EPA’s Report on the Environment
 

Highlights of 

National Trends 

2008 
We are pleased to present EPA’s 2008 Report on the Environment: Highlights of 

National Trends (ROE Highlights), which provides an important resource for the 

general public for better understanding trends in our nation’s health and environment. This document presents some of the key findings from the more 

comprehensive technical report, EPA’s 2008 Report on the Environment (ROE ) 

in an easy to understand format. 

These reports are the culmination of an effort begun over five years ago to 

establish a set of scientifically sound measures, or indicators, that help answer 

questions of vital importance to EPA’s mission. Using these indicators, the 

reports present what we know—and don’t know—about the condition of air, 

water, land, human health, and ecological condition in the United States. The 

reports show both positive and negative trends. 

We have made numerous improvements to the indicators as well as to the 

indicator selection and reporting process. This included the extraordinary step 

of having the ROE Highlights reviewed in a public forum to determine if citizens—in addition to scientists—found the proposed indicators useful. Through 

this open and transparent process, we have also created opportunities to 

establish and strengthen our partnerships among federal, state, and nongovernmental organizations for data sharing and data needs planning to support indicator development and improvement. 

These documents are not report cards on EPA’s programs, nor do they interpret the data or draw conclusions about the information presented. Instead, 

the reports present the best available, scientifically sound information on 

national-level environmental and health trends that are of interest to EPA and 

the public and that may help to inform EPA’s strategic planning. 

We invite you to visit www.epa.gov/roe. There you will find the underlying 

data, metadata, references and peer review documentation for the ROE indicators as well as the full versions of the two reports. This website will be 

updated periodically so the information remains current and relevant. 

We welcome and encourage your involvement in this ongoing effort. You can 

provide feedback to us at www.epa.gov/roe. 

MOLLY O’NEILL GEORGE M. GRAY, PH.D. 

Assistant Administrator for Environmental Assistant Administrator for Research 

Information and Chief Information Officer and Development 
COVER

EPA’S 2008 REPORT ON THE ENVIRONMENT:
 

HIGHLIGHTS OF NATIONAL TRENDS
 

The U.S. Environmental Protection 

Agency (EPA) developed EPA’s 

2008 Report on the Environment 

to help answer questions that are 

of critical importance to the 

Agency’s mission to protect human 

health and the environment. The 

Report on the Environment documents trends in the condition of 

the nation’s environment and 

human health and identifies significant gaps in our knowledge. It is 

not intended to be a report card 

on EPA’s programs and activities. 

CONTENTS 

About This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
 

Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
 

Outdoor Air . . . . . . . . . . . . . . . . . . . . . . . .5
 

Acid Rain and Regional Haze . . . . . . . . . . .6
 

Ozone Depletion . . . . . . . . . . . . . . . . . . . .7
 

Greenhouse Gases . . . . . . . . . . . . . . . . . . .8
 

Indoor Air . . . . . . . . . . . . . . . . . . . . . . . . . .9
 

Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
 

Fresh Surface Waters . . . . . . . . . . . . . . . .11
 

Ground Water . . . . . . . . . . . . . . . . . . . . .12
 

Wetlands . . . . . . . . . . . . . . . . . . . . . . . . .13
 

Coastal Waters . . . . . . . . . . . . . . . . . . . . .14
 

Drinking Water . . . . . . . . . . . . . . . . . . . . .15
 

Recreational Waters . . . . . . . . . . . . . . . . .16
 

Consumable Fish and Shellfish . . . . . . . . .17
 

Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
 

Land Cover . . . . . . . . . . . . . . . . . . . . . . . .19
 

Land Use . . . . . . . . . . . . . . . . . . . . . . . . .20
 

Wastes and the Environment . . . . . . . . . .21
 

Chemicals Applied and Released 


to Land . . . . . . . . . . . . . . . . . . . . . . . . . . .22
 

Contaminated Lands . . . . . . . . . . . . . . . .23
 

Human Exposure and Health . . . . . . . . . . . . . . . . . . . . . .24
 

Exposure to Environmental 


Contaminants . . . . . . . . . . . . . . . . . . . . . .25
 

Health Status . . . . . . . . . . . . . . . . . . . . . .26
 

Diseases and Health Conditions . . . . . . . .27
 

Ecological Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
 

Patterns in Ecological Systems . . . . . . . . .29
 

Biological Diversity . . . . . . . . . . . . . . . . . .30
 

Ecological Processes . . . . . . . . . . . . . . . . .31
 

Physical and Chemical Attributes 


of Ecological Systems . . . . . . . . . . . . . . . .32
 

Ecological Exposure to Contaminants . . . . .33
 

Looking Ahead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
 

List of Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
 

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
 
ABOUT THIS DOCUMENT
 

Written for a general audience, this document, EPA’s 2008 Report on the 

Environment: Highlights of National Trends, summarizes some important 

findings from a more comprehensive companion report, EPA’s 2008 Report 

on the Environment. An electronic version of the report, available at 

www.epa.gov/roe, facilitates navigation and searching across both 

documents. 

Highlights of National Trends is organized around five chapters. Three of the 

chapters (Air, Water, and Land) focus on trends in these environmental 

media. The other two chapters address trends in human health and ecological condition more broadly. 

The chapters are divided into 25 topic pages. Each page summarizes what 

we know—and don’t know—about conditions and trends for the topic. 

The information on these topics comes from highly reliable indicators (see 

box below) and is based on the most recent data available from a variety 

of governmental and non-governmental organizations. 

Highlights of National Trends features a subset of indicators from the more 

comprehensive Report on the Environment. The indicators were selected for 

inclusion based on their importance to the public and to scientists, as well as 

their ability to answer a series of key questions about the environment. These 

key questions and 85 associated indicators form the framework of the Report 

on the Environment and are listed at the end of this document. 

In addition, only a few of the most important data gaps and limitations 

from the Report on the Environment are included in Highlights of National 

Trends. Readers are encouraged to consult the more comprehensive report 

for more information. You can also read about some actions that individuals can take to protect the environment and their own health in the electronic version of Highlights of National Trends at www.epa.gov/roe. 

ENVIRONMENTAL INDICATORS 

The indicators used in the Report on the Environment: 

•	 Rely on actual measurements of environmental and human health
 

conditions over time.
 

•	 Meet a set of standards, which include quality, accuracy, relevance,
 

and comparability.
 

•	 Were reviewed by an independent scientific panel to ensure that they 

meet these standards. 

•	 Are national (or in some cases regional) in coverage. They do not
 

describe trends or conditions for a specific locale. 


•	 Come from many governmental and non-governmental organizations, 

which collect data at different time periods and for varying purposes. 

•	 Can only partially answer the key questions. 

About This Document 	 2
 
ABOUT THE DATA IN 

THE REPORT ON THE 

ENVIRONMENT 

UPDATES TO THE 

REPORT ON THE 

ENVIRONMENT 

The indicators in the Report on the Environment are based on actual measurements of the environment over time and do not describe activities to protect 

the environment. 

The length of time and geographic area over which consistent data have been 

gathered varies from one indicator to another. Some indicators cover many 

years, while others address only one point in time (a baseline for measuring 

trends in the future). Most indicators in this report present data at the national 

level, but some regional indicators have been used to illustrate important scenarios and could be applied to the nation in the future. 

All of the indicators were reviewed by an independent panel and meet strict 

definitions and criteria, including scientific quality and national (or in some 

cases regional) coverage. Other sources of information are not included in this 

report because they do not meet one or more of the criteria. While no data 

sources are cited in Highlights of National Trends, sources for all data are available in the larger Report on the Environment document. 

Each topic page in Highlights of National Trends acknowledges some of the 

most important limitations of the indicators presented, or where gaps exist. 

Data limitations are noted to provide the reader with information about the 

quality or extent of the data presented that may affect the way in which they 

are used. Data gaps are noted to identify areas or aspects of the environment 

in which little or no measurement has been conducted. This report does not 

propose actions to reduce data limitations or fill gaps. 

EPA’s 2008 Report on the Environment brings together the most consistent 

and reliable information on national environmental conditions and trends 

currently available under a single cover. It builds on EPA’s Draft Report on the 

Environment 2003, which was the Agency’s first effort to assemble scientifically sound indicators on the status and trends of the nation’s environment. 

Since the release of the 2003 report, EPA has revised, updated, and refined 

the information in the Report on the Environment in response to scientific 

developments as well as stakeholder feedback. EPA will publish periodic 

updates of the Report on the Environment and use it to inform the Agency’s 

strategic planning process. 

EPA’S 2008 REPORT ON THE ENVIRONMENT 

Highlights of National Trends is one of three products that collectively make up 

EPA’s 2008 Report on the Environment. The other two products are: 

•	 EPA’s 2008 Report on the Environment, the source of the information presented in this document. The Report on the Environment is organized around key 

questions about the environment and presents 85 indicators to help answer 

those questions. 

•	 A Web-based tool for navigating and searching EPA’s 2008 Report on the 

Environment and EPA’s 2008 Report on the Environment: Highlights of National 

Trends, available at www.epa.gov/roe. 

About This Document 	 3
 
AIR
 

Outdoor Air 

Acid Rain and Regional Haze 

Ozone Depletion 

Greenhouse Gases 

Indoor Air 

1

Close to the Earth’s surface, air provides the 

oxygen and carbon dioxide needed to sustain human, animal, and plant life. Higher 

up, a natural layer of ozone shields life on Earth 

from the sun’s harmful rays, and at all levels of the 

atmosphere, naturally occurring greenhouse gases 

help maintain a climate suitable for life. Indoors 

and outdoors, from ground level to high above the 

planet’s surface, the condition of the air is critical to 

human health and the environment. 

Tracking the nation’s air quality is challenging 

because of the many sources, types, and effects of 

air pollution. Most outdoor air pollutants can be 

directly traced back to emissions sources that 

release the pollutants into the air. However, some 

air pollutants, such as ozone, are formed in the air 

when an emission reacts with another airborne 

substance. 

Once airborne, pollutants can be transported 

long distances by wind or transformed into other 

compounds. They also can fall back to Earth, contaminating water and land. Both the amount of 

pollutants emitted into the air and how these 

pollutants move through the atmosphere determine air pollution levels, which are measured as 

concentrations. 

Many indicators are needed to characterize outdoor air quality separate from indoor air quality, 

to characterize air quality trends at ground level 

as well as higher in the atmosphere, and to characterize both emissions and concentrations. Also, 

air quality varies considerably with location and 

time, which makes it challenging to obtain a 

representative national picture. 

Chapter 1: Air 4
 
Outdoor air pollutants come 

from human activities such as 

electricity production, industrial 

processes, and transportation, 

and from natural sources like wildfires and wind-blown 

dust. Some of these pollutants can harm human health, 

the environment, and other valued resources. 

Beginning in the 1970s, EPA developed standards to protect human health and the environment from six common air pollutants that pose serious health and 

environmental effects: carbon monoxide, lead, nitrogen 

dioxide, ozone, airborne liquid and solid particles (known 

KEY POINTS 

Nationwide, emissions of criteria pollutants (or the 

pollutants that form them) due to human activities 

have decreased. Between 1990 and 2002, emissions of 

carbon monoxide, volatile organic compounds (which 

lead to the formation of ozone), particulate matter, sulfur dioxide, and nitrogen oxides (which lead to the formation of ozone and particulate matter) decreased by 

differing amounts, ranging from 17 to 44 percent. For 

lead, emissions have decreased by 99 percent, but this 

reduction is based on data that span a longer time 

frame (1970 to 2002). 

Outdoor air concentrations of carbon monoxide, 

lead, nitrogen dioxide, ozone, and particulate 

matter have decreased over the decades during 

which the current nationwide monitoring network has operated. These reductions are consistent 

with the observed decreases in emissions mentioned 

above. In most or all of the United States, outdoor air 

OUTDOOR AIR
 

concentrations of carbon monoxide, lead, and nitrogen dioxide have decreased such that levels now
 

meet EPA’s standards to protect human health and
 

the environment. Though outdoor air concentrations
 

of ozone (see graphic) and particulate matter have
 

decreased nationwide, concentrations still exceed
 

EPA’s standards for either or both pollutants in
 

dozens of metropolitan areas. 


as particulate matter), and sulfur dioxide. These pollutants are often referred to as criteria pollutants. 

Subsequently, EPA identified an additional 188 pollutants 

of concern, called air toxics, that are known or suspected 

to cause cancer, other serious health problems, and 

adverse environmental effects. Examples include benzene, which is found in gasoline; metals such as mercury 

and cadmium; dioxin; and asbestos. 

There are several ways to measure outdoor air pollution 

trends. Emissions can be measured or estimated at their 

source, and concentrations of pollutants in the air can be 

monitored at numerous outdoor locations around the 

country. 

National indicators are not available for other 

aspects of outdoor air quality. While indicators provide insights on emissions and outdoor air concentration trends for many pollutants, monitoring networks 

are not yet extensive enough to determine national 

trends in concentrations for all pollutants, including Concentration (parts per million) 

many air toxics. Further, the indicators are limited in 

quantifying how exposures to single pollutants and 

mixtures of air pollutants affect human health and the 

environment. Although strong evidence links outdoor 

air pollution to health effects at specific locations, few 

long-term studies at a national scale have measured 

the extent to which health effects are linked directly 

to outdoor air quality. 

Ozone Concentrations in Outdoor Air, 

1978-2006 

0.14 

0.12 

90% of sites have concentrations below this line 

10% of sites have 

concentrations 

below this line 

EPA’s air quality 

standard 

0.10 

0.08 

0.06 

0.04 

0.02 

For selected air toxics, emissions due to human 

activities and outdoor air concentrations have 

decreased. Nationwide, emissions summed across all 

188 air toxics decreased between 1990 and 2002. This 

includes a 52-percent reduction in mercury emissions. 

Monitoring networks are extensive enough to determine corresponding national trends in outdoor air concentrations of benzene, which decreased 55 percent 

between 1994 and 2006. 

0.00 

’78-’80 ’82-’84 ’86-’88 ’90-’92 ’94-’96 ’98-’00 ’02-’04 

Concentrations were measured at 201 trend sites nationwide and are 

expressed in terms of EPA’s air quality standard. 

The figure displays the 1997 National Ambient Air Quality Standard 

(0.08 ppm). Future versions of the Report on the Environment will 

compare ozone concentrations to the recently promulgated 2008 

NAAQS (0.075 ppm) or to the NAAQS in effect at the time. 

Source: U.S. Environmental Protection Agency, 2007 

Chapter 1 • Air 5 Outdoor Air 


Average
ACID RAIN AND REGIONAL HAZE
 

Each year in the United States, 

millions of tons of sulfur dioxide 

and nitrogen oxides are released 

into the air from the burning of 

fossil fuels. These pollutants react with other airborne 

substances to form acidic compounds (sulfates and 

nitrates). Acid deposition occurs when these compounds 

fall to the Earth in one of two forms: wet (dissolved in 

rain, snow, and fog) or dry (as gases or particles). Wet 

deposition is more commonly referred to as acid rain. 

Acid deposition is of concern because it can make soils, 

lakes, and streams more acidic, which can harm fish, 

amphibians, water birds, and other species in affected 

areas. It can also damage trees, buildings, monuments, 

KEY POINTS 

Nationwide, emissions of the main pollutants that 

form acid rain decreased between 1990 and 2002. 

Emissions of sulfur dioxide due to human activities 

decreased by 37 percent, and emissions of nitrogen 

oxides due to human activities declined by 17 percent. 

Acid rain, as measured by wet deposition of sulfates and nitrates, decreased across most of the 

country from 1989 to 2006. Consistent with emissions data, average regional decreases in wet deposition of sulfate during this time were 35 percent in the 

Northeast, 33 percent in the Midwest, 28 percent in 

the Mid-Atlantic, and 20 percent in the Southeast (see 

graphic). Wet deposition of nitrate also decreased in 

some parts of the country, but to a lesser extent than 

wet deposition of sulfate. 

painted surfaces, and other materials. Acid rain can be 

tracked in several ways: by evaluating emissions of sulfur 

dioxide and nitrogen oxides (the pollutants that form 

sulfates and nitrates), by monitoring acid rain directly, 

and by measuring the acidity of water bodies. 

The pollutants that form acid rain also form airborne 

particulate matter, which contributes to regional haze. 

Regional haze, tracked by visibility measurements, is 

caused when sunlight encounters tiny airborne particles 

that limit the distance one can see. Regional haze also 

degrades the color, clarity, and contrast of vistas, including those found in many National Parks and Wilderness 

Areas. Certain substances impair visibility more during 

humid conditions. 

Many surface waters in the Adirondack Mountains, 

New England, and the northern Appalachian 

regions became less acidic between the early 1990s 

and 2005. This change corresponds to a decrease in 

acid rain in these regions. While acidic surface waters 

are still found in these areas, some surface waters are 

showing signs of recovery. National indicators are not 

available to track trends in other ways that acid rain has 

harmed the environment or human health. 

Regional haze in 38 National Parks and Wilderness 

Areas improved between 1992 and 2004, with the 

average annual visual range (or distance that one can 

see) gradually increasing. On average, the West has 

substantially better visibility than the East due to regional 

differences in air pollution and the greater humidity in 

the East. National indicators have not been developed to 

track visibility in cities or other populated areas. 

Wet Sulfate Deposition, 1989-1991 Versus 2004-2006 

1989-1991 2004-2006 

Wet sulfate deposition (kilograms per hectare): 

0 4 8 12 16 20 24 28 >32 

Source: National Atmospheric Deposition Program, 2007 

Chapter 1 • Air 6 Acid Rain and Regional Haze
 
Stratospheric ozone over North America decreased 

through the 1980s and early 1990s, but has started 

to recover. Before the late 1970s, there was little 

change, beyond natural variations, in the thickness 

of the ozone layer over North America. Since then, 

the thickness of the ozone layer decreased, reaching its lowest level in 1993 (see graphic), with no 

further decline occurring in more recent years. 

While the ozone layer has begun to recover, ozone 

levels over North America during 2002 to 2005 

were still 3 percent lower, on average, than those 

observed 20 years earlier. 

Tropospheric concentrations of total ozonedepleting substances have been slowly declining. 

Between 1995 and 2006, total ozone-depleting substances in the troposphere have declined 12 percent, 

and this decline has contributed to the recent recovery in stratospheric ozone levels. The trends for individual ozone-depleting substances vary. Tropospheric 

concentrations of many ozone-depleting substances 

have declined since the early 1990s, but concentrations of halons (fire extinguishing agents) and 

hydrochlorofluorocarbons (HCFCs), a class of chemicals being used to replace CFCs, increased. 

Percent change from 1964-1980 levels 

1965 1970 1975 1980 1990 1995 2000 2005

-8 

-6 

-4 

-2 

0 

2 

1985 

Total Ozone Levels Over North America, 

1964-2006 

Total ozone refers to the total 

ozone concentration in a 

column of air between the 

Earth’s surface and the top 

of the atmosphere. 

Source: World Meteorological 

Organization, 2007 

Ozone is a gas present throughout the Earth’s atmosphere. Most 

ozone is concentrated in a layer 

in the stratosphere—a portion of 

the atmosphere many miles above the planet’s surface. 

The ozone layer protects people, animals, plants, and other 

living things by absorbing most of the sun’s harmful ultraviolet radiation, which can lead to more cases of certain 

types of skin cancer and cataracts and can harm crops and 

ecosystems. In contrast, ozone in the troposphere (the portion of the atmosphere from ground level to the stratosphere) is a pollutant that poses a health risk. 

Certain ozone-depleting substances, which are man-made 

and emitted at ground level by sources worldwide, have 

been damaging the ozone layer for many years. Once 

these chemicals rise from the troposphere into the stratosphere, they directly lead to ozone depletion: a thinning of 

the ozone layer over some areas of the world. 

Ozone-depleting substances include chlorofluorocarbons 

(CFCs), which were once extensively used as propellants in 

KEY POINTS 

OZONE DEPLETION
 

spray cans and as refrigerants and solvents. Many countries, including the United States, are phasing out the production and use of CFCs and other ozone-depleting 

substances. Because many of these substances persist in air 

for a very long time, however, the ozone layer will take 

years to recover, even after these chemicals are no longer 

released. 

Ground-based measurement networks and instruments on 

board aircraft, balloons, and satellites are used to monitor 

both the thickness of the ozone layer and concentrations 

of ozone-depleting substances in the troposphere and in 

the stratosphere. 

Chapter 1 • Air 7 Ozone Depletion
 

Ground-based data

Data collected by 

multiple satellites

and reported in four

different studies
Some gases in the atmosphere 

trap part of the Earth’s outgoing 

energy, which causes the atmosphere to retain heat and affect 

climate. These gases are called greenhouse gases, and 

they include carbon dioxide, methane, nitrous oxide, and 

certain man-made chemicals. Some greenhouse gases 

occur naturally, while emissions due to human activities, 

such as electricity production and transportation, add to 

the natural concentrations in the atmosphere. 

Greenhouse gases are important to track because 

increased concentrations due to human activity cause the 

atmosphere to retain heat which, in turn, is affecting 

KEY POINTS 

GREENHOUSE GASES
 

various aspects of climate, such as temperature, evaporation, and precipitation. Natural phenomena, like volcanic 

activity and variations in the sun’s output, and other 

human activities, such as land use changes, also affect climate. Human health, agriculture, water resources, forests, 

wildlife, and coastal areas all can be affected by climate 

change. 

National trends in greenhouse gases are characterized by tracking emissions 

of these gases from human 

activities and concentrations 

of these gases in the air. 

Global atmospheric concentrations of several 

important greenhouse gases have risen substantially over the past 100 years. Measurements of gases 

trapped historically in Antarctic ice confirm that the 

current global atmospheric concentrations of carbon 

dioxide (see graphic) and methane are unprecedented 

over the past 650,000 years, even after accounting for 

natural fluctuations. Concentrations of nitrous oxide 

are 18 percent higher than pre-industrial levels; and 

concentrations of certain synthetic chemicals were 

essentially zero a few decades ago, but increased 

rapidly between 1980 and 2006. 

Between 1990 and 2005, U.S. greenhouse gas emissions from human activities rose 16 percent; the primary source of these emissions was fossil fuel 

combustion. Carbon dioxide, widely reported as the 

most important greenhouse gas, makes up most of this 

increase. Energy use, primarily electricity generation 

and transportation, accounted for approximately 85 

percent of the U.S. greenhouse gas emissions in 2005. 

While trends in U.S. emissions and global atmospheric concentrations of greenhouse gases are 

based on robust data, gaps remain. For both emissions and concentrations, trends have been quantified 

for several of the most important greenhouse gases, 

but not for every greenhouse gas. 

647,426 BC to 339 BC 9002 BC to 1975 AD 1958 AD to 2006 AD 

CO2 concentration (parts per million) 

0 

50 

100 

150 

200 

250 

300 

350 

400 

750,000 BC 

500,000 BC 

250,000 BC 

0

10,000 BC

8000 BC6000 BC

4000 BC2000 BC 

0 

2000 

1955 1965 

1975

1985 1995 2005 

Global Atmospheric Concentrations of Carbon Dioxide (CO2) Over Geological Time and in Recent Years 

The concentration data shown are reported in multiple scientific publications. Complete citations for these peer-reviewed publications are provided in 

the 2008 Report on the Environment. 

Chapter 1 • Air 8 Greenhouse Gases
 
Many substances affect the quality of air inside homes, schools, 

workplaces, and other buildings. 

Some of these contaminants 

come from outdoor air and building materials; others are 

produced by indoor activities such as cooking, smoking, 

and using cleaning materials. Natural substances, such as 

mold, can also affect indoor air quality. 

Indoor air quality is important because Americans, on 

average, spend most of their time indoors. In addition, 

the indoor concentrations of some pollutants can exceed 

levels typically found outdoors. Health effects associated 

with indoor air pollutants include irritation of the eyes, 

nose, and throat; headaches, dizziness, and fatigue; respiratory diseases; heart disease; and cancer. 

KEY POINTS 

INDOOR AIR
 

National indicators are available for two harmful substances found in indoor air: radon and environmental 

tobacco smoke. Radon is a naturally occurring radioactive gas found underground. It can seep into buildings 

through cracks in floors and walls, and is a risk factor for 

lung cancer. For homes with radon levels above EPA’s 

radon action level, EPA recommends that occupants take 

action to protect their health—for example, by installing 

a mitigation system to reduce radon levels. 

Environmental tobacco smoke is associated with numerous health effects, including coughing, heart disease, 

and lung cancer. Children are at particular risk from 

exposure to environmental tobacco smoke because they 

are still developing physically. 

Between 1990 and 2006, both the number of 

homes with radon mitigation systems and the number of homes needing mitigation increased. Homes 

with mitigation systems rose from 175,000 to 714,000, 

and homes needing mitigation increased from 6.4 million to 7.8 million due in part to an increase in housing 

stock, particularly in areas with the highest radon 

potential (see graphic). More than 90 percent of the 

nation’s homes with indoor radon levels at or above 

EPA’s action level do not have mitigation systems, 

though some of these homes have been built with 

new, radon-resistant construction features to reduce 

radon exposures. 

Over the past decade, exposure to environmental 

tobacco smoke among nonsmokers decreased considerably. All population groups, regardless of age, sex, 

or ethnicity, experienced this decrease, which was likely 

due to behavior changes such as reduced smoking and 

smoking restrictions in some public places. Exposure to 

environmental tobacco smoke is measured by blood 

levels of cotinine, a substance produced in the body 

when a person is exposed to nicotine. Among nonsmokers, children, on average, have more than twice 

the level of blood cotinine as adults. 

National indicators currently are not available for 

a broader range of pollutants and substances 

found in indoor air. Scientists have studied numerous other indoor air quality issues, but the available 

information does not track trends over time or across 

the entire nation. 

Homes (millions) 

1990 1992 1994 1996 1998 2000 2002 2004 2006 

0 

1 

2 

3 

4 

5 

6 

7 

8 

Homes above EPA’s radon action level 

Homes with radon mitigation systems

Radon in U.S. Homes, 1990-2006 

Source: U.S. Environmental Protection Agency, 1992, 2007 

Chapter 1 • Air 9 Indoor Air
 
WATER
 

Fresh Surface Waters 

Ground Water 

Wetlands 

Coastal Waters 

Drinking Water 

Recreational Waters 

Consumable Fish and 

Shellfish 

2 

F

rom swiftly flowing streams to slow-moving 

water underground, the nation’s water 

resources are integral to life. Water resources 

encompass water bodies (such as coastal waters, 

lakes, streams, ground water, and wetlands) and 

their associated ecosystems. They sustain a multitude of plant and animal species and provide for 

drinking water, irrigation, fishing, recreation, and 

many other needs. 

The ability of water resources to support these 

functions depends on their extent and condition. 

The extent of a water resource refers to its depth, 

flow, volume, and area. Condition reflects the ability of a water resource to sustain ecological needs 

and human uses. The extent and condition of 

water resources can affect the health and wellbeing of people, ecosystems, and critical environmental processes. 

In addition, because water is constantly cycling 

above and below the surface of the Earth, there are 

many connections between water resources and 

other parts of the environment. For example, fertilizers and pesticides used on land can leach into 

underground or surface water supplies. Also, chemicals released into the air can be deposited, via rain 

or snow, into a lake or stream. 

A variety of methods are used to collect data on 

water resources, including targeted monitoring of 

specific water resources and select sampling of 

locations deemed to be representative of a larger 

area. One of the challenges in assessing the extent 

and condition of water resources is that a single 

data collection method is rarely perfect for every 

situation. This chapter provides an overview of 

national-level trends where nationally consistent 

data are available, but it does not describe the 

extent or condition of local water bodies or the full 

range of variations and extremes that occur within 

individual water bodies. 

Chapter 2: Water 10
 
Lakes, ponds, rivers, and streams 

sustain ecological systems and 

provide habitat for many plants 

and animals. They provide 

drinking water for people and support agriculture, industry, hydropower, recreation, and other uses. Both natural 

processes and human activities influence the condition 

of these waters. For example, discharges of industrial 

contaminants, agricultural and stormwater runoff, air 

pollutants deposited into water, and invasive species can 

all affect water bodies. 

A variety of biological, physical, and chemical characteristics are used to assess the condition of fresh surface 

waters. An important biological characteristic is the presence and diversity of bottom-dwelling (benthic) macroinvertebrate communities, such as insect larvae, mollusks, 

and worms. Some species of macroinvertebrates are 

KEY POINTS 

FRESH SURFACE WATERS
 

more sensitive than others to disturbances in their habitat, 

such as pollution. 

Examples of physical characteristics are depth and flow. 

Major changes in stream flows can affect plant and animal 

species that have adapted to particular seasonal fluctuations in flow, such as those that require a period of low or 

no stream flow in their habitat at a certain time of year. 

Key chemical characteristics include acidity and dissolved 

oxygen. Acidity in soils, lakes, and streams can harm 

aquatic species and ecosystems. Low dissolved oxygen 

content can also be harmful. Excess concentrations of 

the nutrients nitrogen and phosphorus (from sewage or 

agricultural runoff, for instance) can cause algae to 

bloom in water. As the algae die and decompose, they 

deplete the oxygen in the water needed by fish and 

other organisms. 

In about 42 percent of wadeable stream miles, 

benthic macroinvertebrate communities show 

substantial disturbance; about 28 percent show 

little disturbance (see graphic). Low biological diversity potentially indicates substantial pollution and higher 

disturbance. By contrast, communities that are biologically diverse and include many pollution-sensitive 

species likely indicate that a stream is less disturbed. 

Wadeable streams are streams and rivers shallow 

enough to sample without boats. 

Since 1960, more than half of the rivers and 

streams measured nationwide have shown 

major changes in the volume of high and low 

flows over time. In largely arid grasslands and 

shrublands, the percentage of streams with no-flow 

periods decreased slightly between 1960 and 2006, 

along with the average length of no-flow periods. 

Fresh surface waters show a mixed picture of 

chemical condition. Acidity has decreased since the 

early 1990s in lakes and streams in most regions sensitive to acid rain, although one region showed little 

change. Approximately 30 percent of the nation’s 

wadeable stream miles contain high nitrogen and 

phosphorus concentrations. Over the last several 

decades, nitrate loads increased in the Mississippi 

River. Phosphorus loads decreased in the St. 

Lawrence and Susquehanna Rivers, but showed no 

clear trend in the Mississippi or Columbia rivers. 

The extent of surface waters and many key stressors are not currently tracked by national indicators. Key stressors include pollution from various 

sources and toxic contaminants in sediments, which 

can impact water quality and potentially enter the 

aquatic food web. 

41.9% 

24.9% 

28.2% 

5% 

Moderately 

disturbed 

Least 

disturbed 

Not assessed/no data 

Most 

disturbed 

Benthic Community Condition in Wadeable Streams, 

2000-2004 

Data gathered from 2000 to 2004 in the lower 48 states. 

Categories based on the number and diversity of benthic species present, with “least disturbed” being the most diverse. Graphic shows the 

percent of stream miles in each category. 

Source: U.S. Environmental Protection Agency, 2006 

Chapter 2 • Water 11 Fresh Surface Waters
 
More than 1 million cubic miles 

of fresh water lies underground, 

stored in cracks and pores below 

the Earth’s surface. The vast 

majority of the world’s fresh water available for human use 

is ground water, which has 30 times the volume of the 

world’s fresh surface waters. Many parts of the country 

rely heavily on ground water for important needs such as 

drinking water, irrigation, industry, and livestock. 

Some ecological systems also depend on ground water. 

For example, many fish species depend on spring-fed 

waters for their habitat or spawning grounds. Springs 

occur when a body of ground water reaches the Earth’s 

surface. By some estimates, ground water feeds about 

40 percent of total national stream flow, and the percentage could be much higher in arid areas. 

KEY POINTS 

GROUND WATER
 

Human activities and natural factors can affect both the 

extent and condition of ground water. Pesticides, fertilizers, and wastes, as well as natural substances like arsenic, 

can contaminate ground water. For example, fertilizers 

and animal wastes used on land can release nutrients such 

as nitrate, which can seep into ground water. 

Withdrawing too much ground water from a source can 

reduce the water depth in streams and lakes, affecting 

vegetation and wildlife habitat. It can also cause land to 

subside and sinkholes to form. Once depleted, some deep 

aquifers (underground geological formations containing 

water) can take thousands of years to recharge, affecting 

the supply of ground water available for future needs. 

About 60 percent of shallow wells tested in agricultural areas contained pesticide compounds. 

Approximately 1 percent of the shallow wells tested had 

concentrations of pesticides above levels considered safe 

for human health. 

In about 21 percent of shallow wells, average 

nitrate concentrations exceeded the federal 

drinking water standard and were much higher 

than the levels generally found in areas with 

little human influence (see graphic). Public water 

systems must test for nitrate and treat the water if 

levels exceed federal health-based standards. 

The data in this report do not provide information 

about the condition of deeper aquifers, which are 

more likely to be used for public water supplies. 

These data only characterize the uppermost layers 

of shallow aquifers typically used by private wells. 

There are no national treatment or monitoring 

requirements for private wells; however, owners 

should test their water periodically to identify 

possible health risks. 

There are no consistent national indicators for 

many aspects of ground water condition or 

extent. These aspects include the presence of 

chemicals other than nitrates and pesticides in agricultural areas and the condition of ground water in 

predominantly non-agricultural areas, including 

urban areas. Localized events, such as chemical spills 

or leaks from underground storage tanks, can affect 

ground water in urban areas; such events are difficult 

to measure at the national level. 

23.0% 

34.5% 

21.4% 

13.5% 

6 to 

<10 mg/L 

10 mg/L 

or more 

2 to <6 mg/L 

<1 mg/L 

7.7% 

1 to <2 mg/L 

Nitrate Concentrations in Shallow Ground Water 

in Agricultural Watersheds, 1992-2003 

Data gathered in a survey of 1,423 wells in the lower 48 states from 

1992 to 2003. Graphic shows percent of wells in each category. 

The federal drinking water standard for nitrate is 10 milligrams of 

nitrate per liter of water (10 mg/L). 

Totals do not add up to 100% due to rounding. 

Source: U.S. Geological Survey, 2007 

Chapter 2 • Water 12 Ground Water
 
Wetlands—areas that are periodically saturated or covered by 

water—are an important ecological resource. Wetlands are like 

sponges, with a natural ability to store water. They act as 

buffers to flooding and erosion, and they improve the 

quality of water by filtering out contaminants. Wetlands 

also provide food and habitat for many plants and animals, including rare and endangered species. In addition, 

they support activities such as commercial fishing and 

recreation. 

Both losses and gains can occur in wetland extent. Natural 

forces and human activities (such as hurricanes, sea level 

change, and certain agricultural and forestry practices) can 

affect wetlands through increased erosion and sedimentation. Draining or filling wetlands for agriculture or other 

KEY POINTS 

WETLANDS
 

development is the main cause of wetland loss. Gains can 

occur when wetlands are created or restored. 

Changes in the extent or type of wetlands can have 

major ecological impacts. For example, the conversion of 

a forested wetland to shrub 

vegetation can change 

habitat types and alter 

the structure of plant 

and animal communities present. Such a 

conversion can occur 

through natural 

changes in plant communities or by clearing 

trees from a forested 

wetland. 

The overall extent of wetlands in the lower 48 

states declined over the past 50 years. The rate of 

loss has slowed over time, however, and the most 

recent data show a net gain in wetlands acreage 

nationwide (see graphic). Gains and losses vary by 

wetland type. Freshwater ponds account for most of 

the recent gains in wetland acreage. These ponds 

do not perform the same range and type of environmental functions as other types of wetlands that 

have been lost. 

These data do not evaluate wetland quality or 

condition. Wetland condition is difficult to characterize fully, and there is no national indicator to 

measure it directly. This is partly because each 

wetland has unique characteristics, such as the 

movement and abundance of water, the minerals 

in the underlying soil, and the combinations of 

plant and animal species present. 

National data do not capture locations or patterns 

of wetland change. Both are important for understanding condition—for example, whether large 

wetlands are being left intact or are being fragmented 

into smaller pieces that are less connected and, therefore, less able to perform their ecological functions. 

-458,000 

-290,000 

-58,600 

+32,000 

Net change (acres per year) 

1954-1974 1974-1983 1986-1997 1998-2004 

-500,000 

-400,000 

-300,000 

-200,000 

-100,000 

0 

100,000 

Average Annual Change in Wetland Acreage, 

1954-2004 

Data gathered in the lower 48 states. 

Source: U.S. Fish and Wildlife Service, 2006 

Chapter 2 • Water 13 Wetlands
 
Coastal waters—the interface 

between terrestrial environments 

and the open ocean—encompass many unique habitats such 

as estuaries, coastal wetlands, seagrass meadows, coral 

reefs, and mangrove and kelp forests. These ecologically 

rich areas support waterfowl, fish, marine mammals, and 

many other organisms. 

Human activities and natural factors can affect the condition of coastal waters. Sewage overflow, agricultural 

runoff, storms, erosion, and sedimentation can all 

increase the amount of nutrients (such as nitrogen and 

phosphorus) and pathogens (disease-causing organisms) 

in coastal waters. Chemical contamination from industrial activities, electricity generation, and other sources are 

also concerns, as are invasive species and overharvesting 

of fish and other marine species. 

Organisms that live in and on the ocean floor (benthic 

organisms) are a key measure of coastal water condition 

because these organisms are sensitive to pollution. One 

KEY POINTS 

COASTAL WATERS
 

important group of benthic organisms, known as benthic macroinvertebrates, includes worms, clams, crabs, and 

lobsters. 

Scientists monitor several interlinked characteristics of 

water quality in coastal areas: nutrients, chlorophyll-a, 

dissolved oxygen, and water clarity. Plants need nutrients 

to grow, but in excess, nutrients fuel the growth of 

algae. High levels of chlorophyll-a indicate overproduction of algae. Too much algae leads to low levels of dissolved oxygen in the water and decreased water clarity. 

The resulting lack of oxygen and sunlight can harm 

plant and animal life. 

Scientists also monitor plants that grow under water in 

coastal areas, known as submerged aquatic vegetation 

(SAV). Like all plants, SAV needs sunlight to grow and 

survive. Its growth can be affected by excess nutrients, 

as well as suspended sediments (loose particles of clay 

and silt in the water), which can block sunlight from 

reaching the plants. 

Coastal benthic communities in 70 percent of the 

areas sampled showed little evidence of disturbance (see graphic). The benthic communities in these 

areas showed high biological diversity and the presence 

of pollution-sensitive species, likely indicating that the 

waters were relatively unpolluted. 

SAV plays an important ecological role, for 

example, in the Chesapeake Bay, where SAV 

increased from 41,000 to 59,000 acres from 

1978 to 2006. However, current acreage is still less 

than half of the historical coverage (from the mid1930s). The extent of these plants is important 

because the vegetation provides food and habitat for 

many organisms, adds oxygen to the water, filters 

sediments, inhibits wave action that erodes shorelines, and absorbs excess nutrients. 

Elevated levels of nutrients and chlorophyll-a are 

present in slightly less than 10 percent of the 

nation’s coastal waters. However, in areas such as 

the Gulf of Mexico dead zone and Long Island 

Sound, substantial areas of hypoxia (when dissolved 

oxygen is below levels necessary to sustain most 

animal life) are present. 

There are no national indicators for the extent of 

coastal waters and many aspects of their condition. 

For example, there are no national indicators for SAV, 

invasive species, harmful algal blooms, condition of 

coral reefs, or status of coastal fish and shellfish communities. 

70% 

17% 

13% 

Moderately 

disturbed 

Least 

disturbed 

Most 

disturbed 

Benthic Community Condition in Estuarine Waters, 

1997-2000 

Data gathered in the lower 48 states and Puerto Rico from 1997 to 2000. 

Categories based on the number and diversity of benthic species present, 

with “least disturbed” being the most diverse. Graphic shows the percent 

of estuarine area in each category. Estuarine areas are where a freshwater 

stream or river meets the ocean. 

Source: U.S. Environmental Protection Agency, 2004 

Chapter 2 • Water 14 Coastal Waters
 
Virtually all drinking water in the 

United States comes from fresh 

surface water and ground water. 

These source waters can contain 

industrial, domestic, and agricultural contaminants, as well 

as naturally occurring contaminants such as arsenic and 

radionuclides. Also, some contaminants, such as lead from 

corroded pipes, can enter drinking water between the 

treatment plant and the tap. If these contaminants are 

present in drinking water at sufficient levels, they can lead 

to adverse health effects, including gastrointestinal illnesses, nervous system and reproductive effects, and chronic 

diseases such as cancer. 

To protect public health, EPA sets federal health-based 

standards for drinking water for public water systems. 

Public water systems include community water systems— 

systems that supply drinking water to 25 or more of the 

KEY POINTS 

DRINKING WATER
 

same people year-round in their residences. Community 

water systems serve more than 286 million people, or 

about 95 percent of the U.S. population. 

Public water systems must test for regulated contaminants 

and treat the water, if needed, to meet the federal standards. Disinfection of drinking water effectively protects 

against the risk of waterborne diseases such as typhoid, 

cholera, and hepatitis. 

Filtration, required for 

most public water systems that use surface 

water, provides additional protection 

against microbial 

contaminants. 

In 2007, 92 percent of community water system 

customers (262 million people) were served by 

facilities for which states reported no violations of 

EPA’s health-based drinking water standards (see 

graphic). Approximately 24 million people in 2007 were 

served by systems for which states did report violations of these standards. A portion, but not all, of 

these people might have been exposed to contaminants in drinking water at levels above standards. 

Most of these violations involved rules addressing 

microbial contaminants or disinfection byproducts 

(chemicals that can form when disinfectants, such as 

chlorine, react with naturally occurring materials in 

water). The level of health risk associated with violations varies, depending partly on which contaminants were involved, the extent to which a standard 

was exceeded, the extent to which the distribution 

system was affected, and how long the violation 

lasted. Microbial violations, in particular, can be 

short term. 

These data address drinking water from community water systems only. They do not address 

the quality of drinking water that people get from 

nonpublic supplies (such as private wells and 

untreated surface water sources), from public 

water systems serving transient populations (such 

as roadside rest stops and campgrounds), or from 

nonresidential users (such as some workplaces and 

schools). National data are not available for bottled water, which is regulated by the Food and 

Drug Administration. 

Health effects that could be caused by contaminants in drinking water are not currently tracked by 

national indicators. For example, no national indicator 

is available for disease occurrence or outbreaks caused 

by harmful microorganisms in drinking water. 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Percent of community 

water system customers 

* 

1993199419951996199719981999200020012002

2003200420052006

2007 

Population Served by Community Water Systems With 

No Reported Violations of EPA Health-Based Standards, 

1993-2007 

*Several new standards went into effect after December 31, 2001. For the 

years 2002 through 2007, the darker segment at the top of each column 

shows the additional population that would have been served by systems 

with no reported violations if the new standards had not gone into effect. 

Data are presented by EPA fiscal year (October 1-September 30). 

Source: U.S. Environmental Protection Agency, 2007 

Chapter 2 • Water 15 Drinking Water
 
People enjoy many recreational 

activities on the nation’s rivers, 

lakes, and coastal waters. Several 

characteristics determine whether 

these waters are suitable for recreation. For example, the 

levels of chemical contaminants and disease-causing 

microorganisms in water affect whether the water is suitable for swimming, boating, and other contact activities. 

KEY POINTS 

RECREATIONAL WATERS
 

The condition of ecosystems and the wildlife within 

them, which support recreational activities such as fishing and bird watching, is also important. While many of 

these characteristics can be measured at a local level, 

there are several barriers to compiling these data into 

national indicators. 

While information exists about many individual 

water bodies, consistent national indicators for 

recreational waters are not yet available. Many 

states and localities collect information about individual water bodies in their region. States also monitor 

coastal beaches for levels of certain disease-causing 

bacteria and report the results to EPA. However, different states monitor in different ways (for example, by 

using different methods or monitoring more or less 

frequently), making it difficult to compile the results 

into national indicators. 

Improved data collection could lead to suitable 

indicators in several areas. For example, with a 

comprehensive national system for gathering data, 

scientists could develop consistent national indicators 

for bacteria levels at beaches. 

Chapter 2 • Water 16 Recreational Waters
 
CONSUMABLE FISH AND SHELLFISH
 

Fish and shellfish are an important part of a healthy diet for 

many Americans. Some fish and 

shellfish from lakes, rivers, estuaries, and deep ocean fisheries, as well as farmed fish and 

shellfish, can contain chemicals or disease-causing organisms at levels that can pose human health risks. Sources of 

these contaminants include runoff from urban and agricultural areas, pollutants deposited in water from the air, and 

direct discharges into water bodies. 

Concerns about fish and shellfish safety are higher for people who eat a lot of fish and groups of people who are 

particularly vulnerable to contaminants that may be 

KEY POINTS 

present in fish—such as infants, children, the elderly, and 

women who are pregnant or might become pregnant. 

Of particular interest in measuring the condition of consumable fish and shellfish are chemicals such as mercury, 

polychlorinated biphenyls (PCBs), the pesticide DDT or 

dichloro-diphenyl-trichloroethane, and polycyclic aromatic 

hydro-carbons (PAHs), which form during the combustion 

of oil, gas, and other organic substances. These compounds can persist in sediments for a long time, increasing 

their potential for entering the food web and ultimately 

concentrating in fish that may be eaten by people and 

wildlife. 

Estuarine sites (sites in areas where a freshwater 

stream or river meets the ocean) across the nation 

showed varying levels of contamination in fish 

tissue. Sixty-three percent of the sites showed low fish 

tissue contamination, 15 percent showed moderate 

contamination, and 22 percent had high contamination based on health-based consumption guidelines (see graphic). PCBs, mercury, DDT, and PAHs 

were most often responsible for high contamination 

scores. The condition of coastal fish varied greatly 

among different areas of the country. The survey 

did not include Hawaii, the Caribbean, the Pacific 

territories, or Alaska, which is notable because 

Alaska produces more than half the nation’s 

commercial fish. 

Lake fish surveys found that several chemicals, 

including mercury, dioxins and furans, PCBs, and 

DDT, are widely distributed in the nation’s lakes 

and reservoirs. However, some other chemicals, 

including certain pesticides, were detected rarely 

or not at all. These data do not consider whether 

the detected levels are a health concern, as this portion of the analysis is not yet complete. The surveys 

did not include Hawaii, the Caribbean, Alaska, or 

the Great Lakes. 

While fish consumption advisories provide information on fish from many individual water bodies, these advisories cannot be compiled into a 

national indicator of fish and shellfish condition. 

The states and tribes that issue fish consumption advisories use different ways of monitoring waters and 

making advisory decisions, so the information is not 

comparable. 

There are no consistent national indicators for 

disease-causing organisms in fish and shellfish, 

or for the biological and chemical condition of 

commercially farmed fish and shellfish. 

63% 

High 

Low 

15% 

Moderate 

22% 

At least one 

contaminant above 

its guideline range 

All contaminants

below their

At least one guideline ranges

contaminant within

its guideline range, 

but no exceedances

Contaminants in Fish From Estuarine Waters, 1997-2000 

Data gathered in the lower 48 states from 1997 to 2000. 

Categories are based on comparison to EPA’s health risk guidelines for fish 

consumption. Graphic shows the percent of estuarine sites in each category. 

Source: U.S. Environmental Protection Agency, 2004 

Chapter 2 • Water 17 Consumable Fish and Shellfish
 
LAND
 

Land Cover 

Land Use 

Wastes and the Environment 

Chemicals Applied and 

Released to Land 

Contaminated Lands 

3
 

L

and provides food, shelter, fuel, and raw materials for people, as well as habitat for many 

species. It is the source of many resources such 

as minerals, timber, and petroleum and helps to filter the nation’s water and break down wastes and 

chemicals. While the amount of land in the United 

States is relatively constant, how land is used 

changes continuously. Changes in land use affect 

the distribution and nature of land cover (such as 

forests, developed land, and agricultural land) and 

the condition of land and its resources. 

Land is intricately connected to other environmental 

resources and to human health. For example, land 

cover affects the energy exchange between the 

Earth’s surface and atmosphere, which in turn influences climate and weather. Changes in land cover 

can increase or decrease erosion, water runoff, sedimentation, and flooding. Chemicals and wastes can 

affect human health and the environment when 

they are applied to or disposed of on land. 

Many federal agencies with varying responsibilities 

collect data on land resources using satellite 

imagery, national surveys, and regulatory data. 

These data, in general, represent only a small 

sample of the total picture of land cover, land use, 

waste management and disposal, chemicals used 

on land, and land contamination. States also 

collect these kinds of data, but differ in their 

approaches, making it difficult to compile national 

data on land issues. 

Chapter 3: Land 18
 
Land cover is the vegetation and 

other materials, such as rock, snow, 

or pavement, that are present and 

visible on land. Satellite data are frequently used to identify land cover types over large areas. 

Land cover can be grouped into six major categories: forest 

cover, grass cover, shrub cover, developed land, agriculture, 

and other (which includes ice/snow, bare rock, and other 

types of land cover with limited extent). Land cover differs 

from land use. Land cover is physically obvious, while land use 

is determined by a government agency or individual 

KEY POINTS 

Forest cover and agriculture are the two most common 

types of land cover in the United States. In 2001, of the 

approximately 2.3 billion acres of land in the nation, 641 

million acres were forest cover, 449 million acres were agriculture, 419 million acres were shrub, 291 million acres 

were grass, and 103 million acres were developed land. 

These estimates were derived from satellite data. 

Land cover types vary greatly by region (see graphic). 

Forest cover is predominant in the East and Pacific 

Northwest, agriculture and grass cover in the Midwest, and 

shrub cover in the Southwest. 

LAND COVER
 

landowner and might not always be visible. Because of these 

differences, land cover acreages differ from land use acreages 

in the United States. 

A number of factors affect land cover, including geology, climate, population changes, and human activities such as 

industrial and urban development, deforestation or reforestation, water diversion, and road building. The extent and type 

of land cover in an area can affect habitat quality and availability, species distribution, water quality, climate, and distribution 

and movement of chemicals. 

The total amount of forest in the United States 

declined over the last century, but has been increasing 

in recent years. Regional variations exist. Forest cover has 

increased in the Northeast, Mid-Atlantic, and Midwest, and 

decreased in the West and Southwest. 

Comparing and integrating land cover information is 

difficult. Different agencies collect data on land cover, 

often at varying times and for different purposes. These 

agencies also define and classify land cover differently and 

at varying levels of detail. The most recent comprehensive 

data available are from 2001. 

Land Cover, 2001 

Agriculture Developed Other Water 

Cultivated crops High-density (impervious 80%) Perennial ice/snow Open water 

Pasture/hay Medium-density (impervious 50-79%) Barren 

Low-density (impervious 20-49%) Woody wetland Grass cover Open space (impervious <20%) Emergent herbaceous wetland Grassland 

Forest cover 

Shrub cover Deciduous forest 

Shrubland Evergreen forest 

Mixed forest 

Source: U.S. Environmental Protection Agency, 2007 

Chapter 3 • Land 19 Land Cover
 
U.S. lands support many uses, 

including crop production, timber production, livestock grazing, 

recreation, and residential and 

commercial development. Designated through zoning and 

other regulations, these uses are often less physically obvious than land cover. For example, developed land use can 

include land that has visibly developed features, such as 

asphalt, concrete, and buildings, as well as undeveloped 

land designated for residential or transportation use. 

Land use can adversely affect numerous aspects of the 

environment, including air and water quality, habitat availability, and species distribution. In some cases, land use can 

KEY POINTS 

LAND USE
 

also have positive environmental effects, such as when 

communities restore habitats or clean up and redevelop 

contaminated lands. 

Widespread land uses in the United States include 

grazing, timberland, and food crop production. As of 

2003, of the approximately 2.3 billion acres of land in 

the nation, as many as 721 million acres were used for 

grazing, 504 million acres were classified as potentially 

productive forest (known as timberland), 374 million 

acres were used for food crop production, and 108 million acres were used for development. These data are 

based on aerial photo interpretation and ground surveys. 

Land use patterns vary greatly by region of the 

country. More than three-quarters of the nation’s 

grazing land is in the West, while much of the timberland is concentrated in the East and Southeast. 

The amount of land used for crop production and 

pasture has declined since 1982, while the amount 

of developed land has increased and timberland has 

remained constant. Conversions of forest land, cropland, and pastureland have contributed to the increases 

in developed land. Additionally, highly erodable cropland has been removed from production. 

Between 1982 and 2002, the amount of developed 

land in the United States increased at nearly twice 

the rate of the population (see graphic). The amount 

of developed land grew by about 47 percent, while the 

population grew by just over 24 percent. Population 

and development trends varied in different parts of the 

country. For example, in the West, the amount of land 

developed since 1982 closely matched population 

growth, while in the Northeast, the amount of developed land increased at more than three times the rate 

of population growth. 

The data to track land use trends are limited and 

derived from many sources, which inhibits the ability to track changes over time. Various agencies collect land use data, often at different times and for 

different purposes. Classifications of land use can also 

vary, making it difficult to integrate and compare data. 

1982­

1987 

1987­

1992 

1992­

1997 

1997­

2002 

Percent change 

0 

2 

4 

6 

8 

10 

12 

14 

Change in population 

Change in acreage 

of developed land 

Change in Population and Developed Land, 

1982-2002 

Data gathered in the lower 48 states 

and Hawaii, except for 1997-2002, 

when data on developed land were 

not available for Hawaii. 

Source: U.S. Census Bureau, 1996, 2002, 2006; U.S. Department 

of Agriculture Natural Resources Conservation Service, 2000, 

2004 

Chapter 3 • Land 20 Land Use
 
WASTES AND THE ENVIRONMENT
 

The amount, composition, and 

management of wastes provide 

insight into the nation’s efficiency 

in using materials and resources. 

Such information also can be useful in understanding the 

effects of wastes on human health and the environment. 

The type and amount of waste produced in the United 

States varies and can depend on the size and activities of 

an organization. For example, households primarily produce municipal solid waste (paper, packaging, yard trimmings, and other materials) and discard some products 

with potentially hazardous ingredients and small amounts 

of hazardous waste. Commercial and manufacturing entities and institutions produce municipal solid waste, industrial waste, and larger quantities of hazardous waste. 

Hazardous wastes have properties (toxicity, corrosiveness, 

ignitability, reactivity) that make them potentially harmful 

to human health or the environment. 

KEY POINTS 

Activities such as agriculture, construction/demolition, 

mining, and other resource extraction and industrial 

processes generate large quantities of other types of 

waste. Presently, however, the United States regularly collects information on only municipal solid waste and hazardous waste. These two types of waste make up a small 

fraction of all of the waste generated in the country. 

Once wastes are generated, they must be managed—collected, transported, stored, reused, recycled, processed or 

treated, or disposed of. Because wastes can contain hazardous chemicals, their generation and management have 

the potential to contaminate land, air, or water; compromise their use; affect human health; or impact ecological 

condition. For example, the decomposition of certain kinds 

of wastes in landfills is a major source of methane. In contrast, industry has taken steps to reduce certain high-priority chemicals (documented contaminants of air, water, land, 

plants, and animals) found in waste in recent years. 

Since 1990, the per capita municipal solid waste 

generation rate has remained stable at four-andone-half pounds per person per day. As the U.S. 

population has increased, however, the nation has 

steadily generated more municipal solid waste. 

Generation increased from 88 million tons in 1960 to 

251 million tons in 2006. 

Hazardous waste generation has declined. Hazardous 

waste generation dropped from roughly 36 million tons 

in 1999 to 28 million tons in 2005. Recycling or composting of municipal solid waste increased from 6 percent to 33 percent since 1960 (see graphic). Hazardous 

waste recycling rose only slightly between 1999 and 

2005 and remains at less than 10 percent. 

Most waste is still disposed of on land. In 2006, 55 

percent of municipal solid waste was disposed of in 

landfills, compared to 94 percent in 1960 (see graphic). Of the hazardous waste disposed of on land in 

2005, 90 percent was injected deep into the ground in 

permitted wells, and the remaining 10 percent was 

treated and disposed of in a manner to minimize risk to 

human health and the environment. 

Information about many types of waste is not currently available at the national level. Also, data are 

lacking about exposure and the effects of waste and 

management practices on human health and the environment. The potential effects associated with waste 

vary widely and are influenced by the substances or 

chemicals found in waste and how they are managed. Waste (million tons) 

Year

Landfill o dfill o dfill o dfill o dfill or other disposal

0 

50 

100 

150 

200 

250 

300 

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 

Landfill or other disposal 

Recovery 

for recycling Combustion with energy recovery 

Recovery for composting 

Municipal Solid Waste Management, 1960-2006 

Source: U.S. Environmental Protection Agency, 2007 

Chapter 3 • Land 21 Wastes and the Environment
 
CHEMICALS APPLIED AND RELEASED TO LAND
 

Chemicals are commonly used 

in manufacturing, in food and 

consumer products, and in 

efforts to manage diseases. They 

can be intentionally applied to land for purposes of 

increasing crop yields and controlling pests, or in some 

cases, accidentally spilled on land. Some chemicals also 

occur naturally or can enter the environment through 

acts of nature, such as volcanoes and hurricanes. 

Chemicals released or applied to the environment can 

pose a range of challenges to human health and the 

environment. Some chemicals break down quickly in the 

environment, while others, such as persistent, bioaccumulative, and toxic (PBT) chemicals, persist for long periods of time and can accumulate in the food web. 

KEY POINTS 

Some chemicals can lead to health problems if people 

receive sufficient doses. For many other chemicals, 

though, the possible health effects are not yet well 

known. The effects of 

long-term exposure 

to chemicals are 

often unknown. In 

addition, 

some chemicals can harm 

ecosystems, 

such as when 

excess fertilizers are 

carried in runoff, which can affect water quality and 

aquatic life. 

The amount of certain toxic chemicals in industrial waste materials decreased by more than 4 billion pounds (16 percent) between 1998 and 2005 

(see graphic). In 2005, the United States handled 

1.1 billion pounds of PBT chemicals in industrial waste, 

along with 24 billion pounds of other toxic chemicals 

(shown in graphic) that are subject to reporting to EPA 

under the Toxics Release Inventory (TRI) program. The 

metal mining industry has accounted for 35 percent of 

the total TRI chemicals in production-related wastes 

released to the environment since 1998. 

Over the past 45 years, the use of fertilizers, 

including nitrogen, phosphate, and potash, has 

increased nearly three-fold. The combined use of 

these three chemicals rose from 46 pounds per acre 

per year in 1960 to 138 pounds per acre in 2005. 

Nitrogen accounted for the steepest increase. While 

fertilizers are not inherently harmful, they have the 

potential to contaminate ground and surface water 

when applied improperly or in excessive quantities. 

In annual surveys conducted since 1994, 42 to 71 

percent of food samples have shown detectable 

amounts of pesticide residue. A small fraction of 

samples (approximately 1 out of every 500) had pesticides at concentrations that exceeded tolerance levels 

designed to protect human health. Foods tested include 

fruits, vegetables, grains, meat, and dairy products. 

Data about chemicals used on land are limited. Some 

data are available on pesticide and fertilizer use on agricultural lands. Agencies collect national information on 

only a fraction of all chemicals used in the United 

States, however. Consistent national indicators are lacking regarding when, where, and how frequently chemicals are applied to land and the potential impact when 

they contain toxic ingredients. 

Released 

Treated 

Combusted 

for energy 

recovery 

Recycled 

Chemicals (billion pounds) 

0 

5 

10 

15 

20 

25 

30 

35 

9.2 8.6 9.6 8.9 9.0 8.3 8.5 8.2 

3.6 3.4 3.7 3.5 3.7 3.3 3.2 3.0 

8.3 9.1 

13.0 

8.6 8.0 8.2 9.0 8.6 

6.8 6.9 

6.3 

5.2 4.4 4.0 3.8 3.8 

1998 1999 2000 2001 2002 2003 2004 2005 

Disposition of Toxics Release Inventory (TRI) 

Chemical Waste, 1998-2005 

This graph does not include a subset of 

chemicals designated as persistent, bioaccumulative, and toxic (PBT) because 

reporting requirements for PBTs changed 

in 2001. For a graph of PBT trends, see 

the 2008 Report on the Environment. 

Source: U.S. Environmental Protection 

Agency, 2007 

Chapter 3 • Land 22 Chemicals Applied and Released to Land
 
Contaminated lands range from 

abandoned properties in inner 

cities to large areas of land once 

used for industrial or mining 

activities. Improper handling or disposal of toxic and 

hazardous materials and wastes, improper application of 

chemicals to land, deposition of toxic substances on land 

via winds or water, and accidental spills can all contaminate land. Except for spills and natural events, most land 

contamination is the result of historical activities that are 

no longer practiced. 

The Comprehensive Environmental Response, Compensation, and Liability Act, also known as Superfund, and 

KEY POINTS 

CONTAMINATED LANDS
 

the Resource Conservation and Recovery Act (RCRA) are 

two of the major federal laws governing contaminated 

lands to protect human health and the environment. 

The most toxic abandoned waste sites in the nation are 

listed on the Superfund National Priorities List (NPL). 

High-priority facilities subject to cleanup under RCRA are 

included in the RCRA Cleanup Baseline. 

Completing cleanups at these complex sites can take 

years and even decades; therefore, EPA tracks whether 

people are exposed to contamination above levels of 

concern, and whether contaminated ground water is 

spreading above levels of concern. 

Between 2002 and 2007, the percentage of Superfund NPL sites where human exposure to contamination was under control (that is, unlikely to be 

occurring) remained relatively constant at 82 percent (see graphic). The other 18 percent of sites either 

had documented exposure or had not been 

classified yet. 

Between 2000 and 2007, the percentage of RCRA 

Cleanup Baseline sites where human exposure to 

contamination was demonstrated to be under 

control increased from 37 to 93 percent. This 

increase was due to completion of site investigations, 

actions taken to prevent exposure to contamination, 

and further site cleanup. 

Sites where contaminated ground water was 

demonstrated not to be spreading above levels of concern increased from 61 to 70 percent 

of Superfund NPL sites (2002-2007) and from 

32 to 79 percent of RCRA Cleanup Baseline 

facilities (2000-2007). The increases are due to 

completion of site investigations, actions taken to 

mitigate the spread of contaminated ground 

water, and further site cleanup. 

The total number and extent of contaminated 

sites nationwide is not known, nor are their specific 

effects on human health and the environment. 

Although EPA tracks the most contaminated sites 

through the RCRA Cleanup Baseline and Superfund 

NPL, these sites do not represent the full extent of contaminated lands in the United States. Many other sites 

managed by local, state, and other federal authorities 

are not inventoried at the national level. 

Exposure not 

occurring 

Exposure 

likely 

Insufficient 

data 

Number of sites 

0 

500 

1,000 

1,500 

2,000 

2002 

1,494 

2003 

1,494 

2004 

1,494 

2005 

1,544 

2006 

1,554 

2007 

1,554 

120 

175 

109 

158 

101 

146 

148 

161 

113 

172 

109 

163 

1,199 

(80% 

of 

total) 

1,227 

(82% 

of 

total) 

1,247 

(83% 

of 

total) 

1,235 

(80% 

of 

total) 

1,269 

(82% 

of 

total) 

1,282 

(82% 

of 

total) 

Human Exposure to Contamination 

at Superfund National Priorities List (NPL) 

Sites, 2002-2007 

“Exposure likely” means that there is a reasonable expectation that 

humans are exposed to contamination above health-based standards. 

Data are presented by EPA fiscal year (October 1-September 30). 

Source: U.S. Environmental Protection Agency, 2005, 2006, 2007 

Chapter 3 • Land 23 Contaminated Lands
 
Exposure to Environmental 

Contaminants 

Health Status 

Diseases and Health 

Conditions 

HUMAN EXPOSURE 

AND HEALTH 4 

Many factors can influence human health, 

including exposure to environmental contaminants. People can be exposed to environmental contaminants in a variety of ways, and 

many contaminants are known or suspected of 

causing human disease. The relationships among 

environmental contaminants, exposure, and human 

disease are complex, however. Despite these complexities, studying overall patterns of disease or 

exposure helps determine where further study or 

public health interventions could be needed. 

For people to experience adverse health effects from 

exposure to an environmental contaminant, various 

events must occur. First, a contaminant released 

from its source requires some sort of contact (via air, 

water, or land) with a person and then must enter 

the body through inhalation, ingestion, or skin contact. Additionally, a contaminant needs to be present within the body at sufficient doses to ultimately 

result in a health effect. Understanding the connections between environmental exposure and adverse 

health effects is particularly challenging because 

many risk factors other than the environment— 

including genetics, personal behavior, and health 

care—also affect health. 

Exposure and health data are drawn from many 

sources. These include records of vital statistics, such 

as births and deaths; surveys and questionnaires; 

and surveillance activities, such as cancer registries 

and other systems. As used in this report, these data 

are representative of the national population. They 

are not based on data from targeted populations or 

tied to specific exposures or releases. 

At present, trends in national-level exposure and 

health indicators cannot be linked to trends in 

environmental conditions described in other parts 

of this report, or to predict cause-and-effect relationships between environmental contaminant 

exposure and an adverse health effect. Instead, 

these national-level data can help researchers 

track overall trends in population exposure, 

health, and disease, including trends across 

different age, gender, race, and ethnic groups. 

Chapter 4: Human Exposure and Health 24
 
People can be exposed to many 

different contaminants in the 

environment. Although researchers can measure the levels of 

contaminants in air, water, and land, these measurements 

alone cannot reveal whether or how much of those chemicals have contacted or entered people’s bodies. 

Biomonitoring is used to measure internal body levels of 

contaminants (or substances produced when the body 

interacts with contaminants) in human blood, urine, 

KEY POINTS 

EXPOSURE TO ENVIRONMENTAL CONTAMINANTS
 

or tissues. This type of direct measure offers more information about the extent of exposure to people than environmental levels alone. 

Biomonitoring data can help track levels of people’s exposure to environmental contaminants, but cannot be used 

to determine how people might have been exposed to a 

contaminant, or in most cases whether they will become 

sick. Currently, biomonitoring techniques exist for only a 

subset of the many environmental contaminants. 

Blood lead levels show a steady decline since the 

1980s. Lead can harm the brain, nervous system, and 

other organ systems. Children aged 1 to 5 years have 

the greatest health risk from lead exposure because 

their systems are still developing. Between 1999 and 

2002, 1.6 percent of children aged 1 to 5 years had 

elevated blood lead levels, decreasing from 88 percent 

in the late 1970s. The Centers for Disease Control and 

Prevention define elevated blood lead levels as 10 

micrograms of lead per deciliter of blood. 

About 6 percent of women of child bearing 

age had at least 5.8 parts per billion of mercury 

in their blood from 1999 to 2002. EPA has determined that children born to women with blood 

concentrations of mercury above 5.8 parts per billion are at increased risk of adverse health effects. 

Exposure to environmental tobacco smoke 

among nonsmokers decreased considerably in 

the last decade (see graphic). Nonsmokers who 

are exposed to environmental tobacco smoke can 

have elevated levels of cotinine in their blood. 

Cotinine is a substance that forms in the body 

following exposure to nicotine. 

Baseline measurements of exposure are also 

available for other biomonitoring indicators. 

These measurements can be used in the future to 

track possible trends. Baseline measurements are 

available for cadmium, a metal that enters the 

environment through natural and man-made 

processes; phthalates, used to soften and increase 

flexibility of plastics and vinyl; persistent organic 

pollutants (POPs); man-made chemicals (such as 

polychlorinated biphenyls, dioxins, and furans) 

that can remain in the environment for years or 

decades; and pesticides, including chemicals to control 

weeds, insects, and other organisms. 

Biomonitoring data currently have limitations as 

indicators of exposure. Because biomonitoring data 

do not include the sources of exposure, these indicators alone do not indicate whether measured levels 

are related to environmental exposures. 

Percent of children 

0 

20 

40 

60 

80 

100 

Total Black, 

non-Hispanic 

Mexican 

American 

White, 

non-Hispanic 

1988­

1994 

1999­

2002 

1988­

1994 

1999­

2002 

1988­

1994 

1999­

2002 

1988­

1994 

1999­

2002 

63.7 

41.0 

57.9 

59.4 72.8 

5.2 

62.5 

35.5 

23.7 16.5 

36.6 

22.4 

10.7 

41.3 

24.2 19.1 

More than 1.0 ng/mL 

0.05 to 1.0 ng/mL 

Concentration: 

Blood Cotinine Concentrations in Children Aged 4-17 

by Race and Ethnicity, 1988-1994 Versus 1999-2002 

Cotinine concentrations are reported for nonsmoking 

children only. 

Concentrations are measured in nanograms of cotinine 

per milliliter of blood (ng/mL). 

Source: Federal Interagency Forum on Child and Family Statistics, 2005 

Chapter 4 • Human Exposure and Health 25 Exposure to Environmental Contaminants
 
A nation’s health status can be 

measured in many ways. Life 

expectancy and death rates are 

generally regarded as good 

overall measures of population health because they represent the combined effects of many different risk factors. Infant death rates are particularly useful because 

they indicate the current health status of the population, 

predict the health of the next generation, and reflect the 

overall state of maternal health. 

KEY POINTS 

HEALTH STATUS
 

Tracking these kinds of broad health measures helps to 

identify general patterns in the nation’s health status and 

lay a foundation for studying trends in specific diseases 

and conditions. In addition, such tracking can help identify possible environmental factors that could contribute 

to the diseases or conditions that are the leading causes 

of death in the United States. 

Overall, the health of the U.S. population has continued to improve. Mortality rates continue to decline, 

and life expectancy continues to increase, due to factors 

such as improved medical care over the past few 

decades. 

Life expectancies in the United States are lower, 

however, than in many other countries. In 2004, the 

United States ranked 35th in life expectancy for men 

and women among the 192 nations and states that are 

members of the World Health Organization. 

The three leading causes of death in the United 

States—heart disease, cancer, and stroke—remain 

unchanged since 1999. Measures of premature death 

show that injuries are the leading cause of death, followed by cancer and heart disease. 

Infant mortality in the United States shows a longterm decline, although it remains among the highest in the industrialized world at nearly seven deaths 

per every 1,000 live births in 2004. U.S. infant mortality rates were two to three times higher than the lowest 

rates reported worldwide. 

Although national health is generally improving, 

racial, ethnic, and gender differences persist. The 

mortality rate for black infants is still more than twice 

that of white or Hispanic infants. The gap in life 

expectancy between the black and white populations, 

and male and female populations, is approximately 

five years (see graphic). Though the largest decline in 

overall mortality rates has been observed in black 

males, overall mortality in this group continues to be 

highest compared with white males and white and 

black females. Currently, data available for other racial 

or ethnic groups enable only limited analysis. 

Life expectancy and death rates do not address 

other aspects of health such as perceived wellbeing or quality of life. Though life expectancy and 

death rates are widely accepted measures of health 

status, they alone do not completely describe the 

nation’s health. Age (years) 

1940 1950 1960 1970 1980 1990 2000

All groups 

Male (white) 

Female (white) 

Male (black) 

Female (black) 

50 

55 

60 

65 

70 

75 

80 

85 

0 

Life Expectancy at Birth by Race and Sex, 

1940-2004 

Life expectancy is the average 

number of years at birth a person 

could expect to live if current 

patterns in death rates were to 

continue for the rest of that 

person’s life. 

Source: National Center for Health Statistics, 2006, 2007 

Chapter 4 • Human Exposure and Health 26 Health Status 

DISEASES AND HEALTH CONDITIONS
 

Exposure to environmental contaminants has been linked to 

many human diseases and conditions, including cancer, cardiovascular disease, respiratory disease, some infectious 

diseases, and low birthweight. These links have been 

established through well-designed studies with specified 

populations and specific environmental exposures. Many 

other risk factors can also lead to these diseases and conditions, however. For all the diseases and conditions 

KEY POINTS 

described here, exposure to environmental contaminants 

is just one of the possible risk factors. 

Tracking the occurrence of these human diseases and 

conditions at the national level helps identify general 

patterns or trends over time and across subgroups. 

Some notable differences are seen across different age 

groups, races, or ethnic groups for many conditions, 

such as heart and lung conditions, cancer, asthma, and 

some birth outcomes, such as birth defects, pre-term 

deliveries, and low birthweight. 

As the U.S. population ages, many chronic diseases—including various cancers and heart and lung 

diseases—are occurring more frequently in adults. 

For a number of these diseases, however, occurrence 

has stabilized in recent years. The annual incidence 

(proportion of new cases in a year) of cancer increased 

slowly from the early 1970s to the early 1990s and then 

leveled off. Rates for most of the major cardiovascular 

and chronic obstructive pulmonary diseases remained 

fairly constant between 1997 and 2006, though death 

rates associated with these diseases declined. 

There has been a slight overall rise in the incidence 

of cancer in children ages 0 to 19 years since the 

early 1970s. Leukemia and cancers of the brain and 

nervous system remain the leading cancers in children. 

Higher rates of cancer consistently occur among white 

children compared to black children. 

Asthma rates are higher in children and adolescents 

than in adults, with some distinct patterns across 

races (see graphic). Between 1980 and 1996, childhood asthma rates increased about 4 percent each 

year, with no major shifts observed since 1997. Based 

on data from 2006, approximately 10 million children 

(about one in eight) in the United States were reported 

as having been diagnosed with asthma. American 

Indians/Alaska Natives and blacks experience the highest asthma rates compared to those reported in other 

races. Rates are lower in Hispanic/Latino children 

and adults than in non-Hispanics/Latinos. 

No notable patterns were observed for most 

reportable infectious diseases between 1995 and 

2005. However, some increases were reported between 

2002 and 2005 in Lyme disease, Rocky Mountain spotted fever, and Legionnaires’ disease. 

The proportion of mothers that gave birth early 

(before 37 weeks of gestation) increased by 14 

percent from 1990 to 2002, with a smaller increase 

from 1995 to 2004. Data from 1995 to 2004 also 

show that black mothers were about one-and-a-half 

to two times more likely to give birth early than white 

mothers. Also, black babies born at full term were 

more likely to have a low birthweight (less than 2,500 

grams, or 5 pounds 8 ounces) than white babies. 

These indicators provide important insights on disease patterns but cannot be used alone to understand the role of environmental contaminant 

exposures. This is because these diseases and conditions are linked to other causes besides environmental 

exposures. Also, national indicators are not available for 

other diseases with possible links to environmental contaminants, such as behavioral and neurodevelopmental 

disorders, and other diseases still being studied for 

possible connections to environmental contaminant 

exposure, like Alzheimer’s disease and diabetes. 

All groups 

White 

Black 

American Indian/ 

Alaska Native 

Asian

Rate (per 1,000) 

Children 

(0-17 years) 

Adults 

(18+ years) 

0 

40 

80 

120 

160 

200 

Asthma Prevalence by Race, 2003-2005 

Asthma prevalence represents individuals who were ever told that they have 

asthma. 

Data were collected from 2003 to 2005. 

Source: National Center for Health Statistics, 2007 

Chapter 4 • Human Exposure and Health 27 Diseases and Health Conditions
 
ECOLOGICAL
 

CONDITION
 

Patterns in 

Ecological Systems 

Biological Diversity 

Ecological Processes 

Physical and 

Chemical Attributes 

of Ecological Systems 

Ecological Exposure 

to Contaminants 

5 

E

cological condition refers to the state of the 

physical, chemical, and biological characteristics of the environment and the processes and 

interactions that connect them. Ecological condition reflects a wide array of factors, including the 

natural development of plant and animal communities, natural disturbances, resource management, 

pollution, and invasive species. 

One approach to assessing the nation’s ecological 

condition is to examine its essential attributes, 

including the extent, distribution, and diversity of 

ecosystems; ecological processes; physical and 

chemical attributes; and exposure to pollutants. 

Human activities and natural factors can directly or 

indirectly affect one or more of these attributes, 

resulting in changes to an ecological system. For 

example, plant growth might increase in response 

to heavy rainfalls or decrease in response to contaminant exposure. Such changes can affect the 

way an ecosystem functions and can have positive 

or negative consequences for society—such as by 

altering crop, timber, or fishery yields. 

Measuring the nation’s ecological condition is challenging. It is not as straightforward as measuring 

pollutant levels in air, water, and soil. For example, 

there are numerous groups of animals and plants, 

but indicators are available for only some of these. 

Major groups known to be undergoing changes, 

such as amphibians, are not captured by the 

available indicators. 

Chapter 5: Ecological Condition 28
 
Ecological systems—ranging 

from forests and watersheds to 

wetlands and coral reefs—make 

up the environment. Changes in 

patterns of the extent and distribution of ecological systems have a fundamental influence on the health of the 

planet and the people who depend on these systems. 

For example, the extent of a forest affects both air and 

water quality, while the type of trees in a forest influences ecosystem structure and function, including which 

animals and plants are present. 

Ecological systems are not isolated, but connected to one 

another. Connectivity refers to the way in which matter, 

energy, and organisms flow within and among ecosystems. 

Fragmentation refers to the breaking up of an ecological 

system into smaller, more isolated parts. When ecological 

systems become fragmented, habitat is broken up into 

KEY POINTS 

PATTERNS IN ECOLOGICAL SYSTEMS
 

patches interspersed with other habitat types that might 

not support the species that were originally present. 

Patterns in ecological systems can change in response to 

natural factors as well as human activities. Natural 

changes can occur gradually as a result of geological and 

climatic changes, or more quickly due to events such as 

extreme weather or wildfires. Human activities that can 

affect ecological systems include urbanization, agriculture, forest management, introduction of invasive species, 

and the release of greenhouse gases, which contributes 

to climate change. 

The impact of such changes varies depending on the geographic scale. For example, a storm could create a gap in a 

forest canopy that only affects the immediate area for several decades. In contrast, widespread loss of wetlands over 

a large region could permanently shift bird migration 

routes or make coastlines more vulnerable to hurricanes. 

The total acreage of forest land nationwide 

declined between the 1930s and the 1970s, but 

increased over the last three decades. Trends in 

forest acreage vary by region and by forest type. For 

example, in the West, the acreage of fir-spruce and 

hardwood forest increased over the past 50 years, 

while the extent of other forest types, including 

many pine forests, decreased (see graphic). 

Slightly more than 26 percent of the forest land in 

the lower 48 states occurs in landscapes completely 

dominated by forest, while 19 percent of forest land 

is considered highly fragmented. Forests can be 

fragmented by human 

activities and by natural 

factors such as forest fires. 

Some ecological systems 

remain highly connected 

and intact. In the Northeast and Mid-Atlantic and 

on the West Coast, roughly 30 percent or more of 

forest land remains unfragmented. In the Southeast, 

forests, wetlands, and 

open water ecological 

systems remain connected 

to each other across 43 

percent of the landscape. 

Little information is available on the extent of 

ecological systems other than forests and wetlands, or about the effects of fragmentation on 

biodiversity and ecological processes at different 

geographic scales. 

Timberland Area in the West by Forest Type, 1953-2002 

Graphic depicts data for states in the western United States (including Alaska and 

Hawaii), based on U.S. Department of Agriculture Forest Service reporting regions 

(see map at right). Forest type is measured only on timberland, which is forest 

that could potentially be used to produce commercial timber. Timberland covers 

39 percent of the forested land in the West. 

Source: U.S. Department of Agriculture Forest Service, 2001, 2004 

Chapter 5 • Ecological Condition 29 Patterns in Ecological Systems
 

0

10

20

30

40 Douglas-fir

Area (million acres)

Ponderosa-Jeffrey 

pine

Fir-spruce Hemlock-Sitka 

spruce

East West

1953

1963

1977

1987

1997

2002

1953

1963

1977

1987

1997

2002

1953

1963

1977

1987

1997

2002

1953

1963

1977

1987

1997

2002

1953

1963

1977

1987

1997

2002

1953

1963

1977

1987

1997

2002

Lodgepole pine Western hardwood 

types
Biological diversity, or biodiversity, refers to the amount of variation within biological systems. 

This diversity occurs on multiple 

levels—from the genetic makeup of a single organism to 

the composition of an entire ecosystem. Biological diversity provides many tangible benefits to society, including 

medicines and crops; for many people, it also contributes 

in important ways to the quality of life. 

Trends in the number and composition of species within 

an ecological system are important indicators of the system’s health and robustness. Scientists generally agree 

that as the number of species in an ecological system 

declines, the system is less able to recover from stress. 

These relationships are not straightforward and can vary 

in degree, depending on the types of species introduced or removed from a system. 

Diversity arises over time when adaptation results in new 

species that fill available niches in the environment. This is 

a dynamic process involving colonization, evolution of 

KEY POINTS 

BIOLOGICAL DIVERSITY
 

species adapted to new conditions, and extinction of 

species that are less well adapted to a changing environment. This process has occurred over millions of years 

across large geographic areas, punctuated occasionally 

by significant natural events such as meteor strikes, periods of intense volcanic activity, and ice ages. 

Human activities—such as urbanization, water management, and land use changes—can have profound effects 

on biological diversity, and in a much shorter timeframe. 

For example, in sewage-polluted waters, dense beds of a 

single species, sludgeworms, can replace 

the more diverse communities of bottom-dwelling organisms ordinarily 

present. Invasive species also can 

have widespread effects. As the 

sea lamprey spread through 

the Great Lakes in the mid-20th 

century, for instance, sweeping 

changes occurred throughout the 

entire food web. 

Watersheds covering almost one-quarter of the 

area of the lower 48 states have lost at least onetenth of the native freshwater fish species known 

to have been present at some time prior to 1970. 

Losses are especially severe in the Southwest and the 

Great Lakes, where eight watersheds have lost more 

than half their native fish species. Fish diversity can 

decline for a number of reasons, such as pollution, 

habitat alteration, fisheries management, and invasive species. In contrast, watersheds covering 

about 21 percent of the lower 48 states have 

retained all of their native species. 

In recent years, changes (both decreases and 

increases) have occurred in bird populations 

in various habitats. Changes in bird populations 

reflect changes in landscape and habitat, food availability and quality, toxic chemical exposure, and 

climate. Since 1966, substantial decreases occurred 

in 70 percent of grassland species and 36 percent of 

shrubland species. Substantial increases occurred in 

40 percent of urban species and 38 percent of water 

and wetland species (see graphic). 

For several aspects of biological diversity, there 

are no consistent national indicators. These 

include major groups of animals such as amphibians, 

reptiles, and mammals; plants; and the numbers of 

threatened, endangered, and invasive species. 

Change in Bird Populations by Habitat Type, 1966-2003 

Data gathered by the North American Breeding Bird Survey, which covers 

the lower 48 states and southern Canada. 

Substantial increases or decreases are those in which the observed 

populations increased or decreased by more than two-thirds. 

Source: Audubon Society, 2004 

Chapter 5 • Ecological Condition 30 Biological Diversity
 

Habitat type

Number of species

0

25

50

75

100

125

150

175

200

Substantial increase

Substantial decrease

No substantial change

Population change:

Grassland Shrubland Woodland Urban Water/

wetland
Ecological systems are sustained 

by biological, physical, and 

chemical processes. One such 

process is carbon cycling. 

During photosynthesis, plants use the sun’s energy to 

produce organic matter from carbon dioxide. This 

organic matter provides the food at the base of the food 

web. Carbon dioxide is regenerated through the respiration of animals in the food web and through decomposition by the microbial community when organisms die. 

Organisms that produce organic matter from inorganic 

matter using energy from the sun are known as primary 

producers. They range in size from microscopic ocean 

plants to the giant redwoods of California. Decreases in 

primary production affect all the animal populations that 

KEY POINTS 

ECOLOGICAL PROCESSES
 

depend on that production for food. Too much primary 

production (for example, algal blooms in water bodies) is 

also a problem. 

Many human and natural factors impact ecological 

processes, including pollution and changes in land use, 

such as conversion of forests to urban or agricultural 

land. Trends in ecological processes, such as the cycling 

of carbon and carbon storage, provide insight into the 

structure and function of ecological communities and 

how human and natural factors affect them. 

Although there are numerous components of the carbon 

cycle, an indicator is available for only one of these components—carbon storage in forests. This indicator provides insight into a portion of the carbon cycle for forest 

ecosystems. 

Overall, the net storage of carbon in U.S. forests 

has been positive since 1953. The rate of storage 

increased between the 1950s and 1980s, but declined 

from 1987 to 1996. Net storage reflects the growth of 

trees minus the amount of carbon lost through harvesting, land use change, or disturbances such as fire, 

insects, and disease. The greatest amount of carbon is 

being stored in the North, followed by the Rocky 

Mountain region. Carbon storage has decreased in the 

South, possibly due to an increase in harvesting compared to growth (see graphic). 

A number of gaps exist in understanding trends in 

ecological processes. Currently, no reliable national 

indicators are available for primary production, nutrient retention and processing, or reproduction and 

growth rates for plant and animal populations. There 

are also no national indicators for other functions that 

ecosystems perform, such as the provision of natural 

resources and regulation of air and water quality. No 

indicator is available for carbon stored in forest soil or 

in other ecosystems. 

Average annual net carbon storage 

(million metric tons per year) 

-25 

0 

25 

50 

75 

100 

1953-1962 1963-1976 1977-1986 1987-1996 

Rocky 

Mountains 

North 

South 

North 

South 

Rocky 

Mountains 

Pacific 

Coast 

Carbon Storage in Forests by Region, 1953-1996 

Data gathered in the lower 48 states. Carbon storage is measured only on timberland, 

which is forest that could potentially be used to produce commercial timber. 

Timberland covers about two-thirds of the forested land of the lower 48 states. 

Source: U.S. Department of Agriculture Forest Service, 2004 

Chapter 5 • Ecological Condition 31 Ecological Processes
 
Physical attributes of ecological 

systems include air temperature, 

light, rainfall, and sea level. 

Chemical attributes include dissolved oxygen, nutrient levels, acidity, and salinity. These 

attributes shape evolution, drive ecological processes, 

and govern the nature of ecological systems. Even small 

changes in these attributes, such as changes in the acidity of a stream or the timing of rainfall in a desert, can 

have potentially large effects on ecological systems. 

As species evolve, they respond to and reflect the physical 

and chemical attributes of the ecological systems in which 

they live. For example, species that evolved in tropical 

KEY POINTS 

PHYSICAL AND CHEMICAL ATTRIBUTES OF ECOLOGICAL SYSTEMS
 

waters require higher, less variable temperatures than 

species that evolved in temperate waters, where average 

temperatures are lower and fluctuate more. Similarly, periodic floods or fires are essential to sustain many species in 

areas where such events have occurred over thousands or 

millions of years. 

Many factors can alter the physical and chemical characteristics of ecological systems. For example, acid rain can 

increase the acidity of lakes in some regions. Damming or 

channelizing rivers can alter the flooding and sedimentation 

processes that sustain particular types of systems, such as 

wetlands. Changes in climate can alter species diversity and 

nearly every aspect of ecological structure and function. 

Since 1901, U.S. and global temperatures have 

risen at an average rate of 0.12°F per decade (see 

graphic). Lately, the rate of warming has increased. 

Over the last 30 years, temperatures rose by 0.59°F per 

decade in the lower 48 states and 0.31°F per decade 

worldwide (see graphic). These trends are consistent 

with reduced snow cover, earlier spring ice melt, and 

increased sea surface temperature, all of which can 

affect ecological systems. It is very likely that most of 

the observed temperature increase is due to rising levels of greenhouse gases in the atmosphere caused by human activities. 

Sea levels rose steadily at many coastal locations 

between 1950 and 1999, particularly the MidAtlantic coast (3 to 6 millimeters per year) and at 

two sites in Louisiana (as high as 9 to 12 millimeters per year). These rates are based on tidal gauges 

that measure relative sea level rise, which accounts for 

sea and land height changes but does not distinguish 

between the two. Sea level rise can alter ecological 

conditions in coastal areas. Effects can include 

increased flooding and loss of freshwater systems as 

they are transformed into inland salt waters or open 

coastal waters. 

About 25 percent of the nation’s small streams 

show strong evidence of excess fine sediments, 

which can diminish habitat for aquatic life. Various 

land use practices, as well as modifications in stream 

flows, can lead to excess sedimentation in streams. 

Gaps remain in assessing national trends in the 

physical and chemical attributes of ecological systems. Recent monitoring programs have provided a 

baseline for national trends in nutrients, acidity, and 

other factors in streams and estuaries. However, there 

still is a lack of trend data or historical baselines for 

some attributes, such as water levels in lakes, amount of 

snowpack, and long-term patterns of flooding and fires. 

Anomaly (degrees Fahrenheit) 

U.S. temperature anomalies 

Anomaly (degrees Fahrenheit) 

Global temperature anomalies 

Year

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 

-3 

-2 

-1 

0 

1 

2 

3 

-3 

-2 

-1 

0 

1 

2 

3 

Year

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 

U.S. and Global Mean Temperatures, 1901-2006 

U.S. data gathered in the lower 48 states. 

“Anomaly” is the difference between the observed temperature and a 

standard that was chosen for comparison. In this case, the standard 

is the average temperature over the period 1961-1990. 

Source: National Oceanic and Atmospheric Administration, 2007 

Chapter 5 • Ecological Condition 32 Physical and Chemical Attributes of Ecological Systems 

ECOLOGICAL EXPOSURE TO CONTAMINANTS
 

Plants and animals can be 

exposed to chemicals in the 

environment through air, water, 

soil, and food. If concentrations 

of these chemicals are too great, the reproduction, 

health, or survival of the individual plant or animal—or 

organisms that consume it—can be threatened. If 

enough individuals in a species (or more than one 

species) are affected, changes in the ecosystem structure 

and function can result. 

KEY POINTS 

Once inside an organism, certain chemicals build up over 

time with repeated exposure. This process is called bioaccumulation. Exposure to these chemicals can be determined by measuring chemical concentrations in plant and 

animal tissues. Other chemicals do not bioaccumulate but 

can still cause harm. For example, 

ozone pollution can damage 

the leaves of plants. Direct 

observations can indicate 

exposure to contaminants 

if the damage is visible. 

In many areas of the country, at least 20 percent of ozone-sensitive forest plants show at 

least some injury from ozone pollution (see 

graphic). The Mid-Atlantic and Southeast show the 

highest levels of injury, while the Rocky Mountains 

and Pacific Northwest show no damage. Ozone 

pollution in the lower atmosphere can affect 

forest ecosystems. Damage to leaves is usually 

the first visible sign of injury to plants from ozone 

exposure. 

Tissues from both coastal and freshwater 

fish contain bioaccumulative chemicals, such 

as the pesticide DDT or dichloro-diphenyltrichloroethane, mercury, and polychlorinated 

biphenyls (PCBs). While exposure to these chemicals is occurring at variable levels throughout the 

country, scientists have not fully assessed the ecological effects of these exposures. These chemicals 

are known to affect coastal and freshwater fish 

species, but there are currently no national threshold levels for harmful effects to fish. 

No consistent national indicators are available 

that measure the level of chemicals in plants or 

in wildlife other than fish. Therefore, no national 

trends are available for exposure of plants and animals to many common environmental pollutants. 

10 

9 

9 

6 

7 

4 

8 10 

5 3 

2 1 

EPA Regions 

2 

Degree of injury: 

None 

Low 

Moderate 

High 

Severe 

Region 1 Region 2 Region 3 

Region 4 Region 5 Region 6 

Region 7 Region 8 Region 9 Region 10

Ozone Injury to Forest Plants by EPA Region, 2002 

Data gathered from 945 monitoring sites 

in 41 states. Graphic shows the percent 

of monitoring sites in each category. 

Source: U.S. Department of Agriculture 

Forest Service, 2006 

Chapter 5 • Ecological Condition 33 Ecological Exposure to Contaminants
 
LOOKING AHEAD
 

Written for a general audience, EPA’s 2008 Report on the Environment: Highlights 

of National Trends summarizes some of the more important findings from a 

more comprehensive companion report, EPA’s 2008 Report on the Environment. 

The topics presented in this document provide important insight into what 

scientists know—and do not know—about current conditions and trends for the 

nation’s air, water, land, human health, and ecological systems. 

This information is based on environmental indicators and is presented at a 

national or regional level. Many other sources on the environment are available, 

including some that address issues at a more local level: 

•	 EPA’s Web site, www.epa.gov, is a good starting place to get more information 

on a particular topic or on a specific city or region of the country. 

•	 Links to individual state environmental departments are available at: 

www.epa.gov/epahome/state.htm. 

•	 Links to some actions that individuals can take to protect the environment 

and their own health are available at: www.epa.gov/roe. 

EPA is just one of many organizations working to fill the gaps in our understanding of the environment. As those gaps are filled, a more complete 

picture of the nation’s environment will emerge. 

EPA plans to report periodically on the state of the environment through 

publications like this one. In addition, the electronic version of the report 

(www.epa.gov/roe) will present new data as they become available and 

allow users to offer suggestions for making this report more useful. Your 

input is welcome. 

ABOUT THE INDICATORS 

The content of Highlights of National Trends is derived from EPA’s 2008 Report 

on the Environment, which features detailed information on 85 environmental 

indicators. Most of these indicators are national in scope; however, regional 

indicators have been used in some cases to illustrate important scenarios and 

could be applied to the nation in the future. A subset of these indicators is 

presented in this document. 

EPA selected indicators to highlight in this document based on their completeness, importance to the public and the scientific community, ability to show a 

meaningful trend, and ability to address a key environmental question. 

Indicators developed since EPA’s Draft Report on the Environment 2003 were 

also given priority. 

ENVIRONMENTAL INDICATORS 

The indicators used in the Report on the Environment: • Are national (or in some cases regional) in coverage. 

They do not describe trends or conditions for a specific • Rely on actual measurements of environmental and locale. human health conditions over time. 

• Come from many governmental and non-governmental • Meet a set of standards, which include quality, accura­ organizations, which collect data at different time peri­ cy, relevance, and comparability. ods and for varying purposes. 

• Were reviewed by an independent scientific panel to 

• Can only partially answer the key questions. ensure that they meet these standards. 

Looking Ahead 	 34
 
LIST OF INDICATORS 

Indicators included in EPA’s 2008 Report on the Environment are listed below, along with the key environmental question each indicator 

attempts to answer. Indicators with an asterisk* are featured in Highlights of National Trends. 

AIR 

OUTDOOR AIR 

What are the trends in outdoor 

air quality and their effects on 

human health and the 

environment? 

• Carbon Monoxide Emissions* 

• Ambient Concentrations of 

Carbon Monoxide* 

• Lead Emissions* 

• Ambient Concentrations of Lead* 

• Nitrogen Oxides Emissions* 

• Ambient Concentrations of 

Nitrogen Dioxide* 

• Volatile Organic Compounds 

Emissions* 

• Ambient Concentrations of 

Ozone* 

• Ozone Injury to Forest Plants 

• Particulate Matter Emissions* 

• Ambient Concentrations of 

Particulate Matter* 

• Sulfur Dioxide Emissions* 

• Percent of Days With Air Quality 

Index Values Greater Than 100 

• Mercury Emissions* 

• Air Toxics Emissions* 

• Ambient Concentrations of 

Benzene* 

• Ozone and Particulate Matter 

Concentrations for U.S. Counties 

in the U.S./Mexico Border 

Region 

• Ambient Concentrations of 

Manganese Compounds in EPA 

Region 5 

ACID RAIN AND REGIONAL HAZE 

What are the trends in outdoor 

air quality and their effects on 

human health and the 

environment? 

• Nitrogen Oxides Emissions* 

• Regional Haze* 

• Sulfur Dioxide Emissions* 

• Acid Deposition* 

• Lake and Stream Acidity* 

• Particulate Matter Emissions 

OZONE DEPLETION 

What are the trends in outdoor 

air quality and their effects on 

human health and the 

environment? 

• Concentrations of OzoneDepleting Substances* 

• Ozone Levels Over North 

America* 

GREENHOUSE GASES 

What are the trends in greenhouse gas emissions and 

concentrations? 

• U.S. Greenhouse Gas Emissions* 

• Atmospheric Concentrations of 

Greenhouse Gases* 

INDOOR AIR 

What are the trends in indoor 

air quality and their effects on 

human health? 

• U.S. Homes Above EPA’s Radon 

Action Level* 

• Blood Cotinine Level* 

WATER 

FRESH SURFACE WATERS 

What are the trends in the extent 

and condition of fresh surface 

waters and their effects on human 

health and the environment? 

• High and Low Stream Flows* 

• Streambed Stability in 

Wadeable Streams 

• Lake and Stream Acidity* 

• Nitrogen and Phosphorus in 

Wadeable Streams* 

• Nitrogen and Phosphorus in 

Streams in Agricultural 

Watersheds 

• Nitrogen and Phosphorus Loads 

in Large Rivers* 

• Pesticides in Streams in 

Agricultural Watersheds 

• Benthic Macroinvertebrates in 

Wadeable Streams* 

GROUND WATER 

What are the trends in the 

extent and condition of ground 

water and their effects on 

human health and the 

environment? 

• Nitrate and Pesticides in Shallow 

Ground Water in Agricultural 

Watersheds* 

WETLANDS 

What are the trends in the 

extent and condition of wetlands and their effects on 

human health and the 

environment? 

• Wetland Extent, Change, and 

Sources of Change* 

COASTAL WATERS 

What are the trends in the 

extent and condition of coastal 

waters and their effects on 

human health and the 

environment? 

• Wetland Extent, Change, and 

Sources of Change 

• Trophic State of Coastal Waters* 

• Coastal Sediment Quality 

• Coastal Benthic Communities* 

• Coastal Fish Tissue Contaminants 

• Submerged Aquatic Vegetation 

in the Chesapeake Bay* 

• Hypoxia in the Gulf of Mexico 

and Long Island Sound* 

DRINKING WATER 

What are the trends in the 

quality of drinking water and 

their effects on human health? 

• Population Served by 

Community Water Systems 

With No Reported Violations of 

Health-Based Standards* 

RECREATIONAL WATERS 

What are the trends in the condition of recreational waters 

and their effects on human 

health and the environment? 

There are currently no national 

indicators available for this topic. 

CONSUMABLE FISH AND 

SHELLFISH 

What are the trends in the condition of consumable fish and 

shellfish and their effects on 

human health? 

• Coastal Fish Tissue 

Contaminants* 

• Contaminants in Lake Fish 

Tissue* 

LAND 

LAND COVER 

What are the trends in land cover 

and their effects on human 

health and the environment? 

• Land Cover* 

• Forest Extent and Type* 

• Land Cover in the Puget 

Sound/Georgia Basin 

LAND USE 

What are the trends in land use 

and their effects on human 

health and the environment? 

• Land Use* 

• Urbanization and Population 

Change* 

List of Indicators 35
 
WASTES AND THE 

ENVIRONMENT 

What are the trends in wastes 

and their effects on human 

health and the environment? 

• Quantity of Municipal Solid 

Waste Generated and Managed* 

• Quantity of RCRA Hazardous 

Waste Generated and Managed* 

CHEMICALS APPLIED AND 

RELEASED TO LAND 

What are the trends in chemicals used on the land and their 

effects on human health and 

the environment? 

• Fertilizer Applied for Agricultural 

Purposes* 

• Toxic Chemicals in ProductionRelated Wastes Combusted for 

Energy Recovery, Released, 

Treated, or Recycled* 

• Pesticide Residues in Food* 

• Reported Pesticide Incidents 

CONTAMINATED LANDS 

What are the trends in contaminated lands and their effects 

on human health and the 

environment? 

• Current Human Exposures 

Under Control at High-Priority 

Cleanup Sites* 

• Migration of Contaminated 

Ground Water Under Control at 

High-Priority Cleanup Sites* 

HUMAN EXPOSURE 

AND HEALTH 

EXPOSURE TO ENVIRONMENTAL 

CONTAMINANTS 

What are the trends in human 

exposure to environmental 

contaminants including across 

population subgroups and 

geographic regions? 

• Blood Lead Level* 

• Blood Mercury Level* 

• Blood Cadmium Level 

• Blood Cotinine Level* 

• Blood Persistent Organic 

Pollutants Level* 

• Urinary Pesticide Level* 

• Urinary Phthlate Level* 

HEALTH STATUS 

What are the trends in health 

status in the United States? 

• General Mortality* 

• Life Expectancy at Birth* 

• Infant Mortality* 

DISEASES AND HEALTH 

CONDITIONS 

What are the trends in human 

disease and conditions for 

which environmental pollutants 

may be a risk factor, including 

across population subgroups 

and geographic regions? 

• Cancer Incidence* 

• Childhood Cancer Incidence* 

• Cardiovascular Disease 

Prevalence and Mortality* 

• Chronic Obstructive Pulmonary 

Disease Prevalence and Mortality* 

• Asthma Prevalence* 

• Infectious Diseases Associated 

With Environmental Exposures or 

Conditions* 

• Birth Defects Prevalence and 

Mortality 

• Low Birthweight* 

• Preterm Delivery* 

ECOLOGICAL 

CONDITION 

PATTERNS IN ECOLOGICAL 

SYSTEMS 

What are the trends in the 

extent and distribution of the 

nation’s ecological systems? 

• Land Cover 

• Forest Extent and Type* 

• Forest Fragmentation* 

• Wetland Extent, Change, and 

Sources of Change 

• Land Use 

• Urbanization and Population 

Change 

• Land Cover in the Puget 

Sound/Georgia Basin 

• Ecological Connectivity in EPA 

Region 4* 

• Relative Ecological Condition 

of Undeveloped Land in EPA 

Region 5 

BIOLOGICAL DIVERSITY 

What are the trends in the diversity and biological balance of the 

nation’s ecological systems? 

• Coastal Benthic Communities 

• Benthic Macroinvertebrates in 

Wadeable Streams 

• Bird Populations* 

• Fish Faunal Intactness* 

• Submerged Aquatic Vegetation 

in the Chesapeake Bay 

• Non-Indigenous Species in the 

Estuaries of the Pacific Northwest 

ECOLOGICAL PROCESSES 

What are the trends in the ecological processes that sustain 

the nation’s ecological systems? 

• Carbon Storage in Forests* 

PHYSICAL AND CHEMICAL 

ATTRIBUTES OF ECOLOGICAL 

SYSTEMS 

What are the trends in the critical physical and chemical 

attributes and processes of the 

nation’s ecological systems? 

• U.S. and Global Mean 

Temperature and Precipitation* 

• Sea Surface Temperature 

• High and Low Stream Flows 

• Streambed Stability in 

Wadeable Streams* 

• Sea Level* 

• Nitrogen and Phosphorus Loads 

in Large Rivers 

• Nitrogen and Phosphorus in 

Streams in Agricultural 

Watersheds 

• Nitrogen and Phosphorus in 

Wadeable Streams 

• Lake and Stream Acidity 

• Hypoxia in the Gulf of Mexico 

and Long Island Sound 

ECOLOGICAL EXPOSURE TO 

CONTAMINANTS 

What are the trends in biomeasures of exposure to common 

environmental pollutants in 

plants and animals? 

• Coastal Fish Tissue 

Contaminants* 

• Ozone Injury to Forest Plants* 

• Contaminants in Lake Fish 

Tissue* 

List of Indicators 36
 
ACKNOWLEDGEMENTS

HIGHLIGHTS DOCUMENT TEAM

Ethan McMahon (EPA)

Project Lead

Suzanne Annand (EPA) 

Gerry Bakker (EPA) 

Gail Bentkover (EPA)

Vipul Bhatt (EPA)

Paul Borst (EPA)

Ethel Brandt (EPA)

Gerard Bulanowski (EPA)

Deborah Burgin (EPA)

Lael Butler (EPA)

Robert Cassell (EPA)

Heather Case (EPA) 

Arden Calvert (EPA)

Andrea Cherepy (EPA)

Julie Damon (EPA)

Nicoletta DiForte (EPA)

Sandra Duque (EPA) 

Rick Durbrow (EPA) 

Vance Fong (EPA)

Tom Forbes (EPA)

Debra Forman (EPA)

Michael Hadrick (EPA)

Belinda Hawkins (EPA)

Michelle Hiller-Purvis (EPA)

Matt Hoagland (EPA)

Elizabeth Jackson (EPA)

Marjorie Jones (EPA)

Monica Jones (EPA)

Stuart Kerzner (EPA)

Carrie Knowlton (EPA)

Danelle Lobdell (EPA)

Macara Lousberg (EPA)

Maricruz MaGowan (EPA)

Lawrence Martin (EPA)

Carmen Maso (EPA)

Jeff Maurer (EPA)

Ronald McHugh (EPA)

Jay Messer (EPA)

Patricia Murphy (EPA) 

Laura Neilsen (EPA)

William Nickerson (EPA)

Nicole Paquette (EPA)

Randolph Perfetti (EPA)

William Rhea (EPA)

Denice Shaw (EPA) 

Madalene Stevens (EPA) 

Richard Sumpter (EPA)

Guy Tomassoni (EPA)

Winona Victery (EPA)

Beth Walls (EPA)

Nancy Wentworth (EPA) 

Sherri White (EPA)

Ann Williamson (EPA)

Arleen O’Donnell 

Massachusetts DEP

Co-chair

Don Watts 

New Jersey Institute of

Technology 

Co-chair

Jeff Crane

Colorado Watershed Assembly

Carolyn Green

Sunoco

John Howard 

Vinson & Elkins

NACEPT Chair

George Lambert

University of Medicine and

Dentistry of New Jersey

SAB member

Stan Laskowski

University of Pennsylvania

Robert Olson 

Institute for Alternative Futures

Bradley Smith

Western Washington University

Victoria Tschinkel 

1000 Friends of Florida

Robert Twiss

University of California-Berkeley

SAB member

Sonia Altieri 

EPA

Designated Federal Officer for

NACEPT

Thomas Armitage

EPA

Designated Federal Officer for

SAB

NATIONAL ADVISORY COUNCIL FOR ENVIRONMENTAL POLICY AND TECHNOLOGY ROE WORKGROUP

Acknowledgements 37
Office of Research and Development 

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$300 

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