such as

worms, crustaceans, and insect larvae that inhabit the bottom of

waterbodies. In some cases, toxic sediments kill these benthic

organisms, reducing the food available to larger animals such as

fish. Also, some contaminants in sediments may be taken up by

benthic organisms and passed onto larger animals that feed on

these contaminated organisms. In this way, toxins in sediment

move up the food chain in increasing concentrations. As a result,

fish and shellfish, waterfowl, and fresh water and marine animals,

as well as benthic organisms, may be affected by contaminated

sediments.

As part of EPA’s National Sediment Inventory (described in the

introduction to Section 2.2.4c), sediment chemical concentrations were evaluated in over 19,000 samples in the U.S. and categorized into three groups:

Q Tier 1 (associated adverse effects on aquatic life or human

health are probable).

Q Tier 2 (associated adverse effects on aquatic life or human

health are possible).

Q Tier 3 (no indication of associated adverse effects on aquatic

life or human health).

Tier 1 sampling stations were distinguished from Tier 2 sampling

stations based on the magnitude of a contaminant concentration

in sediment, or the degree of corroboration among the different

types of sediment quality measures.

What the Data Show

Of the sampling stations evaluated, 8,348 stations (43 percent)

were classified as Tier 1, 5,846 (30.1 percent) were classified as

Tier 2, and 5,204 (26.8 percent) were classified as Tier 3. The

sampling stations were located in 5,695 individual river reaches

(or waterbody segments) across the conterminous U.S., which

constitute approximately 8.8 percent of all river reaches in the

country (based on EPA’s River Reach File 1).

Q Approximately 3.6 percent of all river reaches in the conterminous U.S. had at least one station categorized as Tier 1.

Q Approximately 3 percent of reaches had at least one station

categorized as Tier 2 (but none as Tier 1).

Q In about 2.3 percent of reaches, all of the sampling stations

were classified as Tier 3.

In the National Sediment Inventory, watersheds (8-digit HUC)

containing areas of probable concern (APCs) for sediment contamination were defined as those that include at least 10 Tier 1

sampling stations and in which at least 75 percent of all sampling

stations were classified as either Tier 1 or Tier 2. APC designation

could result from extensive sampling throughout a watershed, or

from intensive sampling at a single contaminated location or a few

contaminated locations. 

Analysis of survey data showed that:

Q Ninety-six eight-digit HUC watersheds were identified as containing APCs (Exhibit 2-28).

Q These watersheds represent about 4.2 percent of all eight-digit

HUC watersheds in the U.S. (96 of 2,264).

Q In many of these watersheds, contaminated areas may be concentrated in specific river reaches in the watershed. For example,

within the 96 watersheds containing APCs across the country,

97 individual river reaches or waterbody segments have 10 or

more Tier 1 sampling stations.

Q Twenty-four percent of reaches in watersheds (eight-digit HUC)

containing APCs have at least one Tier 1 sampling station and

18.3 percent have no Tier 1 sampling station but at least one

Tier 2 sampling station.

The evaluation results indicate that sediment contamination associated with probable or possible adverse effects for both aquatic

life and human health exists in a number of watersheds across the

country.

Indicator Gaps and Limitations

Two general types of limitations are associated with the National

Sediment Inventory:

Q Limitations of the compiled data. These limitations include the

mixture of data sets derived from different sampling strategies,

incomplete sampling coverage of geographic regions and monitored chemicals, the age and quality of the data, and the lack of

measurements of important assessment parameters, such as

TOC and acid volatile sulfide.

Q Limitations of the evaluation approach. These include uncertainties in the interpretive tools used to assess the sediment 

quality, use of assumed exposure potential in screening-level

quantitative risk assessment (e.g., fish consumption rates as a

surrogate for human health risk), and the subsequent difficulties in interpreting assessment results. Also, because this

analysis is based only on readily electronically formatted data,

the survey does not include a vast amount of information

available from sources such as local and state governments and

published academic studies.

Indicator Sediment contamination of inland waters – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-45
EPA’s Draft Report on the Environment 2003 Q Technical Document

Another key limitation is that most of the NSI data were compiled

from monitoring programs that focus their sampling efforts on

areas where contamination is known or suspected to occur. While

this is important for meeting the stated objective of the NSI survey, which is to identify contaminated sediments, it means that

the data cannot be used to accurately characterize the overall

condition of the nation’s sediment, because national sampling

coverage is incomplete and because uncontaminated areas are

most likely substantially under-represented. In addition, the data

analyzed for this indicator were collected over a relatively long

time period; therefore, they do not definitively assess the current

condition of sediments, but can serve as a baseline for future

assessments.

Data Source

The data are described in Appendix A of the draft report The

Incidence and Severity of Sediment Contamination in Surface Waters

of the U.S., National Sediment Quality Survey; second edition (EPA822-R-01-01). A draft is available. The final report is expected to

be released in 2003. Summary reports on the data are not available. (See Appendix B, page B-15, for more information).

Indicator Sediment contamination of inland waters – Category 2 (continued)

2-46 2.2 Waters and Watersheds Chapter 2 - Purer Water

Source: EPA, Office of Water. The Incidence and Severity of Sediment Contamination in Surface Waters of the United States, National Sediment Quality 

Survey: Second Edition, Draft. December, 2001.

Exhibit 2-28: Watersheds in sediment quality inventory (1980-1999) identified as containing areas of 

particular concern (APCs)
Technical Document Q EPA’s Draft Report on the Environment 2003

Estuaries are important habitats for migratory birds, and many

species of fish and shellfish rely on the sheltered waters of estuaries

as protected places to spawn. Contamination of sediments in estuaries can pose a threat to individual species and to estuarine

ecosystems. 

Contaminated sediments may harm benthic organisms that feed

on these sediments, and they may accumulate up the food chain

as larger organisms feed on smaller organisms, eventually posing a

risk to human health. Additionally, contaminants in sediments may

be resuspended into the water by dredging and boating activities.

One of the challenges of assessing sediment contamination is 

distinguishing among naturally occurring contaminants, such as

certain organics and metals, from those created by human 

activities. PAHs and metals occur naturally in estuarine sediments,

so a special approach must be used to determine how much of

their concentrations in sediment are contributed by human

sources (Windom, et al., 1989). On the other hand, pesticides

and PCBs are relatively easy to evaluate, as they can only come

from human activities.

Under the EPA’s Environmental Monitoring and Assessment

Program (EMAP), contamination was measured for sediments from

estuaries in the Virginian, Carolinian, and Louisianian Provinces of

the eastern U.S. Chemical concentrations were identified as

enriched by human sources if they exceeded values expected to

occur naturally. Sediment chemical concentrations also were compared to NOAA-derived effects range low (ERL) values and effects

range median (ERM) values. These values identify threshold concentrations that, if exceeded, are expected to produce ecological

or biological effects 10 percent and 50 percent of the time,

respectively. A site was considered contaminated if five or more

chemical concentrations exceeded the ERL, or if one or more

exceeded the ERM.

What the Data Show

Sediment contaminant concentrations indicate that 40 percent,

45 percent, and 75 percent of U.S. estuarine sediments that were

sampled are enriched with metals from human sources, PCBs, and

pesticides, respectively (Exhibit 2-29).

One to two percent of estuarine sediments show concentrations

of contaminants (PAHs, PCBs, pesticides, and metals) that are

above ERM values (Exhibit 2-30). Between 10 and 29 percent of

sediments have contaminant concentrations between the ERM values and lower-level ERL values (Exhibit 2-30). Most of the locations exceeding the ERM guidelines are in the northeast coastal

area, while the Gulf of Mexico coast contains many locations

where concentrations of five or more contaminants exceed the

ERL values. The highest contamination is found in the Northeast.

Estuaries most affected are: Hudson River-New York, New Jersey

Harbor system; eastern Long Island Sound; Delaware River;

Potomac River; and upper Chesapeake Bay.

Indicator Gaps and Limitations

Several limitations are associated with this indicator:

Q Assessment of contamination is limited to the three provinces

noted above. Probabilistic assessments of coastal waters of the

Great Lakes, West Coast, and northern New England do not

exist, so this indicator does not include data for these regions.

Q The sampling design did not proportionately represent shallow

habitats (less than 3 meters), which may represent as much as

50 percent of the total estuarine area in the Southeast and

Gulf of Mexico.

Q While the data currently are adequate to address regional condition, they provide little information on gradients from major

sources of contamination (e.g., large urban areas).

Q Many factors control availability of contaminants in sediments,

including organic content, acid volatile sulfides, pH, particle size

and type, and the specific form of chemical (e.g., chromium).

Therefore, sediment chemical concentrations, in and of themselves, do not directly estimate the biological availability of

those contaminants.

Indicator Sediment contamination of coastal waters – Category 2

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-47

40

46

34

53

29

40

45

63

11

99

28

46

75

77

59

93

75

82

0 20 40 60 80 100 120

U.S.

MidAtlantic

Southeast

South 

Florida

Gulf of 

Mexico

Southern 

California

Percent Area

Metals

PCBs

Pesticides

Exhibit 2-29: Regional sediment enrichment (1990-1997) 

due to human sources

Source: EPA, Office of Research and Development and Office of Water. National 

Coastal Condition Report. September 2001.
EPA’s Draft Report on the Environment 2003 Q Technical Document

Q The scientific basis for the ERL/ERM criteria may vary among

estuaries, habitats, and regions depending upon the kinds and

abundances of indigenous biota. 

Q Sediment contamination is not directly related to the biological

availability of contaminants in sediments. Bioavailability of contaminants in sediments can be directly measured by sediment

toxicity testing, which forms the basis for the next indicator discussed, “sediment toxicity in estuaries.”

Data Source

Sediment contamination data are from the EPA’s Environmental

Monitoring and Assessment Program Estuaries dataset. 

(See Appendix B, page B-16, for more information.)

Indicator Sediment contamination of coastal waters – Category 2 (continued)

2-48 2.2 Waters and Watersheds Chapter 2 - Purer Water

1% > ERM

29% 

between

ERL and ERM

70% < ERL

1% > ERM

23% 

between

ERL and ERM

76% < ERL

1% > ERM

10% 

between ERL 

and ERM

89% < ERL

Below Levels Associated with Adverse Affects Effects Possible But Unlikely Effects likely 

Contaminant Concentrations with Adverse Effects on Organisms

Coverage: United States east coast (excluding waters north of Cape Cod) and Gulf of Mexico

Source: EPA, Office of Research and Development and Office of Water. National Coastal Condition Report. September 2001.

Pesticides Metals PAHs/PCBs

Exhibit 2-30: Distribution of sediment contaminant concentrations in sampled estuarine sites, 1990 - 1997

Many factors control the biological availability of contaminants in

sediments, including acid volatile sulfides, pH, particle size and

type, organic content, resuspension potential, and specific

species/form of contaminant (e.g., chromium). Sediment toxicity

tests are the most direct current measure for determining the

bioavailability of contaminants in sediments. These tests provide

information that is independent of chemical characterization and

ecological surveys (Chapman, et al., 1987). They improve upon

the direct measure of contaminants in sediments (the basis for

the previous indicator “sediment contamination of coastal

waters”), because many contaminants are tightly bound to sediment particles or are chemically complex and are not biologically

available. Thus, the presence of contaminants in sediments does

not necessarily mean that the sediments are toxic.

To assess bioavailability of sediment contaminants in estuaries, the

EPA’s EMAP Estuaries Program, in conjunction with the NOAA

Status and Trends Program, conducted sediment toxicity tests on

estuarine sediments.

What the Data Show

The EPA’s EMAP Estuaries Program found that about 10 percent

of the sediments in estuaries in the Virginian, Carolinian,

Louisianian, West Indian, and Californian Provinces were toxic to

Indicator Sediment toxicity in estuaries – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

the marine amphipod, Ampelisca abdita, over a 10-day period

(EPA, ORD, OW, September 2001). The NOAA Status and Trends

Program also used a sea urchin fertility test and a microbial test to

evaluate chronic toxicity in selected estuaries, NOAA found that

43 to 62 percent of the sediment samples from these selected

estuaries showed chronic toxicity.

Indicator Gaps and Limitations

Sediment toxicity tests are a useful tool to establish the potential

availability of contaminants in sediments. That availability can,

however, be affected by artifacts of laboratory procedures that

may make contaminants more or less available. Also, natural sediment features such as particle size and the presence of ammonia

and sulfides may cause toxicity that is not related to the presence

of contaminants.

Data Sources

Data for this indicator came from EPA’s Environmental Monitoring

and Assessment Program, Estuaries Program to Estuaries Dataset,

and the National Oceanic and Atmospheric Administration’s

Status and Trends Program. (See Appendix B, page B-16, for more

information.)

Indicator Sediment toxicity in estuaries – Category 2 (continued)

Chapter 2 - Purer Water 2.2 Waters and Watersheds 2-49

2.2.5 What ecological effects are

associated with impaired waters?

No single program examines the ecological condition of our nation’s

surface waters. However, a number of regional programs do track the

biotic condition of aquatic organisms and attempt to relate degradations in their condition to observed pressures on aquatic systems.

Biotic condition does not fully represent the breadth of ecological

parameters that ideally would be needed to answer the question,

“What are the ecological effects of impaired waters?” However, biological condition is widely acknowledged as a valuable indicator that

contributes to an understanding of overall ecological condition.

There are several measures of biotic condition; three were selected

for this report:

Q Fish index of biotic integrity (IBI) in streams.

Q Macroinvertebrate IBI for streams.

Q Benthic community index (coastal waters).

These indicators are discussed in detail in Chapter 5, Ecological

Condition. As they are relevant to water quality, they are briefly summarized below to demonstrate their effectiveness for future national

assessments.

Fish and Macroinvertebrate Indices of Biotic Integrity

Consistent sampling methods and index development procedures were

used to measure the biotic integrity of fish and benthos in streams in

the Mid-Atlantic Highlands (EPA, ORD, Region 3, August 2000). The

mid-Atlantic streams were assessed using both fish and benthic insect

indicators. Of the stream miles assessed in the Mid-Atlantic Highlands,

the fish IBI indicated that 17 percent of the streams were in good condition and 31 percent were in poor condition. The macroinvertebrate

condition measures indicated that 17 percent of the Mid-Atlantic

Highland streams were in good condition, while 26 percent were in

poor condition. (See Chapter 5–Ecological Condition, for definitions

of these categories.)

The assessment permits estimates of both the number and proportion of stream miles in good, fair, or poor condition, but it does not

provide information about where these categories of streams are

located. Associations of biological condition with specific stressors

have not been completed. While the stressors found in the streams

can be identified, it is not possible to determine which stressors are

contributing to the observed biological condition.

Benthic Community Index (Coastal Waters)

Samples of bottom sediments were collected and benthic index

scores were assessed for the northeast, southeast, and Gulf coastal

areas. In these three areas, 56 percent of the coastal waters were

assessed in good condition, 22 percent in fair condition, and 

22 percent in poor condition. The work of associating biological

condition with specific stressors has been completed for these

coastal waters, so the stressors that co-occur with poor benthic

condition can be evaluated. Of the 22 percent of the coastal 

areas with poor benthic condition, 62 percent also had sediment

contamination, 11 percent had low dissolved oxygen concentration,

seven percent had low light penetration, and two percent showed

sediment toxicity (EPA, ORD, OW, September 2001).
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-50 2.3 Drinking Water Chapter 2 - Purer Water

2.3 Drinking Water

Drinking water comes from surface water and ground water. Largescale water supply systems tend to rely on surface water resources

(including rivers, lakes, and reservoirs), while smaller water systems

tend to use ground water. Slightly more than half of our nation’s

population receives its drinking water from ground water by means of

wells drilled into aquifers (USGS, 1998).

To protect human health, EPA, under the Safe Drinking Water Act

(SDWA), sets health-based standards (called maximum contaminant

levels, or MCLs) for contaminants in drinking water. These standards

specify the maximum allowable level of each regulated contaminant

in drinking water. The standards also prescribe protocols, frequencies, and locations that water suppliers must use to monitor for

about 90 regulated contaminants. The SDWA standards and associated monitoring and treatment by water suppliers provide a critical

barrier that serves to protect the quality of much of our nation’s

drinking water. Some 55,000 community water systems in the U.S.

test and treat water to remove contaminants before distributing it to

customers.

This section addresses three questions relevant to evaluating

progress in drinking water protection:

Q What is the quality of drinking water?

Q What are sources of drinking water contamination?

Q What human health effects are associated with drinking contaminated water?

An indicator has been developed to help answer the first of these

questions (Section 2.3.1). The second and third questions are

addressed in Sections 2.3.2 and 2.3.3, respectively; however, no

indicators were identified to answer these questions.

2.3.1 What is the quality of

drinking water?

In 2002, state data reported to EPA showed that approximately

251 million people were served by community water systems that

had no violations of health-based standards. This number represents 94 percent of the total population served by community

water systems, up from 79 percent in 1993. Under-reporting 

and late reporting of violations data by states to EPA affect the

accuracy of this data.

The drinking water standards set by EPA under the Safe Drinking

Water Act apply to public water systems (PWSs). PWSs are systems

that serve at least 25 people or 15 service connections for at least

60 days a year. They may be publicly or privately owned. PWSs

include:

Q Community water systems (CWSs)—systems that supply water to

the same population year- round. There are some 55,000 community water systems in the U.S.

Q Non-transient non-community water systems—systems that regularly

supply water to at least 25 of the same people at least 6 months

per year, but not year-round (e.g., schools, factories, office buildings, and hospitals that have their own water systems). 

Q Transient non-community water systems—systems that provide water

in a place where people do not remain for long periods of time

(e.g., a gas station or campground). 

Under the 1996 Amendments to the SDWA, EPA must go through

several steps to determine, first, whether setting a standard is appropriate for a particular contaminant, and if so, what the standard

should be. To make these determinations, EPA considers many factors for each contaminant, including: 

Q Its occurrence in the environment.

Q Human exposure and the risks of adverse health effects in the

general population and sensitive subpopulations.

Q Analytical methods of detection.

Q Available technology.

Q How the regulation would impact water systems and public health.

As of 2003, about 90 contaminants are regulated in drinking water

under the SDWA. 

Indicators

Population served by community water systems that meet all

health-based standards
Technical Document Q EPA’s Draft Report on the Environment 2003

Under SDWA regulations, all public water systems must monitor

the quality of their drinking water and report the monitoring

results to their state. Using these results, states determine

whether a maximum contaminant level has been violated and must

report all violations of federal drinking water regulations to EPA

quarterly. The indicator presents the total population across the

nation that is served by community water systems that met all

health-based drinking water standards. 

What the Data Show

In 2002, community water systems (CWS) served 268 million

people—just over 95 percent of the U.S. population as recorded

in the 2000 census. Analysis of state-reported violations data

shows that, in 2002, 94 percent of this population was served

by systems that met all drinking water standards (i.e., did not

report violations of health-based standards) for the entire year

(Exhibit 2-31).

Indicator Gaps and Limitations

Under-reporting and late reporting of CWS violations data by

states to EPA affect the ability to accurately report the quality of

our nation’s drinking water. EPA last quantified the quality of violations data in 1999. Based on this analysis, the agency estimated

that states were not reporting 40 percent of all health-based violations to EPA. EPA is continuing to verify state-reported CWS

data and expects to issue an updated estimate of data quality in

2003.

Data Source

The underlying database for this indicator is EPA’s Safe Drinking

Water Information System/Federal version. (See Appendix B, 

page B-16 for more information.)

Indicator Population served by community water systems that meet all health-based standards – Category 1

Chapter 2 - Purer Water 2.3 Drinking Water 2-51

Fiscal Year

Exhibit 2-31: Population served by community water 

systems (CWSs) with no reported 

violations of health-based standards, 

1993-2002

Population served by 

CWSs that had no 

reported violations

Percent of CWS-served 

population that was served 

by systems with no reported 

violations

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

250,596,287

239,927,650

239,299,701

229,805,285

224,808,251

215,351,842

213,109,672

208,700,100

202,626,433

196,229,162

94

91

91

91

89

87

86

84

83

79

Coverage: all 50 states

Source: EPA, Office of Water. Safe Drinking Water Information Systems/Federal version 

(SDWIS/FED). 2003.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-52 2.3 Drinking Water Chapter 2 - Purer Water

2.3.2 What are sources of 

drinking water contamination?

Microbiological, chemical, and radiological contaminants can enter

water supplies. These contaminants may be produced by human

activity or occur naturally. For instance, chemicals can migrate from

disposal sites or underground storage systems and contaminate

sources of drinking water. Animal wastes, pesticides, and fertilizers

may be carried to lakes and streams by rainfall runoff or snow melt.

Nitrates from fertilizers can also be carried by runoff and percolate

through soil to contaminate ground water. Arsenic and radon are

examples of naturally occurring contaminants that may be released

into ground water as it travels through rock and soil. 

Human wastes from sewage and septic systems or wastes from animal

feedlots and wildlife carrying microbial pathogens may get into

waters ultimately used for drinking. Coliform bacteria from human

and animal wastes may be found in drinking water if the water is not

properly treated or disinfected. These bacteria are used as indicators

that other harmful microbial pathogens, such as Giardia,

Cryptosporidium, and E. coli O157:H7, might be in the water.

Disinfection of drinking water is a critical public health measure as it

provides a barrier against harmful microbes. Under the SDWA, all

surface water supplies, and ground water supplies with close hydrological connections to surface water must disinfect (and most must

also filter) their water to remove pathogens. However, disinfectants

such as chlorine react with naturally occurring organic matter in

source water and in distributions systems to form chemical by-products (known as disinfection by-products) such as trihalomethanes

and haloacetic acid compounds.

For systems that disinfect, water leaves the plant with a disinfectant

residual. However, in some cases water could become contaminated if

there is a breach in the distribution system.

2.3.3 What human health effects

are associated with drinking

contaminated water?

Effects of exposure to contaminants in drinking water will vary

depending on many factors, including the type of contaminant, its

concentration in drinking water, and how much contaminated water is

consumed over what period of time. 

Q Chemical contaminants. Chemical contaminants found or expected

to occur in drinking water can include metals, pesticides, and solvents. Most of these would be expected to cause no health effects

at the levels found in treated drinking water, but they may cause a

variety of biological responses at high doses. These could include

cosmetic effects (such as skin discoloration) or unpleasant odors,

as well as more severe health effects such as nervous system or

organ damage, developmental or reproductive effects, or cancer.

One well-studied consequence of drinking contaminated water is

the formation of methemoglobin in infants drinking formula with

more than 10 ppm nitrate. This altered hemoglobin does not carry

oxygen efficiently; too much of it in the blood of very young children can be fatal (i.e., blue baby syndrome).

Q Pathogens. The consequences of consuming water with pathogenic

microbes can include gastrointestinal illnesses causing stomach

pain, diarrhea, headache, vomiting, and fever. Waterborne

pathogens can cause diseases that are less common in the U.S.,

such as typhoid fever and cholera, as well as more common waterborne diseases such as giardiasis or cryptosporidiosis. Pathogenic

microbes can enter water from human and animal wastes. One of

the largest outbreaks of disease from contaminated water

occurred in Milwaukee in l993, when an estimated 400,000 people became ill from exposure to Cryptosporidium, a single-celled

parasite that is found in the large intestines of a large number of

animals, including cattle and humans. That outbreak killed more

than 50 people, the vast majority of whom had seriously weakened immune systems (Hoxie, et al., 1997).

Drinking water disinfection is one of the great public health success

stories of the 20th century. It has been a critical factor in reducing

the incidence of waterborne diseases such as typhoid, cholera, 

and hepatitis, as well as gastrointestinal illness in the U.S. Though

drinking water disinfection is a critical public health measure, the

process does generate disinfection by-products, as mentioned 

earlier. These compounds have been associated with cancer, developmental, and reproductive risks, the extent of which is still uncertain

(see Chapter 4–Human Health).
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.4 Recreation in and on the Water 2-53

2.4 Recreation in and on

the Water

Our nation’s rivers, lakes, and oceans are used for recreation in many

different ways, including swimming, fishing, and boating.

Environmental programs implemented under the Clean Water Act

(CWA) have significantly improved the quality of many of our

nation’s waters since the early 1970s. These programs help to maintain the quality of waters that have been specifically designated for

recreational uses and ensure that they do not become degraded in

the future. Despite this progress, recreational waters are threatened

or affected by pollution at some times and in various locations. For

example:

Q During and following heavy rainfall, the sewer systems in some

cities may become overloaded, resulting in the temporary discharge of raw sewage, wastewater, and storm water into rivers and

coastal areas.

Q Lakes and ponds may be affected by non-point source pollution,

for example from septic tanks and agricultural sources, resulting in

chemical contamination and elevated levels of nutrients. 

Q Industries are issued permits under the Clean Water Act that allow

discharges of certain treated wastewaters to rivers and streams.

These discharges compromise our ability to also use those waters

for recreational purposes.

Perhaps the greatest human health concern associated with pollution

of recreational waters is the potential for exposure to human

pathogens. Many Americans risk illness from exposure to contaminated

recreational waters. Epidemiology studies in the U.S. and abroad have

consistently found an association between disease burden and contaminated waters. State and local officials monitor water quality at public beaches and close the beaches or issue advisories when monitoring

indicates that pathogens in water may have exceeded thresholds for

public safety. The fact that hundreds of beach advisories and closings

are issued every year at recreational rivers, lakes, and coastal waters

throughout the U.S. suggests that our recreational waters are significantly impacted by pollution. Three questions are posed with regard to

recreational waters:

Q What is the condition of waters supporting recreational use?

Q What are sources of recreational water pollution?

Q What human health effects are associated with recreation in contaminated waters?

An indicator has been developed to help answer the first of these

three questions, at least with regard to pathogens in recreational

waters. The second and third questions are addressed in Sections

2.4.2 and 2.4.3, respectively. No indicators were identified to

answer these two questions. Note that concerns associated with

consumption of fish and shellfish, including fish and shellfish caught

through recreational activities, are discussed in Section 2.5. 

2.4.1 What is the condition of

waters supporting recreational

use?

As described in Section 2.2.1, a number of programs collect information on the condition of waters at a national scale, including the

conditions that support recreational uses of waters. However, for a

variety of reasons described in Section 2.2.1, none of these programs (including the widespread CWA-mandated 305[b] state data

collection and reporting program) produce data with sufficient confidence and scientific credibility to serve as a national indicator for

water quality condition. Nevertheless, data from an entirely different

source (state and local monitoring of water quality at beaches) can

be used to help answer the question “What is the condition of surface waters that support recreational use?”—at least with respect to

pathogen contamination. 

When local and state officials monitor water quality at beaches, they

generally test for indicator organisms, such as coliforms. Not all of

these organisms are harmful themselves, but their presence generally

suggests that disease-causing microorganisms are also likely to be

present. When indicator organisms exceed certain thresholds, local

or state officials will close the beach to the public. The number of

days that beaches are closed or under advisory provides the basis

for an indicator for recreational water quality with respect to

pathogen contamination. This indicator reflects decisions made by

state and local governments about whether pathogen levels are

above their public health thresholds at beaches under their jurisdiction. Beach closure/advisory data predominantly represent coastal

and Great Lakes areas. Data on inland waterways generally are not

available or are not collected and reported. Thus, the question

“What is the condition of surface waters that support recreational

use?” can only be addressed for a portion of coastal and Great Lakes

beaches on a national level at this time. 

Indicators

Number of beach days that beaches are closed or under 

advisory
EPA’s Draft Report on the Environment 2003 Q Technical Document

Data on beach closures are collected by EPA under the Beaches

Environmental Assessment and Coastal Health (BEACH) Program.

This program is authorized by Section 104 of the Clean Water Act

and described in EPA’s Action Plan for Beaches and Recreational

Waters (EPA, ORD, OW, March 1999).

The BEACH program collects data for the National Health

Protection Survey of Beaches by sending a questionnaire to managers (usually in health or environmental quality departments in

states, counties, or cities) who are responsible for monitoring

swimming beaches on the coasts or estuaries of the Atlantic

Ocean, Pacific Ocean, and Gulf of Mexico, and the shoreline of

the Great Lakes. Information on some other inland fresh water

beaches has also been collected. Responses to these surveys are

voluntary and have increased substantially from 159 local, state,

and federal agencies reporting in 1997, to 237 agencies reporting

on 2,445 beaches in 2001. 

What the Data Show

Using the survey data, EPA compiles the number of days that

beaches are closed or under advisory and compares that to the

total number of “beach days”—i.e., days that the beaches would

normally be open to the public. In 2001, survey respondents

reported a total of approximately 320,000 beach days during the

swimming season for the 2,445 beaches for which data were collected. These beaches were closed or under advisory on almost

six percent (over 19,000) of those beach days.

Indicator Gaps and Limitations 

This indicator has a number of limitations:

Q Since reporting is voluntary, the data cannot be extrapolated to

accurately determine the suitability on a national level of surface waters to support recreation. 

Q The indicator applies primarily at this time to coastal and Great

Lakes beaches, as relatively few fresh water inland beaches are

surveyed. 

Q The causes of closures vary greatly among states; therefore,

linking beach closures to human health problems or stressors is

difficult.

Q Some reports are based upon infrequent monitoring. Infrequent

monitoring could miss events that would cause closures.

Q In interpreting the data, the assumption is made that the public

was at minimal risk of exposure to waterborne illness on days

the beach was open. However, this may not always be true.

Data Source

Data for this indicator came from EPA’s National Health

Protection Survey of Beaches. (See Appendix B, page B-17 for

more information.)

Indicator Number of beach days that beaches are closed or under advisory – Category 2

2-54 2.4 Recreation in and on the Water Chapter 2 - Purer Water

2.4.2 What are sources of

recreational water pollution?

As mentioned earlier, beach advisories and closings in the U. S. are

generally due to elevated levels of indicator organisms, such as 

coliforms, some of which do not themselves cause disease but may

indicate the presence of disease-causing microorganisms. In the 

survey of beaches (see Section 2.4.1), respondents are asked to

identify, based on best professional judgment, the sources of pollution (i.e., the indicator organisms and any associated pathogens)

that caused a beach advisory or closing. Exhibit 2-32 presents the

sources reported for the 2001 swimming season.

For just over half the cases, the sources were unknown. Storm water

runoff was the reported cause for one-fifth (20 percent) of the

beach closing or advisories. Rainfall, particularly heavy rain, creates

runoff from farmland, city streets, construction sites, suburban lawns,

roofs and driveways. This runoff contains harmful contaminants,

including human and animal wastes, sediments, and excess nutrients.

Runoff can enter waterbodies directly or via the storm water

drainage system. Other reported causes of beach closings and advisories were: wildlife (10 percent), sewage line blockages and breaks

(four percent), improperly functioning onsite wastewater facilities

(i.e., septic systems—see Chapter 3–Better Protected Land) (three

percent), combined sewer overflows (three percent), sanitary sewer

overflows (two percent), boat discharges (two percent), and publicly

owned treatment works (one percent). No indicators have been

identified to answer the question “What are the sources of recreational water pollution?” at this time. 

2.4.3 What human health effects

are associated with recreation in

contaminated waters?

The primary health concern associated with recreational waters is

the risk of infection from waterborne pathogens. People may be at
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.4 Recreation in and on the Water 2-55

risk if they ingest or inhale contaminated water, or simply through

general dermal contact with the water. Some people may be more

vulnerable than others, either because they are more susceptible to

infection or because they have greater exposure to the water. For

example, children may be more vulnerable to environmental exposure

due to their active behavior and developing immune systems. Elderly

and immunosuppressed persons may also be more vulnerable. 

The health effects of swimming in contaminated waters are usually

minor—sore throats, ear infections, and diarrhea. In some instances,

however, effects can be more serious and even fatal. Waterborne

microbes can cause meningitis, encephalitis, and severe gastroenteritis (EPA, ORD, OW, March 1999). However, data on the effects and

number of occurrences are limited. The number of occurrences are

likely under-reported because individuals may not link common

symptoms (e.g., gastrointestinal ailments, sore throats) to exposure

to contaminated recreational waters. At this time, no indicators have

been identified to quantify the health effects associated with recreation in contaminated waters. Additional research is needed to better

understand the types and extent of health effects associated with

swimming in contaminated water. CSO - Combined Sewer Overflow

SSO - Sanitary Sewer Overflow

POTW - Publicly Owned Treatment Works

Exhibit 2-32: Reported sources of pollution that 

resulted in beach closings or advisories, 2001

Sewage line blockage/break 4%

Septic system 3% POTW 1%

SSO 2%

Boat discharge 2%

CSO 3%

Wildlife

10%

Stormwater

runoff

20%

Other

3%

Unknown

52%

Source: EPA, Office of Water. EPA's BEACH Watch Program: 2001 Swimming Season. 

May 2002.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-56 2.5 Consumption of Fish and Shellfish Chapter 2 - Purer Water

2.5 Consumption of Fish

and Shellfish

Many coastal and fresh water environments are contaminated with

a variety of toxic substances. Of particular concern are mercury,

DDT, and PCBs because they persist in the environment and

bioaccumulate in the food chain. Though PCBs and DDT are no

longer manufactured or distributed in the U.S., they persist in historical deposits in watersheds and near-shore sediments. These

deposits continue to provide an active source for contaminating

fish and shellfish. Mercury can come from several sources, including

industrial releases, abandoned mines, the burning of fossil fuels for

electric power generation, and natural sources such as weathering

of rock and volcanoes.

Persistent chemicals enter the food chain when they are ingested

by bottom-dwelling (benthic) organisms. Benthic organisms are

eaten by smaller fish, which in turn are eaten by larger fish, which

may be consumed by humans or wildlife. Levels of PCBs and DDTs

are a concern in bottom-feeding fish and shellfish, as well as in

higher-level predators. Mercury is concentrated particularly in 

larger and longer-lived predators, such as large-mouth bass, tunas,

swordfish, and some sharks. Concentrations of all these compounds, especially in larger fish, can reach levels that are harmful

to humans. To protect human health, state and local officials 

monitor levels of these compounds in fish and shellfish, and issue

advisories when tissue concentrations exceed threshold levels.

Typically, a fish or shellfish advisory will suggest that intake of a

particular species be limited, especially for those at higher risk of

health effects such as children, pregnant women, and nursing

mothers. 

Three questions have been posed concerning consumption of fish

and shellfish: 

Q What is the condition of waters that support consumption of fish

and shellfish?

Q What are contaminants in fish and shellfish, and where do they

originate?

Q What human health effects are associated with consuming contaminated fish and shellfish?

Sections 2.5.1, 2.5.2, and 2.5.3, respectively, discuss these questions and, where available, the indicators that are used to help

answer these questions. 

2.5.1 What is the condition of

waters that support consumption

of fish and shellfish?

Three indicators, presented on the following pages, are available to

help answer this question: 

Q Percentage of river miles and lake acres with fish consumption

advisories.

Q Contaminants in fresh water fish.

Q Number of watersheds exceeding health-based national water

quality criteria for mercury and PCBs in fish tissue.

The first indicator describes the extent of fish advisories, such as

closed fisheries and/or restricted fish consumption. Fish advisories

are issued by state or local authorities when levels of contaminants

in monitored fish exceed threshold levels. These advisories, which are

widespread across the U.S., limit or restrict consumption of contaminated species. Mercury, dioxin, PCBs, DDT, and chlordane are

responsible for many of these advisories (EPA, OW, May 2002a).

Increases in the number of advisories over the years may reflect

increased monitoring, increased contamination, and in some cases,

more stringent health standards.

The second indicator examines the number of contaminants in fish

tissue from samples across the nation. This indicator shows that

more than 90 percent of sampled fish had at least one contaminant

and more than half had at least five. 

The third indicator compares average fish tissue concentrations of

mercury and PCBs across watersheds to human-health based water

quality criteria. This analysis showed that more than 30 percent of

the watersheds for which there are data exceed mercury criteria.

These watersheds are predominantly located in eastern coastal

states, New England, and the lower portion of the Mississippi River

watershed. 

For all three indicators, data are based on fish tissue data collected

by state or local government agencies, which tend to focus primarily

on areas where these agencies believe there may be contaminated

fish. This bias may result in inaccurate estimates of the extent of

contamination.

Indicators

Percentage of river miles and lake acres with fish consumption

advisories

Contaminants in fresh water fish

Number of watersheds exceeding health-based national water

quality criteria for mercury and PCBs in fish tissue
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.5 Consumption of Fish and Shellfish 2-57

Coastal Fish

For coastal fish, insufficient data on the edible portion of these fish

are available to provide a national indicator. However, examination of

fish tissue collected in coastal waters of the eastern U.S. and Gulf of

Mexico shows that compounds of concern were present at levels

above EPA’s threshold for issuing an advisory. 

Shellfish

No national indicators are available for shellfish. However, as discussed

below, data are available on the extent of shellfish waters that were

classified as harvest-limited or harvest-prohibited from 1966 to 1995.

These data show a steady decrease over this time period in the extent

of waters classified as harvest-limited or harvest-prohibited. Still, as 

of 1995, harvesting was limited in 31 percent of shellfish waters and

prohibited in 13 percent (NOAA, 1997). The predominant causes of

closures are both human and non-human coliform bacteria.

Data on shellfish waters come from the National Oceanic and

Atmospheric Administration (NOAA), which records areas that are

closed to shellfishing or are subjected to restricted or conditional

harvesting. NOAA obtains its data from coastal states, which identify,

survey, and classify shellfish-growing waters according to National

Sanitary Survey Program (NSSP) guidelines (FDA, 1993).

Classification status is based on sanitary surveys of water quality and

shoreline surveys of pollution sources. Individual shellfish-growing

areas are classified either as approved for harvest or as one of four

harvest-limited categories: conditionally approved, restricted, conditionally restricted, and prohibited. 

All identified shellfish-growing waters must be classified as prohibited

unless sanitary surveys indicate that water quality meets specific

NSSP standards for the other categories. Harvesting is permissible in

approved areas year-round. The conditionally approved and conditionally restricted categories are for voluntary use by states when a

predictable pollution event such as seasonal population, heavy rainfall, or fluctuating discharges from local sewage plants affects the

suitability of an area for harvest. Most shellfish harvest restrictions

are made based on the concentration of fecal coliform bacteria in

shellfish. This organism is not directly harmful to humans, but typically is associated with human sewage and with organic wastes from

livestock and wildlife. 

The National Shellfish Register provides a record of the acreage of all

classified shellfish-growing waters in the conterminous U.S. The

Register was first published in 1966 to meet the need for summary

information on the status and extent of the nation’s commercial

shellfish-growing areas. Since the publication of the first Register, the

acreage of classified shellfish-growing waters has increased more

than two-fold from 10 million acres to more than 21 million acres

(Houser and Silva, 1966; FDA, 1971; EPA, OE, 1975; DOC and HHS,

1985; NOAA, 1991; NOAA,1997), primarily due to an expanding

consumer demand for shellfish. 

Since 1966, the percentage of all classified waters approved for harvest has decreased 10 percent. However, data compiled for the 1995

Register, the last available compilation, suggest significant improvements. For example, the overall percent of harvest-limited waters

decreased from a high of 42 percent in 1985 to 31 percent in 1995.

The percent of prohibited waters also decreased from a high of 26

percent in 1974 to 13 percent in 1995—the lowest percentage

recorded. 
EPA’s Draft Report on the Environment 2003 Q Technical Document

State and local governments protect people from possible risks of

eating contaminated fish by monitoring local waters and issuing

fish advisories when contaminant levels are unsafe. A consumption

advisory may recommend that people limit or avoid eating certain

species of fish caught from certain lakes, rivers, or coastal waters.

Advisories are often very specific. They may apply to specific

water types (such as lakes), or they might include recommendations for specific groups (such as pregnant women or children).

Advisories apply to locally caught fish or wildlife as well as fish

purchased in stores and restaurants. EPA has compiled these advisory data into the National Listing of Fish and Wildlife Advisories

(NLFWA) database, which lists, among other things, the species

and size of fish or wildlife under advisory, the chemical contaminants covered by the advisory, the location and surface area of

the waterbody under advisory, and the population subject to the

advisory.

What the Data Show

Exhibit 2-33 shows the percent of the nation’s river miles and lake

acres under advisory for the years 1993 to 2001. Note that the

Great Lakes and their connecting waters are considered separately

from other waters and are not included in the calculations of total

lake acres or river miles. Except for 1998, the percentage

increased continuously during this 8-year period. Approximately

79,119 lakes (11,277,276 lake acres) and 485,205 river miles were

under advisory in 2001, compared to 14,962 lakes and 74,505

river miles under advisory in 1993. Note that the increase in the

total size of waters under advisory is due in part to increased

monitoring for chemical contaminants in fish and wildlife tissue

and the states’ increasing use of statewide advisories. Currently,

the 2,618 advisories in the national listing represent almost 

28 percent of the nation’s total lake acreage and 14 percent of

the nation’s total river miles. 

In addition to the NLFWA data, much information is available on

the advisory status of our nation’s waters. EPA and FDA issued a

national mercury advisory in January 2001 recommending that

women of childbearing age and young children limit their consumption of fish (<http://www.epa.gov/waterscience/fish>).

Many great waters of the U.S. are currently under fish advisories

for a variety of pollutants. The great waters include the Great

Lakes, Lake Champlain, the Chesapeake Bay, 20 National Estuary

Program (NEP) sites, and 14 National Estuarine Research Reserve

System (NERRS) sites. 

Q All of the Great Lakes and their connecting waters are under

advisory. 

Q Lake Champlain is under advisory for PCBs and mercury.

Q Although the Chesapeake Bay is not under any advisories, the

Potomac, James, Back, and Anacostia Rivers, which connect to

it, are all under PCB advisories. 

Q Baltimore Harbor, which also connects to the Chesapeake Bay,

is under advisory for chlordane and PCB contamination in fish

and blue crabs. 

Q Many of the major estuaries listed in the NEP and/or designated

as NERRS sites are under fish and/or shellfish advisories for multiple chemical contaminants. Sixty-five percent of the total number

of NEP, NERRS, and combined sites are under fish consumption

advisories. Seventeen sites have no current fish consumption

advisories. 

Several states have issued fish advisories for all of their coastal

waters. An estimated 71 percent of the coastline of the 

conterminous 48 states currently is under advisory. This includes

92 percent of the Atlantic coast and 100 percent of the gulf

coast. The Atlantic coastal advisories have been issued for a wide

variety of chemical contaminants, including mercury, PCBs, dioxins,

and cadmium. All of the gulf coast advisories have been issued for

mercury, although other contaminants may also be present. No

Pacific coast state has issued a statewide advisory for any of its

coastal waters, although several local areas along the Pacific coast

are under advisory.

Indicator Gaps and Limitations

Currently, fish consumption advisories are being used as a way of

informing the public of risks associated with eating contaminated

Indicator Percent of river miles and lake acres under fish consumption advisories – Category 2

2-58 2.5 Consumption of Fish and Shellfish Chapter 2 - Purer Water Percent of total acres or miles under advisory 

30

25

20

15

10

5

0

1993 1994 1995 1996 1997 1998 1999 2000 2001

Exhibit 2-33: Trends in percentage of river miles and 

lake acres under fish consumption advisory, 

1993–2001

River Miles

Lake Acres

Coverage: all 50 states

Source: EPA, Office of Water. Update: National Listing of Fish and Wildlife 

Advisories. May 2002.
Technical Document Q EPA’s Draft Report on the Environment 2003

fish in certain waterbodies. Advisories are based on fish tissue

monitoring data collected by states and are largely focused on

areas where states know fishing occurs or suspect contamination.

Criteria used to issue advisories vary among states, with some

having more stringent criteria and more robust advisory programs

than others. 

Due to the large range in geographic size of lake acres and river

miles affected by chemical contaminants that may be contained

under a single advisory, the number of advisories is not as accurate a measure of the contamination as geographic extent. As a

result, information is now provided on total lake acres and river

miles where advisories are currently in effect. A large-scale fish

tissue study is underway and will help identify waters that

require further monitoring to determine whether advisories are

necessary.

This indicator is based on fish tissue monitoring data collected

by the states. It does not provide unbiased geographical coverage, and it is largely focused on areas where states know fishing

occurs or suspect contamination problems. At present, 43

states issued risk-based advisories.

Data Source

Fish advisory indicator data are from the National Listing of Fish

and Wildlife Advisories program. (See Appendix B, page B-17, for

more information.)

Indicator Percent of river miles and lake acres under fish consumption advisories – Category 2 (continued)

Chapter 2 - Purer Water 2.5 Consumption of Fish and Shellfish 2-59

From 1992 to 1998, fish samples were collected from 223 stream

sites in the U.S. Geological Survey’s (USGS) National Water

Quality Assessment (NAWQA) program. Tissue composites from

whole fish were analyzed for PCBs, organochlorine pesticides, and

trace elements. These contaminants may harm organisms directly

or by affecting their reproduction, and they may make fish unsuitable for consumption by humans. These data were compiled for

the entire U.S. 

What the Data Show

More than 90 percent of sampled fish had at least one contaminant detected and about half of the fish tested had at least five

contaminants at detectable levels (Exhibit 2-34) (The Heinz

Center, 2002). All fish tested from the Great Lakes had five or

more detected contaminants.

Indicator Gaps and Limitations

The sites sampled are representative of a wide range of stream

sizes, types, and land uses broadly distributed across the U.S., but

they do not represent a probability sample, so confidence bounds

on the estimates could not be calculated (Gilliom, et al., 2002;

The Heinz Center, 2002).

Fish tissue concentration data are derived from composites of

whole fish and not from edible portions alone. Thus it is not possible to compare tissue concentrations to aquatic or human health

Indicator Contaminants in fresh water fish – Category 2

Exhibit 2-34: Occurrence of contaminants in stream 

fish, 1992-1998

100

80

60

40

20

0

1992 to 1998

Percent of Stream Sites with Indicated 

Number of Contaminants Detected

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the 

U.S. Geological Survey.

Coverage: lower 48 states.

Note: Partial indicator data: freshwater stream fish only, 

1 or 2

3 or 4

5 or more
EPA’s Draft Report on the Environment 2003 Q Technical Document

guidelines. These data do, however, indicate organism exposure to

measured chemicals. 

Data Source

Data for this indicator came from the U.S. Geological Survey’s

National Water Quality Assessment Program as compiled for The

Heinz Center (2002). (See Appendix B, page B-17, for more

information.)

Indicator Contaminants in fresh water fish – Category 2 (continued)

2-60 2.5 Consumption of Fish and Shellfish Chapter 2 - Purer Water

For this indicator, fish tissue concentrations of each chemical in

the NLFWA database were averaged across 8-digit hydrologic unit

code (HUC) watersheds. The average concentration was then

compared to fish- tissue based criteria for mercury and PCBs. The

average fish tissue concentration is for all monitored species, fillet

samples only (whole fish samples were omitted from the analysis

as these are not recommended for use in assessing human health

impact). Thus, the average is meant to represent the potential

exposure concentration for persons consuming fish from typically

frequented local lakes, streams, and rivers. 

The mercury criterion used in this comparison was the national

fish-tissue-based criterion. The PCBs criterion was based on the

fish tissue levels used to derive the current national health-based

water concentration criteria. Criteria

exceedances can be interpreted as

meaning that the watershed, on average, is not meeting maximum tissue

contaminant levels designed to be

protective of human health.

What the Data Show

The data for mercury are a fairly

good representation of conditions in

the eastern U.S. and California. Of

the 696 8-digit HUC watersheds with

available data, 225 exceeded the mercury criterion (Exhibit 2-35). These

are predominantly located in eastern

coastal states, New England, and the

lower portion of the Mississippi River

watershed. Data for PCB concentrations are less available; 114 of 153

watersheds where data were available

contained tissue above the criterion

level (Exhibit 2-36).

Indicator Number of watersheds exceeding health-based national water quality criteria for mercury and PCBs 

in fish tissue – Category 2

Exhibit 2-35: Watersheds with fish tissue concentrations exceeding health-based national water quality 

criteria for mercury, 2001

% Reduction to Meet Criterion

Currently Meets Criterion

10% Reduction Required

15% Reduction Required

20% Reduction Required

25% Reduction Required

50% Reduction Required

75% Reduction Required

>75% Reduction Required

Contains Other Sources

No Georeferenced Fish Data

States currently use water column concentration-based mercury water 

quality standards and would need to adopt fish tissue-based target 

levels in order to use this approach for mercury Total Maximum Daily 

Loads. Additional reductions would be required to meet EPA national 

and most state fish advisory levels, which are often set below the 

methyl-mercury criterion.

Note: Watersheds highlighted yellow have "significant" mercury sources other than deposition, 

defined as where the total estimated load from Publicly Owned Treatment Works (POTWs) and pulp 

and paper mills is greater than 5% of estimated waterbody delivered mercury at a typical air 

deposition load (10 g/km2/yr) and/or where mercury cell chlor-alkali facilities, mercury mines, or 

significant past producer gold mines are present

Source: EPA, Office of Water. National Listing of Fish and Wildlife Advisories (NLFWA) Mercury Fish Tissue Database. June 2001.

Coverage does not include Alaska, Hawaii, or Puerto Rico
Technical Document Q EPA’s Draft Report on the Environment 2003

Indicator Gaps and Limitations

Several limitations should be noted for this indicator: 

Q The data were compiled based on voluntary contributions

from individual states and have not undergone an independent quality assurance/quality control (QA/QC) review. Data

quality is a function of the distinct programs for which the

data were collected.

Q Sampling by state agencies was not generally done on a 

statistical basis, but rather was targeted toward specific waterbodies and fish species. Some selection of sampling locations

was based on fishing pressure and/or suspected elevated contaminant levels. For example, there appears to be a bias in the

mercury data towards top predator or sport fish (of the top 10

most frequent species sampled, 83 percent are trophic level 4

species). This bias could potentially skew the average watershed

concentration level to higher than actual exposure depending on

real consumption patterns.

Q Some states may not have reported tissue data when resultant

concentrations were found to be below state fish advisory levels.

Q Substantially more data are available for the years 1990 to

1995 than for more recent years. 

Q Spatial gaps in the data are readily apparent from the indicator

maps. Since a large fraction (roughly two-thirds) of the database was not georeferenced (i.e., no latitude/longitude coordinates were created), those data

could not included in the indicator. Bias imposed by these missing data was not examined.

Latitude/longitude coordinates

will be assigned in a database

update in the near future and

can be incorporated in future

indicators.

Q The human health-based criteria

of 0.3 ppm methylmercury that

was used for comparison is 

considerably higher than the

more recent federal advisory of

0.18 ppm for consumption of

mercury-contaminated fish. State

consumption advisories are 

typically at levels closer to the

0.18 ppm than to the 0.3 ppm

level. 

Q Sampling patterns of state agencies are largely being directed

toward areas of higher fishing

pressure or based on suspected

elevated contaminant levels. Thus this indicator, which is based

on generalizing from specific sampling locations to watershed

averages, is expected to represent a somewhat conservative

estimate of the average concentration in consumed fish in each

respective area.

Data Sources

The fish tissue indicator data are from the National Listing of Fish

and Wildlife Advisories program. (See Appendix B, page B-18, for

more information.)

Indicator Number of watersheds exceeding health-based national water quality criteria for mercury and PCBs 

in fish tissue – Category 2 (continued)

Chapter 2 - Purer Water 2.5 Consumption of Fish and Shellfish 2-61

Exhibit 2-36: Watersheds with fish tissue concentrations exceeding health-based national water quality 

criteria for polychlorinated biphenyls (PCBs), 2001

All Results are Non-Detect

Currently Meets EPA Criterion

>1000% Above Criterion

100% to 1000% Above Criterion

<100% Above Criterion

No Georeferenced Fish Tissue Data

Half for Less Than Detection

Note: Graphic was created for this report in ArcView using NLFWA data.

Source: EPA, Office of Water. National Listing of Fish and Wildlife Advisories (NLFWA). June 2001.

Coverage does not include Alaska, Hawaii, or Puerto Rico.
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-62 2.5 Consumption of Fish and Shellfish Chapter 2 - Purer Water

2.5.2 What are contaminants in

fish and shellfish, and where do

they originate?

Information is available to help answer this question in a general

sense. Fish and shellfish can be contaminated by both chemical pollutants and pathogens. Chemical contaminants of greatest concern

tend to be those that are toxic and persistent and that bioaccumulate. Contaminants with these properties that are common in fresh

and coastal waters include:

Q DDT and PCBs. The manufacture and use of these compounds

have been banned in the U.S. However, deposits from past pollution persist in sediments and land-based sources, and these

deposits continue to pollute watersheds. In addition, PCBs can be

found in some products manufactured prior to the ban (e.g., electrical transformers).

Q Mercury. This metal, a natural and highly toxic element, can now be

detected (although in small amounts) in all waters. Sources of

mercury include wastes from past mining practices and the burning

of fossil fuels and wastes, which can create mercury emissions that

settle on land and water. In water, bacteria convert mercury to

methylmercury, a toxic compound that is absorbed by fish and

accumulates in their tissue. 

Biological threats to shellfish consumption include bacterial contamination from human and animal wastes and contamination from

naturally occurring toxins that shellfish accumulate from consuming

certain algae.

Some data are available on the sources of bacterial contamination.

When state managers close or otherwise restrict a shellfish-growing

area due to high levels of fecal coliform bacteria, they typically cite

potential sources of that contamination. This information was collected for the 1990 and 1995 Shellfish Registers (NOAA, 1991;

NOAA, 1997). In 1995, sources of shellfish contamination cited by

reporting officials were (in decreasing order of frequency): 

Q Urban runoff (40 percent)

Q Unidentified sources upstream of coastal watersheds (39 percent)

Q Wildlife (38 percent)

Q Individual wastewater treatment systems (e.g., septic tanks) (32

percent)

Q Wastewater treatment plants (24 percent)

Q Agricultural runoff (17 percent)

Q Marinas (17 percent)

Q Boating (13 percent)

Q Industrial facilities (9 percent)

Q Combined sewer overflows (7 percent)

Q Direct discharges (4 percent)

Q Feedlots (3 percent)

The 1990 Register reflects the same top five sources of pollution,

although in slightly different order. 

Marine biotoxins associated with “red tides” and other naturally

occurring contaminants such as Vibrio species (a free-living marine

and estuarine bacteria associated with stomach and intestinal disorders of varying intensity) can also cause temporary closures,

although they are not usually regarded as a pollution source (Rippey,

1994; FDA, 1993). 

At this time, insufficient data are available to develop national-level

indicators about the type and origin of fish and shellfish contaminants.

2.5.3 What human health effects

are associated with consuming

contaminated fish and shellfish?

The health effects of consuming contaminated fish and shellfish

depend on many factors, including the type of contaminant, its concentration in the organism, and how much contaminated fish or shellfish is consumed. Health effects include the following:

Q Risk assessments show that exposure to sufficient levels of some

contaminants in fish tissues may increase the risk of cancer

Q Mercury, in sufficient quantities, is toxic—especially to the 

nervous system. 

Q Shellfish contaminated with fecal wastes can cause gastrointestinal

illness and even death in individuals with compromised immune

systems. Mollusks, mussels and whelks are the main shellfish that

carry biotoxins causing common symptoms, such as irritation of

the eyes, nose, throat, and tingling of the lips and tongue. 

Advisories warn the public of these risks and suggest limits or outright bans on consuming some species in certain problem areas.

Certain groups may be at higher risk for health effects from contaminated fish and shellfish. These include children, pregnant women, and

nursing mothers, who may be more vulnerable to effects, and tribal,

ethnic, and other populations that fish for subsistence and therefore

consume more fish or shellfish. 

At this time, insufficient data are available to develop indicators that

can monitor, at the national level, the health effects of consuming

contaminated fish and shellfish. Chapter 4, Human Health, provides

more information on the human health impacts of contaminated fish.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 2 - Purer Water 2.6 Challenges and Data Gaps 2-63

2.6 Challenges and Data

Gaps 

Tremendous amounts of data are being collected on water resources.

These data provide evidence of water quality condition at the

national, regional, and state scales. Some of these data are

sufficiently comprehensive in scope to serve as the basis for

indicators of water quality at the national level. These indicators

provide a starting point for describing our nation’s water quality.

However, as discussed below, they also have limitations that make it

difficult to make confident statements about the condition of water

resources at the national scale or to thoroughly describe the

stressors that degrade that condition. 

2.6.1 Waters and Watersheds

Several indicators are available that provide information about the

quality of our nation’s waters and watersheds. For wetlands, for example, the relevant indicator shows that the rate of wetland loss has

dropped dramatically in recent years. However, as discussed in

Section 2.2.2, there currently are no indicators of wetland biological

condition and none are being implemented at the national or regional

scale. Without these indicators and an assessment process, ensuring

that the net gain goal is sustaining not only wetland extent, but also

wetland condition, will not be possible.

Drawing accurate conclusions about the condition of surface waters

can be equally as challenging as for wetlands, but the indicators in

this area do provide evidence of some success in reducing important

stressors. In addition, data suggest that atmospheric deposition of

sulfates has been reduced (EPA, ORD, January 2003), which will help

improve the quality of acidic surface waters. Ongoing efforts by EPA

(for example, through the National Pollutant Discharge Elimination

System permit program), the U.S. Department of Agriculture, and

individual states to reduce the amount of pollutants discharged to

our nation’s waters from both point and non- point sources will also

help to improve water quality.

However, many challenges remain in monitoring water quality and

taking steps to improve water quality. This is, in part, because significant environmental problems persist, despite environmental management activities to address these problems. Persistent hypoxia in the

Gulf of Mexico and fish contaminated by toxic organics and mercury

are examples. 

To better address water quality problems in the future, more and

better quality data on the condition of waters and watersheds will

be needed. This will require a greater collaboration among the 

federal agencies that participate in monitoring and managing our

nation’s waters so that results and metadata can be provided in a

common format. Data in a common format will be much more useful

for developing or improving indicators and can also more easily be

made available to the public. In addition, the relevant federal agencies should work with the states to design and implement cost-efficient water quality monitoring programs whose data will be useful

not only to the state water quality programs, but also to national

water quality characterizations. State resources often are limited for

such key activities as characterizing waters, identifying sources of

watershed stress, and monitoring the effects of implementing pollution controls. Therefore, it is critical to encourage the development,

dissemination, and use of cost-effective monitoring and assessment

tools, such as biological methods for water quality assessment and

a new framework for design and data collection in water quality

monitoring programs.

2.6.2 Drinking Water 

The indicator for the quality of treated drinking water in the U.S.

shows that quality of drinking water has improved from the early

1990s through 2002. This indicator is based on health standards

violations by community water systems that are reported by states

to EPA’s Safe Drinking Water Information System (SDWIS). The 

systems that are monitored under SDWIS serve water to about 

95 percent of the U.S. population. Compliance trends may change

in the future as new regulations create new compliance challenges

for public water systems.

The primary limitation of this indicator is under-reporting and late

reporting of community water systems violations by states to EPA.

This affects the accuracy of annual reports produced using SDWIS

and thus the quality of the indicator. EPA last quantified data 

quality in 1999 and estimated that states were not reporting 

40 percent of all health-based violations. EPA and states are taking

steps to address identified deficiencies and to improve data quality.

A survey of reporting completeness is underway. Another limitation

of the indicator is that it does not cover the quality of water from

private wells.

It is important to understand the condition of the raw waters 

(both ground water and surface waters) that serve as drinking 

water sources. For example:

Q States are currently conducting assessments to delineate the extent

of source waters and identify potential contaminant sources.

Q Data provided by the U.S. Geological Survey under its National

Water Quality Assessment program and occurrence data for unregulated contaminants collected by EPA under the Safe Drinking

Water Act (SDWA) also provide information about raw water stressors, and are used by EPA to determine whether additional contaminants should be regulated under the SDWA.

Q It is important that EPA assure that the frequency of sampling is

adequate to characterize episodic events affecting source water

quality. 
EPA’s Draft Report on the Environment 2003 Q Technical Document

2-64 2.6 Challenges and Data Gaps Chapter 2 - Purer Water

The incidence of waterborne disease is another parameter that

could be used to describe and track water quality at the national

level. Additional efforts to obtain data could help provide a basis

in the future for a national-level indicator in this area. This would,

however, require significant new work, as the existing data likely

reflect an unknown but probably very large degree of underreporting. For example, there currently are no consistent national

surveillance and reporting requirements for doctors or states with

respect to incidence of diarrhea, except as associated with

Hepatitis A, cholera, salmonellosis, or shigellosis. Doctors rarely

order the tests that would identify these diseases, or tests that

would identify other, more common diseases that can be caused by

contaminants in drinking water. 

2.6.3 Recreation in and on the Water

The quality of recreational waters is compromised when pollution

increases the level of pathogens or (to a lesser extent) chemical contaminants in those waters past thresholds judged safe for human

exposure. When this happens at a monitored beach, particularly for

pathogens, local or state authorities close or issues advisories for

beaches. Sufficient information is available to provide the basis for

an indicator about the risks to public health from exposure to

pathogens in recreational water at coastal and Great Lakes beaches.

Although the indicator shows that the number of beaches with advisories or closures has increased in recent years, this trend simply

represents the fact that more beaches are providing information. In

fact, as the indicator shows, the percent of beaches under advisory

or closure has been fairly constant over the last few years. Overall,

relatively few days (six percent of the days beaches could be open)

have been lost due to pathogen exposure. This indicator is limited by

three considerations: 

Q The number of beach days closed or under advisory does not

directly measure pathogens or contaminants in water.

Q Reporting of beach days closed or under advisory is voluntary,

thus the ability of this indicator to describe conditions nationwide

is unknown. 

Q At this time, this indicator applies primarily to coastal and Great

Lakes beaches, as most fresh water inland beaches are not

surveyed.

Q Improving the value of this indicator as a national measure of

recreational water quality would entail an assessment of the presence of pathogens in all waters used for recreational activities.

Chemical contaminants would need to be selectively measured in

waters with known risk from contamination. 

2.6.4 Consumption of Fish and Shellfish

Three indicators are available to help describe the condition of

surface waters that support fish and shellfish consumption. For

example, information about specific areas where contaminants in

fish are above public health thresholds is available. One indicator

suggests that the number of lake acres and river miles for which

fish consumption advisories have been issued is increasing. This

trend may represent an increase in monitoring, more stringent

state health standards, or increased contamination. Other indicators show that the vast majority of sampled fish are contaminated

to some degree and that contamination for particular pollutants

(mercury and PCBs) tends to be concentrated in certain areas of

the country. For all three indicators, it is important to note that

sampling tends to focus on areas where states know fishing occurs

or suspect there may be a contamination problem, so the data may

over-report or under-report the degree and extent of contamination. Also, monitoring of fish and shellfish at the state level is very

inconsistent, and different criteria are used to issue advisories.

A true national assessment of the safety of fish and shellfish 

for human consumption can only be accomplished through a 

comprehensive, representative survey of pathogens and chemical

contaminants in edible fish tissue in all waters. A national survey 

of this type, involving 500 lakes and reservoirs, is underway. Initial

data on 268 contaminants in the tissue of fresh water fish have

been collected. These data are not presented in this report

because they reflect only one year of a four-year study and, as

such, are not ready for public release. However, they should be

available for future use as a potential indicator.
Chapter 3:

Better Protected

Land
Indicators that were selected and included in this chapter were assigned to one of two categories:

■ Category 1 –The indicator has been peer reviewed and is supported by national level data coverage for more than one time period.

The supporting data are comparable across the nation and are characterized by sound collection methodologies, data management

systems, and quality assurance procedures.

■ Category 2 –The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multi-state

regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of the

indicator have been measured (e.g., data has been collected for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by sound collection methodologies, data management systems, and

quality assurance procedures.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.0 Introduction 3-3

3.0 Introduction

The U.S. landscape can be characterized in many different ways—by

its diversity and distribution of natural resources, by its complex pattern of land uses reflecting population distribution and management

strategies, and by the various ecological systems that provide habitat

for thousands of plant and animal species. This landscape is continuously changing due to population growth, the demand for resources

and energy, and changing land management practices. 

Our nation’s land provides the foundation on which cities are built

and from which food and other resources are derived to support the

population. At the same time, land used for these purposes can be

changed by pollution, waste disposal, and various physical processes

(e.g., land clearing) that can change natural processes, such as the

hydrologic cycle. Numerous laws and practices have been 

implemented—especially over the last 30 years—to help protect

human health and ecosystems from these types of human actions. 

This chapter addresses the types, extent, and uses of land in the

geographic area of the U.S., which comprises approximately 2.3 

billion acres of land and water (U.S. Census Bureau, 2001). This 

area includes all 50 states, as well as Puerto Rico, American Samoa,

Guam, the Northern Mariana Islands, Palau, and the U.S. Virgin

Islands. In total, 2.263 billion acres of the U.S. are land, while 116

million acres are water. This land acreage is the basis for all calculations of percentages in this chapter, unless otherwise noted.

Population growth is probably the single most important factor that

has changed and continues to change the land environment of the

U.S. The use of land is, to a major extent, a function of human needs

and population density. According to the 2000 Census, more than

281 million people live on our nation’s land. The U.S. has added at

least 20 million people per decade to its population over the last 50

years, and in the last decade (1990-2000), the U.S. population has

increased by more than 32 million (13 percent) (Exhibit 3-1). The

density of population has also continuously increased, although not

evenly across the country (Exhibit 3-2). According to the 2000

Census, the average density of people across our nation is approximately 0.125 people per acre. This represents a significant change

from the first census of population, conducted in 1790, showing

only 0.007 people per acre (U.S. Census Bureau, 2001). 

The exponential growth in the U.S. and world population has created

demands for resources and uses of land that have major effects on

both human health and ecological condition. The land indicators

outlined in this chapter are descriptors of the status, trends, and

effects of various conditions and land practices. These indicators are

often limited in their capacity to paint an accurate picture of the

effects of various human practices, due to incomplete, inconsistent,

or dated data.

The specific issues explored in this chapter include changing uses of

land for development, agriculture, and forest management; the use

and presence of chemicals in the form of pesticides, fertilizers, and

toxic releases; the generation and management of various types of

waste; and the extent of contaminated lands. The chapter poses 

fundamental questions about these issues and their health and 

ecological effects, and it uses indicators drawn from well-reviewed

data sources to help answer those questions. Exhibit 3-3 lists these

questions and indicators, and identifies the chapter section where

each indicator is presented.

The chapter is divided into four main sections:

■ Section 3.1 examines the extent of various ecological systems 

and land uses in the U.S.

■ Section 3.2 looks at the extent and potential disposition of 

chemicals used or managed on land.

■ Section 3.3 addresses waste generation and management on land

and the extent of contaminated lands.

■ Section 3.4 reviews the challenges and data gaps that remain in

assessing the condition of our nation’s land.

Each of the topic sections (e.g., land use, chemicals, waste) also 

considers what is currently known about associated human health

and ecological effects. 

Note: Large amounts of land area were added to the United States in the early 

1800s (Louisiana Purchase, 1803), mid-1800s (adding the present states of 

Oregon, Washington, Idaho, California, Nevada, Utah, and parts of Colorado, 

Kansas, Arizona, and New Mexico), and in 1959 (Alaska and Hawaii statehood). 

These land increases explain population density decreases during these periods.

Source: U.S. Census Bureau, Statistical Abstract of the United States 2001: The 

National Data Book. Washington DC: U.S. Census Bureau, 2001.

Exhibit 3-1: Population and population density, 1790-2000

Population in millions

0

50

100

150

200

250

300

1790 1810 1830 1850 1870 1890 1910 1930 1950 1970 1990

Population (millions)

Population Density (per acre mile)

Population per acre of land area

0.02

0

0.03

0.05

0.06

0.08

0.09

0.109

0.125
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-4 3.0 Introduction Chapter 3 - Better Protected Land

Numerous gaps in the data exist that make it difficult or impossible

to answer some of the questions posed about the condition of our

nation’s lands. The gaps and limitations of data are described briefly

under each question and in more detail at the end of the chapter.

There are several major sources of data that contribute to this 

chapter, and a report titled The State of the Nation’s Ecosystems,

developed by The H. John Heinz III Center for Science, Economics

and the Environment (The Heinz Center, 2002). These data sets

contribute directly and indirectly to many of the indicators 

throughout the chapter.

Exhibit 3-2: United States population density by county, 2000

0 100 Miles

0 100 Miles

0 100 Miles

0 100 Miles

U.S.

density

is 79.6

People per 

acre by county

>4.7

0.5 to 4.7

0.25 to 0.5

0.12 to 0.25

0.01 to 0.12

0.002 to 0.01

0 to 0.002

Source: Brewer, Cynthia A. and Trudy A. Suchan. Mapping Census 2000: The Geography of U.S. Diversity. June 2001.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.0 Introduction 3-5

Question Indicator Name Category Section

Question Indicator Name Category Section

Chemicals in the Landscape

1

2

1

2

2

1

2

3.1.1

3.1.1

3.1.2

3.1.2

3.1.3

3.1.4 

3.1.5

3.1.6

Land Use

Exhibit 3-3: Land – Questions and Indicators

How much and what types of toxic substances are released 

into the environment?

Agricultural pesticide use

Fertilizer use

Pesticide residues in food

Potential pesticide runoff from farm fields

Risk of nitrogen export

Risk of phosphorus export

No Category 1 or 2 indicator identified

No Category 1 or 2 indicator identified

2

2

2

1

1

2

2

3.2.1

3.2.2

3.2.3

3.2.4

3.2.4

3.2.4

3.2.4

3.2.5

3.2.6

What human health effects are associated with pesticides, 

fertilizers, and toxic substances?

What ecological effects are associated with pesticides, 

fertilizers, and toxic substances?

What is the extent of developed lands?

What is the extent of farmlands?

What is the extent of grasslands and shrublands?

What is the extent of forest lands?

What human health effects are associated with land use?

What ecological effects are associated with land use? 

What is the volume, distribution, and extent of pesticide use?

What is the volume, distribution, and extent of fertilizer use?

What is the potential disposition of chemicals from land?

Quantity and type of toxic chemicals released 

and managed

Extent of developed lands 

Extent of urban and suburban lands 

Extent of agricultural land uses 

The farmland landscape 

Extent of grasslands and shrublands

Extent of forest area, ownership, and management 

No Category 1 or 2 indicator identified 

Sediment runoff potential from croplands and pasturelands
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3-6 3.0 Introduction Chapter 3 - Better Protected Land

Question Indicator Name Category Section

2

2

2

2

2

2

2

3.3.1

3.3.1

3.3.1

3.3.2

3.3.2

3.3.3

3.3.3

3.3.4

3.3.5

Waste and Contaminated Lands

Quantity of municipal solid waste (MSW) generated and managed

Quantity of RCRA hazardous waste generated and managed

Quantity of radioactive waste generated and in inventory 

Number and location of municipal solid waste (MSW) landfills

Number and location of RCRA hazardous waste management facilities 

Number and location of Superfund National Priorities List (NPL) sites

Number and location of RCRA Corrective Action sites

What human health effects are associated with waste 

management and contaminated lands?

What ecological effects are associated with waste 

management and contaminated lands? 

What is the extent of land used for waste management?

What is the extent of contaminated lands?

How much and what types of waste are generated and

managed ? 

No Category 1 or 2 indicator identified 

No Category 1 or 2 indicator identified 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-7

3.1 Land Use 

Land ownership and the management objectives of the owners tend

to determine how land is used; thus, U.S. lands are used for many

different purposes. Nearly 28 percent of the nation (630 million

acres) is owned and managed by the federal government. State and

local governments manage another 198 million acres (GSA, 1999).

The more than 828 million acres of federal, state, and local 

government lands in the nation are managed for various public purposes. In contrast, the approximately 1.419 billion acres of private

and tribal land are more likely to be managed in the interests of

their owners, with various land use constraints imposed by zoning

and other regulations (GSA, 1999; USDA, NRCS, 1997; Alaska 

DNR, 2000). 

Management objectives are constantly changing on private and 

public lands and can have both positive and negative effects on the

natural environment and human health. Such effects include loss of

native habitat to agricultural practices; loss of prime agricultural

lands to urban/suburban development; changes in patterns of runoff

as a result of impervious surfaces, stream flow, dams, or irrigation

systems; habitat restoration based on land reclamation; and

urban/suburban development on previously contaminated land. 

There are differing estimates of the extent of various land uses. Those

discussed in the context of the following questions are often due to 

different classifications, definitions, approaches to data collection, and

the timing of data collection and analysis. Land cover and land use 

represent two different concepts and both are discussed in this section.

Land cover is essentially what can be seen on the land—the vegetation

or other physical characteristics—while land use describes how a piece

of land is being used (or not) by humans. In some cases, land uses can

be determined by cover types, which are visible (e.g., the presence of

housing indicates residential land use). Often, however, more information is needed for those uses that are not visible (e.g., lands leased for

mining, “reserved” forest land, shrublands with grazing rights).

Techniques for assessing land cover and land use vary, with different

data required to accurately assess extent and practices. Remotely

sensed data are increasingly being used to track land cover. When 

combined with knowledge of local land use regulations or other information, such data can be useful for tracking land use. 

Six questions are posed in this section to examine the extent of 

various ecological systems and land uses, including development,

agriculture, and forest management. The questions considered are:

■ What is the extent of developed lands?

■ What is the extent of farmlands?

■ What is the extent of grasslands and shrublands?

■ What is the extent of forest lands?

■ What human health effects are associated with land use?

■ What ecological effects are associated with land use?

Tracking national patterns of land use and activities that affect the

land can be challenging, primarily because land use is regulated by

many levels of government and also because of the significant variations in land cover, geography, and land activities nationwide. Data

produced by different agencies at different levels of government

must be integrated and analyzed continually to gain a national 

perspective of patterns and trends. 

The primary information sources for this section include the

National Resources Inventory (NRI) of the U.S. Department of

Agriculture (USDA) Natural Resources Conservation Service (NRCS);

the report titled The State of the Nation’s Ecosystems, which was

developed by The H. John Heinz III Center for Science, Economics

and the Environment (The Heinz Center, 2002); and data from the

Forest Inventory and Analysis (FIA) Program. 

This section presents various activities related to land use and land

cover. Two examples of activities for which indicators have not been

identified, but that can have significant effects in different ways on

land are 1) the formal protection or reservation of land for habitat

or natural resources and 2) mining and extraction activities. Some

data are collected locally and for federal lands (e.g., National Park

acreage) or tracked for economic indicators, but the national picture

of the extent of land reservation and mining is not generally available. A snapshot of what is known is described in the two sidebars.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-8 3.1 Land Use Chapter 3 - Better Protected Land

Land development is a process of land conversion that changes lands

from natural or agricultural uses to residential, industrial, transportation, or commercial uses to meet human needs. Land development

has created urban and suburban ecological systems, which are areas

where the majority of the land is devoted to or dominated by buildings, houses, roads, lawns, or other elements of human use and 

construction (The Heinz Center, 2002). Urban and suburban 

ecological systems are highly built up and paved, resulting in effects

such as more rapid changes in temperature, increased runoff, and

increased chemical contaminants than in more natural ecosystems.

Plant and animal life is more heavily influenced by species introduced

in horticulture and as pets, and native species may be more or less

completely removed from large areas and replaced by lawns, gardens,

and ornamentals (World Resources Institute, 2000).

The majority of Americans live in areas that are considered “developed land.” Between 1950 and 2000, the number of Americans 

living in U.S. Census Bureau-defined urban areas increased from 64

percent to 79 percent of the total population (U.S. Census Bureau,

2001). Estimates vary widely on the amount of land considered

developed in the U.S., depending on definitions of “developed” and

different assessment techniques. For example, the Census Bureau

definition is a measure of population density; not specifically a 

measure of actual land use or conversion of land. Census urban areas

do not take into account low-density suburbs and other developed

lands such as commercial or transportation infrastructure areas that

do not include people. The Census definitions may underestimate

lands that would be categorized as low-level residential or lands 

having dispersed development. (See the following sidebar for 

definitions used in this discussion.) 

3.1.1 What is the extent of

developed lands? 

MINING AND EXTRACTION ACTIVITIES

The U.S. is the world's largest producer and consumer of energy, and yet there is no inventory of lands used for energy production. There

are known to be 1,879 coal mines and associated facilities in the U.S (USGS, 2000a). The West, led by Wyoming, produces about half of

the U.S. coal, primarily from surface mines. The Appalachia area, led by West Virginia and Kentucky, accounts for 37 percent of U.S. coal

production, mainly from underground mines(DOE, November 2002). Other energy activities include 534,000 producing oil wells (ranging

from one to millions of barrels of production per year). Top producing areas of oil and natural gas include the Gulf of Mexico, Texas, Alaska,

California, Louisiana, Oklahoma, and Wyoming (DOE, November 2002). Eight uranium mines and 1,965 other mines and processing facilities produce most of the minerals and metals in the U.S (USGS, 2000b). About 5.4 billion metric tons of non-fuel mineral materials were

removed in 2000. Overall, 97 percent was mined and quarried at the surface level, and 3 percent was mined underground. The major states

in which mining for non-fuel minerals occurs are Nevada, Arizona, New Mexico, Minnesota, California, Florida, Texas, Michigan, Ohio, and

Pennsylvania (USGS, 2000b). In addition to active mines, the U.S. Bureau of Land Management estimates approximately 10,200 abandoned hardrock mines are located within the roughly 264 million acres under its jurisdiction. Estimates of abandoned mines on public and

private lands range from 80,000 to hundreds of thousands of small to medium-sized sites (DOI, Bureau of Land Management, 2002).

PROTECTED LANDS

Across the U.S., lands are protected against or for certain uses in a variety of ways by federal, state, and local land managers and by private

landowners. Local zoning ordinances, state and federal land management regulations, and land classifications are used to protect lands for

habitat and natural uses. Federal land management agencies protect land in several different use classifications that provide varying degrees

of protection. More than 4 percent of the nation is managed as wilderness. Of the 106 million acres of land now designated as federal

wilderness, more than half are in Alaska (Wilderness Information Network, 2002). Millions of acres of lands are also protected in the

National Park Service System, within the U.S. Fish and Wildlife Service refuge system, as USDA and Bureau of Land Management Wilderness

Study Areas, in National Forest Roadless Areas, in the National Trails System, as National Wild and Scenic Rivers, in National Recreation

Areas, in Research Natural Areas, and other areas. States also have established park systems, fish and wildlife areas, wilderness systems, 

and other areas of protected lands. Local government agencies also often manage parks. Conservation easements protect private lands by

providing restrictions from development in perpetuity. 

Indicators 

Extent of developed lands 

Extent of urban and suburban lands
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-9

The two indicators presented in this section provide an estimate of

the extent of developed land, with an estimate of urban and

suburban lands as a subset of developed lands. These estimates were

developed using different definitions and methodologies. The extent 

of “developed land” indicator uses a national statistical sample that

takes into account various development types. The “extent of urban

and suburban lands” indicator identifies densely developed areas

classified using remotely sensed satellite data. 

DEFINITIONS OF DEVELOPED AND URBAN/SUBURBAN LANDS 

U.S. Census Bureau Definitions 

Urbanized Areas and Urban Clusters. The Census Bureau describes urban areas as Urbanized Areas (UAs) and Urban Clusters (UCs).

These are designations for densely settled areas, which consist of core census block groups that have a population density of at least

1,000 people per square mile and other surrounding census blocks that have an overall density of at least 500 people per square mile. UAs

contain 50,000 or more people. UCs contain at least 2,500 people, but less than 50,000. Based on 2000 Census data, there are 466

UAs and 3,172 UCs comprising nearly 60 million acres (or 2.6 percent of the U.S. land area). These definitions and delineations of urban

areas are used by the Office of Management and Budget to delineate the Census Metropolitan Areas, including Metropolitan Statistical

Areas, which are used for various federal and state budget allocation purposes (U.S. Census Bureau, 2001).

USDA, NRCS, National Resources Inventory (NRI) Definitions

Developed land. A combination of land cover/use categories: Large urban and built-up areas, small built-up areas, and rural transportation land

(USDA, NRCS, 2000a).

Urban and built-up areas. A land cover/use category consisting of residential, industrial, commercial, and institutional land; construction sites; public administrative sites; railroad yards; cemeteries; airports; golf courses; sanitary landfills; sewage treatment plants; water

control structures and spillways; other land used for such purposes; small parks (less than 10 acres) within urban and built-up areas; 

and highways, railroads, and other transportation facilities if they are surrounded by urban areas. Also included are tracts of less than 10

acres that do not meet the above definition but are completely surrounded by urban and built-up land. Two size categories are recognized in the NRI: areas of 0.25 acre to 10 acres and areas of at least 10 acres. 

Large urban and built-up areas. A land cover/use category composed of developed tracts of at least 10 acres—meeting the 

definition of urban and built-up areas. 

Small built-up areas. A land cover/use category consisting of developed land units of 0.25 to 10 acres that meet the definition of

urban and built-up areas. 

Rural transportation land. A land cover/use category that consists of all highways, roads, railroads, and associated rights-of-way 

outside of urban and built-up areas, including private roads to farmsteads or ranch headquarters, logging roads, and other private

roads, except field lanes.

The Heinz Report Definitions

Urban and suburban lands. An area is considered to be urban/suburban if a majority of the lands within a 1,000 foot by 1,000 foot 

area (pixel) fall into one of the four "developed" land cover types classified in the NLCD (low-density residential, high-density residential,

commercial-industrial-transportation, or urban and recreational grasses). In outlying areas, clusters of pixels had to total at least 270 acres

to be considered urban/suburban. 
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3-10 3.1 Land Use Chapter 3 - Better Protected Land

Land development generally results in significant changes in other

land uses or cover types. This indicator provides a measure of how

much developed land exists, where it is, and how it has changed.

The indicator relies on national statistical data samples conducted

every five years by the USDA NRCS. 

What the Data Show

The NRI reports approximately 98 million acres of developed land

in the U.S., not including Alaska (USDA, NRCS, 2001). This figure

represents about 4.3 percent of the total land area. Exhibit 3-4

shows the distribution of non-federal developed lands nationwide.

Each dot on the map represents 15,000 acres. The map displays

the Census Metropolitan Area boundaries, which are larger in

western states due to the large size of many counties. States 

along the Northeast corridor have the highest percentages of

developed land, exceeding more than one-third of a state’s area 

in some cases.

Between 1982 and 1997, developed lands increased by 25 million

acres, primarily through conversion of croplands and forest lands

(USDA, NRCS, 2000a). This represents a 34.1 percent increase.

Developed lands as a percentage of the nation rose from 3.2 

percent in 1982 to 4.3 percent in 1997 (USDA, NRCS, 2000a).

The pace of land development between 1992 and 1997 was more

than 1.5 times the rate of the previous 10 years. The distribution

of changes in developed land varies nationwide, with extensive

changes in the eastern part of the country from south to north.

Indicator Extent of developed lands – Category 1

Exhibit 3-4: Extent of non-federal developed land, 1997 

Hawaii

98,251,700 acres of developed land

Metropolitan areas are defined as U.S. Census

Bureau Metropolitan Statistical Areas.

Source: USDA, Natural Resources Conservation Service. National Resources Inventory, 1997, revised December 2000: Acres of Developed Land, 1997. 2000.

(January 2003; http://www.nrcs.usda.gov/technical/land/meta/m4974.html).

Puerto Rico/U.S. Virgin Islands

Each red dot represents 

15,000 acres of 

developed land

95% or more

federal area

Metropolitan area

boundaries

Metropolitan area

central cities

Alaska 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-11

Exhibit 3-5 depicts the change in developed land (urban and 

suburban areas and rural transportation land) by watershed in the

1982 to 1997 time frame. 

Indicator Gaps and Limitations

The NRI data are limited in not providing data on Alaska and not

assessing development on federal lands, including 

recreational development and transportation infrastructure. 

Data Source

Acreage estimates and map data presented for this indicator are

from the National Resources Inventory, U.S. Department of

Agriculture, Natural Resources Conservation Service, 1997

(Revised December 2000). (See Appendix B, page B-18, for 

more information.)

Indicator Extent of developed lands – Category 1 (continued)

Exhibit 3-5: Land development patterns, 1982–1997

25,005,900 New Developed Acres

Source: USDA, Natural Resources Conservation Service. National Resources Inventory, 1997, revised December 2000: Land Development, 1982-1997. 2000. 

(January 2003; http://www.nrcs.usda.gov/technical/land/meta/m5009.html).

Hawaii

Puerto Rico/U.S. Virgin Islands

New Acres

50,000 or more

25,000 to 50,000 

15,000 to 25,000 

Less than 15,000

95% or more 

Federal area

Metropolitan areas

Alaska (no data) 

National Resources Inventory

The NRI is a longitudinal survey designed to assess conditions

and trends of soil, water, and related resources on non-federal

lands in the U.S. The NRI statistical sample involves approximately

300,000 sample units and 800,000 sample points on nonfederal lands. The sample is a stratified two-stage unequal 

probability design that can be modified to address specific

national survey goals or special studies. Stratification was developed county by county, based on the Public Land Survey System

(PLSS) where possible, and on latitude/longitude, Universal

Transverse Mercator Grid, or artificial superimposed lines when

necessary. The national sampling varies across strata and ranges

from 2 to 6 percent. The NRI measures numerous variables, which

are then extrapolated as national totals. Variables include the 

following: soil characteristics, earth cover, land cover and use, 

erosion, land treatment, vegetative conditions, conservation treatment needs, potential for cropland conversion, extent of urban

land, habitat diversity, and Conservation Reserve Program cover.

NRI sample data are generally reliable at the 95 percent 

confidence interval for state and certain broad sub-state area

analyses (Goebel, 1998). 
Farmlands represent one of the nation’s major ecological systems

and are discussed in Chapter 5, Ecological Conditions.(The Heinz

Center, 2002). As noted in the sidebar, on the following page, croplands, which can include pasturelands and haylands, are at the heart

of the farmland ecosystem. The broader “farmland landscape” also

includes other lands that are not actively used for crop, pasture, or

hay production. The composition of lands that surround croplands,

such as forests, wetlands, or built-up areas, are discussed further in

the “farmland landscape” indicator. 

The U.S. produces a wide range of food crops, grains, and other

agricultural products over vast areas of the country that are part of

the farmland landscape (see adjacent sidebar). Agricultural lands can

be thought of as all those lands that contribute to this production.

Other words such as farmland, cropland, pastureland, rangeland,

grazing land, or grassland are also used to describe aspects of 

agricultural lands. Some of these words define cover types, while

others define land use. The areas overlap but do not necessarily

coincide with each other. This situation creates challenges in establishing accurate estimates of extent. Under the discussion of the

agricultural land use indicator, an effort is made to distinguish the

various definitions and provide a measure of acreages. (Current 

definitions as used by the USDA NRCS NRI are shown in the sidebar

that follows.) 

3.1.2 What is the extent of

farmlands?

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3-12 3.1 Land Use Chapter 3 - Better Protected Land

Urban and suburban lands are considered a subset of developed

lands and one of the ecological systems described in Chapter 5,

Ecological Condition. These are highly developed areas and 

surrounding suburbs, including developed outlying areas above a

minimum size. Acreage estimates are based on an analysis of the

remotely sensed NLCD data conducted by the U.S. Geological

Survey (USGS), Areas of at least 270 acres that are substantially

covered with roads, buildings, concrete, and other hard surfaces

must be identified to be classified and counted as urban/suburban (The Heinz Center, 2002). This definition excludes smaller

built-up areas. 

What the Data Show

Urban and suburban ecological systems occupied 32 million acres

in the conterminous U.S. in 1992, or about 1.7 percent of that

land area (The Heinz Center, 2002). This estimate was derived

from a re-analysis of the 1992 NLCD. The analysis includes 

information on the amount and character of undeveloped land

within urban/suburban areas. Most of the lands designated urban

and suburban are in the South and Midwest, but they account for

less than 2 percent of the land in those regions. In the Northeast,

urban and suburban lands account for more than 5 percent of 

the landscape. 

Indicator Gaps and Limitations

The NLCD database is derived from a one-time interpretation

of satellite imagery of the nation from the early 1990s.

Although limited by the ability to detect land use remotely

based on spectral characteristics, NLCD data are available for

all of the conterminous U.S. Original estimates of the NLCD

indicated a total of 36.7 million acres of land in three different

“developed” land cover classifications (low density residential,

high density residential, and commercial/industrial/transportation) (The Heinz Center, 2002). 

Data Source

Acreages presented for this indicator are derived from a 

re-analysis of the National Land Cover Data, a product of the 

Multi-Resolution Land Characteristics Consortium, which is a partnership between the U.S. Geological Survey; the U.S. Department

of Agriculture, Forest Service; the National Oceanographic and

Atmospheric Administration; and the EPA. (See Appendix B, page

B-18 for more information).

Indicator Extent of urban and suburban lands – Category 2 

Indicators 

Extent of agricultural land uses

The farmland landscape
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Chapter 3 - Better Protected Land 3.1 Land Use 3-13

NRI Land Cover Definitions for Agricultural Land

Cropland. A land cover/use category that includes areas used for the production of adapted crops for harvest. Two subcategories of 

cropland are recognized: cultivated and noncultivated. Cultivated cropland comprises land in row crops or close-grown crops and also 

other cultivated cropland, such as hayland or pastureland in a rotation with row or close-grown crops. Non-cultivated cropland includes

permanent hayland and horticultural cropland. 

Conservation Reserve Program (CRP). A federal program established under the Food Security Act of 1985 to help private landowners

convert highly erodible cropland to vegetative cover for 10 years. 

Pastureland. A land cover/use category of areas managed primarily for the production of introduced forage plants for livestock grazing.

Pastureland cover may consist of a single species in a pure stand, a grass mixture, or a grass-legume mixture. Management usually consists

of cultural treatments: fertilization, weed control, reseeding or renovation, and control of grazing. For the NRI, it includes land that has a

vegetative cover of grasses, legumes, and/or forbs, regardless of whether it is being grazed by livestock. 

Rangeland. A land cover/use category on which the climax or potential plant cover is composed principally of native grasses, grasslike

plants, forbs or shrubs suitable for grazing and browsing, and introduced forage species that are managed like rangeland. This would include

areas where introduced hardy and persistent grasses, such as crested wheatgrass, are planted and such practices as deferred grazing, 

burning, chaining, and rotational grazing are used, with little or no chemicals or fertilizer being applied. Grasslands, savannas, many wetlands, some deserts, and tundra are considered to be rangeland. Certain communities of low forbs and shrubs, such as mesquite, chaparral,

mountain shrub, and pinyon-juniper, are also included as rangeland. 

(USDA, NRCS, 2000a) 

Aside from the challenges of defining types of agricultural land,

assessing the amount of land used for crops is an imperfect science,

given the seasonality of agricultural practices and changes in 

economics and technology. As with developed land, estimates vary

depending on the classification criteria and mapping or sampling

methodologies. Until the 1950s, the amount of agricultural land

needed to meet demands for food continued to grow, reaching a

peak of more than a billion acres of cropland and rangeland in the

mid 1960s. Since then, crop and farmland acreages have decreased

and increased in cycles, as both economics and technology have

changed demands and as production capabilities have increased.

Two indicators are considered on the following pages. The first

assesses the extent of land used to grow food crops and forage. The

second considers the farmland landscape, which includes not only

land used for agricultural production but also adjacent areas.
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3-14 3.1 Land Use Chapter 3 - Better Protected Land

Land can be used for a variety of agricultural purposes. Two 

general categories are differentiated in this discussion. The first

includes lands that are actively managed to cultivate food crops

or forage. This category comprises croplands, or lands that grow

perennial and annual crops such as fruits, nuts, grains, and vegetables; and pasturelands, or lands that are actively cultivated to 

produce forage for livestock. The second category includes lands

that may be used to produce livestock as an agricultural commodity, but are not planted, fertilized, or otherwise intensively 

managed. These livestock production lands may be called grazing

lands or rangelands and can include forest land, shrubland, and

grassland, which are described in the following sections. Livestock

production may also include concentrated animal feedlot 

operations, acreages of which are not included in this discussion.

What the Data Show

In 1997, the NRI identified nearly 377 million acres of cropland

and more than 32 million acres of Conservation Reserve Program

(CRP) land. CRP lands, as noted in the sidebar, are croplands that

are set aside (farmers are provided incentives) for up to 10 years

for conservation purposes, but that could be returned to crop

production if the program ceased. This total equals nearly 410

million acres of land currently growing or specifically identified

with the potential to grow crops in the U.S. (USDA, NRCS,

2000a) (Exhibit 3-6).

The NRI reports about 120 million acres of pastureland. As

defined in the sidebar, pastureland includes land that has a 

vegetative cover of grasses, legumes, and/or forbs, regardless of

Indicator Extent of agricultural land uses – Category 1

Exhibit 3-6: Extent of croplands, 1997

95% or more

Federal area

Puerto Rico/U.S. Virgin Islands

Each green dot represents 25,000

acres of cropland

Total acres: 376,997,900

Hawaii

Source: USDA, National Resources Conservation Service. National Resources Inventory, 1997, revised December 2000: Acres of Cropland. 2000.

(January 2003; www.nrcs.usda.gov/technical/land/meta/m4964.html).

Alaska

(no data) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-15

Indicator Extent of agricultural land uses – Category 1 (continued)

whether it is being grazed by livestock. It is usually managed to

produce feed for livestock grazing, using fertilization, weed 

control, and reseeding. Thus the total estimate from the NRI for

cropland, CRP land, and pastureland is 530 million acres.

The Heinz Center (2002), using four different sources of data,

estimated that cropland, including pasture and haylands, covered

between 430 and 500 million acres in 1997. For the most part,

the report did not include CRP lands in its estimates. According to

the 1992 NLCD, the U.S. had 510 million acres of agricultural land

in the 1990s (EPA, ORD, 1992). 

Grazing to support livestock production can potentially occur 

on pastureland, rangeland, and, in some cases, forest land. 

These lands can also be defined based on their cover type (e.g.,

grasslands, shrublands, or forested range). Not counting pastureland, the NRI identified nearly 406 million acres of non-federal

rangelands and another 62 million acres of non-federal forest land

that can be used for grazing livestock (USDA, NRCS, 2000a). In

addition, according to estimates generated by the Bureau of Land

Management, more than half of the federal land in the lower 48

states, or 244 million acres, is available for livestock grazing (DOI,

1994). The total of these estimates is 712 million acres of lands

that may be used for grazing, but are not cultivated. Adding in the

pastureland acreage results in 832 million acres of land that may

be used for grazing livestock nationwide (excluding Alaska).

Agricultural lands constantly shift among crop, pasture, range, and

forest land to meet production needs, implement rotations of land

in and out of cultivation, and maintain and sustain soil resources.

Within these shifts, however, trends indicate a gradual decrease in

cropland acreage. Between 1982 and 1997, cropland decreased

10.4 percent, from about 421 million acres to nearly 377 million

acres (Exhibit 3-7). Of this 44 million acre decrease, however,

30.4 million acres are now enrolled in the CRP, resulting an 13.6

million fewer acres of cropland as a result of conversion to other

land uses (USDA, NRCS, 2000a). During this same time frame,

pastureland area decreased 9.1 percent, or about 12 million acres

(USDA, NRCS, 2000a). The total change in acreage, considering

lands in the CRP was 23 million fewer agricultural land acres in

1997 than in 1982. 

Decreases in cropland have occurred particularly in the southern

and southeastern part of the U.S. The distribution of change in

cropland acreage is displayed in Exhibit 3-8. There are no 

comprehensive estimates of changes in acreages of grazing lands.

Indicator Gaps and Limitations 

A specific objective of the NRI is to assess changes in cropland.

Again, however, the ability to couple it with current remote sensing imagery would likely contribute to improved resolution and

national mapping of cropland types (See the discussion about

NRI data in the “Extent of Developed Land” indicator box).

There is no single, definitive, accurate estimate of the extent of

cropland. Estimates of the amount of land devoted to farming 

differ because different programs use different methods to

acquire, define, and analyze their data. Cropland is also a flexible

resource that is constantly being taken in and out of production.

The Heinz report used four different data sources to describe the

range of estimates. The four data sets are not fully consistent, and

comparisons are difficult to make. For example, the USDA

Economic Research Service (ERS) and Census of Agriculture data

include croplands in Alaska and Hawaii, while NRI does not. The

ERS data used in the Heinz report estimate included CRP lands,

while the Census of Agriculture and NRI estimates used by the

Heinz report did not (The Heinz Center, 2002). 

Data Sources

The data sources for this indicator are the National Resources

Inventory, U.S. Department of Agriculture, Natural Resources

Conservation Service, 1997 (Revised in December 2000);

Summary Report: 1997 National Resources Inventory (Revised

December 2000), U.S. Department of Agriculture, NRCS; and

Exhibit 3-7: Change in cropland, Conservation Reserve 

Program (CRP) land and pastureland, 1982-1997

Decrease = 23million acres

Millions of acres

0

100

200

300

400

500

600

1982 1987 1992 1997

Pastureland

Conservation Reserve Program

Cropland

Source: USDA, Natural Resources Conservation Service. 

Summary Report 1997 National Resources Inventory (revised December 2000). 2000.
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3-16 3.1 Land Use Chapter 3 - Better Protected Land

Draft Environmental Impact Statement, U.S. Department of the

Interior, Bureau of Land Management, 1994. The Heinz Center

estimates of cropland acreages are derived from the National Land

Cover Data, a product of the Multi-Resolution Land

Characteristics Consortium, 

which is a partnership between the U.S. Geological Survey; the

U.S. Department of Agriculture, Forest Service; the National

Oceanographic and Atmospheric Administration; and the EPA.

(See Appendix B, page B-19, for more information.)

Indicator Extent of agricultural land uses – Category 1 (continued)

Exhibit 3-8: Percent change in cropland area, 1982–1997

Increase > 25 

Percent Change

Puerto Rico/U.S. Virgin Islands

There was a -10.4% decrease in cropland

area between 1982 and 1997.

Hawaii

Source: USDA, Natural Resources Conservation Service. National Resources Inventory, 1997, revised December 2000: Percent Change in Cropland Area, 1982-1997. 2000.

(January 2003; www.nrcs.usda.gov/technical/land/meta/m5874.html).

Increase of 5 to 25 

Little change 

Decrease of 5 to 25

Decrease 25 

95% or more 

Federal area

Less than 5% cropland

Alaska

(no data) 
Grasslands and shrublands can be viewed as one of the major 

ecological systems of the U.S. and are discussed in Chapter 5,

Ecological Condition, (The Heinz Center, 2002). Grasslands and

shrublands can be used for grazing and, in that sense, overlap in

extent with agricultural land. As previously defined, pastureland and

rangeland are covered by grass and shrub species. This ecosystem is

one of the largest types in the U.S. and includes not only the 

grasslands and shrublands of the American West, but also coastal

meadows, grasslands and shrubs in Florida, mountain meadows, hot

and cold deserts, tundra, and similar areas in all states. 

Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-17

Examining the broader context of agricultural lands can provide

a better understanding of agricultural ecosystems. As previously

noted, the Heinz report defined this term as not only the lands

used to grow crops, but also the field borders, windbreaks,

small woodlots, grassland and shrubland areas, wetlands, farmsteads, and small villages and other built-up areas within or

adjacent to croplands. These covers/uses support not only

agricultural production, but provide habitat for a variety of

wildlife species as well. 

What the Data Show

The farmland landscape indicator describes the degree to which

croplands dominate the landscape and the extent to which other

lands are intermingled (The Heinz Center, 2002).

Croplands comprise about half of the farmlands in the East and

Southeast, while in the Midwest, almost three-quarters of the 

farmland ecosystem is cropland (The Heinz Center, 2002). Forests

make up the remainder of the farmland ecosystem in the East, 

wetlands the remainder in the Southeast, and both forests and

wetlands in the Midwest. In the West, about 60 percent of farmland ecosystem is cropland, with grasslands and shrublands 

dominating the remainder in the western and northern Plains areas.

Forests and grasslands/shrublands are about equal in the farmland

landscape for the non-cropland area of the South Central region.

In many U.S. areas, other land cover types are almost as prevalent

as croplands and can provide habitat for non-agronomic species.

Indicator Gaps and Limitations

This indicator uses satellite data from the early 1990s to describe

the farmland landscape. Remote sensing technology can underestimate dispersed land development that is denser than scattered

rural settlements, but not as dense as traditional “suburbs.”

Data Source

The National Land Cover Database, with 21 land cover classes,

was used to estimate the area coverage for the U.S. The NLCD is

based on remotely sensed imagery from the Landsat 5 Thematic

Mapper. Data are available from <www.usgs.gov/mrlcreg.html>.

(See Appendix B, page B-19, for more information.)

Indicator The farmland landscape – Category 2

3.1.3. What is the extent of

grasslands and shrublands?

Indicator 

Extent of grasslands and shrublands
EPA’s Draft Report on the Environment 2003 ■ Technical Document

There was an estimated 900 million to 1 billion acres of grasslands and shrublands in the lower 48 states before European

settlement (Klopatek, et al., 1979). By 1992, between 40 million

and 140 million acres had been converted to other uses. Many

pastures are managed in such a way that little of their original

grassland character remains, however. Thus, the area of relatively

unmanaged grasslands and shrublands has probably declined

more than the overall figures would indicate (The Heinz Center,

2002). One factor in the decline of grassland pasture and range

acreages since the 1960s is that forage productivity has

increased and the number of domestic animals has declined

(Vesterby, 2003).

What the Data Show

Based on remote sensing satellite data, it is estimated that grasslands and shrublands (including pasturelands and haylands) occupy about 861 million acres in the lower 48 states and 205 million

acres in Alaska, for a total of 1.066 billion acres or about 47 percent of the U.S. (not including Hawaii) (The Heinz Center, 2002)

(Exhibit 3-9). This estimate distinguishes 178 million acres of pasturelands and haylands, which are also considered to be part of

the farmland landscape, leaving 683 million acres of grasslands

and shrublands in the lower 48 states (The Heinz Center, 2002). 

Indicator Gaps and Limitations

NLCD was used to estimate extent of grasslands and shrublands in

the lower 48 states. Other data were estimated for Alaska. This is

a complicated and changing ecosystem that is subject to conversion to other uses. It would be useful to have better means to

characterize and track extent. 

Data Sources

The National Land Cover Database with 21 land cover classes, was

used to estimate the area coverage for the U.S. The NLCD is

based on remotely sensed imagery from the Landsat 5 Thematic

Mapper. Data are available from <www.usgs.gov/mrlcreg.html>.

Data for Alaska were estimated from a vegetation map of Alaska

by Flemming (1996), based on Advanced Very High Resolution

Radiometer remote sensing images with an approximate resolution

of 1 kilometer on a side (The Heinz Center, 2002). (See Appendix

B, page B-19, for more information.)

Indicator Extent of grasslands and shrublands – Category 2 

Exhibit 3-9: Extent of grasslands and shrublands, 1991 and 1992

Millions of acres

0

200

400

600

800

1000

Source: EPA, Office of Research and Development. Multi-Resolution 

Land Characteristics Consortium, National Land Cover Data. 1992. 

(February 19, 2003; http://www.epa.gov/mrlc/nlcd.html).

Source: Flemming, M.D. A Statewide Vegetation Map of Alaska Using a 

Phenological Classification of AVHRR Data. February 1996.

Area of grasslands and shrublands, lower 48 states Area of grasslands and shrublands, Alaska

Total

Shrublands

Grasslands

Pasture

Millions of acres

0

200

400

600

800

1000

1992 1991

Total

Shrublands

Tundra

3-18 3.1 Land Use Chapter 3 - Better Protected Land
Forests provide a range of important benefits to society. In addition

to providing wood products, such as paper and lumber, forest lands

help to purify air and water, mitigate floods and droughts, regulate

climate through storage of carbon dioxide, regenerate soils, provide

habitat for fish and wildlife, and support recreational opportunities.

Trends in the extent of forests are an important indicator of human

management of the landscape, since forest lands cover about onethird of the total U.S. land area. This section provides information on

the status and trends relating to the amount and management of

forest land. Additional information on the condition of forest land is

found in Chapter 5, Ecological Condition.

It is estimated that in 1630, 1.045 billion acres of forest land

existed in what would become the U.S. land area. (USDA, FS,

2001). Nearly 25 percent of these lands were cleared by the early

1900s, leaving 759 million acres in 1907. Since that time the total

amount of forest land nationwide, while changing regionally has

remained relatively stable, with an increase of 2 million acres

between 1997 and 2001.

What the Data Show 

There were an estimated 749 million acres of forest land in the

U.S. in 2001 (USDA, FS, 2002). In the period between 1987 and

2001, forest land acreage increased by about 11 million acres

(USDA, FS, 2002).

There have been regional changes in the amount of forest land

due to changing patterns of agriculture, development, and reversion to forests. Since the 1950s, forest lands in the northeast and

northcentral states have increased by almost 10 million acres,

while the South has lost about 11 million acres (USDA, FS, 2001).

Private forest lands are being converted to developed land uses

faster than any other land type (USDA, NRCS, 2001).

Forest land management varies greatly depending on differences

in ownership, management intent, and desired outcomes, ranging

from lands managed intact to protect water supplies, to harvesting

for timber production. About 55 percent of the nation’s forest

lands are in private ownership (USDA, FS, 2002). Most forest

lands are managed for a mix of uses, such as recreation, timber

harvest, grazing, and mining. In the southern and eastern U.S.,

most forest land is privately held in relatively small holdings, 

while in the Rocky Mountains and western U.S., most forest lan

d is in large blocks of public ownership in national forests 

(Exhibit 3-10). As previously noted, ownership affects how lands

are managed and used.

About 76 million acres, or 10 percent of the nation’s forests are

“reserved” and managed as national parks or wilderness areas

(USDA, FS, 2002). These estimates of reserves include state 

and federal parks and wilderness areas, but do not include 

conservation easements, areas protected by non-governmental

organizations, or most urban and community parks and reserves.

There are significant regional differences in the amount of forest

reserves. In the West, reserves are common, comprising nearly 18

percent of the total forest area. Much of the protected forest in

the West is in stands over 100 years old. Only 3 percent of 

eastern forests are in reserves such as parks and wilderness

(USDA, FS, 2001).

Indicator Extent of forest area, ownership, and management – Category 1

Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-19

Exhibit 3-10: Forest land ownership by region, 2001

Millions of acres

Total Private

Total Public

0

50

100

150

200

250

Pacific 

Coast

Rocky 

Mountains

North South

Source: USDA, U. S. Forest Service. Draft Resource Planning Act Assessment Tables. 

May 3, 2002 (updated August 12, 2002). 

(September 2003; http://www.ncrs.fs.fed.us/4801/FIADB/rpa_tabler/ 

Draft_RPA_2002_Forest_Resource_Tables.pdf).

Total U.S. Ownership

334.1

414.8

3.1.4 What is the extent of 

forest lands?

Indicator 

Extent of forest area, ownership, and management
EPA’s Draft Report on the Environment 2003 ■ Technical Document

About 66 million acres, or 9 percent of forest lands, are managed by private forest industries to produce timber (USDA, FS,

2002). Much of the remaining forest land receives less intensive

management activity, such as periodic harvest of mature timber.

Approximately 503 million acres of public and private forest

land are currently classified as timberlands by the USDA Forest

Service, an increase of 17 million acres since 1987 (USDA, FS,

2002). Approximately 63 percent of all U.S. timber harvesting is

conducted in the South, predominately from private lands. Total

timber harvest increased substantially between 1976 and 2001

in the East. In the West, after increasing steadily from 1952 to

1986, timber harvesting on public lands has declined sharply.

Public lands harvested nationwide dropped nearly 47 percent

from 1976 to 2001, to less than 2 billion cubic feet per year. In

the same time frame, private lands harvested increased by about

29 percent, from 11 to 14 billion cubic feet annually. (USDA, FS,

2002) (Exhibit 3-11).

Between 1980 and 1990, approximately 10 million acres were

harvested annually. Of the public and private forest lands

harvested for timber approximately 62 percent are selectively cut,

while 38 percent are clearcut. Most of the clearcutting occurs in

the South (USDA, FS, 2001).

Indicator Gaps and Limitations

Limitations for this indicator include the following:

■ The data for this indicator were collected by the USFS FIA 

program. Forest Industry and Analysis (FIA) currently provides

updates of assessment data every five years. Field data are 

collected on a probability sample of 125,000 forested sites and

extended to a remote sensing database on 450,000 sites by

the FIA program (Smith, et al., 2001). The resulting data on

extent have an uncertainty of 3 to 10 percent per million acres

for data reported since 1953. Regional estimates have errors of

less than two percent (The Heinz Center, 2002). 

■ The FIA data on reserved lands do not include information on

private lands that are legally reserved from harvest, such as

lands held by private groups for conservation purposes. In 

addition, other forest lands are at times reserved from harvest

because of administrative or other restrictions. 

Data Source

The data for this indicator are from the Draft Resource 

Planning and Assessment Tables, U.S. Department of Agriculture,

Forest Service, 2002. (See Appendix B, page B-20, for 

more information.)

Indicator Extent of forest area, ownership, and management – Category 1 (continued)

3-20 3.1 Land Use Chapter 3 - Better Protected Land

USDA Forest Service Definitions

Forest land. Land that is at least 10 percent stocked by forest

trees of any size, including land that formerly had tree cover

and that will be naturally or artificially regenerated. The minimum area for classification of forest land is 1 acre.

Timber land. Forest land that is capable of producing crops

of industrial wood (at least 20 cubic feet per acre per year in

natural stands) and not withdrawn from timber utilization by

statute or administrative regulation.

Reserved forest land. Forest land withdrawn from timber

utilization through statute, administrative regulation, or 

designation. (USDA, FS, April 2001)

Exhibit 3-11: Timber removals in the United States 

by owner group, 1952–2001

Billion cubic feet

Total Public

Total Private

0

5

10

15

20

1952 1962 1976 1986 1996 2001

Source: USDA, U. S. Forest Service. Draft Resource Planning Act Assessment Tables. 

May 3, 2002 (updated August 12, 2002). (September 2003; http://www.ncrs.fs.fed.us/ 

4801/FIADB/rpa_tabler/Draft_RPA_2002_Forest_Resource_Tables.pdf).
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-21

3.1.5 What human health effects

are associated with land use?

Land development patterns have direct and indirect effects on air

and water quality, which can then affect human health. For example,

the increased concentration of air pollutants in developed areas can

exacerbate human health problems like asthma. Increased storm

water runoff from impervious surfaces threatens the waterbodies that

urban and suburban residents rely on for drinking and recreation.

Development patterns can affect quality of life by limiting recreational opportunities, decreasing open space, and increasing vehicle miles

traveled and the amount of time spent on roads. Also, as discussed

later, agricultural land uses may expose humans to dust and various

chemicals. No specific indicators have been identified at this time. 

Land use also can have indirect effects on air quality. Low-density

patterns of development can often increase commutes—more 

people drive more miles. “Heat islands,” or domes of warmer air over

urban and suburban areas, are caused by the loss of trees and

shrubs and the absorption of more heat by pavement, buildings, and

other sources. Heat islands can affect local, regional, and global 

climate, as well as air quality. Agricultural land uses also result in

increased wind erosion. Degraded air quality can contribute to

human health issues such as asthma. Additional discussion of the

effects of land uses on air and water quality, human health, and the

environment is included in other chapters. 

Land use and land management practices change the landscape in

many ways that have both direct and indirect ecological effects. One

direct effect is the loss or conversion of acres of certain cover or

ecosystem types to other more human-oriented land uses such as

developed and agricultural uses. Indirect effects may include changes

in runoff patterns or increased soil erosion. 

The 25 million acre increase in developed land that occurred

between 1982 and 1997 came about through the conversion of

about 10 million acres of forest land, 7 million acres of agricultural

land, 4 million acres of pastureland, 4 million acres of rangeland, and

1 million acres of various other land cover types including wetlands

(USDA, NRCS, 1997). The causes of wetland loss are detailed in

Chapter 2, Purer Water. Changing land use patterns have also affected the extent and location of agricultural land. Between 1982 and

1997, approximately 13.6 million acres were converted from cropland

to other uses, including 7.1 million acres converted to developed

land. At the same time, approximately 4 million acres of rangeland

were converted to more intensive crop uses (USDA, NRCS, 2000a).

The conversions of land from agricultural, forest land, and rangeland

cover types to developed land can affect different species in specific

locations that depend on those cover types for habitat and food.

Species effects in various ecosystems are discussed in more detail in

Chapter 5, Ecological Condition. 

Land development also creates impervious surfaces through 

construction of roads, parking lots, and other structures. Impervious

surfaces contribute to non-point source water pollution by limiting

the capacity of soils to filter runoff. Impervious surface areas also

affect peak flow and water volume, which heighten erosion potential

and affect habitat and water quality (e.g., temperature increases).

They also affect ground water aquifer recharge. With sufficient storm

water infrastructure, higher population density in concentrated areas

can reduce water quality impacts from impervious surfaces by

accommodating more people and more housing units on less land

and developing water runoff systems that address issues of 

pollutants and sediment. Impervious surfaces developed as the result

of suburban or dispersed development patterns are more difficult to

mitigate, given that the effects are more dispersed and development

of runoff infrastructure is costly. 

Storm runoff from urban and suburban areas contains dirt, oils 

from road surfaces, nutrients from fertilizers, and various toxic compounds. Point source discharges from industrial and municipal 

wastewater treatment facilities can contribute toxic compounds and

heated water. Directing water through channels alters hydrologic flow

patterns. Increases in siltation and temperature can make stream

habitats unsuitable for native microinvertebrate and fish species.

Changes in the nutrient and chemical composition of stream water

can encourage growth of toxic algae and harmful organisms. The

types of crops planted, tillage practices, and various irrigation 

practices can limit the amount of water available for other uses, such

as municipal, industrial, and natural ecosystems. Livestock grazing in

riparian zones also can change landscape conditions by reducing

stream bank vegetation and increasing water temperatures, 

sedimentation, and nutrient levels. Runoff from pesticides, fertilizers,

and nutrients from animal manure can also degrade water quality. 

An indirect ecological effect of land use is the introduction of 

invasive species. Certain land use practices, such as overgrazing, land

conversion, fertilization, and the use of agricultural chemicals can

enhance the growth of invasive plants. Other human activities can

result in unstable or disturbed environments and encourage the

establishment of invasive plants. These activities include farming; 

creating highway and utility rights-of-way; clearing land for homes

and recreation areas such as golf courses; and constructing ponds,

reservoirs, and lakes (Westbrooks, 1998). Failure to manage invasive

species can lead to a major threat to native ecosystems. Non-native

species can alter fish and wildlife habitat, contribute to decreases in

Indicator

Sediment runoff potential from croplands and pasturelands

3.1.6 What ecological effects are

associated with land use?
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-22 3.1 Land Use Chapter 3 - Better Protected Land

Indicator Sediment runoff potential from croplands and pasturelands – Category 2

biodiversity, and create health risks to livestock and humans.

Introduction of invasive species on agricultural lands also can reduce

water quality and water availability for native fish and wildlife species;

clog lakes, waterways, and wetlands; weaken the ecosystem; and

adversely affect water treatment facilities and public water supplies.

Agricultural uses also can encourage the growth of invasive species

(USFWS, 2002). 

Land practices related to development, timber harvest, and

agriculture can affect soil quality both positively and negatively.

Some agricultural practices encourage soil conservation, minimizing

effects on soil resources. These practices include organic farming;

creating buffer strips in riparian zones; tree planting for windbreaks

or to decrease water temperature to improve fish habitat; soil erosion

control; integrated pest management; and precision pesticide and

fertilizer application technology. In contrast, other agricultural

activities promote soil compaction or result in loss of topsoil

through soil erosion. The indicator identified for this question

addresses the potential for sediment to run off from croplands and

pasturelands.

Soil erosion and transport can occur both by wind and by water

and have several major effects on ecosystems. Sediment is the

greatest pollutant in aquatic ecosystems—both by mass and

volume—and soil erosion and transport are the source (EPA, OW,

August 2002). Soil particles also can transport nutrients and

pesticides into aquatic systems where they may degrade water

quality. Although rates of erosion declined between 1982 and

1997 by about 1.4 tons/acre, more than one-quarter of all

croplands still suffer excessive wind and water erosion (USDA,

NRCS, 2000f). Excessive is defined as exceeding tolerable rates as

defined by USDA NRCS models (USDA, NRCS, 2000g).

Agricultural soil erosion decreases soil quality and can reduce 

soil fertility, and soil movement can make normal cropping

practices difficult (The Heinz Center, 2002). The loss of

productive top soil and organic matter affects the productivity of

agricultural lands. Further discussion on the extent and effects of

soil erosion can be found in Chapter 2, Purer Water, and in

Chapter 5, Ecological Condition.

What the Data Show

The potential for soil erosion and sediment runoff varies depending on specific land use, rainfall amounts and intensity, soil 

characteristics, landscape characteristics, cropping patterns, and

farm management practices. This indicator is the result of analyses

conducted by combining land cover, weather patterns, and soil

information in a process model that incorporates hydrologic

cycling, weather, sedimentation, crop growth, pesticide and nutrient loading, and agricultural management to estimate the amount

of sediment that could potentially be delivered to rivers and

streams in each watershed. The simulation estimated sheet and rill

erosion using a process model known as the Soil and Water

Assessment Tool (SWAT). 

SWAT is a model that is supported by the USDA Agricultural

Research Service. The sediment runoff data have been categorized

and are presented as low, medium, and high potential for runoff. 

Exhibit 3-12 displays the distribution of watersheds (based on 8-

digit hydrologic unit codes [HUCs]) nationwide and the potential

for sediment runoff (or delivery to rivers and streams) from croplands and pasturelands. The highest potential for sediment runoff

is concentrated in the central U.S., predominately associated with

the upper Mississippi River Valley and the Ohio River Valley. Most

of the western U.S. is characterized by low runoff potential (lower

percentage of cropland and pastureland). 

Indicator Gaps and Limitations

This indicator has several limitations for:

■ Sediment loads from non-agricultural land uses are not included

in these estimates. 

■ Estimates represent potential loadings to rivers and streams,

and do not represent in-stream loads. 

■ Gully erosion and channel erosion are not included.

Data Source

The Soil and Water Assessment Tool is a public domain model

actively supported by the U.S. Department of Agriculture,

Agricultural Research Service at the Grassland, Soil and Water

Research Laboratory in Temple, Texas 

(see http://www.brc.tamus.edu/swat/). 

(See also Appendix B, page B-22, for more information.) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.1 Land Use 3-23

Indicator Sediment runoff potential from croplands and pasturelands – Category 2 (continued)

Exhibit 3-12: Sediment runoff potential from croplands and pasturelands, 1990-1995

Watershed Classification (number of watersheds):

Low Potential for Delivery (528)

Moderate Potential for Delivery (1,048)

High Potential for Delivery (530)

Insufficient data (156)

Source: Walker, C. Sediment Runoff Potential, 1990-1995. August 24, 1999.

(September, 2002; http://www.epa.gov/iwi/1999sept/iv12c_usmap.html).

Puerto Rico/U.S. Virgin Islands

Hawaii

Alaska

(no data) 
3-24 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

3.2 Chemicals in the

Landscape

This section focuses on the extent, potential disposition, and effects

of chemicals used or managed on land. The production and use of

chemicals in the U.S. has increased over the last 50 years. The use

and release of chemicals can have various effects on human health

and ecological condition. Commercial and industrial processes such

as mining, manufacturing, and the generation of electricity all use

and release chemicals. Chemicals that control weeds, insects,

rodents, fungi, bacteria, and other organisms are called pesticides

and are commonly used on agricultural lands, as well as in urban,

industrial, and residential settings. Fertilizers—supplements to

improve plant growth—are also used extensively in a variety of 

settings. Pesticides and fertilizers have contributed to high 

agricultural productivity levels in the U.S.

EPA began monitoring the production and importation of industrial

chemicals in 1977 through the Toxics Substances Control Act

Chemical Inventory, which presently identifies more than 76,000

chemicals used in U.S. commerce. Nearly 10,000 of these chemicals

are produced or imported in quantities greater than 10,000 pounds

per year (excluding inorganics, polymers, microorganisms, naturally

occurring substances, and non-isolated intermediaries). About 3,100

of these chemicals are produced or imported in quantities exceeding

1 million pounds per year. Associated annual production/import 

volumes increased by 570 billion pounds (9.3 percent) to 6.7 

trillion pounds between 1990 and 1998 (EPA, OPPTS, 2002). 

The questions posed in this section consider the amounts and types

of chemicals released to the landscape, addressing toxic substances,

pesticides, and fertilizers. The discussion also looks at the potential

for chemicals to move from their use on land to places where humans

and other organisms can be exposed to them. In this context, 

questions also address what is currently known about health and

ecological effects from exposure to chemicals used on land. 

The six questions considered in this section are:

■ How much and what types of toxic substances are released into

the environment?

■ What is the volume, distribution, and extent of pesticide use?

■ What is the volume, distribution, and extent of fertilizer use?

■ What is the potential disposition of chemicals from land?

■ What human health effects are associated with pesticides, 

fertilizers, and toxic substances?

■ What ecological effects are associated with pesticides, fertilizers, 

and toxic substances?

The primary sources of data for this section are the EPA Toxics

Release Inventory (TRI), describing quantities of toxic chemical

releases; pesticide use estimates (based on sales) from both EPA and

the non-profit National Center for Food and Agricultural Policy

(NCFAP); data from the USDA’s Agricultural Resources and

Environmental Indicators report published in 2000 on the volume,

distribution, and extent of fertilizer use (see Appendix B); and data

from the USDA Pesticide Data Program on pesticide residues found

on food samples.

Many industries release toxic substances into the air, soil, and water

through their manufacturing and production activities. Under the

Emergency Planning and Community Right-to-Know Act of 1986 and

the Pollution Prevention Act of 1990, most facilities are required to

calculate and report to EPA and states their release and other waste

management quantities of more than 650 toxic chemicals and chemical categories. Intended uses of this information include helping

communities prepare for chemical spills and similar emergencies and

educating the public on industries’ release and other waste management practices for toxic chemicals. EPA makes these toxic release

data available to the public annually via the Toxics Release Inventory

(TRI) Public Data Release Report.

The indicator identified for this question addresses quantity 

and type of toxic chemicals released and managed as waste as 

well as trends.

Indicator

Quantity and type of toxic chemicals released and managed

EPA’s Draft Report on the Environment 2003 ■ Technical Document

3.2.1 How much and what types 

of toxic substances are released

into the environment?
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-25

The data collected in TRI represent only part of a broader

universe of chemicals used and released into the environment. 

TRI includes a large amount of information on a range of

categories of toxic chemicals, including many arsenic, cyanide,

dioxin, lead, mercury, and nitrate compounds and provides

information on the amount and trends in releases and

management of chemicals, including recycling, recovery, and

treatment. TRI data cover releases from reporting facilities in all

parts of the country and can be searched for releases within

individual zip codes. All data presented below can be found in 

the EPA 2000 Toxics Release Inventory Public Data Release Report

(EPA, OEI, May 2002).

What the Data Show

Releases to the environment for all EPA-tracked TRI chemicals

from nearly 23,500 facilities totaled 7 billion pounds in 2000. Of

these releases, 58 percent were to land, 27 percent were to air, 4

percent each were to water and underground injection at the 

generating facility, and 7 percent were chemicals disposed of 

off-site to land or underground injection. Three industries

accounted for most of the releases: metal mining (27 facilities)

accounted for 47 percent, manufacturing industries (21,352 

facilities) for 32 percent, and electric utilities (706 facilities) for

16 percent. The remaining 5 percent was split among hazardous

waste/solvent recovery, coal 

mining, petroleum terminals/bulk

storage, and chemical wholesale

distributors (Exhibit 3- 13).

Between 1998 and 2000, the

total amount of toxic releases as

estimated by the TRI decreased

by approximately 409 million

pounds, or 5.5 percent. Of that

total, releases to land decreased

approximately 276 million

pounds. Decreases in the 

releases by certain industries

(e.g., manufacturing and metal

mining) account for most of the

overall decrease between 1998

and 2000. A few industries 

(e.g., hazardous waste/solvent

recovery, coal mining, and chemical wholesale distributors)

increased their releases during

this time period. Off-site releases

from production increased by 75 

million pounds in the 1998 to

2000 time frame (Exhibit 3-14). 

Indicator Quantity and type of toxic chemicals released and managed – Category 2 

Source: EPA, Office of Environmental Information. 2000 Toxics Release Inventory 

(TRI) Public Data Release Report. May 2002.

Exhibit 3-13: Total toxic release inventory 

(TRI) releases by industry, 2000

(Total = 7 billion pounds)

Metal Mining: 47%

Chemical Wholesale 

Distributors: <1%

Coal Mining: <1%

Petroleum Terminals/ 

Bulk Storage: <1% Hazardous Waste/ 

Solvent Recovery: 4%

Electric Utilities: 16%

Manufacturing 

Industries: 32%

Exhibit 3-14: Toxics release inventory (TRI) total releases and change by industry, 1998–2000

Source: EPA, Office of Environmental Information. 2000 Toxics Release Inventory (TRI) Public Data Release Report. May 2002.

Billions of pounds Billions of pounds

Millions of pounds

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1998 1999 2000 1998 1999 2000 1998 1999 2000 1998 1999 2000

Transfers Off-Site to Disposal

On-Site Land Releases

Underground Injection

Surface Water Discharges

Total Air Emissions

Metal Mining Electric Utilities Hazardous Waste/Solvent 

Recovery

0

2.0

4.0

6.0

8.0

1998 1999 2000

Yearly Totals Across Industry Change by Industry, 1998–2000

-300

-250

-200

-150

-100

-50

0

50

Hazardous 

Waste/Solvent 

Recovery

Electric 

Utilities

Metal

Mining

Manufacturing 

Industries See key above

Manufacturing Industries
3-26 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

Indicator Quantity and type of toxic chemicals released and managed – Category 2 (continued)

The seven billion pounds of chemicals actually released into the

environment (air, water, and land) are a subset of toxic chemicals

managed and tracked in TRI. Another 31 billion pounds of toxic

chemicals were managed as waste in 2000. Nearly all (>99 percent) of these toxic chemicals were production related, Of the 31

billion pounds, 50 percent was treated, 39 percent was recycled,

and 11 percent was burned for energy recovery.

The total amount of toxic chemicals managed as waste during the

three-year period of 1998 to 2000 increased by almost 29 

percent, a net increase of 8.4 billion pounds (Exhibit 3-15). Two

industries in the southeastern U.S., printing/publishing and chemicals and allied products, accounted for most of this increase.

Between 1998 and 2000, the chemicals recycled increased by

more than 12 percent (1.3 billion pounds). In contrast, the 

quantities of chemicals combusted for energy recovery decreased

4.1 percent. 

The TRI data are also used to support EPA’s National Waste

Minimization Partnership Program, which focuses on reducing or

eliminating the generation of hazardous waste containing any of

30 Waste Minimization Priority Chemicals (WMPC). These chemicals are found in hazardous waste and are documented contaminants of air, land, water, plants and animals. EPA has tracked 17 of

these chemicals since 1991 and reports that WMPC generation

quantities have been steadily declining since 1993 (Exhibit 3-16).

Overall, between 1991 and 1998, the generation of WMPC in

industrial hazardous and solid waste decreased by 44 percent. 

Indicator Gaps and Limitations

The TRI data do not reflect a comprehensive total of toxic 

releases nationwide. Although EPA has added to the number of

industries (SIC codes) that must report, the TRI program does

not cover all releases of chemicals from all industries. Second,

industries are not required to report the release of several types

of toxic chemicals, because these chemicals are not included in

the TRI list. Third, facilities that do not meet the TRI reporting

requirements (those with fewer than 10 full-time employees or the

Waste Minimization Priority Chemicals

Organic chemicals and chemical compounds: 

*1,2,4-Trichlorobenzene

1,2,4,5-Tetrachlorobenzene

*2,4,5-Trichlorophenol

4-Bromophenyl phenyl ether

Acenaphthene

Acenaphthylene

*Anthracene

Benzo(g,h,i)perylene

*Dibenzofuran

Dioxins/Furans (considered one chemical on this list)

Endosulfan, alpha & Endosulfan, beta (considered one chemical on this list)

Fluorene

*Heptachlor & Heptachlor epoxide (considered one chemical

on this list)

*Hexachlorobenzene

*Hexachlorobutadiene

*Hexachlorocyclohexane, gamma-

*Hexachloroethane

*Methoxychlor

*Naphthalene

PAH Group (as defined in TRI)

Pendimethalin

Pentachlorobenzene

*Pentachloronitrobenzene

*Pentachlorophenol

Phenanthrene

Pyrene

*Trifluralin

Metal and Metal Compounds:

*Cadmium

*Lead

*Mercury

(*17 chemicals tracked since 1991)

Note: The data shown as "Quantity Released" vary from the data in Exhibit 3-14 

because some facilities include off-site transfers for disposal to other TRI facilities 

that then report the amount as on-site release.

Source: EPA, Office of Environmental Information. 2000 Toxics Release Inventory 

(TRI) Public Data Release Report. May 2002.

Exhibit 3-15: Trends in toxic chemicals 1998–2000

Billions of pounds

0

5

10

15

20

25

30

35

40

1998 1999 2000

Energy Recovery

Quantity Treated

Quantity Released

Recycled

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

employee equivalent, or those not meeting TRI chemical-specific

reporting threshold amounts) are not required to report their

releases and therefore are not included as part of the total. Finally,

facilities report their release and other waste management data to

TRI using monitoring data, emission factors, mass balance

approaches and engineering calculations. EPA does not mandate

monitoring of releases, although many industries do conduct

monitoring. Various estimation techniques are used when monitoring data are not available. EPA has published estimation guidance

for the regulated community, but not all industrial facilities use

consistent estimation methodologies, and variations in reporting

may result. With approximately 76,000 different types of chemicals in existence, and new ones constantly being developed, the

challenge is to ensure that those that are likely to pose the 

greatest hazards are tracked and managed.

Data Source

The data source for this indicator is EPA, Toxics Release Inventory,

2000. (See Appendix B, page B-20, for more information.)

Indicator Quantity and type of toxic chemicals released and managed – Category 2 (continued)

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-27

Exhibit 3-16: Trends in toxics release inventory (TRI) Waste 

Minimization Priority Chemicals (WMPC), 1991–1998 Millions of pounds

0% +1%

-28%

-36%

-44%

Source: EPA, Office of Solid Waste and Emergency Response. 

Waste Minimization Trends Report (1991-1998). September 2002.

50

0

100

150

200

1991 1993 1995 1997 1998

Pesticides are substances or mixtures of substances intended for 

preventing, destroying, repelling, or mitigating plant or animal pests.

Conventional pesticides include herbicides, plant growth regulators,

insecticides, fungicides, nematicides, fumigants, rodenticides, molluscicides, aquatic pesticides, and fish/bird pesticides. Most pesticides

create some risk of harm to humans, animals, or the environment

because they are designed to kill or otherwise adversely affect living

organisms. At the same time, pesticides are useful to society because

of their ability to kill potential disease-causing organisms and control

insects, weeds, and other pests.

Currently, no reporting system provides information on the volume,

distribution, and extent of pesticide use nationwide across all 

sectors. Estimates, however, of total pesticide use have been developed based on available information such as crop profiles, pesticide

sales, and expert surveys. Several of these data sets are collected by

the private or non-profit sectors rather than federal agencies. 

EPA’s recent Pesticide Industry Sales and Usage Report estimates show

that conventional annual pesticide use declined by about 15 percent

between 1980 and 1999. This change has not been steady; in 1999,

pesticide use was higher than it was in the early 1990s. Of the three

sectors of pesticide use assessed in EPA estimates (agricultural, 

industry-commercial-government, and home-garden), the industrialcommercial-government use of pesticides has seen the most steady

decline over this 20-year period. EPA estimates show that in 1999, 

agricultural pesticide use accounted for nearly 77 percent (956 million

pounds) of all pesticide use; home and garden use was 11 percent 

(140 million pounds); and industrial, commercial, and government 

use was nearly 12 percent (148 million pounds) of total conventional 

pesticide use (1244 million pounds). These estimates do not 

include wood preservatives, biocides, and chlorine/hypochlorites 

(EPA, OPPTS, 2002).

An important class of pesticides—insecticides—has undergone 

significant use reduction in the last 5 years. Insecticides, as a class,

tend to be the most acutely toxic pesticides to humans and wildlife.

The number of individual chemical treatments per acre, referred to 

as “acre-treatments,” for insecticides labeled “danger for humans”

has undergone a 43 percent reduction in use from 1997 to 2001.

Over the same period, acre-treatments for insecticides labeled

“extremely or highly toxic to birds” have been reduced by 

50 percent, and insecticides labeled “extremely or highly toxic to

aquatic organisms” have been reduced by 23 percent (EPA, OPP,

2001). The indicator identified for this question specifically 

addresses agricultural pesticide use.

Indicator

Agricultural pesticide Use 

3.2.2 What is the volume,

distribution, and extent of

pesticide use? 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-28 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

Indicator

Building on EPA and USDA estimates, as well as on pesticide use

surveys, the National Center for Food and Agricultural Policy

(NCFAP), a private, non-profit, research organization, has 

established a pesticide use database that provides estimates of

agricultural pesticide use by chemical, crop, and state. 

What the Data Show

According to NCFAP, and as shown in Exhibit 3-17, total

agricultural pesticide use increased from 892 to 985 million

pounds between 1992 and 1997. (EPA reports a similar increase in

use of all pesticides in this same time frame, and a leveling of use

between 1997 and 1999.) (EPA, OPPTS, 2002). Approximately

half of these agricultural pesticides are herbicides used to control

weeds that limit or inhibit the growth of the desired crop. While

many pesticides are synthetic chemicals, some biopesticides, such

as Bacillus thuringiensis, are also broadly used and are key

components of organic farming programs. 

The 1997 NCFAP summary report shows that more pesticides are

used on corn than on any other crop. At the same time, corn is

planted on more acres than any other single crop. It is also most

effectively treated with a combination of chemicals that are

applied in high quantities per acre. 

Oil, most often applied as a spray, is used in greater quantities

than any other pesticide across all crops. In the context of the

NCFAP report, “oil” includes plant oil extracts with insecticidal

properties, vegetable oils that work by smothering pests, and

petroleum derivatives used as solvents and insecticides. Sulfur—

through its broad applicability as an insecticide, fungicide, and

rodenticide—and atrazine, largely due to its use with corn, are

the next two most commonly used chemicals. 

Indicator Gaps and Limitations

Limitations for this indicator include the following:

■ The data quality of the NCFAP national pesticide use database

is unknown. The database is not a direct record based on

reports of actual usage and application. Some of the database

estimates are derived from surveys of farmers, and others are

expert opinions from knowledgeable extension service specialists. Also, because of the absence of data for many states and

crops, many records have been assigned based on the data

from a nearby state. It is unclear how accurate these sources

and procedures are. The 1997 summary report for the database

carefully makes no claims to statistical accuracy because of the

variety of sources and techniques for estimation of chemical

usage. Several federal agencies, however, use the information,

and NCFAP has received funding from USDA to update the 

pesticide use database for 2002 (Gianessi and Marcelli, 2000).

■ NCFAP data only report on the agricultural use of pesticides,

which leaves out other commercial non-agricultural and residential applications. Additional data would be advantageous for

tracking these uses of pesticides.

Data Source

The data source for this indicator is the National Center for Food

and Agricultural Policy’s Pesticide Use Database, 2000. (See

Appendix B, page B-21, for more information.)

Agricultural pesticide use – Category 2

Source: Gianessi, L.P., and M.B. Marcelli. Pesticide Use in U.S. Crop Production: 1997, 

National Summary Report. November 2000.

Exhibit 3-17: Pesticide use in crop 

production, 1992 and 1997

0

200

400

600

800

1000

1200

1992 1997

Millions of pounds of active ingredient per year

892 Total

985 Total

Other chemicals

Other conventionals

Insecticides

Herbicides

Fungicides
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-29

Most data on the volume and distribution of fertilizer use are

based on sales data collected by USDA. Usage is concentrated

heavily in the midwestern states where agricultural production—

particularly that of corn—is greatest. 

What the Data Show

According to the 2000 USDA Agricultural Resources and Environmental

Indicators Report, the use of nitrogen, phosphorus, and potash—the

most prevalent supplements used in fertilizers for commercial farming—rose from 7.5 million nutrient tons in 1961 to 23.7 million tons

in 1981. Although aggregate use dipped in 1983, it increased most

recently between 1996 and 1998 to more than 22 million nutrient

tons (Daberkow, et al, 2003) (Exhibit 3-18). 

Indicator Gaps and Limitations

Several limitations are associated with this indicator:

■ The data that do exist are based primarily on sales information

and use estimates. Gross sales data are not necessarily a reflection of fertilizer usage, nor do they convey any information

about the efficiency of application of various nutrients. 

■ A variety of factors such as weather and crop type influence the

amount of fertilizer used by farmers from year to year. A

decrease in usage over time may be due to a reduced reliance

on these chemicals or a change in crop rotation, weather, or

other factors, and may not be permanent. 

■ These data do not necessarily reflect residential fertilizer use.

Data Source

The data source for this

indicator is the Agricultural

Resources and Environmental

Indicators Report, U.S.

Department of Agriculture,

Economic Research Service,

2000. (See Appendix B,

page B-21, for more 

information.)

Indicator Fertilizer use – Category 2

Fertilizers have contributed to an increase in commercial agricultural

productivity in the U.S. throughout the latter half of the 20th 

century. Using fertilizers and soil amendments, farmers have successfully enhanced the productivity of marginal soils and shortened

recovery times for damaged areas. Similar to pesticide use, however,

the increasing use of commercial fertilizers in agriculture has 

consequences for human health and ecological condition. Between

World War II and the early 1980s, commercial fertilizer use increased 

consistently and significantly (Battaglin and Goolsby, 1994).

Fertilizer use patterns today are greatly influenced by crop patterns,

economic and climatic factors, and crop reduction programs implemented by local and federal government agencies (Council on

Environmental Quality, 1993). The indicator identified for this 

question specifically addresses the volume, distribution, and extent

of fertilizer use.

Source: Daberkow, et al. Agricultural Resources and Environmental Indicators: Nutrient Use and Management. February 2003. Millions of nutrient tons

Total

Nitrogen

Phosphorus

Potash

0

5

10

15

20

25

1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998

Exhibit 3-18: Use of fertilizer, 1960–1998

Indicator

Fertilizer use 

3.2.3 What is the volume,

distribution, and extent of

fertilizer use?
3-30 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

An indication of the amount of pesticides that are detectable in

the U.S. food supply provides information about the disposition

of some chemicals. Food is one of the pathways through which

people can be exposed to the effects of pesticides. USDA has

maintained a Pesticide Data Program (PDP) since 1992 that 

collects data on pesticide residues on fruits, vegetables, grains,

and in dairy products at terminal markets and warehouses.

Thousands of samples have been analyzed for more than 100 

pesticides and their metabolites on dozens of commodities.

Samples are collected by USDA immediately prior to these 

commodities being shipped to grocery stores and supermarkets.

They are then prepared in the laboratory as if for consumption

(e.g., washed, peeled, cored, but not cooked) so that samples are

more likely to reflect actual exposures. Pesticide residue levels 

are then measured.

What the Data Show

The Department of Agriculture's Pesticide Data Program (PDP)

measures pesticide residue levels in fruits, vegetables, grains, and

dairy products from across the country, sampling different 

commodities each year. In 2000, PDP collected and analyzed a

total of 10,907 samples: 8,912 fruits and vegetables, 178 rice,

716 peanut butter, and 1,101 poultry tissue samples which originated from 38 States and 21 foreign countries. Approximately 80

percent of all samples were domestic, 19 percent were imported,

Indicator Pesticide residues in food – Category 1

Disposition describes the potential for chemicals and nutrients to

move from their location of use or origin to a place in the environment where humans and other organisms can be exposed to them.

People can be affected by these chemicals and nutrients when

exposed to them through foods, drinking water supplies, or in the 

air they breathe. The environment can be affected when these chemicals accumulate on land or enter the water. A significant challenge

lies in tracking the movement of pesticides and fertilizers in the 

environment and then correlating their existence in water or air to

health or environmental effects. These chemicals often move 

through the environment and react in ways that are difficult to track

and understand. 

Pesticide contamination of ground water is a potential problem when

leachable pesticides are applied to soils. Soil leaching potential can

be determined by assigning rankings to organic matter, clay content,

and acidity, which are the three main factors controlling pesticide

leaching through soils (Hellkamp, et al., 1998). Pesticide-leaching

potential is a measure of how tightly and quickly a pesticide binds to

organic particles and is determined by the leaching potential of the

pesticide itself, the pesticide’s persistence, and the rate and method

of application. Some analysis of the pesticide leaching risk based on

these variables has been conducted in the mid-Atlantic region,

showing that relatively little acreage has a high potential for leaching. Other variables should also be considered in assessing the risk

of pesticide leaching including precipitation, antecedent soil 

moisture conditions, soil hydraulic conductivities and permeability,

and water table depths. 

Under ideal circumstances, crops would take up the vast majority of

nutrients that are applied as fertilizers to soil, but many factors,

including weather, overall plant health, and pests, affect the uptake

ability of crops. When crops do not use all applied nutrients, residual concentrations of nutrients and other components of chemical

fertilizers remain in the soil and can become concentrated in ground

water and surface water. The USGS National Water Quality

Assessment provides one measure of these chemical concentrations

in waterbodies based on samples from 36 major river basins and

aquifers (see Chapter 2, Purer Water). Calculating residual concentrations (known as the “residual balance”) for agricultural areas 

provides an understanding of the potential risks fertilizer use poses

to local environmental conditions. If the residual balance is positive,

then excessive nutrients may exist and present an ecological risk. 

If it is negative, then plants are taking up not only the amount of

nutrient added by the fertilizer but others already present in the 

soil and atmosphere. In this case, the soil might be depleted over

time (Vesterby, 2003). 

Four indicators are considered on the following pages, one that

measures the actual presence of chemicals in food, and three that

assess the potential for pesticides and nutrients to runoff the land. 

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Indicators 

Pesticide residues in food 

Potential pesticide runoff from farm fields

Risk of nitrogen export

Risk of phosphorus export

3.2.4 What is the potential

disposition of chemicals from

land?
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-31

and less than 1 percent were of unknown origin. Overall, 

approximately 42 percent of all samples contained no detectable

residues, 22 percent contained 1 residue, and 35 percent contained more than 1 residue. Detectable residues are not inherently

violations of regulatory tolerances. Residues exceeding the 

pesticide tolerance were detected in 0.2 percent of all composite

samples. Residues with no tolerance level were found in 1.2 

percent of all samples. These residues were detected at low 

concentrations and may be due to spray drift, crop rotations, or

cross contamination at packing facilities. PDP reports these 

findings to the Food and Drug Administration.

Indicator Gaps and Limitations

Limitations for this indicator include the following:

■ The PDP does not sample all commodities over all years, so

some gaps in coverage exist. For example, a specific commodity

might be sampled each year for a two or three year period and

then not be sampled for two or more years before being 

re-sampled during a subsequent period. Differences in the percent of detections for any given class of pesticides might not

be due to an increase (or decrease) in the predominance of

detectable residues, but might simply reflect the changing

nature and identity of the commodities selected for inclusion in

any given time frame (given that each PDP “market basket” of

goods differs to some extent over time). 

■ The PDP has the ability to detect pesticide residues at 

concentrations that are orders of magnitude lower than those

determined to have human health effects. The simple presence

of detectable pesticide residues in foods should not be 

considered indicative of a potential health concern (USDA,

AMS, 2002).

Data Source

The data source for this indicator is the Pesticide Data Program:

Annual Summary Calendar Year 2000, U.S. Department of

Agriculture, Agricultural Marketing Service. (See Appendix B, 

page B-21, for more information.)

Indicator Pesticide residues in food – Category 1 (continued)
EPAs Draft Report on the Environment 2003 ■ Technical Document

3-32 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

Indicator Potential pesticide runoff from farm fields – Category 2

This indicator identifies the potential for movement of agricultural

pesticides by surface water runoff in watersheds nationwide. The

indicator represents potential loss at the edge of a field based on

factors that are known to be important determinants of pesticide

loss, including: 1) soil characteristics, 2) historical pesticide use,

3) chemical properties of the pesticides used, 4) annual rainfall

and its relationship to runoff, and 5) major field crops grown

using 1992 as a baseline. Watersheds with high scores (i.e., the

“high potential for delivery” class) have a greater risk of pesticide

contamination of surface water than do those with low scores 

(i.e., the “low potential for delivery” class). (See Section 3.1.6 for

more on runoff categories.)

Calculations for watershed pesticide runoff potential are based on

a National Pesticide Loss Database, that uses the chemical fate

and transport model GLEAMS (Groundwater Loading Effects of

Agricultural Management). GLEAMS is a model that estimates 

pesticide leaching and runoff losses using the following as inputs:

soil properties, field characteristics (e.g., slope and slope length),

management practices, pesticide properties, and climate. GLEAMS

estimates were generated for 243 pesticides applied to 120 

specific soils; the estimates are for 20 years of daily weather for

each of 55 climate stations distributed throughout the U.S.

(Knisel, 1993).

Exhibit 3-19: Potential pesticide runoff from farm fields, 1990–1995

Watershed Classification (number of watersheds):

Low Potential for Delivery (394)

Moderate Potential for Delivery (788)

High Potential for Delivery (395)

Insufficient data (685)

Source: USDA, Natural Resources Conservation Service. National Resources Inventory. 1992; Gianessi, L.P., and J.E. Anderson. Pesticide Use in US Crop 

Production: National Data Report. February 1995; Goss, Don W. Pesticide Runoff Potential, 1990-1995. August 24, 1999. (September 2002; 

http://www.epa.gov/iwi/1999sept/iv12a_usmap.html).

Puerto Rico/U.S. Virgin Islands

Hawaii

Note: Alaska is not covered by the National Resources Inventory.

Alaska 

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-33

Chemical use for 13 different crops taken from the National

Pesticide Use Database was estimated for 1990-1993 (Gianessi

and Anderson, 1995). A total of 145 pesticides were included in

the derivation of the pesticide runoff indicator (using the joint set

of pesticides from the National Pesticide Use Database and the

National Pesticide Loss Database for the 13 crops). Estimates of

percent of acres treated and average application rates were imputed to the NRI sample points by crop and state. Each NRI sample

point where corn was grown in Iowa, for example, included chemical use for 22 of the pesticides Gianessi and Anderson reported

were used on corn in Iowa. The simulation assumed that each 

pesticide was applied at the average rate for the state. In reality,

pesticide use varies widely from field to field. The simulation thus

reflects general pesticide use patterns to provide an indication of

where the potential for loss from farm fields is the greatest.

The total loss of pesticides from each representative field was

estimated by 1) multiplying the estimate of percent loss per

acre by the application rate to obtain the mass loss per acre

for each pesticide, 2) calculating the number of acres treated

for each pesticide by multiplying the estimate of percent acres

treated by the number of acres associated with the sample

point, 3) multiplying the number of acres treated by the mass

loss per acre to obtain the mass loss for the representative

field for each pesticide, and 4) summing the mass loss estimates for all the pesticides.

Watershed scores were determined by averaging the scores 

for the NRI sample points within each watershed. The average

watershed score was determined by dividing the aggregate 

pesticide loss for the watershed by the number of acres of 

non-federal rural land in the watershed. Dividing by the acres 

of non-federal rural land provides a watershed level perspective

of the significance of pesticide loss.

What the Data Show

Exhibit 3-19 shows the distribution of watersheds and the 

potential for pesticide runoff nationwide. The highest potential for

agricultural pesticide runoff is concentrated in the central U.S.,

predominately associated with the upper and lower Mississippi

River Valley and the Ohio River Valley.

Indicator Gaps and Limitations

The following limitations are associated with this indicator:

■ The indicator estimates only the potential for pesticides to run

off farm fields. It does not estimate actual pesticide loss.

Research has shown that pesticide loss from farmlands can be

substantially reduced by management practices that enhance

the water-holding capacity and organic content of the soil,

reducing water runoff. Where these practices are being used,

the potential loss measured by this indicator will be overestimated because the practices are not considered in the

analysis. 

■ The indicator does not include croplands used for growing

fruits, nuts, and vegetables. Thus, watersheds with large 

acreage of these crops will have a greater risk of water 

quality contamination than shown by this indicator. 

■ For each field, pesticide usage was assumed as an average 

for the state, when actual use varies widely. 

■ This indicator does not address pesticide usage in 

non-agricultural areas. 

Data Sources

The data sources for this indicator are the Summary Report: 

1997 National Resources Inventory (Revised December 2000), 

U.S. Department of Agriculture, Natural Resources Conservation

Service, and the National Pesticide Use Database, National Center

for Food and Agricultural Policy, 1995. (See Appendix B, page 

B-21, for more information.)

Indicator Potential pesticide runoff from farm fields – Category 2 (continued)
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Indicator Risk of nitrogen export – Category 2 

3-34 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

Predictive risk models show higher nutrient concentrations in

watersheds dominated by agricultural and urban and suburban

land uses. Watersheds with mixed uses tend to have forested lands

that reduce concentrations of nutrients. Various field-based 

studies show a strong relationship between land cover and the

amount of nutrients exported from a watershed (e.g., measured in

the stream at the watershed outlet) (Beaulac and Reckhow, 1982).

Exports are typically measured as mass per unit area per unit time

(e.g., lbs/acre/year). Nitrogen exports tend to increase as agriculture and urban and suburban uses replace forest land. Several

additional factors affect the actual amount exported, however,

such as cropping management practices, the timing of rainfall versus cropping stage, density of impervious surfaces, and soil types. 

The risk classes described by this indicator are based solely on

proportions of agriculture, forest, and urban and suburban land

within a watershed derived from the NLCD. Nutrient export data

compiled from watersheds with homogenous land cover were used

in a Monte Carlo approach to simulate loads of nitrogen for

watersheds with mixed land cover. The model can be used to 

estimate annual load for any point in the distribution or for risk 

of exceeding user-defined thresholds. When used to estimate risk,

the model conceptually incorporates factors other than land cover

as mentioned above. 

What the Data Show

Exhibit 3-20 shows the risk of nitrogen export. Risk is expressed

as the number of times per 10,000 trials the nitrogen export

exceeded a threshold of 6.5 lbs/acre/year. The 6.5 threshold was

chosen because it represents the maximum value observed for

watersheds that were entirely forest. A risk value of 0.5 indicates a

1 out of 2 chance that a particular watershed would exceed the

risk threshold because of its mix of land cover (e.g., forest, agriculture, urban/suburban). The watersheds in Exhibit 3-20 are 

categorized into five classes based on risk. About 46 percent of

the watersheds are in the lowest risk class and 15 percent in the 

highest. The lowest risk watersheds make up most of the western

U.S., northern New England, northern Great Lakes, and southern

Appalachians. The highest risk classes are concentrated in the

midwestern grain belt. The eastern U.S. shows a mottling of high

and low risk classes among adjacent watersheds. 

Indicator Gaps and Limitations

The potential risk of nitrogen runoff calculated from the NLCD

data relies on various classifications and models that have inaccuracies that might affect results. To nationally monitor all watershed

variables that affect nutrient export is impossible. Therefore, the

data for this indicator are based on statistical simulation and the

well-documented relationship between land cover and nutrient

export to estimate the risk (or likelihood) of export exceeding a

certain threshold. The accuracy of the model is affected by the

accuracy of the classification of the cover types—forest, agriculture, and urban/suburban—which range from 80 percent to 90

percent in most cases. The accuracy also is affected by lack of

model input for other land cover classes that can occur within

watersheds, particularly in the western U.S. Model performance

has been evaluated in the mid-Atlantic region, and modeled

results generally agree with observed values. In the western U.S.,

shrubland and grassland cover share dominance with forest and

agriculture. For national application of the model, shrubland and

grassland classes were treated as forest because these land-cover

classes, like forest, lack strong anthropogenic inputs of nitrogen.

Further research to refine the empirical models for shrubland and

grassland cover classes would be useful.

Data Sources

The data source for this indicator is the National Land Cover

Data, Multi-Resolution Land Characteristics Consortium, 1992.

(See Appendix B, page B-22, for more information.)
Technical Document ■ EPA’s Draft Report on the Environment 2003

Indicator Risk of nitrogen export – Category 2 (continued)

Indicator Risk of phosphorus export – Category 2

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-35

Like nitrogen export, the same strong relationship exists

between land cover and phosphorus export. Risk is expressed

as the number of times out of 10,000 trials that the phosphorus export threshold of 0.74 lbs/acre/year was exceeded. The

0.74 threshold was chosen because it represents the maximum

value observed for watersheds that were entirely forest. The

model uses an identical approach to that just described in the

“risk of nitrogen export” indicator. 

What the Data Show

Exhibit 3-21 shows potential for phosphorus export at greater

than 0.74 pounds per acre per year. About 74 percent of the

watersheds are in the two lowest risk classes. These make up most

of the western U.S., as well as the eastern seaboard and the

Appalachians. Only 1 percent of the watersheds are in the highest

risk classes, and these are scattered throughout the midwestern

grain belt, but also in many of the nation’s major urban/suburban

Exhibit 3-20: Estimates of risk of nitrogen export by watershed, 1992

Risk Classes (#Obs.)

0.000 - 0.149

0.150 - 0.299

0.300 - 0.449

0.450 - 0.599

0.600 - 0.749

(max. = 0.696)

(326)

(1251)

(269)

(271)

(24)

Source: Wickham, J.D. et al., Land Cover as a Framework for Assessing Risk of Water Pollution. 2000.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-36 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

Indicator Risk of phosphorus export – Category 2 (continued)

areas. Many major urban/suburban areas exist at the intersection

of two watersheds, and the “urban” influence, which would make

the phosphorus risk higher, is spread over multiple watersheds.

This partially explains why some urban/suburban areas show lower

risk than others. Identification of higher phosphorus export risk in

urban/suburban areas differs somewhat from the spatial pattern

for nitrogen export risk, because the empirical data suggest that

urban/suburban areas present higher risk of phosphorus export

than nitrogen export.

Indicator Gaps and Limitations

The potential risk of phosphorus export is based on the aggregate

classes of forest, urban/suburban, and agriculture from the NLCD.

Accuracy of these classes ranges from 80 to 90 percent in most

cases. Model performance has been evaluated in the mid-Atlantic

region, and modeled results generally agree with observed values.

In the western U.S., shrubland and grassland cover share dominance with forest and agriculture. For national application of the

model, shrubland and grassland classes were treated as forest,

because these land-cover classes, like forest, lack strong anthropogenic inputs of phosphorus. Further research to refine the

empirical models for shrubland and grassland land-cover classes

would be useful.

Data Source

The data source for this indicator is the National Land Cover

Data, Multi-Resolution Land Characteristics Consortium, 1992.

(See Appendix B, page B-22, for more information.)

Exhibit 3-21: Estimates of risk of phosphorus export by watershed, 1992

Risk Classes (#Obs.)

0.000 - 0.123

0.124 - 0.247

0.248 - 0.371

0.372 - 0.495

0.496 - 0.619

(max. = 0.619)

(326)

(1251)

(269)

(271)

(24)

Source: Wickham, J.D. et al., Land Cover as a Framework for Assessing Risk of Water Pollution. 2000.
Technical Document ■ EPA’s Draft Report on the Environment 2003

3.2.5 What human health effects

are associated with pesticides,

fertilizers, and toxic substances?

Many pesticides pose some risk to humans and the environment

because they are designed to kill or otherwise adversely affect living

organisms. The degree to which individuals and populations are

exposed to pesticides varies greatly by geographic location and

demographics. Children may be more susceptible than adults to the

effects of chemicals, including pesticides. Certain populations may

be more at risk than others, depending, for example, on sources of

drinking water or direct exposure to pesticide application. 

Various pesticide surveillance systems exist that collect information

on pesticide-related injury and illness, but data are limited. One

example, the Toxic Exposure Surveillance System (TESS), contains

information from poison control centers around the country that

report occurrences of pesticide-related injury and illness. 

Other data collected from poison control centers showed that in

2000, more than 100,000 people were sufficiently concerned about

exposure to various types of pesticides to call their local Poison

Control Center. 

The TRI database tracks toxic chemicals because of the risks that these

chemicals pose to human health and ecological condition. Studies have

made accurate associations between isolated chemicals and their specific

health effects. For example, the pesticide atrazine has been shown to have

developmental and reproductive effects in animals and fish, depending on

the level of exposure (EPA, OPP, 2002). PBT chemicals such as mercury

and lead can cause acute or chronic health problems, even when people

are exposed to small quantities of the chemicals (See box “Persistant

Bioaccumulative Toxic Chemicals”) (EPA, October 1999). Though these

single chemical assessments are useful, a greater challenge lies in correlating the existence of chemicals that interact in the environment to the

health effects observed in a given population.

Fertilizers are often applied in greater quantities than crops can

absorb and end up in surface or ground water. Although fertilizers

may not be inherently harmful, they can be linked to human health

problems when excess nutrients cause algal blooms and

eutrophication in waterbodies. Drinking ground water contaminated

with runoff from some fertilizers can have severe or even fatal health

effects, especially in infants and children (e.g., blue baby syndrome)

(Amdur, et al, 1996).

Another emerging issue is the use of recycled industrial waste in

fertilizer. Depending on the material and how it is processed, the

presence of heavy metals such as lead or cadmium in fertilizers

produced with recycled waste can introduce contaminants to the

soil and increase the health risks associated with fertilizer use.

Many states have begun to test and require labeling for fertilizers

containing metals and hazardous waste.

No specific indicators have been identified at this time. There is

additional discussion of human health effects of chemical use in

Chapter 4, Human Health. 

Chapter 3 - Better Protected Land 3.2 Chemicals in the Landscape 3-37

Persistent Bioaccumulative Toxic Chemicals

Human exposure to PBT chemicals increases over time because

these chemicals persist and bioaccumulate in the environment.

Therefore, even small quantities of these chemicals are of

concern. In 1999, EPA lowered the TRI reporting threshold for 13

chemicals called persistent bioaccumulative toxic chemicals

(PBTs), including dioxins, mercury, lead, and polychlorinated

biphenyls (PCBs). Of the total 38 billion pounds of managed

toxic chemicals in 2000, PBTs comprised approximately 72

million pounds. Of the total 7.10 billion pounds of toxic

chemicals released to the environment, PBTs accounted for 12.1

million (less than 1 percent). The specific types of PBTs that

comprised the 12.1 million pounds were polycyclic aromatic

compounds (45 percent), mercury and mercury compounds 

(36 percent), PCBs (12 percent), pesticides (0.7 percent), and

other PBTs (7 percent)(EPA, OEI, 2002).
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-38 3.2 Chemicals in the Landscape Chapter 3 - Better Protected Land

3.2.6 What ecological effects are

associated with pesticides,

fertilizers, and toxic substances?

Nitrogen runoff from farmlands and animal feeding operations can

contribute to eutrophication of downstream waterbodies and sometimes impair the use of water for drinking water purposes. Nutrient

enrichment (nitrogen and phosphorus) is one of the leading causes

of water quality impairment in the nation’s rivers, lakes, and estuaries.

EPA reported to Congress in 1996 that 40 percent of rivers in the

U.S. were impaired due to nutrient enrichment; 51 percent of the

surveyed lakes and 57 percent of the surveyed estuaries were similarly adversely affected (EPA, OW, December 1997). Nutrients have

also been implicated in identification of the large hypoxic zone in the

Gulf of Mexico, hypoxia observed in several East Coast states, and

harmful algal bloom-induced fish kills and human health problems in

the coastal waters of several East Coast and Gulf states .

Just as the sources of nitrogen in watersheds vary, so do the effects

of exported nitrogen. While high levels of nitrogen might not affect

the watersheds from which the nutrient is exported, exports can

influence the condition of coastal estuaries and lakes. The effects

vary with such factors as water-column mixing, sunlight, temperature,

and the availability of other nutrients. 

No specific indicators have been identified at this time. Effects 

of chemical use on ecological condition are discussed more 

extensively in Chapter 2, Purer Water; and Chapter 5, 

Ecological Condition.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-39

3.3 Waste and

Contaminated Lands

Waste and contaminated lands are discussed in this section. Waste is

broadly defined as unwanted materials left over from manufacturing

processes or refuse from places of human or animal habitation.

Several waste categories and types are included within this broad

definition. In general, waste can be categorized as either hazardous

or non-hazardous. Hazardous wastes are the by-products of society

that can pose substantial or potential hazards to human health or

the environment when improperly managed. These wastes may

appear on special EPA lists and they possess at least one of the four

following characteristics: ignitability, corrosivity, reactivity, or toxicity.

Hazardous waste includes specific types of waste, such as toxic 

waste and radioactive waste. All other waste is considered to be 

non-hazardous (EPA, OEI, May 2002). 

Several specific kinds of waste consist of mixed hazardous and 

non-hazardous content. For instance, municipal solid waste (e.g.,

garbage) is largely non-hazardous but does typically contain some

household hazardous waste items such as solvents or batteries.

Other materials and waste types that can have mixed

hazardous/non-hazardous content include animal waste, by-products

of oil and gas production, materials from leaking underground 

storage tanks, and waste from coal combustion. 

Contaminated lands are lands that have been contaminated with 

hazardous materials and require remediation. Contaminated lands 

are not the same as lands used for waste management. In many

instances, lands used for waste management are not contaminated.

Similarly, often no waste is present on contaminated lands.

Contaminated lands can pose a direct risk if they expose people, 

animals, or plants to harmful materials or cause the contamination 

of air, soil, sediment, surface water, or ground water. 

Despite numerous waste-related data collection efforts at the state

and national levels, nationally consistent and comprehensive data on

the status, pressures, and effects of waste and contaminated lands

are limited. Various parties are responsible for tracking types and

amounts of waste and contaminated sites. National-level data on

waste and contaminated land tend to be collected to satisfy the

requirements of specific federal regulations. For example, EPA's

Resource Conservation and Recovery Act Information System

(RCRAInfo) contains data on RCRA hazardous waste and EPA's

Comprehensive Environmental Response, Compensation, and Liability

Information System (CERCLIS) contains some data on contaminated

sites, including Superfund sites. 

Few national data sets exist for the waste types that are not federally

regulated, such as non-hazardous industrial waste. Although a significant amount of waste information and some site contamination

information is collected and tracked at the local or state government

levels, these data are seldom aggregated nationally. Also, most of the

available data describe waste in terms of weight, rather than volume.

The weight data alone do not address the extent of the waste situation in the U.S. Similarly, national information about contaminated

lands tends to focus on number of sites and types of contamination,

rather than the extent of land contaminated. Finally, there is a lack of

national data that track the effects of waste and contaminated land

on human health and ecological condition. 

While major improvements have been made in managing the nation's

waste and cleaning up contaminated sites, more work remains.

National, state, tribal, and local waste programs and policies aim to

prevent pollution by reducing the generation of wastes at their

source and by emphasizing prevention over management and disposal. Preventing pollution before it is generated and poses harm is

often less costly than cleanup and remediation. Source reduction

and recycling programs often can increase resource and energy efficiencies, reduce pressures on the environment, and extend the life

span of disposal facilities.

The following questions and discussion of indicators provide an

overview of what is known about waste generation and management

and about contaminated lands in the U.S. Trends and conditions on

a national basis are described to the extent that data are available.

The five questions considered in this section are:

■ How much and what types of waste are generated and managed?

■ What is the extent of land used for waste management?

■ What is the extent of contaminated land?

■ What human health effects are associated with waste management

and contaminated lands?

■ What ecological effects are associated with waste management

and contaminated lands?

EPA is the primary source of data for this section, providing

municipal solid waste data on generation, management, recovery,

and disposal; data on RCRA hazardous waste and corrective

action sites from the RCRAInfo database; and data on the number

and location of contaminated sites that are on the Superfund

National Priorities List (NPL) from CERCLIS. The U.S. Department

of Energy's (DOE) Central Internet Database provides information

on the types and quantities of radioactive waste generated and 

in storage. 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-40 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

There are numerous types of waste, but only three types are tracked

with any consistency on a national basis. The three that are

described as indicators on the following pages include municipal

solid waste (MSW), hazardous waste (as defined by RCRA), and

radioactive waste. The other types of waste range from materials

generated during mining and agricultural activities to wastes from

manufacturing and construction. Current national data are not 

available on these other types of waste. Exhibit 3-22 summarizes 

the types of waste.

Type Description

Medical Waste 

Municipal 

Solid Waste 

(Indicator)

Extraction 

Wastes 

Industrial 

Non-Hazardous 

Waste 

Exhibit 3-22: Types of Waste

Municipal solid waste (MSW) is the waste discarded by households, hotels/motels, and commercial, institutional, and industrial sources. MSW 

typically consists of everyday items such as product packaging, grass clippings, furniture, clothing, bottles, food scraps, newspapers, appliances, 

paint, and batteries. It does not include wastewater. In 2000, 232 million tons of MSW were generated. (EPA, OSWER, June 2002)

The term “RCRA hazardous waste” applies to certain types of hazardous wastes that appear on EPA’s regulatory listing (RCRA) or that exhibit 

the specific characteristics of ignitability, corrosiveness, reactivity, or toxicity. More than 40 million tons of RCRA hazardous waste were 

generated in 1999. (EPA, OSWER, June 2001)

RCRA Hazardous 

Waste 

(Indicator) 

Radioactive waste is the garbage, refuse, sludge, and other discarded material, including solid, liquid, semi-solid, or contained gaseous material 

that must be managed for its radioactive content (DOE Order 435.1 Issued July 1999). The technical names for the types of waste that are 

considered “radioactive waste” for this report are high-level waste, spent nuclear fuel, transuranic waste, low-level waste, mixed low-level waste, 

and contaminated media. Data on the amounts of these waste types are provided in the radioactive waste discussion. (See Appendix D for 

definitions of these terms). 

Radioactive 

Waste 

(Indicator) 

Extraction activities such as mining and mineral processing are large contributors to the total amount of waste generated and land contaminated 

in the U.S. EPA estimates that 5 billion tons of mining wastes were generated in 1988 (EPA, OSWER, October 1988).

Industrial non-hazardous waste is process waste associated with electric power generation and manufacturing of materials such as pulp and paper, 

iron and steel, glass, and concrete. This waste usually is not classified as either municipal solid waste or RCRA hazardous waste by federal or state 

laws. State, tribal, and some local governments have regulatory programs to manage industrial waste. EPA estimated that 7.6 billion tons of 

industrial non-hazardous wastes were generated in 1988. (EPA, OSWER, October 1988)

Most household products that contain corrosive, toxic, ignitable, or reactive ingredients are considered household hazardous waste. Examples 

include most paints, stains, varnishes, solvents, and household pesticides. Special disposal of these materials is necessary to protect human health 

and the environment, but some amount of this type of waste is improperly disposed of by pouring the waste down the drain, on the ground, in 

storm sewers, or by discarding the waste with other household waste as part of municipal solid waste. EPA estimates that Americans generate 1.6 

million tons of household hazardous waste per year, with the average home accumulating up to 100 pounds annually. (EPA, OSWER, October 

2002)

Household 

Hazardous 

Waste 

Agricultural solid waste is waste generated by rearing animals and producing and harvesting crops or trees. Animal waste, a large component of 

agricultural waste, includes waste from livestock, dairy, milk, and other animal-related agricultural and farming practices. Some of this waste is 

generated at sites called Confined Animal Feeding Operations (CAFOs). The waste associated with CAFOs results from congregating animals, 

feed, manure, dead animals, and production operations on a small land area. Animal waste and wastewater can enter water bodies from spills or 

breaks of waste storage structures (due to accidents or excessive rain) and non-agricultural application of manure to crop land (EPA, OW, 

November 2001; EPA, OW, June 2002). National estimates are not available.

Agricultural 

Waste 

Construction and demolition debris is waste generated during construction, renovation, and demolition projects. This type of waste generally 

consists of materials such as wood, concrete, steel, brick, and gypsum. (The MSW data in this report do not include construction and demolition 

debris, even though sometimes construction and demolition debris are considered MSW.) National estimates are not available.

Construction 

and Demolition 

Debris

Medical waste is any solid waste generated during the diagnosis, treatment, or immunization of human beings or animals, in research, production, 

or testing. National estimates are not available.

Oil and gas production wastes are the drilling fluids, produced waters, and other wastes associated with the exploration, development, and 

production of crude oil or natural gas that are conditionally exempted from regulation as hazardous wastes. National estimates are not available.

Oil and Gas 

Waste 

Sludge Sludge is the solid, semisolid, or liquid waste generated from municipal, commercial, or industrial wastewater. National estimates are not available.

Indicators 

Quantity of municipal solid waste (MSW) generated and managed

Quantity of RCRA hazardous waste generated and managed

Quantity of radioactive waste generated and in inventory

3.3.1 How much and what types of

waste are generated and managed?
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-41

As noted in Exhibit 3-22, municipal solid waste (MSW) is the

waste discarded by households and by commercial, institutional, and industrial operations. This type of waste is familiar to

most Americans because they are specifically responsible for 

its generation. MSW typically consists of everyday items such

as product packaging, grass clippings, furniture, clothing, 

bottles, food scraps, newspapers, appliances, paint, and 

batteries. It does not include wastewater.

What the Data Show

In 2000, Americans generated 232 million tons of MSW (Exhibit

3-23). This total amount, which does not take into account MSW

that was ultimately recycled or composted, equated to approximately 4.5 pounds of waste per person per day. Paper and 

paperboard products accounted for the largest component of

MSW generated (37 percent), and yard trimmings constituted the 

second-largest material component (12 percent). Glass, metals,

plastics, wood, and food scraps each constituted 5 to 11 percent

of the total. Rubber, leather, and textiles combined made up about

seven percent of MSW, while other miscellaneous wastes made up

approximately 3 percent (EPA, OSWER, June 2002).

The total amount of MSW generated increased nearly 160 percent

between 1960 and 2000 (Exhibit 3-24). For comparison purposes, during that same time frame, the U.S. population increased by

56 percent, gross national product increased nearly 300 percent,

and per capita generation of waste rose more than 70 percent

(DOC, BEA, 2002; EPA, OSWER, June 2002). The amount of

MSW generated per capita generally stabilized between 1990 and

2000, increasing less than one percent.

The data on the total amount of MSW generated do not factor in

source reduction and waste prevention or materials recovery

(recycling and composting), which are also important contributors

to the overall municipal waste picture. Source reduction and waste

prevention include the design, manufacture, purchase, or reuse of

materials to reduce their amount or toxicity or lengthen their life

before they enter the MSW system. Between 1992 and 2000,

source reduction in the U.S. prevented more than 55 million tons

of MSW from entering the waste stream (EPA, OSWER, June

2002) (Exhibit 3-25).

Indicator Quantity of municipal solid waste (MSW) generated and managed – Category 2

Exhibit 3-23: Total municipal solid waste generated, 2000

Total (before recycling and composting) = 232 million tons

Wood: 5.5% Other: 3.2%

Glass: 5.5%

Rubber, Leather &

Textiles: 6.7%

Metals: 7.8%

Plastics: 10.7%

Food Waste: 11.2% Yard Waste: 12%

Paper: 37.4%

Source: EPA, Office of Solid Waste and Emergency Response. Municipal Solid Waste in 

the United States: 2000 Facts and Figures. June 2002.

Source: EPA, Office of Solid Waste and Emergency Response. Municipal Solid Waste 

in the United States: 2000 Facts and Figures. June 2002.

Exhibit 3-24: Municipal solid waste generation rates, 

1960–2000

Tons of Waste (Millions)/Population (Millions)

(before recycling and composting)

0

50

100

150

200

250

300

1960 1970 1980 1990 1995 2000

0

2

4

6

8

10

12

Per Capita Generation (pounds/day)

Tons of Waste Generated (millions) 

Population (millions)

Per-capita Generation (pounds/day)
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-42 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

Materials recovery (recycling and composting) has also reduced

the total amount of MSW being discarded. In 2000, approximately 30 percent (70 million tons) of the MSW generated was recovered and thereby diverted from landfills and incinerators. Between

1960 and 2000, the total amount of MSW recovered has significantly increased from 5.6 million tons to 69.9 million tons, more

than a 1,100 percent increase. During this time period, the

amount recovered on a per capita basis increased from 0.17

pounds per person per day to 1.35 pounds per person per day—

an 8-fold increase (EPA, OSWER, June 2002). The percentage of

MSW disposed of in landfills has dropped from 83.2 percent of

the amount generated in 1986 to 55.3 percent of the amount

generated in 2000 (Exhibit 3-26). Combustion (incineration) is

also used to reduce waste volume prior to disposal in a landbased waste management facility. Approximately 33.7 million tons

(14.5 percent) of MSW were combusted in 2000. Of this amount,

approximately 2.3 million tons were combusted with energy 

recovery—also known as waste-to-energy combustion 

(EPA, OSWER, June 2002).

Indicator Gaps and Limitations

Limitations for this indicator include the following:

■ The MSW data do not include construction and demolition

debris, municipal waste water treatment sludge, automobile

bodies, combustion ash, and non-hazardous industrial wastes

that may go to a municipal waste landfill. The data (including

the generation, recycling, and recovery data) are generated

using the materials flow method, which does not include 

these materials, even though some of these materials 

(namely construction and demolition debris) are typically

counted as MSW. 

■ Residues associated with other items in MSW (usually

containers) are not accounted for in the data. 

■ The percentage of total waste that MSW represents is unknown. 

■ The indicator does not necessarily measure the effects of

changes in consumer or disposal trends.

Data Source

The data source for this indicator is Municipal Solid Waste Data,

EPA, Office of Solid Waste and Emergency Response, 1990-2000.

(See Appendix B, page B-22, for more information.)

Indicator Quantity of municipal solid waste (MSW) generated and managed – Category 2 (continued)

Exhibit 3-25: Source reduction of municipal 

solid waste, 1992-2000

Millions of tons

0

10

20

30

40

50

60

1992 1993 1994 1995 1996 1997 1998 1999 2000

Source: EPA. Office of Solid Waste and Emergency Response. Municipal Solid Waste 

in the United States: 2000 Facts and Figures. June 2002.

Data

Not

0.6 Available

8.0

21.4

31.0 31.8

37.3

42.8

55.1

Other MSW

Containers & Packaging

Nondurable Goods

Durable Goods

Total Amount

Materials Categories:

Exhibit 3-26: Municipal solid waste management, 

1960–2000

Millions of tons

* Composting of yard trimmings and food wastes. Does not include mixed MSW 

composting or backyard composting. 

Source: EPA, Office of Solid Waste and Emergency Response. Municipal Solid Waste 

in the United States: 2000 Facts and Figures. June 2002.

0

50

100

150

200

250

1960 1965 1970 1975 1980 1985 1990 1995 2000

Recovery for Composting*

Recovery for Recycling

Combustion

Landfill

(2000 total = 232 million tons)
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-43

Businesses that generate a substantial amount of RCRA hazardous

waste as part of their regular activities are called "large quantity

generators" or LQGs. ("Substantial" is defined as more than

2,200 pounds per month.) National data on "small quantity 

generators" (SQGs) and "conditionally-exempt small quantity 

generators" (CESQGs) are not available. Estimates indicate, however, that the amount of RCRA hazardous waste that SQGs and

CESQGs generate is relatively small (EPA, OSWER, June 2000).

What the Data Show

In 1999, EPA estimated that more than 20,000 LQGs collectively

generated 40 million tons of RCRA hazardous waste (EPA,

OSWER, June 2001). The number reflects between 95 and 99

percent of the total amount of RCRA hazardous waste generated.

The exact total amount of RCRA hazardous waste generated by

LQGs, SQGs, and CESQGs combined is not known, but the contributions of SQGs and CESQGs are estimated to be between 0.4

million tons and 2.1 million tons (or 1 to 5 percent) of the total

amount of RCRA hazardous waste (EPA, OSWER, June 2000). 

LQGs within EPA Region 6 (see Exhibit 1-12 for Regional delineation) generated more than half of all RCRA hazardous waste in

1999 (Exhibit 3-27). Less than 9 percent of the LQGs nationwide are located in Region 6, but 15 of the 22 largest national

generators (by quantity generated) are there. Of the large

Region 6 generators, 13 manufacture chemicals, petrochemicals,

minerals, and metal; and two manage chemical wastes.

Generation in Regions 4 and 5 accounted for 18 percent and 

13 percent of the national total, respectively, and all other

Regions combined accounted for the remaining 17 percent 

(EPA, OSWER, June 2001). 

Assessing trends in hazardous waste is difficult because the data

collected over the last several years have changed. For example,

the exclusion of wastewater from the 1999 totals makes a comparison of the 1999 data with previous data (which included wastewater) misleading. What is known, however, is that the amount of

a specific set of toxic chemicals (Waste Minimization Priority

Chemicals, or WMPC) found in hazardous waste is declining. 

(See the discussion of WMPC in the "Chemicals in the Landscape"

section of this chapter.)

RCRA hazardous waste management is conducted at RCRA treatment, storage, and disposal facilities (TSDs) (see indicator in the

following pages on Land Used for Waste Management). In 1999,

TSDs managed 26.3 million tons of hazardous waste through

treatment, storage, or disposal. 

The (non-wastewater) management methods used in 1999 

were as follows:

■ Land disposal (69 percent): Includes deepwell/underground

injection (16.0 million tons), landfill (1.4 million tons), 

surface impoundment (0.7 million tons), and land

treatment/application/farming (30 thousand tons). Prior to

land disposal, hazardous waste is treated to reduce toxicity 

and to prevent exposure of people and the environment to

harmful constituents.

■ Thermal treatment (11 percent): Includes energy recovery (1.5

million tons) and incineration (1.5 million tons). 

■ Recovery operations (10 percent): Includes fuel blending (1.1

million tons), metals recovery for reuse (0.72 million tons),

solvents recovery (368 thousand tons), and other recovery

(152 thousand tons). 

■ Other (11 percent): Includes other disposal (1.4 million tons),

stabilization (1.3 million tons), sludge treatment (48 thousand

tons) (EPA, OSWER, June 2001). 

Indicator Quantity of RCRA hazardous waste generated and managed – Category 2

Exhibit 3-27: Amount of Resource 

Conservation and Recovery Act (RCRA) 

hazardous waste generated in EPA regions, 1999

(Tons)

CBI* Data: <1% (1,066) Region 10: 3% (1,025,614)

Region 9: 1% (480,858)

Region 8: <1% (162,099)

Region 7: 5% 

(1,842,853)

Region 6: 52%

(20,901,778)

Region 5: 18%

(7,137,374)

Region 4: 13%

(5,094,526)

Region 3: 2% (739,262)

Region 2: 3% (1,298,602)

Region 1: 3% (1,342,020)

* Confidential Business Information not shown in pie chart

Source: EPA, Office of Solid Waste and Emergency Response. The National Biennial 

RCRA Hazardous Waste Report. June 2001. 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Indicator Gaps and Limitations 

While RCRAInfo is a reliable source of data about much of the

hazardous waste generated throughout the U.S., it does not provide information about all hazardous waste generated nationally.

RCRAInfo includes data on amounts and types of hazardous waste

generated nationally by large quantity generators only. Data about

amounts and types of hazardous waste generated by RCRA SQGs

and CESQGs are not collected. Similarly, data on waste that does

not fit the RCRA definition of "hazardous" are not available. Some

states regulate and collect data on wastes they designate as 

"hazardous" that are not tracked by EPA, but these data are not

aggregated nationally. 

Data Source

The data source for this indicator is 1999 RCRAInfo data, 

from EPA, Office of Solid Waste and Emergency Response. 

(See Appendix B, page B-22, for more information.)

Indicator Quantity of RCRA hazardous waste generated and managed – Category 2 (continued)

Indicator Quantity of radioactive waste generated and in inventory – Category 2

3-44 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

The manufacture and production of nuclear materials and

weapons requires activities that can generate large amounts of

radioactive waste. Over the past few decades, the production of

nuclear weapons has largely been suspended. The largest quantities of radioactive waste generated today (when measured by 

volume) result from the cleanup of contaminated sites. 

What the Data Show

A significant amount of the radioactive waste in existence 

today will remain radioactive for many years—in some cases

thousands of years. When measured by volume, the radioactive

waste that is still being generated reflects only a small percentage (<10 percent) of the total amount of waste that is either in

storage (inventory) or disposed of already. When measured by

radioactivity, the amount of radioactive waste in inventory far

exceeds the radioactivity of newly-generated radioactive waste

(U.S. DOE, April 2001). Exhibit 3-28 provides summary data

on the total amount of radioactive waste generated and in

inventory (storage) at the end of fiscal year (FY) 2000.

Over time, the amount of radioactive waste generated has fluctuated primarily due to the progress of site cleanup operations.

Trend data on generation rates over the past several years are

not available. According to the DOE, however, the amount of

waste generated between late 1997 and late 2000 remained

fairly constant, while the amount in inventory increased in proportion to the amount generated (DOE, 2002). Although some

radioactive waste is still being disposed of (e.g., small amounts

of transuranic waste are being disposed of at the Waste

Isolation Pilot Plant in New Mexico), most of the highly radioactive waste types remain in storage until they can be placed in safe

long-term disposal facilities. 

The amount of radioactive waste being generated and stored is

expected to drop over the next few decades as cleanup operations

are completed and waste currently in storage is disposed of.

Depending on the radioactive decay rate, the disposed-of waste

will remain radioactive for time periods ranging from days to 

thousands of years.

Indicator Gaps and Limitations

The radioactive waste data in this report do not account for all

radioactive materials in the U.S. The term "radioactive waste"

applies to any garbage, refuse, sludge, and other discarded 

material that must be managed for its radioactive content (DOE

Order 435.1, issued July 1999). Other radioactive materials are

used for defense, energy production, and other purposes, but

these materials are not considered "waste." Further, DOE is not

responsible for some additional radioactive waste (quantity

unknown). Data on these wastes are not included in this report. 

Data Source

The data source for this indicator is radioactive waste data, from

U.S. Department of Energy’s Central Internet Database, 2000.

(See Appendix B, page B-23, for more information.)
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-45

Indicator Quantity of radioactive waste generated and in inventory – Category 2 (continued)

 Waste Type Generated Inventory (Storage) Units

Exhibit 3-28: Total amount of radioactive waste* generated in fiscal year 2000 as reported by Department of Energy 

Vitrified High-Level Waste

High-Level Waste

Low-Level Waste

Mixed Low-Level Waste

Ex-Situ Contaminated Media

Transuranic Waste

Spent Nuclear Fuel

n/a

14,166

38,911

10,834

559,249

1,621

0.85

1,201

353,501

101,256

44,588

63,570

111,226

2,467

Canisters

Volume 

(cubic meters)

Mass (metric tons 

of heavy metal)

Source: U.S. Department of Energy, Office of Environmental Management, Central Internet Database. 2002.

(January 2003; http://cid.em.doe.gov).

* For the purposes of this report, all of the materials in this table are considered radioactive waste. 

Most types of waste are disposed of in land-based waste management units such as MSW landfills and surface impoundments. Prior

to the 1970s, waste disposed of on the land was typically dumped 

in open pits, and waste was seldom treated to reduce its toxicity

prior to disposal (EPA, OSWER, June 2002). Early land disposal units

that still pose threats to human health and the environment are 

considered to be contaminated lands subject to federal or state

cleanup efforts and are discussed in the next section. Today, most of

the hazardous and MSW land disposal units are subject to federal or

state requirements for landfill, surface impoundment, or pile design

and management. National data for these disposal units is described

in the indicators following. 

Many other sites are used for waste management in addition to the

MSW landfills and RCRA hazardous waste facilities just mentioned.

Although comprehensive data sets are not available to assess the

number of additional sites used for waste management, various 

EPA estimates show that there were approximately 18,000 

non-hazardous industrial waste surface impoundments in 2000,

more than 2,700 non-hazardous industrial waste landfills in 1985,

and more than 5,300 non-hazardous industrial waste piles in 1985 

(EPA, OSWER, March 2001). These numbers do not include other

waste management sites, such as those used to collect and manage

(but not dispose of) waste (e.g., recycling centers, household 

hazardous waste collection centers), waste transfer stations, sites

that store discarded automobile and industrial equipment, and 

non-regulated landfills.

The two indicators identified for this question address the number

and location of MSW landfills and RCRA facilities.

Indicators 

Number and location of municipal solid waste (MSW) landfills 

Number and location of RCRA hazardous waste management facilities

3.3.2 What is the extent of land

used for waste management?
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-46 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

Municipal solid waste landfills are the most commonly known places

of waste disposal. Yet this does not mean that there are good data

to track them. The data presented in support of this indicator are

estimates compiled by a national journal. No federal agency specifically compiles information nationally on these landfills. 

What the Data Show

In 2000, approximately 128 million tons (55 percent) of the

nation's 232 million tons of MSW were disposed of in the nation's

2,216 municipal waste landfills (EPA, OSWER, June 2002).

Between 1989 and 2000, the number of municipal landfills in the

U.S. decreased substantially (down from 8,000). Over the same

period, the capacity of all landfills remained fairly constant

because newer landfills typically have larger capacities. In 2000,

these landfills were geographically distributed as follows: 154 (8

percent) in the Northeast, 699 (35 percent) in the Southeast,

459 (23 percent) in the Midwest, and 655 (33 percent) in the

West (Goldstein, 2000). 

Indicator Gaps and Limitations

MSW data are voluntarily submitted to BioCycle Journal and are

not reviewed for quality or consistency. The data exclude landfills in Alaska and Hawaii and do not indicate the capacity or

volume of landfills, or in general, a means to estimate extent of

lands used for MSW management. For example, the fact that

there are fewer landfills does not mean that less land is used for

managing wastes because newer landfills are typically larger than

their predecessors. The information is also limited by the fact

that other lands are also used for waste management, such as

for recycling facilities and waste transfer stations, but are not

included in the indicator data. The data also do not reflect upon

the status or effectiveness of landfill management or the extent

to which contamination of nearby lands does or does not occur. 

Data Source

The data source for this indicator is BioCycle Journal municipal

landfill data 1990-2000. (See Appendix B, page B-23, for more

information.)

Indicator Number and location of municipal solid waste (MSW) landfills – Category 2

Indicator Number and location of RCRA hazardous waste management facilities – Category 2

The RCRA Treatment, Storage, and Disposal (TSD) facilities used to

manage the more than 26 million tons of annually generated hazardous waste are tracked closely by EPA. The data, however, are

tracked and reported in terms of number of facilities and volumes of

waste managed, not the acres of land used for management. 

What the Data Show

Nearly 70 percent of the RCRA hazardous waste (not including

wastewater) generated in 1999 was disposed of at one of the

nation's 1,575 RCRA TSDs. Of the 1,575 facilities, 1,049 were

storage-only facilities. The remaining facilities perform one or

more of the following management methods, which include recovery operations (the percentages reflect the percentage of total

facilities that conduct each management method): metals recovery

(16.8 percent), solvents recovery (21.1 percent), other recovery

(8.8 percent), incineration (28.4 percent), energy recovery 

(18.9 percent), fuel blending (19.8 percent), sludge treatment

(3.0 percent), stabilization (16.0 percent), land treatment/application/farming (1.3 percent), landfill (11.4 percent), surface

impoundment (0.4 percent), deepwell/underground injection 

(8.8 percent), or other disposal methods (7.4 percent). 

TSD facilities in five states accounted for approximately 65 percent of the national management total. From another perspective,

over 80 percent of the TSD facilities are located in EPA Regions 

4 (19.6 percent), Region 5 (16.9 percent), and Region 6 

(43.7 percent) (EPA, OSWER, June 2001). 

Indicator Gaps and Limitations

Some hazardous waste management information that is collected

by states is not included in the provided totals because it is not

compiled nationally. Further, data on actual extent of land used for

waste management are not collected, reported, or aggregated.

Basic data on the number of sites or facilities used for waste 

management do not answer the extent question. 

Data Source

The data source for this indicator is 1999 RCRAInfo data from EPA

Office of Solid Waste and Emergency Response. (See Appendix B,

page B-23, for more information.) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-47

Contaminated lands range from sites where underground storage

tanks have failed to areas where accidental spills have occurred to

legacy sites where poor site management resulted in the contamination of soil, sediment, and ground water. Sites are still being 

discovered and national data do not currently exist to describe the

full extent of contaminated lands. Additionally, sites are continually

being cleaned up by a variety of programs, although these sites are

not always immediately removed from the tracking lists maintained

by the cleanup programs (e.g., Superfund NPL). 

Two indicators are described. One addresses Superfund (NPL) sites

and the other RCRA Corrective Action sites. They represent the

limited data available for a national view of contaminated lands.

Both indicators are based on data collected to track cleanup

efforts and list numbers of sites, but neither specifically delineate

the extent or total area of land contamination. Besides these two

indicators that track specific programs, there are several other

types of contaminated lands for which national data are limited 

or are not available. In some cases, states collect and maintain

accurate data inventories, but these state-specific data sets are 

not compiled nationally. Exhibit 3-29 summarizes the types of

lands that are or might be considered contaminated. 

Type Description

Superfund 

National Priorities 

List Sites 

(Indicator)

Accidental 

Spill Sites

Exhibit 3-29: Types of contaminated lands 

RCRA 

Corrective 

Action Sites 

(Indicator)

Leaking 

Underground 

Storage 

Tanks

Congress established the Superfund Program in 1980 to clean up abandoned hazardous waste sites throughout the U.S. The 

most seriously contaminated sites are on the NPL. As of October 2002, there were 1,498 sites on the NPL (EPA, SERP, 

October 2002).

EPA and authorized states have identified 1,714 hazardous waste management facilities that are the most seriously 

contaminated and may pose significant threats to humans or the environment (EPA, OSWER, October, 2002). Some RCRA 

Corrective Action sites are also identified by the Superfund Program as NPL sites. 

Each year, thousands of oil and chemical spills occur on land and in water. Oil and gas materials that have spilled include 

drilling fluids, produced waters, and other wastes associated with the exploration, development, and production of crude oil 

or natural gas. Accurate national spill data are not available. 

EPA regulates many categories of underground storage tanks (USTs), often containing petroleum or hazardous substances. 

These exist at many sites, such as gas stations, convenience stores, and bus depots. USTs that have failed due to faulty 

materials, installation, operating procedures, or maintenance systems are categorized as leaking underground storage tanks 

(LUSTs). LUSTs can contaminate soil, ground water, and sometimes drinking water. Vapors from UST releases can lead to 

explosions and other hazardous situations if those vapors migrate to a confined area such as a basement. LUSTs are the most 

common source of ground water contamination (EPA, OW, 2000), and petroleum is the most common ground water 

contaminant (EPA, OW, 1996). According to EPA's corrective action reports, in 1996 there were 1,064,478 active tanks 

located at approximately 400,000 facilities. In 2002, there were 697,966 active tanks (a 34 percent decrease) and 

1,525,402 closed tanks ( a 42 percent increase). As of the fall of 2002, 427, 307 UST releases (LUSTs) were confirmed. 

(EPA, OSWER, December 2002).

Indicators 

Number and location of superfund national priorities list (NPL) sites

Number and location of RCRA corrective action sites

3.3.3 What is the extent of

contaminated lands?
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-48 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

Type Description

Land 

Contaminated 

with Radioactive 

and Other 

Hazardous 

Materials

Poorly Designed 

or Poorly 

Managed Waste 

Management 

Sites 

Illegal 

Dumping 

Sites

Exhibit 3-29: Types of contaminated lands (continued) 

Brownfields

Some

Military 

Bases

Abandoned

Mine Lands

Approximately 0.54 million acres of land spanning 129 sites in over 30 states are contaminated with radioactive and other 

hazardous materials as a result of activities associated with nuclear weapons production and research. Although DOE is the 

landlord at most of these sites, other parties, including other federal agencies, private parties, and one public university, also 

have legal responsibilities over these lands (DOE, January 2001).

Brownfields are real property, the expansion, redevelopment or reuse of which may be complicated by the presence or 

potential presence of a hazardous substance, pollutant, or contaminant (Small Business Liability Relief and Brownfields 

Revitalization Act, 2002). Brownfields are often found in and around economically depressed neighborhoods. As brownfields 

are cleaned and redeveloped, surrounding communities benefit from a reduction of health and environmental risks, more 

functional space, and improved economic conditions. A complete inventory of brownfields does not exist. According to the 

General Accounting Office (1987), there are approximately 450,000 brownfields nationwide (General Accounting Office, 

1987). The EPA's national brownfield tracking system includes a large volume of data on brownfields across the nation, but 

does not track all of them. EPA's Brownfield Assessment Pilot Program includes data collected from over 400 pilot 

communities (EPA, OSWER, May 2002).

Some (exact number or percentage unknown) military bases are contaminated as a result of military activities. A national 

assessment of land contaminated at military bases has not been conducted; however, under the Base Realignment and 

Closure (BRAC) laws, closed military bases undergo site investigation processes to determine extent of possible 

contamination and the need for site cleanup. Currently, 204 military installations that have been closed or realigned are 

undergoing environmental cleanup. These installations collectively occupy over 400,000 acres, though not all of this land is 

contaminated. Thirty-six of these installations are on the Superfund NPL list, and, of these, 32 are being cleaned up under 

the Fast Track program to make them available for other uses as quickly as possible (DOD, 2001).

Prior to the 1970s, untreated waste was typically placed in open pits or directly onto the land. Some of these early waste 

management sites are still contaminated. In other cases, improper management of facilities (that were typically used for 

other purposes such as manufacturing) resulted in site contamination. Federal and state cleanup efforts are now addressing 

those early land disposal units and poorly-managed sites that are still contaminated. 

Also known as "open dumping" or "midnight dumping," illegal dumping of such materials as construction waste, abandoned 

automobiles, appliances, household waste, and medical waste raises concerns for safety, property values, and quality of life. 

While a majority of illegally dumped waste is not hazardous, some of it is, creating contaminated lands. 

Abandoned mine lands are sites that have historically been mined and have not been properly cleaned up. These abandoned 

or inactive mine sites may include disturbances or features ranging from exploration holes and trenches to full-blown, largescale mine openings, pits, waste dumps, and processing facilities. The Department of the Interior's (DOI) Bureau of Land 

Management (BLM) is presently aware of approximately 10,200 abandoned hardrock mines located within the roughly 264 

million acres under its jurisdiction. Various government and private organizations have made estimates over the years about 

the total number of abandoned and inactive mines in the U.S., including estimates for the percent land management 

agencies, and state and privately-owned lands. Those estimates range from about 80,000 to hundreds of thousands of small 

to medium-sized sites. The BLM is attempting to identify, prioritize, and take appropriate actions on those historic mine sites

that pose safety risks to the public or present serious threats to the environment (DOI, BLM, 2003).
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-49

Congress established the Superfund Program in 1980 to clean up

abandoned hazardous waste sites throughout the U.S. The

Superfund Program tracks and investigates thousands of potentially contaminated sites to determine whether they are indeed

contaminated and require cleanup. Some sites are not contaminated, whereas others are seriously contaminated and require either

extensive, long-term cleanup action and/or immediate action to

protect human health and the environment. The most seriously

contaminated sites are proposed for placement on the NPL.

"Proposed" NPL sites that meet the qualifications for cleanup

under the Superfund Program become "final" NPL sites. Sites are

considered for deletion from the NPL when all cleanup goals are

met and there is no longer reason for federal action. 

What the Data Show

As of October 1, 2002, there were 1,498 sites that were either

final (1,233) or deleted (265). Of the 1,498 sites, 846 have

completed all necessary cleanup construction. A construction

complete site is a former toxic waste site where physical construction of all cleanup actions are complete, all immediate threats have

been addressed, and all long-term threats are under control. An

additional 62 sites were proposed in 2002 (Exhibit 3-30). The

total number of NPL sites (including proposed) grew from 1,236

in 1990 to 1,560 in 2002. During this time period, the number

of sites that have been cleaned up and have been transferred from

"final" to "deleted" status have increased nearly 10-fold, from 29

in 1990 to 265 in 2002. In 2002, over 56 percent of the final

and deleted sites were construction complete, compared to only

four percent of the sites in 1990 (EPA, SERP, February 2003).

Indicator Gaps and Limitations 

The NPL sites are tracked in CERCLIS. This database contains

information on hazardous waste sites across the nation and U.S.

territories including location, status, contaminants, and actions

taken from 1983 to the present. The number of NPL sites provides

a general indicator of contaminated lands, but these numbers do

not translate directly to the extent of contaminated land. The NPL

data cannot easily be used to clarify how many lands are contaminated because the NPL sites are divided into administrative

groups (i.e., proposed, final, and deleted) that do not clearly

describe whether the sites are currently contaminated.

Additionally, there are many contaminated sites in CERCLIS that

are not listed on the NPL, some contaminated sites are not in

CERCLIS (e.g., are known only by local and state programs), and

not all of the sites in CERCLIS are contaminated.

Data Source

The data source for this indicator is Comprehensive Environmental

Response Compensation, and Liability Information System 

(CERCLIS) data, EPA Superfund Emergency Response Program,

1983-2002. (See Appendix B, page B-24, for more information.)

Indicator Number and location of Superfund National Priorities List (NPL) sites - Category 2 

Note: "Construction Complete" sites include most "Deleted" sites and some "Final" sites. 

Source: EPA, Office of Solid Waste and Emergency Response. National Priorities List Site Totals by Status and Milestone. March 26, 2003. (April 3, 2003; 

http://www.epa.gov/superfund/sites/query/queryhtm/npltotal.htm) and Number of NPL Site Actions and Milestones by Fiscal Year. March 26, 2003. (April 3, 2003; 

http://www.epa.gov/superfund/sites/query/queryhtm/nplfy/htm). 

Exhibit 3-30. Superfund National Priorities List (NPL) site totals by status and 

Number of sites

0

300

600

900

1200

1500

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Deleted Sites

Final Sites

Proposed Sites

Construction Complete
3-50 3.3 Waste and Contaminated Lands Chapter 3 - Better Protected Land

Congress established the RCRA Corrective Action Program in

1984 because many hazardous waste management facilities were

contaminated from current or past solid and hazardous waste

management activities and required cleanup to protect humans

and the environment. As with the Superfund Program, some sites

subject to RCRA corrective action may be investigated and found

to require little or no cleanup, while others may be found to have

extensive soil, ground water, and/or sediment contamination. 

What the Data Show

EPA estimates that approximately 3,700 hazardous waste 

management facilities may be subject to cleanup under the

RCRA corrective action program (EPA, OSWER, October 2002).

To date, EPA and authorized states have identified approximately

1,700 hazardous waste management facilities that are the most

seriously contaminated and may pose significant threats to

human health or the environment (EPA, OSWER, October

2002). These sites typically have both soil and ground water

contamination and many also have contaminated sediments.

Some RCRA corrective action sites are also identified by the

Superfund Program as NPL sites. 

Indicator Gaps and Limitations 

RCRAInfo contains information about hazardous waste generators and management facilities in the U.S. and its territories.

RCRAInfo includes data on site location, status, contaminants

and contaminant sources, and actions taken. RCRAInfo provides

reliable data about the number and location of RCRA corrective

action sites and about cleanup priorities; however, information

on cleanup status at sites is less reliable, particularly for lower

priority sites. Cleanup status data for the 1,700 high priority

sites is current—particularly with respect to ongoing exposures

of humans to contamination and migration of contaminated

ground water, the two site conditions that the RCRA corrective

action program has chosen to track most closely. Also, there

are overlaps between the list of high priority RCRA corrective

action sites and NPL sites. Due to these overlaps, number-ofsite comparisons between programs and simple counts of 

contaminated sites can be misleading. 

Data Source

The data source for this indicator is EPA Office of Solid Waste and

Emergency Response, RCRA Info Data, 1997-1999. (See Appendix

B, page B-24, for more information.)

Indicator Number and location of RCRA corrective action sites – Category 2

3.3.4 What human health 

effects are associated with waste

management and 

contaminated lands?

While some types of waste (e.g., most food scraps) are not typically

toxic to humans, other types (e.g., mercury) pose dangers to human

health and must be managed accordingly. The number of substances

that exist that can or do affect human health is unknown; however,

the TRI program requires reporting of more than 650 chemicals and

chemical categories that are known to be toxic to humans.

The EPA Superfund Emergency Response Program and the Agency

for Toxic Substances and Disease Registry (ATSDR) have created

useful lists of common contaminant sources and their potential

health effects. Every 2 years, the ATSDR and EPA prepare a list, in

order of priority, of hazardous substances that are most commonly

found at the NPL sites and pose the most significant threat to

human health due to their known or suspected toxicity and potential

for human exposure (EPA, SERP, September 2002; ATSDR, 2001).

Arsenic, lead, and mercury are the highest ranking substances on the

list. All three of these substances are toxic to the kidneys, and lead

and arsenic can cause decreased mental ability, weakness, abdominal

cramps, and anemia (EPA, SERP, September 2002). Additional discussion of these substances is available in Chapter 4, Human Health.

EPA also maintains a separate list of common contaminants and their

potential health effects. The list includes commercial solvents,

household items, dry cleaning agents, and chemicals. With chronic

exposure, commercial solvents such as benzene, can suppress bone

marrow function and cause blood changes. Dry cleaning agents and

degreasers contain trichloroethane and trichloroethylene, which can

cause fatigue, depression of the central nervous system, kidney

changes (e.g., swelling, anemia), and liver changes (e.g., enlargement). Chemicals used in commercial and industrial manufacturing

processes such as arsenic, beryllium, cadmium, chromium, lead, and

mercury, are toxic to kidneys. Long-term exposure to lead can cause

permanent kidney and brain damage. Cadmium can cause kidney and

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.3 Waste and Contaminated Lands 3-51

lung disease. Arsenic, beryllium, cadmium, and chromium have been

implicated as human carcinogens (EPA, SERP, September 2002).

Contaminants can come into contact with humans through three

exposure pathways: inhalation, ingestion, and direct contact.

Exposure routes can vary for each substance. Chemicals can contaminate ground water due to leaking tanks, runoff, and leaching through

soil or sediment. In addition, the cleanup of sites contaminated with

radioactive materials has involved the remediation of approximately

1.7 trillion gallons of ground water—an amount equal to four times

the U.S. daily water consumption (DOE, 2000).

Information on waste generation amounts alone does not lead to a

complete understanding of the effects of waste on people and the

environment. The specific risks and burdens differ substantially from

waste type to waste type. For example, one pound of grass clippings

is not "equal" in terms of potential risk in exposure to one pound of

dioxin. Exposure to waste is likely to vary as a function of management practices: treatment, storage, transfer, and disposal actions.

Waste that is efficiently and safely treated and disposed of is likely

to have relatively little effect on human health. No specific indicators

have been identified at this time. Additional discussion of the human

health effects associated with waste management and contaminated

lands is found in Chapter 4, Human Health.

3.3.5 What ecological effects are

associated with waste management

and contaminated lands? 

Hazardous substances can have negative effects on the environment by degrading or destroying wildlife and vegetation in 

contaminated areas, causing major reproductive complications in

wildlife, or otherwise limiting the ability of an ecosystem to survive.

Certain hazardous substances also have the potential to explode 

or cause a fire, threatening both wildlife and human populations

(EPA, SERP, September 2002).

Waste from extraction activities can contaminate water, soil, and air;

affect human health; and damage vegetation, wildlife, and other

biota. Toxic residues left from mining operations can be transported

into nearby areas, affecting resident wildlife populations. This type of

damage is often the result of unlined land-based units that have minimal release controls. These units include surface impoundments

containing mill tailings and/or process wastewater, heap-leaching

solution ponds, dusts, piles of slags, refractory bricks, sludge, waste

rock/overburden, and spent ore. Spills and leaks from lined management units, valves, and pipes also are known to occur. 

Contaminated lands can pose a threat depending on several factors

such as site characteristics and potential exposure of sensitive 

populations. The negative effects of land contamination on 

ecosystems and wildlife occur after contaminants have been released

on land (soil/sediment) or into the air or water. Often, land contamination leads to water or air contamination by means of gravity, wind,

or rainfall. No specific indicator was identified at this time.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-52 3.4 Challenges and Data Gaps Chapter 3 - Better Protected Land

3.4 Challenges and 

Data Gaps 

Many of the specific data gaps related to development of the

described indicators and their ability to answer the questions posed

have already been identified. The discussion below augments the

previously identified gaps. 

3.4.1 Land Use

The ability to accurately characterize and track land use over time is

limited. Various federal efforts, such as the USDA NRCS, NRI, the

USDA Forest Service FIA, the U.S. Fish and Wildlife Service (USFWS)

Status and Trends Program, and the NLCD, contribute in part to

tracking some land uses and a variety of cover types. None of 

these are comprehensive for all lands or land uses, and some have

limitations in their frequency of data collection or analysis. Some

cover types and land uses are not sampled in any detail, including

private and federal desert lands, federal shrublands and grasslands,

and rangeland. In addition, Alaska is seldom included in national

inventories, although Alaska represents approximately 16 percent 

of the land area of the U.S. and includes extensive shrublands, 

grasslands, and tundra. 

Each of the national systems has developed different methods, 

definitions, and classification criteria. While some effort has been

made to share definitions across some of these systems (e.g., the

NRI and FIA systems use essentially the same definition of forest

land, and NRI and FWS define wetlands similarly), not all are 

consistent, especially in descriptions of developed or urban land,

cropland, and rangeland. Examples of differences in classifications

and acreage from several current national efforts are shown in

Exhibit 3-31 for developed and agricultural land uses. The NLCD

uses different classification and land use definitions because it is

based on remote sensing data (an aerial perspective) rather than 

on ground sampling. FWS information is also based on aerial photo

interpretation. Given the increasing availability of high resolution

aerial imagery, remotely sensed techniques for land cover delineations are likely to increase and classifications based on this 

inventory approach should be coordinated and defined. 

Another challenge is developing data on uses and cover types that 

at present are not adequately sampled. Further challenges include

effectively integrating and harmonizing the various results of 

multi-agency, as well as state and local, efforts and coordinating the

limited resources dedicated to national tracking of land cover/land

use changes among agencies, so that inventories can be performed

as frequently and as comprehensively as possible. The overarching

goal is to assess national patterns in such a way that changes in land

cover and land use that might have implications for human health or

ecological condition can be detected and addressed. 

Exhibit 3-31: Land cover/land use estimates

U.S. Census BureauC 47 million acres urbanized areas

13 million acres urban clusters

No data

The Heinz CenterB 32 million acres urban and suburban land 430-500 million acres cropland, hayland, and pastureland

National Resources Inventory 

(NRI)A

98 million acres developed land 377 million acres cropland

32 million acres Conservation Reserve Program land

120 million acres pastureland

National Land Cover Data 

(NLCD)D

36.7 million acres low and high density 

residential and commercial/industrial/ 

transportation

331 million acres cropland

179 million acres pastureland and hayland

Data Source Developed Land Agricultural Land

Note: The NRI, Heinz Center, and NLCD sources do not include Alaska as part of the estimates.

A USDA, Natural Resources Conservation Service. Summary Report: 1997 National Resources Inventory (Revised December 2000). 2000.

B The Heinz Center. The State of the Nation's Ecosystems. 2002.

C U.S. Census Bureau. Corrected Lists of Urbanized Areas and Urban Clusters. November 25, 2002. (March 2003; http://www.census.gov/geo/www/ua/ua_state_corr.txt and 

http://www.census.gov/geo/www/ua/uc_state_corr.txt).

D USGS, National Land Cover Dataset. NLCD Land Cover Statistics. 2001. (March 2003; http://landcover.usgs.gov/nlcd.html).
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 3 - Better Protected Land 3.4 Challenges and Data Gaps 3-53

The data available that actually summarize a national picture of land

use are extremely limited. Relatively little comprehensive information

exists about federal land management practices and extent. For

example, while the USDA Forest Service tracks acres managed for

timber production, data are not easily accessible on acres used for

grazing; oil, gas, and mineral development; or recreation. Data 

needed to summarize all lands under some form of "protection,"

such as parks, wilderness areas, reserves, or conservation easements

at all levels of government, do not exist.

In many cases, where land is used to produce food or fiber, indicators that report the amounts and values of these commodities might

be used to identify the condition/stress/pressure on the land.

Examples of commodities include agricultural products, forest 

products, and cattle produced from grazing land. The amount of

fresh water used by humans might also be a good indicator of the

pressure being applied to land and water resources. Commodity 

production is commonly correlated closely to population growth.

Reporting of commodity production trends in agriculture and

forestry might also provide another view of the effects of these

activities on the land and help evaluate policy options for ensuring

long term, sustainable commodity production while reducing 

environmental effects. 

Land provides many other benefits in addition to commodity production. Research is being conducted on the subject of quantifying

these "ecosystem services." Indicators are needed that will enable

measuring and tracking some of these services. 

3.4.2 Chemicals

Most of the national efforts to track chemical usage focus on how

much is produced, used, or released, with less emphasis on tracking

the extent or area of use. The TRI database requires reporting of

releases of certain volumes of specific chemicals, but aside from

knowing the location of initial releases, it does not track the extent

of the area that might in some way be affected by the chemicals. 

In addition, pesticide and fertilizer use are primarily tracked by

understanding where these chemicals are sold, rather than where

they are actually used. 

Further, not all toxic chemicals are on the list of TRI chemicals and,

therefore, some toxics are not reported. The TRI program faces the

challenge of maintaining a current list that reflects the constant

development, use, and release of new chemicals that might have

effects on human and ecological health.

Indicators for pesticide residue in food, potential pesticide runoff

from farmlands, risk of nitrogen runoff, and risk of phosphorus runoff

all address some part of the question of potential chemical

disposition. Only the indicator for pesticide residues in food,

however, goes beyond stating the potential for chemicals to leave

their point of use and actually shows the potential for consumers to

be exposed to these chemicals. Indicators to better understand the

actual disposition of chemicals, rather than potential disposition,

would be useful to correlate with actual human health and ecological

condition indicators. 

Better indicators of the linkages between chemical applications on

the landscape and chemicals that find their way into the bodies of

humans and other species are needed. This includes better information on the chemistry, quantities, and longevity of various substances; on the cumulative effects of various chemicals on the environment and humans; and on the pathways and effects of exposure.

In cases where nutrients do reach receiving waterbodies and raise the

concentrations above background levels, considerable uncertainty

still exists concerning ultimate ecological effects. Current research

does not clearly quantify the relationship between raised nutrient

levels and resulting ecological changes. 

Better information is needed to provide an accurate picture of the

human health effects of pesticide use. This information is difficult to

collect, however. Even in California, where significant resources are

dedicated to pesticide regulation, the best available indicator is a

measure of reported illnesses and injuries from pesticide exposure in

the workplace. While this is valuable information, it does not address

potential long-term health effects of non-workplace exposure that

might result through drinking water and food exposure.

State Pesticide Use Reporting Systems

While there is no national pesticide use reporting system, several

state systems exist. For example, California, with the most

advanced system in the country, has had full pesticide use

reporting since 1990. Reports about the specifics of application

are filed by large- and small-scale farmers, commercial agricultural

pesticide applicators, structural pest control companies, and

commercial landscaping firms. (California Department of

Pesticide Regulation, 2000.)
EPA’s Draft Report on the Environment 2003 ■ Technical Document

3-54 3.4 Challenges and Data Gaps Chapter 3 - Better Protected Land

3.4.3 Waste and Lands Used for Waste Management 

Several challenges and data gaps limit the understanding of waste

and its effects on human health and ecological condition. First, as

noted, waste data tend to be developed in response to the requirements of specific mandates or regulations. Because these regulations

do not apply to all types of waste and are carried out at different

levels of government, and in the private sector, complete data do 

not exist to answer the question: "How much waste is generated?"

Additionally, most waste generation is reported only by weight, 

providing little understanding of the volume of waste produced.

Information about the amount of waste generated does not provide

a complete picture on either the extent of waste-related problems or

the effects of waste on human health, ecosystems, or the ambient

environment. Different waste types pose substantially different types

of risks. Some wastes are known to be hazardous to humans and the

environment, but specifics about exposures and the effects of many

other waste types are not well understood and data are limited.

Finally, the risks posed by waste are largely a function of the type

and effectiveness of waste management. The available data on waste

and waste management have been limited by the stringent regulatory

requirements and definitions that have driven most of the national

information collection efforts. 

Data to describe how lands are affected by waste management are

also limited. Even basic statistics on the acreage of lands used for

managing waste and the condition of those lands are not available

at the national level. To gain a more complete understanding of

the extent and effects of land used for waste management would

require information on waste management methods, standards,

and compliance, as well as information on lands where illegal

dumping occurs. Establishing linkages to human populations or

ecosystems within close proximity to lands managed for waste is

an additional challenge. 

3.4.4 Contaminated Land

Today, the best available information used to describe extent of 

contaminated land includes measures of the number and location of

sites. two indicators of contaminated land that lack national-quality

data are the extent of contaminated land and the effects of 

contamination.

Determining the extent of contaminated land would require nationallevel information on the number, location, and area of contaminated

lands, and data on the specific site contaminants and the associated

risks, hazards, and potential exposures. Additional factors such as the

potential contamination of ground water sources and the

transportation or disposal methods needed to clean up the

contamination would have to be considered. Such data are currently

captured for only a subset of the nation's contaminated lands. In

addition, information on known contaminated lands (e.g., some sites

in EPA's Comprehensive Environmental Response, Compensation,

and Liability Information System) that are not on the Superfund's

NPL, data in state and local databases, and information on the other

types of contaminated lands (e.g., leaking underground storage

tanks) are not captured in the existing data.
Chapter 4:

Human Health
Indicators that were selected and included in this chapter were assigned to one of two categories:

■ Category 1 –The indicator has been peer reviewed and is supported by national level data coverage for more than one time period.

The supporting data are comparable across the nation and are characterized by sound collection methodologies, data management

systems, and quality assurance procedures.

■ Category 2 –The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multi-state

regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of the

indicator have been measured (e.g., data has been collected for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by sound collection methodologies, data management systems, and

quality assurance procedures.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.0 Introduction 4-3

4.0 Introduction

The U.S. Environmental Protection Agency (EPA) is moving in the

direction of measuring and assessing human health and ecological

outcomes. Traditionally, EPA has used indicators such as decreases

in emissions/discharges or decreases in ambient pollutant levels to

measure environmental improvement. Health outcome measures

complement these traditional approaches by reflecting the actual

public health or ecological impacts that result from environmental

pollution. By providing a quantitative assessment of these impacts,

outcome indicators can strengthen environmental decision-making

and enhance EPA’s ability to evaluate, prospectively or retrospectively, the success of those decisions.

The key to using outcome-based indicators is a clear understanding

of the sequence of events that link changes in environmental 

conditions to health or ecological outcomes. Exhibit 4-1 depicts

this sequence for human health. Each block in the diagram can 

have indicators associated with it. Indicators for the presence of

pollutants or other stressors affecting air, water, and land are 

covered in Chapters 1 (Cleaner Air), 2 (Purer Water), and 

3 (Better Protected Land), respectively, of this report. Indicators for

the presence of pollutants in the body and their effects on health

(altered structure or function, morbidity, or mortality) are covered

in this chapter. 

The paradigm depicted in Exhibit 4-1 underlies the science upon

which EPA bases its risk assessment process (NRC, 1983). Risk

assessments, to a large degree, seek to estimate all linkages depicted

in the exhibit. However, understanding the link between human exposure and health outcomes has always been challenging. Decades of

research have provided the scientific foundation for understanding

how exposure to individual pollutants at elevated levels may affect

human health. There is less certainty, however, about the effects of

ambient exposures, which typically involve exposure to multiple 

pollutants at lower levels. Improved understanding of the linkages

between these exposures and public health would strengthen EPA’s

ability to make and evaluate decisions. 

The indicators that describe the public health consequences of 

environmental exposures are called environmental public health 

indicators (EPHIs). Numerous national and international organizations have recognized the compelling need for EPHIs. The greatest

impetus came from a series of reports, by the Pew Environmental

Source: Modified from National Research Council. Risk Assessment in the Federal Government: Managing the Process. 1983

Exhibit 4-1: Environmental public health paradigm

Pollutant Formation 

and Release 

from Source

Transport/ 

Transformation

Altered Structure/ 

Function

Exposure/Contact

- Individual

- Community

- Population Air, Water, and Land Chapters

Entry into Body 

(Dose)

Biomonitoring 

Indicators

Health Outcome 

Indicators

Adverse Outcomes: 

Mortality and 

Morbidity 
Technical Document ■ EPA’s Draft Report on the Environment 2003

4-4 4.0 Introduction Chapter 4 - Human Health

Health Commission, which called on “Congress and the White House

to protect Americans from chronic diseases—by tracking where and

when these health problems occur and possible links to environmental factors.” The commission proposed that a Nationwide Health

Tracking Network be established to track selected diseases and 

priority environmental exposures (Pew, 2001). When combined with

other information, such as environmental monitoring data and data

from toxicological, epidemiological, or clinical studies, EPHIs can be

an important key to improving understanding of the relationship

between pollution and health outcomes.

Two types of environmental public health indicators are described 

in this chapter:

■ Health outcome indicators. These indicators measure the occurrence in a population of diseases or conditions that are known or

believed to be caused to some degree or exacerbated by exposure

to environmental pollutants or stressors.

■ Exposure indicators. While there are four types of exposure 

indicators (see sidebar), this chapter focuses on biomonitoring

indicators, which involve using tests of human fluid and tissue 

samples to identify the presence of a substance or combination 

of substances in the human body.

For some of the EPHIs described in this chapter, a strong linkage has

been established between environmental exposure and outcome.

However, for many of the EPHIs presented, such as the outcome

indicator of overall mortality, no linkage between environmental

exposure and outcome has been determined. For these, further

research would be needed to establish and strengthen any linkages.

Similarly, for some EPHIs, the linkage with the source of the pollution

is clear (e.g., lead in gasoline), while for others the source or sources

are much less certain.

Use of Environmental Public Health

Indicators

Environmental public health indicators can be used to:

■ Describe the health status of a population and discover

important time trends in disease and exposure frequency.

Most, if not all, of the indicators presented in this chapter 

perform this function.

■ Explain the occurrence or prevalence of diseases and exposure

by helping to identify causal factors for specific diseases or

trends. For example, the decline in the lung cancer rate in men

has been related to the decline in smoking. For some areas

presented in this chapter, the evidence for a relationship is

quite strong (e.g., air pollution and pulmonary-cardiovascular

related-illnesses). Other areas will require further research to

better understand these linkages.

■ Predict the number of disease occurrences and the distribution of exposure in specific populations. Such predictions

could be used, for example, as input for setting priorities and

making decisions to protect public health—e.g., establishing

cleanup levels for environmental waste sites or regulatory levels

for ambient pollutant levels. (Understanding the relationship

between exposure and consequent health effects is critical to

using indicators for predictive purposes.)

■ Evaluate policy decisions or interventions. (Again, understanding the relationship between exposure and effect is critical for

this use.) 

Types of Exposure Indicators

Four approaches can be used to measure or estimate exposure

(i.e., direct human contact with a pollutant). No approach is

best suited to all pollutants. Different approaches are

appropriate to different types of pollutants, and each approach

has strengths and weaknesses. 

■ Ambient pollutant measurements. Historically,

environmental measurements of ambient pollutant

concentrations have generally been used to estimate human

exposures. One limitation of ambient measurements is that

the presence of a pollutant in the environment does not

necessarily mean that anyone has been exposed. Chapters 1

(Cleaner Air), 2 (Purer Water), and 3 (Better Protected

Land) provide examples of ambient measurement indicators. 

■ Stochastic models of exposure. This approach combines

knowledge of environmental pollutant concentrations with

information on people's activities and locations (e.g., time

spent working, exercising outdoors, sleeping, shopping) to

account for their contact with pollutants. This approach

requires knowledge of pollutant levels where people live,

work, and play, as well as knowledge of the choices that they

make in regard to day-to-day activities.

■ Personal monitoring data. With personal monitoring, the

monitoring device is worn by individuals as they proceed

through their normal activities. This approach is most

common in workplaces. Personal monitoring data provide

valuable insights into the sources of the pollutants to which

people are actually exposed. However, a challenge with

personal monitoring (as with biomonitoring) is ensuring that

sufficient sampling is done to be representative of the

population being studied.

■ Biomonitoring data. Several environmental pollutants,

notably heavy metals and some pesticides, can be found in

the body. These pollutants or their breakdown products (i.e.,

metabolites formed when a pollutant is broken down in the

body) leave residues that can be measured in human tissue

or fluids such as blood or urine. These residues reflect the

amount of the pollutant that actually gets into the body, but by

themselves they provide no information on how the individual

came into contact with the pollutant.
One of the greatest challenges to elucidating the connection between

environmental exposure and disease is the fact that exposure to an

environmental pollutant or stressor is rarely the sole cause of an adverse

health outcome. More generally, individuals are exposed to more than

one pollutant at a time, and exposure is just one of several factors that

contribute to the disease occurring or to the severity of a preexisting

disease. Other factors include, for example, diet, exercise, alcohol

consumption, heredity, medications, and whether other diseases are also

present. Also, different people have different vulnerabilities, so some may

experience effects to certain ambient exposure levels while others may

not. All these factors make it difficult to establish a causal relationship

between exposure to environmental pollutants and disease outcome

except in rare cases, such as some historical occupational exposures,

where exposure was unusually high.

This chapter presents a broad spectrum of indicators that can now be

used, or could potentially be employed in the future, to assess and track

the public health impacts of environmental exposures. These indicators

provide an overview of the health and exposure of people in the U.S.

and identify the trends of those indicators in the U.S. Specific indicators

for exposure and outcomes in children are presented, as children may

be especially susceptible to environmental pollutants.

This chapter is organized into six sections: 

■ Section 4.1 describes three case studies that illustrate the role of

indicators in establishing linkages between effects and outcomes

and in evaluating environmental management actions.

■ Section 4.2 compares health measures within the U.S. to these

same measures throughout the rest of the world.

■ Section 4.3 discusses outcome indicators and trends for selected

diseases that either have a major impact on the health of people

in the U.S. or may be caused to some extent by environmental

pollution. Exhibit 4-2 lists the key public health questions that are

asked in this section and the indicators that are available to help

answer these questions. 

■ Section 4.4 presents biomonitoring indicators and trends for specific environmental pollutants. The section begins by providing

background on biomonitoring indicators and their limitations and

data sources. The section then presents biomonitoring indicators

for numerous specific pollutants and discusses other important

pollutants for which biomonitoring data are not yet available.

Exposure information for many of these pollutants is discussed in

Chapters 1 (Cleaner Air), 2 (Purer Water), and 3 (Better

Protected Land) of this report. The key exposure questions asked

in this section and the indicators available to help answer these

questions are presented in Exhibit 4-2. 

■ Section 4.5 discusses an emerging field that attempts to quantify

the overall burden of environmental disease on society.

■ Section 4.6 discusses the key challenges and data gaps for

understanding the link between environmental exposure and

health outcomes, and some recent government activities to 

continue and advance the work in this area.

Many federal and state government agencies collect data that

underlie environmental public health indicators. Continued effective

coordination and collaboration among such agencies will be vital to

further the development and use of environmental public health

indicators. Key data sources used for this chapter include the:

■ World Health Organization (WHO), World Health Statistics

Annual, a joint effort by the national health and statistical administrations of many countries, the United Nations, and WHO.

■ United Nations, Demographic Yearbook, a comprehensive 

collection of international demographic statistics compiled from

questionnaires sent annually and monthly to national statistical

services and other government offices.

■ National Center for Health Statistics, National Vital Statistics

System, which provides data on births, deaths, marriages, and

divorces in the U.S. since 1933. 

■ National Center for Health Statistics, National Health

Interview Survey (NHIS), a continuous nationwide survey in

which data on personal and demographic characteristics, illnesses,

injuries, impairments, chronic conditions, utilization of health

resources, and other health topics are collected through personal

household interviews.

■ Centers for Disease Control and Prevention, Epidemiology

Program Office, National Notifiable Diseases Surveillance

System, which provides weekly provisional information on the

occurrence of diseases defined as notifiable (i.e., a disease 

that health providers must report to state or local public health

officials due to its contagiousness, severity, or frequency).

■ National Institutes of Health, National Cancer Institute,

Surveillance, Epidemiology, and End Results Program,

which provides data on all residents diagnosed with cancer in 

11 geographic areas of the U.S.

■ The EPA’s National Human Exposure Assessment Survey

(NHEXAS), a multiday, multimedia study that examined 

chemical concentrations in indoor air, outdoor air, dust, soil, food,

beverages, drinking water, and tap water. 

■ National Center for Health Statistics, National Health and

Nutrition Examination Survey (NHANES), a series of surveys

designed to collect data on the health and nutritional status of

the U.S. population. Chemicals and their metabolites were 

measured in blood and urine samples from selected participants.

The chapter is not intended to be exhaustive. Rather, it provides a

snapshot, at the national level, of the current U.S. environmental

public health indicators and status based on key data sources with

sufficiently robust design, quality assurance, and maturity. The 

chapter does not provide health status information that may be

more applicable to certain geographic areas or to subgroups with

potentially greater susceptibility to environmental pollution due to

such factors as age, genetics, lifestyle, or medical status.

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Chapter 4 - Human Health 4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes 4-5
4-6 4.0 Introduction Chapter 4 - Human Health

Question Indicator Name Category Section

Measuring Exposure to Environmental Pollution: Indicators and Trends

 Blood lead level 1 4.4.3

 Urine arsenic level 2 4.4.3

 Blood mercury level 1 4.4.3

 Blood cadmium level 1 4.4.3

 Blood cotinine level 1 4.4.4

 Blood volatile organic compound levels 1 4.4.5

 Urine organophosphate levels to indicate pesticides 1 4.4.6

 No Category 1 or 2 indicators identified 4.4.7

 Blood lead level in children 1 4.4.8

 Blood mercury level in children 1 4.4.8

 Blood cotinine level in children 1 4.4.8

 No Category 1 or 2 indicators identified 4.4.9

 No Category 1 or 2 indicators identified

Also see Cleaner Air chapter 4.4.9

 No Category 1 or 2 indicators identified 4.4.9

 No Category 1 or 2 indicators identified 4.4.9

Exhibit 4-2: Human Health - Questions and Indicators

Health Status of the U.S. : Indicators and Trends of Health and Disease

Question Indicator Name Category Section

 Life expectancy 1 4.3.1

 Cancer mortality 1 4.3.2

 Cancer incidence 2 4.3.2

 Cardiovascular disease mortality 1 4.3.2

 Cardiovascular disease prevalence 1 4.3.2

 Chronic obstructive pulmonary disease mortality 1 4.3.2

 Asthma mortality 1 4.3.2

 Asthma prevalence 1 4.3.2

 Cholera prevalence 2 4.3.3

 Cryptosporidiosis prevalence 2 4.3.3

E. coli O157:H7 prevalence 2 4.3.3

 Hepatitis A prevalence 2 4.3.3

 Salmonellosis prevalence 2 4.3.3

 Shigellosis prevalence 2 4.3.3

 Typhoid fever prevalence 2 4.3.3

 Infant mortality 1 4.3.4

 Low birthweight incidence 1 4.3.4

 Childhood cancer mortality 1 4.3.4

 Childhood cancer incidence 2 4.3.4

 Childhood asthma mortality 1 4.3.4

 Childhood asthma prevalence 1 4.3.4

 Deaths due to birth defects 1 4.3.4

 Birth defect incidence 1 4.3.4

What is the level of exposure to cotinine? 

What is the level of exposure to volatile organic compounds? 

What is the level of exposure to pesticides? 

What is the level of exposure to persistent 

 organic pollutants? 

Question Indicator Name Category Section

What are the trends for life expectancy? 

What are the trends for cancer, cardiovascular disease, 

 chronic obstructive pulmonary disease and asthma? 

What are the trends for gastrointestinal illness? 

What are the trends for children's environmental health issues? 

What are the trends in exposure to environmental 

 pollutants for children?

What is the level of exposure to radiation? 

What is the level of exposure to air pollutants?

What is the level of exposure to biological pollutants? 

What is the level of exposure to disinfection by-products? 

What is the level of exposure to heavy metals?

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes 4-7

4.1 Environmental Pollution

and Disease: Links

Between Exposure and

Health Outcomes

Many studies have demonstrated an association between environmental exposure and certain diseases or other health problems.

Examples include radon and lung cancer; arsenic and cancer in 

several organs; lead and nervous system disorders; disease-causing

bacteria such as E. coli O157:H7 (e.g., in contaminated meat and

water) and gastrointestinal illness and death; and particulate matter

and aggravation of cardiovascular and respiratory diseases. 

As mentioned in Section 4.0, indicators of outcome and exposure

can be important tools both for elucidating these links and monitoring the success of environmental management efforts. Indicators are

one of several components needed to establish linkage. Other 

important components include ambient pollutant measures and toxicological, epidemiological, and clinical studies. Three case studies 

are described in this section to demonstrate how indicators can be

used to establish associations between exposure and effect and to

evaluate environmental management actions.

Case Study on Waterborne Disease

This case study focuses on the impact of drinking

water treatment on the decrease in mortality related

to waterborne diseases. It demonstrates the valuable

contribution to public health protection that can

occur when the link between exposure and health 

outcomes is successfully made. As the case study

describes, officials knew there was a high incidence of

gastrointestinal disease, but they were not able to

protect human health until they understood what

caused these diseases. Based on this connection, 

officials were able to take effective action to protect

public health. They also were able to use an outcome

measure (deaths due to typhoid) to evaluate the 

success of these protective actions. 

At the beginning of the 20th century, waterborne

diseases such as typhoid fever and cholera were

major health threats across the U.S. More than

150 in every 100,000 people died from typhoid

fever each year. Deaths due to diarrhea-like illnesses, including

typhoid, cholera, and dysentery, represented the third largest cause

of death in the nation. 

Then scientists identified the bacteria responsible for most diarrhea

deaths (typhoid, cholera, and dysentery) and elucidated how these

bacteria were transmitted to and among humans. Infected and

diseased individuals shed large quantities of microbes in their feces,

which flowed into and contaminated major water supplies. The

contaminated water was then distributed untreated to communities,

which used the water for drinking and other purposes. This created a

continuous transmission cycle. 

When treatment (filtration and chlorination) of drinking water was

initiated to remove pathogens, the number of deaths due to 

diarrhea diseases dropped dramatically. Deaths due to typhoid fever

were tracked throughout the early 20th century, as drinking water

treatment was implemented across the country. Exhibit 4-3 shows

the percent of the U.S. population that had treated water and the

disease rate for typhoid fever from 1880 to 1980.

In this example, the outcome measure was death rates due to

typhoid, which was used in conjunction with an environmental

process (the number of people getting treated drinking water) 

to evaluate and promulgate the use of drinking water treatment

across the U.S.

Drinking water treatment was one of the great public health success

stories of the 20th century (NAE, 2000). It dramatically and

significantly reduced death rates from waterborne disease, increasing

Exhibit 4-3: Percent of population with treated water 

versus typhoid deaths in the United States, 1880-1980

Typhoid deaths per 100,000 people

100

10

1

90

80

70

60

50

40

30

20

10

0

1880 1890 1900 1920 1930 1940 1950 1960 1970 1980

Year

Source: Craun, C.G. Waterborne Diseases in the United States. 1986; Whipple, G.C. Typhoid Fever - Its 

Causation. Transmission and Prevention. 1908; Fox, K. National Risk Management Research Laboratory, 

personal communication, 2003. 

Deaths

Percent

Percent of population with treated water 
4-8 4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes Chapter 4 - Human 

life expectancy and reducing infant mortality. Today, public health is

protected against new and emerging waterborne microbial

contaminants by continual improvements to the drinking water

treatment process and continual monitoring of waterborne diseases.

Deaths due to cholera, typhoid, and dysentery are so rare in this

country that they do not provide valuable information for evaluating

the public health impacts of drinking water treatment. Instead, the

number of cases of these diseases are tracked to some extent,

although reporting is not federally required. Indicators for

waterborne disease and other important diseases with actual or

potential environmental origins are discussed in Section 4.3.

Case Study on Air Pollution

This case study illustrates how the association between deaths and peak

air pollution concentrations was initially discovered by comparing mortality rates and air monitoring data. It also describes how basic research on

the health effects of air pollution has helped to establish strong linkages

between levels of certain air pollutants and human health effects. These

associations have provided sufficient basis for establishing regulations to

control the level of pollutants in air. The success of these environmental

management efforts can be evaluated by monitoring levels of regulated

pollutants in air. However, except for lead (the subject of the third case

study below), there are as yet no biomonitoring or outcome indicators

that can more directly measure reduced human exposure or outcome on a

national level. Nevertheless, a number of potential outcome indicators are

discussed that could be available in the future if systems can be set up to

track relevant biomonitoring or outcome data with sufficient reliability

and coverage at a national level. 

Air pollution has been associated with several human health outcomes, including reported symptoms (nose and throat irritation),

acute onset or exacerbation of existing disease (e.g., asthma, hospitalizations due to cardiovascular disease), and deaths. The impact of

air pollution on health was underscored in London in December of

1952, when a slow-moving area of high pressure came to a halt over

the city. Fog developed, and particulate and sulfur pollution began

accumulating in the stagnating air mass. Smoke and sulfur dioxide

concentrations built up over 3 days. Mortality records showed that

deaths increased in a pattern very similar to that of the pollution

measurements. (This is illustrated in Exhibit 4-4.) It was estimated

that 4,000 extra deaths occurred over a 3- to 4-day period. This

was the first quantitative air pollution exposure data with a link to an

adverse health outcome (i.e., mortality). 

While the London episode highlighted the hazard of extreme air 

pollution episodes, it was unclear whether health effects were 

associated with lower concentrations. By the 1970s, the association

between respiratory disease and particulate and/or sulfur oxide air

pollution had been well established (Dockery and Pope, 1997). 

Clinical studies (controlled studies in healthy adult subjects) also

provide information about the association between air pollutants and

health effects. For example, these studies have demonstrated that

ozone causes a number of functional, symptomatic, and inflammatory

responses, which tend to increase with an increase in ozone exposure

dose (EPA, 1996). Effects of ozone include:

■ Decreased pulmonary function, characterized by changes in lung

volumes and flow; changes in airway resistance and

responsiveness; and respiratory symptoms, such as cough and 

pain on deep inspiration (EPA, 1996). 

■ An inflammatory response in the lungs (EPA, 1996). 

Based on these types of associations from toxicological, epidemiological, and clinical studies, EPA has established National Ambient Air

Quality Standards for six pollutants of concern: ozone, particulate

matter, carbon monoxide, lead, nitrogen dioxide, and sulfur dioxide.

These standards set limits to protect human health, including the

health of “sensitive populations” such as asthmatics, children, and

the elderly (EPA, 1999). 

Improvements in measuring air pollution and health endpoints,

together with advances in analytical techniques, have made it

possible to begin to quantitatively evaluate the success of air

pollution control measures—such as the National Ambient Air

Quality Standards and associated regulations—to protect and

improve public health. Though insufficient data were available at the

time of this report to develop EPHIs for any criteria pollutants

except lead, possible future EPHIs for air pollution include death due

to respiratory and cardiovascular disease as well as increased hospital

admissions for respiratory and cardiovascular disease. 

EPA’s Draft Report on the Environment 2003 ■ Technical Document

1 2 3 4 5 6 7 8 9 10 12

Day of December, 1952

6

3

2

1

0

1,000

600

400

200

Smoke (mg/m3)

Deaths

4

5

800

11 13 14 15

Exhibit 4-4: London fog episode deaths, 1952

Source: Based on Dockery, D.W. and C.A. Pope. Outdoor Air I: Particulates. 1997.

Smoke

Deaths
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes 4-9

Future EPHIs include:

■ Mortality. In many countries including the U.S., particulate air

pollution has been associated with increased daily mortality from

heart and lung diseases (e.g., congestive heart disease, chronic

obstructive lung disease). In addition, chronic exposure to air 

pollution has been linked with increased risk of premature 

mortality (EPA, April 2002).

■ Hospital admissions. Hospitalization records are not widely 

available, and studies have been limited by their availability in

communities around the U.S. Nevertheless, many studies have

shown that increased admissions for cardiovascular and respiratory

diseases are associated with increased pollutant concentrations. 

Most recently, subtle changes in the cardiovascular system that 

can increase a person’s risk of heart attack and bring about other

cardiovascular effects have been identified as possible EPHIs.

Establishing EPHIs for air pollution and health effects, whether

cardiovascular or pulmonary, is still challenged by limits in knowledge

of how much air pollution contributes to the risk of both

cardiovascular and respiratory disease. Research is still needed to

better understand which components of air pollution (i.e., gases,

metals, or organics) cause health effects; the extent to which they

contribute to risk; and the extent to which other factors (e.g.,

genetics, lifestyle, age) contribute to risk. Given these limitations, no

indicators are presented for any of the six criteria pollutants except

lead. A case study on lead is presented below, with further

discussion on lead as an indicator provided in Section 4.4. 

Case Study on Lead

The third case study concerns lead, a toxic pollutant to which there is

human exposure from many different sources. In the previous case studies,

outcome indicators were an important key to establishing a linkage

between a health effect and its cause. Understanding the cause enabled

officials to take action to protect public health. In the case of lead,

though it was a known toxin, exposure came from so many sources that it

was difficult to know what actions at the national level would effectively

reduce lead exposure. Once regulations to do so were put in place, 

biomonitoring data provided a way to evaluate the success of this 

environmental management effort in reducing exposure to lead in the U.S. 

Lead is a neurotoxic metal that affects areas of the brain that regulate behavior and nerve cell development (NAP, 1993). Its adverse

effects range from subtle responses to overt toxicity, depending on

how much lead is taken into the body and the age and health status

of the person (CDC, 1991). 

Currently in the U.S., human exposure to lead may occur in several

ways, as listed in Exhibit 4-5. For example:

■ Homes built before 1978, commercial buildings, and steel structures may contain deteriorating lead-based paint, which creates

lead-contaminated dust (EPA, 1996). An estimated 24 million

housing units in the U.S. are at risk for containing some lead paint

hazards (U.S. Department of Housing and Urban Development,

2000). Of these, 16 million homes with lead-based paint have

children in residence who are younger than 6 years old. 

■ Other sources of lead exposure include lead-contaminated soil,

dust, and drinking water; industrial emissions; and miscellaneous

sources (CDC, 1991). 

For many years, the largest source of lead in the U.S. environment

came from leaded gasoline. Elemental lead was emitted in the

exhaust and settled on the ground and in people’s homes. 

Most lead enters the body via ingestion and inhalation, after which it

is absorbed by the bloodstream. Also, lead can cross the placenta,

exposing the fetus to lead (EPA, 1996). In adults, most lead poisoning is associated with occupational exposures.

Infants, children, and fetuses are more vulnerable to the effects of

lead because their blood-brain barrier is not fully developed

(Nadakavukaren, 2000). In addition, ingested lead is more readily

absorbed into a child’s bloodstream. Children absorb 40 percent of

ingested lead into their bloodstreams, while adults absorb only 10

percent. In children, three major organ systems are affected by lead:

the nervous system (the brain), the kidney, and the blood-forming

organs (NRC, 1993). 

Exhibit 4-5: Sources of lead exposure 

in the United States

Lead-based paint

Lead-contaminated 

soil and dust

Lead-contaminated 

drinking water

Miscellaneous

Homes (built before 1978)

Commercial buildings

Steel structures (bridges, water towers)

Industrial emissions

Past leaded gasoline use

Deteriorating lead-based paint

Leaded plumbing solder

(now banned)

Home hobbies - art, jewelry, 

fishing weights

Use of pewter dishware

Cosmetics, traditional medicines

Parental occupations

Source: CDC. Preventing Lead Poisoning in Young Children. 1991.
4-10 4.1 Environmental Pollution and Disease: Links Between Exposure and Health Outcomes Chapter 4 - Human Health

As awareness of the health effects of lead has increased, the CDC

has lowered the level considered to be a human health hazard

(Exhibit 4-6) (CDC, 1991). In 1970, a blood lead level of 40 micrograms per deciliter (μg/dL) or higher was considered a hazard.

Today, 10 μg/dL or higher is considered a hazard (EPA, December

2000). Recent research suggests that blood lead levels less than 10

μg/dL may still produce subtle, subclinical health effects in children

(Schmidt, 1999). In 1984, an estimated 6 million children and

400,000 fetuses were exposed to lead at levels that placed them at

risk for adverse effects (NAP, 1993). Approximately 4.4 percent of

all U.S. children in the 1990s had elevated blood lead levels (NCEH,

1998). As of 1998, an estimated 1 million U.S. children had blood

lead levels above 10 μg/dL (NCEH, 1998).

Lead is one of the few pollutants for which biomonitoring and linkage data are sufficient to clearly evaluate environmental management

efforts to reduce lead in the environment. The National Center for

Health Statistics’ National Health and Nutrition Examination Survey

(NHANES), a national survey of the health status of the U.S. population, has determined blood lead levels for the U.S. population since

the early 1970s. In the 1970s, lead poisoning occurred increasingly

in children who did not live in dwellings with lead-based paint, 

suggesting that another source or sources of lead exposure were 

of even greater concern than lead paint. Research found that 

combustion of leaded gasoline was the primary source of lead in 

the environment. EPA promulgated two regulations: 

■ One required the availability of unleaded fuel for automobiles

designed to meet federal emission standards (e.g., catalytic 

converters) (EPA, 1973).

■ The second required a reduction of the lead content in leaded

gasoline (EPA, 1986).

Over the next decade, peak outdoor-air lead concentrations

decreased as a result of these controls. Exhibit 4-7 compares the

amount of lead used in gasoline production and the average blood

lead levels provided by the NHANES from 1976 to 1980. The

NHANES survey found a similar decline in children’s blood lead levels

(Exhibit 4-8). In 1991, a report from the National Academy of

Sciences predicted that declining ambient lead levels would reduce

the average blood lead level to less than 15 μg/dL. By the late

1990s, the average blood lead level in the U.S. for children was 

3 μg/dL (Schmidt, 1999). These data show a demonstrable effect

between regulatory actions to control lead and human exposure. 

Age-adjusted rates per 100,000 people

1976 1977

Year

1978 1979 1980

0

50

60

70

80

110

100

90

9

10

11

12

13

16

15

14

Total lead used per 6-month period (thousands of metric tons)

Average blood lead, micrograms per deciliter (μg/dL)

Lead used in gasoline

Average blood lead (μg/dL)

Exhibit 4-7: Lead used in gasoline production 

and average National Health and Nutrition Examination 

Survey (NHANES) blood lead, United States,

1976-1980

Source: National Research Council. Measuring Lead Exposures in Infants, 

Children and Other Sensitive Subpopulations. 1993.

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Exhibit 4-6: Blood lead levels considered elevated by the 

Centers for Disease Control and Prevention and the Public 

Health Service, 1970-1990

50

40

30

20

10

0

Source: CDC. Preventing Lead Poisoning in Young Children. 1991.

1970 1975 1980 1985 1990

Average blood lead micrograms per deciliter (μg/dL)
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.2 Health Status of the U.S. Compared to the Rest of the World 4-11

Elucidating Other Linkages

For all three case studies, the linkage between exposure and disease

is fairly strong. Subsequent sections of this chapter describe a

number of areas of concern regarding the potential human health

impacts of environmental exposure. The linkage in these areas ranges

from strong to weak. For example, in some cases outcome indicators

are available, but scientists are not yet sure how much of that

outcome is contributed by environmental factors. In other cases,

biomonitoring indicators are available, but scientists are not sure

whether the presence of a contaminant in the body at the levels

shown by the indicators causes adverse health effects. These areas

are discussed in this chapter, despite relatively weak linkages,

because the use of outcome and biomonitoring indicators is a

developing area. Understanding of linkages will be strengthened 

over time as more research is conducted to develop environmental

public health indicators and other data that reveal how pollutants

contribute to disease. 

4.2 Health Status of the

U.S. Compared to the

Rest of the World

Several measures are used worldwide to describe health status.

These indicators include life expectancy (i.e., the number of years

people can expect to live at birth), the number of infant deaths, and

the major causes of deaths. 

Collecting and reporting the data necessary to compare these

measures between nations is a challenge. Yet, as travel and

communications increasingly link the health of nations in the world,

the importance of having comparable information has increased.

Fortunately, considerable progress has been made to improve the

comparability of the necessary data among nations. 

In addition to enabling comparisons of health status, the data also

can be used to inform U.S. environmental health policy and 

programs, to focus research efforts, and to provide insights into 

linkages between environmental factors and health. 

Life Expectancy

Life expectancy is the average number of years at birth that a 

group of infants would live if throughout life they experienced the

age-specific death rates present at birth. In 2000, life expectancy at

birth for all people in the U.S. was a record 76.9 years (Pastor, et al.,

2002). In 1997, the U.S. ranked 19th in terms of life expectancy for

both females and males when compared with other countries

(Exhibit 4-9). Life expectancy at birth varies widely, both between

males and females and between nations. For both sexes, Japan

reports the highest life expectancy of all nations, with males 

expected to live 77.2 years and females expected to live 83.8 years.

Infant Mortality

Infant mortality is a particularly useful measure of health status

because it indicates both the current health status of the population

and predicts the health of the next generation (NCHS, 2001).

Between 1970 and 2000, the infant mortality rate in the U.S.

declined from 20.0 to 6.9 per 1,000 live births, the lowest ever

recorded in the U.S. (Pastor, et al., 2002; Mannino and Smith,

2001). When compared to other countries, the U.S. ranked 11th in

1960 with regard to infant mortality. In 1998, the U.S. ranked 28th

(Exhibit 4-10). 

Blood lead concentrations, micrograms per deciliter (μg/dL)

30

1976- 

1980

1988- 

1991

1992- 

1994

 1999-

2000

25

20

15

101,2

5

0

Exhibit 4-8: Concentration of lead in blood of children 

age 5 and under, 1976-1980, 1988-1991, 

1992-1994, 1999-2000

90th percentile (10 percent of 

children have this blood lead level 

or greater)

1

10 μg/dL of blood lead has been identified by CDC as elevated, which 

indicates the need for intervention. (CDC. Preventing Lead Poisoning in 

Young Children. 1991.)

2

Recent research suggests that blood levels less than 10 μg/dL may still 

produce subtle, subclinical health effects in children. (Schmidt, C.W. 

Poisoning Young Minds. 1999.)

Source: U.S. Environmental Protection Agency. America's Children and the 

Environment-Measures of Contaminants, Body Burdens, and Illnesses, Second 

Edition. February 2003. Data from CDC, National Center for Health 

Statistics, National Health and Nutrition Examination Survey, 1976-

2000.

Median value

(50 percent of children 

have this blood lead level 

or greater)
4-12 4.2 Health Status of the U.S. Compared to the Rest of the World Chapter 4 - Human Health

Leading Causes of Death

It is customary to measure the health of a nation by listing the leading causes of death. Comparisons of the 10 leading causes of death

in the U.S. and for the world demonstrate that infectious diseases

are a major contributor to deaths outside of the U.S. Four of the 10

leading causes of death in the world are infectious diseases

(Exhibit 4-11). These diseases account for 20.3 percent of the

deaths worldwide. Heart disease is the leading cause of death in the

U.S. as well as in the world. While heart disease accounts for nearly

one-third of the deaths in the U.S., it accounts for only 12.4 percent

of the deaths in the world. 

Cancer Morbidity and Mortality

The age-adjusted cancer mortality rates for all body sites except skin

are higher for males than females in all of the countries presented in

Exhibit 4-12. There is wide variation among men and women in ageadjusted cancer death rates. Hungary has the highest age-adjusted

total cancer (except skin) death rates for both males and females

(272.3 and 149.4 per 100,000 people, respectively). The U.S. ranks

16th for males, with an age-adjusted cancer death rate of 161.8 per

100,000, and 10th for females, with an age-adjusted cancer death

rate of 116.4 per 100,000. Sweden has the lowest age-adjusted 

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Males Females

55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87

Exhibit 4-9: Life expectancy at birth, according to sex, 

United States and selected countries, 1997

87 85 83 81 79 75 73 71 69 67 65 63 61 59 77

Russian Federation

Romania

Hungary

Bulgaria

Poland

Slovakia

Czech Republic

Puerto Rico

Portugal

United States

Ireland

Denmark

Germany

Costa Rica

Belgium

Austria

France

Finland

United Kingdom

Spain

New Zealand

Italy

Netherlands

Norway

Greece

Australia

Canada

Switzerland

Sweden

77.2 Japan

76.7

76.3

75.8

75.6

75.6

75.5

75.2

74.9

74.9

74.9

74.7

74.6

74.6

74.3

74.3

74.0

74.0

73.6

73.6

73.4

71.6

71.4

70.5

68.9

68.5

67.0

66.4

65.3

61.0

83.8

82.2

82.1

81.9

81.8

81.4

81.3

81.3

81.0

80.8

80.6

80.6

80.5

80.5

80.3

80.1

79.6

79.5

79.4

79.3

78.8

78.6

78.4

77.5

77.0

75.1

73.8

73.4

Russian Federation 73.0

Romania

Bulgaria

Hungary

Poland

Slovakia 76.7

Czech Republic

Denmark

Puerto Rico

Ireland

Portugal

United States

Costa Rica

United Kingdom

New Zealand

Germany

Netherlands

Finland

Belgium

Austria

Greece

Norway

Italy

Australia

Canada

Sweden

Spain

Switzerland

France

Japan

Note: Rankings are from highest to lowest life expectancy based on the latest data available for countries or geographic areas with at 

least 1 million people.

Source: Pastor, R.N., et al. Health. United States, 2002. 2002. 

57

Age in years
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.2 Health Status of the U.S. Compared to the Rest of the World 4-13

cancer death rate for males, and Greece has the lowest rate

for females (137.9 and 81.8 per 100,000, respectively)

(United Nations, 2001). 

The age-adjusted incidence of cancer for all sites except skin

varies widely among different countries (Exhibit 4-13).

Hungary reported the highest age-adjusted incidence of

cancers for males (405.4 per 100,000 people). New Zealand

had the highest age-adjusted cancer incidence rate for

females (303.2 per 100,000 people). The U.S. has the third

highest age-adjusted cancer incidence rates for both males

and females (361.4 and 283.2, respectively). Age-adjusted

cancer incidence rates are higher for males than females in

each of the countries presented in Exhibit 4-13 except

Denmark (GLOBOCAN 2000, 2001).

The varying incidence and mortality rates for cancer between

different countries could be due to many factors. Factors

related to the economic, social, cultural, psychological,

behavioral, and biological mechanisms that influence the

onset of cancer may contribute to these differences in rates

(NCI, 2002). A portion of these differences might also be

attributable to the varying prevalence of certain behavioral

risk factors for cancer—such as cigarette smoking, diet, and

alcohol consumption—within different countries. The

availability and use of certain drugs, such as anticancer and

immunosuppressive drugs, may also cause differences in the

rates of cancer among different countries. The extent to

which early diagnoses and treatment methods are available

and utilized could also account for some portion of the

variation in cancer rates among different countries, as could

variations in methods of classifying and reporting cancer. 

For more on morbidity, mortality, and age-adjusted rates, 

see Section 4.3.

Exhibit 4-10: Infant mortality rates per 1,000 live births, 

United States and selected countries, 1998*

0 5 15 20 10 25

20.5

16.4

14.4

12.6

10.9

10.5

9.7

9.5

9.4

8.8

7.2

7.1

6.2

5.9

5.7

5.7

5.7

5.7

5.6

5.6

5.5

5.5

5.3

5.3

5.2

5.2

5.0

4.9

4.8

4.7

4.6

4.6

4.2

4.1

4.0

3.6

3.5

3.2

Rate per 1,000 live births

Hong Kong

Sweden

Japan

Norway

Finland

Singapore

France

Germany

Denmark

Switzerland

Austria

Australia

Czech Republic

Netherlands

Canada

Italy

New Zealand

Scotland

Northern Ireland

Belgium

Spain

England and Wales

Israel

Greece

Portugal

Ireland

Cuba

United States

Slovakia

Kuwait

Poland

Hungary

Puerto Rico

Chile

Costa Rica

Bulgaria

Russia

Romania

* Data for Kuwait, Slovakia, and Spain are for 1996.

Source: Pastor, R.N., et al. Health. United States,2002. 2002. 
4-14 4.2 Health Status of the U.S. Compared to the Rest of the World Chapter 4 - Human Health

EPA’s Draft Report on the Environment 2003 ■ Technical Document

All causes

Heart disease

Stroke

Lower respiratory infections

Diarrheal diseases

Conditions arising during the perinatal period

Chronic obstructive pulmonary disease

Tuberculosis

Measles

Road traffic accidents

Trachea, bronchus and lung cancers

All other causes

Cause of Death

World (Including U.S.) (1990)

100.0

12.4

8.7

8.5

5.8

4.8

4.4

3.9

2.1

2.0

1.9

54.5

Percent of 

Total Deaths

50,467,000

6,260,000

4,381,000

4,299,000

2,946,000

2,443,000

2,211,000

1,960,000

1,058,000

999,000

945,000

27,502,000

Number 

of Deaths

Sources: World Resources Institute, et al. World Resources 1998-99. 1998; Anderson, R.N. Deaths: Leading Causes for 1999. 

2001. 

All causes

Heart disease

Cancer 

Stroke

Chronic lower respiratory diseases

Accidents (unintentional injuries)

Diabetes mellitus

Influenza and pneumonia

Alzheimer’s disease

Nephritis, nephritic syndrome, and nephrosis 

Septicemia

All other causes

United States (1999)

100.0

30.3

23.0

7.0

 5.2

 4.1

 2.9

 2.7

1.9

 1.5

 1.3

 20.2

2,391,399

725,192

549,838

167,366

124,181

97,860

68,399

63,730

44,536

35,525

30,680

484,092

Exhibit 4-11: Number of deaths and percent of total deaths for 10 leading causes of death, 

world (including U.S.), 1990, and United States, 1999
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.2 Health Status of the U.S. Compared to the Rest of the World 4-15

Greece

Japan

Spain

Portugal

Bulgaria

Romania

Finland

France

Italy

Russian Fed.

Australia

Switzerland

Sweden

Slovakia

Norway

Austria

Canada

Germany

Netherlands

Czech Republic

Ireland

United Kingdom

New Zealand

Denmark

Hungary

20 60 100 140 180 220 260 300

81.8

83.1

85

89.1

89.4

90

92.5

98

98.9

100.6

103.2

103.3

104

108.8

113.1

113.8

116.4

116.7

116.9

120

127.6

127.8

128.1

131.1

144

149.4

United States

Rate per 100,000 people

Exhibit 4-12: Age-adjusted cancer mortality rates for all sites except skin, by sex for selected countries, 2000

Source: United Nations. Demographic Yearbook, 1999. 2001. 

Sweden

Finland

Greece

Romania

Bulgaria

Australia

Norway

Portugal

Japan

Canada

United States

New Zealand

Austria

Ireland

Switzerland

United Kingdom

Spain

Italy

Germany

Netherlands

Denmark

France

Slovakia

Russian Federation

Czech Republic

Hungary

300 260 220 180 140 100 60

137.9

145.8

149.5

150

150.3

150.9

155.7

157.1

159.5

160.5

161.8

167.3

168.6

170.2

171

171

176.1

176.6

176.6

182

184.9

201.5

217.8

221.2

222.3

272.3

Males Females
EPA’s Draft Report on the Environment 2003 ■ Technical Document

4-16 4.2 Health Status of the U.S. Compared to the Rest of the World Chapter 4 - Human Health

Greece

Spain

Japan

Bulgaria

Romania

Portugal

Russian Fed.

Slovakia

Switzerland

Italy

Austria

France

Finland

United Kingdom

Germany

Ireland

Czech Republic

Norway

Sweden

Netherlands

Canada

Hungary

Australia

Denmark

New Zealand

100 150 200 250 300 350 400 450

158

166.3

170.5

180.4

185.8

192.8

193.5

204.3

211.3

217.8

219.6

220.3

222.6

234.3

235.3

237.1

242.6

249.8

250.1

253.4

266

275.9

279.3

283.2

296.9

303.2

Incidence rate per 100,000 people

Males Females

Romania

Greece

Bulgaria

United Kingdom

Sweden

Portugal

Ireland

Spain

Japan

Denmark

Austria

Switzerland

Norway

Italy

Netherlands

Russian Federation

Germany

Slovakia

Canada

Czech Republic

France

Australia

Finland

New Zealand

Hungary

450 350 400 300 250 200 150 100

224

225.1

232.3

260.3

262

270.3

272.1

272.3

275.5

278.7

281.9

283.4

287.2

290.5

299.6

299.7

312.3

318.3

323.4

335.2

342.6

355.3

359.3

361.4

375.3

405.4

Exhibit 4-13: Age-adjusted cancer incidence rates for all sites except skin, by sex for selected countries, 2000

Source: GLOBOCAN. Cancer Incidence, Mortality, and Prevalence Worldwide, Version 1.0. 2001; International Agency for Research on Cancer. IARC Cancer Base No. 5. 2001.

United States United States
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-17

4.3 Health Status of the

U.S.: Indicators and Trends

of Health and Disease

This section identifies key indicators of health outcomes (mortality

and disease) in the U.S. and describes trends for these outcomes.

These outcomes are featured in this report because they are 

important measures of the health of people in the U.S., and/or

because environmental exposure does or may play a role in 

contributing to the outcome.

The case study on air pollution, presented earlier in Section 4.1,

provides an example of how health outcome data can be used to 

elucidate the linkage between pollution exposure and health 

outcomes. In this case study, a comparison between mortality rates

and air monitoring data revealed an association between deaths and

peak air pollutant concentrations. 

Mortality

Overall mortality is a key measure of health in a population. There 

were more than 2,391,399 deaths in the U.S. in 1999 (Anderson,

2001), a number much larger than the 1,989,841 recorded in 1980.

The increase in the number of deaths reflects the increase in the size

and the aging of the U.S. population. The age-adjusted death rate for

all causes has declined steadily since 1950, from 1,446 per 100,000

people to 876 in 1998. The age-adjusted death rates are higher for

men than for women, a relationship that has not changed over the

years. Heart disease, cancer, and stroke are the three leading causes of

death, accounting for about 60 percent of all deaths. 

This section presents trends in life expectancy and in mortality 

due to cancer, cardiovascular disease, chronic obstructive pulmonary

disease, and asthma. It also presents trends in mortality for children,

including infant mortality and mortality due to cancer, asthma, and

birth defects. 

Unless otherwise noted, the death statistics are based on the

underlying cause of death and are compiled from death certificates. 

The underlying cause of death is the disease or injury that is judged to

have initiated the events that led to death. The mortality rate is the

proportion of the population that dies of a disease. The rate is usually

calculated for a calendar year, is often expressed per 100,000

population, and is called the crude death rate.

Morbidity

Morbidity is another measure of health for a population. Morbidity

data are often described by using the incidence and prevalence of a

disease or condition:

■ Incidence refers to the number of new cases of a disease or condition in a given time period in a specified population. 

■ Prevalence refers to the total number of persons with a given 

disease or condition in a specified population in a particular 

time period. 

This section provides information on trends for several diseases,

including cancer, cardiovascular disease, asthma, and gastrointestinal

illness. It also examines trends in children’s environmentally related

diseases, including cancer and asthma as well as low birthweight and

the incidence of birth defects. 

Comparison Across Time, Populations, and Geographic

Areas

Incidence, prevalence, and mortality statistics may be used to

compare the rates of disease at two or more points in time or across

different populations or between different geographic areas. These

comparisons are particularly useful to determine whether the

populations differ by some factor (often called a risk factor) that 

is known or suspected of affecting the risk of developing the disease

or condition. For example, different populations that are compared

can be countries, workers in factories, or states. 

In general, disease incidence, prevalence, and mortality increase with

age. For this reason, when comparing different populations, the data

must often be adjusted to account for the age differences between

the populations. The adjusted data, called “age-adjusted rates,” are

used when appropriate in this chapter. 

Perceived Well-Being

Another measure of health, perceived well-being, is discussed briefly

here, but is not covered by an indicator. The reporting of health as

excellent, very good, good, fair, or poor captures both the physical

health of the individual and the emotional aspects of well-being

(Kramarow, et al., 1999). In 1999, approximately 90 percent of the

population of the U.S. reported that they were in good, very good,

or excellent health (Eberhardt, et al., 2001), a slight increase from

89.6 percent in 1991. As might be expected, the percentage of 

people reporting good-to-excellent health decreases with age. While

95 percent of those 18 to 44 years of age reported good-toexcellent health, only 77 percent of persons 65 years of age and

older reported that they were in good-to-excellent health. Also, 

non-Hispanic African Americans and Hispanics of all ages reported

worse health than non-Hispanic Whites (Eberhardt, et al., 2001). 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

The primary source for data on life expectancy in the U.S. is

the National Center for Health Statistics (NCHS). Through its

National Vital Statistics System, the NCHS has collected and

published data on births, deaths, marriages, and divorces in the

U.S. since 1933. U.S. data are for the 50 states and the

District of Columbia, unless otherwise specified. Virtually all

births and deaths are registered. U.S. Standard Certificates of

Live Birth and Death are revised periodically, usually every 10

to 15 years. New versions of the U.S. Standard Certificates of

Live Birth and Death are planned for 2003. Most state

certificates conform closely in content and arrangement to the

standard certificate recommended by NCHS, and all certificates

contain a minimum data set specified by NCHS. At the time of

birth, the mother provides demographic information on the

birth certificate, such as race and ethnicity. Medical and health

information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A

physician, medical examiner, or coroner provides medical

certification of cause of death. 

What the Data Show

Throughout the 20th century there has been a general

improvement in life expectancy at birth in the U.S. (Hoyert, et al.,

2001). In 2000, life expectancy at birth reached a record high of

76.9 years, based on preliminary data. In 1999, life expectancy

was 76.7 years (Pastor, et al., 2002). This follows 5 consecutive

years of improvement and a general upward trend in life

expectancy throughout the 20th century. 

The gap in life expectancy between males and females widened

from 2.0 years to 7.8 years between 1900 and the late 1970s.

Now this gap is narrowing, and in 2000 the difference in life

expectancy between the sexes was 5.4 years. This improvement

was primarily due to a greater reduction in mortality for males

from heart disease, cancer, suicide, and homicide. Between 1970

and 1999, life expectancy at birth in the U.S. increased from 67.1

to 73.9 years for males and from 74.7 to 79.4 years for females

(Pastor, et al., 2002; Mannino and Smith, 2001).

In 1999, life expectancy at birth for the African American

population reached a record high of 71.4 years. In 2000, the

difference in life expectancy between the African American and

White populations was 5.6 years, based on preliminary data.

Based on 1999 data, White females continue to have the highest

life expectancy (79.9 years), followed by African American females

(74.7 years), White males (74.6 years), and African American

males (67.8 years). The narrowing of the gap in life expectancy

between Whites and African Americans was largely due to a

greater reduction in mortality for African Americans due to

homicide, cancer, stroke, and HIV-related disease.

Data Source 

National Vital Statistics System, National Center for Health

Statistics. (See Appendix B, page B-25, for information.)

Indicator Life expectancy – Category 1

4-18 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

This section addresses five questions: 

■ What are the trends for life expectancy? (Section 4.3.1)

■ What are the trends for cancer, cardiovascular disease, chronic

obstructive pulmonary disease, and asthma? (Section 4.3.2)

■ What are the trends for gastrointestinal illness? (Section 4.3.3)

■ What are the trends for children’s environmental health issues?

(4.3.4) 

■ What are the trends for emerging health effects? (Section 4.3.5)

4.3.1 What are the trends for life

expectancy?

Life expectancy is the average number of years at birth that a group

of infants would live if throughout life they experienced the age-specific death rates present at birth. 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-19

The term “cancer” is used to characterize diseases in which abnormal cells divide without control. A cancerous cell loses its ability

to regulate its own growth, control cell division, and communicate

with other cells. Cancer cells can invade nearby tissues and can

spread through the bloodstream and lymphatic system to other

parts of the body (NCI, 2003).

What the Data Show

In the U.S., 549,838 people died of cancer in 1999. The death

rate was 201.6 per 100,000 people. Cancer accounted for 23

percent of all deaths (Anderson, 2001). Between 1990 and 1998,

the age-adjusted death rates for all types of cancer for all persons

declined from 173.3 to 161.5 per 100,000 people. The death

rate for cancer is highest for non-Hispanic Whites (232.8 per

100,000 people). The death rate for cancer for non-Hispanic

African Americans is 185.6 per 100,000 and for Hispanics is 64.6

per 100,000 (Hoyert, et al., 2001). Death rates for different

types of cancer show differences across age, gender, and ethnic

lines.

Over the past century, the age-adjusted incidence rate for all cancers for all persons decreased from 400.3 per 100,000 people to

395.3. Age-adjusted incidence rates have not declined uniformly

over all types of cancer. For example, the incidence of lung cancer

for men was 69.8 per 100,000 in 1998, a decline from 81.8 in

1990 and from 76.2 in 1975. For women, the 1998 age-adjusted

lung cancer incidence rate of 43.4 per 100,000 people was an

increase from 41.6 in 1990 and was nearly 2 times the 1975 rate

of 21.5 (Ries, et al., 2001). 

Exhibit 4-14 shows the estimated percent change in death and

incidence rates according to the type of cancer for men and

women of all races, between 1973 and 1998. Notable is the 150.6

percent increase in lung cancer deaths for females between 1973

and 1998. Despite the progress in reducing the number of new

cases of some types of cancer, the incidence rates for all types of

cancers combined increased 22.4 percent (Ries, et al., 2001).

Data Sources

Mortality: National Vital Statistics System, National Center 

for Health Statistics. (See Appendix B, page B-25 for 

more information.)

Incidence: National Notifiable Diseases Surveillance 

System, Centers for Disease Control and Prevention. 

(See Appendix B, page B-25 for more information.)

Indicators Cancer mortality – Category 1

Cancer incidence – Category 2 

4.3.2 What are the trends for

cancer, cardiovascular disease,

chronic obstructive pulmonary

disease, and asthma?

Several chronic diseases that are important indicators of health are

presented in this section. Cardiovascular disease, cancer, and stroke

are the three leading causes of death in the U.S., accounting for

60.3 percent of all deaths (Anderson, 2001). Chronic obstructive

pulmonary disease, a category of diseases that restrict airflow

through parts of the respiratory system, was the fourth leading cause

of death in the U.S. in 1999 (Hoyert, et al., 2001). Asthma, a chronic condition characterized by inflammation of the airways and lungs,

affected more than 10 million people in the U.S. in 1999 (Mannino,

et al., 2002).
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Indicators Cancer mortality – Category 1 (continued)

Cancer incidence – Category 2 (continued)

4-20 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

NOS = Not otherwise specified

ONS = Other nervous system

Source: Ries, L.A.G., et al. Surveillance, Epidemiology and End Results (SEER) Cancer Statistics Review, 1973-1998. 2001.

Exhibit 4-14: Trends in United States cancer mortality rates and Surveillance, Epidemiology and End Results (SEER) 

 incidence (annual percentage change 1973–1998)

Percent change, 1973-1998

Mortality

-200 -150 -100 -50

150.6

56.1

45.2

35.8

32.7

20.4

17.5

10.3

4.4

1.6

0.0

-3.2

-9.0

-10.0

-13.0

-14.2

-14.7

-20.9

-24.1

-25.8

-28.1

-31.4

-45.2

-49.8

-66.5

-69.3

0 50 100 150 200

Lung (females)

Liver & intrahep

Non-Hodgkin's

Melanomas of skin

Multiple myeloma

Esophagus

Kidney/renal

Brain & ONS

Lung (males)

Prostate

All cancers

Pancreas

Leukemia

All except lung

Ovary

Breast (females)

Larynx

Thyroid

Urinary bladder

Colon/rectum

Corpus & uterus, NOS

Oral cav & pharynx

Stomach

Cervix uteri

Hodgkin's

Testis

Percent change, 1973-1998

Incidence

-200 -150 -100 -50

149.3

129.9

116.3

94.0

82.6

56.3

54.9

46.7

32.3

22.4

21.6

19.0

17.6

12.4

10.1

-1.1

-4.8

-5.9

-6.7

-9.5

-14.7

-16.4

-23.0

-26.3

-34.0

-43.7

0 50 100 150 200

Melanomas of skin

Lung (females)

Prostate

Liver & intrahep

Non-Hodgkin's

Testis

Thyroid

Kidney/renal

Breast (females)

All cancers

All except lung

Multiple myeloma

Brain & ONS

Esophagus

Urinary bladder

Ovary

Lung (males)

Colon/rectum

Leukemias

Pancreas

Oral cav & pharynx

Hodgkin's

Larynx

Corpus & uterus, NOS

Stomach

Cervix uteri
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-21

The broad category of cardiovascular disease (CVD) includes any

disease involving the heart and blood vessels. Coronary heart

disease (CHD) and cerebrovascular disease, commonly known as

stroke, are the major cardiovascular diseases. 

What the Data Show

Because there are several conditions included in the

cardiovascular disease category, it is not surprising that the

National Heart, Lung, and Blood Institute (NHLBI) estimates that

approximately 59.7 million people in the U.S. have some form of

CVD (NHLBI, 2000). An estimated 12.2 million people have

coronary heart disease and 4.4 million have had a stroke.

CVD is the leading cause of death for both men and women in the

U.S. (AHA, 2001). The age-adjusted death rate for CVD reached

a peak in 1950. Between 1950 and 1999, the age-adjusted death

rate for CVD declined 60 percent (Exhibit 4-15) (CDC, 1999a).

The percentage of all deaths due to CVD increases with age, from

19 percent at 35 to 44 years of age, to 53 percent for people 85

years and older.

The prevalence of cardiovascular disease varies depending upon

the age and sex of the individual (Exhibit 4-16). CVD is more

prevalent in men than in women until 65 years of age, when the

prevalence among women equals that in men. After age 74

years, the prevalence is greater in women than in men. The ageadjusted prevalence of CVD in adults for non-Hispanic Whites

is 30.0 percent for men and 23.8 percent for women; for nonHispanic African Americans it is 40.5 percent for men and 39.6

percent for women.

The death rate for CHD was 195.6 per 100,000 people in 1999

(AHA, 2001). The death rates were lower for White men (249.4

per 100,000 people) than for African American men (272.6) and

higher for African American women (192.5) than for White women

(152.5) (AHA, 2001). 

After age 45, the prevalence of CHD is lower for women than for

men at all ages and increases with age for both men and women,

peaking after 75 years of age (Exhibit 4-17). The age-adjusted

prevalence for CHD for non-Hispanic Whites is 6.9 percent for

men and 5.4 percent for women. For non-Hispanic African

Americans, the prevalence is 7.1 percent for men and 9.0 percent

for women (AHA, 2001).

Indicators Cardiovascular disease mortality – Category 1 

Cardiovascular disease prevalence – Category 1 

Death rate per 100,000 people500

400

300

200

100

1900 1920 1940 1960 1980 1996

0

Total cardiovascular disease

Coronary heart disease

Stroke

Exhibit 4-15: Death rates for total cardiovascular disease, 

coronary heart disease, and stroke, by year, United States, 

1900-1996

Notes: Rates are per 100,00 people, age adjusted to the 1940 U.S. population.

Diseases are classified according to International Classification of Diseases (ICD) 

codes in use when the deaths were reported. 

Source: CDC. Decline in Deaths from Heart Disease and Stroke, United States, 1900-

1999. 1999.

Year

Exhibit 4-16: Prevalence of cardiovascular diseases among 

adults by age and sex, United States, 1988-1994

Percentage of population

80

70

60

50

40

30

20

10

0

20-24 25-34 35-44 45-54 55-64 65-74 75+

Ages

Source: American Heart Association. 2001 Heart and Stroke Statistical Update. 

2001. Data from NHANES III, 1988-1994, the CDC, National Center for Health 

Statistics, and the American Heart Association.

Males

Females
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Stroke ranks as the third leading cause of death in the U.S. Stroke

accounted for 7.0 percent of total deaths. The death rate for

stroke was 61.4 deaths per 100,000 people. The age-adjusted

prevalence of stroke is higher for men than for women at all ages.

In 1999, there were 167,366 deaths (102,881 were females)

attributed to stroke (Anderson, 2001). Death rates for stroke

were highest among non-Hispanic Whites (70.8 per 100,000

people), followed by non-Hispanic African Americans (56.6) 

and Hispanics (18.8).

Data Sources

Mortality: National Vital Statistics System, National Center 

for Health Statistics. (See Appendix B, page B-26 for 

more information.)

Prevalence: NHANES III (1988-1994), National Center 

for Health Statistics. (See Appendix B, page B-26, for 

more information.) 

4-22 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Exhibit 4-17: Prevalence of coronary heart disease 

by age and sex, United States, 1988-1994

Percentage of population

20

0

5

10

15

35-44 45-54 55-64 65-74 75+

Ages

Source: American Heart Association. 2001 Heart and Stroke Statistical Update. 2001. 

Data from NHANES III, 1988-1994, the CDC, National Center for Health Statistics, 

and the American Heart Association.

Males

Females

Indicators Cardiovascular disease mortality – Category 1 (continued) 

Cardiovascular disease prevalence – Category 1 (continued) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-23

Indicator Indicator Chronic obstructive pulmonary disease mortality – Category 1 

Chronic obstructive pulmonary disease (COPD), sometimes

referred to as chronic lung disease, is a disease that damages lung

tissue or restricts airflow through the bronchioles and bronchi

(ALA, 2001). Chronic bronchitis and emphysema are the most

frequently occurring COPDs.

What the Data Show

In 1999, COPD was the fourth leading cause of death, accounting

for more than 124,181 deaths (5.2 percent of total deaths)

(Hoyert, et al., 2001). The age-adjusted death, rate for COPD

was 45.8 per 100,000 population. From 1980 to 1998, the ageadjusted death rates for COPD increased from 28.3 to 42.0 per

100,000 population for men and women of all racial and ethnic

groups in the U.S. (Eberhardt, et al., 2001). For females, the ageadjusted death rates for COPD increased steadily from 1980 to

1998, from 14.9 per 100,000 population to 34.8 in 1998

(Exhibit 4-18). For males, the age-adjusted death rates rose 

between 1980 and 1985 from 49.9 to 56.2 per 100,000. From

1990 to 1998, the rate remained generally stable, declining

slightly in 1998 to 54.0 per 100,000.

In 1998, the age-adjusted death rate for COPD was highest for

White males at 55.4 per 100,000 population, followed by African

American males (45.2) and Hispanic males (26.2 per 100,000

population). Among females, White females had the highest rates

(36.5) followed by African American females (22.3) and Hispanic

females (13.7 per 100,000 population) (Hoyert, et al., 2001).

Data Source 

National Vital Statistics System, National Center for Health

Statistics. (See Appendix B, page B-26, for more information.) 

Deaths per 100,000 people

60

50

40

30

10

20

1980 1985 1990 1995 1996 1998 1997

0

Source: Eberhardt, M.S., et al. Health, United States, 2001 with Urban and Rural Health 

Chartbook. 2001.

Exhibit 4-18: Age-adjusted death rates for chronic 

obstructive pulmonary disease according to sex, 

selected years, in the United States 1980-1998

Males

Both males 

and females

Females

Year
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Asthma is a chronic respiratory disease characterized by inflammation of the airways and lungs. During an asthma attack the airways

that carry air to the lungs are constricted, and as a result less air

is able to flow in and out of the lungs (NCHS, 2001). Asthma

attacks can cause a multitude of symptoms ranging in severity

from mild to life-threatening. These symptoms include wheezing,

breathlessness, chest tightness, and coughing (NCHS, 2001).

What the Data Show

In 1999, 4,657 people died from asthma. The age-adjusted death

rate was 17.2 per 1,000,000 population. Exhibit 4-19 shows the

trends in age-adjusted death rates with asthma as the underlying

cause of death. 

In 1999, approximately 10.5 million people in the U.S. reported

that they had an asthma attack or episode in the preceding 12

months (Mannino, et al., 2002). This included approximately 7.3

million people over 14 years of age. The 1999 age-adjusted

prevalence of asthma for people of all ages was 38.4 per 100,000

population in 1999 (Exhibit 4-20). That same year, the prevalence of asthma in adults was highest (42.2 per 100,000) for

people 15 to 34 years of age, and lowest (22.1 per 100,000) for

those 65 years of age and older. African Americans were more

likely to report an asthma episode or attack than other race/ethnic groups, and females were more likely than males to have had

an asthma episode or attack. Since 1997, the age-adjusted prevalence of asthma has decreased slightly from 40.7 per 100,000

population to 38.4 per 100,000. Changes in the way asthma data

are collected were made in 1997, limiting the ability to compare

current data with earlier reports.

There are regional differences in the prevalence of asthma with the

highest prevalence in the Northeast (61.8 per 1,000 people)

(Adams, et al., 1999). The prevalence in the Midwest was 56.6 per

1,000 people. The prevalence in the South (51.8 per 1,000) was

similar to the prevalence in the West (52.9 per 1,000). People who

lived in a central city reported a higher number of cases (61.7 per

1,000 people) than those who did not live in the central city (54.9

per 1,000). Those who did not live in a Metropolitan Statistical Area

(an urbanized area with at least 50,000 inhabitants) had the lowest

prevalence, 46.9 per 1,000 people.

Data Sources 

Mortality: National Vital Statistics System, National Center 

for Health Statistics. (See Appendix B, page B-27 for 

more information.)

Prevalence: National Health Interview Survey, Centers for 

Disease Control and Prevention. (See Appendix B, page B-27, 

for more information.) 

Indicators Asthma mortality – Category 1 

Asthma prevalence – Category 1 

4-24 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Exhibit 4-19: Annual rate* of deaths with asthma as the underlying cause of death diagnosis, by race, sex, and age group, 

United States, 1980-1999

Race

 White

 Black 

 Other 

Sex

 Male

 Female

Age Group (years)

 0-4

 5-14

 14-34

 35-64

 65+ 

Total**

12.9

27.6

13.5

14.7

14.4

1.8

1.9

3.0

14.0

61.8

14.4

15.6

34.8

16.9

15.9

19.2

1.5

2.9

4.2

17.7

72.5

17.7

17.5

40.9

23.6

17.8

22.1

2.0

3.2

5.0

18.8

87.0

20.2

18.8

46.2

23.3

 17.9

25.1

1.8

4.0

6.7

20.6

90.8

21.9

18.1

48.0

27.6

17.7

25.0

2.3

4.6

6.5

20.3

90.3

21.8

17.4

42.5

26.6

16.6

23.7

1.9

3.4

6.1

19.0

86.7

20.6

17.0

44.7

22.7

16.5

23.3

2.1

3.8

6.4

17.8

86.9

20.3

14.2

38.7

20.4

13.1

20.4

1.7

3.6

5.9

15.8

69.9

17.2

1980 1985 1990 1995 1996 1997 1998 1999

* Per 1,000,000 population. ** Age adjusted to the 2000 U.S. population. 

Source: Mannino, D.M., et al. Surveillance for Athma - United States, 1980-1999. 2002.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-25

31.4

33.1

19.9

30.5

31.9

23.0

45.1

30.0

29.9

31.9

31.4

37.0

38.6

12.8

33.8

38.9

36.7

50.9

36.1

30.8

38.6

38.6

41.5

45.8

40.2

39.1

44.2

44.0

63.7

37.3

38.4

36.3

41.9

54.5

64.8

44.4

48.6

61.1

60.5

82.0

57.8

50.1

39.4

55.2

53.6

65.6

43.2

43.0

65.6

40.1

69.8

67.2

46.2

45.5

54.6

40.5

45.4

34.7

33.0

47.9

41.2

60.0

44.2

37.0

27.3

40.7

37.5

46.7

33.7

31.7

44.4

46.4

57.8

37.5

35.7

28.7

39.2

37.6

42.7

38.9

31.6

44.5

42.1

56.4

42.2

33.4

22.1

38.4

White

Black

Other

Male

Female

0-4

5-14

15-34

35-64

65+

Total

Data are per 100,000 population, per year.

Source: Mannino, D.M., et al. Surveillance for Asthma - United States,1980-1999. 2002.

Self-Reported Asthma Prevalence 

During the Preceding 12 Months

Episode of Asthma or Asthma Attack 

During the Preceding 12 Months

Race

Sex

1980 1985 1996 1990 1999 1995 1997 1998

Exhibit 4-20: Estimated annual prevalence of self-reported asthma (1980-1996) or an episode of asthma attack (1997-1999) 

during the preceding 12 months, by race, sex, and age group, United States, 1980-1999

Age Group (years)

4.3.3 What are the trends for

gastrointestinal illness?

The human gastrointestinal tract includes the stomach, the large

intestine, and the small intestine. Gastrointestinal infections and

illnesses are caused by several types of microorganisms—that is,

bacteria, protozoa, fungi, and viruses. Food and water contaminated

with pathogenic microorganisms are the major environmental source

of gastrointestinal illness. A system for reporting food- and

waterborne disease outbreaks has been in place for many years in

the U.S. This system enables public health officials to investigate and

determine the role of food and water in contributing to intestinal

illness, and identify actions that may be needed to protect public

health. For example, the system tracks the number of waterborne

disease outbreaks reported voluntarily by state, territorial, and local

public health officials (See box, “Waterborne Disease Outbreaks

Associated with Drinking Water 1971-2000”). These data should be

interpreted with caution, however, because many factors can

influence whether a waterborne disease outbreak is recognized,

investigated, and reported. Changes in the number of outbreaks

reported could reflect actual changes or simply changes in

surveillance and reporting. (For additional information on waterborne

disease, see Chapter 2, Purer Water.)

The number of deaths from microorganism-induced gastrointestinal

illnesses recently increased in the U.S., after decades of relatively

stable death rates (Peterson and Calderon, 2003). The increases

were particularly dramatic in young children (less than 6 years of

age) and older Americans (more than 65 years of age). Many 

milder cases of gastrointestinal illnesses go unreported or are not

diagnosed, making it difficult to estimate the number of people

affected every year. Often, symptoms are not serious enough to 

warrant a visit to a doctor or hospital, which further contributes to

the underestimation of gastrointestinal illness.

Seven notifiable gastrointestinal diseases caused by microorganisms

have been chosen as indicators for this report: cholera,

cryptosporidiosis, Escherichia coli O157 : H7, Hepatitis A,

salmonellosis, shigellosis, and typhoid fever. The reporting period

Indicators Asthma mortality – Category 1 (continued)

Asthma prevalence – Category 1 (continued)
EPA’s Draft Report on the Environment 2003 ■ Technical Document

4-26 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

includes five years 1997-2001. These include two diseases—cholera

and typhoid fever—that are rarely identified in this country. These

diseases are nevertheless included because they can be severe

illnesses and a sudden increase in their reporting would signal a

public health emergency for which prompt action would be needed.

In addition to the seven diseases discussed here, a number of other

gastrointestinal diseases are caused by microorganisms. These

include giardiasis, caused by the pathogen Giardia. Giardiasis has

become notifiable only as recently as 2002 (CDC, 2003), so no

indicator is available at this time. 

The primary means of transmission for the seven diseases reported

here is oral-fecal. The disease microbes shed in the feces of infected

individuals and then can be transmitted to humans through food,

water, person-to-person contact, or contact with ill animals. The

seven diseases are cholera, cryptosporidiosis, E. coli O157:H7,

Hepatitis A, salmonellosis, shigellosis, and typhoid fever. Exhibit 4-22

shows the incidence of each for 1997 through 2001. 

Waterborne Disease Outbreaks Associated with Drinking Water 1971-2000

Since 1971, the Centers for Disease Control and Prevention (CDC), EPA, and the Council of State and Territorial Epidemiologists have

maintained a collaborative surveillance system for the occurrences and causes of waterborne-disease outbreaks (WBDO). These data are only

a small part of the larger body of information related to drinking water quality in the United States. State, territorial, and local public health

agencies are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC. These data are used to

identify types of water systems, their deficiencies, the etiologic agents (e.g., microorganisms and chemicals) associated with outbreaks, and to

evaluate current technologies for providing safe drinking water and safe recreational waters. This system reports outbreaks and estimated

numbers of people who become ill. It does not provide information on non-outbreak related or endemic levels of waterborne illness.

Moreover, the focus is on acute illness. The system does not address chronic illnesses such as cancer, reproductive, or developmental effects.

CDC and EPA are collaborating on a series of epidemiology studies to assess the magnitude of non-outbreak waterborne illness associated

with consumption of municipal drinking water.

Between 1971 and 2000, there were 751 reported waterborne disease outbreaks associated with drinking water from individual, non-community systems, and community water systems (Exhibit 4-21). During 1999-2000, a total of 44 outbreaks (18 from private wells, 14 from noncommunity systems, and 12 from community systems) associated with drinking water were reported by 25 states (Craun and Calderon, 2003).

However, these data should be interpreted with caution. Many factors can influence whether a WBDO is recognized and investigated by

local, territorial, and state public health agencies. For example, the size of the outbreak, severity of the disease caused by the outbreak,

public awareness of the outbreak, whether people seek medical care or report to a local health authority, reporting requirements, routine

laboratory testing for organisms, and resources for investigation can all influence the identification and investigation of a WBDO. 

This system underreports the true number of outbreaks because of the multiple steps required before an outbreak is identified and

investigated. Thus, an increase in the number of outbreaks reported could either reflect an actual increase or improved surveillance 

and reporting at the local and state level.

0

10

20

30

40

50

60

Exhibit 4-21: Number of reported waterborne disease outbreaks associated 

with drinking water by year and type of water system, United States, 1971-2000 (n=751)

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2000

Number of outbreaks

Non-community

Individual

Community

Type of Water System*

*Non-community water systems are systems that either (1) regularly supply water to at least 25 of the same people at least 6 months per year, but not year round (e.g., 

schools, factories, office buildings, and hospitals that have their own water systems), or (2) provide water in a place where people do not remain for long periods of time (e.g., 

a gas station or campground).

Individual water systems are not regulated by the Safe Drinking Water Act and serve fewer than 25 persons or 15 service connections, including many private wells.

Community water systems provide water to at least 25 of the same people or service connections year round.

Source: Based on data presented in Craun, G.F. and R.L. Calderon. Waterborne Outbreaks in the United States,1971-2000. 2003.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-27

The data source for these seven indicators is the Centers for Disease

Control and Prevention, Epidemiology Program Office, National

Notifiable Diseases Surveillance System. This system provides weekly

provisional information from the Council of State and Territorial

Epidemiologists (CSTE) on the occurrence of diseases defined as

notifiable. A notifiable disease is one that, when diagnosed, health

providers report to state or local public health officials. Notifiable

diseases are of public interest because of their contagiousness,

severity, or frequency (Pastor, et al., 2002). State epidemiologists

report cases of notifiable diseases to CDC, and CDC tabulates and

publishes these data in Morbidity and Mortality Weekly Report

(MMWR) and Summary of Notifiable Diseases, United States. Policies

for reporting notifiable disease cases can vary by disease or reporting jurisdiction. CSTE and CDC annually review and recommend

additions or deletions to the list of nationally notifiable diseases

based on the need to respond to emerging priorities. Reporting

nationally notifiable diseases to CDC, however, is voluntary. Reporting is

currently mandated by law or regulation only at the local and state

level. Therefore, the list of diseases that are considered notifiable

varies slightly by state. 

Notifiable disease data are useful for analyzing disease trends and

determining relative disease burdens. These data, however, must be

interpreted in light of reporting practices. The degree of

completeness of data reporting is influenced by many factors such as

the diagnostic facilities available; the control measures in effect;

public awareness of a specific disease; and the interests, resources,

and priorities of state and local officials responsible for disease

control and public health surveillance. Finally, factors such as

changes in case definitions for public health surveillance,

introduction of new diagnostic tests, or discovery of new disease

entities can cause changes in disease reporting that are independent

of the true incidence of disease.

Exhibit 4-22: Prevalence of reported gastrointestinal diseases, United States, 1997-2001

1

10

100

1,000

10,000

100,000

Cholera Cryptosporidiosis E.coli O157:H7 Hepatitis A

Disease

Salmonellosis Shigellosis Typhoid fever

Reported cases

1997 1998 1999

2000 2001

Sources: CDC. Notice to Readers: Final 2001 Reports of Notifiable Diseases. 2002; CDC. Notice to Readers: Final 2000 Reports of Notifiable Diseases. 2001; CDC. Notice to Readers: 

Final 1999 Reports of Notifiable Diseases. 2000: CDC. Notice to Readers: Final 1998 Reports of Notifiable Diseases. 1999; CDC. Notice to Readers: Final 1997 Reports of Notifiable 

Diseases. 1998.
Cholera is a diarrhea illness caused by infection of the intestine

with the bacterium Vibrio cholerae. Infections can often be mild or

without symptoms, but can sometimes be severe, and even fatal.

Approximately 1 in 20 infected persons has severe disease 

characterized by severe, watery diarrhea that can lead to dehydration and shock. Without treatment, death can occur within hours

(ICTDRN, 2002). 

What the Data Show

Very few cases of cholera are reported on an annual basis in the

U.S. It is believed most cases are associated with consumption of

contaminated seafood or with international travel to areas where

cholera is endemic (e.g., South America) (CDC, 2001a).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-27, for

more information.) 

Indicator Infectious disease prevalence – Cholera – Category 2

Cryptosporidiosis is an illness resulting from infection of the

gastrointestinal tract with Cryptosporidium parvum and other

species of Cryptosporidium. This pathogen is excreted by humans,

as well as wild and domestic animals, including farm animals; it

contaminates water sources via animal feces or domestic sewage.

Runoff from agricultural operations into drinking water sources has

been one cause of cryptosporidiosis outbreaks (Franzen and

Muller, 1999).

Severe diarrhea is the most common symptom. Additional

symptoms include gastric pain, fever, nausea, and fatigue

(Guerrant, 1997). There is no antibiotic that is effective for

treatment of cryptosporidiosis. As a result, a healthy immune

system is important in limiting an individual’s response to

Cryptosporidium parvum infection. Cryptosporidiosis can be deadly

when contracted by immunocompromised individuals. In extreme

cases of cryptosporidiosis, infection can spread beyond the

gastrointestinal tract to the gall bladder and biliary tract. 

What the Data Show

The occurrence of symptoms or conditions associated with 

cryptosporidiosis are likely underreported. “We do not know

exactly how many cases of cryptosporidiosis actually occur. Many

people do not seek medical attention or are not tested for this

parasite and so Cryptosporidium often goes undetected as the

cause of intestinal illness” (CDC, 1998b).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-28, 

for more information.) 

Indicator Infectious disease prevalence – Cryptosporidiosis – Category 2 

4-28 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-29

E. coli O157:H7 is one of over 170 strains and many hundred 

sub-strains of the bacterium Escherichia coli. Most strains are

harmless and live in the intestines of healthy humans and animals;

this strain can cause severe illness. E. coli O157:H7 is not a

disease itself, but rather a cause of illness. The identifier in the

name of the bacterium refers to the specific antigenic markers

found on its cell wall and distinguishes it from other types of E.

coli. Infection often leads to bloody diarrhea and occasionally to

kidney failure, particularly in young children (CDC, 2001b). A

1982 outbreak of severe bloody diarrhea was traced to

contaminated hamburgers.

What the Data Show

CDC estimates that 73,000 cases of E. coli O157:H7 occur

annually in the U.S., and that 61 fatal cases occur annually. The

illness is often misdiagnosed; therefore, expensive and invasive

diagnostic procedures may be performed. Patients who develop

severe disease may require prolonged hospitalization, dialysis, and

long-term follow-up (CDC, 2001b).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-28, for

more information.) 

Indicator Infectious disease prevalence – E. coli O157:H7 – Category 2

Indicator Infectious disease prevalence – Hepatitis A – Category 2

Hepatitis A virus (HAV) is one of five viruses in the hepatitis

group of viruses (A to E) that cause liver disease. Symptoms

include jaundice, fatigue, abdominal pain, loss of appetite, nausea,

diarrhea, and fever. Adults tend to be more symptomatic than 

children. HAV is found in the feces of infected people and is 

usually spread through contaminated food, water, or intimate 

contact (CDC, 2002d).

What the Data Show

The annual number of reported cases for HAV in the U.S. 

exceeds 10,000. The estimated number of new infections

approaches 100,000 per year. It continues to occur in epidemics

both nationwide and in communities. The number of cases is 

now reaching historic lows and continues to slowly decline, though

about one-third of Americans show evidence of past infection

(CDC, 2002e).

Data Source

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-28, 

for more information.) 
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Salmonellosis is a disease caused by one of the more than 2,000

strains of the bacterial genus Salmonella. Most persons infected

with Salmonella develop diarrhea, fever, and abdominal cramps 12

to 72 hours after infection. The illness usually lasts 4 to 7 days,

and most persons recover without treatment, though antibiotics

can be used. In some persons, however, the diarrhea may be so

severe that the patient needs to be hospitalized. In these patients,

the Salmonella infection may spread from the intestines to the

bloodstream and then to other body sites. It can cause death

unless the person is treated promptly with antibiotics. The elderly,

infants, and those with impaired immune systems are more likely

to become severely ill from salmonellosis (CDC, 2001f).

What the Data Show

Every year, approximately 40,000 cases of salmonellosis are

reported in the U.S. Because many milder cases are not diagnosed

or reported, CDC estimates the actual number of infections to be

1.4 million. Salmonellosis is more common in the summer than

winter. It is estimated that somewhat more than 500 persons die

each year with acute salmonellosis (CDC, 2001f).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-29, for

more information.) 

Indicator Infectious disease prevalence – Salmonellosis – Category 2

Indicator Infectious disease prevalence – Shigellosis – Category 2 

4-30 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Shigellosis is a bacterial disease affecting the intestinal tract.

Anyone can get shigellosis, though it is most common in children

between the ages of 1 and 14. Most who are infected with Shigella

develop diarrhea, fever, and stomach cramps starting a day or two

after they are exposed to the bacterium. The diarrhea is often

bloody. Shigellosis usually resolves in 5 to 7 days. In some persons, especially young children and the elderly, the diarrhea can

be so severe that hospitalization is necessary. Some persons who

are infected may have no symptoms at all, but may pass the

Shigella bacteria to others (CDC, 2001g).

What the Data Show

Every year, about 14,000 cases of shigellosis are reported in the

U.S. Because many milder cases are not diagnosed or reported,

the CDC estimates the actual number of infections to be

448,000. Shigellosis is particularly common and causes recurrent

problems in settings where hygiene is poor (CDC, 2001g).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-29, 

for more information.) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-31

Typhoid fever is a life-threatening illness caused by the bacterium

Salmonella typhi. Typhoid fever is characterized by fever, headache,

nausea, and loss of appetite. Salmonella typhi lives only in humans.

Persons with typhoid fever carry the bacteria in their bloodstream

and intestinal tract. In addition, a small number of persons (2 to 5

percent), called carriers, recover from typhoid fever but continue

to carry and shed the bacteria. Both ill persons and carriers shed

S. typhi in their feces and urine (WHO, 1997).

What the Data Show

In the U.S., about 400 S. typhi cases occur each year, many of

which are acquired while traveling internationally. Typhoid fever is

transmitted by eating food or drinking beverages that have been

handled by a person who is shedding S. typhi, or by consuming

water contaminated with S. typhi bacteria (CDC, 2001h).

Data Source 

National Notifiable Diseases Surveillance System, Centers for

Disease Control and Prevention. (See Appendix B, page B-30, 

for more information.) 

Indicator Infectious disease prevalence – Typhoid fever – Category 2

4.3.4 What are the trends for

children’s environmental health

issues?

Special consideration must be given to children’s health issues

because children may be more susceptible to disease and generally

may be more vulnerable to their surroundings for many physiological

reasons. This section discusses five indicators for children’s

environmental health issues: infant mortality, low birthweight,

childhood cancer, childhood asthma, and birth defects.
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Infant mortality in the U.S. is defined as the death of a child

before age 1.

What the Data Show

In 1999, a total of 27,937 deaths occurred in infants under 1 year

of age (Hoyert, et al., 2001). The infant mortality rate was 7.1 per

1,000 live births, the lowest ever recorded in the U.S. The infant

mortality rate for African American infants was 14.6 per 1,000

live births, more than twice the rate for White infants (5.8 per

1,000 live births). The infant mortality rate for Hispanic infants

was 5.8 per 1,000 live births. The 10 leading causes of infant

deaths account for 67.6 percent of all infant deaths in the U.S.

(Exhibit 4-23). Delaware, Maine, Massachusetts, and Utah have

the lowest infant mortality rates. Mississippi, Alabama, and

Louisiana have the highest (Hoyert, et al., 2001).

Data Source 

National Vital Statistics System, Centers for Disease Control and

Prevention. (See Appendix B, page B-30, for more information.) 

Indicator Infant mortality – Category 1 

4-32 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Exhibit 4-23: Number of infant deaths, percent of total deaths, and infant 

mortality rates for the 10 leading causes of infant death, United States, 1999

All causes

Congenital malformations, deformations, and 

chromosomal abnormalities

Disorders related to short gestation and low 

birthweight

Sudden Infant Death Syndrome

Newborn affected by maternal complications of 

pregnancy

Respiratory distress of newborn

Newborn affected by complications of placenta, cord, 

and membranes

Accidents

Bacterial sepsis of newborn

Diseases of the circulatory system

Atelectasis

All other causes

27,937

5,437

4,392

2,648

1,399

1,110

1,025

845

691

667

647

9,040

1

2

3

4

5

6

7

8

9

10

705.6

138.2

110.9

66.9

35.3

28.0

25.9

21.3

17.5

16.8

16.3

228.3

100.0

19.6

15.7

9.5

5.0

4.0

3.7

3.0

2.5

2.4

2.3

32.4

Rank Cause of Death Deaths Rate

Percent of 

Total Deaths

Rate is per 100,000 live births in 1999.

Source: Hoyert, D.L., et al. Deaths: Final Data for 1999. 2001. 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-33

An infant with low birthweight is defined as a full-term infant, born

between week 37 and 44 of pregnancy, and weighing 2,500

grams or less at birth. Weight is a critical health measure because

low birthweight children are more prone to death and disability

than their counterparts.

What the Data Show

The percentage of infants who were born with a low birthweight

(weighing less than 2,500 grams) was 7.6 percent in 2000

(Martin, et al., 2002). In 2000, the low birthweight rate for nonHispanic African Americans (13.1 percent) was twice the rate of

that for non-Hispanic Whites (6.6 percent), a relationship that

existed for at least the 9 prior years as well (Exhibit 4-24). In

2000, the low birthweight rate for Hispanics was similar to that of

non-Hispanic Whites (6.4 and 6.6, respectively). Also shown in

Exhibit 4-24 is that non-Hispanic African Americans had the

highest proportion of very low birthweight infants (weighing 

less than 1,500 grams) in 2000, compared with Hispanic and

non-Hispanic White populations in the U.S.

Data Source 

National Vital Statistics System, Centers for Disease Control and

Prevention. (See Appendix B, page B-30, for more information.) 

Indicator Low birthweight – Category 1

Exhibit 4-24: Percent of live births of very low birthweight and low birthweight, 

by race and Hispanic origin of mother, United States, 1991-2000

White

Non-Hispanic

Black

Non-Hispanic Hispanic

Very Low Birthweight Low Birthweight

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1Less than 1,500 grams (3 lb. 4 oz.)

2Less than 2,500 grams (5 lb. 8 oz.)

3Includes all persons of Hispanic origin of any race.

Source: Martin, J.A., et al. Births: Final Data for 2000. 2002.

1.14

1.15

1.15

1.12

1.08

1.04

1.01

1.00

0.94

0.94

3.10

3.18

3.11

3.05

3.02

2.98

2.99

2.99

2.97

2.97

1.14

1.14

1.15

1.13

1.12

1.11

1.08

1.06

1.04

1.02

White

Non-Hispanic

Black

Non-Hispanic Hispanic

6.6

6.6

6.6

6.5

6.4

6.2

6.1

5.9

5.7

5.7

13.1

13.2

13.2

13.1

13.1

13.2

13.3

13.4

13.4

13.6

6.4

6.4

6.4

6.4

6.3

6.3

6.2

6.2

6.1

6.1

1 2

3 3
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Cancer is a disease characterized by uncontrolled growth of cells.

A cancerous cell loses its ability to regulate its own growth, control cell division, and communicate with other cells. These cellular

changes are complex and occur over a period of time. They may

be accelerated in children. Cancer cells can invade nearby tissues

and can spread through the bloodstream and lymphatic system to

other parts of the body (NCI, 2003). The classification of cancers

in children differs from the classification used for adult cancers. 

What the Data Show

In 1999, there were nearly 2,200 deaths due to cancer in children

and adolescents under 20 years of age (Anderson, 2001). The

age-adjusted cancer mortality rates by race and age group are

presented in Exhibit 4-25. In 1999, cancer was the third leading

cause of death in children 1 to 4 years of age, accounting for 8

percent of the total deaths in this age group (Anderson, 2001).

The death rate for cancer in this age group was 2.8 per 100,000

population. For children 5 to 9 years of age, cancer was the second leading cause of death accounting for 14.7 percent of total

deaths. The death rate was 2.6 per 100,000 for children 5 to 9

years of age. In older children (15 to 19 years of age), 5.4 

percent of total deaths in this age group were due to cancer.

Cancer ranked fourth among leading causes of death, with a 

mortality rate of 3.8 per 100,000 population.

Exhibit 4-26 presents the age-adjusted incidence rates for cancers

in children of all races between the ages of 0 and 19 years, 1975

to 1998. There has been an increase in the incidence for all types

of childhood cancer since 1975. There also has been a substantial

decline in the cancer death rate for children, largely due to

improved treatment (EPA, December 2000).

Data Sources 

Mortality: National Vital Statistics System, National Center 

for Health Statistics. (See Appendix B, page B-31, for

more information.)

Incidence: Surveillance, Epidemiology, and End Results Program,

National Cancer Institute. (See Appendix B, page B-31, 

for more information.) 

Indicators Childhood cancer mortality – Category 1

Childhood cancer incidence – Category 2

4-34 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Exhibit 4-25: Age-adjusted Surveillance, Epidemiology and End Results (SEER) childhood cancer (all sites) incidence 

and United States mortality rates by race and age group, 1994-1998

Incidence Mortality Incidence Mortality

Ages 0-14 Ages 0-19

Race

All Races

White

Black

Rates are deaths per 100,000 per year and are age adjusted to the 1970 U.S. standard population.

Source: Ries L.A.G., et al. SEER Cancer Statistics Review, 1973-1988. 2001

Total

14.4

14.8

12.0

Male

15.4

15.6

13.0

Female

13.4

13.9

10.9

Total

2.7

2.7

2.8

Male

3.0

3.0

2.9

Female

2.4

2.4

2.6

Total

15.9

16.4

12.5

Male

16.7

17.2

13.3

Female

15.0

15.6

11.7

Total

3.0

3.0

3.1

Male

3.3

3.4

3.2

Female

2.6

2.6

2.9
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-35

Indicators Childhood cancer mortality – Category 1 (continued)

Childhood cancer incidence – Category 2 (continued)

Notes: Rates are cases per 1,000,000 per year and are age adjusted to the 1970 U.S. standard population.

Source: Ries, L.A.G., et al. SEER Cancer Statistics Review, 1973-1998. 2001.

1975-1980

140.0

33.2

24.1

23.4

7.7

2.6

6.0

1.2

7.8

10.4

8.6

13.9

All groups combined

 Leukemia

 Lymphomas and 

reticuloendothelial 

neoplasms

 Central nervous system

 Sympathetic nervous 

system tumors

 Retinoblastoma

 Renal tumors

 Hepatic tumors

 Malignant bone tumors

 Soft tissue sarcomas

 Germ cell, trophoblastic 

and other gonadal 

neoplasms

 Carcinomas and other 

malignant epithelial 

neoplasms

149.0

36.3

24.9

24.3

8.1

2.7

6.6

1.5

9.2

10.9

9.8

13.5

157.5

37.6

24.8

29.6

7.6

2.9

6.3

1.7

8.9

11.2

11.3

14.6

159.1

37.4

23.9

27.8

8.5

3.1

7.1

1.8

9.4

11.4

11.7

15.0

1981-1986 1987-1992 1993-1998

Exhibit 4-26: Age-adjusted Surveillance, Epidemiology and End Results (SEER) cancer incidence rates by 

international classification of childhood cancer (ICCC) selected group and subgroup and year of diagnosis, 

children 0 to 19 years, 1975-98
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Asthma is a chronic respiratory disease characterized by inflammation of the airways and lungs. During an asthma attack, the

airways that carry air to the lungs are constricted. As a result,

less air is able to flow in and out of the lungs (NCHS, 2001).

Currently, there are no preventive measures or cure for asthma;

however, children and adolescents who have asthma can still lead

quality, productive lives if they control their asthma. Asthma can

be controlled by taking medication and by avoiding contact with

environmental “triggers” for asthma. Environmental triggers

include cockroaches, dust mites, furry pets, mold, tobacco smoke,

and certain chemicals (CDC, 2002g; CDC, 2003b).

What the Data Show

In 2001, approximately 6 million (9 percent) of U.S. children had

asthma, compared to approximately 3.6 percent of children in

1980 (EPA, 2003a).

In 1999, there were 32 deaths due to asthma for children

under 5 years of age and 144 deaths for children 5 to 14 years

of age (Mannino, et al., 2002). This number is slightly lower

than the 189 asthma deaths among children under 15 years 

of age in 1998.

Boys were more likely to have been diagnosed with asthma than

girls; the condition was diagnosed in 13 percent of boys

compared with 10 percent for girls. Of the 4 million children who

reported that they had an asthma attack in the last 12 months,

boys were most likely to have had an attack when they were 5 to

11 years of age. Girls were most likely to have had an attack in the

previous year at 12 to 17 years of age. Fourteen percent of nonHispanic African American children had been diagnosed with

asthma. The proportion of non-Hispanic White and Hispanic

children who had ever been diagnosed with asthma was nearly the

same, 11 percent and 10 percent, respectively. Asthma rates in

children have increased since 1980, especially for children age 4

and younger and for African-American children (Exhibit 4-27).

Data Sources 

Mortality: National Vital Statistics System, National Center 

for Health Statistics. (See Appendix B, page B-31, 

for more information.)

Prevalence: National Health Interview Survey, Centers for

Disease Control and Prevention (See Appendix B, page B-32,

for more information.)

Indicators Childhood asthma mortality - Category 1 

Childhood asthma prevalence – Category 1

4-36 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

Exhibit 4-27: Asthma prevalence, 1980-1996, asthma lifetime diagnosis, current asthma, and 

asthma attack prevalence, 1997-2001, in children

Number of children with asthma per 1000 children 17 years of age or younger

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1999 1997 2000 2001 1998

0

20

40

60

80

100

120

140

Note: The survey questions for asthma changed in 1997; data before 1997 cannot be directly compared to data in 1997 and later.

Source: Based on and updated from Akinbami, L.J. and K.C. Schoendorf. Trends in Childhood Asthma: Prevalence, Health Care Utilization and Mortality. 2002. Data from 

CDC, National Center for Health Statistics, National Health Interview Surveys, 1980-2001.

Asthma prevalence

Asthma lifetime diagnosis

Asthma attack prevalence

Current asthma prevalence
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-37

Congenital anomalies, or birth defects, are structural defects

that are present in the fetus at birth. Because the causes of

about 70 percent of all birth defects are unknown, the public

continues to be anxious about whether environmental pollutants cause birth defects, developmental disabilities, or other

adverse reproductive outcomes. The public also has many

questions about whether various occupational hazards, 

dietary factors, medications, and personal behaviors cause or

contribute to birth defects (CDC, 2002c).

What the Data Show

Birth defects (congenital anomalies) are a leading cause of

infant deaths, accounting for 5,473 (19.6 percent) of the

27,937 infant deaths in 1999 (Hoyert, et al., 2001). The most

frequently occurring types of birth defects were those affecting

the heart and the lungs. Because some birth defects are not

recognized immediately, they are underreported on the death

certificate, so the numbers underestimate the problem (Friis, et

al., 1999). Exhibit 4-28 presents the number and rate of live

births with congenital anomalies.

Data Source

National Vital Statistics System, 

National Center for Health Statistics.

(See Appendix B, page B-32, 

for more information.) 

Indicators Deaths due to birth defects – Category 1

Birth defect incidence – Category 1

Anencephalus

Spina bifida/Meningocele

Hydrocephalus

Microcephalus

Other central nervous system anomalies

Heart malformations

Other circulatory/respiratory anomalies

Rectal atresia/stenosis

Tracheo-esophageal fistula/Esophageal atresia

Omphalocele/Gastroschisis

Other gastrointestinal anomalies

Malformed genitalia

Renal agenesis

Other urogenital anomalies

Cleft lip/palate

Polydactyly/Syndactyly/Adactyly

Clubfoot

Diaphragmatic hernia

Other musculoskeletal/integumental anomalies

Down's syndrome

Other chromosomal anomalies

425

822

940

284

822

4,958

5,484

333

481

1,180

1,185

3,344

547

3,943

3,259

3,460

2,271

427

8,614

1,863

1,575

10.7

20.7

23.7

7.2

20.7

124.9

138.1

8.4

12.1

29.7

29.9

84.2

13.8

99.3

82.1

87.2

57.2

10.8

217.0

46.9

39.7

Congenital Anomaly

(All races)

Number of Congenital 

Anomalies Reported Rate

Rates are number of live births with specified congenital anomaly per 100,000 live births in 

specified group.

Note: Of the 4,031,591 live births, there was no response recorded for the congenital anomaly item 

for 61,744 births.

Source: Martin, J.A., et al. Births: Final Data for 2000. 2002. 

Exhibit 4-28: Number and rate of live births with selected congenital 

anomalies, United States, 2000
4-38 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

4.3.5 What are the trends for

emerging health effects?

In addition to the diseases reported in the preceding pages, several

other diseases are the cause of emerging concern because of their

potential impacts on the health of the U.S. population. Information

for eight such diseases—diabetes, Alzheimer’s disease, Parkinson’s

disease, renal disease, autism, and three arthropod-borne diseases

(Lyme disease, Rocky Mountain spotted fever, and West Nile

virus)— is presented in this section. The increasing prevalence of

these “emerging” illnesses positions them as potential future candidates for consideration as EPHIs. This will be dependent on their

increasing prevalence in the population or a better determination 

of the role of exposure to environmental pollutants in the onset or

exacerbation of these diseases. No specific indicators have been

presented for these diseases at this time, but data collected by the

CDC, individual states, and other sources illustrate the recent

trends in these diseases.

Diabetes

Diabetes is a set of metabolic disorders. Diabetes mellitus (type 2) is

the most common form of diabetes and is a disease whereby the

body’s insulin activity is altered. Insulin is a hormone that signals

many biological processes such as the conversion of glucose to

glycogen. Glycogen is the form in which food energy is stored in the

body. The general symptoms of diabetes are elevated blood glucose

levels, excessive thirst, frequent urination, and unexplained weight

loss. Heredity, obesity, and age are factors that also contribute to

diabetes. Estimates of the prevalence of diabetes vary widely.

However, CDC estimates that there are about 11.1 million diagnosed

cases of diabetes (CDC, 2002b). In addition to these cases, CDC

estimates that there may be about 5.9 million more cases that are

undiagnosed (CDC, 2002b). The total of 17 million diagnosed and

undiagnosed cases combined amounts to a prevalence of 6.2 

percent of the U.S. population. CDC estimates that 1 million new

cases of diabetes are diagnosed per year among people aged 

20 years and older (CDC, 2002b).

In 1999, diabetes ranked as the sixth leading cause of death in the

U.S. There were 68,399 deaths due to diabetes (Hoyert, et al.,

2001). The age-adjusted death rates for diabetes increased between

1980 and 1996 from 15.3 to 20.6 per 100,000 people. By 1999,

the rate had risen to 25.2 per 100,000 people. 

On average, Hispanic Americans are 1.9 times more likely to have

diabetes than non-Hispanic Whites of similar age. The risk of 

diabetes for Mexican Americans and non-Hispanic Blacks is almost

twice that for non-Hispanic Whites. Similarly, residents of Puerto

Rico are 2.0 times more likely to have diagnosed diabetes than U.S.

non-Hispanic Whites. On average, American Indians and Alaska

Natives are 2.6 times more likely to have diabetes than non-Hispanic

Whites of similar age. Approximately 15 percent of American Indians

and Alaska Natives receiving care from the Indian Health Service have

diabetes. At the regional level, diabetes is least common among

Alaska Natives (5.3 percent) and most common among American

Indians in the southeastern U.S. (25.7 percent) and in certain tribes

from the Southwest (CDC, 2002b). Exhibit 4-29 shows age-adjusted prevalence data for diabetes in the U.S. by race/ethnicity.

Alzheimer’s Disease

Alzheimer’s disease is a neurodegenerative disorder. The symptoms

of Alzheimer’s disease may include dementia, loss of memory, and

decreasing physical abilities such as dressing or eating. In the U.S.,

an estimated 4 million people, mostly elderly, have Alzheimer’s disease (Hoyert and Rosenberg, 1999). In 1999, an estimated

354,000 non-institutionalized adults 18 to 64 years of age reported

Alzheimer’s disease as their main disability (CDC, 2001e). 

The death rate due to Alzheimer’s disease rose steadily from 1979 to

1996. In 1999, Alzheimer’s disease was the eighth leading cause of

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Exhibit 4-29: Age-adjusted prevalence of 

physician-diagnosed diabetes in persons 20 years of 

age and older, by race/ethnicity, United States, 2000

Percentage of population

16

14

12

20

18

10

8

6

4

2

0

Source: CDC. National Diabetes Fact Sheet. 2002. Data from CDC, National Center 

of Health Statistics, National Health Interview Survey, 1997-1999 and National 

Health and Nutrition Examination Survey, 1988-1994.

White, non-Hispanic

American Indians/ 

Alaska Natives

Black, non-Hispanic

Hispanic

Race/ethnicity category
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-39

death in the U.S. (Hoyert, et al., 2001). There were 44,536 deaths

attributed to Alzheimer’s disease (16.3 deaths per 100,000

population). The death rate for Alzheimer’s disease rises sharply with

age. In 1999, among people 75 to 84 years of age, there were

15,836 deaths and in this age group Alzheimer’s disease ranked as

the seventh leading cause of death (Anderson, 2001). The death

rate for Alzheimer’s disease for this age group was 130.4 per

100,000 population. Among persons 85 years of age and older,

there were 24,980 deaths due to Alzheimer’s disease for a death

rate of 598.3 per 100,000 population. 

Death rates for Alzheimer’s disease are higher for women than for

men and higher for Whites than African Americans (Hoyert, et al.,

2001). The 1999 death rates for Alzheimer’s disease are highest for

White females (25.6 per 100,000), followed by White males (11.4),

African American females (9.0), and African American males (4.2).

The Alzheimer’s disease death rate for Hispanics is 3.1 per 100,000.

Hispanic females have a higher death rate (4.3 per 100,000 population) than Hispanic males (2.0 per 100,000). The death rates from

Alzheimer’s disease are higher in the Northeast and in the Northwest

regions of the U.S. (Hoyert and Rosenberg, 1999). 

Parkinson’s Disease

Parkinson’s disease is a neurodegenerative disorder characterized by

symptoms such as tremors, muscle rigidity, and changes in walking

patterns. The National Institute of Neurological Diseases and Stroke

(NINDS) estimates that there are about 500,000 people in the U.S.

with Parkinson’s disease (NINDS, 2002). The disease mostly affects

elderly people and is second only to Alzheimer’s disease in the number of older people that are affected (Checkoway and Nelson,

1999). It affects about 0.4 percent of those 40 years of age and

older, 1 percent of those older than 65 years, and about 3 percent

of those 80 years of age and older. Males are 1.3 times more likely

than females to have Parkinson’s disease.

A steady increase in the death rate due to Parkinson’s disease among

people 75 years of age and older has been observed in the U.S. In

1999, there were 14,593 deaths due to Parkinson’s disease (Hoyert,

et al., 2001). Virtually all of the deaths (14,298) occurred in people

65 years of age and older. The death rate was 5.4 per 100,000

population, with males having a higher death rate than females (6.2

versus 4.5 per 100,000). 

The 1999 death rate due to Parkinson’s disease was higher for

Whites (6.2 per 100,000 people ) than for African Americans

(1.5 per 100,000) (Hoyert, et al., 2001). The death rate for

White males was 7.1 per 100,000 and for White females 5.3 per

100,000. The death rate for African American males was 1.6 and

for African American females 1.3 per 100,000. The death rate for

Hispanics was 1.2 per 100,000, with Hispanic males having a

slightly higher death rate (1.4 per 100,000) than Hispanic

females (1.1 per 100,000).

Renal Disease

The kidneys are vital organs and can be seriously affected by a

number of primary diseases such as diabetes or hypertension. As

these diseases progress, the kidneys may fail to function. Total and

permanent kidney failure is called end stage renal (kidney) disease

(ESRD). It is estimated that about 424,179 people in the U.S. have

ESRD (NIDDK, 2001). Most ESRD occurred in people who have

diabetes (150,404 people), hypertension (100,169 people), or

glomerulonephritis, a kidney disease (62,119 people). 

The U.S. government maintains the U.S. Renal Data System, which

provides information on the incidence, prevalence, and mortality for

ESRD (CDC, 2000a). Data from this system indicate that there were

89,252 people with ESRD who began treatment in 1999. These

cases of ESRD resulted from diabetes for 38,160 people and from

hypertension for 23,133 people. Kidney diseases and other primary

diseases were responsible for the remainder. 

Between 1979 and 1998, the age-adjusted death rates for all types

of kidney disease increased, peaking between 1984 and 1988. The

age-adjusted death rates for all types of kidney disease are higher

among African Americans than among Whites, with African American

males having the highest rates during the 1979 to 1998 period. 

In 1979, the death rate for total kidney disease was 8.6 per

100,000 people. By 1999, kidney disease had risen to rank as the

ninth leading cause of death in the U.S. (Hoyert, et al., 2001). That

year there were 35,525 deaths due to all types of kidney disease;

34,719 of them were due to kidney failure. The death rate for kidney

disease was 13.0 per 100,000 people; the death rate for kidney 

failure was 12.7 per 100,000 people (Exhibit 4-30). Death rates for

kidney failure were highest for African American females at 19.0 per

100,000, followed by African American males at 17.8 per 100,000.

African Americans and American Indians have higher rates of ESRD

than Whites or Asians (AHA, 2001). African Americans represent 32

percent of the patients receiving treatment for ESRD. Recently there

has been an increase in ESRD due to diabetes among American

Indians and Alaskan Natives (CDC, 2000c). Between 1990 and

1996, the age-adjusted rate of new ESRD treatment among

American Indians with diabetes increased 24 percent, from 472 to

584 per 100,000 persons with diabetes.

Autism

Autism is one of several related severe cognitive and neurobehavioral

disorders that are classified under the term autistic spectrum

disorders. Information about the prevalence of autism in the U.S. is

limited, reflecting the use of different diagnostic criteria and a lack of

research. First described in the 1940s, autism was thought to affect

2 to 4 children per 10,000 population. Today the prevalence is

currently believed to be as high as 1 in 500 children` for all autistic
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4-40 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease Chapter 4 - Human Health

spectrum disorders (Iversen, 2000). Currently, autism affects about

400,000 people in the U.S., and occurs about four times more often

in boys than in girls.

Researchers have reported that the number of persons with autism is

increasing. For example, a recent California Department of

Developmental Services (CDDS) report showed an over 200 percent

increase in the number of persons entering the regional center 

service system with autism between 1987 and 1998 (CDDS, 1999).

Other states have reported increasing numbers as well (Yazbak,

1999). However, these reports do not necessarily reflect a change in

the rate of autism because they do not consider the increase in the

total population (Fombonne, 2001).

The number of cases of autism in children in the U.S. has increased

over time. The number of children 0 to 21 years old with autism who

are also enrolled in federally supported programs for the disabled

has grown from 5,000 in 1991 to 79,000 in 2000 (NCES, 2001).

This represents an increase from 0.1 to 1.1 percent of all children

with disabilities served, or an increase from 0.01 to 0.14 percent of

all children in public schools.

Arthropod-Borne Diseases

Certain ticks and mosquitoes (arthropods) can carry bacteria and

viruses that cause disease in humans. They acquire the bacteria and

viruses when they bite an infected mammal or bird. Arthropod-borne

diseases include Lyme disease, Rocky Mountain spotted fever

(RMSF), and West Nile virus (WNV).

Lyme Disease

Lyme disease is the most commonly reported arthropod-borne 

disease in the U.S. (Orloski, et al., 2002). The illness was first

described in Europe during the 1800s; however, it was not identified

in the U.S. until the early 1970s when a cluster of children with

“juvenile rheumatoid arthritis” in Lyme, Connecticut, was reported 

by their parents (Shapiro and Gerber, 2000). Investigation of the

cluster led to the description of Lyme arthritis in 1976 and then to

the identification of the causal pathogen. Between 1992 and 1998,

there were 88,967 cases of Lyme disease reported to the CDC. 

The number of cases increased from 9,896 in 1992 to 16,802 in

1998 (Exhibit 4-31).

The incidence of Lyme disease was highest in eight northeastern and

mid-Atlantic states and two north central states. These states

accounted for 92 percent of the total cases.

Rocky Mountain Spotted Fever

Although Lyme disease is the most commonly reported tick-borne

disease in the U.S., RMSF is the most commonly fatal tick-borne 

disease in the U.S. (Holman, et al., 2001). Physicians first recognized

RMSF in the northwestern U.S. during the late 1800s; Howard

Ricketts identified the causal pathogen in the early 1900s (Gayle

and Ringdahl, 2001; Paddock, et al., 1999). RMSF was the first 

disease in the U.S. shown to be transmitted by tick bite (Walker,

1998). Although RMSF was first identified in the Rocky Mountain

states, fewer than 3 percent of cases were reported from that area

between 1993 and 1996. The highest incidence of cases in that time

period was found in North Carolina and Oklahoma. These two states

accounted for 35 percent of the total cases from 1993 to 1996

(CDC, 2002c). RMSF has been reported throughout the continental

U.S. (except in Maine, New Hampshire, and Vermont).

Between 1990 and 1998, there were approximately 4,800 cases of

RMSF reported to the CDC (CDC, 2000b). The annual number of

cases has varied between 250 and 1,200 cases since 1942, with a

peak between 1975 and 1981.

The ratio of the number of deaths due to RMSF compared to the

number of cases of the disease is the highest in children under 10

Exhibit 4-30: Death rates for kidney disease, United States, 1999

Cause 

of Death

Nephritis, nephrotic 

syndrome, nephrosis

Kidney failure

Other

13.0 12.8 13.3

12.7 12.5 13.0

 0.3 10.3 0.3

12.5 12.4 12.6

12.2 12.1 12.3

 0.3 0.3 0.3

15.6 14.8 16.3

15.2 14.4 16.0

 0.4 0.4 0.3*

19.3 18.2 20.2

18.9 17.8 19.0

 0.4 0.4* 0.4*

Both Male Female

Sexes 

Both Male Female

Sexes 

Both Male Female

Sexes 

Both Male Female

Sexes 

All Races White All Other Black

Rates are per 100,000 population.

*Figure does not meet the standards of reliability or precision.

Source: Hoyert, et al. Deaths: Final Data for 1999. 2001.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.3 Health Status of the U.S.: Indicators and Trends of Health and Disease 4-41

years of age (2 to 3 percent) and those over 70 years of age (9

percent) (CDC, 2000b).

West Nile Virus

In 1937, WNV, a strain of encephalitis, was first identified as a human

pathogen in the West Nile region of Uganda. The pathogen was

found in blood taken from a woman during a yellow fever

investigation (Rappole, et al., 2000). Since 1937, WNV has been

determined to be widespread in many areas of the world, particularly

Africa, the Middle East, Europe, Russia, India, and Indonesia 

(Horga and Fine, 2001).

Cases of WNV were first documented in the U.S. in 1999 (CDC,

2000d). A total of 80 cases in humans were reported in 1999 

(62 cases) and 2000 (18 cases). Because severe neurological illness

(encephalitis meningitis) occurs in fewer than 1 percent of persons

infected, it is thought that a greater number of cases with less 

severe symptoms may go unreported. Based on this assumption, 

it is estimated that approximately 2,000 persons may have been

infected with WNV during 2000 (CDC, 2000d). The prevalence of

the disease in humans is increasing. During 2002 there were 3,989

diagnosed cases in humans (CDC, 2002f). The number of deaths

caused by West Nile encephalitis has increased from 7 in 1999 to

259 in 2002 (CDC, 2002f). 

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Exhibit 4-31: Number of reported cases of Lyme disease, United States, 1982-1998

Number of reported cases

20,000

15,000

10,000

5,000

0

Source: Orloski K.A., et al. Surveillance for Lyme Disease. 2002.

Year
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4-42 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

4.4 Measuring Exposure

to Environmental Pollution:

Indicators and Trends 

Historically, human exposure to pollutants has been estimated

based on:

■ Measurements of ambient pollutant concentrations in air, water,

or land, combined with:

■ Estimates or measurements (through personal monitoring) of

the frequency and duration of human contact with the 

contaminated media. 

This approach has provided a valuable foundation for many of the

regulatory and non-regulatory actions that have been taken to limit

exposure to ambient pollutants. However, ambient measurements do

not provide information on the degree to which ambient pollutants

actually enter into the body. Another type of indicator—biomonitoring data—can help provide this information. Biomonitoring measures

the amount of a pollutant in human tissue or fluids. It provides an

important complement to more traditional exposure assessment 

indicators. National-scale biomonitoring data can be used to:

■ Measure and track average body burden resulting from exposure

across the entire population to a variety of pollutants. 

■ Enhance environmental disease prevention efforts by providing an

important bridge to understanding the relationships between

ambient pollutant concentrations, exposures to these pollutants,

and health problems. (The lead case study, discussed earlier in

Section 4.1, provides an excellent example of this application.)

■ Establish reference ranges to identify people with unusually high

exposures or the percentage of the population with pollutant

exposures above established levels of concern (CDC, 2003a).

This section focuses primarily on biomonitoring indicators and is

divided into ten parts:

■ Section 4.4.1 provides background information on biomonitoring

indicators—what they are and their limitations.

■ Section 4.4.2 describes the major data sources for these 

indicators. 

■ Sections 4.4.3 to 4.4.8 describe specific pollutants and the data

available to monitor these pollutants, including heavy metals

(Section 4.4.3), cotinine (Section 4.4.4), volatile organic compounds (Section 4.4.5), pesticides (Section 4.4.6), and persistent organic pollutants (Section 4.4.7). Section 4.4.8 presents

indicators that are available to specifically monitor children’s exposure to some of these pollutants. In all, 10 biomonitoring indicators are currently available for tracking trends in human exposure

to specific environmental pollutants. Summaries of the data linking

exposure to human health effects can be found in ATSDR’s toxicological profiles and EPA’s criteria documents for these chemicals.

■ Section 4.4.9 briefly discusses a number of pollutants—radiation,

air pollutants (except for lead), biological pollutants, and

disinfection by-products —for which no biomonitoring indicators

currently are available or feasible. For these pollutants, traditional

exposure assessment will continue to serve as the method for

estimating human exposure until biomonitoring indicators become

available or feasible.

■ Finally, Section 4.4.10 touches on endocrine disruptors—

considered an emerging issue.

4.4.1 Biomonitoring Indicators

“Dose” (the amount of a pollutant that enters the body) is often

expressed as average daily dose or total potential dose. Once a

pollutant crosses the boundary into the body, biological processes

act on that contaminant to utilize, remove, or store the contaminant

and/or its metabolites. Body burden is the concentration of a

contaminant dose that is retained in the human body. Body burden

can be estimated from measurements of the contaminant in the

blood, urine, or adipose tissue. These measurements provide the

basis for biomonitoring indicators. 

The buildup of a contaminant in the body (i.e., the level of body

burden) depends on a variety of factors, including the nature of the

contaminant; the efficacy of the biological removal processes; and

the magnitude, timing, frequency, and duration of exposure. Some

contaminants, such as lead, are not easily removed and are retained

in the body for long periods of time. Other contaminants, such as

many volatile organic compounds (VOCs), are rapidly eliminated in

exhaled breath or other removal processes. 

The level of body burden is usually estimated from the concentration

of a contaminant (or its metabolite) measured in the blood, urine,

hair, or adipose tissue, and can be used to infer that an exposure

occurred. In some cases, the level of body burden associated with a

particular contaminant may prove to be an indicator of the person’s

extent of exposure to that pollutant. 

There are a number of potential problems, however, with using body

burden as an indicator of exposure. In some cases, several different

pollutants may give rise to the same biomarker. Further, most

measures of body burden reflect only a “snapshot” in time and many

different exposure scenarios can lead to the same concentration

measurement. Lastly, the measure gives no information about how

the person was exposed. 
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-43

Nonetheless, national scale measures of body burden are useful 

indicators of exposure in the population. While such measures do

not necessarily provide information about the nature of the exposures, they do represent the average levels of exposure in the population as a whole. Such national scale measures of body burden are

often more convenient to obtain than to estimate the exposures by

accounting for all of the exposure concentrations and durations for

the whole population. As mentioned earlier, body burden (biomonitoring) data are not available for all pollutants of interest to EPA. In

such cases, ambient data or exposure measurements and models are

used to assess human exposure.

4.4.2 Data Sources for Biomonitoring Indicators

Two primary sources provided data for the biomonitoring indicators

presented in this section:

■ The National Health and Nutrition Examination Survey

(NHANES), conducted by the National Center for Health

Statistics (NCHS). Specifically, data were used from the second,

third, and fourth surveys (NHANES II; NHANES III; and NHANES

IV [1999-2000]).

■ EPA’s National Human Exposure Assessment Survey

(NHEXAS). Specifically, data were used from surveys of three

regions: Maryland, EPA Region 5, and Arizona (NHEXAS–MD;

NHEXAS–Region 5; and NHEXAS–AZ).

Two others sources of biomonitoring data—autopsy data and tissue

registry data—were considered but not used for these indicators. As

described below, neither of these sources contains rich biomonitoring data, which significantly limits their usefulness as data sources for

human contaminant levels. 

National Center for Health Statistics, National Health and

Nutrition Examination Survey (NHANES) 

NHANES consists of a series of surveys conducted by CDC’s

NCHS. The survey is designed to collect data on the health of the

U.S. population, including information on topics such as nutrition,

cardiovascular disease, and exposure to chemicals (CDC, 2001c).

The NHANES surveys have been performed over a number of

years. The first survey, NHANES I, took place from 1971 through

1975; NHANES II occurred from 1976 through 1980; NHANES III

was performed from 1988 through 1994; and the most recent

NHANES for which data are available took place in 1999-2000. In

this section, the year(s) in which the data were collected are 

identified in each citation of NHANES.

As part of the survey, blood and urine samples were collected to

measure the amounts of certain chemicals thought to be potentially

harmful to people. Because of the extensive work involved with 

laboratory analysis, some chemicals were measured for all people in

the survey, while other chemicals were only measured in representative subsamples of people in an age group.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) (CDC,

2001c) summarizes chemical exposure data from NHANES.

Information from the CDC report is presented hereafter under the

heading “NHANES 1999-2000.” To date, this report has been

released twice. Data from the first report are updated in the larger,

second report. The second report represents the U.S. population

over a 2-year period, 1999-2000. Two years of data provide more

stable estimates for the total population and are necessary for

adequate sample sizes for some subgroup analysis. Future reports

will be released every 2 years and will cover data for a 2-year 

period (e.g., 2001-2002, 2003-2004, 2005-2006).

National Human Exposure Assessment Survey

(NHEXAS)

The goal of NHEXAS was to better understand the complete picture

of human exposure to toxic chemicals by looking at humans’ many

exposures to all types of toxic chemicals. NHEXAS was a multiday,

multimedia study that examined chemical concentrations in indoor

air, outdoor air, dust, soil, food, beverages, drinking water, and tap

water. For some contaminants, body burden measurements were

obtained from samples of blood, hair, or urine. 

Phase 1 of NHEXAS consisted of demonstration and scoping studies

in Maryland; Phoenix, Arizona; and EPA Region 5 using probabilitybased sampling designs. Although the study was conducted in three

different regions of the U.S., it was not designed to be nationally

representative. The Region 5 study was conducted in Ohio,

Michigan, Illinois, Indiana, Wisconsin, and Minnesota and measured

metals and VOCs. The Arizona study measured metals, pesticides,

and VOCs. The target population for the NHEXAS-MD study 

consisted of the non-institutionalized permanent residents of households in the city of Baltimore or four counties in Maryland. Samples

from select environmental and biological media, as well as questionnaire data, were collected in NHEXAS-MD. The three NHEXAS 

studies are identified in this section as NHEXAS-AZ, NHEXASRegion 5, or NHEXAS-MD, to indicate where they were performed.

Autopsy Data

Autopsies can provide important information about deaths resulting

from known or suspected environmental or occupational hazards. For

example, one of the earliest indications of the rise in lung cancer

deaths came from reports that lung cancers were being identified

with increasing frequency in autopsies (Hanzlick, 1998).

The value of an autopsy database for body burden and

epidemiologic studies has been recognized; however, few such

studies have been conducted. This is partly because autopsies are
4-44 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health 

performed on a non-random sample of deaths and because

environmental contaminant levels are typically not measured during

an autopsy (Moore, et al., 1996). Also, autopsies are performed on

only a small percentage of the U.S. population. In 1980, autopsies

were performed in approximately 17 percent of deaths in the U.S. By

1985, the percentage had declined to 14 percent. While nearly all

deaths due to homicide and other medico-legal causes were

autopsied, autopsies were performed in only 12 percent of all deaths

due to natural causes (CDC, 1998a).

Difficulties in accessing autopsy data can limit their usefulness as

well. Prior to 1995, the National Center for Health Statistics (NCHS)

collected data from death certificates indicating whether an autopsy

was performed. Since that time, however, such information is no

longer available from the NCHS national mortality statistics 

databases (Hanzlick, 1998).

Tissue Registry Data

Human tissues are stored for study in many forms including solid

organs, organ sections, histology slides, cells, and DNA. Tissue

registries are maintained for medical education and biological

research, but few studies have been conducted to identify trends in

environmental contaminants in tissues using tissue registries. Tissue

registry samples and information are not population-based, and at

present there is no central database containing information about

tissue samples (Eiseman and Haga, 1999).

EPA has conducted one of the most extensive tissue studies. From

1976 to 1987, the EPA conducted the National Human Adipose

Tissue Survey (NHATS). NHATS was a national survey that

collected adipose tissue samples to monitor exposure to toxic

compounds among the general population. Pathologists and

medical examiners from 47 metropolitan areas collected samples

from autopsies and elected surgeries (Crinnion, 2000; Orban, et

al., 1994). Even though the study was a significant biomonitoring

effort, data from NHATS are not presented in this report because

newer data sources are available.

4.4.3 What is the level of exposure

to heavy metals?

Heavy metals are important environmental pollutants because they

are related to several adverse health effects when ingested or

inhaled. Five metals have been selected for in-depth presentation in

this section: chromium, lead, arsenic, mercury, and cadmium. These

metals are known to be related to severe adverse health effects and

are relatively common in household, work, and school environments.

Exhibit 4-32 presents EPA regulatory standards and guidelines for

these five metals. Indicators are available for lead, arsenic, mercury,

and cadmium and are discussed on the following pages. At present,

no indicator is available for chromium, but it is discussed below

because human health may be adversely affected by chromium in 

the environment. (For additional information on heavy metals in the

environment, see Chapter 1, Cleaner Air.)

Chromium

Chromium is a naturally occurring element found in rocks, animals,

plants, soil, and in volcanic dust and gases. Chromium is present in

the environment in several different forms, but primarily in two

valence states: trivalent chromium (III) and hexavalent chromium (VI).

Chromium (III) is an essential nutrient and is much less toxic than

chromium (VI), which is generally produced by industrial processes.

Chromium (III) and chromium (VI) are used for chrome plating, dyes

and pigments, leather tanning, and wood preserving (ATSDR, 2001). 

In air, chromium compounds are present mostly as fine dust particles

that eventually settle over land and water. Chromium can strongly

attach to soil and only a small amount can dissolve in water and

move deeper in the soil to underground water. Fish do not accumulate much chromium in their bodies from water (ATSDR, 2001). 

People can be exposed to chromium by eating food containing

chromium (III); breathing contaminated workplace air or experiencing

skin contact during use in the workplace; drinking contaminated well

water; or living near uncontrolled hazardous waste sites containing

chromium or near industries that use chromium (ATSDR, 2001).

Although studies have been conducted that measure the amount of

chromium in drinking water, ground water, soil, and air, there are no

studies that measure the body burden of chromium in human tissue.

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chromium III is an essential nutrient that helps the body use sugar,

protein, and fat. An intake of 50-200 μg of chromium (III) per day is

recommended for adults. On average, adults in the U.S. take in an

estimated 60-80 μg of chromium per day in food. Therefore, many

people’s diets may not provide enough chromium (III). Without

chromium III in the diet, the body loses its ability to use sugars,

proteins, and fat properly, which may result in weight loss or

decreased growth, improper function of the nervous system, and a

diabetic-like condition. Therefore, chromium (III) compounds have

been used as dietary supplements and are beneficial if taken in

recommended (but not excessive) dosages (ATSDR, 2000). Chronic

high exposures to chromium (III), however, may affect the skin, liver,

or kidneys (ACGIH, 1991; Rom, 1992).

In general, chromium (VI) is more toxic than chromium III. Breathing

in high levels (greater than 2 μg/m3) of chromium (VI), such as in a

compound known as chromic acid or chromium (VI) trioxide, can

irritate the nose, causing symptoms such as runny nose, sneezing,

itching, nosebleeds, ulcers, and holes in the nasal septum. These

effects have primarily occurred in factory workers who make or use

chromium (VI) for several months to many years. Long-term exposure

to chromium (VI) has been associated with lung cancer in workers

exposed to levels in air that were 100 to 1,000 times higher than

those found in the natural environment. Lung cancer may occur long

after exposure to chromium VI has ended (ATSDR, 2000).

No biomonitoring data are readily available for chromium. 

Interest is developing in examining chromium as an emerging

environmental pollutant. 

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-45

Exhibit 4-32: United States federal standards and criteria for five heavy metals

1. MCLs are regulatory standards developed pursuant to the Federal Safe Drinking 

Water Act (SDWA).

2. A groundwater cleanup level is most often the MCL (per the Comprehensive 

Environmental Response, Compensation, and Liability Act [CERCLA] [also known as 

Superfund] and Resource Conservation and Recovery Act [RCRA] guidance) for 

the particular contaminant. Groundwater cleanup levels are established by EPA and 

states on a case-by-case basis for Superfund site clean-ups and corrective actions 

at RCRA solid and hazardous waste management. 

3. This standard is a quarterly average. Lead is a criteria air pollutant (under the Clean 

Air Act) and therefore has a health-based standard.

4. This heavy metal is not a criteria air pollutant and thus there is not a health-based 

standard. Air pollution standards for this heavy metal are technology-based 

standards, not health-based standards. For example, the emission standard for 

arsenic is that which is achievable with the best available technology (BAT) for 

treating arsenic air emissions. In addition, the BAT for arsenic emissions varies 

across industry sectors and thus emission standards for arsenic also vary across 

industry sectors.

Source: EPA. Current Drinking Water Standards. 2002; EPA. EPA. Handbook of 

Groundwater Policies for RCRA Corrective Action. 2000; EPA. National Air Quality and 

Emissions Trends Report 1999. 2001.

Heavy

Metal

Drinking Water Maximum

Contaminant Level (MCL)1

Ground Water

Cleanup Level2

Air

Standards

Lead

Arsenic

Mercury

Chromium

Cadmium

0.015 mg/L

0.01 mg/L

0.002 mg/L

0.1 mg/L

0.005 mg/L

0.015 mg/L

0.01 mg/L

0.002 mg/L

0.1 mg/L

0.005 mg/L

1.5 μg/L3

Not Applicable4

Not Applicable5

Not Applicable4

Not Applicable4
Indicator

4-46 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health 

Blood lead level – Category 1 

Lead is a naturally occurring metal found in small amounts in rock

and soil. Lead has been used industrially in the production of

gasoline, ceramic products, paints, and solder. Lead-based paint

and lead-contaminated dust from paint are the primary sources of

lead exposure in the home. The body burden of lead can be 

measured as the amount of lead in blood or the amount of lead in

urine. The health effects of lead are discussed in Section 4.1 of

this chapter. 

What the Data Show

NHANES 1999-2000. The mean blood lead levels for adults are

illustrated in Exhibit 4-33. The mean blood lead level for all males

in the survey was 2.0 micrograms per deciliter (μg/dL) and 1.4

μg/dL for all females. The mean blood lead level for non-Hispanic

African Americans was 1.9 μg/dL. The mean blood lead level for

Mexican Americans was 1.8 μg/dL (CDC, 2001c).

NHANES III (1988-1994). Blood lead levels of people were 

surveyed in two separate phases of NHANES III. The data collected during Phase 2 (1991 through 1994) indicated that the U.S.

population’s exposure to lead was decreasing. 

NHEXAS-Region 5. Blood lead levels for 165 participants were

obtained during NHEXAS-Region 5. Lead levels in blood were

detectable for about 94 percent of the population; most of the

individuals had lead levels well below 10 μg/dL. The mean blood

lead level of the participants was 2.18 μg/dL (Clayton, et al.,

1999). 

Data Source 

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-33, for more information.) 

Exhibit 4-33: Geometric mean and selected percentiles of total blood lead concentrations (in μg/dL) 

for the United States population, aged 1 year and older, by selected demographic groups, 

National Health and Nutrition Examination Survey (NHANES), 1999-2000

Total, Age 1 and older

Sex

Male

Female

Race/Ethnicity

Black, non-Hispanic

Mexican American

White, non-Hispanic*

Age Group

1-5 years

6-11 years

12-19 years

20 years and older 

7,970

3,913

4,057

1,842

2,743

2,715

723

905

2,135

4,207

1.7

2.0

1.4

1.9

1.8

1.6

2.2

1.5

1.1

1.8

0.8

0.8

0.6

0.7

0.8

0.6

1.0

0.7

0.4

0.7

1.0

1.3

0.8

1.1

1.2

1.0

1.4

0.9

0.8

1.0

1.6

1.8

1.3

1.7

1.8

1.6

2.2

1.3

1.0

1.7

2.4

2.9

1.9

2.8

2.7

2.4

3.3

2.0

1.4

2.5

3.8

4.4

3.0

4.2

4.2

3.6

4.8

3.3

2.3

3.9

Sample Size Geometric Mean 10th 25th 50th 75th 90th

* Includes other racial/ethnic groups. 

Source: CDC. Second National Report on Human Exposure to Environmental Chemicals. 2003.

Selected Percentiles

** **

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-47

Indicator

Arsenic occurs in rock, soil, water, air, plants, and animals.

Exposure occurs when arsenic is further released into the environment through erosion, volcanic action, forest fires, or human

actions. Human activities involve its use in wood preservatives,

dyes, paints, paper production, and cement manufacturing.

Arsenic mining is also a source of human exposure (EPA, 2001a). 

Inorganic arsenic has been recognized as a human poison since

ancient times, and large oral doses (above 60,000 ppb in food or

water) can produce death. Lower levels of inorganic arsenic

(ranging from about 300 to 30,000 ppb in food, water, or

pharmaceuticals) may cause symptoms such as stomach ache,

nausea, vomiting, and diarrhea. Inorganic arsenic is a multi-site

human carcinogen. Populations with exposures above several

hundred ppb are reported to have increased risks of skin, bladder,

and lung cancer. The U.S. Department of Health and Human

Services (USDHHS) has determined that inorganic arsenic is a

known carcinogen. The International Agency for Research on

Cancer (IARC) had determined that inorganic arsenic is

carcinogenic to humans. Both the EPA and the National

Toxicology Program (NTP) have classified inorganic arsenic as a

known human carcinogen (ATSDR, 2001).

A large number of adverse noncarcinogenic effects have been

reported in humans. The most prominent are changes in the

skin, (e.g., hyperpigmentation and keratoses). Other effects

that have been reported include alterations in gastrointestinal,

cardiovascular, hematological, pulmonary, neurological,

immunological, and reproductive developmental function 

(NRC, 1999).

Children who are exposed to arsenic may have many of the same

effects as adults, including irritation of the stomach and intestines,

blood vessel damage, skin changes, and reduced nerve function.

Thus, all health effects observed in adults are of potential concern

in children (ATSDR, 2001).

What the Data Show

NHEXAS-Region 5. Arsenic levels in urine were measured for

approximately 202 participants during NHEXAS-Region 5. The

mean urine arsenic level was 29.32 micrograms per liter (μg/L),

while the median urine arsenic level was 3.65 μg/L. The mean

level is much higher than the median level, indicating that the

distribution is highly skewed to the higher values (Clayton, et

al., 1999).

NHANES. Future NHANES studies will include arsenic. Therefore,

NHANES will serve as the biomonitoring data source for arsenic.

When NHANES becomes the indicator data source for arsenic, 

the indicator will become a Category 1 indicator. 

Data Source 

NHEXAS, Environmental Protection Agency. (See Appendix B,

page B-33, for more information.) 

Urine arsenic level – Category 2
Mercury is a naturally occurring metal that is widespread and persistent in the environment. It is found in elemental form and in

various organic compounds and complexes. Methylmercury 

(one organic form of mercury) can accumulate up the food chain

in aquatic systems and lead to high concentrations of methylmercury in predatory fish. Consumption of contaminated fish is the

major source of human exposure to methylmercury in the U.S.

(NRC, 2000).

Methylmercury is rapidly absorbed from the gastrointestinal tract

and readily enters the brain, where it accumulates and is slowly

converted to inorganic mercury. A spectrum of adverse health

effects has been observed following methylmercury exposure,

with the severity depending largely on the magnitude of the

dose. The most severe effects reported in humans were seen

following high-dose poisoning episodes in Japan and Iraq. The

fetus is considered much more sensitive than the adult. Prenatal

exposures interfere with the growth and migration of neurons and

have the potential to cause irreversible damage to the developing

central nervous system. Infants exposed in utero during the Japan

and Iraqi episodes were born with severe disabilities, such as

mental retardation, seizure disorders, cerebral palsy, blindness,

and deafness. Chronic low-dose prenatal methylmercury exposure

from maternal consumption of fish has been associated with more

subtle end points of neurotoxicity (e.g., IQ deficits, abnormal

muscle tone, decrements in motor function, attention and

visuospatial performance) (NRC, 2000).

The human health effects of mercury are diverse and depend

upon the forms of mercury encountered and the severity and

length of exposure. Large acute exposures to elemental mercury

vapor can result in

lung damage. Lower

dose or chronic

inhalation may affect

the nervous system,

resulting in symptoms

such as weakness,

fatigue, weight loss,

gastrointestinal problems, and behavioral

and personality

changes. Organic

mercury is more toxic

than inorganic and

elemental mercury

(CDC, 2001c).

Health effects of

organic mercury include vision changes, sensory changes in the

limbs, cognitive disturbances, dermatitis, and muscle deterioration.

The developing nervous system of the fetus and infants is susceptible to the effects of methylmercury (CDC, 2003).

What the Data Show

NHANES 1999-2000. The blood mercury level reported in

NHANES is total blood mercury, including both organic and 

inorganic mercury. Mercury levels were measured in blood and

urine during NHANES 1999-2000 for 705 children aged 1-5

years, and 1,709 adult females aged 16-49. The mean blood

mercury level for males and females aged 1-5 years was 0.34

micrograms per liter (μg/L), and the mean blood mercury level for

adult females was 1.02 μg/L.

NHEXAS-Region 5. Mercury concentrations in human hair were

measured for 182 participants during NHEXAS-Region 5. The

mean mercury level in hair, annualized for seasonality, was 287

ppb. More people in older age categories have high levels of 

mercury in their hair. This increase in mercury level was found not

to be an effect of income level (Pellizari, et al., 1999).

Data Source

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-33, for more information.) 

Indicator

4-48 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

Blood mercury level – Category 1 

EPA’s Draft Report on the Environment 2003 ■ Technical Document

Sample Size Geometric Mean 10th 25th 50th 75th 90th

Age Group and Sex

Males/Females 1-5 years 705 0.3 <LOD <LOD 0.3 0.5 1.4

Males 387 0.3 <LOD <LOD 0.2 0.5 1.1 

Females 318 0.3 <LOD <LOD 0.2 0.8 1.6 

Females 16-49 years 1709 1.0 0.2 0.4 0.9 2.0 4.9

Race/Ethnicity (females 16-49 only) 

Mexican Americans 579 0.8 0.2 0.4 0.9 1.4 2.6 

Non-Hispanic blacks 370 1.4 0.3 0.6 1.3 2.6 4.8 

Non-Hispanic whites 588 0.9 <LOD 0.4 0.9 1.9 5.0

Exhibit 4-34: Geometric mean and selected percentiles of blood mercury concentrations (in μg/L) 

for males and females aged 1-5 years and females aged 16 to 49 years in the U.S. population, National Health and Nutrition Examination Survey (NHANES), 1999-2000

Selected Percentiles

<LOD means less than the limit of detection, which is 0.14 μg/L.

Source: CDC. Second National Report on Human Exposure to Environmental Chemicals. 2002.
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-49

Elemental cadmium is a metal that is usually found in nature

combined with other elements such as oxygen, chlorine, or sulfur.

Cadmium enters the environment from the weathering of rocks

and minerals that contain cadmium. Exposure to cadmium can

occur in occupations such as mining or electroplating, where

cadmium is used or produced. Cadmium exposure can also occur

from exposure to cigarette smoke (CDC, 2001c). 

Cadmium and its compounds are toxic. Once absorbed into the

human body, cadmium can remain for decades. Exposure to

cadmium for many years may result in cadmium accumulation in

the kidneys and serious kidney damage. Chronic ingestion of

cadmium has resulted in osteomalacia, a bone disorder similar to

rickets. Acute airborne exposure, as occurs from welding on

cadmium-alloy metals, can result in swelling (edema) and scarring

(fibrosis) of the lungs (CDC, 2003).

What the Data Show

NHANES 1999-2000. This survey measured blood cadmium

levels in people 1 year and older, and urine cadmium levels in a

sample of people 6 years and older. Recent advances in analytical

chemistry have made it possible to measure cadmium in very small

amounts in blood and urine. Finding a measurable amount of

cadmium in the blood or urine does not mean that the level of

cadmium causes an adverse health effect (CDC, 2001c). The

blood cadmium biomonitoring measurements are similar among

males and females as well as among the racial or ethnic groups

sampled. Exhibit 4-35 shows that blood levels were higher among

people 20 years of age or older than for people younger than 20

years of age (CDC, 2001c). The mean urine cadmium level was

0.3 μg/L (CDC, 2001c).

Data Source

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-34, for more information.) 

Indicator Blood cadmium level – Category 1

Sample Size

Selected Percentiles

10th 25th 50th 75th 90th

Total, Age 1 and Older

Sex

 Male

 Female

Race/Ethnicity

 Black, non-Hispanic

 Mexican American

 White, non-Hispanic*

Age Group

 1-5 years

 6-11 years

 12-19 years

 20+ years

7,970

3,913

4,057

1,842

2,743

2,715

723

905

2,135

4,207

<LOD 

<LOD**

<LOD**

<LOD**

<LOD**

<LOD**

<LOD**

<LOD**

<LOD**

<LOD**

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

0.3

0.4

0.3

0.3

0.4

0.4

<LOD

<LOD

0.3

0.4

0.6

0.6

0.6

0.6

0.4

0.5

0.3

0.3

0.3

0.6

1.0

1.0

1.0

1.0

0.7

1.0

0.4

0.4

0.8

1.0

* Includes other racial/ethnic groups. <LOD= Less than the limit of detection of the analytical method.

Source: CDC. Second National Report on Human Exposure to Environmental Chemicals. 2003.

Exhibit 4-35: Geometric mean and selected percentiles of blood cadmium concentrations (in μg/L) 

for the United States population, aged 1 year and older, by selected demographic groups, 

National Health and Nutrition Examination Survey (NHANES), 1999-2000

Geometric Mean

0.4

0.4

0.4

0.4

0.4

0.4

**

**

0.3

0.5
Cotinine can be measured in blood, urine, saliva, and hair. 

Non-smokers exposed to ETS have cotinine levels of less than 1

nanogram per milliliter (ng/mL), with heavy exposure to ETS 

producing levels in the 1 to 15 ng/mL range. Active smokers

almost always have levels higher than 15 ng/mL (CDC, 2001c).

What the Data Show

NHANES 1999-2000. Exhibit 4-36 presents data for the U.S.

non-smoking population aged 3 years and older. Males have 

higher levels than females, and people aged 20 years and older

have lower levels than those younger than 20 years of age. 

Levels for non-Hispanic African Americans are higher than for

other ethnic groups (CDC, 2001c).

NHANES III (1988-1991). As part of NHANES III, CDC

determined that the median level of cotinine among non-smokers

in the U.S. was 0.20 ng/mL (Pirkle, et al., 1996, in CDC, 2001c).

Results from NHANES 1999-2000 show that the median cotinine

level has decreased to less than 0.050 ng/mL—more than a 75

percent decrease from NHANES III to NHANES 1999-2000 (CDC,

2001c). NHANES III (1988-1991) provided the first evidence from

a national study that serum cotinine levels are higher among Black

smokers than among White or Mexican American smokers at all

levels of cigarette smoking (Caraballo, et al., 1998).

Data Source 

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-34, for more information.) 

Indicator

4-50 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

Blood cotinine level - Category 1 

Sample Size

Selected Percentiles

10th 25th 50th 75th 90th

Total, Age 3 years and Older

Sex

Male

Female

Race/Ethnicity

Black, non-Hispanic*

Mexican American

White, non-Hispanic**

Age Group

3-11 years

12-19 years

20+ years

5,999

2,789

3,210

1,333

2,242

1,949

1,174

1,773

3,052

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

<LOD

0.06

0.08

<LOD

0.13

<LOD

0.05

0.11

0.11

<LOD

0.24

0.30

0.18

0.50

0.14

0.21

0.50

0.54

0.17

1.02

1.20

0.85

1.43

0.51

0.95

1.88

1.65

0.63

* Research in progress to determine whether levels for black, non-Hispanic people may be affected by biological factors.

** Includes other racial/ethnic groups.

<LOD= Less than the limit of detection of 0.05 ng/mL in serum.

Source: CDC. Second National Report on Human Exposure to Environmental Chemicals. 2003.

Exhibit 4-36: Selected percentiles of serum cotinine concentrations (in ng/mL) for the United States non-smoking population, 

aged 3 years and older, National Health and Nutrition Examination Survey (NHANES), 1999-2000

4.4.4 What is the level of exposure

to cotinine?

Environmental tobacco smoke (ETS) is a dynamic, complex mixture

of more than 4,000 chemicals found in both vapor and particle

phases. Many of these chemicals are known toxic or carcinogenic

agents (ALA, et al., 1994). The EPA has classified ETS as a known

human carcinogen and estimates that it is responsible for approximately 3,000 lung cancer deaths per year among non-smokers in

the U.S. (EPA, NCEA, December 1992).

Cotinine is a major metabolic product of nicotine and is currently

regarded as the best biomarker for exposure of active smokers and

non-smokers to ETS. Measuring cotinine is preferred over measuring

nicotine because, although both are specific for exposure to tobacco, cotinine remains in the body much longer than nicotine. 

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-51

Biomonitoring data for volatile compounds are difficult to obtain

because these compounds do not persist for very long in the

body. For this reason, biomonitoring data are indicative of recent

exposure only. Only relatively older sources of data, NHEXAS and

NHANES III, are available for the body burden of VOCs.

What the Data Show

NHEXAS-Region 5. Blood levels of four VOCs were obtained for

participants in NHEXAS-Region 5. The four compounds were

benzene, chloroform, tetrachloroethylene (PERC), and

trichloroethylene (TCE). The mean level of benzene measured in

blood was 0.07 μg/L. The mean level of chloroform was 0.07 μ/L.

The mean level of PERC was 0.21 μg/L. The mean level of TCE

was below the limit of detection (Clayton, et al., 1999). 

NHANES III (1988-1994). Blood samples were analyzed for the

presence of VOCs during NHANES III. NHANES III was conducted

on a nationwide probability sample of approximately 33,994

persons aged 2 months or older. Of these, an exposure

questionnaire was administered and blood samples analyzed for

VOCs in a convenience sample of 1,018 adult participants aged

20 to 59 years. Toluene, styrene, and benzene were present in the

blood of more than 75 percent of the participants. Analysis of

this and other data collected during NHANES III shows a strong

association between lifetime cigarette smoking and toluene,

benzene, and styrene levels (Churchill and Kaye, 2001).

Data Source 

NHANES III (1988-1994), National Center for Health Statistics.

(See Appendix B, page B-34, for more information.) 

Indicator Blood VOC levels – Category 1

4.4.5 What is the level of exposure

to volatile organic compounds?

In addition to the health effects attributed to VOCs themselves,

VOCs are also chemical compounds that contribute significantly to

the formation of ground-level ozone (smog) when released to the air.

Exposure to ground-level ozone can damage lung tissue and cause

serious respiratory illness. (For additional information on VOCs in

the environment, see Chapter 1, Cleaner Air.) 

4.4.6 What is the level of 

exposure to pesticides?

Organophosphate pesticides account for about half of the insecticides used in the U.S. Organophosphate pesticides are active against

a broad spectrum of insects and are used on food crops as well as in

residential and commercial buildings and on ornamental plants and

lawns. Exposure to these pesticides occurs primarily from ingestion

of food products or from residential use (CDC, 2001c).

The mechanism of toxicity of the organophosphate pesticides is to

inhibit the enzyme that breaks down acetylcholine, which transfers

nerve impulses between nerve cells or from a nerve cell to other

types of cells, such as muscle cells. This leads to a buildup of 

acetylcholine, which overstimulates muscles, causing symptoms such

as weakness and paralysis (CDC, 2001c). (For additional information

on pesticides in the environment, see Chapter 1, Cleaner Air;

Chapter 2, Purer Water; and Chapter 3, Better Protected Land.)
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Pesticides biomonitoring data are obtained by measuring the

chemicals that pesticides are broken down into in the body.

Measurement of these pesticide metabolites reflects exposure to

pesticides that has occurred predominantly in the last few days

(CDC, 2001c). The reason is that these metabolites persist within

the body for only a short time.

Presently, national biomonitoring data are available primarily for

organophosphate pesticides. Future studies may provide

additional indicators for non-organophosphate pesticides, such as

carbamates and persistent pesticides.

What the Data Show

NHANES 1999-2000. Urine levels of organophosphate

pesticide metabolites were measured in a subsample of NHANES

participants 6 through 59 years of age who were selected to be

representative of the U.S. population. Finding a measurable

amount of one or more metabolites in urine does not mean that

the level of the organophosphate causes an adverse health

effect. Whether organophosphate pesticides at the levels of

metabolites reported during NHANES 1999-2000 are a cause

for health concern is not known (CDC, 2001c). Exhibit 4-37

shows the amount of each metabolite in urine reported in

NHANES 1999-2000. 

NHEXAS-MD. Urine levels of metabolites of some common

pesticides were measured during NHEXAS-MD. 1-naphthol

(1NAP) is a urinary metabolite of both carbaryl and naphthalene.

The mean urine level of 1NAP measured for 338 participants was

33.7 μg/L. 3,5,6-trichloro-2-pyridinol (TCPY) is the major

metabolite in urine of the pesticides chlorpyrifos, chlorpyrifosmethyl, and triclopyr. The mean urine level of TCPY measured for

346 participants was 6.8 μg/L. Malathion dicarboxylic acid

(MDA) is a principal metabolite of malathion, an organophosphate

pesticide used against insects. The mean urine level for MDA

measured during NHEXAS-MD was below the level of detection.

Atrazine mercapturate (AM) is a urinary metabolite of atrazine, a

widely used herbicide in the U.S. The mean urine level for AM

measured during NHEXAS-MD was below the level of detection

(MacIntosh, et al., 1999).

Data Source 

NHANES 1999-2000,

National Center for Health

Statistics. (See Appendix B,

page B-35, for more 

information.) 

Indicator Urine organophosphate levels to indicate pesticides – Category 1

4-52 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

Sample

Size

Geometric

Mean

Selected Percentiles

(95% confidence interval)

10th 25th 50th 75th 90th

Dimethylphosphate

μg/L of urine 1,949 NC < LOD < LOD 0.74 2.80 7.90 

μg/g of creatinine* 1,949 NC < LOD** < LOD 0.81 2.93 8.46

Dimethylthiophosphate

μg/L of urine 1,948 1.82 < LOD < LOD 2.70 10.0 38.0 

μg/g of creatinine* 1,948 1.64 < LOD* < LOD 2.12 9.57 32.0

Dimethyldithiophosphate

μg/L of urine 1,949 NC < LOD < LOD < LOD 2.30 12.0 

μg/g of creatinine* 1,949 NC < LOD** < LOD < LOD 1.86 10.1

Diethylphosphate

μg/L of urine 1,949 1.03 < LOD** < LOD 1.20 3.10 7.50 

μg/g of creatinine* 1,949 0.92 < LOD** < LOD 0.93 2.73 7.94

Diethylthiophosphate

μg/L of urine 1,949 NC < LOD** < LOD 0.49 0.76 1.3 

μg/g of creatinine* 1,949 NC < LOD** < LOD 0.25 0.71 1.7

Diethyldithiophosphate

μg/L of urine 1,949 NC < LOD** < LOD 0.08 0.20 0.47 

μg/g of creatinine* 1,949 NC < LOD** < LOD 0.07 0.20 0.55

Exhibit 4-37: Geometric mean and selected percentiles of selected pesticide metabolite urine concentrations 

and creatinine-adjusted levels for the United States population aged 6-59 years, National 

Health and Nutrition Examination Survey (NHANES), 1999-2000

μg per gram of creatinine in urine.

<LOD= Less than the limit of detection for the analytical method.

NC=Not calculated - Proportion of results below limit of detection was too high to provide a valid result.
Technical Document ■ EPA’s Draft Report on the Environment 2003

4.4.7 What is the level of exposure

to persistent organic pollutants?

Persistent organic pollutants (POPs) are manmade organic chemicals

that remain in the environment for long periods of time. Some POPs

are toxic; others are not. Toxic POPs are of a special concern

because they often remain toxic for decades or longer. The more

persistent a toxic chemical is, the greater the probability for human

exposure over time.

POPs have been linked to adverse health effects such as cancer, 

nervous system damage, reproductive disorders, and disruption of

the immune system in both human and animals. POPs released in one

part of the world can travel to regions far from their place of origin,

because they circulate globally long after their release into the

atmosphere, oceans, and other pathways (EPA, 2001b).

Under the United Nations Environment Program, the international

community has identified 12 chemicals as primary POPs. These

chemicals include certain insecticides such as dichlorodiphenyltrichloroethane (DDT) and chlordane, which were once commonly

used to control pests, and polychlorinated biphenyls (PCBs), which

were used in hundreds of commercial applications for electrical, 

heat transfer, and hydraulic equipment, and in plasticizers in paints,

plastics, and rubber products.

The 12 chemicals targeted by EPA as POPs are the pesticides aldrin,

chlordane, DDT, mirex, toxaphene, dieldrin, endrin, and heptachlor;

hexachlorobenzene, an industrial chemical; PCBs; polychlorinated

dibenzo-p-dioxins (dioxins); and polychlorinated dibenzo-p-furans

(furans) (EPA, 2001b).

The following discussion of human exposure to POPs is derived from

the Second National Report on Human Exposure to Environmental

Chemicals, published in January 2003 by the CDC National Center

for Environmental Health (CDC, 2003). Four of the 12 POPs are not

addressed by the CDC report and are therefore not addressed

specifically in this chapter. These four chemicals are aldrin,

toxaphene, dieldrin, and endrin. The remaining POPs were not

evaluated for indicators at this time but EPA anticipates that these

chemicals will become indicators in the future.

Chlordane and Heptachlor

In 1988, EPA banned the use and production of chlordane in the

U.S. Chlordane is an organochlorine pesticide that was applied in

and around buildings to eliminate termites and was also used as an

agricultural and lawn pesticide. The technical grade of chlordane

consists of a group of related chemicals, including heptachlor, 

cis-chlordane, trans-chlordane, and trans-nonachlor. Note that

heptachlor was also used individually as a pesticide separate from

chlordane. However, pesticide applications were mostly made with

technical grade chlordane and therefore chlordane is the main form

of heptachlor exposure.

Within the body, chlordane is metabolized to oxychlordane and

heptachlor is metabolized to heptachlor epoxide. Human exposure to

chlordane and heptachlor is determined by measuring the blood

serum concentrations of oxychlordane, trans-nonachlor, and

heptachlor epoxide. However, generally recognized guidelines for

serum levels of these metabolites have not been established. 

The NHANES 1999-2000 mean levels of oxychlordane and

heptachlor epoxide in the overall population were below the lipidadjusted level of detection, which averaged 7.4 ng/g of lipid. The

NHANES II (1976-1980) 95th percentile level was about twice the

NHANES 1999-2000 level for oxychlordane and trans-nonachlor.

DDT

DDT was initially used by the military during the 1940s to control

mosquitoes that carried vector-borne diseases such as malaria. EPA

banned the use of DDT in the U.S. in 1973. DDT, however, is still

produced and used in other countries. 

For the general population, food is the most common pathway of

exposure. Diets that involve large amounts of Great Lakes fish will

increase an individual’s exposure to DDT. Food intake of DDT has

decreased since the 1950s; however, food imported to the U.S. may

have DDT contamination, especially food imported from tropical

regions where DDT is used in the greatest quantities.

Dichlorodiphenyldichloroethylene (DDE) (more persistent than

DDT) is a major DDT metabolite that can be produced in people 

or in the environment. DDT in the human body reflects either a 

relatively recent exposure or a cumulative past exposure over time. 

A high DDT-to-DDE ratio may indicate a recent exposure, and a low

DDT-to-DDE ratio may indicate an exposure in the more distant past.

The NHANES 1999-2000 95th percentile levels (lipid-adjusted

serum) for DDT and DDE in the overall population range from 5-fold

to 15-fold lower than levels detected in a non-random subsample of

NHANES II (1976-1980). These decreases in the U.S. levels are 

consistent with the decreased use and manufacture of these chemicals. Also, within NHANES 1999-2000, the group aged 12 to 19

years had DDE levels 2-fold lower than the group 20 years and older.

Hexachlorobenzene (HCB)

Hexachlorobenzene is a persistent, bioaccumulative, and toxic pollutant (EPA, 2003b). It was commonly used as a pesticide until 1965,

as a fungicide to protect wheat seeds, and for a variety of industrial

purposes, including rubber, aluminum, and dye production and wood

preservation (EPA, 2003c). In 1984, EPA canceled its registered use.

There currently are no commercial uses of HCB in the U.S. (EPA,

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-53
EPA’s Draft Report on the Environment 2003 ■ Technical Document

2003c); however, HCB is still formed as a by-product during the

manufacture of other chemicals (mainly solvents) and pesticides. 

Human exposure to HCB can occur through work in or proximity to

chemical manufacturing sites where it is formed as a by-product or

to waste facilities where it is disposed. People also can be exposed

by consuming foods tainted with hexachlorobenzene (EPA, 2003c).

EPA has set the maximum contaminant level (MCL) for

hexachlorobenzene in drinking water at 1 part per billion. If HCB

levels exceed this level, the water supplier must notify the public

(EPA, 2002g). 

HCB has been found to potentially cause skin lesions and nerve and

liver damage when people are exposed at levels above the MCL for

relatively short periods (EPA, 2002g). Lifetime exposure at levels

above the MCL can damage the liver and kidneys and cause

reproductive effects, benign tumors of endocrine glands, and cancer

(EPA, 2002g).

Epidemiologic studies of persons orally exposed to HCB have not

shown an increased cancer incidence. However, EPA has classified

HCB as a probable human carcinogen (Group B2) based on animal

studies that have reported cancer of the liver, thyroid, and kidney

from oral HCB exposure. Very few inhalation data are available 

(EPA, 2003c). 

Generally recognized guidelines for HCB serum levels are not

available. HCB was detected in 0.6 percent of people during the

1999-2000 NHANES study. Finding detectable amounts does not

mean that those levels produce adverse health effects. HCB has a

residence time of approximately 15 years in body fat.

PCBs

PCBs are chlorinated aromatic hydrocarbon chemicals that were

once used as electrical insulating and heat exchange fluids. Within

the U.S., peak production occurred in the early 1970s and

production within the U.S. was banned in 1979. Concern over these

chemicals remains high because they are still released into the

environment.

Sources of exposure for the general population include release of

PCBs from waste sites and from fires involving transformers and

capacitors; ingestion of foods containing PCBs due to contamination

of animal feeds; migration from packaging materials; and

accumulation in the fatty tissues of livestock. PCBs are found at

higher concentrations in fatty foods. In occupational settings,

workers can be exposed to PCBs from remediation activities at

hazardous waste sites and from the repair of transformers,

capacitors, and hydraulic systems (CDC, 2003a). 

The Food and Drug Administration and the Occupational Safety and

Health Administration have developed criteria for allowable levels of

PCBs in foods and the workplace. EPA has established criteria for

water and for the storage and removal of PCB-contaminated wastes.

Overall, there are three categories of at least 25 different PCB

compounds (termed congeners) as determined by molecular

structure. Congeners are closely related chemical compounds. The

three categories are coplanar PCBs, mono-ortho substituted PCBs,

and other PCBs. The significance of these categories is that coplanar

and mono-ortho substituted PCBs have health effects similar to

dioxins. Overall, the human health effects of PCBs include liver

disorders, elevated lipids, and gastrointestinal cancers 

(CDC, 2003a). 

The detection of serum PCBs can reflect either recent or past

exposures to PCBs. Those PCBs with higher degrees of chlorination

persist in the human body from several months to years after

exposure. In the NHANES 1999-2000 subsample, the frequency 

of detection of the eight mono-ortho substituted PCBs ranged from

2 percent to 47 percent. Finding detectable amounts does not

mean that those levels result in adverse health effects. (For

additional information on PCBs in the environment, see Chapter 2,

Purer Water; Chapter 3, Better Protected Land; and Chapter 5,

Ecological Condition.)

Polychlorinated Dibenzo-p-Dioxins (Dioxins) and

Polychlorinated Dibenzo-p-Furans (Furans)

Dioxins and furans are similar classes of chlorinated aromatic

chemicals usually generated as pollutants or by-products. They have

no commercial or natural use. Processes that result in their

generation include the incineration of waste, the production of pulp

and paper, and the synthesis of various manmade chemicals. Releases

from industrial sources have decreased by approximately 80 percent

since the 1980s. The largest releases of dioxins and furans today are

the open burning of household and municipal trash, landfill fires, and

agricultural and forest fires. In the environment, dioxins and furans

occur as a mixture of about 20 congeners (i.e., closely related

chemical compounds). 

Human exposure occurs primarily through foods that are

contaminated with dioxins and furans. Food contamination occurs

due to the accumulation of these chemicals in the food chain and in

high-fat foods, such as dairy products, eggs, animal fats, and some

types of fish. People have also been exposed through industrial

accidents, the burning of PCBs, and through the spraying of

contaminated herbicides such as Agent Orange. Workplace

exposures are rare and generally recognized standards for external

exposure have not been established.

Human health effects associated with dioxins and furans are wideranging. Given that the exposure of the general population occurs as

exposure to a mixture of congeners, the effects of individual

congeners are difficult to determine. Overall, associated dioxin and

EPA’s Draft Report on the Environment 2003 ■ Technical Document

4-54 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health
Technical Document ■ EPA’s Draft Report on the Environment 2003

furan health effects include liver disorders, fetal injury, porphyria,

elevated lipid levels, chloracne, hormonal changes, neurologic

damage, and immunogic changes. The dioxin cogener termed TCDD

is the most toxic form of dioxin and it is classified as a known human

carcinogen.

It is estimated that human serum lipid-based levels of overall dioxins

and furans have decreased by 80 percent since the 1980s and the

low NHANES 1999-2000 values support that estimation. The levels

detected via NHANES 1999-2000 are far below those associated

with occupational and unintentional exposures that resulted in

human health effects. 

Further, the NHANES 1999-2000 subsample reveals that the more

highly chlorinated dioxin and furan cogeners are the main

contributors to the human body burden. The higher concentrations

in human tissues of these cogeners are due to their greater presence

in the food chain, resistance to metabolic breakdown, and greater

solubility in body fat. Half-lives for all the dioxin and furan cogeners

range from 3 to 19 years and TCDD is estimated to be 7 years.

4.4.8 What are the trends in

exposure to environmental

pollutants for children?

Children may be affected by environmental pollutants quite

differently than adults, both because children may be more highly

exposed to pollutants and because they may be more vulnerable to

the toxic effects of pollutants. Children generally eat more food,

drink more water, and breathe more air relative to their size than do

adults, and consequently may be exposed to relatively higher

amounts of pollutants. Also, unlike adults, children’s normal activities,

such as putting their hands in their months or playing on the

ground, create greater opportunities for exposures to pollutants. In

addition, environmental pollutants may affect children

disproportionately because their organ systems are still developing

and therefore may be more susceptible (EPA, December 2000). This

section presents three environmental pollutants that represent

exposures of concern to children: lead, mercury, and cotinine.

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-55

Infants, children, and fetuses are more vulnerable to the effects of

lead because the blood-brain barrier is not fully developed

(Nadakavukaren, 2000). Thus, a smaller amount of lead will have

a greater effect in children than in adults. In addition, ingested

lead is more readily absorbed into a child’s bloodstream. Children

absorb 40 percent of ingested lead into the bloodstream, while

adults absorb only 10 percent. Because of lead’s adverse effects

on cognitive development, CDC has defined an elevated blood

lead level as equal to or greater than 10 μg/dL for children under

6 years of age (CDC, 2001c). 

What the Data Show

In NHANES III (1988-1994), the mean blood lead levels for children ages 1 to 5 declined from 3.6 μg/dL in Phase 1 (1988 to

1991) to 2.7 μg/dL in Phase 2 (1991 to 1994). Over the same

time interval, the percentage of children aged 1 to 5 years with

elevated blood lead levels decreased from 8.6 percent to 4.4 percent (Pirkle, 1998). In NHANES 1999-2000, the geometric median blood lead level for children 1 to 5 years old is 2.2 μg/dL. The

median blood lead level for children 6 to 11 years old is 1.5 μg/dL

(see exhibit 4-8 in this chapter).

Data Source 

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-35, for more information.) 

Indicator Blood lead level in children – Category 1
EPA’s Draft Report on the Environment 2003 ■ Technical Document

Children may be more highly exposed to mercury and may be

more vulnerable to its toxic effects. The health effects of mercury

are diverse and can include developmental and neurological

effects in children. 

What the Data Show

Extremely limited information has been available about children’s

exposure to mercury and how it relates to levels in adults. Exhibit

4-38 shows that the geometric mean of blood mercury levels

among U.S. children measured in NHANES 1999-2000 was 0.34

μg/L. The geometric mean of blood mercury levels of women of

childbearing age was 1.02 μg/L. Levels among women of childbearing age are particularly important because they reflect levels

of mercury to which the fetus is exposed (NRC, 2000). During a

toxicological review of mercury levels, the National Research

Council estimated a benchmark dose, which was an estimate of a

methylmercury exposure to the fetus, associated with an increase

in abnormal scores on cognitive function tests among children.

The lower 95 percent confidence bound on the benchmark dose

was 58 μg/L (NRC, 2000). To account for uncertainties in exposure measures and variability in individual response to toxic effects

of mercury, the NRC recommended an uncertainty factor of 10 to

calculate a reference dose. EPA published its final reference dose

of 5.8 μg/L, agreeing with NRC. Ninety percent of children 1 to 5

years old and women of childbearing age are below this level

(CDC, 2001c). 

Data Source 

NHANES III (1999),

National Center for

Health Statistics. 

(See Appendix B, 

page B-35, for 

more information.) 

Indicator

4-56 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

Blood mercury level in children – Category 1

Indicator Blood cotinine level in children – Category 1

Exhibit 4-38: Geometric mean and selected percentiles of total blood mercury concentrations (in μg/L) 

for United States children aged 1-5 years, and women aged 16-49 years, 

National Health and Nutrition Examination Survey (NHANES), 1999-2000

Children, aged

1-5 years, males

and females

Females, 16-49 years

705

1,709

0.34

1.02

<LOD 

0.20

<LOD 

0.40

0.30

0.90

0.50

2.00

1.40

4.90

Sample Size Geometric Mean 10th 25th 50th 75th 90th

 

<LOD = below the limit of detection of the analytical method of 0.14 μg/dL blood.

Source: CDC. Second National Report on Human Exposure to Environmental Chemicals. 2003.

Selected Percentiles

Children are at particular risk from ETS, which may exacerbate

asthma among susceptible children and also greatly increase the

risk for lower respiratory-tract illness, such as bronchitis and

pneumonia, among young children (CDC, 2001c). NHANES

1999-2000 data show that people younger than 20 years have

higher cotinine levels than people 20 years and older (CDC,

2003). (See Exhibit 4-35 located in Section 4.4.4.) Blood

cotinine level is an indicator of exposure to ETS. During NHANES

1999-2000, the average blood cotinine level for children aged 3

to 11 years was 0.11 ng/mL. This level was the same for children

in the 12 to 19 years subgroup (CDC, 2003).

For the general population, as part of NHANES III (1988-1991),

CDC determined that the median serum level (50th percentile) of

cotinine among non-smokers in the U.S. was 0.20 ng/mL. As

determined during NHANES 1999-2000, the median cotinine

level decreased to 0.059 ng/mL, a 70 percent decrease. This

reduction suggest a marketed decrease in exposure of the general

U.S. population to ETS since the 1988-1991 period. Further,

compared with the results for the 1988-1991 period, NHANES

1999-2000 reveals that cotinine levels declined in each of the

population groups defined by age, sex, and race/ethnicity 

(CDC, 2003).

Data Source 

NHANES 1999-2000, National Center for Health Statistics. 

(See Appendix B, page B-36, for more information.) 
Technical Document ■ EPA’s Draft Report on the Environment 2003

4.4.9 Pollutants for Which Biomonitoring Data 

Are Not Available

As mentioned above, biomonitoring is an emerging field. More 

biomonitoring indicators are available now than a few years ago. Still,

there are many environmental pollutants for which biomonitoring

techniques are not available or feasible. These include radiation, air

pollutants (except for lead), biological pollutants, and disinfection

by-products. Biomonitoring efforts have begun recently for disinfection by-products; however, at this time data are not sufficient to

develop indicators for these pollutants. All these pollutants are of

concern because exposure is widespread. For these pollutants, 

exposure assessments currently rely primarily on ambient data. 

What is the level of exposure to

radiation?

Radiation is energy given off by atoms in the form of particles or

electromagnetic rays. There are actually many different types of 

electromagnetic radiation that have a range of energy levels. They

form the electromagnetic spectrum and include radio and micro

waves, heat, light, and x-rays (EPA, 2002w).

Radiation that has enough energy to move atoms in a molecule

around or cause them to vibrate, but not enough to change them

chemically, is referred to as "non-ionizing radiation." Examples of 

this kind of radiation are sound waves, visible light, and microwaves

(EPA, 2002y). Non-ionizing radiation can be used for some common

tasks, such as using microwave radiation for telecommunications and

heating food, infrared radiation for producing warmth, and radio

waves for broadcasting (EPA, 2002y). Non-ionizing radiation has 

relatively long wavelengths and low frequencies, in the range of 1

million to 10 billion Hertz (EPA, 2002y).

Radiation that has enough energy to actually break chemical bonds

or strip electrons away from atoms is called "ionizing radiation

(EPA, 2002x)." Radioactive materials that decay spontaneously

produce ionizing radiation. Any living tissue in the human body can

be damaged by ionizing radiation. The body attempts to repair the

damage, but sometimes the damage is too severe or widespread,

or mistakes are made in the natural repair process. The most 

common forms of ionizing radiation are alpha and beta particles, or

gamma and X-rays (EPA, 2002x). Ionizing radiation has very short

wavelengths, and very high frequencies, in the range of 100 billion

billion Hertz (EPA, 2002y). This is the type of radiation that 

people usually think of as 'radiation.' Ionizing radiation can be

used to generate electric power, to kill cancer cells, and in many

manufacturing processes (EPA, 2002y). 

Radiation can affect the body in a number of ways, and the adverse

health consequences of exposure may not be seen for many years.

These adverse health effects can

range from mild effects, such as

skin reddening, to serious effects

such as cancer and death,

depending on the amount of radiation absorbed by the body (the

dose), the type of radiation, the

route of exposure, and the length

of time a person is exposed.

Exposure to very large doses of

radiation may cause death within a

few days or months. Exposure to

lower doses of radiation may lead

to an increased risk of developing

cancer or other adverse health

effects (CDC, 2003).

There are three basic pathways for

radiation exposure. These are

inhalation, ingestion, and direct

exposure. Each of the different

routes, or pathways, by which

people can be exposed to radiation result in exposure to different

parts of the body (EPA, 2002z).

Exposure by the inhalation 

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-57

Sample

Size

Geometric

Mean

Selected Percentiles

(95% confidence interval)

10th 25th 50th 75th 90th

Exhibit 4-39: EPA map of radon zones in the United States

Zone 1 (4pCi/L)

Zone 2 (2-4pCi/L)

Zone 3 (2pCi/L)

Source: Modified from EPA, Office of Air and Radiation. EPA Map of Radon Zones. April 2003. (May 2, 2003; http://www.epa.gov/iaq/radon/zonemap.html).
4-58 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends Chapter 4 - Human Health

pathway occurs when people breathe radioactive materials into the

lungs. The chief concerns are radioactively contaminated dust,

smoke, or gaseous radionuclides such as radon (EPA, 2002z). Radon

is a colorless, tasteless, and odorless gas that comes from the decay

of uranium found in nearly all soils. Levels of radon vary throughout

the country. Radon usually moves upward from the ground and

migrates into homes and other buildings through cracks and other

holes in their foundations. The buildings trap radon inside, where it

accumulates and may become a health hazard if the building is not

properly ventilated (EPA, June 2000; EPA, 2002b).

No biomonitoring data are feasible for national estimates of exposure

to radon. Data for average national indoor and outdoor radon levels

are available, but unlike biomonitoring data, these data do not

represent the amount of radon found in human tissue. Rather, they

are the levels of radon measured in the air. Radon levels vary

throughout the U.S. Exhibit 4-39 shows the distribution of radon

levels throughout the country (EPA, 2003d). Based on a national

residential radon survey completed in 1991, the average indoor

radon level is 1.3 picocuries per liter in the U.S. The average outdoor

level is about 0.4 picocuries per liter (EPA, 2002b). 

Radiation exposure by the ingestion pathway occurs when someone

swallows radioactive materials. For example, exposure by ingestion

can occur when drinking water becomes radioactively contaminated,

or when food is grown in contaminated soil. Alpha and beta emitting

radionuclides are of most concern for ingested radioactive materials.

They release large amounts of energy directly to tissue, causing DNA

and other cell damage (EPA, 2002z). 

The third pathway of concern is direct or external exposure from

radioactive material. The concern about exposure to different kinds

of radiation varies by the particular type of particle or wave that is

being emitted. Alpha particles cannot penetrate the outer layer of

skin, but open wounds may pose a risk. Beta particles can burn the

skin in some cases, or damage eyes. Greatest concern is about

gamma radiation. Different radionuclides emit gamma rays of different

strength, but gamma rays can travel long distances and penetrate

entirely through the body. Gamma rays can be slowed by dense

material (shielding), such as lead, and can be stopped if the material

is thick enough. Examples of shielding are containers; protective

clothing, such as a lead apron; and soil covering buried radioactive

materials (EPA, 2002z).

Radiation can occur from man-made sources such as x-ray machines;

or from natural sources such as the sun and outer space, and from

some radioactive materials such as uranium in soil (CDC, 2003).

About 80 percent of human exposure to radiation is from naturally

occurring forms of radiation. The remaining 20 percent of exposure

is to manmade radiation sources, primarily medical x-rays (CDC,

2003).

Radiation doses that people receive are measured in units called

"rem (CDC, 2003)." Most people receive about 300 mrem every

year from natural background sources of radiation, primarily radon.

Health physicists generally agree on limiting a person's exposure

beyond background radiation to about 100 millirem (mrem) per year

from all sources. Exceptions are occupational, medical or accidental

exposures. (Medical X-rays generally deliver less than 10 mrem). EPA

and other regulatory agencies generally limit exposures from specific

sources to the public to levels well under 100 mrem. This is far below

the exposure levels that cause acute health effects (EPA, 2002x).

For additional information on radiation in the environment, see

Chapter 1, Cleaner Air.

What is the level of exposure to air

pollutants?

Criteria air pollutants are common air pollutants comprised of ozone,

nitrogen dioxide, carbon monoxide, sulfur dioxide, lead, and

particulate matter. The health effects associated with criteria air

pollutants are discussed in Chapter 1, Cleaner Air, Section 1.1.3.

Ozone is the result of a chemical reaction in the atmosphere between

VOCs and nitrogen oxides. Nitrogen dioxide comes from the burning

of gasoline, natural gas, coal, and oil. Cars are an important source of

nitrogen dioxide.

Carbon monoxide comes from the burning of gasoline, natural gas,

coal, and oil. Carbon monoxide reduces the ability of blood to bring

oxygen to body cells and tissues. Carbon monoxide may be

particularly hazardous to people who have heart or circulatory

problems.

Particulate matter (PM) can be emitted directly into the atmosphere,

such as dust from roads or elemental carbon (soot) from wood

combustion. PM can also be formed in the atmosphere from primary

gaseous emissions such as sulfur dioxide and nitrogen oxides, which

come from power plants, industrial facilities, automobiles, and other

types of combustion sources.

The primary source of sulfur dioxide is the burning of coal and oil,

especially high-sulfur coal from the eastern U.S., and industrial

processes (paper, metals). The primary source of lead in ambient air

was leaded gasoline, which has been phased out in the U.S. Other

sources of lead include paint, smelters, and the manufacture of lead

storage batteries. Major health effects associated with lead are

discussed in Section 4.1.

Except for lead, biomonitoring methods are not available or feasible

for the remaining criteria air pollutants. Data for average national

ambient air pollutant levels are available (see Chapter 1, Cleaner Air).

Research on actual intake measures of air pollutants and their relationship to ambient levels as measured by monitoring networks is

under way. Many other studies have found links between air 

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.4 Measuring Exposure to Environmental Pollution: Indicators and Trends 4-59

pollutants and disease, as noted in the discussion of diseases and

their relationships to environmental pollutants (see Section 4.1).

What is the level of exposure to

biological pollutants?

Biological pollutants are or were living organisms. In addition to

arthropod-borne, foodborne, or waterborne disease discussed

previously, other biological agents can promote poor indoor air

quality and may be a major cause of days lost from work or school

and of doctor and hospital visits. Some can even damage surfaces

inside and outside the residence. Some common indoor biological

pollutants include: animal dander (minute scales from hair, feathers,

or skin); dust mite and cockroach parts, fungi (molds); infectious

agents (bacteria or viruses); and pollen.

Everyone is exposed to biological pollutants. The effects on one’s

health, however, depend upon the type and amount of biological

pollution and the individual person. Some people do not experience

health reactions from certain biological pollutants, while others may

experience one or more of the following reactions: allergic,

infectious, or toxic.

Except for the spread of infections indoors, allergic reactions may be

the most common health problem with indoor air quality in homes.

They are often connected with animal dander (mostly from cats and

dogs), with house dust mites (microscopic animals living in

household dust), and with pollen. Allergic reactions can range from

mildly uncomfortable to life-threatening, as in a severe asthma attack.

Health experts are especially concerned about people with asthma,

who have very sensitive airways that can react to various irritants,

making breathing difficult. Infectious diseases caused by bacteria and

viruses, such as flu, measles, chicken pox, and tuberculosis, may be

spread indoors. Most infectious diseases pass from person to person

through physical contact. Crowded conditions with poor air

circulation can promote this spread. Some bacteria and viruses 

thrive in buildings and circulate through indoor ventilation systems.

(For additional information on indoor air pollution, see Chapter 1,

Cleaner Air.)

As with air pollutants and radiation, biomonitoring methods are not

available or feasible for many of the biological pollutants discussed

in this section. 

What is the level of exposure to

disinfection by-products?

Disinfection by-products (DBPs) are chemicals that form in drinking

water when disinfectants are added during the drinking water

treatment process. Disinfectants are added to drinking water to kill

bacteria and other microbes that cause disease. DBPs are formed

when the disinfectants react with organic matter (primarily from leaf

and vegetation decay) that is found naturally in drinking water

sources such as rivers and lakes (EPA, 2002c). The most common

drinking water disinfectant is chlorine. Other lesser-used

disinfectants include chloramines, chlorine dioxide, ozone, and

ultraviolet light. More than 200 million people within the U.S. drink

disinfected water (EPA, June 2001a).

Hundreds of different DBPs—most of which result from chlorine—

have been identified in drinking water, and occurrence data have

been reasonably established for over 30 DBPs (EPA, ORD, November

1997). The two types of DBPs that are typically measured by

drinking water utilities are trihalomethanes (THMs) and haloacetic

acids (HAs). 

DBP levels vary throughout the country because the levels are

dependent on several factors, including amount of organic matter in

the drinking water source, amount of rainfall in the area, season of

the year, water temperature, type of disinfectant used, water

treatment plant configuration, and size of the water system

distribution system (EPA, 1999). 

Current information on DBP exposures draws on monitoring results

from drinking water systems. Data for average national levels of

THMs in treated drinking water are available. Water monitoring for

DBPs is of limited value in classifying or identifying individual

exposures to DBPs. Individual exposures are influenced by route of

exposure (ingestion, inhalation, dermal absorption), individual habits

relating to water use or consumption, time and spatial distribution of

DBPs in the water system, and seasonal variables that affect the

precursors to DBPs (e.g., rainfall, temperature). The complex nature

of exposure to DBPs will require a better understanding of the chain

of events as illustrated in Exhibit 4-1.

4.4.10 Endocrine Disruptors—An Emerging Issue

An endocrine disruptor is defined as an exogenous agent that alters

the function of the endocrine system and consequently causes

adverse health effects in an intact organism, or its progeny or

(sub)populations (IPCS, 2002). A number of pharmaceuticals,

pesticides, commercial chemicals and environmental contaminants

are known to disrupt the endocrine system across a wide range of

species—invertebrates, fish, birds, reptiles, and mammals. 
4-60 4.5 Assessing the Environmental Burden of Disease Chapter 4 - Human Health

There is little information on the magnitude and pattern of human

exposures to endocrine disruptors. The limited exposure data that

exist are primarily for various environmental media, such as chemical

concentrations in air, food, and water. Often these data are limited by

geographical regions and cannot be extrapolated to national trends.

More relevant measures of human exposure, such as chemical concentrations in human blood, breast milk, and human tissue, are rare.

Often these data are available only for high exposure areas and populations. As chemicals suspected of contributing to endocrine disruption in humans are identified, it will be necessary to obtain highquality exposure data to perform human risk assessments. Each

major state of the science report on endocrine disruptors has

acknowledged the critical need for research to increase our understanding of human exposures and related health outcomes.

The human health issue regarding exposure to endocrine disruptors

primarily relates to: (1) adverse effects observed in fish and wildlife,

(2) the increased incidence of specific endocrine-related adverse

human health outcomes/diseases, and (3) observations of endocrine

disruption in well-conducted experiments involving laboratory 

animals. These chemicals can affect the endocrine system in several

ways including interfering with hormone synthesis and release from

the endocrine gland, competing with the hormone for the binding

sites on transport proteins in the blood, binding to the receptor to

either block hormone action or mimic it, and producing changes in

hormone metabolism and elimination (IPCS, 2002). 

There are a few clear examples of adverse human health effects following high exposures to environmental chemicals (e.g., accidental

releases or poisoning incidents). Analysis of the human data by itself

has not provided firm evidence of direct causal associations between

low level exposure to endocrine-disrupting chemicals and adverse

human health outcomes. 

Of particular interest is exposure during very early development,

both in utero and postnatally. Sexual differentiation, growth, and

development are under hormonal control. Many of these early

processes are unique to this time period and disruptions of 

carefully timed processes may lead to irreversible adverse human

health outcomes. Interest has focused on: (1) adverse effects on

reproductive and sexual development and function, (2) altered

immune system, nervous system, and thyroid development and function, and (3) cancers of various endocrine-sensitive tissues including

the testes, breast, and prostate. Additional research is needed to

determine whether linkages exist between these adverse human

health outcomes/diseases and exposure to suspected endocrine 

disruptors. However, this research is challenging as the manifestation

of the condition is frequently not observed until years after exposure

has occurred and the measured concentration of the chemicals in

the affected adult may be very different from in utero, neonatal, or

pre-pubertal exposures/concentrations that may have given rise to

the adverse outcome.

4.5 Assessing the

Environmental Burden 

of Disease

Many factors may cause or influence disease in humans. These 

factors include heredity, social factors, dietary factors, and environmental factors (e.g., chemical pollutants, infectious microorganisms,

and radiation). The extent to which environmental factors influence

overall disease is not entirely understood. Disease burden, global

burden of disease, and environmental burden of disease are concepts

used to express the burden of disease on society:

■ Disease burden is the effect on society of both disease-related

mortality and disease-related morbidity (Kay, 2000; WHO, 2002).

It is assessed by several health measures, including mortality rates,

morbidity rates, and the number of days in the hospital.

Historically, disease burden has been investigated by analyzing

disease outcomes, such as cancer, rather than analyzing risk 

factors that may cause cancer or disease in general. For example, it

is easier to compare cancer incidence between two countries than

to compare risk factors of cancer; ionizing radiation may be the

major risk factor for cancer in country A, while dioxin may be the

major risk factor in country B. 

■ Global burden of disease (GBD) assesses the disease burden on

a worldwide basis and then apportions that burden to various

causes, such as genetic, behavioral, and environmental.

■ Environmental burden of disease (EBD) measures that portion

of the GBD which is due solely to environmental risk factors.

EBD provides a method for summarizing the environmental health of

populations. The summary health data collected from EBD measurements help identify environmental risk factors with significant public

health implications. EBD data can also be used to help prioritize

funding allocations for health and environmental research, assist in

environmental policy development, justify environmental advocacy,

assess the cost-effectiveness of interventions, and monitor the

progress of a population’s health (Prüss, et al., 2001). More important, EBD provides a way to normalize risk factors, allowing comparable health evaluations between populations. Two approaches are

commonly used to determine the degree of disease burden that

stems from environmental risk factors:

■ The outcome-based approach determines the degree to which

specific environmental risk factors cause a disease relative to other

environmental risk factors.

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Chapter 4 - Human Health 4.5 Assessing the Environmental Burden of Disease 4-61

■ The exposure-based approach assesses the adverse health outcomes resulting from dose-response relationships between risk

factors and associated disease outcomes (Prüss, et al., 2001).

This section summarizes estimates, in different studies, of the 

environmental burden of disease. 

World Health Organization Evaluation

In 1998, WHO estimated that 23 percent of GBD is due to environmental hazards, including occupational exposures (WRI, et al., 1998).

In 1999, WHO researchers and researchers from the University of

California reported that an estimated 25 to 30 percent of the GBD

was attributable to the environment (Smith, et al., 1999). 

In 2000, WHO introduced a new methodology for evaluating

changes to EBD, termed comparative risk assessment (CRA). CRA

measures the GBD due to risk factors. WHO is currently developing

CRA guidelines to help countries and smaller population groups,

such as villages and towns, measure their respective EBD (Kay,

2000). CRA does not have one standard unit, however, and it 

incorporates other methodologies used to assess EBD. Because of

this variability in assessment methodologies, comparing EBD for 

different countries can be difficult. Further, because EBD has not

been quantified extensively in the U.S., this country’s level of EBD

cannot be easily compared with that of the rest of the world.

Doll and Peto Estimates

Richard Doll and Richard Peto quantified the environmental contribution to disease in their 1981 landmark study The Causes of Cancer:

Quantitative Estimates of Avoidable Risks of Cancer in the United States

Today. In that study, they concluded that pollutants in air, water, and

food contributed from 2 to 5 percent to cancer mortality (Doll and

Peto, 1981). They quantified the portion of cancer deaths that were

attributable to various environmental causes, excluding tobacco

smoke (Exhibit 4-40). Thirty percent of cancer was ascribed to

tobacco use. 

Other Estimates

Other studies of EBD have investigated specific environmental risk

factors and disease outcomes. For example, Wynder and Gori 

concluded in 1972 that environmental factors caused 12 percent of

all cancer cases for men and 14 percent for women in the U.S. 

(Doll and Peto, 1981).

Why EBD Estimates Differ

EBD estimates are affected by the definition of “environment” that is

used in making the determination (Smith, et al., 1999), as well as the

measurement unit used, such as reporting mortality as a percentage

of the population. For example, some researchers include factors

such as stress or injury as environmental causes of disease, while

others include stress and injury as social causes of disease. 

The quantity of disease burden (such as disease outcome or risk

factors) measured in EBD studies also produces variation in EBD

estimates. These differences can be attributed to the different ways

that risk factors are categorized, or to differences in the amount of

disease burden attributed to a particular source.

Exhibit 4-40: Estimated proportions of cancer deaths 

in the United States attributed to selected 

environmental factors

Occupation Pollution Industrial 

Products

Environmental sources

Percentage of cancer deaths

Geophysical 

Factors

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Note: Tobacco is not included in this table. There was not a distinction between 

environmental tobacco smoke and mainstream smoke. 

Source: Doll, Richard and Richard Peto. The Causes of Cancer: Quanitative Estimates 

of Avoidable Risks of Cancer in the United States Today. 1981.
4-62 4.6 Challenges and Data Gaps Chapter 4 - Human Health

4.6 Challenges and 

Data Gaps

This chapter described key indicators for health and exposure. 

Many exposure indicators presented were measured by biomonitoring. Where biomonitoring data are not available, ambient exposure

measures serve to describe human exposure to key environmental

pollutants. Areas where strong associations have been demonstrated

between environmental exposures and health outcomes were 

highlighted. However, in many areas those associations have not yet

been demonstrated. 

The success of environmental decisions in improving public health

can be measured on a variety of levels:

■ National level (e.g., U.S. Department of Health and Human

Services’ Healthy People 2010 initiative).

■ Geographic/regional level (e.g., East Coast versus West Coast,

CDC’s state health reports).

■ Community level (e.g., air and water quality monitoring).

■ Individual level (e.g., screening programs for blood lead in 

children). 

Many indicators may be used at a number or all of these levels. 

This report has focused on describing indicators and impacts at a

national level. Future versions of this report may utilize indicators to

evaluate success in reducing environmental health exposure and 

outcomes at some of the other levels as well.

Use of Health Outcome Measures to Evaluate

Environmental Policy Decisions or Interventions 

Mortality data were chosen as one of the major disease indicators

because these are collected nationwide in every state, county, and

community. These mortality data constitute a comprehensive database, since every death is presumed to be reported. This information

has been collected for more than the past 50 years and has been

used to document the success of major public health programs. For

example, treatment of drinking water through filtration or chlorination eliminated diarrhea diseases as a major cause of death in the

20th century. More recently, anti-smoking campaigns aimed at men

are believed to be responsible for the sudden downward trend in

deaths due to lung cancer. In fact, an analysis of the key indicators of

health for the country confirm that the health of the U.S. population

is improving. The U.S. population is living longer (life expectancy)

and death rates for major causes of death (cancer, cardiovascular

disease) are declining. Except for those rare diseases that have a

short survival period and 100 percent death rate, death represents

only a small fraction of the true number of cases for a disease in the

population (see Section 4.2).

Better information and insight into the health of the U.S. population

can be obtained from evaluating incidence data (new cases of illness)

or prevalence data (all existing cases of illness). At this time, no comprehensive nationwide systems for collecting incidence or prevalence

data on disease are in place. The majority of morbidity data reported

in this chapter are available either from national surveys that sample

the U.S. and are assumed to be representative of the nation, or from

data (e.g., birth defects and cancer registries) collected by the statebased centers around the country. The actual picture of health may

differ from that suggested by the data, as in the case of childhood

asthma prevalence that has been rising (as described in Section

4.3.4). CDC has launched an initiative to improve the nation’s health

tracking system. CDC recently awarded grants to state and local

health departments to begin developing a national environmental

health tracking network and to develop capacity in monitoring environmental health at the state and local levels (<http://www.cdc.gov/

nceh/tracking/EPHTracking/EPHTracking.htm>).

Several emerging areas of health concern (e.g., Parkinson’s disease,

diabetes) and emerging areas of environmental exposure (e.g.,

endocrine disrupters) were recognized in this chapter. In many of

these areas, either the link between environmental exposures and

the disease has not been established or no systematic surveillance

or established indicators currently exist. Future reports may well

include many of the diseases and exposures identified as emerging

issues and may establish associated indicators. Major efforts to

address diabetes, asthma, and obesity also present a very 

promising opportunity to incorporate research on the role of 

environmental exposures into such plans.

Use of Exposure Measures to Evaluate Environmental Policy

Decisions or Interventions 

Most exposure indicators described in this chapter were biomonitoring indicators. Ambient exposure measures were described for a 

number of areas where, at present, biomonitoring data are not 

available (e.g., for certain air pollutants where there are no markers 

in blood or urine). 

The NHANES data provide examples where biomonitoring data have

reflected a public health benefit from EPA actions. For example, the

decline in blood lead levels confirms that the removal of lead from

gasoline, water, and paint has successfully reduced exposures.

Similarly, the decline in urinary cotinine levels demonstrates that

efforts to reduce smoking have led to public health improvements.

However, interpretation of many of the other exposure indicators is

difficult at this time. Either not enough is known about the exposure

levels in the population, or data gathering at a national level has just

begun. It will take time for a stable reference base to emerge. 

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Technical Document ■ EPA’s Draft Report on the Environment 2003

Chapter 4 - Human Health 4.6 Challenges and Data Gaps 4-63

Efforts to establish a national reference base are under way through

the work of CDC’s National Center for Environmental Health, which

is developing the National Human Exposure to Environmental

Chemicals Report. The first report was released in 2001

(<http://www.cdc.gov/nceh/dls/report/PDF/CompleteReport.pdf>)

and a second one was released in January 2003 with data on 116

chemicals (<http://www.cdc.gov/humanexposure>). CDC is

committed to expanding this database, and its recent Federal Register

notice called for nominations of chemicals to consider for inclusion

in the third report, to be published in 2005. The report will fill a

critical need to describe exposure. Use of the report indicators for

explanatory or predictive functions will require an understanding of

pathways and sources that may have contributed to the exposure

and the exposure’s relationships to health effects. With this

additional understanding the report ultimately could be used to

guide exposure reduction programs. 

Monitoring Environmental Health Status at the

Community Level

Except for mortality data, many communities must look to their 

own local public health officials to monitor the health status of their

community. This is true for a number of reasons, including:

■ Current health surveys have limited application at the community

level and often require extrapolation from a larger population

(state or national). 

■ Current disease reporting systems, whether national sample or

reporting systems (e.g., National Notifiable Diseases Reporting

System), can rarely provide an answer for a specific community.

■ Biomonitoring surveys that apply to specific communities are

extremely rare. For example, blood lead screening programs, while

common across the country, do not report in a systematic fashion

to a centralized location for compilation and analysis of the data. 

Until such systems are developed, communities will continue to rely

on environmental monitoring programs to tell them about their

exposure to air or water pollution. EPA is pursuing a number of

activities to increase the capacity of information providers (e.g.,

states) and users (e.g., communities) to share information. This

effort includes working closely with other federal agencies, such as

CDC, to build compatible systems for linking health and

environmental data bases. One potential outcome of such

partnerships is an opportunity to revisit and refine current sampling

designs such that future data collection efforts would provide better

information for smaller units (community level) and would ensure

better temporal and spatial congruence between environmental,

biomonitoring, and surveillance programs. 

Future Challenges 

For EPA to make better use of more direct indicators of public health

outcomes, the science underlying the Agency’s key public health

functions (describe, explain, predict, evaluate) will need to be

strengthened. EPA will continue to work on providing a better understanding of the components of the source-dose-health continuum

(Exhibit 4-1). Key among them will be establishing the necessary

degree of predictive validity between indicators of each component

(e.g., exposure versus dose). Such an understanding is critical to

defining the degree to which one indicator can be successfully used

as a surrogate for another. However, this may not be conducive to

widespread use in surveys or may be difficult to ascertain in smaller

populations (e.g., at a community level). 

EPA also will continue to build collaborations with CDC and other

federal agencies responsible for collecting health surveillance and

human exposure data. Such partnerships are essential to any effort

to describe the status and trends of exposure and disease in the U.S.

with the eventual goal of every U.S. citizen understanding what the

status is for his or her family and community. An important initiative

along these lines is the interagency effort to develop the National

Children’s Study, in which EPA is a collaborator. The Children’s Health

Act of 2000 authorized the National Institutes of Child Health and

Disease and a consortium of federal agencies “to conduct a national

longitudinal study of environmental influences on children’s health

and development.” The study will investigate the interaction of 

biologic, genetic, social, and environmental factors to better 

understand their role(s) in children’s health. 

EPA will also seek to develop and evaluate methodologies for

understanding the contribution of other risk factors to a given

health condition in comparison to the environmental exposure

(i.e., partitioning out the risk attributable to the environmental

exposure[s] of concern). Such measures will assist in prioritizing

intervention/prevention programs and will allow the benefits and

cost of environmental management to be placed in the context of

the larger public health picture. 

Other issues of emerging, or emerged, concern include:

■ Susceptible populations. This chapter identified children as a

susceptible population and described indicators relating specifically to them. EPA also recently announced an initiative to define the

environmental risks associated with the ever-increasing aging population (<http://www.epa.gov/epahome/headline_103002.htm>)

to be undertaken in partnership with other federal agencies and

the many alliances for the aging. Many of the indicators in this

report are particularly relevant to the elderly (e.g., cardiovascular

disease, chronic obstructive pulmonary disease), and they are, or

can be, reported by age group. As other susceptible populations

are identified, EPA will need to continue working with its federal

partners to see that the data are collected and analyzed to track

those populations.
4-64 4.6 Challenges and Data Gaps Chapter 4 - Human Health

■ Aggregate and cumulative risks. Individuals are not exposed to

single chemicals, but rather to multiple pollutants and other

stressors through multiple pathways and routes over the course of

a day. The reality of aggregate and cumulative exposures further

complicates attempts to attribute risk to a single environmental

agent. EPA has begun to look at this issue, stimulated in part by

mandates under the Food Quality Protection Act. The recently

released Cumulative Risk Guidance report (EPA, 2003e) lays the

groundwork for taking on this challenge and will help target the

research to better understand the nature and impact of such

“composite” exposures, especially as related to targeting

regulatory and health prevention strategies.

Finally, the health and exposure indicators described in this chapter

are only a portion of the story on the state of the environment.

These indicators should be viewed in conjunction with the other

indicators identified in the companion chapters on ecological

condition, land, air, and water. As presented in Exhibit 4-1, that

integration is vital to fully developing the understanding envisioned

by the cascade of events from source to effects.

EPA’s Draft Report on the Environment 2003 ■ Technical Document
Chapter 5:

Ecological Condition
Indicators selected and included in this chapter were assigned to one of two categories:

Q Category 1 - The indicator has been peer reviewed and is supported by national level data coverage for more than one time

period. The supporting data are comparable across the nation and are characterized by sound collection methodologies, data

management systems, and quality assurance procedures.

Q Category 2 - The indicator has been peer reviewed, but the supporting data are available only for part of the nation (e.g., multistate regions or ecoregions), or the indicator has not been measured for more than one time period, or not all the parameters of

the indicator have been measured (e.g., data has been collected for birds, but not for plants or insects). The supporting data are

comparable across the areas covered, and are characterized by sound collection methodologies, data management systems, and

quality assurance procedures. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.0 Introduction 5-3

5.0 Introduction

As described in Chapter 4, Human Health, EPA is moving in the

direction of measuring outcomes that reflect the actual impacts that

result from environmental pollution. This chapter applies that

approach to ecosystems. Previous chapters examined impacts on air,

water, and land—all elements of the environment that EPA seeks to

protect. This chapter links the state of the nation’s air, water, land,

and living organisms into a broad framework termed “ecological

condition”—the sum total of the physical, chemical, and biological

characteristics of the environment, and of the resulting processes

and interactions among them.1 Understanding ecological condition is

crucial, because humans depend on ecosystems for food, fiber, flood

control, and countless other critical “services” they provide to

society (Daily, 1997). Many Americans also attribute deep

significance and important intangible benefits to ecosystems and

their diverse flora and fauna.

Ecological condition reflects the result of a complex array of factors,

including natural disturbances, invasions of new species, resource

management, planning and zoning, and pollution. EPA has statutory

authority to regulate only a few of these factors, but it exerts policy

leadership across a broad spectrum of public and private activities,

including review of significant federal projects under the National

Environmental Policy Act (NEPA). These efforts reflect the EPA’s

important role as one of many federal, tribal, state, and local government and private partners in protecting the nation’s environment. 

This chapter asks questions about our current understanding of the

ecological condition of:

Q Forests

Q Farmlands 

Q Grasslands and shrublands

Q Urban and suburban areas

Q Fresh waters 

Q Coasts and oceans

Q The entire nation2

Exhibit 5-1 is a depiction of the events that link environmental

changes to ecological outcomes. “Stressors,” indicated by arrows, represent factors such as insect outbreaks or pollutants affecting the

system. These act directly on one or more of the “essential ecological

attributes” shown in the circles in the center of the diagram. (These

attributes are described in more detail below.) Each of these attributes

can, in turn, act on and be acted on by others. The web of arrows

among the indicators illustrates some of the possible interactions.

Effects on ecological attributes can be direct or indirect. This diagram

illustrates the fact that ecological processes have important feedbacks

on the chemical and physical structure of the environment in which

these changes occur. The overall changes in the attributes result in

altered structure and function of the ecosystem, which in turn lead to

outcomes (good or bad) about which society is concerned.

Exhibit 5-1 shows that monitoring only stressors or monitoring

single ecosystem attributes–such as living things–in isolation 

cannot convey a full and accurate picture of ecological condition.

Assessments of ecological condition must incorporate measures of

different characteristics, potentially at different times and in different places within a system. EPA can build on decades of monitoring

stressors to develop and appropriately monitor multidimensional

and better-linked ecological condition indicators. 

This chapter presents initial work toward identifying indicators that

can help to answer the question “What is the ecological condition

of the U.S.?” and it can help elucidate the sequence of events

shown in Exhibit 5-1. The chapter is organized into nine sections

that describe:

Q The framework used in this report to identify indicators to assess

ecological condition and outcomes (Section 5.1).

Q The ecological condition of forests (Section 5.2), farmlands

(Section 5.3), grasslands and shrublands (Section 5.4), urban and

suburban areas (Section 5.5), fresh waters (Section 5.6), coasts

and oceans (Section 5.7), and the entire nation (Section 5.8).

Q The key challenges and data gaps for developing adequate 

indicators of ecological condition (Section 5.9).

Because ecological condition depends critically on the physical and

chemical characteristics of land, air, and water, this chapter draws on

indicators from Chapters 1 through 3 of this report, as shown in

Exhibit 5-2. Those chapters should be consulted for the data

sources for those indicators. Many of the indicators were drawn from

The H. John Heinz III Center for Science, Economics, and the

Environment (The Heinz Center) report, The State of the Nation’s

Ecosystems: Measuring Lands, Waters, and Living Resources of the United

States, 2002, which also presents more detail on data sources, as

does Appendix B of this report.

The key data sources reflect the fact that monitoring ecological condition is a multi-organizational task. Organizations in addition to EPA

that are responsible for collecting the data to support indicators in

this chapter include:

Q The U.S. Department of Commerce (National Oceanic and

Atmospheric Administration)

Q National Aeronautics and Space Administration

Q The U.S. Department of Agriculture (Forest Service, Agricultural

Research Service, National Agricultural Statistics Service, and

Natural Resource Conservation Service)

Q The U.S. Department of Interior (U.S. Geological Survey and U.S.

Fish and Wildlife Service)

Q NatureServe, a private foundation

1The term ecosystem is used in its broadest sense as any interacting system of physical, chemical, and biological components and the associated

flows of energy, material, and information (Odum, 1971).

2This seventh category refers to the overall condition of the complex,

interconnected mosaic of different ecosystem types across the 

entire nation.
Programs such as the U.S. Department of Agriculture Forest

Inventory and Analysis (FIA) program and the Natural Resources

Inventory (NRI) have a long history, because they measure aspects

of the environment that are critical to multi-billion dollar industries

(e.g., timber, crops, etc.). Programs with a strictly “ecological” focus

(e.g., the USDA Forest Service Forest Health Monitoring [FHM]

Program, the U.S. Geological Survey National Water Quality

Assessment Program [NAWQA], the multi-agency Multi-Resolution

Land Characterization Consortium [MRLC], and EPA’s Environmental

Monitoring and Assessment Program [EMAP]) are newer on the

scene, and most have produced only Category 2 indicators as this

report goes to press.

Like Chapter 4, Human Health, this chapter is not intended to be

exhaustive. Rather, it provides a snapshot, at the national level, of

current U.S. ecological condition indicators and status based on key

data sources with sufficiently robust design, quality assurance, and

maturity. 

EPA’s Draft Report on the Environment 2003 Q Technical Document

5-4 5.0 Introduction Chapter 5 - Ecological Condition

Altered 

Structure/ 

Function

Outcomes

Landscape 

Condition

Chemical/ 

Physical 

Characteristics

Ecological 

Processes

Hydrology/ 

Geomorphology

Biotic 

Condition

Natural 

Disturbance 

Regimes

Exhibit 5-1: Ecological condition paradigm

Together, the six ecological attributes constitute "ecological condition."

Stressors (shown as ) affect ecological attributes directly and also indirectly through feedback 

(interaction)among the attributes ( ) Stressors Stressors

Stressors

Stressors

Stressors

Stressors
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.0 Introduction 5-5

Question Indicator Name Category Section

Question Indicator Name Category Section

Question Indicator Name Category Section

Exhibit 5-2: Ecological Condition - Questions and Indicators

Forests

Extent of forest area, ownership, and management 1 3.1.4

Nitrate in farmland, forested, and urban streams and ground water 2 2.2.4.b

Deposition: wet sulfate and wet nitrogen 2 1.2.2

Changing stream flows 1 2.2.4.a

Extent of area by forest type 1 5.2

Forest age class 2 5.2

Forest pattern and fragmentation 2 5.2

At-risk native forest species 2 5.2

Populations of representative forest species 2 5.2

Forest disturbance: fire, insects, and disease 1 5.2

Tree condition 2 5.2

Ozone injury to trees 2 5.2

Carbon storage 2 5.2

Soil compaction 2 5.2

Soil erosion 2 5.2

Processes beyond the range of historic variation 2 5.2

Extent of agricultural land uses 1 3.1.2

The farmland landscape 1 3.1.2

Nitrate in farmland, forested, and urban streams and ground water 2 2.2.4.b

Phosphorus in farmland, forested and urban streams 2 2.2.4.b

Pesticides in farmland streams and ground water 2 2.2.4.c

Potential pesticide runoff from farm fields 2 3.2.4

Sediment runoff potential from croplands and pasturelands 2 3.1.6

Pesticide leaching potential 2 5.3

Soil quality index 2 5.3

Soil erosion 2 5.3

What is the ecological condition of forests?

What is the ecological condition of farmlands?

Farmlands

Extent of grasslands and shrublands 1 3.1.3

Number/duration of dry stream flow periods in grasslands and shrublands 2 2.2.4.a

At-risk native grassland and shrubland species 2 5.4

Population trends of invasive and native non-invasive bird species 1 5.4

Grasslands and Shrublands

What is the ecological condition of grasslands 

and shrublands?

Note: Italicized indicators are presented in other chapters.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-6 5.0 Introduction Chapter 5 - Ecological Condition

What is the ecological condition of coasts 

and oceans?

Question Indicator Name Category Section

Question Indicator Name Category Section

Question Indicator Name Category Section

Extent of urban and suburban lands 1 3.1.1

Ambient concentrations of ozone: 8-hour and 1-hour 2 1.1.1.b

Nitrate in farmland, forested and urban streams, and ground water 2 2.2.4.b

Phosphorus in farmland, forested, and urban streams 2 2.2.4.b

Chemical contamination in urban streams and ground water 2 2.2.4.c

Patches of forest, grassland, shrubland, and wetland in urban/suburban areas 2 5.5

Wetland extent and change 1 2.2.2

Altered fresh water ecosystems 2 2.2.1

Contaminants in fresh water fish 2 2.5.1

Phosphorus in large rivers 2 2.2.4.b

Lake Trophic State Index 2 2.2.1

Chemical contamination in streams and ground water 2 2.2.4.c

Acid sensitivity in lakes and streams 2 2.2.4.c

Changing stream flows 1 2.2.4.a

Sedimentation index 2 2.2.4.a

Extent of ponds, lakes, and reservoirs 1 5.6

At-risk native fresh water species 2 5.6

Non-native fresh water species 2 5.6

Animal deaths and deformities 2 5.6

At-risk fresh water plant communities 2 5.6

Fish Index of Biotic Integrity in streams 2 5.6

Macroinvertebrate Biotic Integrity Index for streams 2 5.6

Urban and Suburban Lands

What is the ecological condition of urban 

and suburban areas?

Fresh Waters

What is the ecological condition of fresh waters?

Chlorophyll concentrations 2 2.2.3

Water clarity in coastal waters 2 2.2.3

Total nitrogen in coastal waters 2 2.2.4.b

Total phosphorus in coastal waters 2 2.2.4.b

Dissolved oxygen in coastal waters 2 2.2.3

Total organic carbon in sediments 2 2.2.3

Sediment contamination of coastal waters 2 2.2.4.c

Sediment toxicity in estuaries 2 2.2.4.c

Extent of estuaries and coastline 1 5.7

Coastal living habitats 2 5.7

Shoreline types 2 5.7

Benthic Community Index 2 5.7

Fish diversity 2 5.7

Submerged aquatic vegetation 2 5.7

Fish abnormalities 2 5.7

Unusual marine mortalities 2 5.7

Coasts and Oceans

Note: Italicized indicators are presented in other chapters.
Technical Document Q EPA’s Draft Report on the Environment 2003

5.1 Links Between Stressors

and Ecological Outcome:

A Framework for Measuring

Ecological Condition

The primary reasons to monitor ecological condition are similar to

those for monitoring air, water, and land;

Q To establish baselines against which to assess the current and

future condition.

Q To provide a warning that action may be required.

Q To track the outcomes of policies and programs, and adapt them

as necessary.

Measuring ecological condition is not as straightforward as monitoring

water or air to determine whether temperatures or concentrations of

pollutants exceed a legal standard, however. Ecosystems are dynamic

assemblages of organisms that have more or less continuously adapted

to a variety of natural stresses over shorter (e.g., fire, windstorms) and

longer (climate variations) periods of time, taking on new and different

characteristics. This makes determination of the condition of a “natural” system difficult (Ehrenfeld, 1992). In addition, people have altered

natural ecosystems to increase their productivity of food, timber, fish,

and game, and to provide the infrastructure needed to support a modern society. How should the ecological condition of these altered

ecosystems be measured, and against what reference points? Several

recent reports by experts in the field have provided advice to guide

current and future efforts. 

The National Research Council (NRC) report, Ecological Indicators for

the Nation (NRC, 2000), provides an introduction to recent national

efforts to measure ecological condition and a thoughtful discussion

of the rationale for choosing indicators. EPA’s Science Advisory

Board (SAB) also proposed a Framework for Assessing and Reporting

on Ecological Condition (EPA, SAB, 2002). The framework identifies

six “essential ecological attributes” (EEAs) of ecosystems: 

Q Landscape condition

Q Biotic condition

Q Chemical and physical characteristics

Q Ecological processes

Q Hydrology and geomorphology

Q Natural disturbance regimes

The EEAs, along with reporting categories and examples of

associated indicators, are displayed in Exhibit 5-3. Neither report

identifies specific methodologies, network designs, or actual datasets

corresponding to the examples.

The H. John Heinz III Center for Science, Economics, and the

Environment (The Heinz Center) led a nationwide effort by

government, academia, and the private sector to develop a report

entitled The State of the Nation’s Ecosystems: Measuring Lands, Waters,

and Living Resources of the United States (The Heinz Center, 2002).

According to the introduction, the report “provides a prescription

for ‘taking the pulse’ of the lands and waters. It identifies what

should be measured, counted, and reported, so that decision-makers

and the public can understand the changes that are occurring in the

American landscape.” The Heinz Center report identified 103

specific indicators, of which 33 were judged by the authors to have

adequate data for national reporting. 

The Heinz Center report provides an important core of indicators for

this chapter. The Heinz Center report uses a somewhat different categorization of indicators than the Category 1 and 2 designations,

and indicators identified by The Heinz Center that have inadequate

data or need further development have not been included here. The

Heinz Center indicators in this chapter are organized around the SAB

framework, but given the similarities among the NRC, SAB, and Heinz

Center approaches, this choice does not affect the final result. This

chapter also includes, in addition to The Heinz Center national indicators, some Category 2 indicators from regional monitoring studies that

Chapter 5 - Ecological Condition 5.1 Links Between Stressors and Ecological Outcome 5-7

Question Indicator Name Category Section

Ecosystem extent 2 5.8

At-risk native species 2 5.8

Bird Community Index 2 5.8

Terrestrial Plant Growth Index 1 5.8

Movement of nitrogen 1 5.8

Chemical contamination 2 5.8

The Entire Nation

What is the ecological condition of the 

entire nation? 

Note: Italicized indicators are presented in other chapters.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-8 I5.1 Links Between Stressors and Ecological Outcome Chapter 3 - Ecology

show promise for implementation on a national scale. Regardless of

whether the indicators are Category 1 or 2, all indicators were drawn

directly from scientifically defensible studies published in peerreviewed reports and journals.

One of the most critical data quality objectives of monitoring for EPA

is representativeness, the degree to which monitoring data accurately

and precisely represent the variations of a characteristic over an entire

population (e.g., all streams or forests)3. Sampling design4 approaches

the problem of representativeness and the effects of sampling and

measurement error on environmental management policies and decisions. Sampling designs fall into two main categories, probability designs

and judgmental designs. Probability designs apply sampling theory, so

that any sampling unit (e.g., a stream of a stand of trees in a forest)

has a known probability of selection. This important attribute allows

the characteristics of the entire population of streams or forest stands

to be estimated with known uncertainty, ensures that the results are

reproducible within that uncertainty, and enables one to calculate the

probability of decision-error based on the uncertainty in the data.

Probability designs do not provide information on the precise conditions at any location where measurements are not made, or of the

populations during times when measurements are not made,5 or of

populations not included in the sampling design.

Judgmental designs rely on expert knowledge or judgment to select

sampling units. They can be easier and less expensive to implement

than probability sampling. Monitoring sites selected at random can be

difficult or even impossible to access, and some monitoring programs

require sites that are easy to access repeatedly, or remote sites from

which to search for faint signals such as climate change or long-range

transport of pollutants. The accuracy of the results of judgment

designs depends on the quality of the professional judgment, but in

the best of cases quantitative estimates of uncertainty cannot be

made. In this report, Category 1 indicators were required to be based

on indicators collected using probability designs or “wall-to-wall” 

coverage by remote sensing, unless a strong case could be made that

the data were representative of the population being sampled.

This chapter follows The Heinz Center (2002) in reporting on six major

ecosystem types.6 With a few exceptions, environmental and natural

resource monitoring programs currently are structured to track the 

condition of individual natural resources (e.g., trees, crops, soil, water, or

air) represented by the first six ecosystem types. Though some of this

Exhibit 5-3: Essential ecological attributes and reporting categories

Source: EPA, Science Advisory Board. A Framework for Assessing and Reporting on Ecological Condition. June 2002.

Landscape Condition

Q Extent of Ecological System/Habitat Types

Q Landscape Composition

Q Landscape Pattern and Structure

Biotic Condition

Q Ecosystems and Communities

- Community Extent

- Community Composition

- Trophic Structure

- Community Dynamics

- Physical Structure

Q Species and Populations

- Population Size

- Genetic Diversity

- Population Structure

- Population Dynamics

- Habitat Suitability

Q Organism Condition

- Physiological Status

- Symptoms of Disease or Trauma

Chemical and Physical Characteristics 

(Water, Air, Soil, and Sediment)

Q Nutrient Concentrations

- Nitrogen

- Phosphorous

- Other Nutrients

Q Trace Inorganic and Organic Chemicals

- Metals

- Other Trace Elements

- Organic Compounds

Q Other Chemical Parameters

- pH

- Dissolved Oxygen

- Salinity

- Organic Matter

- Other

Q Physical Parameters

Ecological Processes

Q Energy Flow

- Primary Production

- Net Ecosystem Production

- Growth Efficiency 

Q Material Flow

- Organic Carbon Cycling

- N and P Cycling

- Other Nutrient Cycling

Hydrology/Geomorphology

Q Surface and Ground Water Flows

- Pattern of Source Flows

- Hydrodynamics

- Pattern of Ground Water Flows

- Salinity Patterns

- Water Storage

Q Dynamic Structural Characteristics

- Channel/Shoreline Morphology, Complexity

- Extent/Distribution of Connected Floodplain

- Aquatic Physical Habitat Complexity

Q Sediment and Material Transport

- Sediment Supply/Movement

- Particle Size Distribution Patterns

- Other Material Flux

Natural Disturbance Regimes

Q Frequency

Q Intensity

Q Extent

Q Duration

3Like the U.S. Census, which strives to collect data on every person in

the U.S., an ecological census could attempt to collect data on every plant,

animal, stream, etc. This is generally impossible or cost-prohibitive, except for

data collected on land cover or other features of the environment that can be

measured by satellite.

4Olsen, et al., 1999, and Yoccoz, et al., 2001, provide useful discussions of sampling oriented toward ecological monitoring.

5For example, if estuaries are sampled only in the fall, the sample reveals

nothing about estuaries in the spring or winter.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-9

monitoring takes place on a national level, it still focuses on discrete

resources or ecosystem types. For this reason, most available indicators

can help answer questions about the condition of individual ecosystem

types, but cannot track the overall ecological condition of an area 

comprising different interconnected and interacting ecosystem types.

Therefore, this chapter includes a seventh category representing 

indicators potentially suitable for the entire nation. 

A few indicators are available to help provide a more holistic assessment of ecological condition at the national level. For example, large or

migratory organisms (e.g., bears or neotropical birds, respectively)

depend on many ecosystem types over large areas for their continued

survival. As another example, all of the terrestrial ecosystems types

may contribute nitrogen, carbon, or sediment to streams and rivers in

watersheds. Even the arrangement of ecosystems in the landscape and

the composition of patterns of land cover and land use have been

identified as critical components in the way ecosystems function

(Forman and Godron, 1986; Naiman and Turner, 2000; Winter, 2001;

EPA, SAB, 2002). Section 5.8 corresponds approximately to the core

national indicators in The Heinz Center report. 

Ideally, the indicators in this chapter would be presented in a way

that spoke to the success of our efforts to protect and restore the

ecological condition of the types of ecosystems considered in this

chapter. Trends in biotic condition and ecological functions and in

the physical, chemical, hydrological, landscape, and disturbance

regimes of each ecosystem would provide keys to stories involving

acid rain, or landscape fragmentation, or changing climate. The

resulting “stories” would establish baselines, provide warnings, and

track the effectiveness of management actions by EPA and its partners, as envisioned by the NRC (2000). Because so few reliable data

exist on trends for any indicators at the national level, however, such

a presentation is not yet possible. Instead, the chapter presents a

disturbingly fragmentary picture of what little is known reliably and

nationally based on Category 1 indicators. It also anticipates what

could reasonably be known if monitoring of Category 2 indicators

were to be expanded. 

Sections 5.2 through 5.8 below describe the ecological condition of

the seven ecosystem types. Each section begins with an introduction

that summarizes data on the indicators that appear in the previous

chapters of this report on air, water, and land. Indicators presented

for the first time then are described in detail. Each section ends with

a summary of what the available indicators, taken together, reveal

about the ecological condition of that ecosystem type.

6The concept of an ecosystem, while extremely useful and relevant, is a

somewhat vague classification for purposes of environmental monitoring. See

O’Neill, et al. (1986); Turner (1989); Suter (1993), pp. 275-308; and Knight

and Landres (1998) for highly relevant discussions.

5.2 What is the Ecological

Condition of Forests?

Forests, as defined by the U.S. Department of Agriculture (USDA)

Forest Service (FS), are any lands that are at least 10 percent covered by trees of any size and at least 1 acre in extent (Smith, et al.,

2001). Some forested ecosystems are rich sources of biodiversity

and recreational opportunities, while others are managed intensively for timber production. All are important for carbon storage,

hydrologic buffering, and fish and wildlife habitat. Forested ecosystems are under pressure in the U.S. from a number of non-native

insects and pathogens and from deviations from natural fire regimes

(The Heinz Center, 2002). They also are becoming increasingly

fragmented by urbanization and other human activities (Noss and

Cooperrider, 1994).

Under its statutory programs, EPA has particularly focused on the

effects of air pollution on forest ecosystems, including the effects

of acid rain on forests and forest streams. Such impacts might

affect not only the health and productivity of trees, but also 

biodiversity in forest ecosystems (Barker and Tingey, 1992). Under

the Clean Air Act, EPA must promulgate secondary standards for

criteria air pollutants that present unreasonable risks to plants,

animals, and visibility. EPA also has statutory authority to control

the effects of forest management practices on aquatic communities; safe use of herbicides and pesticides in forest systems; and

significant federal activities in forested ecosystems subject to EPA’s

review under NEPA.

Forests are possibly the best monitored of the six ecosystem types

in this report. The Forest Service has long monitored standing timber volume and production, as well as damage from fire and pests, in

its Forest Inventory and Analysis (FIA) program (Smith, et al., 2001).

This program relies on probability sampling to ensure that the

results are statistically representative, and there is complete longterm national coverage. This results in two Category 1 indicators

relating to forest extent and one to biotic condition. In the early

1990s, the Forest Service in collaboration with EPA’s Environmental

Monitoring and Assessment Program (EMAP) developed the Forest

Health Monitoring (FHM) program to monitor additional indicators

of the ecological condition of forests (see Stolte, et al., 2002), also

using a probability design. Over the course of the 1990s, forests in

a growing number of states were sampled in the FHM program, and

many of the FHM indicators were merged into the FIA program in

1999. Although data on these indicators are now being collected in

47 states, with all 50 expected to be covered by 2005, at the time

this report was being prepared, coverage was not yet sufficiently

complete for these to reach Category 1 status.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-10 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

Essential Ecological Attribute Indicators Category Source

Landscape Condition

Biotic Condition

Ecological Processes

Chemical & Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I 2

Exhibit 5-4: Forest Indicators

Extent of Ecological System/

Habitat Types

Landscape Composition

Landscape Pattern/Structure

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Wet nitrogen deposition

Trace Organic and Inorganic Chemicals

Extent of forest area, ownership, and management

Extent of area by forest type

Forest age class

Forest pattern and fragmentation

At-risk native forest species

Populations of representative forest species

Forest disturbance: fire, insects, and disease

Nitrate in farmlands, forested, and urban 

streams and ground water

Wet sulfate deposition

Tree condition

Ozone injury to trees

Carbon storage

Soil compaction

Changing streamflows

Soil erosion

Processes beyond the range of historic variation

USDA

USDA

USDA

USDA

NatureServe

NatureServe

USDA

USDA

USDA

USDA

Ecosystems and Communities

Surface and Ground Water Flows

Physical Parameters

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

DOI

EPA

USDA

DOI

USDA

USDA

Other Chemical Parameters

EPA

Many of the indicators monitored by the FIA and FHM (Smith, et al.,

2001) were included in the Heinz report (2002) and formed the

original core of this chapter. As this chapter was being completed,

however, the Forest Service published its Final Draft National Report

on Sustainable Forests–2003 (USDA, FS, 2002) under the Montreal

Process. Several of the indicators contained in this 2002 report (all

Category 2) were included in this chapter to demonstrate the kinds

of data that will be available nationwide for a range of the forest

EEAs as the FIA achieves data collection and analysis on a national

basis. Data for several of these indicators (e.g., air quality, atmospheric deposition, and the chemistry and biology of forest streams)

are contributed by national monitoring programs operated by other

government and private sector organizations.

The forest indicators used in this report are displayed in Exhibit 5-4,

grouped according to the EEAs. Some indicators relating to the EEAs
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-11

of forest landscape condition, the chemical and physical attributes of

forest streams, and the hydrology of forest watersheds are discussed

in the chapters on Cleaner Air, Purer Water, and Better Protected

Land, because they also relate to questions about those media. This

section briefly summarizes the data for these indicators as they

relate to the ecological condition of forests. This section then introduces additional indicators that relate to the EEAs of forest landscape condition, biotic condition, ecological processes, physical condition of forest soils, and natural disturbances in forests.

The following indicators presented in the previous chapters relate to

the ecological condition of forests:

Q The indicator Extent of Forest Area, Ownership, and Management

(Chapter 3, Better Protected Land), is important for assessing

trends in how forests are managed and protected. Forested

ecosystems cover some 749 million acres in the U.S., or about

one-third of the total land area. While approximately 25 percent

lower than the pre-settlement acreage in the 1600s, the total

acreage has held steady for the past century, although regional

and local patterns have changed (USDA, FS, April 2001). Since

the 1950s, forest land has increased by 10 million acres in the

Northeast and North Central states, and decreased by 11 million

acres in the Southeast (USDA, FS, April 2001). 

About 55 percent of all U.S. forests are in private ownership, with

83 percent of forests in the East being privately held (USDA, FS,

2002). About 9 percent of forest lands are managed by private

industry to produce timber. Although 503 million acres of forests

are classified as “timberland,” the rest receive less intensive management. Harvest on public lands declined nearly 50 percent from

1986 to 2 billion cubic feet per year in 2001, but increased on private land by 1 billion cubic feet per year, to 14 billion cubic feet

per year during the same period (USDA, FS, 2002). About 38 percent of harvesting is by clearcut, mostly in the South (USDA, FS,

2002). About 76 million acres of forests are “reserved” and managed as national parks or wilderness areas, an almost threefold

increase since 1953 (USDA, FS, 2002). Much of the protected forest in the West is in stands more than 100 years old.

Q The indicator Nitrate in Farmland, Forested, and Urban Streams and

Ground Water (Chapter 2, Purer Water) is important for tracking

the loss of nitrate from forested watersheds, which often indicates

the effects of acid rain or insect infestation. In 36 forested

streams monitored by the National Water Quality Assessment

(NAWQA) program, almost 50 percent had concentrations of

nitrate less than 0.1 parts per million; 75 percent had concentration of less than 0.5 ppm; and only one had a concentration of

more than 1.0 ppm. By comparison, of 107 agricultural watersheds, almost half of the streams had nitrate concentrations

greater than 2.0 ppm. 

Q According to the indicator Deposition–Wet Sulfate and Wet Nitrogen

(Chapter 1, Cleaner Air), wet sulfate deposition decreased substantially throughout the Midwest and Northeast between 1989-

1991 and 1999-2001 (Chapter 1, Cleaner Air). By 2001, wet sulfate deposition had decreased by more than 8 kilograms per

hectare per year (kg/ha/yr) from 30-40 kg/ha/yr in 1990 in

much of the Ohio River Valley and northeastern U.S. The greatest

reductions occurred in the mid-Appalachian region. Wet nitrate

deposition levels remained relatively unchanged in most areas during the same period and even increased up to 3 kg/ha in the

Plains, eastern North Carolina, and southern California. 

Using National Atmospheric Deposition Program data, a USDA

report on sustainable forests observed that annual wet sulfate

deposition decreased significantly between 1994 and 2000, especially in the North and South Resource Planning Act (RPA)

regions, where deposition was the highest. Nitrate deposition

rates were lowest in the Pacific and Rocky Mountain RPAs, where

approximately 84 percent of the regions experienced deposition

rates of less than 4.7 kg/ha/yr (4.2 pounds per acre per year).

Only 2 percent of the sites in the eastern U.S. received less than

that amount (USDA, FS, 2002).

Q The indicator Changing Stream Flows (Chapter 2, Purer Water)

addresses altered stream flow and timing, which are critical

aspects of hydrology in forest streams. Low flows define the smallest area available to stream biota during the year, and high flows

shape the stream channel and clear silt and debris from the

stream. Some fish depend on high flows for spawning, and the timing of the high and low flows also can influence many ecological

processes. Changes in flow can be caused by dams, water withdrawal, and changes in land use and climate. This indicator reveals

that 10 percent of predominantly forested watersheds showed

decreased minimum flow rates during the period 1940 through

2000 compared to the period before 1940, while 25 percent had

increased minimum flow rates (USDA, FS, 2002). Five percent of

the watersheds had lower maximum flow rates, and 25 percent had

higher maximum flow rates compared to the earlier period. There

were no obvious trends in maximum flow rates in the decades

since 1940, but minimum flow rates increased over the period.

Increased flows were generally found in the East, but decreased

flows were found in the West.

The other 12 forest indicators in Exhibit 5-4, described on the

following pages, appear for the first time in this report in this

chapter. Most of these indicators are from the Final Draft National

Report on Sustainable Forests-2003 (USDA, FS,2002) which

became available after The Heinz Center report went to press. All

are Category 2 indicators because the data are not yet available

for the entire country.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-12 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

Trends in the distribution of forest types ultimately control the

different types of communities that they support. The data for

this indicator were collected by the FIA program, which currently

updates the assessment data every 5 years. This indicator compares current conditions to those in 1977.

What the Data Show

Oak-hickory forest is the most common forest type in the U.S.,

covering 132 million acres—an increase of 18 percent since 1977

(Exhibit 5-5). Maple-beech-birch forest covers 55 million acres and

has increased 42 percent since 1977. Pine forest of various types

covers 115 million acres; spruce-birch forests cover 61 million acres

(mostly in Alaska); and Douglas fir covers 40 million acres, mostly

in the Pacific Northwest. Mixed forests (e.g., oak-pine and oakgum-cypress) cover 64 million acres, mostly in the South (USDA,

FS, 2002).

In the East, longleaf-slash pine and lowland hardwoods (elm-ashcottonwood and oak-gum-cypress) had the largest decreases in

acreage (12 million and 17 million acres, respectively). In the

West, hemlock-sitka spruce, ponderosa pine, and lodgepole pine

decreased the most (by 9 million, 8 million, and 6 million acres,

respectively). In both regions, “non-stocked” land, on which trees

have been cut but that has not yet regrown as forest, has declined

steadily.

Indicator Gaps and Limitations

Limitations of this indicator include the following:

Q Since the late 1940s, field data on species composition have

been collected on a probability sample of 450,000 sites,

nationwide (Smith, et al., 2001). The resulting estimates of area

by forest type have an uncertainty of 3 to 10 percent per 

million acres of area sampled (The Heinz Center, 2002).

Q The data do not include information on private lands that are

legally reserved from harvest, such as lands held by private

groups for conservation purposes. Other forest lands are at

times reserved from harvest because of administrative or other

restrictions. Data on these lands would provide a more complete picture of U.S. forest lands. 

Data Source

The data source for this indicator was Forest Resources of the

United States, 1997, Smith, et al., 2001. (See Appendix B, 

page B-36, for more information.)

Indicator Extent of area by forest type – Category 1

0

20

40

60

80

100

120

140

1950 1960 1970 1980 1990 2000

Million Acres

Other

Softwoods

Fir -Spruce

Juniper

Douglas Fir

Western Forest Cover Types Increasing in Area

0

20

40

60

80

100

120

140

1950 1960 1970 1980 1990 2000

Million Acres

Ponderosa Pine

Hemlock-Sitka

Spruce

Lodgepole Pine

Nonstocked

Western Forest Cover Types Decreasing in Area

0

20

40

60

80

100

120

140

1950 1960 1970 1980 1990 2000

Million Acres

Oak-Hickory

Maple-BeechBirch

LoblollyShortleaf Pine

Other Types

Eastern Forest Cover Types Increasing in Area

0

20

40

60

80

100

120

140

1950 1960 1970 1980 1990 2000

Million Acres

Lowland

Hardwoods

Northern

Conifers

Aspen-Birch

Longleaf-Slash

Pine

Nonstocked

Eastern Forest Cover Types Decreasing in Area

Exhibit 5-5: Forest types in the United States, 1963-1997

Coverage: All 50 states. 

Source: The Heinz Center. The State of the Nations Ecosystems. 2002. 

Data from the USDA, Forest Service.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-13

Maintaining forest cover with a wide age range and a variety of

successional stages sustains habitats for a variety of forestdependent species and provides for the sustainable yield of a

range of forest products. This indicator reports the percentage of

forest area, with stands in each of several age classes.7

What the Data Show

In the eastern U.S., 35 percent of forests classified as “timberlands” are more than 60 years old, and 10 percent are more than

100 years old; in the West, the corresponding numbers are

70 percent and 35 percent, respectively (Exhibit 5-6). Softwood

age distributions are skewed slightly toward younger age classes

due to their management for timber. Hardwoods have a more

normal distribution, with a peak in the 40 to 79 year age class,

reflecting maturing second and third growth forests in the East.

Stands averaging 0 to 5 inches and those over 11 inches are

increasing, while intermediate stands in the 6 to 10 inch range

are decreasing, indicating a rise in selective harvesting in the U.S.

(USDA, FS, 2002).

Indicator Gaps and Limitations

Data for national parks and wilderness areas and other forested

land are not available at this time, but will be in the future (The

Heinz Center, 2002).

Data Source

The data source for this indicator was Forest Resources of the

United States, 1997, Smith, et al., 2001. (See Appendix B, 

page B-36, for more information.)

Indicator Forest age class – Category 2

0

1997 Future

10

20

30

40

50

Percent of Forest Lands Percent of Forest Lands

0

1997 Future

10

20

30

40

50

Age of Stand (yrs)

1-19

20-59

60-99

100-199

200+

Age of Stand (yrs)

1-19

20-59

60-99

100-199

200+

Uneven-Aged

Coverage: all 50 states (timberlands only.) 

Note: "Timberlands" is a USDA Forest Service designation for lands 

that grow at least 20 cubic feet of wood per acre per year, which is 

considered be sufficient to support commercial harvest under current 

economic conditions. Lands on which harvest is prohibited by statute 

are not included as "timberlands." Note also that the term 

"uneven-age" is being phased out; such stands are composed of 

intermingled trees that differ considerably in age.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from the USDA, Forest Service. 

Partial Indicator Data: West (Timberlands Only)

Partial Indicator Data: East (Timberlands Only)

Data Not Adequate for Reporting on

Forest Lands Other Than Those Classified as Timberlands

Exhibit 5-6: Forest age class, 1997

7Age class is defined by the mean age of the dominant or codominant crowns in the upper layer of the tree canopy.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-14 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

Indicator

Forest pattern and fragmentation affect the plant and animal

species that live in forests. Large blocks of contiguous forest support interior forest species. Partial forest cover creates forest edge

habitat, which supports birds and other animals that nest in

forests but forage in nearby fields (Ritters, et al., 2002).

Fragmentation also creates areas that concentrate airborne nutrients and pollutants by increasing the amount of unprotected forest edge (Weathers, et al., 2001). This indicator captures some of

these features.

What the Data Show

Fragmentation in forests in the U.S. is significant. Based on 1992

data (The Heinz Center, 2002), two-thirds of all points within

forests were surrounded by land that was at least 90 percent 

forest in their “immediate neighborhood” (i.e., a radius of

250 feet) (Exhibit 5-7). However, only one-fourth of the points

within forests were surrounded by land that was at least 

90 percent forest within their “larger neighborhood” (i.e., to a

radius of 2.5 miles) (The Heinz Center, 2002). Approximately half

of the fragmentation consists of “holes” in otherwise continuous

forest cover. About three-quarters of all forest land is found in or

near the boundaries of these large (greater than 5,000 hectares),

but heavily fragmented, forest patches (Ritters, et al., 2002). In

short, most forest is near other forest, and “holes” in forest cover

caused by development, agriculture, harvesting, etc., tend to be

isolated from each other.

Indicator Gaps and Limitations

Although this indicator was calculated for the conterminous U.S.,

it has been categorized as a Category 2 indicator because it is

only one of many potentially important fragmentation indicators.

The exact impact of the amount and type of fragmentation on

biotic structure and ecological processes is poorly known, and is

likely to vary from one species and process to another (Ritters, et

al., 2002). The FHM program is developing additional landscape

fragmentation indicators, but the data have not been fully evaluated as this report was being finalized.

Data Sources

The data source for this indicator was Forest Health Monitoring

National Technical Report, 1991 to 1999, U.S. Department of

Agriculture, Forest Service, Southern Research Station, 2002; and

Fragmentation of Continental United States Forests, Ritters, et al.,

2002. (See Appendix B, page B-37, for more information.) 

Forest pattern and fragmentation – Category 2

0

10

20

30

40

50

60

70

80

Future

West

East

1992 1992 1992 Future Future

Immediate

Neighborhood

Local

Neighborhood

Larger

Neighborhood

percent of neighborhood that is mostly forest

Exhibit 5-7: Forest cover and neighborhood size, 1992

Immediate neighborhood: land within a radius of about 250 ft from each forest point.

Local neighborhood: land within a radius of about 1/4 mile from each forest point.

Larger neighborhood: land within a radius of about 2 1/2 miles from each forest point

Mostly forest: land that is at least 90% forested (less than 10% nonforest)

Coverage: lower 48 states

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the 

Multi-Resolution Characterization Consortium and the USDA, Forest Service.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-15

Species richness is considered to be an important indicator of

ecological condition by both the National Research Council

(2000) and the Science Advisory Board (2002). Although the

role of species richness in maintaining a stable ecosystem is

debated, greater species richness (i.e., greater number of species)

is generally accepted as desirable. Species richness could be

altered by air pollution, fragmentation, and forest disturbance by

fire, insects, or disease.

What the Data Show

Based on an assessment of 12 factors, NatureServe and its member programs in the Natural Heritage program determined that

5 percent of forest animal species are imperiled, 3.5 percent are

critically imperiled, and 1.5 percent are or might be extinct (The

Heinz Center, 2002) (Exhibit 5-8). This indicator includes reports

on mammals, amphibians, grasshoppers, and butterflies; too little is

known about other groups, including plants, to assign risk categories. NatureServe data reveal that of the 1,642 species of terrestrial animals associated with forests, 88 percent still occupy

their full historical geographic range on a state-by-state basis

(USDA, FS, 2002).

The Natural Heritage Program uses standard ranking criteria and

definitions, making the ranks comparable across groups. This

means that “imperiled” has the same basic meaning whether

applied to a salamander, a moss, or a forest community. Ranking is

a qualitative process, however, taking into

account several factors that function as guidelines rather than arithmetic rules. The ranker’s

overall knowledge of the element allows him 

or her to weigh each factor in relation to the

others and to consider all pertinent information for a particular element. The factors considered in ranking species include population

size, range extent and area of occupancy,

short- and long-term trends in the foregoing

factors, threats, and fragility (Stein, 2002).

The information gathered by Natural Heritage data centers also

provides support for official designations of endangered or threatened species. However, because Natural Heritage lists of vulnerable species and official lists of endangered or threatened species

have different criteria, evidence requirements, purposes, and taxonomic coverage, they normally do not coincide completely with

the official designations of “rare and endangered” species.

Indicator Gaps and Limitations 

The data for this indicator are not from a site-based monitoring

program, but rather from a census approach that focuses on the

location and distribution of at-risk species. Determining whether

species are naturally rare or have been depleted is currently not

possible. It is not clear that trends can be quantified with any

precision.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from the

NatureServe Explorer Database. (See Appendix B, page B-37, for

more information.)

Indicator At-risk native forest species – Category 2

0

5

10

15

20

25

2000 Future

Percent of all Forest Species Exhibit 5-8: At-risk native forest species, by risk category, 2000

Coverage: all 50 states.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from NatureServe

and its Natural Heritage member programs.

Partial Indicator Data: Animals Only

Extinct

Critically

Imperiled

Imperiled

Vulnerable

All Rare/At Risk

Data Not Adequate for National Reporting on Forest Plants
EPA’s Draft Report on the Environment 2003 Q Technical Document

Indicator

5-16 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

The abundance of species representative of particular forest types

is a more sensitive and less dramatic measure of ecological

condition than species richness alone. Species richness reflects

the net number of species invading an area and species going

extinct, whereas species abundance also includes the numbers of

individuals in each species (USDA, FS, 2002). The FHM program

has collected abundance data on bird and tree species.

What the Data Show

Between 1966 and 1979, 21 percent of bird species associated

with forests experienced population declines. This figure rose to

26 percent between 1980 and 2000 (USDA, FS, 2002). Areas

with the greatest population declines were along the coasts and in

the Appalachians. Between 1966 and 2000, 26 percent of bird

species associated with forests showed population increases.

In the majority of tree species groups, the number of trees with

trunk diameters greater than 1 foot increased by more than

50 percent between 1970 and 2002, indicating a more abundant

community of older trees (USDA, FS, 2002) (Exhibit 5-9).

Indicator Gaps and Limitations

Several limitations are associated with this indicator:

Q Population data are available only for birds and trees. Data for

big game are reported by the states, but generally very few

systematic measures of animal population density exist. 

Q The data from the Breeding Bird Survey (BBS) are based on a

volunteer observer program and might not be statistically

reliable.

Data Sources

The data sources for this indicator were the Breeding Bird 

Survey, U.S. Geologic Survey (1966-2000); and U.S.

Department of Agriculture, Forest Service. Draft Resource

Planning and Assessment Tables, 2002; and National Report on

Sustainable Forests-2003, Final Draft, U.S. Department of

Agriculture, Forest Service, 2002. (See Appendix B, page B-38,

for more information.)

Populations of representative species – Category 2

0

10

20

30

Number of tree species 

or groups of 

species

6 8 10 12 14 16 18 20 25 29+

< -50% -50 to 0% 0 to +50% > +50%

diameter class (inches)

Coverage: 37 states.

Source: USDA, Forest Service. Draft Resource Planning Act Assessment Tables. 

May 3, 2002 (updated August 12, 2002). (September 2002;

http://www.ncrs.fs.fed.us/4801/FIADB/rpa_tabler/Draft_RPA_2002_Forest_Resource_Tables.pdf.)

Exhibit 5-9: Populations of representative forest species, 1970-2002
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-17

Fires, insects, and disease often occur naturally in forests. Their

impact on forest ecosystems can be influenced by their interaction with other variables such as management decisions, air 

pollutants, and variations in climate. For example, trees weakened

by pollutants might be more susceptible to attack by pathogens.

When ecological processes are altered beyond a critical threshold, significant changes to forest conditions might result.

What the Data Show

Wildfire acreage has declined from a peak of more than 50 million

acres per year in the 1930s to 2 to 7 million acres per year, 

largely due to fire suppression policies (The Heinz Center,

2002).8 However, there has been a slight increase in fires in

national forests in recent decades, with 8.4 million acres burned

in 2000 (Exhibit 5-10). 

Insect damage fluctuates from year to year, mostly as a result of

population cycles of the gypsy moth and southern pine beetle,

affecting between 8 and 46 million acres per year. Data for two

major parasites, fusiform rust and mistletoe, are available only for

the past several years, but the total acreage affected is 43 to 44

million acres (The Heinz Center, 2002).

Indicator Gaps and Limitations

Limitations of this indicator include the following:

Q This indicator does not distinguish between forest fires, other

wildfires, and prescribed burns. It also does not track the

intensity of the fires. 

Q Data are not available on forests affected by diseases other

than those listed above.

Q Some insects can cause widespread damage before it is

apparent from aerial surveys.

Data Sources

The data sources for this indicator were The State 

of the Nation’s Ecosystems, The Heinz Center, 2002,

using data from Western National Forests: Nearby

communities are increasingly threatened by catastrophic

wildfires, U.S. General Accounting Office, 1999;

Forest Health Monitoring National Technical Report,

1991-1999, U.S. Department of Agriculture, Forest

Service, Southern Research Station, 2002; 

and National Fire Statistics, the National 

Interagency Fire Center, (See Appendix B, 

page B-38, for more information.)

Indicator Forest disturbance: fire, insects, and disease – Category 1

0

20

40

60

1975 1980 1985 1990 1995 2000 2005

Million of Acres 

Insects: gypsy moth, spruce budworm, southern pine beetle, mountain pine 

beetle, western spruce budworm (all but the gypsy moth are native to the 

United States.) 

Diseases: fusiform rust, dwarf mistletoe

Coverage: all 50 states

Note: Data are not limited to national forests.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the USDA, Forest Service Health Protection/Forest Health 

Monitoring Program (insects, disease) and the National Forest System (fire).

Insects

Fire

(including

grasslands/

shrublands)

Disease

Exhibit 5-10: Forest disturbance: fire, insects, and disease, 1979-2000

8These data include wildfires in grasslands and shrublands.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-18 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

Changes in tree condition reflect the sum total of factors acting

on the tree, including stress due to pollutants, climate, nutrient

status, soil condition, and disease. This indicator (called “diminished biological components” in USDA, FS, 2002), reports on the

percentage of trees in each region of the conterminous U.S. states

that exhibit significant changes in three measures: mortality volume, crown condition, and the area in fire Current Condition Class

3. A Resource Planning Act region (shown in Exhibit 5-11) was

considered to have poor tree condition (designated as diminished

biological components in the exhibit) if (1) average annual mortality volume was more than 60 percent of gross annual growth volume, or (2) the ZB-index, an indicator of crown condition, was

increasing at a rate of 0.015 or more per year, or (3) more than

half of the forest area was in fire Current Condition Class 3. Fire

condition Class 3 represents a major deviation from the ecological

conditions compatible with historic fire regimes and might require

management activities such as harvesting and replanting to

restore the historic fire regime. 

What the Data Show

According to the data for this indicator, 20 percent of forests in

the U.S. were observed to exhibit poor tree condition, 40.9 percent were in fair or good condition, and 38.8 percent had no or

insufficient data (USDA, FS, 2002) (Exhibit 5-11). Mortality was

highest in the Pacific Northwest and northern Minnesota, and a

large portion of these forests was in fire Current Condition Class

3, indicating that mortality might be producing a high fuel load.

The South and Rocky Mountain regions had the smallest areas of

poor tree condition, but more than half of those areas had insufficient data or no data at all.

Indicator Gaps and Limitations

The data used to calculate this indicator were available at the time

for only 32 states; more than half of the South and Rocky

Mountain regions had insufficient or no data at all.

Data Sources

The data sources for this indicator were Forest Health Monitoring

National Technical Report, 1991-1999, U.S. Department of

Agriculture, Forest Service, Southern Research Station, 2002, and

National Report on Sustainable Forests-2003, Final Draft, U.S.

Department of Agriculture, Forest Service, 2002. (See Appendix

B, page B-39, for more information.)

Indicator Tree condition – Category 2

Exhibit 5-11: Tree condition, 1990-1999

Coverage: 32 states.

Forest area having diminished biological components that may indicate changes in fundamental ecological processes and/or ecological continuity. 

Percentages based on forest area in conterminus 48 States. 

Source: Conkling, B., et al. Forest Health Monitoring National Technical Report 1991-1999. 2002.

RPA Region

North

South

Rocky Mtn.

Pacific Coast

U.S.

No or Yes No Insufficient Data

Diminished Biological Components?

percent 

29.8

56.9

52.3

0.0

38.8

37.1

43.1

29.2

59.5

40.9

33.1

0.0

18.5

40.5

20.3
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-19

Ozone injury to trees can be diagnosed by examination of plant

leaves (Skelly, et al., 1987; Bennet, et al., 1994). Foliar injury is the

first visible sign of injury of plants from ozone exposure and

indicates impairment of physiological processes in the leaves.

What the Data Show

Little or no ozone injury was reported at 97 percent of Pacific Coast

sites and 100 percent of Rocky Mountain sites (Exhibit 5-12). In

the North and South regions, however, 23 percent of biomonitoring

sites showed at least low levels of injury, with severe levels observed

at about 5 percent of the plots (USDA, FS, 2002).

Indicator Gaps and Limitations

Q Any further injury to the plant (beyond injury to the leaves)

requires that ozone penetrate through the stomata into the leaf

interior, which is regulated by a variety of environmental

processes; some plants that show foliar damage show no

further damage, and some plants show damage without

concurrent signs of leaf damage (EPA, ORD, July 1996). 

Q Biomonitoring site data were available for only 32 states at the

time the data for this indicator were analyzed.

Data Sources

The data sources for this indicator were the Forest Health

Monitoring Program, U.S. Department of Agriculture (1991-

2000) and National Report on Sustainable Forests-2003, Final

Draft, U.S. Department of Agriculture, Forest Service, 2002. 

(See Appendix B, page B-39, for more information.)

Indicator Ozone injury to trees – Category 2

Exhibit 5-12: Ozone injury to trees, 1994-2000

0

20

40

60

80

100

Percent of Plots

Biosite Index

little or no

injury

low 

injury

moderate

injury

severe

injury

North

Pacific Coast

Rocky Mt

South

Coverage: 32 states.

Source: USDA, Forest Service. National Report on Sustainable Forests - 

2003. Final Draft. 2002.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-20 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

As a result of photosynthesis, carbon is stored in forests 

for a period of time in a variety of forms before it is ultimately

returned to the atmosphere through the respiration and decomposition of plants and animals. A substantial pool of carbon is

stored in woody biomass (roots, trunks, and branches). Another

portion eventually ends up as dead organic matter in the upper

soil horizons. Carbon storage in forest biomass and forest soils 

is essential for stable forest ecosystems, and it reduces atmospheric concentrations of a carbon dioxide, a greenhouse gas 

(see Chapter 1, Cleaner Air). 

What the Data Show

For the period 1953 to 1996, the average annual net storage of

non-soil forest carbon pools was 175 million tonnes of carbon per

year (MtC/yr). The rate of storage for the last period of record

(1987-1996) declined to 135 MtC/yr (Exhibit 5-13). The

decrease in sequestration in the last period is thought to be due

to more accurate data, increased harvests relative to growth, and

better accounting of emissions from dead wood. The Northern

region is sequestering the greatest amount of carbon, followed by

the Rocky Mountain region. The trend of decreasing sequestration

in the South is due to the increase in harvesting relative to

growth. Some of the harvested carbon is sequestered in wood

products (USDA, FS, 2002). 

Indicator Gaps and Limitations

Limitations of this indicator include the following:

Q The data only cover forest classified as “timberland,” which

excludes about one-third of U.S. forests.

Q Carbon stored in soil is not included.

Q Several of the carbon pools are not measured, but are estimated

based on inventory-to-carbon relationships developed with

information from ecological studies.

Data Sources

The data sources for this indicator were the Forest Inventory and

Analysis, U.S. Department of Agriculture (1979-1995); and

National Report on Sustainable Forests, 2003, Final Draft, U.S.

Department of Agriculture, Forest Service, 2002. 

(See Appendix B, page B-39, for more information.)

Indicator Carbon storage - Category 2

North South Rocky Mtn Pacific Coast

Exhibit 5-13: Contribution of forest ecosystems to the total global carbon budget, 1953-1996

 Average annual net forest carbon change 

(Mt/yr), 1953-1996

250.0 

200.0 

150.0 

100.0 

50.0 

0.0 

 

Average million tons net carbon 

pool change per year (Mt/yr) 

Average net carbon million tons 

pool change per year (Mt/yr) 

Years of Period 

Abovegrd live 

Abovegrd 

standing dead 

Understory

Down dead 

Forest floor 

Blw grd live 

Blw grnd dead 1953-1962 

1963-1976

1977-1986

1987-1996

100

75

50

25

0 

-25

1987- 

1996

1977- 

1986 

1963- 

1976

1953- 

1962

 Year

Average annual net forest carbon change 

(Mt/yr) by region, 1953-1996

Coverage: lower 48 states.

Source: USDA, Forest Service. National Report on Sustainable Forests - 2003. Final Draft. 2002.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-21

This indicator measures the extent of changes to the physical

properties of forested soils resulting from forest harvesting, road

construction, or other human impacts that are of sufficient magnitude to lower soil fertility or cause significant reductions in site

productivity. Compaction can have a variety of negative effects on

soil fertility by causing changes in both physical and chemical

properties (Sutton, 1991; Fisher and Binkley, 2000). Reduction in

pore space makes the soil more dense and difficult to penetrate

and thus can constrain the size, reach, and extent of root systems.

Reduction in soil aeration and water movement can reduce the

ability of roots to absorb water, nutrients, and oxygen, resulting in

shallow rooting and stunted trees. Destruction of soil structure

can limit water infiltration and increase rates of runoff and soil loss

from erosion.

What the Data Show

Soil compaction is primarily a local phenomenon. More than 86

percent of the plots measured showed less than 5 percent of the

plot area exhibitng of soil compaction (Exhibit 5-14) (USDA, FS,

2003). Only a small fraction of plots (1.6 percent) showed compaction on more than 50 percent of the plot.

Indicator Gaps and Limitations

Soil physical properties (e.g., bulk density) are not conventionally

monitored in a way that facilitates national reporting, and the 

current approach relies heavily on visual inspection and the State

Soil Geographic Database (STATSGO) state soil maps (USDA, FS,

2003). No measurements were made of the degree or intensity of

compaction. Physical disturbances that are not readily visible from

the surface might be under-reported. Therefore the national maps

thus far are only indicative of the potential for soil compaction on

a regional basis. The FIA program has begun monitoring actual soil

physical properties at the FIA sites, to be used in conjunction with

the current method, but the data were not available nationally for

development of the indicator in 2002 (USDA, FS, 2003).

Data Source

The data sources for this indicator were the Forest Health

Monitoring Program, U.S. Department of Agriculture (1999-

2000); and State Soil Geographic Database (STATSGO) state soil

maps. (See Appendix B, page B-40, for more information.)

Indicator Soil compaction – Category 2

Coverage: 37 states.

Source: USDA, Forest Service. National Report on Sustainable Forests-2003. 2003.

Percent Compaction

Frequency

Cumulative percent

0

200

400

600

800

1000

1200

1400

1600

0 5 10 20 30 40 50 More

Frequency

0%

20%

40%

60%

80%

100%

Exhibit 5-14: Frequency distribution of percent of plot area 

exhibiting evidence of surface compaction reported on 

Forest Health Monitoring (FHM) Program plots, 1999-2000
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-22 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 

Erosion is a term used to describe various mechanisms that wear

away the land surface. Soil erosion is caused naturally by running

water, wind, ice, and other geologic processes, but forest harvesting and road construction can increase erosion beyond natural 

levels. Erosion in excess of soil formation decreases the long-term

productivity of forest systems and contributes to siltation of

streams, lakes, and reservoirs. The Water Erosion Prediction Project

(WEPP) model is commonly used in conjunction with the STATSGO

state soil maps to estimate and predict the amount of soil loss

based on several factors influencing erosion (Liu, et al., 1997).

What the Data Show

Modeled erosion rates on undisturbed forest lands were less than

0.05 ton per acre per year, on nearly 90 percent of the measured

plots, compared to 3.1 tons per acre per year in agricultural

ecosystems (USDA, FS, 2003) (Exhibit 5-15). Exposed mineral

soil is a substantial contributor to erosion in the regions of the

country sampled, and about 65 percent of the measured 

forest plots showed bare soil on less than five percent of the plot.

Indicator Gaps and Limitations

Limitations of this indicator include the following:

Q The modeling approach (WEPP) was originally designed for

agricultural systems. It might overestimate erosion from wellmanaged forest plots and underestimate erosion on plots 

that have been harvested and mechanically prepared (USDA,

FS, 2003). 

Q The erosion indicator was calculated for only 37 states by 2002.

Data Sources

The data sources for this indicator were the Forest Health

Monitoring Program, U.S. Department of Agriculture (1991-

2000); and State Soil Geographic Database (STATSGO) state soil

maps. (See Appendix B, page B-40, for more information.)

Indicator Soil erosion – Category 2

0

50

100

150

200

250

300

350

400

450

500

0.0 0.05 0.50 1.0 5.0 10.0 M

2-yr

100-yr

Number of Plots

-1

0

50

100

150

200

250

300

350

400

450

500

0.0 0.05 0.50 1.0 5.0 10.0 More

Modeled Erosion Rate (tons acre )

Coverage: 23 states, excluding Alaska and Hawaii

Note: As an initial step in this analysis, model runs assume an undisturbed forest.

Source: USDA, Forest Service. National Report on Sustainable Forests-2003. 2003.

Exhibit 5-15: Frequency distribution for modeled erosion rates on Forest Health 

Monitoring (FHM) Program plots (1999-2000) 

 following a 2-year (average) and 100-year storm event
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.2 What is the Ecological Condition of Forests? 5-23

The Forest Health Monitoring (FHM) program (USDA, FS, 2002)

provided one of the few examples of an indicator that considers the

essential ecological attribute of natural disturbance. The FHM program analyzed Forest Inventory and Analysis (FIA) data on climatic

events, fire frequency, and insect and disease outbreaks between

1996 and 2000. These data were compared to anecdotal data from

1800 to 1850 to determine whether recent patterns in such incidents were beyond the range of historic variation. The FIA data were

also compared to data from between 1978 and 1995 to determine if

they were beyond the range of “recent” variation.

What the Data Show

A number of incidents were determined to be outside the range of

recent variation in natural disturbance: 

Q El Niño during 1997 to 2000.

Q A 1998 ice storm in the Northeast. 

Q Total area burned in the West during 1996, 1998, and 2000,

and the total area burned nationwide in 2000.

Q Outbreaks of spruce beetle in 1996, spruce budworm in 1997,

and southern pine beetle in 2000.

Indicator Gaps and Limitations

Several limitations are associated with this indicator:

Q This analysis was limited by the lack of metric data 

(actual measurements) available to describe conditions from

1800 to 1850. 

Q A relatively complete data set for major forest insects and

diseases exists for the period 1979 to 2000, but these data are

too recent for establishing a historical baseline.

Data Sources

The data sources for this indicator were the Forest Inventory and

Analysis, U.S. Department of Agriculture (1979-1995); and

National Report on Sustainable Forests-2003-Final Draft, 

U.S. Department of Agriculture, Forest Service, 2002. 

(See Appendix B, page B-41, for more information.)

Indicator Processes beyond the range of historic variation – Category 2
EPA’s Draft Report on the Environment 2003 Q Technical Document

Summary: The Ecological Condition of Forests

The available data are not, at this point, sufficient to track the

progress of EPA’s programs as they relate to the ecological condition

of forest ecosystems. When the FHM/FIA program indicators are

measured nationwide and repeatedly, they will form an important

baseline against which to monitor the response of forests and their

associated fauna to air pollutants, climate change, and management

practices that impact forest ecosystems. At this point, the results of

the leaf injury indicator suggest that research and assessment of the

actual effects of ozone on forest ecosystems should be continued.

The increasing acreage of older forests stands and changes in forest

stream hydrology might bear watching inasmuch as these factors

alter responses of forest systems to air and water pollutants. 

Landscape condition

The total acreage of forests has remained steady over the past 

century and, although the acreage of some of the types of forests

have changed, none are currently at risk of being lost. Over the past

50 years, the amount of non-stocked forest has decreased, while the

amount of forest with older trees has increased. Forests are highly

fragmented, but most forest land exists in or near the boundaries of

large tracts of forest land. 

Biotic condition

Most forest-related species continue to occupy a large portion of

their original range. Eleven percent of species dependent on forest

land are imperiled (5.7 percent are mammals, 2.3 percent are

amphibians, and 1.4 percent are birds). Twenty-five percent of forest

bird species have declined since 1975 (mostly in the Southeast),

25 percent have increased (mostly in the North), and 50 percent

have stayed approximately the same. These results indicate that

some forest habitats may not be supporting all the species they did

historically. Currently no reliable data exist on the condition of biota

in forest streams nationally or regionally. Our understanding of the

relationship between indicators and biological conservation strategies remains weak (Lindenmeyer, et al., 2000). 

According to available data, 20 percent of forests monitored in the

U.S. were observed to exhibit poor tree condition, and 23 percent of

biomonitoring plots in the eastern U.S. showed more than a small

amount of ozone impact on plant leaves. Severe ozone damage to

leaves was observed at 5 percent of the plots. 

Ecological Processes

Annual rates of carbon storage in timberland increased over the

three decades between 1953 and 1986 due to increasing age of timber stands and growth of woodlots on what was once farmland.

However, annual storage declined in the decade 1987 to 1996, in

part because of harvesting in Southeastern forests.

Chemical and physical characteristics

Nitrate loss from most forests does not appear to be resulting in

high nitrate concentrations in forest streams, but few streams are

monitored in areas where nitrate deposition is high (the East), and

the baseline is too short to determine whether there are trends in

the data.

Hydrology and geomorphology

With respect to forest streams, there has been a tendency toward

decreased minimum flow rates in 10 percent of forest streams during

the period 1940 through 2000 compared to pre-1940, while 

25 percent of forest streams had increased minimum flow rates. 

Five percent of the watersheds had lower maximum flow rates and 

25 percent had higher maximum flow rates. There were no obvious

trends in maximum flow rates in the decades since 1940, but there

was an increase in the minimum flow rates during that period.

Increased flows were generally found in the East, and decreased flows

were found in the West. Soil compaction is a problem on more than

10 percent of the plots in only 10 percent of monitored forest land. 

Natural disturbance regimes

A number of events were determined to be outside the range of

recent variation in natural disturbance, including two El Niño

events, a severe ice storm in the Northeast, total area burned in

the West during three years and the total area burned nationwide

in 2000, and several tree pest outbreaks. The ecological consequences of these events are undoubtedly significant, but have not

been systematically analyzed.

Many indicators currently being evaluated by the FIA and FHM 

programs are not included in this section because the results were

not included in the Forest Service’s most recent report on sustainable forests (USDA, FS, 2002). Because most of these measurements are made in a way that allows unbiased estimates and known

uncertainty bounds, the ecological condition of forests will be even

better known in the coming years.

5-24 5.2 What is the Ecological Condition of Forests? Chapter 5 - Ecological Condition 
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.3 What Is the Ecological Condition of Farmlands? 5-25

5.3 What Is the Ecological

Condition of Farmlands?

Agricultural practices using high-yielding crop varieties, fertilization,

irrigation, and pesticides have contributed substantially to increased

food production over the past 50 years (Matson, et al., 1997).

These same practices also have altered the biotic interactions in

farmlands, with local, regional, and global ecological consequences

(Matson, et al., 1997). This report (following The Heinz Center,

2002) defines a farmland as consisting of not only of the lands used

to grow crops, but also the field borders, windbreaks, small woodlots,

grassland and shrubland areas, wetlands, farmsteads, small villages,

and other built-up areas within or adjacent to croplands. These land

covers/uses both support agricultural production and provide habitat for a variety of wildlife species. Farmlands include lands that grow

perennial and annual crops as well as lands that are used to produce

forage for livestock. This definition overlaps with other ecosystems;

most notably, pastures are considered croplands, but are also considered part of grassland/shrubland ecosystems.

Among ecologists concerned with ecological condition, farmlands

are often referred to as “agroecosystems.” EPA is interested not only

in the ecological condition of farmlands, but also in their effects on

adjacent ecosystems. Developing and implementing agricultural practices that integrate crop and livestock production with ecologically

Essential Ecological Attribute

Landscape Condition

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I 2

Indicators Category Source

Exhibit 5-16: Farmland indicators

Extent of Ecological System/Habitat Types

Landscape Composition

Landscape Structure/Pattern

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Other Chemical Parameters

Trace Organics and Inorganics

Extent of agricultural land uses

The farmland landscape

Nitrate in farmland, forested, and urban streams and ground water

Phosphorus in farmlands, forested and urban streams

Pesticides in farmland streams and ground water

Potential pesticide runoff from farm fields

Pesticide leaching potential

Soil quality index

Soil erosion

Sediment runoff potential from croplands and pasturelands

Ecosystems and Communities

Surface and Ground Water Flows

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

USDA

USDA

DOI

DOI

DOI

EPA

EPA

USDA

USDA

DOI

Physical Parameters
EPA’s Draft Report on the Environment 2003 n Technical Document

5-26 5.3 What Is the Ecological Condition of Farmlands? Chapter 5 - Ecological Condition

based management practices has become the key for sustainable

agriculture (NRC, 1999). 

Some of the data on farmlands are available through the National

Agricultural Statistics Service (NASS). Over the past 80 years, NASS

has administered the USDA’s program of collecting and publishing

national and state agricultural statistics. NASS currently publishes

more than 400 reports a year covering virtually every facet of U.S.

agriculture—production and supplies of food and fiber, prices paid

and received by farmers, farm labor and wages, and farm aspects of

the industry. These estimates are based on a statistical area sampling

frame that represents the entire land mass of the U.S. The biological

indicators currently measured by NASS are primarily related to crop

or animal production. However, NASS does not report on indicators

of ecological condition. Physical or chemical indicators usually provide information relevant for agronomic production, but also can

provide limited information on potential stressors to adjacent terrestrial and aquatic ecosystems such as soil erosion; nitrogen, phosphorus and pesticide runoff; and phosphorus and nitrate concentrations

in farmland streams.

In 1990, EPA and the USDA Agricultural Research Service (ARS)

undertook an interagency effort to assess the ecological condition of

agroecosystems as part of the Environmental Monitoring and

Assessment Program (EMAP). In 1994 and 1995, EMAP piloted a

regional-scale assessment in the mid-Atlantic region (Hellkamp, et

al., 2000). Some of the resulting indicators used in that pilot are

included as Category 2 indicators in this report. These indicators

could be measured in other regions and eventually across the nation

in conjunction with the NASS annual surveys.

The farmland indicators used in this report are displayed in

Exhibit 5-16, grouped according to the essential ecological attributes (EEAs). Some indicators relating to the EEAs of farmland

landscape condition, the chemical and physical attributes of farmland streams, and the hydrology of farmland watersheds have

been presented in the previous chapters on Better Protected Land

and Purer Water, because these indicators also relate to questions

about those media. Below, this section briefly summarizes the

data for these indicators as they relate to the ecological condition

of farmlands. The section then introduces additional indicators

that relate to the EEAs of physical and chemical properties of

farmland soils and the hydrology and geomorphology contribut -

ing to loss of soil from farmlands. Data are insufficient for national reporting on indicators in three of the six categories of EEAs:

biotic condition, ecological processes, and natural disturbance

regimes (The Heinz Center, 2002).

The following indicators presented in previous chapters relate to the

ecological condition of farmlands:

n According to the indicator Extent of Agricultural Land Uses 

(Chapter 3, Better Protected Land), croplands total 377 million

acres. As of 1997, Conservation Reserve Program (CRP) lands

totaled 32 million acres, excluding Alaska (USDA, NRCS, 2000).

Between 1982 and 1997, cropland decreased 10.4 percent, from

about 421 million acres to nearly 377 million acres. Of this

44-million acre decrease, however, 32.7 million acres are now

enrolled in the CRP, leaving an 11.3 million acre loss as a result of

conversion of croplands to other land uses (USDA, NRCS, 2000). 

Unfortunately, there is no single, definitive, accurate estimate of

the extent of cropland. Cropland is a flexible resource that is

constantly being taken in and out of production. In addition,

estimates of the amount of land devoted to farming differ because

different programs use different methods to acquire, define, and

analyze their data. For example, The Heinz Center report assesses

total cropland (including pasture and hayland) as covering

between 430 and 500 million acres in 1997, or about a quarter of

the total land area in the U.S. (excluding Alaska). This report does

not reconcile these differences, but does acknowledge that there

are different estimates. 

n The Farmland Landscape indicator (Chapter 3, Better Protected

Land) describes the degree to which croplands dominate the

landscape and the extent to which other land uses are

intermingled (The Heinz Center, 2002). Croplands comprise

about half of the larger farmland ecosystems in the East and

Southeast and almost three-quarters of the farmland ecosystems

in the Midwest (The Heinz Center, 2002). The remainder of the

farmland ecosystems are forests in the East, wetlands in the

Southeast, and both forests and wetlands in the Midwest. In the

West, about 60 percent of farmland ecosystems are cropland, with

grasslands and shrublands dominating the remainder in the

western and northern Plains areas. Forests and

grasslands/shrublands are about equal in the farmland landscape

for the non-cropland area of the South Central region. In many

areas of the U.S., other land cover types are almost as prevalent as

croplands and can provide habitat for non-agronomic species.

n The indicator Nitrate in Farmland, Forested, and Urban Streams and

Ground Water (Chapter 2, Purer Water) shows the loss of nitrate

from agricultural watersheds, usually indicating the extent to which

nitrogen fertilizer is lost or animal manure reaches streams via runoff

or ground water. Sampling in areas where agriculture is the primary

land use found that about 50 percent of the 52 stream sites

sampled and 45 percent of the ground water wells sampled had

nitrate concentrations greater than 2 ppm. About 20 percent of the

ground water sites and 10 percent of the stream sites sampled had

nitrate concentrations exceeding the drinking water nitrate standard

of 10 ppm. These figures are much higher than the nitrate

concentrations in forest streams (The Heinz Center, 2002).

n The indicator Phosphorus in Farmland, Forested, and Urban Streams

(Chapter 2, Purer Water), shows the loss of phosphorus from

agricultural watersheds, again usually indicating losses from

fertilizer and animal manures. Total phosphorus concentrations in

farmland streams were reported in four classes in the Heinz report:

< 0.1 ppm, 0.1-0.3 ppm, 0.3-0.5 ppm, and > 0.5 ppm (The Heinz

Center, 2002). EPA has set new regional criteria for phosphorous
Technical Document n EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.3 What Is the Ecological Condition of Farmlands? 5-27

concentration, ranging from 0.023 to 0.076 ppm, to protect

streams in agricultural ecosystems from eutrophication. The

criteria vary according to differences in ecoregions, soil types,

climate, and land use. The Heinz Center (2002) reports that

about 75 percent of farmland streams had phosphorous

concentrations greater than 0.1 ppm, thus exceeding any of EPA’s

criteria for eutrophication. Fifteen percent had phosphorous

concentrations equal to or exceeding 0.5 ppm (The Heinz Center,

2002). Average phosphorous concentrations in farmland streams

were similar to phosphorous concentrations measured in urban

streams. As with nitrate concentrations, forest streams had lower

phosphorous concentrations than farmland or urban streams.

n The indicator Pesticides in Farmland Streams and Ground Water

(Chapter 2, Purer Water), captures the extent to which chemical

conditions in streams may exceed the tolerance limits for aquatic

communities. All streams monitored by the National Water Quality

Assessment (NAWQA) program in farmland areas had at least one

pesticide at detectable levels throughout the year (The Heinz

Center, 2002). About 75 percent of these streams had an average

of five or more pesticides at detectable levels, and more than 80

percent of the streams had at least one pesticide whose

concentration exceeded the applicable aquatic life guideline.

About 60 percent of ground water wells sampled in agricultural

areas had at least one pesticide at detectable levels. A relatively

small number of these chemicals—specifically the herbicides

atrazine (and its breakdown product desethylatrazine),

metalachlor, cyanazine, and alachlor—accounted for most

detections.

n The Potential Pesticide Runoff from Farm Fields indicator (Chapter 3,

Better Protected Land) identifies the potential for movement of

agricultural pesticides by surface water runoff in watersheds

nationwide, based on factors known to be important determinants

of pesticide loss. These factors include: 1) soil characteristics, 

2) historical pesticide use, 3) chemical properties of the

pesticides used, 4) annual rainfall and its relationship to runoff,

and 5) major field crops grown. The indicator uses 1992 as a

baseline. Watersheds with high scores (i.e., the 4th quartile of

runoff estimates) have a greater risk of pesticide contamination of

surface water than do those with low scores (i.e., the 1st quartile

of runoff estimates). The highest potential for pesticide runoff is

projected for the central U.S., primarily in the upper and lower

Mississippi River valley and the Ohio River valley. These areas are

part of the “breadbasket” of the U.S., where pesticide application

is highest. Many of the western watersheds have not been

assessed. 

n The hydrologic attribute indicator Sediment Runoff Potential from

Croplands and Pasturelands (Chapter 3, Better Protected Land),

captures the loss of valuable soil from the farmland, sediment

impacts to the physical habitat of farmland streams, and transport

of many pollutants to downstream lakes, reservoirs, and estuaries.

This indicator combines land cover, weather patterns, and soils

information in a process model that incorporates hydrologic

cycling, weather, sedimentation, crop growth, and agricultural

management to estimate the amount of sediment that could

potentially be delivered to rivers and streams in each watershed.

The highest potential for sediment runoff is concentrated in the

central U.S., predominately associated with the upper Mississippi

River valley and the Ohio River valley. Most of the western U.S.

region is characterized by low runoff potential.

The other three indicators in Exhibit 5-16, described on the following

pages, appear for the first time in this chapter.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-28 5.3 What Is the Ecological Condition of Farmlands? Chapter 5 - Ecological Condition

Indicator

Retention of pesticides in their target areas maximizes pesticide

efficiency and minimizes off-site contamination (Hellkamp, et al.,

2000). Pesticide leaching not only can contaminate surface and

ground water, but also can have both chronic and acute toxic

effects on non-target organisms, such as fish, birds, and other

wildlife. This leaching potential is affected by soil properties, rainfall and runoff, pesticide chemistry, and other factors. The indicator was used as part of the NASS survey approach, so it has the

potential for national application.

What the Data Show

During the 1994-1995 period, there were about 13.5 million

acres of cropland in the MId-Atlantic region (Hellkamp et al,

2000). Although a large proportion of these 13.5 million acres

had soils with properties conducive to pesticide leaching, the

authors estimate that 50 percent (6.75 million acres) of the 

cropland received no pesticide application. Also, pesticides with

moderately high to high leaching potentials were seldom applied

to croplands with highly to very highly leachable soils.

Consequently, only about 1 million acres (less than 10 percent of

the total cropland acreage) was at moderately high to high risk for

loss of pesticides from the on-farm target area (Hellkamp, et al.,

2000).

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q The pesticide leaching potential indicator has only been applied

in the mid-Atlantic region and has not been tested or applied in

other regions. It has the potential to be applied in other areas,

but it will have to be adjusted for regional differences. 

Q Data collection occurred only during 1994 and 1995.

Data Source

The data source for this indicator was the Mid-Atlantic Integrated

Assessment Program, U.S. Environmental Protection Agency

(1994-1995). (See Appendix B, page B-41, for more information.)

Pesticide leaching potential – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.3 What Is the Ecological Condition of Farmlands? 5-29

A Soil Quality Index (SQI) was developed and measured for

agroecosystems in the mid-Atlantic region in 1994 and 1995

(Hess, et al., 2000; Hellkamp, et al., 2000). The SQI includes

indicators of soil attributes, including physical (i.e., clay content,

cation exchange capacity, base saturation), chemical (i.e., pH,

sodium adsorption ratio, total nitrogen, total carbon, organic carbon/clay), and biological (i.e., microbial biomass). The SQI score

is an average of eight numerical ratings (McQuaid and Olson,

1998) (Hellkamp, et al., 2000). The high soil quality range

begins at SQI scores of 2.4, while the range of low SQI scores is

from 0.0 to 1.6. While the SQI is an indicator of the capacity of

the soil to support plant growth and is related primarily to agricultural productivity, it can also provide information on the

capacity of the site to support non-agronomic plants.

This indicator was used as part of the NASS survey approach, so

it has the potential for national application.

What the Data Show

SQI scores were obtained for the

five-state mid-Atlantic region in

1994 and 1995 (Hellkamp, et al.,

2000) (Exhibit 5-17). In 1994, the

mean SQI score was 2.23 (CI9 =

2.17 to 2.29); in 1995, the mean

SQI was 1.98 (CI = 1.73 to 2.23).

The difference in SQI scores

between 1994 and 1995 was due

to different index calculation procedures and sampling variability.

SQI scores were lower in tilled soils

compared with untilled soils, such

as hay fields, in both 1994 and

1995. Untilled sites had higher

microbial biomass values than conventional or reduced tillage sites in

both years 

Evaluation of the individual factors

related to the moderate SQI scores

indicated that cation exchange

capacity (1994), carbon (total

1994, organic 1995), and microbial

biomass (1995) had the lowest values (Hellkamp, et al., 2000).

Increasing the carbon content of soils might increase their capacity to support plant growth. Retaining or adding crop residues to

the soils could increase both the carbon content and substrate

for microbial activity. Crop residues can also reduce soil erosion

and associated transport of nutrients and pesticides off the field.

Nutrients and pesticides contribute to negative effects on aquatic

receiving systems.

Indicator Gaps and Limitations 

Data are available only for the mid-Atlantic region for 2 years.

The indicator has the potential to be applied in other areas, but

it will have to be adjusted for regional differences.

Data Source

The data source for this indicator was the Mid-Atlantic Integrated

Assessment Program, U.S. Environmental Protection Agency (1994-

1995). (See Appendix B, page B-41 for more information.)

Indicator Soil quality index – Category 2 Soil Quality Index (mean and 95% confidence interval)

Low Moderate High

3

2.5

2

1.5

1

All Untilled Reduce

Tillage

Conventional

Tillage

Threshold

Threshold

1994

1995

Tillage Type

Exhibit 5-17: Soil quality index for different tillage systems

 in the mid-Atlantic states, 1994 and 1995

Coverage: Mid-Atlantic states.

Source: Hellkamp et al. Assessment of the Condition of Agricultural Lands in Six Mid-Atlantic States. 2000. 

Dashed lines represent thresholds between low, moderate, and high ranges 

in soil quality for supporting plant growth.

9The confidence interval (CI) of the mean is a range of values (interval)

with a known probability (confidence, in this case 95 percent) of containing

the true population mean. The 1994 measured SQI scores are only a sample

of the entire population of SQI scores for the region. While the mean of the

measured SQI scores was 2.23, there is a 95 percent probability that the

mean for the entire population would be between 2.17 and 2.29.
EPA’s Draft Report on the Environment 2003 Q Technical Document

Indicator

5-30 5.3 What Is the Ecological Condition of Farmlands? Chapter 5 - Ecological Condition

Sediment resulting from soil erosion and transport is the greatest

pollutant in aquatic ecosystems, both by mass and volume (EPA,

OW, August 2002). Soil particles also can transport sorbed nutrients and pesticides and carry these into aquatic systems where

these constituents contribute to water quality problems.

Agricultural soil erosion decreases soil quality and can reduce soil

fertility, and soil movement can make normal cropping practices

difficult (The Heinz Center, 2002). Soil erosion and transport can

occur both by wind and by water.

Soil erosion estimates were calculated using the U.S. Geological

Survey hydrologic unit codes watersheds (8-digit HUCs), National

Resources Inventory soils data, the Universal Soil Loss Equation

(Renard, et al., 1997), and the Wind Erosion Equation (Bondy, et

al., 1980; Skidmore and Woodruff, 1968). Soil parameters were

obtained from the USDA Natural Resources Conservation Service

database.

What the Data Show

The acreage of U.S. farmland with the greatest

potential for wind erosion decreased by almost

33 percent to about 63 million acres from 1982

to 1997 (The Heinz Center, 2002) (Exhibit 

5-18). This acreage represents about 15 percent of the total cropland in the U.S. The

acreage with the greatest potential for water

erosion also decreased by about 33 percent to

89 million acres, which represents about 22

percent of U.S. cropland (The Heinz Center,

2002). Reductions in erosion can occur through

improved tilling or management practices, taking

marginal land out of production, participation in

the Conservation Reserve Program, or similar

activities. These reductions not only can 

contribute to increased soil quality, but also

improved water quality in adjacent and 

downstream aquatic ecosystems.

Indicator Gaps and Limitations

This indicator provides estimates for the initiation of soil movement, not sediment transport or delivery off farmlands, which

would require additional measurements and calculations. The distance the soil particles are moved might be considerable or minimal and cannot be determined from soil erosion estimates.

Data Sources

The data sources for this indicator were the National Resources

Inventory, U.S. Department of Agriculture (1982-1997); and the

State Soil Geographic Database (STATSGO), U.S. Department of

Agriculture (1982-1997). (See Appendix B, page B-42, for more

information.)

Soil erosion – Category 2

Each dot equals 

20,000 acres of 

cropland that is 

most prone to 

wind erosion. 

Coverage: lower 48 states. 

Note: data cover cropland and Conservation Reserve Program lands, but not pasture. 

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the 

USDA, Natural Resources Conservation Service.

Exhibit 5-18: Croplands most prone to erosion, 1997 

Croplands most prone to wind erosion, 1997 

Each dot equals 

20,000 acres of 

cropland that is 

most prone to 

water erosion. 

 Croplands most prone to water erosion, 1997
Technical Document Q EPA’s Draft Report on the Environment 2003

Summary: The Ecological Condition of Farmlands

Farmlands represent a significant portion of the landscape, but their

ecological condition nationally, or even for most regions, is unknown.

In a limited number of watersheds in which agricultural lands are the

predominant land use, data indicate that concentrations of nitrate,

phosphorus, and many contaminants are above levels of concern, but

these data are not available for a representative sample of streams

that could serve as a baseline for water quality management decisions for the entire U.S. No data for national indicators are available

for three of the six essential ecological attributes, and many of the

indicators for the other EEAs relate primarily to crop or livestock

production. Habitat alteration and constituent loading from farmlands represent some of the major stressors on other ecosystems

(see Chapter 2, Purer Water, and Chapter 3, Better Protected Land,

for discussion of specific stressors.)

Landscape condition

While there is no single, definitive, accurate estimate of the extent of

cropland, it has been estimated to have decreased by 10.4 percent

between 1982 and 1997, from about 421 million acres to nearly 

377 million acres. Of this 44-million acre decrease, 32.7 million

acres are now enrolled in the CRP, leaving an 11.3 million acre loss as

a result of conversion of croplands to other land uses. The Heinz

report assesses total cropland (including pasture and hayland) as

covering between 430 and 500 million acres in 1997, or about a

quarter of the total land area in the U.S. (excluding Alaska). In many

areas of the U.S., other land cover types within croplands are almost

as prevalent as croplands themselves and can provide habitat for

non-agronomic species. For example, croplands comprise only half of

the larger farmland ecosystems in the East and Southeast and about

three-quarters of the farmland ecosystems in the Midwest. This situation suggests that much of the farmland in the country supports

more biodiversity and associated ecological processes than if it were

more completely monoculture. Indicators for fragmentation of farmland landscapes by development and the shape of “natural” patches

in farmland landscapes would be helpful additional indicators of

landscape condition (The Heinz Center, 2002).

Chemical and physical characteristics

The physical and chemical characteristics of farmlands could provide

information to measure national progress in controlling and managing non-point source pollutant transport to receiving waters under

EPA’s clean water Government Performance and Results Act (GPRA)

goal. Unfortunately, many of the indicators for physical and chemical

characteristics are estimated based on land use, rather than on

measurements of water quality. The National Water Quality

Assessment (NAWQA) program provides consistent and comparable

information on nutrient and pesticide concentrations in streams in

agricultural areas. The data show that nitrate and phosphorus concentrations in farmland streams are generally higher than in urban

and suburban streams, and that more than 80 percent of the

streams sampled had at least one pesticide whose concentration

exceeded guidelines for protection of aquatic life. The sites sampled

do not represent a probability sample and are too few to ensure that

these data are representative of farmlands nationwide. Additional

stream monitoring networks are required to assess the physical and

chemical characteristics of streams in agricultural areas and the

effectiveness of agricultural management practices for protecting or

improving stream quality. A pesticide leaching potential indicator and a

soil quality index indicate that only 10 percent of the soils in the midAtlantic region were highly leachable with respect to pesticides, and

that soil quality was in the “moderate” range, but the indicator has

not been widely applied elsewhere. 

Hydrology and geomorphology

Sediment Runoff results in loss of valuable soil from the farmland, sediment impacts to the physical habitat of farmland streams, and transport of many pollutants to downstream lakes, reservoirs, and estuaries. The highest potential for sediment runoff is concentrated in

upper Mississippi River valley and the Ohio River valley. Most of the

western U.S. region is characterized by low runoff potential. Between

1982 and 1997, the acreage with the greatest potential for water

erosion decreased by about 33 percent to 89 million acres, which

represents about 22 percent of U.S. cropland. Wind can also erode

soil. The acreage of U.S. farmland with the greatest potential for

wind erosion decreased by almost 33 percent to about 63 million

acres from 1982 to 1997, about 15 percent of the total cropland in

the U.S. There were no indicators of hydrology available for either

surface or ground water associated with agricultural ecosystems.

Modification or elimination of wetlands and riparian areas contributes to hydrologic alteration of farmlands, as does agricultural

irrigation, primarily in the western states. This consumption affects

not only surface water through irrigation return flows, but also

ground water through depletion of aquifers. Both water quantity and

quality can be affected in farmlands. No national, representative

monitoring programs exist for either the quantity or quality of water

in farmlands. 

No Category 1 or 2 indicators were available for this report for biotic condition, ecological processes, or natural disturbance regimes. The

Heinz Center (2002) suggested that several indicators could be

promising: soil biological condition, status of animal species in farmland areas, native vegetation in areas dominated by cropland, and

stream habitat quality. An indicator of ant diversity and wildlife habitat also was developed and tested in the mid-Atlantic region by the

Mid-Atlantic Integrated Assessment Program (MAIA). Data are insufficient, however, to report on agroecosystems nationally for any of

these indicators (Hellkamp, et al., 2000; The Heinz Center, 2002). A

particular problem in farmlands is establishing appropriate reference

conditions for biological structure and ecosystem function measures

(The Heinz Center, 2002). Agricultural systems are highly managed

ecosystems, so no natural reference exists. It would be unrealistic to

expect fish and invertebrate communities in farmlands to be comparable to relatively undisturbed forest or grassland ecosystems.

Chapter 5 - Ecological Condition 5.3 What Is the Ecological Condition of Farmlands? 5-31
EPA’s Draft Report on the Environment 2003 Q Technical Document

5.4 What Is the

Ecological Condition of

Grasslands and Shrublands?

Grasslands and shrublands include lands in which the dominant vegetation is grasses or other non-woody vegetation, or where shrubs

and scattered trees are typical (The Heinz Center, 2002). This

ecosystem type includes chaparral, deserts, mountain shrublands,

range lands, Florida grasslands, and non-cultivated pastures.

Grasslands and shrublands also can be used for grazing, so some

land use summaries may include them in estimates of farmlands.

Grasslands and shrublands include lands revegetated naturally or

artificially to provide a non-crop plant cover that is managed like

native vegetation. The vast majority of grasslands and shrublands

occur in the western U.S. Collectively, these ecosystems constitute

over one-third of the area in the conterminous U.S.

Environmental issues associated with grassland and shrubland

ecosystems include introduction of non-native and invasive species,

desertification, ground water depletion, and overgrazing. Several federal agencies (e.g., Bureau of Land Management, Forest Service,

National Park Service) have responsibility for the majority of publicly

owned grasslands and shrublands.

Ecological indicators used in this report for grassland and shrubland

ecosystems are listed in Exhibit 5-19. The Heinz report serves as the

primary source of information for this ecological resource (The Heinz

Center, 2002). The following indicators presented in previous chapters relate to the ecological condition of grasslands and shrublands: 

Q The Extent of Grasslands and Shrublands indicator (Chapter 3,

Better Protected Land) reveals that grasslands and shrublands

occupy about 861 million acres or just over one-third of the land

area in the conterminous U.S. states. Alaska contains about 205

million acres of grasslands and shrublands.

Q Number/Duration of Dry Stream Flow Periods in Grasslands and

Shrublands (Chapter 2, Purer Water) is an important indicator of

the hydrology of grasslands and shrublands. This indicator shows

that the percentage of no-flow periods has decreased in all

grassland and shrubland regions of the West (The Heinz Center,

2002). The percentage of no-flow periods was similar in 1950 and

1960 and then decreased in the 1970s, 1980s, and 1990s. The

1980s was a relatively wet period and experienced some of the

smallest percentages of no-flow periods over the 50-year period

on record. The duration of zero-flow periods also decreased

during the period from the 1970s through the 1990s, compared

to the 1950s and 1960s (The Heinz Center, 2002).

The two biotic structure indicators in Exhibit 5-19, described on the

following pages, appear for the first time in this chapter: At-Risk

Native Species and Population Trends of Invasive and Native, Non-invasive Birds.

5-32 5.3 What Is the Ecological Condition of Farmlands? Chapter 5 - Ecological Condition
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.4 What Is the Ecological Condition of Grasslands and Shrublands? 5-33

Essential Ecological Attribute

Landscape Condition

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I 2

Indicators Category Source

Exhibit 5-19: Grasslands and shrublands indicators

Landscape Composition

Landscape Structure/Pattern

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Other Chemical Parameters

Trace Organics and Inorganics

Physical Parameters

Extent of grasslands and shrublands DOI

Ecosystems and Communities At-risk native grassland and shrubland species NatureServe

Surface and Ground Water Flows

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

Number/duration of dry stream flow periods in 

grasslands/shrublands

DOI

Population trends in invasive and native non-invasive bird species DOI

Extent of Ecological System/Habitat Types
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-34 5.4 What Is the Ecological Condition of Grasslands and Shrublands? Chapter 5 - Ecological Condition

Native species contribute substantially to the goods and services

provided by grasslands and shrublands. These species have

evolved in and adapted to the reange of environmental conditions

that has occurred in grassland and shrubland ecosystems over

thousands of years. While species extinction is a natural geologic

phenomenon, the extinction of species has increased over the

past 100 years (Vitousek, et al., 1997), and many ecologists

believe that ecosystem function and resilience is related to biodiversity (Naeem, et al., 1999), so that preserving biodiversity is

critical for sustainable ecosystems. Whether or not this is always

the case10 many people believe that more species is preferable to

fewer species.

What the Data Show

About 3.5 percent of native grassland and shrubland animal

species are critically imperiled, 6 percent are imperiled, and 

0.5 percent are or might be extinct (The Heinz Center, 2002)

(Exhibit 5-20). When vulnerable species (7 percent) are counted,

about 17 percent of grassland and shrubland animal species are

considered “at risk.” 

Indicator Gaps and Limitations 

The data for this indicator are not from a site-based monitoring program, but rather from a census approach that focuses on the location and distribution of at-risk species. Determining whether species

are naturally rare or have been depleted is currently not possible. It

is not clear that trends can be quantified with any precision.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from

NatureServe Explorer database. (See Appendix B, page B-42, for

more information.)

Indicator At-risk native grassland and shrubland species – Category 2

Partial Indicator Data: Grassland and Shrubland Animals

0

 5

10

15

20

25

2000 Future

Percent of all Grassland/

Shrubland Species

Coverage: all 50 states.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from NatureServe and its Natural Heritage member programs.

Exhibit 5-20: At-risk native grassland and shrubland 

species, by risk category, 2000

Extinct

Critically

Imperiled

Imperiled

Vulnerable

All At-Risk

Data Not Adequate for National Reporting on Grassland and Shrubland Plants

10An ongoing debate exists within the scientific community on the Downing. 1994; Grime, 1997; Hodgson, et al., 1998; Wardle, et al., 2000)
Technical Document Q EPA’s Draft Report on the Environment 2003

Bird species are mobile and can respond quickly to environmental

change (The Heinz Center, 2002). The Heinz report uses an indicator of population trends in invasive and non-invasive birds to

determine if invasive bird species are increasing more than other

bird populations (The Heinz Center, 2002). Invasive species are

defined as non-native species (species that are not native to

North America or that are now found outside their historic range)

that spread aggressively. Some invasive bird species increase when

the landscape becomes more fragmented or stress on the ecological system increases. The invasive species considered for grassland

and shrublands are believed to be indicative of agricultural conversion, landscape fragmentation due to suburban and rural development, and the spread of exotic vegetation (The Heinz Center,

2002). Native, non-invasive species are considered to reflect relatively intact, high-quality native grasslands and shrublands (The

Heinz Center, 2002). 

What the Data Show

Since the late 1960s, invasive and non-invasive bird species

increased in similar proportions until the period 1996 to 2000,

when invasive species increased significantly (The Heinz Center,

2002) (Exhibit 5-21). This increase might represent a short-term

fluctuation in bird populations, or it could be a sign of changing

ecosystem condition. Continued monitoring of bird populations

and indicators in other essential ecological attributes is required

to evaluate these changes. 

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q The calculation method could mask increases or decreases in

particular species. The two groups of birds contain species that

differ in their habitats, relative abundance, and range, and bird

populations normally fluctuate from year to year. If half the

species in one of the groups were to increase and the other half

to decrease over a given period, no consistent change would

appear for that group (The Heinz Center, 2002). 

Q The recent period of change is too short to provide an

indication of a possible increasing trend in invasive bird species. 

Data Source

The data source for this indicator was the Breeding Bird Survey,

U.S. Geological Service (1966-2000). (See Appendix B, 

page B-42, for more information.)

Indicator Population trends of invasive and native, non-invasive birds – Category 1

Chapter 5 - Ecological Condition 5.4 What Is the Ecological Condition of Grasslands and Shrublands? 5-35

0

20

40

60

80

100

1966-

1970

1971-

1975

1976-

1980

1981-

1985

1986-

1990

1991-

1995

1996-

2000

Percent of Species Increasing

Coverage: selected grassland and shrubland areas.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from the 

U.S. Geological Survey, Breeding Bird Survey; analysis by W. Mark Roberts. 

Exhibit 5-21: Population trends of invasive and 

native, non-invasive birds, 1966-2000

Native,

non-invasive

Invasive
EPA’s Draft Report on the Environment 2003 Q Technical Document

Summary: The Ecological Condition of Grasslands and

Shrublands

Grassland and shrubland ecosystems are at risk from the introduction of non-native and invasive species, desertification, ground water

depletion, and overgrazing. Few ecological indicators are currently

being measured at a national or regional scale, and this situation is

unlikely to change in the near future, so the overall ecological condition of the nation’s grasslands and shrublands is and will remain

effectively unknown.

Landscape condition

The extent of grasslands and shrublands can be estimated from

National Land Cover Database (NLCD) information. Grasslands 

and shrublands occupy about 861 million acres or just over onethird of the land area in the conterminous U.S. Alaska contains about

205 million acres of grasslands and shrublands. This is a diverse

group of ecosystems, however, ranging from Florida grasslands to the

Mohave desert, and land use information is not readily available for

all of them.

Biotic condition

At-risk native species and population trends in invasive and non-invasive birds are two indicators that can provide information on the status of, and change in, biotic condition. About 3.5 percent of native

grassland and shrubland animal species are critically imperiled, 

6 percent are imperiled, and 0.5 percent are or might be extinct.

When vulnerable species (7 percent) are counted, about 17 percent

of grassland and shrubland animal species are considered “at risk.”

However, there is no context in which to interpret the at-risk native

species data. The proportion of species that would naturally be rare

is unknown. Invasive species are believed to be indicative of agricultural conversion, landscape fragmentation due to suburban and rural

development, and the spread of exotic vegetation, whereas native,

non-invasive species are considered to reflect relatively intact, highquality native grasslands and shrublands. Until recently, invasive and

non-invasive bird species have changed in similar proportions, but

from 1996 to 2000, invasive species increased significantly. This

might be a short-term fluctuation in bird populations, or it could be

a sign of changing ecosystem condition. Information on stream biota

in grasslands and shrublands are needed to be able to assess the

condition of grassland and shrubland streams, especially as it may be

affected by grazing.

Hydrology and geomorphology

Periods of no flow can certainly be stressful to aquatic communities

of grasslands and shrublands, and may indicate harm to the vegetation during drought periods. The Number/Duration of Dry Stream Flow

Periods indicator has decreased in all grassland and shrubland regions

of the West. The percentage of no-flow periods was similar in 1950

and 1960 and then decreased in the 1970s, 1980s, and 1990s. The

duration of zero-flow periods also decreased during the period from

the 1970s through the 1990s, compared to the 1950s and 1960s.

Currently, dry stream flow periods are not monitored nationally.

There were no Category 1 or 2 indicators available for this report for

ecological processes, physical and chemical characteristics, or natural

disturbance regimes for grasslands and shrublands.

5-36 5.4 What Is the Ecological Condition of Grasslands and Shrublands? Chapter 5 - Ecological Condition
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.5 What Is the Ecological Condition of Urban and Suburban Areas? 5-37

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

Landscape Composition

Landscape Structure/Pattern

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Other Chemical Parameters

Trace Organics and Inorganics

Physical Parameters

Ecosystems and Communities

Surface and Ground Water Flows

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

Nitrate in farmland, forested and urban streams and ground water

Phosphorus in farmland, forested and urban streams

Chemical contamination in urban streams and ground water

Ambient concentrations of ozone, 8-hour and 1-hour

Patches of forest, grassland, shrubland, and wetland in 

urban/suburban areas

Extent of Ecological System/Habitat Types

DOI

DOI

DOI 

DOI 

EPA

Extent of urban and suburban lands USDA

Exhibit 5-22: Urban and suburban indicators

Essential Ecological Attribute Indicators Category Source

Landscape Condition I 2

5.5 What Is the Ecological

Condition of Urban and

Suburban Areas?

Urban and suburban ecosystems are areas where the majority of the

land is devoted to or dominated by buildings, houses, roads, concrete, grassy lawns, or other elements of human use and construction (The Heinz Center, 2002). Urban ecosystems are highly built-up

and paved over, resulting in more rapid changes in temperature,

runoff, and other variables than in more natural ecosystems. Plant

and animal life is heavily influenced by species introduced in horticulture and as pets, and native plant species might be more or less

completely removed from large areas and replaced by lawns, gardens,

and ornamentals (WRI, 2000). These areas generally show high levels of many air and water pollutants because of the concentration of

pollutant sources in small areas. Nonetheless, substantial biodiversity
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-38 5.5 What Is the Ecological Condition of Urban and Suburban Areas? Chapter 5 - Ecological Condition

can remain in these systems; for example, a 1993 survey identified

115 bird species in Washington, DC (Hadidian, et al., 1997).

There is substantial interest in understanding urban and suburban

ecosystems, as evidenced by two urban National Science Foundation

long-term ecological research sites (Phoenix and Baltimore), a professional journal, Urban Ecosystems and a number of recent writings

on the subject (Pickett, et al., 2001; Kinzig and Grove, 2001; Grimm,

et al., 2002). Much of urban ecosystems research is aimed not at

preserving natural ecosystems, but at “smart growth” and understanding how to enhance ecosystem services in a highly built environment. Despite the growing amount of research, the entire science

of urban ecosystem ecology is not sufficiently developed to have a

substantial number of ecological indicators. In addition, there may be

a lack of understanding regarding what to expect when applying indicators typically used in less built-up land cover classes to urban and

suburban ecosystems. The Heinz report lists eight indicators for

urban and suburban ecosystems, only two of which have adequate

data for national reporting.

Indicators for urban and suburban ecosystems used in this report are

listed in Exhibit 5-22, grouped according to essential ecological

attributes. Extent and chemical and physical condition data are the

most widely available. There were no indicators for biotic condition,

ecological processes, hydrology and geomorphology, or natural disturbance regimes for urban and suburban ecosystems suitable for

national or even regional reporting (The Heinz Center, 2002).

This section summarizes data related to urban and suburban ecosystems for five indicators, most of them relating to pollutant concentrations, that appear in earlier chapters. The section then introduces

one indicator that appears for the first time in this report—Patches

of Forest, Grassland, Shrubland, and Wetland in Urban/Suburban

Areas—which relates to the landscape essential ecological attribute.

The following indicators presented in previous chapters relate to the

ecological condition of urban and suburban areas:

Q The indicator Extent of Urban and Suburban Lands (Chapter 3,

Better Protected Land) was assessed using the National Land

Cover Database and estimating the proportion of the area in

1,000 foot pixels that fell into one of four developed land cover

types: low-intensity residential; high-intensity residential;

commercial-industrial-transportation; or urban and recreational

grasses (The Heinz Center, 2002). In 1992, urban and suburban

areas occupied about 32 million acres in the conterminous U.S. or

about 1.7 percent of the total land area (The Heinz Center,

2002). As with the estimate of the extent of farmlands, urban and

suburban areas are defined differently by different organizations,

sometimes using different data sources, thus affecting the area

estimates. For example, the Extent of Developed Lands indicator in

Chapter 3, Better Protected Land is based on USDA National

Resources Inventory delineation of developed lands, which is

about 98 million acres in the conterminous U.S., or about 4.3

percent of the total land area of the U.S., not including Alaska

(see Chapter 3, Better Protected Land).

Q The indicator Ambient Concentrations of Ozone, 8-hour and 1-hour

(Chapter 1, Cleaner Air) revealed that in 1999, about 55 percent

of the urban and suburban monitoring stations had high ozone

concentrations on 4 or more days, and that the percentage

fluctuated between 35 percent and 60 percent during the 1990s

(The Heinz Center, 2002). The number of sites with 10 days or

more of high ozone fluctuated between 20 and 30 percent of the

sites, with no apparent trend, but the number of sites with high

ozone on 25 days or more decreased from about 10 percent to

around 5 percent over the decade. Fluctuations are caused in part

by changes in the weather. As noted in the section on forests,

biomonitoring plots frequently reveal at least some ozone damage

to tree leaves.

Q The indicator Nitrate in Farmland, Forested, and Urban Streams and

Ground Water (Chapter 2, Purer Water), shows that 40 percent of

21 streams in which the predominant land use was urban and

suburban had nitrate concentrations above 1.0 ppm; 25 percent

had concentrations below 0.5 ppm; and 3 percent had

concentrations below 0.1 ppm (The Heinz Center, 2002).

Concentrations of nitrate in these urban streams were generally

lower than those of agricultural watersheds, but higher than those

in forested watersheds. 

Q The indicator Phosphorus in Farmland, Forested, and Urban Streams

(Chapter 2, Purer Water) showed that two-thirds of 21 urban

streams sampled had phosphorus concentrations of at least 

0.1 ppm, a level usually associated with excess algal growth (The

Heinz Center, 2002). About 10 percent of the urban streams had

concentrations of at least 0.5 ppm. 

Q According to the indicator Chemical Contamination in Streams and

Ground Water (Chapter 2, Purer Water), 85 percent of 21 urban

streams sampled had an average of about five detectable

contaminants throughout the year (The Heinz Center, 2002). All

of the streams had at least one chemical that exceeded guidelines

for the protection of aquatic life. For many urban and suburban

streams, the nutrient and contaminant signature is similar to the

signatures from agroecosystems (The Heinz Center, 2002;

Wickham, et al., 2002). 

The following indicator, Patches of Forest, Grassland, Shrubland, and

Wetland in Urban/Suburban Areas, provides data on landscape condition in urban and suburban areas.
Technical Document Q EPA’s Draft Report on the Environment 2003

Patches of forest, grassland, shrubland, and wetland in urban/suburban areas provide habitat for birds, amphibians, and small mammals. They also increase water infiltration and reduce temperature

by evapotranspiration. Patches of urban and suburban vegetation

generally reduce particulate matter, and they can increase or

decrease ozone concentrations, relative to built surfaces (Nowak,

et al., 2000). According to The Heinz Center (2002), the size of

patches of undeveloped land in urban and suburban areas is

important, with smaller patches generally considered to provide

poorer quality habitat. Recent studies have indicated a significant

loss of forest patch coverage in Atlanta and Baltimore in the last

several decades (American Forests, 2001, 2002).

What the Data Show

Around half of the undeveloped land in urban and suburban areas

occurs in patches smaller than 10 acres (Exhibit 5-23). Urban and

suburban areas in the Northeast have the largest percentage of

large (1,000 to 10,000 acres) patches of undeveloped land.

Patches of undeveloped land larger than 10,000 acres occur only

in urban and suburban areas of the West. 

Indicator Gaps and Limitations

Several limitations are associated with this indicator:

Q Natural patches may extend beyond the boundary of the

“urban and suburban area” land use class, which would cause

the size of the patches to be underestimated. 

Q Very small patches are difficult to distinguish if they are mixed

with developed classes, which also leads to underestimates. 

Q Remote sensing cannot distinguish between land that has

always been “non-urban” and patches, such as landfills, that

have reverted to grasslands or forest. 

Q Patch size is not the only factor that contributes to habitat

quality (The Heinz Center, 2002).

Data Source

The data source for this indicator was the National Land Cover

Database, Multi-Resolution Land Characterization Consortium

(1990s). (See Appendix B, page B-43, for more information.)

Indicator Patches of forest, grassland, shrubland, and wetland in urban/suburban areas – Category 2

Chapter 5 - Ecological Condition 5.5 What Is the Ecological Condition of Urban and Suburban Areas? 5-39 Percent of all “Natural” Lands

Coverage: lower 48 states

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. Data from 

Multi-Resolution Land Characteristics Consortium, and the USGS Earth Resources 

Observations Systems Data Center.

0

20

40

60

80

100

Northeast South Midwest W est

Exhibit 5-23: Patches of forest, grassland, shrubland, and 

wetland in urban and suburban areas, 1992

Less than 10 

acres

10 to 100 acres

100 to 1,000 

acres

1,000 to 10,000 

acres

Greater than 

10,000 acres
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-40 5.5 What Is the Ecological Condition of Urban and Suburban Areas? Chapter 5 - Ecological Condition

Summary: The Ecological Condition of Urban and Suburban

Ecosystems

Urban and suburban systems have been the subject of increasing

ecological interest, but their overall condition, nationally or even

regionally, is virtually unknown. 

Landscape condition

Within the technical limitations of using remote sensing data to

define urban and suburban ecosystems and the landscape patches

they contain, The Heinz Center (2002) has established a baseline

against which to judge current trends in urbanization. In 1992, urban

and suburban areas occupied about 32 million acres in the conterminous U.S. or about 1.7 percent of the total land area, but different

organizations, sometimes using different data sources, produce different estimates. For example, USDA National Resources Inventory

delineation of developed lands, estimates there to be about 

98 million acres in the conterminous U.S., or about 4.3 percent of

the total land area of the U.S., not including Alaska (see Chapter 3,

Better Protected Land). However, there is currently no firm plan in

place to collect the remote sensing data in the future to allow trends

to be calculated. Although the land use indicators identified provide

some useful information on extent, they do not address the actual

condition of those lands. Given the concentration of the human

population in developed areas of the country, a better understanding

of the interaction among humans and their developed environment

could help improve human health and the effects of developed lands

on ecological condition.

Chemical and physical characteristics

Chemical data from the NAWQA program used to develop the

stream quality indicator in this report and the Heinz report (2002)

include only 21 urban streams across the entire U.S. Nitrate and

phosphorus concentrations in these streams were intermediate

between farmlands and forest streams, but all of them had at least

one chemical that exceeded guidelines for the protection of aquatic

life. Given the numerous factors that can affect these systems, 

21 streams are not likely to be an adequate baseline against which

to track the progress of environmental protection activities, including

stormwater management, controls on non-point source pollution

from lawns, golf courses, and septic systems, with any statistical certainty. An indicator of the extent of impervious surfaces might be

useful for inferring non-point source pollution impacts.

There were no Category 1 or 2 indicators available for this for biotic

condition, ecological processes, or natural disturbance regimes. The

Heinz Center (2002) identified several indicators that could be

promising but for which there are not even regional data:

Q An indicator that would report on the percentage of urban and

suburban areas in which <25 percent, 25 to 50 percent, 50 to 

75 percent, and >75 percent of the original species had been 

lost or displaced.

Q An indicator that would report on the number of nuisance species

in urban and suburban areas (e.g., white-tailed deer, kudzu).

Q Fish Index of Biotic Integrity (IBI) and Macroinvertebrate Biotic

Integrity Index (MBII) indicators in urban/suburban streams.

Q An indicator that would report on the coverage of stream bank

vegetation. 

The lack of national biotic indicators for urban fresh water systems

makes it particularly difficult to measure national progress in maintaining balanced communities in urban streams.

A particular problem in urban and suburban systems is establishing

appropriate reference conditions for biological structure and ecosystem function measures (The Heinz Center, 2002). For example,

expecting fish and invertebrate communities in urban streams to be

typical of relatively undisturbed forest or grassland ecosystems

would be unrealistic. Data are insufficient on both the current status

of species and the original species present to calculate the number

of native species lost. As another example, an indicator tracking

national trends in urban stream buffers would be particularly helpful

to states tracking the effectiveness of watershed management programs. However, a decision would be needed on a threshold for

buffer strips of adequate width to protect stream channels, and further development of satellite measurements would be needed before

such an indicator could be used for national reporting. 

A potentially useful hydrology/geomorphology indicator would be

the percentage of impervious area (The Heinz Center 2002).

Impervious areas generally increase runoff from rain events, leading

to modified stream channels, increased stream temperatures,

decreased infiltration, and pollutants carried into ecosystems 

(e.g., Booth and Jackson, 1997). According to The Heinz Center,

however, although some local governments collect data on impervious surfaces, it is difficult to measure (Arnold and Gibbons, 1996),

and there are insufficient data on this indicator for national reporting. Tracking impervious surface changes may be important for measuring progress in reducing the impact of stormwater runoff on the

quality of receiving streams.

Another potentially useful indicator is the urban heat island 

(The Heinz Center 2002). Urban heat islands raise the ambient temperature surrounding both terrestrial and aquatic ecosystems.

Because chemical and biological reaction rates are temperature

dependent, increased heating and temperatures can increase the

stress on all biological species, both directly and indirectly. Dissolved

oxygen saturation is lower in warmer water, so aquatic organisms,

with higher metabolic rates and the need for greater oxygen supplies,

have less oxygen available in the water because of lower oxygen saturation in warm water. The heat island effect can also have important

impacts on air quality in urban and downwind areas (Nowak, et al.,

2000). Again, the data may be available to calculate this indicator,

but it has not been developed nationally. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-41

5.6 What Is the

Ecological Condition of

Fresh Waters?

Fresh waters include wetlands, lakes and reservoirs, and streams and

rivers. Wetlands are areas where saturation with water is the dominant factor determining the types of plant and animal communities.

Wetlands vary widely because of differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors. Two

general categories of wetlands are recognized: coastal (tidal) wetlands and inland (non-tidal) wetlands. Wetlands have been threatened by outright loss and conversion from one type to another, but

programs designed to restore or enhance wetlands, such as the

Wetlands Reserve Program, as well as state, local, and private initiatives on agricultural lands, have resulted in reduced losses 

(see Chapter 2, Purer Water).

The U.S. contains more than 3.7 million miles of streams and rivers.

About 60 percent of all these stream miles are found in small, headSAB Framework

Landscape Condition

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I 2

Indicators Category Source

Exhibit 5-24: Fresh water indicators

Extent of Ecological System/Habitat Types

Landscape Composition

Landscape Structure/Pattern

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Trace Organic and Inorganic Chemicals

Wetland extent and change

Extent of ponds, lakes, and reservoirs

Altered fresh water ecosystems

Non-native fresh water fish species

Animal deaths and deformities

Phosphorus in large rivers

At-risk fresh water plant communities

Fish Index of Biotic Integrity in streams

Acid sensitivity in lakes and streams

Chemical contamination in streams

Changing stream flows

Sedimentation index

DOI

DOI

DOI

DOI

DOI

NatureServe

EPA

Macroinvertebrate Biotic Integrity Index for streams

Contaminants in fresh water fish 

EPA

DOI

Ecosystems and Communities

Surface and Ground Water Flows

Other Chemical Parameters

Physical Parameters

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

DOI

Lake Trophic State Index EPA

DOI

EPA

DOI

EPA

Species and Populations At-risk native fresh water species NatureServe
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-42 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

water streams. The U.S. also contains more than 60 million acres of

lakes, ponds, and reservoirs. Natural lakes are generally located in

previously glaciated areas of the Northeast and Midwest, in mountainous areas, and as sinkholes or seepage lakes in Florida. Oxbow

lakes are associated with former meanders of river systems.

Reservoirs predominate in the West and in the unglaciated areas of

the South and Southeast. Ponds, both manmade and natural, are

found throughout the U.S. (see Chapter 2).

Many of the problems facing fresh water systems are similar: low dissolved oxygen, eutrophication, acidification, toxic materials in air

deposition (e.g., mercury), point and non-point discharges and sediments, siltation, hydrologic modification, temperature modification,

effects of Ultraviolet-B (UV-B) radiation, invasive species, overfishing,

and more recently, endocrine-disrupting chemicals (e.g., Naiman and

Turner, 2000). According to the most recent 305(b) report required

bi-annually under the Clean Water Act, approximately one-half of the

lakes and slightly more than one-half of the streams assessed by the

states do not meet the designated use assigned to them by the state

in which they are located (EPA, OW, August 2002).11

There have been several systematic efforts over the past three

decades to report on the condition of lakes and stream ecosystems

with respect to some of these issues:

Q The U.S. Fish and Wildlife Service (USFWS) conducted the

National Fisheries Survey to determine the condition of fish

communities in the nation’s streams (Judy, et al., 1984). The

survey used a probability design, and fish community condition

was based on expert opinion, rather than collection of field data. 

Q The National Surface Water Survey (NSWS) used a probability

design to assess the acidity of lakes and streams in all areas of the

U.S. sensitive to acid deposition (NAPAP, 1991; Baker, et al., 1991;

Kaufmann, et al., 1991). 

Q The Temporally Integrated Monitoring of Ecosystems (TIME)

program has continued monitoring a representative sample of acid

sensitive lakes and streams, in the Northeast and Appalachians

(Stoddard, et al., 1999). 

Q The National Water Quality Assessment (NAWQA) network

samples surface fresh water ecosystems in 50 watersheds, and

makes measurements of chemistry and biota

(<http://water.usgs.gov/nawqa/>). 

Q The Environmental Monitoring and Assessment Program (EMAP)

conducted a pilot survey of streams in the mid-Atlantic states,

measuring chemistry and biota (Herlihy, et al., 2000). Surveys are

ongoing in the western states and have just begun in large river

systems of the mid-continent. 

This substantial experience has contributed progress in monitoring

ecological condition in lakes and streams, but there are still few

Category 1 indicators.

Exhibit 5-24 shows the fresh water indicators used in this report,

grouped according to the essential ecological attributes. Nine of

these indicators are discussed in the previous chapters. This section

briefly summarizes those indicators, and then introduces seven new

ones. There are no indicators available for national or regional

reporting for ecological processes or natural disturbance regimes

(The Heinz Center, 2002). Indicators presented in previous chapters

include:

Q The indicator Wetland Extent and Change (Chapter 2, Purer Water)

shows that since European settlement of the conterminous U.S.,

more than half of the original 220 million acres of wetlands have

been drained and filled. Wetland types include fresh water forested,

shrub, and emergent wetlands, plus open water ponds. By 1997,

total wetland acreage was estimated to be 105.5 million acres (Dahl,

2000). Of that total, nearly 95 percent or 100.2 million acres were

fresh water, and about 5 percent or 5.3 million acres were intertidal

marine and estuarine. Rates of annual wetland losses have been

dropping from almost 500,000 acres a year three decades ago to

less than 100,000 acres averaged annually since 1986. The loss rate

between 1986 and 1997 was estimated to be 58,500 acres per

year, an 80 percent reduction in the rate of loss from the previous

decade. 

A related ecological impact has been the conversion of one

wetland type to another, such as clearing trees from a forested

wetland or excavating a shallow marsh to create an open water

pond. Open water ponds, which have more than doubled in area

since the 1950s, are not the ecological equivalent of fresh water

emergent marshes. Such conversions change habitat types and

community structure in watersheds and impact the animal

communities that depend on them. 

Urban development accounted for an estimated 30 percent of all

wetland losses. Estimates for the other loss categories included 

26 percent to agriculture, 23 percent to silviculture, and 21 percent

to rural development. An estimated 98 percent of all wetlands

converted to other uses were fresh water wetlands (Dahl, 2000).

Forested and emergent wetlands make up over 75 percent of all

fresh water wetlands. Since the 1950s, fresh water emergent

wetlands have declined by nearly 24 percent, more than any

other fresh water wetland type. Fresh water forested wetlands

have sustained the greatest overall losses—10.4 million acres

since the 1950s. 

Q Physically altering a fresh water body to increase some other

benefit (e.g., flood control, navigation, reduced erosion, or

increased area for farming or development) also may change fish

11While these statistics are reported biannually, because the states use

different measures and monitoring designs, the results do not provide a comparable and consistent picture of the condition of lakes and streams nationally (USGAO, 2000). See Section 2.2.1 for a discussion of recent progress on

this issue.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-43

and wildlife habitat, disrupt patterns and timing of water flows, act

as barriers to animal movement, or reduce or increase natural

filtering of sediment and pollutants. The indicator Altered Fresh

Water Ecosystems (Chapter 2, Purer Water), reveals that 23 percent

of the banks of both rivers and streams (riparian areas) and lakes

and reservoirs have either croplands or urban development in the

narrow area immediately adjacent to the stream. Data on the

degree to which streams and rivers are channelized, leveed, or

impounded are not available. According to Dahl (2000), 

78,100 acres (31,600 hectares) of forested wetlands were

converted to fresh water ponds. Conversions of forested wetlands

to deep water lakes resulted from human activities by either

creating new impoundments or raising the water levels on existing

impoundments, thus killing the trees.

Q The indicator Contaminants in Fresh Water Fish (Chapter 2, Purer

Water) reported on contaminants in fish tissue for the entire U.S.,

including polychlorinated biphenyls (PCBs), organochlorine

pesticides, and trace elements (The Heinz Center, 2002). The

presence of contaminants can be harmful to the organisms

themselves, or can affect reproduction, and they can make fish

unsuitable for consumption. Half of the fish tested had at least

five contaminants at detectable levels, and approximately the same

number had one or more contaminants at levels that exceeded the

aquatic life guidelines.

For Mid-Atlantic Highland streams with sufficient fish tissue for

analysis (44 percent of stream miles did not have sufficient

quantities of fish tissue), about 4 percent of the stream miles had

fish tissue mercury concentrations that exceeded wildlife criteria

(EPA, ORD, Region 3, August 2000). 

Q For the the indicator Phosphorus in Large Rivers (Chapter 2, Purer

Water), The Heinz Center (2002) reports that half of the rivers

tested had total phosphorus concentrations of 100 ppb or higher.

This concentration (100 ppb) is EPA’s recommended goal for

preventing excess algal growth in streams that do not flow directly

into lakes. None of the rivers had concentrations below 20 ppb, a

level generally held to be free of negative effects (EPA, OW,

November 1986). Data were insufficient to report on lakes and

reservoirs nationally.

Q The indicator Lake Trophic State Index (Chapter 2, Purer Water)

assessed the nutrient or total phosphorus (TP) concentrations in

northeast lakes (Peterson, et al., 1998). Once phosphorus enters

lakes, it frequently serves as the nutrient that limits the growth of

nuisance blooms of phytoplankton (algae). National data on lake

trophic condition are not available. However, regional patterns of

lake trophic condition were assessed for a target population of

11,076 Northeast lakes sampled as part of the EPA EMAP during

summers from 1991 to 1994 using the Lake Trophic State Index. It

was found that 37.9 percent (±8.4 percent)12 of the lakes were

oligotrophic (TP<10 ppb), 40.1 percent (±. 9.7 percent) were

mesotrophic (10<TP<30 ppb), 12.6 percent (±.7.9 percent) were

eutrophic (30<TP<60 ppb), and 9.3 percent (±.6.3 percent) were

hypertrophic (TP>60 ppb) (Peterson, et al., 1998). 

Q The indicator Chemical Contamination in Streams and Ground Water

(Chapter 2, Purer Water), revealed that all the streams sampled by

the NAWQA program had one or more contaminants at detectable

levels throughout the year, and 85 percent had five or more (The

Heinz Center, 2002).13 Three-fourths of the streams tested had one

or more contaminants that exceeded aquatic life guidelines. Onefourth of the streams exceeded the standards for four or more

contaminants. Nearly all of the stream sediments tested had an

average of five or more contaminants (PCBs, polycyclic aromatic

hydrocarbons [PAHs], other industrial chemicals and trace elements)

at detectable levels, and half had one or more contaminants that

exceeded aquatic life guidelines. Half of the fish tested had at least

five contaminants (PCBs, organochlorine pesticides, and trace

elements) at detectable levels, and approximately the same number

had one or more contaminants at levels that exceeded the aquatic

life guidelines (The Heinz Center, 2002).14

Q The indicator Acid Sensitivity in Lakes and Streams (Chapter 2,

Purer Water) is affected by the natural buffering capacity of the

soil and the rate of acid deposition from the atmosphere. The

National Surface Water Survey (NSWS) (Landers, et al., 1988;

Linthurst, et al., 1986; Messer, et al., 1986, 1988) determined that

4.2 percent of the NSWS lakes and 2.7 percent of NSWS streams

were acidic (Acid Neutralizing Capacity <0 μeq/L) (Baker, et al.,

1991). Almost 20 percent (19.1 percent) of NSWS lakes and

11.8 percent of NSWS streams were susceptible to acidic

deposition (ANC < 50 μeq/L) (Baker, et al., 1991).15 Of the acidic

NSWS lakes, 75 percent were classified as acidic from acid

deposition, 22 percent were organic acid dominated, and

3 percent were acidic from watershed sulfur sources. Of the acidic

stream reaches, 70 percent were acidic from acid deposition,

29 percent were organic acid dominated, and 1 percent were

acidic from watershed sulfur sources (Baker, et al., 1991).

These surveys have been repeated periodically for smaller

probability samples of lakes in the Northeast, the Adirondacks,

and streams in the Appalachians (Stoddard, et al., 1996). More

intensive monitoring also has been conducted on lakes in the

Northeast, the Appalachians, and the Midwest, and on streams in

the Appalachian Plateau and Blue Ridge to assess long-term

acidification trends (Stoddard, et al., 1998). Based on these

12 Concentrations in parentheses represent the 95 percent confidence

interval.

13 Nitrate, ammonium, and trace metals were not included in the occurrence analysis, because they occur naturally (Heinz(The HeinzCenterHeinz

Center, 2002, p.50).

14Additional information on chemical contamination in all waters of the

U.S. is provided in the technical notes, pp. 210-214, of the Heinz report

(2002).

15There were regional differences in these percentages: only 0.1 percent of NSWS lakes in the West and Florida were sensitive, but 22.7 percent

of Northern Appalachian streams were sensitive.
programs, EPA estimated that in three regions, one-quarter to

one-third of lakes and streams previously affected by acid rain

were no longer acidic, although they were still highly sensitive to

future changes in deposition (EPA, ORD, January 2003).

Specifically:

Q Eight percent of lakes in the Adirondacks are currently acidic,

down from 13 percent in the early 1990s.

Q Less than 2 percent of lakes in the Upper Midwest are

currently acidic, down from 3 percent in the early 1980s. 

Q Nine percent of the stream length in the Northern

Appalachian Plateau region is currently acidic, down from 

12 percent in the early 1990s.

Lakes in New England registered insignificant decreases in acidity,

and streams in the Ridge and Blue Ridge regions of Virginia were

unchanged. The Ridge and Blue Ridge regions are expected to

show a lag time in their recovery due to the nature of their soils,

and immediate responses to decreasing deposition were neither

seen nor expected. The NSWS has not been repeated nationwide,

so no data exist to assess trends in surface water acidification in

other sensitive areas of the country.

Q The indicator Changing Stream Flows is one of two indicators

presented in Chapter 2, Purer Water that are associated with fresh

water hydrology and geomorphology and relate to the ecological

condition of fresh water. Changes in stream flow can result in

significant effects on fish habitat and chemical concentrations in

streams. According to The Heinz Center (2002), the percentage

of streams and rivers with major changes in the high or low flows

or timing of those flows increased slightly from the 1970s to the

1990s, but the number with high flows well above the high flows

between 1930 and 1949 increased by approximately 30 percent

in the 1990s. The earlier 1930 through 1949 period included

some droughts, but much of it also preceded widespread dambuilding and irrigation projects.

Q The greatest stressor to mid-Atlantic streams, and many other

streams throughout the U.S., is altered instream habitat (EPA,

ORD, Region 3, August 2000). A Sedimentation Index (Chapter 2,

Purer Water) was developed for Mid-Atlantic Highland streams to

assess the quality of instream habitat for supporting aquatic

communities (Kaufmann, et al., 1999). The amount of fine

sediments on the bottom of each stream was compared with

expectations based on each stream’s ability to transport fine

sediments downstream (a function of the slope, depth and

complexity of the stream). When the amount of fine sediments

exceeds expectations, it suggests that the supply of sediments

from the watershed to the stream is greater than what the stream

can naturally process. Streams with levels of fine particles at least

10 percent below the predicted value were rated to be in “good”

condition relative to the sedimentation criteria. Those with levels

from 10 percent below to 20 percent above the predicted value

were rated “fair.” Those with levels more than 20 percent above

regional mean expectations were rated “poor.” Based on the

Sedimentation Index, about 35 percent of the stream miles had

good instream habitat, 40 percent had fair instream habitat, and

25 percent of the stream miles had poor instream habitat (EPA,

ORD, Region 3, August 2000).

Several indicators presented for the first time in this report are

described below. They include a Category 1 indicator related to

landscape condition and six Category 2 indicators relating to biotic

condition. There were no indicators for ecological processes or natural disturbance regimes.

5-44 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-45

This indicator reports the area of ponds, lakes, and reservoirs in

the conterminous U.S., excluding the Great Lakes. Over the long

term, changes in this indicator reflect the effects of climate on

water levels in existing lakes, ponds, and reservoirs, and of reservoir construction, destruction, and management. 

What the Data Show

The Heinz Center (2002) reports that, excluding the Great

Lakes, the conterminous U.S. contains 21 million acres of lakes,

ponds, and reservoirs. The number of ponds (small water bodies

usually less than 20 acres and 6 feet deep) increased by 100

percent since the 1950s (Exhibit 5-25). For unknown reasons,

the rate of lake and reservoir creation declined 43 percent from

the 1970s to 1980s; deep water lakes and reservoirs showed a

modest but statistically unreliable increase between the 1980s

and 1990s (Dahl, 2000).

Indicator Gaps and Limitations

The USGS National Hydrography Dataset identifies a considerably

larger area of lakes, reservoirs, and ponds at least 6 acres in size

(26.8 million acres), and the cause of the discrepancy is unknown

(The Heinz Center, 2002).

Data Source

The data source for this indicator was the National Wetlands

Inventory, U.S. Fish and Wildlife Service (1970-2000). 

(See Appendix B, page B-43 for more information.)

Indicator Extent of ponds, lakes, and reservoirs – Category 1 Millions of Acres

Coverage: lower 48 states. 

Note: Lake area does not include the Great Lakes, which 

cover about 60.2 million acres within the United States.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Fish and Wildlife Service's National Wetlands Inventory.

0

4

8

12

16

1950 1960 1970 1980 1990 2000

Lakes and 

Reservoirs

Ponds

Exhibit 5-25: Extent of ponds, lakes, and reservoirs, 1950s-1990s
EPA’s Draft Report on the Environment 2003 n Technical Document

5-46 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

The U.S. was sufficiently concerned about preserving species to

enact the Endangered Species Act in 1973 to provide legal protection for species that were endangered or threatened. Many of

these species depend on lakes, streams, and adjoining wetlands

for their continued existence. It is impossible to monitor all freshwater species, but this indicator reports on species of fish,

amphibians, reptiles, aquatic mammals, butterflies, mussels, snails,

crayfish, fresh water shrimp, dragonflies, damselflies, mayflies,

stoneflies, and caddisflies that are at various degrees of risk of

extinction (The Heinz Center, 2002).

What the Data Show

According to The Heinz Center (2002), approximately 13 percent of native fresh water species are critically imperiled, 8 percent are imperiled, 11 percent are vulnerable, and 4 percent are

or might be extinct (Exhibit 5-26). Critically imperiled species

are typically found at no more than five places, and may have

suffered steep declines or very high risk. Vulnerable species may

be found in 20 to 80 locations and show widespread declines

or moderate levels of risk (Stein, 2002). Mussels and fish are

particularly at risk. Hawaii and the Southeast have significantly

higher percentages of at-risk species than other regions, but this

condition may be partially the result of Hawaii and parts of the

Southeast having a higher number of naturally rare species (The

Heinz Center, 2002).

Indicator Gaps and Limitations

The data underlying this indicator are not from a site-based monitoring program, but rather from a census approach that focuses

on the location and distribution of at-risk species. The data do

not distinguish species that are naturally rare from species that

have become rare because of human actions, making it difficult to

distinguish actual trends in this indicator.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from 

NatureServe Explorer database. (See Appendix B, page B-43, for

more information.)

Indicator At-risk fresh water native species – Category 2
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-47

This indicator reports on the percentage of watersheds with different numbers of non-native species with established breeding

populations (The Heinz Center, 2002). Non-native species

include species not native to North America and species that are

native to this continent but are now found outside their historic

range. Such species, once introduced from some other location,

often lack predators or parasites that kept them in check in their

native habitats, and expand to cause a degree of ecological and

economic disruption. Some non-native species are introduced

intentionally (e.g., rainbow trout). 

What the Data Show

Data are currently available nationally only for fish: of 350 watersheds (6-digit HUCs) in the U.S., only five have no non-native fish

(The Heinz Center, 2002). Sixty percent have 1 to 10 non-native

species, and two watersheds have 41 to 50 non-native fish species

(Exhibit 5-27).

Indicator Gaps and Limitations

The data are not from a site-based monitoring program; they

rely for the most part (90 percent) on the published literature

and (10 percent) direct reporting by governmental and private

biologists. New discoveries are not always reported (The Heinz

Center, 2002).

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from the 

Non-indigenous Aquatic Species database. (See Appendix B, 

page B-44, for more information.)

Indicator Non-native fresh water fish species – Category 2

Exhibit 5-27: Non-native fresh water fish species, 2000

Number of Species

0

1–10

11–20

21-30

31-40

41-50

Coverage: lower 48 states.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Geological Survey.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-48 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

Unusual mortality events (e.g., fish kills) or deformities (e.g., frog

deformities) can have economic consequences, and they are also

seen as evidence that something is wrong (e.g., a contaminant is

present, or the organisms are under stress from some other

source). Although data are collected on die-offs of mammals, fish,

and amphibians, and on amphibian deformities, data are insufficient for national reporting (The Heinz Center, 2002). This indicator reports on unusual mortality events for waterfowl only.

What the Data Show

From 1995 to 1999, approximately 500 incidents of unusual

waterfowl mortality were reported (The Heinz Center, 2002)

(Exhibit 5-28). In slightly more than 20 percent of the incidents,

more than 1,000 birds died, and in 15 of the incidents, more than

10,000 birds died. The total number of die-offs reported from

1995 to 1999 was 20 percent lower than the numbers reported in

two earlier periods (1985 to 1989 and 1990 to 1994) (The

Heinz Center, 2002). A larger number of events were reported in

the Pacific and Midwest regions; fewer were reported in the

Southwest and Southeast. 

Indicator Gaps and Limitations

The data are not from a defined site-based monitoring program,

but are provided by various sources such as state and federal personnel, diagnostic laboratories, wildlife refuges, and published

reports, as they are discovered or reported (The Heinz Center,

2002). This makes it hard to distinguish real trends from trends in

reporting.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from the 

National Wildlife Health Center database. 

(See Appendix B, page B-44, for more information.)

Indicator Animal deaths and deformities – Category 2

Partial Indicator Data: Waterfowl Mortality Only

Number of Mortality Events 

for 5-year Period

Exhibit 5-28: Animal deaths and deformities, 1985-1999

0

100

200

300

400

1985-1989 1990-1994 1995-1999

Number of 

Birds in Event

<100

100 to 1,000

1,000 to 10,000

>10,000

Data Not Adequate for National Reporting on:

Q Fish Die-offs

Q Mammal Die-offs

Q Amphibian Die-offs

Q Amphibian Deformities

Coverage: all 50 states, Puerto Rico, and the U.S. Virgin Islands

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the U.S. Geological Survey.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-49

The Heinz report employs an indicator of the threat of elimination

of wetland and riparian area plant communities. This indicator

uses an expert assessment conducted by NatureServe (Stein,

2002) of factors such as the remaining number and condition of

the community, the remaining acreage, and the severity of threats

to the community type. 

What the Data Show

According to this indicator, 12 percent of the 1,560 wetland communities ranked are critically imperiled, 24 percent are imperiled,

and 25 percent are vulnerable (The Heinz Center, 2002) 

(Exhibit 5-29).

Indicator Gaps and Limitations

The Heinz report states that data are not adequate for national

reporting (The Heinz Center, 2002). The report concludes that

technical challenges in classifying riparian communities prevent

national estimates for stream bank plant communities. In addition,

interpreting the data is complicated because some species are

naturally rare, and the total number of species for any ecosystem

is unknown.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from

NatureServe Explorer database. (See Appendix B, page B-44, for

more information.)

Indicator At-risk fresh water plant communities – Category 2

Partial Indicator Data: Wetlands

Percent of Fresh Water 

Communities

0

20

40

60

80

100

2000 Future

Exhibit 5-29: At-risk fresh water plant communities, 2000

Critically

Imperiled

Imperiled

Vulnerable

Total At-Risk

Data Not Adequate for National Reporting on Riparian Communities

Coverage: excludes Alaska.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from NatureServe and its Natural Heritage member programs. 
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-50 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

Fish communities integrate the effects of the physical, chemical,

and biological stressors in the environment. The Heinz Center

(2002) listed the status of fresh water animal communities as an

indicator in need of development. Karr, et al. (1986, 1997) developed a Fish Index of Biotic Integrity (IBI) that incorporates

species richness, trophic composition, reproductive composition,

and abundance and individual health of fish communities in

streams. This index, modified by McCormick, et al. (2001), was

applied to a regional survey of streams in the mid-Atlantic states,

and provides an example of an indicator that could be applied

nationally.

A sample of reference sites that represented the best conditions

observable today in the mid-Atlantic region (e.g., sites free of

influences from mine drainage, nutrients, habitat degradation)

provided a frame of reference for ranking the condition of streams

overall. The IBI scores calculated for the reference sites ranged

from 57 to 98. The 25th percentile of this distribution (IBI=72)

was used to distinguish sites that were in good condition from

those in fair condition. The first percentile value (IBI=57) separated sites in fair condition from those in poor condition. A statistical way to describe this setting of thresholds is to say that

any IBI score of less than 57 in a sampled stream is 99 percent certain to be below the range of values seen in reference sites (McCormick, et al., 2001).

What the Data Show

Fish were collected at probability sites that represent about

90,000 miles of streams in the mid-Atlantic. The fish IBI

indicated that 27 percent of the streams were in good condition and 14 percent were in poor condition in the MidAtlantic Highlands (see Exhibit 5-30). About 38 percent of

the streams were scored in fair condition. No fish were

caught in about 21 percent of the streams. The estimates

of stream condition have a confidence interval of about

±.8 percent (McCormick, et al., 2001).

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q Condition cannot be assessed in streams where no fish were

caught. Poor condition cannot be inferred from no fish caught,

because some streams were likely too small to support a fishery.

Data were insufficient to indicate if the stream had poor quality

or simply no fish (EPA, ORD, Region 3, August 2000). 

Q The data are available only for a limited geographic region, and

no repeated sampling is available to estimate trends.

Data Source

The data source for this indicator was the Mid-Atlantic Highlands

Streams Assessment, Environmental Protection Agency, August

2000, using data from the Mid-Atlantic Integrated Assessment.

(See Appendix B, page B-45, for more information.)

Indicator Fish Index of Biotic Integrity in streams – Category 2

Exhibit 5-30: Fish Index of Biotic Integrity (IBI) 

indicators used to assess stream condition in the 

Mid-Atlantic Highlands, 1993-1996

27%

Good

38%

Fair

14%

Poor

21%

No fish

caught

Coverage: Mid-Atlantic Highlands

Note: No fish caught does not indicate poor condition. Some streams 

naturally do not have fish.

Source: McCormick, F. H. et al. Development of an Index of Biotic Integrity for the 

Mid-Atlantic Highlands Region. 2001.
Technical Document Q EPA’s Draft Report on the Environment 2003

Like fish, macroinvertebrate communities integrate physical, chemical, and biological stressors, but because many of them are more

sedentary than fish and occupy different ecological niches, they

provide a complementary picture of ecological condition. 

A Macroinvertebrate Biotic Integrity Index (MBII) was developed

for mid-Atlantic streams by Klemm, et al. (2002, 2003). The MBII

incorporates taxa richness, assemblage composition, pollution tolerance (includes all maroinvertebrates, not just insects), and functional feeding groups (Klemm, et al., 2002). Similar to the

approach used to separate the Fish IBI scores (McCormick, et al.,

2001), the 25th percentile of the reference site MBII scores was

used to distinguish sites in good condition from those in fair condition. The first percentile was used to separate sites in fair condition from those in poor condition (McCormick, et al., 2001).

What the Data Show

The MBII scores indicated that 17 percent of the streams in the

mid-Atlantic were in good condition, 57 percent were in fair condition, and 26 percent were in poor condition (Exhibit 5-31).

Indicator Gaps and Limitations

The data are available only for a limited geographic region, and no

repeated sampling is available to estimate trends.

Data Source

The data source for this indicator was Development and Evaluation

of a Macroinvertebrate Biotic Integrity Index (MBII) for Regionally

Assessing Mid-Atlantic Highlands Streams. 2003, Klemm, et al.,

using data from the Mid-Atlantic Integrated Assessment. (See

Appendix B, page B-45, for more information.)

Indicator Macroinvertebrate Biotic Integrity Index for streams – Category 2

Chapter 5 - Ecological Condition 5.6 What is the Ecological Condition of Fresh Waters? 5-51

Exhibit 5-31: 

Macroinvertebrate Biotic Integrity Index (MBII), 

Mid-Atlantic Highlands, 1993-1996

Coverage: Mid-Atlantic Highlands

Source: Klemm, D.J., et al. Development and Evaluation of a Macroinvertebrate Biotic 

Integrity Index (MBII) for Regionally Assessing Mid-Atlantic Highlands Streams. 2003.

17%

Good

57%

Fair

26%

Poor
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-52 5.6 What is the Ecological Condition of Fresh Waters? Chapter 5 - Ecological Condition

Summary: The Ecological Condition of Fresh Waters

Fresh water systems are under pressure from point and non-point

pollution, atmospheric deposition, altered habitat, and invasive

species. A review of Exhibit 5-24, however, indicates that there are

virtually no Category 1 indicators or monitoring programs that provide a national picture of the ecological condition of fresh waters.

No national condition data are available on ecological processes, not

are there any nationally or regionally reported indicators of natural

disturbance regimes.

Landscape condition

The National Wetlands Inventory provides unbiased statistical estimates of the extent of wetlands, ponds, lakes, and reservoirs in the

conterminous U.S. at decadal scales since the 1970s. There is no

similar effort for the extent of streams (losses can occur because of

mining, damming, water withdrawal, or climate change). Chapter 2,

Purer Water, estimates that the U.S. has more than 3.7 million miles

of streams and rivers (EPA, OW, June 2000a, 2000b). About

60 percent of all these stream miles are found in small, headwater

streams. The Heinz Center reports, however, that because there is no

agreed-upon system to classify streams (e.g., by discharge, drainage

area, or stream order), there are no national data sets for reporting

on stream size.

Biotic condition

At this time, no national condition data are available on lake, wetland, or stream biota. The USGS National Water Quality Assessment

(NAWQA) program has collected data on the biota in rivers and

streams in the network, but no analysis has been performed on the

data at a national level (USGS, 2002; <http://water.usgs.gov/

nawqa/>). Surveys of stream benthos and fish communities have

been conducted for the mid-Atlantic region that provide unbiased

estimates of the condition of 90 percent of the streams in the

region. Both surveys showed only 17 percent (±8 percent) of the

streams to be in good condition, but there is no indication of

whether they are the same streams or of the likely cause(s) of

impairment. No fish were caught in 16 percent of the streams, so

their condition could not be judged based on this criterion. Similar

regional studies have been conducted in the western states, but the

data have not yet been reported. There are no nationally or 

regionally representative data on the aquatic communities of lakes.

Based on NatureServe data, 36 percent of aquatic biota in several

categories are either extinct or at some risk of extinction, but

because this database relies on voluntary reporting, future trends

might not be discernable with statistical reliability. NAWQA collected

contaminant data from fish tissue in 223 streams, and almost half

showed concentrations that exceeded aquatic life guidelines for at

least one contaminant. However, these data have not been related to

the condition of the fish communities in the corresponding streams,

so ecological condition cannot be determined. There are no specific

plans to re-sample in any of these programs, and so there is no

assurance that trend data will be available in the future.

Chemical and physical characteristics

Better data are available for chemical and physical characteristics of

streams, less for lakes, and none for wetlands. The NAWQA program

reports data on total phosphorus concentrations in more than 

140 large rivers nationwide, but there are no corresponding national

data on either lake or reservoir concentrations (where algal blooms

are likely to develop), nor on the corresponding biological communities. Reliable regional estimates have been made of total phosphorus

concentrations in 11,076 lakes in the Northeast states. These estimates showed with a high degree of confidence that fewer than 22

percent of the lakes were estimated to be eutrophic or hypertrophic.

While a relationship exists between total phosphorus concentrations

and algal biomass or productivity (Carlson, 1977), lake-to-lake variation is considerable, so none of these data truly express the known

ecological condition of these lakes or rivers with respect to eutrophication. Nitrate is not often a limiting nutrient in fresh waters, so it

provides little ecological information on fresh waters themselves

(although it does provide useful information on the watershed, as

discussed in the sections on forests and farmlands).

The NAWQA program reports on contaminants in stream waters

from 109 streams, and sediments from 558 stream sites across the

U.S. At least half of the streams had concentrations that exceeded

wildlife criteria, but there are as yet no analyses relating these to the

condition of fish or invertebrate communities in the streams naturally. Incorporation of water quality data monitored by the states could

improve the coverage, if care is given to representative sampling and

comparable methods and indicators. 

A national survey in the 1980s provided estimates of the sensitivity

of all lakes and all streams in the eastern U.S. to acidic deposition

(Landers, et al., 1988; Kaufmann, et al., 1991). Periodic resurveys

and intensive sampling of representative lakes and streams have

allowed EPA to conclude that, because of reductions in sulfate emissions under its acid rain regulations, one-quarter to one-third of

lakes and streams in three regions affected by acid rain are no longer

acidic (EPA, ORD, Region 3, August 2000). Corresponding biological community data exist only for streams in the Mid-Atlantic

Highlands. 

Hydrology and geomorphology

There are nationally reported data on only one hydrologic/geomorphological indicator: changing stream flow. This indicator is reported

on all rivers and streams for which the record of data is adequate,

and it shows that high flows have increased during the past decade.

There are no corresponding data to indicate why, however, nor are

there data on any accompanying change in the fish communities, so

ecological condition cannot be assessed with any reliability. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-53

There were no Category 1 or 2 indicators available for ecological

processes or natural disturbance regimes for fresh waters. Limnologists

have long measured primary productivity in lakes, and nutrient spiraling and leaf-pack decomposition in streams, but no systematic data

were available in the form of an indicator for this report. Phenomena

involved in natural disturbance regimes in fresh waters include

hydrology (e.g., low-flow frequencies, floods), time of ice-out in

lakes, and fires and other factors that affect watersheds. 

5.7 What Is the

Ecological Condition of

Coasts and Oceans?

The coasts and oceans of the United States extend from the

shoreline out approximately 200 miles into the open ocean. The

indicators in this report, however, focus on estuaries and coastal

waters within 25 miles of the coast. Coastal ecosystems are productive and diverse, and include estuaries, coastal wetlands, coral

reefs, mangrove forests, and upwelling areas. Critical coastal habitats provide spawning grounds, nurseries, shelter, and food for 

finfish, shellfish, birds, and other wildlife. Coastal areas are also

sinks for pollutants transported through surface water, ground

water, and atmospheric deposition.

Coastal areas are among the most developed areas in the nation.

Coastal areas comprise 17 percent of total conterminous U.S. land

area, yet these areas are home to 53 percent of the U.S. human

population. The coastal population is increasing by about 3,600

people per day, giving rise to a projected total increase of 27 million

people between 2000 and 2015 (U.S. Census Bureau, 2002). 

Coastal areas also contribute significantly to the U.S. economy.

Almost 31 percent of the Gross National Product is produced in

coastal counties (EPA, ORD, OW, September 2001). Almost 

85 percent of commercially harvested fish depend on estuaries and

adjacent coastal waters at some stage in their life cycle (NRC, 1997).

About 180 million people use coastal beaches each year

(Cunningham and Walker, 1996). Estuaries supply water, receive discharge from municipal and industrial sources, and support agriculture, commercial and sport fisheries, and recreational uses such as

swimming, and boating. 

National estuarine and coastal monitoring programs have been in

place for 15 to 20 years. A number of agencies and programs provide information on the condition of coastal waters and wetlands,

including the National Oceanic and Atmospheric Administration’s

(NOAA) National Status and Trends Program, National Estuarine

Research Reserve System, and National Marine Fisheries Service

National Habitat Program; EPA’s National Estuary Program and

Environmental Monitoring and Assessment Program; and the Fish and

Wildlife Service National Wetlands Inventory and Coastal Program. 

In 2000, EPA, NOAA and USGS, in cooperation with all 24 U.S.

coastal states, initiated the National Coastal Assessment (also known

as Coastal 2000 or C2000). Using a compatible, probabilistic

design and a common set of survey indicators, each state conducted
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-54 5.7 What is the Ecological Condition of Coasts and Oceans? Chapter 5 - Ecological Condition

Essential Ecological Attribute

Landscape Condition

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I II

Indicators Category Source

Exhibit 5-32: Coasts and oceans indicators

Landscape Composition

Landscape Structure/Pattern

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Other Chemical Parameters

Trace Organics and Inorganics

Physical Parameters

Extent of estuaries and coastline EPA

Shoreline types DOC

Ecosystems and Communities Benthic Community Index EPA

Surface and Ground Water Flows

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

Fish diversity

Submerged aquatic vegetation

Fish abnormalities

Unusual marine mortalities

Chlorophyll concentrations

EPA

EPA

Sediment contamination of coastal waters EPA

Sediment toxicity in estuaries

Water clarity in coastal waters

EPA

EPA

EPA

Total nitrogen in coastal waters

Total phosphorous in coastal waters

EPA

EPA

Dissolved oxygen in coastal waters

Total organic carbon in sediments

EPA

EPA

DOC

Coastal living habitats DOI

Note: MAIA indicators included pending completion of peer review

Extent of Ecological System/Habitat Types

EPA
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-55

the survey and independently assessed the condition of their coastal

resources. These estimates currently are being aggregated to assess

the condition of the nation’s coastal waters. While the first complete

assessment of the nation’s coastal waters will be available in 2003, a

preliminary assessment of selected estuarine systems was published

in 2001 (EPA, ORD, OW, September 2001). 

Exhibit 5-32 lists the ecological indicators of coastal condition used

in this report. Eight indicators are discussed in Chapter 2, Purer

Water. The indicator Chlorophyll Concentrations deals with biotic

structure of phytoplankton communities, and the rest are associated

with the chemical and physical characteristics of coastal ecosystems.

These eight indicators are summarized below. The section then presents nine indicators that appear for the first time in this report. Two

involve the coastal landscape, and the rest involve the biotic structure of coastal ecosystems. There are no indicators of ecological

processes, hydrology and geomorphology, or natural disturbance

regimes with data suitable for national or regional reporting.

The following indicators presented in previous chapters relate to the

ecological condition of coasts and oceans:

Q The indicator Chlorophyll Concentrations is a measure of the

abundance of phytoplankton. Excessive growth of

phytoplankton, as measured by chlorophyll concentrations, can

lead to degraded water quality, such as noxious odors,

decreased water clarity, andoxygen depletion. Excess

phytoplankton growth is usually associated with increased

nutrient inputs (e.g., watershed or atmospheric transport,

upwelling) or a decline in filtering organisms such as clams,

mussels, or oysters (The Heinz Center, 2002).

Average seasonal ocean chlorophyll concentrations (within 25 miles

of the coast) ranged from 0.1 to 6.5 ppb (The Heinz Center,

2002). The highest ocean chlorophyll concentrations (4.8 to 6.5

ppb) were in the Gulf of Mexico with the lowest concentrations in

Hawaiian waters (0.1 ppb). Southern California had the next lowest

chlorophyll concentrations, between 1.1 and 1.5 ppb. Other ocean

waters (e.g., north, mid-, and south Atlantic, and Pacific Northwest)

had chlorophyll concentrations ranging from 2 to 4.5 ppb.

Estuarine chlorophyll concentrations were not available for

national reporting in the Heinz report, but chlorophyll

concentrations in the mid-Atlantic estuaries ranged from 0.7 to

95 ppb in 1997 and 1998 (EPA, ORD, May 2003). EPA

established three categories: good <15 ppb; fair 15-30 ppb; and

poor >30 ppb. The lower threshold of 15 ppb chlorophyll is equal

to the restoration goal recommended for the survival of

submerged aquatic vegetation (SAV) in the Chesapeake Bay

(Batiuk, et al., 2000). About 33 percent of the mid-Atlantic

estuarine area had chlorophyll concentrations exceeding 15 ppb.

The Delaware Estuary showed a wide range of chlorophyll

concentrations, from low in the Delaware Bay (<15 ppb) to

intermediate in the Delaware River (15 to 30 ppb) to very high

(>80 ppb) in the Salem River. The western tributaries to the

Chesapeake Bay were consistently high in chlorophyll, with more

than 25 percent of the area showing >30 ppb chlorophyll

concentrations. Chlorophyll concentrations in the coastal bays

were generally low (< 15 ppb), even though nutrients were

elevated, because of increased turbidity and low light penetration.

Q The Water Clarity in Coastal Waters (Chapter 2, Purer Water)

indicator is important for maintaining productive systems in good

condition and is affected by chlorophyll concentrations. Light

penetration is important for submerged aquatic vegetation (SAV),

which serves as food, nursery, shelter, and refugia habitat (areas

that provide protection from predators) for aquatic organisms.

EMAP measured water clarity using a light penetrometer, which

recorded the amount of surface light that penetrated to a depth

of 1 meter (EPA, ORD, OW, September 2001). Water clarity was

considered poor if less than 10 percent of surface radiation

penetrated to 1 meter. Water clarity was considered fair if there

was between 10 and 25 percent penetration, and clarity was

considered good if there was greater than 25 percent penetration.

Data were collected for all conterminous estuaries in the U.S. The

10 percent light penetration at 1 meter is required to support

SAV, which is an ecological endpoint in several estuarine

ecosystems. Overall, 64 percent of the nation’s estuarine area had

light penetration of at least 25 percent at 1 meter (EPA, ORD,

OW, September 2001). Only 4 percent of the nation’s estuarine

area had poor light penetration (less than 10 percent). 

Q Nitrogen, and less often phosphorus, control the chlorophyll

concentrations in coastal ecosystems. The indicator Total Nitrogen

in Coastal Waters (Chapter 2, Purer Water), was calculated for the

mid-Atlantic estuaries by summing the concentrations of total

dissolved nitrogen and particulate organic nitrogen (EPA, ORD,

May 2003). Assessment categories were determined based on the

25th and 75th percentiles because there are no total nitrogen

(TN) criteria for estuaries. The categories are: low < 0.5 ppm N;

intermediate 0.5 to 1.0 ppm N; and high > 1.0 ppm N. About

35 percent of the mid-Atlantic estuarine area had low TN

concentrations, 47 percent had intermediate TN concentrations,

and 18 percent had high TN concentrations. About 50 percent of

the mainstem area of the Chesapeake Bay had low TN

concentrations, with only about 5 percent having high TN

concentrations. The coastal bays, in contrast, had about 5 percent

of their area with low TN concentrations and about 35 percent

with high TN concentrations. The Delaware River estuary portion

of Delaware Bay had 100 percent of its area with high TN

concentrations. 

Q The indicator Total Phosphorus in Coastal Waters (Chapter 2, Purer

Water) assessment categories were based on the 25th and

75th percentile concentrations measured throughout the midAtlantic. These categories are: low < 0.05 mg P/L; intermediate

0.05 to 0.1 mg P/L; and high > 0.1 mg P/L. Total phosphorus

(TP) concentrations ranged from 0 to 0.34 mg P/L. About

58 percent of the mid-Atlantic estuarine area had low TP

concentrations, 30 percent had intermediate, and 12 percent had

high TP concentrations (EPA, ORD, May 2003). About 85 percent

of the mainstem area of the Chesapeake Bay had low TP
concentrations, with no areas having high TP concentrations. The

coastal bays, in contrast, had no areas with low TP concentrations

and about 35 percent with high TP concentrations. The Delaware

River estuary portion of Delaware Bay had 100 percent of its area

with high TP concentrations. 

Q Dissolved oxygen is depleted when phytoplankton in estuaries die

and decompose. Data on the Dissolved Oxygen in Coastal Waters

indicator (Chapter 2, Purer Water) were reported primarily for

estuaries in the Virginian, Carolinian, and Louisianian Provinces16.

Dissolved oxygen in these estuaries was reported as good because

80 percent of estuarine waters assessed were estimated to exhibit

dissolved oxygen at concentrations greater than 5 ppm (EPA,

ORD, OW, September 2001). Hypoxia resulting from

anthropogenic activities is a relatively local occurrence in Gulf of

Mexico estuaries; only 4 percent of the combined bottom areas in

these estuaries is hypoxic. The occurrence of hypoxia in the shelf

waters of the Gulf of Mexico is more significant. The Gulf of

Mexico hypoxic zone is the largest area of anthropogenic coastal

hypoxia in the western hemisphere (CAST, 1999). Since 1993,

mid-summer bottom water hypoxia in the Northern Gulf of Mexico

has been larger than 3,860 square miles and in 1999, it reached

over 7,700 square miles (CENR, 2000). 

Q Total Organic Carbon in Sediments (Chapter 2, Purer Water) is often

an indicator of organic pollution (e.g., from decomposing

phytoplankton blooms or waste disposal). Total organic carbon

(TOC) values are calculated as percent carbon in dried sediments.

Values ranged from 0.02 to 13 percent carbon (Paul, et al. 1999).

Assessment categories for the mid-Atlantic estuaries were

tentatively set at: low 1 percent; intermediate 1 to 3 percent, and

high >3 percent, but they are still under evaluation. For the midAtlantic region, about 60 percent of the sediments had low TOC

values, about 24 percent had intermediate TOC values, and

16 percent had high sediment TOC values (EPA, ORD, May

2003). Values ranged from those of Delaware Bay, with about

95 percent of its sediments having low TOC values, to those of

the Chowan River in the Albemarle-Pamlico Estuary with

65 percent of its sediments having high TOC values (EPA, ORD,

May 2003). The Chesapeake Bay mainstem had about 65 percent

of its sediments with low TOC values and about 15 percent with

high TOC values.

Q The Sediment Contamination of Coastal Waters indicator (Chapter

2, Purer Water) was analyzed in estuaries primarily along the

Atlantic Coast and Gulf of Mexico as part of the EPA EMAP

Estuaries Program. Results from these analyses indicated that

40 percent of estuarine sediments in these areas were enriched in

metals from human sources, 45 percent were enriched in PCBs,

and 75 percent were enriched in pesticides (EPA, ORD, OW,

September 2001). The highest concentrations of all three

constituents were found in South Florida sediments with

53 percent, 99 percent, and 93 percent of the sediment area

enriched in metals, PCBs, and pesticides, respectively.

Q The EPA EMAP Estuaries Program, in conjunction with the NOAA

Status and Trends Program, developed the indicator Sediment

Toxicity in Estuaries (Chapter 2, Purer Water). The EMAP Estuaries

Program found that about 10 percent of the sediments in the

Virginian, Carolinian, Louisianian, West Indian, and Californian

Province estuaries were toxic to the marine amphipod Ampelisca

abdita over a 10-day period (EPA, ORD, OW, September 2001).

The NOAA Status and Trends Program also used a sea urchin

fertility test and a microbial test to evaluate chronic toxicity in

selected estuaries. NOAA found that 43 to 62 percent of the

sediment samples from the selected estuaries showed chronic

toxicity (EPA, ORD, OW, September 2001).

On the following pages, several indicators are introduced for the first

time in this report that relate to the essential ecological attributes of

landscape condition and biotic condition of estuaries.

5-56 5.7 What is the Ecological Condition of Coasts and Oceans? Chapter 5 - Ecological Condition

EPA’s Draft Report on the Environment 2003 Q Technical Document

16 Provinces are biogeographical regions with distinct faunas.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-57

Estuarine areas provide habitat for organisms which contribute

significantly to the national economy. These areas also are under

pressure from the 53 percent of the U.S. population that lives

within 75 miles of the coast. Estuarine areas and coastline include

brackish water bays and tidal rivers, which are influenced by the

mixing of fresh water and ocean salt water in these areas. Extent

estimates were provided by the coastal states as part of the EPA

National Water Quality Inventory - 2000 Report (EPA, OW,

August 2000).

What the Data Show

EPA estimates that the U.S. and its territories have 95.9 million

acres of estuarine surface area and about 58,618 miles of coastline (EPA, OW, August 2002).

Indicator Gaps and Limitations

These data were compiled from inventories performed by the

states. Differences in how each state defines estuaries are likely, so

the consistency of the inventory is unknown.

Data Source

The data source for this indicator was the 2000 National Water

Quality Inventory, U.S. Environmental Protection Agency, August

2002. (See Appendix B, page B-45, for more information.)

Indicator Extent of estuaries and coastline – Category 1 

This indicator provides the acreage of vegetative habitat such as

submerged aquatic vegetation (SAV), mangrove forests, and

coastal wetlands. Vegetation not only stabilizes the habitat, but

also provides food, shelter, nursery areas, and refugia for other

aquatic organisms. Loss of coastal habitat is a major contributor

to the loss of both economic and non-marketable aquatic species

(The Heinz Center, 2002).

What the Data Show

The USFWS National Wetlands Inventory (NWI) estimates

more than 5 million acres of coastal wetlands contribute to

the diversity of coastal habitat (Exhibit 5-33). Wetland

acreage declined about 8 percent from the mid-1950s to

the mid-1990s (The Heinz Center, 2002). Out of 5 million

total acres, 400,000 acres of coastal wetland were lost over

this period, although the loss rate declined in the 1990s 

(The Heinz Center, 2002).

Indicator Gaps and Limitations

Data for coral reefs and seagrasses and other SAV are available for many areas, but these data have not been integrated to produce a national estimate. Different approaches

have been used to estimate some of these coastal habitats

which make make integration difficult. For example, estimates of the extent of SAV are noted in some regions only

as presence/absence, while the area is estimated quantitatively in other regions. Data for vegetated wetlands are

available for only the East and Gulf Coasts.

Data Source

The data source for this indicator was Status and Trends of

Wetlands in the Conterminous United States 1986 to 1997, Dahl,

2000, utilizing data from the National Wetlands Inventory. 

(See Appendix B, page B-45, for more information.)

Indicator Coastal living habitats – Category 2 

0

1

2

3

4

5

6

1950 1960 1970 1980 1990 2000

millions of acres

Coverage: Atlantic and Gulf Coasts Only

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from the U.S. Fish and Wildlife Service. 

Partial Indicator Data: Coastal Vegetated Wetlands

Exhibit 5-33: Coastal living habitats, 1950s-1990s

Data Not Adequate for National Reporting on:

■ Seagrasses/Submerged Vegetation

■ Shellfish Beds

■ Coral Reefs

■ Wetlands in Other Regions
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-58 5.7 What is the Ecological Condition of Coasts and Oceans? Chapter 5 - Ecological Condition

This indicator includes the miles of coastline in different categories,

such as beaches, mud or sand flats, rock or clay cliffs, and wetlands.

It also includes coastline that is protected with engineered structures

such as armoring or riprap. Loss or conversion of shoreline habitat to

armoring or riprap can eliminate the habitat required by various

organisms for spawning, gestation, nursery area, feeding, or refugia. 

What the Data Show

Over two-thirds of the mapped shoreline in the south Atlantic,

southern California, and Pacific Northwest is coastal wetlands,

with most of the coastal wetlands occurring in the South Atlantic

(The Heinz Center, 2002) (Exhibit 5-34). Three-quarters of the

south Atlantic shoreline is wetlands (The Heinz Center, 2002).

Beaches account for about 33 percent of the shoreline in both

southern California and the Pacific Northwest. Southern

California, however, has a much lower percentage of wetlands and

mud or sand flats than the Pacific Northwest. Steep shorelines,

mud flats, and sand flats each make up the smallest portion of the

total in all three regions. Armored shorelines, which inclde bulkheads and rip rap, account for about 11 percent of miles of the

total coastline.

Indicator Gaps and Limitations

Estimates of shoreline types are not available for the entire U.S.,

including much of the Atlantic and Gulf Coast areas. Some of the

atlases used to compile this information are more than 15 years

old. Coastal areas are dynamic and change over time, so the accuracy of available estimates is unknown.

Data Source

The data source for this indicator was the Environmental

Sensitivity Index Atlases, National Oceanic and Atmospheric

Administration (1984-2001). (See Appendix B, page B-46, for

more information.)

Indicator Shoreline types – Category 2

Partial Indicator Data: Shoreline Types by Region 

0 20 40 60 80 100

South Atlantic

Percent of Total Regional Shoreline

Pacific

Northwest

Southern

California

Coverage: Pacific Northwest, Southern California, and South Atlantic Regions only 

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the National Oceanic and Atmospheric Administration. 

Exhibit 5-34: Coastal shoreline types, 2000

Steep Sand, 

Rock, Clay

Mud or Sand 

Flats

Beaches

Wetlands,

mangroves, etc.

Armored

(bulkheads

or riprap)

Data Not Adequate for National Reporting on:

Q North Atlantic

Q Mid-Atlantic

Q Gulf of Mexico

Q Gulf of Alaska

Q Bering Sea

Q Hawaii
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-59

EMAP Estuaries Program has developed indices of benthic condition for estuaries in the conterminous U.S. (Engle and Summers,

1999; Engle, et al., 1994; Van Dolah, et al., 1999; Weisberg, et al.,

1997). Benthic macroinvertebrates include annelids, mollusks, and

crustaceans that inhabit the bottom substrates of estuaries. These

organisms play a vital role in maintaining sediment and water quality, and are an important food source for bottom-feeding fish,

invertebrates, ducks, and marsh birds. Measures of biodiversity

and species richness, species composition, and relative abundance

or productivity of functional groups are among the assemblage

attributes that can be used to characterize benthic community

composition and abundance. The Heinz report refers to this indicator as Condition of Bottom-Dwelling Organisms (The Heinz

Center, 2002).

Assemblages of benthic organisms are sensitive to pollutant exposure (Holland, et al., 1987, 1988; Rhoads, et al., 1978; Pearson

and Rosenberg, 1978; Sanders, et al., 1980; Boesch and

Rosenberg, 1981), and they integrate responses to disturbance

and exposure over relatively long periods of time (months to

years). Their sensitivity to pollutant stress is, in part, because

they live in sediment that accumulates environmental contaminants over time (Nixon, et al., 1986), and because they are relatively immobile. 

Reference sites were used to calibrate the indices similar to the

approach used to calibrate fish IBI scores in fresh water ecosystems. The references cited above describe the approaches used

for calibration and scoring in various estuarine provinces. These

indices were calibrated for the respective estuarine province in

which they were developed. While the development and calibration process was similar among provinces, the specific thresholds

reflect the estuarine conditions within that province. In general,

good condition means that less than 10 percent of the coastal

waters have low benthic index scores. Fair condition means that

between 10 and 20 percent of the coastal waters have low benthic

index scores. Poor condition means that greater than 20 percent

of the coastal waters have low benthic index scores.

What the Data Show

Benthic community index scores have been assessed for the

Northeast, Southeast, and Gulf Coastal Areas. For the Northeast,

Southeast, and Gulf Coastal areas, 56 percent of the coastal

waters were assessed in good condition, 22 percent in fair condition, and 22 percent in poor condition based on benthic index

scores (Exhibit 5-35). 

Associations of biological condition with specific stressors indicate that, of the 22 percent of coastal areas with poor benthic

condition, 62 percent had sediment contamination, 11 percent

had low dissolved oxygen concentrations, 7 percent had low light

penetration, and 2 percent showed sediment toxicity (EPA, ORD,

OW, September 2001).

Indicator Gaps and Limitations

Benthic community index scores have been assessed only for the

Northeast, Southeast, and Gulf Coastal areas. Samples have been

collected in all coastal areas, including Alaska, Hawaii, and Island

Territories, but these data have not been assessed. A complete

assessment of coastal condition is anticipated in 2003.

Data Source

The data source for this indicator was National Coastal Condition

Report, U.S. Environmental Protection Agency, September 2001,

using data from the Environmental Monitoring and Assessment

Program, Estuaries Program. (See Appendix B, page B-46, for

more information.)

Indicator Benthic Community Index – Category 2

Exhibit 5-35: Benthic Community Index (BCI) 

scores for coastal waters in good, fair, 

or poor condition, 2000

22%

Fair

56%

Good

22% Poor 2% Poor

18% No Sediment

or Water Contamination

11% Low 

Dissolved

Oxygen 

Concentrations

7% Light 

Penetration

2% 

Sediment 

Toxicity

62% Sediment

Contamination

Coverage: Northeast, Southeast, and Gulf Coastal areas 

Source: EPA, Office of Research and Development and Office of Water. 

National Coastal Condition Report. September 2001.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-60 5.7 What is the Ecological Condition of Coasts and Oceans? Chapter 5 - Ecological Condition

Fish diversity is considered to be an indicator of ecological condition because fish integrate effects of environmental stress over

space and time (EPA, ORD, September 1998). For this indicator,

fish collected by trawling are identified, enumerated, and measured, allowing assessment of native and non-native species, diversity, abundance, pollution-tolerant/intolerant, and size class 

(e.g., young-of-year and adults).

This indicator provides data for the mid-Atlantic estuaries.

Because fish catch data are sensitive to different sampling gear, no

critical thresholds were established for the mid-Atlantic estuaries.

High and low diversity were arbitrarily established as: high > 3 fish

species in a standard trawl; low < 3 fish species in

a standard trawl (EPA, ORD, May 2003). 

What the Data Show

In 1998, out of 110 sampling sites selected for

the mid-Atlantic estuaries in 1998, fish trawls

were conducted at 80 sites (the others were too

shallow to trawl). The fish species count ranged

from 0 to 13, with an average of 4.6 species per

site (Exhibit 5-36). For the mid-Atlantic estuaries

in general, more fish species were found in upper

Delaware Bay, the coastal bays, and in the upper

portions of tributaries. Fewer species were evident in the Chesapeake Bay mainstem and lower

tributaries.

Indicator Gaps and

Limitations

The limitations of this indicator include the following:

Q Fish diversity estimates are available only for

the mid-Atlantic estuaries. 

Q While fish diversity can be determined for each

sampling site, currently no context exists for

interpreting the condition of estuaries from

fish diversity numbers because there are no

criteria or thresholds for relating fish diversity

estimates to estuarine condition. 

Q Fish populations are highly mobile, so caution

must be used in interpreting low diversity

estimates for measurements observed at any

individual site may not be representative of the

condition of the estuary.

Data Source

The data source for this indicator was the Mid-Atlantic Integrated

Assessment, MAIA-Estuaries, 1997-1998 Summary Report,

U.S. Environmental Protection Agency, May 2003. 

(See Appendix B, page B-46, for more information.)

Indicator Fish diversity – Category 2

Exhibit 5-36: Fish diversity in mid-Atlantic bays, 1997-1998 

Coverage: Mid-Atlantic bays (Delaware, Maryland, New Jersey, Virginia).

Source: EPA, Office of Research and Development, Atlantic Ecology Division. Mid-Atlantic Integrated Assessment, MAIA - 

Estuaries 1997-98, Summary Report. May 2003.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-61

Many estuarine systems contain submerged aquatic vegetation

(SAV), which provides habitat and refugia for fish and invertebrates,

helps protect shorelines from erosion, contributes to sediment

accretion, and provides food for aquatic organisms. The vegetation

also stabilizes shifting sediments and adds oxygen to the water. SAV

is sensitive to pollution and shading by turbid water.

In the mid-Atlantic region, Mid-Atlantic Integrated Assessment

(MAIA) field crews noted the presence or absence of SAV at their

sampling stations as an ancillary measurement, but no attempt

was made to estimate the extent of SAV. For the Chesapeake Bay,

however, SAV extent is an ecological endpoint, and restoration of

SAV is one of the goals of the Chesapeake Bay Program (Batiuk,

et al., 2000). 

What the Data Show

Scientists estimated that historically there were about 600,000

acres of SAV in the Chesapeake Bay. A 1978 aerial survey estimated

that this SAV acreage had decreased to 41,000 acres, but total

acreage had increased to over 69,000 acres by 2000 (Moore, et

al., 2000). Extent measures are not currently available for the rest

of the nation’s estuarine systems.

Indicator Gaps and Limitations

The limitations of this indicator include the following:

Q SAV estimates have been analyzed and reported only for the

mid-Atlantic estuaries but not for the entire U.S. 

Q These SAV estimates are for presence/absence only and do not

indicate the density or abundance of the vegetation. More

quantitative approaches using remote sensing are being used,

but this information is not currently available for the entire U.S.

coastline.

Data Source

The data sources for these indicators were Chesapeake Bay

Submerged Aquatic Vegetation Water Quality and Habitat-Based

Requirements and Restoration Targets: A Second Technical

Synthesis, U.S. Environmental Protection Agency, Chesapeake Bay

Program, 2000; and Mid-Atlantic Integrated Assessment, MAIAEstuaries, 1997-1998 Summary Report, U.S. Environmental

Protection Agency, May 2003. (See Appendix B, page B-47, for

more information.)

Indicator Submerged aquatic vegetation – Category 2

External abnormalities in fish can include lumps, growths, ulcers,

fin rot, gill erosion, and gill discoloration. The cause of an abnormality is not always chemical contamination—it could also result

from an injury or disease. A high incidence of such conditions

could, however, indicate an environmental problem. 

What the Data Show

The EPA EMAP Estuaries Program examined more than 100,000

fish from estuaries in the Virginian, Carolinian, Lousianian, and

West Indian Province estuaries for evidence of disease, parasites,

tumors and lesions on the skin, malformations of the eyes, gill

abnormalities, and skeletal curvatures. Of all the fish examined,

only 0.5 percent (454 fish) had external abnormalities (EPA,

ORD, OW, September 2001). Of the fish examined, bottom-feeding fish had the highest incidence of disease, but this incidence

was still low. There is no criterion for what constitutes a high or

low number of fish abnormalities.

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q Fish abnormality estimates are not available nationally for U.S.

estuaries. 

Q Fish abnormalities can result from both natural causes such as

injury and from chemical contamination, and the cause cannot

be readily assessed. 

Data Source

The data source for this indicator was National Coastal Condition

Report, U.S. Environmental Protection Agency, September 2001,

using data from the Environmental Monitoring and Assessment

Program, Estuaries Program. (See Appendix B, page B-47, for more

information.)

Indicator Fish abnormalities – Category 2
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-62 5.7 What is the Ecological Condition of Coasts and Oceans? Chapter 5 - Ecological Condition

Unusual marine mortalities are characterized by an abnormal number of dead animals in locations or at times of the year that are

not typical for that species. For animals such as turtles, whales,

dolphins, seals, sea lions, or similar vertebrates, where small numbers of deaths can be significant, this indicator reports the actual

number of dead animals. For other more abundant animals such as

fish, sea birds, and shellfish, the number of mortality events is

recorded. The cause of these unusual events might include infectious disease, toxic algae, pollutants, or natural events.

What the Data Show

More than 2,500 California sea lions were involved in unusual

marine mortalities in 1992, which is more than 10 times the number of seals, sea lions, sea otters, or manatees lost in similar

events since 1992 (The Heinz Center, 2002) (Exhibit 5-37). The

next two largest events were the deaths of 150 manatees off the

Florida coast in 1996 and the deaths of 185 California sea lions in

1997 (The Heinz Center, 2002). No causes for these events were

cited in the Heinz report (The Heinz Center, 2002).

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q This indicator represents only unusual events; it does not

represent all observed mortalities of marine organisms. 

Q Criteria or thresholds do not exist for assessing the importance

of unusual mortalities. 

Q It is not possible to determine if the event was caused by

natural phenomena such as El Nino or was the result of

anthropogenic influences. 

Q The data are not available on a national basis.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from the U.S.

Department of Commerce, National Oceanic and Atmospheric

Administration, National Marine Fisheries, Office of Protected

Resources, Marine Mammal Health, Stranding Response Program,

CRC Handbook of Marine Mammal Medicine: Health, Disease, and

Rehabilitation, 2nd edition (Dierauf and Gulland, eds., 2001). 

(See Appendix B, page B-47, for more information.)

Indicator Unusual marine mortalities – Category 2 Number of Mortalities

Whales, 

Dolphins and 

Porpoises

Seals, Sea 

Lions, Sea 

Otters and

Manatees

Coverage: all U.S. waters.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002. 

Data from the National Marine Fisheries Service and Dierauf and Gulland (2001). 

0

200

400

600

2500

Exhibit 5-37: Unusual marine mortalities, 1992-2001

Partial Indicator Data: Marine Mammals

Data Not Adequate for National Reporting on Sea Turtles

1990 1995 2000 2005
Technical Document Q EPA’s Draft Report on the Environment 2003

Summary: The Ecological Condition of Coasts and

Oceans

Coasts and oceans are subject to the same pressures as fresh waters,

especially because they represent the endpoint for most fresh water

drainage networks. Problems are exacerbated by the hydrology of

estuaries, which tends to create conditions ideal for concentration of

pollutants entering from upstream.

Landscape condition

The extent of this resource has been described by EPA and NOAA,

and the landscape composition of much of the nation’s coastline is

known, providing a baseline against which to monitor future changes.

As an example, 400,000 of 5,000,000 acres of coastal wetland

were lost since the mid-1950s, although the loss rate declined in the

1990s (The Heinz Center, 2002). The baseline information is inadequate, however, for coral reefs, shellfish beds, and SAV, although a

survey in Chesapeake Bay indicates that the acreage of SAV there

increased from 41,000 to 69,000 acres since 1978 (Moore, et al.,

2000). The estuarine landscape structure and pattern, and their

contribution to ecological condition, remain inadequately measured

or understood.

Biotic condition

The National Coastal Assessment, a joint federal and state 

interagency national monitoring program implemented to assess

the ecological condition of the nation’s estuaries, has developed

regional data on several biotic condition indicators, including fish,

benthic communities, and SAV. The program is also monitoring

abnormalities and tissue contaminants. Results from three regions

(Northeast, Southeast, and Gulf) indicate that, on average, 

44 percent of the bottom community was in fair or poor condition,

but this number varies among regions. Chlorophyll concentrations,

which reflect the amount of phytoplankton growing in the water

column, were over the recommended limit of 15 ppm (to protect

SAV beds) over one-third of the estuarine area in the mid-Atlantic

states. No similar estimates are yet available nationwide. Of more

than 100,000 fish in random trawls from Maine to Texas, less than

0.5 percent showed visible evidence of disease, parasites, tumors

or lesions of the skin, malformation of the eyes or gills, or skeletal

curvature. Fish tissue contamination (other than non-toxic arsenic)

was found in about 4 percent of fish.

Chemical and physical characteristics

A number of physical and chemical indicators are being monitored in

estuarine systems to help diagnose and interpret biotic condition

information. Data are available only for estuaries on the Atlantic or

Gulf coasts, but 18 percent of mid-Atlantic estuaries were judged to

have high nitrogen concentrations (which can lead to harmful algal

blooms), and 12 percent had high concentrations of phosphorus.

Twenty percent of Atlantic and Gulf estuaries had low dissolved oxygen concentrations (<5 ppm). On average, 75 percent of the sediments had elevated pesticide concentrations, and 40 percent had

elevated concentrations of heavy metals, again with significant variation from region to region. Ten percent of the sediments showed a

positive response to toxicity tests using a marine amphipod. Only 

4 percent of the estuaries had poor light penetration. 

There were no Category 1 or 2 indicators of ecological processes,

hydrology and geomorphology, or natural disturbance regimes available

for this report. The dearth of indicators for ecological processes is

likely due, in part, to the fact that these indicators typically require

repeated visits over several days, which makes systematic sampling in

estuaries time-consuming and expensive. Procedures using remote

sensing to assess ecological processes are being developed, but

these are not ready for national or regional implementation.

Hydrologic indicators may be similar to those for fresh water 

systems, but are complicated by the complex flows caused by tides

and other phenomena in estuaries. An indicator of sea level change

also may be useful. Storms, hurricanes, and similar disturbances are

monitored globally, nationally, regionally, and locally, but this 

information has not been developed in the form of an indicator.

Information on disturbance regimes could also be used to partition

observed estuarine system responses into portions attributable to

natural versus anthropogenic disturbances.

Chapter 5 - Ecological Condition 5.7 What is the Ecological Condition of Coasts and Oceans? 5-63
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-64 5.8 What Is the Ecological Condition of the Entire Nation? Chapter 5 - Ecological Condition

5.8 What Is the

Ecological Condition of

the Entire Nation?

The previous sections asked questions about the ecological condition of forests, coasts and oceans, fresh water ecosystems, urban

and suburban areas, farmlands, and grasslands and shrublands

nationally. Because ecosystems are hierarchical (O’Neill, et al., 1986)

some important questions about ecological condition cannot be

answered in terms of these land cover classes. Examples of largescale issues include the following:

Q The relative distribution of

forests, grasslands, farmlands,

and urban/suburban areas

across the entire nation.

Q Neotropical migratory birds and

other species do not depend on

one ecosystem type, but many,

often spread over large regions. 

Q The condition of forest streams,

and of other low-order streams

across regions, was considered in

Section 5.6, but processes in

very large watersheds (e.g., the

Mississippi or Columbia River

basins) reflect the sum total of

contributions from many

ecosystem types. 

Q Typically, large systems are

slower to change and to respond

to management actions (O’Neill,

et al., 1986; Messer, 1992).

Global climate change and

changes in stratospheric ozone

are examples of stressors of this

type (Rosswall, et al., 1988). 

Because EPA’s regulatory programs, both alone and in combination,

typically impact many kinds of ecosystems, such large-scale questions are an important part of tracking the overall effectiveness of

these programs in protecting the entire nation.

Exhibit 5-38 shows the indicators for the entire nation used in this

report. All seven of the indicators are taken from the core national

indicators in The State of the Nation’s Ecosystems (The Heinz Center,

2002). There are indicators for four of the six essential ecological

attributes with at least regional data, but no indicators on hydrology

and geomorphology or natural disturbance regimes with data available on a national or regional level (The Heinz Center, 2002).

Essential Ecological Attribute

Landscape Condition

Biotic Condition

Ecological Processes

Chemical and Physical Characteristics

Hydrology and Geomorphology

Natural Disturbance Regimes

I 2

Indicators Category Source

Exhibit 5-38: Indicators covering the entire nation

Extent 

Landscape Composition

Landscape Pattern/Structure

Species and Populations

Organism Condition

Energy Flow

Material Flow

Nutrient Concentrations

Other Chemical Parameters

Trace Organic and Inorganic Chemicals

Ecosystem extent

At-risk native species

Bird Community Index

Movement of nitrogen

Terrestrial Plant Growth Index

Chemical contamination

USDA, DOI, DOC

NatureServe

EPA

DOI

DOI, DOC

Ecosystems and Communities

Surface and Ground Water Flows

Physical Parameters

Dynamic Structural Conditions

Sediment and Material Transport

Frequency

Extent

Duration

DOI, EPA
Technical Document Q EPA’s Draft Report on the Environment 2003

Extent provides basic information on how much of an ecosystem

exists, where it is, and whether it is changing over time. Changes in

the extent of various cover types in the U.S. have been driven primarily by human land and water uses over the past 400 years. The total

amount and relative distribution of land-cover types at the regional

and national level are important, because ultimately they affect many

of the ecological attributes such as biodiversity. For example, not only

do forest species depend on forests, but many forest species also

depend on adjacent wetlands or grasslands.

What the Data Show

Estimates show that before European settlement, the U.S. had 1

billion acres of forests (USDA, FS, 2002), 900 to 1,000 million

acres of grasslands and shrublands (Klopatek, et al., 1979) and

221 million acres of wetlands (Dahl, 2000). Today, the U.S. has

749 million acres of forests (USDA, FS, 2002), 861 million acres

of grasslands and shrublands (The Heinz Center, 2002), and 106

million acres of wetlands (Dahl, 2000). About 530 million acres

of croplands (USDA, NRCS, 2000) and 90 million acres of urban

and suburban land uses (USDA, NRCS, 2001) have been added.

The acreage of forest and fresh water wetlands have each declined

by about 10 million acres in the decades since the 1950s; the

acreage of croplands has fluctuated, but it is currently about 35

million acres less than in the 1950s; and urban areas have grown

by 40 million acres during the same period (The Heinz Center,

2002) (Exhibit 5-39).

Indicator Gaps and Limitations

According to The Heinz Center (2002), the National Land Cover

Database (NLCD) produced different estimates of area for forests

and farmlands from those mentioned above, because of differences in the definitions of these systems in the Forest Inventory

and Analysis (FIA) and the USDA Economic Research Service

(ERS). In addition, current indicators of extent do not provide

information about fragmentation and landscape patterns.

Data Sources

The data sources for these indicators were Forest Inventory and

Analysis, U.S. Department of Agriculture (1979-1995); National

Land Cover Database, Multi-Resolution Land Characteristics

Consortium (1990s); National Wetlands Inventory, U.S. Fish and

Wildlife Service (1970-2000); and Economic Research Service,

U.S. Department of Agriculture (1982-1997). (See Appendix B,

page B-48, for more information.)

Indicator Ecosystem extent – Category 2

Chapter 5 - Ecological Condition 5.8 What Is the Ecological Condition of the Entire Nation? 5-65 Percent of U.S. Land Area (lower 48 states)

Partial Indicator Data: Long-term Changes for For Forests, Croplands, 

Grasslands/Shrublands, Urban/Suburban

Exhibit 5-39: Change in ecosystem extent, long-term and 

recent trends, 1950s-1990s

0

20

40

60

80

100

Presettlement 1990s

Percent of U.S. Land Area (lower 48 states)

Partial Indicator Data: Recent Trends for Forests, Croplands, Grasslands/Shrublands, 

Urban/Suburban, Freshwater Wetlands 

0

10

20

30

40

50

1950 1960 2000 1970 1980 1990

Grassland/

Shrublands

(satellite)

Forests

Forests

(satellite)

Croplands

(satellite)

Croplands

Freshwater

W etlands

Urban

Urban/

Suburban

(satellite)

Grasslands and 

Shrublands

Forests

Croplands

Urban and 

Suburban

Data Not Adequate for National Reporting on Extent of 

brackish coastal waters

Coverage: lower 48 states.

Note: Because these estimates are from different sources, they do not sum to 100% 

of U.S. land area. Approximately 5% of lands are not accounted for by these data 

sources. They include some wetlands, some non-suburban developed areas, disturbed 

areas such as mines and quarries and the like. In addition, freshwater wetlands 

currently occupy approximately 5% of the area of the lower 48 states, a reduction of 

about 50% since presettlement times. Because they are found within forests, 

grasslands, and shrublands, or croplands, freshwater wetlands from those ecosystems 

are shown as aggregated data on the graph. Finally, the "urban" trend line in this 

graph is based on a different definition from the one in this report and is presented 

here to illustrate general trends. The definition used in this report was used to 

generate the "urban/suburban (satellite)" area estimate. 

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from the USDA Forest Service (forests, current area, recent trends), USDA 

Economic Research Service (croplands trends, urban area trends), Multi-Resolution 

Land Characterization Consortium (MRLC; all satelite data, including current estimate 

of grass/shrub and urban/suburban area in top graph). Presettlement estimates are 

from Klopatek et al. 1979. 
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-66 5.8 What Is the Ecological Condition of the Entire Nation? Chapter 5 - Ecological Condition

Scientists are engaged in considerable discussion about the

importance of rare and at-risk species for the sustainability of

ecosystems (e.g., Grime, 1997; Hodgson, et al., 1998; Naeem, et

al., 1999; Tilman and Downing, 1994; Wardle, et al., 2000). There

are at least 200,000 native plant, animal, and microbial species in

the U.S., but according to The Heinz Center (2002), “little is

known about the status and distribution of most of these.” This

indicator represents what is known about 22 species groups,

including 16,000 plant species and 6,000 animal species. It

includes all higher plants; all terrestrial and fresh water vertebrates

(i.e., mammals, birds, reptiles, amphibians, and fish); select invertebrate groups, including fresh water mussels and snails, crayfishes,

butterflies and skippers; and about 2,000 species of grasshoppers, moths, beetles, and other invertebrates (The Heinz Center,

2002). The Heinz Center believes that this indicator is a powerful—yet manageable—snapshot of the condition of U.S. species.

No data are available for marine species, which led The Heinz

Center to rank this as an indicator equivalent to a

Category 2. Special groupings of these species have

been used as indicators in specific ecosystem categories. This indicator includes all of them, but The

Heinz Center has not analyzed species dependent on

large or multiple ecosystems.

What the Data Show

One-third of species native species are at risk, and

1 percent of plant and 3 percent of animal species

might already be extinct (The Heinz Center, 2002)

(Exhibit 5-40). Approximately 19 percent of native

animal species and 15 percent of native plant species

are ranked as imperiled or critically imperiled. There

are large differences among plant and animal groups

and among regions. For example, the percentage of atrisk fresh water species such as mussels and crayfish is

much higher than that for birds or mammals, and more

at-risk species are found in California, Hawaii, the

southern Appalachians, and Florida than elsewhere

(Stein, 2002).

Indicator Gaps and Limitations

The data are from a census approach that focuses on the location

and distribution of at-risk species. Therefore, distinguishing trends in

the indicator is difficult.

Data Source

The data for this indicator was The State of the Nation’s Ecosystems,

The Heinz Center, 2002, using data from the NatureServe Explorer

database. (See Appendix B, page B-48, for more information.)

Indicator At-risk native species – Category 2

Exhibit 5-40: At-risk land and fresh water 

plant and animal native species, 2000

Percent of all species

0

5

10

15

20

25

30

35

Land and Fresh water Plants Land and Fresh water Animals

Coverage: all 50 states.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from NatureServe and its Natural Heritage member programs.

Extinct

Critically Imperiled

Imperiled

Vulnerable

All At-Risk
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.8 What Is the Ecological Condition of the Entire Nation? 5-67

Indicator Bird Community Index - Category 2

The types of birds observed in an area have been shown to serve as

an indicator of the overall characteristics of the landscape. Species

vary in their sensitivity to physical, chemical, and biological threats,

and different species require different habitats for food, shelter, and

reproduction. Some species need extensive areas of interior forest,

others prefer the edges between different types of land cover or

mixed areas, and still others prefer disturbed or highly managed

areas. Consequently, the composition of the bird community reflects

the overall mix, pattern, and condition of the mosaic of forest, agriculture, grasslands and shrublands, wetlands, streams, and

urban/suburban areas that makes up most of the U.S. landscape.

The Bird Community Index (BCI) was developed by O’Connell, et al.

(1998, 2000) for songbirds in the mid-Atlantic states. The index

was developed based on data collected at 34 reference sites, with

bird species classified into 16 functional groups according to the

degree to which they specialized in using the native flora and fauna

in an area (high BCI scores) versus being generalists and exotic or

invasive species (low BCI scores). The BCI then was applied to a

probability sample of bird data from 126 sites across the MidAtlantic Highlands. 

Land Cover Types of Birds

= 87% Forest Cover

= 80 ft. Height

= 61% Canopy Closure

= 87% Forest Cover

= 65 ft. Height

= 47% Canopy Closure

Mature Forest Forest Mixed Rural Urban

>61% Non-Woody 

Plant/Agriculture

>29% Residential/ 

Commercial

Excellent Good Fair Poor Rural Poor Urban

16% 27% 36% 16% 5%

Scarlet Tanager, American Redstart, Black-and-White Warbler, Black-Throated Green Warbler, Hairy Woodpecker,

Ovenbird, Cerulean Warbler, Worm-Eating Warbler...

American Goldfinch, Brown Thrasher, Common Yellowthroat, Gray Catbird, Red-Winged Blackbird, Yellow Warbler, Indigo Bunting...

House Sparrow, House Finch, Rock Dove (Pigeon), European Starling

Interior Forest Dwellers

Shrub Nesters

Exotics

Ecological Conditions

Exhibit 5-41: Bird species as characteristics of landscape composition and pattern as an indicator of 

landscape condition, 1995-1996

Coverage: Mid-Atlantic Highlands (Maryland, Pennsylvania, Virginia, West Virginia).

Source : EPA, Office of Research and Development. Birds Indicate Ecological Condition of the Mid-Atlantic Highlands. June 2000.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-68 5.8 What Is the Ecological Condition of the Entire Nation? Chapter 5 - Ecological Condition

Indicator Bird Community Index - Category 2 (continued)

What the Data Show

Good-to-excellent BCI scores (diverse communities of birds characterized by many specialists and native species) were associated with

at least 87 percent forest cover and a minimum of 47 percent

canopy closure. Poor BCI scores (low diversity communities characterized by generalists and exotic species) were associated with

either rural agricultural or urban areas where almost 30 percent of

the landscape was in residential or commercial land use.

The BCI was calibrated across a range of landscape conditions

from least disturbed to significantly degraded. Based on this 

calibration, 43 percent of the Mid-Atlantic Highlands was estimated to be in good to “excellent” condition (in other words, containing large tracts of interior forest), 36 percent was estimated to

be in “fair” condition, and 21 percent (5 percent urban and 16

percent rural) was estimated to be in “poor” condition (Exhibit 5-

41). Forested sites in good and excellent condition supported different bird communities and ground-level vegetation attributes,

but could not be separated by land cover composition alone. As

the proportion of the landscape in forested areas decreased or

the proportion of canopy closure decreased, so did the BCI

scores (O’Connell, et al., 1998, 2000).

Indicator Gaps and Limitations

The limitations of this indicator include the following:

Q This indicator depends on a value judgement common among

ecologists that communities associated with the native

vegetation of a region are “better” than exotic, generalist

species associated with human modification of the environment. 

Q The BCI has been calibrated and assessed only for the MidAtlantic Highlands, and may not apply to areas where shoreline

birds or migratory waterfowl are a larger component of the bird

community.

Q The BCI relates primarily to land cover estimates, and does not

explicitly include the condition of any particular land cover type. 

Data Source

The data sources for this indicator were A Bird Community Index of

Biotic Integrity for the Mid-Atlantic Highlands, O’Connell, et al.,

1998; and Bird Guilds as Indicators of Ecological Condition in the

Central Applachians, O’Connell, et al., 2000, using data from U.S.

Environmental Protection Agency Mid-Atlantic Highlands Program

and the National Land Cover Database. (See Appendix B, 

page B-48, for more information.)
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.8 What Is the Ecological Condition of the Entire Nation? 5-69

Both the National Research Council and Science Advisory Board

reports suggest that primary productivity (the amount of solar

energy captured by plants through photosynthesis) is a key 

indicator of ecosystem function (NRC, 2000; SAB, 2002).

Generally, ecosystems will maximize their primary productivity

through adaptation (Odum, 1971), so primary productivity can

increase under favorable conditions (e.g., increased nutrients or

rainfall) or decrease under unfavorable conditions (e.g., plant stress

caused by toxic substances or disease). Changes in primary productivity can result in changes in the way ecosystems function, in the

yield of crops or timber, or in the animal species that live in the

ecosystems.

Gross primary productivity is related to the standing crop of the

photosynthetic pigment chlorophyll and can be thought of in 

simple terms as plant growth. The Terrestrial Plant Growth Index

indicator is based on the Normalized Difference Vegetation Index

(NDVI), which measures the amount of chlorophyll, using satellite

data (The Heinz Center, 2002). While the standing crop of

chlorophyll is not identical to primary productivity, EPAs Science

Advisory Board (EPA, SAB, 2002) lists it as an example of an

indicator under the ecological processes EEA.

What the Data Show

No overall trend in plant growth is observed for the 11-year period

from 1989 through 2000, for any land cover type or any region of

the U.S., although year-to-year measurements can fluctuate by up

to 40 percent of the 11-year average (The Heinz Center, 2002)

(Exhibit 5-42). Over a sufficiently long period, regional trends in

NDVI could be an important indicator of increasing or decreasing

plant growth resulting from changing climate, UV-B exposure, air

pollution, or other stressors. 

Indicator Gaps and Limitations

There were no calculations for phytoplankton or submerged 

vegetation growth in fresh water or coastal systems.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data on visible and

near-infrared wavelengths collected by the National Oceanic and

Atmospheric Administration’s Advanced Very High Resolution

Radiometer and converted into a Normalized Difference

Vegetation Index (Reed and Young, 1997). (See Appendix B, page

B-49, for more information.)

Indicator Terrestrial Plant Growth Index – Category 1

Plant Growth Index

Forests

Grasslands/

Shrublands

Croplands

All Three 

Systems

0.6

0.8

1.0

1.2

1.4

1.6

1988 1992 1996 2000

Exhibit 5-42: Plant Growth Index, 1989-2000 

Terrestrial Plant Growth Index for lower 48 states

Plant Growth Index

Southwest

Rocky 

Mountain

Pacific

U.S. (lower 48)

Plant Growth Index

Coverage: Lower 48 states. 

Note: Because of satellite problems, no data are available for 1994. 

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from the U.S. Geological Survey; Multi-Resolution Land Characterization Consortium. 

Northeast/

Mid-Atlantic

Southeast

Midwest

U.S. (lower 48)

0.6

0.8

1.0

1.2

1.4

1.6

1988 1992 1996 2000

0.6

0.8

1.0

1.2

1.4

1.6

Plant Growth Index: southwest, rocky mountain, pacific regions 

Plant Growth Index: northeast, southeast, midwest regions
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-70 5.8 What Is the Ecological Condition of the Entire Nation? Chapter 5 - Ecological Condition

Indicator Movement of nitrogen – Category 1

Nitrogen is a critical nutrient for plants, and “leakage” of nitrogen

from watersheds can signal a decline in ecosystem function

(Vitousek, et al., 2002). It also may signal the failure of watershed

management efforts to control point, non-point, and atmospheric

sources of nitrogen pollutants, and the resulting nitrogen may

have “cascading” harmful effects as it moves downstream to

coastal ecosystems (Galloway and Cowling, 2002). Nitrate 

concentration in streams has served as an indicator of chemical

condition in the other ecosystems in this section. This indicator,

however, deals with nitrogen export from large watersheds, and is

an indicator of ecosystem function.

What the Data Show

Nitrate export from the Mississippi River has been monitored

since the mid-1950s and from the Susquehanna, St. Lawrence,

and Columbia Rivers since the 1970s, and is reported in The

State of the Nation’s Ecosystems in tons per year. The load in

the Mississippi River has fluctuated from year to year, but it has

increased from approximately 250,000 tons per year in the

early 1960s to approximately 1,000,000 tons per year during

the 1980s and 1990s (The Heinz

Center, 2002) (Exhibit 5-43). 

The Mississippi River drains the agricultural “breadbasket” of the nation

and contains a large percentage of

the growing population, so the

increases likely reflect failure to 

control nitrogen pollution, rather than

a breakdown in ecosystem function

(e.g., Rabalais and Turner, 2001).

Nitrate loads in the other three rivers

have fluctuated around 50,000 tons

per year since the 1970s, although

the Columbia River spiked to

100,000 tons per year in the 

late 1990s. 

Indicator Gaps and Limitations

The indicator does not include data from numerous coastal watersheds whose human populations are rapidly increasing and are

therefore estimated to have high nitrogen loss rates (e.g., Valigura,

et al., 2000). It also does not include other forms of nitrogen

besides nitrate, which may constitute a substantial portion of the

nitrogen load.

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data collected by the

U.S. Geological Survey, National Stream Quality Accounting

Network and National Water Quality Assessment Program, and by

the U.S. Army Corps of Engineers. (See Appendix B, page B-49,

for more information.)

Nitrate Load (thousand tons N/year)

Exhibit 5-43: Nitrate load carried by major rivers, 1970-1999

Mississippi

Susquehanna

St. Lawrence

Columbia

Detail

0

500

1000

1500

2000

2500

1950 1960 1970 1980 1990 2000

0

50

100

1970 1980 1990 2000

Coverage: selected major rivers.

Source: The Heinz Center. The State of the Nation's Ecosystems. 2002.

Data from the U.S. Geological Survey's National Stream Quality Network (NASQAN), 

National Water Quality Assessment (NAWQA), and Federal-State Cooperative Program. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.8 What Is the Ecological Condition of the Entire Nation? 5-71

Indicator Chemical contamination – Category 2

This indicator has been discussed for the individual ecosystems,

but here it is reported for all media, regardless of land-cover type.

The following is a summary of the key findings; the Heinz report

(2002) should be consulted for further details. 

What the Data Show

Three-fourths of all streams in the National Water Quality

Assessment (NAWQA) network had one or more contaminants

that exceeded guidelines for the protection of aquatic life, and

one-fourth had four or more contaminants over those levels. Onefourth of ground water wells sampled had one or more contaminants above human health standards. One-half of all streams had

one or more contaminants in sediments that exceeded wildlife

protection guidelines (usually more stringent than criteria to protect human health). One-half of all fish tested had one or more

contaminants that exceeded wildlife protection guidelines.

Approximately 60 percent of estuarine sediments tested had concentrations of contaminants expected to lead to “possible effects”

in aquatic life, and 2 percent had concentrations exceeding levels

expected to have “likely effects.”

Indicator Gaps and Limitations

The limitations of this indicator include the following: 

Q While these data represent a comparison of a standard to the

respective contaminant concentration, they do not represent

assessments of risk posed to humans or ecosystems. 

Q Different standards also reflect different levels of protection, so

these data should be interpreted cautiously. 

Q Media contamination, such as water or sediment contamination,

does not necessarily indicate exposure to the contaminant for

either humans or other biological populations. 

Data Source

The data source for this indicator was The State of the Nation’s

Ecosystems, The Heinz Center, 2002, using data from the National

Water Quality Assessment Program and the Environmental

Monitoring and Assessment Program, Estuaries Program. 

(See Appendix B, page B-50, for more information.)
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-72 5.8 What Is the Ecological Condition of the Entire Nation? Chapter 5 - Ecological Condition

Summary: The Ecological Condition of the Entire Nation

The idea of monitoring indicators that could include the entire

nation, irrespective of the type of land cover, has not been a main

topic of ecological monitoring. The main idea is that pressures acting

over large areas may have effects that transcend a land cover type,

or may depend on the interaction of land cover types. The issue of

scale has not been well-articulated with respect to these indicators

(issues of national scope may not operate at national scales). This is

an area of attention for future reports.

Landscape condition

The National Land Cover Database (NLCD) now provides a consistent national picture of the extent of the various ecosystem types at

30 meter (about 100 foot) resolution (Vogelmann, et al., 2001). A

consortium of federal agencies performs the interpretation of the

satellite data necessary for development of the NLCD. Much of the

data in this indicator come from the Forest Inventory and Analysis

(FIA) or the National Resources Inventory (NRI), which allows trends

to be estimated during periods prior to the first NLCD coverage.

Unfortunately, these data are not comparable to the NLCD, because

of differences in the definitions of the land cover categories (see

Chapter 3, Better Protected Land).

Biotic condition

With respect to the at-risk native species indicator, the NatureServe

database is an invaluable resource for identifying these species.

Because the resulting data are developed without an underlying 

statistical design, however, it will be difficult to determine whether

future trends are the result of more thorough field work and reporting by researchers and resource managers, or actual trends in the

number of at-risk species. An effort has begun to identify all species

in the Smoky Mountain National Park (Kaiser, 1999), and an 

international effort, called Species 2000, is being developed by a

multinational project team associated with the United Nations (U.N.)

Convention of Biological Diversity. Recent research expanding the

bird diversity index to the entire mid-Atlantic region shows that it

has promise as a national indicator (O’Connell, et al., 2002).

Analysis of the biological data from the first 20 National Water

Quality Assessment (NAWQA) study units, and similar analyses of

Environmental Monitoring and Assessment Program (EMAP) data

from the national estuaries and streams in the West and Midwest,

should shed some light on the feasibility of a national indicator for

estuarine and stream benthic communities. Because the plankton

communities of lakes do not exhibit a high degree of biogeographical

variation (independent of natural factors such as hardness or the

presence of organic color), a national plankton index would seem

feasible if the necessary data were collected.

Ecological processes

The Terrestrial Plant Growth Index is probably the best example of the

indicator of primary productivity called for by both the NRC (2000)

and SAB (2002). Comparable data exist on trends for a decade, with

census coverage (at the resolution of the AVHRR sensor) for the

conterminous U.S. Examination of the trends data for this indicator

in The Heinz Center (2002) report shows large (±40 percent)

excursions from the 11-year average in the Southwest, and ±20 percent excursions in the Pacific region. The amount of time necessary

to separate changes caused by air pollutants (e.g., ozone, nitrogen

deposition, carbon dioxide) from those caused by natural climatic

factors and insect and disease outbreaks is unknown. 

The Movement of Nitrogen indicator certainly captures trends in this

important nutrient in the nation’s largest river basins. The indicator

would be improved if it included total nitrogen, including an accurate

estimate of nitrogen carried in the bed load of sediments as it moves

into coastal waters, and if it were extended to the many smaller

coastal watersheds that are experiencing large increases in population. An indicator of sediment runoff potential would be a useful

large-ecosystem indicator if it were extended to non-farmland

ecosystems (see Chapter 3, Better Protected Land).

Chemical and physical characteristics

The Chemical Contamination indicator raises a serious question about

how representative the streams in the NAWQA study units are.

There were 119 NAWQA sites with surface water monitoring data,

located in 20 geographically well-dispersed watersheds across the

U.S. Eventually, NAWQA plans to expand to 60 such units, and presumably all will include water sampling. On a national basis, this

might be an adequate number to represent the range of factors

affecting ecological condition of the streams and watersheds. The

number of streams characterizing forest, farmland, or urban/suburban watersheds seems too small, however, given the very wide range

of nutrient and contaminant concentrations presented in the Heinz

report.

More important, however, is whether the streams sampled are representative of the range of streams in the entire nation. The ecological

condition of fresh waters (and their watersheds) reflects the sum

total of natural factors (including disturbances), conscious and

unconscious decisions about land-use management (e.g., what crops

to grow, whether and when to cut timber, urban planning and zoning), and the presence and control of pollutants. A particular stream

might be representative of a watershed with respect to geomorphology and hydrology, and even land use (e.g., corn or tree farming,

urban or suburban). But resource management decisions and the

presence or control of pollutants are particular to a specific watershed, and so the streams must be chosen to be representative of the

full range of possibilities, and of their relative frequencies. With

respect to pollution control, assuming that the full set of environmental controls are working as envisioned by EPA is particularly risky.

In fact, this risk is one of the primary reasons for monitoring
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.8 What Is the Ecological Condition of the Entire Nation? 5-73

progress toward national goals under GPRA; to determine if the programs, as implemented and enforced by the states are really protecting and restoring the biological integrity of fresh waters. In this context, identifying representative streams or watersheds is not as reasonable as identifying representative samples of streams or watersheds. Until the NAWQA streams can be compared to a statistically

representative sample of streams, great care must be taken in assuming that the data accurately reflect the national condition of fresh

waters and watersheds.

There were no Category 1 or 2 indicators available for this report

for hydrology and geomorphology or natural disturbance regimes, but

developing them does not seem to be a particularly daunting 

challenge, given the widely available data on geology, flow, and 

paleological methods to indicate the regional occurrence of climatic

events and fire.
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-74 5.9 Challenges and Data Gaps Chapter 5 - Ecological Condition

5.9 Challenges and 

Data Gaps

The availability of indicators across ecosystem types is summarized in

Exhibit 5-44. Indicators that currently can provide national information on ecological condition are available for only 14 of the possible

126 indicator categories in the framework. More than half of the

Category 1 indicators provide information only on ecosystem extent

and landscape composition, with a few exceptions:

Q The Forest Inventory and Analysis (FIA) and Forest Health

Monitoring (FHM) programs together have achieved representative

national coverage for both the present status and historical trends

in the occurrence of fire, insect damage, and disease for forests. 

Q Satellite data provide continent-wide status and trends in the

Normalized Difference Vegetation Index (NDVI), which serves as a

surrogate for primary productivity, or the amount of energy

available at the base of the ecosystems.17

Q Historical hydrology data were analyzed for The Heinz Center

report to determine trends in high and low-flows for more than

800 streams with no specified land cover and more than 500

forest streams across the U.S., and the number and duration of

dry periods were calculated for 152 streams in grasslands,

shrublands, and dry areas. These analyses could presumably have

been performed for urban/suburban, agricultural, and very large

watersheds, but they have not been performed to date. 

Q The current status and historical trends in the potential for

sediment transport from farmland can be calculated from existing

data (though not the amount of sediment actually lost).

For the rest of the essential ecological attributes, only partial data

exist, at best (e.g., regional data or data for only part of the

resource), for one or more indicators. For more than one-half of the

major indicator categories in the seven ecosystem types, not even

one indicator was identified for this report. For many more, only one

existed, though several would be necessary. This situation will

improve slightly in the next year or two. A number of active research

programs are collecting and analyzing relevant ecological condition

data at the national or regional level, but the results had not yet met

the criterion for peer review at the time this report was finalized. Two

years from now, research on indicators from the FIA program, FHM

program, the National Water Quality Assessment (NAWQA) program,

and the Environmental Monitoring and Assessment Program ( EMAP)

Western Streams Pilot should provide new Category 2, and a few

Category 1 indicators, primarily biotic condition and ecological

process indicators. As of now, the gaps are substantial.

What the Available Indicators Reveal about Some

Ecological Issues of Recent Concern to EPA

The introduction to this chapter identified three reasons to monitor

ecological condition:

Q To establish baselines against which to assess the current and

future condition of ecosystems.

Q To provide a warning that action may be required.

Q To track the outcomes of policies and programs, and adapt them

as necessary.

This section addresses the question of how well the available 

indicators of ecological condition, notwithstanding the gaps evident

in Exhibit 5-44, serve these purposes for some ecological issues that

have been of concern to EPA over the past decade. These do not

reflect all such issues, or signify EPA’s priorities, but simply typify a

diverse set of challenges for national ecological monitoring: 

Q Forest dieback

Q Vertebrate deformities

Q Harmful algal blooms

Q Eutrophication

Q Loss of biodiversity

Q Non-target organism effects from pesticides and herbicides

Q Issues related to ozone, UV-B, mercury, acidic deposition, and

persistent bioaccumulative toxics (PBTs)

For the first five issues listed above, biota were harmed before the

cause was known. For the other two, a perceived risk exists, but the

extent of actual harm or exposure is unknown. In either case, data on

the extent or trends in ecological condition is needed to inform how

research is targeted or regulatory programs adjusted. Identifying indicators of the appropriate essential ecological attribute also should help

to identify some of the factors that might be contributing to the

extent of and trends in harm to biota and ecosystem function (EPA,

SAB, 2002).

Forest dieback

Forest dieback can be exacerbated, if not caused, by some combination of acid deposition, air pollution, UV-B radiation, disease, insects,

and unusual climate events (USDA, FS, 2002). Currently, the forest

indicators provide a baseline for the extent of poor tree condition in

37 states; soon, these indicators will provide a baseline and future

trends for the conterminous U.S. NDVI data are available as a surrogate for primary productivity in forests. FIA program plots are being

examined for indications of harm to ozone-sensitive species. Relevant

17There is some debate as to whether standing crop chlorophyll can soil data (exchangeable base cations) are being measured, even

really be a surrogate for primary productivity, so this might be more appropriate as an ecosystem condition indicator.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 55.9 Challenges and Data Gaps 5-75

though that indicator cannot yet be reported. A UV-B monitoring

network has been collecting data for less than 2 years, and the data

are currently being evaluated. Data for ozone and acid deposition in

high elevation forests remain poor, as do climate data. Most of these

indicators are being monitored using a probability design, so continued FIA monitoring can provide a national baseline for assessing the

extent and trends in forest dieback, and some of the EEAs that may

contribute to it.

Vertebrate deformities

The ability of exogenous chemicals to interfere with normal

endocrine functioning and related processes of an organism has

raised increasing concerns for human health and the environment.

Studies have reported that both synthetic and naturally occurring

compounds interfere with normal endocrine function of invertebrates, fish, amphibians, reptiles, birds, and mammals causing effects

such as birth defects, impaired fertility, masculinization of female

organisms, feminization of male organisms, or organisms with both

male and female reproductive organs. Two recent reports summarize

available data from field and laboratory studies and provide an

assessment of the state of the science (EPA, RAF, 1997; IPCS, 2002).

The existing challenge is to further elucidate the cause-and-effect

relationships for the observed adverse effects, determine which

chemicals are of greatest concern, and the extent to which these

chemicals negatively impact populations of fish and/or wildlife. 

The only indicator identified in this chapter that tracks the extent or

trends in animal deformities (irrespective of the cause) is a Category

2 indicator, Fish Deformities, collected by EMAP in coast and ocean

ecosystems. Data are being collected on amphibian deformities by

the USGS, using reports from a wide array of sources. A new national

survey, the Amphibian Research and Monitoring Initiative, was established by USGS in 2000. However, it may be several years before

USGS and EPA can detect national and/or regional trends from this

initiative. Until there is a better understanding of which chemicals are

of greatest concern, there is also some question about which chemiEssential Ecological Attribute 

Landscape Condition 

Extent of Ecological System/Habitat Types 

Landscape Composition 

Landscape Pattern/Structure 

Biotic Condition 

Ecosystems and Communities 

Species and Populations 

Organism Condition 

Ecological processes 

Energy Flow 

Material Flow 

Chemical & Physical Characteristics 

Nutrient Concentrations 

Other Chemical Parameters 

Trace Organic /Inorganic Chemicals 

Physical Parameters 

Hydrology and Geomorphology 

Surface and Ground Water Flows 

Dynamic Structural Conditions 

Sediment and Material Transport 

Natural Disturbance Regimes 

Frequency 

Extent 

Duration

Note: Numbers correspond to indicator categories presented in this report. 

Exhibit 5-44: Distribution of available ecological condition indicators across the ecosystem types

Forests Farmlands Grasslands/ Urban/ Fresh Coasts and The 

 Shrublands Suburban Waters Oceans Nation
EPA’s Draft Report on the Environment 2003 Q Technical Document

5-76 5.9 Challenges and Data Gaps Chapter 5 - Ecological Condition

cals to monitor in the fish and wildlife habitat. Additional information

on chemicals will become available once EPA has fully implemented

an Endocrine Disruptor Screening Program to test a chemical for its

potential endocrine disruption activity. 

Harmful algal blooms

Scientists have also been concerned about the condition of the

nation’s estuaries and in particular, about a perceived increase in

harmful algal blooms (HABs); loss of submerged aquatic vegetation

(SAV), which serves as habitat for fish; and sediment toxicity, which

might limit the productivity of an important component of the

estuarine food chain (Anderson and Garrison, 2000; Gallagher and

Keay, 1998). EMAP, working with the states, has collected data on the

condition of SAV, estuarine fish communities, estuarine benthic

communities, sediment toxicity, and nutrient concentrations that

should provide representative status and trends data for these

indicators. The sampling design does not allow tracking of the

frequency and extent of HABs or nutrient levels in estuaries, but USGS

does monitor nutrient loads to coastal systems from four of the largest

U.S. rivers. Continued monitoring of the estuaries is subject to stateby-state availability of funding.

Eutrophication

EPA has recently focused substantial attention on the listing by the

states of their waters that do not meet their designated uses (usually

expressed in terms of their ability to support aquatic life), and developing total maximum daily loads of pollutants that would allow the

designated use to be achieved. Concern over eutrophication of lakes

and reservoirs has prompted EPA to begin developing regional standards for the nutrients nitrogen and phosphorus. At present, there is

no indicator monitoring suitable to track progress in reducing the

number of eutrophic lakes and streams or the condition of the biotic

communities in rivers and streams at the national or even regional

level. Indicators monitored by the states are not comparable, the

same waters are not necessarily sampled over time, and their representativeness is unknown and questionable. NAWQA uses comparable methods and intends to monitor the same streams over time, but

the number of such streams in the various ecosystem types is too

small to adequately represent all the factors that contribute to water

quality at the national level. While the data are likely to be broadly

representative of certain types of streams, they cannot be expanded

to all streams with known statistical reliability. This fact is particularly

important if the combination of factors affecting water quality in the

study units (which depend on a variety of factors, including water

quality management by the states, national patterns of air pollution

and acid rain, geology and land use, and climate) is not statistically

representative of these factors nationally. EMAP has demonstrated

regional approaches to statistically representative sampling that

include both biology and chemistry, but has not yet reported on

relationships between them, nor is there any long-term commitment

to repeating the pilot studies or expanding them to other regions.

EPA is currently working with the states to rectify this situation, and

some progress is reported in Chapter 2, Purer Water.

Loss of biodiversity

EPA is concerned generally about biodiversity, and this is one of the

primary areas on which EPA comments in Environmental Impact

Statements for significant projects involving federal funding under

NEPA. The NatureServe indicator reported for many of the ecosystems is invaluable in indicating species at risk in the vicinity of such

projects. Because the database is not based on a systematic survey

of plots over time, however, it is not clear how to interpret data that

are not reported. For example, the current data cannot distinguish

naturally rare species from species whose numbers have been

reduced. It is not clear how to determine whether future trends are

the result of better (or less) field work or the actual status of the

species in question. The answer likely depends on the species, but at

this point the data seem less than ideal for national reporting.

Non-target organism effects from pesticides and herbicides

EPA is concerned about non-target organism effects from pesticides

and herbicides. Pesticides and herbicides (including those

incorporated into the genomes of crops) are registered for use by

EPA such that their use in accordance with the registration is not

expected to pose unnecessary risks to non-target organisms.

Nonetheless, neither the models nor the compliance are likely to be

perfect, so tracking any residues of such pesticides in non-target

organisms would be useful, as would identifying any harm or

mortality of organisms that might be caused by improper use of

pesticides. There are Category 2 indicators for pesticide application

and leaching pesticides in stream biota, and pesticides in sediment

and fish tissue for fresh waters. There are no indicators in The Heinz

Center report for pesticides in terrestrial organisms. Another

indicator that might provide presumptive evidence of harm—animal

die-off in fresh waters—is adequate for national reporting only for

waterfowl.
Technical Document Q EPA’s Draft Report on the Environment 2003

Chapter 5 - Ecological Condition 5.9 Challenges and Data Gaps 5-77

Issues related to ozone, UV-B, mercury, acidic deposition, and

persistent bioaccumulative toxics (PBTs)

In air, a number of pollutants travel regionally or even globally (e.g.,

ozone, acid deposition, PBTs [including mercury], ozone-depleting

substances, greenhouse gases). What do the indicators reveal about

baselines and trends in the levels of these pollutants in various

ecosystems, or possible harm to biota as a result of exposure to

these pollutants or their secondary effects? The chemical and physical characteristic EEA in Exhibit 5-44 contains many Category 2

indicators, but no indicators are available that provide a representative baseline for the nation. 

For water, the NAWQA program samples sediment chemistry in more

than 500 streams for many PBTs. Repeated sampling should provide

an invaluable picture of trends, unless the variability is too high or

there are important local sources that make these streams non-representative of streams in general. A smaller number of streams have

been sampled for contaminants in fish tissue. A national monitoring

network for mercury currently exists, with sampling sites primarily on

the East coast and in the upper Midwest (see Chapter 2, Purer

Water), but it is not adequate for establishing a national baseline for

mercury or other PBTs. Monitoring for UV-B exposure is under development by USDA. EMAP has collected fish tissue residues for many

of the PBTs, but there is no commitment to re-sample in the future. 

To the extent that these factors affect tree growth, FHM will provide

national trends information in the future, but at this point, there is

no prospect for establishing trends in either exposure or effects for

most of these chemicals.

Future Challenges

When the indicators available for this report are arrayed against the

essential attributes in Exhibit 5-44, it is clear that indicators and

adequate data are available to address only a portion of the information needed to describe ecological condition for the nation. Data for

a few more indicators have been collected once, or for limited geographic regions, but the clear message is that more data are needed

to describe and track ecological condition. This situation will improve

over the next few years, but most of the gaps in Exhibit 5-44 are

likely to remain for some time to come.

There are several challenges to developing adequate indicators of

ecological condition for the nation:

Q Indicators must be tied to conceptual models that capture how

ecosystems respond to single and multiple stressors at various

scales.

Q Federal, state, and local monitoring organizations must find a way

to coordinate and integrate their activities to meet multiple,

potentially conflicting, data needs.

Q Mechanisms must be found to ensure long-term commitments to

measuring selected indicators over long periods and in

standardized ways, to establish comparable baselines and trends.

Q Indicators must simplify complex data in ways that make them

meaningful and useful to decision-makers and the public.

None of these challenges appear insurmountable, but the gaps in

Exhibit 5-44 indicate the work that remains to allow measurement of

ecological condition at the national scale.
Appendix A: 

Databases 

and Reports

Supporting Major

Clusters of

Indicators Used in

the Report with 

Links for Additional

Information
EPA’s Draft Report on the Environment 2003 Q Technical Document

A-2 Databases and Reports Supporting Major Clusters of Indicators Used in the Report Appendix A

Appendix A: Databases and Reports Supporting Major

Clusters of Indicators Used in the Report with Links for

Additional Information

The databases that serve as the underlying datasets and the reports

that provide the majority of indicators used in the Draft Report on the

Environment Technical Document are listed by human health and

environmental categories in alphabetical order below. In the interests

of providing complete and accurate information, rather than provide

summary descriptions of the databases, links to the primary home

pages of the databases are noted as starting points for further investigation by interested readers. 

Human Health Databases

Database: National Center for Health Statistics (NCHS), National

Health and Nutrition Examination Survey (NHANES)

Web site: http://www.cdc.gov/nchs/nhanes.htm (NHANES)

Database: National Center for Health Statistics (NCHS), National

Health Interview Survey (NHIS)

Web site: http://www.cdc.gov/nchs/nhis.htm

Database: Environmental Protection Agency, Office of Research

and Development (ORD), National Human Exposure

Assessment Survey (NHEXAS)

Web sites: http://www.epa.gov/nerl/research/nhexas/nhexas.htm

(NHEXAS) and http://www.epa.gov/heds/ (NHEXAS data

in EPA’s Human Exposure Database System)

Database: Centers for Disease Control and Prevention,

Epidemiology Program Office, National Notifiable

Disease Surveillance System

Web sites: http://www.cdc.gov/mmwr/ (Morbidity and Mortality

Weekly Report) http://www.cdc.gov/epo/dphsi/annsum/

(Summary of Notifiable Diseases)

Database: National Center for Health Statistics (NCHS), National

Vital Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Database: National Institutes of Health (NIH), National Cancer

Institute (NCI), Surveillance, Epidemiology, and End

Results (SEER) Program

Web site: http://seer.cancer.gov/ 

Environmental Databases and Reports

Database: Environmental Protection Agency, Office of Air and

Radiation, Aerometric Information Retrieval System (AIRS)

Web site: AIRS and the Air Quality System—

http://www.epa.gov/ttnairs1/airsaqs/index.htm 

Database: Environmental Protection Agency, Office of Research

and Development, Environmental Monitoring and

Assessment Program (EMAP)

Web site: http://www.epa.gov/emap/

Database: U.S. Department of Agriculture, U.S. Forest Service,

Forest Health Monitoring (FHM) Program

Web site: http://www.na.fs.fed.us/spfo/fhm/index.htm

Database: U.S. Department of Agriculture, U.S. Forest Service,

Forest Inventory and Analysis (FIA)

Web site: http://fia.fs.fed.us

Report: Environmental Protection Agency, Office of Air and

Radiation, Latest Findings on National Air Quality: 2001

Status and Trends

Web site: http://www.epa.gov/oar/aqtrnd01/

Database: Multi-Resolution Land Characterization (MLRC)

Consortium, National Land Cover Dataset (NLCD)

Web sites: MRLC: http://www.epa.gov/mrlc/

NLCD: http://www.epa.gov/mrlc/nlcd.html

Database: U.S. Department of Agriculture, Natural Resources

Conservation Service, National Resources Inventory (NRI) 

Web site: http://www.nhq.nrcs.usda.gov/NRI/1997/

Database: U.S. Department of the Interior, U.S. Geological Survey, National

Stream Water Quality Accounting Network (NASQAN)

Web site: http://water.usgs.gov/nasqan/

Database: U.S. Department of the Interior, U.S. Geological Survey,

National Water Quality Assessment (NWAQA)

Web site: http://water.usgs.gov/nawqa/

Database: U.S. Department of the Interior, U.S. Fish and Wildlife

Service, National Wetlands Inventory (NWI)

Web site: NWI: http://www.nwi.fws.gov/ 

Database: NatureServe

Web site: http://www.natureserve.org

Report: U.S. Department of the Interior, U.S. Fish and Wildlife

Service, Status and Trends of Wetlands in the Conterminous

United States 1986 to 1997

Web site: http://www.nwi.fws.gov/bha/SandT/SandTReport.html

Report: The H. John Heinz III Center for Science, Economics, and the

Environment, The State of the Nation’s Ecosystems: Measuring the

Lands, Waters, and Living Resources of the United States

Web site: http://www.heinzctr.org/ecosystems

Database: Environmental Protection Agency, Office of Environmental

Information, Toxics Release Inventory (TRI)

Web site: http://www.epa.gov/tri/
Appendix B: 

Indicator 

Metadata
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-2 Indicator Metadata Appendix B

Terms Used in the

Indicator Metadata

Appendix

Indicator names are those presented in the text report of this.

Indicator type (status or trend) - Indicators are designated status

if the indicator is supported by a single data point or study, a

snapshot in time. Indicators are designated trends if there are at

least three data points.

Indicator category. Indicators were assigned to one of two

categories:

Q Category 1—The indicator has been peer reviewed and is

supported by national level data coverage for more than one time

period. The supporting data are comparable across the nation and

are characterized by sound collection methodologies, data

management systems, and quality assurance procedures.

Q Category 2—The indicator has been peer reviewed, but the

supporting data are available only for part of the nation (e.g.,

multi-state regions or ecoregions), or the indicator has not been

measured for more than one time period, or the not all the

parameters of the indicator have been measured (e.g., data has

been collected for birds, but not for plants or insects). The

supporting data are comparable across the areas covered, and are

characterized by sound collection methodologies, data

management systems, and quality assurance procedures.

All category designations for the indicators and associated data are

relative to the specific associated question. 

Spatial coverage is scale and geographic information about where

monitoring and sampling have taken place. 

Temporal coverage is the time period in which the data has been

collected and includes information about seasonality of collection

activity where relevant.

Characterization of supporting data set(s) is descriptive

information about the history of the database and its collection

methodologies, data management systems, and quality assurance

procedures.

Indicator source information, including derivation and web sites,

are provided for readers who want additional information.

Chapter 1: Cleaner Air

Outdoor Air Quality

Indicator name: Number and percentage of days that metropolitan

statistical areas (MSAs) have Air Quality Index (AQI) values greater

than 100

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What is the quality of outdoor air in the

United States?

Spatial coverage: National. Based on the measurements, EPA

designates geographical areas of attainment (meeting standards) and

nonattainment for specific criteria air pollutants.

Temporal coverage: 1988-2001. 

Characterization of supporting data set(s): The National Air

Monitoring Stations (NAMS) and the State and Local Air Monitoring

Stations network measures air quality at 5,200 monitors operating at

3,000 sites across the country, mostly in urban areas.

Measurements, taken on both a daily and continuous basis to assess

both peak concentrations and overall trends, are reported in the

Aerometric Information Retrieval Systems (AIRS). Trends are derived

by averaging direct measurements from these monitoring stations on

a yearly basis. Not all sites monitor all of the six criteria air

pollutants. The Air Quality System (AQS) database contains

measurements of criteria air pollutant concentrations in the 50

United States, plus the District of Columbia, Puerto Rico, and the

Virgin Islands.

EPA uses the AQI for five major air pollutants regulated by the Clean

Air Act (CAA): ground-level ozone, particulate matter, carbon

monoxide, sulfur dioxide, and nitrogen dioxide. In large metropolitan

areas (more than 350,000 people), state and local agencies are

required to report the AQI to the public daily. In 1976, EPA

developed the Pollutant Standards Index (PSI), a consistent and easy

to understand way of stating air pollutant concentrations and

associated health implications. In June 2000, EPA updated the index

and renamed it AQI. PSI and AQI are similar as they both focus on

health risks of brief exposure to pollutants (a few hours or days);

involve air pollutants regulated by the CAA (criteria pollutants); use

the same method to calculate index values; and use an index value of

100 to represent pollutant concentration at the level of the national

ambient standard set by EPA National Ambient Air Quality Standards

(NAAQS). Beginning in 2000, the AQI included new features

including a new health risk category, unhealthy for sensitive groups;

two additional pollutants (ozone averaged over 8 hours and fine

particulate matter less than 2.5 micrometers in size (PM2.5); and a

specific color associated with each of the health risk categories. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-3

Indicator derivation (project, program, organization, report):

For 1988 through 1991, data were drawn from U.S. Environmental

Protection Agency, Office of Air Quality Planning and Standards.

National Air Quality and Emissions Trends Report, 1997. Table A-15.

EPA 454-R-98-016. Research Triangle Park, NC: EPA. December,

1998. For 1992 through 2001, data were drawn from U.S.

Environmental Protection Agency, Office of Air Quality Planning and

Standards. Air trends: Metropolitan area trends, Table A-17. 2001.

(February 25, 2003; http://www.epa.gov/airtrends/metro.html).

Web sites: AIRS and AQS

http://www.epa.gov/ttnairs1/airsaqs/index.htm; 

1997 air quality trends report

http://www.epa.gov/oar/aqtrnd97/tables.html; 

2000 air quality trends tables

http://www.epa.gov/airtrends/metro.html/;

AQI background

http://www.epa.gov/airnow/aqibroch/

Indicator name: Number of people living in areas with air quality

levels above the National Ambient Air Quality Standards (NAAQS)

for particulate matter (PM) and ozone

Indicator type (status or trend): Trend

Indicator category (1 and 2): 1

Associated question: How many people are living in areas with

particulate matter and ozone levels above the National Ambient Air

Quality Standards (NAAQS)?

Spatial coverage: National. Based on the measurements, EPA

designates geographical areas of attainment (meeting standards) and

nonattainment for specific criteria air pollutants.

Temporal coverage: 2001

Characterization of supporting data set(s): The National Air

Monitoring Stations (NAMS) and the State and Local Air Monitoring

Stations (SLAMS) network measure air quality at 5,200 monitors

operating at 3,000 sites across the country, mostly in urban areas.

Measurements, taken on both a daily and continuous basis to assess

both peak concentrations and overall trends, are reported in the

Aerometric Information Retrieval Systems (AIRS). Trends are derived

by averaging direct measurements from these monitoring stations on

a yearly basis. Not all sites monitor all of the six criteria air

pollutants. 

Indicator derivation (project, program, organization, report):

Aerometric Information Retrieval System (AIRS), the repository of

data collected from the NAMS and the SLAMS is reported in U.S.

Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web sites: AIRS and AQS

http://www.epa.gov/ttnairs1/airsaqs/index.htm; 

Air quality trends report http://www.epa.gov/oar/aqtrnd01/

Indicator name: Ambient concentrations of particulate matter

(PM2.5 and PM10) 

Indicator type (status or trend): Status

Indicator category (1 and 2): 1

Associated question: What are the concentrations of some criteria

air pollutants: PM2.5, PM10, ozone, and lead?

Spatial coverage: National. Based on the measurements, EPA designates geographical areas of attainment (meeting standards) and

nonattainment for specific criteria air pollutants. 

Temporal coverage: 1982-2001

Characterization of supporting data set(s): The National Air

Monitoring Stations (NAMS) and the State and Local Air Monitoring

Stations (SLAMS) network measure air quality at 5,200 monitors

operating at 3,000 sites across the country, mostly in urban areas.

Measurements, taken on both a daily and continuous basis to assess

both peak concentrations and overall trends, are reported in the

Aerometric Information Retrieval Systems (AIRS). Trends are derived

by averaging direct measurements from these monitoring stations on

a yearly basis. Not all sites monitor all of the six criteria air

pollutants. In 1999, EPA and its state, tribal, and local air pollution

control agency partners deployed a monitoring network to begin

measuring PM2.5 concentrations nationwide. The PM2.5 data

presents was drawn from AIRS as of July 8, 2002. 770 sites have

sufficient PM10 to assess trends from 1992-2001.

Indicator derivation (project, program, organization, report):

Aerometric Information Retrieval System (AIRS), the repository of

data collected from the NAMS and the SLAMS is reported in U.S.

Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web sites: AIRS and AQS

http://www.epa.gov/ttnairs1/airsaqs/index.htm; 

Air quality trends report http://www.epa.gov/oar/aqtrnd01/

Indicator name: Ambient concentrations of ozone, 8-hour and 

1-hour 

Indicator type (status or trend): Status

Indicator category (1 and 2): 1

Associated question: What are the concentrations of some criteria

air pollutants: PM2.5, PM10, ozone, and lead?
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-4 Indicator Metadata Appendix B

Spatial coverage: National. Based on the measurements, EPA designates geographical areas of attainment (meeting standards) and

nonattainment for specific criteria air pollutants. 

Temporal coverage: 1982-2001

Characterization of supporting data set(s): The National Air

Monitoring Stations (NAMS) and the State and Local Air Monitoring

Stations (SLAMS) network measure air quality at 5,200 monitors

operating at 3,000 sites across the country, mostly in urban areas.

Measurements, taken on both a daily and continuous basis to assess

both peak concentrations and overall trends, are reported in the

Aerometric Information Retrieval Systems (AIRS). Trends are derived

by averaging direct measurements from these monitoring stations on

a yearly basis. Not all sites monitor all of the six criteria air pollutants. 379 sites have sufficient data to assess trends from 1992-

2001 for both 8-hour and 1-hour measurements.

Indicator derivation (project, program, organization, report):

Aerometric Information Retrieval System (AIRS), the repository of

data collected from the NAMS and the SLAMS is reported in U.S.

Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web sites: AIRS and AQS

http://www.epa.gov/ttnairs1/airsaqs/index.htm; 

Air quality trends report http://www.epa.gov/oar/aqtrnd01/

Indicator name: Ambient concentrations of lead

Indicator type (status or trend): Trend

Indicator category (1 and 2): 1

Associated question: What are the concentrations of some criteria

air pollutants: PM2.5, PM10, ozone, and lead?

Spatial coverage: National. Based on the measurements, EPA designates geographical areas of attainment (meeting standards) and

nonattainment for specific criteria air pollutants. 

Temporal coverage: 1982-2001

Characterization of supporting data set(s): The National Air

Monitoring Stations (NAMS) and the State and Local Air Monitoring

Stations (SLAMS) network measure air quality at 5,200 monitors

operating at 3,000 sites across the country, mostly in urban areas.

Measurements, taken on both a daily and continuous basis to assess

both peak concentrations and overall trends, are reported in the

Aerometric Information Retrieval Systems (AIRS). Trends are derived

by averaging direct measurements from these monitoring stations on

a yearly basis. Not all sites monitor all of the six criteria air pollutants. EPA has over 200 lead monitoring sites for lead nationally in

addition to special purpose monitors near smelters and other lead

emitters. The lead trend is based on 39 monitors that have a full 20

years of complete data.

Indicator derivation (project, program, organization, report):

Aerometric Information Retrieval System (AIRS), the repository of

data collected from the NAMS and the SLAMS is reported in U.S.

Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web sites: AIRS and AQS

http://www.epa.gov/ttnairs1/airsaqs/index.htm; 

http://www.epa.gov/oar/aqtrnd01/

Indicator name: Visibility

Indicator type (status or trend): Trend

Indicator category (1 and 2): 1

Associated question: What are the impacts of air pollution on visibility in national parks and other protected lands?

Spatial coverage: National. 30 sampling sites located in national

parks and wilderness areas through 1999; 110 sites after 2000 in

the monitoring network with an additional 20 sites using the monitoring protocol. Applicable to 156 Class I areas, mostly national

parks and wilderness areas in the eastern and western U.S.

Temporal coverage: 1992-1999 and 1990-1999 

Characterization of supporting data set(s): Data are presented by

mean visual range as measured in kilometers respectively by worst,

mid-range, and best visibility. The Interagency Monitoring of

Protected Visual Environments (IMPROVE) network was established

in 1987 as a cooperative effort among EPA, states, the National Park

Service, the U.S. Forest Service, the Bureau of Land Management,

and the U.S. Fish and Wildlife Service. Data are collected and analyzed from this network to determine the type of pollutants primarily

responsible for reduced visibility and to track progress toward the

Clean Air Act’s national goal.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web site: Air quality trends report

http://www.epa.gov/oar/aqtrnd01/

Indicator name: Ambient concentrations of selected air toxics

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are the concentrations of toxic air pollutants in ambient air?

Spatial coverage: National, but no formal monitoring network in

place limiting information.
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-5

Temporal coverage: 1994-2000

Characterization of supporting data set(s): Selected air toxics

only, not all 188 identified in the Clean Air Act (CAA). Ambient

concentrations are based on annual averages from the reporting

sites. EPA and the states do not maintain an extensive nationwide

monitoring network for air toxics as they do for the criteria air

pollutants. While EPA, states, tribes, and local air regulatory agencies

collect monitoring data for a number of toxic air pollutants, both the

chemicals monitored and the geographic coverage of the monitors

vary from state to state. Measurements of benzene were taken from

95 urban monitoring sites around the country. These urban areas

generally have higher levels of benzene than other areas of the

country.

Indicator derivation (project, program, organization, report):

The data come from a combination of several monitoring networks,

including: Photochemical Assessment Monitoring Stations Program;

Urban Air Toxics Monitoring Program; Non-Methane Organic

Compound Monitoring Program; Interagency Monitoring of

Protected Visual Environments (IMPROVE) Network. Reported in U.S.

Environmental Protection Agency, Latest Findings on National Air

Quality: 2001 Status and Trends, EPA 454-K-02- 001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.

Web site: Air quality trends report

http://www.epa.gov/oar/aqtrnd01/

Indicator name: Emissions: particulate matter (PM2.5 and PM10),

sulfur dioxide, nitrogen oxides, and volatile organic compounds

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are contributors to particulate matter,

ozone, and lead in ambient air?

Spatial coverage: National

Temporal coverage: 1992-2001

Characterization of supporting data set(s): Actual emissions data

are not presented and estimates are used. EPA estimates nationwide

emissions of ambient pollutants and their precursors based on actual

monitored readings or engineering calculations of the amounts and

types of pollutants emitted by vehicles, factories, and other sources.

Emission estimates are based on many factors, including the level of

industrial activity, technology developments, fuel consumption, vehicle miles traveled, and other activities that cause air pollution 

(EPA, OAQPS, September 2002). Consistent estimation methods

have been developed to provide trend data. Estimation is particularly

necessary for mobile sources and area-wide sources. The methodology for estimating emissions is continually reviewed and is subject to

revision. EPA is currently conducting such an evaluation of emissions

data, and emissions estimates may be updated. Trend data prior to

revisions must be considered in the context of those changes.

Emission estimates also reflect changes in air pollution regulations

and installation of emission controls. 

Indicator derivation (project, program, organization, report):

The National Emissions Inventory (NEI) for Criteria and Hazardous

Air Pollutants (HAPs) is a composite of many data sources reported

in U.S. Environmental Protection Agency, Latest Findings on National

Air Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002. In

the NEI, EPA divides emissions into four types of sectors: 1) major

(large industrial) sources; 2) area and other sources, which include

smaller industrial sources like small dry cleaners and gasoline

stations, as well as natural sources like wildfires; 3) onroad mobile

sources, including highway vehicles; and 4) nonroad mobile sources

like aircraft, locomotives, and construction equipment (EPA, OAQPS,

September 2002). 

Web site: Air quality trends report

http://www.epa.gov/oar/aqtrnd01/

Indicator name: Lead emissions

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are contributors to particulate matter,

ozone, and lead in ambient air?

Spatial coverage: National

Temporal coverage: 1982-2001

Characterization of supporting data set(s): EPA estimates nationwide emissions of ambient pollutants and their precursors based on

actual monitored readings or engineering calculations of the

amounts and types of pollutants emitted by vehicles, factories, and

other sources. Emission estimates are based on many factors, including the level of industrial activity, technology developments, fuel

consumption, vehicle miles traveled, and other activities that cause

air pollution (EPA, OAQPS, September 2002). Consistent estimation

methods have been developed to provide trend data. Estimation is

particularly necessary for mobile sources and area-wide sources. The

methodology for estimating emissions is continually reviewed and is

subject to revision. EPA is currently conducting such an evaluation of

emissions data, and emissions estimates may be updated. Trend data

prior to revisions must be considered in the context of those

changes. Emission estimates also reflect changes in air pollution 

regulations and installation of emission controls. 

Indicator derivation (project, program, organization, report):

The National Emissions Inventory (NEI) for Criteria and Hazardous

Air Pollutants (HAPs) is a composite of many data sources reported

in U.S. Environmental Protection Agency, Latest Findings on National

Air Quality: 2001 Status and Trends, EPA 454-K-02-001, Washington,

DC: EPA., Office of Air Quality and Standards, September 2002.
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-6 Indicator Metadata Appendix B

Web site: Air quality trends report

http://www.epa.gov/oar/aqtrnd01/

Indicator name: Air toxics emissions

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are contributors to toxic air pollutants

in ambient air?

Spatial coverage: National

Temporal coverage: 1990-1993, 1996

Characterization of supporting data set(s): Hazardous air pollutant estimates are currently available for 1990-1993 (a mix of years

depending on data availability on various source types) and 1996.

EPA compiles an air toxics inventory as part of the National

Emissions Inventory (NEI, formerly the National Toxics Inventory) to

estimate and track national emissions trends for the 188 toxic air

pollutants regulated under the CAA. In the NEI, EPA divides emissions into four types of sectors: 1) major (large industrial) sources;

2) area and other sources, which include smaller industrial sources

like small dry cleaners and gasoline stations, as well as natural

sources like wildfires; 3) onroad mobile sources, including highway

vehicles; and 4) nonroad mobile sources like aircraft, locomotives,

and construction equipment. The data presented are based on the

data in the NEI (EPA, OAQPS, September 2002).

Indicator derivation (project, program, organization, report):

The NEI for Criteria and Hazardous Air Pollutants (HAPs) is a composite of many data sources reported in U.S. Environmental

Protection Agency, Latest Findings on National Air Quality: 2001

Status and Trends, EPA 454-K-02-001, Washington, DC: EPA., Office

of Air Quality and Standards, September 2002.

Web site: Air quality trends report

http://www.epa.gov/oar/aqtrnd01/

Acid Deposition

Indicator name: Deposition: wet sulfate and wet nitrogen 

Indicator type (status or trend): Status comparison

Indicator category (1 and 2): 2

Associated question: What are the deposition rates of pollutants

that cause acid rain?

Spatial coverage: NADP/NTN consists of over 250 sites in the 

continental U.S., Alaska, Puerto Rico, and the Virgin Islands. 

Temporal coverage: 1989-1991, 1999-2001

Characterization of supporting data set(s): 1) The data is collected by uniform methods/protocol under the National Atmospheric

Deposition Program (NADP)/National Trends Network (NTN) and

the Clean Air Status and Trends Network (CASTNet). The NADP is a

cooperative program among federal and state agencies, universities,

electric utilities, and other industries that has measured precipitation

chemistry in the U.S. since 1978. The NADP/NTN is a nationwide

network of precipitation monitoring sites designed to measure

regional levels of atmospheric deposition. The NADP/NTN measures

wet acid deposition that occurs in rain, snow, or sleet) weekly at

about 250 monitoring stations throughout the U.S. The data are

subject to strict quality assurance and completeness screening in the

field, in the laboratory, and during analysis. 2) Presented total sulfur

and total nitrogen data are derived from CASTNet, a nationwide 

network of over 70 sites concentrated in the eastern continental U.S.

that measure ambient air concentrations of pollutants, including

ozone. CASTNet has not yet completed its expansion into the Great

Plains and western states. CASTNet also measures dry deposition

(the process through which particles and gases are deposited in the

absence of precipitation) of acidic compounds. CASTNet data are

also subject to strict quality assurance and completeness criteria

(EPA, OAR, November 2002).

Indicator derivation (project, program, organization, report):

NADP/NTN and CASTNet data are reported in U.S. Environmental

Protection Agency, EPA Acid Rain Program: 2001 Progress Report, EPA

430-R-02-009, Washington, DC: EPA, Office of Air and Radiation,

November, 2002.

Web site: NADP/NTN Data Access http://nadp.sws.uiuc.edu/

Indicator name: Emissions (utility): sulfur dioxide and nitrogen

oxides 

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are the emissions of pollutants that

form acid rain?

Spatial coverage: Over 2000 facilities nationally.

Temporal coverage: 1980, 1985, 1990, 1995, 2000, 2001

Characterization of supporting data set(s): Data collected by regulated facilities using certified continuous emissions monitors or equivalent, beginning in 1994-95 with quarterly and annual totals tabulated

for each facility and aggregated for plants, states, and the U.S.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. EPA Acid Rain Program: 2001

Progress Report, EPA 430-R-02-009. Washington, DC: U.S.

Environmental Protection Agency, Office of Air and Radiation,

November 2002. Appendix A: Acid Rain Program - Year 2001 SO2

Allowance Holdings and Deductions. (April 8, 2003;

http://www.epa.gov/airmarkets/cmprpt/arp01/appendixa.pdf) and

Appendix B1: 2001 Compliance Results for NOX Affected Units.

(April 8, 2003; http://www.epa.gov/airmarkets/cmprpt/arp01/ appendixb1.pdf).

Web site: http://www.epa.gov/airmarkets/emissions/index.html
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-7

Indoor Air Quality

Indicator name: U.S. homes above EPA’s radon action levels

Indicator type (status or trend): Status

Indicator category (1 and 2): 2

Associated question: What is the quality of the air in buildings in

the United States?

Spatial coverage: National

Temporal coverage: 1989-1990

Characterization of supporting data set(s): The National Radon

Residential Study of 1989-1990 was a survey of the nation’s housing

that estimated that 6 percent of U.S. homes (5.8 million in 1990)

had an annual average radon level greater than 4 picocuries per liter

(pCi/L) in indoor air. Data viability is limited given its age and 

subsequent changes as a result of education efforts and new 

housing stock.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. National Residential Radon

Survey: Summary Report, EPA 402-R-92-011. Washington, DC: EPA,

Office of Air and Radiation, October 1992. 

Web site: Report is not available online.

Indicator name: Percentage of homes where young children are

exposed to environmental tobacco smoke

Indicator type (status or trend): Status

Indicator category (1 and 2): 2

Associated question: What is the quality of the air in buildings in

the United States?

Spatial coverage: National

Temporal coverage: The National Center for Health Statistics

(NCHS), National Health Interview Survey (NHIS) has been conducted continuously since 1957, the content of the survey has been

updated about every 10-15 years. In 1996 a substantially revised

NHIS content began field testing. This new questionnaire, described

in detail below, began in 1997 and improves the ability of the NHIS

to provide important health information. 1998 data is cited.

Characterization of supporting data set(s): The NHIS is a

continuous nationwide survey in which data are collected through

personal household interviews. Self-reported information is obtained

on personal and demographic characteristics, illnesses, injuries,

impairments, chronic conditions, utilization of health resources, and

other health topics. The sample scheduled for each week is

representative of the target population, and the weekly samples are

additive over time. Response rates for special health topics

(supplements) have generally been lower. Because of the extensive

redesign of the questionnaire in 1997 and introduction of the

computer-assisted personal interviewing (CAPI) method of data

collection, data from 1997 and later years may not be comparable

with earlier years. The indicator numerator was the number of

children 6 years and under living in households with a resident who

smoked inside the home 4 or more days each week. The

denominator was the number of households with children ages 6

years and under.

Indicator source (project, program, organization, report): U.S.

Department of Health and Human Services, National Center for

Health Statistics. Healthy People 2000 Final Review, DHHS Publication

No. 01-0256. Hyattsville, MD: Public Health Service, October 2001.

Web site: http://www.cdc.gov/nchs/data/hp2000/hp2k01.pdf

Stratospheric Ozone

Indicator name: Ozone levels over North America

Indicator type (status or trend): Status (two separate data points,

not a trend)

Indicator category (1 and 2): 1

Associated question: What is the trends in the Earth’s ozone layer?

Spatial coverage: Daily images of North America. 

Temporal coverage: Begun in 1978, ongoing with a gap in coverage

from December 1994 through June 1996.

Characterization of supporting data set(s): High-resolution spectrographic images taken daily from National Aeronautics and Space

Administration (NASA) satellite platforms.

Indicator derivation (project, program, organization, report):

National Aeronautics and Space Administration. Ozone Levels Over

North America - NIMBUS-7/TOMS. March 1979 and March 1994.

(January 24, 2003; http://epa.gov/ozone/science/glob_dep.html). 

Web site: The graphic images referenced by the indicator can be

found at http://www.epa.gov.ozone/science/glob_dep.html

Indicator name: Worldwide and U.S. production of ozone-depleting

substances 

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are causing changes to the ozone layer?

Spatial coverage: Global and national

Temporal coverage: Worldwide1986 and 1999; U.S.1958-1993

Characterization of supporting data set(s): Global—The present

report contains additional and updated data on the production and

consumption of ozone-depleting substances (ODS), as reported to

the United Nations Secretariat during the period 1986-2000, by

167 of the 183 parties to the Montreal Protocol on Substances that
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-8 Indicator Metadata Appendix B

Deplete the Ozone Layer. The Secretariat has arranged the data

provided by the Parties into the groups for which control measures

are prescribed in the protocol. To calculate the figures for each

group, the quantities in metric tons reported by the parties for

each substance of the group were multiplied by the ozonedepleting potential (ODP) of that substance and added together.

All the data in this report is therefore presented in ODP tons.

National–Methodology uncertain.

Indicator derivation (project, program, organization, report):

Global: United Nations Environment Programme. Production and

Consumption of Ozone Depleting Substances under the Montreal

Protocol 1986-2000, Nairobi, Kenya: United Nations Environment

Programme, Secretariat for The Vienna Convention for the

Protection of the Ozone Layer and The Montreal Protocol on

Substances that Deplete the Ozone Layer, April 2002. National:

Historical data (1958-1993) is drawn from the report U.S.

International Trade Commission. 1993. Synthetic Organic Chemicals;

U.S. Production and Sales, Washington DC: Government Printing

Office, 1994.

Web site: EPA report http://www.epa.gov/globalwarming/

publications/emissions/index.html;

U.S. ITC report http://www.epa.gov/ozone/science/

indicat/index.html

Indicator name: Concentrations of ozone-depleting substances

(equivalent effective chlorine)

Indicator type (status or trend): Trend

Indicator category (1 and 2): 2

Associated question: What are causing changes to the ozone layer?

Spatial coverage: Global

Temporal coverage: 1992-2002

Characterization of supporting data set(s): Approximately 250

scientists from many countries of the developed and developing

world participated in the 2002 assessment as lead authors, coauthors, contributors, and reviewers.

Indicator derivation (project, program, organization, report): 

1) Scientific Assessment Panel of the Montreal Protocol on

Substances that Deplete the Ozone Layer. Scientific Assessment of

Ozone Depletion: 2002, Executive Summary, Report No. 47. Geneva,

Switzerland: World Meteorological Organization, Global Ozone

Research and Monitoring Project, 2003. 2) Montzka, S.A., J.H. Butler,

J.W. Elkins, T.M. Thompson, A.D. Clarke, and L.T. Lock. Present and

future trends in the atmospheric burden of ozone- depleting halogens. Nature 398: 690-694 (1999). 3) National Oceanic and

Atmospheric Administration, Climate Monitoring & Diagnostics

Laboratory. Halocarbons and other Atmospheric Trace Species

(HATS). 2002. March 18, 2003;

http://www.cmdl.noaa.gov/hats/graphs/graphs.html).

Web site: WMO report http://www.unep.ch/ozone/sap2002.shtml;

Global Equivalent Effective Chlorine graphic

http://www.cmdl.noaa.gov/hats/graphs/graphs
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-9

Chapter 2: Purer Water

Waters and Watersheds

Indicator name: Altered fresh water ecosystems

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of fresh surface waters

and watersheds in the U.S.?

Spatial coverage: Lower 48 states. Applies to rivers, streams, lakes,

ponds and reservoirs, and does not account for all types of alteration.

Temporal coverage: 1992 

Characterization of supporting data set(s): 1) The U.S.

Geological Survey’s National Hydrography Dataset (NHD) and the

Multi-Resolution Land Characterization (MRLC) Consortium’s

National Land Cover Database (NLCD) were used to identify alteration. NLCD uses remote-sensed image data. 2) Data on altered wetlands are available through the U.S. Fish and Wildlife Service’s

(USFWS) National Wetlands Inventory (NWI). NWI counts all wetlands, lakes, reservoirs, and ponds regardless of land ownership, but

recognizes only wetlands that are at least 3 acres, and ponds that

are at least 1 acre. At present, these data are not available in electronic form for the entire U.S.

Indicator derivation (project, program, organization, report):

1) MRLC Consortium’s NLCD and the USGS’s NHD, processed by

U.S. Environmental Protection Agency’s Office of Research and

Development, National Exposure Research Laboratory, Environmental

Sciences Division plus the 2) USFWS’s NWI. Presented in The State

of the Nation’s Ecosystems, pages 140 and 247 (The Heinz Center,

2002).

Web site: NHD http://nhd.usgs.gov/; 

NLCD http://www.epa.gov/mrlc/about.html; 

NWI http://www.nwi.fws.gov

Indicator name: Lake Trophic State Index

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of fresh surface waters

and watersheds in the U.S.?

Spatial coverage: Northeast United States

Temporal coverage: 1991-1994

Characterization of supporting data set(s): The EPA

Environmental Monitoring and Assessment (EMAP) program conducted variable probability sampling on 344 lakes throughout the

northeastern United States. The EMAP trophic state characterization

is based primarily on the total phosphorus indicator. Descriptions of

total nitrogen, chlorophyll-a, total suspended solids, and Secchi disk

transparency were used to support the total phosphorus characterization.

Indicator derivation (project, program, organization, report):

Peterson, Spencer A., David P. Larsen, Steven G. Paulsen, and N. Scott

Urquhart. Regional Lake Trophic Patterns in the Northeastern United

States: Three Approaches. Environmental Management 22 (5): 

789-801 (1999).

Web site: Full article not available on noncommercial website.

Indicator name: Wetland extent and change

Indicator type (status or trend): Status and trends

Indicator category (1 or 2): 1

Associated question: What is the extent and condition of wetlands?

Spatial coverage: Lower 48 states

Temporal coverage: 1950s to 1997 (1954-1974, 1974-1983,

1986-1997)

Characterization of supporting data set(s): An interagency group

of statisticians developed the design for the U.S. Fish and Wildlife

Service’s (USFWS) national status and trends study. The basic sampling design and study objectives have remained constant for each

wetland status and trends report. The study design consists of

4,375 randomly selected sample plots (4-square-miles in area) that

are examined and characterized using aerial imagery provided by the

National Aerial Photography Program in combination with field verification to determine wetland change. Estimates of change in wetlands

were made over a specific time period. To make the three studies

used comparable, the USFWS authors of the 2000 report adjusted

the estimate of wetland area for the mid-1980s in the 1991 report

to be in the same statistical range. Other factors contributing to this

adjustment were corrections to the wetland data set, and improved

data capture and measurement techniques (Dahl, 2000).

Indicator derivation (project, program, organization, report):

1) Dahl, T.E. Status and Trends of Wetlands in the Conterminous United

States 1986 to 1997, Washington DC: U.S. Department of the

Interior, U.S. Fish and Wildlife Service, 2000. 2) Frayer, W.E., T.J.

Monahan, D.C. Bowden, and F.A. Graybill. Status and Trends of

Wetlands and Deepwater Habitats in the Conterminous United States,

1950’s to 1970’s, Ft. Collins, CO: Colorado State University, 1983. 

3) Dahl, T.E., and C.E. Johnson. Status and Trends of Wetlands in the

Conterminous United States, Mid-1970’s to Mid-1980’s, Washington

DC: U.S. Department of the Interior, U.S. Fish and Wildlife 

Service, 1991.
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-10 Indicator Metadata Appendix B

Web site: Dahl, 2000

http://wetlands.fws.gov/bha/SandT/SandTReport.html

Indicator name: Sources of wetland change/loss

Indicator type (status or trend): Status and trend

Indicator category (1 or 2): 2

Associated question: What is the extent and condition of wetlands?

Spatial coverage: Non-federal lands, lower 48 states, Puerto Rico

and the Virgin Islands

Temporal coverage: U.S. Department of Agriculture (USDA),

National Resources Inventory (NRI) data are collected every five

years, 1982-1997.

Characterization of supporting data set(s): Data collected for the

1997 NRI were based on a statistical design to sample 800,000

sample points, using photo-interpretation and other remote sensing

methods and standards. Data gatherers utilized a variety of ancillary

materials; extensive use was made of USDA field office records, information provided by local Natural Resources Conservation Service

(NRCS) field personnel, soil survey and wetland inventory maps and

reports, and tables and technical guides developed by local field

office staffs.

Indicator derivation (project, program, organization, report):

U.S. Department of Agriculture. Summary Report: 1997 National

Resources Inventory (Revised December 2000), Washington, DC:

Natural Resources Conservation Service and Ames, Iowa: Iowa State

University, Statistical Laboratory, 2000.

Web site:

http://www.nrcs.usda.gov/technical/NRI/1997/summary_report/

table16.html

Indicator name: Water clarity in coastal waters 

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of coastal waters?

Spatial coverage: U.S. east coast south of Cape Cod, Gulf of

Mexico, and west coast.

Temporal coverage: 1990-1997 variable by region

Characterization of supporting data set(s): Data collected using a

statistically based random design from estuaries by transmissometer

at 1 meter below the water surface.

Geographic location/applicability: U.S. east coast south of Cape

Cod, Gulf of Mexico, and west coast

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency (EPA) Environmental

Monitoring and Assessment Program (EMAP) Estuaries database as

presented in U.S. Environmental Protection Agency. National Coastal

Condition Report, EPA 620-R-01-005. Washington DC: U.S.

Environmental Protection Agency, Office of Research and

Development and Office of Water, September 2001.

Web site: EMAP data

http://www.epa.gov/emap/html/dataI/estuary/data/index.html;

NCCR http://epa.gov/owow/oceans/nccr/downloads.html

Indicator name: Dissolved oxygen in coastal waters

Indicator type (status or trend): Status 

Indicator category (1 or 2): 2

Associated question: What is the condition of coastal waters?

Spatial coverage: U.S. east coast south of Cape Cod, Gulf of

Mexico, and west coast

Temporal coverage: 1990-1997 variable by region

Characterization of supporting data set(s): Data collected using a

statistically-based random design from estuaries by point-in-time or

continuously recording dissolved oxygen meter a 1 meter above the

bottom.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency (EPA) Environmental

Monitoring and Assessment Program (EMAP) Estuaries database as

presented in U.S. Environmental Protection Agency. National Coastal

Condition Report, EPA 620-R-01-005. Washington DC: EPA, Office of

Research and Development and Office of Water, September 2001. 

Web site: EMAP data 

http://www.epa.gov/emap/html/dataI/estuary/data/index.html;

NCCR http://epa.gov/owow/oceans/nccr/downloads.html

Indicator name: Total organic carbon in sediments

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of coastal waters?

Spatial coverage: Mid-Atlantic estuaries 

Temporal coverage: 1997-1998

Characterization of supporting data set(s): The EPA Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Summary Database contains

water quality, sediment, benthic community, and fish data collected

by several partners in MAIA Region estuaries in 1997 and 1998. The

MAIA program conducted regular fish surveys during the summer of

1998 to characterize the structure and health of the fish communi-
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-11

ties. The stations sampled were selected according to a probabilistic

design. These stations were not identical with the stat ons sampled

for water and sediment quality analyses conducted primarily in 1997;

therefore, it is not possible to directly compare these different

analyses station by station. However, it is statisticallyvalid to 

compare results among classes of estuaries, (e.g., large versus small

estuaries, Delaware Estuary versus Chesapeake Estuary).

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. Mid- Atlantic Integrated Assessment,

MAIA - Estuaries 1997-98, Summary Report, EPA 620-R-02-003.

Narragansett, RI: EPA, Office of Research and Development, Atlantic

Ecology Division, May 2003.

Web site: MAIA Estuaries data

http://www.epa.gov/emap/maia/html/data/estuary/9798/xport.html

Indicator name: Chlorophyll concentrations

Indicator type (status or trend): Trend

Indicator category: 2

Associated question: What is the condition of coastal waters?

Spatial coverage: National in scope, selected ocean regions

Temporal coverage: 1998-2000

Characterization of supporting data set(s): Data from the

National Aeronautical and Space Administration’s (NASA) Sea

viewing Wide Field-of-view Sensor (Sea WiFS) were analyzed for

nine ocean regions by the National Ocean Service (NOS),

National Oceanographic and Atmospheric Administration (NOAA).

Reflectance, or light reflected from the sea surface is used to 

estimate chlorophyll concentrations at the surface using a series

of assumptions accepted by the scientific community (The 

Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

NASA Sea WiFS data analyzed by the NOS. Presented in The State of

the Nation’s Ecosystems, pages 80 and 226 (The Heinz Center,

2002).

Web site: http://seawifs.gsfc.nasa.gov

Indicator name: Percent urban land cover in riparian areas

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National, excluding Alaska

Temporal coverage: NLCD, 1992 imagery; C-CAP, mid-1990s

imagery; NHD, 1999.

Characterization of supporting data set(s): Riparian zones defined

as 30-meter buffer around streams, extent and locations extracted

from the National Hydrography Dataset (NHD). Urban land cover

defined as sum of low-intensity residential, high-intensity residential,

and commercial/industrial/transportation land cover types in

National Land Cover Database (NLCD) and sum of high-intensity

developed and low- intensity developed land cover types in the

Coastal Change Analysis Program (C-CAP). Cover identified by aerial

imagery.

Indicator derivation (project, program, organization, report):

NHD, NLCD, and C-CAP data processed by the U.S. Environmental

Protection Agency, Office of Research and Development, National

Exposure Research Laboratory, Environmental Sciences Division. 

Web sites: NLCD http://www.epa.gov/mrlc/about.html; 

C-CAP http://www.csc.noaa.gov/crs/lca/index.html; 

NHD http://nhd.usgs.gov/index.html; 

HUC http://water.usgs.gov/GIS/huc.html

Indicator name: Agricultural lands in riparian areas

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National, excluding Alaska

Temporal coverage: NLCD, 1992 imagery; C-CAP, mid-1990s

imagery; NHD, 1999.

Characterization of supporting data set(s): Riparian zones

defined as 30-meter buffer around streams, extent and locations

extracted from the National Hydrography Dataset (NHD). Total

agriculture is defined as the sum of row crops and pasture land

cover types in the National Land Cover Database (NLCD) and as

the amount of cultivated land in the Coastal Change Analysis

Program (C-CAP). Cover identified by aerial imagery.

Indicator derivation (project, program, organization, report):

NHD, NLCD, and C-CAP data processed by U.S. EPA National

Exposure Research Laboratory, Environmental Sciences Division. 

Web sites: NLCD http://www.epa.gov/mrlc/about.html; 

C-CAP http://www.csc.noaa.gov/crs/lca/index.html; 

NHD http://nhd.usgs.gov/index.html;

HUC http://water.usgs.gov/GIS/huc.html

Indicator name: Population density in coastal areas

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-12 Indicator Metadata Appendix B

Temporal coverage: 1790 to 1994 population data

Characterization of supporting data set(s): Various Bureau of the

Census publications were used in preparing the article. NPA Data

Services, Inc. provided the population projection data for this paper.

The Bureau of the Census, U.S. Department of the Interior, provided

historical information on coastal counties.

Indicator source (project, program, organization, report):

Culliton, Thomas J. “Population: Distribution, Density and Growth.”

In NOAA’s State of the Coast Report. Silver Spring, MD: National

Oceanic and Atmospheric Administration. 1998. (February 2003;

http://state-of- coast.noaa.gov/bulletins/html/pop_01/pop.html).

Web site: http://state-of-coast.noaa.gov/bulletins/

html/pop_01/pop.html

Indicator name: Changing stream flows

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are pressures to water quality?

Spatial coverage: National

Temporal coverage: Since end of the 19th century focusing on

period from 1970s to 1990s

Characterization of supporting data set(s): Data are from the U.S.

Geological Survey (USGS) stream gauge network using standard

USGS protocols. Data are available in the form of daily streamflow

values reported as the average volume of water per second over a

24-hour period. Gauge placement by the USGS is not a random

process as gauges are generally placed on larger, perennial streams

and rivers, and changes seen in these larger systems may differ from

those seen in smaller streams and rivers (The Heinz Center, 2002).

Indicator source (project, program, organization, report): USGS

stream gauging network. Presented in The State of the Nation’s

Ecosystems, pages 142 and 249 (The Heinz Center, 2002).

Web site: http://www.water.usgs.gov.nwis.discharge

Indicator name: Number/duration of dry stream flow periods in

grassland/shrublands

Indicator type (status or trend): Trend

Indicator category: 2

Associated question: What are pressures to water quality?

Spatial coverage: National

Temporal coverage: 1950s to 1990s

Characterization of supporting data set(s): Data are from the U.S.

Geological Survey (USGS) stream gauge network using standard

USGS protocols. Data are available in the form of daily streamflow

values reported as the average volume of water per second over a

24-hour period. Gauge placement by the USGS is not a random

process as gauges are generally placed on larger, perennial streams

and rivers, and changes seen in these larger systems may differ from

those seen in smaller streams and rivers (The Heinz Center, 2002).

The number of sites with at least one no-flow day in a year was

determined for each water year from 1950 to 1999. The corresponding percentage value for that year was also calculated as 100 x

(number of sites/total sites). The percentage values were then averaged over each decade (i.e., 1950s, 1960s, 1970s, 1980s, and

1990s). This procedure was followed for all sites with greater than

50% grassland/shrubland cover as well as for each ecoregion 

(The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS stream gauge network. Presented in The State of the Nation’s

Ecosystems, pages 166 and 259 (The Heinz Center, 2002).

Web site: http://water.usgs.gov/nwis/discharge 

Indicator name: Sedimentation index

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Statistically selected stream sites in the MidAtlantic states (parts of Virginia, Maryland, Pennsylvania, and New

York and all of West Virginia) 

Temporal coverage: 1993-1994 sampling years

Characterization of supporting data set(s): About 450 stream

reaches were sampled in the Mid-Atlantic Highlands. To describe the

condition of all streams within the Highlands without sampling all of

them EMAP worked with EPA Region 3 and the states to develop a

regional statistical survey of streams. A sedimentation index was

developed for streams in the Mid-Atlantic Highlands to assess the

quality of instream habitat to support aquatic communities. Stream

sedimentation was defined as an increase or excess in the amount of

fine substrate particles (smaller than 16mm diameter) relative to an

expected reference value that is based on the region and the 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. Mid-Atlantic Highlands Streams

Assessment, EPA 903-R-00-015. Philadelphia, PA: U.S. Environmental

Protection Agency Region 3, Office of Research and Development,

August 2000.

Web site: MAIA Report http://www.epa.gov/maia/html/maha.html

Indicator name: Atmospheric deposition of nitrogen

Indicator type (status or trend): Status and trend
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-13

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: NADP/NTN consists of over 250 sites in the continental U.S., Alaska, Puerto Rico, and the Virgin Islands. 

Temporal coverage: 2001

Characterization of supporting data set(s): 1) The data is collected by uniform methods/protocol under the National Atmospheric

Deposition Program (NADP)/National Trends Network (NTN) and

the Clean Air Status and Trends Network (CASTNet). The NADP is a

cooperative program among federal and state agencies, universities,

electric utilities, and other industries that has measured precipitation

chemistry in the U.S. since 1978. The NADP/NTN is a nationwide

network of precipitation monitoring sites designed to measure

regional levels of atmospheric deposition. The NADP/NTN measures

wet acid deposition that occurs in rain, snow, or sleet) weekly at

about 250 monitoring stations throughout the U.S. The data are

subject to strict quality assurance and completeness screening in 

the field, in the laboratory, and during analysis. 2) CASTNet is a

nationwide network of over 70 sites concentrated in the eastern 

continental U.S. that measure ambient air concentrations of pollutants. CASTNet has not yet completed its expansion into the Great

Plains and western states. CASTNet also measures dry deposition

(the process through which particles and gases are deposited in the

absence of precipitation) of acidic compounds. CASTNet data are

also subject to strict quality assurance and completeness criteria

(EPA, OAR, November 2002).

Indicator derivation (project, program, organization, report):

NADP/NTN and CASTNet

Web site:

http://nadp.sws.uiuc.edu/isopleths/maps2001/no3dep.pdf and

http://nadp.sws.uiuc.edu/isopleths/maps2001/nh4dep.pdf 

Indicator name: Nitrate in farmland, forested, and urban streams

and ground water

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National. Major river basins and watersheds

across U.S.

Temporal coverage: 1992-1998

Characterization of supporting data set(s): Nitrate data were collected annually from 105 stream sites and 1,190 wells in agricultural

areas from 36 major river basins in the conterminous U.S. 1992-

1998. The U.S. Geological Survey’s (USGS) National Water Quality

Assessment (NAWQA) program samples watersheds with relatively

homogeneous land use/land cover to better illuminate the effect of

land use on water quality. All sample were collected and analyzed by

USGS according to the overall NAWQA design. The data are highly

aggregated and should be interpreted mainly as an indication of 

general national patterns (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NAWQA. Presented in The State of the Nation’s Ecosystems,

pages 95 and 232 (The Heinz Center, 2002)

Web site: http://water.usgs.gov/nawqa

Indicator name: Total nitrogen in coastal waters

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Mid-Atlantic estuaries 

Temporal coverage: 1997-1998

Characterization of supporting data set(s): The EPA Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Summary Database contains

water quality, sediment, benthic community, and fish data collected

by several partners in MAIA Region estuaries in 1997 and 1998. The

MAIA program conducted regular fish surveys during the summer of

1998 to characterize the structure and health of the fish communities. The stations sampled were selected according to a probabilistic

design. These stations were not identical with the stat ons sampled

for water and sediment quality analyses conducted primarily in 1997;

therefore, it is not possible to directly compare these different

analyses station by station. However, it is statistically valid to 

compare results among classes of estuaries, (e.g., large versus small

estuaries, Delaware Estuary versus Chesapeake Estuary).

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. Mid- Atlantic Integrated Assessment,

MAIA - Estuaries 1997-98, Summary Report, EPA 620-R-02-003.

Narragansett, RI: U.S. Environmental Protection Agency, Office of

Research and Development, Atlantic Ecology Division, May 2003.

Web site: MAIA Estuaries data

http://www.epa.gov/emap/maia/html/data/estuary/9798/xport.html

Indicator name: Phosphorus in farmland, forested, and urban

streams

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National. Major river basins and watersheds

across U.S.

Temporal coverage: 1992-1998
B-14 Indicator Metadata Appendix B

Characterization of supporting data set(s): Phosphorus data were

collected annually from 105 stream sites in agricultural areas from 36

major river basins in the conterminous U.S. 1992-1998. The U.S.

Geological Survey’s (USGS) National Water Quality Assessment

(NAWQA) program samples watersheds with relatively homogeneous

land use/land cover to better illuminate the effect of land use on

water quality. All sample were collected and analyzed by USGS

according to the overall NAWQA design. The data are highly aggregated and should be interpreted mainly as an indication of general

national patterns (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NAWQA. Presented in The State of the Nation’s Ecosystems,

pages 96 and 232 (The Heinz Center, 2002)

Web site: http://water.usgs.gov/nawqa

Indicator name: Phosphorus in large rivers

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National. Major river basins and watersheds

across U.S.

Temporal coverage: 1992-1998

Characterization of supporting data set(s): Phosphorus data

were collected annually from 140 stream sites in agricultural areas

from 36 major river basins in the conterminous U.S. 1992-1998.

The U.S. Geological Survey’s (USGS) National Water Quality

Assessment (NAWQA) and National Stream Water Quality

Accounting Network (NASQAN) program sampling efforts from

1992 to 1998. NAWQA samples watersheds with relatively homogeneous land use/land cover to better illuminate the effect of land use

on water quality. All sample were collected and analyzed by USGS

according to the overall NAWQA design. The data are highly aggregated and should be interpreted mainly as an indication of general

national patterns (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NAWQA. Presented in , pages 141 and 248 (The Heinz

Center, 2002)

Web site: http://water.usgs.gov/nawqa

Indicator name: Total phosphorus in coastal waters

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Mid-Atlantic estuaries 

Temporal coverage: 1997-1998

Characterization of supporting data set(s): The EPA Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Summary Database contains

water quality, sediment, benthic community, and fish data collected

by several partners in MAIA Region estuaries in 1997 and 1998. The

MAIA program conducted regular fish surveys during the summer of

1998 to characterize the structure and health of the fish communities. The stations sampled were selected according to a probabilistic

design. These stations were not identical with the stat ons sampled

for water and sediment quality analyses conducted primarily in 1997;

therefore, it is not possible to directly compare these different

analyses station by station. However, it is statistically valid to compare results among classes of estuaries, (e.g., large versus small estuaries, Delaware Estuary versus Chesapeake Estuary).

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. Mid-Atlantic Integrated Assessment,

MAIA-Estuaries 1997-98, Summary Report, EPA 620-R-02-003.

Narragansett, RI: EPA, Office of Research and Development, Atlantic

Ecology Division, May 2003.

Web site: MAIA Estuaries data

http://www.epa.gov/emap/maia/html/data/estuary/9798/xport.html

Indicator name: Atmospheric deposition of mercury

Indicator type (status or trend): Status and trend

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National with limited coverage related to mercury

emission sources

Temporal coverage: 2001

Characterization of supporting data set(s): The National

Atmospheric Deposition Program (NADP), Mercury Deposition

Network (MDN) is a cooperative program among federal and state

agencies, universities, electric utilities, and other industries. Samples

were collected from 50 sites across the U.S. related to mercury

emissions. The network uses standardized methods for collection

and analyses. Weekly precipitation samples are collected and analyzed by cold vapor atomic fluorescence. The MDN provides data

for total mercury, but also includes methylmercury if desired by a

site sponsor. 

Indicator derivation (project, program, organization, report):

NADP, MDN

Web site:

http://nadp.sws.uiuc.edu/mdn/maps/2001/01MDNdepo.pdf

Indicator name: Chemical contamination in streams and ground

water

Indicator type (status or trend): Status

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-15

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Lower 48 states

Temporal coverage: 1992-1998 

Characterization of supporting data set(s): The data for freshwater

streams and ground water were collected and analyzed by the U.S.

Geological Survey’s (USGS), National Water Quality Assessment

(NAWQA) in 36 major river basins and aquifers across the U.S. 

Indicator derivation (project, program, organization, report):

USGS, NAWQA. Presented in The State of the Nation’s Ecosystems,

pages 48-51 and 210 (The Heinz Center, 2002).

Web site: http://water.usgs.gov/nawqa

Indicator name: Pesticides in farmland streams and ground water

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National in scope, 20 hydrologic basins

Temporal coverage: 1992-1998

Characterization of supporting data set(s): Data collection from

1992-1996 included analyses for 76 pesticides and 7 selected

pesticide degradation products, in 8,200 samples of ground

water/surface water in 20 of the nation’s major hydrologic basins.

The U.S. Geological Survey’s (USGS) National Water Quality

Assessment (NAWQA) program samples watersheds with relatively

homogeneous land use/land cover to better illuminate the effect of

land use on water quality. All sample were collected and analyzed

by USGS according to the overall NAWQA design. The data are

highly aggregated and should be interpreted mainly as an indication of general national patterns (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NAWQA. Presented in The State of the Nation’s Ecosystems,

pages 97-98 and 234 (The Heinz Center, 2002)

Web site: http://water.usgs.gov/nawqa

Indicator name: Acid sensitivity in lakes and streams

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Eastern United States

Temporal coverage: 1984-1986

Characterization of supporting data set(s): In the mid-1980’s, 

the U.S. Environmental Protection Agency (EPA) and other federal

agencies commissioned a National Surface Water Survey (NSWS) to

examine the effect of acid deposition in over 1,000 lakes 1,000

lakes larger than 10 acres and in thousands of miles of streams

believed to be sensitive to acidification.

Indicator source (project, program, organization, report): 1)

EPA, NSWS and 2) Baker, L.A., A. Herlihy, P. Kaufmann, and J. Eilers.

Acid Lakes and Streams in the United States: the role of acid 

deposition. Science 252:1151-1154 (1991).

Web site: NSWS not available online and Baker, et al., not available

on a noncommercial website.

Indicator name: Toxic releases to water of mercury, dioxin, lead,

PCBs, and PBTs

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National

Temporal coverage: 2000

Characterization of supporting data set(s): The U.S.

Environmental Protection Agency (EPA) Toxics Release Inventory

(TRI) database consists of release and other waste management

information from facilities. EPA requires facilities to use one or

more of four general approaches to estimating/measuring releases,

namely, monitoring, emission factors, mass balance, and 

engineering calculations. Facilities report release and other waste

management information along with information about release

estimation methods. 

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. 2000 Toxics Release Inventory Public

Data Release Report, EPA 260-S-02-001. Washington, DC: U.S.

Environmental Protection Agency, Office of Environmental

Information, May 2002.

Web site: http://www.epa.gov/tri/

Indicator name: Sediment contamination of inland waters

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: National, generally from sites targeted for contamination problems

Temporal coverage: 1980-1999
B-16 Indicator Metadata Appendix B

Characterization of supporting data set(s): Data are contained in

the U.S. Environmental Protection Agency’s (EPA) National Sediment

Quality Inventory, comprehensive national survey of data about the

quality of aquatic sediments in the United States mandated by

Congress, and the forthcoming report of this data is an update of a

1997 report. The underlying data primarily are those reported to the

EPA Storage and Retrieval (STORET) database. Data are from 19,470

sites evaluated. Limitations of the compiled data include: the mixture

of data sets derived from different sampling strategies; incomplete

sampling coverage; the age and quality of the data; and missing

information, such as latitude and longitude. The limitations of the

evaluation approach include uncertainties in the tools used to assess

sediment quality. Because of these limitations, the draft report

assesses locations in the U.S. where there is the probability of

adverse effects to human health and the environment. Since the data

in this report come from non-random sampling and do not cover the

entire country, EPA states that it is not appropriate to come up with

a national estimate of contaminated sediments. EPA also states that

the results from the trend assessment should not be extrapolated to

areas of the country where data were not available. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. The Incidence and Severity of

Sediment Contamination in Surface Waters of the United States,

National Sediment Quality Survey: Second Edition, DRAFT, EPA 823-R01-01. Washington, DC: EPA, Office of Water, December 2001.

Web site: http://www.epa.gov/waterscience/cs/surveyfs.html

Indicator name: Sediment contamination of coastal waters

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Eastern U.S. south of Cape Cod and Gulf of

Mexico estuaries

Temporal coverage: 1990-1997

Characterization of supporting data set(s): The data for sediments and fish contamination in coastal waters were collected and

analyzed by the U.S. Environmental Protection Agency’s (EPA)

Environmental Monitoring and Assessment Program (EMAP). The

data were collected in a manner that allows conclusions to be drawn

concerning the majority (approximately 76 percent) of the area of

estuaries in the United States. The list of contaminants targeted in

sediments by EMAP include pesticides, polychlorinated biphenyls

(PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals.

Samples collected from over 2,000 location for measurement of over

100 contaminants. Sample sites selected based upon statistically

random design.

Indicator source (project, program, organization, report): EPA’s

EMAP Estuaries data set (EPA, 2001) implemented through partnerships with the National Oceanic and Atmospheric Administration

(NOAA), the U.S. Geological Survey (USGS), coastal states, and academia as reported in U.S. Environmental Protection Agency. National

Coastal Condition Report, EPA 620-R-01-005. Washington DC: EPA,

Office of Research and Development and Office of Water, September

2001. Presented in The State of the Nation’s Ecosystems, 72 and 220

(The Heinz Center, 2002).

Web site: EMAP http://www.epa.gov/emap/; 

NCCR http://epa.gov/owow/oceans/nccr/downloads.html

Indicator name: Sediment toxicity in estuaries

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What are pressures to water quality?

Spatial coverage: Eastern U.S. south of Cape Cod and Gulf of

Mexico estuaries

Temporal coverage: 1990-1997 for EMAP and since 1986 for

NOAA

Characterization of supporting data set(s): The data were 

collected and analyzed by the U.S. Environmental Protection

Agency’s (EPA) Environmental Monitoring and Assessment Program

(EMAP) and the National Oceanic and Atmospheric Administration

(NOAA) National Status and Trends (NS&T) Program. 1) The

EMAP data from over 2,500 location were collected in a manner

that allows conclusions to be drawn concerning the majority

(approximately 76 percent) of the area of estuaries in the United

States. Sample sites selected based upon statistically random

design. 2) The NOAA NS&T bioeffects program collected toxicity

data from 22 major estuaries of the United States. 

Indicator derivation (project, program, organization, report):

EPA’s EMAP Estuaries data set (EPA, 2001) implemented in partnership with NOAA, as reported in U.S. Environmental Protection

Agency. National Coastal Condition Report, EPA 620-R-01-005.

Washington DC: U.S. Environmental Protection Agency, Office of

Research and Development and Office of Water, September 2001. 

Web site: EMAP http://www.epa.gov/emap/; 

NCCR http://epa.gov/owow/oceans/nccr/downloads.html; 

NOAA http://ccmaserver.nos.noaa.gov/NSandT/New_NSandT.html

Drinking Water

Indicator name: Population served by community water systems

that meet all health-based standards 

Indicator type (status or trend): Status and trends

Indicator category (1 or 2): 1

Associated question: What is the quality of drinking water?

Spatial coverage: National

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-17

Temporal coverage: 1993-2001

Characterization of supporting data set(s): Community water

systems report monitoring violations quarterly to the states and

data are compiled by the U.S. Environmental Protection Agency

(EPA). The over 55,000 water systems that are required to report

violations serve about 94% of the U.S. population. The Safe

Drinking Water Information System (SDWIS) contains information

about public water systems and their violations of EPA’s drinking

water regulations, as reported to EPA by states and EPA regions in

conformance with reporting requirements established by statute,

regulation and guidance. States report the following information to

EPA: 

Q Basic information on each water system, including: name, ID

number, number of people served, type of system (year-round or

seasonal), and source of water (ground water or surface water);

Q Violation information for each water system: whether it has 

followed established monitoring and reporting schedules, complied with mandated treatment techniques, or violated any

Maximum Contaminant Levels (MCLs);

Q Enforcement information: what actions states have taken to

ensure that drinking water systems return to compliance if they

are in violation of a drinking water regulation;

Q Sampling results for unregulated contaminants and for regulated

contaminants when the monitoring results exceed the MCL.

Indicator derivation (project, program, organization, report):

EPA SDWIS Federal version.

Web site: http://www.epa.gov/safewater/sdwisfed/sdwis.htm

Recreation in and on the Water

Indicator name: Number of beach days that beaches are closed or

under advisory

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of surface waters supporting recreational use?

Scale and coverage: National, coastal

Temporal coverage: 2001 reporting year, collected since 1997

Characterization of supporting data set(s): A questionnaire is

sent to managers (usually health or environmental quality departments in states, counties, or cities) responsible for monitoring swimming beaches on the coasts or estuaries of the Atlantic Ocean,

Pacific Ocean, and Gulf of Mexico, and the shoreline of the Great

Lakes; information on some inland fresh water beaches has also been

collected. Days that beaches are closed or under advisory are

extracted from the survey and compiled by the U.S. Environmental

Protection Agency (EPA). Respondents numbered 237 in 2001

reporting on 2,445 beaches.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. EPA’s Beach Watch Program:

2001 Swimming Season, EPA 823-F-02-006. Washington, DC: U.S.

Environmental Protection Agency, Office of Water, May 2002. 

Web site: http://www.epa.gov/waterscience/beaches/2001

surveyfs.pdf 

Consumption of Fish and Shellfish

Indicator name: Percent of river miles and lake acres under fish consumption advisories

Indicator type (status or trend): Status and trend

Indicator category (1 or 2): 2

Associated question: What is the condition of waters that support

consumption of fish and shellfish?

Spatial coverage: National

Temporal coverage: 1993-2001

Characterization of supporting data set(s): The National 

Listing of Fish and Wildlife Advisories (NLFWA) database includes

all available information describing state-, tribal-, and federallyissued fish consumption advisories in the United States for the 50

States, the District of Columbia, and four U.S. Territories, and in

Canada for the 12 provinces and territories. The database contains

information provided to the U.S. Environmental Protection Agency

(EPA) by the states, tribes, territories and Canada. The EPA has

compiled these advisory data into a database which lists, among

other things, species and size of fish or wildlife under advisory,

chemical contaminants covered by the advisory, location and surface area of the waterbody under advisory, and population subject

to the advisory.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. Update: National Listing of Fish

and Wildlife Advisories. EPA 823-F-02-007. Washington, DC: EPA,

Office of Water, May 2002.

Web site: http://www.epa.gov/waterscience/fish/advisories/

factsheet.pdf

Indicator name: Contaminants in fresh water fish

Indicator type (status or trend): Status 

Indicator category (1 or 2): 2

Associated question: What is the condition of waters that support

consumption of fish and shellfish?

Spatial coverage: Lower 48 states

Temporal coverage: 1992-1998 (USGS)
B-18 Indicator Metadata Appendix B

Characterization of supporting data set(s): From 1992 to 1998,

fish samples were collected and analyzed from 223 stream sites by

the U.S. Geological Survey’s (USGS) National Water Quality

Assessment (NAWQA) program. Tissue composites from whole fish

were analyzed for polychlorinated biphenyls (PCBs), organochlorine

pesticides, and trace elements. The stream sites selected were r

epresentative of a large range of stream sizes, land use practices and

were not selected to be a statistical representation of U.S. streams

(The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NAWQA; EPA, EMAP and GLNPO. Presented in The State of

the Nation’s Ecosystems, pages 48-51 and 210 (The Heinz Center,

2002).

Web site: NAWQA http://water.usgs.gov/nawqa

Indicator name: Number of watersheds exceeding health-based

national water quality criteria for mercury and PCBs in fish tissue 

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the condition of waters that support

consumption of fish and shellfish?

Spatial coverage: National; for mercury, 35 states (West coast and

eastern two-thirds of the U.S.)

Temporal coverage: 2001 reporting year, collected 1993-2001

Characterization of supporting data set(s): The data set is a compilation of fish tissue quality data housed in the U.S. Environmental

Protection Agency’s (EPA) National Listing of Fish and Wildlife

Advisories (NLFWA) fish tissue database. Mercury data represented

in 696 watersheds and PCBs in 153 watersheds. Mercury map is

based on 22,000 records of fish tissue mercury concentrations from

the NLFWA where air deposition is the sole significant source of

mercury. Watersheds are eliminated from the analysis if they contain

potentially significant, but unquantified, runoff and effluent loads

from mercury mines, large-producer gold mines, and mercury-cell

chlor-alkali facilities. Watersheds are also eliminated when the total

screening level effluent load estimates for municipal wastewater

treatment plants and pulp and paper mills are above five percent of

the estimated waterbody-delivered air deposition load (EPA, Office

of Water, November 2001).

Indicator derivation (project, program, organization, report):

EPA NLFWA Mercury Fish Tissue Database, June 2001 as presented

in U.S. Environmental Protection Agency. Mercury Maps: Linking Air

Deposition and Fish Contamination on a National Scale. EPA 823-F-01-

026. Washington, DC: EPA, Office of Water, November 2001.

Web site: Mercury map

http://www.epa.gov/waterscience/maps/factsheet.pdf

Chapter 3: Better

Protected Land

Land Use

Indicator name: Extent of developed lands

Indicator type (status or trend): Status and Trend

Indicator Category: 1

Associated question: What is the extent of developed lands?

Spatial coverage: National, statistical sample of non-federal lands.

The U.S. Department of Agriculture (USDA) Natural Resources

Conservation Service’s (NRCS) National Resources Inventory (NRI)

collects data at the same 800,000 sampling sites every five years in

all 50 states, Puerto Rico, the U.S. Virgin Islands, and some Pacific

Basin locations.

Temporal coverage: At each NRI sample point, information is 

available for 1982, 1987, 1992, and 1997 so that trends and

changes in land use and resource characteristics over 15 years can

be examined and analyzed. 

Characterization of supporting data set(s): NRI is a statistical

sampling of over 800,000 locations to collect data on land cover

and use, soil erosion, prime farmland soils, wetlands, habitat diversity,

conservation practices, and related resource attributes. NRI is a compilation of natural resource information on non-Federal land in the

U.S. 

Indicator derivation (project, program, organization, report):

U.S. Department of Agriculture. Summary Report: 1997 National

Resources Inventory (Revised December 2000), Washington, DC:

Natural Resources Conservation Service and Ames, Iowa: Iowa State

University, Statistical Laboratory, 2000.

Web site: http://www.nrcs.usda.gov/technical/NRI/

Indicator name: Extent of urban and suburban lands

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the extent of developed lands?

Spatial coverage: Lower 48 states.

Temporal coverage: 1992 satellite land cover data.

Characterization of supporting data set(s): The National Land

Cover Dataset (NLCD). In the 1990s, a federal interagency 

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Appendix B Indicator Metadata B-19

consortium (the Multi-Resolution Land Characterization (MRLC)

consortium) was created to coordinate access to and use of land

cover data from the Landsat 5 Thematic Mapper. Using Landsat data

and a variety of ancillary data, the consortium processed data from a

series of 1992 Landsat images, to create the NLCD on a square grid

covering the lower 48 states. The MRLC NLCD with 21 land cover

classes, was further processed by the USGS for the Heinz Center to

estimate the urban and suburban area coverage for the U.S. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency, Office of Research and

Development. Multi-resolution land characteristics consortium -

national land cover data. 1992. (February 19, 2003;

http://www.epa.gov/mrlc/nlcd.html). Presented in The State of the

Nation’s Ecosystems, pages 181 and 264 (The Heinz Center, 2002).

Web site: Data are available from http://www.usgs.gov/mrlcreg.html

Indicator name: Extent of agricultural land uses

Indicator type (status or trend): Status and Trend

Indicator Category: 1

Associated question: What is the extent of farmlands?

Spatial coverage: National, statistical sample of non-federal lands.

The U.S. Department of Agriculture (USDA) Natural Resources

Conservation Service’s (NRCS) National Resources Inventory (NRI)

collects data at the same 800,000 sampling sites every five years in

all 50 states, Puerto Rico, the U.S. Virgin Islands, and some Pacific

Basin locations.

Temporal coverage: At each NRI sample point, information is 

available for 1982, 1987, 1992, and 1997 so that trends and

changes in land use and resource characteristics over 15 years can

be examined and analyzed. 

Characterization of supporting data set(s): NRI is a statistical

sampling of over 800,000 locations to collect data on land cover

and use, soil erosion, prime farmland soils, wetlands, habitat diversity,

conservation practices, and related resource attributes. NRI is a 

compilation of natural resource information on non-Federal land in

the U.S. 

Indicator derivation (project, program, organization, report):

U.S. Department of Agriculture. Summary Report: 1997 National

Resources Inventory (Revised December 2000), Washington, DC:

Natural Resources Conservation Service and Ames, Iowa: Iowa State

University, Statistical Laboratory, 2000.

Web site: http://www.nrcs.usda.gov/technical/NRI/

Indicator name: The farmland landscape

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the extent of farmlands?

Spatial coverage: Lower 48 states.

Temporal coverage: 1992 satellite land cover data.

Characterization of supporting data set(s): The National 

Land Cover Dataset (NLCD). In the 1990s, a federal interagency

consortium (the Multi-Resolution Land Characterization (MRLC)

consortium) was created to coordinate access to and use of land

cover data from the Landsat 5 Thematic Mapper. Using Landsat

data and a variety of ancillary data, the consortium processed data

from a series of 1992 Landsat images, to create the NLCD on a

square grid covering the lower 48 states. The MRLC NLCD with 21

land cover classes, was aggregated and reprocessed by the USGS

for the Heinz Center to estimate the farmland landscape coverage

for the U.S. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency, Office of Research and

Development. Multi-resolution land characteristics consortium -

national land cover data. 1992. (February 19, 2003;

http://www.epa.gov/mrlc/nlcd.html). Presented in The State of the

Nation’s Ecosystems, pages 92 and 231 (The Heinz Center, 2002).

Web site: Data are available from http://www.usgs.gov/mrlcreg.html

Indicator name: Extent of grasslands and shrublands

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the extent of grasslands and 

shrublands?

Spatial coverage: The lower 48 states and Alaska.

Temporal coverage: 1992 satellite imagery

Characterization of supporting data set(s): The Multi-Resolution

Land Characterization (MRLC) Consortium’s National Land Cover

Dataset (NLCD) with 21 land cover classes, was used to estimate the

area coverage for the U.S. The NLCD is based on remotely sensed

imagery from the Landsat 5 Thematic Mapper. Data for Alaska were

estimated from a vegetation map of Alaska by Fleming (1996) based

on Advanced Very High Resolution Radiometer (AVHRR) remotesensing images with an approximate resolution of 1 km on a side

(The Heinz Center, 2002). 

Indicator derivation (project, program, organization, report):

1) U.S. Environmental Protection Agency, Office of Research and

Development. Multi-resolution land characteristics consortium -

national land cover data. 1992. (February 19, 2003;

http://www.epa.gov/mrlc/nlcd.html). 2) Flemming, M.D. A Statewide

Vegetation Map of Alaska Using a Phenological Classification of AVHRR

Data. Anchorage, AK: 1996 Alaska Surveying and Mapping

Conference, February 1996. Presented in The State of the Nation’s

Ecosystems, pages 161 and 256 (The Heinz Center, 2002).
B-20 Indicator Metadata Appendix B

Web site: Data are available from http://www.usgs.gov/mrlcreg.html

Indicator name: Extent of forest area, ownership, and management

Indicator type (status or trend): Status and Trend

Indicator Category: 1

Associated question: What is the extent of forest lands?

Spatial coverage: National

Temporal coverage: Data from late 1940s to present. Data since

1953 provided with a reliability of ± 3- 10 percent per 1 million

acres (67 percent confidence limit). FIA provides updates of 

assessment data every five years. 

Characterization of supporting data set(s): The USDA Forest

Service Forest Inventory and Analysis (FIA) program is a surveybased program that has operated since the late 1940s, collecting

information on a variety of forest characteristics. FIA has used a twophase sample (generally, double sampling for stratification) to collect

information on the nation’s forests. Phase one establishes a large

number of samples (more than 4 million, roughly every 0.6 miles).

These are selected using aerial photographs or other remote-sensing

images, which are then interpreted for various forest attributes.

Phase two establishes a subset of approximately 450,000 phase-one

points (roughly every 3 miles) for ground sampling. About 125,000

of these samples are permanently established on forest land. The

forest characteristics measured include ownership, protection status,

species composition, stand age and structure, tree growth, 

occurrences of mortality and removals, tree biomass, incidences of

pathogens, natural and human-caused disturbances, and soil 

descriptors (The Heinz Center, 2002). 

Indicator derivation (project, program, organization, report):

U.S. Department of Agriculture, U.S. Forest Service. Draft Resource

Planning Act assessment tables. August 12, 2002. (September

2003; http://www.ncrs.fs.fed.us/4801/FIADB/rpa_tabler/Draft_RPA_

2002_Forest_Resource_Tables.pdf). Presented in The State of the

Nation’s Ecosystems, pages 117 and 239 (The Heinz Center, 2002).

Web site: http://www.fia.fs.fed.us/

Indicator name: Sediment runoff potential from croplands and 

pasturelands

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What are the ecological effects associated

with land uses?

Spatial coverage: National, statistical sample of non-federal lands.

The U.S. Department of Agriculture (USDA) Natural Resources

Conservation Service’s (NRCS) National Resources Inventory (NRI)

collects data at the same 800,000 sampling sites every five years in

all 50 states, Puerto Rico, the U.S. Virgin Islands, and some Pacific

Basin locations.

Temporal coverage: At each NRI sample point, information is available for 1982, 1987, 1992, and 1997 so that trends and changes in

land use and resource characteristics over 15 years can be examined

and analyzed. NRI is a compilation of natural resource information on

non-Federal land in the U.S. 

Characterization of supporting data set(s): Data are from

USDA/NRCS STATSGO Soils Data and NRI 1997 data (adjusted in

2000). The Soil and Water Assessment Tool (SWAT) is a public

domain model actively supported by the USDA Agricultural Research

Service (ARS) at the Grassland, Soil and Water Research Laboratory

in Temple, Texas.

Indicator derivation (project, program, organization, report):

Walker, Clive. Sediment Runoff Potential, 1990-1995. Hydrologic

Unit Modeling of the United States (HUMUS) Project. Temple, TX:

Texas Agricultural Experiment Station. August 24, 1999. 

Web site: Exhibit source

http://www.epa.gov/iwi/1999sept/iv12c_usmap.html; 

NRI http://www.nrcs.usda.gov/technical/NRI/; 

SWAT http://www.brc.tamus.edu/swat/

Chemicals in the Landscape

Indicator name: Quantity and type of toxic chemicals released and

managed

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: How much and what types of toxics are

released into the environment?

Spatial coverage: National

Temporal coverage: 1998-2000

Characterization of supporting data set(s): The U.S.

Environmental Protection Agency’s (EPA) Toxics Release Inventory

(TRI) database consists of release and other waste management

information from facilities. EPA requires facilities to use one or

more of four general approaches to estimating/measuring releases,

namely, monitoring, emission factors, mass balance, and engineering calculations. Facilities report release and other waste 

management information along with information about release

estimation methods. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. 2000 Toxics Release Inventory

Public Data Release Report, EPA 260-S-02-001. Washington, DC: U.S.

Environmental Protection Agency, Office of Environmental

Information, May 2002.

Web site: http://www.epa.gov/tri/

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Appendix B Indicator Metadata B-21

Indicator name: Agricultural pesticide use

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the volume, distribution, and extent

of pesticide use?

Spatial coverage: National

Temporal coverage: 1992 and 1997

Characterization of supporting data set(s): Data are based on the

National Center for Food and Agricultural Policy (NCFAP) Pesticide

Use Database, a database of information on pesticide applications to

cropland for 220 active ingredients. 

Indicator derivation (project, program, organization, report):

Data from the NCFAP, a private, non-profit, non-advocacy research

organization, as reported in Gianessi, L.P., and M.B. Marcelli. Pesticide

Use in U.S. Crop Production. Washington D.C. November, 2000. 

Web site: http://www.ncfap.org/ncfap/nationalsummary1997.pdf

Indicator name: Fertilizer use

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: What is the volume, distribution, and extent

of fertilizer use?

Spatial coverage: National

Temporal coverage: 1960-1998

Characterization of supporting data set(s): Data in the U.S.

Department of Agriculture’s (USDA) Agricultural Resources and

Environmental Indicators Report is based on a variety of surveys, as

well as the Census of Agriculture and the Natural Resources

Inventory. 

Indicator derivation (project, program, organization, report):

Daberkow, S., H. Taylor, and W. Huang. “Agricultural Resources and

Environmental Indicators: Nutrient Use and Management.”

September, 2000. In Agricultural Resources and Environmental

Indicators, Agricultural Handbook No. AH722. U.S. Department of

Agriculture, Economic Research Service, Washington, DC, February

2003, 4.4.1-4.4.49.

Web site: http://www.ers.usda.gov/publications/arei/arei2001/

Indicator name: Pesticide residues in food

Indicator type (status or trend): Trend

Indicator Category: 1

Associated question: What is the potential disposition of chemicals

used on land?

Scale and coverage: National

Temporal coverage: 1997-2000

Characterization of supporting data set(s): The U.S. Department

of Agriculture’s (USDA) Pesticide Data Program (PDP) was started by

USDA in May 1991 to provide data on pesticide dietary exposure,

food consumption, and pesticide usage. PDP data are based on 

samples of approximately 50 different commodities tested for more

than 290 different pesticides. 

Indicator derivation (project, program, organization, report):

Data from U.S. Department of Agriculture, Agricultural Marketing

Service. Pesticide Data Program: Annual Summary Calendar Year 2000,

Washington, DC: U.S. Department of Agriculture, February 2002.

PDP is USDA’s program to collect data on pesticide residues in food. 

Web site: http://www.ams.usda.gov/science/pdp/

Indicator name: Potential pesticide runoff from farm fields

Indicator type (status or trend): Status

Indicator Category: 1

Associated question: What is the potential disposition of chemicals

used on land?

Spatial coverage: National, statistical sample of non-federal lands.

The U.S. Department of Agriculture (USDA) Natural Resources

Conservation Service’s (NRCS) National Resources Inventory (NRI)

collects data at the same 800,000 sampling sites every five years in

all 50 states, Puerto Rico, the U.S. Virgin Islands, and some Pacific

Basin locations.

Temporal coverage: At each NRI sample point, information is available for 1982, 1987, 1992, and 1997 so that trends and changes in

land use and resource characteristics over 15 years can be examined

and analyzed. The data used in this analysis were from 1992. 

Characterization of supporting data set(s): Using national-level

databases, a simulation was conducted of potential pesticide losses

from representative farm fields. About 170,000 Natural Resources

Inventory (NRI) sample points were treated as “representative fields.”

Thirteen crops were included in the simulation: barley, corn, cotton,

oats, peanuts, potatoes, rice, sorghum, soybeans, sugar beets, sunflowers, tobacco, and wheat. The potential for pesticide loss from

each “representative field” was estimated using the state average

pesticide application rate and percent acres treated from the

National Pesticide Use Database. The maximum percent runoff loss

over a 20-year simulation of rainfall from the Pesticide Loss Database

was imputed to NRI sample points using match-ups by soil 

properties and proximity to 55 climate stations. The total loss of

pesticides from each “representative field” was estimated by summing

over the loss estimates for all the pesticides that the National
B-22 Indicator Metadata Appendix B

Pesticide Use Database reported for each State and crop. Watershed

scores were determined by averaging the scores for the NRI sample

points within each watershed.

Indicator derivation (project, program, organization, report):

Data are from 1)1) National Resources Inventory, U.S. Department.

of Agriculture, Natural Resources Conservation Service, 1992; 2)

National Pesticide Use Database from Gianessi, Leonard P., and James

Earl Anderson. Pesticide Use in U.S. Crop Production: National Data

Report. National Center for Food and Agricultural Policy, Washington

D.C., February 1995; and 3) Pesticide Loss Database from Don W.

Goss, Texas Agricultural Experiment Station, Temple, Texas.

Web site: http://www.epa.gov/iwi/1999sept/iv12a_usmap.html

Indicator name: Risk of nitrogen export

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the potential disposition of chemicals

used on land?

Spatial coverage: Lower 48 states

Temporal coverage: 1992 satellite imagery

Characterization of supporting data set(s): The Multi-Resolution

Land Characterization (MRLC) Consortium’s National Land Cover

Dataset (NLCD) with 21 land cover classes, was used to estimate the

area coverage for the U.S. The NLCD is based on remotely sensed

imagery from the Landsat 5 Thematic Mapper. 

Indicator derivation (project, program, organization, report):

1) U.S. Environmental Protection Agency, Office of Research and

Development. Multi-resolution land characteristics consortium -

national land cover data. 1992. (February 19, 2003;

http://www.epa.gov/mrlc/nlcd.html). 2) Wickham, J.D., K.H. Riitters,

R.V. O’Neill, K.H. Reckhow, T.G. Wade, and K.B. Jones. Land cover as

a framework for assessing risk of water pollution. Journal of the

American Water Resources Association 36 (6): 1-6 (2000).

Web site: Data are available from http://www.usgs.gov/mrlcreg.html

Indicator name: Risk of phosphorus export

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the potential disposition of chemicals

used on land?

Spatial coverage: Lower 48 states

Temporal coverage: 1992 satellite imagery

Characterization of supporting data set(s): The Multi-Resolution

Land Characterization (MRLC) Consortium’s National Land Cover

Dataset (NLCD) with 21 land cover classes, was used to estimate the

area coverage for the US. The NLCD is based on remotely sensed

imagery from the Landsat 5 Thematic Mapper. 

Indicator derivation (project, program, organization, report):

1) U.S. Environmental Protection Agency, Office of Research and

Development. Multi-resolution land characteristics consortium -

national land cover data. 1992. (February 19, 2003;

http://www.epa.gov/mrlc/nlcd.html). 2) Wickham, J.D., K.H. Riitters,

R.V. O’Neill, K.H. Reckhow, T.G. Wade, and K.B. Jones. Land cover as

a framework for assessing risk of water pollution. Journal of the

American Water Resources Association 36 (6): 1-6 (2000).

Web site: Data are available from http://www.usgs.gov/mrlcreg.html

Waste and Contaminated Lands

Indicator name: Quantity of municipal solid waste (MSW) generated and managed

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: How much and what types of waste are 

generated and managed?

Spatial coverage: National

Temporal coverage: Trends in MSW management from 1960 to

1999, including source reduction, recovery for recycling (including

composting), and disposal via combustion and landfilling.

Characterization of supporting data set(s): The supporting data

set addresses MSW in the U.S. that is generated, recycled, and 

disposed. More recently, estimates of waste prevention have been

included as well. Data are provided both for specific materials 

(glass, plastic, paper, etc.) in MSW and specific products (newspaper,

aluminum cans, etc.) in MSW.

Indicator derivation (project, program, organization, report):

Data are from U.S. Environmental Protection Agency. Municipal Solid

Waste in the United States: 2000 Facts and Figures, EPA 530-S-02-

001. U.S. Environmental Protection Agency, Office of Solid Waste

and Emergency Response, June 2002.

Web site: http://www.epa.gov/epaoswer/non-hw/muncpl/

msw99.htm

Indicator name: Quantity of RCRA hazardous waste generated 

and managed

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: How much and what types of waste are 

generated and managed?

Spatial coverage: National 

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-23

Temporal coverage: Biennial

Characterization of supporting data set(s): Generators, 

transporters, treaters, storers, and disposers of hazardous waste

are required to provide information about their activities to state

environmental agencies. These agencies in turn pass on the 

information to regional and national EPA offices. This information

is stored in EPA’s RCRAInfo database. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. The National Biennial RCRA

Hazardous Waste Report, EPA 530-R-01-009. Washington DC: U.S.

Environmental Protection Agency, Office of Solid Waste and

Emergency Response, June 2001.

Web site:

http://www.epa.gov/epaoswer/hazwaste/data/brs99/index.htm

Indicator name: Quantity of radioactive waste generated and in

inventory

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: How much and what types of waste are 

generated and managed?

Spatial coverage: National

Temporal coverage: Fiscal year 2000

Characterization of supporting data set(s): Summary data on the

amounts (volume/mass) and location of the radioactive waste, spent

nuclear fuel, and contaminated media managed by the U.S.

Department of Energy (DOE). These data are provided in a publiclyavailable report (Summary Data Report) and are based on data in

the DOE’s Environmental Management (EM) Corporate Database

(Central Internet Database). 

Indicator derivation (project, program, organization, report):

U.S. Department of Energy, Office of Environmental Management.

Central Internet Database. 2002. (January 2003;

http://cid.em.doe.gov).

Web site: http://cid.em.doe.gov

Indicator name: Number and location of municipal solid waste

(MSW) landfills

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: What is the extent of land used for waste

management?

Spatial coverage: National

Temporal coverage: Trends in MSW management from 1960 to

1999, including source reduction, recovery for recycling (including

composting), and disposal via combustion and landfilling.

Characterization of supporting data set(s): BioCycle magazine

collects the MSW landfill data annually through a survey to state

solid waste officers who relay the total number of landfills in 

each state (as reported by state agencies, counties, and/or

municipalities). There is no quality review process for these data

and there are differences in the ways data is collected and 

reported by the state programs.

Indicator derivation (project, program, organization, report):

BioCycle Journal of Composting and Organics Recycling 41 (4), April

2000 as reprinted in U.S. Environmental Protection Agency.

Municipal Solid Waste in the United States: 2000 Facts and Figures, 

EPA 530-S-02-001. U.S. Environmental Protection Agency, Office of

Solid Waste and Emergency Response, June 2002.

Web site: http://www.epa.gov/epaoswer/non-hw/

muncpl/msw99.htm 

Indicator name: Number of RCRA hazardous waste management

facilities

Indicator type (status or trend): Trend

Indicator Category: 2

Associated question: What is the extent of land used for waste

management?

Spatial coverage: National

Temporal coverage: 1999

Characterization of supporting data set(s): RCRAInfo is 

EPA’s comprehensive information system, providing access to data

supporting the Resource Conservation and Recovery Act (RCRA) of

1976 and the Hazardous and Solid Waste Amendments (HSWA) of

1984. RCRAInfo replaces the data recording and reporting abilities

of the Resource Conservation and Recovery Information System

(RCRIS) and the Biennial Reporting System (BRS). The RCRAInfo

system allows tracking of many types of information about the 

regulated universe of RCRA hazardous waste handlers. RCRAInfo

characterizes facility status, regulated activities, and compliance 

histories and captures detailed data on the generation of hazardous

waste from large quantity generators and on waste management

practices from treatment, storage, and disposal facilities. 

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency. The National Biennial RCRA

Hazardous Waste Report, EPA 530-R-01-009. Washington DC: U.S.

Environmental Protection Agency, Office of Solid Waste and

Emergency Response, June 2001. 

Web site: http://www.epa.gov/epaoswer/hazwaste/data/index.htm
B-24 Indicator Metadata Appendix B

Indicator name: Number and location of Superfund National

Priorities List sites

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: What is the extent of contaminated land?

Spatial coverage: National

Temporal coverage: 1990-2002

Characterization of supporting data set(s): CERCLIS is the

Comprehensive Environmental Response, Compensation, and 

Liability Information System. CERCLIS contains information on hazardous waste sites, potential hazardous waste sites, and remedial

activities across the nation, including sites that are on the National

Priorities List (NPL) or being considered for the NPL. CERCLIS is

used by EPA to track activities conducted under its Superfund program. Specific information is tracked for each individual Superfund

site. Sites which come to EPA’s attention because of a potential for

releasing hazardous substances into the environment are added to

the CERCLIS inventory.

Indicator derivation (project, program, organization, report):

EPA, Office of Solid Waste and Emergency Response. National

Priorities List Site Totals by Status and Milestone. March 26, 2003.

(April 3, 2003; http://www.epa.gov/superfund/sites/query/

queryhtm/npltotal.htm) and Number of NPL Site Actions and

Milestones by Fiscal Year. March 26, 2003. (April 3, 2003;

http://www.epa.gov/ superfund/sites/query/queryhtm/nplfy/htm).

Web site: http://www.epa.gov/superfund/sites/cursites/index.htm

Indicator name: Number and location of RCRA Corrective Action

Sites

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: What is the extent of contaminated land?

Spatial coverage: National

Temporal coverage: 1997-1999

Characterization of supporting data set(s): Corrective Action

(CA) is the term the Resource Conservation and Recovery Act

(RCRA) program uses to describe the cleanup of sites that 

manage hazardous wastes. The EPA Office of Solid Waste and

Emergency Response (OSWER) CA program keeps information on

CA sites in the RCRAInfo database. RCRAInfo is EPA’s comprehensive

information system, providing access to data supporting the

Resource Conservation and Recovery Act (RCRA) of 1976 and the

Hazardous and Solid Waste Amendments (HSWA) of 1984. RCRAInfo

replaces the data recording and reporting abilities of the Resource

Conservation and Recovery Information System (RCRIS) and the

Biennial Reporting System (BRS). The RCRAInfo system allows tracking of many types of information about the regulated universe of

RCRA hazardous waste handlers. RCRAInfo characterizes facility status, regulated activities, and compliance histories and captures

detailed data on the generation of hazardous waste from large quantity generators and on waste management practices from treatment,

storage, and disposal facilities. Currently, EPA believes that there are

over 6,500 facilities subject to RCRA CA statutory authorities. Of

these, approximately 3,700 facilities have CA already underway or

will need to implement CA as part of the process to obtain a permit

to treat, store, or dispose of hazardous waste. EPA refers to these

3,700 facilities as the “corrective action workload.” To help prioritize

resources further, EPA established specific short-term goals for 1,714

facilities referred to as the RCRA Cleanup Baseline.

Indicator derivation (project, program, organization, report):

U.S. Environmental Protection Agency, Office of Solid Waste and

Emergency Response. Corrective action background. October 8,

2002. (October 15, 2002; http://www.epa.gov/epaoswer/hazwaste/

ca/backgnd.htm#5).

Web site: http://www.epa.gov/epaoswer/hazwaste/ca/index.htm

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-25

Chapter 4: Human

Health

Health Status of the United States: Indicators and Trends of Health

and Disease

Indicator name: Life expectancy

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for life expectancy?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births,

deaths, marriages, and divorces in the United States. Virtually all

births and deaths are registered. U.S. Standard Live Birth and

Death Certificates are revised periodically. Most state certificates

conform closely in content and arrangement to the standard 

certificate recommended by NCHS and all certificates contain a

minimum data set specified by NCHS. The mother provides demographic information on the birth certificate, such as race and 

ethnicity, at the time of birth. Medical and health information is

based on hospital records. Demographic information on the death

certificate is provided by the funeral director based on information

supplied by an informant. A physician, medical examiner, or coroner

provides medical certification of cause of death.

Indicator source (project, program, organization, report):

NCHS, NVSS

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Cancer mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1973-1998 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral 

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of 

cause of death.

Indicator source (project, program, organization, report):

NCHS, National Vital Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Cancer incidence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to 

provide weekly provisional information on the occurrence of diseases

defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State epidemiologists report cases of notifiable diseases to CDC, and CDC tabulates

and publishes these data in the Morbidity and Mortality Weekly Report

(MMWR) and the Summary of Notifiable Diseases, United States.

Policies for reporting notifiable disease cases can vary by disease 

or reporting jurisdiction. CSTE and CDC annually review and recommend additions or deletions to the list or nationally notifiable 

diseases based on the need to respond to emerging priorities.

However, reporting nationally notifiable diseases to CDC is voluntary.

Reporting is currently mandated by law or regulation only at the

local and state level. Therefore, the list of diseases that are considered notifiable varies slightly by state. Notifiable disease data are

useful for analyzing disease trends and determining relative disease

burdens. However, these data must be interpreted in light of 

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials responsible for disease control and public health surveillance, introduction

of new diagnostic tests, or discovery of new disease entities can
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-26 Indicator Metadata Appendix B

cause changes in disease reporting that are independent of the true

incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Cardiovascular disease mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1900-1996 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral 

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of 

cause of death.

Indicator source (project, program, organization, report):

NCHS, NVSS

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Cardiovascular disease prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National

Temporal coverage: NHANES III, 1998-1994

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a

series of surveys conducted by the Centers for Disease Control’s

(CDC) National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States population, including information about many topics, such as nutrition,

heart disease, and exposure to chemicals (CDC, 2001). The

NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and

is ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to

be harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people

in the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

NHANES III, 1999. The CDC National Report on Human Exposure to

Environmental Chemicals (often referred to as the “CDC Report

Card”) summarizes chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Chronic obstructive pulmonary disease mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1980-1998 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral 

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of 

cause of death.
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-27

Indicator source (project, program, organization, report):

NCHS, NVSS

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Asthma mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1980-1999 data displayed

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral 

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of 

cause of death.

Indicator source (project, program, organization, report):

NCHS, NVSS

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Asthma prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for cancer, cardiovascular

disease, chronic obstructive pulmonary disease and asthma?

Spatial coverage: National

Temporal coverage: NHIS has been conducted continuously since

1957, the content of the survey has been updated about every 10-

15 years. In 1996 a substantially revised NHIS content began field

testing. This new questionnaire, described in detail below, began in

1997 and improves the ability of the NHIS to provide important

health information. 1980-1996 and 1980-1999 data displayed.

Characterization of supporting data set(s): The National Health

Interview Survey (NHIS) is a continuous nationwide survey in which

data are collected through personal household interviews. Selfreported information is obtained on personal and demographic

characteristics, illnesses, injuries, impairments, chronic conditions,

utilization of health resources, and other health topics. The sample

scheduled for each week is representative of the target population,

and the weekly samples are additive over time. Response rates for

special health topics (supplements) have generally been lower.

Because of the extensive redesign of the questionnaire in 1997

and introduction of the computer-assisted personal interviewing

(CAPI) method of data collection, data from 1997 and later years

may not be comparable with earlier years.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Health

Interview Survey (NHIS)

Web site: http://www.cdc.gov/nchs/nhis.htm

Indicator name: Cholera prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to 

provide weekly provisional information on the occurrence of diseases defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State epidemiologists report cases of notifiable diseases to CDC, and CDC tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can

vary by disease or reporting jurisdiction. CSTE and CDC annually

review and recommend additions or deletions to the list or nationally notifiable diseases based on the need to respond to emerging

priorities. However, reporting nationally notifiable diseases to CDC

is voluntary. Reporting is currently mandated by law or regulation

only at the local and state level. Therefore, the list of diseases that

are considered notifiable varies slightly by state. Notifiable disease

data are useful for analyzing disease trends and determining 

relative disease burdens. However, these data must be interpreted

in light of reporting practices. The degree of completeness of data

reporting also is influenced by the diagnostic facilities available,

the control measures in effect, public awareness of a specific 

disease, and the interests, resources, and priorities of state and

local officials responsible for disease control and public health 

surveillance, introduction of new diagnostic tests, or discovery of
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-28 Indicator Metadata Appendix B

new disease entities can cause changes in disease reporting that

are independent of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Cryptosporidiosis prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of 

the National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of 

diseases defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State epidemiologists report cases of notifiable diseases to CDC, and CDC tabulates and publishes these data in the Morbidity and Mortality Weekly

Report (MMWR) and the Summary of Notifiable Diseases, United

States. Policies for reporting notifiable disease cases can vary by

disease or reporting jurisdiction. CSTE and CDC annually review

and recommend additions or deletions to the list or nationally 

notifiable diseases based on the need to respond to emerging priorities. However, reporting nationally notifiable diseases to CDC is

voluntary. Reporting is currently mandated by law or regulation only

at the local and state level. Therefore, the list of diseases that are

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance, 

introduction of new diagnostic tests, or discovery of new 

disease entities can cause changes in disease reporting that are

independent of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: E. coli 0157:H7 prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of 

the National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of 

diseases defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State epidemiologists report cases of notifiable diseases to CDC, and CDC 

tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can vary

by disease or reporting jurisdiction. CSTE and CDC annually review

and recommend additions or deletions to the list or nationally notifiable diseases based on the need to respond to emerging priorities.

However, reporting nationally notifiable diseases to CDC is voluntary. Reporting is currently mandated by law or regulation only at

the local and state level. Therefore, the list of diseases that are 

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance, 

introduction of new diagnostic tests, or discovery of new 

disease entities can cause changes in disease reporting that are

independent of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Hepatitis A prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-29

Associated question: What are the trends for gastrointestinal 

illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of diseases

defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State

epidemiologists report cases of notifiable diseases to CDC, and CDC

tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can vary

by disease or reporting jurisdiction. CSTE and CDC annually review

and recommend additions or deletions to the list or nationally

notifiable diseases based on the need to respond to emerging

priorities. However, reporting nationally notifiable diseases to CDC is

voluntary. Reporting is currently mandated by law or regulation only

at the local and state level. Therefore, the list of diseases that are

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative

disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance,

introduction of new diagnostic tests, or discovery of new disease

entities can cause changes in disease reporting that are independent

of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Salmonellosis prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal

illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of diseases

defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State

epidemiologists report cases of notifiable diseases to CDC, and CDC

tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can vary

by disease or reporting jurisdiction. CSTE and CDC annually review

and recommend additions or deletions to the list or nationally

notifiable diseases based on the need to respond to emerging

priorities. However, reporting nationally notifiable diseases to CDC is

voluntary. Reporting is currently mandated by law or regulation only

at the local and state level. Therefore, the list of diseases that are

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative

disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance,

introduction of new diagnostic tests, or discovery of new disease

entities can cause changes in disease reporting that are independent

of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Shigellosis prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of diseases

defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State

epidemiologists report cases of notifiable diseases to CDC, and CDC

tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can vary

by disease or reporting jurisdiction. CSTE and CDC annually review
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-30 Indicator Metadata Appendix B

and recommend additions or deletions to the list or nationally

notifiable diseases based on the need to respond to emerging

priorities. However, reporting nationally notifiable diseases to CDC is

voluntary. Reporting is currently mandated by law or regulation only

at the local and state level. Therefore, the list of diseases that are

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative

disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance,

introduction of new diagnostic tests, or discovery of new disease

entities can cause changes in disease reporting that are independent

of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Typhoid fever prevalence

Indicator type (status or trend): Trend 

Indicator category (1 or 2): 2

Associated question: What are the trends for gastrointestinal illnesses?

Spatial coverage: National

Temporal coverage: 1997-2001

Characterization of supporting data set(s): The purpose of the

National Notifiable Disease Surveillance System is primarily to

provide weekly provisional information on the occurrence of diseases

defined as notifiable by the Council of State and Territorial

Epidemiologists (CSTE) and annual summary data. State

epidemiologists report cases of notifiable diseases to CDC, and CDC

tabulates and publishes these data in the Morbidity and Mortality

Weekly Report (MMWR) and the Summary of Notifiable Diseases,

United States. Policies for reporting notifiable disease cases can vary

by disease or reporting jurisdiction. CSTE and CDC annually review

and recommend additions or deletions to the list or nationally

notifiable diseases based on the need to respond to emerging

priorities. However, reporting nationally notifiable diseases to CDC is

voluntary. Reporting is currently mandated by law or regulation only

at the local and state level. Therefore, the list of diseases that are

considered notifiable varies slightly by state. Notifiable disease data

are useful for analyzing disease trends and determining relative

disease burdens. However, these data must be interpreted in light of

reporting practices. The degree of completeness of data reporting

also is influenced by the diagnostic facilities available, the control

measures in effect, public awareness of a specific disease, and the

interests, resources, and priorities of state and local officials

responsible for disease control and public health surveillance,

introduction of new diagnostic tests, or discovery of new disease

entities can cause changes in disease reporting that are independent

of the true incidence of disease.

Indicator source (project, program, organization, report):

Centers for Disease Control and Prevention, Epidemiology Program

Office, National Notifiable Disease Surveillance System

Web site: Morbidity and Mortality Weekly Report

http://www.cdc.gov/mmwr/; 

Summary of Notifiable Diseases

http://www.cdc.gov/epo/dphsi/annsum/

Indicator name: Infant mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1999 data displayed

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Low birthweight incidence

Indicator type (status or trend): Trend
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-31

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s

environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1991-2000 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss/htm

Indicator name: Childhood cancer mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 1994-1998 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Childhood cancer incidence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What are the trends for children’s environmental health issues?

Spatial coverage: Eleven Standard Metropolitan Statistical Areas

(SMSAs) amounting to fourteen percent of the U.S. population.

Temporal coverage: 1973 to present; 1975-1998 data displayed.

Characterization of supporting data set(s): The Surveillance,

Epidemiology, and End Results (SEER) Program of the National

Cancer Institute is a source of information on cancer incidence and

survival in the United States. The SEER Program began on January 1,

1973. NCI contracts with 11 population-based registries that cover

eleven SMSAs (and three supplemental registries) within the United

States to provide data on all residents diagnosed with cancer during

each year and to provide current followup information on all

previously diagnosed patients. The SEER Program covers

approximately 14 percent of the U.S. population. The SEER Program

is the only comprehensive source of population-based information in

the United States that includes stage of cancer at the time of

diagnosis and survival rates within each stage.

Indicator source (project, program, organization, report):

National Institutes of Health (NIH), NCI, SEER

Web site: http://seer.cancer.gov

Indicator name: Childhood asthma mortality

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s

environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-32 Indicator Metadata Appendix B

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Childhood asthma prevalence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s

environmental health issues?

Spatial coverage: National

Temporal coverage: NHIS has been conducted continuously since

1957, the content of the survey has been updated about every 10-

15 years. In 1996 a substantially revised NHIS content began field

testing. This new questionnaire, described in detail below, began in

1997 and improves the ability of the NHIS to provide important

health information. 1980-2001 data displayed.

Characterization of supporting data set(s): The National Health

Interview Survey (NHIS) is a continuous nationwide survey in which

data are collected through personal household interviews. Selfreported information is obtained on personal and demographic

characteristics, illnesses, injuries, impairments, chronic conditions,

utilization of health resources, and other health topics. The sample

scheduled for each week is representative of the target population,

and the weekly samples are additive over time. Response rates for

special health topics (supplements) have generally been lower.

Because of the extensive redesign of the questionnaire in 1997 and

introduction of the computer-assisted personal interviewing (CAPI)

method of data collection, data from 1997 and later years may not

be comparable with earlier years.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Health

Interview Survey (NHIS)

Web site: http://www.cdc.gov/nchs/nhis.htm

Indicator name: Deaths due to birth defects

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s

environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Indicator name: Birth defect incidence

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends for children’s

environmental health issues?

Spatial coverage: National. Data are for the 50 states and the

District of Columbia, unless otherwise specified.

Temporal coverage: 1933 to present; 2000 data displayed.

Characterization of supporting data set(s): National Center for

Health Statistics (NCHS), through the National Vital Statistics

Systems (NVSS), has collected and published data on births, deaths,

marriages, and divorces in the United States. Virtually all births and

deaths are registered. U.S. Standard Live Birth and Death Certificates

are revised periodically. Most state certificates conform closely in

content and arrangement to the standard certificate recommended

by NCHS and all certificates contain a minimum data set specified by

NCHS. The mother provides demographic information on the birth

certificate, such as race and ethnicity, at the time of birth. Medical
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-33

and health information is based on hospital records. Demographic

information on the death certificate is provided by the funeral

director based on information supplied by an informant. A physician,

medical examiner, or coroner provides medical certification of cause

of death.

Indicator source (project, program, organization, report):

National Center for Health Statistics (NCHS), National Vital

Statistics Systems (NVSS)

Web site: http://www.cdc.gov/nchs/nvss.htm

Measuring Exposure to Environmental

Pollution: Indicators and Trends

Indicator name: Blood lead level

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to heavy metals?

Spatial coverage: National

Temporal coverage: NHANES 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Urine arsenic level

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What is the level of exposure to heavy metals?

Spatial coverage: NHEXAS-Region 5

Temporal coverage: 1999

Characterization of supporting data set(s): The National Human

Exposure Assessment Survey (NHEXAS) was developed by the Office

of Research and Development (ORD) of the U.S. Environmental

Protection Agency (EPA) early in the 1990s to provide critical

information about multipathway, multimedia population exposure

distribution to chemical classes. Phase 1 of NHEXAS consisted of

demonstration and scoping studies in Maryland, Phoenix, Arizona,

and EPA Region 5 using probability- based sampling designs.

Although the study was conducted in three different regions of the

U.S., it was not designed to be nationally representative. The Region

5 study was conducted in Ohio, Michigan, Illinois, Indiana,

Wisconsin, and Minnesota, and measured metals and volatile organic

chemicals (VOCs).

Indicator source (project, program, organization, report):

1) NHEXAS-Region 5; 2) National Research Council. Arsenic in

Drinking Water. Washington, DC: National Academies Press, 1999. 

Web site: NHEXAS

http://www.epa.gov/nerl/research/nhexas/nhexas.htm; 

NHEXAS data in EPA’s Human Exposure Database System

http://www.epa.gov/heds/ 

Indicator name: Blood mercury level

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to heavy metals?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-34 Indicator Metadata Appendix B

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm

Indicator name: Blood cadmium level

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to heavy metals?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Blood cotinine level

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to cotinine?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES)

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Blood volatile organic compound levels

Indicator type (status or trend):

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to volatile

organic compounds?

Spatial coverage: National

Temporal coverage: NHANES III (1988-1994)

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-35

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Urine organophosphate levels to indicate pesticides

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the level of exposure to pesticides?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Blood lead level in children

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends in exposure to environmental contaminants for children?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Blood mercury level in children

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends in exposure to environmental contaminants for children?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): The National Health

and Nutrition Examination Survey (NHANES) is comprised of a series
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-36 Indicator Metadata Appendix B

of surveys conducted by the Centers for Disease Control’s (CDC)

National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES), 1999.

The CDC National Report on Human Exposure to Environmental

Chemicals (often referred to as the “CDC Report Card”) summarizes

chemical exposure data from the 1999 NHANES. 

Web site: http://www.cdc.gov/nchs/nhanes.htm 

Indicator name: Blood cotinine level in children

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What are the trends in exposure to

environmental contaminants for children?

Spatial coverage: National

Temporal coverage: NHANES, 1999-2000

Characterization of supporting data set(s): 1) The National

Health and Nutrition Examination Survey (NHANES) is comprised of

a series of surveys conducted by the Centers for Disease Control’s

(CDC) National Center for Health Statistics (NCHS). The survey is

designed to collect data on the health of the United States

population, including information about many topics, such as

nutrition, heart disease, and exposure to chemicals (CDC, 2001).

The NHANES surveys have been performed over a number of years.

The first survey, NHANES I, took place from 1971 through 1975;

NHANES II occurred from 1976-80; NHANES III was performed in

1988 through 1994; and the current NHANES began in 1999 and is

ongoing. As part of the survey, blood and urine samples were

collected to measure the amounts of certain chemicals thought to be

harmful to people. Because of the extensive work involved with

laboratory analyses, some chemicals were measured for all people in

the survey, while other chemicals were only measured for a small

sample of people in an age group. The current NHANES IV measures

exposure for 27 chemicals for people in the U.S. In previous

NHANES, exposure had been assessed via laboratory analysis for

only three chemicals: lead, cadmium and cotinine. 

Indicator source (project, program, organization, report):

National Health and Nutrition Examination Survey (NHANES)

Web site: http://www.cdc.gov/nchs/nhanes.htm 
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-37

Chapter 5: Ecological

Condition

Forests

Indicator name: Extent of area by forest type

Indicator type (status or trend): Status

Indicator Category: 1

Associated question: What is the ecological condition of forests?

Spatial coverage: Lower 48 states

Temporal coverage: 1963-1997. Data from late 1940s to present.

Data since 1953 provided with a reliability of ± 3-10 percent per 1

million acres (67 percent confidence limit). FIA provides updates of

assessment data every five years. 

Characterization of supporting data set(s): The USDA Forest

Service Forest Inventory and Analysis (FIA) program is a surveybased program that has operated since the late 1940s, collecting

information on a variety of forest characteristics. FIA has used a twophase sample (generally, double sampling for stratification) to collect

information on the nation’s forests. Phase one establishes a large

number of samples (more than 4 million, roughly every 0.6 miles).

These are selected using aerial photographs or other remote-sensing

images, which are then interpreted for various forest attributes.

Phase two establishes a subset of approximately 450,000 phase-one

points (roughly every 3 miles) for ground sampling. About 125,000

of these samples are permanently established on forest land. The

forest characteristics measured include ownership, protection status,

species composition, stand age and structure, tree growth,

occurrences of mortality and removals, tree biomass, incidences of

pathogens, natural and human-caused disturbances, and soil

descriptors (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

Smith, W.B., J.S. Vissage, D.R. Darr, and R.M. Sheffield. Forest Statistics

of the United States, 1997, General Technical Report NC-219. St.

Paul, MN: U.S. Department of Agriculture Forest Service, North

Central Research Station, 2001. Presented in The State of the

Nation’s Ecosystems, pages 118 and 240 (The Heinz Center, 2002).

Web site: http://fia.fs.fed.us

Indicator name: Forest age class

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: National, all 50 states

Temporal coverage: 1997. Data from late 1940s to present. Data

since 1953 provided with a reliability of ± 3-10 percent per 1 million

acres (67 percent confidence limit). FIA provides updates of assessment data every five years. 

Characterization of supporting data set(s): The USDA Forest

Service Forest Inventory and Analysis (FIA) program is a surveybased program that has operated since the late 1940s, collecting

information on a variety of forest characteristics. FIA has used a twophase sample (generally, double sampling for stratification) to collect

information on the nation’s forests. Phase one establishes a large

number of samples (more than 4 million, roughly every 0.6 miles).

These are selected using aerial photographs or other remote-sensing

images, which are then interpreted for various forest attributes.

Phase two establishes a subset of approximately 450,000 phase-one

points (roughly every 3 miles) for ground sampling. About 125,000

of these samples are permanently established on forest land. The

forest characteristics measured include ownership, protection status,

species composition, stand age and structure, tree growth,

occurrences of mortality and removals, tree biomass, incidences of

pathogens, natural and human-caused disturbances, and soil

descriptors (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

Smith, W.B., J. Vissage, D. Darr, and R. Sheffield. Forest Statistics of the

United States, 1997. U.S. Department of Agriculture, U.S. Forest

Service, General Technical Report NC-219. St. Paul, MN: USDA,

Forest Service. 2001. Presented in The State of the Nation’s

Ecosystems, pages 126 and 242 (The Heinz Center, 2002).

Web site: http://fia.fs.fed.us

Indicator name: Forest pattern and fragmentation

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: Lower 48 states 

Temporal coverage: 1992 satellite imagery and data from late

1940s to present. Data since 1953 provided with a reliability of ± 3-

10 percent per 1 million acres (67 percent confidence limit). FIA

provides updates of assessment data every five years. 

Characterization of supporting data set(s): 1) The MultiResolution Land Characterization (MRLC) Consortium’s National

Land Cover Dataset (NLCD) provides a consistent, uniform, spatially

explicit description of general land cover/land use across the

continental U.S. at a 30-meter resolution. It does not contain

habitat types. 2) The USDA Forest Service Forest Inventory and

Analysis (FIA) program is a survey-based program that has operated
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-38 Indicator Metadata Appendix B

since the late 1940s, collecting information on a variety of forest

characteristics. FIA has used a two-phase sample (generally, double

sampling for stratification) to collect information on the nation’s

forests. Phase one establishes a large number of samples (more than

4 million, roughly every 0.6 miles). These are selected using aerial

photographs or other remote-sensing images, which are then

interpreted for various forest attributes. Phase two establishes a

subset of approximately 450,000 phase-one points (roughly every 3

miles) for ground sampling. About 125,000 of these samples are

permanently established on forest land. The forest characteristics

measured include ownership, protection status, species composition,

stand age and structure, tree growth, occurrences of mortality and

removals, tree biomass, incidences of pathogens, natural and humancaused disturbances, and soil descriptors (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

1)Multi-Resolution Land Characterization Consortium (MRLC) -

National Land Cover Data (NLCD); 2) Conkling, B., J. Coulston, and

M. Ambrose (eds.). Forest Health Monitoring National Technical Report

1991-1999, Asheville, NC: U.S. Department of Agriculture Forest

Service, Southern Research Station, 2002; 3) Riiters, K.H., J.D.

Wickham, R.V. O’Neill, K.B. Jones, E.R. Smith, J.W. Coulston, T.G.

Wade, and J.H. Smith. Fragmentation of Continental United States

Forests. Ecosystems 5: 815-822 (2002). Presented in The State of the

Nation’s Ecosystems, pages 120-121 and 240 (The Heinz Center,

2002).

Web sites: MRLC http://www.epa.gov/mrlc/; 

NLCD http://www.epa.gov/mrlc/nlcd.html; 

Riitters, et al. material http://www.srs.fs.usda.gov/4803/landscapes/ 

Indicator name: At-risk native forest species

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: Natural Heritage programs in all 50 states.

Temporal coverage: 2000. Data managed consistently since 1974.

Characterization of supporting data set(s): NatureServe is an

independent nonprofit organization whose research biologists

gather, review, integrate, and record available information about

species taxonomy, status, and use of different habitats or ecological

system types. They are assisted in this work by scientists in the

network of Natural Heritage programs as well as by contracted

experts for different invertebrate taxa. NatureServe staff and

collaborators assign a conservation status by using standard

Heritage ranking criteria. The Heritage ranking process considers five

major status ranks: critically imperiled (G1), imperiled (G2),

vulnerable (G3), apparently secure (G4), and demonstrably

widespread, abundant, and secure (G5). In addition, separate ranks

are assigned for species regarded as presumed extinct (GX) or

possibly extinct (GH).

Indicator derivation (project, program, organization, report):

NatureServe and its member programs in the network of Natural

Heritage programs develop and maintain information on species at

risk. Presented in The State of the Nation’s Ecosystems, pages 124 and

214 (The Heinz Center, 2002).

Web site: http://www.natureserve.org

Indicator name: Populations of representative forest species

Indicator type (status or trend): Status and Trend

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: National data for birds, 37 states for trees

Temporal coverage: 1970-2002. FIA data date from late 1940s to

present. Data since 1953 provided with a reliability of ± 3-10 percent per 1 million acres (67 percent confidence limit). FIA provides

updates of assessment data every five years. BBS was initiated in

1966.

Characterization of supporting data set(s): 1) The North American

Breeding Bird Survey (BBS) is a long-term, large-scale international

avian monitoring program intended to track the status and trends of

North American bird populations. Today there are approximately

3700 active BBS routes across the continental U.S. and Canada of

which 2900 are surveyed each year (Sauer, et al., 2001). 2) The

USDA Forest Service Forest Inventory and Analysis (FIA) program is a

survey-based program that has operated since the late 1940s, 

collecting information on a variety of forest characteristics. FIA has

used a two-phase sample (generally, double sampling for stratification) to collect information on the nation’s forests. Phase one establishes a large number of samples (more than 4 million, roughly every

0.6 miles). These are selected using aerial photographs or other

remote-sensing images, which are then interpreted for various forest

attributes. Phase two establishes a subset of approximately 450,000

phase-one points (roughly every 3 miles) for ground sampling.

About 125,000 of these samples are permanently established on

forest land. The forest characteristics measured include ownership,

protection status, species composition, stand age and structure, tree

growth, occurrences of mortality and removals, tree biomass, incidences of pathogens, natural and human-caused disturbances, and

soil descriptors (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

Bird data are from the U.S. Geological Survey’s North American

Breeding Bird Survey (BBS), and tree data are from the U.S. Forest

Service, Draft Resource Planning and Assessment Tables, August

2002. Reported in U.S. Department of Agriculture. National Report

on Sustainable Forests - 2003, Final Draft, Washington, DC: U.S.

Department of Agriculture, Forest Service, 2002. This indicator was

based on the final review draft of the Sustainable Forests report

(USDA, FS, 2002) and the website for corresponding technical support material is provided below. The final version of the report and
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-39

supporting technical material will be found at

http://www.fs.fed.us/research/sustain/.

Web site: Sustainable Forests Report

http://www.fs.fed.us/research/sustain/data.htm (Indicator 9); 

RPA tables http://www.ncrs.fs.fed.us/4801/FIADB/rpa_tabler/

Draft_RPA_2002_Forest_Resource_Tables.pdf; 

BBS http://www.mp2-pwrc.usgs.gov/bbs/

Indicator name: Forest disturbance: fire, insects, and disease

Indicator type (status or trend): Trend

Indicator Category: 1

Associated question: What is the ecological condition of forests?

Spatial coverage: National, all 50 states

Temporal coverage: 1979-2000. FIA data date from late 1940s to

present. Data since 1953 provided with a reliability of ± 3-10 percent per 1 million acres (67 percent confidence limit). FIA provides

updates of assessment data every five years. 

Characterization of supporting data set(s): The USDA Forest

Service Forest Inventory and Analysis (FIA) program is a surveybased program that has operated since the late 1940s, collecting

information on a variety of forest characteristics. FIA has used a twophase sample (generally, double sampling for stratification) to collect

information on the nation’s forests. Phase one establishes a large

number of samples (more than 4 million, roughly every 0.6 miles).

These are selected using aerial photographs or other remote-sensing

images, which are then interpreted for various forest attributes.

Phase two establishes a subset of approximately 450,000 phase-one

points (roughly every 3 miles) for ground sampling. About 125,000

of these samples are permanently established on forest land. The

forest characteristics measured include ownership, protection status,

species composition, stand age and structure, tree growth,

occurrences of mortality and removals, tree biomass, incidences of

pathogens, natural and human-caused disturbances, and soil

descriptors (The Heinz Center, 2002). Data on insects and disease

are based on a probability sample that represents unbiased

estimates of both public and private forests in the U.S. 

Indicator derivation (project, program, organization, report):

Data on fires are from 1) U.S. General Accounting Office. Western

National Forests: Nearby Communities Are Increasingly Threatened by

Catastrophic Wildfires, GAO/T-RCED-99-79. Washington, DC: U.S.

General Accounting Office, 1999 and 2) National Interagency Fire

Center. Wildland Fire Statistics. 2002. (May 2003;

http://www.nifc.gov/stats/wildlandfirestats.html).; data on insects

and disease are from Conkling, B., J. Coulston, and M. Ambrose

(eds.). Forest Health Monitoring National Technical Report 1991-1999,

Asheville, NC: U.S. Department of Agriculture Forest Service,

Southern Research Station, 2002. Presented in The State of the

Nation’s Ecosystems, pages 127 and 242 (The Heinz Center, 2002).

Web site: FHM http://www.na.fs.fed.us/spfo/fhm/index.htm; 

NIFC http://www.nifc.gov/stats/wildlandfirestats.html

Indicator name: Tree condition

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: 32 states; more than half of the South and Rocky

Mountain regions had insufficient or no data.

Temporal coverage: 1990-1999

Characterization of supporting data set(s): Available national 

data relates almost exclusively to trees, not the entire suite of forest

biota. Three metrics are used to determine tree condition: tree mortality, tree crown condition, and fire condition class. National scale

data is lacking on many components of forest ecosystems. Available

data coverages are incomplete. Fundamental research linking biological components to ecological processes is lacking (USFS, FS, 2002).

Indicator derivation (project, program, organization, report):

1) Conkling, B., J. Coulston and M. Ambrose (eds). Forest Health

Monitoring National Technical Report, 1991-1999. Asheville, NC:

USDA Forest Service, Forest Health Monitoring (FHM) Program,

Southern Research Station. 2002; 2) U.S. Department of

Agriculture. National Report on Sustainable Forests - 2003, Final Draft,

Washington, DC: U.S. Department of Agriculture, Forest Service,

2002. This indicator was based on the final review draft of the

Sustainable Forests report (USDA, FS, 2002) and the website for

corresponding technical support material is provided below. The final

version of the report and supporting technical material will be found

at http://www.fs.fed.us/research/sustain/.

Web site: FHM http://www.na.fs.fed.us/spfo/fhm/index.htm;

Sustainable Forest Report

http://www.fs.fed.us/ research/sustain/data.htm (Indicator 17)

Indicator name: Ozone injury to trees

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: 32 states

Temporal coverage: 1994-2000

Characterization of supporting data set(s): The USDA Forest

Service Forest Health Monitoring (FHM) Program collects information about ozone air quality on a network of biomonitoring plots

using ozone sensitive bioindicator plants (trees, woody shrubs, and

non-woody herb species). In 2000, there were 918 biomonitoring

sites in 32 states.
B-40 Indicator Metadata Appendix B

Indicator derivation (project, program, organization, report): 1)

Conkling, B., J. Coulston, and M. Ambrose (eds.). Forest Health

Monitoring National Technical Report 1991-1999, Asheville, NC: U.S.

Department of Agriculture Forest Service, Southern Research

Station, 2002; 2) U.S. Department of Agriculture. National Report on

Sustainable Forests - 2003, Final Draft, Washington, DC: U.S.

Department of Agriculture, Forest Service, 2002. This indicator was

based on the final review draft of the Sustainable Forests report

(USDA, FS, 2002) and the website for corresponding technical support material is provided below. The final version of the report and

supporting technical material will be found at

http://www.fs.fed.us/research/sustain/.

Web site: Sustainable Forest Report

http://www.fs.fed.us/research/sustain/data.htm (Indicator 16); 

FHM http://www.na.fs.fed.us/spfo/fhm/index.htm

Indicator name: Carbon storage

Indicator type (status or trend): Trend

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: National. Data for Alaska and Hawaii are not

included in this data series. 

Temporal coverage: 1953-1996. Volume, area, and other forest

characteristics are compiled in Smith, et al., 2001 for the years

1953, 1963, 1977, 1987, and 1997. The inventory years begin on the

first calendar day of each year. More detailed data are available in

databases for 1997 (USDA, FS, 2002).

Characterization of supporting data set(s): All carbon pools, with

the exception of soil carbon, are estimated using USDA Forest

Service Forest Inventory and Analysis (FIA) measured data or imputed data, along with inventory-to-carbon relationships, developed

with information from ecological studies (USDA, 2003). Carbon

storage is estimated by the FIA program using on-the ground measurements of tree trunk size from many forest sites and statistical

models that show the relationship between trunk size and the weight

of branches, leaves, coarse roots (>0.1 inch in diameter), and forest

floor litter. Such data are combined with estimates of forest land area

obtained from aerial photographs and satellite imagery. Forest floor

litter includes all dead organic matter above the mineral soil horizons,

including litter, humus, small twigs, and coarse woody debris (branches and logs greater than 1.0 inches in diameter lying on the forest

floor). Note that there are 1.1 English tons per metric ton. In most

international discussions, carbon storage is reported in metric tons.

Indicator derivation (project, program, organization, report):

1) Smith, W.B., J.S. Vissage, D.R. Darr, and R.M. Sheffield. Forest

Statistics of the United States, 1997, General Technical Report NC219. St. Paul, MN: U.S. Department of Agriculture Forest Service,

North Central Research Station, 2001. 2) U.S. Department of

Agriculture. National Report on Sustainable Forests - 2003, Final Draft,

Washington, DC: U.S. Department of Agriculture, Forest Service,

2002. This indicator was based on the final review draft of the

Sustainable Forests report (USDA, FS, 2002) and the website for

corresponding technical support material is provided below. The final

version of the report and supporting technical material will be found

at http://www.fs.fed.us/research/sustain/.

Web site: FIA http://fia.fs.fed.us; 

Sustainable Forests Report

http://www.fs.fed.us/research/sustain/data.htm (primarily Indicator

27 with reference to Indicators 26 and 28)

Indicator name: Soil compaction

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: 37 states (mostly east of the Mississippi, Rocky

Mountains and Pacific Coast); STATSGO data are available for the

conterminous U.S., Alaska, Hawaii, and Puerto Rico.

Temporal coverage: 1998-2000

Characterization of supporting data set(s):

1) Forest Health Monitoring (FHM) Program data collected on a representative sample of 2006 plots, a subset of the Forest Inventory

Analysis (FIA) plot network (USDA, FS, 2003). The FIA soil indicator

program is in the implementation phase and plots have not yet been

established in all states. Analysis from the program is limited in

scope. Data used for this indicator are based on visual inspection

and state soil maps. No measurements were made regarding the

intensity of compaction and physical disturbances that are not readily visible from the surface may be underreported. Compaction data

from FIA/FHM are intended only to provide a “presence/absence”

index of the occurrence of disturbed soils across the landscape

(USDA, FS, 2003). 2) State Soil Geographic Database (STATSGO)

consists of state general soil maps made by generalizing the detailed

soil survey data. The level of mapping is designed to be used for

broad planning and management uses covering state, regional, and

multi-state areas. STATSGO data are designed for use in a

Geographic Information System (GIS). The mapping scale for STATSGO map is 1:250,000 (with the exception of Alaska, which is

1:1,000,000). Each STATSGO map is linked to the Soil

Interpretations Record (SIR) attribute data base. The attribute data

base gives the proportionate extent of the component soils and

their properties for each map unit. The STATSGO map units consist

of 1 to 21 components each. The Soil Interpretations Record data

base includes over 25 physical and chemical soil properties, interpretations, and productivity. Examples of information that can be

queried from the data base are available water capacity, soil reaction,

salinity, flooding, water table, bedrock, and interpretations for engineering uses, cropland, woodland, rangeland, pastureland, wildlife,

and recreation development.

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-41

Indicator derivation (project, program, organization, report):

1) U.S. Department of Agriculture. National Report on Sustainable

Forests - 2003, Washington, DC: U.S. Department of Agriculture,

Forest Service, Forthcoming, 2003. This indicator was based on 

finalized portions of the forthcoming report referenced above that

were provided to EPA for this report. The report, including technical

support material for this indicator can be found at the website listed

below. 2) STATSGO.

Web site: Sustainable Forests Report

http://www.fs.fed.us/research/sustain/; 

STATSGO http://www.ftw.nrcs.usda.gov/stat_data.html

Indicator name: Soil erosion 

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of forests?

Spatial coverage: 37 states (mostly east of the Mississippi, Rocky

Mountains and Pacific Coast); STATSGO data are available for the

conterminous U.S., Alaska, Hawaii, and Puerto Rico.

Temporal coverage: 1998-2000

Characterization of supporting data set(s): 1) Forest Health

Monitoring (FHM) Program measured erosion rates on plots and

modeled the data using the Water Erosion Prediction Project

(WEPP). Erosion estimates are limited by model assumptions and

aggregate estimates of soil erosion often have little meaning in and

of themselves due to natural variability in soil erosion (USDA, FS,

2003). 2) State Soil Geographic Database (STATSGO) consists of

state general soil maps made by generalizing the detailed soil survey

data. The level of mapping is designed to be used for broad planning

and management uses covering state, regional, and multi-state areas.

STATSGO data are designed for use in a Geographic Information

System (GIS). The mapping scale for STATSGO map is 1:250,000

(with the exception of Alaska, which is 1:1,000,000). Each STATSGO map is linked to the Soil Interpretations Record (SIR) attribute

data base. The attribute data base gives the proportionate extent of

the component soils and their properties for each map unit. The

STATSGO map units consist of 1 to 21 components each. The Soil

Interpretations Record data base includes over 25 physical and

chemical soil properties, interpretations, and productivity. Examples

of information that can be queried from the data base are available

water capacity, soil reaction, salinity, flooding, water table, bedrock,

and interpretations for engineering uses, cropland, woodland, 

rangeland, pastureland, wildlife, and recreation development.

Indicator derivation (project, program, organization, report):

U.S. Department of Agriculture. National Report on Sustainable

Forests - 2003, Washington, DC: U.S. Department of Agriculture,

Forest Service, Forthcoming, 2003. This indicator was based on finalized portions of the forthcoming report referenced above that were

provided to EPA for this report. The report, including technical 

support material for this indicator can be found at the website listed

below. 2) STATSGO.

Web site: Sustainable Forests Report—

http://www.fs.fed.us/research/sustain/; STATSGO—

http://www.ftw.nrcs.usda.gov/stat_data.html

Indicator name: Processes beyond the range of historic variation

Indicator type (status or trend): Trend

Indicator category (1 or 2): 2

Associated question: What is the ecological condition of forests?

Spatial coverage: National

Temporal coverage: Effects during 1800-1850 (historic or baseline

time period) were compared with the 1996-2000 (current time

period) and beyond the range of recent variation (using data from

the past 20-80 years) the effects of the recent past, e.g. 1979-

1995, were compared with those during the current time period

(USDA, FS, 2002).

Characterization of supporting data set(s): Primarily anecdotal

data.

Indicator source (project, program, organization, report): U.S.

Department of Agriculture. National Report on Sustainable Forests -

2003, Final Draft, Washington, DC: U.S. Department of Agriculture,

Forest Service, 2002. This indicator was based on the final review

draft of the Sustainable Forests report (USDA, FS, 2002) and the

website for corresponding technical support material is provided

below. The final version of the report and supporting technical 

material will be found at http://www.fs.fed.us/research/sustain/.

Web site: Sustainable Forests Report—

http://www.fs.fed.us/research/sustain/data.htm (Indicator 15)

Farmlands

Indicator name: Pesticide leaching potential

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the ecological condition of farmlands?

Spatial coverage: Agricultural lands covering 5.5 million hectares in

six mid-Atlantic states 

Temporal coverage: 1994 and 1995

Characterization of supporting data set(s): EPA’s Environmental

Monitoring and Assessment Program (EMAP) used the National

Agricultural Statistics Service (NASS) probability area sampling frame

in the Mid-Atlantic region to select 122 sites in 1994 and 152 sites

in 1995. The sites were sampled during the NASS Fall Survey. Soil
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-42 Indicator Metadata Appendix B

samples and questionnaire data were collected from a random sample of 293 sites. Indicators addressed productivity, management at

the agroecosystem scale, and management for the landscape scale

on annual crop land. Crop yields were almost 30% higher than those

of the 1980s, with a mean observed to expected yield index of 1.27.

The mean soil quality index showed moderate quality for supporting

plant growth. Non-tilled sites, which were mostly hay, had greater

microbial biomass than tilled sites. Just over half of the annual crop

land was covered by rotation plans; hay fields accounted for most of

the land where one crop was grown continuously. Hay showed a

lower use of applied nitrogen than seed crops. Integrated pest management was practiced on less than 20% of annual crop land.

Twenty-seven different annual crops were grown in the region, with

hay (all types) the dominant crop. Less than 20% of the land where

pesticides were applied had high to moderately high potential for

pesticides leaching into groundwater. This information provides a

baseline for long-term monitoring of agricultural lands in the region

(Hellkamp, et al. 2000).

Indicator source (project, program, organization, report):

Hellkamp, A.S., J.M. Bay, C.L. Campbell, K.N. Easterling, D.A. Fiscus,

G.R. Hess, B.F. McQuaid, M.J. Munster, G.L. Olson, S.L. Peck, S.R.

Shafer, K. Sidik, and M.B. Tooley. Assessment of the condition of

agricultural lands in six mid-Atlantic states. Journal of Environmental

Quality 29: 79-804 (2000). 

Web site: Paper abstract—

http://oaspub.epa.gov/emap/bib.print_abstract?pub_id_in=1284

Indicator name: Soil quality index

Indicator type (status or trend): Status

Indicator category (1 or 2): 2

Associated question: What is the ecological condition of farmlands?

Spatial coverage: Mid-Atlantic states

Temporal coverage: 1994-1995

Characterization of supporting data set(s): EPA’s Environmental

Monitoring and Assessment Program (EMAP) used the National

Agricultural Statistics Service (NASS) probability area sampling frame

in the Mid-Atlantic region to select 122 sites in 1994 and 152 sites

in 1995. The sites were sampled during the NASS Fall Survey. Soil

samples and questionnaire data were collected from a random

sample of 293 sites. Indicators addressed productivity, management

at the agroecosystem scale, and management for the landscape scale

on annual crop land. Crop yields were almost 30% higher than those

of the 1980s, with a mean observed to expected yield index of 1.27.

The mean soil quality index showed moderate quality for supporting

plant growth. Non-tilled sites, which were mostly hay, had greater

microbial biomass than tilled sites. Just over half of the annual crop

land was covered by rotation plans; hay fields accounted for most of

the land where one crop was grown continuously. Hay showed a

lower use of applied nitrogen than seed crops. Integrated pest

management was practiced on less than 20% of annual crop land.

Twenty-seven different annual crops were grown in the region, with

hay (all types) the dominant crop. Less than 20% of the land where

pesticides were applied had high to moderately high potential for

pesticides leaching into groundwater. This information provides a

baseline for long-term monitoring of agricultural lands in the region

(Hellkamp, et al. 2000).

Indicator source (project, program, organization, report): Data

are available from the EPA Mid- Atlantic Integrated Assessment

(MAIA) initiative and the index is described in Hellkamp, A.S., J.M.

Bay, C.L. Campbell, K.N. Easterling, D.A. Fiscus, G.R. Hess, B.F.

McQuaid, M.J. Munster, G.L. Olson, S.L. Peck, S.R. Shafer, K. Sidik,

and M.B. Tooley. Assessment of the condition of agricultural lands in

six mid-Atlantic states. Journal of Environmental Quality 29: 79-804

(2000). 

Web site: Paper abstract

http://oaspub.epa.gov/emap/bib.print_abstract?pub_id_in=1284

Indicator name: Soil erosion

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of farmlands?

Spatial coverage: National

Temporal coverage: At each Natural Resources Inventory (NRI)

sample point, information is available for 1982, 1987, 1992, and

1997 so that trends and changes in land use and resource characteristics over 15 years can be examined and analyzed. 

Characterization of supporting data set(s): 1) The NRI is a statistical sampling of over 800,000 locations to collect data on land

cover and use, soil erosion, prime farmland soils, wetlands, habitat

diversity, conservation practices, and related resource attributes on

non-federal land in the U.S. 2) Soil erosion estimates were calculated

using the USGS watersheds, NRI soils data, and the Universal Soil

Loss Equation (Renard et al., 1997) and the Wind Erosion Equation

(Bondy et al., 1980; Skidmore and Woodruff, 1968). 3) Soil parameters were obtained from the USDA Natural Resources Conservation

Service (NRCS) soils database. The State Soil Geographic Database

(STATSGO) consists of state general soil maps made by generalizing

the detailed soil survey data. The level of mapping is designed to be

used for broad planning and management uses covering state,

regional, and multi-state areas. STATSGO data are designed for use

in a Geographic Information System (GIS). The mapping scale for

STATSGO map is 1:250,000 (with the exception of Alaska, which is

1:1,000,000). Each STATSGO map is linked to the Soil

Interpretations Record (SIR) attribute data base. The attribute data

base gives the proportionate extent of the component soils and

their properties for each map unit. The STATSGO map units consist

of 1 to 21 components each. The Soil Interpretations Record data
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-43

base includes over 25 physical and chemical soil properties, interpretations, and productivity. Examples of information that can be

queried from the data base are available water capacity, soil reaction,

salinity, flooding, water table, bedrock, and interpretations for engineering uses, cropland, woodland, rangeland, pastureland, wildlife,

and recreation development.

Indicator derivation (project, program, organization, report):

Data are from 1) USDA, NRCS STATSGO soils data and 2) 

USDA, NRCS NRI 1997 data (adjusted in 2000). Presented in The

State of the Nation’s Ecosystems, pages 100 and 235 (The Heinz 

Center, 2002).

Web site: NRI http://www.nrcs.usda.gov/technical/NRI/; 

STATSGO http://www.ftw.nrcs.usda.gov/stat_data.html

Grasslands and Shrublands 

Indicator name: At-risk native grasslands and shrublands species

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of grasslands

and shrublands?

Spatial coverage: National

Spatial coverage: Natural Heritage programs in all 50 states.

Temporal coverage: 2000. Data managed consistently since 1974.

Characterization of supporting data set(s): NatureServe is an

independent nonprofit organization whose research biologists

gather, review, integrate, and record available information about

species taxonomy, status, and use of different habitats or ecological

system types. They are assisted in this work by scientists in the

network of Natural Heritage programs as well as by contracted

experts for different invertebrate taxa. NatureServe staff and

collaborators assign a conservation status by using standard

Heritage ranking criteria. The Heritage ranking process considers five

major status ranks: critically imperiled (G1), imperiled (G2),

vulnerable (G3), apparently secure (G4), and demonstrably

widespread, abundant, and secure (G5). In addition, separate ranks

are assigned for species regarded as presumed extinct (GX) or

possibly extinct (GH).

Indicator derivation (project, program, organization, report):

NatureServe and its member programs in the network of Natural

Heritage programs develop and maintain information on species at

risk. Presented in The State of the Nation’s Ecosystems, pages 168 and

214 (The Heinz Center, 2002).

Web site: http://www.natureserve.org

Indicator name: Population trends in invasive and native non-invasive bird species

Indicator type (status or trend): Trend

Indicator category: 1

Associated question: What is the ecological condition of grasslands

and shrublands?

Spatial coverage: National

Temporal coverage: Data were analyzed in seven 5-year intervals

from 1966 to 2000. 

Characterization of supporting data set(s): The North American

Breeding Bird Survey (BBS) is a long- term, large-scale international

avian monitoring program intended to track the status and trends of

North American bird populations. Today there are approximately

3700 active BBS routes across the continental U.S. and Canada of

which 2900 are surveyed each year (Sauer, et al., 2001). 

Indicator derivation (project, program, organization, report):

U.S. Geological Survey’s Biological Resources Division, Breeding Bird

Survey. Presented in The State of the Nation’s Ecosystems, pages 170

and 262 (The Heinz Center, 2002).

Web site: BBS 

http://www.mbr-pwrc.usgs.gov/bbs/introbbs.html and

http://www.mp2- pwrc.usgs.gov/bbs/; 

Sauer, et al. http://www.mbr-pwrc.usgs.gov/bbs/trend/tfmb.html

Urban and Suburban Lands

Indicator name: Patches of forest, grassland, shrubland, and wetland

in urban/suburban areas

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of urban and

suburban areas?

Spatial coverage: Lower 48 states

Temporal coverage: 1992 satellite imagery

Characterization of supporting data set(s): NLCD provides a 

consistent, uniform, spatially explicit description of general land

cover/land use across the continental U.S. at a 30-meter resolution.

It does not contain habitat types. Eight of the 21 NLCD classifications were defined as “natural” for this analysis, including three classes of forest, three types considered grasslands/shrublands, and two

wetlands types (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

Multi-Resolution Land Characterization Consortium (MRLC) -

National Land Characterization Data (NLCD). Data analyses were

undertaken by the U.S. Geological Survey’s Earth Resources

Observations Systems (EROS) Data Center. Presented in The State 

of the Nation’s Ecosystems, pages 183 and 266 (The Heinz 

Center, 2002).
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-44 Indicator Metadata Appendix B

Web sites: MRLC http://www.epa.gov/mrlc/; 

EROS Data Center “raw” data (requiring “considerable computing

power” (The Heinz Center, 2002) http://edcwww.cr.usgs.gov/program/lccp/mrlcreg.html

Fresh Waters

Indicator name: Extent of ponds, lakes, and reservoirs

Indicator type (status or trend): Trend

Indicator category (1 or 2): 1

Associated question: What is the ecological condition of fresh waters?

Spatial coverage: Lower 48 states. Lake area does not include 

the Great Lakes, which cover about 60.2 million acres within the

United States.

Temporal coverage: 1950s-1990s

Characterization of supporting data set(s): The U.S. Fish and

Wildlife Service’s National Wetlands Inventory (NWI) counts all lakes,

reservoirs, and ponds regardless of land ownership. A permanent

study design is used, based initially on stratification of the 48 conterminous states by state boundaries and 35 physiographic subdivisions. Within these subdivisions are 4375 randomly selected sample

plots that are examined with the use of aerial imagery of varying

scale and type. Ponds include the category of open- water ponds

and non-vegetated palustrine wetlands (mud flats and shorelines of

ponds) generally less than six feet deep and less than 20 acres in

size. Lakes and reservoirs are generally larger than 20 acres and

deeper than six feet (The Heinz Center, 2002).

Indicator source (project, program, organization, report): Data

for lakes, reservoirs, and ponds come from 1) Dahl, T.E. Status and

Trends of Wetlands in the Conterminous United States 1986 to 1997,

Washington, DC: U.S. Department of the Interior, U.S. Fish and

Wildlife Service, 2000; 2) Dahl, T.E., and C.E. Johnson. Status and

Trends of Wetlands in the Conterminous United States, Mid-1970’s to

Mid-1980’s, Washington, DC: U.S. Department of the Interior, U.S.

Fish and Wildlife Service, 1991; 3) Frayer, W.E., T.J. Monahan, D.C.

Bowden, and F.A. Graybill. Status and Trends of Wetlands and

Deepwater Habitats in the Conterminous United States, 1950’s to

1970’s, Fort Collins, CO: Colorado State University, Department of

Forest and Wood Sciences, 1983; and 4) unpublished data from the

U.S. Fish and Wildlife Service (The Heinz Center, 2002). Presented in

The State of the Nation’s Ecosystems, pages 139 and 246 (The Heinz

Center, 2002).

Web site: Dahl, 2000 

http://wetlands.fws.gov/bha/SandT/ SandTReport.html

Indicator name: At-risk native fresh water species 

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the ecological condition of fresh

waters?

Spatial coverage: Natural Heritage programs in all 50 states.

Temporal coverage: 2000. Data managed consistently since 1974.

Characterization of supporting data set(s): NatureServe is an

independent nonprofit organization whose research biologists

gather, review, integrate, and record available information about

species taxonomy, status, and use of different habitats or ecological

system types. They are assisted in this work by scientists in the

network of Natural Heritage programs as well as by contracted

experts for different invertebrate taxa. NatureServe staff and

collaborators assign a conservation status by using standard

Heritage ranking criteria. The Heritage ranking process considers five

major status ranks: critically imperiled (G1), imperiled (G2),

vulnerable (G3), apparently secure (G4), and demonstrably

widespread, abundant, and secure (G5). In addition, separate ranks

are assigned for species regarded as presumed extinct (GX) or

possibly extinct (GH).

Indicator derivation (project, program, organization, report):

NatureServe and its member programs in the network of Natural

Heritage programs develop and maintain information on species at

risk. Presented in The State of the Nation’s Ecosystems, pages 144 and

214 (The Heinz Center, 2002).

Web site: http://www.natureserve.org/explorer

Indicator name: Non-native fresh water species 

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the condition of fresh waters?

Spatial coverage: Lower 48 states

Temporal coverage: 2000. An expansive spatial database underlies

the Nonindigenous Aquatic Species (NAS) program, which was 

created in 1978 and continues to be updated and revised.

Characterization of supporting data set(s): Roughly 90 percent

of the data in the U.S. Geological Survey’s NAS database are derived

from the published literature. Data are collected for the most part by

federal and state biologists, although the public does contribute by

reporting sightings (The Heinz Center, 2002). NAS is a repository

for accurate and spatially referenced biogeographic accounts of 

nonindigenous aquatic species. Provided are scientific reports,

online/realtime queries, spatial data sets, regional contact lists, and

general information. The data is made available for use by biologists,

interagency groups, and the general public. 

Indicator derivation (project, program, organization, report):

U.S. Geological Survey, Biological Resources Division (BRD), NAS

Database. Presented in The State of the Nation’s Ecosystems, pages

145 and 251 (The Heinz Center, 2002).
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-45

Web site: http://nas.er.usgs.gov/

Indicator name: Animal deaths and deformities

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the ecological condition of fresh

waters?

Spatial coverage: National. Database covers all 50 states, Puerto

Rico, and the U.S. Virgin Islands

Temporal coverage: 1985-1999

Characterization of supporting data set(s): The National Wildlife

Health Center (NWHC) maintains a database that contains wildlife

disease and mortality events information on avian, mammalian, and

amphibian mortality events. Information in the database is provided

by various sources, such as state and federal personnel, diagnostic

laboratories, wildlife refuges, and published reports (The Heinz

Center, 2002).

Indicator derivation (project, program, organization, report):

U.S. Geological Survey, Biological Resource Division (BRD), NWHC.

Presented in The State of the Nation’s Ecosystems, pages 146 and 252

(The Heinz Center, 2002).

Web site: http://www/mwhc.usgs.gov/pub_metadata/ qrt_mortality_report.html

Indicator name: At-risk fresh water plant communities

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the ecological condition of fresh

waters?

Spatial coverage: Natural Heritage programs in all 50 states, but

this coverage excludes Alaska

Temporal coverage: 2000. Data managed consistently since 1974.

Characterization of supporting data set(s): NatureServe is an

independent nonprofit organization whose research biologists 

gather, review, integrate, and record available information about

species taxonomy, status, and use of different habitats or ecological

system types. They are assisted in this work by scientists in the network of Natural Heritage programs as well as by contracted experts

for different invertebrate taxa. NatureServe staff and collaborators

assign a conservation status by using standard Heritage ranking 

criteria. The Heritage ranking process considers five major status

ranks: critically imperiled (G1), imperiled (G2), vulnerable (G3),

apparently secure (G4), and demonstrably widespread, abundant,

and secure (G5). In addition, separate ranks are assigned for species

regarded as presumed extinct (GX) or possibly extinct (GH).

Indicator derivation (project, program, organization, report):

NatureServe and its member programs in the network of Natural

Heritage programs develop and maintain information on species at

risk. Presented in The State of the Nation’s Ecosystems, 148 and 253

(The Heinz Center, 2002).

Web site: http://www.natureserve.org

Indicator name: Fish Index of Biotic Integrity (IBI) in streams

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the ecological condition of fresh

waters?

Spatial coverage: Statistically selected stream sites in the MidAtlantic Highlands (parts of Virginia, Maryland, Pennsylvania, and

New York and all of West Virginia) 

Temporal coverage: 1993-1994 sampling years

Characterization of supporting data set(s): About 450 stream

reaches were sampled in the Mid-Atlantic Highlands. To describe the

condition of all streams within the Highlands without sampling all of

them EMAP worked with EPA Region 3 and the states to develop a

regional statistical survey of streams. Examples of fish metrics 

measured were: the number of fish species present in the stream who

cannot tolerate pollution; the proportion of individuals present that

require clean gravel for spawning; and the number of bottom versus

water column species present. Each metric was scored against the

researchers expectations of what value was possible for each stream

based on reference conditions.

Indicator derivation (project, program, organization, report):

1)Mid-Atlantic Integrated Assessment (MAIA), Environmental

Monitoring and Assessment Program (EMAP), U.S. Environmental

Protection Agency, Mid-Atlantic Highlands Streams Assessment,

EPA/903/R-00/015, August 2000. 2) McCormick, F.H., R.M.

Hughes, P.R. Kaufmann, D.V. Peck, J.L. Stoddard, and A.T. Herlihy.

Development of an index of biotic integrity for the Mid-Atlantic

Highlands Region. Transactions of the American Fisheries Society 130:

857-877 (2001).

Web site: MAIA Report http://www.epa.gov/maia/html/maha.html

Indicator name: Macroinvertebrate Biotic Integrity Index (MBII) for

streams

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the condition of fresh waters?
EPA’s Draft Report on the Environment 2003 Q Technical Document

B-46 Indicator Metadata Appendix B

Spatial coverage: Statistically selected stream sites in the MidAtlantic Highlands (parts of Virginia, Maryland, Pennsylvania, and

New York and all of West Virginia) 

Temporal coverage: 1993-1994 sampling years

Characterization of supporting data set(s): About 450 stream

reaches were sampled in the Mid-Atlantic Highlands. To describe the

condition of all streams within the Highlands without sampling all of

them EMAP worked with EPA Region 3 and the states to develop a

regional statistical survey of streams. One aquatic insect index, EPT,

has been used extensively to evaluate stream condition throughout

the United States and was used in the Highlands. It is calculated

from the number of species that are found in three orders of aquatic

insects–mayflies (Ephemeoptera), stoneflies (Plecoptera), and caddisflies (Trichoptera) and gets its name from the first initials of these

three orders (EPT). Many of the species in these three orders are

sensitive to pollution and other stream disturbances, and the total

number of species is a good gauge of how disturbed any given

stream may be. EPT scores from least-disturbed Highland streams

were used to set expectations. Expectations were set separately for

streams with fast-moving sections or “riffles” (the vast majority of

Highland streams) and slow-moving streams where “pools” dominate,

because fewer EPT species naturally occur in pools.

Indicator derivation (project, program, organization, report):

1) Klemm, D.J., K.A. Blocksom, F.A. Fulk, A.T. Herlihy, R.M. Hughes,

P.R. Kaufmann, D.V. Peck, J.L. Stoddard, W.T. Thoeny, M.B. Griffith,

and W.S. Davis. Development and Evaluation of a Macroinvertebrate

Biotic Integrity Index (MBII) for Regionally Assessing Mid-Atlantic

Highlands Streams. Environmental Management 31(5): 656-669

(2003). 2) Mid-Atlantic Integrated Assessment (MAIA),

Environmental Monitoring and Assessment Program (EMAP), U.S.

Environmental Protection Agency, Mid-Atlantic Highlands Streams

Assessment, EPA/903/R-00/015, August 2000.

Web site: MAIA Report http://www.epa.gov/maia/html/maha.html

Coasts and Oceans

Indicator name: Extent of estuaries and coastline

Indicator type (status or trend): Status

Indicator category (1 or 2): 1

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National, all 50 states and territories

Temporal coverage: 1996-1998

Characterization of supporting data set(s): Data were submitted

by the states and territories to EPA’s Office of Water which compiled

a national report. Data were collected using different methodologies,

definitions, and assumptions, so the data is unlikely to be consistent.

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency, Office of Water, 2000 National

Water Quality Inventory, EPA 841-R-02-001, August 2002, Table C-1

Total Estuarine and Ocean Shoreline Waters in the Nation.

Web site: http://www.epa.gov/305b/2000report/appendixc.pdf

Indicator name: Coastal living habitats

Indicator type (status or trend): Trend

Indicator category: 2 

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National

Temporal coverage: 1950s to 1990s

Characterization of supporting data set(s): While data gaps are

reported for the coral reef, seagrasses, and shellfish beds components of the indicator (The Heinz Center, 2002), the wetlands 

component is supported by U.S. Fish and Wildlife Service’s (USFWS)

recent report, The Status and Trend of Wetlands in the Conterminous

United States 1986-1997. The report utilizes National Wetlands

Inventory (NWI) and other wetland data. NWI counts all wetlands,

regardless of land ownership, but recognizes only wetlands that are

at least three acres. To ensure adequate coverage of coastal 

wetlands, supplemental sampling along the Atlantic and Gulf coast

fringes was added (The Heinz Center, 2002).

Indicator source (project, program, organization, report): Dahl,

T.E. Status and Trends of Wetlands in the Conterminous United States

1986 to 1997, Washington, DC: U.S. Department of the Interior, U.S.

Fish and Wildlife Service, 2000. Presented in The State of the Nation’s

Ecosystems, pages 69 and 218 (The Heinz Center, 2002).

Web site: http://wetlands.fws.gov/bha/SandT/SandTReport.html

Indicator name: Shoreline types

Indicator type (status or trend): Status

Indicator category: 2 

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National in scope; Pacific Northwest, Southern

California, and South Atlantic regions only

Temporal coverage: 1984-2001

Characterization of supporting data set(s): Data were extracted

from Environmental Sensitivity Index (ESI) atlases, a product of the

National Oceanic and Atmospheric Administration’s (NOAA), Office

of Response and Restoration (ORR). The ESI method provides a

standardized mapping approach for coastal geomorphology as well

as biological and human use elements. Data from multiple atlases
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix B Indicator Metadata B-47

were aggregated into the regions used. Some of the data atlases 

utilized were more than 15 years old (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

NOAA, ORR, Hazardous Materials Response Division, ESI atlases.

Presented in The State of the Nation’s Ecosystems, pages 70 and 219

(The Heinz Center, 2002).

Web site: Some NOAA ESI data are available at

http://response.restoration.noaa.gov/esi/esiintro.html

Indicator name: Benthic Community Index

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National in scope, 24 coastal states

Temporal coverage: Stations on the west coast were sampled in

1999. The entire U.S. coast, including the Gulf of Maine, was sampled in 2000. 

Characterization of supporting data set(s): In 2000, EPA, NOAA,

and USGS, in cooperation with all 24 U.S. coastal states, initiated

the National Coastal Assessment. Using a compatible, probabilistic

design and a common set of survey indicators, each state conducted

the survey and independently assessed the condition of their coastal

resources. While the complete assessment of national coastal waters

is scheduled for publication in 2003, a preliminary assessment of

selected estuaries was published by EPA in 2001. The EPA

Environmental Monitoring and Assessment Program (EMAP) 

National Coastal Database contains estuarine and coastal data that

EMAP and Regional-EMAP have collected since 1990 from hundreds

of stations between Cape Cod and the Mexican border. These

include water column data, sediment chemistry and toxicity data,

demersal fish and invertebrate community and contaminant data 

and benthic invertebrate community data. 

Indicator derivation (project, program, organization, report):

1) EMAP National Coastal Database; 2) U.S. Environmental

Protection Agency. National Coastal Condition Report, EPA 620-R-01-

005. Washington DC: U.S. Environmental Protection Agency, Office

of Research and Development and Office of Water, September 2001.

Web site: NCCR

http://epa.gov/owow/oceans/nccr/downloads.html; 

National Coastal Database

http://www.epa.gov/emap/nca/html/data/index.html

Indicator name: Fish diversity

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: Mid-Atlantic estuaries 

Temporal coverage: 1997-1998

Characterization of supporting data set(s): The EPA Mid-Atlantic

Integrated Assessment (MAIA) Estuaries Summary Database contains

water quality, sediment, benthic community, and fish data collected

by several partners in MAIA Region estuaries in 1997 and 1998. The

MAIA program conducted regular fish surveys during the summer of

1998 to characterize the structure and health of the fish communities. The stations sampled were selected according to a probabilistic

design. These stations were not identical with the stations sampled

for water and sediment quality analyses conducted primarily in 1997;

therefore, it is not possible to directly compare these different

analyses station by station. However, it is statistically valid to compare results among classes of estuaries, (e.g., large versus small estuaries, Delaware Estuary versus Chesapeake Estuary).

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. Mid- Atlantic Integrated Assessment,

MAIA - Estuaries 1997-98, Summary Report, EPA 620-R-02-003.

Narragansett, RI: U.S. Environmental Protection Agency, Office of

Research and Development, Atlantic Ecology Division, May 2003. 

Web site: MAIA data http://www.epa.gov/emap/maia/html/data/

estuary/9798/xport.html

Indicator name: Submerged aquatic vegetation

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: Mid-Atlantic estuaries, Chesapeake Bay

Temporal coverage: 1985-1998

Characterization of supporting data set(s): The Chesapeake 

Bay Program’s second submerged aquatic vegetation (SAV) Technical

Synthesis revises and updates the first synthesis published in 1992,

by providing new light requirements for SAV through the water 

column and at the leaf surface, providing diagnostic tools for their

application and interpretation, and identifying preliminary sets of

physical, chemical, and other biological habitat requirements. An

algorithm was applied to analyze SAV habitat suitability for some 50

sites in Chesapeake Bay and its tidal tributaries using data collected

over 14 years (1985-1998) of environmental monitoring (EPA, CBP,

2000). 2) Mid-Atlantic Integrated Assessment (MAIA) field crews

noted the presence or absence of SAV at their sampling stations as

an ancillary measurement. No attempt was made to estimate the

extent of SAV the MAIA region. The MAIA database contains water

quality, sediment, benthic community, and fish data collected by 
B-48 Indicator Metadata Appendix B

several partners in MAIA Region estuaries in 1997 and 1998. The

MAIA program conducted regular fish surveys during the summer of

1998 to characterize the structure and health of the fish communities. The stations sampled were selected according to a probabilistic

design. These stations were not identical with the stations sampled

for water and sediment quality analyses conducted primarily in 

1997; therefore, it is not possible to directly compare these different

analyses station by station. However, it is statistically valid to 

compare results among classes of estuaries, (e.g., large versus small

estuaries, Delaware Estuary versus Chesapeake Estuary).

Indicator source (project, program, organization, report):

1) Batiuk, R.A., P. Bergstrom, M. Kemp, E. Koch, L. Murray, J.C.

Stevenson, R. Bartleson, V. Carter, N.B. Rybicki, J.M. Landwehr, C.

Gallegos, L. Karrh, M. Naylor, D. Wilcox, K.A. Moore, S. Ailstock, and

M. Teichberg. Chesapeake Bay Submerged Aquatic Vegetation Water

Quality and Habitat-Based Requirements and Restoration Targets: A

Second Technical Synthesis, CBP-TRS 245-00, EPA 903-R-00-014.

Annapolis, MD: U.S. Environmental Protection Agency, Chesapeake

Bay Program, 2000; 2) U.S. Environmental Protection Agency. MidAtlantic Integrated Assessment, MAIA - Estuaries 1997-98, Summary

Report, EPA 620-R-02-003. Narragansett, RI: U.S. Environmental

Protection Agency, Office of Research and Development, Atlantic

Ecology Division, May 2003. 

Web site: CBP report

http://www.chesapeakebay.net/pubs/ sav/index.html

Indicator name: Fish abnormalities

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National assessment, data presented for Gulf of

Mexico to Cape Cod, Great Lakes excluded

Temporal coverage: Data collected in 2000, available in 2002 for

Pacific Coast

Characterization of supporting data set(s): U.S. Environmental

Protection Agency Environmental Monitoring and Assessment

Program (EMAP) data on fish pathologies by estuarine province. 

Indicator source (project, program, organization, report): U.S.

Environmental Protection Agency. National Coastal Condition Report,

EPA 620-R-01-005. Washington DC: U.S. Environmental Protection

Agency, Office of Research and Development and Office of Water,

September 2001.

Web site: NCCR http://epa.gov/owow/oceans/nccr/downloads.html

Indicator name: Unusual marine mortalities

Indicator type (status or trend): Status

Indicator category: 2

Associated question: What is the ecological condition of coasts

and oceans?

Spatial coverage: National in scope for marine mammals

Temporal coverage: 1992-2001

Characterization of supporting data set(s): Data is available for

whales, dolphins, porpoises, seals, sea lions, sea otters, and manatees. Data is not available for turtle, seabird, fish, and shellfish 

mortality. The 2001 data for two unusual mortality events and the

total number of gray whales lost in the 1999-2001 unusual mortality

event were obtained directly from National Marine Fisheries Service

(NMFS). All other unusual mortality event data were obtained from

Dierauf and Gulland, (2001) (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

1) U.S. Department of Commerce, NOAA, NMFS, Office of Protected

Resources, Marine Mammal Health and Stranding Response Program;

2) Dierauf, L.A., and F.M.D. Gulland (eds.) CRC Handbook of Marine

Mammal Medicine: Health, Disease, and Rehabilitation, 2nd Edition,

Boca Raton, FL: CRC Press, Inc., 2001. Presented in The State of the

Nation’s Ecosystems, pages 77 and 223 (The Heinz Center, 2002).

Web site: NMFS data

http://www.nmfs.noaa.gov/prot_res/PR2/Health_and_Stranding_

Response_Program/WGUMMME.html

The Entire Nation

Indicator name: Ecosystem extent

Indicator type (status or trend): Status and Trend

Indicator category (1 or 2): 2

Associated question: What is the ecological condition of the 

entire nation?

Spatial coverage: National in all cases

Temporal coverage: 1950s-1990s.

Characterization of supporting data set(s): 1) For cropland, the

data source is the USDA Economic Research Service (ERS) relying 

on data from the National Agricultural Statistics Service and a variety

of other sources to provide an estimate of extent. 2) For forests, the

data source is the USDA Forest Service Forest Inventory and Analysis

(FIA) program, a survey-based program that has operated since the

late 1940s, collecting information on a variety of forest characteristics. 3) For fresh water wetlands, the data source is the U.S. Fish and

Wildlife Service’s National Wetlands Inventory as reported in the

most recent wetlands status and trends report (Dahl, 2000). 4) For

grasslands and shrublands, the data source is the National Land

Cover Dataset (NLCD). In the 1990s, a federal interagency consortium (the Multi- Resolution Land Characterization (MRLC)

Consortium) was created to coordinate access to and use of land

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Appendix B Indicator Metadata B-49

cover data from the Landsat 5 Thematic Mapper. Using Landsat data

and a variety of ancillary data, the consortium processed data from a

series of 1992 Landsat images, to create the NLCD on a square grid

covering the lower 48 states. The MRLC NLCD with 21 land cover

classes, was used to estimate the area coverage for the U.S. 5) For

urban/suburban, the data source is the NLCD.

Indicator derivation (project, program, organization, report):

1) ERS; 2) FIA; 3) Dahl, T.E. Status and Trends of Wetlands in the

Conterminous United States 1986 to 1997, Washington, DC: U.S.

Department of the Interior, U.S. Fish and Wildlife Service, 2000; 

4) NLCD; 5) NLCD. Presented in The State of the Nation’s Ecosystems,

pages 41-43 and 207 (The Heinz Center, 2002).

Web site: ERS

http://www.ers.usda.gov/Emphases/Harmony/issues/arei2000/; 

FIA http://fia.fs.fed.us; 

Dahl, 2000 http://wetlands.fws.gov/bha/SandT/SandTReport.html;

NLCD http://www.usgs.gov/mrlcreg.html

Indicator name: At-risk native species

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of the entire

nation?

Spatial coverage: Natural Heritage programs in all 50 states.

Temporal coverage: 2000. Data managed consistently since 1974.

Characterization of supporting data set(s): NatureServe is an

independent nonprofit organization whose research biologists 

gather, review, integrate, and record available information about

species taxonomy, status, and use of different habitats or ecological

system types. They are assisted in this work by scientists in the 

network of Natural Heritage programs as well as by contracted

experts for different invertebrate taxa. NatureServe staff and collaborators assign a conservation status by using standard Heritage ranking criteria. The Heritage ranking process considers five major status

ranks: critically imperiled (G1), imperiled (G2), vulnerable (G3),

apparently secure (G4), and demonstrably widespread, abundant,

and secure (G5). In addition, separate ranks are assigned for species

regarded as presumed extinct (GX) or possibly extinct (GH).

Indicator derivation (project, program, organization, report):

NatureServe and its member programs in the network of Natural

Heritage programs develop and maintain information on species at

risk. Presented in The State of the Nation’s Ecosystems, pages 52-53

and 214 (The Heinz Center, 2002).

Web site: http://www.natureserve.org

Indicator name: Bird Community Index

Indicator type (status or trend): Status

Indicator Category: 2

Associated question: What is the ecological condition of the 

entire nation?

Spatial coverage: Mid-Atlantic Highlands (parts of Virginia,

Maryland, Pennsylvania, and New York and all of West Virginia) 

Temporal coverage: 1995-1996 data

Characterization of supporting data set(s): Birds and vegetation

were surveyed across the entire Mid-Atlantic highlands within sites

sufficiently large (200 acres) to represent most of the habitat

elements that are required by breeding birds. Use of EPA’s

Environmental Monitoring and Assessment Program (EMAP) survey

design guaranteed that data from the 126 sample sites were

representative of the entire highlands area. Sixteen specific groups of

bird species, such as omnivores, bark probers, residents, migrants,

shrub nesters, etc., were ultimately selected as representative of the

mostly forested Mid-Atlantic Highlands area. Of the 16 groups, nine

were “specialists” and seven were “generalists”; for example,

insectivores are specialists and omnivores are generalists. Placement

of specific bird species within each group was based on a review of

scientific publications. Species may be assigned to several groups as

well as to both specialist and generalist groups simultaneously. In

general, a high proportion of birds with specialized requirements

indicates healthy natural habitat that provides ecological benefits at

local and larger scales (EPA, 2000).

Indicator derivation (project, program, organization, report):

1) O’Connell, T.J., L.E. Jackson, and R.P. Brooks. Bird guilds as indicators of ecological condition in the central Appalachians. Ecological

Applications 10: 1706-1721 (2000). 2) U.S. Environmental

Protection Agency. MAIA Project Summary: Birds Indicate Ecological

Condition of the Mid-Atlantic Highlands. EPA 620-R-000-003.

Washington, DC: EPA, Office of Research and Development, June

2000.

Web site: MAIA summary http://www.epa.gov/maia/html/bird.htm;

Full research report http://www.wetlands.cas.psu.edu

Indicator name: Terrestrial Plant Growth Index

Indicator type (status or trend): Status and Trend

Indicator Category: 1

Associated question: What is the ecological condition of the entire

nation?

Spatial coverage: Lower 48 states

Temporal coverage: 1989-2000, except for 1994 when the 

satellite failed. The Normalized Difference Vegetation Index (NDVI) is

calculated at two-week intervals and summed throughout the growing season; only values that exceed non-growing-season, background

NDVI are included. Growing season dates, end dates, and back-
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B-50 Indicator Metadata Appendix B

ground NDVI were calculated for each land cover type and region

(The Heinz Center, 2002).

Characterization of supporting data set(s): The plant growth

index is based on data collected by the Advanced Very High

Radiation Radiometer (AVHRR) aboard NOAA’s polar orbiting

satellites. Because the relationship between NDVI and absorbed

photosynthetically active radiation varies by cover type, the growing

season accumulated NDVI was calculated separately for the forest,

farmland, and grassland/shrubland areas in each county of the

conterminous 48 states. The 11-year average growing- season

accumulated NDVI was also calculated for each of the three land

cover types in each county. The values in each county segment for

each year were then normalized by using the corresponding 11-year

average for that county segment to produce a plant growth index

where a value of 1.0 equals the long-term average. Areas with plant

growth indices greater than 1.0 have higher-than-average

accumulated NDVI; within the same cover type and in an area as

small as a county, this implies higher-than-average plant growth for

that year. The regional and system specific plant growth indices are

the area-weighted averages of the segments contained within the

region and system (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

Data on accumulated NDVI and analysis of those data are from the

USGS’s Earth Resources Observations Systems (EROS) Data Center,

Sioux Falls, South Dakota. Presented in The State of the Nation’s

Ecosystems, pages 56-57 and 216 (The Heinz Center, 2002).

Web site: http://edcwww.cr.usgs.gov/ 

Indicator name: Movement of nitrogen

Indicator type (status or trend): Status

Indicator Category: 1

Associated question: What is the ecological condition of the 

entire nation?

Spatial coverage: Lower 48 states

Temporal coverage: 1996-1999

Characterization of supporting data set(s): Riverine loads of total

nitrogen were estimated using streamflow and water-quality data

collected by the U.S. Geological Survey as part of its National

Stream Water Accounting Network (NASQAN), its 1996-1999

National Water Quality Assessment (NAWQA), and its Federal State

Cooperative Program. At the sites for which data are included in this

indicator, samples were collected at least quarterly over the four-year

period and at most sites, approximately 15 samples were collected

each year. A regression model relating nitrogen concentration to

discharge, day- of-year (to capture seasonal effects), and time (to

capture any trend over the period) was developed. Another model

was developed for nitrate plus nitrite concentrations (note that

nitrite is usually much less abundant than nitrate, so it is normal to

discuss the sum of nitrate plus nitrite simply as nitrate) and a third

model was developed for whole-water organic nitrogen plus ammonia

for each station. These models were then used to make daily

estimates of concentration, which were multiplied by the daily

average discharge to yield the daily load. The daily load of total

nitrogen was the sum of predictions of the latter two models 

(The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

USGS, NASQAN and NAWQA programs, and the USGS Federal-State

Cooperative Program. Presented in The State of the Nation’s

Ecosystems, pages 46-47 and 210 (The Heinz Center, 2002).

Web site: NASQAN http://water.usgs.gov/nasqan; 

NAWQA http://water.usgs.gov/nawqa

Indicator name: Chemical contamination

Indicator type (status or trend): Trend

Indicator Category: 2

Associated question: What is the ecological condition of the entire

nation?

Spatial coverage: Lower 48 states

Temporal coverage: 1990-1997 (EMAP) and 1992-1998 (USGS)

Characterization of supporting data set(s): 1) The data for freshwater streams and ground water were collected and analyzed by the

U.S. Geological Survey’s (USGS), National Water Quality Assessment

(NAWQA) in 36 major river basins and aquifers across the U.S. 

2) The data for sediments and fish contamination in coastal waters

were collected and analyzed by the U.S. Environmental Protection

Agency’s, Environmental Monitoring and Assessment Program

(EMAP) in a manner that allows conclusions to be drawn concerning

the majority (approximately 76 percent) of the areas of estuaries in

the U.S. 3) Data on sediment contamination in the Great Lakes are

collected by a number of agencies and were provided by EPA’s Great

Lakes National Program Office (The Heinz Center, 2002).

Indicator derivation (project, program, organization, report):

1) USGS, NAWQA; 2) EPA, EMAP; and 3) Great Lakes National

Program Office. Presented in The State of the Nation’s Ecosystems,

pages 48-51 and 210 (The Heinz Center, 2002).

Web site: NAWQA http://water.usgs.gov/nawqa; 

EMAP http://www.epa.gov/emap/
Appendix C: 

Acronyms and

Abbreviations
C-2 Acronyms and Abbreviations Appendix C

A

1NAP: 1-napthol

AFO: animal feeding operation

AHA: American Heart Association

AHEF: Atmospheric and Health Effects Framework

AIRS: Aerometric Information Retrieval System

AM: atrazine mercapturate

ANC: acid-neutralizing capacity

APCs: areas of probable concern

AQI: Air Quality Index

AQS: Air Quality System

AREAL: Atmospheric Research and Exposure Assessment Laboratory

ARS: Agricultural Research Center

ATSDR: Agency for Toxic Substances and Disease Registry

AVHRR: advanced very high resolution radiometer

AVS: acid volatile sulfide

B

BASE: Building Assessment Survey and Evaluation

BBS: Breeding Bird Survey

BCI: Bird Community Index

BEACH: Beaches Environmental Assessment and Coastal Health

Program

BEIR VI: Biological Effects of Ionizing Radiation

BLM: Bureau of Land Management

BRAC: base realignment and closure facilities

BRD: Biological Resources Division

C

C&I: criteria and indicators

CAA: Clean Air Act

CAFOs: confined animal feeding operations

CAPI: computer-assisted personal interviewing

CASTNet: Clean Air Status and Trends Network

CBP: Chespeake Bay Program

CCA: chromate copper arsenate

C-CAP: Coastal Change Analysis Program

CDC: Centers for Disease Control and Prevention

CDDS: California Department of Developmental Services

CEMS: continuous emissions monitors

CENR: Council on the Environment and Natural Resources

CERCLA: Comprehensive Environmental Response, Compensation,

and Liability Act

CERCLIS: Comprehensive Environmental Response, Compensation,

and Liability Information System

CESQGs: conditionally exempt small quantity generators

CFCs: chloroflourocarbons

CHD: coronary heart disease

cm: centimeter

CMSAs: consolidated metropolitan statistical areas

CO: carbon monoxide

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Appendix C Acronyms and Abbreviations C-3

COHb: carboxyhemoglobin

COPD: chronic obstructive pulmonary disease

COS: carbonyl sulfide 

CPI: Consumer Price Index 

CPSC: Consumer Product Safety Commission

CRA: comparative risk assessment 

CRP: Conservation Reserve Program 

CSO: combined sewer overflow

CSTE: Council of State and Territorial Epidemiologists

CVD: cardiovascular disease

CWA: Clean Water Act

CWS: community water system

D

DBPs: disinfection byproducts

DDE: dichlorodiphenyldichloroethylene

DDT: dichlorodiphenltrichloroethane

DO: dissolved oxygen

DOC: dissolved organic carbon

DOE: U.S. Department of Energy

DOI: U.S. Department of the Interior

DSS: decision support systems

DU: Dobson Units 

E

EBD: environmental burden of disease

ECAO: Environmental Criteria and Assessment Office

ECI: Employee Cost Index

EDC: endocrine-disrupting compounds

EEA: essential ecological attribute

EECL: equivalent effective chlorine

EEZ: U.S. Exclusive Economic Zone

EMAP: Environmental Monitoring and Assessment Program

ENSO: El Niño-Southern Oscillation 

EPA: U.S. Environmental Protection Agency

STAR: Science to Achieve Results

EPCRA: Emergency Planning and Community Right-to-Know Act

EPHI: environmental public health indicators

EPO: Epidemiology Program Office

EPT: Ephemeoptera, Plecoptera, and Trichoptera Index 

ERL: effects range low

ERM: effects range medium

EROS: Earth’s Resources Observation System

ESG: Equilibrium Partitioning Sediment Guidelines

ESI: Environmental Sensitivity Index

ESRD: end stage renal disease

ETS: environmental tobacco smoke
C-4 Acronyms and Abbreviations Appendix C

F

FDA: Food and Drug Administration

FHM: Forest Health Monitoring Program

FIA: Forest Inventory and Analysis 

FQPA: Food Quality Protection Act

FS: Forest Service

FY: fiscal year

G

GAO: General Accounting Office

GBD: global burden of disease

GDP: gross domestic product

GI: gastrointestinal illness

GIS: geographic information systems

GLEAMS: groundwater loading effects of agricultural management

GPRA: Government Performance Results Act

H 

HABs: harmful algal blooms

HCB: hexachlorobenzene

HCFCs: hydrochlorofluorocarbons 

HFCs: hydrofluorocarbons

HHS: Department of Health and Human Services

HHW: household hazardous waste

HUC: hydrologic unit code

HUMUS: hydrologic unit modeling of the United States

I-J

IAQ: indoor air quality

IBI: index of biotic integrity 

ICCC: international classification of childhood cancer

ICTDRN: International Center for Tropical Disease Research

Network

IDEM: Indiana Department of Environmental Management

IMP: integrated pest management

IMPROVE: Interagency Monitoring of Protected Visual Environments

IPCS: International Programme on Chemical Safety

IQ: intelligence quotient

IRIS: Integrated Risk Information System

IWI: Index of Watershed Indicators

K-L

lbs: pounds

LDC: least distributed condition

LQGs: large quantity generators

LTER: long-term ecological research

LUST: leaking underground storage tanks

km: kilometers

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Appendix C Acronyms and Abbreviations C-5

M

MA: metropolitan area 

MAD: malathion dicarboxylic acid

MAIA: Mid-Atlantic Integrated Assessment

MBII: Macroinvertebrate Biotic Integrity Index

MCL: maximum contaminant levels

MDC: minimally distributed condition

MDN: Mercury Deposition Network

μ/m3: micrograms per cubic meter

μ/dl: micrograms per deciliter

μ/L: micrograms per liter

MRLC: Multi-Resolution Land Characteristics

MSAs: metropolitan statistical areas

N

N2: nitrogen

NAAQS: National Ambient Air Quality Standards

NADP: National Atmospheric Deposition Program

NAE: National Academy of Engineering

NAMS: national air monitoring stations

NAO: North Atlantic Oscillation

NAPAP: National Acid Precipitation Assessment Program 

NAS: Nonindigenous Aquatic Species

NASA: National Aeronautics and Space Administration

NASQAN: National Stream Quality Accounting Network

NASS: National Agricultural Statistics Service

NAWQA: National Water Quality Assessment Program

NCEA: National Center for Environmental Assessment

NCES: National Center for Education Strategies

NCEH: National Center for Environmental Health

NCFAP: National Center for Food and Agricultural Policy

NCHS: National Center for Health Statistics

NCI: National Cancer Institute

NCS: National Children’s Study

NDVI: Normalized Difference Vegetation Index

NEI: National Emissions Inventory

NEP: National Estuary Program

NEPA: National Environmental Policy Act

NERRS: National Estuarine Research Reserve System

ng/mL: nanograms per milliliter

NHANES: National Health and Nutrition Examination Survey

NHATS: National Human Adipose Tissue Survey

NH3: ammonia

NHD: National Hydrography Dataset

NHEXAS: National Human Exposure Assessment Survey

NHIS: National Health Interview Survey

NHLBI: National Heart, Lung, and Blood Institute

NIH: National Institutes of Health

NINDS: National Institute of Neurological Disorders and Stroke

NLCD: National Land Cover Data

NLFWA: National Listing of Fish and Wildlife Advisories
C-6 Acronyms and Abbreviations Appendix C

NLV: Norwalk-like virus

nm: nanometers

NMI: Nematode Maturity Index

MMWR: Morbidity and Mortality Weekly Report

NMVOCs: non-methane volatile organic compounds

NO2: nitrogen dioxide

NOx: nitrogen oxides

NOAA: National Oceanic and Atmospheric Administration

NOPES: Nonoccupational Pesticide Exposure Study

NPL: National Priorities List

NPP: Net Primary Production

NRC: National Research Council

NRCS: Natural Resources Conservation Service

NRI: National Resources Inventory

NSF: National Science Foundation

NSI: National Sediment Inventory

NSSP: National Sanitary Survey Program

NS&T: National Status and Trends Program

NTN: National Trends Network

NVSS: National Vital Statistics System

NWHC: National Wildlife Health Center

NWI: National Wetlands Inventory

O

O3: ozone

OAQPS: Office of Air Quality Planning and Standards

OAR: Office of Air and Radiation

OCFO: Office of the Chief Financial Officer

OCHP: Office of Children’s Health Protection

OCIR: Office of Congressional and Intergovernmental Relations

OECA: Office of Enforcement and Compliance Assurance

OEI: Office of Environmental Information

ODP: ozone-depleting potential

ODS: ozone-depleting substance

OE: Office of Enforcement

OECD: Organization for Economic Cooperation and Development

OPEI: Office of Policy, Economics, and Innovation

OPs: organophosphate pesticides

OPP: Office of Pesticide Programs

OPPE: Office of Policy, Planning, and Evaluation 

OPPT: Office of Pollution Prevention and Toxics

OPPTS: Office of Prevention, Pesticides, and Toxic Substances

ORD: Office of Research and Development

OSWER: Office of Solid Waste and Emergency Response

OW: Office of Water

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Appendix C Acronyms and Abbreviations C-7

P

P: phosphorus

PAH: polycyclic aromatic hydrocarbons

Pb: lead

PBTs: persistent bioaccumulative toxics

PCBs: polychlorinated biphenyls

PCC: poison control centers

PCDD: polychlorinated dibenzo-dioxin 

PCDF: polychlorinated dibenzo-furan

pCi/L: picocuries per liter

PDO: Pacific Decadal Oscillation

PDP: Pesticides Data Program

PECDF: pentachlorodibenzofuran

PERC: chloroform tetrachloroethylene

PFCs: perflourinated carbons

PIBI: Periphyton Index of Biotic Integrity

PM: particulate matter

PM10, PM2.5: particulate matter 10, 2.5 micrometers (coarse, fine)

PMSAs: primary metropolitan statistical areas 

POPs: persistent organic pollutants

POTW: publicly owned treatment works

PPI: Producer Price Index

PSR: pressure-state-response framework

PSR/E: pressure-state-response-effects framework

PWS: public water system

Q-R

QA/QC: quality assurance/quality control

RB meter: Robertson-Berger meter

RCRA: Resource Conservation and Recovery Act

RCRAInfo: Resource Conservation and Recovery Act Information

System

ReVA: Regional Vulnerability Assessment Program

RMSF: rocky mountain spotted fever

ROE: EPA’s Report on the Environment

RPA: Resource Planning Act

RUSLE: revised universal soil loss equation

S

SAB: Science Advisory Board

SARA: Superfund Amendment and Reauthorization Act

SAV: submerged aquatic vegetation

SDWA: Safe Drinking Water Act

SDWIS: Safe Drinking Water Information System

SDWIS/FED: Safe Drinking Water Information System/Federal

version

SeaWiFS: sea viewing wide field-of-view sonar

SEER: Surveillance, Epidemiology, and End Results Program

SEM: simultaneously extracted metals

SF6: sulfur hexafluoride

SIC: standard industrial classification

SIDS: sudden infant death syndrome
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C-8 Acronyms and Abbreviations Appendix C

SLAMS: state/local air monitoring stations

SMSA: Standard Metropolitan Statistical Area

SO2: sulfur dioxide

SOLEC: State of the Great Lakes Ecosystem Conference

SQI: Soil Quality Index 

SPARROW: SPAtially-Referenced Regression On Watershed

Attributes

SQGs: small quantity generators 

SSO: sanitary sewer overflow

SST: sea surface temperature

STATSGO: State Soil Geographic Database

STORET: STORage and RETrieval Database

SWAT: Soil and Water Assessment Tool

T

TBP: theoretical bioaccumulation potential

TCE: trichloroethylene

TDCF: tetrachlorodibenzofuran

TESS: Toxic Exposure Surveillance System

THMs: trihalomethanes

TIME: temporally integrated monitoring of ecosystems

TMDL: total maximum daily load

TN: total nitrogen

TOC: total organic carbon

TOMS: total ozone mapping spectrometer

TP: total phosphorus

TRI: Toxics Release Inventory

TD: Technical Document for EPA’s Report on the Environment

TSDs: treatment, storage, and disposal facilities

TYPY: 3,5,6-trichloro-2-pyridinol

U-Z

UAs: urbanized areas

UCs: urban clusters

UN: United Nations

UNEP: United Nations Environment Programme

USDA: U.S. Department of Agriculture

USFWS: U.S. Fish and Wildlife Service

USGS: U.S. Geological Survey

UST: underground storage tanks

UV: ultraviolet

UV-A: ultraviolet A

UV-B: ultraviolet B

VMT: vehicle miles traveled

VOCs: volatile organic compounds

WBDO: Waterborne disease outbreak

WHO: World Health Organization

WMO: World Meteorological Organization

WMPC: waste minimization priority chemicals
Appendix D: 

Glossary 

of Terms
D-2 Glossary of Terms Appendix D

A

accretion: The gradual build-up of sediment along the bank or

shore of a river or stream.

acid deposition: A complex chemical and atmospheric phenomenon

that occurs when emissions of sulfur and nitrogen compounds are

transformed by chemical processes in the atmosphere and then

deposited on earth in either wet or dry form. The wet forms, often

called “acid rain,” can fall to earth as rain, snow, or fog. The dry

forms are acidic gases or particulate matter.

adipose tissue: Fatty tissue.

advisory: A nonregulatory document that communicates risk

information to those who may have to make risk management

decisions. (EPA, December 1997)

aerosol: 1. Small droplets or particles suspended in the

atmosphere, typically containing sulfur. They are emitted naturally

(e.g., in volcanic eruptions) and as a result of human activities 

(e.g. burning fossil fuels). 2. The pressurized gas used to propel

substances out of a container. (EPA, December 1997)

agricultural waste: Byproducts generated by the rearing of animals

and the production and harvest of crops or trees. Animal waste, a

large component of agricultural waste, includes waste (e.g., feed

waste, bedding and litter, and feedlot and paddock runoff) from

livestock, dairy, and other animal-related agricultural and farming

practices. 

air pollutant: Any substance in air that could, in high enough

concentration, harm man, other animals, vegetation, or material.

Pollutants may include almost any natural or artificial composition of

airborne matter capable of being airborne. They may be in the form

of solid particles, liquid droplets, gases, or in combination thereof.

Generally, they fall into two main groups: (1) those emitted directly

from identifiable sources and (2) those produced in the air by

interaction between two or more primary pollutants, or by reaction

with normal atmospheric constituents, with or without

photoactivation. Exclusive of pollen, fog, and dust, which are of

natural origin, about 100 contaminants have been identified. Air

pollutants are often grouped in categories for ease in classification;

some of he categories are: solids, sulfur compounds, volatile organic

compounds, particulate matter, nitrogen compounds, oxygen

compounds, halogen compounds, radioactive compounds, and

odors. (EPA, December 1997)

air pollution: The presence of contaminants or pollutant

substances in the air that interfere with human health or welfare or

produce other harmful environmental effects. (EPA, December 1997)

air quality criteria: The levels of pollution and lengths of exposure

above which harmful health and welfare effects may occur. 

(EPA, December 1997) 

air quality standards: The level of pollutants prescribed by

regulations that are not to be exceeded during a given time in a

defined area. (EPA, December 1997)

air toxics: Air pollutants that cause or may cause cancer or other

serious health effects, such as reproductive effects or birth defects,

or adverse environmental and ecological effects. Examples of toxic air

pollutants include benzene, found in gasoline; perchloroethylene,

emitted from some dry cleaning facilities; and methylene chloride,

used as a solvent by a number of industries.

algal blooms: Sudden spurts of algal growth, which can degrade

water quality and indicate potentially hazardous changes in local

water chemistry. (EPA, December 1997)

ambient air: Any unconfined portion of the atmosphere; open air,

surrounding air. (EPA, December 1997)

ambient air quality standards: See criteria pollutants and National

Ambient Air Quality Standards.

animal waste: Byproducts that result from livestock, diary, and

other animal-related agricultural practices.

anthropogenic: Originating from humans, not naturally occurring.

(EPA, MAIA, August 2002)

aquatic ecosystems: Salt water or fresh water ecosystems, includes

rivers, streams, lakes, wetlands, estuaries and coral reefs.

aquifer: An underground geological formation, or group of

formations, containing water; source of ground water for wells and

springs. (USGS, 1996)

arsenic: A silvery, nonmetallic element that occurs naturally in rocks

and soil, water, air, and plants and animals. It can be released into the

environment through natural activities such as volcanic action,

erosion of rocks, and forest fires or through human actions.

Approximately 90 percent of industrial arsenic in the U.S. is used as

a wood preservative, but arsenic is also used in paints, dyes, metals,

drugs, soaps, and semiconductors. Agricultural applications (used in

rodent poisons and some herbicides), mining, and smelting also

contribute to arsenic releases in the environment. It is a known

human carcinogen.

arteriosclerosis: Hardening of the arteries.

asbestos: Naturally occurring strong, flexible fibers that can be

separated into thin threads and woven. These fibers resist heat and

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Appendix D Glossary of Terms D-3

chemicals and do not conduct electricity. Asbestos is used for

insulation, making automobile brake and clutch parts, and many

other products. These fibers break easily and form a dust composed

of tiny particles that are light and sticky. When inhaled or swallowed

they can cause health problems. (NCI, 2001)

assemblage: The association of interacting populations of

organisms in a selected habitat.

B

basal cell carcinoma: A type of skin cancer, usually curable if

treated in time.

beach day: A day that a beach would normally be open to the

public.

benthic: Occurring at or near the bottom of a body of water.

benthic organisms: The worms, clams, crustaceans, and other

organisms that live at the bottom of the estuaries and the sea.

benthos: In fresh water and marine ecosystems, organisms attached

to, resting on, or burrowed into bottom sediments.

bioaccumulation: A process whereby chemicals (e.g., DDT, PCBs)

are retained by plants and animals and increase in concentration

over time. Uptake can occur through feeding or direct absorption

from water or sediments. (EPA, MAIA, August 2002)

biodiversity: The variety and variability among living organisms and

the ecological complexes in which they occur. Diversity can be

defined as the number of different items and their relative

frequencies. The term encompasses three basic levels of biodiversity:

ecosystems, species, and genes.

biological diversity: See biodiversity.

biomarker: 1. A parameter that can be used to identify a toxic

effect in an individual organism and can be used in extrapolation

between species. 2. An indicator signaling an event or condition in a

biological system or sample and giving a measure of exposure, effect,

or susceptibility. (International Union of Pure and Applied Chemistry,

1993)

biomass: All of the living material in a given area; often refers to

vegetation. (EPA, December 1997)

biomonitoring: Use of a living organism or biological entity as a

detector and its response as a measure to determine environmental

conditions. Ambient biological surveys and toxicity tests are common

biological monitoring methods.

biotic: Refers to living organisms.

biotic condition: The state of living things.

biotic integrity: The ability to support and maintain balanced,

integrated functionality in the natural habitat of a given region. 

body burden: The amount of various contaminants retained in a

person’s tissues.

bog: A type of wetland that accumulates appreciable peat deposits.

Bogs depend primarily on precipitation for their water source and

are usually acidic and rich in plant residue, with a conspicuous mat

of living green moss. (EPA, December 1997)

brownfield: Real property, the expansion, redevelopment or reuse

of which may be complicated by the presence or potential presence

of a hazardous substance, pollutant, or contaminant.

C

cadmium: A metal found in natural deposits as ores containing

other elements. The greatest use of cadmium is primarily for metal

plating and coating operations, including transportation equipment,

machinery and baking enamels, photography, and television

phosphors. It is also used in nickel-cadmium and solar batteries and

in pigments. (EPA, OGWDW, September 2002)

carcinogen: An agent that causes cancer.

cerebrovascular disease: A category of diseases, including stroke,

related to blood vessels supplying the brain.

chlorination: The application of chlorine to drinking water, sewage,

or industrial waste to disinfect or to oxidize undesirable compounds.

(EPA, December 1997)

chlorine: A greenish-yellow gas that is slightly soluble in water.

Chlorine is often used in disinfection of water and treatment of

sewage effluent as well as in the manufacture of products such as

antifreeze, rubber, and cleaning agents.

chromium: A heavy metal that occurs naturally in rocks, plants, soil,

and volcanic dust and gases. It is tasteless and odorless. It can

damage living things at low concentrations and tends to accumulate

in the food chain. 
D-4 Glossary of Terms Appendix D

chronic exposure: Multiple exposures occurring over an extended

period of time or over a significant fraction of an animal’s or human’s

lifetime (usually seven years to a lifetime). (EPA, December 1997)

Class I area: Under the Clean Air Act, a Class I area is one in which

visibility is protected more stringently than under the national

ambient air quality standards; includes national parks, wilderness

areas, monuments, and other areas of special national and cultural

significance. (EPA, December 1997)

cleanup: Action taken to deal with a release or threat of release of a

hazardous substance that could affect humans, the environment, or

both. The term “cleanup” is sometimes used interchangeably with

the terms “remedial action,” “removal action,” “response action,” or

“corrective action.”

coastal and ocean ecosystem: An ecosystem that consists

primarily of estuaries and ocean waters under U.S. jurisdiction. U.S.

waters extend to the boundaries of the U.S. Exclusive Economic

Zone, 200 miles from the U.S. coast. (The Heinz Center, 2002)

(This report focuses on waters within 25 miles of the coast.)

coastal wetland: Ecosystem generally found along the Atlantic,

Pacific, Alaskan, and Gulf coasts and closely linked to the nation’s

estuaries, where sea water mixes with fresh water to form an

environment of varying salinities. The plants in coastal wetlands have

adapted to changing fluctuating water levels and salinities to create

tidal salt marshes, mangrove swamps, and tidal fresh water wetlands,

which form beyond the upper edges of tidal salt marshes where the

influence of salt water ends. Fresh water coastal wetlands can also be

found adjacent to the Great Lakes.

community water system: A public water system that serves at least

15 service connections used by year-round residents or regularly

serves at least 25 year-round residents. (EPA, December 1997)

composting: The controlled biological decomposition of organic

material in the presence of air to form a humus-like material.

Controlled methods of composting include mechanical mixing and

aerating, ventilating the materials by dropping them through a

vertical series of aerated chambers, and placing the them in piles out

in the open air and mixing it or turning it periodically.

congenital anomalies: Birth defects.

construction and demolition debris: Waste generated during

building, renovation, and wrecking projects. This type of waste

generally consists of materials such as wood, concrete, steel, brick,

and gypsum.

contaminant: Any physical, chemical, biological, or radiological

substance or matter that has an adverse effect on air, water, or soil.

(EPA, December 1997)

contaminated land: Ground that has been polluted with hazardous

materials and requires cleanup or remediation. Contaminated sites

may contain both polluted objects (e.g., buildings, machinery) and

land (e.g. soil, sediments, and plants). 

contaminated media: Materials such as soil, sediment, water, and

sludge that are polluted at levels requiring cleanup or further

assessment.

contamination: Introduction into water, air, or soil of

microorganisms, chemicals, toxic substances, wastes, or waste water

in a concentration that makes the medium unfit for its next intended

use. Also applies to surfaces of objects, buildings, and various

household and agricultural use products. (EPA, December 1997)

conterminous: Enclosed within one common boundary (e.g., the

48 conterminous states).

cotinine: A breakdown product (metabolite) of nicotine that can be

measured in urine.

criteria air pollutants: A group of six widespread and common air

pollutants regulated by the EPA on the basis of standards set to

protect public health or environmental effects of pollution. These six

criteria pollutants are carbon monoxide, lead, nitrogen dioxide,

ozone, particulate matter, and sulfur dioxide.

cropland: A National Resources Inventory land cover/use category

that includes areas used for the production of adapted crops for

harvest. Two subcategories of cropland are recognized: cultivated

and noncultivated. Cultivated cropland comprises land in row crops

or close-grown crops and also other cultivated cropland, for

example, hayland or pastureland that is in a rotation with row or

close-grown crops. Noncultivated cropland includes permanent

hayland and horticultural cropland. (USDA, NRCS, 2000)

D

depuration: The process of reducing the number of pathogenic

organisms that may be present in shellfish by using a controlled

aquatic environment as the treatment process. (FDA, 2000)

EPA’s Draft Report on the Environment 2003 n Technical Document
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Appendix D Glossary of Terms D-5

dermal absorption: The process by which a chemical penetrates

the skin and enters the body as an internal dose. (EPA, December

1997)

designated uses: Those water uses identified in state water quality

standards that must be achieved and maintained as required under

the Clean Water Act. Uses can include fishing, shellfish harvesting,

public water supply, swimming, boating, and irrigation. (EPA,

December 1997)

developed land: A combination of National Resource Inventory

land cover/use categories: large urban and built-up areas, small builtup areas, and rural transportation land. (USDA, NRCS, 2000)

dioxin: A group of chemically similar compounds, known chemically

as dibenzo-p-dioxins, that are created inadvertently during

combustion, chlorine bleaching of pulp and paper, and some types of

chemical manufacturing. Tests on laboratory animals indicate that it

is one of the more toxic anthropogenic (manmade) compounds. 

disinfection byproduct: A compound formed by the reaction of a

disinfectant such as chlorine with organic material in the water

supply; a chemical byproduct of the disinfection process. (EPA,

December 1997)

Dobson unit (DU): A measurement of ozone in the atmosphere. If,

for example, 100 DU of ozone were brought to earth’s surface, they

would form a layer one millimeter thick. (EPA, December 1997)

dose: 1. The actual quantity of a chemical administered to an

organism or to which it is exposed. 2. The amount of a substance

that reaches a specific tissue (e.g., the liver). 3. The amount of a

substance available for interaction with metabolic processes after

crossing the outer boundary of an organism. (EPA, December 1997)

dry deposition: The settling of gases and particles out of the

atmosphere. Dry deposition is a type of acid deposition, more

commonly referred to as “acid rain.” (EPA, Clean Air Markets Division,

October 2002). 

E

ecological indicators: Measurable characteristics related to the

structure, composition, or functioning of ecological systems (EPA,

SAB, 2002); a measure, an index of measures, or a model that

characterizes an ecosystem or one of its critical components

(Jackson et.al, 2000); any expression of the environment that

quantitatively estimates the condition of ecological resources, the

magnitude of stress, the exposure of biological components to

stress, or the amount of change in condition. (Barber, 1994)

ecological processes: The metabolic functions of ecosystems—

energy flow, elemental cycling, and the production, consumption,

and decomposition of organic matter, (EPA, SAB, 2002)

ecology: The study of the structure and function of nature; the

totality of relations between organisms and their environment.

(Odum, 1971)

ecoregions: Areas within which ecosystems with similar

characteristics are likely to occur with predictable patterns; variables

include such things as landform, vegetation, soils, and fauna.

ecosystem: 1. The interacting system of a biological community and

its nonliving environmental surroundings. 2. A geographic area

including all living organisms (people, plants, animals, and

microorganisms), their physical surroundings (such as soil, water and

air), and the natural cycles that sustain them. 

ecotone: A habitat created by the juxtaposition of distinctly

different habitats; an edge habitat; or an ecological zone or

boundary where two or more ecosystems meet. (EPA, December

1997)

emissions standard: The maximum amount of air-polluting

discharge legally allowed from a single source, mobile or stationary.

(EPA, December 1997)

endangered species: Animals, birds, fish, plants, or other living

organisms threatened with extinction by anthropogenic

(human-caused) or natural changes in their environment.

Requirements for declaring a species “endangered” are contained in

the Endangered Species Act. (EPA, December 1997)

endocrine disruptors: Chemicals that interfere with the endocrine

systems, leading to adverse effects. Some chemicals do this by

binding to receptors, such as the estrogen and androgen receptors. 

endocrine system: The components of the body that produce

hormones that regulate reproductive and developmental functions.

Major endocrine glands include the pituitary, thyroid, adrenal glands,

testes, and ovaries.

enrichment: The addition of nutrients (e.g. nitrogen, phosphorus,

carbon compounds) from sewage effluent, agricultural or urban

runoff, or other sources to surface water. Enrichment greatly

increases the growth potential for algae and other aquatic plants.

(EPA, December 1997)

environmental burden of disease: The proportion of diseases,

disability, and injury caused by factors in the environment: chemical

pollutants, infectious microorganisms, and radiation.
D-6 Glossary of Terms Appendix D

environmental exposure: Human exposure to pollutants in their

surroundings. Low-level chronic exposure to pollutants is one of the

most common forms of environmental exposure (see threshold level).

(EPA, December 1997)

environmental indicators: Scientific measurements that help

measure over time the state of air, water, and land resources,

pressures on those resources, and resulting effects on ecological and

human health. Indicators show progress in making the air cleaner and

the water purer and in protecting land. 

environmental risk: The potential for adverse effects on living

organisms associated with pollution of the environment by effluents,

emissions, wastes, or accidental chemical releases; energy use, or the

depletion of natural resources. (EPA, December 1997)

environmental risk factor: An exposure to something in the

environment that, based on evidence, is known to be associated with

health-related conditions and considered important to prevent.

(Green, 1999)

environmental tobacco smoke: A mixture of smoke exhaled by a

smoker and the smoke from the burning end of a smoker’s cigarette,

pipe, or cigar. Also known as second hand smoke.

epidemiology: The study of how diseases occur in a population

or area.

epiphyte: A plant, fungus, or microbe sustained entirely by

nutrients and water received, by means other than a parasite, from

within the canopy in which it resides. (Moffett, 2000)

erosion: The wearing away of land surface by wind or water,

intensified by land-clearing practices related to farming, 

residential or industrial development, road building, or logging. 

(EPA, December 1997)

estuaries: Partially enclosed bodies of water (this term includes

bays, sounds, lagoons, and fjords); they are generally considered to

begin at the upper end of tidal or saltwater influence and end where

they meet the ocean. (The Heinz Center, 2002)

eutrophic: Pertaining to a lake or other body of water

characterized by large nutrient concentrations, resulting in high

productivity of algae. 

eutrophication: The slow aging process during which a lake,

estuary, or bay evolves into a bog or marsh and eventually

disappears. During the later stages of this process, the water body is

choked by abundant plant life that result from higher levels of

nutritive compounds such as nitrogen and phosphorus. Human

activities can accelerate the process. (EPA, December 1997)

exotic species: A species that is not indigenous to a region. (EPA,

December 1997)

exposure: The amount of radiation or pollutant present in a given

environment that represents a potential health threat to living

organisms. (EPA, December 1997)

exposure pathway: The path from sources of pollutants via, soil,

water, or food to humans and other species. (EPA, December 1997)

exposure route: The way a chemical or pollutant enters an

organism after contact; i.e. by ingestion, inhalation, or dermal

absorption. (EPA, December 1997)

extraction waste: Byproducts produced as a result of mining

practices.

F

farmlands: Include both croplands-lands used for production of

annual and perennial crops and livestock-and surrounding landscape,

such as field borders and windbreaks, small woodlots, grassland or

shrubland areas, wetlands, farmsteads, small villages and other builtup areas, and similar areas within and adjacent to croplands. (The

Heinz Center, 2002) 

fauna: Animal life.

fertilizers: Supplements to improve plant growth that are commonly

used on agricultural lands, as well as in urban, industrial, and

residential settings.

fish kill: A large-scale die-off of fish caused by factors such as

pollution, noxious algae, harmful bacteria, and hypoxic conditions.

floodplain: Any land area susceptible to being inundated by water

from any source.

flora: Plant or bacterial life.

forage: Food for animals especially when taken by browsing or grazing.

forests: Lands at least 10 percent covered by trees of any size, at

least one acre in extent. This includes areas in which trees are

intermingled with other cover, such as chaparral and pinyon, juniper

areas in the Southwest, and both naturally regenerating forests and

areas planted for future harvest (plantations or “tree farms”). (The

Heinz Center, 2002)

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Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix D Glossary of Terms D-7

forest fragmentation: The division of a formerly healthy forest into

patches, usually as a result of conversion to agricultural or residential

land. (EPA, August 2002)

forest land: Land that is at least 10 percent stocked by forest

trees of any size, including land that formerly had tree cover and

that will be naturally or artificially regenerated. The minimum area

for classification of forest land is one acre. (USDA, Forest Service,

April 2001)

fresh water systems: Include: 

Q Rivers and streams, including those that flow only part of the year 

Q Lakes, ponds, and reservoirs, from small farm ponds to the Great

Lakes 

Q Ground water, which is often directly connected to rivers, streams,

lakes, and wetlands 

Q Fresh water wetlands, including forested, shrub, and emergent wetlands (marshes), and open water ponds 

Q Riparian areas–they usually vegetated margins of streams and

rivers (although this term can also apply to lake margins). 

(The Heinz Center, 2002)

G

geomorphology: The scientific study of the nature and origin of

the landforms on the surface of earth and other planets.

giardiasis: The illness resulting from infection of the gastrointestinal

tract with Giardia lamblia. The symptoms of giardiasis include gastric

pain, fatigue, extreme diarrhea, fever, chills, and nausea. The most

acute symptoms typically last only a few days (Garcia, 1999).

global burden of disease: The overall impact of disease related to

all causes. It takes into account the burden represented by years of

life lived with illness or disability.

grasslands and shrublands: Lands in which the dominant

vegetation is grasses and other nonwoody vegetation, or where

shrubs (with or without scattered trees) are the norm (also called

rangelands); includes bare-rock deserts, alpine meadows, arctic

tundra, pastures, and haylands (an overlap with the farmland

system). Less-managed pastures and haylands fit well within the

grassland/shrubland system; more heavily managed ones fit well as

part of the farmlands system. (The Heinz Center, 2002) 

gross primary production: Total energy captured in units of

carbon gain.

ground-level ozone: See ozone.

ground water: Subsurface water that occurs beneath the water

table in soils and geologic formations that are fully saturated. 

H

habitat: The place where a population (e.g., human, animal, plant,

microorganism) lives and its surroundings, both living and nonliving.

(EPA, December 1997)

habitat fragmentation: The division of large areas of natural

habitat into smaller sections through conversion of the natural

habitat to other uses (e.g., roads, development), resulting in

populations of plants and animals becoming isolated from each other

and potentially threatening their survival.

habitat loss: The destruction of habitat by natural disasters

(hurricanes, fires, flooding, etc.) and human activity (clearing land for

agricultural, industrial, and residential development; clear-cut

harvesting of timber; oil spills; and war).

halogens: Compounds that contain atoms of chlorine, bromine, or

fluorine.

hardwood: The wood of an angiospermous tree as distinguished

from that of a coniferous tree; a tree that yields hardwood.

hazardous waste: Byproducts of society that can pose a

substantial or potential threat to human health or the environment

when improperly managed. Hazardous waste possesses at least one

of four characteristics: ignitability, corrosivity, reactivity, or toxicity.

health outcomes: An outcome measured by the quality of life,

likelihood of disease, life expectancy, and overall health of individuals

or communities. (HIC, 2000-2001)

heavy metals: Metallic elements with high atomic weights 

(e.g., mercury, chromium, cadmium, arsenic, lead); can damage living

things at low concentrations and tend to accumulate in the food

chain. (EPA, December 1997)

herbicide: A form of pesticide used to control weeds that limit or

inhibit the growth of the desired crop.

high-level radioactive waste: Highly radioactive waste material from

the chemical processing of spent fuel. It includes spent fuel, liquid

waste, and highly radioactive solid waste from the liquid. High-level

radioactive waste contains elements that decay very slowly and

remain radioactive for thousands of years. (DOE, 1997)
EPA’s Draft Report on the Environment 2003 Q Technical Document

D-8 Glossary of Terms Appendix D

household hazardous waste: Hazardous products used and

disposed of by residential rather than industrial consumers. It

includes paints, stains, varnishes, solvents, pesticides, and other

materials or products containing volatile chemicals that can catch

fire, react, or explode, or are corrosive or toxic. 

human exposure to contaminants: The contact of a chemical

contacting and the outer boundary of a human. (EPA, ORD, 

March 1998)

hydrologic cycle: Movement or exchange of water between the

atmosphere and earth. (EPA, December 1997)

hydrologic unit code (HUC): An eight-digit code that is used to

classify watersheds in the U.S. This code uniquely identifies each of

four levels of watershed classification within four two-digit fields. The

first two digits of the code identify the water-resources region; the

first four digits identify the sub-region; the first six digits identify the

accounting unit; and the final two digits identify the cataloging unit.

For example, in hydrologic unit code (HUC) 01080204, 01 identifies

the region; 0108 identifies the sub-region; 010802 identifies the

accounting unit; and 01080204 identifies the cataloging unit. 

hydrology: The geology of ground water, with particular emphasis

on the chemistry and movement of water. (EPA, December 1997)

hypertrophic: Pertaining to a lake or other body of water

characterized by excessive nutrient concentrations, resulting high

productivity. 

hypoxia/hypoxic waters: Waters with low levels of dissolved

oxygen concentrations, typically less than two ppm, the level

generally accepted as the minimum required for most marine life to

survive and reproduce. (EPA, December 1997).

I

impervious surface: A hard surface area that either prevents or

retards the entry of water into the soil mantle or causes water to run

off the surface in greater quantities or at an increased rate of flow.

Common impervious surfaces include, but are not limited to,

rooftops, walkways, patios, driveways, parking lots, storage areas,

concrete or asphalt paving, and gravel roads. (Washington

Department of Ecology, 1992).

impounded: Refers to a body of water such as a pond, lake, or river

that has been confined by a dam, dike, floodgate, or other barrier.

(Texas Environmental Center, 1991)

incidence rate of disease: The number of new cases of a disease or

condition in a given period of time in a specified population.

indoor air: The breathable air inside a habitable structure or

conveyance. (EPA, December 1997)

indoor air pollution: Chemical, physical, or biological contaminants

in indoor air. (EPA, December 1997)

industrial waste: Process waste associated with manufacturing.

This waste usually is not classified as either municipal waste or

RCRA hazardous waste by federal or state laws. (EPA, OSWER,

October 1988) 

industrial non-hazardous waste: Process waste associated with

generation of electric power and manufacture of materials such as

pulp and paper, iron and steel, glass, and concrete. This waste

usually is not classified as either municipal waste or hazardous waste

by federal or state laws. 

infant mortality: The death of children in the first year of life.

inland wetlands: Wetlands that include marshes, wet meadows, and

swamps. These areas are often dry one or more seasons every year.

In the arid West of the U.S., they may be wet only periodically.

integrated pest management: The coordinated use of available

pest-control methods to prevent unacceptable levels of pest damage

by the most economical means and with the least possible hazard to

people, property, and the environment.

invasive species/invasive nuisance species: See nonnative species.

inversion: The condition that occurs when warm air is trapped near

the ground and normal temperature gradients don’t permit air to

flow into the atmosphere. (Nadakavukaren, 2000).

J

Julian day (JD): A Julian day is a continuous count of days

beginning with January 1, 4713 BC. Julian days are often used by

astronomers and sometimes used by historians to provide a precise

date for an event, independent of all calendar systems. The date

4713 BC was chosen for the start of the count because this was

earlier than all known historical records and happened to be a

convenient starting point for several chronological and astronomical

cycles. The length of the year in the Julian calendar is exactly

365.25 Julian days. 
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix D Glossary of Terms D-9

K

keystone species: A species that interacts with a large number of

other species in a community. Because of the interactions, the

removal of this species can cause widespread changes to community

structure. (Pidwirny, 2000-2001) 

L

lagoons (for waste treatment): Water impoundments in which

organic wastes are stored, stabilized, or both. A shallow, artificial

treatment pond where sunlight, bacterial action, and oxygen work to

purify wastewater; a stabilization pond. An aerated lagoon is a

treatment pond that uses oxygen to speed up the natural process of

biological decomposition of organic wastes. (EPA, August 2002)

land cover: The ecological status and physical structure of the

vegetation on the land surface. (NRC, 2000)

land use: Describes how a piece of land is managed or used by

humans. The degree to which the land reflects human activities (e.g.,

residential and industrial development, roads, mining, timber

harvesting, agriculture, grazing, etc.).

landfills: 1. Sanitary landfills: Disposal sites for nonhazardous solid

wastes spread in layers, compacted to the smallest practical volume,

and covered by material applied at the end of each operating day. 2.

Secure chemical landfills: Disposal sites for hazardous waste, selected

and designed to minimize the chance of release of hazardous

substances into the environment.

landscape: The traits, patterns, and structure of a specific

geographic area, including its biological composition, its physical

environment, and its anthropogenic or social patterns. An area where

interacting ecosystems are grouped and repeated in similar form.

(EPA, December 1997)

landscape condition: The extent, composition, and patterns of

habitats in a landscape.

landscape pattern: The spatial distribution of the land use/land

cover types, the arrangement of patches, connectivity among

patches, and corridors for movement.

large urban and built-up areas: A National Resources Inventory

land cover/use category composed of developed tracts of at least

10 acres, meeting the definition of urban and built-up areas. (USDA,

NRCS, 2000)

large-quantity generators: Businesses that generate substantial

“RCRA hazardous waste” as a part of their regular activities.

leaching: The process by which soluble materials in the soil, such as

nutrients, pesticide chemicals, or contaminants, are washed into a

lower layer of soil or are dissolved and carried away by water. (Texas

Environmental Center, 1991)

lead: A heavy metal used in many materials and products. It is a

natural element and does not break down in the environment. When

absorbed into the body, it can be highly toxic to many organs and

systems.

levee: A natural or manmade earthen barrier along the edge of a

stream, lake, or river. Land alongside rivers can be protected from

flooding by levees.

lichen: Any of numerous complex thallophytic plants made up of an

alga and a fungus growing in symbiotic association on a solid surface

(e.g., a rock). 

life expectancy: The probable number of years (or other time

period) that members of a particular age class of a population are

expected to live, based on statistical studies of similar populations in

similar environments. 

life expectancy (at birth): The average number of years that a

group or cohort of infants born in the same year are expected to live.

low birthweight: Refers to children born weighing less than 2,500

grams (5.5 pounds).

low-level waste: Radioactive waste, including accelerator-produced

waste, that is not high-level radioactive waste, spent nuclear fuel,

transuranic waste, byproduct material (as defined in the Atomic

Energy Act of 1954), or naturally occurring radioactive material. 

M

macroinvertebrate: An organism that lacks a backbone and can be

seen with the naked eye. (EPA, OW, November 2002).

malignant melanoma: A type of skin cancer, more often fatal than

other types of skin cancer.

media: Specific environments—air, water, soil—that are the subject

of regulatory concern and activities. (EPA, December 1997)
D-10 Glossary of Terms Appendix D

medical waste: Any solid waste generated during the diagnosis,

treatment, or immunization of human beings or animals, in research,

production, or testing. 

mercury: Mercury is a metallic element that occurs in many forms

and in combination with other elements. When combined with

carbon, which readily occurs in water, it forms more-bioavailable

organic mercury compounds (e.g., methylmercury).

mesotrophic: Pertaining to a lake or other body of water

characterized by moderate nutrient concentrations and moderate

productivity in terms of aquatic animal and plant life. 

metabolic rate: The rate at which the body can turn food into

energy.

metabolites: Compound that result from human digestion

(metabolism) of contaminants and that serve as a biomarkers of

exposure. 

metadata: Information about data. It describes the content, quality,

condition, and other characteristics of data. 

methemoglobinemia: A rare but potentially fatal condition in

infants that results from interferences in the blood’s ability to carry

oxygen. Nitrates in drinking water are associated with

methemoglobinemia (also known as “blue baby syndrome”). 

metropolitan area: A Metropolitan Area (MA) is a U.S. Census

Bureau construct that consists of an area comprising a core with a

large population nucleus, together with adjacent communities that

have a high degree of economic and social integration with that core.

Each MA must contain either a place with a minimum population of

50,000 or a Census Bureau-defined urbanized area and a total MA

population of at least 100,000 (75,000 in New England). The area

is defined by county boundaries. (U.S. Census Bureau, 2001)

microorganisms: Tiny life forms that can be seen only with the aid

of a microscope. Some microorganisms can cause acute health

problems when consumed; also known as microbes. (EPA, OGWDW,

November 2002)

Mid-Atlantic Highlands: A region that encompass 79,000 square

miles and extends east to west from the Blue Ridge Mountains in

Virginia to the Ohio River, and north to south from the Catskill

Mountains to the North Carolina-Tennessee-Virginia border

mixed low-level waste: Low-level radioactive waste that also

contains hazardous constituents. (DOE, December 1999)

mobile sources: Moving objects that release pollution from

combustion of fossil fuels, such as cars, trucks, buses, planes, trains,

lawn mowers, construction equipment, and snowmobiles. Some

mobile sources, such as some construction equipment or movable

diesel generators, are called nonroad sources, because they are

usually operated off road. 

Monte Carlo analysis: A computer-based statistical tool—drawing

on various probabilistic techniques—that is used to help quantify

variability and uncertainty inherent to risk assessment. 

morbidity: Sickness, illness, or disease that does not result in

death.

mortality: Death; death rate, the proportion of the population who

die of a disease, often expressed as a number per 100,000.

municipal solid waste: Waste discarded by households,

hotels/motels, and commercial, institutional, and industrial sources.

It typically consists of everyday items such as product packaging,

grass clippings, furniture, clothing, bottles, food scraps, newspapers,

appliances, paint, and batteries. It does not include waste water.

N

National Ambient Air Quality Standards: Standards established

by EPA under the Clean Air Act that apply to outdoor air throughout

the country (see criteria pollutants). (EPA, December 1997)

nematodes: Simple worms consisting of an elongate stomach and

reproduction system inside a resistant outer cuticle (outer skin).

(USDA, 2001)

net primary production: Gross primary production minus all

sources of plant respiration. Represents the carbon or biomass that

is available to other organisms, providing the base of the food web.

nitrate: The primary chemical form of nitrogen in most aquatic

systems; occurs naturally; a plant nutrient and fertilizer; can be

harmful to humans and aninmals.

nitric oxide (NO): A gas formed by combustion under high

temperature and high pressure in an internal combustion engine; it is

converted by sunlight and photochemical processes in ambient air to

nitrogen oxide. NO is a precursor of ground-level ozone pollution, or

smog. (EPA, December 1997)

nitrogen dioxide (NO2): The result of nitric oxide combining with

oxygen in the atmosphere; major component of photochemical

smog. (EPA, December 1997)

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Appendix D Glossary of Terms D-11

nitrogen export: The annual quantity of total nitrogen produced

by nitrogen sources in a watershed that leaves the watershed

through a river or stream that connects to other watersheds

downstream

nitrogen oxide (NOX): The result of photochemical reactions of

nitric oxide in ambient air; major component of photochemical smog.

Product of combustion from transportation and stationary sources

and a major contributor to the formation of ozone in the

troposphere and to acid deposition. (EPA, December, 1997)

noncommunity water system: A public water system that is not a

community water system. Nontransient noncommunity water systems

are those that regularly supply water to at least 25 of the same

people at least six months per year but not year-round (e.g.,

schools, factories, office buildings, and hospitals that have their own

water systems). Transient noncommunity water systems provide water

in a place where people do not remain for long periods of time (e.g.,

a gas station or campground).

nonhazardous waste: See solid waste.

nonisolated intermediaries: An intermediate compound in a

chemical manufacturing process that can be a by-product or can be

released as a result of the process.

nonnative species: A species that has been introduced by human

action, either intentionally or by accident, into areas outside its

natural geographical range. Other names for these species include

alien, exotic, introduced, and nonindigenous. 

nonpoint source pollution: Pollution that occurs when rainfall,

snowmelt, or irrigation water runs over land or through the ground,

picks up pollutants, and deposits them into rivers, lakes, coastal

waters, or ground water. Types of pollution include sediments,

nutrients, pesticides, pathogens (bacteria and viruses), toxic

chemicals, heavy metals that runoff from agricultural land, urban

development, and roads. 

noxious algae: Toxic algae commonly associated with harmful algae

blooms such as red tides.

nutrient: Any substance assimilated by living things that promotes

growth. The term is generally applied to nitrogen and phosphorus,

but is also applied to other essential and trace elements. 

nutrient enrichment: See eutrophication.

O

oil and gas production wastes: Drilling fluids, produced waters,

and other wastes associated with the exploration, development, and

production of crude oil or natural gas that are conditionally

exempted from regulation as hazardous wastes. 

oligotrophic: Pertaining to a lake or other body of water

characterized by extremely low nutrient concentrations, often with

very limited plant growth but with high dissolved-oxygen levels. 

organic matter: Plant and animal material that is in the process of

decomposing. When it has fully decomposed, it is called “humus.”

This humus is important for soil structure because it holds individual

mineral particles together in clusters. (USDA, NRCS, 2000)

organophosphate: Pesticides that contain phosphorus; short-lived,

but some can be toxic when first applied. (EPA, December, 1997)

outer boundary: In reference to the body, includes skin and body

openings.

ozone (O3): A very reactive form of oxygen that is a bluish

irritating gas of pungent odor. It is formed naturally in the

atmosphere by a photochemical reaction and is a beneficial

component of the upper atmosphere. It is also a major air pollutant

in the lower atmosphere, where it can form by photochemical

reactions when there are conditions of air pollutants, bright sunlight,

and stagnant weather.

ozone depletion: Destruction of the stratospheric ozone layer,

which shields earth from ultraviolet radiation harmful to life. This

destruction of ozone is caused by the breakdown of certain

compounds that contain chlorine, bromine, or both

(chlorofluorocarbons or halons), which occurs when they reach the

stratosphere and then catalytically destroy ozone molecules. (EPA,

December 1997)

ozone hole: A well-defined, large-scale area of significant thinning

of the ozone layer. It occurs over Antarctica each spring. 

ozone layer: The protective stratum in the atmosphere, about 15

miles above the ground, that absorbs some of the sun’s ultraviolet

rays, thereby reducing the amount of potentially harmful radiation

that reaches earth’s surface. (EPA, December 1997)

ozone precursors: Chemicals that contribute to the formation 

of ozone.
D-12 Glossary of Terms Appendix D

P

particulate matter: Solid particles or liquid droplets suspended

or carried in the air (e.g., soot, dust, fumes, mist). (EPA, OAR,

October 2002)

passive smoking: Exposure to tobacco smoke, or the chemicals in

tobacco smoke, without actually smoking. It usually refers to a

situation where a nonsmoker inhales smoke emitted into the

environment by other people smoking. This smoke is known as

“environmental tobacco smoke” (ETS). (National Public Health

Partnership, 2000)

pastureland: A National Resources Inventory land cover/use

category of land managed primarily for the production of introduced

forage plants for livestock grazing. Pastureland cover may consist of a

single species in a pure stand, a grass mixture, or a grass-legume

mixture. For the NRI, it includes land that has a vegetative cover of

grasses, legumes, and/or forbs, regardless of whether or not it is

being grazed by livestock. (USDA, NRCS, 2000).

pathogen: Microorganism (e.g., bacteria, viruses, or parasites)

that can cause disease in humans, animals, and plants. (EPA,

December 1997)

periphyton: Microscopic underwater plants and animals that are

firmly attached to solid surfaces such as rocks, logs, and pilings.

(EPA, December 1997)

persistent organic pollutants: Chemicals that endure in the

environment and bioaccumulate as they move up trough the food

chain. They include organochlorine pesticides, polychlorinated

biphenyls (PCBs), dioxins, and furans.

pesticides: Any substance or mixture of substances intended to

prevent, destroy, repel, or mitigate any pest. Pests can be insects,

mice and other animals, unwanted plants (weeds), fungi, or

microorganisms such as bacteria and viruses. Though often

misunderstood to refer only to insecticides, the term “pesticide” also

applies to herbicides, fungicides, and various other substances used

to control pests. Under U.S. law, a pesticide is also any substance or

mixture of substances intended for use as a plant regulator, defoliant,

or desiccant. 

phosphorus: An essential chemical food element that can

contribute to the eutrophication of lakes and other water bodies.

Increased phosphorus levels result from discharge of

phosphorus-containing materials into surface waters. (EPA,

December 1997)

photosynthesis: The manufacture by plants of carbohydrates and

oxygen from carbon dioxide mediated by chlorophyll in the presence

of sunlight. (EPA, December 1997)

phytoplankton: That portion of the plankton community composed

of tiny plants (e.g. algae, diatoms). (EPA, December 1997)

playas: Areas at the bottom of undrained desert basins that are

sometimes covered with water. (EPA, OWOW, July 2002)

PM2.5: Fine particles that are less than or equal to 2.5 micrometers

in diameter.

PM10: Particles less than or equal to 10 micrometers in diameter.

point source pollution: Effluent or discharges directly from a

pipe into a waterway (e.g., from many industries and sewage

treatment plants).

pollutant: Generally, any substance introduced into the environment

that adversely affects the usefulness of a resource or the health of

humans, animals, or ecosystems. (EPA, December 1997)

pollution: Generally, the presence of a substance in the environment

that, because of its chemical composition or quantity, prevents the

functioning of natural processes and produces undesirable

environmental and health effects. Under the Clean Water Act, for

example, the term has been defined as the manmade or man-induced

alteration of the physical, biological, chemical, and radiological integrity

of water and other media. (EPA, December 1997)

polychlorinated biphenyls (PCBs): A group of synthetic chemicals

that can exist as oily liquids and waxy solids. Due to their

non-flammability, chemical stability, high boiling point and electrical

insulating properties, PCBs were used in hundreds of industrial and

commercial applications including electrical, heat transfer, and

hydraulic equipment; as plasticizers in paints, plastics and rubber

products; in pigments, dyes and carbonless copy paper, and many

other applications. PCBs can produce toxic effects and are probable

carcinogen. (EPA, OPPT, February 2003)

pressure: See stressor.

prevalence of disease: That part of the total population affected

by a condition or disease.

prevalence rate: The total number of persons with a given disease

or condition in a specified population at a specified period of time.

production capacity: Chlorophyll per unit area for terrestrial

ecosystems (including wetlands and riparian areas) and per unit

volume for aquatic ecosystems.

productivity: The rate at which ecosystems use energy (principally

solar energy) to fix atmospheric carbon dioxide. (NRC, 2000)

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Appendix D Glossary of Terms D-13

R

radioactive waste: Garbage, refuse, sludge, and other discarded

material, including solid, liquid, semisolid, or contained gaseous

material that must be managed for its radioactive content (DOE, July

1999). Types of radioactive waste include high-level waste, spent

nuclear fuel, transuranic waste, low-level waste, mixed low-level waste,

and contaminated media. 

radon (Rn-222): A naturally occurring radioactive gas that has no

color, odor, or taste and is chemically inert. Radon comes from the

radioactive decay of uranium in soil, rock, and ground water and is

found all over the U.S. It has a half-life of 3.8 days, emitting ionizing

radiation (alpha particles) during its radioactive decay to several

radioactive isotopes known as “radon decay products.” It gets into

indoor air primarily from soil under homes and other buildings.

Radon is a known human lung carcinogen and represents the largest

fraction of the public’s exposure to natural radiation.

rangelands: A National Resources Inventory land cover/use

category on which the climax or potential plant cover is composed

principally of native grasses, grasslike plants, forbs or shrubs

suitable for grazing and browsing, and introduced forage species

that are managed like rangeland. This would include areas where

introduced hardy and persistent grasses, such as crested

wheatgrass, are planted and such practices as deferred grazing,

burning, chaining, and rotational grazing are used, with little or no

chemicals or fertilizer being applied. Grasslands, savannas, many

wetlands, some deserts, and tundra are considered to be

rangeland. Certain communities of low forbs and shrubs, such as

mesquite, chaparral, mountain shrub, and pinyon-juniper, are also

included as rangeland. (USDA, NRCS, 2000). 

rare and at-risk species: Rare species are those that are

particularly vulnerable to both human-induced threats and natural

fluctuations and hazards. At-risk species are those classified by the

Association for Biodiversity Information as vulnerable or more rare.

RCRA hazardous waste: Applies to certain types of hazardous

wastes that appear on EPA’s regulatory listing (RCRA) or that exhibit

specific characteristics of ignitability, corrosiveness, reactivity, or

excessive toxicity.

red tide: A common name for the phenomenon where certain

phytoplankton species contain reddish pigments and “bloom” such

that the water appears to be colored red.

regional and continental areas: Heterogeneous areas at regional

(e.g, Southeast) and continental scales composed of a cluster or

mosaic of interacting ecosystems. Regional and continental

ecosystems are not characterized primarily by a dominant land cover

type such as forests, farmlands, grasslands or urban areas, but rather

include many or all these ecosystems at these larger spatial scales.

Regional and continental ecosystems reflect the underlying

landscape patterns at these larger scales.

relative risk: A measurement of the chance of contracting a disease

in those who have been exposed to a risk factor compared with the

risk for those who have not been exposed.

remediation: Cleanup or other methods used to remove or contain

a toxic spill or hazardous materials from a contaminated site. 

reserved forest land: Forested land withdrawn from timber

utilization through statute, administrative regulation, or designation.

(USDA, Forest Service, April 2001)

richness: A measure of species diversity, which usually decreases

with impairment. It is based on the number of distinct taxa (at a level

selected to identify, e.g., order, family, species); can be the total

number of taxa, or the number in an identified group (e.g., number

of mayfly taxa). 

rill: A small channel eroded into the soil by surface runoff; can be

easily smoothed out or obliterated by normal tillage. (EPA,

December 1997)

riparian area: The area adjacent to streams and rivers, important as

buffers to runoff. Many riparian areas include wetlands.

riparian wetland: A wetland along a stream or river.

riparian zone: A 30-meter buffer on each side of a stream or river.

risk: The probability that a health problem, injury, or disease 

will occur. 

risk factor: A characteristic (e.g., race, sex, age, obesity) or variable

(e.g., smoking, occupational exposure level) associated with

increased probability of an adverse effect. (EPA, December 1997)

runoff: That part of precipitation, snowmelt, or irrigation water that

runs off the land into streams or other surface water. It can carry

pollutants from the air and land into receiving waters. (EPA,

December 1997)

rural transportation land: A National Resources Inventory land

cover/use category that consists of all highways, roads, railroads,

and associated right-of-ways outside urban and built-up areas;

including private roads to farmsteads or ranch headquarters,

logging roads, and other private roads, except field lanes. (USDA,

NRCS, 2000)
D-14 Glossary of Terms Appendix D

S

secondhand smoke: See environmental tobacco smoke.

sediment transport: The movement of sediment in rivers and

streams.

sedimentation: the process of forming or depositing sediment;

letting solids settle out of wastewater by gravity during treatment.

self-supplied water: Water not drawn from the public water supply.

silica: An inorganic compound mined from the earth; has been

found to be associated with lung cancer (Steenland, 1997). Silica is

used in foundries, pottery making, brick making, and sand blasting. 

silviculture: The science of producing and tending a forest; the

theory and practice of controlling forest establishment, composition,

and growth. (Matthews, 1989)

sludge: Solid, semisolid, or liquid waste generated from a municipal,

commercial, or industrial waste water facility. 

small built-up areas: A National Resources Inventory land

cover/use category consisting of developed land units of 0.25 to

10 acres, which meet the definition of urban and built-up areas.

(USDA, NRCS, 2000)

smart growth: The management of “urbanization” that seeks to

serve the economy, the community, and the environment. Smart

growth seeks to foster healthy communities, a clean environment,

economic development and jobs, and strong neighborhoods with a

range of housing options.

softwood: Coniferous trees, usually evergreen, that have needles or

scale-like leaves. (USDA, Forest Service, November 2002)

solid waste: Nonliquid, nonsoluble materials ranging from municipal

garbage to industrial wastes that contain complex and sometimes

hazardous substances. Solid wastes also include sewage sludge,

agricultural refuse, demolition wastes, mining residues, and liquids

and gases in containers. (EPA, December 1997)

species richness: The absolute number of species in an assemblage

or community.

spent nuclear fuel: Nuclear reactor fuel that has been used to the

extent that it can no longer effectively sustain a chain reaction. (EPA,

December 2002)

spray drift: The physical movement of a pesticide through air at the

time of application, or soon thereafter, to any site other than that

intended for application.

sprawl: See urban sprawl.

squamous cell carcinoma: A type of skin cancer, usually curable if

treated in time.

stationary source: A place or object from which pollutants are

released and that stays in one place. These sources include many

types of facilities, including power plants, gas stations, dry cleaners,

incinerators, factories, and houses.

stressor: A physical, chemical, or biological entity that can induce

adverse effects on ecosystems or human health. (EPA, December 1997)

submerged aquatic vegetation (SAV): Rooted vegetation that

grows under water in shallow zones where light penetrates. (EPA,

CBP, October 2002)

Superfund: The program operated under the legislative authority of

the Comprehensive Environmental Response, Compensation, and

Liability Act (CERCLA) and the Superfund Amendments and

Reauthorization Act (SARA) that funds and carries out EPA solid

waste emergency and long-term removal and remedial activities.

These activities include establishing the National Priorities List,

investigating sites for inclusion on the list, determining their priority,

and conducting and/or supervising cleanup and other remedial

actions. (EPA, December 1997)

Superfund site: Any land in the U.S. that has been contaminated

by hazardous waste and identified by EPA as a candidate for cleanup

because it poses a risk to human health, the environment, or both. 

surface eythemal: Sun-burning UV radiation at earth=s surface.

surface water: Water in rivers, streams, lakes, ponds, reservoirs,

estuaries, and wetlands (found at the surface, in contrast to

ground water).

sustainability: Long-term management of ecosystems to meet the

needs of present human populations without interruption,

weakening, or loss of the resource base for future generations.

(Environment Canada, 1997) 

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Appendix D Glossary of Terms D-15

T

thermoelectric water use: Use of water for cooling in the

generation of electric power.

threatened and endangered species: Those species that are in

danger of extinction throughout all or a significant portion of their

range or are likely to become endangered in the future. (Grondahl,

et al, July 1997) 

threshold: 1.The lowest dose of a chemical at which a specified

measurable effect is observed and below which it is not observed.

2.The dose or exposure level below which a significant adverse effect

is not expected. (EPA, December 1997)

timber land: Forest land that is capable of producing crops of

industrial wood (at least 20 cubic feet per acre per year in natural

stands) and not withdrawn from timber use by statute or

administrative regulation. (USDA, Forest Service, April 2001)

total off-site releases: The total annual amount (in pounds) of a

toxic chemical transferred from a facility to publicly owned treatment

works (POTW) or to an off-site location (non-POTW). (EPA, TRI,

November 2002)

total on-site releases: The total annual release quantities (in

pounds) of a chemical to air, water, on-site land, and underground

injection wells. (EPA, TRI, November 2002)

Toxics Release Inventory (TRI): A publicly available EPA database

that contains information on toxic chemical releases and other waste

management activities reported annually by certain covered

industries and federal facilities. TRI was established under the

Emergency Planning and Community Right-to-Know Act of 1986

(EPCRA) and expanded by the Pollution Prevention Act of 1990.

(EPA, TRI, December 2002)

toxic substance: Any substance that presents a significant risk of

injury to health or the environment through exposure.

toxic waste: A waste that can produce injury if inhaled, swallowed,

or absorbed through the skin. (EPA, December 1997)

transuranic waste: A category of radioactive waste. It contains

elements that have atomic numbers higher than uranium (92), such

as plutonium; results primarily from past nuclear weapons production

and cleanup of nuclear weapons facilities.

trophic status: Classification of a lake or water body as eutrophic,

oligotrophic, mesotrophic, or hypertrophic.

troposphere: The layer of the atmosphere closest to the earth’s

surface. (EPA, December 1997)

U

ultraviolet (UV) radiation Radiation from the sun that can be

useful or potentially harmful. UV radiation from one part of the

spectrum (UV-A) enhance plant life. UV radiation from other parts of

the spectrum (UV-B) can cause skin cancer or other tissue damage.

The ozone layer in the atmosphere partly shields earth from UV

radiation reaching the surface. (EPA, December 1997)

underground storage tanks: Tanks and their underground piping

that have at least 10 percent of their combined volume underground.

urban and built-up areas: A National Resources Inventory land

cover/use category consisting of residential, industrial, commercial,

and institutional land construction sites; public administrative sites;

railroad yards; cemeteries; airports; golf courses; sanitary structures

and spillways; small parks (less than 10 acres) within urban and

built-up areas; and highways, railroads, and other transportation

facilities if they are surrounded by urban areas. Also included are

tracts of less than 10 acres that do not meet the above definition

but are completely surrounded by urban and built-up land. (USDA,

NRCS, 2000)

urbanized areas (UAs) and urban clusters (UCs): Densely settled

areas consisting of core census block groups that have a population

density of at least 1,000 people per square mile and other

surrounding census blocks that have an overall density of at least

500 people per square mile. UAs contain 50,000 or more people;

UCs contain at least 2,500 people but fewer than 50,000. (U.S.

Census Bureau, 2001)

urban and suburban areas: Places where the land is primarily

devoted to buildings, houses, roads, concrete, grassy lawns, and

other elements of human use and construction. Urban and suburban

areas, in which about three-fourths of all Americans live, span a

range of density, from the city center–characterized by high-rise

buildings and little green space–to the suburban fringe–where

development thins to a rural landscape. This definition does not

include all developed lands, for example, small residential zones, the

area of rural interstate highways, farmsteads, and the like, which are

“developed but are not sufficiently built up to be considered “urban

or suburban.” (The Heinz Center, 2002)

urbanization: The concentration of development in relatively small

areas (cities and suburbs). The U.S. Census Bureau defines “urban”

as areas with densities of people above 1.5 people per acre.
D-16 Glossary of Terms Appendix D

V-Z

vehicle miles traveled: A measure of the extent of motor vehicle

operation; the total number of vehicle miles traveled by all vehicles

within a specific geographic area over a given period of time. Vehicle

miles traveled and other variables are used to estimate air pollutant

emissions. 

vernal pools: Seasonal wetlands that occur under the

Mediterranean climate conditions of the West Coast. They are

covered by shallow water for variable periods from winter to spring

but may be completely dry for most of the summer and fall. These

wetlands range in size from small puddles to shallow lakes and are

usually found in a gently sloping plain of grassland. Beneath vernal

pools lies either bedrock or a hard clay layer in the soil that helps

keep water in the pool.

volatile organic compounds: Chemicals, such as gasoline and

perchloroethylene (a dry cleaning solvent) that contain carbon and

vaporize readily. 

waste minimization priority chemicals: A group of 30

chemicals—3 metals (lead, mercury, and cadmium) and 27 organic

compounds—identified as the highest priority for reduction in

industrial and hazardous waste.

water clarity: A measure of how clear a body of water is; measured

in the distance light penetrates into the water.

water quality criteria: Levels of water quality expected to render a

body of water suitable for its designated use. Criteria are based on

specific levels of pollutants that would make the water harmful if

used for drinking, swimming, irrigation, fish production, or industrial

processes. (EPA, December 1997)

water quality standards: State-adopted and EPA-approved ambient

standards for water bodies. The standards define the water quality

goals of a water body by designating the uses of the water and

setting criteria to protect those uses. The standards protect public

health and welfare, enhance the quality of the water, and provide the

baseline for surface water protection under the Clean Water Act.

waterborne disease outbreak: is defined as an event in which (1)

more than two persons have experienced an illness after either the

ingestion of drinking water or exposure to water encountered in

recreational or occupational settings, and (2) epidemiologic

evidence implicates water as the probable source of illness.

watershed: An area of land from which all water that drains from it

flows to a single water body.

wetland ecosystems: Areas that are inundated or saturated by

surface or ground water at a frequency and duration sufficient to

support, and that under normal circumstances do support, a

prevalence of vegetation typically adapted for life in saturated soil

conditions. Wetlands generally include swamps, marshes, bogs and

similar areas.

EPA’s Draft Report on the Environment 2003 Q Technical Document
Appendix E: 

References
E-2 References Appendix E

Chapter 1: 

Cleaner Air

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U.S. Environmental Protection Agency, Office of Groundwater

Drinking Water. Groundwater and drinking water: drinking water

glossary. November 26, 2002. (December 3, 2002;

http://www.epa.gov/safewater/glossary.htm).
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix E References E-27

U.S. Environmental Protection Agency. Radiation information:

radiation terms. December 3, 2002. (December 3, 2002;

http://www.epa.gov/radiation/terms/index.html).

U.S. Environmental Protection Agency. Toxic Release Inventory (TRI)

Program. What is TRI? December 9, 2002. (December 9, 2002;

http://www.epa.gov/tri/).

U.S. Environmental Protection Agency, Office of Pollution Prevention

and Toxics. PCBs Home Page. February 3, 2003. (March 7, 2003;

http://www.epa.gov/opptintr/pcb/). 

U.S. Environmental Protection Agency. Mid-Atlantic Integrated

Assessment: habitat loss. 2003. (August 13, 2002;

http://www.epa.gov/maia/html/habitat.html). 

U. S. Food and Drug Administration, Center for Food Safety and

Applied Nutrition, Office of Seafood. National Shellfish Sanitation

Program Model Ordinance, 1999 revision. November 3, 2000.

(August 13, 2002; http://vm.cfsan.fda.gov/~ear/nssporpd.html).

U.S. Geological Survey. Estimated use of water in the United States

in 1990, glossary of water - use terminology. April 10, 1996.

(November 25, 2002; http://water.usgs.gov/watuse/wuglossary.html). 

Appendix F: 

Background and

Chronology
EPA’s Draft Report on the Environment 2003 Q Technical Document

F-2 Background and Chronology Appendix F

On November 13, 2001, Administrator Christine Todd Whitman

directed the U.S. Environmental Protection Agency (EPA) to

undertake an Environmental Indicators Initiative (EII), bringing

together national, regional, and program office indicator efforts to

produce a Draft Report on the Environment (ROE)and a Draft

Report on the Environment Technical Document (ROE TD). This

report is the first step in a multi-year process to identify indicators

indicators to measure progress toward environmental and human

health goals, to identify data gaps and discuss challenges in filling

those gaps, and to ensure the Agency’s accountability to the public.

The ROE TD contains the scientific and technical information from

which the ROE was developed. 

Report Leadership/Partnerships

Administrator Whitman’s chief of staff assembled and chaired a

steering committee, comprising senior career officials from EPA

program, support, and regional offices, to guide the report

development. The Offices of Environmental Information (OEI) and

Research and Development (ORD) were charged with leading an

integrated process to produce the ROE and the ROE TD. Key staff

representatives acted as “theme” or chapter leads, serving as liaisons

with subject matter experts throughout EPA. Other federal agencies

and tribal and state governments also assisted in reviewing the

report and draft development. 

Report Foundation–The Questions 

The process began with a concerted effort across EPA to identify

significant environmental questions both of interest to the public

and fundamental to EPA’s mission to protect the environment and

human health. A series of six workshops was held in early 2002

across EPA program and regional offices for six themes: human

health, ecological condition, air, water, land, and global issues. The

workshops identified key questions and proposed indicators (both

those supported by existing data and potential future indicators),

and noted challenges to implementation and limitations of the

indicators.

The questions focused on “outcomes” – actual environmental results

such as the quality of outdoor air – rather than on more processoriented “outputs” such as numbers of permits written. The

questions included in this report represent a first set that can be

refined and expanded. For some questions, one to several indicators

were identified; for other questions, there were no indicators

available or recommended. 

Indicator Selection

By May 2002, the process had identified key questions and

associated indicators to address them. The questions were organized

into five report chapters: Cleaner Air, Purer Water, Better Protected

Land, Human Health, and Ecological Condition. Indicators to

respond to the questions were recommended from across EPA,

states, tribes, and other federal agencies. The indicators and their

supporting data sets were documented in accordance with a

standard format, which is allowed for technical review of data quality,

sampling design, coverage, data analysis, and data accessibility. 

An example of the quality review form is presented in Appendix G.

For the national indicators that were identified, there was a wide

variation in the availability of data, as the lack of data was a major

challenge and limitation in writing the chapters.

An expert review was held to review and assess the potential

indicators. External EPA experts were invited to participate in a twoday workshop in mid-June 2002 in the Washington, D.C. area, to

discuss and record their assessments of the indicators. The reviewers

were asked to evaluate the quality review forms for the proposed

indicators in advance of the workshop and then to discuss their

assessments in small groups of other reviewers at the workshop (an

expert review evaluation form is presented in Appendix H).

Guidance was given to the expert reviewers asking that they review

the proposed indicators to evaluate:

Q Quality of the data set supporting the indicator;

Q Scientific basis for the use of the indicator as a measure of the

quality of the environment;

Q Utility of the indicator in measuring the quality of the

environment; and 

Q Limitations in using the indicator to measure the quality of the

environment.
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix F Background and Chronology F-3

Draft Report Development and Review

After determining a set of indicators, EPA developed and refined

several drafts of the report. In November 2002, EPA shared a draft

with federal and state agencies and the Environmental Council of

States (ECOS) and took their comments into consideration in

developing the content of the ROE technical document. That draft

was the basis for final review and comment by the Council on

Environmental Quality (CEQ) and the Office of Management and

Budget (OMB). 

This current draft report is now available to the public.

Chronology of Significant Events for Document

Development

A chronology of significant milestones in the development of the

draft Report on the Environment Technical Document is presented

below.

November 2001 Administrator’s Memo Launching the 

Environmental Indicators Initiative

January-February 2002 Theme Workshop Meetings – Initial 

Identification of Questions and 

Potential Indicators 

March-April 2002 Development of Report Outlines

April 2002 ECOS-Sponsored Meeting with 

Interested States 

May 2002 Quality Review Process 

June 2002 External Expert Review Workshop

July 2002-May 2003 Drafting of ROE and ROE Technical 

Document

Nov. 2002-May 2003 State/Federal Interagency/OMB/CEQ 

Review Meetings

June 2003 Release of Draft ROE and ROE 

Technical Document

Appendix G:

Indicator Quality

Review Form 
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-2 Indicator Quality Review Form Appendix G

A. General Background

1. What is the theme this indicator is part of (e.g., land, water, air, global change, human health, ecological health)?

2. What is the name of the Indicator/data set?

3. What is the question the indicator set is being proposed to address?

4. How does this indicator address the questions? (conceptual relevance)

5. Does this indicator/data set require additional processing to optimally address this question and if so, what? 

6. Has this indicator previously been peer reviewed? If so, please provide details. This question has been moved from Data Processing 

and Analysis section.
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix G Indicator Quality Review Form G-3

B. Data Quality

1. What is the known quality of the entire data set?

2. Has any standard data documentation, such as FGDC metadata, been developed to support these data? 

(If yes, please provide reference or source.)

3. Why were the data originally collected (e.g., what is being measured or monitored)? 

4. Were data collected under a single program or were data from multiple programs combined? If multiple data sets were combined 

please address the quality for each data set independently.

5. What was (were) the program or programs under which the data were collected?

6. Did these programs have quality assurance plans to verify, corroborate, ground truth or otherwise assess the accuracy of the data?
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-4 Indicator Quality Review Form Appendix G

7. If yes, are the quality assurance program plans available (and where)?

8. Were the quality assurance plans followed?

9. Were the analytical methods used consistent throughout the data set? 

10. If not what effects could the different analytical methods have on the indicator results?

11. Are you aware of any sources of error that may affect the findings developed from these data? Error types could include errors of 

omission, commission, mis-classification, incorrect georeferencing, mis-documentation or mistakes in the processing of data. 

This question is revised from “What are some of the uncertainties of the data and on the findings.” 
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix G Indicator Quality Review Form G-5

C. Sample Design

1. Generally describe how the data are/were collected (Research, general monitoring, compliance monitoring, regulatory requirement)? 

If collected under a regulatory requirement, please specify the regulation and links to the regulation and associated guidance.

2. What was the sample design or the monitoring plan?

3. Were any specific strata omitted from the sampling plan (e.g., small systems not in the sampling plan, roads less than 2 miles long, 

habitat types less than 20 acres)?

4. Which of the processes below was used to select the sites where information is/was collected? 

a) Sites selected using a statistical design that enables generalization to entire resource (e.g., probability survey design to select sample of 

lakes or streams for the United States. such as NRI, NASS, FHM, FIA)

b) Sites determined to meet administrative or regulatory requirements such as sources of or water supply systems.

c) Sites chosen to address suspected or known problems (e.g., Hot spots).

d) Randomly selected sites.

e) Sites selected in unknown way.
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-6 Indicator Quality Review Form Appendix G

5. When did the monitoring begin?

6. When did the monitoring end?

7. What was the periodicity of the sample (yearly, seasonally, quarterly, monthly, weekly, daily, etc.)?

8. Were there any major gaps in the data either spatially or temporally (please explain)
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix G Indicator Quality Review Form G-7

D. Coverage 

1. Is there uniform national coverage of information for this indicator? 

2. Were data collected in some areas but not others?

3. Was the data collected using remote sensing? If yes please specify the sensor, date and the resolution of the data.

4. If the data are derived from mapped information, what was the original map scale or resolution? 
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-8 Indicator Quality Review Form Appendix G

E. Data Processing and Analyses

1. What kinds of analyses have been performed on the data? Please explain.

2. Are the values used in the indicator raw data? Aggregated data? Calculated data? Inferred data? Last sentence deleted, 

redundant with 1.

3. Are these analyses standard methods? Please reference.

4. Were these results published? If yes please give reference or link.

5. Were these results peer reviewed? If yes by whom? Give references.

6. How were the values calculated or determined?
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix G Indicator Quality Review Form G-9

7 .Please describe the basis of the classification scheme? Why was this scheme chosen? 

8. How are the values interpreted? 

9. Are there established ranges that indicate the state of the environment? If yes how were these values established? Are the values 

consistent across the spatial extent of the data set?

10. Is the Indicator developed based on a model? If so, what is this model?

11. Has the model been published?

12. Has the model been peer reviewed?

13. How are data gaps handled when the model is applied?

14. What is the scientific inference process used to generalize from site-specific information to the national coverage?
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-10 Indicator Quality Review Form Appendix G

15. Which of the following was used to generalize or portray data beyond the specific sampling points?

a) Defensible statistical survey analysis inference procedures used to generalize to entire United States. (e.g., current OW National Lake 

Fish tissue contaminant survey, FIA, FHM, NRI)

b) Defensible statistical model inference procedures used to generalize to entire United States (e.g., generation of wet deposition maps 

for US or generation of air quality information using kriging).

c) Semi-empirical environmental/ecological model predictions. (e.g., USGS use of SPARROW model to predict nutrients in rivers based on 

statistical relationships and simple hydrologic flow models)

d) Generalization is restricted to sites visited and it is possible to give a well- defined, meaningful definition of the portion of the ecological 

resource covered.

e) No generalization possible and no meaningful way to identify the subset of the ecological resource represented by the collection of sites.
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix G Indicator Quality Review Form G-11

F. Data Accessibility

1. Are the data readily available? If yes, please give reference, link or contact.

2. Are the summary reports available? If yes, please give reference, link or contact.

3. Have these results been published? If yes, please give reference.
EPA’s Draft Report on the Environment 2003 Q Technical Document

G-12 Indicator Quality Review Form Appendix G

G. Message or Interpretation

1. Are the messages or answers to the questions appropriate, sound, and understandable?

EMAP Indicator Development Strategy (EPA/620/R-94/022) 

Evaluation Guidelines for Ecological Indicators (EPA/620/R-99/005).

EMAP Assessment Framework
Appendix H:

EPA Draft Report

on the 

Environment 

Expert Review

Workshop

Evaluation Form
H-2 Workshop Evaluation Form Appendix H

EPA Draft Report on the Environment Expert Review

Workshop Evaluation Form

Name of Theme:

Name of Indicator:

Associated Question:

Reviewer Name:

Please provide brief answers of one to three paragraphs for each question in the following sections. Under the “Primary Questions” section,

please provide a summary evaluation of the indicator’s data quality and coverage, suitability, and fit. Evaluations shall be based on a scale from

1 to 5 (Excellent = 5; Adequate = 3; Poor = 1). 

Primary Questions

Data Quality and Coverage

1. Do the indicator and the supporting data provide adequate geographic coverage for national reporting?

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix H Workshop Evaluation Form H-3

2. What is the quality of the data set supporting the indicator? What is known about the quality? (In your response, please address the adequacy of the data to support the indicator; whether there is uniform national coverage, quality assurance/quality control issues, documentation, consistent analytical methods, and sample design issues.)

*Summary Evaluation of Data Quality and Coverage (Excellent = 5; Adequate = 3; Poor = 1):

Suitability of Indicator

3. Is there a credible scientific basis for this indicator? 
H-4 Workshop Evaluation Form Appendix H

4. What are the limitations of this indicator? (e.g., guidance relevant to using the data supporting the indicator, including challenges and

gaps)

*Summary Evaluation of Suitability of Indicator (Excellent = 5; Adequate = 3; Poor = 1):

Question and Indicator Fit

5. How well does the indicator answer or fit the associated questions? 

*Summary Evaluation of Question and Indicator Fit (Excellent=5; Adequate=3; Poor=1):

EPA’s Draft Report on the Environment 2003 Q Technical Document
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix H Workshop Evaluation Form H-5

Recommendations

6. Considering your overall evaluation, how can the indicator be improved? (e.g., more precise language, alternative data source, different

scale) 

Secondary Questions

Please address questions # 7 and # 8 primarily in the context of helping to improve indicator use and development in future years.

Other Considerations

7. Are there additional or alternative indicators that would help address the question?
EPA’s Draft Report on the Environment 2003 Q Technical Document

H-6 Workshop Evaluation Form Appendix H

8. Are there other questions and associated indicators that better address the issue? (Please use draft document outline as the basis for

developing a short answer.)
Appendix I: 

Summary Tables 

of Questions 

and

Indicators
EPA’s Draft Report on the Environment 2003 Q Technical Document

I-2 Summary Tables of Questions and Indicators Appendix I

-

-

-

-

-

-

-

Question Indicator Name Category Section

Question Indicator Name Category Section

Deposition: wet sulfate and wet nitrogen

Emissions (utility): sulfur dioxide and nitrogen oxides 

2

2

What ecological effects are associated with 

acid deposition? 

What are the deposition rates of pollutants that cause 

acid rain? 

What are the emissions of pollutants that form acid rain?

Acid Deposition

What is the quality of outdoor air in the United States? 

(See also following four questions)

Number and percentage of days that metropolitan 

statistical areas (MSAs) have Air Quality Index (AQI) values 

greater than 100

2

Number of people living in areas with air quality levels 

above the NAAQS for particulate matter (PM) and ozone

1

Ambient concentrations of particulate matter: PM2.5 and 1 1.1.1.b

PM10

Ambient concentrations of ozone: 8-hour and 1-hour 1 1.1.1.b

Ambient concentrations of lead 1 1.1.1.b

What are the impacts of air pollution on visibility in 

national parks and other protected lands? Visibility 1

What are the concentrations of toxic air pollutants in

ambient air? 

Ambient concentrations of selected air toxics 2

What contributes to outdoor air pollution?

(See also following three questions)

See emissions indicators

Emissions: particulate matter (PM2.5 and PM10) 2 1.1.2.a 

sulfur dioxide, nitrogen oxides, and 

volatile organic compounds

Lead emissions 2 1.1.2.a

What are contributors to toxic air pollutants in 

ambient air?

Air toxics emissions

To what extent is U.S. air quality the result of pollution

from other countries, and to what extent does U.S. air 

pollution affect other countries? 

No Category 1 or 2 indicators identified 

What human health effects are associated with 

outdoor air pollution? 

No Category 1 or 2 indicators identified

Also see Human Health chapter

What ecological effects are associated with outdoor 

air pollution?

No Category 1 or 2 indicators identified 

Also see Ecological Condition chapter

How many people are living in areas with particulate matter 

and ozone levels above the National Ambient Air Quality 

Standards (NAAQS)? 

What are the concentrations of some criteria air 

pollutants: PM2.5, PM10, ozone, and lead? 

What are contributors to particulate matter, 

ozone, and lead in ambient air?

Outdoor Air Quality

Chapter 1: Cleaner Air – Questions and Indicators

1.1.1.a

1.1.1.c

1.1.1.d

1.1.2

2 1.1.2.b

1.1.2.c

1.1.3

1.1.4

1.2.1

1.2.2

No Category 1 or 2 indicators identified 1.2.3

Also see Ecological Condition chapter

1.1.1
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix I Summary Tables of Questions and Indicators I-3

Question Indicator Name Category

U.S. homes above EPA's radon action levels 2

Percentage of homes where young children are 

exposed to environmental tobacco smoke 2

Section

What contributes to indoor air pollution? No Category 1 or 2 indicators identified 

Also see Human Health chapter 

No Category 1 or 2 indicators identified

Also see Human Health chapter 

What human health effects are associated with 

indoor air pollution? 

Question Indicator Name Category

What are the trends in the Earth's ozone layer? Ozone levels over North America 1

Worldwide and U.S. production of ozone-depleting 

substances (ODSs) 2

Concentrations of ozone-depleting substances (effective 

equivalent chlorine) 2

Section

What human health effects are associated 

with stratospheric ozone depletion? No Category 1 or 2 indicators identified 

What ecological effects are associated with stratospheric 

ozone depletion? 

No Category 1 or 2 indicators identified 

What is the quality of the air in buildings in the United States? 

What is causing changes to the ozone layer? 

Chapter 1: Cleaner Air – Questions and Indicators (continued)

Indoor Air Quality

Stratospheric Ozone

1.3.1

1.3.2

1.4.1

1.4.2

1.4.2

1.4.3

1.4.4

1.3.1

1.3.3
EPA’s Draft Report on the Environment 2003 Q Technical Document

I-4 Summary Tables of Questions and Indicators Appendix I

Question Indicator Name Category

Altered fresh water ecosystems 2

Lake Trophic State Index 2

Wetland extent and change 1

Sources of wetland change/loss 2

Water clarity in coastal waters 2

Dissolved oxygen in coastal waters 2

Total organic carbon in sediments 2

Chlorophyll concentrations 2

Percent urban land cover in riparian areas 2

Agricultural lands in riparian areas 2

Population density in coastal areas 2

Changing stream flows 1

2

Sedimentation index 2

Atmospheric deposition of nitrogen 2

2

Total nitrogen in coastal waters 2

Phosphorus in farmland, forested, and urban streams 2

Phosphorus in large rivers 2

Total phosphorus in coastal waters 2

Atmospheric deposition of mercury 2

Chemical contamination in streams and ground water 2

Pesticides in farmland streams and ground water 2

Acid sensitivity in lakes and streams 2

Sediment contamination of inland waters 2

Sediment contamination of coastal waters 2

Sediment toxicity in estuaries 2

What ecological effects are associated 

with impaired waters?

Fish Index of Biotic Integrity in streams

 Also see Ecological Condition chapter

What is the condition of coastal waters?

What is the condition of fresh surface waters and 

watersheds in the U.S.?

What are the extent and condition of wetlands?

What are pressures to water quality?

Chapter 2: Purer Water - Questions and Indicators

Waters and Watersheds

Section

Nitrate in farmland, forested, and urban streams and

Number/duration of dry stream flow periods in

 grassland/shrublands

ground water

Toxic releases to water of mercury, dioxin, lead, PCBs,

 and PBTs

2.2.1

2.2.1

2.2.2

2.2.2

2.2.3

2.2.3

2.2.3

2.2.3

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.a

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.b

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2.2.4.c

2

2 2.2.5

Macroinvertebrate Biotic Integrity index for streams

 Also see Ecological Condition chapter

2 2.2.5

Benthic Community Index for coastal waters

 Also see Ecological Condition chapter

2 2.2.5

General pressures

Nutrient pressures

Chemical Pressures
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix I Summary Tables of Questions and Indicators I-5

Question Indicator Name Category

What is the quality of drinking water? Population served by community water systems 

that meets all health-based standards 1

What are sources of drinking water contamination? No Category 1 or 2 indicators identified

What human health effects are associated with drinking 

 contaminated water?

No Category 1 or 2 indicators identified 

Also see Human Health chapter

Question Indicator Name Category

What is the condition of waters supporting 

recreational use? Number of beach days that beaches are closed or 

under advisory

2

What are sources of recreational water pollution? No Category 1 or 2 indicators identified

What human health effects are associated with recreation in 

contaminated waters?

No Category 1 or 2 indicators identified 

Also see Human Health chapter

Question Indicator Name Category

Contaminants in fresh water fish 2

Percent of river miles and lake acres under fish 

consumption advisories

2

Number of watersheds exceeding health-based 

national water quality criteria for mercury and PCBs 

in fish tissue

2

What are contaminants in fish and shellfish, and where 

do they originate? 

What human health effects are associated with consuming 

contaminated fish and shellfish?

No Category 1 or 2 indicators identified

Also see Human Health chapter

What is the condition of waters that support consumption 

of fish and shellfish?

Chapter 2: Purer Water - Questions and Indicators (continued)

Drinking Water

Recreation in and on the Water

Consumption of Fish and Shellfish 

Section

Section

Section

No Category 1 or 2 indicators identified

2.3.1

2.4.1

2.5.1

2.5.1

2.5.1

2.5.2

2.5.3

2.4.2

2.4.3

2.3.2

2.3.3
EPA’s Draft Report on the Environment 2003 Q Technical Document

I-6 Summary Tables of Questions and Indicators Appendix I

Question Indicator Name Category Section

Question Indicator Name Category Section

Chemicals in the Landscape

1

2

1

2

2

1

2

3.1.1

3.1.1

3.1.2

3.1.2

3.1.3

3.1.4 

3.1.5

3.1.6

Land Use

Chapter 3: Better Protected Land – Questions and Indicators

How much and what types of toxic substances are released 

into the environment?

Agricultural pesticide use

Fertilizer use

Pesticide residues in food

Potential pesticide runoff from farm fields

Risk of nitrogen export

Risk of phosphorus export

No Category 1 or 2 indicator identified

No Category 1 or 2 indicator identified

2

2

2

1

1

2

2

3.2.1

3.2.2

3.2.3

3.2.4

3.2.4

3.2.4

3.2.4

3.2.5

3.2.6

What human health effects are associated with pesticides, 

fertilizers, and toxic substances?

What ecological effects are associated with pesticides, 

fertilizers, and toxic substances?

What is the extent of developed lands?

What is the extent of farmlands?

What is the extent of grasslands and shrublands?

What is the extent of forest lands?

What human health effects are associated with land use?

What ecological effects are associated with land use? 

What is the volume, distribution, and extent of pesticide use?

What is the volume, distribution, and extent of fertilizer use?

What is the potential disposition of chemicals from land?

Quantity and type of toxic chemicals released 

and managed

Extent of developed lands 

Extent of urban and suburban lands 

Extent of agricultural land uses 

The farmland landscape 

Extent of grasslands and shrublands

Extent of forest area, ownership, and management 

No Category 1 or 2 indicator identified 

Sediment runoff potential from croplands and pasturelands
Technical Document Q EPA’s Draft Report on the Environment 2003

Appendix I Summary Tables of Questions and Indicators I-7

Question Indicator Name Category Section

2

2

2

2

2

2

2

3.3.1

3.3.1

3.3.1

3.3.2

3.3.2

3.3.3

3.3.3

3.3.4

3.3.5

Chapter 3: Better Protected Land – Questions and Indicators (continued)

Waste and Contaminated Lands

Quantity of municipal solid waste (MSW) generated and managed

Quantity of RCRA hazardous waste generated and managed

Quantity of radioactive waste generated and in inventory 

Number and location of municipal solid waste (MSW) landfills

Number and location of RCRA hazardous waste management facilities 

Number and location of Superfund National Priorities List (NPL) sites

Number and location of RCRA Corrective Action sites

What human health effects are associated with waste 

management and contaminated lands?

What ecological effects are associated with waste 

management and contaminated lands? 

What is the extent of land used for waste management?

What is the extent of contaminated lands?

How much and what types of waste are generated and

managed ? 

No Category 1 or 2 indicator identified 

No Category 1 or 2 indicator identified 
EPA’s Draft Report on the Environment 2003 Q Technical Document

Appendix I Summary Tables of Questions and Indicators I-8

Question Indicator Name Category Section

Measuring Exposure to Environmental Pollution: Indicators and Trends

 Blood lead level 1 4.4.3

 Urine arsenic level 2 4.4.3

 Blood mercury level 1 4.4.3

 Blood cadmium level 1 4.4.3

 Blood cotinine level 1 4.4.4

 Blood volatile organic compound levels 1 4.4.5

 Urine organophosphate levels to indicate pesticides 1 4.4.6

 No Category 1 or 2 indicators identified 4.4.7

 Blood lead level in children 1 4.4.8

 Blood mercury level in children 1 4.4.8

 Blood cotinine level in children 1 4.4.8

 No Category 1 or 2 indicators identified 4.4.9

 No Category 1 or 2 indicators identified

Also see Cleaner Air chapter 4.4.9

 No Category 1 or 2 indicators identified 4.4.9

 No Category 1 or 2 indicators identified 4.4.9

Chapter 4: Human Health - Questions and Indicators

Health Status of the U.S. : Indicators and Trends of Health and Disease

Question Indicator Name Category Section

 Life expectancy 1 4.3.1

 Cancer mortality 1 4.3.2

 Cancer incidence 2 4.3.2

 Cardiovascular disease mortality 1 4.3.2

 Cardiovascular disease prevalence 1 4.3.2

 Chronic obstructive pulmonary disease mortality 1 4.3.2

 Asthma mortality 1 4.3.2

 Asthma prevalence 1 4.3.2

 Cholera prevalence 2 4.3.3

 Cryptosporidiosis prevalence 2 4.3.3

E. coli O157:H7 prevalence 2 4.3.3

 Hepatitis A prevalence 2 4.3.3

 Salmonellosis prevalence 2 4.3.3

 Shigellosis prevalence 2 4.3.3

 Typhoid fever prevalence 2 4.3.3

 Infant mortality 1 4.3.4

 Low birthweight incidence 1 4.3.4

 Childhood cancer mortality 1 4.3.4

 Childhood cancer incidence 2 4.3.4

 Childhood asthma mortality 1 4.3.4

 Childhood asthma prevalence 1 4.3.4

 Deaths due to birth defects 1 4.3.4

 Birth defect incidence 1 4.3.4

What is the level of exposure to cotinine? 

What is the level of exposure to volatile organic compounds? 

What is the level of exposure to pesticides? 

What is the level of exposure to persistent 

 organic pollutants? 

Question Indicator Name Category Section

What are the trends for life expectancy? 

What are the trends for cancer, cardiovascular disease, 

 chronic obstructive pulmonary disease and asthma? 

What are the trends for gastrointestinal illness? 

What are the trends for children's environmental health issues? 

What are the trends in exposure to environmental 

 pollutants for children?

What is the level of exposure to radiation? 

What is the level of exposure to air pollutants?

What is the level of exposure to biological pollutants? 

What is the level of exposure to disinfection by-products? 

What is the level of exposure to heavy metals?
Technical Document Q EPA’s Draft Report on the Environment 2003

I-9 Summary Tables of Questions and Indicators Appendix I

Question Indicator Name Category Section

Question Indicator Name Category Section

Question Indicator Name Category Section

Chapter 5: Ecological Condition - Questions and Indicators

Forests

Extent of forest area, ownership, and management 1 3.1.4

Nitrate in farmland, forested, and urban streams and ground water 2 2.2.4.b

Deposition: wet sulfate and wet nitrogen 2 1.2.2

Changing stream flows 1 2.2.4.a

Extent of area by forest type 1 5.2

Forest age class 2 5.2

Forest pattern and fragmentation 2 5.2

At-risk native forest species 2 5.2

Populations of representative forest species 2 5.2

Forest disturbance: fire, insects, and disease 1 5.2

Tree condition 2 5.2

Ozone injury to trees 2 5.2

Carbon storage 2 5.2

Soil compaction 2 5.2

Soil erosion 2 5.2

Processes beyond the range of historic variation 2 5.2

Extent of agricultural land uses 1 3.1.2

The farmland landscape 1 3.1.2

Nitrate in farmland, forested, and urban streams and ground water 2 2.2.4.b

Phosphorus in farmland, forested and urban streams 2 2.2.4.b

Pesticides in farmland streams and ground water 2 2.2.4.c

Potential pesticide runoff from farm fields 2 3.2.4

Sediment runoff potential from croplands and pasturelands 2 3.1.6

Pesticide leaching potential 2 5.3

Soil quality index 2 5.3

Soil erosion 2 5.3

What is the ecological condition of forests?

What is the ecological condition of farmlands?

Farmlands

Extent of grasslands and shrublands 1 3.1.3

Number/duration of dry stream flow periods in grasslands and shrublands 2 2.2.4.a

At-risk native grassland and shrubland species 2 5.4

Population trends of invasive and native non-invasive bird species 1 5.4

Grasslands and Shrublands

What is the ecological condition of grasslands 

and shrublands?

Note: Italicized indicators are presented in other chapters.
EPA’s Draft Report on the Environment 2003 Q Technical Document

Appendix I Summary Tables of Questions and Indicators I-10

What is the ecological condition of coasts 

and oceans?

Question Indicator Name Category Section

Question Indicator Name Category Section

Question Indicator Name Category Section

Extent of urban and suburban lands 1 3.1.1

Ambient concentrations of ozone: 8-hour and 1-hour 2 1.1.1.b

Nitrate in farmland, forested and urban streams, and ground water 2 2.2.4.b

Phosphorus in farmland, forested, and urban streams 2 2.2.4.b

Chemical contamination in urban streams and ground water 2 2.2.4.c

Patches of forest, grassland, shrubland, and wetland in urban/suburban areas 2 5.5

Wetland extent and change 1 2.2.2

Altered fresh water ecosystems 2 2.2.1

Contaminants in fresh water fish 2 2.5.1

Phosphorus in large rivers 2 2.2.4.b

Lake Trophic State Index 2 2.2.1

Chemical contamination in streams and ground water 2 2.2.4.c

Acid sensitivity in lakes and streams 2 2.2.4.c

Changing stream flows 1 2.2.4.a

Sedimentation index 2 2.2.4.a

Extent of ponds, lakes, and reservoirs 1 5.6

At-risk native fresh water species 2 5.6

Non-native fresh water species 2 5.6

Animal deaths and deformities 2 5.6

At-risk fresh water plant communities 2 5.6

Fish Index of Biotic Integrity in streams 2 5.6

Macroinvertebrate Biotic Integrity Index for streams 2 5.6

Chapter 5: Ecological Condition - Questions and Indicators (continued)

Urban and Suburban Lands

What is the ecological condition of urban 

and suburban areas?

Fresh Waters

What is the ecological condition of fresh waters?

Chlorophyll concentrations 2 2.2.3

Water clarity in coastal waters 2 2.2.3

Total nitrogen in coastal waters 2 2.2.4.b

Total phosphorus in coastal waters 2 2.2.4.b

Dissolved oxygen in coastal waters 2 2.2.3

Total organic carbon in sediments 2 2.2.3

Sediment contamination of coastal waters 2 2.2.4.c

Sediment toxicity in estuaries 2 2.2.4.c

Extent of estuaries and coastline 1 5.7

Coastal living habitats 2 5.7

Shoreline types 2 5.7

Benthic Community Index 2 5.7

Fish diversity 2 5.7

Submerged aquatic vegetation 2 5.7

Fish abnormalities 2 5.7

Unusual marine mortalities 2 5.7

Coasts and Oceans

Note: Italicized indicators are presented in other chapters.
Technical Document Q EPA’s Draft Report on the Environment 2003

I-11 Summary Tables of Questions and Indicators Appendix I

Question Indicator Name Category Section

Ecosystem extent 2 5.8

At-risk native species 2 5.8

Bird Community Index 2 5.8

Terrestrial Plant Growth Index 1 5.8

Movement of nitrogen 1 5.8

Chemical contamination 2 5.8

Chapter 5: Ecological Condition - Questions and Indicators (continued)

The Entire Nation

What is the ecological condition of the 

entire nation? 

Note: Italicized indicators are presented in other chapters.