United States

Environmental Protection

Agency

Office of Air Quality

Planning and Standards

Research Triangle Park, NC 27711

EPA-453/R-00-005

June 2000

Deposition of Air Pollutants

to the Great Waters

Third Report to Congress
Cover photo credits:

S.C. Delaney/EPA S.C. Delaney/EPA

S.C. Delaney/EPA

S.C. Delaney/EPA

S.C.

Delaney/EPA

Carole Y. Swinehart/

Michigan Sea Grant

Extension

ACKNOWLEDGMENTS

The report was prepared by the Office of Air Quality Planning and Standards of the U. S.

Environmental Protection Agency (EPA). The Project Leads were Gail Lacy and Dale Evarts. Completion

of this report could not have been possible without significant contributions from the wider community of

scientists and environmental experts involved with the programs and issues described in the report. In

particular, EPA would like to thank those persons who provided peer review of the draft report:

Mary Ann Allan Electric Power Research Institute, Palo Alto, California

Dr. Caroline Currin National Marine Fisheries Service, Beaufort, North Carolina

Elisabeth Galarneau Atmospheric Environment Service, Ontario, Canada

Dr. Louis Guillette Department of Zoology, University of Florida

Dr. Michael Murray National Wildlife Federation, Ann Arbor, Michigan

Dr. Hans Paerl Institute of Marine Sciences, University of North Carolina

Dr. Joseph Scudlark College of Marine Sciences, University of Delaware

In addition, EPA would like to acknowledge the substantive review and contributions provided by

Richard Artz and Margaret Kerchner of the Air Resources Lab of the National Oceanographic and

Atmospheric Administration, by Bob Larson of the National Atmospheric Deposition Program, and by

many staff of State, local and tribal agencies.

Within EPA, we would like to acknowledge the contributions of the Agency work group members

and others involved in the development of the report, including staff (too numerous to name) in the Offices

Air and Radiation, Water, Research and Development, Solid Waste and Emergency Response, Prevention,

Pesticides, and Toxic Substances, and General Counsel, as well as in the Great Lakes National Program

Office, the Chesapeake Bay Program Office, the Gulf of Mexico Program Office, EPA Regions IV and V,

and the National Estuary Program.
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page i

Great Waters Pollutants of Concern

Cadmium and cadmium compounds

Chlordane

DDT/DDE

Dieldrin

Hexachlorobenzene

"-Hexachlorocyclohexane

Lindane ((-hexachlorocyclohexane)

Lead and lead compounds

Mercury and mercury compounds

Polychlorinated biphenyls 

Polycyclic organic matter 

Tetrachlorodibenzo-p-dioxin (dioxins)

Tetrachlorodibenzofuran (furans)

Toxaphene

Nitrogen compounds

EXECUTIVE SUMMARY

With section 112(m) of the 1990 Clean Air Act (CAA), Congress directed the U.S.

Environmental Protection Agency (EPA), in cooperation with the National Oceanic and Atmospheric

Administration (NOAA), to identify and assess the extent of atmospheric deposition of air pollutants to

the Great Lakes, the Chesapeake Bay, Lake Champlain, and coastal waters, collectively known as the

Great Waters. Further, section 112(m) directed EPA to report its findings to Congress in periodic

reports. This is EPA’s third Report to Congress on the deposition of air pollutants to the Great Waters. 

The first report was published in May 1994, and the second report was published in June 1997.

The goals of the Third Great Waters Report to Congress are to discuss the current state of

knowledge regarding atmospheric deposition of pollutants to the Great Waters based on new research

and program activities undertaken since the Second Report to Congress and to describe any necessary

revisions to requirements, standards, and limitations under the CAA or other Federal laws. This report is

not intended to be a comprehensive summary of all relevant scientific research and activities. Instead, it

summarizes and highlights major trends and key findings, and builds on conclusions presented in the

First and Second Reports to Congress.

How does deposition of air pollutants affect public health and the

health of the Great Waters ecosystems?

A rapidly growing number of atmospheric

deposition monitoring and modeling studies confirm

that, along with runoff and discharges of pollution into

waterways, atmospheric deposition is a significant

pathway of pollutant inputs to the Great Waters. These

studies show that the contribution of atmospheric

deposition to overall pollutant loadings varies greatly by

pollutant and location. For example, studies show that

atmospheric deposition contributes from less than 5 to

100 percent of dioxins and furans entering the Great

Lakes, depending on the location of the monitoring site,

and from 2 to 38 percent of the nitrogen load to certain

coastal waters. Given this variability in contributions,

the improvement of the quality of the Great Waters

environments requires an understanding of all of the

sources of the pollutants into a waterbody, including

runoff from urban areas and farms, discharge from point sources, and seepage from contaminated

sediments, as well as atmospheric deposition.

Like the First and Second Reports to Congress, this report focuses on 15 pollutants of concern,

including certain pesticides, metal compounds, chlorinated organic compounds, and nitrogen compounds

(see sidebar). Some of these pollutants are single compounds while others represent categories of several

or even hundreds of individual compounds. They are emitted into the air by a wide range of sources,

including industries and other human activities, natural sources, and re-emissions of these pollutants from

soil and water. What is known about their emission rates, concentrations in the environment,

transformation processes, deposition rates and pathways, and health and environmental effects varies

widely. Nevertheless, recent research has added to our knowledge of the adverse human health and

ecological effects of these pollutants. At certain levels, these pollutants are associated with adverse
Executive Summary

Page ii Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

effects on many target organs in humans and animals, including the liver, kidney, nervous system,

endocrine system, reproductive organs, and immunological system. Research since the Second Report to

Congress provides additional evidence that some of the pollutants are likely “endocrine disruptors,”

meaning they may interfere with the action of hormones in wildlife and humans.

A number of regional and national assessments and monitoring programs described in this report

suggest that, while environmental conditions are improving in general, the current concentrations of

pollutants of concern continue to impair the ecological health of many Great Waters. For example, the

NOAA Estuarine Eutrophication Surveys indicate that approximately 89 percent of the Great Waters that

are coastal estuaries show some degree of adverse effects associated with amounts of nitrogen in excess

of natural levels. (Nitrogen is a natural component of these waterbodies, but excess amounts can also be

introduced through natural and human activities such as runoff from urban and agricultural areas and

atmospheric deposition.) Because of long-range atmospheric transport and certain chemical properties

(e.g., persistence, mobility, bioaccumulation, and bioconcentration), the pollutants of concern may

contribute to ecological impairment far from known emission sources and long after releases.

At current levels of contamination, pollutants of concern in the Great Waters pose potentially the

greatest health risks to individuals who consume fish from contaminated waters for subsistence or

cultural reasons, women of child-bearing age, the developing fetuses of pregnant women, and young

children who consume fish from contaminated waters. For mercury in particular, exposures do not

appear to pose a health risk to people consuming average amounts of fish, but sensitive sub-populations

(e.g., young children, and pregnant women and their developing fetuses) with higher than typical fish

consumption may be at risk. Also at risk are subsistence fish-eating populations who consume large

amounts of fish. The extent of risk for these groups depends on the amount of fish consumed and the

mercury concentrations present in the fish. 

What are the recent and anticipated trends in emission and

deposition of Great Waters pollutants of concern and their

concentrations in the Great Waters environment?

Where monitoring trends information exists, either nationally or locally, atmospheric deposition

of pollutants of concern to the Great Waters has declined or remained relatively constant in recent years,

as described in Chapter II. Specifically, deposition of lead, cadmium, polycyclic organic matter (POM) –

which includes a group of compounds known as polycyclic aromatic hydrocarbons (PAHs) –

polychlorinated biphenyls (PCBs), and some banned or restricted use pesticides is declining in the Great

Lakes. Other Great Waters have also shown decreasing trends of some of the pollutants of concern, such

as lead in Long Island Sound. Deposition of nitrogen in the U.S. has remained fairly constant. These

trends may reflect the results of emission reduction programs established under the CAA, pesticide bans,

as well as other local, tribal, State, Federal, and international pollution control efforts, many of which are

described in this report. There is considerable uncertainty in the trends estimates, however, because

limited monitoring capability, technological barriers, and variable collection and analysis methods make

it difficult to adequately characterize historical or current conditions. In addition, these estimates do not

address all Great Waters waterbodies for all pollutants of concern.

Emissions of mercury to the atmosphere come from human-made sources, natural emissions, and

re-emission from biologic and geologic processes. Emissions of mercury have been on a downward trend

since 1990, due chiefly to the phase-out of mercury in many products. Nevertheless, monitoring suggests

that atmospheric deposition is a significant contributor of mercury to the Great Waters. At EPA’s current

reference dose for mercury, levels in some lakes and streams remain sufficiently high to pose adverse
Executive Summary

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page iii

human health and ecological risks and to result in fish consumption advisories for mercury in many Great

Waters.

Lead air emissions, ambient air concentrations, and deposition levels in the Great Lakes region

have also decreased in recent years. Cadmium emissions in the Great Lakes region, on the other hand,

increased in the 1980s and have not shown a trend since then, while cadmium deposition in the Great

Lakes region is believed to have decreased in recent years. In the Chesapeake Bay, trends in atmospheric

deposition of lead and cadmium are difficult to discern with current information, but total inputs of both

lead and cadmium in some eastern parts of the bay have increased in recent years due to the increase in

population and industrial activities. In some areas of the Chesapeake Bay, levels of these metals may be

high enough in sediments to cause adverse ecological effects. 

Air emissions of dioxins, furans, and POM (including PAHs) in the U.S. are from both natural

and human-made combustion and incineration processes. Emissions have declined for dioxins and

furans, while trends for POM are not known. A large degree of variation has been observed in deposition

levels of dioxins and furans over time within and between the Great Lakes. Deposition levels of these

compounds are related to the pattern of industrialization and population density. In many instances, long

term monitoring indicates that concentrations of dioxins and furans in biota in the Great Waters have

declined over time. Analytical results indicated that levels in aquatic species are declining steadily and

in several Great Waters, no dioxin was found in fish samples taken between 1987 and 1994. 

Although CAA programs have had a major impact on nitrogen oxide (NOx) emissions, the

emission reductions have been balanced approximately equally with emission increases attributable to

economic growth, resulting in a relatively flat trend since 1980. Deposition monitoring data suggest that

the deposition rates of inorganic nitrogen (e.g., NOx, ammonia) to many of the Great Waters watersheds

have also been relatively constant for the past two decades, though some increases have been noted

downwind of areas where population or livestock operations are growing. The EPA expects that

additional NOx controls to be implemented under the CAA will slightly outpace emission increases

associated with economic growth, resulting in a net decreasing trend in NOx emissions through 2005. 

Emissions are expected to remain steady at that level until 2010. Research is ongoing into the lesser

known, but apparently important, forms of nitrogen deposition (e.g., dry deposition, organic nitrogen). 

Current and anticipated nitrogen deposition rates are significantly greater than natural rates, and

combined with nitrogen inputs from runoff from farms and cities, have the potential to overwhelm the

capacities of surface waters to assimilate the additional nitrogen.

Manufacture of PCBs in the U.S. no longer occurs; however, releases into the environment

continue to occur because of PCBs in electrical transformers and capacitors that are still in use, releases

from soils and sediments contaminated with PCBs, and releases during some combustion processes. The

number and magnitude of PCB sources in the U.S. has decreased 20-fold in the past 20 years. 

Furthermore, deposition of PCBs in the Great Lakes has decreased and a net loss of PCBs has been

observed in the Chesapeake Bay. Overall, PCB concentrations in the environment appear to have

declined but are still present and continue to result in the need for fish consumption advisories in many

Great Waters.

Based on recent academic research on atmospheric pollutant concentrations in the Great Lakes

region, DDT and DDE, followed by dieldrin and chlordane, are estimated to fall below current detection

limits in the atmosphere between 2010 and 2020. Hexachlorocyclohexane and hexachlorobenzene are

projected to be eliminated in the atmosphere by 2030 and 2060, respectively. These estimates assume

current rates of long-range transport of these pollutants into the region and do not mean that

concentrations would be eliminated in deposited media (water and sediments) by these dates. However,
Executive Summary

Page iv Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

these estimates indicate that reduction strategies in the Great Lakes, along with the original bans and

restrictions on the use of these substances, are having the intended effect.

What actions are EPA and others taking to address atmospheric

deposition?

Chapter III of this report describes more than 60 programs under way from the local to

international levels that directly or indirectly contribute to reducing atmospheric deposition of pollution

to the Great Waters or to understanding its effects. Although EPA leads or supports many of these

programs, which often use multimedia and cross-program approaches to control pollution, other Federal

agencies, State and tribal organizations, industry groups, and Canada have also initiated and implemented

many important activities. Examples of EPA’s cross-program and multimedia approaches include the

pulp and paper industry “cluster rule” that for the first time integrates, coordinates, and streamlines

applicable requirements of the Clean Water Act and the CAA. The EPA’s air and water programs are

also working together to address the contribution of air deposition into water quality protection under

total maximum daily load (TMDL) determinations. This also includes coordinated activities such as the

Persistent Bioaccumulative Toxics Initiative, Clean Water Action Plan, and Contaminated Sediment

Management Strategy. Several State organizations have successfully worked with industry and

municipalities to develop pollution prevention programs and programs to collect banned and restricted

use pesticides. Tribes are working to reduce exposure of indigenous populations to pollutants of concern

through a variety of efforts, and industry has initiated efforts to reduce the use of pollutants of concern in

products and processes. Canada has implemented a variety of programs, some of which are joint efforts

with the U.S., like the Binational Toxics Strategy which seeks to eliminate pollutants of concern from the

Great Lakes environment. 

These coordinated Agencywide efforts demonstrate EPA’s commitment to implement the

strategic directions discussed in the First and Second Reports to Congress and in the section 112(m)(6)

adequacy determination, and to pursue all authorities available for addressing atmospheric deposition and

Great Waters pollutants of concern. In addition, developing and implementing these and other programs

and initiatives described in this report have not required revisions to requirements, standards, and

limitations in accordance with the CAA and other Federal laws which provide protection of human health

and the environment from atmospheric deposition to the Great Waters.

What are EPA’s findings and conclusions from this Third Report

to Congress?

The new scientific and programmatic information presented in this report supports and builds on

the three broad conclusions presented in the First and Second Reports to Congress.

• Atmospheric deposition from human activities can be a significant contributor of toxic chemicals

and nitrogen compounds to the Great Waters. The relative importance of atmospheric loading

for a particular chemical in a given waterbody depends on many factors, including characteristics

of the waterbody, properties of the chemical, and the kind and amount of atmospheric or water

discharges. 

C A plausible link exists between emissions into the air of Great Waters toxic pollutants of

concern, the atmospheric deposition of these pollutants (and their transformation products), and

the concentrations of these pollutants found in water, sediments and biota, especially fish and

shellfish. For mercury, fate and transport modeling and exposure assessments predict that the
Executive Summary

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page v

anthropogenic contribution to the total amount of methylmercury in fish is, in part, the result of

anthropogenic mercury releases from industrial and combustion sources increasing mercury body

burdens (i.e., concentrations) in fish. Furthermore, the consumption of fish is the dominant

pathway of exposure to methylmercury for fish-consuming humans and wildlife. However, what

is known about each stage of this process varies with each pollutant (for instance, the chemical

species of the emissions and its transformation in the atmosphere).

C Airborne emissions from local as well as distant sources, both within and outside the U.S.,

contribute pollutant loadings to waters through atmospheric deposition. Determining the relative

roles of particular sources -- local, regional, national, and possibly global, as well as

anthropogenic, natural, and re-emission of pollutants -- contributing to specific waterbodies is

complex, requiring careful monitoring, atmospheric modeling, and other analytical techniques.

Actions taken by EPA and others to control sources of Great Waters pollutants of concern appear

to have positively affected trends in pollutant concentrations measured in air, water, sediment, and biota. 

Overall deposition rates of pollutants of concern have declined slightly or remained constant. Several

pollutants of concern continue to enter the Great Waters primarily through atmospheric deposition. In

addition, long-range transport of pollutants of concern from other U.S. regions or other countries is

estimated to contribute significantly to atmospheric loadings to the Great Waters. For example, the

global reservoir of mercury (which includes mercury from both U.S. and foreign sources) is estimated to

contribute about 40 percent of the total mercury deposition to U.S. lands and waters.

Concentrations of some pollutants of concern in the water, sediment, and biota of the Great

Waters declined in recent years, whereas others were constant or variable. Concentrations of most

pollutants of concern still pose potential adverse ecological and human health effects. For example,

approximately 5 percent of the Nation’s coastal and inland watersheds include “areas of probable

concern,” meaning a watershed that is associated with a certain number of monitoring sites with sediment

contamination at levels likely to cause adverse effects. Water quality data also indicate that water quality

standards in place for drinking water supplies in the Great Waters are not being exceeded for the

pollutants of concern, but that surface water quality guidance and criteria are being exceeded for some of

the Great Waters. In addition, nationally, fish consumption advisories were in place for 39 of 56 Great

Waters waterbodies as of 1997. 

Based on current trends, EPA expects atmospheric deposition to remain a significant source of

several pollutants of concern to the Great Waters for the foreseeable future. In addition, because of the

ability of these pollutants to persist and bioaccumulate, they are expected to remain in the water,

sediments and biota for much longer. 

Implementation of existing EPA regulations is expected to further reduce emissions of mercury,

NOx, POMs, dioxins and furans, cadmium, and hexachlorobenzene. The EPA continues to implement

programs under CAA authorities and expects that pollutant emissions will be further controlled by

several rules scheduled to take effect in coming years. As a result, atmospheric deposition and loadings

of these pollutants may be significantly reduced. In addition, actions taken to voluntarily reduce

chemical use, implement pollution prevention initiatives, advance technology (e.g., alternative fuel

vehicles), and implement pollution control laws issued by States and other nations will further reduce

pollutant loadings to the Great Waters.
Executive Summary

Page vi Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

What future directions will EPA follow to implement section

112(m)?

The EPA developed six key recommendations that will assist in meeting the objectives and

requirements of the CAA related to the Great Waters program.

• The EPA will continue to support the maintenance and expansion of efforts to monitor Great

Waters pollutants of concern in order to evaluate the relative contributions of local, regional, and

long-range transport to deposition in the U.S., as well as natural versus human-made sources.

• The EPA will continue to develop and implement regulations and pollution prevention programs

regionally and nationally, including multimedia programs, in order to reduce the impact of

sources of Great Waters pollutants of concern within the U.S.

• For Great Waters pollutants emitted by sources outside the U.S., EPA will work within

international frameworks to reduce sources of these pollutants.

• The EPA will support model development and research that establish and clarify the linkages

from emissions to atmospheric deposition to waterbody loadings to adverse public health and the

environmental effects of Great Waters pollutants of concern in order to enable effective risk

management decisions.

• The EPA will encourage and support the establishment of common baselines and measures of

progress in order to better assess trends and health of Great Waters and other waterbodies

affected by atmospheric deposition.

• The EPA will work to increase public awareness of risks of exposure to Great Waters pollutants.

These key recommendations build on the strategic themes identified in the First and Second

Reports to Congress: (1) continued implementation of the CAA to directly control emissions of Great

Waters pollutants of concern; (2) use of an integrated multimedia approach throughout the Agency,

including coordination of clean air programs with programs available under other Federal laws (e.g.,

Clean Water Act); and, (3) continued support of research activities that address the goals of the Great

Waters program.

In support of the first strategic theme, EPA will develop or assess the need for new rules and

programs under the CAA, including maximum achievable control technology (MACT) standards, section

112(c)(6) standards, as well as standards that could stem from the residual risk program, the utility air

toxics determination, and the integrated urban air toxics strategy. As appropriate, EPA will consider the

impacts of atmospheric deposition in developing standards under these authorities. In addition, EPA will

ensure the timely implementation of NOx control programs already in place and will encourage

innovative, nonregulatory approaches to reducing NOx emissions and other sources of atmospheric

nitrogen. 

This report describes a number of multimedia and cross-program initiatives (e.g., Clean Water

Action Plan, Persistent Bioaccumulative Toxics Initiative) that are in line with EPA’s second strategic

theme for the Great Waters program. Some of these initiatives, such as the pulp and paper cluster rule,

will produce tangible environmental benefits within the near future. Other initiatives, such as

development of multimedia models in support of TMDL determinations and completion of the
Executive Summary

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page vii

Contaminated Sediment Non-point Source Inventory, will provide tools and data resources that will help

EPA target future pollution control activities.

There has been substantial progress in research activities relevant to the Great Waters program

since the Second Report to Congress. However, important information gaps remain, and there are critical

limitations to current atmospheric monitoring and modeling capabilities. Consistent with the third

strategic theme, therefore, EPA will initiate and continue to support scientific research to fill these

critical gaps, including the following activities:

• Support research to examine and quantify the ecological effects of atmospheric deposition and to

better quantify the water quality benefits of air pollution controls;

• Expand the geographic coverage and consistency of waterbody monitoring to enable more

accurate characterizations of the extent of contamination and ecosystem effects due to

atmospheric deposition; 

• Encourage and support interagency coordination to better quantify the indirect loadings of

atmospheric deposition to the Great Waters through the development of tools that can quantify

watershed transport of pollutants of concern;

• Continue to support the development of modeling tools which address the transport and fate of

pollutants in ecosystems and characterize risk, including research to clarify mechanisms of

mercury methylation so as to better predict and manage ecosystems at risk;

C Develop reliable approaches for quantifying and monitoring nitrogen dry deposition and wet

organic nitrogen deposition;

• Support joint work with States and industry to fill gaps in emissions information for MACT

source categories and further refine emissions measurement methods, inventories, and modeling

for Great Waters pollutants of concern;

C Support research on viable prevention and controls for sources of pollutants of concern; 

• Encourage and support greater coordination and expansion of monitoring networks to assess

deposition of pollutants to coastal waters, to assess the contribution of long-range transport to

deposition in the U.S., and to evaluate the impact of agricultural and urban sources;

• Develop standard methods to monitor pollutants of concern to enable the comparison of data and

trends analyses;

• Support international efforts to quantify the transboundary contributions of pollutants of concern

and to share technology, information, and expertise with other countries on reducing releases to

the environment and on cost-effective alternatives to their use;

• Working closely with other EPA and inter-governmental efforts to address, in particular,

persistent bioaccumulative toxic pollutants, and to identify and evaluate additional pollutants

which may be of concern to the Great Waters;

• Continue research to identify additional endocrine disrupting chemicals and their associated

effects; and,
Executive Summary

Page viii Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

• Continue coordination and support of efforts to improve the consistency of fish consumption

advisories and the awareness and understanding of advisories among populations most at risk to

exposure to the Great Waters pollutants of concern.

The EPA is committed to continuing to address air deposition of pollutants into the Nation’s

waters as a priority matter. To that end, and to assure continued coordination of the many related tasks

involved and outlined in this report, EPA will develop a detailed biennial work plan for implementation

actions beginning this year and updated every two years. As EPA develops and implements plans,

programs and initiatives with NOAA and its other Federal, State, tribal, industry and community

partners, we expect to make significant, measurable progress toward our goal of assuring the protection

of human health and the environment from adverse effects attributable to atmospheric deposition of

pollution to the Great Waters. 
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page ix

TABLE OF CONTENTS

PAGE

ACKNOWLEDGMENTS

EXECUTIVE SUMMARY ............................................................ i

LIST OF TABLES ................................................................. xii

LIST OF FIGURES ................................................................ xiv

LIST OF ABBREVIATIONS AND ACRONYMS ....................................... xv

I. INTRODUCTION AND BACKGROUND ....................................... I-1

A. Overview of the Great Waters Program ........................................ I-3

Definition of Great Waters .............................................. I-3

Program Participants and Organizations .................................... I-3

Government Goals Supported by the Great Waters Program and Its Partners ....... I-6

B. Pollutants of Concern ...................................................... I-7

C. Goals of the Third Report to Congress ........................................ I-13

II. ENVIRONMENTAL PROGRESS ............................................ II-1

Pollutant-Specific Changes .................................................... II-3

Mercury and Compounds ............................................... II-4

Other Metals (Lead and Cadmium) ...................................... II-19

Combustion Emissions ............................................... II-31

Nitrogen and Compounds ............................................. II-40

Banned and Restricted Use Substances ................................... II-58

Cross-Pollutant Trends ...................................................... II-67

Fish Consumption Advisories .......................................... II-68

Water Quality Assessments ............................................ II-69

NOAA’s National Status and Trends Program ............................. II-70

National Sediment Quality Survey ...................................... II-73

Chesapeake Bay Program ............................................. II-73

Lake Champlain Sediment Toxics Assessment Program ..................... II-75

San Francisco Estuary Regional Monitoring Program for 

Trace Substances ............................................. II-76

III. MAJOR PROGRAMS AND ACTIVITIES ..................................... III-1

A. National Programs and Activities ............................................ III-3

Multimedia Activities ................................................. III-4

Hazardous Air Pollutant (HAP) Controls ................................. III-11

Stationary Source Controls Addressing NOx............................... III-17

Mobile Source Program Activities ...................................... III-29

Ozone and PM NAAQS and Proposed Regional Haze Rule ................... III-30

Other National Programs .............................................. III-30

B. Regional and Waterbody-Specific Programs .................................. III-34

Great Lakes Program ................................................. III-35

Lake Champlain Basin Program ........................................ III-37

Chesapeake Bay Program ............................................. III-38

Gulf of Mexico Program .............................................. III-41
Table of Contents

Page x Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

PAGE

National Estuary Program ............................................. III-42

NOAA Activities .................................................... III-48

Ozone Transport Commission (OTC) .................................... III-49

C. State, Local, and Tribal Activities .......................................... III-51

State and Local Activities ............................................. III-51

Tribal Activities ..................................................... III-60

D. Industry Activities ....................................................... III-63

Chlor-alkali Industry Mercury Reduction Goal ............................. III-63

Voluntary Mercury Agreement with Northwest Indiana Steel Mills ............ III-64

American Hospital Association MOU .................................... III-64

Electric Power Research Institute Studies ................................. III-65

E. Work with Other Countries ................................................ III-66

Canada-U.S. Binational Toxics Strategy .................................. III-66

International Joint Commission ......................................... III-69

United Nations Economic Commission for Europe LRTAP Protocols

on Heavy Metals and POPs ..................................... III-70

United Nations Environment Program Global POPs Initiative ................. III-71

NAFTA Commission on Environmental Cooperation Sound Management

 of Chemicals Program ............................................ III-71

U.S.-Canada Air Quality Agreement ..................................... III-72

IV. SCIENCE AND TOOLS .................................................... IV-1

What Major Advancements Have Occurred Since the Second Report? .................. IV-2

Emission Inventories .................................................. IV-2

Ambient Air and Deposition Monitoring Networks .......................... IV-4

Other Environmental Monitoring Networks and Databases .................... IV-8

Environmental Transport and Fate ...................................... IV-11

Measuring and Monitoring Techniques ................................... IV-20

Exposure and Effects Research ......................................... IV-21

V. NEXT STEPS FOR THE GREAT WATERS PROGRAM ........................ V-1

A. Pollutant Sources ........................................................ V-4

Findings and Conclusions .............................................. V-4

Recommendations for Continued and Further Action ......................... V-5

B. Contribution of Atmospheric Deposition to Pollutant Loadings in the Great Waters .... V-8

Findings and Conclusions .............................................. V-8

Recommendations for Continued and Further Action ........................ V-10

C. Environmental and Public Health Effects ..................................... V-11

Finding and Conclusions .............................................. V-11

Recommendations for Continued and Further Action ........................ V-12

D. Exceedances of Water Quality or Drinking Water Standards ..................... V-14

Finding and Conclusions .............................................. V-14

Recommendations for Continued and Further Action ........................ V-14

E. Summary and Key Recommendations ........................................ V-16

REFERENCES

INDEX OF WATERBODIES
Table of Contents

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page xi

APPENDIX A: Major Sources of Information – Publications and Internet Sites

APPENDIX B: Detailed Breakdown of Air Emissions Inventory by Pollutant for Source

Categories Emitting Less than One Percent of Total U.S. Emissions

APPENDIX C: Fish Consumption Advisories Issued for the Great Waters

APPENDIX D: Names of Numbered Sites from Figure II-17: Locations of Watersheds

Designated as Areas of Probable Concern
Table of Contents

Page xii Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page xiii

LIST OF TABLES

CHAPTER I PAGE

Table I-1: Uses/Sources and U.S. Regulatory Status of Great Waters Pollutants of 

Concern .......................................................... I-9

Table I-2: EPA Multimedia and Cross-program Management of the Great Waters

Pollutants of Concern .............................................. I-10

Table I-3: Great Waters Pollutants of Concern Addressed by Selected Waterbody, Regional, 

and International Activities .......................................... I-12

CHAPTER II

Table II-1: National Anthropogenic Mercury Air Emissions ............................ II-7

Table II-2: Preliminary Estimates of Total Atmospheric Mercury Deposition to 

Lake Michigan ...................................................... II-13

Table II-3: Mercury Sources Identified in Mass Balance Studies (By Percent Contribution) . . II-14

Table II-4: National Anthropogenic Lead Air Emissions .............................. II-23

Table II-5: National Anthropogenic Cadmium Air Emissions .......................... II-25

Table II-6: Trace Metals Inputs to the Chesapeake Bay ............................... II-26

Table II-7: Direct Atmospheric Deposition of Lead and Cadmium to Massachusetts 

Bay ............................................................ II-27

Table II-8: Temporal Changes in Metal Concentrations in Chesapeake Bay 

Tributaries Based on Sediment Cores ................................. II-29

Table II-9: Cadmium and Lead in Sediments of the Chesapeake Bay Mainstem ............ II-30

Table II-10: Lead and Cadmium in Horseshoe Crab Eggs from Delaware Bay .............. II-30

Table II-11: National Anthropogenic Dioxin and Furan TEQ Air Emissions ................ II-32

Table II-12: Current Rates of Dioxins and Furans Accumulation in Great Lakes 

Sediments ...................................................... II-33

Table II-13: Modeled Air Deposition, Depositional Flux, and Waterborne Inputs of Dioxins 

and Furans to the Great Lakes ....................................... II-33

Table II-14: National Anthropogenic 16-PAH Air Emissions ............................ II-35

Table II-15: Sum of Wet and Dry Deposition of PAHs onto Massachusetts Bay ............ II-38

Table II-16: Estimates of PAH Inputs to the Chesapeake Bay ........................... II-39

Table II-17: Annual PAH Inputs to and Losses from the Chesapeake Bay .................. II-39

Table II-18: Common Forms of Atmospheric Nitrogen ................................ II-42

Table II-19: Transfer of Atmospheric Deposition Nitrogen (ADN) from Various Watershed 

Areas .......................................................... II-52

Table II-20: Transfer of Atmospheric Deposition Nitrogen (ADN) from Watersheds to 

Several Bays and Estuaries ......................................... II-52

Table II-21: Atmospheric Nitrogen Loads Relative to Total Nitrogen Loads in Selected 

Great Waters .................................................... II-53

Table II-22: National Anthropogenic PCB Air Emissions .............................. II-59

Table II-23: IADN Loading Estimates of PCBs (wet and dry) for the Great Lakes ........... II-60

Table II-24: IADN Loading Estimates of DDT (wet and dry) to the Great Lakes ............ II-64

Table II-25: Current and Maximum Rates of Toxaphene Accumulation in Great Lakes 

Sediments ...................................................... II-66

Table II-26: Modeled Air Deposition, Depositional Flux, and Waterborne Inputs of HCB to 

the Great Lakes .................................................. II-67

Table II-27: Trends of Pollutant Concentrations in Mussel Watch Project (1986-1996) ....... II-72
List of Tables

Page xiv Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

PAGE

Table II-28: Percentages of 1996 Samples that Exceeded Guidelines in the San

Francisco Estuary ................................................ II-76

CHAPTER III

Table III-1: Source Categories With Effective Compliance Dates and Anticipated Reductions

of HAP Emissions ................................................ III-11

Table III-2: Proposed and Final Rules Affecting Pollutants of Concern ................... III-13

Table III-3: Emission Reductions Expected from Control Equipment Used to Retrofit A 

Typical Existing MWC Plant ....................................... III-17

Table III-4: Emission Reductions Expected from Existing HMIWI ....................... III-18

Table III-5: Emission Reductions Expected at New HMIWI after 5 Years of NSPS 

Implementation .................................................. III-19

Table III-6: Recent Regulations Affecting Stationary Source NOx Emissions ............... III-20

Table III-7: Pounds of Pesticides Collected through Clean Sweep Programs 

Nationwide ..................................................... III-57

Table III-8: U.S. BNS Challenge Goals and Activities for Level I Substances .............. III-68
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page xv

LIST OF FIGURES

CHAPTER I PAGE

Figure I-1: Pollutant Transport Pathways to Waterbodies ................................ I-1

Figure I-2: Locations of the Great Waters ............................................ I-3

CHAPTER II

Figure II-1: Atmospheric Release, Transport, and Deposition Processes .................... II-2

Figure II-2: Monitoring Sites of the Mercury Deposition Network – 1999 ................. II-10

Figure II-3: 1993 Lead Emissions in the Great Lakes Region ........................... II-22

Figure II-4: 1982 Lead Emissions in the Great Lakes Region ........................... II-22

Figure II-5: 1993 Cadmium Sources in the Great Lakes Region ......................... II-23

Figure II-6: Chesapeake Bay Tidal and Non-tidal Waters .............................. II-26

Figure II-7: IADN Loading Estimates of B[a]P to the Great Lakes ....................... II-37

Figure II-8: National NOx Emission Trends, 1985-1996 ............................... II-45

Figure II-9: 1996 NOx Emissions by State .......................................... II-46

Figure II-10: 1996 National Anthropogenic NOx Emissions by Principle Source 

Category ....................................................... II-45

Figure II-11: Estimated Nitrogen Emissions to Air by Principle Source Category in North 

Carolina - Anthropogenic and Biogenic ............................... II-47

Figure II-12: Estimated Inorganic Nitrogen Wet Deposition, 1997 ........................ II-48

Figure II-13: Nitrogen Wet Deposition in the Chesapeake Bay Watershed .................. II-50

Figure II-14: Nitrogen Wet Deposition in the Great Lakes Watersheds ..................... II-50

Figure II-15: Nitrogen Wet Deposition in the Lake Champlain Watershed .................. II-50

Figure II-16: Expected Year that Great Waters Pesticides will be Below Current Detection 

Limits in the Great Lakes Atmosphere ................................ II-64

Figure II-17: Locations of Areas of Probable Concern Within Watersheds .................. II-74

CHAPTER III

Figure III-1: Projected National NOx Emission Trends, 1996-2010 ....................... III-19

Figure III-2: The 43 Areas of Concern in the Great Lakes Basin ......................... III-36

CHAPTER IV

Figure IV-1: Monitoring Sites of Ambient Air and Deposition Monitoring Networks Measuring 

Pollutants of Concern .............................................. IV-5

Figure IV-2: Revised Principal Airshed for the Chesapeake Bay ......................... IV-15
List of Figures

Page xvi Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page xvii

ABBREVIATIONS AND ACRONYMS

ADN Atmospheric deposition nitrogen

AEOLOS Atmospheric Exchange Over Lakes and Ocean Surfaces

AIEO American Indian Environmental Office

AILESP American Indian Lands Environmental Support Project

AIRMoN Atmospheric Integrated Research Monitoring Program

AOC Areas of concern

APC Areas of probable concern

AQC Air Quality Committee 

ARL Air Resources Laboratory

ATSDR Agency for Toxic Substances and Disease Registry

BACT Best available control technology

BASMAA Bay Area Stormwater Management Agencies Association

BNS Binational Toxics Strategy

BRACE Bay Regional Atmospheric Chemistry Experiment

CAA Clean Air A ct

CASTNet Clean Air Status and Trends Network

CBADS Chesapeake Bay Atmospheric Deposition Study

CBEP Community-Based Environmental Program

CBP Chesapeake Bay Program

CBPO Chesapeake Bay Program Office

CEC Commission on Environmental Cooperation

CENR Committee on Environment and Natural Resources 

CHPAC Children’s Health Protection Advisory Committee

CMAQ Community multi-scale air quality

CTDEP Connecticut Department of Environmental Protection

CVAFS Cold vapor atomic fluorescence spectrometry

CWA Clean Water Act

CZM Coastal zone management

DC District of Columbia

DDD 1,1'-(2,2-dichloroethylidene)bis(4-chlorobenzene)

DDE 1,1'-(dichloroethenylidene)bis(4-chlorobenzene)

DDT 1,1'-(2,2,2-trichloroethylidene)bis(4-chlorobenzene)

DIN/SRP Dissolved inorganic nitrogen to soluble reactive phosphorus

DNREC Department of Natural Resources and Environmental Conservation

EAGLE Effects on Aboriginals from the Great Lakes Environment 

EDSTAC Endocrine Disruptor Screening and Testing Advisory Committee

EEGLE Episodic Events/Great Lakes Experiment

EGU Electric generation units

EMAP Environmental Monitoring and Assessment Program

EPCHC Environmental Protection Committee of Hillsborough County

EOM Extractable organic matter

EPA Environmental Protection Agency

EPRI Electric Power Research Institute

FAMS Florida Atmospheric Mercury Study

FCP Fish Contamination Program

FDEP Florida Department of Environmental Protection

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FIP Federal implementation plan

FR Federal Register
Abbreviations and Acronyms

Page xviii Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

g Gram

GIS Geographic Information System

GLNPO Great Lakes National Program Office

GLWQA Great Lakes Water Quality Agreement

GMPO Gulf of Mexico Program Office

GPRA Government Performance and Results Act

HAP Hazardous air pollutant

HCB Hexachlorobenzene

HCH Hexachlorocyclohexane

HMIWI Hazardous/medical/infectious waste incinerators

HNO3 Nitric acid

HYSPLIT Hybrid single particle Lagrangian integrated trajectory

IADN Integrated Atmospheric Deposition Network

IAQAB International Air Quality Advisory Board

IBI Index of Biotic Integrity

IDEM Indiana Department of Environmental Management

IJC International Joint Commission

INC International Negotiating Committee

kg Kilogram

LaMP Great Lakes Lakewide Management Plans

LAER Lowest achievable emission rate

LCBP Lake Champlain Basin Program

LISS Long Island Sound Study

LMMBS Lake Michigan Mass Balance Study

LRTAP Europe Long-Range Transboundary Air Pollution

MACT Maximum achievable control technology

MCL Maximum contaminant level

MCM Mercury cycling model

MDEQ Michigan Department of Environmental Quality

MDN Mercury Deposition Network

MOU Memorandum of Understanding

MPCA Minnesota Pollution Control Agency

MTRL Maximum tissue residue level

MWC Municipal waste combustors

N Nitrogen

NAAEC North American Agreement on Environmental Cooperation

NAAQS National ambient air quality standard

NADP National Atmospheric Deposition Program

NADP-MDN National Atmospheric Deposition Program - Mercury Deposition Network

NADP-NTN National Atmospheric Deposition Program - National Trends Network

NAFTA North American Free Trade Agreement

NCSU North Carolina State University

NDAMN National Dioxin Air Monitoring Network

NEP National Estuary Program

NERRS National Estuarine Research Reserve System 

NESCAUM Northeast States and Eastern Canadian Provinces Mercury Study

NH3 Ammonia

NH4

+ Ammonium

NHx Reduced nitrogen compounds (e.g., ammonia, ammonium)

NLFWA National Listing of Fish and Wildlife Advisories
Abbreviations and Acronyms

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page xix

NLEV National low emission vehicle

NO Nitric oxide

NO2 Nitric dioxide

NO3 Aerosol nitrate

NOAA National Oceanic and Atmospheric Administration

NOEL No observed effects level

NOx Oxides of nitrogen

NS&T National Status and Trends

NSI National Sediment Inventory

NSPS New source performance standards

NSQS National Sediment Quality Survey

NTI National Toxics Inventory

NORBIC North Business-Industrial Council

OAP Office of Atmospheric Programs

OAQPS Office of Air Quality Planning and Standards

OAR Office of Radiation

OC Organochlorine chemical

OCHP Office of Children’s Health Protection

OMS Office of Mobile Sources

OPPTS Office of Pollution Prevention and Toxics

ORD Office of Research and Development

OTAG Ozone Transport Assessment Group

OTAQ Office of Transportation and Air Quality

OTC Ozone Transport Commission

OTR Ozone Transport Region

OW Office of Water

PAH Polycyclic aromatic hydrocarbon

PBT Persistent bioaccumulative toxic

PCB Polychlorinated biphenyl

PCDD Polychlorinated dibenzo-p-dioxin

PCDF Polychlorinated dibenzofuran

PEL Probable effects level

PM Particulate matter

POM Polycyclic organic matter

POP Persistent organic pollutant

RACT Reasonably available control technology

RADM Regional Atmospheric Deposition Model

RAP Regional action plan

RELMAP Regional Lagrangian Model of Air Pollution

R-EMAP Regional Environmental Monitoring and Assessment Program

REMSAD Regulatory Modeling System for Aerosols and Deposition

SAB Science Advisory Board

SAV Submerged aquatic vegetation

SFEI San Francisco Estuary Institute

SFEP San Francisco Estuary Project

SIP State implementation plan

SMOC Sound management of chemicals

SoFAMMS South Florida Atmospheric Mercury Monitoring Study

SVOC Semi-volatile organic compound

SWFWMD Southwest Florida Water Management District
Abbreviations and Acronyms

Page xx Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

SWMP System-Wide Monitoring Program

TBNEP Tampa Bay National Estuary Program

TEQ Toxic equivalent quantity

TLRI Toxics Loading and Release Inventory

TMDL Total maximum daily load

tpy Tons per year

TRANSCO Transfer coefficient

TRI Toxic Release Inventory

TRIM Total Risk Integrated Methodology

TSCA Toxic Substances Control Act

UNC-CH University of North Carolina at Chapel Hill

UN-ECE United Nations Economic Commission for Europe

UNEP United Nations Environment Program

US United States

USGS U.S. Geological Survey

VOC Volatile organic compound

WLSSD Western Lake Superior Sanitary District

WMNP Waste Minimization National Plan

WMPT Waste Minimization Prioritization Tool

WQB Water Quality Board

WRDA Water Resources Development Act

yr Year
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-1

CHAPTER I

INTRODUCTION AND BACKGROUND

Although water quality has improved in past years, ongoing research indicates that many of the

Nation’s waterbodies, including the Great Waters, are impacted by degraded water quality and associated

adverse health and ecological effects. These impacts are due, in part, to inputs of pollutants from a

variety of sources and through multiple pathways, including atmospheric deposition (Figure I-1). The

role of air pollution as an important contributor to water pollution has long been recognized and, in

recent years, has been the subject of growing scientific study and concern to regulatory agencies. Section

112 of the CAA provides the statutory basis for hazardous air pollutant (HAP) programs directed by

EPA. In response to mounting evidence that air pollution contributes to water pollution, Congress

included section 112(m), Atmospheric Deposition to Great Lakes and Coastal Waters, in the 1990

Amendments to the CAA to establish research, reporting, and potential regulatory requirements related to

atmospheric deposition of HAPs to the “Great Waters.”

Figure I-1

Pollutant Transport Pathways to Waterbodies

This report fulfills the requirements in section 112(m)(5), which direct EPA, in cooperation with

NOAA, to periodically submit a Report to Congress including information on pollutant sources and

emissions, loadings, effects, and exceedances of guidelines in the Great Waters. The biennial report is

required under section 112(m) of the CAA to cover the following: 

1. The contribution of atmospheric deposition to pollution loadings in the Great Waters; 

2. The environmental and public health effects of any pollution attributable to atmospheric

deposition to these waterbodies; 

3. The sources of any pollution attributable to atmospheric deposition to these waterbodies;
Chapter I

Introduction and Background

Page I-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

4. Whether pollution loadings in these waterbodies cause or contribute to exceedances of drinking

water or water quality standards or, with respect to the Great Lakes, exceedances of the specific

objectives of the Great Lakes Water Quality Agreement; and,

5. Descriptions of any revisions of the requirements, standards, and limitations of relevant CAA

and Federal laws to ensure protection of human health and the environment.

The First and Second Great Waters Reports to Congress on atmospheric deposition to the Great

Waters were published in May 1994 (U.S. EPA 1994) and June 1997 (U.S. EPA 1997b). The first two

reports presented the programmatic background and covered the scientific issues that are addressed by

the Great Waters program. The Third Great Waters Report to Congress provides an update to the

information presented in previous reports and specifically highlights progress made since the Second

Report to Congress, including changes in pollutant emissions, deposition, and effects, as well as recent

advancements in the scientific understanding of relevant issues. In addition, the report discusses recent

activities and accomplishments of the many different initiatives that help protect the Great Waters from

pollutants deposited from the atmosphere. 
Chapter I

Introduction and Background

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-3

I.A OVERVIEW OF THE GREAT WATERS PROGRAM

DEFINITION OF GREAT WATERS

The waterbodies collectively referred to as the “Great Waters” in this report are the Great Lakes,

Lake Champlain, Chesapeake Bay, and specific coastal waters defined in the statute as coastal waters

designated through the National Estuary Program (NEP) and the National Estuarine Research Reserve

System (NERRS). Figure I-2 displays the locations of these waterbodies. Examples of some of the

coastal waters designated as Great Waters include Tampa Bay, Santa Monica Bay, San Francisco Bay,

Puget Sound, Galveston Bay, Casco Bay, the New York Bight, and Albemarle-Pamlico Sounds.

Figure I-2

Locations of the Great Waters

PROGRAM PARTICIPANTS AND ORGANIZATIONS

The EPA’s Great Waters program was established to implement the provisions of section 112(m)

of the CAA. In partnership with NOAA, this program is charged with examining the sources and impacts

of air pollutant deposition to the Great Waters and recommending potential solutions in Reports to

Congress. In addition to these two agencies, other international, national, regional, and local

organizations are engaged in activities that seek to reduce sources and quantities of pollution to the Great

Waters and also contribute to the body of science relevant to the Great Waters program. This Report to

Congress, like the first two reports, describes the most recent activities of these programs, both within

and outside of EPA. 
Chapter I

Introduction and Background

Page I-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Increasingly, EPA is utilizing cross-program teams and partnerships with other agencies and

organizations to study and solve complex, “multimedia” environmental issues (i.e., issues that cut across

air, water, land, and biological resources). For example, the Clean Water Action Plan, issued by EPA in

1998, which includes many activities relevant to the Great Waters program, is a coordinated Federal

effort involving EPA and the Departments of Agriculture, Defense, Interior, and Commerce, all of which

have authorities affecting the quality of the Nation’s water resources. This Report to Congress describes

several such collaborative efforts that support targeted data gathering and decision making for multiple

objectives, including those of the Great Waters program. 

 

Because deposition of atmospheric pollutants to the Great Waters is a multimedia problem,

several media-based and geographically-based programs are part of EPA’s integrated efforts to address

pollution in the Great Waters, including the following.

C Office of Air and Radiation (OAR) administers the Great Waters program along with other

programs under the CAA that affect the Great Waters. For example, air regulations and

programs developed by OAR reduce emissions of air toxics and nitrogen from many mobile and

stationary sources of Great Waters pollutants of concern. Offices within OAR responsible for

air pollution control programs include (1) the Office of Air Quality Planning and Standards

(OAQPS), which has overall responsibility for the Great Waters, air toxics, and air quality

management programs; (2) the Office of Atmospheric Programs (OAP), which manages the

acid rain and global climate change programs; and, (3) the Office of Transportation and Air

Quality (OTAQ; formerly the Office of Mobile Sources or OMS), which is responsible for

regulating on- and off-road vehicles and fuels. 

C Office of Research and Development (ORD) undertakes and coordinates research and

monitoring programs that provide information for assessment of human health and

environmental risks associated with exposures to pollutants of concern in the Great Waters as

well as for risk management decisions. The ORD is the lead EPA office in developing a mercury

research strategy and is working closely with EPA’s Office of Prevention, Pesticides and Toxic

Substances (OPPTS) in preparing a dioxin reassessment.

C Office of Water (OW) leads numerous activities that are integral to the Great Waters program. 

For example, OW provides data on trends in fish and sediment contamination in the Great

Waters and is working to factor atmospheric deposition into waterbody-specific water pollution

standards. In addition, OW manages the Non-Point Source Control Program under section 319

of the Clean Water Act. Within OW, the Office of Wetlands, Oceans and Watersheds is

responsible for, among other things, coastal protection (e.g., the National Estuary Program) and

the TMDL determination. The Office of Science and Technology provides critical tools to help

understand and reduce water pollution, and, in cooperation with NOAA and other Federal and

State and tribal agencies, reviews and monitors fish and shellfish contamination across the U.S. 

C National Estuary Program (NEP), which is managed by OW, was established by EPA in 1987

to implement section 320 of the Clean Water Act. The purpose of the NEP is to restore and

enhance nationally significant estuaries that are threatened or impaired by pollution,

development, or overuse. Management decisions are made by conferences composed of EPA

and local stakeholder groups. The NEP currently includes 28 estuaries, several of which have

identified air deposition as a concern and have received Great Waters program funding to address

the problem.
Chapter I

Introduction and Background

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-5

C Chesapeake Bay Program Office (CBPO) represents EPA as a partner in the Chesapeake Bay

Program. This program was created in 1983 by an agreement between EPA, the State of

Maryland, the Commonwealths of Virginia and Pennsylvania, and the District of Columbia. The

Chesapeake Bay Program uses a cooperative, watershed approach to research and resolve public

health and environmental issues affecting the bay.

C Great Lakes National Program Office (GLNPO) is responsible for EPA activities specific to

the Great Lakes, including responsibilities defined by the Great Lakes Water Quality Agreement

with Canada, Great Lakes Program requirements under section 118 of the Clean Water Act, and

the Great Lakes Critical Programs Act of 1990. The GLNPO also supports EPA’s OAQPS and

Region V activities specific to the Great Lakes for the air toxics program under section 112 of

the CAA. In addition, GLNPO conducts and funds monitoring research in support of the Great

Waters program.

C Gulf of Mexico Program Office (GMPO) is a nonregulatory organization that sets

environmental goals and implements projects to protect the environmental resources of the Gulf

of Mexico. Partners in the GMPO include EPA, other governmental agencies (Federal, State,

and local), private and non-profit sector stakeholders, and interested citizens. The Gulf of

Mexico shoreline includes a substantial percentage of the Nation’s estuaries and other significant

coastal ecosystems.

C EPA Regional Offices (Regions I-X) are responsible for working directly with States, tribes,

and regional organizations to implement national environmental programs, including the Great

Waters program. For instance, Region I and Region II work with the States in the Northeast to

address pollution in the Lake Champlain Basin, as well as the National Estuary Programs from

Maine to New Jersey. 

In addition to the EPA Offices listed above, many others contribute to the integrated efforts as

well. For example, the Office of Solid Waste and Emergency Response (OSWER) provides Agencywide

policy, guidance, and direction for the EPA’s solid waste program and emergency response program. 

The Office of Enforcement and Compliance Assurance is responsible for leading the Agency in ensuring

compliance with the rules that limit pollution. The OPPTS leads the Agency in pollution prevention

activities, among many other activities. Chapter III discusses many of the programs led by these and

other offices.

The NOAA administers the 23 National Estuarine Research Reserves System (NERRS) sites –

all are coastal Great Waters – which were created in 1972 by the Coastal Zone Management Act. The

NERRS sites, which were selected to be representative of various regions and estuary types, are managed

cooperatively with the States to provide opportunities for long-term research, education, and stewardship. 

Research conducted at NERRS sites includes studies of the impacts of toxic pollutants deposited from

the atmosphere.

The NOAA also conducts or funds several other monitoring and research programs that

contribute to the Great Waters program. For example, the Atmospheric Integrated Research Monitoring

Program (AIRMoN) conducts daily deposition monitoring, the National Status and Trends Program

gathers and maintains data on the environmental quality of U.S. estuaries and coastal waters, and the

NERRS System-wide Monitoring Program currently gathers water quality and weather data. In addition,

NOAA plays a critical role in working with EPA to jointly assess the transport and deposition of nitrogen

and other pollutants on surface waters.
Chapter I

Introduction and Background

Page I-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Other involved participants include State, tribal, and local agencies, non-profit organizations,

private sector groups, industry and industry groups, universities, other countries, and international

research organizations. Relevant research and other activities of these partners are described throughout

the report. The combined activities of all of these partners are responsible for progress to date in

identifying, assessing, and resolving Great Waters problems, including problems associated with

pollutants deposited from air pathways.

GOVERNMENT GOALS SUPPORTED BY THE GREAT WATERS

PROGRAM AND ITS PARTNERS

The EPA’s Strategic Plan (U.S. EPA 1997c) defines ten strategic goals used by the Agency for

planning and resource allocation, as required by the Government Performance and Results Act (GPRA). 

The efforts by EPA, NOAA, and partners support the following GPRA goals:

1. Clean Air -- “The air in every American community will be safe and healthy to breathe . . . 

Reducing air pollution will also protect the environment, resulting in many benefits, such as

restoring life in damaged ecosystems and reducing health risks to those whose subsistence

depends directly on those ecosystems.”

2. Clean and Safe Water -- “All Americans will have drinking water that is clean and safe to

drink. Effective protection of America’s rivers, lakes, wetlands, aquifers, and coastal and ocean

waters will sustain fish, plants, and wildlife, as well as recreational, subsistence, and economic

activities . . . ”

3. Preventing Pollution and Reducing Risk in Communities, Homes, Workplaces and

Ecosystems -- “EPA will safeguard ecosystems and promote the health of natural communities

that are integral to the quality of life in this Nation . . .”

4. Reduction of Global and Cross-Border Environmental Risks -- “The U.S. will lead other

nations in successful, multilateral efforts to reduce significant risks to human health and

ecosystems . . . ”

5. Sound Science, Improved Understanding of Environmental Risk, and Greater Innovation

to Address Environmental Problems -- “EPA will develop and apply the best available

science for addressing current and future environmental hazards, as well as new approaches

toward improving environmental protection.”

These efforts support these goals either directly or by contributing information on atmospheric

deposition helpful to EPA’s place-based (i.e., geographically-based programs, such as GLNPO) or

media-oriented programs (e.g., programs in OW that focus on water resources). Specifically, the Great

Waters program and its partners help the Agency achieve atmospheric deposition objectives outlined in

the clean air and clean and safe water goals and the atmospheric transport and deposition component

related to international pollution transport goal. Furthermore, the aspects of the work devoted to

investigation and assessment of atmospheric deposition support EPA’s efforts under the sound science

goal to provide the best available science on which to base decisions on how best to reduce the presence

and effects of this pollution. As shown in later sections of the report, progress toward each of these goals

involves and emphasizes multimedia and multiprogram collaboration. 
Chapter I

Introduction and Background

1

 HCB is a product of incomplete combustion as well as a pesticide. In Chapter II of this report, HCB is

discussed under the pesticides pollutant group.

2

 There are different isomers of HCH of concern that can transform into other HCH isomers that have

different persistence and toxicity characteristics. 

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-7

I.B POLLUTANTS OF CONCERN

This report focuses on the 15 pollutants of concern addressed in the First and Second Great

Waters Reports to Congress. The general types of emission sources and uses (and use restrictions) of

these pollutants are summarized in Table I-1. In general, sources of these pollutants can include U.S.

short-range and long-range transport from stack emissions, natural emissions, re-emitted emissions from

natural and human-made sources, long-range transport from foreign countries, and cycling within the

global pool of each pollutant. 

As in the two previous reports, these pollutants are organized into the following pollutant groups

(with one change):

C Mercury and Mercury Compounds

C Other Metals

-- Cadmium and cadmium compounds

-- Lead and lead compounds

C Combustion Emissions

-- Polycyclic organic matter (POM), including polycyclic aromatic hydrocarbons (PAHs)

-- Dioxins (tetrachlorodibenzo-p-dioxin, 2,3,7,8-TCDD) and furans (tetrachlorodibenzofuran,

2,3,7,8-TCDF)

-- Hexachlorobenzene (HCB)1

C Nitrogen Compounds (including NOx, ammonia and ammonium, and organic nitrogen) 

C Banned and Restricted Use Substances

-- Polychlorinated biphenyls (PCBs)

-- Pesticides

- Chlordane

- DDT/DDE

- Dieldrin

- Hexachlorobenzene (HCB)1

- Hexachlorocyclohexane ("-HCH)2

- Lindane ((-hexachlorocyclohexane, or (-HCH)2

- Toxaphene

This last revised grouping is based on the fact that the use and manufacture of these pollutants

have either been banned or severely restricted under other Federal statutes, such as the Federal

Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Toxic Substances Control Act (TSCA). 
Chapter I

Introduction and Background

Page I-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

With these pollutants, in general, historical contamination (e.g., in sediments and landfills), and not

current national releases from U.S. industrial or agricultural activities, appears to be the problem. For the

most part, the sources of these pollutants to the Great Waters today include resuspension of contaminated

sediments, releases from contaminated soils, atmospheric deposition from long-range transport of

pollutants from foreign countries where uses are still permitted, and accidental releases from stockpiles

or intentional dumping. The revised grouping helps to organize research into these pollutants of concern

and management of the reduction of the risks they pose to the Great Waters (e.g., work under

international frameworks to reduce global releases, activities to remediate contaminated sediments).

Many programs and activities address these pollutants of concern either directly or indirectly and

through statutory requirements or voluntary initiatives. The above pollutants are of concern to multiple

programs because they share the problematic characteristics of toxicity, persistence, and/or potential for

long-range transport in the environment (e.g., via the atmosphere). Because of these properties, many of

these contaminants are ubiquitous in the environment and may accumulate to potentially harmful

concentrations in water, sediments, soil, or the food web. This presents difficult challenges and places a

premium on multimedia, interdisciplinary approaches for solving problems associated with these

pollutants.

Table I-2 provides examples of how the Great Waters pollutants of concern are being addressed

in the U.S. by closely related multimedia programs and other activities authorized by the CAA. All of

the programs and activities identified in this table, along with several others, are discussed later in the

report. Collectively, these programs and activities demonstrate EPA’s holistic perspective and steps

toward approaching the goals of clean air, clean water, and healthy ecosystems in an integrated manner. 

Building strong partnerships with other governmental agencies and stakeholders is a guiding

principle of EPA’s Strategic Plan and one of five key attributes of EPA’s reinvention plan (U.S. EPA

1997c). This report describes several ways in which EPA’s progress toward the Great Waters program

goals can be attributed to the collective efforts of many partners at the local, tribal, State, Federal, and

international levels. Table I-3 identifies some of the programs at different levels that address Great

Waters pollutants of concern. Each of these programs and activities is described later in this report.
Chapter I

Introduction and Background

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-9

Table I-1

Uses/Sources and U.S. Regulatory Status of Great Waters Pollutants of Concern

Pollutant Examples of Uses/Sources

Mercury and Compounds

Naturally occurring element often used in thermometers, electrical equipment (such as batteries and switching equipment), industrial control instruments, and industrial

processes (e.g., chlor-alkali plants). Released during combustion of fossil fuels (e.g., coal, oil); incineration of municipal, medical, and hazardous waste; and from

numerous manufacturing and natural processes (e.g., volcanic activity). Banned as a paint additive in U.S. in both interior (1990) and exterior (1991) paint. Being

phased out of batteries. Removed from catalysts, turf products, and explosives. 

Cadmium and Compounds Naturally occurring element used in metals production processes, batteries, and solder. Often released during combustion of fossil fuels and waste oil, and during

mining and smelting operations.

Lead and Compounds

Naturally occurring element historically used in gasoline and paint additives, and still used in storage batteries, solder, and ammunition. Released from many

combustion and manufacturing processes and from motor vehicles. Use in paint additives restricted in U.S. in 1971. U.S. restrictions on use in gasoline additives

began in 1973 and have continued through the present, with a major use reduction in the mid-1980s.

POM (includes PAHs) Naturally occurring substances that are by-products of the incomplete combustion of fossil fuels and plant and animal biomass (e.g., forest fires). Also, by-products

from steel and coke production and waste incineration.

Dioxins and Furans By-product of combustion of organic material containing chlorine, chlorine bleaching in pulp and paper manufacturing, and diesel-fueled vehicles. Also a contaminant

in some pesticides.

Nitrogen Compounds Naturally occurring substances from a variety of processes (e.g., microbial activities, lightning, biomass combustion) and by-products of power generation, industrial,

and motor vehicle fossil fuel combustion processes (NOx). Also, compounds used in fertilizers and released from agricultural animal manures (NH3).

PCBs

Industrial chemicals used widely in the U.S. from 1929 until 1978 for many purposes, such as coolants and lubricants and in electrical equipment (e.g., transformers

and capacitors). In the U.S., manufacture stopped in 1977 and uses were significantly restricted in 1979. Still used for some purposes because of stability and heat

resistance, and still present in certain electrical equipment used throughout the U.S.

Chlordane Insecticide used widely in the 1970s and 1980s. All U.S. uses except termite control canceled in 1978; use for termite control voluntarily suspended in 1988. Use of

existing stocks permitted.

DDT/DDE Insecticide used widely from introduction in 1946 until significantly restricted in U.S. in 1972. Still used in other countries. Used in U.S. for agriculture and public health

purposes only with special permits.

Dieldrin Insecticide used widely after introduction in late 1940s. Used in U.S. for termite control from 1972 until registration voluntarily suspended in 1987.

Hexachlorobenzene Fungicide used as seed protectant until 1985. By-product of chlorinated compound and pesticide manufacturing. Also a by-product of combustion of chlorinecontaining materials. Present as a contaminant in some pesticides.

Hexachlorocyclohexane Component of technical-HCH, an insecticide for which use is restricted in U.S., but which is used widely in other countries.

Lindane An insecticide used on food crops and forests, and to control lice and scabies in livestock and humans. Currently used primarily in China, India, and Mexico. U.S.

production stopped in 1977. Use was restricted in 1983; many uses are still registered, but are expected to be voluntarily discontinued in the future.

Toxaphene Insecticide used widely on cotton in the southern U.S. until the late 1970s. Most U.S. uses banned in 1982; remaining uses canceled in 1987.
Chapter I

Introduction and Background

Page I-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table I-2

EPA Multimedia and Cross-program Management of the Great Waters Pollutants of Concern

Great Waters Pollutant of

Concern

Selected Multimedia and Air Programs

Multimedia Activities Air Program Activities

PBT

Initiativea

Clean Water

Action Planb

Contaminated Sediment

Management Strategyc CAA Section 112 Activitiesd Other Major CAA Programse

Mercury and Compounds U U U

C Standards for Specific Pollutants

C MACT Program 

C Urban Area Source Program

C Utility Study

C Mercury Study

C NIEHS Fish Mercury Study

C Solid Waste Combustion

Cadmium and Compounds U U

C MACT Program

C Urban Area Source Program

C Utility Study

C Solid Waste Combustion

Lead and Compounds U U U

C Standards for Specific Pollutants 

C MACT Program

C Urban Area Source Program

C Utility Study

C Prevention of Accidental Releases

C Criteria Pollutant Program

C Solid Waste Combustion

C Fuels Program

POM (includes PAHs) U U U

C Standards for Specific Pollutants

C MACT Program

C Urban Area Source Program

C Utility Study

Dioxins and Furans U U U

C Standards for Specific Pollutants

C MACT Program

C Urban Area Source Program

C Utility Study

C Solid Waste Combustion

Nitrogen Compounds U U

C Prevention of Accidental Releases C Criteria Pollutant Program (NOx,

O3, particulate matter)

C Mobile Source Program

C Acid Rain Program (NOx)

C Solid Waste Combustion

PCBs U U U

C MACT Program

CUrban Area Source Program

Chlordane U U U C MACT Program

DDT/DDE U U U

Dieldrin U U U

Hexachlorobenzene U U U

C Standards for Specific Pollutants

C MACT Program

CUrban Area Source Program

C Utility Study
Chapter I

Introduction and Background

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-11

Table I-2 (continued)

EPA Multimedia and Cross-program Management of the Great Waters Pollutants of Concern

Great Waters Pollutant of

Concern

Selected Multimedia and Air Programs

Multimedia Activities Air Program Activities

PBT Initiativea Clean Water Action Planb Contaminated Sediment

Management Strategyc CAA Section 112 Activitiesd Other Major CAA Programse

Hexachlorocyclohexane U U

Lindane U U C MACT Program

Toxaphene U U U C MACT Program

a As discussed in Chapter III of this report, the Persistent Bioaccumulative Toxic (PBT) Chemicals Initiative is a cross-office EPA effort to coordinate

actions associated with these high-priority pollutants.

b Because the Clean Water Action Plan does not address a specific set of pollutants, any of the Great Waters pollutants of concern may be addressed

(see Chapter III of this report for more detail).

c Because the Contaminated Sediment Management Strategy does not address a specific set of pollutants, any of the Great Waters pollutants of concern

may be addressed (see Chapter III of this report for more detail).

d C Standard for specific pollutants = §112(c)(6); Sources accounting for 90 percent of the emissions of these seven pollutants (i.e., alkylated lead

compounds, POM, HCB, mercury, PCBs, dioxins and furans) are subject to regulation.

C MACT Program = §112(d) 

C Urban Area Source Program = §112(k)

C Utility Study = §112(n)(1)(A); Emissions of certain pollutants from electric utility steam generating units are evaluated for potential regulation.

C Mercury Study = §112(n)(1)(B); Emissions of mercury from electric utilities, municipal waste combustors, and other sources studied for potential

regulation.

C NIEHS Fish Mercury Study = §112(n)(1)(C); Report by the National Institute of Environmental Health Sciences on the “threshold” level for human health

effects from mercury.

C Prevention of Accidental Releases = §112(r)

e C Criteria Pollutant Program = §108

C Mobile Source Program = Subchapter II

C Solid Waste Combustion = §129 

C Acid Rain Program = Subchapter IV-A
Chapter I

Introduction and Background

Page I-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table I-3

Great Waters Pollutants of Concern Addressed by Selected Waterbody, Regional, and International Activitiesa

Pollutant

Regional and Waterbody-specific Programs International Activities

Great

Lakes

Programsb

Lake

Champlain

Basin Programc

Chesapeake

Bay Programd

Estuarine

Initiativese

Binational

Strategy

International

Joint

Commission

LRTAP NAFTA UNEP

Mercury and

Compounds U U U U U U U U

Cadmium and

Compounds U U U U U

Lead and Compounds U U U U U U U

POM (includes PAHs) Uf U U U U Uf Ug Ug

Dioxins and Furans U U U U U Ug U Ug

Nitrogen Compounds U U U U

PCBs U U U U U U Ug Ug

Chlordane U U U U U Ug U Ug

DDT/DDE U U U U U Ug Ug

Dieldrin U U U U U U Ug Ug

Hexachlorobenzene U U U U U Ug Ug

Hexachlorocyclohexane U U U Ug Ug

Lindane U U U Ug U Ug

Toxaphene U U U U U U Ug Ug

a See Chapter III of this report for information on the status of all of these and other programs addressing the Great Waters pollutants of concern.

b Integrated Atmospheric Deposition Network (IADN); Great Lakes Emissions Inventories; Lake Michigan Mass Balance Study; Great Lakes Lakewide

Management Plans (LaMPs) and regional action plans (RAPs)

c Includes Group 1 through Group 4 Toxic Substances of Concern for the Lake Champlain Basin Program (LCBP). Ammonia, a Group 3 Toxic Substance

of Concern, is included in the table as a nitrogen compound.

d Includes Toxics of Concern and Chemicals of Potential Concern for the Chesapeake Bay Program.

e Any of the Great Waters pollutants of concern could be a concern at a specific NEP or NERRS site.

f Benzo[a]pyrene

g Persistent organic pollutants (POPs) are included as pollutants of concern under the United Nations Economic Commission for Europe Long-Range

Transboundary Air Pollution (LRTAP) initiative, as well as the United Nations Environment Program (UNEP) POPs initiative. This constituent is a POP.
Chapter I

Introduction and Background

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page I-13

I.C GOALS OF THE THIRD REPORT TO CONGRESS

The goals of the Third Report to Congress are to discuss the current state of knowledge regarding

atmospheric deposition of pollutants to the Great Waters based on the information available and program

activities since June 1996 (the end of the timeframe for information presented in the Second Report to

Congress) and to describe any necessary revisions to requirements, standards, and limitations pursuant to

the CAA and other Federal laws. The report is organized into four chapters that summarize the

following:

C Observed and anticipated spatial and temporal changes in airborne emissions, loadings, and

effects of pollutants of concern (Chapter II);

C Programs and activities that have been undertaken to address pollutants of concern since the

Second Report to Congress (Chapter III);

C Advancements in scientific research methods, environmental models, and data sources that

improve our understanding of and abilities to address the public health and environmental risks

posed by the pollutants of concern in the Great Waters (Chapter IV); and,

C Conclusions and recommendations to help further national, regional, and waterbody-specific

activities related to the Great Waters program (Chapter V).

In addition, this report identifies important remaining uncertainties, such as those that limit EPA’s ability

to assess the links between pollutant sources, loadings, and effects. The research findings, conclusions,

and recommendations presented in this report will be used to further understand and promote reductions

of overall contaminant loadings to the Great Waters.

The report focuses on the scientific and programmatic progress that has occurred since the

previous report and presents information according to the major issues of concern (e.g., trends in

loadings and effects, program progress, scientific tools) from a national perspective. Regional or

waterbody-specific examples are presented in the context of a national-level picture of progress toward

the goals of the Great Waters program. For more detail on specific regions or waterbodies, readers are

referred to the many other publications or Internet sites that specifically address those areas (see

Appendix A). In addition, the report includes an index of waterbodies to enable readers to identify all

information related to a specific waterbody that is presented in this report.

The information in this report was collected from several sources. The references cited are

generally from published peer-reviewed journals, government reports, and conference proceedings. The

report uses a variety of sources that provide relevant new information on Great Waters issues and

generally addresses information released in the past 2 years. In some cases, large summary reports were

used and, therefore, primary sources of information are not cited. In general, literature published from

the summer of 1996 to the fall of 1998 is included.

In addition to literature searches for updated information, EPA obtained current scientific and

programmatic information about atmospheric deposition to the Great Waters through personal interviews

with and direct input from various researchers and program participants. Many of the waterbody-specific

activities highlighted in this report, for example, were provided by the EPA offices that coordinate

investigation, restoration, and maintenance efforts of the waterbody (e.g., Great Lakes National Program

Office, EPA Region V Air and Radiation Division, Chesapeake Bay Program Office, Gulf of Mexico

Program Office).
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-1

Pollutant-Specific Changes ................... II-3

<Mercury and Compounds ................... II-4

<Other Metals (Lead and Cadmium) .......... II-19

<Combustion Emissions .................... II-31

<Nitrogen and Compounds .................. II-40

<Banned and Restricted Use Substances ....... II-58

Cross-Pollutant Trends ..................... II-67

<Fish Consumption Advisories .............. II-68

<Water Quality Assessments ................ II-69

<NOAA’s National Status and 

Trends Program ........................ II-70

<National Sediment Quality Survey ........... II-73

<Chesapeake Bay Program ................. II-73

<Lake Champlain Sediment Toxics Assessment

Program .............................. II-75

<San Francisco Estuary Regional Monitoring

Program for Trace Substances ............. II-76

Don Simonelli (courtesy Michigan Travel Bureau)

CHAPTER II

ENVIRONMENTAL PROGRESS

This chapter attempts to answer the question: Is the problem associated with atmospheric

deposition of the pollutants of concern in the Great Waters getting better or worse? It is not intended to

summarize the myriad of regulatory and nonregulatory activities and accomplishments designed to solve

the problem, a discussion which is reserved for Chapter III. Likewise, this chapter is not intended to

cover new scientific research or analytical tools that help improve the understanding of pieces of the

problem, such as the details of pollutant behavior in the atmosphere or the ways pollutants are exchanged

between air and water. This more science-oriented update is provided in Chapter IV, although some of

the results of this research are included in this chapter.

This chapter summarizes recent information on the changes in sources and emissions (including

transport and transformation), loadings, and exposure and effects of pollutants of concern in the Great

Waters, and is organized into two sections. The first section, organized by pollutant groups (see Chapter

I), provides information for each pollutant of concern. The second section discusses trends from

assessments that address multiple pollutants. These discussions reflect results of new studies published

since the Second Report to Congress, some of which address time periods prior to the Second Report to

Congress. They focus on the observed changes over time, including temporal and spatial changes in

sources, emissions, loadings, exposure, and effects reported in new studies combined (where appropriate)

with information presented in the First and Second Reports to Congress. 

As background for discussing these questions, it is helpful to review the components of the

atmospheric release, transport, and deposition processes (Figure II-1), as well as environmental and

public health effects.

Pollutant emissions to the atmosphere can be characterized as “human-made” or

“anthropogenic” (i.e., released by human activities), “natural” (i.e., releases of geologically-bound

pollutants by natural processes), or “re-emitted” (i.e., the mass transfer to the atmosphere by
Chapter II

Environmental Progress

Page II-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

biologic/geologic processes for previously deposited pollutants). Examples of human-made emissions

are those associated with industrial stacks, municipal waste incinerators, agricultural activities (e.g.,

pesticide applications, manure management), and vehicle exhaust. Examples of natural emissions

include those associated with volcanic eruptions, windblown gases and particles from forest fires,

windblown dust and soil particles, and sea spray. In many cases, however, it is difficult to determine if

the pollutant inputs are from natural or anthropogenic sources. 

Figure II-1

Atmospheric Release, Transport, and Deposition Processes

Airborne releases or emissions of pollutants can be transported away from the source to other

locations. Depending on the weather conditions and the chemical and physical properties of the

pollutant, air pollutants can be transported varying distances and may undergo physical, chemical, and/or

biological transformations during transport (U.S. EPA 1997b). As mentioned in Chapter I, all of the

Great Waters pollutants of concern are known to be subject to long-range transport.

Pollutant loadings to waterbodies can occur through many different pathways, including

connecting streams and rivers, groundwater inflow, land surface runoff, rerelease of pollutants from

sediments, and atmospheric deposition processes. Atmospheric inputs to waterbodies also occur through

several mechanisms (Figure II-1). Pollutants that are released to the air can be deposited to land areas,

tributaries, or directly to the waterbody by wet or dry deposition. The process of wet deposition refers to

the removal of air pollutants from the air by a precipitation event, such as rain or snow. The process of

dry deposition refers to the removal of aerosol pollutants through eddy diffusion and impaction, large

particles through gravitational settling, and gaseous pollutants through direct transfer from the air to the

water (i.e., gas exchange). Air pollutants can also enter the waterbody through indirect deposition which

occurs when an air pollutant is deposited to a land area or tributary and is then carried into a waterbody

by other routes, such as storm water runoff or inflow from tributaries. Therefore, in these mechanisms,

loadings to a waterbody are both directly and indirectly affected by air pollutant emission levels.

Loadings can be expressed as the total amount of a pollutant entering a waterbody over a

specified time period (e.g., kg/year) or as a loading rate (e.g., μg/m2/year). The tendency of a specific

pollutant to enter a waterbody through wet deposition, dry deposition, or gas exchange is related to the
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-3

physical and chemical properties of the pollutant as well as to current and local meteorology. 

Determining the relative atmospheric loading – how the loading from atmospheric deposition compares

to that from other pathways, such as groundwater seepage and inflow from connecting surface

waterbodies, where portions of the pollutant load may not be of atmospheric origin – is as important as

determining total loading. Uncertainties exist, however, in loadings estimates because of errors inherent

in sampling methodologies and the assumptions about a specific chemical’s behavior that are used to

develop deposition estimates. Furthermore, monitoring networks have spatial and temporal limitations,

making it difficult to accurately and reliably quantify atmospheric deposition inputs.

Air pollutant loadings to the waterbody may contribute to environmental and public health

effects, such as when water quality and drinking water standards are exceeded (where such standards

exist). These standards provide a measure of degradation and possible exposures of plants, animals, and

humans to potentially harmful levels of pollutants. The number and magnitude of water quality and

drinking water standard exceedances in a waterbody may be affected, in part, by changes in pollutant

loadings from the atmosphere, which in turn, are affected by changes in atmospheric emissions of those

pollutants. Potential ecological and human health effects from exposures to the Great Waters pollutants

of concern are not discussed comprehensively in this report because the Second Report to Congress

focused on effects from exposures. This report focuses more on recent literature on trends, such as

contaminant levels found in biota as well as fish consumption advisories. In many cases, however,

information on trends in exposure levels or observed effects was not available. Therefore, surrogate

measures of exposure, such as trends in concentration levels in environmental media or biota, are

presented. Note that the presence of a pollutant in the environment only translates into an exposure for

humans and/or biota if an exposure pathway exists.

The understanding of how the pieces of this complex puzzle fit together continues to increase,

although uncertainty and gaps in information remain. This chapter reports on new information that helps

to establish the links between emissions, transport and transformation, loadings, and effects. It also

includes information on the various elements that contribute to establishing these links. For example, it

includes inventories of emission sources, which are essential inputs to models that predict pollutant

loadings to waterbodies.

POLLUTANT-SPECIFIC CHANGES

For each pollutant or pollutant group, information on sources and emissions is presented first,

followed by new loadings information, and then by new information on exposure and effects. If no new

information is available on one of these topics for a particular pollutant or pollutant group, that topic

simply is not addressed. The second part of this section, Cross-Pollutant Changes, summarizes results

from several EPA and other agency programs and projects that are not limited to individual pollutants,

but rather provide information on many pollutants in a manner making it more appropriate to present the

information as a cohesive piece as opposed to dividing the information among the pollutant groups.

Although a large amount of research has been and continues to be conducted related to the

release, transport, loadings, exposure, and effects of Great Waters pollutants of concern, information

gaps and uncertainties remain. In general, the information presented below consists of the highlights of

the studies, and details on assumptions and uncertainties are not always presented. However, most if not

all of the studies discussed below are associated with some type of uncertainty (e.g., related to the

number of measurements, the time period of the study, or the lack of standard measurement methods). 

The original study should be consulted for these details for a better understanding of the assumptions

used and resultant uncertainties. While uncertainties and information gaps continue to exist, it should be

noted that research is ongoing to attempt to reduce them.
Chapter II

Environmental Progress

Page II-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

HIGHLIGHTS

Mercury

' Sources. The largest human-made sources of

mercury emissions in the U.S. are coal-fired utility

boilers, medical waste incinerators, and municipal

waste combustors. Mercury can also be emitted

from natural sources, such as volcanic activities. 

Mercury releases from human activities today are

adding to the global reservoir of mercury cycling

between land, water, and air that is the result of

natural releases and past human activities. Humanmade emissions of mercury have declined since

1990, due chiefly to the phase-out of mercurycontaining products.

' Loadings. Atmospheric deposition is a principal

source of mercury to several Great Waters, followed

by riverine inputs. Urban areas in proximity to the

Great Waters can also contribute significantly to

loadings via the atmosphere and urban runoff. 

Deposited mercury that is buried or immobilized in

soils and sediments can be transported to 

waterbodies by high streamflow events like storms 

and snowmelt. Forested watersheds retard mercury

transport to the waterbody compared to agricultural

or urban watersheds. 

' Human and Ecological Exposure and Effects. 

Consumption of contaminated fish represents the

dominant pathway for both human and wildlife

exposures to methylmercury. The typical U.S.

consumer of fish from restaurants and grocery stores

is not believed to be at risk. Rather, consumers who

eat more fish than is typical or fish that are more

contaminated than typical fish may be at risk of

adverse effects. Because the developing fetus is

regarded as the most sensitive to the effects of

methylmercury, women of childbearing age are the

population of greatest concern. State and tribal fish

consumption advisories have been implemented to

warn people about the related risks. Measurements

of mercury in loons indicate up to 30 percent of

male loons in the northeastern U.S. have mercury

levels sufficiently high to cause adverse effects. 

MERCURY AND COMPOUNDS

Mercury is a cationic metal – it has

characteristics of both a metal and an organic

compound (e.g., it is persistent in the

environment, bioaccumulates in the food chain,

and vaporizes at low temperatures). Mercury is

an excellent conductor of electricity and is

widely used in products such as batteries,

electric switches, thermostats, thermometers, and

barometers as well as a number of industrial

processes including pharmaceutical preparations

and the production of caustic soda and chlorine. 

Mercury can exist in three oxidation

states: Hg0

 (metallic), Hg2

2+ (mercurous), and

Hg2+ (mercuric). The oxidation state strongly

influences the properties and chemical behavior

of mercury. For example, mercurous and

mercuric mercury can form numerous inorganic

and organic chemical compounds; however,

mercurous mercury is rarely stable under

ordinary environmental conditions. Most of the

mercury encountered in water, soil, sediment,

and biota is in the form of inorganic mercuric

salts and organomercurics (i.e., chemical

compounds with a covalent Hg-C bond, rather

than inorganic mercury compounds that simply

associate with organic material in the

environment). The mercury compounds most

likely to be found under environmental

conditions include the following: the mercuric

salts HgCl2, Hg(OH)2, and HgS; the

methylmercury compounds, methylmercuric

chloride (CH3HgCl) and methylmercuric

hydroxide (CH3HgOH); and, in small fractions,

other organomercurics (i.e., dimethylmercury

and phenylmercury) (U.S. EPA 1997e). The

mercury compounds that are of highest concern in terms of exposure and toxicity to humans and biota are

the methylated mercury compounds. The Mercury Study Report to Congress (U.S. EPA 1997e) provides

additional background information on mercury and mercury compounds.

Sources of mercury emissions to the air in the U.S. are ubiquitous and can be broadly classified

as belonging to one of three types:

1. Re-emitted mercury – the re-emission of mercury to the atmosphere by biologic and geologic

processes from mercury that was previously deposited to the earth’s surface following either

anthropogenic or natural releases. For example, a large portion of the deposited mercury is the

result of past human-made releases as well as releases from natural sources that previously were

sequestered (e.g., arctic tundra, ice sheets, oceans and wetlands);
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-5

2. Natural mercury emissions – the mobilization or release of geologically-bound mercury by

natural processes; or

3. Anthropogenic mercury emissions – the mobilization or releases of mercury by human activities.

Atmospheric deposition of mercury occurs primarily through two processes: scavenging of

particulate matter by precipitation and conversion of elemental mercury (Hg0) to ionic mercury during

rain formation. Dry deposition of reactive gaseous (Hg2+) and particulate mercury is also thought to be

an important process. The three dominant mercury forms act differently in the environment:

C Hg0 can be transported in the atmosphere for thousands of miles around the globe and deposits

very inefficiently because it is insoluble in water and is less chemically reactive; 

C Hg2+ in the gas-phase may be removed from the atmosphere within a few ten to a few hundred

miles of the source because it is highly water soluble and reactive; and,

C Particulate-phase mercury may be deposited at intermediate distances from the source, depending

on the size of the aerosol (Schroeder and Munthe 1998).

Current anthropogenic mercury emissions are only one component of the global mercury cycle. 

The amount of mercury in the land, water, and air at any one location is comprised of mercury from the

natural global cycle, the global cycle perturbed by human activities, as well as regional sources and local

anthropogenic sources. In addition to air emissions, other sources of mercury include direct water

discharges or past uses of mercury, such as fungicide application to crops. Current research continues to

indicate that natural sources, industrial sources, and recycled anthropogenic mercury each contribute to

about one-third of the current mercury burden in the global atmosphere (Pirrone et al. 1996). However,

as discussed further in Chapter IV, new measurement methods suggest that natural mercury emissions

rates from mercury-rich soils and bedrocks may be larger than past estimates. It is important to

understand the source of mercury and the amount of mercury contributed by each source type so that the

most efficient control strategies can be devised.

Given the complexities of the global mercury cycle, much of the research in recent years focused

on the environmental fate of mercury and the extent of current contamination in the environment. The

state of the science at this time does not provide a complete answer to the question of whether the

problem is improving. There is a general downward trend in anthropogenic mercury emissions in the

U.S., although emissions from many CAA source categories are not included in this assessment. 

Atmospheric deposition of mercury to an adjacent waterbody is primarily a function of the amount of

particulate-phase and reactive gaseous mercury emitted, the proximity of the source to the waterbody,

and meteorological conditions. The National Atmospheric Deposition Program - Mercury Deposition

Network (NADP-MDN) has been used to collect weekly wet deposition data for the past 4 years in some

locations; however, these early data are not robust enough to discern trends. Additional monitoring data

(which includes both wet and dry deposition measurements) from high quality stations over a longer

period are necessary for effective trends analyses. These measurements must be performed to allow for

meteorological analysis and identification of source contributions to the measured mercury. In general,

the research described in this section represents an important step forward in understanding the fate of

mercury in the environment and will continue to form the scientific basis for measures taken to address

the problem.
Chapter II

Environmental Progress

Page II-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Mercury Emissions

Estimates of the global contribution of mercury emissions to the atmosphere from anthropogenic

sources are 2,000 to 4,000 tons per year (tpy) and from natural sources are 2,200 to 4,000 tpy, resulting

in total mercury air emissions of 4,200 to 8,000 tpy (Pirrone et al. 1998). In comparison, U.S. mercury

air emissions for the 1994-1995 timeframe are 158 tpy, as reported in EPA’s Mercury Study Report to

Congress (Table II-1) (U.S. EPA 1997e). Roughly 87 percent of national mercury emissions in the U.S.

are from combustion sources, including waste and fossil fuel combustion. 

A recently identified source of mercury to the atmosphere is emissions of elemental mercury gas

(Hg0) from soils that have been amended with municipal sewage sludge. Carpi and Lindberg (1997),

using a field chamber and soil amended with sewage sludge, found that sludge application to soil

increased soil Hg0 releases by up to two orders of magnitude. The researchers estimated that land

application of sewage sludge in the U.S. and European Union may account for approximately 5 x 106

g/year (5 metric tons/year) of Hg0 released to the atmosphere based on the area of land amended each

year and measured Hg0

 emission rates. 

While there is a growing body of data on the total amount of mercury emitted from different

source types, data on the form (or species) of mercury emitted remain a critical research need. The

Mercury Study Report to Congress (U.S. EPA 1997e) estimated that anywhere from 0 to 73 percent of

the mercury emitted from different source categories is in the form of divalent mercury (Hg2+), the form

that deposits and contributes the most to methylmercury concentrations in soil, water, sediment, and

biota. There is, however, considerable uncertainty about the amounts of different mercury species

emitted from some industrial sources.

The emission inventories provide a snapshot of recent emissions and indicate a downward trend

in U.S. emissions between 1990 and 1995. This downward trend follows a general decline in domestic

mercury uses and reduced emissions from waste combustion sources (including municipal waste

combustors and medical waste incinerators). Industrial demand for mercury peaked in 1964 and fell 75

percent between 1988 and 1996. This decline largely reflects the phaseout of mercury in household

batteries and paint. The rate of decline, however, has slowed since 1990. Future trends in mercury

emissions from fossil fuel combustion sources, which currently represent a large portion of national

mercury emissions, are dependent on future energy needs and fuel use. Mercury emissions from

municipal waste combustors and medical waste incinerators, which also are large national sources of

mercury emissions, are expected to continue to decline from 1995 through 2000 due to new regulations

(see Chapter III) (U.S. EPA 1997e). 

It should be noted that several uncertainties exist with the mercury emissions inventory. For

example, not all source categories are included (e.g., landfills), and recent data submitted to EPA by the

Chlorine Institute indicate that current emissions may be underestimated. Furthermore, mercury

emissions from coal-fired electric utilities are expected to increase in future years, based on estimated

changes in emissions from implementation of the acid rain program and projected trends in fuel choices

and electric power demands in the year 2010 (U.S. EPA 1998p). As noted earlier in this section, the

speciation of mercury emitted is important in determining its transport and fate, yet remains a key

uncertainty. The EPA has worked with the Department of Energy and the American Society for Testing

and Materials to develop a standard method for measuring speciated mercury from utility boilers. The

EPA is also working to refine this method for other source categories, such as incinerators. The electric

utility industry is currently conducting speciated mercury emission testing on a subset of coal-fired

facilities, as discussed in the hazardous air pollutant section of Chapter III. Finally, in order to better

understand the relative contribution of mercury to the environment from anthropogenic sources, further
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-7

research is needed into the level of natural emissions as well as the amount and original source of

mercury that is re-emitted to the atmosphere after being deposited to soils, watersheds, and ocean waters. 

Although considerable uncertainty still exists, it has become increasingly evident that anthropogenic

emissions of mercury to the air rival or exceed natural inputs (U.S. EPA 1997e).

Table II-1

National Anthropogenic Mercury Air Emissions

(Based on 1994-1995 Inventory; U.S. EPA 1997e)

Source Category

1994-1995

Anthropogenic Air

Emissions (tons/year)

Percent Contribution to

Total U.S. Anthropogenic

Air Emissions

Utility boilers: coal combustion, oil, and natural gas 52 33

Municipal waste combustion 30 19

Commercial/industrial boilers: coal and oil 28 18

Medical waste incineration 16 10

Chlor-alkali production 7 4

Hazardous waste combustors 7 4

Chlor-alkali 7 4

Portland cement, excluding hazardous waste-fired 5 3

Residential boilers: oil and coal 4 2

Pulp and paper manufacturing 2 1

Others (<1percent each) a 3 2

Total U.S. Anthropogenic Mercury Air Emissions 158b,c 100b,c

a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in Appendix B.

b

 This value represents anthropogenic mercury air emissions in the U.S. only.

c

 Values do not add exactly due to rounding.

Mercury Deposition in the U.S.

Once in the air, mercury can be deposited locally or widely dispersed and transported long

distances from emission sources. How far it travels and where it is deposited depends in part on the

chemical and physical form of the mercury emitted. Elemental mercury may be transported in the

atmosphere for relatively long periods (approximately 1 year), allowing its distribution over long

distances, both regionally and globally, before being deposited to the earth. In contrast, the residence

time of mercuric (Hg2+) compounds in the atmosphere is generally believed to be a few days or less,

resulting in deposition closer to sources. Mercury also differs from other metals because it is readily reemitted to the atmosphere following deposition and chemical transformation. In summary, principal

factors that contribute to the modeled and observed patterns of mercury deposition are (1) the emission

source locations and characteristics (e.g., stack height); (2) the amount of Hg2+ and particulate mercury
Chapter II

Environmental Progress

Page II-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

emitted; (3) atmospheric chemical and physical properties; (4) uncertainties associated with the

emissions inventories, both in the magnitudes and the chemical forms emitted; (5) climate and

meteorology, and (6) treatment of natural sources and re-emission within the modeling domain. 

Because of the influence of the above six factors on mercury deposition, modeling of mercury

transport and deposition at different spatial scales (e.g., national, regional, and local) results in slightly

different information appropriate to each scale. Modeling at the local scale (i.e., approximately 100 km),

can provide more specific deposition estimates for a specific waterbody, but requires meteorological

modeling at the appropriate scale and up-to-date information on the amount of divalent and particulate

mercury emitted from the local sources. Recent studies in the Great Lakes region and in Florida show

that mercury emissions on local scales can greatly influence loadings in some locations when local

sources have significant emissions of divalent and particulate forms of mercury. For example, the South

Florida Atmospheric Mercury Monitoring Study (SoFAMMS) collected daily event precipitation samples

at 17 sites for 1 month and, using a suite of chemical and meteorological data, was able to demonstrate

that local anthropogenic sources strongly influence mercury wet deposition levels (see Section III.C for

additional information on SoFAMMS) (Dvonch et al. 1998). National modeling of emissions and

meteorology, on the other hand, can assist in answering some questions, but should not be applied to

regional or local analyses without critical review. The various forms of mercury in emissions are all

important in predicting atmospheric transport and deposition patterns, and care must be taken in

estimating local deposition or longer range impacts.

For the Mercury Study Report to Congress, EPA used the Regional Lagrangian Model of Air

Pollution (RELMAP) to model mercury emissions from the continental U.S. to estimate the amount of

mercury being deposited to the U.S. The model inputs included meteorological data from 1989, the U.S.

emissions inventory of 158 tons/year (U.S. EPA 1997e), and assumptions about the chemical species of

mercury emitted from various source types. The results showed total deposition (i.e., wet and dry

deposition of all forms of mercury) to be over 10 Fg/m2 throughout most of the continental U.S. east of

the Mississippi River, with values over 30 Fg/m2 for the northeast corridor and other urban areas. The

highest mercury deposition rates were predicted to occur in the southern Great Lakes and Ohio River

valley, the Northeast, and scattered areas in the South (with highest deposition rates in the Miami and

Tampa areas). Deposition of mercury is strongly influenced by the magnitude of emissions, the chemical

species of the emitted mercury (ionic and particulate-bound forms of mercury being the most readily

deposited), ozone and soot concentrations, and total annual precipitation. 

On a national basis, the computer simulation suggested that about one-third (~ 52 tpy) of U.S.

anthropogenic mercury emissions is deposited within the lower 48 States. The remaining two-thirds (~

107 tpy) of mercury emissions are transported beyond U.S. borders. In addition, the simulation suggests

that another 35 tpy of mercury from the global reservoir (which includes mercury from U.S. emissions)

are deposited in the U.S., resulting in a total deposition of roughly 87 tpy. Note, however, that the results

of the simulation include some uncertainty, as discussed in more detail in the following paragraph. 

According to the simulation, 98 percent of the deposited mercury of anthropogenic origin was emitted in

the form of ionic mercury or particulate mercury. The emissions inventory and estimated

chemical/speciation profiles indicate that of all combined ionic and particulate mercury emissions, 29

percent is from coal-fired electric utility boilers, 25 percent is from municipal waste combustion, 18

percent is from medical waste incineration, 16 percent is from coal-fired commercial and industrial

boilers, and 12 percent is from all other modeled sources. The methods for developing these mercury

emission estimates and speciation profiles are described in detail in volumes I and II of EPA’s Mercury

Study Report to Congress (U.S. EPA 1997e). 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-9

Mercury Emission Inventory by Percent

Contribution by Source Category for Eight

Northeast States

o Municipal waste combustion -- 45 percent

o Non-utility boilers -- 18 percent

o Electric utility boilers -- 13 percent

o Manufacturing sources -- 7 percent

o Area sources -- 6 percent

o Sewage sludge incineration -- 6 percent

o Medical waste incineration -- 5 percent

As the Mercury Study Report to Congress explains, there are a number of uncertainties in the

RELMAP analysis, with a large degree related to the state-of-the-science on chemical and physical forms

of mercury air emissions and their chemical and physical transformations in the atmosphere. The model

seems most sensitive to the speciation of mercury emissions. Speciated emissions data remain a critical

research need, as discussed above in the section on mercury emissions. In addition, atmospheric

chemistry data are incomplete in the model. Furthermore, there is inadequate information on the

atmospheric processes that affect wet and dry deposition (U.S. EPA 1997e). (Note that other sections of

this report describe additional research and model development activities in these areas.) 

To test the validity of the model, the wet deposition results from the RELMAP simulation were

compared to limited measured data from the Mercury Deposition Network (MDN). The RELMAP

estimates agreed with actual measurements within a factor of two in most cases and tended to

underestimate measured wet deposition. Overall, the RELMAP model seemed to produce reasonable

spatial patterns of annual wet deposition. Better spatial coverage by a long-term deposition network is

needed to better evaluate the model. In addition, the high deposition rates estimated for some urban areas

could not be verified because measurement data in urban areas are lacking (U.S. EPA 1997e).

In addition to the Mercury Study Report

to Congress, there have been a number of other

recent modeling and monitoring studies of

mercury deposition. For example, a regionalscale analysis, performed by the Northeast States

and Eastern Canadian Provinces in collaboration

with EPA, also illustrates the importance of local,

regional, and global sources to mercury

deposition levels (NESCAUM 1998). The

purpose of this study was to determine whether

deposition in the Northeast could be attributable

to sources within the region or to long-range

transport of mercury from upwind States. In this analysis, a RELMAP simulation suggested that

approximately 47 percent of the modeled deposition in the Northeast is attributable to sources in the

region, while approximately 30 percent is attributable to sources located outside the region. The

remaining 23 percent was estimated to be from the global atmospheric reservoir, which includes mercury

from U.S. emissions. The accompanying text box lists the source categories contributing to mercury

emissions in the Northeast. As with the national EPA study, combustion sources account for more than

85 percent of the mercury emissions. Note, however, that the results of the simulation include

considerable uncertainty.

The modeling predictions described above are based on average emissions over a year and as

such do not provide an indication of trends over time. Two ways to assess trends in emissions and

deposition are to consistently measure deposition over a wide geographic area over a long period of time,

or to analyze sediment cores. Mercury monitoring of wet deposition at a number of sites began recently,

and there are not enough data at present to evaluate trends over a widespread area. The Mercury

Deposition Network (MDN), which began as a transition network of 17 sites in 1995, became an official

subnetwork of NADP in 1996. Currently, nearly 40 sites are in operation throughout the U.S. and

Canada, with sites concentrated on the east coast and in the Great Lakes basin (Figure II-2). However,

the network is relatively sparse in its overall coverage, introducing uncertainty into trends analyses. The

objective of the MDN is to develop a long-term database of weekly total mercury concentrations in

precipitation and the annual and seasonal flux of total mercury in wet deposition. The present sites were

not selected to be representative of the region and, in some cases, are highly influenced by local emission 
Chapter II

Environmental Progress

Page II-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-2

Monitoring Sites of the Mercury Deposition Network – 1999
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-11

sources. Site sponsors consist of U.S. and Canadian government agencies, State government agencies,

universities, associations, and consulting firms. Currently, MDN data are available for 1996 and 1997. 

Available MDN monitoring data from 1996 and 1997 indicate that the volume-weighted mean

concentration of total mercury in precipitation from 22 sites ranged from 6.0 to 18.9 ng/L and annual

deposition of mercury ranged from 2.1 to 25.3 μg/m2 (or 2,100 to 25,300 ng/m2). In 1997, average

mercury concentrations in rain ranged from 6.2 to 18.3 ng/L at the 21 sites that had a full year of

monitoring data and the average concentration for all sites was 10.6 ng/L. In 1996, average mercury

concentrations at nine sites with a full year of data ranged from 6.0 to 14.1 ng/L with an average for all

sites of 10.2 ng/L. In 1997, the annual average wet deposition of mercury for 21 sites ranged from 4.3 to

25.3 μg/m2 (or 4,300 to 25,300 ng/m2), whereas in 1996, the annual average wet deposition of mercury

for nine sites ranged from 6.3 to 19.7 μg/m2 (or 6,300 to 19,700 ng/m2). In the eastern U.S., average

summer mercury concentrations are more than double winter concentrations and average summer

deposition values are more than three times winter values. This can be explained by higher

concentrations of mercury in the rain and higher rainfall amounts during the summer. One interesting

finding from the 1996 and 1997 MDN data is that several individual weeks were associated with

unusually high mercury deposition amounts as a result of heavy rainfall and above average mercury

concentrations. Based on National Weather Service information, the storms that contributed the

precipitation in these weeks tracked along the east coast, including New Jersey, New York City,

Providence, and Boston. Therefore, it is likely that emissions of mercury from these urban centers

entered the air mass of the storm and were deposited at these MDN sites (Sweet et al. 1999). 

While the MDN monitoring sites have not been in operation long enough to discern any temporal

trends in mercury levels, one monitoring station has been in operation in the Lake Champlain basin at

Underhill, Vermont since 1992. This is now the longest continuous monitoring program in the world for

total mercury wet deposition, ambient particulate phase mercury, and ambient total gas phase mercury. 

Results do not show long-term trends in atmospheric mercury concentrations except perhaps for a

downward trend for vapor phase mercury. Based on monitoring of wet deposition and modeling of dry

deposition, total annual deposition of mercury in 1993 was estimated at 15.1 μg/m2 (or 15,100 ng/m2). 

However, research suggests that the dry deposition flux of mercury may be much greater and re-emission

of mercury from forest ecosystems may be significant, introducing considerable uncertainty in the total

wet plus dry deposition estimates (Hanson et al. 1995, Rea et al. 1998, Scherbatskoy et al. 1999, 1998,

1997).

The Underhill monitoring data collected between December 1992 and December 1997 also show

seasonal variations. Deposition peaked in summer months when mercury concentrations in precipitation

are highest, while the concentration of mercury vapor in the air showed only slight seasonal variation. 

The seasonal variations observed in mercury deposition at Underhill were similar to those observed in the

Great Lakes basin (Hoyer et al. 1995, Burke et al. 1995). Concentration of particulate-associated

mercury in the air in 1993-94 tended to be greatest in winter months at this site. Concurrent monitoring

of mercury concentrations in stream water in a nearby forested catchment in the Lake Champlain basin

showed dissolved concentrations to be fairly constant, but found that total mercury (dissolved plus

particulate) was strongly correlated with flow rates. Thus, high flows may re-mobilize mercury adsorbed

to sediment and organic matter. Also, maximum stream flows were often associated with spring

snowmelt, which appears to be an important regulator of annual transport patterns of mercury within the

Lake Champlain basin (Scherbatskoy et al. 1999, 1998, 1997, Shanley et al. 1999). 

In another recent analysis, Pirrone et al. (1998) estimated atmospheric emissions and deposition

of mercury in North America and compared these estimates to vertical profiles of mercury accumulation

rates in sediment cores from four Great Lakes sites . The results of this analysis illustrate that
Chapter II

Environmental Progress

Page II-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

atmospheric deposition has been significant since the 1900s and still is the major contributor of mercury

to the Great Lakes, although a variety of other sources (including direct discharges) also contribute to

mercury inputs in the Great Lakes. Based on sediment core data and emissions estimates, Pirrone et al.

calculated the atmospheric deposition flux of mercury to North America as a whole to be between 14.3

and 19.8 μg/m2/yr (1.43 to 1.98 ng/cm2/yr), whereas in the Great Lakes region, the atmospheric

deposition flux of mercury was calculated to be higher, at 135 μg/m2/yr (13.5 ng/cm2/yr). This difference

is likely due to local anthropogenic emissions and subsequent deposition of mercury in the Great Lakes

region. Furthermore, mercury accumulation rates in sediment cores from the Great Lakes from preindustrial to modern times increased from 0.7 to 235 ng/cm2

/yr in Lake Ontario, from 0.8 to 65 ng/cm2/yr

in Lake Michigan, and from 3 to 175 ng/cm2/yr in Lake Erie. All of these values are larger than those

reported in sediment cores from small remote lakes in the northeastern U.S., indicating local and regional

sources of mercury are deposited in the Great Lakes region rather than simply from the regional

background in the northeastern U.S.

Engstrom and Swain (1997) analyzed sediment core data to detect recent trends in mercury

emissions in the upper Midwest and found that, for a number of Minnesota lakes, mercury deposition

peaked in the 1960s and 1970s and then declined. These declines were not seen in remote lakes in

southeastern Alaska, indicating that deposition from the global pool had not declined. The decline in

deposition inputs to Midwestern lakes can be attributed to reduced emissions from regional and local

sources, which are thought to be largely due to pollution controls (particularly on waste incinerators) and

a shift from coal to natural gas for residential and commercial heating.

Mass Balance Studies of Mercury

Preliminary results of the Lake Michigan Mass Balance Study (LMMBS; described in the

Second Great Waters Report to Congress) are becoming available. Results from two studies (Hurley et

al. 1998b, Landis 1998), which are discussed below, show varying results. The study by Hurley et al.

(1998b) involved sampling eleven tributaries that are representative of a variety of watersheds as part of

the LMMBS. For example, land-use patterns included agricultural, forest, wetland, and urban. Ten of

the 11 tributaries sampled are associated with areas of concern due to past contamination. Sediment core

and sediment trap analysis is still being conducted by EPA for the LMMBS samples; however, tributary

sample analysis has been completed. The mean mercury concentration in the 11 tributaries was 6.9 ng/L,

with the highest concentrations in the rivers running through the urban areas. The highest mean mercury

concentration (36.0 ng/L) was observed on the Fox River running through Green Bay, while the lowest

mean concentration (1.0 ng/L) was observed on the Muskegon River. In general, the northern rivers had

lower tributary inputs than the more industrialized southern rivers.

Hurley et al. (1998b) calculated tributary loading to Lake Michigan from each river as the

product of the daily average water discharge and the daily mercury concentration. The estimated annual

tributary mercury flux was 230 kg/year. The total annual mercury input into Lake Michigan from the

atmosphere and the tributaries during the LMMBS was estimated to be 1,419 kg/year. Atmospheric

deposition was determined to be the dominant source of mercury inputs to Lake Michigan, contributing

approximately 84 percent (1,189 kg/year) of the annual total. 

The study by Landis (1998) involved a hybrid-modeling framework based on monitoring data in

the Great Lakes region. Annual deposition estimates from Landis (1998) are provided in Table II-2. In

addition, the Landis modeling effort indicated that the Chicago/Gary urban area was responsible for at

least 19 percent of the total atmospheric deposition to Lake Michigan. It should be noted that reactive

mercury deposition is not included in this estimate of the urban influence and, thus, likely represents an

underestimate of the true impact of the Chicago/Gary urban area. 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-13

Table II-2

Preliminary Estimates of Total Atmospheric Mercury Deposition to Lake Michigan

Deposition Annual Total (kg) Annual Mean (μg/m2)

Wet 614 ± 186 10.6 ± 3.2

Aerosol Dry 69 ± 38 1.2 ± 0.7

Reactive Gaseous Mercurya 506 8.8

Dissolved Gaseous Mercuryb-460 -8.0

Total 729 12.6

a

 Reactive gaseous mercury (RGM) deposition values do not include error bars because they

reflect a sensitivity analysis performed on a single measurement in place of direct measurements

since no measurement method was available for RGM at the time of the study.

b Dissolved gaseous mercury (DGM) deposition values do not include error bars because the

values reflect a single measurement taken to establish modeling parameters.

Source: Landis 1998

In another effort, Hurley et al. (1998a) collected and analyzed field samples from the Fox River

in Wisconsin, which is located in a highly industrialized area and feeds into Green Bay, and ultimately,

Lake Michigan. While total mercury in this river is high relative to other tributaries feeding into Lake

Michigan, most of the mercury is bound to sediments. In the Fox River, resuspended sediments appear to

be the predominant source of mercury into Green Bay. However, in the Lower Fox River and Green Bay,

methylmercury concentrations are relatively low, suggesting that particulate-bound mercury has limited

bioavailability (Hurley et al. 1998a).

As part of the Chesapeake Bay Atmospheric Deposition Study (CBADS), mercury wet

deposition, dry deposition, and gas exchange were measured at sampling sites in the Chesapeake Bay

representative of regional background levels. Total atmospheric deposition of mercury to the

Chesapeake Bay was estimated to be 80 kg/year. Wet deposition of mercury to the Chesapeake Bay

surface waters was estimated to be 162.1 kg/year (± 10-20 percent). Dry deposition was estimated to be

32.4 kg/year (accurate within a factor of two or three). Gas exchange was a net output that was estimated

to be -115 kg/year (± 40 percent). Note that to develop these estimates, it was assumed that 10 percent of

the surface waters below the fall line (see Figure II-5) are impacted by urban deposition and that the

loading estimates are sensitive to this assumed percentage value (Chesapeake Bay Program 1999a).

Several additional mass balance studies are ongoing in Lake Michigan, Long Island Sound, and

the Chesapeake Bay to characterize mercury inputs to as well as losses from these systems (Table II-3). 

In Long Island Sound, Fitzgerald (1998) collected and analyzed precipitation, air, surface water, and

biota samples to develop a mass balance for mercury. In the Chesapeake Bay, Mason et al. (1997)

developed a mercury mass balance based on precipitation, throughfall, and stream water samples. The

mass balance study of Lake Michigan by Mason and Sullivan (1997) is a smaller effort than the LMMBS

and is primarily a mass-balance modeling exercise based on data extracted through a literature review.

Similarities among the various mass balance studies include the finding that atmospheric

deposition is a pathway with enough relative contribution in these waters to be of consideration (e.g.,

from 10 to greater than 80 percent). Furthermore, several of these studies indicate that air-water

exchange (through net volatilization) and sediment burial are two major loss pathways.
Chapter II

Environmental Progress

Page II-14 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table II-3

Mercury Sources Identified in Mass Balance Studies

 (by percent contribution)

Location

Atmospheric

Deposition

(%)

Urban Area

(%) Riverine Groundwater

Direct

Discharge Comments

Lake

Michigan a

~ 80 ~ 30

(Chicago)

~17 < 1 Not

reported

Air-water exchange

and sediment burial

account for the major

loss pathways from

the lake, but

atmospheric

deposition dominates

inputs

Chesapeake

Bay b

> 50 

(Wet 47-53)

(Dry 9-11)

Baltimore

(percent not

known)

~33-49 Not

reported

Not

reported

Over 90 percent of the

mercury entering the

watershed is retained

in the terrestrial

system and does not

reach the aquatic

system

Long Island

Sound c

~10 New York

New Jersey

(percent not

known)

~ 52 Not

reported

~ 36 Tidal exchange,

sediment burial, and

air-water exchange

are major loss

pathways. 45 percent

of the mercury

entering the Sound is

re-emitted

a Mason and Sullivan (1997).

b Mason et al. (1997).

c Fitzgerald (1998).

Factors Affecting Mercury Fate and Transport in Watersheds and

Tributaries

Recent research illustrates that a number of factors influence whether mercury that is deposited

to watersheds or tributaries will be transported to the lake itself. The principal factors that affect mercury

loading to the aquatic ecosystem appear to be (1) the amount of annual precipitation; (2) the influence of

the urban air plume (in terms of local deposition of the contaminated plume); (3) storms and other events,

like snowmelt, which influence stream flow and the resuspension of particle-bound mercury in

sediments; and, (4) prevailing land use (e.g., forestry, agriculture, urban). Some of these factors appear

to influence the amount of mercury in throughfall (i.e., precipitation that has washed through the forest

canopy) and litterfall (i.e., fallen leaves) as well as the amount of mercury that is sequestered in organic

soils which prevent its transport through the watershed.

Rea et al. (1996) found that throughfall and litterfall are the dominant components of mercury

deposition in forested areas of the Lake Champlain basin. Monitoring during a 6-week period in August

and September 1994 produced estimates of annual throughfall and litterfall deposition of 11.7 μg/m2/yr

and 13 μg/m2/yr, respectively. Thus, the total below-canopy deposition rate was estimated to be 24.7

μg/m2/yr, considerably greater than the 15.1 μg/m2/yr wet plus dry deposition estimated by Scherbatskoy
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-15

et al. (1997). In the former study, precipitation deposition accounted for just 32 percent (or 7.9 μg/m2/yr)

of this estimated below-canopy deposition.

 Several recent studies related to mercury cycling in the Lake Champlain basin, which focused

primarily on forested systems, suggest that urban and agricultural systems may retain less atmospheric

mercury than forested systems. For example, an analysis of mercury deposition and stream export (i.e.,

transport of mercury out of the basin through streamflow) in an 11 hectare, deciduous forested catchment

(i.e., a portion of the larger watershed) in the Lake Champlain basin based on field sampling showed net

annual stream export of mercury was less than 10 percent of wet deposition. Consistent with an earlier

study in the basin, stream export was strongly related to flow and dominated by mercury in particulate

form (i.e., mercury complexed with organic material). In 1 year of the study, fully one-half of the total

annual export occurred on the single day of peak snowmelt. A more recent stream water sampling and

deposition monitoring study also showed that most of the mercury transported in stream water is in the

particulate phase, with the dissolved phase contributing only about 30 percent of the annual export. 

Analysis of soil water mercury reported in this study suggested that the transport of dissolved mercury in

shallow soil water may be the primary mechanism for mercury movement from the forest floor to

streams. These studies showed that the forested catchment is a net sink for atmospheric mercury and

indicated that forests in the Lake Champlain basin help reduce the movement of mercury to the lake

because the mercury is bound to soil organic matter. Some portion of the mercury is mobilized, however,

and undergoes three possible fates: transport to streams through groundwater and overland (flood) flow,

incorporation into vegetation by root uptake, or volatilization back to the atmospheric pool (Scherbatskoy

et al. 1998, 1997, Shanley et al. 1999) . 

Mercury Exposure and Effects

Once deposited, mercury may enter terrestrial and aquatic food chains. Mercury concentrations

increase at successively higher levels in the food chain such that predators at the top of these food chains

are potentially at risk from consumption of mercury in contaminated prey. Of the various forms of

mercury in the environment, methylmercury has the highest potential for bioaccumulation in the food

chain. In the Mercury Study Report to Congress, the Agency concluded that fish-eating birds and

mammals are particularly at risk from mercury emissions and exposures. Ecosystems most at risk from

airborne releases of mercury exhibit one or more of the following characteristics:

C Located in areas where atmospheric deposition of mercury is high;

C Include surface waters that are already impacted by acid deposition;

C Possess characteristics other than low pH (e.g., high organic content, long aquatic food chains)

that result in high levels of bioaccumulation; and/or,

C Include sensitive species (U.S. EPA 1997e).

Although a large body of research exists on mercury exposure and effects, as discussed below

and in previous Great Waters Reports to Congress, areas of uncertainty remain, particularly with respect

to mercury methylation processes and their implications for exposure levels. The EPA and others are

currently planning and conducting research projects to address the fate and transport of mercury

compounds and subsequent exposures to methylmercury. Some examples of research under way related

to methylmercury include investigations of the following:
Chapter II

Environmental Progress

Page II-16 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

• The role of a variety of biogeochemical parameters in watersheds, wetlands, and marine

environments on mercury bioavailability, bioconcentration, and methylation;

• The effects of anthropogenic ecosystem changes on methylation rates, such as increased sulfate

deposition, increased nutrient loads, and increased loadings of mercury due to soil disturbance;

• The role of sulfur (especially sulfide) in mercury methylation in watersheds as related to

microbial activity; and

• The effects of agricultural sulfur on methylmercury in soils and wetland areas.

Effects of mercury can be two-fold. First, mercury in lower-level organisms can impact the

health of those organisms. Next, these organisms become prey for higher-level organisms, resulting in

higher-level organisms having higher concentrations of mercury than the lower-level organisms. 

Concentrations of methylmercury in fish tissue have been measured at levels one million times greater

than the mercury concentration in the surrounding water column, illustrating the extent to which

methylmercury can be concentrated in organisms. 

Principal factors affecting the bioavailability of mercury in the waterbody include (1) whether it

is bound to organic matter (which would inhibit bioavailability); and, (2) characteristics of the lake itself,

such as surface area to volume ratio (with more shallow lakes having more bioavailable mercury). When

conditions in a waterbody change (i.e., pH), the bioavailability of a compound can change without a

change in the concentration of the compound. 

Analyzing sediments for mercury concentrations can reveal the extent to which bottom dwelling

organisms are exposed. Eskin et al. (1996) compiled and analyzed sediment contamination data from the

Chesapeake Bay and its tributaries from 1984 to 1991. The potential for sediment contamination to

impact aquatic life was evaluated by comparing median and maximum contaminant concentrations to no

observed effects levels (NOELs) for aquatic biota, probable effects levels (PELs) for aquatic biota, or

other aquatic health benchmarks. The NOELs are concentrations above which impacts on aquatic life are

judged to be possible. Aquatic life impacts are considered probable at concentrations above the PELs. 

For toxic effects to occur, metals must not only be present at concentrations above aquatic life

benchmarks, but must also be bioavailable. 

Where data were available for comparison, sediment mercury concentrations in the Chesapeake

Bay, in general, were lower in 1991 than in previous years. The median and maximum concentrations of

mercury at all locations in the mainstem of Chesapeake Bay were 0.08 and 0.8 ppm, respectively, which

are below the mercury PEL of 1.4 ppm for aquatic biota. However, because maximum concentrations of

mercury in all segments of the bay exceeded the mercury NOEL of 0.1 ppm for aquatic biota, adverse

impacts are still possible. The median and maximum mercury concentrations in tributaries were 0.1 and

4.66 ppm, respectively. Mercury concentrations were highest in the Middle River, other northwestern

tributaries, and near the Sewells Point Naval Complex on the James River. Median mercury

concentrations exceeded the mercury NOEL for aquatic biota in several tributaries, including the James

and Potomac Rivers. The PEL concentration for mercury was exceeded only in the James River at

stations near the Sewells Point Naval Complex.

Sources with episodic emissions or releases of mercury and other pollutants to the Delaware Bay

influence concentrations in biota. Horseshoe crab eggs are of particular importance for monitoring

efforts because they are a major food source for many species of migrating shore birds during the spring

migration. While measurements of mercury levels in the eggs of horseshoe crabs from Delaware Bay,
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-17

New Jersey in 1993, 1994, and 1995 do not indicate any temporal trend, levels of mercury varied

markedly among years, with the highest values in 1994 (Burger 1997). The variations in mercury levels

and the peak in 1994 highlights the importance of episodic sources of pollutants to the Delaware Bay,

which is situated downstream from highly industrialized areas in Trenton, New Jersey; Wilmington,

Delaware; and, Philadelphia, Pennsylvania. Burger (1997) also analyzed mercury concentrations in

female horseshoe crab leg muscle tissues from the Delaware Bay and found that mercury concentrations

were higher in leg muscle tissues than in eggs and were indicative of few adverse effects to developing

horseshoe crabs.

In an evaluation of higher level organisms, Brazner and DeVita (1998) detected mercury in

yellow perch and spottail shiners from 23 sites in Green Bay, Lake Michigan. The overall distribution of

mercury tissue concentrations was fairly uniform within the bay, indicating that mercury contamination

originates primarily from non-point sources, including atmospheric deposition. Certain sites exhibited

unusually high mercury residues in fish, however, suggesting these sites may be associated with direct

discharges of mercury nearby. The mercury residue levels of 9.4 to 31.0 ng/g in yellow perch and 10.5 to

33.5 ng/g in spottail shiners were well below the International Joint Commission Aquatic Life Guideline

for total mercury of 500 ng/g. Furthermore, these mercury levels were similar to or below the most

recently reported (i.e., 1993, 1985) mercury levels in fish in most of the locations in the Great Lakes. 

Mercury levels apparently decreased in yellow perch taken from the St. Lawrence River, which

drains the Great Lakes, in 1991-1992 and were compared to results from a 1975 study (Ion et al. 1997). 

Mercury was detected in all yellow perch samples taken from various sites along the river. Comparison

of average mercury concentrations to historical levels in St. Lawrence River fish indicates a two- to

three-fold decrease since 1975. Because mercury contamination and bioaccumulation can vary

considerably from site to site and species to species, additional studies of this type are needed for trends

analysis of mercury levels in fish.

Fish-eating birds are of particular interest for evaluating the effects of mercury because relative

to their body weight, exposures can be very high. Hughes et al. (1997) detected significant differences in

mercury concentrations in both osprey eggs and chick feathers from nests at four Great Lakes study areas

in Ontario (three natural lakes and one reservoir) and two Delaware Bay sites in New Jersey. Overall,

eggs from the Ogoki Reservoir and chick feathers from St. Mary’s River (Ontario) and the Ogoki

Reservoir had significantly higher mercury concentrations than the eggs and feathers sampled from the

other locations. Despite these geographic variations, mercury levels in osprey eggs, chick feathers, and

adult feathers at all locations were below the levels associated with toxic reproductive effects, such as

reduced number of eggs, decreased hatchability, increased hatchling mortality, and altered reproductive

behavior. Fish sampled at each site also exhibited significant differences in mercury levels with a clear

spatial pattern, similar to that observed for chick feathers. However, the study did not assess the relative

impact of point source discharges and atmospheric deposition on spatial variation. 

In a recent study that attempted to link spatial variations in mercury levels in biota with

variations in atmospheric deposition of mercury, Evers et al. (1998a) found that mercury concentrations

in the feathers and blood of adult and juvenile common loons from sites within five regions across North

America (Canadian Maritimes, New England, Upper Great Lakes, northwestern U.S., and Alaska)

increased significantly from western regions to eastern regions. Adults had average blood mercury levels

which were 10 times higher than juveniles. Feather mercury levels increased significantly over a 4-year

period, probably due to bioaccumulation of mercury over that time period. At some of the study

locations where exposure is high (e.g., some eastern North American locations), the loon’s natural

mechanisms to excrete excess mercury (e.g., feathers, eggs, demethylation and storage in the liver and

kidney) may not be sufficient to balance current exposure levels. The researchers note that the observed
Chapter II

Environmental Progress

Page II-18 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

geographical gradient agrees with EPA’s Regional Environmental Monitoring and Assessment Program

(R-EMAP) modeling of atmospheric deposition of mercury and predicted high impact areas (U.S. EPA

1997e) and the Northeast States and Eastern Canadian Provinces Mercury Study (NESCAUM 1998). 

Within the upper Great Lakes region (nine sites total), blood mercury levels were influenced the most by

lake biogeochemistry and hydrology, rather than atmospheric deposition. Significantly higher

concentrations from sites in north-central Wisconsin and central Ontario were detected. The authors

conclude that loons breeding on low-pH lakes in the upper Great Lakes and in all lake types in

northeastern North America are the most at risk from mercury contamination. A comparison of the

measured blood mercury concentrations to health threshold levels determined from laboratory studies

indicate that 12 to 31 percent of New England’s breeding loon population exceed these levels (Evers

1998b). Based on feather mercury levels, over 30 percent of the male loons exceed threshold levels for

health effects. 

Like wildlife, fish consumption represents the dominant pathway for human exposure to

methylmercury. Given the current scientific understanding of the environmental fate and transport of this

element, it is not possible to quantify how much of the methylmercury in fish consumed by the U.S.

population is contributed by U.S. emissions relative to other sources of mercury (such as natural sources

and re-emissions from the global pool). As a result, it cannot be assumed that a change in total mercury

emissions will be linearly related to any resulting change in methylmercury in fish, nor over what time

period these changes would occur. This is an area of ongoing study. 

The effects of methylmercury on humans and especially the developing fetus are well known and

have been described in detail in earlier Reports to Congress. The critical target for methylmercury

toxicity for humans is the nervous system. The factors that affect whether the mercury exposure is

sufficient to cause health effects depend primarily on the species of fish consumed, the concentration of

methylmercury in the fish, the quantity of fish consumed, and how frequently fish is eaten. The 1997

EPA Mercury Study Report to Congress includes a detailed analysis of potential public health impacts

relating to fish consumption. This analysis was based on information on the mercury levels in various

types of fish, dietary surveys, and EPA’s current reference dose (RfD) for methylmercury. The RfD is an

estimated daily ingestion level anticipated to be without adverse effect to persons, including sensitive

subpopulations, over a lifetime. Note that the National Academy of Science is currently reviewing more

recent mercury health effects studies and will recommend whether the EPA should revise its RfD for

methylmercury. This review and recommendation is expected to be completed by mid-2000.

The Mercury Study report concluded that the typical U.S. consumer eating fish from restaurants

and grocery stores was not in danger of consuming harmful levels of methylmercury from fish and is not

advised to limit fish consumption on the basis of mercury content. However, eating more fish than is

typical or eating fish that are more contaminated than typical fish can change the advice. Because the

developing fetus is regarded as the most sensitive to the effects of methylmercury, women of

child-bearing age are the population of greatest concern. 

 

In addition, for cultural or economic reasons, some people in certain ethnic groups (e.g., Asians,

Pacific Islanders, Native Americans) and subsistence fishers eat substantially more fish than the average

consumer. Because of the higher amounts of fish in their diets, people in these groups, especially the

women of child-bearing age, need to be aware of how much mercury is in the fish they consume. The

Mercury Study report has more detailed information about amounts of mercury found in various types of

fish. 

The Food and Drug Administration (FDA) and State, local, and tribal agencies issue advisories

that suggest limiting the consumption of contaminated fish. Mercury fish advisories in the U.S. have been
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-19

issued by 40 States and some tribes. Eleven States have Statewide advisories for mercury in freshwater

lakes or rivers, and five States have Statewide advisories for mercury in coastal waters. Based on data

from December 1997, 20 of 56 Great Waters are associated with mercury fish consumption advisories

(U.S. EPA 1998m). The EPA is sponsoring work with the State of Wisconsin to assess current methods

of communicating fish consumption advisories and to recommend improvements.

Despite this advice, a recent survey on awareness and effectiveness of fish advisories found that

only half of the Great Lakes sport fish consumers were aware of health advisories related to fish

consumption (Tilden et al. 1997). While one study of Lake Ontario anglers concluded that the angler

subpopulation’s health does not significantly differ from those experienced by the general North

American population (Cole et al. 1997), a different study concluded that the consumption of

contaminated fish affected time-to-pregnancy (i.e., the amount of time between when a women plans to

become pregnant and the date of pregnancy). The study also found that 42 percent of the women

surveyed reported consumption of contaminated fish from Lake Ontario, despite highly publicized

advisories against the consumption of fish from Lake Ontario by women of reproductive age (Buck et al.

1997).

According to Tilden et al. (1997), the most widely accepted advisory recommendation was

cleaning and cooking methods. While cooking methods are effective to reduce PCB exposure, mercury

concentrations will actually increase, on a per weight basis, with all cooking methods (including pan

frying, deep-frying, baking, boiling, and smoking) because of the moisture and fat lost during cooking

(Morgan et al. 1997). Unlike PCBs which accumulate in fatty tissue that can be removed prior to

consumption, mercury accumulates in the muscle tissue or filet portion. 

Studies of mercury exposure in U.S. populations are limited, particularly for the general

population. However, research is being planned as part of EPA’s draft Mercury Research Strategy (see

Chapter III) to address this need. A number of studies have been conducted involving sport fisherman

and Native peoples, which have shown high levels of fish consumption in a number of populations; but,

risk of exposure is dependent, in large part, on the level of contamination in the fish (U.S. EPA 1997e). 

A recent study of Ojibwa tribal members from the Great Lakes region indicates that mercury

concentrations in Ojibwa populations are low; however, researchers identified several individuals with

elevated levels of mercury (Gerstenberger et al. 1997).

OTHER METALS (LEAD AND CADMIUM)

Sources and Emissions of Lead and Cadmium

Lead and cadmium are naturally-occurring trace metals and, therefore, are expected to be

detected at some background level in the environment, depending on the location. Furthermore, because

lead and cadmium are metals, they are by nature persistent compounds that may cycle between

environmental compartments. Therefore, while it is possible to estimate lead and cadmium emissions

from anthropogenic sources, it is difficult to determine which sources (e.g., specific human-made

sources, natural sources, cycling) contribute to total and atmospheric deposition inputs to the Great

Waters.

Based on a study of lead, cadmium, and other trace metals emissions and air concentrations in

the Great Lakes region from 1982 to 1993, (1) sources of lead in 1993 included steel manufacturing, coal

combustion, non-ferrous metal production, and waste disposal (Figure II-3), and (2) sources of cadmium
Chapter II

Environmental Progress

Page II-20 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

HIGHLIGHTS

Other Metals (Lead and Cadmium)

' Sources. In some urban locations, local sources (versus

regional sources) are primarily responsible for atmospheric

deposition of lead and cadmium to the Great Lakes, whereas the

opposite is true in some more remote locations. The largest

national sources of lead air emissions are mobile sources, including

non-road vehicles and equipment (aircraft) and on-road vehicles. 

Emissions and ambient air concentrations of lead have continued to

decrease since the 1970s. The largest national sources of

cadmium air emissions include secondary lead smelting, primary

copper smelting, and primary lead production. Cadmium air

emissions increased from 1982 to 1988 in the Great Lakes region

and have not shown a trend since 1988.

' Loadings. In the Great Lakes region, lead deposition 

decreased from 1988 to 1994, and cadmium deposition may have

decreased from 1992 to 1994. In the Chesapeake Bay, 

atmospheric deposition of cadmium and lead contributes no more

than 5 to 7 percent, respectively, to total loadings. Total inputs from

all pathways of lead and cadmium increased in the eastern section

of the bay from 1966 to 1995 due to the increase in human

population and industrial activities. However, trends in the relative

contribution of atmospheric deposition of lead and cadmium to the

Chesapeake Bay have not been discerned. In the Long Island

Sound, lead inputs have been decreasing since 1980 and

atmospheric deposition contributes 70-90 percent of total lead

inputs.

' Environmental Concentrations. Sediment contamination

studies in the Chesapeake Bay provide conflicting results – one

study found increased lead and cadmium levels, possibly due to an

increase in population, industrial activities, and agricultural activities,

whereas another found decreasing levels. Lead and cadmium

levels in Chesapeake Bay sediments, in general, were between the

aquatic biota NOEL and PEL; however, bioavailability of these

metals is low. In the Delaware Bay, lead levels decreased in

horseshoe crab eggs in recent years, but cadmium levels were

more variable.

in 1993 included coal combustion,

solid waste and sewage sludge

incineration, iron-steel

manufacturing, non-ferrous metals

production, and several smaller

sources (Figure II-5) (Pirrone and

Keeler 1996). 

A review of cadmium and

lead emission sources on a national

scale, based on EPA’s National

Toxics Inventory for the time period

from 1990-1993 (1990-1993 NTI),

provides a somewhat different

picture compared to regional

sources for the Great Lakes (Tables

II-4 and II-5). The larger nationallevel sources of lead air emissions

are mobile sources, including nonroad vehicles and equipment

(aircraft) and on-road vehicles. The

larger national-level sources of

cadmium air emissions are

secondary lead smelting, primary

copper smelting, and primary lead

production (U.S. EPA 1999a). The

NTI data for lead air emissions also

indicate that there are many source

categories that are emitting similar

amounts of lead compounds, rather

than there being a few source

categories contributing the majority

of the air emissions. The

differences observed between the

local (Figures II-3 and II-5) and

national (Tables II-4 and II-5) source characterizations for these pollutants highlight the importance of

examining both local sources and regional sources, as well as the need to consider the influence of urban

areas on nearby waterbodies. 

A study of lead emissions and air concentrations indicates that, overall, U.S. lead emissions have

decreased since the 1970s, primarily due to the phaseout of leaded gas. Lead emissions in the Great

Lakes region decreased steadily from 1982 to 1993 at a rate of about 6.4 percent per year. Lead

emissions in the Great Lakes region in 1988 were estimated to be 4,430 tpy. Lead concentrations in

ambient air also showed steady declines over the entire region between 1982 and 1993. The regional

decrease in lead emissions and air concentrations is correlated to the reduction of lead in gasoline (from

0.28 g/l in 1982 to 0.026 g/l in 1989) and an increase in unleaded gasoline use in both the U.S. and

Canada since 1981. Sources of lead emissions also shifted over this time period. As shown in Figures II3 and II-4, about 80 percent of lead emissions were from leaded gasoline use in 1982 compared to 1993

when most lead emissions were from four major industrial sources in the Great Lakes region (Pirrone and

Keeler 1996). Another study of lead deposition to sediments in Central Park Lake in New York City
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-21

using sediment cores indicates, however, that municipal solid waste incineration contributed a large

portion of the lead deposited during the same time period that lead from leaded gasoline was deposited. 

Furthermore, lead emissions from municipal solid waste incinerators decreased beginning in 1966 due to

progressive facility closures following regulations. Therefore, although it is clear that lead emissions and

deposition have decreased, it is possible that solid waste incineration has been underestimated as a source

of atmospheric lead in the past, particularly to urban areas (Chillrud et al. 1999).

In contrast to lead emissions and ambient air concentrations, cadmium emissions in the Great

Lakes region increased from 1982 to 1988 at a rate of 5.2 percent per year, with a peak in 1988 at 150

tpy. Since 1988, emissions of cadmium have not increased or declined (Pirrone and Keeler 1996).

Deposition of Lead and Cadmium

Data collected under the Integrated Atmospheric Deposition Network (IADN), a joint U.S.-

Canada program that monitors pollutant levels in air and precipitation at remote sites in the Great Lakes

region, by Eisenreich and Strachan in 1992 and Hoff et al. in 1994 show that total deposition of lead

decreased from 1988 to 1994 in each of the Great Lakes. Paode et al. (1998) found that measured

average lead fluxes in Chicago, Illinois were 0.07 mg/m2/day, whereas over Lake Michigan, lead fluxes

were 0.003 mg/m2/day, demonstrating the urban influence of Chicago on atmospheric deposition of lead

onto Lake Michigan. Dry deposition of cadmium in the Great Lakes region decreased from 1992 to

1994; however, this decrease may be due to improved averages in the particulate air concentrations of the

metals (Hoff et al. 1996). Sweet et al. (1998) estimated annual wet and dry deposition rates to Lake

Michigan, Lake Erie, and Lake Superior using air and rain concentrations of lead and cadmium measured

at three U.S. IADN sites and found that lead and cadmium deposition levels were similar at all lakes. 

Since the IADN sites are situated in remote locations, this finding indicates regional atmospheric

deposition, rather than local emissions, is the source of lead and cadmium at the remote sites on these

three lakes. 

Estimates of total inputs of trace metals to the Chesapeake Bay indicate that inputs of trace

metals from the non-tidal watershed are much higher than trace metal inputs to tidal waters from point

source discharges, urban storm water inputs, and direct atmospheric deposition to the tidal waters. The

boundary for the non-tidal and tidal waters in the Chesapeake Bay region is indicated in Figure II-6. 

Inputs from the non-tidal watershed to the Chesapeake Bay consist of all point and non-point

sources, including atmospheric deposition. Atmospheric deposition (measured as direct deposition to

water surfaces based on monitoring data) of cadmium and lead contributes approximately 4.6 and 5.6

percent, respectively, to total inputs to the Chesapeake Bay (Table II-6). Note that these percentages may

be underestimates because the monitoring site locations do not reflect the urban influences of Baltimore,

Maryland on the Chesapeake Bay. However, these percentages are similar to those for other metals but

are much less than percentages for polycyclic aromatic hydrocarbon (Eskin et al. 1996).
Chapter II

Environmental Progress

Page II-22 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-3

1993 Lead Emissions in the Great Lakes Region

(Pirrone and Keeler 1996)

Figure II-4

1982 Lead Emissions in the Great Lakes Region

(Pirrone and Keeler 1996)
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-23

Figure II-5

1993 Cadmium Sources in the Great Lakes Region

(Pirrone and Keeler 1996)

Table II-4

National Anthropogenic Lead Air Emissions 

(Based on EPA’s 1990-1993 National Toxics Inventory)

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution

to Total U.S.

Anthropogenic Air

Emissions

Mobile sources: non-road vehicles and equipment - aircraft 619 18.7

Mobile Sources: on- road vehicles 418 12.6

Primary lead 259 7.8

Steel wire and related products manufacturing 163 4.9

Mobile sources: non-road vehicles and equipment - other 158 4.8

Primary copper smelting 152 4.6

Pulp and paper: combustion 150 4.5

Lead oxide in pigments 136 4.1

Secondary lead smelting 106 3.2
Chapter II

Environmental Progress

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution

to Total U.S.

Anthropogenic Air

Emissions

Page II-24 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Municipal waste combustion 80 2.4

Non-stainless steel manufacture - EAF 79 2.4

Utility boilers: coal combustion, all types 72 2.2

Secondary copper smelting 71 2.2

Medical waste incineration 63 1.9

Hazardous waste incineration 56 1.7

Secondary nonferrous metals production 55 1.7

Pressed and blown glass and glassware manufacturing 52 1.6

Storage batteries manufacturing 51 1.5

Portland cement manufacture: hazardous waste-fired 41 1.2

Primary nonferrous metals production 40 1.2

Paint application: no spray booth 35 1.1

Others (< 1 percent each) a 454 13.7

Total U.S. Anthropogenic Lead Air Emissions 3,310b 100b

a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in Appendix B.

b

 This value represents anthropogenic lead air emissions in the U.S. only.

Source: U.S. EPA 1999a
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-25

Table II-5

National Anthropogenic Cadmium Air Emissions 

(Based on EPA’s 1990-1993 National Toxics Inventory)

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution

to Total U.S.

Anthropogenic Air

Emissions

Secondary lead smelting 84 42.2

Primary copper smelting 16 8.1

Primary lead 16 7.9

Hazardous waste incineration 9 4.3

Petroleum refining: catalytic cracking units 7 3.3

Municipal waste combustion 5 2.5

Medical waste incineration 5 2.4

Cadmium refining and cadmium oxide production 5 2.3

Secondary copper smelting 5 2.3

Industrial inorganic chemical manufacturing 4 2.2

Sewage sludge incineration 4 1.9

Cadmium stabilizers production 4 1.8

Pulp and paper: combustion 3 1.7

Portland cement manufacture: hazardous waste-fired 2 1.2

Inorganic pigments: cadmium pigments in plastics 2 1.1

Primary nonferrous metals production 2 1.0

Others (<1 percent each) a 28 13.8

Total U.S. Anthropogenic Cadmium Air Emissions 201b 100b

a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in Appendix B.

b

 This value represents anthropogenic cadmium air emissions in the U.S. only.

Source: U.S. EPA 1999a
Chapter II

Environmental Progress

Page II-26 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-6

Chesapeake Bay Tidal and Non-tidal Waters

(Tributary basins are shaded)

Note: Fall line is the upper boundary of the tidal waters of the Chesapeake Bay.

Source: Chesapeake Bay Program 1994

Table II-6

Trace Metal Inputs to the Chesapeake Bay (kg/year)

Trace

Metal

Total Inputs to

Chesapeake

Baya

Direct 

Atmospheric

Deposition to

Tidal Waters

Direct Atmospheric

Deposition to Tidal

Waters as Percent of

Total Inputs

Cadmium 27,800 1,200 ~4.6

Lead 275,300 14,500 ~5.6

a

 Includes inputs from the non-tidal watershed (including atmospheric

deposition to the watershed), storm water inputs to the tidal waters, point

source inputs to the tidal waters, and direct atmospheric deposition to the

tidal waters. 

Source: Eskin et al. 1996
Chapter II

Environmental Progress

1

 CBADS measurements include wet deposition, dry deposition, and gas exchange of pollutants at rural

sites, with estimations for urban areas.

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-27

Data collected by the Chesapeake Bay Atmospheric Deposition Study (CBADS),1 as presented in

the Chesapeake Bay Program’s 1999 Toxics Loading and Release Inventory (TLRI), result in estimates of

total inputs to the Chesapeake Bay for cadmium and lead (42,600 and 254,000 kg/year, respectively) that

are similar to the Eskin et al. (1996) values. Inputs of lead and cadmium via atmospheric deposition to

the tidal waters of the Chesapeake Bay as a percentage of the total inputs are 7 percent and 3 percent,

respectively. Inputs from the non-tidal watershed dominate for lead and cadmium (Chesapeake Bay

Program 1999a, 1994). 

A study on the eastern shore of the Chesapeake Bay in Maryland using sediment cores found that

lead deposition rates range from 0.32 ± 0.20 to 13.60 ± 0.98 mg/m3/yr, and cadmium deposition rates

range from 0.01 ± 0.01 to 0.43 ± 0.04 mg/m3/yr. Total inputs of both lead and cadmium from all

pathways increased from 1966 to 1995 due to the increase in human population and industrial activities

(Karuppiah and Gupta 1998). 

Direct atmospheric deposition rates of lead and cadmium to the Massachusetts Bay based on

monitoring data are presented in Table II-7. In general, deposition of lead and most other metals is

higher at the monitoring site closer to Boston due to higher urban area emissions. However, deposition

of cadmium is similar at both the urban and rural locations. While there is not a seasonal trend for trace

metal deposition in general, higher dry deposition of lead has been observed in the winter (Golomb et al.

1997a). 

Table II-7

Direct Atmospheric Deposition of Lead and Cadmium 

to Massachusetts Bay (μg/m2/yr)

Trace Metal Urban Rural

Cadmium 260 280

Lead 2,300 1,400

Total 2,560 1,680

 Source: Golomb et al.1997a

In Long Island Sound, sediment cores from salt marshes indicate that lead inputs reached a

maximum between 1970 and 1980 at approximately 62 μg/cm2/yr and have been decreasing since that

time at most sites. Atmospheric deposition to the water surface of Long Island Sound contributes

approximately 90 percent of total lead inputs. At sites closer to New York City, cores show that

atmospheric deposition accounts for approximately 70 percent of lead inputs, suggesting that nonatmospheric sources (e.g., direct discharges, storm water runoff) play a larger role near the urban areas

(Cochran et al. 1998). 
Chapter II

Environmental Progress

Page II-28 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Seasonal Variation in Cadmium Concentrations

A monitoring study of the St. Lawrence River, which connects

the Great Lakes with the Atlantic Ocean, emphasized the

importance of seasonal variation on the concentration and

distribution of metals. Quémerais and Lum (1997) collected

water from sites in the river and four of its tributaries from

March to November 1991 and April to June 1992 and analyzed

the samples for dissolved and particulate cadmium. The mean

dissolved cadmium concentration for the basin (10 ± 5 ng/L)

was in the same range as that measured for rivers considered

pristine environments. The mean particulate cadmium

concentration (1.3 ± 1.1 μg/g) was also relatively low in

comparison to other waterbodies. Dissolved cadmium

concentrations exhibited a seasonal trend; concentrations

increased in spring and autumn and decreased in summer. 

The trend was attributed to increased runoff and leaching from

soil during spring snowmelt and rainfall events in autumn as

well as uptake by surface water microorganisms during

summer. The seasonal variation of particulate cadmium was

not as apparent, probably due to the negative influence of

suspended particulate matter, which is higher in spring and

autumn as a result of snowmelt and rainfall patterns.

Lead and Cadmium Levels in the Environment

Lead and cadmium levels have been measured in a variety of environmental media and in a wide

range of geographic locations in the Great Waters. The concentrations that are observed in the

environment are a result of atmospheric deposition from both domestic and international sources as well

as from non-atmospheric sources, including storm water runoff and direct discharges to waterbodies and

tributaries.

A recent study in the

Chesapeake Bay found an increase in

lead and cadmium concentrations in 

and toxicity of the sediments and pore

water (i.e., interstitial water of

sediments) of two tributaries

(Wicomico River and Pocomoke River)

in comparing sediment cores from

1966-1975 to sediment cores from

1986-1995 (Table II-8). The authors

examined the historical land use of

areas adjacent to these rivers and

concluded that the increases were likely

due to a variety of pathways. 

Specifically, (1) increases in metal

concentrations in Wicomico River

sediments and pore water are probably

due to an increase in population,

industrial activities, and the volume of

the sewage treatment plant influent; (2)

increases in metal concentrations in

Pocomoke River sediments and pore water are probably due to the increased runoff from agricultural

areas, including poultry farms; and, (3) increases in lead concentrations in Wicomico River sediments

and pore water are possibly due to an increase in various industrial activities, commercial facilities that

use lead compounds, and atmospheric deposition (Karuppiah and Gupta 1998). 

Other studies have found that sediment concentrations of lead and cadmium are declining,

however. Sediment concentration data from the Chesapeake Bay Program from 1984 to 1991, for

example, indicate that lead and cadmium concentrations in sediments are declining in some areas of the

Chesapeake Bay (Eskin et al. 1996). 

An analysis of spatial trends shows that metals concentrations in sediments of the mainstem of

the bay were lowest at the head of the bay and in the extreme lower bay. The highest metals

concentrations were detected in sediments of the segment of the bay closest to Baltimore, the largest

urban center on the bay. Lead contamination trends were somewhat different when concentrations were

normalized by the fine particle content of the sediment. In particular, normalized sediment

concentrations of lead gradually declined toward the mouth of the bay, suggesting that the Susquehanna

River is the primary source of lead. Lead concentrations were highest in the Middle River, other

northwestern tributaries, and near the Sewells Point Naval Complex on the James River. The distribution

of cadmium contamination was different from other contaminants, where the highest concentrations were

located in the sediments of the James (near the Sewells Point Naval Complex) and Patuxent Rivers and in

some of the southeastern tributaries (Eskin et al. 1996). 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-29

Table II-8

Temporal Changes in Metal Concentrations in Chesapeake Bay Tributaries

Based on Sediment Cores

Sediment

Core Depth

(cm)

Estimated

Period

(year)

Lead Cadmium

Sediment

(mg/kg)

Pore Water

(mg/L)

Sediment

(mg/kg)

Pore Water

(mg/L)

Wicomico River

0-7.5 1986-1995 18.01 5.12 0.49 0.026

7.5-15.0 1976-1985 7.60 0.54 0.48 0.008

15.0-23.0 1966-1975 7.43 0.42 0.37 0.007

Pocomoke River

0-7.5 1986-1995 5.14 0.74 0.28 0.025

7.5-15.0 1976-1985 3.51 0.59 0.24 0.003

15.0-23.0 1966-1975 2.35 0.59 0.20 0.002

 Source: Karuppiah and Gupta 1998

The potential for sediment contamination to impact aquatic life was evaluated by comparing

median and maximum sediment contaminant concentrations to aquatic health benchmarks in both the

mainstem of the Chesapeake Bay and its tributaries (Table II-9). Maximum concentrations of cadmium

and lead in the mainstem of Chesapeake Bay were below PEL concentrations for aquatic biota. 

However, impacts must be considered possible because maximum lead and cadmium concentrations

exceeded the aquatic biota NOEL in most of the upper half of the bay and at the mouth of the Potomac

River (Eskin et al. 1996).

In the Chesapeake Bay tributaries, median and maximum lead concentrations in sediments were

31 and 343 parts per million (ppm), respectively. Median lead sediment concentrations exceeded the

lead NOEL in northwestern tributaries, but the aquatic biota PEL for lead was exceeded only near the

Sewells Point Naval Complex. The median and maximum cadmium sediment concentrations were 0.6

and 6.0 ppm, respectively. The distribution of cadmium contamination was different from other

contaminants, where the highest concentrations were located in the James (near the Sewells Point Naval

Complex) and Patuxent Rivers and in some of the southeastern tributaries. Median cadmium sediment

concentrations in several of the western and northwestern tributaries exceeded the aquatic biota NOEL;

however, the maximum concentrations did not exceed the PEL for aquatic biota (Eskin et al. 1996).

For toxic effects to be possible, metals must not only be present at concentrations above aquatic

life benchmarks but must also be bioavailable (i.e., available for uptake by organisms). For instance, a

portion of the lead in sediments must not be bound to the organic matter in the sediment, and the lead

levels in the sediment must exceed the aquatic life benchmark in order for toxic effects to occur. Eskin et

al. (1996) found low bioavailability through most of the mainstem of the bay. However, bioavailable

conditions were found in a northern reach of the bay from Turkey Point to Annapolis. This reach

includes the most contaminated segment of the bay, between Baltimore and Annapolis (Eskin et al.

1996).
Chapter II

Environmental Progress

Page II-30 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table II-9

Cadmium and Lead in Sediments of the Chesapeake Bay Mainstem

Contaminant

Concentration Aquatic Life

Benchmark Location of Maximum

Concentrations Trends

Median

(ppm)

Maximum

(ppm)

NOELa

(ppm)

PELb

(ppm)

Cadmium 0.4 2.9 1.0 7.5

Baltimore region south to

the Little Choptank River;

mouth of Potomac River

Concentrations

are declining

Lead 35 86 21 160

Baltimore region Concentrations

are declining in

some areas

 a No Observed Effect Level. Level above which impacts are considered “possible.”

 b Probable Effect Level. Level above which impacts are considered “probable.”

 Source: Eskin et al. 1996

In the Delaware Bay, one study attributed decreases in lead levels in horseshoe crab eggs to a

general lowering of pollutants to the bay. Horseshoe crab eggs provide a bioindicator of pollutant levels

in the Delaware Bay because they are laid beneath the sand at the bay’s high tide line and are

continuously inundated with water. Burger (1997) measured levels of lead and cadmium in the eggs and

leg muscles of horseshoe crabs in 1993, 1994, and 1995 in the Delaware Bay and found a decrease in

lead levels in horseshoe crabs from 1993 to 1995. Cadmium levels in the eggs were significantly higher

in 1994 than in 1993 or 1995 (Table II-10). The variations in cadmium levels may suggest an episodic

source of cadmium to the bay, which is probable given the high level of upstream industrialization in

Trenton, New Jersey; Wilmington, Delaware; and, Philadelphia, Pennsylvania. Burger (1997) also

analyzed lead and cadmium levels in female horseshoe crab leg muscle tissues from the Delaware Bay

and found that lead and cadmium levels in leg muscle tissues were lower than in eggs and were indicative

of few adverse effects.

Table II-10

Lead and Cadmium in Horseshoe Crab Eggs from Delaware Bay

Year Lead (ppb) Cadmium (ppb)

1993 558 (±160) 17 (±5)

1994 206 (±34) 310 (±130)

1995 87 (±8) 24 (±7)

 Source: Burger 1997
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-31

HIGHLIGHTS

Dioxins and Furans

' Sources. The largest sources of dioxin and furan

emissions in the U.S. are municipal waste

combustion and medical waste incineration. By

2002, controls applied to these sources will reduce

their dioxin and furan emissions by 95-99 percent

(see Chapter III).

' Loadings. In the Great Lakes region, sediment

accumulation rates indicate a decline in dioxin and

furan inputs since the 1970s. The relative

atmospheric contribution and sediment accumulation

rates of dioxins and furans entering the Great Lakes

differs both between and within the lakes. In some

lakes, the atmospheric contribution of dioxins and

furans is 100 percent, whereas in other lakes, the

atmospheric contribution of dioxins and furans is less

than 5 percent. In general, the pattern of

industrialization around the lakes influences relative

contributions and accumulation rates.

' Concentrations in Biota. In general, long-term

monitoring data indicate that dioxin and furan

concentrations in biota in many Great Waters have

declined over time. 

COMBUSTION EMISSIONS

Dioxins and Furans

Polychlorinated dibenzo-p-dioxins

(PCDDs; dioxins) and polychlorinated

dibenzofurans (PCDF; furans) are compounds that

are similar in structure but differ in the number

and position of chlorine atoms. Much of the

current research uses toxic equivalent quantities

(TEQs) to express quantities of dioxins and

furans. The TEQs aggregate all of the dioxin and

furan congeners into a single factor that is

weighted by toxicity of the individual congeners

based on ratios to 2,3,7,8-tetrachlorodibenzo-pdioxin (2,3,7,8-TCDD) and to 2,3,7,8-

tetrachlorodibenzofuran (2,3,7,8-TCDF). 

Therefore, dioxin and furan quantities are

commonly expressed as dioxin TEQs and furan

TEQs, respectively. This is the convention

followed in this report to the extent permitted by

the research results reported in the literature.

Dioxins and furans are byproducts of

combustion that enter the environment primarily as a result of waste incineration and, to a lesser extent,

various manufacturing processes, but also through natural combustion processes. Different sources emit

different dioxin and furan compounds in certain combinations. These combinations, or source profiles,

can then be used to identify the source of the emissions. One such study developed a chemical mass

balance model to determine the contribution of different types of sources to sediment levels in the

Housatonic River in Connecticut, Lake Huron, and the Baltic Sea. The study found that air particulate

matter, coal-fired power plants, municipal incinerators, and pentachlorophenols (from manufacturing)

were, in general, the largest sources of dioxins and furans in sediments. The same study reported that

coal-burning was the major source of dioxins and furans prior to 1955 in the U.S. and 1970 in Europe,

with municipal incinerators dominating after that time (Su and Christensen 1997). These results are

similar to recent EPA estimates of national air emissions and sources of dioxin and furan TEQs which

indicate that of the 0.0027 tpy of dioxin and furan TEQ air emissions, municipal waste combustion

accounts for 47 percent and medical waste incineration accounts for 24.6 percent (Table II-11). A large

number of smaller sources also emit dioxins and furans (U.S. EPA 1999a). 

Emissions data for the U.S. and Canada were used with NOAA’s hybrid single particle

Lagrangian integrated trajectory (HYSPLIT)/transfer coefficient (TRANSCO) computer program to

analyze dioxin and furan sources and their contributions to atmospheric deposition of dioxins and furans

in the Great Lakes. For any given lake, the simulation results indicated that approximately half of the

atmospheric deposition of dioxins and furans arose from sources in the immediately surrounding States

and provinces, and half arose from the remainder of the U.S. and Canada. Furthermore, the relative

contribution of sources by class were ranked, showing that municipal waste incineration, iron sintering,

cement kilns burning hazardous waste, and medical waste incineration are responsible for at least 85

percent of the total atmospheric deposition of dioxins and furans to the Great Lakes. This study also
Chapter II

Environmental Progress

Page II-32 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

found that sources of dioxins as far away as central Canada may influence deposition of dioxins to the

Great Lakes (Cohen et al. 1995).

Table II-11

National Anthropogenic Dioxin and Furan TEQ Air Emissions 

(Based on EPA’s 1990-1993 National Toxics Inventory)

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution to

Total U.S. Anthropogenic

Air Emissions

Municipal waste combustion 0.0012 47.0

Medical waste incineration 0.0007 24.6

Secondary aluminum smelting 0.0002 7.2

Utility boilers: coal combustion, all types 0.0001 4.2

Industrial boilers: wood/wood residue combustion 0.00009 3.4

Mobile sources: on-road vehicles 0.00009 3.4

Open burning: wildfires and prescribed burnings 0.00009 3.4

Portland cement, excluding hazardous waste-fired 0.00004 1.5

Residential wood/wood residue combustion 0.00004 1.5

Wood treatment/wood preserving 0.00003 1.1

Others (< 1 percent each) a 0.00007 2.6

Total U.S. Anthropogenic Dioxin and Furan TEQ Air

Emissions 0.0027b 100b

 a A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in 

 Appendix B.

 

b

 This value represents anthropogenic dioxin and furan TEQ air emissions in the U.S. only.

 Source: U.S. EPA 1999a

Sediment core studies have also been used to determine the relative atmospheric contribution of

dioxins and furans. One sediment core study indicates that the relative atmospheric contribution of

dioxins and furans differs by lake based on comparisons of pollutant compositions and accumulation

rates among cores to estimates of atmospheric deposition (Table II-12). In the Great Lakes region,

accumulation rates of dioxins and furans in sediments began to increase in the early 1940s. Maximum

accumulation rates were observed in 1970 ± 10 years, and current accumulation rates are 30 to 70 percent

of the maximum levels (Pearson et al. 1997a). Current accumulation rates of dioxins and furans in

sediments indicate inter- and intra-lake variations. For example, the current dominant source of dioxins

and furans in Lake Superior is believed to be the atmosphere because sediment accumulation rates of

dioxins and furans are similar to those of lakes in which the atmosphere is the only possible source of

dioxins and furans. In southern Lake Michigan near the Chicago urban area, the atmosphere contributes

most of the dioxins in the lake, but 65 to 95 percent of furans entering southern Lake Michigan are

estimated to be from non-atmospheric sources. In northern Lake Michigan, the analysis of sediment

cores indicates that approximately 50 percent of dioxins and greater than 75 percent of furans are from

non-atmospheric sources. From 65 to 95 percent of dioxins and greater than 95 percent of the furans
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-33

accumulated in Lake Ontario are estimated to be from non-atmospheric sources based on the analysis of

sediment cores (Pearson et al. 1998). 

Table II-12

Current Rates of Dioxins and Furans Accumulation in Great Lakes Sediments

Location

Number of

Sediment Cores

Analyzed

Accumulation Rates in Sediment

(pg/cm2/yr)

Percent Contribution from

Atmospheric Sources

Dioxins a Furans a Dioxins a Furans a

Lake Superior 2 7.4 - 8.0 0.8 - 0.9 100 100

Northern Lake

Michigan 2 44 - 49 22 - 25 33 - 55 5 - 35

Southern Lake

Michigan near

Chicago Urban

Area

1 17 17 100 5 - 35

Lake Ontario 3 120 - 220 130 - 230 5 - 35 <5

 

a

 Includes the total of all dioxin homologs. Includes the total of all furan homologs.

 Source: Pearson et al. 1998

To help explain and understand the inter- and intra-lake variations in loadings and accumulations

of dioxins and furans, the HYSPLIT/TRANSCO computer program was used to estimate the amount of

dioxin and furan emitted from identified sources to air and water that enter the five Great Lakes (Cohen

et al. 1995). The model was run using 1993 source and emissions data from 1,329 identified sources in

the U.S. and Canada. As shown in Table II-13, the modeled deposition flux of dioxins and furans

increases from Lake Superior, Lake Huron, Lake Michigan, Lake Erie, to Lake Ontario, following the

pattern of industrialization around the lakes. In addition, modeled waterborne inputs (i.e., direct

discharges) of dioxins and furans to Lake Superior, Lake Michigan, and Lake Huron play a lesser role

than air deposition. For Lake Michigan, these relative source findings are different from those found by

Pearson et al. (1998) who used a sediment core methodology to estimate relative atmospheric

contributions. In Lake Erie and Lake Ontario, the modeled waterborne inputs are uncertain because of

the difficulty in quantifying discharges to and from inter-lake channels (Cohen et al. 1995).

Table II-13

Modeled Air Deposition, Depositional Flux, and Waterborne Inputs

of Dioxins and Furans to the Great Lakes

Dioxins and Furans Superior Huron Michigan Erie Ontario Total

Atmospheric Deposition (g TEQ/yr)

(range)

5.6

(2-17)

8.6

(3-25)

13.7

(5-43)

7.3

(2-21)

6.4

(2-18)

42

(13-124)

Depositional Flux (μg/km2/yr) 69 145 238 284 337 172

Waterborne Inputs (g TEQ/yr) 1.4 1.4 1.9 11 >3.9 >19.6

Percent Contribution from

Atmospheric Sources 80 86 88 40 ~62 ~68

Source: Cohen et al. 1995
Chapter II

Environmental Progress

2

 The abbreviation, POM, is also used by ecologists, limnologists, and oceanographers for Particulate

Organic Matter.

Page II-34 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

HIGHLIGHTS

 Polycyclic Organic Matter

' Sources. Nationally, the largest source of PAHs 

is consumer products usage, along with many smaller

emission sources. Studies in the Great Lakes region also

indicate that vehicular emissions, coal-fired power plants,

and coke and steel production are large sources of PAH

emissions. Note that multiple conventions are used to

report POM and PAH quantities because of the differences

in health effects of the variety of POM and PAH

compounds.

' Loadings. In general, PAH deposition levels follow the 

pattern of population density and urbanization. In the Great

Lakes region, maximum sediment accumulation levels of

PAHs occurred between 1950 and 1975, after which

accumulation levels declined. Data from recent years in the

region, however, do not indicate a clear trend. In the

Chesapeake Bay, data indicate that total loadings for

several PAH compounds decreased in recent years, but

data collection methodologies were altered over the same

time period, making it difficult to assess the true trend.

' Environmental Concentrations. Concentrations of

PAHs in the sediments of tributaries and mainstem of the

Chesapeake Bay are below the aquatic biota probable

effects level (PEL), but are above the no observed effect

level (NOEL) for aquatic biota in the northern bay. In the

tributaries, PAH sediment concentrations declined

substantially between 1987 and 1991. 

Biota in many Great Waters are contaminated with dioxins and furans (Firestone et al. 1996,

Metcalfe et al. 1997a, 1997b, Wade et al. 1997b). Recent studies of contamination of biota in the Great

Waters implicate non-atmospheric sources of dioxins (Firestone et al. 1996, Wade et al. 1997b) and

furans (Wade et al. 1997b); however, the relative importance of atmospheric sources and nonatmospheric sources remains unclear. In many instances, long-term monitoring indicates that

concentrations of dioxins and furans have declined over time. For example, the U.S. Food and Drug

Administration monitored the presence of dioxin in the edible portions of fish and shellfish from major

U.S. waterways from 1979 to 1994, and the analytical results indicate that levels in aquatic species from

most waterways are declining steadily (Firestone et al. 1996). In several locations (e.g., Chesapeake Bay,

Delaware Bay, Gulf of Mexico, and Galveston Bay), no dioxin was found in fish samples taken between

1987 and 1994. In addition, Huestis et al. (1997) reported that levels of dioxins and furans in Lake

Ontario trout collected from 1977 to 1993 have declined substantially, although most chemical levels

appear to have reached a steady state or are declining more slowly now.

Polycyclic Organic Matter

Polycyclic organic matter (POM2),

like dioxins and furans, is a byproduct of

fossil fuel combustion and natural

combustion processes (e.g., forest fires),

and consists of a group of compounds with

similar chemical structures. The POM

compounds are emitted in distinct patterns

from various source types, allowing the

identification of emission sources from

emission “fingerprints” (or patterns) in

contaminated sediments. Within this class

of POM are the polycyclic aromatic

hydrocarbons (PAHs). In most cases,

human-made sources of PAHs account for

the majority of PAHs released to the

environment (Simcik et al. 1996). These

compounds are usually the POMs of

concern as many PAHs are known or

suspected human carcinogens. Therefore,

the discussion of POMs focuses on PAHs.

There is not one standard

convention to measure and express

emissions and quantities of POM. 

Multiple conventions have been developed

because of the differences in the health

effects of the variety of POM and PAH compounds. Some of the measures that are used include 16-PAH

(i.e., the 16 PAH compounds that can be measured using EPA test method 610), 7-PAH (i.e., the seven

PAH compounds that are probable carcinogens), or extractable organic matter (EOM) (i.e., the solvent
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-35

extractable portion of organic matter). These conventions, however, are not necessarily followed by

independent researchers and thus are not always used in this report. 

Based on EPA’s 1990-1993 national inventory of air emissions, the dominant 16-PAH emission

source is consumer products usage (e.g., metal cleaning, solvents, household cleaning products, and

personal care products), along with many other smaller emission sources (Table II-14) (U.S. EPA 1999a).

Table II-14

National Anthropogenic 16-PAH Air Emissions 

(Based on EPA’s 1990-1993 National Toxics Inventory)

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution to

Total U.S. Anthropogenic

Air Emissions

Consumer products usage 5,733 33.2

Open burning: wildfires and prescribed burnings 2,540 14.7

Aerospace industry (surface coating) 1,697 9.8

Petroleum refining: other sources not distinctly listed 783 4.5

Primary aluminum production (from ESD) 662 3.8

Pulp and paper: kraft recovery furnaces 649 3.8

Coke ovens: charging, topside, & door leaks 538 3.1

Coke ovens: pushing, quenching, and battery stacks 517 3.0

MON - continuous processes 440 2.5

Gasoline distribution stage II 374 2.2

Gasoline distribution stage I 355 2.1

Petroleum refining: catalytic cracking units 313 1.8

Open burning: scrap tires 294 1.7

Industrial Organic chemicals manufacturing 227 1.3

Pulp and paper: lime kilns 183 1.1

Others (< 1 percent each) a 1,967 11.4

Total U.S. Anthropogenic 16-PAH Air Emissions 17,271b 100b

a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in Appendix B.

b

 This value represents anthropogenic 16-PAH air emissions in the U.S. only.

Source: U.S. EPA 1999a

In the Great Lakes and other waterbodies, several researchers analyzed sediment cores to identify

spatial and temporal trends in PAH deposition and sources, as discussed below. Researchers estimated

relative contaminant contributions from specific local human-made sources (e.g., smelters, coke ovens)

along with regional sources (e.g., fuel oil combustion, wood burning). In general, recent sediment core
Chapter II

Environmental Progress

Page II-36 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

studies show regional deposition from oil and wood burning sources with significant contributions from

local sources in industrialized areas.

In Lake Michigan sediments, PAHs originate primarily from vehicular emissions; wood, oil, and

natural gas burning for home heating; coal-fired power plants; and, coke and steel production. A study

by Simcik et al. (1996) that focused on the urban complex of Chicago, Illinois and Gary, Indiana

concluded that the dominant source of PAHs to the entire lake from around 1900 to the present is

emissions from coke and steel production. This conclusion differs from that of Karls and Christensen

(1998) who found a regional historical pattern in central Lake Michigan, with a significant contribution

from wood-burning and an increasing dominance of oil-burning sources (as opposed to coal-burning by

coke and steel production), which is consistent with U.S. fuel consumption data. Karls and Christensen

also found that PAH loadings at Green Bay, the Fox River, and the Kinnickinnic River were strongly

influenced by local industrial activities, primarily coke production at the Milwaukee Solvay Coke

Company which operated from 1900 to the 1970s. These differing conclusions support the finding that

local urban sources of PAHs are different and often play a larger role in deposition and sediment

accumulation than regional sources.

Other studies also indicate that urban sources largely influence PAH deposition. For instance,

recent sediment layers in the Milwaukee Harbor area indicate that in urban areas, highway dust can be a

significant source of PAHs from emissions of gasoline engine exhaust tar (Christensen et al. 1997). In a

carbon particle sediment core study, the relative abundance of oil particles in sediments increased in

recent years and is explained by an increase in automobile traffic (Karls and Christensen 1998). Sharma

et al. (1997) found that source contributions of PAHs to the St. Mary’s River (which connects Lake

Superior and Lake Huron) were strongly influenced by traffic density and urban storm water runoff from

impervious street surfaces.

These recent findings for PAHs follow the pattern that was illustrated for several other pollutants

of concern: 

C Local point sources and regional sources both play a role in the deposition of pollutants to

waterbodies; 

C Urban areas play a strong role whether through the proximity of industrialized areas to

waterbodies or through urban runoff; and, 

C The relative contribution to pollutant loadings by different types of emission sources shifts over

time depending on industrial activities, pollution controls, and other factors such as trends in fuel

use. 

 

Lake Michigan sediment cores show that PAH accumulation began between 1880-1900,

consistent with increased PAH emissions from coal combustion during industrialization. Maximum PAH

accumulation occurred between 1950-1975 (Simcik et al. 1996). Karls and Christensen (1998) found

similar results. Maximum accumulation rates were lower in the southern basin near the Chicago urban

area (70 ng/cm2/yr) than in the northern basin (100-150 ng/cm2/yr) because of the south to north transport

of sediment-bound PAHs. One study observed a slight decrease in PAH sediment accumulation rates in

recent years in some cases due to a switch from coal to oil and natural gas and because of industrial

emissions controls (Simcik et al. 1996). In contrast, recent deposition monitoring data from the IADN

program do not indicate any clear trend in total atmospheric loadings of PAHs, as indicated by data for

benzo[a]pyrene (B[a]P), to the Great Lakes from 1988 to 1996 (Figure II-7). Trends in PAH deposition
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-37

levels, in general, are difficult to discern because of (1) the degree of uncertainty in loading calculations

and (2) the fluctuations in ambient air concentrations (U.S. EPA 1998l).

Figure II-7

IADN Loading Estimates of B(a)P to the Great Lakes (kg/year)

(U.S. EPA 1998i)

As part of the Lake Michigan Mass Balance Study (LMMBS) and the Atmospheric Exchange

Over Lakes and Ocean Surfaces (AEOLOS) study, which examine the influence of urban air emissions

on deposition to the Great Waters, Franz et al. (1998) found that dry deposition of PAHs to Lake

Michigan contributes approximately 5,000 kg/year. Wet deposition estimates from previous studies are

lower at approximately 1,600 kg/year. Franz et al. (1998) also found that dry deposition of PAHs is

higher in Chicago than 15 km offshore and at rural sites because of (1) the greater degree of

anthropogenic activity within the Chicago area, and (2) the greater atmospheric burden and subsequent

deposition of large particles generated within that area. These findings are consistent with the hypothesis

that larger particles are generated in urban areas and are deposited closer to the sources than smaller

particles. 

In the Massachusetts Bay, as in other regions, the sum of wet and dry deposition of PAHs is

greater at monitoring sites in urban areas (i.e., closer to Boston and Logan Airport) than at monitoring

sites in rural areas (i.e., Truro), with the exception of biphenyl and naphthalenes (Table II-15). Biphenyl

and naphthalenes may be more likely to deposit at the rural site because these pollutants are more water

soluble and, therefore, may be deposited as wet deposition from clouds carrying biphenyl and

naphthalenes from other geographic areas. Deposition of PAHs in this region is highest in the winter,

possibly due to increased use of fossil fuels during winter for residential and commercial heating and
Chapter II

Environmental Progress

Page II-38 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

wood burning in stoves and fireplaces, or due to the lower mixing heights in the atmosphere which occur

during winter in North America (Golomb et al. 1997b). 

Table II-15

Sum of Wet and Dry Deposition of PAHs onto Massachusetts Bay (μg/m2/year)

PAH Urban Rural

Acenaphthene 5.0 1.8

Acenaphthylene 5.2 3.3

Anthracene 9.5 3.7

Benzo[ghi]perylene 29.2 4.1

Biphenyl 4.3 7.7

Chrysenes 98.8 9.9

Dibenzothiphenes 34.8 13.2

Fluoranthene 129.0 23.9

Fluorenes 50.0 23.0

Naphthalenes 206.6 240.0

Perylene 11.5 3.2

Phenanthrenes 215.1 41.9

Pyrenes 97.8 16.9

 Source: Golomb et al. 1997b

In the Chesapeake Bay, estimates from one study of total inputs and atmospheric inputs of PAHs

indicate that direct atmospheric deposition to the tidal waters of the Chesapeake Bay range from 30

percent to 56 percent (Table II-16). Estimates of the relative atmospheric contribution for

benzo[a]anthracene and chrysene may be slightly high because estimates were not provided for point

sources of benzo[a]anthracene and non-tidal watershed inputs for chrysene. Highest loadings occur in

the West Chesapeake and Potomac regions. Intermediate loadings occur in the James and Patuxent

regions, and lowest loadings occur in the Rappahannock, York, and eastern shore regions (Eskin et al.

1996). Annual net inputs (in terms of atmospheric deposition processes and the largest source of riverine

inputs) of nine PAH compounds to the Chesapeake Bay are provided in Table II-17 based on sampling

and analysis of surface water and air. In general, gas phase absorption (i.e., absorption of pollutants in

the gas phase in the atmosphere by the water surface) of PAHs is higher than estimates of wet and dry

deposition loadings; however, wet and dry deposition become more important loading factors for higher

molecular weight PAHs (Nelson et al. 1998).

In contrast, the analysis of CBADS monitoring data in the Chesapeake Bay Program’s 1999

Toxics Loading Release and Inventory (TLRI) provides additional and more recent information on total

inputs and relative atmospheric deposition inputs of PAHs (including benzo[a]pyrene, chrysene,

phenanthrene, and pyrene) to the tidal and non-tidal portions of the Chesapeake Bay (see Figure II-6 for

the delineation of the tidal and non-tidal waters in the Chesapeake Bay watershed). Total inputs to the

tidal waters of the Chesapeake Bay of benzo[a]pyrene, chrysene, phenanthrene, and pyrene are estimated

to be 29,000 kg/year, 29,000 kg/year, 59,000 kg/year, and 40,000 kg/year, respectively. Total

atmospheric deposition (wet, dry, and gas exchange) ranges from < 0.5 percent (35 kg/year) for
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-39

benzo[a]pyrene to 5 percent (2,900 kg/year) for phenanthrene. Inputs of PAHs from the non-tidal

watershed account for less than 3 percent of the total PAH inputs to the Chesapeake Bay (Chesapeake

Bay Program 1999a).

Table II-16

Estimates of PAH Inputs to the Chesapeake Bay (kg/year)

PAH

Total Inputs to

Chesapeake

Bay

Direct Atmospheric

Deposition to Tidal

Waters

Direct Atmospheric

Deposition to Tidal Waters

as Percent of Total Inputs

Benzo[a]anthracene 380 130 34

Benzo[a]pyrene 430 130 30

Chrysene 570 320 56

Fluoranthene 1,300 640 49

Naphthalene 1,500 NE NE

 NE = no estimate

 Source: Eskin et al. 1996

Table II-17

Annual PAH Inputs to and Losses from the Chesapeake Bay

PAH

Annual Inputs and Losses (kg/year)

Susquehanna

River a

Wet

deposition

Dry aerosol

depositionb

Net gas deposition 

(or volatilization)c

Fluorene 122 16 12 379

Phenanthrene 450 63 92 2875

Anthracene NA 6 6 130

2-Methylphenanthrene NA NA NA 702

1-Methylphenanthrene NA NA NA 280

Fluoranthene 1130 70 120 679

Pyrenes 1030 75 109 361

Benz[a]anthracene 376 9 34 (4.6)

Chrysene 330 29 85 29

 a The Susquehanna River is the largest source of freshwater to the Chesapeake Bay.

 b Calculated from measured ambient aerosol particle contaminant concentrations and annual average dry aerosol 

 deposition velocity of 0.49 cm/s.

 c Values in parentheses represent net volatilization from rather than net deposition to the waterbody.

 Source: Nelson et al. 1998

In a study to quantify the gaseous exchange fluxes across the air-water interface at rural, semiurban, urban, and industrialized sites of the southern Chesapeake Bay, researchers found that aerosol

particle-associated PAH concentrations measured in the atmosphere were similar at the four sites and

PAH gas-phase concentrations measured in the atmosphere were as much as 50 times greater at the urban

site than at the rural site. Furthermore, at the rural site (Haven Beach, VA), PAH gas-phase
Chapter II

Environmental Progress

Page II-40 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

concentrations in the atmosphere are decreasing with time. Specifically, in 1991, the PAH gas-phase

concentration was 6,203 pg/m3 whereas in 1994-1995, PAH gas-phase concentrations were only 4,550

pg/m3. This study also analyzed seasonal variations and did not find any seasonal variations in PAH gasphase concentrations at this site. At the non-rural sites, an exponential increase in PAH gas-phase

concentrations was observed with temperature increases, indicating that PAHs volatilize from

contaminated surfaces near these sites in warmer weather (Gustafson and Dickhut 1997). 

In a sediment contamination study of the Chesapeake Bay and its tributaries from 1984 to 1991

by Eskin et al. (1996), PAHs were most concentrated in sediments of the northern bay between Turkey

Point and the mouth of the Middle River, just north of Baltimore. Maximum PAH concentrations in

sediments (14,854 ppm) at all locations in the bay were below the aquatic biota PEL for total PAHs of

28,000 ppm. However, maximum concentrations exceeded the NOEL of 2,900 ppm for aquatic biota

over much of the northern bay north of Annapolis. In the Chesapeake Bay tributaries, PAHs were most

abundant in sediments of the western, northwestern, and northeastern tributaries. The highest

concentrations were located in the Sassafras River. However, concentrations in sediments in tributaries

declined dramatically between 1987 and 1991. Median PAH sediment concentrations in tributaries

rarely exceeded aquatic biota NOELs and never exceeded aquatic biota PELs. Thus, toxic effects from

PAH sediment contamination are possible in the northern part of the mainstem bay, but are not likely in

the tributaries. 

NITROGEN AND COMPOUNDS

Nitrogen is an ubiquitous element in the natural environment and is essential to all forms of life. 

It is a component of protein and genetic material and plays a key role in photosynthesis. Nitrogen cycles

through all terrestrial and aquatic ecosystems and in many systems is a primary factor determining the

nature, diversity, and productivity of the ecosystems. Diatomic nitrogen gas (N2), an inert, largely

biologically inactive gas, comprises almost 78 percent of the earth’s atmosphere. Despite the presence

and essential nature of nitrogen throughout the natural environment, excessive levels of certain nitrogen

compounds in the atmosphere, deposited to surface media or introduced to aquatic systems, can be

detrimental to terrestrial and aquatic habitats and potentially to human health.

Nitrogen compounds are released to the atmosphere from a variety of sources, both natural and

anthropogenic. Nitrogen compounds can be present in the atmosphere in a variety of inorganic and

organic forms, in gaseous, liquid, or solid (particulate) states. Table II-18 identifies the most common

forms of atmospheric nitrogen and summarizes their key sources and properties. As this table indicates,

the most important forms of atmospheric nitrogen from the standpoint of atmospheric deposition and

loadings to surface waters include the following.

C Nitric Oxide and Nitrogen Dioxide (NO and NO2, or collectively NOx). Nitrogen oxide

compounds are the key forms of anthropogenic nitrogen released to the atmosphere and are

precursors to the formation of nitrogen compounds that are ultimately deposited to the Great

Waters. Most of the nitrogen emitted to the air from anthropogenic sources is in the form of

NOx, primarily NO. Once released to the atmosphere, NOx is transformed through a variety of

complex photochemical reactions to oxidized nitrogen compounds and, ultimately, aerosol nitrate

and nitric acid. These end products are deposited to the surface and impact surface waters. 

Nitrogen oxide also is a catalyst in the formation of ozone.
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-41

HIGHLIGHTS

Nitrogen Compounds

' Sources. Sources of anthropogenic nitrogen

emissions to air include on-road vehicles, fuel

combustion for electricity generation, farm animal

wastes, non-road vehicles and engines, fuel

combustion by industry, fertilizer application, biomass

burning, and miscellaneous other minor sources.

Anthropogenic nitrogen oxide (NOx) emissions rose

rapidly through the late 1970s. Nitrogen oxide

emissions have leveled off since around 1980, mainly

due to controls under the CAA. Nationwide trends in

emissions of other compounds cannot be determined

with available data. 

' Loadings. The rate of anthropogenic nitrogen

compound deposition from the air to the Great Waters

rose through the late 1970s, but has leveled off since

around 1980. Trends in atmospheric deposition

nitrogen (ADN) loading to the Great Waters are

uncertain, but have probably been static for the past

two decades. ADN loadings to various Great Waters

along the east coast account for roughly 10 percent to

40 percent of total nitrogen loadings. 

' Human and Ecological Effects. The effects of

ADN on the Great Waters is indistinguishable from the

effects of nitrogen from other sources. Anthropogenic

nitrogen loads to the Great Waters are currently many

times natural rates. Mechanisms for eliminating or

assimilating nitrogen are overwhelmed in many

waterbodies, leading to nitrogen buildup. Effects of

excess nitrogen include algal blooms, eutrophication,

anoxia, loss of species diversity, and fundamental

changes to ecosystem structure. These effects are

observed with increasing frequency and extent in many

of the Great Waters of the east and Gulf coasts. In

sufficient concentrations, some nitrogen compounds

have toxic effects on humans. However, nitrogen

compounds generally do not cause exceedances of

drinking water standards in the Great Waters.

C Nitric acid (HNO3), Aerosol Nitrate

(NO3), Ammonia and Ammonium

(NH3 and NH4

+

, or collectively NHx),

and Organic Nitrogen Compounds.

These are the nitrogen compounds that

are deposited from the atmosphere to

surface media and impact surface

waters. Reduced nitrogen compounds

(NHx) compounds (e.g., ammonia,

ammonium) also account for a

significant portion of nitrogen

emissions from anthropogenic (as well

as biogenic) sources.

Discussions of atmospheric nitrogen emissions,

deposition, and effects in this report focus on

these compounds. In particular, the term

“atmospheric nitrogen” hereafter refers to these

compounds and excludes N2, the inert, natural

component of the earth’s atmosphere.

Nitrogen Emissions and

Atmospheric Transport

In the natural environment, diatomic

nitrogen gas (N2) is converted to biologically

available forms of nitrogen (e.g., NOx,

ammonium compounds) through nitrogen

fixation processes such as lightning and

biological fixation. Nitrogen emissions from

lightning have been estimated at less than 10

million metric tons per year. Releases of fixed

nitrogen from marine ecosystems are less

certain and range from less than 30 to greater

than 300 million metric tons per year. Nitrogen

fixation in terrestrial ecosystems, prior to human influences, ranged from 90 to 140 million metric tons

per year; however, these emission levels have increased due to human alterations to the nitrogen cycle

(Vitousek et al. 1997).

Of the various forms of nitrogen emitted to the atmosphere through anthropogenic activities, only

NOx emissions have been quantified adequately to allow evaluation of nationwide emissions trends. 

Nationwide emissions of NOx generally reflect trends in population, economic activity, and

industrialization for most of this century. Nitrogen oxide emissions steadily increased in the first three

decades of the century, but declined in the 1930s due to the lower economic activity during the Great

Depression. With the start of World War II, NOx emissions nationwide began a rapid upward trend that

continued well into the 1970s. Between 1940 and 1970, total nationwide NOx emissions increased by a

factor of three, from 6.5 million to 19 million metric tons per year (U.S. EPA 1997f, U.S. EPA 1997h). 
Chapter II

Environmental Progress

Page II-42 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table II-18

Common Forms of Atmospheric Nitrogen

Compound Notation Sources State in the

Atmosphere Effects

Inert Compounds

Diatomic

nitrogen gas

N2 Comprises approximately

78 percent of the earth’s

atmosphere

Gaseous Inert; no direct effects.

Converted to other compounds

through certain biological and

physical processes

Nitrous oxide N2O Wide variety of natural

sources, fertilizer

production and use, fossil

fuel combustion, industrial

acid production, microbial

denitrification in soil and

water

Gaseous Not reactive in lower

atmosphere; potent greenhouse

gas, 320 times as effective as

CO2 in trapping heat in the

atmosphere

Oxidized Compounds

Nitric oxide NO Natural soil emissions,

lightning, combustion

processes with

temperatures greater than

2200 EC 

Gaseous Precursor in the formation of

NO2, nitrates, nitric acid, and

ozone in the atmosphere, and to

NO2, nitrate, and nitric acid

deposition 

Nitrogen dioxide NO2 Combustion processes with

temperatures greater than

2200 EC, atmospheric

oxidation of NO

Gaseous Highly reactive; a variety of

acute and chronic human health

effects; precursor or catalyst in

the formation of nitrates, nitric

acid, and ozone in the

atmosphere; deposits slowly to

surface media; precursor to

nitrate and nitric acid deposition

Aerosol nitrate NO3 Photochemical oxidation of

NOx (i.e., NO and NO2) in

the atmosphere;

combustion processes. 

Partitioning of HNO3 to the

aerosol phase by ammonia

gas in the atmosphere;

microbial oxidation of

ammonium in soil and water

Fine particles,

dissolved in

precipitation

Possible mutagen; variety of

adverse health effects

associated with fine particles;

deposits to surface media.

Excess NO3 in drinking water

has adverse health effects,

including methylglobinemia in

infants. Potent nutrient

stimulant of plant growth,

contributing to eutrophication in

waterbodies 

Nitric acid HNO3 Photochemical oxidation of

NOx in the atmosphere.

Vapor, liquid

aerosol,

dissolved in

precipitation

Deposits quickly to surface; is

the source of most oxidized 

nitrogen deposited to the

surface; causes surface water

acidification, property damage;

detrimental to aquatic biota and

ecological systems. Contributes

to NO3 concentrations and

related health effects in drinking

water. Potent nutrient stimulant

of plant growth, contributing to

eutrophication in waterbodies 
Chapter II

Environmental Progress

Compound Notation Sources State in the

Atmosphere Effects

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-43

Other oxides of

nitrogen

PAN,

N2O5,

others

Intermediate reservoir

products in atmospheric

chemical reactions forming

HNO3 from NOx

Gaseous Eye irritant; possible mutagen;

precursor or catalysts in

formation of ozone; PAN is an

important oxidant in the

atmosphere and a component of

photochemical smog 

Reduced Compounds (NHx)

Ammonia NH3 Volatilization from animal

wastes; natural microbial

decomposition of organic

matter in oceans and soils;

manufacture and

application of fertilizers;

hydrolysis of urea in

fertilized soils; biomass and

fossil fuel combustion

Gaseous,

vapor,

dissolved in

precipitation

Highly reactive; reacts to form 

NH4

+

, establishing an NH4

+

/NH3

equilibrium in the atmosphere. 

Deposits to the surface; potent

nutrient stimulant of plant

growth, contributing to

eutrophication in waterbodies

Ammonium NH4

+ Formed in the atmosphere

from reaction of NH3 with

atmospheric acids such as

H2SO4 and SO4, microbial

transformation of organic

nitrogen, microbial fixation

in soil and water

Particulate, 

dissolved in

precipitation

Can be transported long

distances; ultimately deposits to

the surface; with NH3

contributes as much as 20-40

percent of atmospheric nitrogen

deposition to coastal waters.

Potent nutrient stimulant of plant

growth, contributing to

eutrophication in waterbodies.

Organic Compounds

A wide variety

of compounds

of unknown

composition,

believed to

include urea,

pollen and,

amino acids

Various,

mostly

unknown

Primarily released from 

biological processes; also

released from

anthropogenic processes

and formed in the

atmosphere from chemical

and photochemical

reactions of NOx,

hydrocarbons, and O3

Various Comprises10-30 percent of

atmospheric nitrogen wet

deposition to coastal waters; 

contributes to eutrophication in

surface waters 

The 1970 CAA introduced significant regulation of NOx emissions. Various programs and rules

under the CAA regulate specific sources of NOx air emissions (a more detailed discussion of programs

affecting NOx emissions is presented in Chapter III). Nationwide NOx emissions continued to increase

and reached a peak in 1978, but declined slightly in 1979 and 1980 as more and more CAA NOx

programs began to take effect. Since 1980, the effects of increasing economic activity and the effects of

increasingly comprehensive regulation of NOx have roughly balanced out, and NOx emissions have been

relatively constant.

Figure II-8 shows the trend in national NOx emission rates from 1985 to 1996. As this figure

indicates, nationwide NOx emissions have fluctuated around 21 to 23 million metric tons per year

throughout this period. Nationwide NOx emissions in 1996 were 21.2 million metric tons (U.S. EPA

1997g). Figure II-9 presents 1996 NOx emissions by State (U.S. EPA 1997f).
Chapter II

Environmental Progress

Page II-44 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-10 presents relative NOx emissions from principal anthropogenic sources in 1996 on a

nationwide basis (U.S. EPA 1997f). The “all other” category includes miscellaneous minor sources such

as chemical and allied product manufacturing, storage, and transport; metals processing; petroleum and

related industrial processing; solvent utilization; other industrial processes; and, waste disposal and

recycling.

Reduced nitrogen (ammonium) compounds are also released from anthropogenic sources at rates

approaching those for NOx in some areas. Relative contributions of various anthropogenic nitrogen

sources to atmospheric nitrogen and nitrogen deposition vary from region to region depending on the

predominant economic activities of each region. Both North Carolina and the Chesapeake Bay region,

for example, have relatively high concentrations of animal farming operations, a key source of

ammonium compound emissions. For example, Aneja et al. (1998) determined that anthropogenic

emissions of ammonium compounds account for over 40 percent of anthropogenic nitrogen releases to air

in North Carolina (Figure II-11). Similarly, Fisher and Oppenheimer (1991) found that ammonia and

ammonium primarily released from crop and animal farming operations contributes 20 to 40 percent of

total atmospheric deposition nitrogen (ADN) to the Chesapeake Bay. However, additional research is

needed to better quantify ammonia and ammonium emissions to the environment. The EPA is

collaborating with the U.S. Department of Agriculture (USDA) and academia to develop emission factors

for various practices and to better model transport and deposition. 

A recent monitoring study of wet deposition of nitrogen in the Chesapeake Bay used stable

isotope analysis to identify sources. Results of the study indicate some seasonal trends. For example, in

the spring, a peak in ammonium was observed as a result of agricultural emissions, including fertilizers,

soil, animal excreta from the southwest and west regions of the bay. An observed peak in nitrate in the

spring indicates greater soil emission rates during the spring; however, the dominant source of nitrate in

the region is probably fossil fuel combustion primarily from the northwest and west regions of the bay. 

No seasonal trend was observed for dissolved organic nitrogen, but it is likely that it originates from

sources similar to nitrate sources (Russell et al. 1998).

Once emitted to the atmosphere, nitrogen compounds (particularly NOx) can travel great

distances – 600 to 800 kilometers or farther from the point of emission to the point of deposition (Dennis

1997). The airsheds of the Great Waters for nitrogen compounds (defined as the geographic region from

which atmospheric nitrogen deposited to the Great Waters originates) are, therefore, extensive and

collectively encompass much of the U.S. as well as parts of neighboring countries. Using the Regional

Atmospheric Deposition Model (RADM), Dennis (1997) determined that the NOx airshed for the

Chesapeake Bay watershed encompasses roughly 900,000 square kilometers, including all or part of 15

States and two Canadian provinces, extending into Indiana to the west, South Carolina to the south, and

Quebec to the north. Using the same methodology, Dennis recently conducted a more refined analysis

and revised the estimate of the Chesapeake Bay airshed upward to 1,081,600 square kilometers (see

Figure IV-2). Thus, nitrogen emitted to the atmosphere several States away can be deposited to the

watersheds of the Great Waters and to the waterbodies themselves. 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-45

Figure II-8

National NOx Emission Trends, 1985-1996

(U.S. EPA 1997f)

Figure II-10

1996 National Anthropogenic NOx Emissions by Principal Source Category 

(U.S. EPA 1997f)
CHAPTER II

ENVIRONMENTAL PROGRESS

Page II-46 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-9

1996 NOx Emissions by State (Thousand Metric Tons/Rank)

(U.S. EPA 1997f)
Chapter II

Environmental Progress

3

 Total inorganic N is calculated based on the sum of ammonium and nitrate nitrogen (Personal

Communication with Van C. Bowersox, NADP Coordinator, 12/9/98).

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-47

Figure II-11

Estimated Nitrogen Emissions to Air by Principal Source Category 

in North Carolina – Anthropogenic and Biogenic

(Aneja et al. 1998)

Nitrogen Deposition in the U.S.

Nitrogen compounds are deposited to surface media by dry and wet deposition. Rates and trends

of inorganic nitrogen wet deposition to the Great Waters can be evaluated based on data developed by the

National Atmospheric Deposition Program (NADP) National Trends Network (NADP/NTN), which 

monitors wet deposition rates for ammonium (NH4

+

) and nitrate (NO3) at approximately 200 monitoring

stations across the country. The network provides weekly and annual deposition rates for these two

nitrogen compounds (in terms of kg/ha as the ions) and for total inorganic nitrogen (in terms of kg/ha as

N).3 

The NADP/NTN has monitoring sites within the watersheds of most of the Great Waters,

providing measurements of nitrogen wet deposition to at least portions of the watersheds. Data from

monitoring points nearest the Great Waters can be extrapolated to estimate regional nitrogen wet

deposition to the Great Waters and their watersheds. While this approach involves increasing uncertainty

with increasing distance between monitoring sites and waterbodies, it nevertheless is currently the best

available approach for evaluating the trends in inorganic nitrogen wet deposition to the Great Waters. 

Figure II-12 presents rates of inorganic nitrogen wet deposition from the atmosphere as measured

at the NADP monitoring sites nationwide for 1997. Data from individual monitoring points have been

extrapolated in this figure to obtain isopleths for inorganic nitrogen wet deposition rates nationwide

(including the Great Waters). These data indicate that inorganic nitrogen wet deposition ranged from

lows of 0.1 kg/ha/yr in Alaska and 0.2 kg/ha/yr in Oregon to a high of 9.6 kg/ha/yr in upstate New York. 
Chapter II

Environmental Progress

Page II-48 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-12

Estimated Inorganic Nitrogen Wet Deposition, 1997

(NADP/NTN 1998a)

Adapted from http://nadp.sws.uiuc.edu.
Chapter II

Environmental Progress

3

 NADP data were analyzed by selecting the monitoring sites within the watersheds of the Great Waters

and averaging the reported deposition rates for all monitoring sites within each watershed to obtain an average

deposition rate for the watershed. Data from 9 monitoring sites were averaged for the Chesapeake Bay watershed;

data from 18 monitoring sites were averaged for the Great Lakes watersheds, and data from 4 monitoring sites were

averaged for the Lake Champlain watershed.

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-49

The NADP monitoring data suggest that the rates of inorganic nitrogen wet deposition to many

of the Great Waters watersheds have been relatively constant for the past two decades. Figures II-13, II14, and II-15 present the average rates of nitrogen wet deposition within the watersheds of three of the

Great Waters, from 1980 through 1997.3 Year-to-year patterns vary among watersheds, but all three

watersheds exhibit a similar trend – relatively constant rates of nitrogen wet deposition over this period. 

Data from other sources suggest that deposition trends vary locally, however. Deposition of NHx has

increased since 1980 in areas downwind of intensive livestock operations (Paerl 1999), and annual

atmospheric deposition of NO3, NHx, and total inorganic nitrogen measured at the NADP site nearest to

Tampa and Sarasota Bays has increased significantly in the past decade. The increase in nitrogen

atmospheric deposition near Tampa and Sarasota bays is correlated with increases in population in the

region over the same time period (Dixon et al. 1996). 

As with all dry deposition processes, nitrogen dry deposition is extremely difficult and expensive

to monitor directly, and no programs currently do this. The lack of a reliable approach for quantifying

dry deposition remains a significant gap in the understanding of nitrogen deposition processes and

effects. Dry deposition can be inferred based on the nitrogen content of atmospheric gases and particles

and computed deposition rates. Two networks are using this approach: NOAA’s Atmospheric Integrated

Research Monitoring Network (AIRMoN-dry) and the EPA-sponsored Clean Air Status and Trends

Network (CASTNet). However, extrapolation of inferred nitrogen dry deposition values to surrounding

areas is unreliable (Hicks 1998, Dennis 1999) and is still under investigation. In the absence of measured

nitrogen dry deposition rates, many investigators have attempted to estimate dry deposition based on a

ratio of dry deposition to wet deposition. A 1:1 ratio is most commonly derived (Hinga et al. 1991,

Valiela et al. 1997). However, this approach also introduces considerable uncertainty, and the 1:1 ratio is

applicable only for oxidized inorganic nitrogen, not ammonium compounds (Dennis 1999, Chimka et al.

1997). 

Organic nitrogen is also deposited from the atmosphere to the ground and surface waters. 

However, measurement of dry organic nitrogen deposition is unreliable and, to date, only a limited

number of measurements of organic nitrogen dry deposition rates have been made (Scudlark et al. 1998). 

Measurement of wet organic nitrogen is more reliable, and more and more data on wet deposition are

becoming available. Based on a number of measurements of the organic nitrogen content in precipitation

on the mid-Atlantic coast, Scudlark et al. (1998) found that organic nitrogen averages at least 20 percent

of total dissolved nitrogen in precipitation, and can comprise as much as 64 percent of total dissolved

nitrogen for single precipitation events. Based on measurements in North Carolina, Peierls and Paerl

(1997) determined that roughly 30 percent of dissolved nitrogen in precipitation and rainwater deposition

was organic nitrogen. Based on these results, it appears that organic nitrogen is a significant component

of atmospheric deposition nitrogen (ADN) loads to surface waters, although the current understanding of

the contribution of organic nitrogen to overall ADN is limited.
CHAPTER II

ENVIRONMENTAL PROGRESS

Page II-50 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-13

Nitrogen Wet Deposition in the Chesapeake Bay Watershed

(NADP/NTN 1998b)

Figure II-14

Nitrogen Wet Deposition in the Great Lakes Watersheds

(NADP/NTN 1998b)

Figure II-15

Nitrogen Wet Deposition in the Lake Champlain Watershed

(NADP/NTN 1998b)

Note: Total inorganic N expressed as N; NO3 and NH4

+

 expressed as the ions.
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-51

Atmospheric Nitrogen Loadings to the Great Waters

The total ADN load delivered to each of the Great Waters is a sum of the nitrogen deposited

directly to the waters surface, plus a portion of the nitrogen deposited to the watershed. Although only a

fraction of the atmospheric nitrogen deposited to watersheds ultimately reaches downstream Great

Waters waterbodies, ADN transfer from watersheds is nevertheless the more important pathway for

introduction of ADN to these waterbodies. This is due to the much larger areal extent of watersheds

relative to the surface areas of the receiving waterbodies. The portion of ADN transferred from

watersheds to downstream waterbodies is still relatively uncertain, and although several ongoing projects

are attempting to quantify this, the rate of ADN transfer from watersheds to downstream waterbodies

remains one of the greatest sources of uncertainty in estimating nitrogen and ADN loadings to surface

waters. Transfer rates appear to vary greatly among watersheds and among areas within watersheds. For

example, estimates of ADN transfer rates from various watershed areas to Great Bay Estuary, New

Hampshire and to Waquoit Bay, Massachusetts are presented in Table II-19. Table II-20 presents

estimated overall ADN transfer estimates for the watersheds of various coastal waterbodies (as developed

by a number of researchers using a variety of techniques). The ADN transfer rates in Tables II-19 and II20 were generally estimated based on estimated steady-state flux of nitrogen.

The ADN loads to surface waters join nitrogen loadings from a variety of other sources. Key

sources of nitrogen reaching surface waters via routes other than the atmosphere (i.e., point source

discharges, runoff, ground water) include (1) fertilizer from agricultural operations, recreation areas,

suburban lawns; (2) manure from animal production facilities; (3) municipal and industrial treatment

plant sludge and effluent and residential septic tanks; (4) crop residues (especially nitrogen-fixing crops

such as legumes); and, (5) industrial wastes.

Table II-21 presents a number of estimates of the total nitrogen load, the nitrogen load

attributable to ADN, and the portion of total nitrogen load represented by ADN for a number of Atlantic

and Gulf coast Great Waters (developed using a variety of techniques). Based on these data, ADN

contributes roughly 10 to 40 percent of total nitrogen loads reaching the bays and estuaries studied. If

these values are assumed to be representative of the remaining Great Waters in the east and Gulf coast

region, it is clear that ADN contributes very significantly to the total load of nitrogen reaching the Great

Waters of these regions. It should be noted, however, that ADN accounts for roughly only 1 percent of

nitrogen loadings in the Mississippi River basin, which has highly diverse sources of anthropogenic

nitrogen (Goolsby et al. 1998, as cited by Paerl 1999). The ADN is also likely to be a relatively less

important contributor to nitrogen loadings in Pacific coast Great Waters than is the case in the east and

Gulf coast areas, due to the prevailing westerly winds over Pacific coastal waters and their watersheds,

originating from unpolluted ocean areas. 
Chapter II

Environmental Progress

Page II-52 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table II-19

Transfer of Atmospheric Deposition Nitrogen (ADN) 

from Various Watershed Areas

Great Bay Estuary, New Hampshirea Waquoit Bay, Massachusettsb

Type of Area Receiving

ADN

Percent ADN

Transferred to

Estuary 

Type of Area Receiving

ADN

Percent ADN

Transferred to Bay 

Urban 38 Roads, runways,

commercial areas 25

Active agriculture 10 Agricultural land (other

than turf and cranberry) 10

Forest 5 Natural vegetation 9

Surface water in the

watershed 90 Ponds in the watershed 44

Wetlands 3 Cranberry bogs 10

Disturbed/open land 6 Turf 10

 a Talbot and Mosher 1998

 b

 Valiela et al. 1997

Table II-20

Transfer of Atmospheric Deposition Nitrogen (ADN) 

from Watersheds to Several Bays and Estuaries

Watershed 

Percent of ADN

Transferred to

Bay/Estuary

Reference

Albemarle-Pamlico Sounds 15 Paerl and Fogel 1994, as cited in Valigura et al.

1997

Chesapeake Bay 15 Linker 1998

Delaware Bay 9.4 Scudlark and Church, 1993, as cited in Valigura et

al. 1997

Long Island Sound 15 Long Island Sound Study, as cited in Valigura et al.

1997

Narragansett Bay 7 Hinga et al. 1991, as cited in Valigura et al. 1997

New York Bight 12 Hinga et al. 1991, as cited in Valigura et al. 1997

Waquoit Bay 11 Valiela et al. 1997
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-53

Table II-21

Atmospheric Nitrogen Loads Relative to Total Nitrogen Loads

 in Selected Great Waters*

Waterbody Total Nitrogen Load

(million kg/yr) 

Atmospheric Nitrogen

Load (million kg/yr)

Percent Load From

the Atmosphere

Albemarle-Pamlico Soundsa 23 9 38

Chesapeake Bayb 170 36 21

Delaware Bayc 54 8 15

Long Island Soundd 60 12 20

Narragansett Baye 5 0.6 12

New York Bighte 164 62 38

Based on ADN loads from the watershed only (excluding direct nitrogen deposition to the bay surface):

Waquoit Bay, MAf.022 .0065 29

Based on atmospheric N deposition directly to the Waterbody (excluding ADN loads from the watershed):

Delaware inland baysg 1.3 .28 21

Flanders Bay, NYh.36 .027 7

Guadalupe Estuary, TXi 4.2 - 15.9 .31 2 - 8

Massachusetts Baysj 22 - 30 1.6 - 6 5 - 27

Narragansett Bayk 9 .4 4

Newport River Coastal Waters, NCa.27 - .85 .095 - .68 >35

Potomac River MDl 35.5 1.9 5

Sarasota Bay, FLm.6 .16 26

Tampa Bay, FLn 3.8 1.1 28

*As cited in Valigura et al. 1997: aPaerl and Fogel 1994, bLinker 1998, cScudlark and Church 1993, dLong Island

Sound Study 1996, eHinga et al. 1991, fValiela et al. 1996, gDelaware Bays NEP, hPeconic Bay NEP, iBrock et al. 

1995, jMassachusetts Bays NEP 1996, kNixon et al. 1995, lBoynton et al. 1995, mSarasota Bay NEP 1995, nTampa

Bay NEP, Zarbock et al. 1994

Effects of Nitrogen Loadings on the Great Waters

While ADN contributes significantly to the overall adverse effects associated with excessive

nitrogen loadings to the Great Waters, the effects of atmospherically-derived nitrogen on the Great

Waters is very difficult to distinguish from the effects of nitrogen loadings from other sources. The

effects of atmospheric nitrogen deposition to the Great Waters and associated trends can only be

reviewed in terms of the effects of overall nitrogen loadings to these waters and the associated trends. 

Although historical data for total aquatic nitrogen concentrations in the Great Waters are not

available, nitrate concentrations have been monitored in many rivers and drinking water supplies in the

U.S. for decades. Nitrate (NO3) concentrations in surface water are directly related to anthropogenic

nitrogen loadings to watersheds and surface waters (Vitousek et al. 1997). Aerosol nitrate is the most

mobile form of nitrogen in watersheds and aquatic systems, and other forms of anthropogenic nitrogen,

notably NHx and organic nitrogen, are partly oxidized to NO3in the environment (Hessen et al. 1997). 

Surface water NO3 concentration trends, although only part of the picture, provide some insight on the

trends in anthropogenic nitrogen loadings and their effects on the Great Waters.

Available data indicate a significant increasing trend in the fluxes of nitrates in major surface

waters in the U.S., including the Great Waters and their tributaries.
Chapter II

Environmental Progress

Page II-54 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

C Nitrate has more than doubled in the Mississippi River since 1965 (Vitousek et al. 1997). Note,

however, that ADN accounts for roughly only 1 percent of nitrogen loadings in the Mississippi

River basin (Goolsby et al. 1998, as cited by Paerl 1999). 

C Nitrate fluxes in 10 major rivers feeding coastal waters in the northeastern U.S. have increased

by factors of three to eight since 1900 (Jaworski et al. 1997). This increase is correlated with a

three- to five-fold increase in NOx emissions in the watersheds of these same rivers and more

than a four-fold increase in atmospheric nitrogen deposition rates to northeastern coastal

watersheds over the same time period (Vitousek et al. 1997).

C Increases in surface water nitrogen concentrations of 10 to 25 percent have been observed in

Long Island Sound, portions of the Potomac River, and the Chesapeake Bay, the Neuse River,

and portions of Biscayne Bay over the past 2 to 15 years (NOAA 1996, NOAA 1997a, as cited in

U.S. EPA 1997f).

The long-term upward trend in nitrogen fluxes and nitrogen concentrations in many surface 

waters reflects similar upward trends in atmospheric emissions of nitrogen, in fertilizer use, and in

municipal wastewater discharges in the initial seven decades of this century. Some evidence suggests,

however, that nitrogen fluxes attributable to atmospheric deposition may have leveled off in more recent

years in at least some waterbodies. 

C Based on historical watershed data, Jaworski et al. (1997) found that nitrogen fluxes (total and

attributable to ADN) for a number of northeastern U.S. coastal waters rose rapidly until about

1970, but have been more or less constant since then.

C Stoddard et al. (1998) found that the nitrate concentrations in higher elevation lakes and streams

in the northeastern U.S. have either remained relatively constant or shown no discernable trend

since the early 1980s. Atmospheric deposition nitrogen is the principal and, in some cases, the

only source of anthropogenic nitrogen loadings to these lakes, which feed tributaries of the Great

Waters.

Fluxes of ADN and total nitrogen to some of the Great Waters may, therefore, have leveled off in

recent years. For many of the Great Waters, however, these fluxes remain many times greater than

natural levels that occurred prior to human activity in the watersheds and airsheds (Vitousek et al. 1997). 

Human loadings of nitrogen to the land can overwhelm the capacities of watersheds to assimilate

nitrogen, meaning that greater and greater percentages of the nitrogen deposited to watersheds are

transferred directly to downstream waterbodies. Thus, constant rates of nitrogen deposition to

watersheds can result in increasing nitrogen loadings to downstream waterbodies. Loadings of nitrogen

to waterbodies can similarly overwhelm the capacity of waterbodies to assimilate or eliminate nitrogen,

leading to a significant buildup of nitrogen concentrations and, in some cases, nitrogen saturation and

related ecosystem degradation (Vitousek et al. 1997, Moffat 1998). These factors are believed to

contribute to significant increases in concentrations of nitrogen in some of the Great Waters and rivers

feeding the Great Waters, specifically the Mississippi River and a number of major rivers in the

northeastern U.S. (Vitousek et al. 1997). 

 

The “natural” or ecologically ideal concentration of nitrogen in the water column varies

considerably among waterbodies. As one example, the Chesapeake Bay Program (1992, as cited in U.S.

EPA 1998b) has determined that the most desirable concentration of dissolved inorganic nitrogen in the

Chesapeake Bay (i.e., the concentration necessary to promote continued survival of submerged aquatic

vegetation) is <0.15 mg/L. 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-55

Recent NOAA Estuarine Eutrophication Surveys (NOAA 1996, 1997a, b, c, as summarized in

U.S. EPA 1998t) indicate elevated nitrogen concentrations in many of the Great Waters coastal estuaries

on the Atlantic and Gulf coasts. These surveys found the following: 

C High aquatic nitrogen concentrations (> 1 mg/L) in two of 18 estuaries on the U.S. north Atlantic

coast, 14 of 22 mid-Atlantic estuaries, 11 of 21 south Atlantic estuaries, and 18 of 37 Gulf of

Mexico estuaries; and,

C Moderate to moderately elevated aquatic nitrogen concentrations (0.1 - 0.9 mg/L) in 13 of 18

north Atlantic estuaries, five of 22 mid-Atlantic estuaries, seven of 21 south Atlantic estuaries,

and 19 of 37 Gulf of Mexico estuaries.

Excess nitrogen loadings in the Great Waters can have a range of effects on the ecological

structure and processes of these waters and, ultimately, on human use of the waters. Effects of excess

nitrogen loadings can be considered in three broad categories (U.S. EPA 1997a).

1. Dramatic increases in plant productivity and algal blooms in systems where algal growth was

previously nitrogen-limited. This can in turn cause fish kills, loss of submerged aquatic

vegetation due to reduced sunlight penetration, loss of recreational use of waterbodies, and

ultimately hypoxic (low oxygen) or anoxic (no oxygen) conditions as algal blooms die and

decomposition processes consume the available oxygen – a condition referred to as

eutrophication. Hypoxic and anoxic conditions can lead to loss of aquatic biodiversity as species

requiring higher oxygen concentrations are lost, can affect the biogeochemical cycling of

nutrients and toxic compounds, and can affect the bioavailability of toxic compounds. In

addition to these consequences associated with normal algal blooms, excess nitrogen loadings are

also linked to harmful or toxic algal blooms, often referred to as red or brown tides, involving

algae species that are toxic to other aquatic biota or humans, often causing fish kills and human

illness or mortality (Paerl et al. 1999, 1998, Paerl 1997a, Pelley 1998, Tibbets 1998, Rabalais et

al. 1996).

2. Changes in the ecological balance brought on by fundamental changes at the base of the food

web (i.e., the loss of aquatic grasses and other vegetation and the dominance of a relatively few

algal species) and loss of biological diversity throughout the system as fundamental aquatic

ecological parameters such as oxygen level, sunlight penetration, diversity and abundance of

food species, and habitat availability change.

3. Direct toxicity of some nitrogen compounds to aquatic organisms. Toxicity of nitrogen

compounds to aquatic organisms is not well understood, but mounting evidence suggests that

these compounds can affect the ability of some species to adapt to other stresses (Linton et al.

1998). Dissolved ammonia at concentrations above 0.2 mg/L can be toxic to aquatic organisms

(Paerl 1997a, as cited by U.S. EPA 1997a).

Many of these adverse effects have been observed by researchers in the Great Waters. Examples

are provided below.

C McClelland and Valiela (1998) and Short and Burdick (1996) found that increased loads of

anthropogenic nitrogen to Waquoit Bay, Massachusetts have a significant effect on the pathways

by which nitrogen enters the food web. The diets of primary consumers in the bay are influenced

by the dominant forms of food material available. Eelgrass is an important dietary component of

primary consumers in areas of the bay receiving lower anthropogenic nitrogen loadings. 
Chapter II

Environmental Progress

Page II-56 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Laboratory studies by Short and Burdick (1996) indicated that excessive nitrogen loadings

stimulated growth of algal competitors that shade and stress eelgrass. These laboratory results

were borne out in field observations in Waquoit Bay, where domination by algal competitors was

observed in areas of significant eelgrass decline. McClelland and Valiela (1998) found that

eelgrass is lost and is largely replaced by algae in areas of the bay receiving higher anthropogenic

nitrogen loadings. Thus, an important pathway for nitrogen entry to the food web may be

altered. McClelland and Valiela conclude that this change in the nitrogen pathway probably

affects the rate and manner in which nitrogen is cycled within the bay ecosystem and may reduce

the stability of shallow estuarine ecosystems in the bay. Loss of eelgrass also results in loss of

habitat for shellfish and other small fish, further affecting the ecological structure and function of

the bay.

C Allen and Hershey (1996) demonstrated that the immediate effects of atmospheric deposition of

nitrogen can vary seasonally for some waterbodies. In a north shore river tributary to Lake

Superior, availability of nitrogen was found to alternate with availability of phosphorus and other

factors as the limiting factor controlling algal biomass growth. Introduction of additional

nitrogen resulted in increased algal biomass during early summer and late summer, but not

during other seasons. Introduction of additional phosphorus caused increased algal growth in

spring, but not in other seasons. Algal growth was not affected by additional nitrogen or

additional phosphorus during the fall season, suggesting limitation by factors other than nitrogen

or phosphorus availability. The dissolved inorganic nitrogen to soluble reactive phosphorus

(DIN/SRP) ratio was not a reliable predictor of nutrient limitation in the studied river. 

C Linton et al. (1998) found that the combination of global warming and increased ammonia

loadings from atmospheric and other sources could have a greater impact on aquatic species in

Lake Superior than either factor alone. These researchers studied rainbow trout reactions to

elevated aquatic ammonia concentrations in conditions simulating Lake Ontario under a global

warming scenario (2 EC above natural water fluctuating water temperature cycle). Their results

indicate that elevated ammonia concentrations could reduce the ability of rainbow trout to adapt

to long-term, small temperature increases such as could be caused by global warming.

C The disappearance of the economically important scallop from Tampa Bay waters is attributed to

algal blooms and associated changes in ecological conditions in the bay, which in turn is

attributed to excess nitrogen loadings (U.S. EPA 1997a).

C Hypoxia attributed to nitrogen-induced eutrophication is now a common and recurring condition

in many bays along the Atlantic and Gulf coasts, notably Long Island Sound, New York-New

Jersey Harbor, Chesapeake Bay, Albemarle-Pamlico Sound, and the Mississippi Delta region

(U.S. EPA 1997a).

C Major algal blooms attributed to increases in aquatic nitrogen concentrations have occurred in

several Atlantic and Gulf coast waters in recent years. These blooms have been accompanied by

deleterious visual and odor effects and fish kills (U.S. EPA 1997a).

• The number of U.S. coastal areas experiencing major, recurring harmful or toxic algal blooms,

linked to increases in aquatic nitrogen availability, have doubled since 1972 and include areas

on the Atlantic, Gulf of Mexico, and Pacific coasts (Pelley 1998, Tibbetts 1998). 

 

The NOAA Estuarine Eutrophication Surveys (NOAA 1996, 1997a, b, c, as summarized in U.S.

EPA 1998t) indicate that the adverse effects of excess nitrogen concentrations are currently evident to
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-57

greater or lesser degrees in approximately 89 percent of the U.S. coastal estuary Great Waters. These

surveys report the following:

C Anoxic or hypoxic conditions (oxygen content 0 - 2 mg/L) in portions of four of 18 north

Atlantic estuaries, 13 of 22 mid-Atlantic estuaries, 13 of 21 south Atlantic estuaries, and 26 of 37

Gulf of Mexico estuaries; and,

C Biologically stressful levels of oxygen (2 - 5 mg/L) in at least portions of nine of 18 north

Atlantic estuaries, 21 of 22 mid-Atlantic estuaries, seven of 21 south Atlantic estuaries, and 35 of

37 Gulf of Mexico estuaries.

Human Health Effects of Nitrogen in the Great Waters

Under the Safe Drinking Water Act, EPA set maximum contaminant levels (MCLs) for nitrate

and nitrite in drinking water to protect human health. These levels are established at 10 mg/L of nitrate

and 1 mg/L of nitrite. The primary adverse human health effect associated with exposure to nitrate or

nitrite is methemoglobinemia, a dangerous condition in which nitrite in the blood stream prevents oxygen

transport, potentially leading to brain damage or death. This condition is rare in adults, but is a

significant danger for infants because microbes present in the stomachs of infants can convert large

amounts of nitrate to nitrite. The National Research Council concluded, in 1995, that results from

epidemiological studies are inadequate to support an association between nitrate or nitrite exposure from

drinking water in the U.S. and increased cancer rates in humans. However, an epidemiological study led

by a researcher from the National Research Council, published in 1996, of rural populations using

community water supplies in Nebraska concluded that long-term exposure to elevated nitrate levels in

drinking water may contribute to the risk for non-Hodgkin’s Lymphoma. Research is continuing in this

area (U.S. EPA 1997h, Ward et al. 1996).

Data indicate that most of the Great Lakes nearshore waters can be used as a source of drinking

water with normal treatment, meeting the nitrate and nitrite levels (U.S. EPA 1998n). Similarly, Lake

Champlain was not associated with any violations of standards in place for drinking water supplies due to

Great Waters pollutants of concern from 1986 to 1995 (Lake Champlain Basin Program 1999). Further

reductions in pollutant concentrations may reduce the cost of drinking water treatment in some areas.

Excess nutrients in coastal waters have also been implicated in the increased incidence of

harmful or toxic algal blooms in the coastal waters of nearly every U.S. coastal State. These blooms

have been linked to health effects among exposed human populations ranging from shortness of breath to

dizziness, diarrhea, disorientation, permanent memory loss, and occasion death (Pelley 1998, Tibbetts

1998). To the extent that ADN contributes to elevated nitrogen content in coastal waters, ADN also

contributes to human health risks associated with harmful and toxic algal blooms. No evidence exists to

date suggesting negative human health effects attributable directly to atmospherically-derived nitrogen in

the Great Waters.
Chapter II

Environmental Progress

Page II-58 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

HIGHLIGHTS

Polychlorinated Biphenyls

' Sources. In general, the number and magnitude of

PCB sources have decreased 20-fold in the past 20

years. PCB sources generally are limited to atmospheric

deposition and localized stationary sources. The largest

national-level stationary air emission source of PCBs is

hazardous waste incineration, along with several smaller

sources. Sources to surface waters include atmospheric

deposition, urban runoff, resuspension of contaminated

sediments, and recycling through volatilization followed

by deposition.

' Loadings. In the Great Lakes, studies show that

deposition of PCBs has decreased and that PCBs in

surface waters may be in equilibrium with the

atmosphere (i.e., no net loadings). Deposition rates are

higher near the Chicago urban area when compared to

offshore and rural locations. In the Chesapeake Bay, a

net loss of PCBs from the water surface has been

observed.

' Environmental Concentrations and Exposure. 

PCB contamination levels in biota from the Great Lakes

have declined; however, certain human subpopulations

continue to be exposed to PCBs through fish

consumption. In the Chesapeake Bay, maximum PCB

sediment concentrations are below the PEL and NOEL

for aquatic biota, with the exception of one location on

the James River. 

BANNED AND RESTRICTED USE SUBSTANCES

Polychlorinated Biphenyls

(PCBs)

Manufacture of PCBs in the U.S. was

voluntarily stopped in the late 1970s, and the

use of PCBs was restricted under the Toxic

Substances Control Act (TSCA) in 1979. 

Therefore, sources of PCBs in the U.S. are

limited. However, PCBs are still present in

older commercial and industrial equipment

(e.g., electrical transformers and capacitors)

and are released from non-point and nonregulated sources including Superfund sites. 

In addition, despite reductions in use, PCBs

are released during some combustion

processes, such as the incomplete burning of

PCB-containing wastes during incineration. 

New research is also indicating that PCBs are

actually being formed during certain

combustion processes, similar to the way in

which dioxins and furans are formed (Lemieux

et al. 1999).

The number and magnitude of sources

of PCBs have decreased 20-fold in the last 20

years, and sources of PCBs generally are

limited to atmospheric deposition and

localized point source discharges (Froese et al.

1997). Some studies detected PCBs in

smallmouth bass from Fumee Lake, a remote lake in Michigan (Henry et al. 1998), and in the blubber of

Beluga whales from Alaska’s north coast (Wade et al. 1997a), indicating long range transport and

atmospheric deposition as a major source in these areas. Many recent studies in the Great Waters,

however, implicate non-atmospheric sources of PCBs (e.g., Brazner and DeVita 1998, Metcalfe et al.

1997a). The relative importance of atmospheric inputs and non-atmospheric sources remains unclear. 

Nevertheless, the largest stationary source of PCB air emissions on a national basis, as indicated by

EPA’s 1990-1993 NTI, is hazardous waste incineration at dedicated hazardous waste incinerators, along

with several other smaller sources (Table II-22) (U.S. EPA 1999a). The EPA is pursuing additional

research to determine the extent of PCB releases during incomplete combustion in these and other

facilities as well as the effects on emissions and loadings of PCBs.

In Lake Superior, specifically, approximately 52 kg/year of PCBs are from point source inputs,

15 kg/year are from runoff (including pollutants in rainfall plus pollutants that are transported from land

areas), and 85-156 kg/year are from wet and dry deposition (Hoff et al. 1996). Similarly, water samples

collected during an investigation of the source of PCBs in the Detroit River (which feeds Lake Erie)

indicate that the dominant sources of PCBs in this location are surface runoff from urban areas during

rainfall and resuspension of in-place deposits of PCBs in the sediments of the river and bays due to high

flow events in the rivers and due to severe wind conditions in the lakes (Froese et al. 1997). 
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-59

Table II-22

National Anthropogenic PCB Air Emissions 

(Based on EPA’s 1990-1993 National Toxics Inventory)

Source Category

Anthropogenic

Air Emissions

(tons/year)

Percent Contribution to

Total U.S. Anthropogenic

Air Emissions

Hazardous waste incineration 0.03 56.0

Sewage sludge incineration 0.005 10.3

Fabricated metal products, nec 0.005 10.1

Industrial boilers: natural gas combustion 0.004 7.7

Portland cement manufacture: all fuels 0.004 7.3

Scrap and waste materials 0.001 2.7

Scrap tire combustion 0.001 2.1

Refuse systems 0.0006 1.2

Fabricated rubber products, nec 0.0005 1.0

Others (< 1 percent) a 0.0008 1.7

Total U.S. Anthropogenic PCB Air Emissions 0.052b 100b

 a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in 

Appendix B.

b This value represents anthropogenic PCB air emissions in the U.S. only.

 Source: U.S. EPA 1999a

Research based on deposition monitoring under the Atmospheric Exchange Over Lakes and

Ocean Surfaces (AEOLOS) project found that the “urban plume” of Chicago increases the deposition of

PCBs to Lake Michigan and is a major source of atmospheric PCBs to coastal Lake Michigan. Total

ambient air PCB concentrations on the lakeshore near Chicago are two to three times higher than

background levels and the values collected under IADN, which monitors remote locations on the Great

Lakes (Offenberg and Baker 1997). Franz et al. (1998) found similar results using dry deposition

monitoring data from AEOLOS and the Lake Michigan Mass Balance Study where fluxes of particulate

PCBs were higher in Chicago than less than 15 km offshore and at rural sites. The higher urban fluxes

are due to increased anthropogenic activity and the greater atmospheric burden of large particles that are

generated in the urban area and deposited closer to their sources. Franz et al. (1998) estimated dry

deposition of PCBs to Lake Michigan to be approximately 1,100 kg/year, which is at least an order of

magnitude greater than some previously reported values. Other studies report inputs of PCBs through

air/water exchange at approximately 880 kg/year and wet deposition at 50 - 250 kg/year (Franz et al.

1998). In contrast, Offenberg and Baker (1997) found that the amount of yearly wet deposition plays a

major role in determining the annual deposition of PCBs to Lake Michigan, and IADN monitoring results

indicate that gas absorption is a dominant deposition process for delivering PCBs to lake surfaces

(U.S./Canada IADN Scientific Steering Committee 1998). The observed differences from these studies

illustrate the importance of considering local meteorology and the location of monitoring stations (rural

versus urban) when interpreting deposition data. 

 In addition to depositing PCBs released to the atmosphere from emission sources, atmospheric

deposition processes play a strong role in PCB recycling in Lakes Superior, Michigan, and Huron, but
Chapter II

Environmental Progress

Page II-60 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

less of a role in Lakes Erie and Ontario. Volatilization of PCBs from the water, however, is the dominant

mechanism for exchange of PCBs between the lakes and the atmosphere. According to IADN

monitoring data from 1988 to 1996, wet and dry deposition of PCBs to each of the Great Lakes decreased

(Hoff et al. 1996) (Table II-23). In the Detroit River, which is a heavily industrialized and urbanized area

and is a primary transport route of PCBs to Lake Erie and Lake Ontario, the mass of PCBs transported

through the Trenton Channel to the western basin of Lake Erie in 1995 was estimated at 600 kg/yr,

constituting a potential decrease from 1986 estimates of approximately 1,500 kg/year. (Note, however,

that different sampling methodologies were employed in the different years and may be responsible for a

portion of the change (Froese et al. 1997)). Other monitoring studies show a net loss of PCBs to the

atmosphere, particularly from Lake Superior and Lake Michigan (Offenberg and Baker 1997, U.S. EPA

1998m). For example, PCBs are being purged from Lake Superior at 21 percent per year of its annual

burden (Hoff et al. 1996). Another monitoring data analysis indicates that gas transfer of PCBs out of the

lakes is counteracted by net deposition, meaning PCBs are in equilibrium with the water surface and the

atmosphere (Hillery et al. 1997).

Table II-23

IADN Loading Estimates of PCBs (wet and dry) for the Great Lakes (kg/year)

Year Superior Michigan Huron Erie Ontario

1988 550 400 400 180 140

1992 160 110 110 53 42

1994 85 69 180 37 64

1996 50 42 N/A 34 N/A

 Source: U.S. EPA 1998l

 Studies using surface water and air sampling indicate that Chesapeake Bay waters have higher

relative concentrations than the overlying atmosphere, and volatilization is the dominant loss process for

PCBs from the bay. Polychlorinated biphenyls are volatilizing to the atmosphere at an average rate of 35

μg/m2/yr, with a range of 31 to 112 μg/m2/yr. Annual loss of PCBs from the bay from net volatilization

(403 kg/yr) is 10 times greater than inputs from wet and dry deposition of 37 kg/yr and is more than two

times greater than the loadings from the Susquehanna River of 165 kg/yr (Nelson et al. 1998). The

Chesapeake Bay Program’s 1999 Toxics Loading and Release Inventory (TLRI) provides information on

the total inputs and relative atmospheric inputs of PCBs to the tidal and non-tidal waters of the

Chesapeake Bay based on monitoring data. Total PCB inputs to the Chesapeake Bay, without point

source estimates, are similar for both inputs from the non-tidal watershed (254 kg/year) and inputs from

wet and dry atmospheric deposition to the tidal waters (245 kg/year) (Chesapeake Bay Program 1999a).

The comparison of current contamination levels to historical values provides evidence that

concentrations of PCBs in biota have declined in the Great Lakes. For example, Dykstra et al. (1998)

measured PCB concentrations in nestling blood (1989-1994) and addled eggs (1986-1993) of bald eagles

in Lake Superior and inland Wisconsin sites. A comparison to published and unpublished historical data

of PCBs in addled bald eagle eggs on Lake Superior indicates that PCB levels declined significantly

between 1969 and 1993; however, PCBs may still be at levels high enough to affect reproductive success. 

Similarly, Ion et al. (1997) measured the concentration of PCBs in yellow perch from the St. Lawrence

River between 1975 and 1991-1992. Comparison of average PCB concentrations detected to historical

levels in St. Lawrence River fish indicates that levels have decreased by a factor of 30 since 1975. The

concentration of PCBs in all fish sampled by Ion et al. (1997) were below the International Joint
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-61

Commission guideline of 100 ng/g in whole fish, which is protective of aquatic life and consumers of

fish.

A study by Eby et al. (1997) shed doubt on findings reported in the Second Great Waters Report

to Congress that concluded that PCB concentrations in Great Lakes have leveled off or even increased

slightly in the last 10 years (U.S. EPA 1997b). In those earlier studies, scientists hypothesized that the

trend in PCB contamination could be due to changes in the composition of the food web. Eby et al.

(1997) demonstrate, however, that sampling methodology may have influenced the apparent PCB

concentration trends rather than changes in fish diet. As part of a long-term PCB monitoring survey, the

USGS collects and analyzes bloaters (Coregonus hoyi) from the same site in Lake Michigan every year. 

Because fish size is used to predict fish age, similar size fish are collected each year. However, since the

early 1980s, bloater populations experienced a decline in growth rate due to a shift in diet, which placed

older, more contaminated bloaters in the size range sampled. This resulted in an apparent trend of steady

state or increasing PCB levels. In contrast, Eby et al. (1997) modeled an increase in the amount of the

most contaminated prey in the bloater diet and found that this shift in diet had little effect on PCB

contamination levels in bloaters.

A recent study by Haffner et al. (1997) found that total PCB concentrations in herring gull eggs

decreased significantly between 1981 and 1992 in Lake Ontario and Lake Erie, although the decrease in

lake Erie was not of the same magnitude. The PCB concentrations detected during this study are not

expected to affect reproduction in herring gull populations. In addition, Haffner et al. (1997) found that

total PCB concentrations in double-crested cormorant eggs did not decrease in Lake Ontario but

decreased slightly in Lake Erie between 1981 and 1992. The PCB concentrations detected in this study

may be high enough to cause toxicological stress on the cormorant population (e.g., egg mortality,

infertility, deformity).

Although some studies indicate that PCB levels in fish have decreased or reached a steady state

in recent years, consumption of contaminated fish from the Great Lakes remains a concern. Several

recent studies examined the relationship between increased health risks in certain subpopulations and the

consumption of fish from the Great Lakes contaminated with PCBs, concluding that certain

subpopulations continue to be exposed to PCBs through fish consumption despite declines in

contamination levels and despite continued fish consumption advisories. Study results include the

following.

C Pellettieri et al. (1996) determined that the estimated PCB intake for sport fisherman in the

Chicago area exceeded the level recommended by the Great Lakes Advisory Task Force of no

more than one meal of fish per week (assuming the average meal of fish is composed of 227 g of

uncooked fish and that the intake of PCBs is reduced by half due to skinning, trimming, and

cooking).

C A study of Ojibwa tribal members from the Great Lakes region indicated that PCB

concentrations in Ojibwa populations were low with a maximum value of 9.6 ppb in blood

serum; however, a significant association was found between serum PCB concentration and age

(Gerstenberger et al. 1997). This is important because PCBs are persistent and bioaccumulate in

the food chain. 

C According to a 1997 survey (Tilden et al. 1997) of Great Lakes States’ residents, the most widely

accepted fish consumption advisory recommendation was cleaning and cooking methods. A

study of six cooking methods determined that choice of cooking method greatly impacted the

loss of PCBs during the cooking process, with smoking and microwave baking as the most
Chapter II

Environmental Progress

Page II-62 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

HIGHLIGHTS

Pesticides

' Sources. Because most of the Great Waters

pesticides of concern are banned or restricted use 

substances, the major sources include long range 

transport from other countries, use of existing 

pesticide stocks, and releases from contaminated

sites and soils.

' Loadings. Since many of these pesticides are 

persistent and bioaccumulative, they are cycling 

between environmental compartments. In general,

deposition of these substances remained constant or

declined in recent years. 

 

' Environmental Concentrations. DDT and its

metabolites have, in general, declined to levels below

which adverse environmental effects of concern are

expected. In Chesapeake Bay sediments, chlordane

and dieldrin concentrations were between the level

expected to show widespread effects and the level

expected to show limited effects.

effective methods. Smoking reduced PCB levels by 65 percent, and microwave baking reduced

PCB levels by 60 percent (Salama et al. 1998).

In a sediment contamination study of the Chesapeake Bay and its tributaries from 1984 to 1991

by Eskin et al. (1996) under the Chesapeake Bay Program, PCBs were detected at low levels in sediments

throughout the bay and its tributaries, indicating that aquatic life impacts (based on the aquatic biota

NOEL and PEL) from PCBs in the bay are not widespread. The highest concentrations were detected in

sediments in the northern bay near the Baltimore area and on the James River. Maximum PCB

concentrations were below aquatic biota NOEL and PEL concentrations in sediments at all locations,

with the exception of one location on the James River.

Despite observed declines in some organisms, a study of PCB levels (as serum concentrations) in

male and female juvenile American alligators in Lake Apopka, Florida indicated that 23 of 28 PCB

congeners were present in juvenile alligators. The mean total PCB concentration in the serum was 1.54 ±

0.12 (SE) ng/mL. Alligators in Lake Apopka have been reported to have a number reproductive and

endocrine system abnormalities which may be due to embryonic exposure to these and other compounds

(Guillette et al. 1999). 

Pesticides

Table I-1 presents the uses and sources

of Great Waters pesticides and indicates that

many of these pesticides are banned or use

restricted; however, many of these pesticides

may still be used in other countries. Therefore,

long-range transport of emissions from other

countries may contribute to current levels in

Great Waters along with other current sources,

such as use of existing stocks of pesticides, and

releases from contaminated sites (e.g.,

Superfund sites) and from soils upon which

pesticides were applied in the past. Because

most of these pesticides are persistent and

bioaccumulative, pesticides that were used or

unintentionally released previously can cycle

between environmental compartments (e.g., air,

water, soil, sediment, biota). Therefore, some of

these pesticides can be re-released to the

atmosphere, transported short or long distances,

and redeposited to surface waters. 

Given these possible sources of banned and restricted use pesticides, efforts to reduce releases

focus primarily on promoting (1) international agreements to reduce or eliminate the manufacture and use

of these pesticides, and (2) pesticide collection programs (i.e., Clean Sweeps as described on page III56). Additional future reductions may result from the clean up of existing stockpiles and contaminated

sites. Research continues at EPA and other institutions on soil remediation methods that will reduce

emissions of these pollutants from contaminated sites. In addition, efforts to limit the exposure of human

and ecological populations to these pesticides include EPA and other agency monitoring programs and

continued outreach activities to make the public aware of contaminated fish and waterbodies. Some
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-63

recent studies of these pesticides focus on the role of atmospheric transport, both historic and current, in

the contamination of waterbodies and biota of the Great Waters.

Atmospheric transport and deposition of these pesticides remains a principal source in the Great

Waters, as shown by studies of both regional and global transport. For most pesticides, however, the

relative contribution of atmospheric deposition versus other sources (e.g., runoff from contaminated

soils, groundwater contamination) to total loadings is not yet known. It is expected that with the

development of mass balance models and better sources and emissions estimates, it will be possible to

determine relative contributions of different sources of pesticides and other pollutants to the Great

Waters waterbodies. Furthermore, the contamination of biota in remote waterbodies that receive no point

source inputs emphasizes the role of atmospheric transport and deposition of pesticides. For example,

DDT/DDE, toxaphene, chlordane, dieldrin, and hexachlorobenzene were detected in smallmouth bass

from Fumee Lake, which is in the Upper Peninsula of Michigan. The remote location of Fumee Lake

suggests atmospheric loading is the source of pesticide contamination. Concentrations of these pesticides

(except toxaphene which is associated with elevated levels in Lake Superior because of point source

inputs) were similar to those found in fish from Lake Superior, where atmospheric inputs are thought to

be the primary source of contaminants. All pesticide concentrations were less than those reported in

Lake Michigan, which typically receives contaminants by direct input from point sources as well as

atmospheric deposition (Henry et al. 1998). The detection of toxaphene, DDT/DDE, and chlordane in

the blubber of Beluga whales from Alaska’s north coast (Wade et al. 1997a) demonstrates the global

scale of atmospheric transport. Toxaphene, chlordane, lindane, "-HCH, hexachlorobenzene, dieldrin,

and DDE also were detected in a variety of organisms at multiple trophic levels in Lake Superior

(Kucklick and Baker 1998). 

Banning and restricting uses of these pesticides under the Federal Insecticide, Fungicide, and

Rodenticide Act (FIFRA) in the past 25 years have proven to be the most effective methods of removing

these compounds from the environment, as would be expected. Because these substances are no longer

intentionally released in the U.S. and the goal was to remove them from the environment, a group of

researchers investigated how long these pesticides would persist in the atmosphere above the Great

Lakes. Cortes et al. (1998) calculated atmospheric half-lives (i.e., the amount of time required for the

concentration in the air to decrease by 50 percent) and used measured atmospheric concentrations to

estimate minimum virtual elimination dates (i.e., when the contaminant levels are below the detection

limits of the measurement equipment) in the Great Lakes regional atmosphere for DDT, DDE, dieldrin,

chlordane, lindane ((-HCH), and hexachlorobenzene (HCB) (Figure II-16). Based on these dates, DDT

and DDE will be the first compounds to be reduced to concentrations below current detection limits in

the Great Lakes atmosphere, followed by dieldrin and chlordane between 2010 and 2030, (-HCH by

2030, and HCB by 2060. These estimates assume current rates of long-range transport of these pollutants

into the region. Because of their persistence, it should be noted that elimination of these pollutants in the

atmosphere does not mean that concentrations would be eliminated in deposited media by these dates. 

However, these estimates indicate that reduction strategies in the Great Lakes, along with the original

bans or restrictions on the use of these substances, are having the intended effect.

DDT/DDD/DDE. In general, several studies indicate declines in atmospheric deposition of DDT

and its metabolites as well as declines in concentrations in different environmental media. According to

deposition monitoring data collected under IADN, wet and dry deposition of DDT to Lakes Superior,

Michigan, and Erie in 1996 was less than values from 1994, 1992, and 1988 (Table II-24) (U.S. EPA

1998l). The IADN data from 1993-1994 indicate that the net flux of total DDT is into Lake Superior and

Lake Erie, possibly due to the high levels of wet deposition during 1993-1994. In Lake Huron, there is a

net loss of total DDT to the atmosphere, and total DDT is in equilibrium between the surface water and

the atmosphere in Lake Ontario. These data indicate a reversal from net volatilization of total DDT from 
Chapter II

Environmental Progress

Page II-64 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-16

 Expected Year that Great Waters Pesticides will be Below Current Detection Limits in

the Great Lakes Atmosphere

(Cortes et al. 1998)

Table II-24

IADN Loading Estimates of DDT (wet and dry) to the Great Lakes (kg/year)

Year Superior Michigan Huron Erie Ontario

1988 90 64 65 33 26

1992 34 25 25 12 10

1994 17 32 37 46 16

1996 4 12 N/A 2 N/A

Source: U.S. EPA 1998l

some of the lakes to net deposition to those lakes (U.S./Canada IADN Scientific Steering Committee

1998). 

Current data indicate that elevated air concentrations of DDT and its metabolites in the South

Haven, Michigan area are due to volatilization from the soil where the pesticide was placed during

historical applications (Michigan Department of Environmental Quality 1998). The Great Lakes

National Program Office (GLNPO; see page III-35) is funding a study to evaluate the source of the DDT

and its metabolites in the air near a large fruit-growing area in South Haven where, historically, a number

of researchers detected elevated levels of DDT and its metabolites. These levels are about 20 times

greater than concentrations detected elsewhere in the Great Lakes basin. Recent studies that reported on

DDT and DDE levels at a Canadian IADN site in Egbert, Ontario found that while increased levels in

Egbert were not as pronounced as those in southwest Michigan (i.e., less than half), back trajectory

analysis indicated that air parcels with elevated DDT and DDE levels usually had passed through South
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-65

Haven, Michigan. South Haven is located in an area which is primarily devoted to fruit and vegetable

production where the historic application of DDT could have been extensive. However, another potential

source of DDT and its metabolites could be the current use of dicofol (1,1-bis(4’-chlorophenyl)2,2,2-

trichloroethanol). It has been postulated that agricultural practices and air-soil diffusion affect DDT

volatilization rates from soil. Therefore, a study by the Michigan Department of Environmental Quality

is under way to determine impacts of tillage practices on ambient DDT levels in southwest Michigan and

to assess any possible long-range transport effects (Michigan Department of Environmental Quality

1998). 

Brazner and DeVita (1998) detected DDE in yellow perch and spottail shiners from 23 sites in

Green Bay, Lake Michigan. Because the overall distribution of DDE tissue concentrations was fairly

uniform within the bay, DDE contamination probably originates primarily from non-point sources,

including atmospheric deposition. The few sites that exhibited unusually high DDE residues in fish may

have point sources of DDE in nearby rivers.

1,1'-(dichloroethenylidene)bis(4-chlorobenzene), or DDE, has been detected in a variety of

organisms at multiple trophic levels in Lake Superior (Kucklick and Baker 1998). For example, Dykstra

et al. (1998) measured DDE concentrations in nestling blood (1989-1994) and addled eggs (1986-1993)

of bald eagles in Lake Superior and inland Wisconsin sites. A comparison to published and unpublished

historical data indicated that DDE levels declined significantly between 1969 and 1993, with current

levels below those known to result in reproductive impairment.

In a study of juvenile American alligators in Lake Apopka, Florida, p,p’-DDE was detected in

female serum at 17.98 ± 5.3 (SEM) ng/mL and in male serum at 7.35 ± 2.4 (SEM) ng/mL. Serum

concentrations were significantly higher in females than males. Both male and female alligators in this

area have been associated with abnormal reproductive and endocrine functions (Guillette et al. 1999).

In a sediment contamination study of the Chesapeake Bay and its tributaries from 1984 to 1991

by Eskin et al. (1996) under the Chesapeake Bay Program, concentrations of DDT and its metabolites

tended to decline from the head to the mouth of the mainstem bay. Highest concentrations (0.0016 ppm

DDT and 0.0023 ppm DDE) were detected in sediments in the upper half of the bay and near the mouths

of the York and Potomac Rivers. Elsewhere in the lower half of the bay, concentrations were generally

below detection limits. All DDT sediment concentrations were below the aquatic biota PEL of 0.270

ppm and the aquatic biota NOEL of 0.0045 ppm. DDE sediment concentrations were below the aquatic

biota PEL of 0.130 ppm at all locations, but maximum concentrations exceeded the DDE NOEL of

0.0017 ppm for aquatic biota in some locations in the upper bay. In the tributaries, concentrations were

generally below the PELs for aquatic biota.

Dieldrin. Recent monitoring data from IADN indicate that dieldrin is being transferred out of

the Great Lakes with volatilization from Lake Superior, Lake Erie, and Lake Ontario at 5.9, 6.7, and 6.6

times the loadings in 1994 (Hoff et al. 1996). In general, concentrations of dieldrin in precipitation

decreased from 1986 to 1994, but concentrations were three to four times higher at the Lake Erie site

than at the other sites due to higher usage rates in the surrounding agricultural areas. Higher wet

deposition levels were also observed over Lake Michigan due to the greater degree of urbanization

surrounding that lake (U.S. EPA 1998l). In Chesapeake Bay sediments between 1984 and 1991, dieldrin

was detected at one site at levels between the aquatic biota PEL and NOEL (Eskin et al. 1996).

Chlordane. Chlordane, which was restricted in 1973 to use as a termiticide and was banned in

1988, was used primarily as a pesticide for corn crops (Aigner et al. 1998). Gas phase concentrations of

chlordane in the air over Lake Superior do not currently exhibit a decreasing trend, as has been seen with
Chapter II

Environmental Progress

Page II-66 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

several other banned pesticides. In Chesapeake Bay sediments between 1984 and 1991, maximum

chlordane concentrations were detected at levels between the aquatic biota PEL and NOEL (Eskin et al.

1996).

Toxaphene. In general, historical toxaphene concentration profiles in sediment cores across the

Great Lakes indicate that the onset of contamination was between 1940 and 1950. Maximum levels

occurred in the early 1970s to early 1980s, and accumulation rates in Lake Superior and Lake Michigan

largely declined from historical peaks, as shown by comparing maximum historical rates to present rates

(Table II-25). In addition, Lake Ontario and Lake Superior may have received toxaphene from nonatmospheric sources in the past (Pearson et al. 1997b). A back trajectory analysis using IADN

monitoring data indicates that the Great Lakes receive toxaphene via atmospheric deposition from

sources outside of the Great Lakes basin (U.S./Canada IADN Scientific Steering Committee 1998). 

Pearson et al. (1997b) investigated the history of toxaphene concentrations and accumulation in dated

sediment cores from Lakes Superior, Ontario, and Michigan and two control lakes near Lake Superior

that receive toxaphene only via atmospheric deposition. Concentrations at the surface of the cores,

which represent current contamination levels, were similar among all samples with the exception of two

samples from northern Lake Michigan. The similar toxaphene concentrations among the Great Lakes

cores and control lakes suggest atmospheric input is the dominant source of toxaphene to the Great

Lakes. The higher concentrations in the surface of the two northern Lake Michigan cores indicates that

this area may be receiving current inputs (as great as 30-50 percent) from non-atmospheric sources. 

Table II-25

Current and Maximum Rates of Toxaphene Accumulation in Great Lakes Sediments a

Location Number of Sediment

Cores Analyzed

Accumulation Rates in Sediment 

(ng/cm2/yr)

Present Maximum Historical

Lake Superior 3 0.097 - 0.14 0.25

Northern Lake Michigan 3 0.52 - 1.01 1.07

Southern Lake Michigan

near Chicago Urban Area 1 0.24 0.32

Lake Ontario 3 0.39 - 0.60 1.4

 

a

 All accumulations are focus-corrected.

 Source: Pearson et al. 1997b

Hexachlorocyclohexanes. The "-HCH and (-HCH isomers are Great Waters pollutants of

concern, whereas $-HCH (i.e., another of the eight HCH isomers) is not. Both "-HCH and (-HCH can

be transformed into $-HCH, which is a more toxic and bioaccumulative HCH isomer. Monitoring data

indicate that air concentrations of HCH are decreasing, but the atmosphere continues to be a large source

of HCHs to the Great Lakes. Since the 1980s, "-HCH and lindane ((-HCH) precipitation concentrations

declined; however, between 1991 and 1994, lindane concentrations increased at Lakes Superior and

Ontario, possibly simply due to data variability. Although dry deposition inputs of HCH are relatively

small (e.g., ranging from 0.2 to 1.5 kg/yr in all but Lake Ontario), the 1994 estimates of dry deposition

are three to 10 times higher than 1992 estimates. Wet deposition, which is generally uniform across the

lakes, ranges from 46 to 170 kg/yr and is between 0.25 and 1.2 times 1992 estimates, indicating a general

downward trend in wet deposition. A gradient of "-HCH exists, with higher loadings in the lower lakes

than in Lakes Superior and Michigan. Lindane has the highest wet deposition inputs over Lake Huron,

possibly due to a source in upper Michigan (U.S. EPA 1998l).
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-67

The net gas flux of HCH ranges from -140 to +1200 kg/yr (where positive values indicate

volatilization out of the lake) based on monitoring studies. Both Lake Michigan and Lake Ontario are

saturated with "-HCH (Hoff et al. 1996). For example, the mass of "-HCH lost through air-water gas

exchange in Lake Ontario is similar to major input and loss factors such as wet deposition and advection

(i.e., transport of the pollutant out of the lake) (Ridal et al. 1997). The IADN monitoring data also

indicate that total HCHs are in equilibrium with the surface water and the atmosphere in the Great Lakes

(Hillery et al. 1997). 

Hexachlorobenzene. In general, levels of atmospheric deposition of HCB has remained

constant over the past few years. Cohen et al. (1995) used the HYSPLIT/TRANSCO computer program

to determine the amount of HCB emitted from sources to air and water media that is deposited in the five

Great Lakes. The model was run using 1993 source and emissions data from 1,329 identified sources in

the U.S. and Canada. Table II-26 provides modeled air deposition estimates, average depositional flux,

and water effluent inputs for the five Great Lakes. The results indicate the following.

C The depositional flux of HCB to the lakes increases from Lake Superior, Lake Michigan, Lake

Huron, Lake Erie, to Lake Ontario, following the trend in industrialization around the lakes. 

C Hexachlorobenzene inputs from air deposition are greater than water discharge inputs for Lake

Superior, Lake Michigan, and Lake Huron. In Lake Ontario and Lake Erie, the opposite is true;

however, the estimates for air deposition and waterborne inputs are uncertain for HCB because

sources outside the U.S. and Canada were not considered in the model and because estimates

represent the amount of HCB that would be deposited if the lakes were uncontaminated with

HCB (Cohen et al. 1995).

Table II-26

Modeled Air Deposition, Depositional Flux, and Waterborne Inputs 

of HCB to the Great Lakes

HCB Superior Michigan Huron Erie Ontario Total

Total Deposition (kg/yr)

(range)

11

(4-49)

15

(5-73)

16

(6-74)

15

(6-65)

23

(9-101)

79

(30-362)

Depositional Flux (g/km2/yr) 0.13 0.26 0.27 0.58 1.19 0.32

Waterborne Inputs (kg/yr) 0.1 0.8 0.6 <72 35 <108.5

Source: Cohen et al. 1995

In general, based on IADN monitoring data, wet and dry deposition of hexachlorobenzene (HCB)

to the Great Lakes did not change from 1992 to 1994. In Lake Ontario, however, wet deposition of HCB

increased six times in 1994 over the 1992 estimate. Hexachlorobenzene is in near equilibrium with the

atmosphere and surface water, but is slightly loading Lake Superior and Lake Michigan and slightly

volatilizing from Lake Erie and Lake Ontario (Hoff et al. 1996). 

CROSS-POLLUTANT TRENDS

The EPA and other groups have initiated programs and projects to collect and compile

information to assess current sources, emissions, loadings, exposure, and effects of pollutants in the

Great Waters. Because many of these programs and projects address multiple pollutants of concern and
Chapter II

Environmental Progress

Page II-68 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Types of Fish Advisories

States, including the four U.S. Territories and tribal

governments, issue advisories for waterbodies in an

effort to reduce health risks associated with exposure

to pollutants in certain freshwater fish and shellfish

species:

[ Advisories to limit consumption – advisories to 

 either the general population or subpopulations 

 potentially at greater risk (e.g., children, pregnant 

 or nursing women) to restrict their consumption 

 of specific species of fish and other wildlife.

[ Commercial fishing bans – advisories that prohibit 

 the commercial harvest and sale of fish, shellfish, 

 and/or wildlife species from a designated water 

 body (U.S. EPA 1998k).

present cross-pollutant results, it is more appropriate to present the pollutant-specific information

together with the program background rather than to split the information between pollutant categories. 

Therefore, background information on these various programs or projects along with information on their

results is presented below by program or project. Note that most of these programs and projects are

designed to assess contamination levels in certain media or specific waterbodies. While each program or

project discussed below addresses a Great Waters waterbody and pollutants of concern, these programs

generally do not directly assess atmospheric deposition. Instead, they address general pollution from

many sources, one of which may be the atmosphere. Other programs and initiatives that portray how

EPA and other agencies are working together to address the remaining issues related to atmospheric

deposition of pollutants to the Great Waters are discussed in Chapter III.

FISH CONSUMPTION

ADVISORIES

Fish consumption advisories are means

of limiting human exposure when fish taken from

a particular waterbody contain levels of

pollutants that exceed recommended intake

levels. National and regional trends in fish

advisories can be estimated using EPA’s database

which contains information such as date of

advisory, waterbody name and location, pollutant,

fish or other wildlife species and range, advisory

type, advisory status (e.g., active), and a contact

name and telephone number (U.S. EPA 1998k). 

Note that different sampling methodologies and

different approaches among States and years

makes comparisons among States and years difficult. In addition, the amount of monitoring can vary

widely from State to State.

 In 1997, the number of waterbodies under advisory represented 16.5 percent of the Nation’s

total lake acreage and 8.2 percent of the Nation’s river miles. In addition, 100 percent of the Great Lakes

surface waters and their connecting waters, and a large portion of the Nation’s coastal waters, are under

advisory for one or more Great Waters pollutants of concern. According to the Listing of Fish and

Wildlife Advisories in December 1997, 39 of 56 Great Waters were associated with fish advisories for

pollutants of concern (see Appendix C for details on fish advisories in the Great Waters). The number of

advisories in effect for U.S. waterbodies in 1997 increased 5 percent over the number reported in 1996

and 80 percent over the number reported in 1993 (U.S. EPA 1998k). This increase does not necessarily

reflect actual increases of these pollutants in the environment. Rather, the increase is attributed to an

increase in the number of assessments of contamination levels in fish and wildlife tissues as well as the

use of more rigorous EPA risk assessment procedures by some States to set advisories.

Although advisories in the U.S. have been issued for a total of 46 pollutants, five Great Waters

pollutants – mercury, PCBs, chlordane, dioxins, and DDT – comprised 95 percent of the advisories in

1997 (U.S. EPA 1998k). The number of advisories in the U.S. increased for three of these major

pollutants and decreased for one, specifically:
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-69

C Mercury advisories increased 6 percent (1,677 to 1,782) from 1996 to 1997 and 98 percent from

1993 to 1997 (899 to 1,782). This increase is primarily because of new mercury advisories in 11

States, particularly in Minnesota, Ohio, and Louisiana.

C Advisories for DDT and dioxin rose slightly from 1996 to 1997. Advisories for DDT rose 3

percent (32 to 33), and dioxin advisories rose 8 percent (60 to 65), after a decline in the number

of dioxin advisories in 1996. Dioxin advisories were rescinded in some States, in part, because

many pulp and paper mills changed their processes. However, in Michigan, according to the

1999 Michigan Fish Advisory from the Michigan Department of Community Health, dioxin fish

advisories were expanded to include Lake Huron, Lake Michigan, and Lake Superior. 

C The number of PCB advisories rose 84 percent from 1993 to 1997. In the last year of this period,

however, advisories decreased 5 percent (617 to 588), due primarily to rescinding and

readjusting some previously issued advisories. Despite this recent decline, 30 new advisories

were issued in 1997 -- mostly by Ohio, Maine, Alabama, Connecticut, Minnesota, Nebraska, and

New York – making it difficult to discern trends from these advisories alone.

WATER QUALITY ASSESSMENTS

Surface waters and ground waters throughout the U.S. are monitored regularly to ensure that they

are meeting the water quality standards appropriate to the intended uses. Pollutant concentration levels

are measured to ensure that freshwater sources, including the Great Lakes and Lake Champlain, that are

intended to be used for drinking water do not exceed the maximum contaminant level (MCL) guidelines

for drinking water sources. In other surface waters, including all Great Waters, monitoring is conducted

to ensure that ambient water quality criteria and other relevant guidelines are not exceeded and that the

waterbodies meet the designated uses (e.g., fishing, swimming, boating). The current status of the Great

Waters in terms of water quality criteria is described below.

Drinking Water

Of the Great Waters, only the Great Lakes and Lake Champlain are fresh waters that can be used

as drinking water sources. Data indicate that both of these water systems provide safe drinking water,

particularly as related to the Great Waters pollutants of concern. Based on data from 1994 and 1995

collected in support of section 305(b) of the Clean Water Act (CWA) by States, tribes, and other

jurisdictions, most of the Great Lakes nearshore waters can be used as a source of drinking water with

normal treatment (U.S. EPA 1998n). Similarly, the Lake Champlain Basin Program reported that from

1986 to 1995, only nine violations of EPA drinking water standards were reported – all of which were for

coliform contamination in Vermont (Lake Champlain Basin Program 1999).

Other Water Uses

Data on water quality conditions of the Nation’s waters, including the Great Lakes in particular,

are collected and reported by States, tribes, and other jurisdictions to EPA every 2 years as required

under section 305(b) of the CWA. These assessments are based on water quality data that are compared

to water quality standards, such as designated beneficial uses, numeric and narrative criteria for

supporting each use, and an antidegradation statement to protect existing uses and to protect waterbodies

from deteriorating in quality. Data from 1994 and 1995 indicate that approximately 40 percent of the

Nation’s surveyed rivers, lakes, and estuaries are too polluted to support basic uses, such as fishing and

swimming. Nutrients and metals are the most widespread pollutants impacting lakes and rivers with
Chapter II

Environmental Progress

Page II-70 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Florida NS&T Sites

A recent monitoring study suggests general

decreasing trends in contaminant levels in South

Florida (Cantillo et al. 1997), based on

concentrations of PAH, PCB, DDT, lindane,

hexachlorobenzene, chlordane, lead, mercury, and

cadmium in bivalves from seven South Florida sites

monitored by the NS&T Program during the period

1986 to 1994. Contaminant levels in South Florida

were generally lower than nationwide. Nevertheless,

a recent sediment quality assessment indicates that

resident benthic communities may be adversely

impacted by contaminants at a number of locations in

Tampa Bay (Carr et al. 1996). For instance, up to 73

percent of the sediment pore water samples were

toxic to sediment biota in at least one of the toxicity

tests. In addition, sediment concentrations of several

metals and PAHs were correlated with sediment

toxicity, and concentrations of lead, PAHs, PCBs,

and DDT equaled or exceeded sediment quality

guidelines in several locations. 

agriculture as the most common sources of pollutants; however, atmospheric deposition was also

identified as a source of pollutants. In estuaries, nutrients are the most widespread pollutants with

industrial point sources, urban runoff, and storm sewers as the most common sources of pollutants (U.S.

EPA 1998n).

 

Most of the Great Lakes, in contrast, are safe for swimming and other recreational activities. 

However, approximately 97 percent of the surveyed shoreline area shows unfavorable conditions for

supporting aquatic life and is impacted by toxic organic chemicals that appear in fish tissue samples at

much higher concentrations than in water samples. These impacts are partially due to persistent toxic

pollutant burdens, such as PCBs, in the food web. Several of the Great Lakes States identified air

pollution, discontinued discharges from industrial facilities that are no longer in use, urban runoff and

storm sewers, contaminated sediments, land disposal of wastes, and unspecified non-point sources as

pollutant sources contributing to water quality problems (U.S. EPA 1998n).

NOAA’S NATIONAL STATUS AND TRENDS PROGRAM

Since 1984, NOAA’s National Status and

Trends (NS&T) Program has conducted annual

monitoring of chemical contamination and

biological responses to contamination to

document current conditions and long-term trends

in the environmental quality of U.S. near shore

waters and sediments. The Mussel Watch Project

is a major component of this monitoring program. 

Initiated in 1986, the Mussel Watch Project is

designed to provide long-term trends and largescale monitoring of pollutant distributions, with

an emphasis on temporal rather than spatial

trends. The project tracks trends in pollutant

concentrations in mollusks at 287 coastal and

estuarine sites on the Atlantic, Pacific, and Gulf

coasts (including Great Waters). Eighty-three of

these sites were recently added, including several

sites from the Great Lakes region. Mussels and

oysters are useful for monitoring changes in

pollutant levels because they are sedentary

organisms and concentrations in their tissues

generally reflect changes in the concentrations in the surrounding water. Trends were examined in the

Mussel Watch Project for the following Great Waters pollutants of concern: DDT, chlordane, dieldrin,

PCBs, PAHs, cadmium, lead, and mercury (O’Connor 1999).

Also as part of the Mussel Watch and Benthic Surveillance Projects, NOAA conducts sediment

toxicity assessment studies to determine the extent and severity of sediment toxicity in U.S. coastal

regions. Sediment toxicity studies are conducted based on the following considerations: (1) a high level

of contamination in oysters or mussels sampled in the NS&T Program; (2) the likelihood of adverse

biological effects of contamination based on State and local data; and (3) possible collaboration with

other Federal, State, and local agencies. Since 1991 when NOAA began conducting these studies, 23

coastal bays and estuaries covering approximately 4,000 km2 have been the subject of studies (see text

box). Study sites range in size from 0.3 km2 to 1,350 km2. Sediment toxicity surveys include three

different toxicity tests which measure different biological endpoints leading to different results: (1) the
Chapter II

Environmental Progress

4 Areas with “high” concentrations were identified based on concentration distributions. “High”

concentrations were defined as those with logarithmic values greater than the mean logarithmic value for all

concentrations plus one standard deviation. Therefore, about 15 percent of all concentrations were “high.” 

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-71

amphipod survival test using whole sediment; (2) the sea urchin fertilization test using sediment

porewater; and (3) the Microtox test which measures decreased light production by a luminescent marine

bacterium, Vibrio fischeri, using an organic extract of the sediment. The concentration of approximately

80 chemical contaminants, including mercury, lead, cadmium, PAHs, chlorinated dioxins and

dibenzofurans, DDT and its metabolites, dieldrin, chlordane, lindane, HCH, and HCB, are measured in

sampled sediments. Results of these studies are discussed below (NOAA 1999). 

National Trends

Data collected between 1986 and 1996 from the Mussel Watch Project indicate that

concentrations of most of the Great Waters pollutants of concerns in mussel and oyster tissues are

decreasing at some sites. Specifically, decreasing trends of DDT, chlordane, dieldrin, PCBs, and

cadmium were evident. Concentrations of cadmium declined despite the fact that other trace metals,

including mercury and lead, exhibited no overall trend during this period. Data for PAHs also indicated

no overall trend. Lindane and hexachlorobenzene were so infrequently detected that no trend

determinations could be made. Another study found a decreasing trend for cadmium and lead, and no

overall trend for PAHs (Lauenstein and Daskalakis 1999, O’Connor 1999, NOAA 1998).

The NOAA analyzed spatial trends in sediment contamination based on data collected for the

Benthic Surveillance Project and the Mussel Watch Project (NOAA 1998), and found that both trace

metal and organic contamination are associated with urban areas. Sites with “high” levels of

contamination were located in urbanized areas of the Northeast, San Diego, Los Angeles, and Seattle.4 

The cut-off levels that indicated “high” concentrations for DDT, PCBs, chlordane, dieldrin, PAHs,

mercury, cadmium, and lead are 140 ppb, 430 ppb, 34, ppb, 9.1 ppb, 1100 ppb, 0.23 ppm, 6.2 ppm, and

4.8 ppm (mussels) and 0.84 ppm (oysters), respectively. “High” concentrations were rare in the

southeast and along the Gulf of Mexico. Most sites with “high” contaminant concentrations can be

linked to anthropogenic sources. Tissue concentration data can be misleading, however, because in some

areas natural background levels and characteristics of chemicals can result in higher tissue

concentrations. For example, high concentrations of cadmium and other trace metals in zebra mussels of

the Great Lakes may be due to greater bioavailability of those metals in fresh water (NOAA 1998).

The sediment toxicity surveys, on a national level, indicate that 7 percent of the sediment in all of

the study area was toxic based on the amphipod survival test; 39 percent was toxic based on the sea

urchin fertilization test; and 66 percent was toxic based on the Microtox luminescence test. In general,

larger estuaries and bays (areas greater than or equal to 250 km2 or 100 mi2) had a lower average spatial

extent of sediment toxicity (i.e., 6 percent) as compared to smaller estuaries and bays (i.e., 10 percent). 

However, sediment toxicity varies considerably among study areas in terms of spatial extent and severity

of toxicity. Furthermore, based on amphipod survival tests, NOAA found that the spatial extent of

toxicity was about 35 percent in small urbanized estuaries in the Northeast and southern California and

was only 3 percent in southeastern estuaries, which border coastlines, farms, forests, wetlands, and fewer

industrialized areas (NOAA 1999).
Chapter II

Environmental Progress

Page II-72 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Trends in Great Waters

Pollutant trends based on mussel and oyster tissue data collected for the Mussel Watch Project

from 1986 to 1996 at several Great Waters sites are shown in Table II-27 (NOAA 1998). Similar trends

were also reported in the Second Report to Congress (U.S. EPA 1997b). Decreasing trends are

statistically significant (confidence level of 95 percent); however, quantitative information regarding the

changes in pollutant levels was not provided. Therefore, the magnitudes of the increases or decreases

cannot be compared between sites. 

Table II-27

Trends of Pollutant Concentrations in Mussel Watch Project (1986-1996)

Waterbodies

(number of sites

examined)

Contaminant Trend (number of sites affected) a

Mercury Lead Cadmium PCB DDT PAH Chlordane Dieldrin

Chesapeake Bay

(6 sites) ø (6) ø (5)„ (1)

ø (5)

„ (1)

„ (4)

ø (2)

ø (3)

„ (3) ø (6) „ (5)ø (1)

ø (3)

„ (3)

Delaware Bay

(6 sites) ø (6) ø (6) ø (5)„ (1)

ø (5)

„ (1) ø (6) ø (6) ø (4)„ (2)

ø (5)

„ (1)

Long Island Sound

(9 sites) ø (9) ø (8)„ (1)

„ (5)

ø (4)

„ (5)

ø (4)

ø (5)

„ (4) ø (9) „ (6)ø (3) ø (9)

Narragansett Bay

(3 sites) ø (3) ø (2)„ (1) ø (3) ø (3) ø (3) ø (3) ø (3) ø (3)

Tampa Bay

(6 sites) ø (6) ø (5)€ (1) ø (6) ø (6) ø (4)„ (2) ø (6) ø (3)„ (3) ø (6)

Galveston Bay

(6 sites) ø (6) ø (6) ø (6) ø (6) ø (6) ø (6) ø (4)„ (2)

ø (4)

„ (2)

a

 Sites were sampled in at least 6 of 10 years; trend indicated by arrow (i.e., „ = decreasing trend; € = increasing

trend; ø = no trend). Number of sites showing trend within each waterbody is indicated in parentheses.

Source: NOAA 1998

In Tampa Bay, specifically, NS&T chemical contamination data for sediments, bivalves, and

fish through 1991 indicate that there is not a bay-wide pattern of increasing or decreasing concentrations

over recent years. However, increases and decreases were observed in some sample locations. Local

geographic contamination trends indicate that sediment toxicity is highest in regions of northern

Hillsborough Bay and moderate in regions of western Old Tampa Bay, along the western shore of Middle

Tampa Bay, and in lower Boca Ciega Bay. The least toxic or nontoxic samples were taken from portions

of Old Tampa Bay, and Middle and Lower Tampa Bay. Relatively high concentrations of petroleum

hydrocarbons, chlorinated pesticides, other chlorinated hydrocarbons, ammonia, and trace metals were

detected in the most toxic samples (Long and Greening 1999).

In the Chesapeake Bay, NS&T Program data from 186 sites from 1986 through 1995 generally

indicate no trend in contamination levels in mollusks for each chemical analyzed. However, when trends

were detected, decreases greatly outnumbered increases. Specifically, contamination levels decreased for

chlordane, DDT, and dieldrin (Cantillo et al. 1998). 

Consistent with trends on a national level, most of the Great Waters sites do not exhibit a

statistically significant trend or change in pollutant levels in mollusk tissues during the 10-year period. 

Trends, when present, were mainly decreasing since 1986 (i.e., for cadmium, PCBs, DDT, PAHs,
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-73

chlordane, and dieldrin). According to O’Connor (1999) and NOAA (1998), decreases in levels of these

chemicals are probably the result of bans on the use of chlorinated hydrocarbons (e.g., chlordane, DDT,

PCBs) and the reduced use of certain chemicals.

NATIONAL SEDIMENT QUALITY SURVEY

The National Sediment Quality Survey (NSQS) describes the accumulation of chemical

contaminants in the Nation’s rivers, lakes, estuaries, and coastal waters. The NSQS is the first of three

volumes of the first biennial Report to Congress on the Incidence and Severity of Sediment

Contamination in the United States (U.S. EPA 1997i). The NSQS includes a screening-level assessment

comparing human and ecological health benchmarks (e.g., draft sediment quality criteria, EPA cancer

and noncancer human health risk levels) to concentrations of contaminants in sediment or, for human

health only, to actual or estimated fish tissue concentrations. Results indicate the following.

C About 5 percent (i.e., 96) of the Nation’s watersheds include APCs (Figure II-17, Appendix D

includes the names of the numbered sites). The watersheds of the Great Lakes, Chesapeake Bay,

and at least 17 NEP and NERRS sites are associated with APCs. An additional 39 percent of

watersheds include at least one sampling station where contamination levels suggest probable

adverse effects. Among that 39 percent are the watersheds of the Great Lakes, Chesapeake Bay,

Lake Champlain, and some coastal waters. Only about 6 percent of watersheds did not indicate

potential adverse effects on aquatic life or human health. Although there were no contaminant

data for 35 percent of the watersheds, the data used were from monitoring programs targeted to

areas with known or suspected contamination.

C Probable aquatic life impacts were observed 41 percent more frequently than probable human

health impacts. Specifically, of the 21,096 sites sampled, 3,287 had probable aquatic life impacts

and 2,327 had probable human health impacts. 

C The contaminants detected most frequently at levels indicating probable adverse effects include

PCBs, mercury, pesticides, and PAHs. Polychlorinated biphenyls were the sole or among the

responsible indicators at 58 percent of the most contaminated (i.e., probable effects) sampling

stations. Non-mercury metals were solely responsible for about 6 percent of the most

contaminated sampling stations and 28 percent of the moderately contaminated (i.e., possible

effects) sampling stations.

CHESAPEAKE BAY PROGRAM

As part of the Chesapeake Bay Program and in support of the goals and commitments of the

Chesapeake Bay Agreement, information has been collected to assess the progress that has been made in

reaching those goals. 

C A recent analysis of 10 years of monitoring data indicates that the water quality of major rivers

and freshwater portions of the bay has improved, probably due to reduced runoff from

agricultural lands, the phosphate detergent ban, and point source reductions in phosphorous and

nitrogen releases (e.g., at wastewater treatment facilities) (Chesapeake Bay Program 1998d). 

• The amount and extent of submerged aquatic vegetation (SAV) is a good indicator of water

quality in the Chesapeake Bay. Although the areal coverage of bay grasses, or SAV, increased

by 9 percent to 69,238 acres in 1997, in 1998 the acreage had decreased by 8 percent to 63,496
Chapter II

Environmental Progress

Page II-74 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure II-17

Locations of Areas of Probable Concern Within Watersheds

See Appendix D for names of numbered sites.

Source: U.S. EPA 1997i
Chapter II

Environmental Progress

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page II-75

acres. The reasons for the 1998 decrease are unclear, but higher-than-average flow conditions in

1998 are a likely factor. Even so, the total acreage of SAV in 1998 still represents a 70 percent

increase over the 1984 low point and 56 percent of the goal to restore 114,000 acres of SAV by

2005 (Chesapeake Bay Program 1999b). 

C National Toxics Release Inventory (TRI) data from 1988 to 1997 indicate a 67 percent reduction

in chemical releases and transfers from industrial facilities to the bay. Releases of eight of the

Chesapeake Bay Program Toxics of Concern (several of which are Great Waters program

pollutants of concern), however, increased sharply in 1995, mostly due to the activities of a few

facilities that were responsible for almost half of the releases (Chesapeake Bay Program 1998c).

C From 1985 to 1997, total nitrogen concentrations decreased in the Susquehanna River, which

provides over 50 percent of the fresh water to the bay. Nitrogen concentrations decreased in six

of the major rivers to the bay (i.e., Susquehanna, Patuxent, Rappahannock, Mattaponi, James,

Appomattox) and remained unchanged in two other rivers (i.e., Potomac, Pamunkey (a tributary

to theYork)). In contrast, total nitrogen concentrations increased in the upper central portion of

the bay (i.e., the region around the Patapsco and Chester rivers) (Chesapeake Bay Program

1998b). 

LAKE CHAMPLAIN SEDIMENT TOXICS ASSESSMENT PROGRAM

Phase II of the Lake Champlain Sediment Toxics Assessment Program investigated the three

most contaminated areas of the lake: Cumberland Bay, Burlington Harbor, and Malletts Bay (McIntosh

et al. 1997). Sediments of Cumberland Bay at Plattsburgh, New York are contaminated with PCBs from

local historical sources and a possible source entering from the Saranac River. Water column

concentrations in Cumberland Bay generally range from 0.3 to 2.1 ng/L, approximately an order of

magnitude higher than in the main portion of the lake which has concentrations similar to present day

levels in the Great Lakes. Water column concentrations of PCBs decreased dramatically with distance

from the PCB “hot spot” near Wilcox Dock. Maximum concentrations near Wilcox Dock are up to 41

ng/L or 100 times greater than levels in the main body of the lake (McIntosh et al. 1997). The New York

State Department of Environmental Protection recently completed a cleanup plan for Cumberland Bay,

which will remove the most contaminated sediment near Wilcox Dock.

Surface sediment analyses at Burlington Harbor reveal that cadmium, copper, chromium, lead,

and zinc display no clear spatial distribution, suggesting non-point sources (e.g., storm water,

atmospheric deposition) for these metals. Bioavailability of metals appears to vary seasonally. Organic

contaminants in Burlington Harbor (including PCBs, PAHs, and selected pesticides) generally exceeded

the low estimate of sediment contamination levels at which adverse effects are predicted to occur among

sensitive species or sensitive life stages. The PAHs and DDE exceeded the estimate of the sediment

concentration levels at which toxic effects are predicted to occur among most species. Toxicity tests and

benthic community analyses in Burlington Harbor showed chronic toxicity for a limited number of

species, but the harbor does not appear to exhibit widespread hazardous conditions for aquatic life. In

outer Mallets Bay, sediments frequently exceeded severe effects levels for some metals; however,

mercury, lead, and cadmium were not the responsible contaminants (McIntosh et al. 1997).
Chapter II

Environmental Progress

Page II-76 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

SAN FRANCISCO ESTUARY REGIONAL MONITORING PROGRAM

FOR TRACE SUBSTANCES

The San Francisco Estuary Regional Monitoring Program for Trace Substances began in 1993,

and results are available from monitoring through 1996. This program collects data on water, sediment,

and tissue contamination levels for a variety of pollutants, including some Great Waters pollutants of

concern. Analyses of water column concentrations indicate that PCBs, PAHs, certain chlorinated

pesticides, and mercury exceed water quality criteria (Table II-28). In sediments, mercury, total DDTs,

and dieldrin frequently exceed levels at which adverse ecological effects are possible. An analysis of

contaminant bioaccumulation by bivalves indicates that PCBs and PAHs are above the maximum tissue

residue levels (MTRLs, relatively recently developed, science-based guidelines). Polychlorinated

biphenyls, dioxin, mercury, dieldrin, DDT, and chlordane concentrations in fish tissue exceed EPA

screening values for human consumption. Lead levels are usually below water and sediment quality

guidelines and have not shown evidence of bioaccumulation or biological effects. In comparing data

over several years, concentrations of mercury, lead, and chlordane are decreasing in tissues. Overall, the

condition of the San Francisco estuary seems to be improving over time. Additional trends analyses will

be conducted as additional data are collected (San Francisco Estuary Institute 1997). 

Table II-28

Percentages of 1996 Samples that Exceeded Guidelines

in the San Francisco Estuary

Pollutant Water (Dissolved) Water (Total) Sediment Bivalve Tissue

Cadmium 0 0 0 --

Mercury 0 19 81 0

Lead 0 6 6 --

PCBs NA 93 6 100

PAHs NA 0 38 100

Chlordane NA 12 31 89

Dieldrin NA 8 68 78

p,p’-DDE NA 16 71 15

-- = no consistent guidelines

Source: San Francisco Estuary Institute 1997
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-1

State, Local, and Tribal Activities .......... III-51

<State and Local Activities ................. III-51

<Tribal Activities ........................ III-60

Industry Activities ...................... III-63

<Chlor-alkali Industry Mercury Reduction Goal III-63

<Voluntary Mercury Agreement with Northwest

Indiana Steel Mills .................... III-64

<American Hospital Association MOU ....... III-64

<Electric Power Research Institute Studies .... III-65

Work With Other Countries .............. III-66

<Canada-U.S. Binational Toxics Strategy ..... III-66

<International Joint Commission ............ III-69

<LRTAP Protocol on Heavy Metals and POPs . III-70

<UNEP Global POPs Initiative ............. III-71

<NAFTA Commission on Environmental 

 Cooperation .......................... III-71

<U.S.-Canada Air Quality Agreement ........ III-72

National Programs and Activities ............. III-3

<Multimedia Activities ........................ III-4

<HAP Controls ............................. III-11

<Stationary Source Controls Addressing NO x..... III-17

<Mobile Source Program Activities ............. III-29

<Ozone and PM NAAQS ..................... III-30

<Other National Programs .................... III-30

Regional and Waterbody-specific Programs ... III-34

<Great Lakes Program ....................... III-35

<Lake Champlain Basin Program ............... III-37

<Chesapeake Bay Program .................... III-38

<Gulf of Mexico Program .................... III-41

<National Estuary Program ................... III-42

<NOAA Activities .......................... III-48

<Ozone Transport Commission ................ III-49 USDA Natural Resources Conservation Service, Romy Myszka

CHAPTER III

MAJOR PROGRAMS AND ACTIVITIES

This chapter summarizes major programs and activities undertaken or completed since the

Second Great Waters Report to Congress. All of these programs and activities are helping to address

issues relevant to the Great Waters program. The focus of this chapter primarily is on regulatory and

policy initiatives as opposed to new science or research, which is covered in Chapter IV. Although some

of the programs and activities described are being performed in conjunction with the EPA’s Great Waters

program, most are not. Many of the activities are led by partners outside the EPA, and have been

included because they contribute to emission reductions and loadings of Great Waters pollutants of

concern. 
Chapter III

Major Programs and Activities

Page III-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

5

5

5

5

5

5

There are more than 60 programs in progress, described in this chapter, that directly or indirectly address issues

of concern to the Great Waters.

Programs described in this chapter reduce the use of Great Waters pollutants of concern, reduce emissions of

pollutants, restore (e.g., by sediment remediation) the Great Waters where they have been impacted, mitigate

(e.g., by reducing consumption of contaminated fish) human health or ecological effects of Great Waters

pollution, and provide a better scientific understanding of the sources, processes, and effects of and solutions to

atmospheric deposition.

Essentially all of EPA’s Program Offices and most Regional Offices are involved in national, regional, or

waterbody-specific activities addressing Great Waters issues.

 The EPA activities affecting Great Waters issues are performed under EPA’s traditional media- and statutespecific programs (e.g., CAA programs) and under Agency-wide and inter-program multimedia initiatives (e.g.,

the Persistent Bioaccumulative Toxics Initiative (PBTI), Clean Water Action Plan).

In addition to EPA, numerous other parties (including other Federal agencies; municipal, State, tribal and

international governing bodies; the private sector; and, academic researchers) are leading programs which

address Great Waters issues and pollutants of concern.

The majority of the programs and activities described in this chapter involve collaborative partnerships, and

many use community-based approaches to address local environmental priorities that are also Great Waters

issues.

CHAPTER 3 HIGHLIGHTS
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-3

III.A NATIONAL PROGRAMS AND ACTIVITIES

A number of EPA’s national programs and activities contribute to understanding and reducing

pollutant impacts on the Great Waters. As discussed in Section I.B, most of the Great Waters pollutants

of concern are also the focus of other national programs and activities. These programs and activities

protect and enhance the quality of surface waters throughout the U.S., including the Great Waters. 

Recent accomplishments of these other programs and activities are summarized below, organized by

whether they are considered multimedia activities, HAP-specific controls, mobile source program

activities, or other national programs.
Chapter III

Major Programs and Activities

Page III-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Guiding Principles for PBT Initiative

5 Address problems on multimedia basis through 

 integrated use of all EPA tools

5 Coordinate with and build on relevant 

 international efforts

5 Coordinate with relevant Federal programs and 

 agencies

5 Stress cost-effectiveness

5 Involve stakeholders

5 Emphasize innovative technology and pollution 

 prevention

5 Protect vulnerable subpopulations

5 Base decisions on sound science

5 Use measurable objectives and assess 

 performance

Binational Toxics Strategy - Level I Substances

Aldrin/dieldrin*

Benzo(a)pyrene*

Chlordane*

DDT (DDD/DDE)*

Hexachlorobenzene*

Alkyl lead*

Mirex

Mercury and

compounds*

Octachlorostyrene

PCBs*

Dioxins and furans*

Toxaphene*

*Great Waters pollutants of concern

MULTIMEDIA ACTIVITIES

Persistent Bioaccumulative Toxics Initiative

The Persistent Bioaccumulative Toxics Initiative (PBTI) which was developed in an EPA-wide

effort chaired by the Office of Prevention,

Pesticides and Toxic Substances (OPPTS),

supports Great Waters program goals by helping

to reduce environmental releases of certain Great

Waters pollutants of concern. The goal of the

PBT Initiative is to further reduce risks to human

health and the environment from existing and

future exposure to persistent, bioaccumulative,

and toxic (PBT) pollutants. The initiative seeks to

accomplish this goal through increased

coordination among EPA national and regional

programs with the significant involvement of

international, State, local, and tribal organizations,

the regulated community, environmental groups,

and private citizens. This effort fortifies existing

EPA commitments related to priority PBTs, such

as the 1997 Canada-U.S. Binational Toxics Strategy (BNS), the North American Agreement on

Environmental Cooperation, and EPA’s Clean Water Action Plan (see below for more information on

these activities). 

The PBT Initiative initially will focus on the 12 priority pollutants identified under the

Binational Toxics Strategy (BNS) (see sidebar below). The initiative includes the following steps:

1. Develop and implement national action

plans for priority PBT pollutants. Nearterm activities include pollution

prevention projects, enforcement and

compliance assistance, development or

revision of water quality criteria,

research and analysis of emission and

discharge controls and other topics, and

collaboration with other international

efforts beyond the BNS. The draft

Mercury Action Plan has been developed

and includes regulatory and

nonregulatory initiatives.

2. Screen and select more priority PBT pollutants for action. The EPA will apply selection criteria

for additional pollutants in consultation with a technical panel.

3. Prevent introduction of new PBTs. The EPA is acting to prevent new PBT chemicals from

entering commerce by (1) proposing criteria for new PBT chemicals, (2) developing a rule to

prevent re-introduction of phased out PBTs, (3) developing incentives to reward development of
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-5

National Water Quality Inventory

“The final National Water Quality Inventory Report to

Congress for 1996 indicates that of the 72 percent of

estuary waters assessed, 38 percent are not fully

supporting uses/standards and 4 percent are

threatened.” (U.S. EPA 1998o). 

Mercury TMDL Air Deposition Pilot Project

In order to assist States in preparing TMDLs for

waterbodies affected by atmospheric pollutants, the

EPA Office of Water (OW) and Office of Air Quality

Planning and Standards (OAQPS) have initiated the

Mercury TMDL Air Deposition Pilot Project. This

project, a collaborative effort between OAQPS, OW,

the Office of Research and Development, EPA

regional offices and State agencies, will investigate

tools and approaches for developing TMDLs in cases

involving atmospheric pollutants. The project will

design, develop, and identify uncertainties and data

needs for pilot mercury TMDLs for two waterbodies

receiving mercury contributions from the air. In the

process, the compatibility of air and water quality

modeling systems, as well as the linkages between

the CWA and CAA will be evaluated. Two pilot

TMDL waters have been selected for study (Devil’s

Lake, Wisconsin, and the Everglades Conservation

Area 3a, Florida). Modeling work is under way. 

PBT alternatives, and (4) documenting how PBT-related screening criteria are being taken into

account for approval of new pesticides and re-registration of existing pesticides.

4. Measure progress. The EPA is in the process of defining measurable objectives to assess

progress. These could include trend detection in environmental health, direct measurements of

human exposure through biomarkers, tracking of chemical releases to the environment, and

program activity measures such as enforcement actions.

The EPA solicited public comments on a draft PBT Initiative published in late 1998. For further

information on the status of the initiative, see the web page at www.epa.gov/pbt/strtegy.htm.

Total Maximum Daily Loads

Under the Federal Clean Water Act of 1972 (CWA), EPA is required to develop effluent

guidelines for specific categories and classes of point sources. The guidelines are used to set discharge

limits for specific facilities that discharge pollutants to surface waters or to municipal sewage treatment

systems (63 FR 22644, April 27, 1998). However,

many U.S. waterbodies do not meet applicable

water quality standards, which include standards

for many Great Waters pollutants of concern,

despite the implementation of the CWA (see

sidebar), in part because of non-point source

pollution, including atmospheric deposition. Total

maximum daily loads established under section

303(d)(1) of the CWA, provide a framework for

addressing pollution from both point and non-point sources. A TMDL is developed for a waterbody if

water quality standards within the waterbody are not being met using technology-based or other effluent

controls. A TMDL establishes the maximum allowable pollutant loading for a waterbody (including

allocations for point source loads and non-point source loads, and a margin of safety) that will result in

the waterbody meeting established water quality standards. Specifically, TMDLs assess non-point

source loads, such as atmospheric deposition, in addition to point source inputs. In some cases, TMDLs

attempt to identify the source of atmospheric

deposition in order to implement appropriate

measures to decrease the pollutant inputs to a

watershed. In terms of atmospheric deposition,

EPA is developing science and tools to assess the

contribution of atmospheric sources to water

pollution and to assist in decreasing total

pollutant loadings to waterbodies.

As required by the CWA, States are

directed to identify and directs States to identify

and establish a priority ranking for waters that do

not meet applicable water quality standards after

application of technology-based and other

controls, taking the severity of the pollution and

the designated uses of the waterbody into

consideration. The EPA’s implementing

regulations require States to submit these lists

every 2 years. Once the list of priority waters is
Chapter III

Major Programs and Activities

Page III-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

approved by EPA, the State establishes TMDLs for each waterbody on the list to restore water quality. 

The TMDL specifies the amount of pollution or other stressor that needs to be reduced to meet water

quality standards, allocates pollution control or management responsibilities among sources in a

watershed, and provides a scientific and policy basis for taking actions needed to restore a waterbody

(U.S. EPA 1998o). A TMDL may also identify the need for point source or non-point source controls. 

The EPA recently began development of a TMDL pilot project addressing atmospheric deposition of

mercury (see sidebar).

A variety of tools have been created to assist States in the process of developing TMDLs. Many

of the tools were created in response to challenges encountered in allocating non-point source inputs of

nitrogen compounds to specific land uses. Additional tools have been developed to assist in decreasing

loadings to waterbodies. See, for example, the discussion of the Albemarle-Pamlico Estuary (NC) under

the National Estuary Program in Section III.B. 

Also, to assist in the implementation of TMDLs in States, EPA published a report, TMDL

Development of Cost Estimates: Case Studies of 14 TMDLs (U.S. EPA 1996b). The selected TMDL case

studies are from a variety of geographic locations, address the most common pollutants, range from

small- to large-scale projects, and represent a range of complexity levels. The report also identifies

funding sources and discusses benefits of TMDLs (U.S. EPA 1998v). 

Pulp and Paper Cluster Rule

In April 1998, EPA promulgated the pulp and paper cluster rule – a joint CAA and CWA rule –

which is designed to protect human health and the environment by reducing releases of toxic pollutants

from the pulp and paper industry to air and water. This rule is the first integrated regulation to control

the release of pollutants to more than one media from one industry. Implementation of the rule will

further reduce paper industry air emissions and surface water discharges of certain Great Waters

pollutants of concern (e.g., dioxins and furans).

By issuing joint standards, industry can consider all regulatory requirements at one time;

therefore, reducing the regulatory burden and allowing mills to select the best combination of pollution

prevention and control technologies that will provide the greatest protection to human health and the

environment. The cluster rule requires new and existing pulp and paper mills (1) to capture and treat

toxic air pollutant emissions that occur during cooking, washing, and bleaching stages of the pulp

manufacturing process and (2) to meet new effluent limits for toxic pollutants in the wastewater

discharged during the bleaching process and in the final discharge from mills in the bleached papergrade

kraft and soda subcategory and in the bleach papergrade sulfite subcategory. The rule limits releases of

toxic air pollutants from processes that are used at 155 of the 565 U.S. pulp and paper mills (i.e., the rule

applies to paper and paperboard mills, also referred to as kraft, soda, sulfite, and semi-chemical mills)

along with water discharges of toxics and other pollutants from the 96 of those 155 mills that bleach pulp

to make paper. The new water limits are based on substituting chlorine dioxide for chlorine in the

bleaching process (63 FR 18504, April 15, 1998). 

The new air and water standards under the pulp and paper cluster rule will provide significant

environmental benefits, including:

C Seventy-three rivers and streams will become cleaner because of toxic release reductions;

C Emissions of over 160,000 tons of toxic air pollutants will be eliminated;
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-7

Clean Water Action Plan: 

Key Actions to Assess and Reduce Air Deposition

of Nitrogen

“EPA and NOAA will work with other Federal, State,

tribal, and local government agencies and others to

better quantify the risks associated with atmospheric

deposition of nitrogen compounds and other

pollutants to waterbodies.”

“EPA will work through the TMDL program to

evaluate the linkage of air emissions to the water

quality impacts to help determine appropriate

reduction actions. EPA will work with States, tribes,

and Federal land management agencies to employ

both Clean Water Act and Clean Air Act authorities to

reduce air deposition of nitrogen compounds and

other pollutants that adversely affect water quality.”

(U.S. EPA 1998a)

C Dioxin and furan discharges to water will be reduced by 96 percent; and,

C Ultimately, all dioxin fish consumption advisories associated with the 96 mills affected by this

action will be eliminated (63 FR 18504, April 15, 1998).

The pulp and paper cluster rule also includes an innovative voluntary incentives program (i.e.,

the Voluntary Advanced Technology Incentives Program). Under this program, mills are voluntarily

subject to more stringent standards in return for rewards, such as increased compliance time, reduced

monitoring requirements and inspections, greater permit certainty, reduced penalties, and public

recognition (63 FR 18504, April 15, 1998). For example, mills participating in the program are allowed

6 years instead of 3 years to comply with air standards and 6 to 16 years to comply with water discharge

permit limits, depending on the performance level of the new technology or process change. This

program also encourages mills to consider all technology options prior to making large investment

decisions, such as purchasing new emissions control devices or implementing major process changes

(U.S. EPA 1997d). In the long term, this innovative program could result in additional reductions in air

toxics releases and water pollutant discharges. 

Mercury Research Strategy

The EPA, in an intra-agency effort led by EPA’s Office of Research and Development, is

developing a Mercury Research Strategy, which is expected to be completed in 2000. The EPA plans for

the strategy to describe:

C The key scientific questions of greatest concern to EPA for mercury risk assessment and risk

management that EPA plans to investigate over the coming 5 years; and, 

C A research program which would provide information, methods, models, and data to address

these key scientific questions.

The research strategy is intended to guide EPA’s development of research plans and decisions about

future research priorities and budgets. It may also provide useful information to others in guiding their

research. However, the strategy is not intended to convey information on specific projects, nor will it

provide a detailed schedule of outputs or

products.

Clean Water Action Plan

Completed in February 1998, the Clean

Water Action Plan is an interagency, multimedia

strategy to address remaining obstacles to the

original goal of the Clean Water Act – “fishable

and swimmable” water for all Americans (U.S.

EPA 1998a). The action plan was requested by

Vice President Al Gore on October 1997 to mark

the 25th anniversary of the Clean Water Act. It

forms the core of President Clinton’s Clean Water

Initiative, which was proposed in the 1998 State

of the Union Address. Together, the Clean Water
Chapter III

Major Programs and Activities

Page III-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Action Plan and Initiative outline specific actions to strengthen and expand efforts to restore and protect

water resources. 

The plan identifies non-point sources (including atmospheric deposition) as the most important

remaining threat to water quality. Because EPA’s existing water programs do not focus on control of

non-point sources, the action plan emphasizes innovative approaches such as partnerships with local

stakeholders and watershed-level projects. Atmospheric deposition is among the leading non-point

sources addressed by the action plan. In particular, agencies pledged to work together to better assess the

risks associated with atmospheric deposition of nitrogen compounds (see sidebar) and other pollutants to

waterbodies and to integrate air deposition into TMDL evaluations. In addition, EPA will include air

deposition in a multiagency coastal research strategy and coordinated coastal monitoring plan, expected

to be issued in 2000.

Another action in the President’s Clean Water Action Plan is to conduct a national survey of

levels of persistent bioaccumulative toxic (PBT) chemical levels in fish and shellfish throughout the

country. Specifically, EPA and NOAA are conducting a study to estimate the national distribution of the

mean levels of selected PBT chemical residues in fish and shellfish tissue in U.S. waters. The study will

provide information for the Agency’s PBT Initiative, which seeks to identify potential areas of concern

for human and/or ecological health. The study of fish tissue may reveal where PBT chemicals not

previously considered a problem are present in the environment at levels of concern. For the national

fish study, fish will be obtained from lakes and reservoirs which have been selected according to a

probability design. The shellfish survey will be based on the data obtained by NOAA’s ongoing Mussel

Watch Project. Both studies will be coordinated with State and tribal efforts to maximize geographic

coverage.

Sediment Quality Report to Congress

Once deposited to surface waters from the air or other sources (e.g., industrial and municipal

point discharges, urban and agricultural runoff), most of the Great Waters pollutants of concern tend to

accumulate in sediments where they may reach concentrations harmful to aquatic life and the food web. 

In recognition of environmental and economic problems associated with contaminated sediment,

Congress included in the Water Resources Development Act (WRDA) of 1992 a requirement for EPA, in

cooperation with NOAA and the U.S. Army Corps of Engineers, to conduct a comprehensive national

survey of data regarding the quality of aquatic sediments in the U.S.

In September 1997, EPA’s Office of Science and Technology within the Office of Water

published the first biennial Sediment Quality Report to Congress, entitled the Incidence and Severity of

Sediment Contamination in the Surface Waters of the United States. The report consisted of three

volumes:

Volume 1: The National Sediment Quality Survey (U.S. EPA 1997i);

Volume 2: Data Summaries for Areas of Probable Concern (U.S. EPA 1997j); and,

Volume 3: The National Sediment Contaminant Point Source Inventory (U.S. EPA 1997k).

The National Sediment Quality Survey (NSQS) (U.S. EPA 1997i) describes the accumulation of

chemical contaminants in river, lake, ocean, and estuary bottoms and includes a screening assessment of

the potential for associated adverse effects on human and environmental health. Key findings of the

NSQS are discussed in Chapter II.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-9

In developing the NSQS, EPA compiled all available computerized data on the quantity,

chemical and physical composition, and geographic location of pollutants in sediment. The database is

referred to as the National Sediment Inventory (NSI) and is the largest set of sediment chemistry and

related biological data ever compiled by EPA. The NSI will be updated on a regular basis in order to

assess trends in both sediment quality and the effectiveness of existing regulatory programs at the

Federal, State, and local levels. The NSI is discussed further in Chapter IV.

The EPA’s mandate to investigate sediment contamination in the Nation’s water included a

directive to identify potential pollutant sources. Volume 3 of the Sediment Quality Report to Congress

(U.S. EPA 1997k) evaluated point sources (i.e., direct discharges to waterbodies). In future biennial

Reports to Congress, EPA will assess loadings from non-point sources, including harvested croplands,

urban areas, atmospheric deposition, and abandoned and inactive mine sites (U.S. EPA 1997i). To

prepare the non-point source inventory for the second Sediment Quality Report to Congress, EPA is

currently compiling data from the Bureau of the Census, the U.S. Department of Agriculture, the U.S.

Department of the Interior’s U.S. Geological Survey and Bureau of Mines, and others. 

Contaminated Sediment Management Strategy

The EPA is using data compiled for the Sediment Quality Report to Congress and other resources

for a multiprogram, multimedia effort to coordinate and streamline contaminated sediment management

decisions within the Agency. In April 1998, EPA’s Office of Water completed the Contaminated

Sediment Management Strategy (U.S. EPA 1998d), which outlines the following specific actions: 

1. Control sources of sediment contamination and prevent the volume of contaminated sediment

from increasing; 

2. Reduce the volume of existing contaminated sediment; 

3. Ensure that sediment dredging and dredged material disposal are managed in an environmentally

sound manner; and, 

4. Develop scientifically sound sediment management tools for use in pollution prevention, source

control, remediation, and dredged material management. 

The Contaminated Sediment Management Strategy identifies atmospheric deposition as an

important source of sediment contamination. Specifically, the strategy directs EPA’s Office of Air and

Radiation to use the National Sediment Inventory (NSI) to evaluate the contribution of atmospheric

deposition to sediment quality problems. This new tool will enable EPA to better assess trends in

sediment pollution, including pollution from atmospheric deposition, and focus cleanup and pollution

control activities. In addition, the strategy identifies the Agency’s Great Waters program as a significant

component of its coordinated effort to address contaminated sediment problems.

The Contaminated Sediment Management Strategy includes a research component designed to

identify relationships between sediment contaminants and the viability and sustainability of benthic

ecosystems. Ultimately, the research will help to formulate source control and pollution prevention

strategies. In addition, the strategy outlines coordinated, multiprogram efforts of research and policy

development to ensure that uniform exposure and effects assessment procedures for contaminated

sediments are used throughout the Agency. For example, EPA proposed, and is currently developing,

standard sediment toxicity test methods and chemical-specific sediment quality guidelines. The strategy
Chapter III

Major Programs and Activities

Page III-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

proposes several specific uses of the assessment procedures and sediment quality guidelines, and the

Agency has begun to develop an Equilibrium Partitioning Sediment Guidelines User’s Guide.

Waste Minimization National Plan

The Waste Minimization National Plan (WMNP), which EPA’s Office of Solid Waste developed

in 1994, is a voluntary, long-term effort to reduce the quantity and toxicity of hazardous waste through

source reduction and recycling, including wastes bearing Great Waters pollutants of concern such as

mercury and dioxin. The plan calls for a 50 percent reduction in the presence of the most persistent,

bioaccumulative, and toxic (PBT) chemicals in hazardous waste by 2005 compared to a baseline year of

1991. This goal was also adopted as a Government Performance and Results Act (GPRA) measurement

goal. 

To assist in implementing the WMNP, the Office of Solid Waste and the Office of Pollution

Prevention and Toxic Substances have developed a draft Windows-based software tool to prioritize PBT

chemicals for waste minimization efforts. The Waste Minimization Prioritization Tool (WMPT)

provides a screening-level assessment of potential chronic risks that chemicals, including most Great

Waters pollutants of concern, pose to human health and the environment, based on their persistence,

bioaccumulative potential, and human and ecological toxicity. More information about the WMPT can

be found on EPA’s waste minimization home page at www.epa.gov/wastemin.

The WMPT served as a starting point in developing the draft Resource Conservation and

Recovery Act PBT Chemicals List (63 FR 60332, November 9, 1998). Other factors, such as quantity,

prevalence, environmental presence, and degree of concern to the RCRA program, were used in the

selection of chemicals for the draft list. The final list of chemicals is expected to be published in the

Federal Register in 2000. This final list will serve to focus national waste minimization efforts and track

progress toward the 2005 reduction goal.

Air Characteristic Study

The Air Characteristic Study currently being conducted by EPA’s Office of Solid Waste

addresses the question of whether some industrial wastes should be classified as hazardous because of

risks posed by their air emissions. The overall goal of this study is to estimate the maximum waste

constituent concentrations that could be present in certain waste management units and still be protective

of human health.

The study is estimating potential risk to humans for 105 chemical constituents, of which 88 are

HAPs under the CAA and several are Great Waters pollutants of concern (e.g., lead compounds,

mercury, benzo[a]pyrene, dioxin, and others). Draft results of the risk analysis indicate that volatile toxic

chemicals managed in non-storage tanks, such as aerated wastewater treatment tanks, pose the highest

risk, with the waste concentrations for these aerated tanks differing from other units by an order of

magnitude or more. Storage tanks, land application units, landfills, and waste piles followed aerated

tanks in ranking of risk. The findings of this study, due to be completed in 2000, will assist EPA in

exploring the need for regulatory changes under RCRA for these waste management units and in

investigating possible options for risk reduction.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-11

HAZARDOUS AIR POLLUTANT (HAP) CONTROLS

Under the CAA, EPA is required to regulate sources of 188 listed HAPs. All but two of the

pollutants identified as Great Waters pollutants of concern are listed as HAPs. (The two Great Waters

pollutants that are not HAPs are nitrogen and dieldrin.) On July 16, 1992, EPA published a list of 174

industry groups (known as source categories) that emit one or more of these air toxics. For listed

categories of “major” sources (those with the potential to emit 10 tons/year or more of a listed pollutant

or 25 tons/year or more of a combination of pollutants), the CAA requires EPA to develop standards

under section 112(d) that require the application of air pollution reduction measures known as MACT. 

This performance-based approach requires EPA to set standards based on consideration of those controls

in use at the best controlled facilities within an industry. 

The CAA provided a 10-year schedule in which to promulgate these technology-based standards

with certain standards being promulgated in the first 2 years, 25 percent in the first 4 years, an additional

25 percent no later than the 7th year, and the remaining 50 percent no later than the 10th year. The EPA

has been productive in fulfilling these statutory requirements and, working in partnership with States, has

built the necessary infrastructure for implementing the air toxics regulations. For the 45 source

categories in the 2- and 4-year groups, EPA estimates that the regulations will reduce air toxics emissions

by approximately one million tons per year. For the 42 source categories in the 7-year group, EPA has

either proposed or promulgated regulations that are estimated to reduce air toxics emissions by roughly

500,000 tons per year. A list of all source categories, the MACT implementation schedule, and

references to proposed and final rules is included in Appendix C of the Residual Risk Report to Congress

(U.S. EPA 1999d).

Some regulations are already in place under section 112(d) with sources currently in compliance. 

The source categories affected by these rules are listed in Table III-1 below along with the emission

reductions of the affected pollutants of concern, where available.

Table III-1

Source Categories With Effective Compliance Dates 

and Anticipated Reductions of HAP Emissions

Source Category Compliance

Date Pollutant

Nationwide

Pre-MACT

Emissions

(tpy) 

Nationwide

Expected

Percent

Reductions 

Coke oven batteries: Charging, leaks,

and bypass/bleeder stacks 01/01/98 Coke ovenemissionsa 1600 94

Secondary Lead Smelting 12/23/97

All HAPsb 1900 65

Lead Compounds 120 40

a

 Coke oven emissions include POM.

b

 HAP emissions for this category include lead compounds, dioxins/furans, mercury, and POM among other

pollutants. Of these, lead compounds is the only pollutant of concern for which pollutant-specific estimates are

available.

Section 112(c)(6) of the CAA directs EPA to focus attention on seven specific toxic pollutants –

all of which are Great Waters pollutants of concern: alkylated lead compounds, hexachlorobenzene,

POM, mercury, PCBs, dioxins, and furans. The Agency is to ensure that sources accounting for at least

90 percent of the emissions of each of these pollutants are subject to standards under section 112(d)
Chapter III

Major Programs and Activities

Page III-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

(described above). Section 112(c)(6) of the CAA requires EPA to identify the source categories that emit

90 percent of the aggregate emissions for each of the seven specific pollutants and add any source

categories not previously identified to the list discussed above.

Under section 112(c)(6), a review of the available data indicated that nearly all source categories

emitting the seven pollutant groups had already been listed for regulation under the CAA or were subject

to comparable regulation under other CAA authorities. However, two additional source categories were

added to the source category list in a final Federal Register notice on April 3, 1998. These two

categories are open burning of scrap tires and gasoline distribution (Stage I Aviation), which includes

evaporative losses associated with the distribution and storage of aviation gas containing lead. A

comment and response document is available along with the 1990 emissions inventory for the seven

pollutants at www.epa.gov/ttn/uatw/112c6/112c6fac.html.

A different section of the CAA (section 129) is devoted to control of certain air toxics, as well as

other pollutants, from solid waste combustion units. The pollutants of concern to the Great Waters

covered are lead, cadmium, mercury, dioxins and furans, and NOx. This regulatory program is discussed

later in this section.

Under sections 112 and 129, several rules have either been proposed or finalized, but the

compliance date has not yet been reached. A summary of these actions and their anticipated emission

reductions are listed below in Table III-2. In addition, under the joint authority of section 112 and the

Resource Conservation and Recovery Act (RCRA), EPA’s Office of Solid Waste finalized on July 30,

1999 (signed by the Administrator) new emission standards for existing and new cement kilns,

incinerators, and lightweight aggregate kilns that burn hazardous wastes. These combustors burn about

80 percent of the hazardous waste combusted annually within the U.S. When fully implemented in 2002,

the MACT standard for these sources is expected to achieve significant reductions in emissions of

several Great Waters pollutants of concern, including dioxin/furans, mercury, lead and cadmium. These

standards will also satisfy our obligation under RCRA to ensure that hazardous waste combustion is

conducted in a manner adequately protective of human health and the environment. 

The remaining 50 percent of MACT regulations are expected to be issued within the next 2 years

(by 2002). Based on our current knowledge of the remaining industries slated for regulation under

section 112(d), those that emit pollutants of concern to the Great Waters include chlorine manufacturing

(chlor-alkali plants), coke ovens (pushing, quenching and battery stacks), industrial boilers, institutional

and commercial boilers, iron and steel, and refractory manufacturing. There are more MACT rules for

solid waste combustion under section 129 noted later in this section.

 In addition to the standards development requirements of the CAA, there are a number of other

HAP program requirements that will help reduce emissions of the Great Waters pollutants of concern. 

These are briefly described below. Additional information regarding the air toxic program can be found

on the Internet at EPA’s unified air toxics web site at www.epa.gov/ttn/uatw. 

Mercury Study Report to Congress

The Mercury Study Report to Congress, issued by EPA in December 1997 (U.S. EPA1997e), is a

comprehensive document detailing the U.S. mercury emissions inventory, fate and transport of mercury

in the environment, human health effects, an ecological risk assessment, a human and wildlife risk

characterization, and an assessment of control technologies and their costs. The report also outlines

research needs. Pertinent results and conclusions from this report are described in the mercury and

compounds section of Chapter 2.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-13

Table III-2

Proposed and Final Rules Affecting Pollutants of Concern

Source Category Status Pollutants

Nationwide

Pre-MACT

Emissions

(tpy)

Nationwide

Expected 

Percent

Reductions

Municipal waste combustion

(large combustors, > 250 tons

per day)

Final rule and guidelines

Dioxins/Furansa 0.0025 98

Mercuryi 54 78

Lead 64 75

Cadmium 4.2 67

NOx 54,000 36

Medical waste incineration Final rule and guidelines

Dioxins/Furansa 0.0002 95-97 b

Mercury 16 93-95 b

Lead 12 80-87 b

Cadmium 1.3 75-84 b

NOx 1,300 0-30 b

Pulp and paper clusterc Final rule HAPs 240,000 58

Primary aluminum production Final rule POM 2,000 50

Secondary aluminum production Final rule

HAP metalsd 64.4 62.5

Dioxins/Furansa 0.0009 86.6

Primary copper production Proposed rule

Cadmium 0 0

Lead 140 13

Mercury 0 0

Pesticide active ingredient

productione Final rule HAPse 4,255 65

Portland cement manufacturing -

nonhazardous waste -fired

Final rule

Dioxins/Furansa 0.0005 36

Mercury 4 0

HAP metalsf

f f

Mineral wool production Final rule HAP metalsg 1.1 91

Hazardous Waste combustion

(existing and new cement kilns,

incinerators, and lightweight

aggregate kilns that burn

hazardous waste) Final rule

Dioxins/Furansa.000044 70

Mercury 6.5 55

Lead and

Cadmium

88.5 88

Other HAP

Metalsh

9.8 75
Chapter III

Major Programs and Activities

Page III-14 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table III-2 (continued)

Proposed and Final Rules Affecting Pollutants of Concern

a Dioxin/Furan emissions are reported on a 2,3,7,8-TEQ basis.

b

 Ranges reflect different assumptions on the number of incinerator closures.

c

 Values represent air emissions affected by the cluster rule only. Values for individual HAPs were not provided in

the final rule.

d

 The HAP metals for secondary aluminum production are mercury, lead, and cadmium, as well as eight other HAP

metals. 

e This rule covers 11 of the source categories listed for regulation. Values for individual HAPs are not available. 

Included are emissions of HCB and chlordane, although they are not the most prevalent HAPs in this category.

f

 The rule includes a particulate matter limit, which serves as a surrogate for all non-volatile and semi-volatile HAPs,

including metals. These metals are estimated to be no more than 1 percent of the total particulate matter HAPs. 

The rule is estimated to achieve about 20 percent reduction in particulate matter emissions.

g The HAP metals for mineral wool production are cadmium and lead, as well as seven other HAP metals.

h

 The other HAP metals for hazardous waste combustion include antimony, cobalt, manganese, nickel, and

selenium.

i

 Emission reductions for municipal waste combustion are often cited from a 1990 baseline, other than the pre-MACT

baseline presented here. For example, the rule and guidelines will reduce mercury emissions by greater than 90

percent from 1990 levels when fully implemented.

The Mercury Study Report to Congress is not a regulatory effort; currently it is being broadly

used in support of Great Waters activities, the PBT Initiative, the Binational Toxics Strategy, the mercury

research strategy, and other EPA efforts to understand and control this pollutant. 

Utility Air Toxics Study and Regulatory Determination

In February 1998, EPA issued a study of the public health impacts of emissions of air toxics from

utilities that burn fossil fuel (U.S. EPA 1998p). About 67 air toxics were found to be emitted from

utilities, including mercury and dioxins. The report includes (1) a description of the utility industry; (2)

an analysis of air toxics emissions data from coal-, oil-, and gas-fired utility plants; (3) an assessment of

risks to public health from exposure to air toxics emissions through inhalation; (4) an assessment of

potential risks to public health from exposure to four specific air toxics (i.e., radionuclides, mercury,

arsenic, and dioxins) through other indirect means of exposure (e.g., food ingestion, dermal absorption);

(5) a general assessment of the fate and transport of mercury through environmental media; and, (6) a

discussion of alternative control strategies.

The report indicates that, although uncertainties in the analysis exist, on balance, mercury from

coal-fired utilities is the HAP of greatest potential public health concern. The report identifies three

other air toxics for which there are some potential concerns and uncertainties that may need further

study: dioxins, arsenic, and nickel. 

The CAA also requires EPA to make a determination, after considering the results of the utility

study, as to whether emission controls for air toxics are appropriate and necessary for utility boilers. The

EPA has delayed this determination until it collects additional information, and EPA’s Office of Air and

Radiation is currently collecting the following mercury emissions data from electric utility steam

generating units:

C Current information on the type of coal they use and on their method of particulate matter (PM)

and sulfur dioxide (SO2) control at all “traditional” coal-fired electric utility steam generating

units;

C Current information on the fuel they use and on their method of PM and SO2 control at all

independent power producers that could be identified as possibly burning coal;
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-15

C 1 year of mercury-in-coal analyses at all coal-fired units meeting the section 112(a)(8) definition

of “electric utility steam generating unit”; and

C One series of speciated mercury emissions testing at a randomly selected subset of coal-fired

units. 

The regulatory determination is scheduled to be provided by December 15, 2000 (U.S. EPA 1998p).

Residual Risk Report to Congress

Under section 112(f) of the CAA, EPA is required to develop and implement a program for

assessing risks remaining (i.e., the residual risk) after facilities have implemented MACT standards, and

to promulgate rules, if necessary, to protect the public health with an “ample margin of safety” or to

prevent adverse environmental effects. Additional risk-based regulations, if needed, are to be

promulgated within 8 years after EPA promulgates an air toxics standard for a given source category. 

The first such risk-based regulations, if necessary, are due in 2002. If promulgated, residual risk

standards could further reduce emissions of Great Waters pollutants of concern. 

In March 1999, EPA issued the Residual Risk Report to Congress. This report reviews EPA

human and ecological risk assessment methods, identifies data sources and data collection needs for

conducting risk assessments, proposes methods on how to close data gaps, discusses how results of

residual risk assessments will be used in the residual risk program, and includes an appendix of all

MACT source categories, the MACT implementation schedule, and references to proposed and final

rules. In addition, the report discusses the strategy or “framework” EPA will use in conducting residual

risk assessments. 

The risk assessment framework under the residual risk program was developed using knowledge

gained from past risk assessments and information from other regulatory agencies and guidance from

reports. This strategy calls for an iterative, tiered assessment of the risks to humans and ecological

receptors through inhalation and, where appropriate, non-inhalation exposures to air toxics. The residual

risk assessment framework will allow the Agency to be flexible in its decisions while ensuring that

public health and the environment are protected. The EPA’s objectives also include integration of all

portions of the Federal air toxics program, continuing the partnership with State/local programs in the

sharing of data and expertise, and including groups who may be affected by residual risk decisions (e.g.,

industry, public interest groups) as part of the process. 

Integrated Urban Air Toxics Strategy and Report to Congress

As part of its overall efforts to reduce air toxics, EPA published the integrated urban air toxics

strategy in the Federal Register on July 19, 1999 (64 FR 38706). The strategy presents a framework for

addressing air toxics in urban areas as required by section 112(k) of the CAA. The goals of the strategy

are to reduce by 75 percent the risk of cancer and substantially reduce non-cancer risks associated with

air toxics while ensuring that disproportionate risks are addressed. Specifically, the strategy does the

following:

• Outlines EPA’s approach for assessing health risks. The EPA will evaluate risks considering the

multiple sources of air toxics in our cities, whether they come from major industrial sources,

smaller sources (like drycleaners or gas stations), or cars and trucks. This includes risks from

consuming fish from waters contaminated by urban air toxic deposition.
Chapter III

Major Programs and Activities

Page III-16 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

• Builds on the substantial emission reductions already achieved from cars, trucks, fuels, and

industries such as chemical plants and oil refineries. The strategy outlines actions to reduce

emissions of air toxics and to improve EPA’s understanding of the health risks posed by air

toxics in urban areas.

• Identifies a list of the 33 air toxics that pose the greatest threat to public health in urban areas,

considering multipathway exposure, such as fish consumption, in the identification process.

These 33 air toxics are a subset of the 188 air toxics and include the Great Waters pollutants of

concern mercury, cadmium, lead, dioxins and furans, POM, PCBs, and HCB.

• Identifies the 30 of these 33 urban air toxics with the greatest contribution from smaller

commercial and industrial operations or so-called “area” sources. The CAA requires EPA to

ensure that 90 percent of the aggregate emissions of each of the 30 identified HAPs are subject to

regulation through EPA’s established air toxics program. In order to address this requirement,

EPA identified 29 area source categories that are significant contributors to the emissions,

including sources of mercury, cadmium, lead, POM, dioxins and furans. Currently, EPA has

regulations under development or completed for 16 of these area source categories and intends to

develop regulations for the remaining 13 area source categories over the next 5 years. The EPA

intends to list additional area sources by 2003 as better inventory data become available. 

The strategy also addresses the Agency’s efforts to date to assess the public health risk from air

toxics from mobile sources and highlights EPA’s expectation for additional regulations targeting toxics

emissions from motor vehicles and fuels. In the strategy, EPA describes plans to consider diesel

emissions in the upcoming mobile source air toxics regulation and to issue a rule (the proposed “Tier II

rule”; see page III-29) which will reduce levels of diesel emissions significantly in both urban and rural

areas. 

Rules for Solid Waste Combustion, Including Large Municipal

Waste Combustors and Hospital/Medical/Infectious Waste

Incinerators (CAA Section 129)

 Section 129 of the CAA directs EPA to control solid waste combustion and set emission limits

for dioxins and furans, cadmium, lead, mercury, and NOx (all pollutants of concern to the Great Waters), 

as well as particulate matter, opacity, sulfur dioxide, carbon monoxide, and hydrogen chloride. For

existing solid waste combustion units, section 129 requires EPA to develop emission guidelines. These

guidelines do not directly regulate the units. Rather, they establish requirements for State plans, which

are the vehicle by which States implement the guidelines. For new units, section 129 requires EPA to

develop technology-based performance standards following section 111 of the CAA. Section 129

further subjects solid waste combustion units to the section 112(f) residual risk program, which was

discussed earlier in this section. 

Final rules are now in place for large municipal waste combustors (MWC) and for

hospital/medical/infectious waste incinerators (HMIWI, or often called medical waste incinerators). 

There are also rules under development for small municipal waste combustors, commercial/industrial

waste incineration, and other solid waste incineration. The commercial/industrial waste incineration rule

is planned to be finalized by November 15, 2000; the small municipal waste combustor rule is planned to

be finalized by 2001.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-17

Large MWC are those units with a capacity of at least 250 tons of waste per day. The EPA

initially promulgated standards for new units and guidelines for existing units on December 19, 1995 and

revised them on August 25, 1997. The 24 States with large MWCs were required to submit emission

guidelines implementation plans to EPA by December 19, 1997. The State plans include source and

emission inventories, testing and monitoring, as well as generic or site-specific compliance schedules. 

The MWC Federal Plan adopted in November 1998 applies to large MWCs until State plans are

approved. The Federal Plan ensures that large MWCs are on track to complete pollution control

equipment retrofit schedules to meet the final compliance date of December 19, 2000. The emission

guidelines affect 70 large MWCs and will reduce toxic air pollutant emissions by 112,000 tons per year.

Table III-2 provides the nationwide emission estimates and expected percent reductions for pollutants of

concern to the Great Waters. The control equipment expected to be used at a typical existing plant

reduce dioxin emissions by 99 percent, mercury emissions by over 90 percent, NOx emissions by 40

percent, and will sharply reduce other air pollutants like lead and cadmium, as shown in Table III-3. 

Table III-3 

Emission Reductions Expected from Control Equipment Used 

to Retrofit A Typical Existing MWC Plant

Pollutant Typical

Uncontrolled Level

Typical

Controlled Level Percent Reduction

Dioxin/furan (ng/dscm) total mass 1,000 3 99+ 

Particulate matter (mg/dscm) 3,700 4 99+ 

Cadmium (mg/dscm) 1.2 0.001 99+ 

Lead (mg/dscm) 25 0.01 99+ 

Mercury (mg/dscm) 0.65 0.02 90+ 

Sulfur dioxide (ppmv) 160 5 90+ 

Hydrochloric acid (ppmv) 500 10 95+ 

NOx (ppmv) 225 130 40+ 

 Source: U.S. EPA 1998h

For HMIWI, the emission guidelines and performance standards were published in the Federal

Register in September 1997. The guidelines will apply to about 2,400 existing HMIWI; full compliance

with them is no later than September 2002. In addition, EPA developed a new source performance

standard (NSPS) that applies to new HMIWI that commence construction after June 20, 1996 or that

commence modification after the effective date of the NSPS (i.e., 6 months after promulgation). In the

first 5 years after promulgation, the NSPS are expected to apply to about 10 to 70 new HMIWI. The

pollutants addressed, regulatory baseline emissions, and expected reductions of the emission guidelines

and the NSPS are presented in Tables III-4 and III-5, respectively.

STATIONARY SOURCE CONTROLS ADDRESSING NOx

The CAA provisions specifically addressing NOx have had the greatest effect on controlling

stationary source nitrogen compound emissions. Primarily because of these provisions, nationwide NOx

emissions are projected to decrease gradually for the next few years, ultimately leveling off at around 19

million metric tons per year around 2005, representing a decrease from the 1996 level of around 21.2

million metric tons/year (U.S. EPA 1998l). Nitrogen oxide emissions are projected to remain at about
Chapter III

Major Programs and Activities

Page III-18 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

that level through 2010. Figure III-1 indicates projected trends in NOx emissions through 2010. The

EPA plans to update these projections in 2000 using newer models for mobile and stationary sources. 

Among other benefits, these reductions will reduce rates of atmospheric nitrogen deposition affecting the

Great Waters.

This section summarizes recent developments in key CAA programs that have recently or will in

the near future reduce NOx emissions from stationary sources. It lists and briefly describes, in Table III6, CAA regulatory controls that will result in NOx

 emission reductions. It also presents the sources

affected, compliance dates, and the emission reductions that each regulation is expected to achieve. 

Finally, the section discusses the effect on NOx emissions of possible new 8-hour ozone and PM2.5

standards, as well as the regional haze rule.

Table III-4

Emission Reductions Expected from Existing HMIWI

 

Pollutant Baseline

Emissions

Nationwide Emission

Reduction

Nationwide Emission

Reduction (percent)

a

Particulate matter (Mg/yr) 940 820-870 88-92

Carbon monoxide (Mg/yr) 460 340-380 75-82

Total Dioxin/Furanb (g/yr) 7,200 6,900-7,000 96-97

Dioxin/Furan TEQb (g/yr) 148 141-143 95- 97

Hydrochloric acid (Mg/yr) 5,700 5,600 98

Sulfur dioxide (Mg/yr) 250 0-74 0-30

NOx (Mg/yr) 1,200 0-350 0-30

Lead (Mg/yr) 11 8.6-9.4 80-87

Cadmium (Mg/yr) 1.2 0.91-1.0 75-84

Mercury (Mg/yr) 14.5 13.5-13.8 93-95

a These reductions represent reductions from the regulatory baseline. Percent reductions have been calculated

based on the actual (unrounded) values for baseline emissions and nationwide emissions reduction.

b Total dioxin/furan reflects total tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans, as measured

by EPA Reference Method 23. TEQ reflects the toxic equivalent quantity of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin

using international toxic equivalency factors.

Source: U.S. EPA 1998g
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-19

Table III-5

Emission Reductions Expected at New HMIWI after 5 Years of NSPS Implementation

Pollutant Baseline Emissions Nationwide Emission

Reduction

Nationwide Emission

Reduction (percent)a

Particulate matter (Mg/yr) 28 23-25 85-92

Carbon monoxide (Mg/yr) 14 0-7.0 0-52

Total Dioxin/Furanb (g/yr) 47 35-41 75-87

Dioxin/Furan TEQb (g/yr) 1.1 0.80-0.93 74-87

Hydrochloric acid (Mg/yr) 64 61-62 95-98

Sulfur dioxide (Mg/yr) 28 0-15 0-52

NOx (Mg/yr) 130 0-69 0-52

Lead (Mg/yr) 0.39 0.33-0.36 85-92

Cadmium (Mg/yr) 0.051 0.042-0.046 83-91

Mercury (Mg/yr) 0.21 0.10-0.16 45-74

a

 These reductions represent reductions from the regulatory baseline. Percent reductions have been calculated

based on the actual (unrounded) values for baseline emissions and nationwide emissions reduction.

b Total dioxin/furan reflects total tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans, as measured

by EPA Reference Method 23. TEQ reflects the toxic equivalent quantity of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin

using international toxic equivalency factors.

Source: U.S. EPA 1998j

Figure III-1

Projected National NOx Emission Trends, 1996-2010

(U.S. EPA 1998l)
Chapter III

Major Programs and Activities

1

 Although the NOx

 RACT compliance date was over 4 years ago and the NOx RACT was covered in the Second Great Waters Report to Congress, it is included

here again for reference because it relates to some of the more recent regulations listed in this table.

Page III-20 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table III-6

Recent Regulations Affecting Stationary Source NOx Emissions

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

NOx RACT1 May 31, 1995 Boilers and combustion units (varies

from State-to-State) 

Varies from State-to -

State 

Estimated 30 to 50

percent reduction from

applicable sources. 

[some overlap with Title

IV Acid Rain

reductions]

Title IV Acid Rain NOx Group 1 (Phase I): January 1,

1996

Group 1 (Phase II) and Group 2:

January 1, 2000

Group 1: Coal-fired dry bottom wallfired boilers, tangentially fired boilers;

Group 2: wet bottom boilers,

cyclones, cell burner boilers, and

vertically-fired boilers (nationwide).

Group 1– Phase I:

Dry-bottom wall-fired

boilers: 0.50 lb/mmBtu

Tangentially-fired

boilers: 0.45 lb/mmBtu

Group 1 -- Phase II:

Dry-bottom wall-fired

boilers: 0.46 lb/mmBtu

Tangentially-fired

boilers: 0.40 lb/mmBtu

Group 2:

Wet-bottom boilers: 

0.84 lb/mmBtu

Cyclones: 0.86

lb/mmBtu

Cell burner boilers: 

0.68 lb/mmBtu

Vertically-fired boilers: 

0.80 lb/mmBtu

2.06 million metric 

tons/yr

(2000)

[some overlap with NOx

RACT reductions]
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

2

 Based on the difference between 1990 levels (490,000 tons) and NOx budget for 2003 (143,000 tons). 

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-21

Ozone Transport

Commission

Memorandum of

Understanding

Phase I (NOx RACT--see

above): May 31, 1995

Phase II: May 1, 1999

Phase III: May 1, 2003

Fossil fuel-fired boilers and indirect

heat exchangers with a maximum

rated heat input capacity of 250

mmBtu/hour or more (applies to

northeast Ozone Transport Region,

including Washington, DC and the

11 northeastern States)

Phase I: 

Varies from State-toState (see NOx

 RACT

above)

Phase II: 

Less stringent of 65

percent reduction for

Inner Zone and 55

percent reduction for

Outer Zone from

baseline levels or 0.20

lb/mmBtu

Phase III:

Less stringent of 75

percent reduction

(Inner Zone and Outer

Zone) - from baseline

levels or 0.15

lb/mmBtu

Northern zone - Less

stringent of 55 percent

reduction from baseline

levels or 0.20 lb/mmBtu

0.32 million metric 

tons/yr

(2003)2
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

3

 The EPA also proposed the Federal implementation plan in September 1998 in the event that any of the 22 States or the District of Columbia do not submit

revised SIPs to meet the NOx SIP call. At the same time, EPA proposed actions on petitions filed under section 126 of the CAA by eight northeastern States. 

The petitions requested that EPA make a finding that NOx emissions from certain stationary sources contribute to ozone non-attainment problems in the

petitioning States. The final action on the section 126 petitions was completed on April 30, 1999, but revised in December 1999 in light of rulings by the DC

Circuit Court of Appeals related to the NOx SIP call and the 8 hour ozone standard. 

4

 The most likely sources to be affected include electric generation units (EGUs) including units of 25 MW or less; non-EGUs, boilers, and turbines; stationary

internal combustion engines; and, cement manufacturing plants. As a result of action by the DC Circuit Court of Appeals in March 2000, WI and portions of

GA and MO were removed from the areas subjected to the SIP call. 

5

 Emission reductions are for the ozone season (May 1 to September 30). Includes original estimate of NOX reductions from EGUs, non-EGUs, mobile, and area

sources from areas subjected to the SIP call. This number will be slightly less with the removal of WI and portions of GA and MO. 

Page III-22 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

NOx SIP Call3 State NOx Budget Programs

(and NOx reductions) must be

implemented by May 1, 2003;

budgets to be achieved by 2007

22 States and the District of

Columbia (DC) 4

The States and DC are

directed to develop

regulations to meet NOX

budgets as defined by

EPA and reduce NOX

and ozone transport. 

The EPA will implement

these requirements

under a Federal

implementation plan if

the States and DC do

not.

1.05 million metric tons

per ozone season

(2007)5
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

6

 For which construction, modification, or reconstruction commenced after July 9, 1997. 

7

 This limit was changed from an input-based format (where emissions are linked to the fuel used) to an output-based format (where emissions are linked to the

amount of energy generated). 

8

 This emission limit was revised to be equivalent to the new unit output-based limit.

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-23

NSPS for New Fossil

Fuel-Fired Steam

Generating Units

(NSPS Subpart Da

and Db)

November 16, 1998 (effective

date)

New6 electric utility, industrial,

commercial, and institutional steam

generating units

New utility boilers: 1.6

lbs/megawatt hour of

energy output (gross

output)7

Modified or

reconstructed existing

utility boilers: 0.15

lbs/million Btu emission

limit8

New and existing

industrial boilers: 0.20

lbs/million Btu

0.04 million metric 

tons/yr

(2002)

Section 126 Petition

Rule

May 1, 2003 Utilities (capacity of 25 megawatts or

greater) and industrial boilers and

combustion turbines (capacity of 250

million Btu/hour or greater) in 12

eastern States and the District of

Columbia (NY, NJ, PA, DE, MD, DC,

VA, WV, NC, KY, IN, OH, MI)

Utilities: 0.15 NOx/

million Btu

Boilers/turbines: 60

percent reduction in

NOx from controlled

levels

510,000 tons of NOx

per ozone season

(2007)
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

9

 Constructed on or before September 20, 1994. 

Page III-24 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Emission Guidelines

for Municipal Waste

Combustors

No later than December 19,

2000

Existing MWC9 with combustion

capacity > 250 tons/day of MSW per

unit not specifically covered by an

approved State plan

NOx emission limits for

affected facilities:

Mass burn waterwall

–205 ppmv

Mass burn rotary

waterwall – 250 ppmv

Refuse-derived fuel

combustor – 250 ppmv

Fluidized bed

combustor – 240 ppmv

Mass burn refractory --

no limit

0.02 million metric

tons/yr

(2000)

Emission Guidelines

for Existing

Hospital/Medical/

Infectious Waste

Incinerators (HMIWI)

and NSPS for new

HMIWI

Existing sources: no later than

September 15, 1997 (effective

date)

New sources: March 15, 1998 or

6 months after start-up (effective

date)

New HMIWI that commenced

construction after June 20, 1996,

existing HMIWI (built on or before

June 20, 1996), and existing units

that commence modification after

March 15, 1998

NOx emission

concentrations for new

and existing facilities: 

250 ppmdv

New HMIWI: 0 to 69

metric tons/yr or 0 to 52

percent per year

reduction. 

Existing HMIWI: 0 to

390 metric tons/yr or 0

to 30 percent per year

reduction

Mobile Source

Regulations

Tier I Tailpipe standards: 1996 Tier I Tailpipe standards: light duty

vehicles and trucks

Tier I Tailpipe

standards 

Tier I Tailpipe

standards: 850,000

metric tons of NOx per

year (2010)
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-25

Tier II Gasoline Sulfur Program: 

2004 for gasoline sulfur content

nationwide; 2004-2009 for

tighter NOx standards for

vehicles

Gasoline nationwide, and cars, light

trucks, and SUVs up to 10,000

pounds gross weight sold outside

California

Establishes NOx

standard of 0.07 gram

per mile for all

passenger vehicles ,

including light duty

trucks, up to 10,000

pounds, phased in over

several model years

with interim standards

more stringent than

currently for light

trucks, which are

allowed the longest

time to meet the 0.07

gram per mile standard. 

Averaging is allowed

using a bin-based

approach. These

standards are

comparable to

California’s LEV-2

program.

4.049 million metric

tons of NOx per year

(2030)

National Low Emission Vehicle

(NLEV) Standards: 1999 in NE

ozone transport region; 2001

nationwide

National Low Emission Vehicle

(NLEV) Standards: light-duty

vehicles and light light-duty trucks

NLEV Standards:

Establishes the

adoption of the

California Low

Emission Vehicle (CAL

LEV) program

throughout the

Northeast Ozone

Transport Region for

the 1999 and 2000

model years, and

across the entire Nation

starting with the 20001

model year

NLEV Standards:

181,000 metric tons of

NOx per year (2007)
Chapter III

Major Programs and Activities

Regulation Compliance Date Affected Sources NOx

 or Related

Requirement

Projected NOx

Emission Reductions

(year by which

reductions will be

achieved)

Page III-26 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Heavy-duty highway diesel

standards: 2004

Heavy-duty highway diesel

standards: heavy-duty highway

diesel engines

Heavy-duty highway

diesel standards: 2.4

g/bhp-hr for

NMHC+NOx or,

2.5 g/bhp-hr for

NMHC+NOx with a limit

of 0.5 g/bhp-hr on

NMHC

Heavy-duty highway

diesel standards: 1

million metric tons of

NOx per year (2020)

Heavy-duty non-road diesel

standards: 1999 - 2006

Heavy-duty non-road diesel

standards: heavy-duty diesel

construction, agricultural, industrial

engines

Heavy-duty non-road

diesel standards: 9.2

g/kW-hr (different start

years depending on

size of vehicle)

Heavy-duty non-road

diesel standards: 1.1

million metric tons of

NOx per year (2010)

Small spark-ignition engine

standards, phase I: 1997

Small spark-ignition, nonhandheld engine standards,

phase II: 2001-2007

Small spark-ignition engine

standards, small spark-fired engines

Small spark-ignition, non-handheld

engine standards

Small spark-ignition

engine standards: (See

40 CFR 90.103)

Small spark-ignition,

non-handheld engine

standards

Phase I and II: 9,000

metric tons of NOx per

year (2020)

Locomotive engine standards:

2000

Locomotive engine standards: new

and rebuilt locomotive engines

Locomotive engine

standards: (See 63 FR

18982, April 16, 1998)

Locomotive engine

standards: 449,000

metric tons of NOx per

year (2010)
Chapter III

Major Programs and Activities

10 The affected dry-bottom wall-fired boilers must meet a limitation of 0.50 lbs of NOx

 per mmBtu averaged over

the year, and tangentially-fired boilers must achieve a limitation of 0.45 lbs of NOx

 per mmBtu averaged over the

year.

11 The limits are 0.68 lb/mmBtu for cell burners, 0.86 lb/mmBtu for cyclones greater than 155 MWe, 0.84 lb/mmBtu

for wet-bottom boilers greater than 65 MWe, and 0.80 lb/mmBtu for vertically-fired boilers. 

Deposition of Air Pollution to the Great Waters – 3rd Report to Congress 2000 Page III-27

Acid Rain Program NOx Reduction

Title IV of the CAA requires reductions in NOx emissions from the electric power generating

industry. The acid rain NOx requirements incorporate a two-phased strategy to reduce NOx emissions

from boilers. In the first phase, which became effective January 1, 1996, certain Group 1 boilers (i.e.,

dry-bottom wall-fired boilers and tangentially-fired boilers) were required to comply with specific NOx

emissions limitations.10 All additional Group 1 boilers must comply in the second phase, which became 

effective on January 1, 2000. Also included in the second phase are NOx emissions limits for all Group 2

boilers (i.e., wet-bottom wall-fired boilers, cyclones, boilers using cell-burner technology, and verticallyfired boilers).11

In April 1995, EPA promulgated the rule establishing NOx emission limits for Group 1 boilers. 

These regulations also allowed Phase II Group 1 units to use an “Early Election” Compliance Option. 

Under this regulatory provision, Phase II Group 1 NOx affected units can demonstrate compliance with

the higher Phase I limits for their boiler type from 1997 through 2007 and not meet the more stringent

Phase II limits until 2008. If the utility fails to meet this annual limit for the boiler during any year, the

unit is subject to the more stringent Phase II limit for Group 1 boilers beginning in 2000 or the year

following the exceedance, whichever is later. As a result of these rules, NOx reductions were projected

to be approximately 400,000 tons per year in 1996 through 1999 (Phase I) and 2,060,000 metric tons per

year in 2000 and subsequent years (Phase II). 

NOx SIP Call, Section 126 Petitions, and Federal Implementation

Plans

Many States have found it difficult to attain the ozone national ambient air quality standard

(NAAQS) because of widespread regional transport (i.e., from sources in other States) of ozone and its

precursors, NOx and volatile organic compounds (VOCs). In 1995, the Ozone Transport Assessment

Group (OTAG) was formed to address the regional transport problem in the eastern half of the U.S. (i.e.,

the 37 easternmost States). The OTAG process was a collaborative effort among 37 affected States, the

District of Columbia, EPA, and interested members of the public, including environmental groups and

industry representatives. The OTAG concluded that further regional reductions in NOx emissions are

needed to reduce the transport of ozone and its precursors. Furthermore, OTAG recommended in July

1997 that major sources of NOx emissions (i.e., utility and other stationary sources) be controlled under

State NOx budgets and that an emissions trading program be developed. 

In response to the OTAG recommendations, EPA issued the NOx State implementation plan

(SIP) call on October 27, 1998 (63 FR 57356). The SIP call limits summer season NOx emissions for 22

States and the District of Columbia that are significant contributors to ozone in downwind areas. The

EPA directed the 23 jurisdictions to amend their SIPs to ensure that the NOx budgets are met. The EPA

set these budgets by assessing the reductions that could be obtained through cost-effective controls on

electricity generating units and large industrial boilers. However, in order to meet the SIP requirements,
Chapter III

Major Programs and Activities

12 Few sources emit ozone; rather it is formed in the atmosphere through the reaction of VOCs and NOx

. To attain

the ozone standard, States typically require VOC and NOx controls.

Page III-28 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

States can adopt NOx trading programs. These programs will be similar to the successful SO2 trading

program under EPA’s Acid Rain program. The NOx SIP call is expected to reduce atmospheric nitrogen

emissions by up to 1.05 million tons per ozone season, which should reduce loadings into the Great

Waters in the eastern U.S. [NOTE: In March 2000, in response to arguments made before the court, the

Circuit Court of Appeals for the District of Columbia removed Wisconsin and portions of Georgia and

Missouri from the list of States subject to the call. The emission reduction estimate will be slightly less

with these removals.] 

At the same time that EPA promulgated the NOx SIP call rule, EPA also proposed that NOx

Federal implementation plans (FIPs) may be needed if any State fails to respond to the final NOx SIP call. 

In addition, a number of northeastern States petitioned EPA, as allowed by section 126 of the CAA, to

address air pollution transported from upwind States and requested that EPA make a finding that NOx

emissions from certain major stationary sources significantly contribute to ozone nonattainment

problems. Such a finding would require EPA to establish Federal emissions limits for these sources. On

April 30, 1999, EPA took final action on the petitions and identified upwind sources that significantly

contribute to ozone nonattainment problems. In December 1999, EPA revised the April 126 petition rule

in light of the rulings by the DC Circuit Court of Appeals related to the NOx SIP call and the 8 hour

ozone standard. The FIPs and the section 126 petition action would directly impose regulatory

requirements on these emissions sources, including a capped, market-based trading program for certain

stationary sources. 

New Source Performance Standards

New source performance standards (NSPS) require emission reductions in both attainment and

nonattainment areas. Section 111 of the CAA requires EPA to identify “source categories” emitting

criteria air pollutants (e.g., ozone) or precursors of criteria pollutants (e.g., NOx and VOCs) and to

establish emissions limits for new, modified, and reconstructed sources of emissions.12 Emissions limits

must be based on the “best demonstrated technology,” and must apply to all new sources in the country

after the effective date of the rule. To date, EPA has promulgated approximately 100 NSPS, of which

approximately ten directly control NOx emissions.

In September 1998, under court order, EPA finalized an NSPS for fossil fuel-fired utility and

industrial boilers. Specifically, the final standards revised the NOx emission limits for electric utility, 

industrial, commercial, and institutional steam generating units for which construction, modification, or

reconstruction commenced after July 9,1997. These final revised NOx emission limits will reduce the

projected growth in NOx emissions from new sources by approximately 42 percent (41,500 metric

tons/year) from levels allowed under current standards.

New Source Review and RACT

Under the CAA, States must apply similar requirements to major stationary sources of NOx

emissions as are applied to major stationary sources of VOCs because these two pollutants are precursors

to ozone. These new NOx provisions require (1) existing major stationary sources to apply reasonably

available control technology (RACT) in certain ozone nonattainment areas and ozone transport regions,

(2) new or modified major stationary sources to offset increased emissions and to install controls

representing the lowest achievable emission rate (LAER) in areas that do not attain the ozone NAAQS
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-29

(i.e., ozone nonattainment areas) and ozone transport regions, and (3) new or modified major stationary

sources to install the best available control technology (BACT) in ozone and NO2 attainment areas. 

MOBILE SOURCE PROGRAM ACTIVITIES

Collectively, mobile sources are major contributors of nitrogen compounds to the atmosphere. 

The EPA’s Office of Mobile Sources (OMS) is responsible for regulatory oversight of air pollution

emitted from mobile sources, primarily automobiles, but also including marine, aircraft, locomotive, and

small engines such as lawn and garden equipment. The regulatory strategies often focus on both vehicle

emissions and fuel composition. 

Historically, OMS has led the effort to eliminate lead from gasoline and require more stringent

tailpipe emissions and fuel changes that benefit air quality. Recent accomplishments by OMS that affect

Great Waters pollutants of concern are focused primarily on nitrogen compounds. These include the

following.

C Between 1994 and 1996, OMS phased in Tier I tailpipe emission standards affecting light-duty

vehicles and trucks. The EPA expects the standards to reduce NOx emissions by 850,000 metric

tons per year by 2010. The Tier II tailpipe emission standards, which will further limit

emissions, were proposed on May 13, 1999 and, if finalized, will reduce NOx emissions by an

additional 2.8 million tons by 2030 (see below and the Federal Register at 64 FR 26004, May 13,

1999).

C The national low emission vehicle, or NLEV, standard begins with model year 1999 vehicles in

the Northeast Ozone Transport Region and throughout the Nation in 2001. Compliant vehicles

will meet California emission standards and will reduce NOx emissions by 181,000 metric tons

per year by 2007.

C Recent regulations for heavy-duty highway diesel engines will result in one million metric tons

per year reductions in NOx emissions by 2020. Heavy-duty non-road diesel standards covering

construction, agricultural, and industrial engines will be phased in between model years 1999 and

2006 and will result in reductions of 1.1 million metric tons per year of NOx by 2010.

C New regulations covering small spark-ignition engines will reduce NOx emissions by 9,000

metric tons per year in 2020.

C New requirements for locomotive engines, both new and rebuilt, will come into effect in 2000

and result in NOx reductions of 449,000 metric tons per year by 2010.

Tier II Emission Standards for Vehicles and Gasoline Sulfur

Standards for Refineries

In December, 1999 (65 FR 6698), EPA issued new, more protective standards for tailpipe

emissions from all passenger vehicles (including sport utility vehicles (SUVs), minivans, and pick-up

trucks) and new standards to reduce sulfur levels in gasoline to ensure the effectiveness of low emissioncontrol technologies in vehicles. These new standards were in response to EPA’s July 1998 Tier II

Report to Congress which concluded that more stringent vehicle standards are needed to meet the ozone

and particulate matter air quality standards, and that technology would be available to meet such

standards cost-effectively. The EPA designed the new standards in close consultation with the auto and
Chapter III

Major Programs and Activities

Page III-30 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

oil industries, emissions control manufacturers, the States, and public health, consumer, and

environmental groups (U.S. EPA 1999c).

Under the Tier II standards, SUVs, minivans, and pickup trucks are required to meet the same

protective standards as passenger cars, regardless of the type of fuel used. The standards also reduce the

amount of sulfur in gasoline, which will ensure the effectiveness of low emission-control technologies in

vehicles and reduce harmful air pollution. When fully implemented in 2030, the new tailpipe and

gasoline standards are expected to reduce NOx emissions from vehicles by 2.8 million tons, emissions of

particulate matter (i.e., soot) by 35,000 tons, and SO2 emissions from vehicles by 334,000 tons. The

significant environmental benefits of this program are expected to come at an average cost increase of

less than $100 per car and less than $200 per light-duty truck. Consumers would pay less than 2 cents

per gallon more for gasoline, or about $100 more over the life of an average vehicle (U.S. EPA 1999c). 

Additional information is available at http://www.epa.gov/otaq/tr2home.htm. 

OZONE AND PM NAAQS AND THE REGIONAL HAZE RULE

Since the Second Great Waters Report to Congress, EPA made revisions to the particulate matter

(PM) and ozone NAAQS. In addition, in April 1999, EPA issued the final regional haze rule to address

visibility impairment in national parks and wilderness areas (also known as Class I areas) caused by

numerous sources located over broad regions. Some of these Class I areas are associated with Great

Waters waterbodies, such as Isle Royal National Park in Lake Superior and Swan Quarter National

Wildlife Refuge in the Albemarle-Pamlico Estuary. Implementation of the NAAQS in conjunction with

the regional haze program is anticipated to improve visibility across the country as well as reduce NOx

emissions and consequently nitrogen deposition to coastal waters, particularly in the eastern U.S. The

EPA will have a better understanding of the NOx emission reductions resulting from these programs

when emissions and monitoring data are collected from the States, nonattainment areas are designated,

and the States submit implementation plans (U.S. EPA 1998f). 

However, on May 14, 1999, in response to a suit by the American Trucking Associations, Inc., a

panel of the Circuit Court of Appeals for the District of Columbia issued a decision vacating the revised

PM10 standard and stopping implementation of the new ozone standard. The U.S. Department of Justice

has appealed this decision. The court did not, however, prevent EPA from designating nonattainment

areas for the new ozone standard, and therefore EPA is considering doing so in 2000. For the new PM2.5

standards, which the court ruled should stay in place, EPA currently plans to designate attainment and

nonattainment areas as soon as air quality data are collected and analyzed, which is anticipated to be in

2004 or 2005.

OTHER NATIONAL PROGRAMS

Fish Contamination Program

The EPA’s Fish Contamination Program (FCP) provides technical assistance to States, tribes,

and others on matters related to persistent bioaccumulative toxics in fish and wildlife and associated

potential health risks to consumers. Since 1992, the FCP has worked with State and tribal agencies to

establish nationally-consistent methods and protocols for assessing contaminants in fish and wildlife for

the purpose of developing and managing consumption advisories. Additional activities of the FCP

include publishing guidance documents, maintaining national databases (e.g., of fish consumption

advisories), sponsoring conferences and training workshops, providing grants for advisory development
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-31

and special studies, developing outreach materials, and assisting States and tribes in the issuance of

consumption advisories. 

Since 1993, the FCP has published an annual report on trends in the number of fish and wildlife

consumption advisories. The National Listing of Fish and Wildlife Advisories (NLFWA) identifies all

State-, tribal-, and Federally-issued fish consumption advisories in the U.S. Recently, it has been

expanded to include Canadian provinces and territories. According to the 1998 NLFWA, the number of

consumption advisories in the U.S. rose by 125 in 1997 to a total of 2,299, a 5 percent increase from

1996. The number of waterbodies under advisory in 1997 represented 16.5 percent of the Nation’s total

lake acres and 8.2 percent of the Nation’s total river miles. The total number of advisories in the U.S.

increased for three major pollutants – mercury, dioxin, and DDT. The increase in advisories issued by

the States generally reflects an increase in the number of assessments of the levels of chemical

contaminants in fish and wildlife tissues, rather than an increase in contaminant levels (U.S. EPA

1998m).

Environmental Justice Initiatives

 Research indicates that people of different racial and ethnic backgrounds and income levels often

do not eat the same kinds and amounts of food (U.S. EPA 1995). For example, Native Americans and

the urban poor are at a greater risk for adverse health effects due to high rates of consumption of

potentially contaminated fish. Fetuses and young children are at risk because they are more vulnerable to

the effects of the pollutants of concern. Thus, these subpopulations may be disproportionately affected

by deposition of air pollutants to the Great Waters.

The EPA recognizes the relationship between health risks, environmental pollutants, and diet as a

potential environmental justice issue. Since 1992, EPA’s Office of Environmental Justice has served as

the point of contact for environmental justice outreach and educational activities, has provided technical

and financial assistance, and has disseminated environmental justice information. In conjunction with

regional and headquarters offices, this office has initiated many programs to address the environmental

concerns among minority, low-income, and Native American and Alaska Native communities (U.S. EPA

1995). Likewise, EPA created the American Indian Environmental Office in 1994 for the purpose of

coordinating the EPA-wide effort to strengthen public health and environmental protection on Native

American lands (U.S. EPA 1998u). An example of EPA’s efforts is the passage of a resolution by the

National Environmental Justice Advisory Council of EPA’s Office of Environmental Justice in

December 1998 that was developed by the Indigenous People Subcommittee pertaining to the effects of

mercury contamination on American Indian populations. This resolution requires EPA’s Office of

Pollution Prevention and Toxic Substances to share the 1998 Mercury Action Plan with tribes, to provide

educational and health information to tribes, to adopt a Mercury Action Plan and regulatory authority to

eliminate anthropogenic mercury emissions by 2010, to establish baseline emission standards, and to

adopt enhanced reporting requirements for mercury emission sources.

Recent studies continue to examine the relationship between increased health risks in certain

subpopulations and the consumption of fish from the Great Lakes. Study results show that some

subpopulations are not as aware of fish advisories as other populations, and that human health effects

from consumption of fish from contaminated areas vary. Chapter II describes additional relevant

research relating to exposure and effects of Great Waters Pollutants of concern and sensitive or highlyexposed subpopulations.
Chapter III

Major Programs and Activities

Page III-32 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Children Experience Increased Risk From

Environmental Hazards Because:

Their systems are still developing making them

more susceptible to environmental threats.

They eat more food, drink more fluids, and

breathe more air per pound of body weight

making them more exposed to environmental

hazards.

Their behavior, such as crawling on the

ground, and lack of ability to protect themselves

exposes them to hazards that adults can easily

avoid.

Children’s Health Initiatives

Children face environmental health threats from many of the Great Waters pollutants of concern. 

In addition, child exposures to pollutants tend to occur through multiple exposure routes, including

inhalation, ingestion, dermal contact, and prenatal (transplacental) exposure. For example:

C Prenatal and childhood exposure to

contaminants, such as lead, PCBs, and

mercury, via multiple exposure pathways may

inhibit a child’s intellectual development and

ultimately may result in behavioral problems. 

C Exposure to endocrine disrupting chemicals,

such as organochlorine pesticides and PCBs,

may cause birth defects and alterations of

normal childhood growth and development 

(Browner 1998, U.S. EPA 1998w).

In an effort to protect children from

environmental health threats, EPA published its

National Agenda to Protect Children’s Health from Environmental Threats in April 1996. This agenda

calls for the consideration of children’s risks in all appropriate agency actions and a greater emphasis on

research to support children’s risk assessment activities (U.S. EPA 1996a). In addition, EPA established

its Office of Children’s Health Protection (OCHP) in May 1997 to ensure the implementation of the

President’s 1997 Executive Order to Protect Children from Environmental Health and Safety Threats. 

The OCHP’s mission is to make the protection of children’s health a fundamental goal of public health

and environmental protection in the U.S. The office supports and facilitates EPA efforts to protect

children from environmental threats (U.S. EPA 1998t).

The President’s Executive Order requires all Federal agencies to address health and safety risks

to children, coordinate research priorities on children’s health, and ensure that their standards take into

account special risks to children. The EPA documents its current actions in regard to children’s health in

The EPA Children’s Environmental Health Yearbook (U.S. EPA 1998q). The yearbook includes sections

on asthma and respiratory effects, childhood cancer, developmental and neurological toxicity, health

effects of pesticides, and potential risks from contaminated surface and ground water. To coordinate

research efforts, EPA and the National Institute of Environmental Health Services developed a grant

program to support the establishment of Centers for Children’s Environmental Health and Disease

Prevention Research. The purpose of these centers is to foster the advancement of children’s health

through enhancing the public’s understanding of basic disease mechanisms and promoting communitybased prevention activities related to children’s respiratory disorders, childhood learning, and growth and

development (U.S. EPA 1998t).

 The EPA, in coordination with other Federal agencies, has begun several efforts to address these

specific threats. Most notably, EPA has conducted an Agencywide Risk Assessment Forum colloquium

on children’s risk and has begun to review and revise several of its risk assessment guidance documents

to identify areas where children’s health protection is or should be considered. Mercury, lead, dioxin,

HCB, and PAHs are among the chemicals included in this risk characterization (Browner 1998). As part

of this effort, EPA requested that the Federal Children’s Health Protection Advisory Committee

(CHPAC) recommend existing standards that may merit reevaluation in order to further protect

children’s environmental health. One recommendation was to reevaluate the chlor-alkali NESHAP
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-33

(mercury). In response, EPA has begun a process to revise this standard, including a risk assessment of

mercury emissions from chlor-alkali plants (64 FR 5277, February 3, 1999). Also, EPA, the Department

of Health and Human Services, and other Federal agencies have begun to develop a comprehensive crossgovernment strategic plan to address the causes of children’s asthma and the scope of the problem

(Browner 1998).
Chapter III

Major Programs and Activities

Page III-34 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 New York Sea Grant Extension, Pat MacNeill

III.B REGIONAL AND WATERBODY-SPECIFIC PROGRAMS

All of the Great Waters are affected by the policies and activities of multiple communities and

governments on their shores. The Great Lakes, for example, are affected by the environmental

management decisions of two nations, one Canadian Province, eight States, a number of tribes, and

countless municipalities. Intergovernmental or multistakeholder institutions (e.g., the Lake Michigan

Forum) have been established for many of the Great Waters to coordinate resource management decision

making and resolve conflicts. In addition, EPA and NOAA, as directed by Congress, administer several

programs to address particular regional and waterbody-specific environmental challenges. These

programs lead or support many efforts to evaluate or control the impacts of pollution, including pollution

via atmospheric deposition, on the Great Waters ecosystems. 

The EPA has found that regional environmental challenges, such as those facing the Great

Waters, are often best solved through collaboration with local stakeholders and with a holistic approach

that addresses human social and economic needs as they relate to environmental quality. The EPA has

used these approaches in a number of place-based (i.e., geographically-based) programs, including the

National Estuary Program; Great Lakes, Chesapeake Bay, and Clean Lakes Programs; and, the Regional

Geographic Initiative. These approaches are further developed in EPA’s Community-Based

Environmental Protection (CBEP) program. The EPA’s Strategic Plan (EPA 1997c) recognized CBEP as

the Agency’s main tenet for “reinventing” its approach to environmental protection by considering

environmental problems across organizational and political boundaries and in a multimedia fashion. The

Agency is now using the CBEP approach in several of the regional and waterbody-specific programs and

activities described in this section.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-35

IJC Identified Seven AOCs That Have

Developed Particularly Successful

Remediation Strategies

/ Black River (Ohio)

/ Grand Calmumet River/Indiana Harbor 

 Ship Canal

/ Hamilton Harbor (Ontario)

/ Ashtabula River (Ohio)

/ Bay of Quinte (Ontario)

/ Manistique River (Michigan)

/ Muskegon and White Lakes (Michigan)

GREAT LAKES PROGRAM

Administered by EPA’s Great Lakes National Program Office (GLNPO), the Great Lakes

Program consists of programs and activities initiated by EPA, States, tribes, and their partners that are

designed to address challenges facing the Great Lakes ecosystem. Several of these activities involve

atmospheric deposition and Great Waters pollutants of concern. 

The GLNPO has provided funds for monitoring of toxics in conjunction with the Episodic

Events/Great Lakes Experiment (EEGLE) Study research effort. The EEGLE Study is being funded by

the National Science Foundation and NOAA to study nutrient transport in a plume that occurs in Lake

Michigan annually. This effort enables the study of air-water exchange of toxics in this plume. This

information will be used in support of the Lake Michigan Mass Balance Study (LMMBS) by providing

insight into the air/water exchange of PCBs and PAHs. The project will also provide information

necessary to determine the spatial and temporal variation of loadings across large lakes. This project is a

pilot for future air/water toxics sampling projects, such as planned additional over-water measurements

for the Integrated Atmospheric Deposition Network (IADN) program.

In addition to these activities, the Great Lakes Program is continuing to utilize remedial action

plans (RAPs) for areas of concern (AOCs) and lakewide management plans (LaMPs) to target ecological

problems on a geographic basis, in accordance with the 1978 Great Lakes Water Quality Agreement

(GLWQA) between Canada and the U.S. The LaMPs and RAPs are tools for reducing the input of

pollutants to the Great Lakes and restoring the environmental quality of the Great Lakes basin.

The LaMPs and RAPs target ecological problems on a geographic basis and provide a

community-based approach to identifying and solving environmental problems. Both tools were

originated in response to the GLWQA goals of restoring and maintaining the chemical, physical, and

biological integrity of aquatic ecosystems. The RAPs were first established in 1985 to provide more

uniform guidance on how to restore uses in AOCs. Rivers, connecting channels, harbors, and

embayments of the Great Lakes are designated as AOCs if there is an impairment of beneficial use or the

area’s ability to support aquatic life. Unlike RAPs, the development and implementation of LaMPs for

each of the five Great Lakes was a specific objective of the GLWQA. The LaMPs are frequently

integrated with RAPs and other efforts that are best suited to address issues of local concern. 

The Great Lakes Water Quality Board of the

International Joint Commission (IJC) established 42

AOCs in the Great Lakes basin (Figure III-2): 26 within

the jurisdiction of the U.S., 12 within Canadian

jurisdiction, and 5 shared by both countries. The RAPs

are being developed for each of these AOCs to address

impairments to any one of the 14 beneficial uses (e.g.,

restrictions on fish and wildlife consumption, dredging

activities, or drinking water consumption) associated with

these areas. The RAPs are prepared and implemented by

the eight Great Lakes States and the Province of Ontario,

with help from Federal agencies and organizations, local

governments, industry, environmental groups, and

individuals. Although there has been significant progress in developing and implementing most RAPs

(including the delisting of the Collingwood Harbor AOC in Canada), considerable challenges remain. 
Chapter III

Major Programs and Activities

Page III-36 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Figure III-2

The 42 Areas of Concern in the Great Lakes Basin

Lake Superior

1. Peninsula Harbour

2. Jackfish Bay

3. Nipigon Bay

4. Thunder Bay

5. St. Louis Bay/R.

6. Torch Lake

7. Deer Lake-Carp Creek/R.

Lake Michigan

8. Manistique River

9. Menominee River

10. Fox River/Southern Green Bay

11. Sheboygan River

12. Milwaukee Estuary

13. Waukegan Harbor

14. Grand Calumet River/Indiana 

 Harbor Canal

15. Kalamazoo River

16. Muskegon Lake

17. White Lake

Source: Adapted from Hartig et al. 1997

Lake Erie

21. Clinton River

22. Rouge River

23. River Raisin

24. Maumee River

25. Black River

26. Cuyahoga River

27. Ashtabula River

28. Presque Isle bay

29. Wheatley Harbour

Lake Huron

18. Saginaw River/Saginaw Bay

19. Severn Sound

20. Spanish River

Lake Ontario

30. Buffalo River

31. Eighteen Mile Creek

32. Rochester Embayment

33. Oswego River

34. Bay of Quinte

35. Port Hope

36. Metro Toronto

37. Hamilton Harbour

Connecting Channels

38. St. Marys River

39. St. Clair River

40. Detroit River

41. Niagara River

42. St. Lawrence River 

 (Cornwall/Massena)
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-37

Current Status of LaMPs in the Great Lakes

Superior Binational Program to Restore and Protect the 

Lake Superior Basin announced (1991)

Stage 1 LaMP submitted to IJC (1995)

Stage 2 LaMP released (1999)

Stage 3 LaMP in development

Michigan LaMP published in Federal Register (1994)

Huron LaMP not established

Erie LaMP Management Committee formed (1994)

Ontario Lake Ontario Toxics Management Plan (1989)

LaMP Workplan signed (1993)

Stage 1 LaMP released (1998) 

One of the major problems facing the AOCs today is toxic contamination of sediments, contributing to

beneficial use impairments. 

Both the U.S. and Canadian

governments are charged with

developing LaMPs for each of the

Great Lakes, with the exception of

Lake Michigan. Because Lake

Michigan lies entirely within the

boundaries of the U.S., the Lake

Michigan LaMP was developed

solely by the U.S. government. The

LaMPs are in various stages of

development for each of the Great

Lakes (see sidebar). Not all of the

LaMPs have been completed;

however, commitments have been

made by key stakeholders in the

respective basins to pursue toxics

reductions and actions are being

taken to achieve these goals. Each LaMP addresses a different list of critical pollutants, commonly

including mercury, PCBs, hexachlorobenzene, dioxins, furans, chlordane, DDT and metabolites, and

dieldrin, all of which are Great Waters pollutants of concern.

The Lake Superior LaMP is unique in that it is being developed in stages. The Stage 1 LaMP

was submitted to the IJC in 1995. The Stage 2 LaMP, which addresses critical pollutants, is available on

EPA’s web site at www.epa.gov/grtlakes/lakesuperior/stage2lamp.html. The Stage 3 LaMP, which is

currently in development and is available as a review draft on EPA’s web site at

www.epa.gov/grtlakes/lakesuperior/stage3/review.html, addresses selection of remedial measures and

management strategies to achieve critical pollutant load reduction targets. 

LAKE CHAMPLAIN BASIN PROGRAM

Since the Second Report to Congress, the Lake Champlain Basin Program (LCBP) has continued

to develop and implement a comprehensive pollution prevention and restoration plan for the lake and its

watershed, as called for by the Lake Champlain Special Designation Act of 1990. In October 1996, the

LCBP finalized Opportunities for Action, An Evolving Plan for the Future of the Lake Champlain Basin

(LCBP 1996a, b). The final plan differs little from the draft plan, which was described in detail in the

Second Report to Congress. Environmental issues addressed by the plan include high phosphorus levels,

toxic substances (most notably PCBs and mercury) in biota and sediment, and invasive non-native

species. Atmospheric deposition of mercury to Lake Champlain basin is the subject of research efforts

described in Chapter II.

The LCBP supported and published several technical reports on the Lake Champlain basin and

the Lake Champlain ecosystem. For example, in October 1997, the LCBP published Phase II of the Lake

Champlain Sediment Toxics Assessment Program (McIntosh et al. 1997). The first phase, which was

discussed in the Second Report to Congress, accomplished a lakewide screening of surface sediments for

an array of organic and inorganic trace contaminants, more intensive evaluations at nine sites with

elevated contaminants levels, and an assessment of PCB bioaccumulation from sediment by the

macroinvertebrate Mysis relicta. Phase II further targeted investigations to the three most contaminated
Chapter III

Major Programs and Activities

Page III-38 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Chesapeake Bay Program Partners

P State of Maryland

P Commonwealth of Virginia

P Commonwealth of Pennsylvania

P District of Columbia

P Chesapeake Bay Commission

P U.S. EPA (representing all Federal 

 agencies, e.g., NOAA, U.S. FWS)

areas of the lake: Cumberland Bay, Malletts Bay, and Burlington Harbor. Results of the Phase II

investigation are presented in Chapter II above.

Other recent research projects sponsored by LCBP include development and compilation of

Geographic Information Systems data for the basin (VCGI 1996, Millette 1997); hydrodynamic and

water quality modeling and monitoring (ASA 1996, Lake Champlain Basin Program 1998); food web

modeling (LeBar and Parrish 1996); and, other ecological subjects. Numerous other LCBP-supported

publications address economic, educational, recreational, and other resource management subjects. 

Future research will focus on environmental indicators. In addition, the Lake Champlain Steering

Committee, which evolved from the Management Conference, includes the Province of Quebec as a

member. Involvement of Quebec will ensure that both U.S. and Canadian concerns are addressed.

CHESAPEAKE BAY PROGRAM

The Chesapeake Bay Program (CBP) is a unique

regional partnership (see sidebar) that has been responsible

for directing and implementing the restoration of the

Chesapeake Bay since 1983. Since that time, the highest

priority has been placed on restoring the living resources of

the bay, including finfish, shellfish, bay grasses, and other

aquatic life and wildlife. Examples of specific actions

undertaken by the CBP include agricultural best management

practices, pesticide collection and disposal programs, public

education, Biological Nutrient Removal at wastewater

treatment facilities, and a phosphate detergent ban (Chesapeake Bay Program 1998d). In addition, the

CBP is working with NOAA’s Chesapeake Bay Environmental Effects Committee which supports

research on contaminated sediment to better understand issues related to the management of

contaminated sediments. 

As discussed in the Second Report to Congress, the 1994 Chesapeake Bay Basinwide Toxics

Reduction and Prevention Strategy is an integral part of the CBP. The primary goal of the strategy is a

“Chesapeake Bay free of toxics by reducing or eliminating the input of chemical contaminants from all

controllable sources to levels that result in no toxic or bioaccumulative impact on the living resources

that inhabit the bay or human health.” The strategy contains commitments in the following five areas: (1)

regional focus – calls for assessing the status of chemical contaminant effects on the living resources of

the bay and its tidal waters and implementing reduction and prevention activities in those areas; (2)

directed toxic assessments – calls for the characterization of chemical contaminant conditions in the bay,

the assessment of low level toxics exposure to living resources as well as the update of the Toxics

Loading and Release Inventory to identify toxics sources; (3) regulatory program integration – calls for

Chesapeake Bay Program activities to complement and enhance Federal, State, and local regulatory

programs; (4) pollution prevention – includes facility-based pollution prevention, pesticide management,

and consumer/household hazardous waste activities and goals; and, (5) strategy implementation –

outlines how the strategy will be implemented. 

The strategy addresses non-point source pollution, committing the CBP signatories to “establish

more complete loadings baselines and source identification for storm water runoff, atmospheric

deposition, and acid mine drainage, and set reduction targets from that baseline to be achieved over the

next decade.” The CBP will use the updated 1999 Chesapeake Bay Basinwide Toxics Loading and

Release Inventory, which provides updated chemical contaminant loadings estimates for atmospheric
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-39

Reducing Pesticide Use in the Chesapeake Bay

Watershed

The CBP has been working toward goals to reduce

pesticide use in the Chesapeake Bay watershed. 

Recent accomplishments include the following:

U Pesticide collection and disposal programs have

been offered in all Virginia and Pennsylvania

counties and 75 percent of Maryland counties in the

watershed. Over 1.1 million pounds of pesticides

have been collected;

U Between 1993 and 1998, nearly 600,000 pesticide

containers have been collected and recycled.

U Integrated Pest Management is now used on

nearly 4.4 million acres (61 percent) of agricultural

cropland in the watershed.

deposition and other point and non-point sources

to address this commitment. The inventory

reports atmospheric deposition loads from

chemical contaminants in the air that are

deposited onto the bay and its tidal rivers. These

estimates are updated and expanded using recent

field measurements and improved theoretical

understanding of deposition processes. 

Volatilization of organic contaminants from the

surface waters to the air is considered for the

first time in calculating a “net” atmospheric

loading to the bay and tidal rivers. Initial

estimates of the contribution of urban areas to

atmospheric deposition loads to the bay and tidal

rivers are also reported. Only loads to tidal

waters (below the fall line) are reported. The

TRI database for industrial air releases was not

included in this inventory, as it was in 1994,

since the improved and expanded atmospheric loadings data (to tidal waters) are based on measured data

and are a much better representation of loads than the TRI data estimates of releases. The inventory

reports that atmospheric deposition loads to the tidal waters increase in areas of the bay and tidal rivers

adjacent to urban areas (Chesapeake Bay Program 1999a).

To focus toxic reduction and prevention efforts, the CBP developed a list of Chesapeake Bay

toxics of concern (i.e., chemicals that cause or have a potential to cause adverse impacts on the bay

system, such as mercury, PAHs, and PCBs -- see

sidebar). By 2000, the CBP is directed to

reevaluate and revise the 1994 toxics strategy. 

Future plans for the Chesapeake Bay Program

include research in support of regional action

plans for areas with known toxics problems, with

a particular emphasis on how to deal with

contaminated sediment. In addition, data

collected over the past decade will continue to be

analyzed to determine which chemicals have been

detected in water, sediment, shellfish, and finfish

to identify other toxics problems in the bay

(Chesapeake Bay Program 1998c). 

Nitrogen reduction in the bay is an

ongoing focus of the CBP. Recent modeling efforts indicate that approximately 21 percent of the

nitrogen entering the bay is from atmospheric deposition. Therefore, the CBP is working to quantify and

address atmospheric nitrogen and toxics emissions and sources along with their associated impacts on the

bay resources. A current effort involves assessing the benefits that will be experienced due to the

implementation of the CAA. The CBP is also supporting scientific research which is being conducted to

better understand the integrated, multimedia relationships of the ecosystem. In addition, the Chesapeake

Bay Program is developing a strategy to better understand and quantify the various forms of nitrogen

which may be affecting living resources and water quality in the Chesapeake Bay. Part of an integrated

basinwide monitoring effort, this strategy will help to fill in gaps in our knowledge of atmospheric

Chesapeake Bay Program Toxics of Concern

Atrazine

Benz[a]anthracene 

(PAH)*

Benzo[a]pyrene (PAH)*

Cadmium

Chlordane*

Naphthalene (PAH)*

Tributyltin

Chromium

Chrysene (PAH)*

Copper

Fluoranthene (PAH)*

Lead*

Mercury*

PCBs*

* Great Waters pollutants of concern
Chapter III

Major Programs and Activities

Page III-40 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Growing Attention to Sources of Ammonia and

Urea to the Chesapeake Bay

Ammonia and urea are other forms of nitrogen that

are receiving increased attention from researchers

and regulatory agencies, in part because these forms

are more biologically available. One of the sources

of ammonia and urea is manure from animal farming

operations. With the increase in animal farming in

the bay watershed and surrounding States,

particularly hog and poultry farming, it is important to

investigate pollutant emissions to the air and the

distances they travel in the air before being deposited

to land or water surfaces. The CBP sponsored a

workshop on atmospheric organic nitrogen (e.g.,

urea) and is coordinating with NOAA to determine

atmospheric concentrations of ammonia, estimate

ammonia deposition to land and water surfaces, and

evaluate the importance of ammonia transport and

deposition. 

deposition of nitrogen compounds, focusing in the near term on measuring deposition of ammonia and

ammonium in the coastal areas (Chesapeake Bay Program 1998a). 

In addition, recent actions taken under the Clean Water Act resulted in listing portions of the

Chesapeake Bay and its tidal rivers as impaired waters. These actions have emphasized the regulatory

framework of the Clean Water Act along with the ongoing cooperative efforts of the Bay Program as the

means to address the nutrient enrichment problems within the Bay and its rivers. In response, the Bay

Program partners have committed to a process for integrating the cooperative and statutory programs of

the Chesapeake Bay and its tributaries. In the new Chesapeake Bay Agreement, the partners are

committed to developing goals for improving water quality in the Bay and its tributaries so these waters

may be removed from the impaired waters list prior to the timeframe when regulatory mechanisms under

section 303(d) of the Clean Water Act would need to be applied.

The CBP is helping bay partners to incorporate air pollution impacts in the management of 

lakes, rivers, and streams. For example, the CBP is encouraging States to account for air deposition in

TMDL development (for background information on TMDLs, see the TMDL discussion on page III-5)

and helping bay States account for atmospheric deposition of nitrogen compounds in developing tributary

strategies to protect the bay. Tributary strategies are “clean-up plans” for each major river that flows into

the bay. The Commonwealth of Virginia is developing tributary strategies for their southernmost bay

tributaries, and the CBP is providing modeled information on how different management scenarios for

atmospheric nitrogen emissions will affect deposition loads. This will give States an idea of different

options for cleaning up lakes, rivers, and streams. For example, an understanding of how much nitrogen

will not enter the bay by implementing certain air controls will allow States to count the cost of all of the

options of reducing nitrogen inputs. In comparing methods of nutrient reduction in waters in the

Chesapeake Bay area, it may be that cleaning up the air is more cost-effective than some water-based

controls, such as additional storm water management in cities. 

Despite the progress made to date in reducing inputs of nitrogen to the Chesapeake Bay, the

Chesapeake Executive Council announced that unless current efforts are accelerated, the nitrogen

reduction goal of the Chesapeake Bay Agreement will not be met by the year 2000. In 1997, the

Executive Council developed three new directives to accelerate the reduction of nitrogen inputs to the

bay.

1. The Baywide Nutrient Reduction

Progress and Future Reductions

directive outlines a series of actions

aimed to further commitments made in

the Chesapeake Bay Agreement. One of

the actions is to “Work toward additional

reductions of airborne nitrogen delivered

to the Bay and its watershed from all

sources including States outside the

watershed, and seek improved

understanding of how airborne nitrogen

affects the Bay and its watershed..” The

directive includes a time line for

completing refinements of computer

modeling as well as water quality

monitoring. Outputs from monitoring

and modeling efforts will be used to help
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-41

set nutrient goals for Virginia tributaries and to develop a protocol to determine whether nutrient

reduction efforts can be further targeted to areas of persistent high loadings. 

2. The Wetlands Protection and Restoration Goals directive provides quantifiable wetland

restoration goals to assure no net loss of wetlands and to move in the direction of a net gain of

wetland areas.

3. The Community Watershed Initiative will develop a community watershed strategy to ensure

that Chesapeake Bay Program goals and objectives are integrated at the community watershed

scale (Chesapeake Bay Program 1998b). 

GULF OF MEXICO

PROGRAM

The Gulf of Mexico Program

emphasizes community-based,

ecosystem management approaches to

environmental protection, including 

(1) equal partnership among

government agencies and private and

non-government interests to define

problems and implement solutions, (2)

use of the best science and knowledge

available to support decisions and

guide actions, and (3) public

involvement in all phases of the

program to generate the consensus

needed for action. The Gulf of

Mexico Program is not a regulatory

program, although some of the partner

agencies at the Federal and State

levels have regulatory responsibilities. 

The program provides a forum whereby issues that cross political or social boundaries can be clearly

identified, discussed, and collaboratively resolved to benefit the ecological and economic resources of

the Gulf of Mexico. 

Given the vast geographic scope of the gulf, protection of these critical resources requires a longterm commitment and focused attention. A strategic assessment process is being implemented to focus

future efforts, identify resources at greatest risk, and establish quantitative goals to measure progress. 

Currently, the Gulf of Mexico Program is addressing four priority environmental concerns, two of which

are relevant to the Great Waters program: (1) protecting the public from contaminated shellfish and

recreational waters, and (2) excessive nutrient enrichment.

Excessive nutrient enrichment is attributable to a multitude of terrestrial and atmospheric sources

throughout the Gulf States and the watersheds (e.g., the Mississippi River basin) that drain into the gulf. 

The Gulf of Mexico Program, as a multiagency effort, is working with State and community partners on

several projects to protect the gulf from the deleterious effects of nutrient enrichment. 
Chapter III

Major Programs and Activities

Page III-42 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

NEPs Conducting 

Atmospheric Deposition Studies

g Albemarle-Pamlico Estuary (NC)

g Casco Bay (ME)

g Charlotte Harbor (FL)

g Coastal Bend Bay and Estuary (TX)

g Delaware Inland Bays (DE)

g Indian River Lagoon (FL)

g Long Island Sound (NY, CT)

g Massachusetts Bay (MA)

g Maryland Coastal Bays (MD)

g Mobile Bay (AL)

g New York/New Jersey Harbor (NY, NJ)

g Peconic Bay (NY)

g San Francisco Bay (CA)

g Santa Monica Bay (CA)

g Sarasota Estuary (FL)

g Tampa Bay (FL)

For example, the Gulf of Mexico Program is working with the Gulf States to address nutrient

enrichment problems in the gulf, such as a zone of hypoxia along the Louisiana coast. Hypoxia in the

northern gulf represents one of the largest zones of oxygen-deficient bottom waters in the western

Atlantic Ocean. Nitrate and other nutrients discharged from the Mississippi River are the probable cause,

making agricultural and municipal runoff and atmospheric deposition potential sources to investigate. 

In addition, the Gulf of Mexico Program is supporting two initiatives of a multiagency scientific

team established by the White House’s Committee on Environment and Natural Resources (CENR). In

particular, the Gulf of Mexico Program is supporting studies to characterize the ecological and economic

consequences of hypoxia in the gulf and nutrient sources and loads to the gulf from the Mississippi

River. Further discussion of the CENR process can be found in Chapter IV of this report.

NATIONAL ESTUARY PROGRAM

Coastal waters addressed by the Great Waters

program include all estuaries covered by the National

Estuary Program (NEP). In 1987, Congress established the

NEP as part of the Clean Water Act. The NEP’s mission is

to protect and restore the health of the estuaries while

supporting economic and recreational activities. The EPA

periodically calls for nominations of estuaries to the NEP

from State governors. If an estuary meets the Agency’s

criteria, EPA may then designate it as an estuary of national

significance. As depicted in Figure I-2, there are currently

28 estuaries around the country and in Puerto Rico in the

National Estuary Program. 

To date, at least 19 NEPs have identified

atmospheric deposition of pollutants as a threat to the health

of their estuaries. Many of these NEPs either have initiated

studies on the contribution of atmospheric deposition to

annual loadings of nitrogen and/or other pollutants, or have

expressed serious interest to EPA in conducting such

projects. In 1999, EPA provided funds to establish new

atmospheric deposition monitoring sites in five NEPs, expanding the National Atmospheric Deposition

Network in the coastal waters and improving the ability to compare coastal data to data collected from

inland sites. Peconic Bay NEP and Maryland Coastal Bays NEP are monitoring for nitrogen and sulfur

compounds, San Francisco Bay is monitoring for mercury compounds, and Mobile Bay NEP is

monitoring for sulfur, nitrogen, and mercury compounds. In addition, a site measuring dry deposition of

sulfur and nitrogen compounds (part of the CASTNet monitoring network) is being established near

Indian River Lagoon NEP. The following describes other NEP sites and their associated atmospheric

deposition research activities to date.

C Albemarle-Pamlico Estuary (NC). Nitrogen deposition studies in eastern North Carolina are

primarily focusing on the emissions and deposition of ammonia. Concern has been spurred by

the explosive growth of large-scale hog farming operations in the coastal plain over the last few

years. For example, long-term analysis of National Atmospheric Deposition Program (NADP)

data from a site near the center of an intensive animal operations (i.e., Sampson County, NC)

indicate at least a doubling of NH4

+

 deposition since the early 1980s (Paerl 1997b). Monitoring

efforts led by researchers from the University of North Carolina at Chapel Hill (UNC-CH) and
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-43

North Carolina State University (NCSU) are aimed at quantifying atmospheric levels of both gas

and aerosol forms of ammonia to aid in the development of regional-scale, air quality models

(Robin Dennis, NOAA/EPA). Monitoring began in fall 1998, but data obtained in the 1999

summer season will be critical in understanding seasonal emission and deposition patterns. 

Additional efforts are aimed at developing nitrogen budgets for the Neuse River basin. These

projects began with State funding and, when completed, will put the atmospheric contribution

into the context of the overall nitrogen load to the Neuse River basin (W. Robarge, NCSU; H.

Paerl, UNC-CH). The EPA is also funding research to examine the biological ramifications (e.g.,

eutrophication) of atmospheric nitrogen inputs in the Neuse River basin and the adjacent coastal

waters.

C Casco Bay (ME). The Casco Bay Air Toxics Deposition Study, begun in 1998, is a multiyear

collaborative effort by the Casco Bay Estuary Project, the Maine Department of Environmental

Protection, EPA Region I, and university research scientists (University of Massachusetts,

Lowell). The study focuses on atmospheric deposition of five contaminant groups (i.e., mercury,

toxic trace elements, PAHs, nitrogen, and fine particulates) and is funded by the Great Waters

program as part of the national strategy to determine the environmental health and status of key

NEP ecosystems. The objectives of the study are to characterize seasonal and annual

depositional patterns of toxic air compounds to Casco Bay and to develop a generic assessment

method that can be used by other community-based programs.

• Charlotte Harbor (FL). The Charlotte Harbor NEP atmospheric deposition study received

funding in 1999 and will begin activities in 2000.

C Coastal Bend Bay and Estuary Program (TX). The concentrations of nutrients and organic

contaminants (including PAHs, PCBs, and some pesticides) in wet and dry atmospheric

deposition is being measured or calculated at two representative sites on Corpus Christi Bay. An

EPA grant expanded the pollutants measured at one station to include organic contaminants. The

wet nutrient deposition data are comparable to other air monitoring programs, including the

NADP, but this is one of the only NEP studies that measures the deposition rate of organic

contaminants. This study is being conducted in conjunction with other studies in the area

(including EPA’s Environmental Monitoring and Assessment Program (EMAP) and NOAA’s

National Status and Trends Program) to measure the inputs to the bay and estuary of organic

pollutants, trace metals, and nutrients from other sources (e.g., other non-point sources, point

sources). This will allow the Coastal Bend Bay and Estuary Program to calculate the importance

of atmospheric deposition for each pollutant and target control measures where they are most

effective.

C Delaware Inland Bays (DE). The University of Delaware Graduate College of Marine Studies

is undertaking three studies to address atmospheric deposition issues related to the Delaware

Inland Bays. The first study, currently in progress and funded by the Delaware Department of

Natural Resources and Environmental Conservation (DNREC), has two primary objectives: (1)

to accurately quantify the atmospheric loading of nitrogen to the Delaware Inland Bays; and (2)

to assess, in cooperation with the University of Delaware Center for Climatic Studies, the

meteorological transport patterns which contribute to the observed nitrogen deposition. The

second study, also funded by the DNREC, will examine the episodic impact of large precipitation

events on the loading of nitrogen to the Delaware Inland Bays by both direct (deposition to the

water surface) and indirect (via watershed transmission) pathways. 
Chapter III

Major Programs and Activities

Page III-44 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

The third study, which is funded by the EPA National Estuary Program, will address the impacts

of local sources (e.g., a coal-fired power plant, poultry-rearing facilities) on nitrogen deposition

to the Delaware Inland Bays and distinguish the impacts of local sources from the impacts of

regional sources. Research to date indicates a 60 percent increase in the wet deposition of

ammonia over the past two decades. Although the explanation is uncertain, the working

hypothesis is that the increase is related to the large increase in poultry production on the

Delmarva Peninsula. The NEP grant will test this hypothesis. An analogous situation exists in

coastal North Carolina where the approximate doubling of the concentration of ammonia in

precipitation over the past 10 years has been attributed to the proliferation of hog farms in the

region (Paerl 1997b). Such increases in atmospheric ammonia deposition are not only important

because of the additional sources of nitrogen to surface waters, but also because ammonia

represents the most readily-available form of nitrogen for most aquatic organisms.

C Long Island Sound Estuary Program (NY, CT). The Long Island Sound Study (LISS) Estuary

Program has been evaluating atmospheric nitrogen sources leading to the development of a final

nitrogen control plan. Wet and dry deposition monitoring studies have expanded in recent years

through a cooperative effort with the Connecticut Department of Environmental Protection

(CTDEP) and the University of Connecticut (UConn). The UConn now maintains eight

sampling stations spread throughout Connecticut where wet and dry monitoring of nutrients and

mercury is conducted. The data have been key to estimating nitrogen deposition loads, which are

about 10 lb/acre-year in the Long Island Sound region. The anthropogenic component of the

atmospheric deposition delivered to Long Island Sound is estimated to be around 6,700 tons of

nitrogen annually including about 3,700 tons that fall directly on the sound. This combined

direct and indirect deposition represents about 15 percent of the total load of nitrogen to Long

Island Sound from the New York and Connecticut portions of the watershed. Additional

nitrogen loadings come from atmospheric deposition onto the Long Island Sound drainage basins

north of Connecticut, the watersheds of the New York/New Jersey Harbor and Narragansett Bay,

and from direct deposition on the Atlantic Ocean that currents transport into Long Island Sound. 

In February 1998, the States of New York and Connecticut and EPA agreed to a reduction target

of 58.5 percent below a 1990 baseline for point and terrestrial non-point source enrichment. 

While achieving that target will greatly improve oxygen conditions in the sound, it will not attain

existing State water quality standards for dissolved oxygen. In a TMDL analysis being prepared

by Connecticut and New York, additional actions are identified, including atmospheric

reductions of nitrogen planned under the CAA. The analysis identifies that reducing atmospheric

sources of nitrogen will be key to long term efforts to attain water quality standards.

• Massachusetts Bays (MA). Wet and dry deposition of toxic compounds, including metals and

PAHs, were measured from September 1992 to September 1993 at two sites, one in the northern

bay and one in the southern bay on Cape Cod. Dry deposition was greater at the northern site

(close to Boston) for most metals. Wet deposition, on the other hand, was greater at the southern

site for the metals. The high dry deposition rates at the northern site are probably due to its

proximity to Boston. The high wet deposition rates on Cape Cod are probably from sources

upwind in southern New England, New York, and New Jersey. Both dry and wet deposition of

PAHs were higher at the northern site, also probably from sources in the Boston metro area,

including Logan Airport. Dry deposition was highest at both sites in the winter. No PCBs were

found at either site.

Wet nitrogen deposition data from four regional (three in Massachusetts and one in coastal

Maine) NADP sites were also analyzed from the early 1980s (1980, 1981, or 1982, depending on

the site) through 1993. Dry deposition data were collected from a literature search. Direct
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-45

deposition to the bays was estimated to be 6-8 percent of the total nitrogen load. Approximately

two-thirds were in the form of wet deposition. The percentage of nitrogen in the surface layer,

where a large portion of the biological activity occurs, was also estimated in an attempt to

quantify the biological availability of atmospherically deposited nitrogen. Direct deposition was

estimated to be approximately 2 percent of this surface-layer nitrogen during the winter months.

However, this is probably the lowest percentage that occurs during the year, and deposition may

be an important source of nitrogen in the summer months. Uncertainties related to in situ dry

deposition sampling and wet dissolved organic nitrogen sampling require additional research.

C New York/New Jersey Harbor Estuary Program (NY, NJ). New York-New Jersey Harbor is

currently the focus of several studies relating to sources of nutrient and toxic pollution loadings

to the harbor. These studies will help to quantify pollutant loadings under the TMDL

determination. As part of that effort, four air deposition monitoring stations were set up in the

harbor area for limited monitoring for PCBs, PAHs, dioxin, heavy metals, and nitrogen. This

information will then be available to determine the total loadings of contaminants that are not

meeting criteria from all sources. Control options for meeting the TMDLs may include a

reduction of air sources. This work is being conducted in cooperation with the New Jersey

Department of Environmental Protection and the Hudson River Foundation.

C San Francisco Estuary (CA). The San Francisco Estuary Project (SFEP) is working with the

Bay Area Stormwater Management Agencies Association (BASMAA) to identify sources of air

emissions resulting in deposition of pollutants onto the land and to quantify the contribution of

air pollutants reaching the estuary in storm water runoff. The pollutants of concern are primarily

toxics, including copper, mercury, PCBs, and PAHs. This study is being coordinated with the

San Francisco Estuary Regional Monitoring Program for Trace Substances (see page II-76). The

San Francisco Estuary Institute (SFEI) coordinates the Regional Monitoring Program, which

includes water, sediment, and tissue monitoring and is now being expanded to monitor air

deposition. The SFEI is conducting a pilot study to evaluate pollutants which are being

deposited from the air directly onto the estuary waters. Based on these studies, local and State

agency partners will be able to assess the cost-effectiveness of emission reduction options and

quantify the benefits associated with emission reduction strategies. 

C Santa Monica Bay (CA). The Santa Monica Bay NEP has proposed an air transport/deposition

study to (1) quantify emissions of the toxic materials and nitrogen in the Los Angeles air basin

that are subsequently deposited in the bay and its watershed; (2) identify pollutant sources and

their relative contributions to total pollutant loading to the bay; and, (3) evaluate the relative

impacts of air deposition and the benefit of various emission reduction options in order to

recommend the most cost-effective measures to control the identified sources. Initially, the Santa

Monica Bay study will quantify the wet and dry toxic and nitrogen deposition to the bay surface. 

Indirect deposition over the landscape will be calculated using a model developed locally for the

region that uses air concentrations, local meteorology, and surface types (trees, pavement) to

calculate deposition velocities and loadings. This study will measure air concentrations over

water, a difficult process that is not often done but that is necessary to improve the understanding

of direct deposition processes. The study will also measure the impact of air deposition during

“events” (fire storms, rain storms, Santa Ana winds) to understand how these weather patterns

contribute to local air deposition.
Chapter III

Major Programs and Activities

Page III-46 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

C Sarasota Estuary (FL). The Sarasota Bay NEP is involved in four large research projects.

Atmospheric Monitoring Site on Sarasota Bay. For the average rainfall year, it is estimated that

atmospheric deposition directly to the water surface provides 26.5 percent of the total nitrogen

load to the bay. Under cooperative agreements with EPA, the Southwest Florida Water

Management District (SWFWMD), and local governments, the Sarasota Bay NEP initiated an

intensive, 1-year atmospheric deposition monitoring effort (within the national NADP/AIRMoN

program) in September 1998. The intensive monitoring program is designed to establish

relationships between emission sources or source regions and deposition to specific receptors. 

Atmospheric Transport and Dispersion Model. Preliminary modeling by EPA using the

Regional Atmospheric Deposition Model (RADM) at an 80 km grid suggested that 70 percent of

the atmospheric nitrogen deposited to Sarasota Bay may originate from outside the watershed. 

Therefore, the Sarasota Bay NEP contracted with the University of South Florida to develop a

regional atmospheric transport and dispersion model to determine the impact of NOx emissions

on Sarasota Bay water quality. Investigators modeled atmospheric dispersion, transport,

chemical transformation, and deposition of NOx, nitric acid, and nitrate from stationary and

mobile sources using CALMET/CALPUFF, a Lagrangian puff model. A regional domain of 250

km by 500 km with a 20 km grid was modeled and included emissions from the metropolitan

areas of Tampa, Orlando, Miami, and Fort Myers. The model indicated that Sarasota Bay shared

the same airshed as Tampa Bay and the airshed encompassed the entire modeling domain. The

model further indicated that mobile source emissions may be responsible for the majority (81

percent) of atmospheric nitrogen sources to Sarasota Bay. One caveat of the modeling, however,

was that modeled wet deposition was approximately a factor of five lower than measured fluxes. 

Furthermore, utilities were found to contribute disproportionately to wet deposition. Therefore,

the total contribution of utilities to atmospheric deposition may be underestimated and that of

mobile sources may be overestimated.

Biological Effects of Atmospheric Deposition. Areas of the Sarasota Bay that receive the greatest

percentage of nitrogen loading from atmospheric sources are also associated with the highest

water quality; however, total nutrient loads to these segments are lower. Therefore, an

investigation of the effects of atmospheric deposition on algal assemblages was initiated by the

Sarasota Bay NEP through cooperative funding by SWFWMD and is being conducted by Mote

Marine Laboratory. The growth response of phytoplankton to rainwater and nutrient additions is

being determined by changes in major taxon composition, changes in particle size distribution,

and through high performance liquid chromatography of photosynthetic pigment composition. 

The final results of this study should yield information on the major taxon composing a nutrientrich (nearshore) and nutrient-depleted (offshore) algal regime, changes in growth rates as a result

of rainfall and nutrient additions, and the potential of rainfall to act as a trigger for algal blooms

in each regime. This research should provide information on the biological effects of

atmospheric deposition.

Stable Isotopes to Trace Nitrogen Sources. This on-going study funded by EPA will use stable

nitrogen isotope ratios (15N/14N) to determine the relative contributions of different types of

sources (e.g., wastewater treatment plant effluent, fertilizer runoff, animal waste, and combustion

processes), including air deposition of nitrogen. Both nitrogen isotopes are naturally-occurring,

but the ratio of 15N/14N varies depending on the source. Measuring the ratio in emissions from

different sources, in rainwater (wet deposition), and in phytoplankton, macroalgae, seagrasses,

and the water column will help researchers identify the sources of atmospherically-deposited
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-47

nitrogen and its effects once it reaches the estuary. This is the only NEP air deposition study that

measures nitrogen in the food web. 

C Tampa Bay Atmospheric Deposition Projects (FL). The EPA and its partners in the Tampa

Bay NEP (TBNEP) are currently working on eight separate but related projects to characterize

the sources and impacts of atmospheric deposition to Tampa Bay and its watershed. A brief

summary and status for each of these projects follows:

(1) An intensive monitoring site, sponsored by TBNEP and EPA’s Great Waters program,

was created to quantify nitrogen loading from atmospheric deposition to the surface of

Tampa Bay, estimate relative contributions from wet and dry deposition, assess temporal

variability of wet and dry deposition, and assess the relative contribution of different

nitrogen species to atmospheric deposition in Tampa Bay. Preliminary results indicate

that atmospheric deposition directly to the bay’s surface accounts for approximately

one-third of the new nitrogen delivered from all sources to the bay. 

 

(2) The TBNEP initiated a study to estimate the contribution of atmospherically-deposited

nitrogen to storm water loading from residential basins and estimate attenuation of

nitrogen from atmospheric deposition in residential basins. The results indicated that

approximately 15-20 percent of atmospherically-derived nitrogen was discharged from

these basins per rainfall event.

(3) Toxic materials sampling, sponsored by TBNEP, EPA, Florida Department of

Environmental Protection (FDEP), and the Environmental Protection Committee of

Hillsborough County (EPCHC), is being initiated to quantify metal concentrations and

other contaminants in ambient air and to estimate potential loadings to water and the

watershed.

(4) The TBNEP and the Great Waters program will fund ammonia sampling to map the

pattern of ambient air ammonia concentrations. Initial results from a pilot study indicate

a strong gradient in ambient ammonia from the highly industrialized east bay to

background levels at the existing intensive monitoring site. The overall objective is to

develop a surface map showing relative concentrations of ammonia across the northern

Hillsborough Bay area.

(5) Beginning in the fall of 1998, the FDEP funded a study in which the Florida State

University and the University of Virginia used N-isotopic ratios to identify nitrogen

source types affecting Tampa Bay. In particular, the researchers are using isotopic ratios

to attribute the relative contribution from different source types to atmospheric nitrogen,

including combustion engines, coal-fired power plants, and diesel engines. 

(6) Local governments and the TBNEP have cooperatively developed and are operating a

long-term spatial monitoring network for atmospheric deposition in the Tampa Bay

region. The purpose of the monitoring network is to track the contribution and temporal

trends of atmospheric nitrogen loading throughout the region. 

(7) The EPA is using RADM to identify relative contributions to nitrogen deposition in

Tampa Bay from near and far sources. This effort also examines deposition to the bay

and watershed. 
Chapter III

Major Programs and Activities

Page III-48 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

(8) In 1999, the FDEP is scheduled to initiate the Bay Regional Atmospheric Chemistry

Experiment (BRACE) to (1) refine estimates of annual deposition of nitrogen species

(HNO3, NH3, NH4NO3) to Tampa Bay and its watershed; (2) predict urban ambient ozone

and PM2.5 concentrations; and, (3) estimate contributions of primary emissions from

motor vehicles and stationary sources. This project will include high resolution

deposition-daily event samples analyzed for nutrients and trace metals (including

mercury), and a 1-year field monitoring program using a Differential Optical Absorption

Spectrometer to measure sulfur dioxide, ozone, nitric oxide, nitrogen dioxide or nitrite,

benzene, toluene, organics, metals, pesticides, and xylenes.

NOAA ACTIVITIES

National Estuarine Research Reserve System

Under the 1972 Coastal Zone Management Act, Congress created the National Estuarine

Research Reserve System (NERRS) to enhance the scientific understanding and management of the

Nation’s estuaries and coastal habitats. The NERRS is a network of protected estuarine areas in which

Federal, State, and local partnerships work to promote stewardship, education, and research. As of

1999, 23 reserves were designated as NERRS sites, encompassing about 960,000 acres of estuarine

waters, wetlands, and uplands. Four additional sites have been proposed and are in the process of

development and designation. See Figure I-2 for the location of NERRS sites. All NERRS estuaries are

included in the definition of “Great Waters.”

The NOAA’s Estuarine Reserves Division is working with all NERRS sites to implement a

System-wide Monitoring Program (SWMP) to track the status and trends in coastal ecosystem health. 

This national monitoring program will be coordinated with other national and regional programs (i.e.,

NEP, EMAP, National Status and Trends). The overall goal of SWMP is to identify and track short-term

variability and long-term changes in the integrity and biodiversity of representative estuarine ecosystems

and coastal watersheds for the purpose of contributing to effective national, regional, and site specific

coastal zone management.

Currently, SWMP is focusing on compiling water quality and weather data. Within 22 reserves

in the system (Kachemak Bay NERR, Alaska was designated in February 1999 and is not yet

implementing SWMP), two locations – one non-impacted (baseline) and one non-point source impacted –

are designated as water quality monitoring sites where water quality parameters are measured every 30

minutes. In addition, meteorological data collection began at each NERRS site in February 1998 to

allow local weather events to be related to water quality conditions (NOAA NERRS 1998). Although

SWMP does not include atmospheric deposition monitoring, it will provide data useful for tracking the

ecological health of the coastal Great Waters.

Assessing Relative Nitrogen Inputs to Coastal Waters From the

Atmosphere

With funding from EPA’s Office of Water and Great Waters program, NOAA’s Air Resources

Laboratory (ARL) is performing a comprehensive assessment of nitrogen deposition to estuaries. In

1998, NOAA held two workshops involving experts from government, academia, and other institutions to

assemble and evaluate nitrogen deposition data and assessment procedures for approximately 40

estuaries on the Atlantic and Gulf of Mexico coasts. Workshop participants evaluated the adequacy of

existing nitrogen deposition data and attempted to develop standard nitrogen loading and mass balance
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-49

assessment methods. Standard assessment methods are needed to improve comparisons between studies

and locations. The report is being produced in 2000. 

Coastal Zone Management Program

The Coastal Zone Management Act of 1972 established the national coastal zone management

(CZM) program, a voluntary partnership between the Federal government and the coastal States and

territories of the U.S., with the following goals:

C Preserve, protect, develop, and (where possible) restore and enhance the resources of the

Nation’s coastal zone for this and succeeding generations;

C Encourage and assist the States and tribes to effectively exercise their responsibilities in the

coastal zone to achieve the wise use of land and water resources of the coastal zone, giving full

consideration to ecological, cultural, historic, and aesthetic values as well as the needs for

compatible economic development; 

C Encourage the preparation of special area management plans to provide increased specificity in

protecting significant natural resources, reasonable coastal-dependent economic growth,

improved protection of life and property in hazardous areas, and improved predictability in

governmental decision making; and,

C Encourage the participation, cooperation, and coordination of the public, Federal, State, tribal,

local, interstate, and regional agencies and governments affecting the coastal zone.

Since 1974, at least 32 Federally-approved CZM State programs have protected more than 99 percent of

the Nation’s 95,000 miles of oceanic and Great Lakes coastline. 

As a component of the overall CZM effort, NOAA and EPA are currently developing a Coastal

Non-Point Pollution Control Program for each CZM State program. The EPA has created pollution

management and control measures for five non-point source categories: agricultural runoff, urban runoff,

forestry runoff, marinas, and hydromodification.

OZONE TRANSPORT COMMISSION (OTC)

Section 184 of the CAA delineates a multistate ozone transport region (OTR) in the Northeast

and requires specific additional NOx and VOC controls for areas in this region, including attainment

areas. In addition, section 184 of the CAA established the Ozone Transport Commission (OTC) to assess

the degree of ozone transport in the OTR and to recommend strategies to mitigate the interstate transport

of pollution. States in the OTR include Connecticut, Delaware, Maine, Maryland, Massachusetts, New

Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, parts of northern Virginia,

and the District of Columbia. The OTC has concluded that regional reductions of NOx emissions are

particularly important in reducing ozone. 

To further control NOx emissions in the OTR, the OTR States agreed to implement RACT on

major stationary sources of NOx and to a phased approach for additional controls, beyond RACT, for

power plants and other large fuel combustion sources. This agreement, the OTC Memorandum of

Understanding (MOU) for stationary source NOx controls, was approved on September 27, 1994. All

OTC States, except Virginia, are signatories to the MOU. The MOU establishes an emissions trading
Chapter III

Major Programs and Activities

Page III-50 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

system to reduce the costs of compliance with the control requirements. In addition, in developing State

budgets for the NOx SIP call, EPA considered the NOx reductions each OTR State committed to in the

MOU. 
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-51 Minnesota Sea Grant, Jeff Gunderson

III.C STATE, LOCAL, AND TRIBAL ACTIVITIES

This section describes State, local, and tribal activities that will make significant contributions to

understanding or reducing atmospheric deposition of toxic air pollutants to the Great Waters. Unlike the

regional and waterbody-specific programs and activities described in Section III.B, these programs are

led by State, local, or tribal agencies, not Federal agencies. However, EPA and other Federal agencies

are partners in some of the programs. 

STATE AND LOCAL ACTIVITIES

The projects described below are examples of State and local projects that support the goals of

the Great Waters program. It is likely that there are many additional relevant State and local programs

that were not identified for this report.

Ammonia Study in North Carolina: An Example of Progress in

Understanding

The State of North Carolina recognizes nitrogen enrichment and eutrophication as a serious

environmental concern for certain coastal plains, nitrogen-sensitive estuaries, and coastal waters (see, for

example, the discussion of the Albemarle-Pamlico Estuary on page III-42). Atmospheric emissions and

deposition of ammonia from intensive livestock operations are the subject of particular attention, in

addition to atmospheric nitrates and water-borne discharges and runoff. A workshop on atmospheric
Chapter III

Major Programs and Activities

Page III-52 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

nitrogen compounds was held at North Carolina State University (NCSU) in March 1997 (Aneja et al.

1998). 

The State of North Carolina Department of Environment and Natural Resources, in conjunction

with NCSU, University of North Carolina at Chapel Hill, U.S. Department of Agriculture, and EPA, has

begun a coordinated research program on ammonia emissions from large-scale livestock operations, and

on the transport and deposition of ammonia, with possible effects of eutrophication in aquatic systems

and on forest and crop production. Ammonia and other NHx compounds have much different

atmospheric lifetimes and interactions in the environment than do oxidized nitrogen compounds or NOx

(primarily NO and NO2). The research program on nitrogen compounds will quantify the emissions,

verify or improve existing emission factors, and begin modeling studies of deposition patterns, especially

in the Coastal Plains of North Carolina. 

Several aspects of the research program are already under way. New data on emissions of

ammonia from waste lagoons and animal barns/houses have been gathered and are under review. Studies

of deposition, deposition velocities, and movements of ammonia in the environment have begun, and a

nitrogen balance is being developed to better understand sources, sinks, and exchanges of nitrogen

compounds. Emissions data for ammonia and NOx sources have been produced. Modeling using the

Regional Atmospheric Deposition Model (RADM) and Models-3 is under way. A general conference on

ammonia and other atmospheric nitrogen compounds was held in June 1999, in addition to intensive

reviews of the North Carolina research program as individual studies are completed. These analyses will

contribute to an understanding of which sources or source categories are generating the most

environmental impact and which should be the focus of additional management efforts (Personal

Communication with George Murray, NC DENR, September 9, 1998).

Maryland’s Power Plant Research Program

The Maryland Department of Natural Resources (DNR), Power Plant Research Program, in

cooperation with other partners, has several projects ongoing in the Chesapeake Bay watershed. These

include applying the CALPUFF model to develop estimates of Maryland’s contribution of atmospheric

deposition of nitrogen to the Chesapeake Bay; using CALPUFF to assess the implications of possible

utility emissions trading under title I of the CAA and impacts of deregulation on power plant emissions. 

The DNR also supports studies on air toxics, particularly mercury from coal-fired power plants, the

migration of metals and nitrate through watersheds (including coastal wetlands and forests), and

economic resource valuations associated with implementation of the CAA. 

Florida’s Mercury Rule: Progress in Reducing Atmospheric Mercury

Emissions

The amount of mercury in Florida’s municipal solid waste stream has been dropping rapidly due

to the implementation of statutes and rules designed to reduce or replace mercury in the manufacture of

widely used products, recycle mercury-containing items such as fluorescent lamps, and control mercury

at the point of release. One tool the Florida Department of Environmental Protection uses to reduce

atmospheric mercury emissions is a rule (i.e., “The Mercury Rule”) adopted in 1993 that limits mercury

emissions from municipal waste combustors (MWCs) to a level that is more stringent than the applicable

EPA standard. Florida’s strict mercury emissions standard is currently being met by over half of the

MWCs in the State, and all MWCs in the State are expected to meet the standard in the year 2000. The

rule also requires that every MWC unit perform a mercury stack test at least once each year. With over 5

years of test data available, it is clear that the uncontrolled (i.e., no up-front sorting of waste and no fine
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-53

Participants in the South Florida Mercury Program

C Florida Department of Environmental Protection 

C Florida Game and Fresh Water Fish Commission 

C South Florida Water Management District

C U.S. EPA

C U.S. Geological Survey

C National Park Service

C U.S. Fish and Wildlife Service

C U.S. Army Corps of Engineers

C Florida Electric Power Coordinating Group

C Electric Power Research Institute

C Florida Power & Light Company

C Florida International University

C Florida State University

C University of Florida

particulate control) MWC units in Florida are emitting about 65 percent less mercury than just 5 years

ago. With post-combustion controls (e.g., carbon injection) designed to capture mercury, the stack

emission rates at some Florida MWCs have been reduced an additional 80 percent. In 1997, the average

mercury emission rate for south Florida MWC units was 31 μg/dry standard m3 at 7 percent oxygen

(Memorandum from Michael M. Hewett to Howard L. Rhodes, August 26, 1998).

South Florida Mercury Science Program

Mercury bioaccumulation in wildlife

is extensive in Florida (FDEP 1996). High

levels of mercury in several species of fish

have resulted in bans or restrictions on their

consumption in over half of the fresh waters of

the State. The entire Florida Everglades is

covered by fish consumption bans. In

addition, the mercury problem places at risk a

variety of wildlife within the Everglades, most

notably top predators such as the endangered

Florida Panther. The contribution of

atmospheric deposition of mercury to this

regional environmental problem is a subject of

several current research efforts.

The South Florida Mercury Science

Program is a broad, multidisciplinary effort by scientists from State and Federal agencies, State

universities, industry groups, and others (see sidebar) working together to understand and address

mercury bioaccumulation in South Florida (FDEP 1996). The program is designed to determine the

following:

• Potential risks to humans and wildlife from mercury in South Florida;

• How mercury enters the aquatic food chain and concentrates in predators;

• Chemical and biological pathways for transformation of inorganic mercury into methylmercury;

• The origin of mercury in South Florida’s atmosphere and waters;

• How mercury moves through air, water, and soil; and,

• Actions that could be taken to reduce levels of mercury in fish and wildlife.

The Florida Everglades is currently the focus of the most in-depth and comprehensive research

on mercury in the environment. Scientific findings in the areas of atmospheric mercury deposition,

aquatic chemistry and cycling of mercury, and bioaccumulation of mercury in food chains have broad

application to many of the Great Waters (see Chapter II for information on mercury in the Great Waters). 

In addition, scientists studying mercury in South Florida hope to incorporate their findings into a model

that could be applied to other ecosystems. 
Chapter III

Major Programs and Activities

Page III-54 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Studies to date identified the atmosphere as the primary source (>95 percent) of mercury

impinging on the Everglades. Much remains to be learned, however, about the sources of mercury as

well as its fate in the environment. Several of the key projects currently under way are described below.

Florida Atmospheric Mercury Study (FAMS)

The FAMS was a large, regional-scale study conducted from 1992-1996 and designed to measure

long-term temporal and spatial trends in atmospheric mercury transport and deposition in Florida. While

most of the sites were remote, some were extremely close to or in urban areas (e.g., the Fort Meyers site). 

Data were collected over a 3-year period at nine sites (seven in South Florida), including monthly

integrated samples of mercury in rainfall and weekly integrated vapor phase and particulate phase

mercury samples. Preliminary analysis of the FAMS data indicated the following:

• More than 90 percent of the mercury found in the Everglades was from atmospheric deposition,

while less than 10 percent was from agricultural runoff;

• Wet deposition of mercury to South Florida was high – approximately double what has been

observed at other North American remote sites;

• Particulate mercury levels were relatively low;

• Mercury deposition exhibited a strong seasonal trend – 85 percent of annual deposition occurs in

the summer; and,

• Slight spatial trends were evident in South Florida.

Although the FAMS study design limited its ability to differentiate between local, regional, and

global sources of atmospheric mercury, the researchers conducting the study suggested that local source

contributions of mercury to the Everglades are less dominant (<30 percent) than regional and/or global

contributions (Guentzel et al. 1995).

South Florida Atmospheric Mercury Monitoring Pilot Study (SoFAMMS)

The SoFAMMS was a short-term, very intensive pilot study focused on determining the ability of

state-of-the-art sampling, measurement, and modeling techniques to track mercury from sources to

receptors. As a complement to FAMS, SoFAMMS was carried out to assess the influence of local

mercury sources in the developed Southeast Florida Coast on the atmospheric deposition of mercury to

the Everglades. Over a 1-month period (August 6, 1995 - September 6, 1995), SoFAMMS measured

mercury emissions from three source types (municipal waste incinerator, medical waste incinerator, and

coal-fired cement plant), meteorological conditions across the study area (surface and upper air), and

several forms of atmospheric mercury and deposition at 17 ambient monitoring sites. The data were

subjected to extensive dispersion, receptor, elemental composition, and meteorological modeling. The

study found a wide range in spatial variability of mercury wet deposition. Volume weighted mean

concentrations ranged from 13 to 31 ng/l across the 17 sites. The highest mercury concentrations were

observed in the urban areas (19-31 ng/l). The sites in the Everglades were lower but still elevated,

ranging from 13-20 ng/l. Those precipitation events in the Everglades with high mercury concentrations

were also found to contain elevated concentrations of other trace element species known to be tracers for

anthropogenic sources. The precipitation data were subjected to extensive meteorological, atmospheric

dispersion, and source apportionment modeling. The results of the modeling indicated that greater than

70 percent of the mercury wet deposited to the Everglades were accounted for by waste incineration and
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-55

oil combustion sources, contrary to the preliminary FAMS results that indicated that local sources

contribute less than 30 percent (Dvonch et al. 1998). Furthermore, monitoring data from these three

sources were the first data to indicate that a high percentage of emissions from incinerators are in the

form of divalent (reactive) mercury. Based on these results, EPA’s Office of Research and Development 

has begun methods development efforts for ambient and source mercury speciation techniques. 

Mercury Cycling in the Florida Everglades Project

The overall objective of this project is to provide resource managers scientific information on the

hydrological, biological, and geochemical processes controlling mercury cycling in the Everglades

(Krabbenhoft 1996). Specific areas of research include geochemical studies of mercury, mercury

methylation and demethylation studies, interactions between dissolved organic carbon and mercury,

mercury accumulation in sediments, physical and chemical processes in peat, sulfur cycling studies,

biological uptake of mercury and lower food chain transfer pathways, and groundwater/surface water

exchange. The USGS is leading this research effort, and participating scientists are from USGS,

SFWMD, FDEP, EPA, Wisconsin Department of Natural Resources, and University of WisconsinMadison. 

South Florida Ecosystem Assessment Project

This project is part of the EPA Region IV Regional Environmental Monitoring and Assessment

Program (R-EMAP), which was designed to monitor the condition of ecological resources in South

Florida (Stober et al. 1996). The project was intended to address several issues that threaten the

Everglades ecosystem, including mercury contamination. 

The project assessed mercury concentrations (e.g., in water, soil, algae, mosquitofish) at

approximately 700 sampling sites. Interim findings provide an indication of the spatial distribution of

mercury within the Florida Everglades as well as the levels of mercury contamination at various trophic

levels in the food chain (Stober et al. 1996). The spatial distribution of mercury within the Everglades is

relevant to the Great Waters research because it helps define the environmental conditions under which

methylation and bioaccumulation occur. For example, the highest concentrations of methylmercury were

found in fish, birds, and algae from the marsh sites between Alligator Alley and Tamiami Trail. North of

Alligator Alley, the organic compounds and reduced sulfate are believed to bind the mercury and

methylmercury so it is not available for uptake by organisms. South of Tamiami Trail, lower

concentrations of sulfate and total phosphorous probably limit microbial methylation and organic

production rates, respectively. In addition, researchers have found methylating bacteria associated with

periphyton (attached algae) mats, which are more common in the marsh sites between Alligator Alley and

Tamiami Trail.

Additional sampling has been conducted, and an updated report is expected soon. The study

results will be used to answer the seven questions identified for mercury. The EPA Region IV is also

studying the complex interactions between mercury contamination and other issues, such as

eutrophication, habitat alteration, and hydropattern modification.

Midwestern Pollution Prevention Activities

Since the Second Great Waters Report to Congress, State and local pollution prevention

activities have helped to reduce releases of Great Waters pollutants of concern. Six such activities in the

Midwest are described below.
Chapter III

Major Programs and Activities

Page III-56 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

State Pesticide Clean Sweep Programs

Over time, unwanted pesticides have accumulated in the barns, sheds, and storage areas of

farmers, ranchers, golf courses, pest control operators, and other pesticide users. The pesticides may be

unwanted for a variety of reasons – the products could be banned, unusable, or not needed. Farmers and

other small businesses may have difficulty determining how to properly manage these pesticides since

some (but not all) may be hazardous wastes when they are disposed.

States have addressed the problem of accumulated unwanted pesticides by establishing waste

pesticide collection and disposal programs, commonly called “Clean Sweeps.” These programs provide a

simple way to properly dispose of unwanted pesticides at little or no cost to the participants. Because

each State has designed its program to fit its own needs and funding sources, there is no single “typical”

Clean Sweep program. Some of the variations include the following:

• Format – The pesticides may be collected by holding single-day collection events, picking up

pesticides from individual farms, or establishing permanent collection sites; 

• Type of waste collected – Waste pesticide collections may be combined with household

hazardous waste programs either by consolidating all of the waste or by collecting both waste

types at a single site but handling them separately; 

• Organizer – The programs may be run by a State regulatory agency, the agricultural extension

service, a county, or a combination of these;

• Funding source – Clean Sweep programs may be funded through State pesticide registration

fees, State legislature appropriations, Federal grants, or fees assessed to participants; and, 

• Participants – Some programs are limited to farmers, while others are open to households and/or

small businesses.

State Clean Sweep programs have been extremely successful in removing pesticides from the

environment and ensuring the proper management of these materials. A few highlights of their

accomplishments through 1997 include the following:

• Clean Sweep programs have collected and disposed of more than 12 million pounds of

pesticides;

• Over 40 States have collected and disposed of some pesticides;

• About 20 States have had on-going Clean Sweep programs since 1995 (or earlier); and,

• The collections bring in an average of 200-300 pounds of pesticide per participant (where 100

pounds is equivalent to about 11 gallons of liquid pesticide).

In addition, Table III-7 presents the amounts of pesticides that have been collected nationwide based on

the limited data that have been collected. Despite this progress, efforts in this area need to continue. 

There is a large, but unquantified, amount of unused and/or unwanted pesticides that needs to be

collected.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-57

Table III-7

Pounds of Pesticides Collected through Clean Sweep Programs Nationwide

Pesticide Average Percent (per

collection)

Total Amount in

U.S. (pounds)

DDT 3.86 463,200

Toxaphene 2.98 357,600

Chlordane 1.46 175,200

Mercury 1.53 183,600

Dieldrin 0.48 57,600

Illinois Clean Sweep Partners for PCB and Mercury Wastes

The presence of mercury and PCBs in the environment is partially attributable to their

widespread use in commercial and consumer products, particularly electrical equipment. While newer

technologies in products, such as transformers, capacitors, thermostats, and switches, are PCB and

mercury free, older products are not and still pose potential health and environmental risks. Currently,

much of the PCB- and mercury-containing equipment encountered during maintenance, remodeling, and

demolition work is disposed of in the municipal solid waste stream. Because mercury and PCBs may be

released into the environment throughout the disposal process – from the point of disposal, the garbage

truck, a transfer station, and the solid waste landfill – the PCB and Mercury CleanSweep Partnership in

Cook County, Illinois is attempting to reduce the amount of PCB- and mercury-bearing equipment

entering the municipal solid waste stream.

The Cook County PCB and Mercury CleanSweep Partnership is a nonregulatory program

sponsored by public and private entities. The CleanSweep Partners have joined resources to help small

businesses and local governments identify and properly manage PCB- and mercury-containing materials

through a convenient and cost saving program. Through literature and training, the CleanSweep

Partners’ goal is to educate and assist small businesses and local agency field personnel in a voluntary,

public-private initiative to educate and motivate small business operators, particularly electrical and

demolition contractors, to manage and dispose of mercury- and PCB- bearing equipment in identifying,

handling, transporting, and disposing of mercury- and PCB-bearing equipment. For more information,

call the CleanSweep Partners hotline at 1-888-SWEEP22 or visit the web site at

www.erc.uic.edu/cleansweep.

The CleanSweep Partners are Commonwealth Edison, Electric Association, City of Chicago

Department of the Environment, Cook County Department of Environmental Control, Metropolitan

Water Reclamation District of Greater Chicago, Illinois Environmental Protection Agency, EPA, Clean

Harbors Environmental Services, National Oil Recyclers Association, Safety-Kleen Corp., North

Business - Industrial Council (NORBIC), and the University of Illinois at Chicago School of Public

Health.

Michigan Mercury Pollution Prevention Task Force 

The Michigan Mercury Pollution Prevention task force, which first convened in August 1994,

has been active in many mercury pollution prevention activities throughout Michigan. Significant

accomplishments include (1) a household hazardous waste collection program in 22 counties sponsored
Chapter III

Major Programs and Activities

Page III-58 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

by the Michigan Department of Environmental Quality (MDEQ), resulting in the collection of 200

pounds of mercury; (2) distribution of 16,000 copies of the “Merc Concern” brochure throughout

Michigan; (3) development of a mercury pollution prevention web page at http://www.deq.state.mi.us/

ead/p2sect/mercury; and, (4) distribution of mercury outreach materials to science teachers. Additional

accomplishments of the Michigan Mercury Pollution Prevention task force are described below.

• The Michigan Mercury Pollution Prevention task force worked with the automobile

manufacturers to phase out the use of mercury in automobiles, including identification of several

uses of mercury in automobiles (e.g., in switches, anti-lock brakes, active ride control devices). 

To date, the manufacturers have made great progress in eliminating mercury switches from

automobiles. 

• A cooperative effort initiated by the Detroit Wastewater and Sewage Department that included

the National Wildlife Federation, the Michigan Dental Association, and MDEQ collected

approximately 1,400 pounds of elemental mercury from 400 dentists at 11 drop-off sites.

• The MDEQ, Michigan Department of Agriculture, Michigan Farm Bureau, Michigan

Department of Community Health, Michigan Milk Producers Association, Independent

Cooperative Milk Producers, and Michigan State University collaborated on a dairy farm

mercury manometer pilot collection effort in two counties in Michigan. A total of 16 out of 18

manometers were replaced with a mercury-free substitute, and 12 pounds of mercury were

collected and properly disposed. This program may be expanded Statewide.

• Detroit Edison identified 1,500 pounds of mercury used in current product applications and

eliminated its use. Consumers Energy identified over 2,900 pounds of mercury used in product

applications in 1996 and is now replacing mercury-containing products with mercury-free

alternatives.

Indiana Statewide Mercury Awareness Program

The Indiana Statewide Mercury Awareness Program is a State and local partnership dedicated to

identifying commercial uses of mercury, investigating pollution prevention opportunities, and developing

and implementing outreach strategies. In October 1998, the Indiana Department of Environmental

Management initiated an effort to collect and recycle household items containing mercury. 

Minnesota Mercury Reduction Initiative

In 1997, the Minnesota Pollution Control Agency (MPCA) began the Mercury Contamination

Reduction Initiative, aimed at reducing mercury contamination in fish in Minnesota lakes. A major part

of this effort is to receive advice and comments from the public regarding the goals of the initiative. The

MPCA established a Mercury Advisory Council that includes representatives from government, business,

and environmental groups. 

The council’s charter is to devise a package of recommendations to reduce mercury

contamination in the environment. In January 1999, the council agreed to adopt a goal of reducing

mercury releases to Minnesota’s air and water by 70 percent (compared to 1990 levels) by 2005, to be

established in statute in the upcoming legislative session. 
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-59

The recommendations that the council voted to forward to the MPCA include the following:

• Encouragement of voluntary commitments on the part of sources of mercury emissions (e.g.,

power plants, taconite facilities, sewage sludge incinerators) to reduce or work toward reducing

mercury emissions;

• Development of a package of seven strategies that the State will advance at the national level to

encourage States and the Federal government to act in concert to reduce national mercury

emissions; and,

• Development of a package of strategies to persuade consumers to reduce their purchases and use

of mercury-containing products and encourage counties to collect more mercury-containing

waste in their household hazardous waste pickups.

Western Lake Superior Sanitary District (WLSSD) Pollution

Prevention Efforts

The WLSSD is the largest wastewater treatment facility that discharges to the Lake Superior

watershed. The WLSSD developed a multimedia mercury zero discharge pilot project with hospitals,

clinics, educational institutions, laboratories, and dental practices. As part of this effort, WLSSD

partnered with the Northeast District Dental Society to develop recycling procedures for materials

containing amalgam particles. In the first year of the project, over 500 pounds of waste material

containing amalgam was collected for recycling. Based on the results of the WLSSD pilot project,

WLSSD compiled the Blueprint for Mercury Elimination, which is a document designed for use by other

wastewater treatment facilities in developing and implementing mercury reduction programs. 

Northeast States and Eastern Canadian Provinces Mercury Study

During 1996 and 1997, the Northeast States (i.e., Connecticut, Maine, Massachusetts, New

Hampshire, New Jersey, New York, Rhode Island, Vermont) and Canadian Eastern Provinces (i.e., New

Brunswick, Newfoundland and Labrador, Nova Scotia, Prince Edward Island, and Quebec) held a series

of meetings and workshops to address shared mercury pollution issues. In June 1997, the New England

Governors and Premiers of Eastern Canada subsequently signed a Mercury Resolution that called for

cooperative efforts including the completion of the Northeast Mercury Study. The study, which was

completed in February 1998, reflects the combined contribution of State and provincial air, waste, and

water management agencies throughout the northeastern U.S. and eastern Canada. It is an informational

resource and serves as the foundation for future regional activities, including the development of a

coordinated action plan (see below) to reduce the environmental and public health impacts of mercury

pollution.

The study reports on emission inventories, transport and deposition modeling, multimedia

monitoring and assessment, communication (public and political outreach), and control strategies and

effectiveness of controls. The report recommends (1) identifying mercury as a hazardous air contaminant

under State air regulations to achieve the most stringent emission rate; (2) conducting an emissions

inventory of airborne sources of mercury; (3) implementing the Federal standards for municipal waste

combustors and medical waste incinerators by the year 2000; and, (4) forming in-State task forces to

assess, evaluate, and communicate mercury-related public health and environmental information. 
Chapter III

Major Programs and Activities

Page III-60 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Northeast Mercury Action Plan

In June 1997, the Conference of New England Governors and Eastern Canadian Premiers

charged its Committee on the Environment with developing a regional Mercury Action Plan. The plan

was released in May 1998 with the endorsement of the New England Governors and Eastern Canadian

Premiers. The Mercury Action Plan identifies steps to address those aspects of the mercury problem in

the Northeast that are within the control or influence of the region. The ultimate goal of the plan is the

virtual elimination of anthropogenic mercury releases in the northeastern U.S. and eastern Canadian

Provinces. In all, the plan lays out 45 specific recommendations addressing the following: 

C The establishment of a Regional Mercury Task Force to coordinate the implementation of the

plan;

C Mercury emission reduction targets for identified sources such as municipal solid waste

combustors, medical waste incinerators, sludge incinerators, utility and non-utility boilers, and

industrial and area sources;

C Source reduction and safe waste management practices, including recycling;

C Outreach and education, especially for high-risk populations; 

C Research, analysis, and strategic monitoring to further identify and quantify sources of mercury

deposition and to monitor deposition patterns and develop meaningful environmental indicators

to measure and track progress; and,

C Mercury stockpile management.

TRIBAL ACTIVITIES

Deposition of toxic air pollutants to the Great Waters adversely affects resources (e.g., fisheries)

that are of particular cultural and economic importance to many Native American tribes. This section

describes partnerships between tribal, State, and Federal governments that have enabled tribes to better

assess the ecological and human health risks posed by exposure to the Great Waters pollutants of

concern. Financial and/or technological support from Federal and State sources (through projects such as

the Effects on Aboriginals from the Great Lakes Environment (EAGLE), the Baseline Assessment

Project, and the American Indian Lands Environmental Support Project) and programs initiated by tribal

governments (such as aquaculture, CWA section 106 programs, or educational programs) are enabling

tribes to successfully conduct better quality assessments of their environment.

Effects on Aboriginals from the Great Lakes Environment (EAGLE)

The EAGLE, a partnership between the Assembly of First Nations and the Medical Services

Branch of Health Canada, is a community-based epidemiological project to research health effects of

environmental contaminants potentially affecting approximately 100,000 people in 63 First Nation

communities in the Great Lakes basin. The EAGLE’s main activities to date include (1) a survey of fish

and wild meat consumption in Great Lakes First Nations communities, (2) a program to establish safe

fish consumption guidelines for First Nations communities, and (3) a health survey accompanied by

blood and tissue sampling. Recognizing that even the perception of contamination can have a

tremendous impact on the relationship that First Nation communities have with the land, studies to assess
Chapter III

Major Programs and Activities

13 Personal Communication with Ed Liu, EPA. October 26, 1998.

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-61

Draft Baseline Assessment 

Priority Data Sets

8 Ambient air monitoring

8 Air toxics

8 Point and non-point source loadings

8 Fish consumption advisories

8 Ecological status of wetlands

8 Contaminated sediment

8 Pesticide use

8 Blood lead screening

8 PCB ballast in buildings

the socio-cultural impact of environmental contamination are also being conducted. Future activities for

the EAGLE project will focus on communication/outreach strategies and helping communities develop

environmental plans.

Baseline Assessment Project

The EPA initiated a Baseline Assessment of

Indian Country in order to provide easy-to-use and

accessible environmental data to assist tribal governments

and EPA in making sound environmental decisions. A

work group, led by the American Indian Environmental

Office (AIEO), is gathering and analyzing the existing

information on environmental conditions in Indian

country. In addition, EPA’s program offices have

identified 37 priority data sets that need to be developed

to track environmental management activities (see sidebar

for priority data sets relevant to the Great Waters

program). Next, EPA will develop a data management

system to meet the data needs. In addition, EPA’s Office of Water is reassessing the 2,200 hydrologic

unit basins of the U.S. so that tribal lands can be geographically located within specific watersheds.13

Therefore, environmental conditions on tribal lands, as evaluated through the baseline assessment, will

be comparable to conditions on non-tribal lands within the same watersheds.

American Indian Lands Environmental Support Project

Established by EPA’s Office of Enforcement and Compliance Assurance, the American Indian

Lands Environmental Support Project (AILESP) is designed to assess the impact of toxic chemicals from

permitted point sources on tribal lands. The AILESP integrates release data for multiple sources and

media, and information on the potential impact of a variety of contaminants with compliance histories of

facilities within 3.1 miles of tribal lands. The information is assembled into a geographic information

system (GIS) to help users understand the sources and impacts of pollutants on tribal lands. Preliminary

AILESP data include release of trace metals (including cadmium, lead, and mercury) and nitrogen

compounds (including nitrogen dioxide, ammonia, nitrate, and NOx) from certain facilities.

Aquaculture

Interest in aquaculture in tribal communities has recently been stimulated by the desire to

preserve ancestral traditions while avoiding health risks associated with the consumption of contaminated

fish. Aquaculture is based on the premise that uncontaminated fish can be obtained by breeding and

rearing them at uncontaminated sites (e.g., isolating them from contaminated sediments) and feeding

them high-quality commercially-supplied food (i.e., circumventing the contaminated food chain). 

Buttner (1997) aided aquaculture efforts by three tribal communities: Akwesasne Mohawks (St. Regis

Mohawks), Mohawks of the Bay of Quinte, and Ojibway of Sucker Creek. Although the programs had

varying degrees of success, it was clear that aquaculture had the potential for producing “clean” fish,

while creating jobs and minimally impacting the environment.
Chapter III

Major Programs and Activities

Page III-62 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Tribal Air Quality Programs

In 1998, EPA issued a rule that authorizes tribes to develop air quality programs under the CAA. 

The EPA has also increased its financial support and technical assistance to tribes that choose to adopt

air quality programs. Numerous tribes have begun to develop these programs, including programs for

collecting air quality monitoring data and programs that address toxic pollutants that are generated in

Indian country. The EPA will regulate larger sources of air pollution in Indian country until tribes

develop their own regulatory programs. The EPA is also updating data on the number, type, and location

of sources of toxic pollutants that are located in Indian country. 
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-63 The Chlorine Institute

III.D INDUSTRY ACTIVITIES

A number of industry activities currently contribute to reduced emissions of Great Waters

pollutants of concern. These industry activities were developed by cooperative partnerships involving

industry groups, EPA, and other agencies. Some of the activities are noted under other sections of this

chapter, such as under the Michigan Mercury Pollution Prevention Task Force. The EPA has found that

nonregulatory partnerships can be an effective means of achieving or surpassing environmental goals. In

addition, industry is phasing out the use of some Great Waters pollutants of concern in the manufacture

of certain products. For example, the amount of mercury used for the manufacture of electric switches

and thermostats has been decreasing because of the shift to solid state devices and other alternatives (see

Volume II of EPA’s 1997 Mercury Study Report to Congress (U.S. EPA 1997e)).

CHLOR-ALKALI INDUSTRY MERCURY REDUCTION GOAL

In July 1997, the Chlorine Institute, on behalf of its members, committed to reduce mercury use

in the chlor-alkali industry by 50 percent to help the U.S. achieve the mercury reduction goals of the

Binational Toxics Strategy (see page III-66). The baseline average annual mercury usage by mercury cell

chlor-alkali plants for the 1990-1995 period was 160 tons per year. The industry’s goal is to reduce

mercury usage to 80 tons per year by 2005. In addition, as part of the agreement, the Chlorine Institute

will submit an annual progress report to EPA. The first annual report was submitted to EPA in May

1998. 

To ensure that appropriate oversight is provided for monitoring the progress in achieving the

commitment, the Chlorine Institute’s Board of Directors established ad hoc committees for technical and

management issues. All chlor-alkali producers using mercury cell technology are represented on both

committees. In addition, seven technical task groups were formed to address specific issues such as

identification of new mercury reduction control techniques and preparation of guidance documents to

assist industry members in achieving mercury reduction goals. 
Chapter III

Major Programs and Activities

Page III-64 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Hospitals Produce Mercury Wastes

“Medical waste incinerators are the fourth largest

releasers of mercury to the environment, constituting

approximately 10 percent of all emissions sources,

and hospitals are responsible for producing 1 percent

of the total municipal solid waste in the entire

country.” (U.S. EPA 1998d)

VOLUNTARY MERCURY AGREEMENT WITH NORTHWEST

INDIANA STEEL MILLS

On September 25, 1998, the Lake Michigan Forum, the Indiana Department of Environmental

Management (IDEM), and EPA signed a voluntary agreement with three northwest Indiana steel mills,

including Bethlehem Steel Burns Harbor, Ispat Inland Inc. Indiana Harbor Works, and U.S. Steel Gary

Works. The mills agreed to inventory mercury in equipment, materials, storage, and waste streams, and

to develop facility-specific plans for mercury pollution prevention. The companies signed the agreement

as part of the Lake Michigan Primary Metals Project, which is a pollution prevention effort initiated by

the Lake Michigan Forum. The Lake Michigan Forum is a stakeholder group that provides input to EPA

on the Lake Michigan Lakewide Management Plan and includes representatives from academia,

business, environmental and sportfishing groups, and local governments.

The agreement will result in facility-specific reduction plans outlining pollution prevention

activities through equipment substitutions, purchasing practices, recycling, better management, and

employee education. The EPA (including the Mercury Work Group of the Binational Toxics Strategy)

and IDEM will provide the companies with information on typical mercury sources, substitutions for

mercury in equipment, and recycling options. Both agencies and the Lake Michigan Forum will receive

progress reports from the mills. The reports will also be available to the public. The forum will promote

the initiative and its results throughout the Lake Michigan basin. This effort could serve as a model for

other companies and industries that use mercury-containing devices. 

AMERICAN HOSPITAL ASSOCIATION MOU

On June 24, 1998, the American Hospital

Association (AHA), which consists primarily of

health care provider organizations, established a

Memorandum of Understanding (MOU) with

EPA’s Office of Prevention, Pesticides, and

Toxics and EPA Region V. The MOU is intended

to provide AHA members with enhanced tools for

minimizing the production of pollutants and

reducing the volume of waste generated. The

information should also reduce the waste disposal

costs incurred by the health care industry.

The MOU outlined multiple primary goals and activities designed to aid in the exchange of

information between EPA and the health care industry. Highlights include the following:

C Development of a Mercury Waste Virtual Elimination Plan to eliminate mercury-containing

waste from the health care industry waste stream by the year 2005;

C Development of a Total Waste Volume Reduction Plan to reduce the volume of waste generated

by the health care industry by 33 percent by 2003 and by 50 percent by the year 2010; and,

C Investigation of pollution prevention opportunities with respect to ethylene oxide and other

persistent, bioaccumulative, and toxic pollutants.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-65

Businesses for the Bay

Since its launching by the Chesapeake Executive Council in 1996, more than 230 businesses have joined the

Businesses for the Bay. This includes not only private industries, but State and local government facilities as

well. Under this voluntary program, businesses commit to pollution prevention activities and goals. In 1998,

member facilities voluntarily reported that they had reduced or recycled 222 million pounds of waste. Of these,

13 facilities reported a resulting cost savings of $1.4 million, and 15 of the facilities offered pollution prevention

training to 6,300 employees. Businesses have also volunteered more than 70 of their technical experts to act

as mentors to offer pollution prevention advice to other companies on an as-needed basis. In 1998,

Businesses for the Bay received 2 national awards from the National Pollution Prevention Roundtable and the

National Environmental Education and Training Foundation for its successes as a model program.

This MOU specifically supports the goals and objectives of the PBT Initiative, the Mercury

Action Plan, and the Waste Minimization National Plan, and is also expected to help reduce atmospheric

deposition of mercury and other persistent toxic pollutants to the Great Waters (U.S. EPA 1998d).

ELECTRIC POWER RESEARCH INSTITUTE STUDIES

The Electric Power Research Institute (EPRI) has a broad-based research program which

conducts a large amount of research cooperatively with Federal and State agencies. Research sponsored

by EPRI on air toxics and nitrogen is the largest privately-funded program in the U.S. Current air toxics

studies focus on mercury, nickel, dioxins, and arsenic. These studies include atmospheric global,

regional, and plume modeling of mercury; measurement of natural mercury fluxes; historic patterns of

mercury deposition (sediment and peat cores); environmental effects and mercury cycling in lakes;

human health effects of mercury exposure; and, mercury and multimedia risk assessment. Research

characterizing emissions of air toxics has, and is, leading to better emission inventories relevant to a

number of air quality issues. The EPRI also conducts or sponsors research in atmospheric chemistry and

physics, including atmospheric modeling and measurement of PM, ozone, and their precursors (including

nitrogen species). On-going nitrogen research of specific interest to the Great Waters includes a small

study on measurement of organic nitrogen in precipitation near the Chesapeake Bay; development of a

nutrient model for the Chesapeake Bay airshed, watershed, and bay; a study on the feasibility of using

isotopic composition of ammonium in wet deposition for source attribution; and, research on the effects

of nitrogen speciation in atmospheric deposition on phytoplankton community composition and

productivity. In addition, EPRI is a contributor to a study with substantial funding from EPA and NOAA

that is being carried out by the Ocean Studies Board and Water Science and Technology Board of the

National Research Council’s Commission on Geosciences, Environment, and Resources to assess

eutrophication, coastal processes, and watershed management. The study report, due in spring 2000, will

review existing knowledge and make recommendations for action and research to reduce eutrophication

in coastal ecosystems through more effective watershed management. 
Chapter III

Major Programs and Activities

Page III-66 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

III.E WORK WITH OTHER COUNTRIES

The U.S. works with other nations on many issues concerning shared resources (e.g., the Great

Lakes) and transboundary environmental problems. A number of international activities concern the

Great Waters and Great Waters pollutants of concern. International activities relevant to air deposition

of pollutants to the Great Waters are discussed below.

CANADA - U.S. BINATIONAL TOXICS STRATEGY

On April 7, 1997, the U.S. and Canada signed the Great Lakes Binational Toxics Strategy (BNS). 

The BNS sets forth a collaborative process by which Canada and the U.S. will work toward the goal of

virtual elimination of persistent toxic substances resulting from human activity from the Great Lakes

basin, in order to protect and ensure the health and integrity of the Great Lakes ecosystem. The goal of

virtual elimination will be achieved through a variety of programs and actions that encourage cooperation

among all relevant sectors of society and which place primary emphasis on pollution prevention.

This coordinated strategy provides the framework to achieve quantifiable goals in a specified

timeframe. As noted in the discussion of the PBT Initiative (see page III-4), there are 12 Level I

pollutants that represent an immediate priority and are targeted for reduction and eventual elimination

through pollution prevention and other incentive-based actions. Nine of these 12 pollutants are Great

Waters pollutants of concern.
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-67

BNS Pesticides in the Great Lakes

In December 1998, EPA’s Great Lakes National

Program Office (GLNPO) released a draft report

entitled, Draft Pesticides Report in Response to the

Great Lakes Binational Toxics Strategy. A final

report will be released in fall 1999. The report

presents and analyzes data on the environmental

presence of five banned pesticides (i.e., chlordane,

aldrin/dieldrin, DDT, mirex, toxaphene) in the Great

Lakes, along with probable and suspected sources. 

The report fulfills a “challenge” created by the

Binational Toxics Strategy for EPA to confirm by

1998 the elimination of uses and releases of the

pesticides from sources that enter the Great Lakes.

The report concludes that although environmental

concentrations of the pesticides in the Great Lakes

basin have gradually declined for 20 years, they

remain at levels of concern in water, sediment, and

fish. The EPA found no evidence of environmentallysignificant, purposeful releases of the pesticides in

the U.S. and concluded that continuing inputs to the

Great Lakes are likely to originate from remaining

stockpiles of the pesticides held by consumers, longrange transport from countries where the pesticides

are not banned, and releases of the pesticides from

reservoir sources (e.g., contaminated sites). Based

on these findings, EPA concluded that there is a

continuing need to pursue activities set forth under

the Binational Toxics Strategy.

Both the U.S. and Canada have set

“challenge” goals to achieve reductions in

releases of the targeted pollutants. One of these

challenges is the commitment of both countries to

work together to assess atmospheric inputs of

persistent toxic substances to the Great Lakes

with the goal of evaluating and reporting jointly

on the contribution and significance of long-range

transport of these substances from worldwide

sources. In addition, Environment Canada will

complete inventories of ten selected air pollution

sources to support assessment of environmental

impacts of air toxics by 1999 and will

demonstrate alternative processes to reduce

emissions from five predominant sources by

2001. The BNS includes several specific

reduction goals or challenges for the Level I

pollutants. For the U.S., these reductions will be

based on the most recent and appropriate

inventory for each pollutant (e.g., the mercury

inventory is based on 1990 levels). Canada plans

to use an inventory from 1988.

At the initial June 1997 BNS stakeholder

meeting, participants developed a plan to

implement the strategy, which applied the

following steps to address each priority substance

or category of substance: (1) information

gathering, (2) assessment of current regulations

and programs, (3) identification of cost effective options for further reductions, and (4) recommendations

and implementation of actions. 

Since the initial stakeholder meeting, substance-specific work groups have been established and

are gathering information about baseline levels and sources of pollutants, as well as current programs

affecting the pollutants. In addition, some work groups are attempting to identify cost-effective options

to achieve reductions. Specific highlights of the mercury work group activities include the AHA MOU

(see page III-64), work with the chlor-alkali industry (see page III-63), and an agreement with the steel

industry (see page III-64). The PCB work group has supported Clean Sweep programs (e.g., the Illinois

Clean Sweep Program described on page III-57) to reduce existing stockpiles. With the International

Joint Commission, the BNS participants developed a draft report on sources, pathways, and

transformations of the BNS compounds. This report, Identifying Source Regions of Selected Persistent

Toxic Substances in the U.S., identifies and ranks source regions for BNS pollutants, identifies regulatory

and voluntary programs to control emissions of these compounds, and determines the emissions

inventory and control gaps that exist for the BNS compounds. In addition, EPA’s Great Lakes National

Program Office released a Draft Pesticides Report in Response to the Great Lakes Binational Toxics

Strategy in December 1998 (see sidebar). Many additional activities that support the Binational Strategy

have been implemented by a wide variety of stakeholder groups and are outlined in the Draft Great Lakes

Binational Toxics Strategy: Activities by Partners (U.S. EPA and Environment Canada 1998). Table

III-8 describes the BNS challenge goals for the U.S. for each Level I substance and summarizes recent

activities with respect to those goals.
Chapter III

Major Programs and Activities

Page III-68 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Table III-8

U.S. BNS Challenge Goals and Activities for Level I Substances

Level I Substance U.S. Challenge Goal Progress/Activities

Mercury and

Compounds

By 2006, a 50 percent

reduction in deliberate use

and a 50 percent reduction in

release from human-activity

sources. This release

reduction applies to the

aggregate releases to the air

nationwide and to releases to

the water in the Great Lakes

basin.

BNS work group activities are focusing on voluntary

actions. Formal collaborative efforts are under way

with the chlor-alkali industry, the American Hospital

Association, and three Indiana steel mills. Outreach

projects are ongoing with manufacturers and users of

mercury relays and switches, utilities, and laboratories.

Dioxins and Furans By 2006, a 75 percent

reduction in total releases

from human-related activities. 

This release reduction applies

to the aggregate releases to

the air nationwide and to

releases to the water in the

Great Lakes basin.

The BNS dioxin work group is coordinating closely with

the PBT Initiative dioxin efforts, including a Great

Lakes State pilot to target air emissions using crossmedia authorities. Voluntary reduction efforts are also

planned.

PCBs By 2006, a 90 percent

reduction nationally of highlevel PCBs (>500 ppm) used

in electrical equipment. 

Ensure that all PCBs retired

from use are properly

managed and disposed of to

prevent accidental releases. 

The BNS PCB work group is developing a work plan. 

Voluntary actions are being pursued through

expanding EPA Region V’s PCB phasedown program,

encouraging national replication of the phasedown

program, implementing a clean sweep pilot in Chicago,

and encouraging a national PCB reduction effort.

Chlordane, DDT,

Aldrin/Dieldrin,

Mirex, Toxaphene,

Octachlorostyrene

Confirm, by 1998, that there is

no longer use or release from

sources that enter the Great

Lakes basin. If ongoing longrange sources from outside

the U.S. are confirmed, use

existing international

frameworks to reduce or

phase out releases.

A final BNS status report on use and release from

Great Lakes basin sources is due fall 1999. The BNS

work group is also developing a work plan. The EPA

will continue clean sweeps to reduce stockpiles in the

Great Lakes basin and will work with stakeholders and

Great Lakes States to reduce pesticide reliance. The

BNS octachlorostyrene work group is focusing on

defining sources, releases, and environmental loadings

(and, to some extent, toxicity and bioaccumulation).

Alkyl Lead Confirm no use in automotive

gasoline by 1998. Support

and encourage stakeholder

efforts to reduce alkyl lead

releases from other sources.

The EPA issued a “confirmation of no use in

automotive gasoline” report under the BNS in

December 1998, broaden stakeholder involvement,

encourage stakeholder minimization of use/release

from other sources (e.g., aviation, racing,) and track

efforts to develop unleaded alternatives for aviation

and racing fuel.

Hexachlorobenzene Seek, by 2006, reductions in

releases that are within or

may have potential to enter

the Great Lakes basin from

sources resulting from human

activity (percentage goal not

yet established).

An initial step under the BNS is to quantify loadings to

set a realistic percentage goal. The BNS work group

will consider approaches to reduce releases during

pesticide manufacturing and use, chlorinated solvent

manufacturing, and possibly aluminum manufacturing.
Chapter III

Major Programs and Activities

Level I Substance U.S. Challenge Goal Progress/Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-69

Benzo[a]pyrene Seek, by 2006, reductions in

releases that are within or

may have potential to enter

the Great Lakes basin from

sources resulting from human

activity (percentage goal not

yet established).

The BNS work group was developing a work plan in

1998.

INTERNATIONAL JOINT COMMISSION

Originally created in 1909 for the purpose of resolving disputes between the U.S. and Canada,

the International Joint Commission (IJC) is charged with the responsibility of evaluating and assessing

the progress of commitments made by Canada and the U.S. under the 1978 Great Lakes Water Quality

Agreement (GLWQA). In keeping with this responsibility, the IJC prepares a biennial report outlining

its findings and recommendations. These recommendations are based on information compiled from the

Great Lakes Water Quality Board (WQB), Science Advisory Board (SAB), International Air Quality

Advisory Board (IAQAB), Council of Great Lakes Research Managers, various task forces, and through

a variety of public consultation activities. In 1985, the WQB established a list of 11 critical pollutants

which remain the focus of IJC’s efforts today. Nine of the critical pollutants overlap with the Great

Waters pollutants of concern and the PBT Initiative: DDT/DDE, dieldrin, hexachlorobenzene, lead,

mercury, PCBs, dioxins and furans, and toxaphene.

The IJC’s Ninth Biennial Report on Great Lakes Water Quality, published in June 1998, focused

on the issue of persistent toxic substances in the Great Lakes ecosystem, which has been the major focus

of IJC’s biennial reports since 1990. The IJC continues to stress the importance of eliminating these

substances. As in previous biennial reports, IJC developed targeted recommendations to aid Canada and

the U.S. to achieve the objectives under the GLWQA. Historically, these recommendations have been

incorporated into existing or planned programs, and a few have achieved specific and direct results,

including The Great Lakes Binational Toxics Strategy. Recommendations to the U.S. and Canada from

the 1998 report include the following:

C Accelerate the development of integrated, binational programs to reduce and eliminate sources of

persistent toxic substances to the atmosphere;

C Develop and communicate a comprehensive strategy for reducing mercury and NOx emissions

associated with energy production and use;

C Expand research into endocrine disrupting chemicals in humans and wildlife;

C Support the development and application of ecosystem models;

C Identify, assess, and support surveillance and monitoring programs essential to track contaminant

loadings to, and concentration trends for, each of the Great Lakes; and,

C Focus reduction and elimination efforts on dioxins, furans, mercury, and PCBs.

The IJC presented additional recommendations on agricultural practices, communication of scientific

information, radioactivity, ecological economics, and contaminated sediment in areas of concern

(AOCs).
Chapter III

Major Programs and Activities

Page III-70 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE LRTAP

PROTOCOLS ON HEAVY METALS AND POPS

In 1979, members of the United Nations Economic Commission for Europe (UN-ECE) created

the Long-Range Transboundary Air Pollution (LRTAP) convention to provide a framework for

participating countries to limit, gradually reduce, and eventually prevent air pollution. Today, the 57

countries included in the UN-ECE region are the Russian Federation, the Newly Independent States,

Central and Eastern Europe, Western Europe, Canada, and the U.S. Protocols to the LRTAP convention

negotiated since its creation establish more specific and legally-binding controls and emission reduction

targets for certain air pollutants. 

In June 1998, the members of the UN-ECE signed protocols on persistent organic pollutants

(POPs) and heavy metals. The POPs are defined as organic substances that possess toxic characteristics,

are persistent, bioaccumulate, are prone to long-range transboundary transport and deposition, and are

likely to cause significant adverse human health and environmental effects. The POPs protocol bans the

production and use of eight compounds (i.e., aldrin, chlordane, dieldrin, endrin, hexabromobiphenyl,

kepone, mirex, and toxaphene) and limits the production and use of five compounds (i.e., DDT,

heptachlor, hexachlorobenzene, lindane, and PCBs). In addition, the POPs protocol requires countries to

apply best available technology methods to limit air emissions from stationary sources of dioxins, furans,

PAHs, and hexachlorobenzene. The protocol on heavy metals regulates cadmium, lead, and mercury. 

The protocol bans the use of lead in gasoline and the use of mercury in batteries and requires the

application of best available technology to limit air emissions from major stationary sources of all three

metals.

Both of these protocols to the LRTAP convention incorporate less stringent obligations for

countries with economies in transition, and the protocols offer alternative compliance options to allow

some parties to apply different control strategies, provided these strategies achieve equivalent emission

reductions. The protocols also commit participating parties to reduce total national air emissions to

below the levels reported for a reference year (between 1985 and 1995). 

Most recently, in December 1999, the U.S. and Canada, along with European members, signed

the LRTAP Protocol to Abate Acidification, Eutrophication and Ground-level Ozone. This Protocol is

the most sophisticated environmental agreement so far because its creates the first comprehensive,

multinational structure to simultaneously reduce the long range transport of the various pollutants that, in

different combinations, cause acid rain, smog and other serious air pollution problems. The signing of

this agreement also initiates a new phase within LRTAP to increase emphasis on implementation,

compliance, review and extension of existing protocols. In order to accommodate the domestic (acid

rain) and bilateral (ozone) processes which are currently under way in both countries, both Canada and

the United States will incorporate their emission reduction commitments for sulphur dioxide, nitrogen

oxides and volatile organic compounds into the Protocol at the time of its ratification. This

accommodates the timing of the bilateral initiative to complete negotiations in the year 2000 of an ozone

annex to the U.S. - Canada Air Quality Agreement (see below).

Further information on the LRTAP Convention and its Protocols can be found at

http://www.unece.org/env/lrtap. 
Chapter III

Major Programs and Activities

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page III-71

Recent Developments on the 

Mercury North American Regional Action Plan

In October 1998, the North American Implementation

Task Force on Mercury held a Science Experts

Workshop that focused on mercury source

identification, fate, transport, and monitoring and the

identification of research needs in these areas. The

workshop resulted in a Strategy for the Development

of a Trinational North American Mercury Baseline for

mercury concentrations and fluxes (Draft Agenda,

October 6-8, 1998, Science Experts Workshop on

Mercury, Las Vegas, NV).

UNITED NATIONS ENVIRONMENT PROGRAM GLOBAL POPS

INITIATIVE

At its 19th session in February 1997, the United Nations Environment Program (UNEP)

Governing Council concluded that international action, including a global, legally-binding instrument, is

needed to reduce the risks to human health and the environment arising from the release of 12 POPs:

aldrin, dieldrin, DDT, endrin, chlordane, hexachlorobenzene, mirex, toxaphene, heptachlor, PCBs,

dioxins, and furans. The Governing Council decided that immediate international action should be

initiated to reduce and/or eliminate the emissions and discharges of the 12 POPs, and, where appropriate,

eliminate production and subsequently the remaining uses of those POPs that are internationally

produced. Accordingly, the first session of the Intergovernmental Negotiating Committee (INC) for an

International Legally Binding Instrument for Implementing International Action on Certain Persistent

Organic Pollutants was held in Montreal in June 1998. The INC is expected to complete an

Internationally Legally Binding Instrument by the middle of the year 2000.

Currently, the INC is establishing an expert group for the development of science-based criteria

and a procedure for identifying additional POPs as candidates for future international action. In addition,

UNEP has initiated a number of immediate actions, such as studies to identify alternatives to POPs,

current PCB inventories, sources of dioxins and furans, and available POP destruction capacity.

NAFTA COMMISSION ON ENVIRONMENTAL COOPERATION

SOUND MANAGEMENT OF CHEMICALS PROGRAM

On January 1, 1994, the U.S., Canada, and Mexico officially established the North American

Agreement on Environmental Cooperation (NAAEC) to foster greater cooperation on environmental

issues, including the management and control of several Great Waters pollutants of concern. 

Subsequently, the NAAEC created the Commission on Environmental Cooperation (CEC) to address

regional environmental concerns, prevent potential trade and environmental conflicts, and promote

effective enforcement of environmental law. One of the CEC’s first activities was to develop a program

to identify, measure, and mitigate the environmental impacts of the North American Free Trade

Agreement (NAFTA) (NAAEC 1999).

In 1995, the CEC established a Sound

Management of Chemicals (SMOC) Work

group to address the issues of persistent toxic

substances and their effects in and transport

between the North American countries. The

original duties of the work group members

included the development of a North American

Regional Action Plan (NARAP) for the

management and control of PCBs (Commission

for Environmental Cooperation 1998). Since

1995, NARAPs have been developed for PCBs,

DDT, chlordane, and mercury. The CEC is

currently developing a Phase II NARAP for

mercury, which represents an amendment to

the first mercury NARAP. The CEC is developing NARAPs for dioxins and furans, and

hexachlorobenzene. Draft and final NARAPS and additional information related to this effort is

available at www.cec.org/programs_projects/pollutants_health/smoc/smoc-rap.cfm?varlan=english. 
Chapter III

Major Programs and Activities

Page III-72 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

U.S.-CANADA AIR QUALITY AGREEMENT

The U.S.-Canada Air Quality Agreement, which was signed in March 1991, addresses

transboundary air pollution between the two countries. The agreement focuses on acid rain and ozone

transport issues, prevention of deterioration of air quality and visibility, development of emissions

monitoring systems, notification and assessment of major projects which could affect transboundary air

quality, and coordinated research activities. The two countries established the Air Quality Committee

(AQC) to help implement the agreement. In the past, the AQC focused primarily on acid rain and

notification issues and is currently expanding the focus to address transboundary ground-level ozone and

fine particles (U.S. EPA 1998s). 

The agreement includes commitments by the U.S. and Canada to reduce SO2 and NOx emissions. 

Specifically, for NOx, the U.S. and Canada agreed to reduction goals amounting to about 10 percent of

the national NOx emissions for both countries by 2000. This is equal to approximately two million tons

in the U.S. and 100,000 tons in Canada. The U.S. expects to meet this goal through mobile and

stationary source NOx emission measures, a large part of which will be realized through Acid Rain

Program reductions of emissions from coal-fired electric power plants. After 2000, the U.S. expects to

achieve additional reductions in NOx from implementation of the ozone NAAQS and the NOx SIP call

(see page III-27). Canada has measures in place to reduce NOx emissions from stationary sources by

100,000 tons by 2000 through national emissions limits for new fossil-fueled power plants, retrofits at

several existing power plants, new source standards for boilers, process heaters, and cement kilns, and

reconstruction of a metals smelter. In addition, by 2010, Canada anticipates a 10 percent decline in NOx

emissions from 1990 levels as a result of improved emission standards for vehicles. 

In April 1997, the Canadian Minister of the Environment and the EPA Administrator reiterated

their commitment to addressing transboundary air pollution by signing a Joint Plan of Action for

Addressing Transboundary Air Pollution. The commitment focuses on the common concern of both

countries for ground-level ozone and fine particles and for protecting public health on both sides of the

U.S. - Canada border. Currently, the U.S. and Canada are negotiating an ozone annex to the U.S. -

Canada Air Quality Agreement which is expected to be completed by December 2000. This annex will

fulfill the two countries’ obligations under the LRTAP Protocol to Abate Acidification, Eutrophication

and Ground-level Ozone (see discussion above).
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-1 Steve Curcio, Pennsylvania Department of Environmental Resources

CHAPTER IV

SCIENCE AND TOOLS

In addition to the environmental progress discussed in Chapter II and the program progress

discussed in Chapter III, there has been significant advancement since the Second Great Waters Report to

Congress in the development and use of new scientific methods and tools needed to understand the

problem associated with Great Waters pollutants of concern. This includes improved understanding and

assessment capabilities in some areas and a clearer picture of remaining uncertainties and future research

needs in other areas. 

This chapter highlights recent advancements in scientific research, as well as new and improved

monitoring and modeling capabilities and databases that are improving our understanding of and abilities

to address public health and environmental risks posed by the pollutants of concern in the Great Waters. 

Unlike Chapter II, which focuses on the results of new research and monitoring for the purpose of

defining the overall problem, the discussion in this chapter focuses on developments and new findings

that improve our understanding of more narrow issues related to pollutant emissions, transport, loadings,

and effects. It also discusses the status and directions of research and information sources that will be

useful in future assessments of the Great Waters. Finally, the chapter identifies additional research and

tools that are necessary to address remaining uncertainties related to atmospheric deposition in the Great

Waters. This discussion is not intended to be comprehensive, but rather to highlight some of the key

scientific advancements since the Second Report to Congress. 
Chapter IV

Science and Tools

Page IV-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

WHAT MAJOR ADVANCEMENTS HAVE OCCURRED SINCE THE

SECOND REPORT?

This section summarizes a number of major advancements in scientific research, models, and

databases that are and will be useful in better understanding atmospheric deposition of the Great Waters

pollutants of concern. Recent developments in emissions inventories are presented first, followed by a

discussion of changes in programmatic direction and progress of several ambient air and deposition

monitoring networks and environmental monitoring networks. The last two main subsections provide a

discussion of recent scientific advancements in environmental fate and transport modeling, and exposure

and effects research and modeling. 

EMISSION INVENTORIES

National Toxics Inventory

Developing estimates of how much of a pollutant is being emitted is an important key to

characterizing the extent of the air toxics problem in the U.S., including persistent, bioaccumulative

toxics that are of concern to the Great Waters program. For about 20 years, EPA has routinely collected

emissions inventory data for criteria pollutants, such as lead, carbon monoxide, and particulate matter. 

For air toxics, however, scientists have had to rely on indirect estimates of emissions that are based on

emission factors and other imprecise methods. With the air toxics program in the CAA amendments of

1990 came a new focus on air toxics emissions inventories. This information can be used to estimate and

characterize risk and develop strategies to reduce risks from air toxics. These pollutants are emitted by

major, area, and mobile sources, and emission estimates from these sources can vary from the nationallevel to regional- and county-level estimates, and to facility- and process-specific emissions data that can

be used in air dispersion models. 

The dispersion and exposure modeling used to estimate and characterize risks from air toxics

requires a model-ready emissions inventory. As a result, EPA has compiled and continues to update and

refine the National Toxics Inventory (NTI). To date, EPA has compiled an inventory data set for the

1990 to 1993 period (called the 1993 NTI) and another for 1996. The 1993 NTI data, where available for

Great Waters pollutants of concern, are presented in Chapter II to characterize emissions and sources on

a national level. The NTI does not include emissions of air toxics from natural sources (e.g., plants,

volcanoes).

The 1996 NTI was completed in early 2000, but was not available in time to be included in this

report. It represents a substantial improvement over the 1993 NTI in that it is more complete in its

coverage of pollutants and their sources, and it carries a higher degree of spatial resolution owing to its

development from source-specific information (i.e., the “bottom-up” approach to inventory development)

and contains HAP emission estimates for major (facility-specific), area, and mobile on-road and non-road

sources. In these 1996 NTI efforts, a majority of the State and local air pollution control agencies have

provided direct emission information or a critical review of EPA-developed emissions in a coordinated

effort to develop the best inventory in the available timeframe. This approach provides estimates of

emissions at the county-level of resolution (or better, in many cases), which subsequently allows the

1996 NTI to be used to develop screening-level modeling assessments of ambient concentrations and

inhalation exposures down to the county-level. As such, the 1996 NTI represents the most recently

verified and complete emissions inventory available for national assessments. 
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-3

The EPA has been compiling the 1996 NTI using five primary sources of data: 

• State and local toxic air pollutant inventories (developed by State and local air pollution control

agencies);

• Existing databases related to EPA’s air toxics regulatory program;

• The EPA’s Toxic Release Inventory (TRI) database;

• Estimates developed using mobile source methodology (developed by EPA’s Office of

Transportation and Air Quality); and, 

• Emission estimates generated from emission factors and activity data. (NOTE: While major

sources were not estimated using emission factors and activity data, 30 area sources were in the

1996 NTI.)

Preference is given to State- and locally-generated information, where available. Where such

data are not available, existing data from EPA’s regulatory development databases are utilized. If neither

of these data sources contains information for a known stationary source, EPA uses data from the TRI.

The EPA also gives preference in inventory development to emissions data resulting from direct

measurements over those generated from emissions factors and activity data. 

The TRI database contains national inventory data submitted by individual facilities that meet

certain reporting criteria. The TRI does not account for smaller sources within a source category that do

not meet the reporting criteria. Although the TRI data are limited in source category coverage, in many

cases, TRI data are used because they are the only available means to estimate emissions from certain

source categories. For the missing States and for sources not included in the State inventories, MACT

data, or the TRI, EPA estimated air toxic emissions using air toxic emission factors and corresponding

activity data. 

The compilation of such a large data set presents a significant challenge to EPA and introduces

several limitations. In terms of consistency, the NTI is a composite of emissions estimates generated by

State and local regulatory agencies, industry, and EPA. Because the estimates originated from a variety

of sources and estimation methods, as well as for differing purposes, they vary in quality, included

pollutants, level of detail, and geographic coverage. Also, the accuracy of emissions estimation

techniques varies with pollutants and source categories. In some cases, an estimate may be based on few

(or only one) emissions measurements at a similar source. The techniques used and quality of the

estimates will vary between source categories (e.g., some have been better studied than others) and

between major, area, and mobile source sectors. Another limitation of the NTI is that emissions from

reservoir sources, such as volatilization from soils where chemicals were previously spilled or applied (in

the case of pesticides), are either missing or poorly quantified. If such sources are a major component of

the total emissions for a given chemical, NTI could under report total emissions for that chemical. 

Future updates of the NTI are scheduled every 3 years. However, similar to other inventories,

the NTI is dynamic and is subject to change (via periodic updates) as new, more reliable data become

available for the year it represents. Further, EPA continues to work with the State and local agencies to

promote consistency and accuracy in estimating and reporting emissions information for future years.
Chapter IV

Science and Tools

Page IV-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

The Great Lakes Regional Air Toxics Emissions Inventory

Under the auspices of the Great Lakes Commission, the eight U.S. Great Lakes States and the

Canadian province of Ontario have been engaged since the early 1990s in creating and updating a

regional air toxics emissions inventory of the Great Lakes pollutants of concern – the Great Lakes

Regional Air Toxics Emissions Inventory. The inventory covers 86 pollutants from point, area, and

mobile sources. The emissions estimates are at the process level, and the data are model-ready. The

inventory is compiled according to a regional protocol designed to provide data of consistent quality and

format throughout the Great Lakes region. The inventory data are supplied to the NTI; data for the 1993

reporting year were released in the summer of 1998. 

AMBIENT AIR AND DEPOSITION MONITORING NETWORKS

Figure IV-1 displays the monitoring sites for all ambient air and deposition monitoring networks

that measure Great Waters pollutants of concern in the regions of the Great Waters and throughout the

U.S. and parts of Canada. 

National Atmospheric Deposition Program/National Trends

Network

The National Atmospheric Deposition Program (NADP) began in 1978 as a cooperative program

between Federal and State agencies, universities, electrical utilities, and other industries to determine

geographical patterns and trends in wet deposition of sulfate, nitrate, hydrogen ion, ammonium, chloride,

calcium, magnesium, and potassium. The NADP was renamed as NADP/NTN (National Trends

Network) in the mid-1980s when the program had grown to almost 200 monitoring sites (Figure IV-1). 

The monitoring sites are located in rural areas, and data are collected on a weekly basis. The collected

data provide insight into natural background levels of pollutants. The network of NADP/NTN

monitoring sites allows for the development of concentration and wet deposition maps to describe the

trends and spatial patterns in the constituents of acid precipitation. The Mercury Deposition Network

(MDN), which is another component of the NADP, measures mercury levels in wet deposition at over 40

NADP sites (U.S. EPA 1998l). The data that are currently available from NADP/NTN and NADP/MDN

are presented in Chapter II to characterize the deposition of nitrogen and mercury, respectively.

Clean Air Status and Trends Network

The Clean Air Status and Trends Network (CASTNet) was initiated in 1987 to estimate dry

acidic deposition, to provide data on rural ozone levels, and to determine the effectiveness of national

emission control programs. The CASTNet is comprised of about 70 monitoring stations across the U.S.

(Figure IV-1). Data on atmospheric concentrations of sulfate, nitrate, ammonium, sulfur dioxide, and

nitric acid are collected weekly, and ambient ozone concentrations are collected hourly. Most of the

stations are operated by EPA’s Office of Air and Radiation; 19 stations are operated by the National Park

Service in cooperation with EPA (U.S. EPA 1998l). 
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-5

Figure IV-1

Monitoring Sites of Ambient Air and Deposition Monitoring Networks 

Measuring Pollutants of Concern

Does not display NADP/MDN mercury deposition monitoring site at St. Anicet in Canada.
Chapter IV

Science and Tools

Page IV-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Atmospheric Integrated Research Monitoring Network

Established in 1992, the Atmospheric Integrated Research Monitoring Network (AIRMoN),

which is sponsored by the NOAA Air Resources Laboratory, conducts research on both wet and dry

deposition based on measurements taken at a subset of NADP and CASTNet sites (Figure IV-1). The

primary AIRMoN objectives are determining the effectiveness of emission controls mandated by the

CAA, evaluating potential impacts of new sources of emissions on protected areas, and identifying

source/receptor relationships in atmospheric models. One notable distinction of the AIRMoN-wet

network is that sampling is conducted on a daily basis, whereas NADP/NTN data are collected on a

weekly basis. Daily sampling allows for the application of source-receptor models to individual storm

systems and reduces the storage artifact for ammonium. The AIRMoN-dry network has yielded direct

measurements of dry deposition that have been used to support inferred dry deposition measurements at

other NOAA and CASTNet stations. In the future, AIRMoN data will also be used to characterize spatial

variability around current deposition stations, which will improve NOAA’s ability to construct regional

deposition loadings estimates.

Integrated Atmospheric Deposition Network

The Integrated Atmospheric Deposition Network (IADN) is a joint U.S.-Canada program begun

in 1990 under a formal 6-year implementation plan. The IADN’s mandate, which is derived from Annex

15 of the Canada-U.S. Great Lakes Water Quality Agreement of 1987, is to determine atmospheric

loadings of toxic substances, including Great Waters pollutants of concern, to the Great Lakes and their

temporal and spatial trends. The IADN collects data that can be useful in assessing the relative

importance of atmospheric deposition. Under IADN, trends in pollutant concentrations in air and

precipitation are assessed and loading estimates of atmospheric deposition and volatilization of pollutants

are made every 2 years. The IADN network currently consists of one master station per Great Lake and

14 satellite stations (Figure IV-1). Stations are located in remote areas and do not assess urban sources

of pollution. The satellite stations do not meet the original siting criteria but are subject to quality

assurance and quality control requirements (U.S./Canada IADN Scientific Steering Committee 1998).

Detailed results from IADN are presented in Chapter II by pollutant group. General conclusions

include the following:

• Levels in air and precipitation appear stable for current-use pesticides such as endosulphan, but

levels for most other pesticides, PCBs, and lead are decreasing;

• Gas absorption appears to be the dominant deposition process for delivering semi-volatile

organic compounds (SVOCs), including PCBs and PAHs, to lake surfaces, while wet and dry

deposition dominate for the trace elements and higher molecular weight PAHs;

• For some IADN substances, like dieldrin and PCBs, the surface waters are behaving like a source

since the amount that is volatilizing from the water is greater than the amount being deposited to

the water;

• The lakes are sensitive to the atmospheric concentration of IADN chemicals, and this points out

the fragility of these resources given that long-range transport from other regions may be a

significant source of toxic pollutants; and,
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-7

• Air trajectory analyses indicate that many SVOCs are potentially originating from outside the

Great Lakes basin, whereas trace metals and PAHs may be associated with local sources

(U.S./Canada IADN Scientific Steering Committee 1998).

In 1998, the Second Implementation Plan for 1998 to 2004 was developed based on a review of

the program from 1990 to 1996. No major changes are anticipated under the Second Implementation

Plan. The IADN will continue surveillance and monitoring activities, related research, and provision of

information for intergovernmental commitments and agreements. Additional work to be completed under

the Second Implementation Plan is the development of a database for all U.S. and Canadian data. 

Potential modifications will be discussed in relation to the placement of satellite stations to assess urban

inputs and air-water gas exchange, criteria for changes to the IADN chemical list, coordination with other

research activities, quality assurance and control of IADN operations, and communication of IADN

results (U.S./Canada IADN Scientific Steering Committee 1998, U.S. EPA 1998m).

Chesapeake Bay Atmospheric Deposition Study

The Chesapeake Bay Atmospheric Deposition Study (CBADS) network was established by a

team of scientists from the University of Maryland, Virginia Institute of Marine Sciences, University of

Delaware, and Old Dominion University. In June 1990, CBADS began collecting data from three rural

(i.e., at least 50 km from urban areas) shoreline monitoring sites at Wye Institute and Elms Institute,

Maryland, and Haven Beach, VA. Measured parameters included wet and dry deposition and gas

exchange of elements (including lead and cadmium), individual PAHs, and total PCBs. Results of data

collected from June/July 1990 to the end of 1991 were reported in the 1994 Chesapeake Bay Basin

Toxics Loading and Release Inventory (1994 TLRI) (Chesapeake Bay Program 1994) and in the Second

Report to Congress (U.S. EPA 1997b). The 1994 TLRI results did not include any data on mercury or

current-use agrichemicals, nor did it provide information on wet deposition to urban areas in the

Chesapeake Bay watershed. An additional 21 months of CBADS wet deposition data were collected and

reported in the 1999 TLRI (making the total study period from June/July 1990-September 1993). This

new information on Great Waters pollutants of concern is presented in Chapter II by pollutant group.

Other atmospheric deposition studies were also reported in the 1999 TLRI, including data

collected for wet deposition and loadings of mercury and agrichemicals; however, only initial data were

available at the time of the report generation to estimate wet deposition loadings to urban areas. For the

1999 TLRI, urban wet deposition fluxes of metals, PAHs, PCBs, and mercury were assumed to be

enriched two-, four-, ten-, and two-fold over regional background levels, respectively. Analysis of

monitoring data collected by CBADS and other studies not included in the 1999 TLRI will be available

for the next report.

Air Toxics Monitoring

The EPA is currently developing a concept for an air toxics monitoring network and beginning

implementation. Ambient air toxics data would be useful to characterize ambient concentrations and

deposition in representative areas, to provide data to support and evaluate dispersion and deposition

models, and to establish trends and evaluate the effectiveness of strategies to reduce air toxics emissions. 

The goal is to build on monitoring already in place in State, local, and tribal programs as well as other

national networks. For example, in the near future, fine particulate matter speciation monitors will

provide ambient air measurements of several air toxic metals (including lead and cadmium compounds)

at over 50 urban locations in the country. Rural and remote monitoring of these metals takes place as

part of EPA’s efforts to assess regional haze. As the air toxics network is phased in, the pollutants to be

monitored are expected to include several of the compounds of concern to the Great Waters, such as
Chapter IV

Science and Tools

Page IV-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Condition of the Mid-Atlantic Estuaries

The EPA’s Office of Research and Development and

the Environmental Monitoring and Assessment

Program (EMAP) issued a report, The Condition of

the Mid-Atlantic Estuaries Report, that is the first in a

series of State-of-the-Region Reports for the MidAtlantic. The report discusses the adequacy of

current protective measures, the present condition of

natural resources, and the extent and possible

causes of ecological problems. These issues are

addressed through the evaluation of the best

available scientific information, including data from

large sampling programs throughout the estuaries,

and use of the latest scientific tools. Although the

Mid-Atlantic estuaries are being impacted by human

activities, active management by the States and EPA

has had positive results. Future State-of-the-Region

Reports for the Mid-Atlantic will address streams,

forests, and other resources (U.S. EPA 1998b).

mercury, POM, and metals. Information about the monitoring strategy can be found at

www.epa.gov/ttn/amtic/airtxfil.html.

The EPA has also begun a research effort for ambient air monitoring of dioxin and dioxin-like

compounds called the National Dioxin Air Monitoring Network (NDAMN). It is designed with several

objectives:

• To provide data useful for calibrating regional-scale, long-range transport models used in

estimating air concentrations of dioxin as a function of dioxin source emissions; 

• To provide air monitoring capability for the occurrences and levels of dioxin-like compounds in

areas where animal feeds (used to feed domestic livestock) are primarily grown;

• To provide for the long-term monitoring of dioxin-like compounds in different regions of the

U.S. and over different seasons; and,

• To provide data on potential transboundary import of dioxins and furans into the U.S.

The network is being developed in phases. Phase 1 consists of up to 20 air monitoring stations;

Phase 2 is expected to consist of about 30-40 stations. Additional information about the network can be

found at www.epa.gov/nceawww1/1page.htm. 

OTHER ENVIRONMENTAL MONITORING NETWORKS AND

DATABASES

The EPA’s Environmental Monitoring and Assessment Program

(EMAP)

In 1988, the EPA Science Advisory Board (SAB) recognized a deficiency in the documentation

of the status of the Nation’s natural environment and recommended that EPA develop a program to

monitor ecological status and trends in the U.S. The EPA responded with the initiation of the

Environmental Monitoring and Assessment

Program (EMAP) in 1989. The EMAP program

also collaborates with other agencies, including

NOAA.

The primary goal of EMAP is to

“monitor the condition of the Nation’s

ecological resources, to evaluate the cumulative

success of current policies and programs, and to

identify emerging problems before they become

widespread or irreversible” (U.S. EPA 1997i, j,

k). Knowledge from the EMAP process will

give decision makers the ability to make

informed environmental management decisions,

set rational priorities, and make known to the

public the costs, benefits, and risks of
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-9

proceeding or refraining from implementing specific regulatory actions. Four operational objectives

guide EMAP:

1. Estimate the current status, trends, and changes in selected indicators of the Nation’s ecological

resources on a regional basis with known confidence;

2. Estimate the geographic coverage and extent of the Nation’s ecological resources with known

confidence;

3. Seek associations between selected indicators of natural and anthropogenic stresses and

indicators of ecological resources; and,

4. Provide annual statistical summaries and periodic assessments of the Nation’s ecological

resources.

These four objectives create an innovative approach for EMAP, which adopts a comprehensive,

multimedia perspective of the Nation’s natural resources rather than the traditional single-pollutant or

single-location approach to environmental assessment.

 The EMAP’s strategy also includes the development of a Regional Environmental Monitoring

and Assessment Program (R-EMAP) to test the effectiveness of the EMAP approach on answering

questions about regional and local ecological conditions. The R-EMAP has three main objectives:

C To evaluate and improve EMAP concepts for State and local use;

C To assess the applicability of EMAP indicators at differing spatial scales; and,

C To demonstrate the utility of EMAP for resolving issues of importance to EPA Regions and

States.

Since 1990, EPA has funded at least two R-EMAP projects in each of the ten EPA Regions. One of these

studies addressed mercury deposition levels and geographic trends in the Great Lakes region, as

mentioned in Chapter II.

National Sediment Inventory

The EPA established the National Sediment Inventory (NSI) to prepare the first biennial National

Sediment Quality Survey (NSQS) Report to Congress (U.S. EPA 1997i, j, k) (see also page III-8). 

National-level results from the NSQS on sediment contamination are presented in Chapter II. The NSI is

intended to have applications far beyond supporting subsequent NSQS biennial reports. The NSI is the

largest set of sediment chemistry and related biological data ever compiled by EPA. In addition to

sediment chemistry data, the NSI includes tissue residue and sediment toxicity data. 
Chapter IV

Science and Tools

Page IV-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

NSI Federal Databases

ì EPA’s Storage and Retrieval System (STORET)

í NOAA’s Coastal Sediment Inventory (COSED)

î EPA’s Ocean Data Evaluation System (ODES)

ï EPA Region IV Sediment Quality Inventory

ð The Gulf of Mexico Program’s Contaminated 

 Sediment Inventory

ñ EPA Region X/USACE Seattle District’s 

 Sediment Inventory

ò EPA Region IX Dredged Material Tracking 

 System (DMATS)

ó EPA’s Great Lakes Sediment Inventory

ô EPA’s Environmental Monitoring and 

 Assessment Program (EMAP)

õ USGS’s Massachusetts Bay Data

The NSI includes data from ten existing

Federal databases (see sidebar). Minimal data

requirements for the NSI include monitoring

program, sampling date, latitude and longitude

coordinates, and measured units. Additional data

fields such as sampling method and other quality

assurance/quality control information are

included when available. At present, the NSI

contains approximately 2 million records for

more than 21,000 monitoring stations across the

country. More than 230 chemicals and chemical

groups are included. Only data from 1980 to

1993 were used for the first NSQS. However,

older data are available in the NSI.

Although the NSI provides broad

geographic coverage, the 21,000 monitoring stations currently represented in the data are not randomly

distributed. Most of the monitoring programs used to compile the NSI are located in areas with known or

suspected contaminant impacts. 

National Contaminated Sediment Point Source and Non-point

Source Inventories

The EPA’s mandate to investigate sediment contamination in the Nation’s water included a

directive to identify potential pollutant sources. With future biennial NSQS Reports to Congress, EPA

will inventory point and non-point sources and estimate loadings. The first NSQS Report to Congress

evaluated point sources (i.e., direct discharges to waterbodies) only (see also page III-8). The National

Contaminated Sediment Point Source Inventory (U.S. EPA 1997k) provided a relative ranking of

industrial categories and discharged chemicals for their potential contribution to sediment contamination. 

The EPA developed the “load score,” a unitless index of the magnitude of potential sediment

contamination based on chemical/facility-specific releases, physical and chemical properties, and

potential environmental risks. A screening analysis of the load scores indicated that the point sources

most likely to contribute to sediment contamination were sewerage systems, metals products and

finishing, primary metals industries, industrial organic chemicals, public utilities, petroleum refining, and

other chemical products. Metals were associated with higher load scores than other contaminant groups

because point source releases are more prevalent. Additional analyses are needed to assess the

bioavailability and toxicity of metals in sediments. 

Although the NSQS did not inventory specific non-point sources, it examined the land uses in

watersheds containing areas of probable concern (APCs) to identify potential relationships between

sediment contaminants and human activities. In general, EPA found that diversified land uses were

associated with diversified pollutants. However, a high percentage of agricultural land use corresponded

with markedly higher contamination from pesticides. Most chemical classes increased with higher

percentages of urban land use. The analysis suggested that mercury and PAHs in urban sediments may

be attributable to atmospheric deposition from local sources.

Although the National Contaminated Sediment Point Source Inventory identified metals as the

leading contaminants based on load scores, the NSQS identified PCBs, mercury, pesticides, and PAHs as

most often responsible for contamination levels of concern in sediment (see also page II-73). This
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-11

suggests that non-point sources and historical releases (including atmospheric deposition) contribute

largely to contamination in the Nation’s waters. 

NOAA’s National Status and Trends Bioeffects Assessments

The National Status and Trends (NS&T) Program under NOAA (see page II-70) conducts

bioeffects assessment studies, which include sediment toxicity surveys and the development of effectbased numerical guidelines for use in evaluating the toxicological relevance of sediment contamination,

among other factors. The sediment toxicity surveys are conducted in coastal areas where data from

NS&T’s Mussel Watch and Benthic Surveillance Projects indicate the potential for substantial

environmental degradation and biological effects. Bioeffects assessments have been or are being

conducted in 16 coastal areas. Reports and data sets are available on the Internet for several of these

locations at http://seaserver.nos/noaa.gov/projects/bioeffects/page1.html.

ENVIRONMENTAL TRANSPORT AND FATE

Available Environmental Transport and Fate Models

Models-3 Community Multi-Scale Air Quality (CMAQ) Modeling System

The Models-3 community multi-scale air quality (CMAQ) modeling system is a flexible software

system designed to simplify the development and use of environmental assessment and decision support

tools for applications ranging from regulatory and policy analysis to understanding the interactions of

atmospheric chemistry and physics. This newest generation of environmental modeling software has

been under development for the past 7 years. Models-3, in combination with CMAQ, form a third

generation air quality modeling and assessment system. First generation air quality models dealt with

tropospheric air quality with simple chemistry at local scales using Gaussian plume formulation (i.e., the

model assumes that the plume spreads from an emission source laterally and vertically in accordance

with a Gaussian distribution) as the basis for prediction. Second generation models covered a broader

range of scales (i.e., local, urban, regional) and pollutants, addressing each scale with a separate model

and often focusing on a single pollutant. Third generation models treat multiple pollutants

simultaneously up to continental scales and incorporate feedback between chemical and meteorological

components. Models-3 has a unique framework and science design that enables scientists and regulators

to build their own modeling systems to suit their needs. The CMAQ system has capabilities for urban to

regional-scale air quality simulation of tropospheric ozone, acid deposition, visibility, toxics, and fine

particles. The Models-3 framework contains components that assist the model developer with creating,

testing, and performing comparative analysis of new versions of air quality models and enables the user

to execute air quality simulation models and visualize the results. The overall goal of Models-3 is to

simplify and integrate the development and use of complex environmental models, beginning with air

quality and deposition models (U.S. EPA 1998e). It is expected that the Models-3 framework and

CMAQ will be useful tools for research related to the Great Waters program.

The initial public release of the Models-3 framework occurred in June 1998. This framework

provides a unifying foundation for continued evolution of environmental modeling and assessment tools

with the ability to extend the capabilities beyond the current air quality implementations. One area of

investigation has been a basic integration of the Chesapeake Bay Water Quality Model (CBWQM) into

the Models-3 framework to explore multimedia model linkages. Future development toward a fourth

generation system will extend linkages and process feedback to include air, water, land, and biota to
Chapter IV

Science and Tools

Page IV-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

provide a more holistic approach to simulation of transport and fate of chemicals and nutrients

throughout an ecosystem (U.S. EPA 1998e).

Total Risk Integrated Methodology (TRIM)

The Total Risk Integrated Methodology (TRIM) is a comprehensive framework for

characterizing human health and ecological risk. It is being designed by EPA’s Office of Air Quality

Planning and Standards (OAQPS) for use in CAA programs (e.g., the Residual Risk Program) as a way to

consistently estimate the impacts of air pollutants. The TRIM will have the following characteristics: (1)

ability to perform multimedia assessments; (2) ability to perform human health and ecosystem risk

assessments; (3) ability to perform multipollutant assessments; (4) capability to address

uncertainty/variability; and, (5) ability to provide a readily available, user-friendly tool that will assist in

risk management decisions (U.S. EPA 1999e).

The EPA is attempting to create a system that is scientifically defensible, flexible, and user

friendly. The format of input data sets to TRIM are consistent with Models-3. When complete, TRIM

will contain three separate modules, including (1) fate and transport, (2) exposure, and (3) risk

characterization. The most complex module is the multimedia fate and transport module, which is

entitled TRIM.FaTE. This is the module on which EPA has been concentrating most of its effort (U.S.

EPA 1999e).

The TRIM.FaTE module is a multimedia, chemically mass-balanced model. In the model, the

ecosystem scale of interest (landscape) is divided into compartments. The model tracks the mass of the

pollutant transported between compartments (rather than a set of one-way fate algorithms). The model is

being designed so that a wide variety of pollutants can be addressed. The TRIM.FaTE module will have

the capability to (1) simulate steps in a time series and (2) resolve mass distribution spatially. A

prototype version of TRIM.FaTE has been developed by EPA; however, significant work remains on this

module, including comparisons of output to monitoring data for case studies and other model evaluation

exercises. A version of TRIM, including TRIM.FaTE, is expected to be released in 2000 (U.S. EPA

1999e).

Models for Atmospheric Mercury

Because of the need to identify the emission reductions required to meet water quality and other

criteria, systems are being developed that use emissions data with atmospheric chemistry and transport

models and meteorological models. A report, A Computer-Based Framework to Model Acceptable

Loadings of Mercury to the Atmosphere to Protect Water Quality, was prepared for EPA Region IV by

Nicola Pirrone and Gerald J. Keeler, at the University of Michigan (Pirrone and Keeler 1997). This

report discusses the coordination of available computer models for atmospheric mercury – its transport,

chemical-physical dynamics, and deposition (wet and dry) to water surfaces and terrestrial receptors. 

The analysis of model capabilities and critical data inputs is applicable nationwide. In addition, some

specific discussions are provided for the South Florida Everglades in comparison to forested watershed

and lake systems.

This report presents a framework linking models that relate data on mercury emissions into the

air to subsequent mathematical modeling of atmospheric transport, chemistry, and deposition processes

(Pirrone and Keeler 1997). The modeling framework is designed so that regulatory agencies can define

target load reductions from local and regional sources that are needed to meet water quality goals. In

order to correctly relate water quality criteria and bioaccumulation of mercury in the food chain to the

atmospheric and other inputs, this modeling framework needs to be coupled to an aquatic modeling

system utilizing mercury transport and fate processes in similar timeframes. The set of models in the
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-13

framework will need inputs including watershed-specific information or default assumptions and

chemical species released from the major pollutant sources, along with meteorological data and

mesoscale models (such as RAMS from Colorado State University or MM5 from Pennsylvania State

University). This conceptual framework of models is being used as part of the design and analyses in a

State/EPA pilot project to develop a TMDL for mercury in a specified section of the Florida Everglades,

as discussed in Chapter III.

The Electric Power Research Institute (EPRI) has developed and continues to develop

environmental mercury cycling models (MCMs) to assess the transport and fate of atmospheric mercury

(Watras and Huckabee 1994, Leonard et al. 1995, Logan 1998, Pai et al. 1999). The MCMs have been

used to predict the fate of mercury in the Great Lakes (Leonard et al. 1995). The Maryland Department

of Natural Resources reviewed two EPRI models, the Lake MCM (L-MCM) and the Regional MCM (RMCM), and concluded that they had the potential for use in Maryland to investigate cycling of

environmental mercury and bioaccumulation in fish (Logan 1998). The L-MCM was developed for

predicting the biogeochemical behavior of mercury in the Mercury in Temperate Lakes Study of seepage

lakes in Wisconsin. The L-MCM is a dynamic, mechanistic simulation model that tracks processes and

changes in concentrations through time. The R-MCM is a steady-state, mechanistic simulation model.

Recent Environmental Transport And Fate Modeling Results

Atmospheric Exchange Over Lakes and Oceans Surfaces (AEOLOS) 

The Atmospheric Exchange Over Lakes and Oceans Surfaces (AEOLOS) project, administered

through the EPA Great Lakes National Program Office and the Office of Research and Development, was

designed to study atmospheric deposition in the Great Waters. Begun in 1993 by EPA and scientists

from the Universities of Minnesota, Michigan, Maryland, Delaware, and the Illinois Institute of

Technology, the project’s objectives were to determine (1) the dry depositional fluxes of critical urban

contaminants to the northern Chesapeake Bay near Baltimore and southern Lake Michigan near the

Chicago urban area, (2) the contributions of urban source categories to measured atmospheric

concentrations and deposition, and (3) the air-water exchange of contaminants and their partitioning into

aquatic phases (U.S. EPA 1997b). The AEOLOS project proceeded under the hypothesis that emissions

of HAPs into the coastal urban atmosphere enhance atmospheric depositional fluxes to the adjacent Great

Waters such as Lake Michigan in the vicinity of Chicago and Gary, Indiana, and the Chesapeake Bay

near Baltimore (Simcik et al. 1997). Results of some AEOLOS studies are reported in Chapter II for

PAHs and PCBs as well as below.

A study under the AEOLOS project found that urban air emissions have an effect on the average

coastal atmospheric concentrations of PAHs and PCBs above continental background, increasing them by

factors of 12 and 4, respectively. As part of AEOLOS, air concentrations of PCBs and PAHs were

measured in the urban/industrial complex of Chicago, over the southern portion of Lake Michigan, and in

a non-urban location, in May and July 1994 and January 1995. Gas-phase PAH and PCB concentrations

over the lake were much lower than urban air concentrations. The highest concentrations were

associated with winds that first crossed-over the urban/industrial area from Evanston, Illinois to Gary,

Indiana. Concentrations were near regional background for winds from any other direction. Seasonal

variation of PCB occurred, with volatilization being higher during the summer (Simcik et al. 1997).

In another AEOLOS study in the Chicago area, PCB concentrations in wet precipitation collected

over southern Lake Michigan ranged from two to as high as 400 times greater than the measured regional

background concentration, indicating that the “urban plume” of Chicago increases atmospheric

deposition of contaminants to Lake Michigan over tens of kilometers. Concentrations of PCBs in urban
Chapter IV

Science and Tools

Page IV-14 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

precipitation were dominated by particle-bound congeners, indicating PCB enrichment in rainwater due

to efficient scavenging of contaminated particulate matter in the urban atmosphere (Offenberg and Baker

1997).

Simcik et al. (1998), under the AEOLOS project, investigated gas-particle partitioning of PCBs

and PAHs in the Chicago urban area and over Lake Michigan and found that PCBs and PAHs in the

Chicago/Lake Michigan atmosphere were at equilibrium between the gas and particle phases. 

Understanding gas-particle partitioning is important because it can be used to help determine the mode of

atmospheric deposition (i.e., wet deposition, dry deposition, air-water exchange).

Chesapeake Bay NOx Modeling with RADM

The Regional Acid Deposition Model (RADM) has been used to develop estimates of the

primary airshed of NOx emissions that are contributing nitrogen deposition to the Chesapeake Bay

watershed. The RADM was originally developed to address policy and technical issues associated with

acidic deposition. The model is designed to provide a scientific basis for predicting changes in

deposition resulting from changes in precursor emissions, to predict the influence of sources in one

region on acidic deposition in other sensitive receptor regions, and to predict the levels of acidic

deposition in certain sensitive receptor regions (Dennis 1997).

In the RADM, the concentrations of gaseous and particulate species are calculated for specific

fixed positions in space as a function of time. The geographic extent, or domain, of the model is 2,800

by 3,040 km and extends south from James Bay in Canada to the southern tip of Florida and westward to

central Texas. This domain is partitioned into 80 km-by-80 km grid cells. The space is threedimensional, having 15 logarithmically-spaced vertical layers, covering the distance from ground level to

16 km in altitude. The RADM has a chemistry component that consists of 140 reactions among 60

species. Chemical decomposition by solar radiation and aqueous-phase reactions that occur in clouds are

both included in the model’s chemistry. For each grid cell, predictions are generated at dynamically

determined time steps of seconds to minutes that are output hourly by the model. The species predicted

by RADM include ambient concentrations (SO2, NO, NO2, HNO3, O3, H2O2, NH3, PAN, HCHO, CO, and

SO4

=

), wet deposition (SO4

=

, NO3

-

 as HNO3, NH4

+

 as NH3, and H+), and dry deposition (SO2, SO4

=

, HNO3,

O3, and NO2). The meteorological fields that are used to determine the turbulent motion of the

atmosphere, which in turn affects the transport of species by wind into and out of the grid in three

dimensions, are from the Pennsylvania State University, National Center for Atmospheric Research

Mesoscale Model (MM4). The MM4 is a weather model used to recreate historical meteorology.

Recent analysis with RADM shows that the range of influence of nitrogen emissions is similar to

the range for sulfur emissions – on the order of 600 - 800 km. However, results suggest that the nitrogen

range given is too short (Dennis 1997). This implies the range for nitrogen should be longer than that for

sulfur. In other words, the RADM results and analysis used to define the airshed for the Chesapeake Bay

watershed is producing an estimate of the boundary of the airshed that is conservative, that is, one that is

too small.

In the original 1995 study (Dennis 1997), the extent of the Chesapeake Bay airshed was

approximately 900,000 km2, or more than 51⁄2 times larger than the watershed. The NOx emissions in the

airshed account for approximately 75 percent of the anthropogenic nitrogen deposition to the Chesapeake

Bay watershed. More recently, using the same methodology, Dennis conducted a more refined analysis

of the subregions within the RADM domain, resulting in a revised estimate of the Chesapeake Bay

airshed. This revised airshed, presented in Figure IV-2, is approximately 1,081,600 km2, making it about

61⁄2 times larger than the watershed (see http://www.chesapeakebay.net/data/model/mod_gis/

air_dom.gif). This larger airshed estimate results in only a slight increase (76 percent) of the amount of
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-15

NOx emissions from the airshed which are deposited to the watershed. The contribution from utility and

mobile sources are roughly equal and make up the majority of the emissions which are eventually

deposited. However, when model simulations are used to compare these emission sources to nitrate

deposition a significant pattern emerges. Utilities, which are heavily concentrated to the west of the Bay,

tend to contribute a majority of the nitrate that deposits on the western side of the watershed. Moving

across the watershed from west to east, nitrate deposition from utility emissions shows a decreasing

trend. In contrast, a large amount of the mobile source emissions take place in cities and heavily

developed areas relatively close to the Bay. Thus, mobile emissions tend to contribute a majority of the

nitrate that deposits along the Delmarva Peninsula, the Chesapeake Bay itself, and the lower portions of

the western shore tidal tributaries. Nitrate deposition from mobile emissions shows a decreasing trend

moving from east to west across the watershed (Dennis 1997).

Figure IV-2

Revised Principal Airshed for the Chesapeake Bay

(Developed by R. Dennis, Atmospheric Sciences Modeling Division: ARL, NOAA, and NERL U.S. EPA)

Lake Michigan Mass Balance Study

The Lake Michigan Mass Balance Study (LMMBS) was developed and is being implemented by

the Great Lakes National Program Office in cooperation with five U.S. Federal agencies (i.e.,

Department of Energy, NOAA, U.S. Geological Survey, U.S. Fish and Wildlife Service, U.S. Army

Corps of Engineers), one foreign agency (i.e., Environment Canada), two State agencies, and eight

academic institutions. The LMMBS was initiated to address the objectives of the Lake Michigan

Monitoring Program, as well as to assist EPA in implementing section 112(m) of the CAA by

characterizing the loadings, transport, and fate of selected pollutants through monitoring and modeling. 

The Second Great Waters Report to Congress describes the project in more detail and describes the
Chapter IV

Science and Tools

Page IV-16 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

atmospheric monitoring efforts, a system of ten stations situated around Lake Michigan. Additional

information can be found at www.epa.gov/glnpo/lmmb. The ultimate goal is to develop a predictive

model that forecasts impacts on lakes based on inputs of toxics to the system from a variety of sources

(sediments, atmospheric deposition, tributaries). Preliminary modeling results for mercury are presented

in Chapter II. Additional results are expected in 2000 that will support, in addition to section 112(m),

such efforts as the Binational Toxics Strategy and LaMPs. 

The LMMBS model is constructed for a limited group of pollutants: PCBs, chlordane, total

mercury, and atrazine. For mercury and atrazine, an emissions inventory either existed or could be

developed, so comprehensive modeling is being conducted for these two pollutants. For PCBs and

chlordane, a comprehensive modeling approach was not attempted because a comprehensive emissions

inventory did not exist. In addition, monitoring data were collected for an extended suite of chemicals,

including additional pesticides, PAHs, and heavy metals. Currently, a multimedia database is being

developed to house all the data and quality assurance information for use by the modelers. In the future,

the data will be available upon request. 

Atmospheric loadings of the LMMBS pollutants are being calculated for input into the models. 

A major finding of the LMMBS to date is that traditional atmospheric loading estimation techniques are

not adequate to describe the variability and source influence on deposition to the lake. New techniques

have been developed to better characterize the impact of atmospheric deposition on large lake systems. 

Efforts have also been made to coordinate with ongoing fate and transport modeling activities and to

support the most advanced developments. The LMMBS is contributing a major amount of resources to

the CMAQ model system (page IV-11) for use in estimating emissions and transport of atrazine and

mercury to Lake Michigan. In addition, this project has assisted in the development of an atrazine soil

emissions model that could also be used to develop emissions inventories in other regions.

Recent REMSAD Applications

The Regulatory Modeling System for Aerosols and Deposition (REMSAD) was originally

developed in part to address the issue of atmospheric deposition of HAPs to the Great Waters. The

REMSAD is a grid model designed for use on workstation-class computers. As currently configured,

REMSAD (version 4.0) tracks the transport, transformation, and deposition (both wet and dry) of

nitrogen, mercury, cadmium, dioxin, polycyclic organic matter (POM), atrazine, speciated primary and

secondary fine particles, photochemical oxidants, acids, and ammonia. All of these substances are

treated simultaneously for a single integrated emission inventory, so that the effects of proposed policy

options on multiple pollutants with common sources may be analyzed at the same time. The model

extends vertically all the way to the tropopause, so that long-range transport of pollutants in the upper

troposphere can be captured.

The model is capable of nesting finer (i.e., higher resolution) grids within an overall coarse grid,

which makes it possible to focus on deposition to a particular watershed within the context of a broad

regional distribution of emission sources. The EPA recently sponsored the 1990 Base Case Evaluation

Study (Guthrie et al. 1999a, b) in which the National Emission Trends 1990 inventory was used, along

with a calendar 1990 meteorological data set produced by the Interagency Working Group on Air Quality

Models (IWAQM). This model run was conducted for a full year (less 5 days) for the contiguous U.S.

with adjacent portions of Canada and Mexico. The run was carried out on a coarse grid of approximately

60 km resolution, but included seven nested sub-grids at approximately 20 km resolution. These nested

sub-grids focused on the eastern seaboard (especially around the Chesapeake Bay), the Lake

Michigan-Lake Superior region, the northern Gulf of Mexico, Puget Sound, southern Florida, and the

Houston-Galveston region of Texas.
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-17

The annual deposition pattern of total wet and dry nitrogen deposition (as nitrate) as simulated in

the 1990 Base Case is very similar to that reported by Dennis (1997) for the eastern U.S., given

differences in emissions. The REMSAD results indicate a significant seasonal variation, however,

especially in the wet deposition fraction, as might be expected. The pattern of mercury deposition from

the same model run is similar overall to that seen in the RELMAP simulations reported in the Mercury

Study Report to Congress (U.S. EPA 1997e), but the localized “hot spots” are more prominent. 

In another context, REMSAD has been used in a study to assess the most efficient combination

of NOx controls designed to reach specified reduction levels in nitrogen reaching the Chesapeake Bay via

atmospheric deposition. In this application, the total reduction desired is held fixed, but the combination

of air quality health benefits attributable to NOx in various locations is combined with specific costs of

NOx reductions in those locations. This forms the basis for both a least-net-cost analysis and for a

potential emission trading approach based on spatially differentiated values for NOx emission reductions

(Krupnick et al. 1998). 

Recent Environmental Transport and Fate Research

The Fate of Mercury in the Lake Superior Basin

This project, which began in 1998, is designed to examine mercury sources and deposition in the

Lake Superior basin, particularly the contribution of a coal-fired power plant to the mercury loading of

local and regional ecosystems. The research is being conducted at the Minnesota Power and Light’s Clay

Boswell Station and at the Wisconsin Electric Power Company’s Presque Isle Power Plant and is

expected to answer questions about what forms of mercury are emitted, and how much mercury from the

power plant is deposited locally compared to regionally. The overall goal of the project is to determine

the fate of anthropogenic mercury in the Lake Superior region, thereby allowing the prediction of the

effects of mercury reduction strategies on the bioaccumulation of methylmercury in fish. The project is

expected to be completed at the end of 2000.

Sources and Impacts of Nutrient Enrichment in the Gulf of Mexico

Nutrient enrichment in the northern Gulf of Mexico is responsible for one of the largest zones of

oxygen-deficient bottom waters in the western Atlantic Ocean. To address this problem, the White

House’s Committee on Environment and Natural Resources (CENR) established a multiagency scientific

team to review the extent and causes (including air pollution sources) of hypoxic waters, the ecological

and economic impacts of hypoxia on the gulf, and potential solutions. Specifically, the multiagency team

identified six topics of study:

1. Distribution, dynamics, and causes of hypoxia in the gulf;

2. Ecological and economic consequences of hypoxia in the gulf;

3. Sources and loads of nutrients to the gulf from the Mississippi River;

4. Effects of reducing nutrient loading to the Mississippi River and the

gulf;

5. Methods to reduce nutrient loads; and,

6. Social and economic costs and benefits of nutrient reduction strategies.
Chapter IV

Science and Tools

Page IV-18 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

The scientific assessments for the above six topics of study are complete and available at

www.nos.noaa.gov/products/pubs_hypox.html. The integrated assessment, which will address all six

topics together, is currently under review and will be available later in 2000. These assessments will be

used by the Gulf of Mexico Program, State agencies, and other involved agencies to combat nutrient

enrichment and hypoxia and measure progress toward the goal of a restored Gulf of Mexico ecosystem.

Pollutant Exchange Mechanisms

Many pollutants, depending on their specific chemical and physical properties, can be transferred

between environmental media. In recent years, research has focused primarily on the exchange of

pollutants between air and water. The major air-water transfer processes include wet and dry

atmospheric deposition, gaseous exchange, bubble stripping and bursting, and spray transfer (Gustafson

and Dickhut 1997). In 1996, Hoff et al. reported on revisions to the estimates of atmospheric inputs of 11

organochlorine (OC) chemicals, five trace elements, and four PAHs to the Great Lakes based on IADN

data. Calculations include the flux for wet deposition, dry deposition, and vapor transfer across each of

the lakes, with highest confidence in the estimates for wet deposition and lowest confidence in the

estimates for gas transfer components. Polychlorinated biphenyls, dieldrin, HCB, DDE, phenanthrene,

and pyrene all showed net losses from the lakes to the atmosphere via volatilization, while p,p’-DDT was

loaded into the lakes from the atmosphere. Alpha- and (-HCH were near equilibrium with the

waterbodies and the atmosphere, with seasonal changes for "-HCH. These results show that the waters

of the Great Lakes are close to long-term equilibrium with the atmosphere for most of these chemicals,

but that equilibrium is in a constant state of short-term seasonal displacement and adjustment (Mackay

and Bentzen 1997). There is a need, however, for integrated assessments of air-water transfer (i.e.,

measuring both water and air simultaneously and over widely varying conditions) for each lake to obtain

reliable estimates of distribution coefficients, deposition velocities, and loadings from other sources.

More recently, Gustafson and Dickhut (1997) quantified the gaseous exchange fluxes for PAHs

across the air-water interface of the southern Chesapeake Bay and demonstrated that, for individual

PAHs, different particle characteristics influenced particle-gas distributions at the urban and rural sites. 

Atmospheric PAH concentrations were measured at four sites that were characterized as rural, semiurban, urban, and industrialized. Exponential increases in gaseous PAH concentrations with temperature

were observed at the non-rural sites, which the authors suggested was volatilization from contaminated

surfaces during warmer weather. The PAH gas concentrations at the rural site exhibited little seasonal

variability. Aerosol particle-associated PAH levels were similar at all sites and increased in winter. This

was attributed to the temperature dependence of particle-gas partitioning, including the cold

condensation of gases to background aerosols as air masses were dispersed from source areas to remote

regions, and also increased emissions from combustion of fossil fuel and wood for home heating during

the wintertime. Indications were that either PAH partitioning is not at equilibrium or that different

distribution processes were operating in rural areas of southern Chesapeake Bay. 

Nelson et al. (1998) measured the dissolved- and gas-phase concentrations of nine PAHs and 46

PCB congeners at eight sites on the Chesapeake Bay at four different times of the year to estimate the

diffusive exchange of gaseous PAHs and PCBs across the air-water interface. They found that PAH

fluxes varied both temporally and spatially in the Chesapeake Bay. Fluxes were usually larger in the

northern bay as a result of higher gaseous concentrations. Gaseous PAHs were absorbed into the bay’s

surface waters during the spring, and lighter compounds revolatilized in the late summer and early fall

due to seasonal changes in surface water temperature and atmospheric PAH levels. On an annual basis,

Nelson et al. found that the atmosphere is a net source of volatile PAHs to the bay and that gas absorption

may be the largest external source of fluorene and phenanthrene, providing up to three times the

combined loadings from wet and dry aerosol deposition and from the tributaries. In contrast to PAHs,

PCBs volatilized from Chesapeake Bay throughout the year, with the largest fluxes occurring in
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-19

September due to high dissolved concentrations and warmer water, while the smallest fluxes occurred

during stratification in June when both dissolved phase concentrations and wind speeds were low.

A study by Ridal et al. (1997) found that as much as 60 percent of the "-HCH in the air above

Lake Ontario was derived from the lake itself. Another study of air and water samples from the Bering

and Chukchi Seas and on a transect across the polar ice cap to the Greenland Sea concluded that soils and

surface waters containing HCH will be a diffuse, non-point source to the atmosphere that will likely

maintain detectable atmospheric concentrations for some time into the future (Jantunen and Bidleman

1996, Li et al. 1998). 

Hurley et al. (1998a) investigated partitioning and transport of total mercury and methylmercury

in the lower Fox River in Wisconsin and found that resuspended sediments were the predominant source

of mercury from the Fox River into the Green Bay. The researchers coupled time series data of total

mercury at the river mouth with transect sampling in the Lower Fox River. The researchers reported that

concentrations of unfiltered total mercury were significantly elevated compared with other large

tributaries to Lake Michigan. The transect sampling revealed progressively increasing water column

total mercury concentrations and total mercury particulate enrichment downstream, which the authors

suggest were consistent with trends in sediment total mercury levels in the river. Despite elevated total

mercury concentrations, Hurley et al. (1998a) reported that methylmercury concentrations were relatively

low, suggesting limited bioavailability of total mercury associated with sediments.

The processes that take place in the water surface microlayer, particularly those related to

pollutant exchange mechanisms at the air-water interface, are receiving increasing attention in the

research literature as one of the most important regions of large surface waterbodies. The surface

microlayer is the top 30 to 300 μm of a waterbody where atmospheric pollutants first deposit. 

Hydrophobic contaminants, such as PCBs, can adsorb at the air-water interface even without previous

organic accumulations present due to the lower energy state of the interface. The accumulation of

organic matter in the surface microlayer also causes a lowering of surface tension values, resulting in

further enrichment of the organic matter in the surface microlayer as compared to the subsurface water. 

As a result of its organic nature, many pollutants concentrate in the surface microlayer, especially

hydrophobic organic contaminants such as PAHs, PCBs, and other pollutants that adhere to particles or

exhibit increased solubility with elevated dissolved organic matter. Yet, despite its importance, the

surface microlayer is possibly the least understood and poorly characterized region of the aquatic

environment.

Liu and Dickhut (1997) compared PAH enrichment in the surface microlayer at an urban site

(Elizabeth River) and a semiurban site (York River) in the southern Chesapeake Bay watershed and

found particulate PAH concentrations in the surface microlayer of the Elizabeth River to be an order of

magnitude higher than in the York River. In comparing the enrichment of PAHs in the surface

microlayer relative to subsurface water, total PAH concentrations in the surface microlayer were found to

be 1-4,900 times higher. The authors speculated that the difference in PAH concentrations in the surface

microlayers of the two rivers was due to a greater contribution of atmospheric deposition of soot-like

aerosols to the surface microlayer in the urban Elizabeth River.

Liu and Dickhut (1998) concluded that wind-driven mixing is the principal mechanism that

distributes suspended particles collected at the air-water interface into the surface microlayer. The

researchers found a significant relationship (p < 0.05) between wind speed and the surface microlayer

thickness at the York River site. Thicker surface microlayers result in greater enrichments of organic

material. Liu and Dickhut (1998) also concluded that enrichment of suspended particles and organic

carbon in the surface microlayer is related to the sources of these materials in aquatic ecosystems. In the

York River, where in situ production of organic matter plays a greater role than runoff and atmospheric
Chapter IV

Science and Tools

Page IV-20 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

deposition, enrichment of the surface microlayer appeared to be related to the buoyancy and density of

the particle types. In contrast, in the Elizabeth River, where productivity is lower, small, dense particles

presumably derived from runoff and atmospheric deposition appeared to accumulate in the surface

microlayer.

MEASURING AND MONITORING TECHNIQUES

Ambient Mercury

Some of the most important new developments made during the last few years of atmospheric

mercury research were reliable methods developed to measure reactive (divalent) gaseous mercury

species (Hg+2). The importance of developing a reliable method for measuring ambient Hg+2 (in the

picogram per cubic meter range) was identified as the highest priority research topic at the expert panel

on Mercury Atmospheric Processes convened on March 16-18, 1994 in Tampa, Florida. Researchers

from the U.S. and Europe reported observing significant spatial gradients in mercury deposition around

urban and industrial areas, indicating local anthropogenic influences. The panel considered improved

characterization of mercury species from sources and at impacted receptor locations to be vital to

elucidate source-receptor relationships.

Over the past several years, three different methods to measure ambient Hg+2 have been

proposed, including impregnated filters (Gill et al. 1996), refluxing mist chambers (Lindberg and Stratton

1998), and thermal annular denuders (Stevens et al. 1998a). An instrument utilizing thermal denuder

technology recently has been introduced by Tekran Inc. that is capable of continuously measuring both

Hg0 and Hg+2 (Stevens et. al. 1998b). Determining the applicability of this new Tekran instrument in

establishing a national automated mercury monitoring network was recommended at the October 1998

Tri-lateral Commission for Environmental Cooperation meeting in Las Vegas, Nevada. The EPA’s

National Exposure Research Laboratory is presently evaluating the accuracy and precision of the

available ambient Hg+2 measurement technologies in order to determine which may be better for routine

monitoring purposes.

A method for collection and analysis of total particulate mercury (Hgp) was recently published in

the EPA Compendium of Methods for the Determination of Inorganic Compounds in Ambient Air

(Method IO-5). Air is pulled through a pre-fired glass filter, which is subsequently microwave digested

in nitric acid. The filter extract is then analyzed using cold vapor atomic fluorescence spectrometry

(CVAFS). A semi-continuous method for Hgp determination was developed by Lu et al. (1998). 

Ambient samples are collected onto a quartz filter housed in a quartz chamber. The quartz chamber is

then heated to 900EC releasing the Hgp as elemental Hg0, which is quantified using CVAFS. Research is

currently under way to merge the thermal quartz filter Hgp technique with the Tekran automated mercury

instrument so that the three most prevalent forms of mercury can be measured at ambient concentration

levels.

Source-Receptor Linkages

A combination of certain analytical techniques with appropriate modeling approaches has been

used on a number of occasions to ascertain sources contributing certain contaminants in receptor

matrices. Some of these studies have been conducted in geographic locations outside the Great Waters;

however, the methods may prove useful in linking sources and receptors in the Great Waters.

Using a combination of statistical and radioisotope dating techniques, Huntley et al. (1998) found

that the majority of dioxin and furan loads in Newark Bay Estuary sediments were attributable to
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-21

combustion sources and sewage sludge sources. Fifty sediment cores were collected throughout Newark

Bay and analyzed for dioxins and furans. In addition, the cores were dated using radioisotopic

techniques. The samples were grouped into three categories based on their estimated dates of deposition,

and polytopic vector analysis was performed separately on each group to determine the congener

fingerprint patterns. The congener fingerprint patterns were used to identify the source of contamination.

Biegalski et al. (1998) used source-receptor modeling to attribute metal concentrations in the air

at three sites near Lake Ontario to sources including oil and coal combustion units, mines, incinerators,

and smelting operations. Air samples were collected at the three sites and analyzed for trace elements by

neutron activation analysis. Factor analysis, elemental ratios, and enrichment factor analysis were used

to determine source-receptor relationships at the three sites.

Another new technique used to trace persistent organic pollutants to their sources is the

measurement of the enantiomeric ratios of chiral pollutants in the environment (Ridal et al. 1997,

Jantunen and Bidleman 1996). For example, information about the enantioselective degradation

organochlorine pesticides in soils (e.g., Aigner et al. 1998) could be coupled with data on the

enantiomeric composition of the compounds at the point of deposition to help determine pollutant

sources.

Using the technique of chemical mass balance, Su and Christensen (1997) determined that coalfired power plants, municipal waste incinerators, and pentachlorophenol use areas were major sources of

dioxins and furans in the Housatonic River (CT), Lake Huron, and the Baltic Sea. Other studies reported

in recent years examining source-receptor linkages include an investigation of source-receptor

relationships for mercury in South Florida (Dvonch et al. 1998) and stable isotope analysis for

characterization of pollutants at high elevation alpine sites (Pichlmayer et al. 1998).

EXPOSURE AND EFFECTS RESEARCH

Endocrine Disruptors

Endocrine disruptors cause adverse effects by interfering with the normal operation of the

endocrine system. These chemicals can act in a variety of ways, such as by mimicking natural hormones

or by blocking natural hormones. For example, p,p’-DDE (a breakdown product of DDT) has been

shown to inhibit the binding of androgen, a male hormone, to receptors (U.S. EPA 1997b). By

interfering with the endocrine system, endocrine disruptors may cause changes in homeostasis,

reproduction, and development. Also, since the neural and immune systems are closely linked to the

endocrine systems, endocrine disruptors may also act as immunosuppressant and neurotoxins. The

Second Great Waters Report to Congress (U.S. EPA 1997b) provides more detail about the possible

mechanisms of endocrine disruption.

The Second Report to Congress acknowledged that a growing body of animal and human data

suggests that a number of the Great Waters pollutants of concern potentially act as endocrine disruptors. 

The report specifically identified 11 of the 15 Great Waters pollutants of concern as possible endocrine

disruptors in wildlife: chlordane, dieldrin, DDT/DDE, hexachlorobenzene, lead, lindane, mercury (in the

form of dimethylmercury), PCBs, dioxins, furans, and toxaphene. These 11 chemicals, as well as

polycyclic organic matter, were also listed as potentially affecting the endocrine system in humans. 

Since the Second Report to Congress, scientific research on endocrine disruptors has continued to

provide evidence of their adverse effects in wildlife and humans. In addition, EPA recently developed a

draft screening and testing approach for systematically identifying endocrine disruptors and quantifying

their effects.
Chapter IV

Science and Tools

Page IV-22 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Workshop on Perinatal Exposure to Dioxin-like

Compounds

The workshop, which was held June 13-15, 1993 in

Berkeley, California, considered the effects of

perinatal exposure to chemicals such as dioxins,

furans, and PCBs on the reproductive, endocrine,

neurodevelopmental, and immune systems. 

Lindström et al. (1995) concluded that many of the

observed effects of these compounds suggest they

act as endocrine disruptors. They further proposed

that neurobehavioral effects (e.g., spatial

learning/memory and motor deficits) may be caused

by complex interactions between neuroendocrine and

neurophysiological systems.

Recent Research

Some research on endocrine disruptors is

focused on the role of the endocrine system in

prenatal and perinatal development (see sidebar). 

Development is under hormonal control, and a

precise integration of multiple endocrine systems

is required in all stages of development. 

Developmental effects traditionally have been

thought of as physical birth defects; however, this

view has been expanded to consider the proper

functioning of the individual throughout its life

cycle. Environmental pollutants that mimic,

block, or modulate the chemical messengers of

the endocrine system can cause a variety of

functional developmental deficits (e.g., impaired learning, memory, motor skills). For example, the

Second Report to Congress describes several findings of a study of children whose mothers ate PCBcontaminated fish from Lake Michigan. In this study, children born to mothers consuming the greatest

amount of contaminated fish exhibited impaired neurobehavioral ability (e.g., reflexes and response to

stimulation) as infants and impaired intellectual function (e.g., IQ, reading comprehension) at school age

(U.S. EPA 1997b). The interim findings of two new epidemiology studies support the results of the Lake

Michigan study. These effects are important to the Great Waters program because the endocrine

disrupting pollutants found in Great Waters fish tissue may be entering the waterbody through

atmospheric deposition, among other pathways.

C The Oswego Newborn and Infant Development Project was begun to examine the behavioral

effects in human newborns, infants, and children of maternal consumption of Lake Ontario fish

that were contaminated with a wide range of persistent toxic chemicals, including several Great

Waters pollutants of concern such as PCBs, hexachlorobenzene, dioxins, dieldrin, lindane,

chlordane, cadmium, and mercury. Interim study results indicate that newborns of women who

consumed high levels of fish from Lake Ontario performed lower on tests of neurobehavioral

ability (e.g., reflexes, physiologic responses to stress, and reactivity to stimulation) (Lonky et al.

1996).

C A group of researchers in the Netherlands studied the effects of prenatal exposure to PCBs

(estimated from levels in mother during pregnancy) and perinatal exposure to PCBs and dioxins

(measured in breast milk) on the psychomotor and mental development of infants (KoopmanEsseboom et al. 1996). At 3 months of age, infants with higher prenatal exposure to PCBs had

slightly lower psychomotor scores. At 7 months of age, psychomotor development was

negatively influenced by perinatal PCB and dioxin exposure. There was no significant influence

of the perinatal PCBs and dioxin exposure on mental development at 3 and 7 months of age. 

Endocrine Disruptor Screening and Testing Advisory Committee

The 1996 Food Quality Protection Act and the 1996 Safe Drinking Water Act Amendments

mandated that EPA “develop a screening program, using appropriate validated test systems and other

specifically relevant information, to determine whether certain substances may have an effect in humans

that is similar to an effect produced by a naturally occurring estrogen, or other such endocrine effect as

the Administrator may designate.” According to these mandates, EPA was required to develop this

screening program by August 1998, implement the program by August 1999, and report to Congress on
Chapter IV

Science and Tools

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page IV-23

the program’s progress by August 2000. In response, EPA formed the Endocrine Disruptor Screening

and Testing Advisory Committee (EDSTAC) and charged the committee with designing a screening and

testing program for endocrine disrupting chemicals. The EDSTAC was composed of representatives

from EPA, other Federal agencies, State agencies, various sectors of industry, water providers, worker

protection organizations, national environmental groups, environmental justice groups, public health

groups, and research scientists.

The EDSTAC’s final report was released in August 1998 (U.S. EPA 1998c). The report outlines

a tiered approach for detecting endocrine disrupting chemicals and quantifying their effects. Under this

system, chemicals may be subjected to high throughput pre-screening, tier 1 screening, tier 2 testing,

and/or hazard assessment. In the report, EDSTAC recommended specific assays that would be

conducted at each step; however, at present, none of the assays are fully validated. The recommended

assays address the need to consider multiple species and endpoints because historic reliance on existing

test species and endpoints was insufficient to appropriately screen, test, and characterize the risks from

endocrine disruption.

The EDSTAC estimated that approximately 87,000 chemicals need to be considered for

endocrine disruptor screening and testing, including pesticides, commodity chemicals, naturally

occurring non-steroidal estrogens, food additives, cosmetics, nutritional supplements, and representative

mixtures. Because simultaneous screening, testing, and evaluation of so many chemicals is far beyond

the capabilities of available facilities and resources, EDSTAC suggested that the universe of chemicals

undergo an initial sorting into four categories with recommended action as follows:

1. Chemicals that are unlikely to have endocrine disrupting effects would be placed on hold

initially;

2. Chemicals with insufficient data would initially undergo high throughput pre-screening and tier 1

screening;

3. Chemicals with sufficient data to bypass tier 1 screening would go directly to tier 2 testing; and,

4. Chemicals with sufficient data would go directly to hazard assessment.

The EDSTAC estimated that following the sorting exercise, approximately 62,000 chemicals

would still require screening and/or testing. Therefore, EDSTAC recommended these chemicals should

be prioritized for further evaluation and that the Endocrine Disruptor Screening and Testing Program

should be implemented in a phased manner (i.e., high priority chemicals screened and tested during

Phase 1). The core priority setting process recommended by EDSTAC focuses on giving high priority to

chemicals with widespread exposure at the national level. The EDSTAC also recommended a

nomination process to accommodate chemicals for which exposure is disproportionately high for specific

groups, communities, or ecosystems.

As noted previously, some of the Great Waters pollutants of concern (e.g., PCBs, dioxins) are

already known to possess endocrine disrupting capabilities. These chemicals would most likely be

categorized into group 3 or group 4 using the sorting scheme recommended by EDSTAC. Nevertheless,

at this time, it is uncertain what priority would be given to individual Great Waters pollutants of concern

for further evaluation under the Endocrine Disruptor Screening and Testing Program.
Chapter IV

Science and Tools

Page IV-24 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Chesapeake Bay Toxicity Testing and Biological Community

Assessments

A recent pilot project attempted to integrate an environmental ambient toxicity testing approach

with a biological community assessment approach to determine to what extent toxic pollutants affect fish

populations in Chesapeake Bay. The results are presented as tributary-specific ambient toxicity testing in

the framework of a toxicity risk ranking model developed specifically for contrasting complex

toxicological results with biological indicators of community health. The two tools that were combined

in this project include an ambient toxicity approach which provides a picture of biologically significant

environmental contamination and a toxicological risk ranking method which integrates an array of

toxicological data results into a site-specific “risk score” (Hartwell et al. 1995).

Four tributaries of the Chesapeake Bay were chosen as test sites for this project. Each tributary

represents a watershed impacted by different land uses. The Curtis Creek watershed is dominated by

urban and commercial development and was selected as an example of a polluted area. The Rock Creek

watershed is dominated by urban development but does not have any major industrial areas. Fishing Bay

is located in a lightly developed area and is over 70 percent forest and wetlands. This area is considered

a relatively uncontaminated environment. The Wicomico River watershed is dominated by forest and

agriculture and represents a clean reference area with no direct point source pollution. Fish community

and water column sampling was performed between May to September 1993. For the ambient toxicity

program, a ranking scheme of five components (end-point severity, response proportion, test variability,

site consistency, and number of measured end-points) was developed to evaluate the toxicological results

on a site-by-site basis (Hartwell et al. 1995).

The results indicate that the assays are sensitive enough to identify biologically significant

contamination. Trends between the Index of Biotic Integrity (IBI) scores, which are an expression of the

overall condition of the structure and function of the fish community, and the toxicological risk ranking

scheme exist; however, stronger statistical associations are observed between the risk scores and specific

metrics in the fish community database. As other studies advance, additional sites can be included in the

analyses. As more information is included in the toxicological database, correlations with a variety of

community databases will be possible (Hartwell et al. 1995).

ATSDR PCB/PAH Great Lakes Sensitive Population Studies

The Great Lakes Critical Programs Act, enacted in 1990, required EPA in consultation with the

Agency for Toxic Substances and Disease Registry (ATSDR) to assess the adverse affects of water

pollutants in the Great Lakes. In 1996, EPA and ATSDR published a Report to Congress that

summarized existing research on the human health effects of Great Lakes pollutants. In addition,

ATSDR developed a Great Lakes Health Effects Research Strategy that the agencies used to guide a suite

of new epidemiological studies. In particular, EPA through ATSDR made ten grants to support research

related to potential adverse human health effects from consumption of contaminated Great Lakes fish. 

Eight of the grants supported investigations focusing on susceptible populations (i.e., Native Americans,

sports anglers, the urban poor, pregnant women, and fetuses and nursing infants of mothers who eat

contaminated fish). The ninth and tenth grants supported the development of an interlaboratory quality

assurance and quality control program and the development of more sensitive methods for detecting

contaminants in biological samples (U.S. EPA 1999f).
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-1 Thomas A. Schneider (courtesy Michigan Travel Bureau)

CHAPTER V

NEXT STEPS FOR THE GREAT WATERS PROGRAM

This report describes significant new

scientific and programmatic developments

relevant to the Great Waters program since

the Second Report to Congress (June 1997). 

These developments support and build on the

three broad conclusions presented in the First

and Second Reports to Congress:

• Atmospheric deposition can be a

significant contributor of toxic

chemicals and nitrogen compounds

to the Great Waters. The relative

importance of atmospheric loading

for a particular chemical in a given

waterbody depends on many factors,

including characteristics of the

waterbody, properties of the

chemical, and the kind and amount of

atmospheric or water discharges. 

• A plausible link exists between

emissions into the air of Great

Waters toxic pollutants of concern,

the atmospheric deposition of these

pollutants (and their transformation

products), and the concentrations of

these pollutants found in water,

sediments and biota, especially fish

and shellfish. For mercury, fate and

transport modeling and exposure

assessments predict that the anthropogenic contribution to the total amount of methylmercury in

fish is, in part, the result of anthropogenic mercury releases from industrial and combustion

sources increasing mercury body burdens (i.e., concentrations) in fish. Furthermore, the

consumption of fish is the dominant pathway of exposure to methylmercury for fish-consuming

humans and wildlife. However, what is known about each stage of this process varies with each

pollutant (for instance, the chemical species of the emissions and its transformation in the

atmosphere). 

• Airborne emissions from local as well as distant sources, both within and outside the U.S.,

contribute pollutant loadings to waters through atmospheric deposition. Determining the relative

roles of particular sources contributing to specific waterbodies is complex, requiring careful

monitoring, atmospheric modeling, and other analytical techniques.
Chapter V

Findings, Conclusions, and Recommendations

Page V-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Strategic Themes of EPA’s Great Waters Program

(1) The EPA will continue ongoing efforts to implement

section 112 and other sections of the CAA and use

results from this report in the development of policy that

will reduce emissions of the Great Waters pollutants of

concern.

(2) The EPA recognizes the need for an integrated

multimedia approach to the problem of atmospheric

deposition of pollutants to waterbodies and will continue

to pursue implementation of programs available under

various Federal laws to reduce the human and

environmental exposure to pollutants of concern.

(3) The EPA is committed to supporting research

activities that address the goals of section 112(m) of

the CAA.

As Chapter II showed, there has been

significant progress in environmental research

since the Second Report to Congress,

particularly in monitoring and modeling

pollutant transport and loadings at the regional

and national scale. As a result, spatial and

temporal trends in pollutant emissions,

loadings, and effects are becoming clearer as

the identified research gaps are being

addressed. 

Chapter III described more than 60

relevant programs and activities, ranging in

scale from local to international, many of

which directly or indirectly contribute to

reducing loadings and exposures for many of

the pollutants of concern. Collectively, these

programs and activities show a high level of interagency, intergovernmental, and public-private

cooperation. In addition, those programs led or supported by EPA have advanced the strategic themes

and recommended actions developed in the First and Second Reports to Congress (see text box),

including pursuing integrated multimedia approaches to environmental protection. These programs have

also furthered the Agency’s Clean Air, Clean Water, International, Pollution Prevention, and Sound

Science goals under the Government Performance and Results Act. 

Chapter IV summarized notable developments in science and tools since the Second Report to

Congress. Because of the large scale and technical complexities of the problems, considerable time,

effort, and resources have been expended to develop tools to understand and resolve them. In part

because of the efforts of the Great Waters program, there is now a greater level of coordination among

research agencies and institutions to target areas of critical uncertainty and suspected threats to human

health and the environment. Some of the recently-developed tools and research programs will generate

important new data and findings that will be available for future Great Waters Reports to Congress and

will enable EPA to make further progress in reducing the harmful effects of atmospheric deposition to

the Great Waters. 

Like the Second Report to Congress, the key conclusions of this report and recommendations for

continued or further action are organized by the subject areas EPA is required to assess under the Great

Waters provisions of the CAA, namely the sources and loadings of the pollutants of concern to the Great

Waters, and their environmental and public health effects. In addition, this chapter addresses the

description of any revisions to CAA and other Federal requirements, standards, and limitations, (if such

revisions are necessary), as well as whether the pollutants of concern have caused any exceedances of

water quality or drinking water standards.

In general, deposition rates of the air pollutants of concern to the Great Waters are decreasing or

remaining steady. Also, while we observe a trend toward reduced concentrations of these pollutants in

water and other media for many atmospherically deposited pollutants of concern, this is not the case for

all of them. Potential human health risks are greatest for those individuals who consume fish from

contaminated waterbodies. Some pollutants continue to contribute to significant and widespread

ecological problems in the Great Waters. 
Chapter V

Findings, Conclusions, and Recommendations

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-3

 Substantial uncertainties remain about the extent, sources, fate and effects of atmospheric

deposition. This report supports continued research targeted toward addressing remaining uncertainties

and providing decisionmakers with the tools and information they need to assess potential risks and

determine whether further action is necessary to reduce them. The Agency believes that considerable

continued effort is justified to address critical remaining uncertainties, improve the characterization of

the contribution of atmospherically deposited pollution to the Great Waters, and to further reduce this

pollution.
Chapter V

Findings, Conclusions, and Recommendations

1

 Atmospheric Exchange Over Lakes and Oceans Surfaces (see page IV-13)

Page V-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

V.A POLLUTANT SOURCES

In the past 2 years, new models and model enhancements, tools, and emissions inventories,

including long range transport atmospheric modeling (e.g., RELMAP), source “fingerprinting,” back

trajectory analysis, EPA’s National Toxics Inventory, and the Great Lakes Regional Air Toxics Emission

Inventory, have provided new information to help identify sources of pollutants which are deposited to

waterbodies. Emissions of some Great Waters pollutants of concern have decreased, while others

remained constant or varied. Additional emission reductions are expected to result from continued

implementation of current regulations and nonregulatory programs, as well as development of future

regulations, pollution prevention initiatives, and voluntary actions.

FINDINGS AND CONCLUSIONS

• Emissions and numbers of U.S. anthropogenic sources have declined for mercury, lead,

dioxins and furans, and the banned and restricted use substances. For example, lead

emissions in the Great Lakes region declined at a rate of 6.4 percent per year from 1982 to 1993

reflecting the national decline in lead emissions resulting from the phase-out of leaded gasoline

in automobiles.

• Emissions from U.S. anthropogenic sources for NOx have remained relatively constant. 

For cadmium, emissions in the Great Lakes region have not shown a trend since the 1980s. 

Trends for POM/PAHs are not known. For example, nationwide NOx emissions have

fluctuated around 21 to 23 million metric tons per year from 1988 to 1997.

• The sources of atmospheric deposition vary, depending on the pollutant. As an example,

sources of atmospherically-deposited mercury include emissions from industrial and combustion

sources, emissions from natural sources such as volcanoes, and re-emission from mercurycontaminated soils and water. These sources can be in the U.S. or other countries, and the

mercury emissions can be deposited near the source or transported long distances across

international borders. Some point sources emit significant amounts of reactive chemical forms of

mercury which are deposited locally, near the source of emissions. Determining a more complete

picture of atmospheric deposition to the Great Waters requires ascertaining the contributions of

each of the relevant sources.

• Local sources, including urban areas, can have a large impact on local pollutant deposition

rates. Recent research under the AEOLOS1 project continues to show that the diffuse emissions

of urban areas (i.e., urban plumes) can significantly affect nearby deposition rates. For example,

deposition rates of PCBs and polycyclic aromatic hydrocarbons (PAHs) have been found to be

elevated over southern Lake Michigan near the Chicago urban area. Therefore, estimates of

pollutant loadings and net flux at the waterbody-scale (e.g., for Lake Michigan) may be sensitive

to the placement of monitoring sites.

• Loadings of banned pesticides to the Great Waters are primarily from sources that are

difficult or may not be practical for EPA, States, or tribes in the U.S. to further regulate. 

Although there are no major sources of banned pesticides in the U.S., loadings continue from

remaining consumer stocks, evaporation from soils, resuspension of contaminated sediments, and
Chapter V

Findings, Conclusions, and Recommendations

2

 Regional Langragian Model of Air Pollution

3

 Regional Acid Deposition Model

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-5

airborne transport from other countries. Future reductions must come from clean up of existing

stockpiles and contaminated sites and reductions in airborne pollutants transported from other

countries. Research continues at EPA and other institutions on soil remediation methods that

will reduce emissions of these pollutants from contaminated sites.

• Implementation of existing EPA regulations is expected to further reduce emissions of

mercury, NOx, POMs, dioxins and furans, cadmium, lead, and hexachlorobenzene, and

contribute to declines in deposition of these pollutants. The EPA regulations issued over the

last few years will significantly reduce known sources of these Great Waters pollutants of

concern. For instance, the emission standards and guidelines for municipal waste combustors

and for hazardous/medical/infectious waste incinerators will reduce mercury and dioxin

emissions from these sources by greater than 90 percent from 1990 when fully implemented in

2000 and 2002, respectively. Emission standards for hazardous waste-fired combustors were

issued in 1999 and are expected to be implemented in 2002. This rule will reduce dioxins and

furans by 70 percent, as well as other pollutants such as mercury. In addition EPA’s NOx SIP

call, when implemented, is expected to reduce NOx emissions by about one million metric tons

during the summer ozone season, contributing to a projected decline in NOx emissions through

2005.

• Developments in pollution models and source information are improving our ability to

identify and quantify sources and deposition of pollutants. In recent years, EPA and NOAA

have continued to develop and refine models and source information in order to improve

emissions estimates and understanding of the relative importance of various sources to

atmospheric deposition. For example, the long range atmospheric transport model RELMAP2

was used to estimate domestic and global mercury deposition and RADM3 was used to estimate

coastal NOx deposition. However, there is still a critical need for key inventory information on

the pollutants of concern (e.g., ammonia, speciated data for metals, more accurate data for

pollutants emitted in small quantities, locational data for area and mobile sources) in order to

generate more effective model estimates that can be used in control strategy decisions.

RECOMMENDATIONS FOR CONTINUED AND FURTHER ACTION

• Within any limitations imposed by court rulings, EPA will ensure the timely implementation of

NOx control strategies already put in place, such as the NOx SIP call and emission standards and

guidelines for municipal waste combustors, as well as the Tier 1I tailpipe standards, which are

expected to significantly reduce on-road mobile source NOx emissions throughout the year. The

EPA will proceed with full implementation of the section 126 rule to achieve the required NOx

reductions by May 1, 2003. Finally, EPA will encourage innovative, nonregulatory approaches

to reducing NOx emissions such as "Smart Growth” planning in urban areas and energy

conservation programs.

• The EPA will continue to develop and implement technology-based standards and guidelines

under sections 111, 112, and 129 of the CAA that will achieve further reductions of Great Waters

pollutants of concern. For instance, EPA expects to complete MACT standards mandated by

section 112 for source categories which emit pollutants of concern (e.g., chlorine manufacturing
Chapter V

Findings, Conclusions, and Recommendations

Page V-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

[chlor-alkali plants], coke ovens [pushing, quenching and battery stacks], industrial boilers,

institutional and commercial boilers, iron and steel foundries, and refractory manufacturing) by

2002. Also, EPA expects to complete regulations under section 111 and 129 for commercial and

industrial waste incinerators by November 15, 2000, and for small municipal waste combustors

by 2001. In addition, EPA expects to finalize the list of area source categories by 2003 and

expects to complete regulations by 2004 for the area source categories published in the

integrated urban air toxics strategy on July 19, 1999.

• The EPA expects to complete collection and analysis of information on mercury emissions and

controls for coal-fired utility boilers and issue the regulatory determination for air toxics from

electric utilities by December 15, 2000. 

• Under the residual risk program, EPA will assess risks associated with exposures from emissions

of Great Waters toxic pollutants of concern, using risk, exposure, and other relevant public

health and environmental information developed by EPA offices and its partners. These

assessments will focus on the risk remaining from categories of air toxics sources (or individual

sources within the categories) for which MACT standards have been applied, and include

assessing the public health risk from eating fish contaminated by these sources and risks to

ecosystems. Where analyses indicate unacceptable adverse effects to public health or the

environment from these sources of pollutants, EPA will pursue appropriate actions to reduce

risks.

• The EPA will continue to explore ways to integrate the authorities within single media statutes

and their programs (i.e., CAA, Clean Water Act) in order to support multimedia strategies to

reduce pollutants of concern to the Great Waters. This includes building on recent progress to

increase communication and program coordination between EPA’s Air and Water programs

(e.g., pulp and paper "cluster" rule). For example, EPA's Office of Water and Office of Air and

Radiation (OAR) will consider how to involve the air program in review of TMDLs that list air

sources.

• The EPA will encourage innovation among States to address local air sources of persistent,

bioaccumulative toxics and promote voluntary pollution prevention actions, where appropriate. 

For instance, EPA will document the results of projects under way nationwide to reduce, collect,

and recycle mercury-containing products and disseminate the information broadly.

• The EPA will continue to encourage phase-out and safe disposal of banned and restricted Great

Waters substances (e.g., "clean sweeps” for banned pesticides). The EPA, working with NOAA

and other Federal and State partners, will continue to monitor levels in the environment (e.g.,

fish tissue levels) to verify trends in loadings.

• The EPA expects to complete development of a Mercury Research Strategy in 2000. The

Strategy will describe the key research questions for mercury that EPA plans to address over the

coming 5 years and will identify other technical and scientific issues that are important to the

Agency’s efforts in addressing mercury.

• The EPA expects to finalize in 2000 the Dioxin Reassessment following peer review. This report

will update our scientific understanding of the health risks resulting from exposure to dioxins.

• The EPA will improve the public’s "Right to Know” about certain toxic compounds. The EPA

will implement the rulemaking which added dioxin and other persistent, bioaccumulative, toxic 
Chapter V

Findings, Conclusions, and Recommendations

4 Commission for Environmental Cooperation

5 United Nations Economic Commission for Europe Long Range Transboundary Air Pollution Convention

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-7

chemicals to the Toxic Release Inventory and lowered the reporting threshold for these and other

listed chemicals under the TRI. The EPA also expects to issue to the public by 2001 the first TRI

reports that include these substances.

• The EPA will continue to lead efforts to research viable controls for sources of pollutants of

concern. For example, research will continue on mercury from combustion processes, including

modifying the mixtures and inputs of fuel, and more effective control devices on emitted gases

and particles. This research will also evaluate costs and relative effectiveness of control

options.

• The EPA will continue to provide leadership in reducing transboundary transport of mercury,

DDT, PCBs, chlordane, and other toxic pollutants of concern by achieving assessment and

reduction goals contained in international agreements (e.g., Great Lakes Binational Strategy,

CEC4 North American Regional Action Plans, UN/ECE LRTAP5 Heavy Metals Protocol). The

EPA will support efforts to share technology, information and expertise with other countries on

reducing releases to the environment and on cost-effective alternatives. The EPA will also

continue to provide support to the international negotiations on persistent organic pollutants

under the United Nations Environmental Programme.

• The EPA will continue to pursue international agreements to reduce transboundary NOx,

including negotiating an ozone annex to the US/Canada Air Quality Agreement. 

• The EPA will continue to support joint work with States and industry to fill gaps in source

categories and further refine emission measurement methods and inventories for Great Waters

pollutants of concern (e.g., speciated data on pollutants such as metals and PAHs for the Great

Lakes RAPIDS inventory and for the National Toxics Inventory) so that they can be used

effectively in models being developed. 
Chapter V

Findings, Conclusions, and Recommendations

Page V-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

V.B CONTRIBUTION OF ATMOSPHERIC DEPOSITION TO

POLLUTANT LOADINGS IN THE GREAT WATERS

Research, monitoring, and modeling of pollutant inputs to the Great Waters has continued to

provide important information about loadings. Recent results from available data indicate that

atmospheric inputs of some pollutants of concern are decreasing while others remain constant. However,

there is considerable uncertainty in the data because of limited monitoring, technological barriers, and

variable collection and analytical methods, making it difficult to adequately characterize historical as

well as current conditions and to discern pollution trends. In addition, not all Great Waters waterbodies

or all pollutants of concern have been studied.

FINDINGS AND CONCLUSIONS

• Based on available data, atmospheric deposition of lead, cadmium, POM/PAHs, PCBs, and

some pesticides (e.g., DDT, hexachlorocyclohexanes, dieldrin) to the Great Lakes has

continued to decline in recent years. Similar trends are seen in some other Great Waters.

• Based on available data, atmospheric deposition of nitrogen compounds has remained

relatively unchanged in the Great Waters in recent years. This correlates with a relatively

constant trend in NOx emissions during the same period. Considerable uncertainty exists,

however, concerning dry deposition of nitrogen compounds and wet organic nitrogen deposition.

• Despite recent declines, atmospheric deposition continues to be a significant contributor of

certain pollutants to some Great Waters. For example, one researcher has reported that

atmospheric deposition contributes 70 to 90 percent of the direct lead inputs to the Long Island

Sound. In the Great Lakes, according to another study, the relative contribution of dioxins and

furans from the atmosphere ranges from 5 to 100 percent. Various studies of nitrogen deposition

to Atlantic and Gulf Coast bays and estuaries indicate that 2 to 38 percent of total nitrogen inputs

are attributable to atmospheric deposition. 

• While run-off from fertilizer application, farm animal operations, waste treatment,

industrial effluents, and crop residues continues to be the largest contributor to total

nitrogen loadings, atmospheric inputs of nitrogen compounds to the Great Waters are

much higher than natural rates. Although atmospheric loading rates of inorganic nitrogen

appear to have leveled off, the rates remain many times greater than natural rates and have the

potential, when combined with other loadings such as runoff, to overwhelm the assimilative

capacities of surface waters. Research is ongoing into the lesser known but apparently important

forms of nitrogen deposition (e.g., dry deposition, organic nitrogen). In addition, nitrogen

saturation of upland forests, grasslands, and agricultural fields may occur in some areas and

could significantly increase the rate of nitrogen transport from upland watersheds to coastal

waters in the future, even if atmospheric loading rates remain constant. 

• Although considerable uncertainty remains, EPA’s 1997 Mercury Study Report to Congress

estimates, based on a modeling analysis, that one-third (52 tons) of the anthropogenic

mercury emitted annually in the U.S. is deposited in the continental U.S., along with an

estimated 35 tons from the global reservoir (which includes U.S. anthropogenic as well as

natural and re-emitted mercury emissions). These results to date suggest that the remaining

two-thirds (~ 107 tons) of annual U.S. anthropogenic emissions are transported beyond U.S.

borders, where they diffuse into the global reservoir. As U.S. anthropogenic emissions are
Chapter V

Findings, Conclusions, and Recommendations

6

 Hybrid single particle Lagrangian integrated trajectory/transfer coefficient (see page II-31)

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-9

reduced, the relative contribution from the global pool will be even larger, particularly if similar

control actions are not undertaken in other countries. Studies of mercury deposition to certain

Great Waters indicate that atmospheric deposition contributes between 10 and 85 percent of the

total mercury loadings to these waterbodies. Because a deposition monitoring network for

mercury has only recently been established, there are not yet sufficient data to determine

monitored trends in mercury deposition levels.

• Certain banned and restricted use pesticides are projected to be the first pollutants of

concern to be reduced to concentrations below current atmospheric detection limits in the

Great Lakes atmosphere, indicating that risk management strategies are having the

intended impact. Based on recent academic research on atmospheric pollutant concentrations in

the Great Lakes region, DDT and DDE, followed by dieldrin and chlordane, are estimated to fall

below current detection limits in the atmosphere between 2010 and 2020. Hexachlorocyclohexane and hexachlorobenzene are projected to fall below current detection limits in the

atmosphere over the Great Lakes by 2030 and 2060, respectively. These estimates assume

current rates of long-range transport of these pollutants into the region. Because of their

persistence, it should be noted that elimination of these pollutants in the atmosphere does not

mean that concentrations would be eliminated in deposited media (e.g., sediments) by these

dates. However, these estimates indicate that reduction strategies in the Great Lakes, along with

the original bans or restrictions on the use of these substances, are having the intended effect.

• Significant progress has been made involving monitoring and modeling research focused on

the factors that affect pollutant fate and transport in regional-scale air masses and in

watersheds. Since the Second Report to Congress, there have been significant advances in

monitoring and modeling of pollutant transport and loadings at both regional and national scales. 

Recent accomplishments include data collection and analysis of results from the AEOLOS

project, establishment of the Mercury Deposition Network (part of the National Atmospheric

Deposition Program), applications of the HYSPLIT/TRANSCO6 computer program,

development of the Models-3 community multiscale air quality modeling system, monitoring

established by the South Florida Mercury Science Program, and progress on the Lake Michigan

Mass Balance Study. The Integrated Atmospheric Deposition Network, an international effort to

monitor air toxics deposition, has produced a long-term data set on loadings trends in the Great

Lakes. As in past years, much of the research on modeling of pollutant loading rates has focused

on mechanisms of direct pollutant deposition to surface waters (e.g., pollutant exchange

mechanisms, surface microlayers). However, a growing area of research addresses factors, such

as the effects of land cover, weather events, that affect the fate and transport of pollutants in

watersheds and tributaries. For example, a variety of factors influence how much deposited

mercury will be methylated and incorporated into the food chain, including lake and watershed

characteristics, water chemistry, and the length of the food chain.

• Long-range transport from other U.S. regions or other countries is estimated to contribute

significantly to atmospheric loadings of pollutants of concern to the Great Waters. As

stated above, EPA estimates that 35 tons of mercury from the global reservoir (derived from both

foreign and U.S. sources) are deposited annually in the U.S., representing 40 percent of the total

mercury deposition to the U.S. In a modeling study conducted in the northeastern U.S., sources

from outside the study region contributed 30 percent of the mercury loadings within the study

region and the global reservoir contributed approximately 20 percent. Another modeling study
Chapter V

Findings, Conclusions, and Recommendations

Page V-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

conducted to assess sources of dioxin to the Great Lakes basin shows that sources as far as

central Canada may influence deposition of dioxin to the lakes.

RECOMMENDATIONS FOR CONTINUED AND FURTHER ACTION

• By summer 2000, EPA expects to develop a work plan to assess atmospheric deposition on a

regional basis. This work plan would include: targeting State-identified impaired waterbodies;

examining what rules or activities are in place that address impairment caused by atmospheric

deposition; and, determining what, if any, additional actions are necessary to address

impairment caused by atmospheric deposition. In addition, EPA expects to revise this work plan

every two years based on updated scientific information and stakeholder input. 

• The EPA will work with national deposition monitoring programs, States, National Estuary

Programs, NOAA, and other research institutions to establish monitoring sites in coastal areas

where they do not already exist, as appropriate. The EPA will encourage expansion of the

National Atmospheric Deposition Program’s Mercury Deposition Network, the continuation of

other toxics deposition monitoring networks, such as the Integrated Atmospheric Deposition

Network, and the development of a national air toxics monitoring network to support assessment

of the contribution of long-range transport to deposition of Great Waters pollutants of concern

in the U.S. and to evaluate the impact of urban sources.

• The EPA will encourage the use of standard monitoring methods to enable comparison of data

and trends analysis. Where methods for measuring atmospheric deposition for pollutants of

concern do not exist, EPA, working with NOAA and other Federal colleagues and key

institutions such as the National Atmospheric Deposition Program, will continue to lead and

support efforts to develop technology and establish standard methods (e.g., POM and PAH,

mercury species, dissolved organic nitrogen, and dry deposition of pollutants).

• The EPA will continue to work with NOAA and other scientific partners to develop, refine, and

validate modeling tools that help us to better understand the pathways of the pollutants of

concern -- from emissions to transport to deposition to fate to environmental and human health

effects. 

• The EPA will work with NOAA and other agencies to better quantify the indirect loadings of

atmospheric deposition to the Great Waters through the development of tools that can quantify

watershed transport of pollutants of concern.

• The EPA will continue to support international efforts to quantify the transboundary

contributions of pollutants of concern, such as the Commission for Environmental Cooperation

efforts to assess continental pollutant pathways and the Binational Strategy challenge to assess

global sources of pollutants to the Great Lakes. 
Chapter V

Findings, Conclusions, and Recommendations

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-11

V.C ENVIRONMENTAL AND PUBLIC HEALTH EFFECTS

Because the Second Report to Congress discussed potential adverse human health and

environmental effects from exposure to the Great Waters pollutants of concern in considerable detail, this

report focused on observed changes in exposure levels and trends in observed effects, to the extent that

data were available. Scientific research has continued to improve our understanding of the toxic effects

of the pollutants of concern, including endocrine disruption. Concentrations of some of the pollutants of

concern in the environment have decreased in recent years, while others have remained constant or are

variable. At some locations, mercury concentrations are at levels sufficient to produce adverse health

effects for certain groups consuming large amounts of contaminated fish (e.g., young children, pregnant

women and their developing fetuses, women of child-bearing age, and populations that subsist on fish),

as well as ecological risks.

FINDINGS AND CONCLUSIONS

• Available monitoring data indicate that concentrations of dioxin/furans and PCBs, in the

sediment, water, and biota of several of the Great Waters appear to be declining, while

concentrations of lead, cadmium, mercury, and POM/PAH are too variable for a trend to

be discerned. For example, concentrations of PCBs in biota have continued to decline in the

Great Lakes, with PCB concentrations in St. Lawrence River fish decreasing by a factor of 30

since 1975. Trends in concentrations of lead, cadmium, mercury, and POM/PAH were more

variable or could not be discerned from the available data. Although recent research did not

address contamination levels of all pollutants of concern, no identified studies indicated

increasing levels of pollutants of concern in the Great Waters.

• Available monitoring data indicate that various pollutant concentrations in sediments,

water, and/or biota of the Great Waters have been detected at levels resulting in exposures

that are high enough to cause adverse environmental effects. As was reported in the Second

Report to Congress, a number of regional- and national-scale assessment and monitoring

programs (e.g., the National Sediment Quality Survey, Benthic Surveillance Project) suggest that

the ecological health of many Great Waters are impaired by pollution that is partially attributable

to atmospheric deposition. Further evidence of ecological impairment includes research results

indicating that up to 30 percent of the loons in the northeastern U.S. have mercury levels

sufficiently high to cause adverse effects. 

• Excess nitrogen loadings can cause algal blooms (including harmful algal blooms), shifts in

aquatic vegetation, fish declines and kills, and shellfish bed losses. The NOAA Estuarine

Eutrophication Surveys indicate that the adverse effects of excess nitrogen loadings are currently

evident to some degree in approximately 89 percent of the U.S. coastal Great Waters. Numerous

studies on individual estuaries have estimated that 20 to 40 percent of total loading of nitrogen

compounds can come from atmospheric deposition, with the rest of the loading originating from

water discharges or land-use activities. 

• Fish consumption is the primary pathway of human exposure to mercury, is an important

pathway for dioxin and PCBs, and may be an important pathway for various other Great

Waters toxic pollutants. While such exposures may not be of concern for most of the

general population, for certain pollutants and contamination situations, certain groups

such as young children, developing fetuses, subsistence fish-eating populations, and others

who consume large amounts of contaminated fish, may be at risk. For mercury specifically,
Chapter V

Findings, Conclusions, and Recommendations

Page V-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

exposures do not appear to pose a health risk to people consuming average amounts of fish , but

sensitive sub-populations (e.g., young children, and pregnant women and their developing

fetuses) with higher than typical fish consumption are at risk. Also at risk are subsistence fisheating populations who consume large amounts of fish. The extent of risk for these groups

depends on the amount of fish consumed and the mercury concentrations present in the fish. 

• The role of transformation processes on certain pollutants once they are emitted is an

important phenomenon which can increase their toxicity and persistence in the

environment. For instance, mercury emitted by industrial or combustion processes becomes

much more toxic and biologically available after it is deposited in the environment and

transformed to methylmercury. Another example is the transformation of alpha- and gammahexachlorocyclohexane to beta-hexachlorocyclohexane (HCH). More research on these

transformation processes is needed to better understand their role and to develop appropriate

responses.

• Evidence for adverse effects from endocrine disrupting chemicals continues to be found.

Recent research provides additional evidence of the adverse effects of endocrine disruptors on

both wildlife and humans, and at least two Great Waters pollutants of concern (i.e., PCBs and

dioxins) are known to possess endocrine disrupting capabilities. The EPA has worked with

various governmental and non-governmental interests to develop a screening and testing

approach for systematically identifying endocrine disruptors and quantifying their effects. 

RECOMMENDATIONS FOR CONTINUED AND FURTHER ACTION

• The EPA will continue to support the development and validation of modeling tools which

address the transport and fate of pollutants in ecosystems and characterize risk, such as the

Total Risk Integrated Methodology. The EPA will also continue to support the improvements in

inventories, monitoring data, and human and environmental effects information necessary to

effectively apply these tools. 

• In conjunction with its related efforts on persistent, bioaccumulative, toxic pollutants (e.g., the

Great Lakes Binational Strategy and the Persistent, Bioaccumulative Toxics Initiative), EPA will

identify and evaluate additional pollutants which may be of concern to the Great Waters.

• The EPA expects to explore one or more community-based pilot projects to develop and examine

methodologies for characterizing local risks and to work with stakeholders on risk reduction

strategies. In conducting such pilot studies, the EPA will consider cumulative risks presented by

exposures to air toxics emissions in the aggregate, including exposures through noninhalation

pathways, such as consumption of contaminated fish from waterbodies affected by deposition of

air toxics.

• The EPA will continue to support work to quantify the ecological effects of atmospheric

deposition. For instance, EPA will support research to answer critical questions related to the

assessment of pollutant exposures for varying life stages and for species at various levels of the

food chain.

• The EPA expects to complete, by December 2000, the new Water Quality Criterion Methodology

for Human Health to better reflect pollutants that bioaccumulate and the Nation’s changing fish

consumption patterns. 
Chapter V

Findings, Conclusions, and Recommendations

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-13

• The EPA will work with NOAA, US Fish and Wildlife Service, other Federal agencies, States,

and tribes to expand the geographic coverage and consistency of waterbody monitoring to

enable more accurate characterizations of the extent of contamination and ecosystem effects due

to atmospheric deposition of Great Waters pollutants of concern. In addition, EPA will increase

efforts to implement nationally-consistent methods and protocols for assessing contaminants in

fish and wildlife and establishing consumption advisories. 

• The EPA, working with States, tribes, and other relevant partners, will continue to support

efforts to improve awareness and understanding of fish consumption advisories among

populations most at risk to exposure to the Great Water pollutants of concern.

• The EPA will provide leadership for efforts to examine the mechanisms of action and resulting

effects (e.g., reproductive failure, death, species diversity, ecological sustainability) of exposures

to realistic concentrations of common contaminants, alone and in combination. The EPA will

also lead the development of predictive models to assess likely effects of single and multiple

stressors and alternative environmental conditions on individual aquatic plants and animals,

populations, communities, and ecosystems.

• The EPA will continue to pursue as a priority its research plan for endocrine disruptors,

covering ten broad categories of research needs: basic research, biomarkers, database

development, exposure determination, exposure follow-up, mixtures, multidisciplinary studies,

risk assessment methods, hazard identification, and sentinel species. 

• The EPA will accelerate work to better quantify the water quality benefits of air pollution

controls in order to provide decisionmakers with critical information on environmental

strategies to reduce the extent of contamination by Great Waters pollutants of concern. By 2001,

EPA expects to conclude a pilot study of the economic benefits of reducing nitrogen deposition in

a particular estuary, developing methodologies that could be applied to other waterbodies.
Chapter V

Findings, Conclusions, and Recommendations

Page V-14 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

V.D EXCEEDANCES OF WATER QUALITY OR DRINKING WATER

STANDARDS

Atmospheric deposition and other inputs of pollutants of concern to the Great Waters can result

in exceedances of drinking water standards and surface water quality guidance and criteria, posing

threats to human health and the environment. Recent data indicate that water quality standards in place

for drinking water supplies in the Great Waters are not being exceeded for the pollutants of concern;

however, surface water quality guidance and criteria are being exceeded in some of the Great Waters.

FINDINGS AND CONCLUSIONS

• The pollutants of concern cause no exceedances of water quality standards in place for

drinking water supplies in the Great Waters. Pollutant levels in both the Great Lakes and

Lake Champlain are below primary drinking water standards and other thresholds of water

quality. Data indicate that most of the Great Lakes nearshore waters can be used as a source of

drinking water with normal treatment. Similarly, Lake Champlain was not associated with any

violations of standards in place for drinking water supplies due to Great Waters pollutants of

concern from 1986 to 1995. Further reductions in pollutant concentrations may reduce the cost

of drinking water treatment in some areas.

• Primarily because of contamination with metals and nutrients from a variety of sources,

some of which are atmospheric, approximately 40 percent of the Nation’s surveyed rivers,

lakes, and estuaries have been found to have contaminant levels exceeding water quality

criteria and, therefore, discourage basic uses, such as fishing and swimming. In lakes and

rivers, nutrients and metals are the most widespread pollutants, and agriculture is the most

common source; however, atmospheric deposition has also been identified as a source. In

estuaries, nutrients are the most widespread pollutants with industrial point dischargers, urban

runoff, and storm sewers identified as the most common pollutant sources. Atmospheric

deposition has also been identified as a significant source of nitrogen loadings, directly to the

water surface and indirectly via runoff, to most coastal waters where measurements have been

made.

• While the Great Lakes generally are safe for swimming and other recreation, virtually all

of the surveyed shoreline area shows unfavorable conditions for supporting aquatic life and

is impacted by toxic organic chemicals that appear in fish tissue samples at much higher

concentrations than in water samples. This is partially due to persistent toxic pollutant

burdens, such as PCBs and PAHs, in the food web. Several of the Great Lakes States identified

air pollution among other sources as contributing to impaired water quality. 

RECOMMENDATIONS FOR CONTINUED AND FURTHER ACTION

• The EPA expects to complete the development of national water quality criteria for nutrients for

lakes, reservoirs, rivers, streams, estuaries, and coastal waters. This includes developing

waterbody-specific guidance manuals to help State and tribal agencies: (1) classify and assess

their waters in terms of nutrient condition; (2) develop region-specific water quality standards;

and (3) plan management responses to nutrient pollution. Where sufficient data are available,

EPA also expects to develop specific target ranges for total nutrient loads that States can use in

the development of their standards.
Chapter V

Findings, Conclusions, and Recommendations

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-15

• The EPA expects to complete a pilot project to demonstrate total maximum daily load allocations

for two waterbodies receiving mercury from atmospheric deposition. This pilot project will

evaluate the integration of air and water program technical tools and authorities, and will

examine emission reduction options. The EPA will also work with States that have identified

waterbodies whose impairment may be the result of atmospheric deposition to develop tools to

assist in establishing TMDLs that account for air sources. For example, based on the outcome

of the pilot project, EPA will explore the possibility of providing States with modeled regional

baseline and projected deposition estimates for several Great Waters pollutants of concern. 

• The EPA, in partnership with the Chesapeake Bay watershed States, will account for nitrogen

deposition as a part of an effort to improve water quality in the Bay and its tributaries. The

Chesapeake Bay partners have committed to working to integrate a cooperative, statutory

program so that these waters could be removed from the list of impaired waters by 2010.

• The EPA, working with the Great Lakes States, will ensure implementation of the Great Lakes

Water Quality Guidance.

• The EPA will continue to work with its Federal agency partners such as NOAA, and with States,

tribes, and local agencies to improve understanding of the relationship and relative contribution

of atmospheric deposition and water pollution. The EPA expects to develop guidance to assist

National Estuary Programs, States, tribes and local organizations, among others, to evaluate the

role of air deposition in assessing water quality. 
Chapter V

Findings, Conclusions, and Recommendations

Page V-16 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

V.E SUMMARY AND KEY RECOMMENDATIONS

The EPA expects that the many ongoing and scheduled future regulatory and voluntary programs

and activities, many of which are described in this report, will further reduce the impact of air deposition

of pollutants of concern on the Great Waters. These include, but are not limited to:

• Establishing remaining MACT and section 112(c)(6) standards for sources emitting Great Waters

pollutants of concern;

• Implementing EPA’s strategy for the Residual Risk program, which assesses the risk remaining

from MACT source categories (including those emitting Great Waters pollutants of concern),

and issuing additional standards, as appropriate, within the required 8 years of the MACT

standard being promulgated for the source category;

• Implementing programs to control NOx, such as regional strategies to reduce NOx emissions (e.g.,

the NOx SIP call and the rulemaking by EPA in response to States’ petitions under CAA section

126), Tier II/Gasoline sulfur rules for cars, and emission standards and guidelines for municipal

waste combustors, as well as encouraging voluntary approaches to reduce these emissions;

• With NOAA and other Federal agency partners, completing the strategy described in the Clean

Water Action Plan issued in 1998, which addresses remaining obstacles to establishing “fishable

and swimmable waters for all Americans”; and,

• Completing and implementing national multimedia action plans for persistent, bioaccumulative

toxics (PBT) under the Agency’s PBT Initiative.

Development and implementation of these and other programs and initiatives described in this

report should not require revisions to requirements, standards, and limitations pursuant to the CAA and

other Federal laws. Consequently, EPA expects that these programs should help to assure protection of

human health and the environment from atmospheric deposition to the Great Waters. However, in order

to ensure continued progress in reducing sources and loadings of atmospheric deposition to the Great

Waters, and to further reduce the environmental and public health effects, EPA will:

• Continue to support the maintenance and expansion of efforts to monitor Great Waters pollutants

of concern in order to evaluate the relative contributions of local, regional, and long-range

transport to deposition in the U.S., as well as natural versus human-made sources;

• Continue to develop and implement regulations and pollution prevention programs regionally

and nationally, including multimedia programs, in order to reduce the release and impact of

sources of Great Waters pollutants of concern within the U.S.;

• For Great Waters pollutants not emitted by U.S. sources, work within international frameworks

to reduce sources of these pollutants;

• Support model development and research that establish and, if possible, quantify the linkages

from emissions to atmospheric deposition to waterbody loadings to adverse public health and the

environmental effects of Great Waters pollutants of concern in order to enable effective risk

management decisions;
Chapter V

Findings, Conclusions, and Recommendations

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page V-17

• Encourage and support the establishment of common baselines and measures of progress in order

to better assess trends and health of Great Waters and other waterbodies affected by atmospheric

deposition; and,

• Work to increase public awareness of risks of exposure to Great Waters pollutants of concern.

The EPA is committed to continuing to address air deposition of pollutants into the Nation’s

waters as a priority matter. To that end, and to assure continued coordination of the many related tasks

involved and outlined in this report, EPA will develop a detailed biennial work plan for implementation

actions beginning this year and updated every two years. As EPA develops and implements plans,

programs and initiatives with NOAA and its other Federal, State, tribal, industry and community

partners, we expect to make significant, measurable progress toward our goal of assuring the protection

of human health and the environment from adverse effects attributable to atmospheric deposition of

pollution to the Great Waters. 
Errata

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page 1

ERRATA

Page II-7, Table II-1, Rows 8 and 12:

“Chlor-alkali” row (Row 8) should be removed because it is a duplicate with Row 5, “Chlor-alkali

Production.” “Others (<1 percent each)” row (Row 12) should be revised to read 10 tons/year and 6

percent. The corrected table is included below.

Table II-1

National Anthropogenic Mercury Air Emissions

(Based on 1994-1995 Inventory; U.S. EPA 1997e)

Source Category

1994-1995

Anthropogenic Air

Emissions (tons/year)

Percent Contribution to

Total U.S. Anthropogenic

Air Emissions

Utility boilers: coal combustion, oil, and natural gas 52 33

Municipal waste combustion 30 19

Commercial/industrial boilers: coal and oil 28 18

Medical waste incineration 16 10

Chlor-alkali production 7 4

Hazardous waste combustors 7 4

Portland cement, excluding hazardous waste-fired 5 3

Residential boilers: oil and coal 4 2

Pulp and paper manufacturing 2 1

Others (<1percent each) a 10 6

Total U.S. Anthropogenic Mercury Air Emissions 158b,c 100b,c

a

 A list of the source categories that contribute less than 1 percent to total U.S. emissions is provided in Appendix B.

b

 This value represents anthropogenic mercury air emissions in the U.S. only.

c

 Values do not add exactly due to rounding.

Page II-51, Paragraph 3, Sentences 4 and 5:

Replace original sentences with revised sentences provided below. Also, one new reference should be

added, and one reference should be revised.

Original Text: “It should be noted, however, that ADN accounts for roughly only 1 percent of nitrogen

loadings in the Mississippi River basin, which has highly diverse sources of

anthropogenic nitrogen (Goolsby et al. 1998, as cited by Paerl 1999). The ADN is also
Errata

Page 2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

likely to be a relatively less important contributor to nitrogen loadings in Pacific coast

Great Waters than is the case in the east and Gulf coast areas, due to the prevailing

westerly winds over Pacific coastal waters and their watersheds, originating from

unpolluted ocean areas.” 

Revised Text: “In the Mississippi River basin, ADN accounts for at least 10 percent of nitrogen

loadings in the Mississippi River basin, which has highly diverse sources of

anthropogenic nitrogen (Goolsby et al. 1999; Alexander et al. 2000). The ADN is likely

to be a relatively less important contributor to nitrogen loadings in Pacific coast Great

Waters than is the case in the east and Gulf coast areas, due to the prevailing westerly

winds over Pacific coastal waters and their watersheds, originating from unpolluted

ocean areas.” 

New Reference:

Alexander, R.B., R.A. Smith, and G.E. Schwarz. 2000. Effects of stream channel size on the delivery of

nitrogen to the Gulf of Mexico. Nature. 403: 758-761. 

Revised Reference:

Goolsby, D.A., W.A. Battaglin, G.B. Lawrence, R.S. Artz, B.T. Aulenbach, R.P. Hooper, D.R. Kenney,

and G.J. Stensland. 1999. Flux and sources of nutrients in the Mississippi-Atchafalaya River Basin.

Topic 3 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico: NOAA Coastal Ocean

Program, Decision Analysis Series No. 17. 
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-1

REFERENCES

Aigner, E.J., Leone, A.D., and R.L. Falconer. 1998. Concentrations and enantiomeric ratios of

organochlorine pesticides in soils from the U.S. corn belt. Environ. Sci. Technol. 32(9):1162-1168.

Allen, N.S., and A.E. Hershey. 1996. Seasonal changes in chlorophyll a response to nutrient

amendments in a North Shore tributary of Lake Superior. J. N. Am. Benthol. Soc. 15(2):170-178.

Aneja, V.P., G.C. Murray, and J. Southerland. 1998. Atmospheric Nitrogen Compounds: Emissions,

Transport, Transformation, Deposition, and Assessment. EM (A&WMA). April 1998. pp. 22-25.

ASA. 1996. Hydrodynamic and Water Quality Modeling of Lake Champlain. Applied Science

Associates, Inc. Lake Champlain Basin Program Technical Report No. 19. September 1996.

Biegalski, S.R., S. Landsberger, and R.M. Hoff. 1998. Source-receptor modeling using trace metals in

aerosols collected at three rural Canadian Great Lakes sampling stations. Journal of the Air and Waste

Management Association. 48(3): 227-237.

Bowersox, Van C. 1998. Personal communication with ICF Inc. on December 9, 1998.

Boynton, W.R., H.J. Garber, R. Summers, and W. M. Kemp. 1995. Inputs, transformations, and

transport of nitrogen and phosphorous in Chesapeake Bay and selected tributaries. Estuaries. 18: 285-

314.

Brazner, J., and W. DeVita. 1998. PCBs, DDE, and mercury in young-of-the-year littoral fishes from

Green Bay, Lake Michigan. J. Great Lakes Res. 24(1):83-92.

Brock, D.A., J. Matsumoto, and N. Boyd. 1995. A nitrogen budget for the Guadalupe Estuary, Texas,

over a range of freshwater inflow. Contr. In Marine. Sci.

Browner, Carol M. 1998. Reply letter to Rought Reigart, Chair, Children’s Health Protection Advisory

Committee.

Buck, G.M., L.E. Sever, P. Mendola, M. Zielezny, and J.E. Vena. 1997. Consumption of contaminated

sport fish from Lake Ontario and time-to-pregnancy. Am. J. Epidemiol. 146(11):949-954. 

Burger, J. 1997. Heavy metals in the eggs and muscle of horseshoe crabs (Limulus polyphemus) from

Delaware Bay. Environ. Monit. Assess. 46:279-287.

Burke, J., M. Hoyer, G. Keeler, and T. Scherbatskoy. 1995. Wet deposition of mercury and ambient

mercury concentrations at a site in the Lake Champlain Basin. Water, Air, and Soil Pollution. 80: 353-

362.

Buttner, J.K. 1997. First Nation people and Great Lakes aquaculture. Aquaculture Magazine. 

January/February 1997. pp. 27-40.

Cantillo, A.Y., G.G. Lauenstein, and T.P. O’Connor. 1997. Mollusc and sediment contaminant levels

and trends in south Florida coastal waters. Marine Pollut. Bull. 34(7):511-521.
References

Page R-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Cantillo, A.Y., G.G. Lauenstein, and T.P. O’Connor. 1998. Status and trends of contaminant levels in

biota and sediments of the Chesapeake Bay. Regional Reports Series 1. National Oceanic and

Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science,

Center for Coastal Monitoring and Assessment, National Status and Trends Program for Marine

Environmental Quality. 

Carpi, A., and S.E. Lindberg. 1997. Sunlight-mediated emission of elemental mercury from soil

amended with municipal sewage sludge. Environ. Sci. Technol. 31(7): 2085-2091.

Carr, R.S., E.R. Long, H.L. Windom, D.C. Chapman, G. Thursdy, G.M. Sloane, and D.A. Wolfe. 1996. 

Sediment quality assessment studies of Tampa Bay, Florida. Environ. Toxicol. Chem. 15(7):1218-1231.

Chesapeake Bay Program. 1999a. Chesapeake Bay Basin Toxics Loading and Release Inventory. May

1999. www.chesapeakebay.net.

Chesapeake Bay Program. 1999b. www.chesapeakebay.net/indicatr/measure/nnriver.htm. April 8,

1999.

Chesapeake Bay Program. 1998a. www.chesapeakebay.net/bayprogram/news/1997/air.htm. September

3, 1998.

Chesapeake Bay Program. 1998b. www.chesapeakebay.net/bayprogram/news/1997/prform.htm. 

November 2, 1998.

Chesapeake Bay Program. 1998c. www.chesapeakebay.net/bayprogram/news/1997/toxics.htm. 

November 2, 1998. 

Chesapeake Bay Program. 1998d. www.chesapeakebay.net/bayprogram/overview.htm. September 3,

1998.

Chesapeake Bay Program. 1994. Chesapeake Bay Basin Toxics Loading and Release Inventory: 

Basinwide toxics reduction strategy commitment report. March 1994. CBP/TRS102/94.

Chesapeake Bay Program. 1992. Submerged Aquatic Vegetation Habitat Requirements and Restoration

Targets: A Technical Synthesis. CBP/TRS 83/92.

Chillrud, S.N., R.F. Bopp, H.J. Simpson, J.M. Ross, E.L. Shuster, D.A. Chaky, D.C. Walsh, C.C. Choy,

L. Tolley, and A. Yarme. 1999. Twentieth century atmospheric metal fluxes into Central Park Lake,

New York City. Environ. Sci. Technol. 33(5): 657-662.

Chimka, C.T., J.N. Galloway, and B.J. Cosby. 1997. Ammonia and the Chesapeake Bay Airshed. 

Chesapeake Bay Program Scientific and Technical Advisory Committee, Publication No. 97-1.

Christensen, E.R., A.L. Irwan, A.A. Razak, P. Rachdawong, and J.F. Karls. 1997. Sources of polycyclic

aromatic hydrocarbons in sediments of the Kinnickinnic River, Wisconsin. J. Great Lakes Res. 

23(1):61-73.

Cochran, J.K., D.J. Hirschberg, J. Wang, and C. Dere. 1998. Atmospheric deposition of metals to

coastal waters (Long Island Sound, New York U.S.A.): Evidence from saltmarsh deposits. Estuarine,

Coastal and Shelf Science. 46:503-522.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-3

Cohen, M., B. Commoner, H. Eisl, P. Bartlett, A. Dickar, C. Hill, J. Quigley, and J. Rosenthal. 1995. 

Quantitative estimation of the entry of dioxins, furans and hexachlorobenzene into the Great Lakes from

airborne and waterborne sources. May 1995.

Cole, D.C., J. Kearney, J.J. Ryan, and A.P. Gilman. 1997. Plasma levels and profiles of dioxin and

dioxin-like compounds in Ontario Great Lakes anglers. Chemosphere. 34(5-7):1401-1409.

Commission for Environmental Cooperation. 1998. www.cec.org/jpac. October 29, 1998.

Cortes, D.R., Basu, I., Sweet, C.W., Brice, K.A., Hoff, R.M., and R.A. Hites. 1998. Temporal trends in

gas-phase concentrations of chlorinated pesticides measured at the shores of the Great Lakes. Environ.

Sci. Technol. 32(13):1920-1927.

Dennis, R.L. 1999. Personal Communication. Memorandum to Dale Evarts, EPA OAQPS, on the

internal review of the second draft of the 3rd Great Waters Report to Congress. 

Dennis, R.L. 1997. Using the Regional Acid Deposition Model to Determine the Nitrogen Deposition

Airshed of the Chesapeake Bay Watershed. In: Baker, J.L. ed., Atmospheric Deposition of

Contaminants to the Great Lakes and Coastal Waters. Society of Environmental Toxicology and

Chemistry, Pensacola, FL. pp. 393-413.

Dixon, L.K., S. Murray, J.S. Perry, P.J. Minnotti, M.S. Henry, and R.H. Pierce. 1996. Assessment of

bulk atmospheric deposition to the Tampa Bay watershed. Report submitted to the Tampa Bay National

Estuary Program by Mott Marine Laboratory. September 25, 1996.

Dvonch, J.T., J.R. Graney, F.J. Marsik, G.J. Keeler, and R.K. Stevens. 1998. An investigation of sourcereceptor relationships for mercury in south Florida using event precipitation data. Sci. Tot. Environ. 

213: 95-108.

Dykstra, C.R., M.W. Meyer, D.K. Warnke, W.H. Karasov, D.E. Andersen, W.W. Bowerman IV, and J.P.

Giesy. 1998. Low reproductive rates of Lake Superior bald eagles: Low food delivery rates or

environmental contaminants? J. Great Lakes Res. 24(1):32-44.

Eby, L.A., C.A. Stow, R.J. Hesselberg, and J.F. Kitchell. 1997. Modeling changes in growth and diet on

polychlorinated biphenyl bioaccumulation in Coregonus hoyi. Ecological Applications. 7(3):981-990. 

Eisenreich, S.J., and W.M.J. Stachan. 1992. Estimating atmospheric deposition of toxic substances to

the Great Lakes - An update. Report on a workshop held at the Canada Centre for Inland Waters;

January 31-February 2, 1992; Burlington, Ontario. Sponsored by the Great Lakes Protection Fund and

Environment Canada.

Engstrom, D.R., and E.B. Swain. 1997. Recent declines in atmospheric mercury deposition in the upper

Midwest. Environ. Sci. Technol. 31:960-967.

Eskin, R.A., K.H. Rowland, and D.Y. Alegre. 1996. Contaminants in Chesapeake Bay sediments 1984-

1991. Printed by U.S. EPA for the Chesapeake Bay Program. May 1996.

Evers, D.C. J.D. Kaplan, M.W. Myer, P.S. Reaman, W.E. Braselton, A. Major, N. Burgess, and A.M.

Scheuhammer. 1998a. Geographic trend in mercury measured in common loon feathers and blood. 

Environ. Toxicol. Chem. 17:173-183.
References

Page R-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Evers, D. 1998b. Assessing availability and risk of methylmercury to the common loon in New

Hampshire and Vermont. A preliminary report. Submitted to U.S. EPA, Office of Air Quality planning

and Standards, December 3, 1998.

Firestone, D., Fehringer, N.V., Walters, S.M., Kozara, R.J., Ayres, R.J., Ogger, J.D., Schneider, L.F.,

Glidden, R.M., Ahlrep, J.R., Brown, P.J., Ford, S.E., Davy, R.A., Gulick, D.J., McCullough, B.H., Sittig,

R.A., Smith, P.V., Syvertson, C.N., and M.R. Barber. 1996. TCDD residues in fish and shellfish from

U.S. waterways. Journal of AOAC International. 79(5):1174-1183. 

Fisher, D., and M. Oppenheimer. 1991. Atmospheric nitrogen deposition and the Chesapeake Bay

estuary. Ambio. 20(3-4): 102-108. As cited in: Cassie, Galloway, and Cosby (1997).

Fitzgerald, W.F. 1998. Mercury emissions and cycling in the coastal zone: A multimedia approach. 

Final report submitted to U.S. EPA, Office of Air Quality Planning and Standards, June 30, 1998.

Florida Department of Environmental Protection (FDEP). 1996. The South Florida Mercury Science

Program. Florida Department of Environmental Protection, Office of Mercury Contamination. 

Tallahassee, FL.

Franz, T.P., S.J. Eisenreich, and T.M. Holsen. 1998. Dry deposition of particulate polychlorinated

biphenyls and polycyclic aromatic hydrocarbons to Lake Michigan. Environ. Sci. Technol. 32: 3681-

3688.

Froese, K.L., D.A. Verbrugge, S.A. Snyder, F. Tilton, M. Tuchman, A. Ostaszewski, and J.P. Giesy. 

1997. PCBs in the Detroit River water column. J. Great Lakes Res. 23(4):440-449.

Gerstenberger, S.L., D.R. Tavris, L.K. Hansen, J. Pratt-Shelley, and J.A. Dellinger. 1997. 

Concentrations of blood and hair mercury and serum PCBs in an Ojibwa population that consumes Great

Lakes region fish. Clinical Toxicology. 35(4):377-386.

Gill, G. A., W.M. Landing, J.L. Guentzel, E. Prestbo, and C.D. Pollman. 1996. Total and reactive

gaseous mercury measurements in Florida: The FAMS project. Presented at the fourth international

conference on Mercury as a Global Pollutant, Congress Centre Hamburg, Germany.

Golomb, D., D. Ryan, N. Eby, J. Underhill, and S. Zemba. 1997a. Atmospheric deposition of toxics

onto Massachusetts Bay - I. Metals. Atmos. Environ. 31(9):1349-1359.

Golomb, D. D. Ryan, J. Underhill, T. Wade, and S. Zemba. 1997b. Atmospheric deposition of toxics

onto Massachusetts Bay - II. Polycyclic aromatic hydrocarbons. Atmos. Environ. 31(9):1361-1368.

Goolsby et al. 1998. Gulf of Mexico Hypoxia Assessment, Topic No. 3. Flux and Sources of Nutrients in

the Mississippi - Atchafalaya River Basin. Committee on Environmental and Natural Resources Hypoxia

Working Group for the Mississippi/Gulf of Mexico Watershed Nutrient Task Force (in review). As cited

by: Paerl 1999.

Guentzel, J.L., W.M. Landing, G.A. Gill, and C.D. Pollman. 1995. Atmospheric deposition of mercury

in Florida: The FAMS project (1992-1994). Water Air Soil Poll. 80: 373-382.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-5

Guillette, L.J., Jr., J.W. Brock, A.A. Rooney, and A.R. Woodward. 1999. Serum concentrations of

various environmental contaminants and their relationship to sex steroid concentrations and phallus size

in juvenile American alligators. Arch. Environ. Contam. Toxicol. 36(4): 447.

Gustafson, K.E., and R.M. Dickhut. 1997. Particle/gas concentrations and distributions of PAHs in the

atmosphere of southern Chesapeake Bay. Environ. Sci. Technol. 31(1):140-147.

Guthrie, P.D, D. Axelrad, G.E. Mansell, D. Gao, T Braverman, P. Cocca, and R.D. Atkinson. 1999a.

Integrated Air Quality Modeling for Regulatory Applications: 1. Description of REMSAD. Submitted to

Atmospheric Environment.

Guthrie, P.D, D. Axelrad, G.E. Mansell, D. Gao, T Braverman, P. Cocca, and R.D. Atkinson. 1999b.

Integrated Air Quality Modeling for Regulatory Applications: 2. Evaluation of REMSAD 1990 Base

Case. Submitted to Atmospheric Environment.

Haffner, G.D., C.A. Straughan, D.V. Weseloh, and R. Lazar. 1997. Levels of polychlorinated biphenyls,

including coplanar congeners, and 2,3,7,8-T4CDD toxic equivalents in double-crested cormorant and

herring gull eggs from Lake Erie and Lake Ontario: A comparison between 1981 and 1992. J. Great

Lakes Res. 23(1): 52-60.

Hanson, P.J., S.E. Lindberg, T.A. Tabberer, J.G. Owens, and K.H. Kim. 1995. Foliar exchange of

mercury vapor: evidence for a compensation point. Water Air Soil Pollut. 80: 373-382.

Hartig, J.H., M.A. Zarull, T.B. Reynoldson, G. Mikol, V.A. Harris, R.G. Randall, and V.W. Cairns. 

1997. Quantifying targets for rehabilitating degraded areas of the Great Lakes. Environ. Management

21(5):713-723.

Hartwell, S.I., C.E. Dawson, D.H. Jordhal, E.Q. Durell. 1995. Demonstration of a method to correlate

measures of ambient toxicity to fish community diversity. Maryland Department of Natural Resources,

Annapolis, MD. January 1995.

Henry, K.S., K. Kannan, B.W. Nagy, N.R. Kevern, M.J., Zabik, and J.P. Giesy. 1998. Concentrations

and hazard assessment of organochlorine contaminants and mercury in smallmouth bass from a remote

lake in the upper peninsula of Michigan. Arch. Environ. Contam. Toxicol. 34:81-86.

Hessen, D.O., A. Henriksen, A. Hindar, J. Mulder, K. Tørseth, and N. Vagstad. 1997. Human impacts

on the nitrogen cycle: A global problem judged from a local perspective. 26(5):321-325.

Hewett, M.M. 1998. Memorandum from Michael M. Hewett to Howard L. Rhodes. August 26, 1998.

Hicks, B.B. 1998. Network Investigations of Dry Deposition. NOAA Air Resources Laboratory.

AIRMoN-Dry Web site: http://www.arl.noaa.gov/research/projects/airmon_dry.html. December 9, 1998.

Hillery, B.R., Basu, I., Sweet, C.W., and R.A. Hites. 1997. Temporal and spatial trends in a long-term

study of gas-phase PCB concentrations near the Great Lakes. Environ. Sci. Technol. 31(6):1811-1816.

Hinga, K.R., A.A. Keller, and C.A. Oviatt. 1991. Atmospheric deposition and nitrogen inputs to coastal

waters. Ambio 20:256-260. As cited in: Valiela et. al. (1997).
References

Page R-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Hoff, R.M., Strachan, W.M.J., Sweet, C.W., Chan, C.H., Shackleton, M., Bidleman, T.F., Brice, K.A.,

Burniston, D.A., Cussion, S., Gatz, D.F., Harlin, K., and W.H. Schroeder. 1996. Atmospheric deposition

of toxic chemicals to the Great Lakes: A review of data through 1994. Atmos. Environ. 30(20):3505-

3527.

Hoyer, M., J. Burke, and G. Keeler. 1995. Water Quality Analysis Simulation Program (WASP), 80. 

Huestis, S.Y., M.R. Servos, D.M. Whittle, M. van den Heuvel, and D.G. Dixon. 1997. Evaluation of

temporal and age-related trends of chemically and biologically generated 2,3,7,8-tetrachlorodibenzo-pdioxin equivalents in Lake Ontario lake trout, 1977 to 1993. Environ. Toxicol. Chem. 16(2):154-164.

Hughes, K.D, P.J. Ewins, and K.E. Clark. 1997. A comparison of mercury levels in feathers and eggs of

Osprey (Pandion haliaetus) in the North American Great Lakes. Arch. Environ. Contam. Toxicol.

33:441-452.

Huntley, S.L., H. Carlson-Lynch, G.W. Johnson, D.J. Paustenbach, and B.L. Finley. 1998. Identification

of historical PCDD/F sources in Newark Bay Estuary subsurface sediments using polytopic vector

analysis and radioisotope dating techniques. Chemosphere 36(6):1167-1185.

Hurley, J.P., S.E. Cowell, M.M. Shafer, and P.E. Hughes. 1998a. Partitioning and transport of total and

methyl mercury in the lower Fox River, Wisconsin. Environ. Sci. Technol. 32:1424-1432.

Hurley, J.P., S.E. Cowell, M.M. Shafer, and P.E. Hughes. 1998b. Tributary loading of mercury to Lake

Michigan: Importance of seasonal events and phase partitioning. Sci. Tot. Environ. 213: 129-137. 

Ion, J. Y. de Lafontaine, P. Dumont, and L. Lapierre. 1997. Contaminant levels in St. Lawrence River

yellow perch (Perca flavescens): Spatial variation and implications for monitoring. Can. J. Fish. Aquat.

Sci. 54:2930-2946.

Jantunen, L.M, and T. Bidleman. 1996. Air-water gas exchange of hexachlorocyclohexanes (HCHs) and

the enantiomers of "-HCH in arctic regions. J. Geophys. Res. 101(D22):28,837-28,846.

Jaworski, N.A., R.W. Howarth, and L.J. Hetling. 1997. Atmospheric deposition of nitrogen oxides onto

the landscape contributes to coastal eutrophication in the northeast United States. Environ. Sci. Technol. 

31(7):1995-2004.

Karls, J.F., and E.R. Christensen. 1998. Carbon particles in dated sediments from Lake Michigan, Green

Bay, and tributaries. Environ. Sci. Technol. 32:225-231.

Karuppiah, M., and G. Gupta. 1998. Chronological changes in toxicity of and heavy metals in sediments

of two Chesapeake Bay tributaries. J. Haz. Mat. 59:159-166.

Koopman-Esseboom, C., Weisglas-Kuperus, N., de Ridder, M.A.J., Van Der Paauw, C.G., Tuinstra,

L.G.M.T., Sauer, P.J.J. 1996. Effects of polychlorinated biphenyl/dioxin exposure and feeding type on

infants’ mental and psychomotor development. Pediatrics. 97(5):700-706.

Krabbenhoft, D.P. 1996. Mercury Studies in the Florida Everglades. U.S. Department of the Interior -

U.S. Geological Survey. Fact Sheet FS-166-96.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-7

Krupnick, A., V. McConnel, D. Austin, M. Cannon, T. Stoessel, and B. Morton. 1998. The Chesapeake

Bay and the Control of NOx Emissions: A Policy Analysis. Resources for the Future Discussion Paper

98-46, Resources for the Future, Washington, DC.

Kucklick, J.R., and J.E. Baker. 1998. Organochlorines in Lake Superior’s food web. Environ. Sci.

Technol. 32:1192-1198.

Lake Champlain Basin Program. 1999. www.anr.state.vt.us/champ/ helthsum.htm. March 11, 1999.

Lake Champlain Basin Program. 1998. Long-Term Water Quality and Biological Monitoring Project for

Lake Champlain, Cumulative Report for Project Years 1992-1996. Prepared by the Vermont Department

of Environmental Conservation and the New York State Department of Environmental Conservation for

the Lake Champlain Basin Program. Technical Report No. 26. March 1998.

Lake Champlain Basin Program. 1996a. Opportunities for Action, an Evolving Plan for the Future of the

Lake Champlain Basin. Prepared by the Lake Champlain Management Conference, Lake Champlain

Basin Program, Grand Isle, VT. October 1996.

Lake Champlain Basin Program. 1996b. Background Technical Information for: Opportunities for

Action -- An Evolving Plan for the Future of the Lake Champlain Basin. Prepared by the Lake

Champlain Basin Program for the Lake Champlain Management Conference. June 1996.

Landis, M.S. 1998. Assessing the atmospheric deposition of mercury to Lake Michigan: The importance

of the Chicago/Gary urban area on wet and dry deposition. Ph.D. Thesis, University of Michigan, Ann

Arbor.

Lauenstein, G.G., and K.D. Daskalakis. 1999. U.S. Long-term Coastal Contaminant Temporal Trends

Determined From Mollusk Monitoring Programs, 1965-1993. Marine Pollution Bulletin. 37(1-2): 6-13.

LeBar, G. and D. Parrish. 1996. Bioenergetics Modeling for Lake Trout and other Top Predators in Lake

Champlain. Lake Champlain Basin Program, Technical Report No. 21. December 1996. 

Lemieux, P.M., C.W. Lee, J.D. Kilgroe, and J.V. Ryan. 1999. Emissions of polychlorinated biphenyls

as products of incomplete combustion from incinerators. For presentation at the International

Conference on Incineration and Thermal Treatment Technologies, May 10-14, 1999, Orlando, FL. U.S.

EPA, Air Pollution Prevention and Control Division.

Leonard, D., R. Reash, D. Porcella, A. Paralkar, K. Summers, and S. Gherini. 1995. Use of the Mercury

Cycling Model (MCM) to predict the fate of mercury in the Great Lakes. Water, Air and Soil Pollution. 

80:519-528. 

Li, Y.F., T.F. Bidleman, L.A. Barrie, and L.L. McConnell. 1998. Global hexachlorocyclohexane use

trends and their impact on the arctic atmospheric environment. Geophys. Res. Letters 25(1):39-41.

Lindberg, S.E. and W.J. Stratton. 1998. Atmospheric mercury speciation: Concentrations and behavior

of reactive gaseous mercury in ambient air. Environmental Science and Technology 32(1):49-57.

Lindström, G., Hooper, K., Petreas, M., Stephens, R., and Gilman, A. 1995. Workshop on perinatal

exposure to dioxin-like compounds. I. Summary. Environmental Health Perspectives 103 (Suppl.

2):135-138.
References

Page R-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Linker, Lewis C. 1998. Phase IV Chesapeake Bay Watershed Model Scenario Results.

Linton, T.K., I.J. Morgan, S.D. Reid, and C.M. Wood. 1998. Long-term exposure to small temperature

increase and sublethal ammonia in hardwater acclimated rainbow trout: Does acclimation occur? 

Aquatic Toxicology. 40:171-191.

Liu, K., and R.M. Dickhut. 1998. Effects of wind speed and particulate matter source on surface

microlayer characteristics and enrichment of organic matter in southern Chesapeake Bay. Journal of

Geophysical Research. 103(D9):10,571-10,577.

Liu, K., and R.M. Dickhut. 1997. Surface microlayer enrichment of polycyclic aromatic hydrocarbons

in Southern Chesapeake Bay. Environ. Sci. Technol. 31:2777-2781.

Logan, D. 1998. A Review of EPRI Mercury Cycling Models. PPRP-113. Maryland Power Plant

Research Program, Maryland Department of Natural Resources, Annapolis, MD.

Long, E.R. and H.S. Greening. 1999. Chemical contamination in Tampa Bay: Extent, toxicity, potential

sources and possible sediment quality management plans. Special Report 1999. National Oceanic and

Atmospheric Administration and Tampa Bay National Estuary Program.

Lonky, E., Reihman, J., Darvill, T., Mather, J., and Daly, H. 1996. Neonatal behavioral assessment scale

performance in humans influenced by maternal consumption of environmentally contaminated Lake

Ontario fish. J. Great Lakes Res. 22(2):198-212.

Lu, J.Y., W.H. Schroeder, T. Berg, J. Munthe, D. Schneeberger, and F. Schaedlich. 1998. A device for

sampling and determination of total particulate mercury in ambient air. Analytical Chemistry

70(11):2403-2408.

Mackay, D. and E. Bentzen. 1997. The role of the atmosphere in Great Lakes contamination. 

Atmospheric Environment. 31(23):4045-4047.

Mason, R.P., N.M. Lawson, K.A. Sullivan. 1997. Atmospheric deposition to the Chesapeake Bay

watershed -- Regional and local sources. Atmospheric Environment. 31(21):3531-3540.

Mason, R.P. and K.A. Sullivan. 1997. Mercury in Lake Michigan. Environ. Sci. Technol. 31:942-947.

McClelland, J.W., and I. Valiela. 1998. Changes in food web structure under the influence of increased

anthropogenic nitrogen inputs to estuaries. Mar. Ecol. Prog. Ser. 168:259-271.

McIntosh, A., M. Watzin, and E. Brown (Eds.). 1997. Lake Champlain Sediment Toxics Assessment

Program, An Assessment of Sediment-Associated Contaminants in Lake Champlain -- Phase II. Prepared

for the Lake Champlain Management Conference. Lake Champlain Basin Program, Technical Report

No. 23. October 1997.

Metcalfe, C.D., T.L. Metcalfe, G. Riddle, and G.D. Haffner. 1997a. Aromatic hydrocarbons in biota

from the Detroit River and western Lake Erie. J. Great Lakes Res. 23(2):160-168.

Metcalfe, C.D., T.L. Metcalfe, J.A. Cormier, S.Y. Huestis, and A.J. Nimi. 1997b. Early life-stage

mortalities of Japanese Medaka (Oryzias Latipes) exposed to polychlorinated diphenyl ethers. 

Environmental Toxicology and Chemistry. 16(8):1749-1754.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-9

Michigan Department of Environmental Quality. 1998. Draft Quality Assurance Project Plan: DDT

Concentrations in the Soil and Air of South Haven, Michigan. March 1998. EPA Grant GL985663.

Millette, T. 1997. Development of Land Cover/Land Use Geographic Information System Data Layer for

the Lake Champlain Basin and Vermont Northern Forest Lands Project Areas. Lake Champlain Basin

Program, Technical Report No. 24. October 1997.

Moffat, A.S. 1998. Global nitrogen overload grows critical. Science. 279:988-989.

Morgan, J.N., M.R. Berry, and R.L. Graves. 1997. Effects of commonly used cooking practices on total

mercury concentration in fish and their impact on exposure assessments. Journal of Exposure Analysis

and Environmental Epidemiology. 7(1):119-133.

Murray, George. 1998. Personal communication between George Murray, NC DENR and John

Ackermann, U.S. EPA Region 4. September 9, 1998.

NADP/NTN. 1998a. National Atmospheric Deposition Program (NRSP-3)/National Trends Network. 

NADP Program Office, Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL 61820.

NADP/NTN. 1998b. National Atmospheric Deposition Program/National Trends Network. 

http://nadp.sws.uiuc.edu. October 1998.

National Oceanic and Atmospheric Administration (NOAA). 1999, on-line. Sediment Toxicity by Jawed

Hameedi, Edward Long, and Michelle R. Harmon. NOAA’s State of the Coast Project. Silver Spring,

MD: NOAA. http://state-of-coast.noaa.gov/bulletins/html/sed_15/sed.html.

National Oceanic and Atmospheric Administration (NOAA). 1998, on-line. Chemical Contaminants in

Oysters and Mussels, by Tom O’Connor. NOAA’s State of the Coast Report. Silver Spring, MD. 

http://state_of_coast.noaa.gov/bulletins/html/ccom_05/ccom.html.

National Oceanic and Atmospheric Administration. 1996. Estuarine Eutrophication Survey: Volume 1:

South Atlantic Region. Strategic Environmental Assessment Division, National Ocean Service, Silver

Spring, MD.

National Oceanic and Atmospheric Administration. 1997a. Estuarine Eutrophication Survey: Volume 2:

Mid-Atlantic Region. Strategic Environmental Assessment Division, National Ocean Service, Silver

Spring, MD.

National Oceanic and Atmospheric Administration. 1997b. Estuarine Eutrophication Survey: Volume 3:

North Atlantic Region. Strategic Environmental Assessment Division, National Ocean Service, Silver

Spring, MD.

National Oceanic and Atmospheric Administration. 1997c. Estuarine Eutrophication Survey: Volume 1:

Gulf of Mexico Region. Strategic Environmental Assessment Division, National Ocean Service, Silver

Spring, MD.

National Oceanic and Atmospheric Administration, National Estuarine Research Reserve System

(NOAA NERRS). 1998. inlet.geol.sc.edu/cdmoweb/html/overview.html. September 30, 1998. 
References

Page R-10 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Nelson, E.C., L.L. McConnell, and J.E. Baker. 1998. Diffusive exchange of gaseous polycyclic aromatic

hydrocarbons and polychlorinated biphenyls across the air-water interface of the Chesapeake Bay. 

Environ. Sci. Technol. 32: 912-919.

Nixon, S.W., S. L. Granger, and B. L. Nowicki. 1995. An assessment of the annual mass balance of

carbon, nitrogen, and phosphorous in Narragansett Bay. Biogeochem. 31:15-61.

North American Agreement on Environmental Cooperation (NAAEC). 1999. 

www.naaec.gc.ca/english/index.html. 

Northeast States for Coordinated Air Use Management (NESCAUM). 1998. Northeast States and

Eastern Canadian Provinces Mercury Study: A Framework for Action. 

O’Connor, T.P. 1999. Mussel Watch results from 1986 to 1996. Marine. Pollut. Bull. 37(1-2):14-19.

Offenberg, J.H. and J.E. Baker. 1997. Polychlorinated biphenyls in Chicago precipitation: Enhanced

wet deposition to near-shore Lake Michigan. Environ. Sci. Technol. 31:1534-1538.

Paerl, H.W. 1999. Comments on initial draft of: Deposition of air pollutants to the Great Waters; Third

Report to Congress. Letter to Dale Evarts, EPA/OAQPS, 17 February 1999.

Paerl, H.W. 1997a. Coastal eutrophication and harmful algal blooms: importance of atmospheric

deposition and groundwater as “new” nitrogen and other nutrient sources. Limnol. Oceanogr. 42: 1154-

1165.

Paerl, H.W. 1997b. Comments on draft regulatory impact analysis, June 5, 1997. University of North

Carolina Marine Institute, Morehead City, NC. Personal communication as cited by U.S. EPA 1997g.

Paerl, H.W., and M.L. Fogel. 1994. Isotopic characterization of atmospheric nitrogen inputs as sources of

enhanced primary production in coastal Atlantic ocean waters. Marine Biol. 119: 635-645. As cited in:

Valigura et. al. 1997.

Paerl, H. W., J.L. Pinckney, J. Fear, and P. L. Peierls. 1998. Ecosystem responses to internal and

watershed organic matter loading: Consequences for hypoxia in the eutrophying Neuse River Estuary,

North Carolina, USA. Mar. Ecol. Progr. Ser. 166: 17-25.

Paerl, H.W., J.D. Willey, M. Go, B.L. Peierls, J.L Pinckney, and M.L. Fogel. 1999. Rainfall stimulation

of primary production in western Atlantic Ocean waters: Roles of different nitrogen sources and colimiting nutrients. Mar. Ecol. Progr. Ser. 176: 205-214.

Pai, P., P. Karamchandani, C. Seigneur, and M. Allan. 1999. Sensitivity of simulated atmospheric

mercury concentrations and deposition to model input parameters. Journal of Geophysical Research. 

104(D11): 13855-13868.

Paode, R.D., S.C. Sofuoglu, J. Sivadechathep, K.E. Noll, and T.M. Holsen. 1998. Dry deposition fluxes

and mass size distributions of Pb, Cu, and Zn measured in southern Lake Michigan during AEOLOS. 

Environ. Sci. Technol. 32: 1629-1635.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-11

Pearson, R.F., D.L. Swackhamer, S.J. Eisenreich, and D.T. Long. 1998. Atmospheric inputs of

polychlorinated dibenzo-p-dioxins and dibenzofurans to the Great Lakes: Compositional comparison of

PCDD and PCDF in sediments. J. Great Lakes Res. 24(1):65-82.

Pearson, R.F., D.L. Swackhamer, S.J. Eisenreich, and D.T. Long. 1997a. Concentrations,

accumulations, and inventories of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments of

the Great Lakes. Environ. Sci. Technol. 31:2903-2909.

Pearson, R.F., D.L. Swackhamer, S.J. Eisenreich, and D.T. Long. 1997b. Concentrations,

accumulations, and inventories of toxaphene in sediments of the Great Lakes. Environ. Sci. Technol.

31:3523-3529.

Peierls, B.L., and H. W. Paerl. 1997. Bioavailability of Atmospheric organic nitrogen deposition to

coastal phytoplankton. Limnol. Oceanogr. 42(8):1819-1823

Pellettieri, M.B., W.H. Hallenbeck, G.R. Brenniman, M. Cailas, and M. Clark. 1996. PCB intake from

sport fishing along the northern Illinois shore of Lake Michigan. Bull. Environ. Contam. Toxicol.

57:766-770.

Pelley, J. 1998 What is causing new algal blooms? Environ. Sci. Technol. January 1, 1998.

Pichlmayer, F., W. Schöner, P. Seibert, W. Stichler, and D. Wagenbach. 1998. Stable isotope analysis

for characterization of pollutants at high elevation alpine sites. Atmos. Environ. 32(23): 4075-4085.

Pirrone, N., I. Allegrini, G.J. Keeler, J.O. Nriagu, R. Rossmann, and J.A. Robbins. 1998. Historical

atmospheric mercury emissions and depositions in North America compared to mercury accumulations in

sedimentary records. Atmospheric Environment. 32(5):929-940.

Pirrone, N. and G.J. Keeler. 1997. A Computer-based Framework to Model Acceptable Loadings of

Mercury to the Atmosphere to Protect Water Quality. Report submitted to Grants Management Office,

Office of Policy and Management, U.S. EPA, Atlanta, GA, 30365. Revised December 1997.

Pirrone, N. and G.J. Keeler. 1996. A preliminary assessment of the urban pollution in the Great Lakes

region. Science of the Total Environment. 189/190:91-98.

Pirrone, N., G. Keeler, and J. Nriagu. 1996. Regional differences in worldwide emissions of mercury to

the atmosphere. Atmos. Environ. 30(7): 2981-2987.

Quemerais, B. and K.R. Lum. 1997. Distribution and temporal variation of cadmium in the St.

Lawrence River basin. Aquatic Sciences. 59:243-259.

Rabalais, N.R., R.E. Turner, D. Justice, Q. Dortch, W. Wiseman, and B.K. Sen Gupta. 1996. Nutrient

Changes to the Mississippi River system and responses on the adjacent continental shelf. Estuaries. 19:

386-407

Rea, A.W., J. Graney, G.J. Keeler and T. Scherbatskoy. 1998. Trace Element Concentrations in Foliage

Over Time. Presented at Lake Champlain Research Consortium, 1998 Spring Conference, Burlington,

VT. May 26-28.
References

Page R-12 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Rea, A.W., G.J. Keeler, and T. Scherbatskoy. 1996. The deposition of mercury in throughfall and

litterfall in the Lake Champlain watershed: A short-term study. Atmospheric Environment. 

30(19):3257-3263.

Ridal, J.J., T.F. Bidleman, B.R. Kerman, M.E. Fox, and W.M.J. Strachan. 1997. Enantiomers of "-

hexachlorocyclohexane as tracers of air-water gas exchange in Lake Ontario. Environ. Sci. Technol.

31:1940-1945.

Russell, K.M., J.N. Galloway, S.A. Macko, J.L. Moody, and J.R. Scudlark. 1998. Sources of nitrogen in

wet deposition to the Chesapeake Bay region. Atmos. Environ. 32(14/15): 2453-2465.

Salama, A.A., M.A.M. Mohamed, B. Duval, T.L. Potterk, and R.E. Levin. 1998. Polychlorinated

biphenyl concentration in raw and cooked North Atlantic bluefish (Pomatomus saltatrix) fillets. J. Agric.

Food Chem. 46:1359-1362.

San Francisco Estuary Institute. 1997. 1996 Annual Report: San Francisco Estuary Regional Monitoring

Program for Trace Substances. December. 

Scherbatskoy, T., R. Poirot, B.J.B. Stunder, and R. Artz. 1999. Current knowledge of air pollution and

air resources issues in the Lake Champlain basin. In Lake Champlain in Transition: From Research

Toward Restoration. Edited by Thomas O. Manley and Patricia L. Manley. Water Resources

Monograph Series, Vol. 14. American Geophysical Union.

Scherbatskoy, T., J.B. Shanley, G. Keeler. 1998. Factors controlling mercury transport in an upland

forested catchment. Water, Air, and Soil Pollution. 105:427-438.

Scherbatskoy, T., J.M. Burke, A.W. Rea and G.J. Keeler. 1997. Atmospheric mercury deposition and

cycling in the Lake Champlain Basin of Vermont. In: J.E. Baker (ed.) Atmospheric Deposition of

Contaminants to the Great Lakes and Coastal Waters. SETAC Press. 1997.

Schroeder, W.H., and J. Munthe. 1998. Atmospheric mercury - An overview. Atmos. Environ. 

32(5):809-822.

Scudlark, J.R., K.M. Russell, J.N. Galloway, T.M. Church, and W.C. Keene. 1998. Organic nitrogen in

precipitation at the mid-Atlantic U.S. coast – Methods evaluation and preliminary measurements. 

Atmospheric Environment. 32(10):1719-1728.

Scudlark, J.R., and T. M. Church. 1993. Atmospheric input of organic nitrogen to Delaware Bay.

Estuaries. 16: 747-759. As cited in: Valigura et. al. 1997.

Shanley, J.B., A.F. Donlon, T. Scherbatskoy, and G.J. Keeler. 1999. Mercury cycling and transport in

the Lake Champlain basin. In Lake Champlain in Transition: From Research Toward Restoration. 

Edited by Thomas O. Manley and Patricia L. Manley. Water Resources Monograph Series, Vol. 14. 

American Geophysical Union..

Sharma, M., E.A. McBean, and J. Marsalek. 1997. Source characterization of polycyclic aromatic

hydrocarbons in street and creek sediments. Water Qual. Res. J. Canada. 32(1):23-35.

Short, F.T., and D.M. Burdick. 1996. Quantifying eelgrass habitat loss in relation to housing

development and nitrogen loading in Waquoit Bay, Massachusetts. Estuaries. 19(3):730-739.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-13

Simcik, M. F., S.J. Eisenreich, K.A. Golden, S. Liu, E. Lipiatou, D.L. Swackhamer, and D.T. Long. 

1996. Atmospheric loading of polycyclic aromatic hydrocarbons to Lake Michigan as recorded in the

sediments. Environ. Sci. Technol. 30:3039-3046.

Simcik, M.F., T.P. Franz, H. Zhang, and S.J. Eisenreich. 1998. Gas-particle partitioning of PCBs and

PAHs in the Chicago urban and adjacent coastal atmosphere: States of equilibrium. Environ. Sci.

Technol. 32:251-257.

Simcik, M.F., Zhang, H., Eisenreich, S.J., and T.P. Franz. 1997. Urban contamination of the

Chicago/coastal Lake Michigan atmosphere by PCBs and PAHs during AEOLOS. Environ. Sci.

Technol. 31(7):2141-2147.

Stevens, R. K., Keeler, G. K., Mamane, Y., Prestbo, E. 1998a. Preliminary evaluation of manually

operated thermal annular denuder to collect reactive gas-phase mercury (RGM). For presentation at the

Measurement and Speciation of Mercury in Source Emissions In Support of Regulatory Programs and

Source-Receptor Modeling: An expert panel workshop, U.S. EPA, NERL, Research Triangle Park, NC,

March 1999.

Stevens, R. K., Schaedlich, F. A., Schneeberger, D. R., Prestbo, E., Lindberg, S., Keeler, G. 1998b. 

Automated instrument designed to measure Hg0 and HgCl2 in near real time: Design and operational

characteristics. Presented at the Air & Waste Management Association’s conference on Measurement of

Toxic and Related Air Pollutants, Research Triangle Park, North Carolina.

Stober, J., Scheidt, D., Jones, R., Thornton, K., Ambrose, R., and D. France. 1996. South Florida

Ecosystem Assessment Interim Report. United States Environmental Protection Agency Region IV,

Science and Ecosystem Support Division. Athens, GA. EPA-904-R-96-008.

Stoddard, J.L., C.T. Driscoll, J.S. Kahl, and J.H. Kellogg. 1998. A regional analysis of lake acidification

trends for the Northeast U.S., 1982-1994. Environ. Monit. Assess. 51: 399-413.

Su, M. and E.R. Christensen. 1997. Apportionment of sources of polychlorinated dibenzo-p-dioxins and

dibenzofurans by a chemical mass balance model. Wat. Res. 31(12): 2935-2948.

Sweet, C.W., A. Weiss, and S.J. Vermette. 1998. Atmospheric deposition of trace metals at three sites

near the Great Lakes. Water, Air and Soil Pollution. 103:423-439.

Sweet, C.W., E. Prestbo, B. Brunette. 1999. Atmospheric wet deposition of mercury in North America. 

Proceedings of the 92nd Annual Meeting of the Air and Waste Management Association. June 21-23,

1999, St. Louis, MO.

Talbot, R. and B. Mosher. 1998. Atmospheric Nitrogen Deposition in Great Bay Estuary, New

Hampshire. Presented at the National Estuary Programs Atmospheric Deposition Workshop. Annapolis,

MD. October 20-21, 1998.

Tibbetts, J. 1998. Toxic Tides. Environ. Health Perspectives. 106(7): A326 - A331.

Tilden, J., L.P. Hanrahan, H. Anderson, C. Palit, J. Olson, W. Mac Kenzie, and the Great Lakes Sport

Fish Consortium. 1997. Health advisories for consumers of Great Lakes sport fish: Is the message being

received? Environmental Health Perspectives. 105(12):1360-1365.
References

Page R-14 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

U.S./Canada IADN Scientific Steering Committee. 1998. Technical summary of progress under the

integrated atmospheric depositions program 1990-1996.

U.S. EPA 1999a. 1993 National Toxics Inventory (NTI) Version 9901 (as of November 15, 1999). 

Emission Factor and Inventory Group, Office of Air Quality Planning and Standards.

U.S. EPA. 1999b. Fact Sheet: Voluntary Partnership with the American Hospital Association to Reduce

Hospital Waste. Office of Prevention, Pesticides, and Toxics. EPA 742-F-99-016.

U.S. EPA. 1999c. Regulatory Announcement: EPA’s Program for Cleaner Vehicles and Cleaner

Gasoline. Office of Mobile Sources. EPA420-F-99-051. December 1999. 

U.S. EPA. 1999d. Residual Risk Report to Congress. Office of Air Quality Planning and Standards. 

EPA-453/R-99-001. March 1999.

U.S. EPA. 1999e. Total Risk Integrated Methodology (TRIM) Status Report. Office of Air Quality

Planning and Standards. EPA-453-R-99-010. November 1999.

U.S. EPA. 1999f. www.epa.gov/glnpo/health/atsdr.htm. February 3, 1999.

U.S. EPA. 1998a. Clean Water Action Plan: Restoring and Protecting America’s Waters. U.S.

Environmental Protection Agency and U.S. Department of Agriculture, Natural Resource Conservation

Service, Washington, DC. EPA-840-R-98-001. February 1998.

U.S. EPA. 1998b. Condition of the Mid-Atlantic Estuaries. Office of Research and Development. EPA

600-R-98-147.

U.S. EPA. 1998c. Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) Final

Report: Volume I. August 1998.

U.S. EPA. 1998d. EPA’s Contaminated Sediment Management Strategy. U.S. Environmental Protection

Agency, Office of Water. EPA-823-R-98-001. April 1998.

U.S. EPA. 1998e. EPA Third-Generation Air Quality Modeling System. U.S. Environmental Protection

Agency, Office of Research and Development. EPA-600/R-98/069(b). June 1998.

U.S. EPA. 1998f. Fact Sheet: Draft Implementation Guidance for the Revised Ground-level Ozone and

Particulate Matter National Ambient Air Quality Standards and a Regional Haze Program. November 30,

1998.

U.S. EPA. 1998g. Fact Sheet: Existing Hospital/Medical/Infectious Waste Incinerators – (formerly

known as medical waste incinerators or MWI) – Promulgated Subpart Ce Emission Guidelines.

U.S. EPA. 1998h. Fact Sheet: Federal Plan for Large Municipal Waste Combustors. October 30, 1998.

http://www.epa.gov/oar/oaqps/ttn/uatw/129/mwc/rimwc.html#IMP.

U.S. EPA. 1998i. Fact Sheet: Integrated Atmospheric Deposition Monitoring Network. July 21, 1998. 

U.S. EPA. 1998j. Fact Sheet: New Hospital/Medical/Infectious Waste Incinerators – (formerly known

as medical waste incinerators of MWI) – Promulgated Subpart Ec New Source Performance Standards. 
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-15

U.S. EPA. 1998k. Fact sheet: Update: Listing of Fish & Wildlife Advisories. Office of Water. March

1998. EPA-823-F-98-009.

U.S. EPA. 1998l. National Air Quality and Emissions Trends Report, 1997. Office of Air Quality

Planning and Standards. December 1998. EPA 454/R-98-016.

U.S. EPA. 1998m. National Listing of Fish and Wildlife Advisories (NLFWA) Database - 1997. Office

of Water. EPA-823-C-98-001.

U.S. EPA. 1998n. Report Brochure: National Water Quality Inventory – 1996 Report to Congress. 

Office of Water. April. EPA841-F-97-003.

U.S. EPA. 1998o. Report of the Federal Advisory Committee on the Total Maximum Daily Load

(TMDL) Program: The National Advisory Council for Environmental Policy and Technology

(NACEPT). Office of the Administrator. July 1998. EPA 100-R-98-006.

U.S. EPA. 1998p. Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating

Units -- Final Report to Congress. February 1998. EPA 453/R-98-004a.

U.S. EPA. 1998q. The EPA children’s environmental health yearbook: Executive Summary. Office of

Children’s Health Protection. EPA 100-S-98-002.

U.S. EPA. 1998r. The Regional NOx SIP Call and Reduced Atmospheric Deposition of Nitrogen:

Benefits to Selected Estuaries. U.S. EPA. Washington, DC.

U.S. EPA 1998s. United States - Canada Air Quality Agreement: 1998 Progress Report. EPA430-R-98-

016.

U.S. EPA. 1998t. www.epa.gov/children. October 21, 1998.

U.S. EPA. 1998u. www.epa.gov/indian. October 22, 1998.

U.S. EPA. 1998v. www.epa.gov/OWOW/tmdl/tmdlcstt. September 10, 1998.

U.S. EPA 1997a. Benefits of Reducing Deposition of Atmospheric Nitrogen in Estuarine and Coastal

Waters. 

U.S. EPA. 1997b. Deposition of Air Pollutants to the Great Waters: Second Report to Congress. Office

of Air Quality Planning and Standards. EPA-453/R-97-011. June 1997.

U.S. EPA. 1997c. EPA Strategic Plan. U.S. Environmental Protection Agency, Office of the Chief

Financial Officer, Washington, DC. EPA/190-R-97-002. September 1997.

U.S. EPA. 1997d. Fact Sheet: The Voluntary Advanced Technology Incentives Program. EPA-821-F97-012. November 1997.

U.S. EPA. 1997e. Mercury Study Report to Congress (Volumes I - VIII). Office of Air Quality

Planning and Standards and Office of Research and Development. EPA-452/R-97-005. December.
References

Page R-16 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

U.S. EPA. 1997f. National Air Pollutant Emission Trends, 1900 - 1996. Office of Air Quality Planning

and Standards. EPA-454/R-97-011.

U.S. EPA. 1997g. National Air Quality and Emissions Trends Report, 1996. Office of Air Quality

Planning and Standards.

U.S. EPA. 1997h. Nitrogen Oxides: Impacts on Public Health and the Environment. Office of Air and

Radiation. EPA 452/R-97-002

U.S. EPA. 1997i. The Incidence and Severity of Sediment Contamination in Surface Waters of the

United States, Volume 1: National Sediment Quality Survey. U.S. Environmental Protection Agency,

Office of Science and Technology. EPA 823-R-97-006. September 1997.

U.S. EPA. 1997j. The Incidence and Severity of Sediment Contamination in Surface Waters of the

United States, Volume 2: Data Summaries for Areas of Probable Concern. U.S. Environmental

Protection Agency, Office of Science and Technology. EPA 823-R-97-007. September 1997.

U.S. EPA. 1997k. The Incidence and Severity of Sediment Contamination in Surface Waters of the

United States, Volume 3: National Sediment Contaminant Point Source Inventory. U.S. Environmental

Protection Agency, Office of Science and Technology. EPA 823-R-97-008. September 1997.

U.S. EPA. 1996a. Environmental health threats to children. EPA 175-F-96-001. Obtained from

http://www.epa.gov/epadocs/child.htm

U.S. EPA. 1996b. TMDL Development Cost Estimates: Case Studies of 14 TMDLs. Office of Water. 

EPA-R-96-001.

U.S. EPA. 1995. Environmental Justice 1994 Annual Report: Focusing on Environmental Protection for

All People. Office of Environmental Justice. April 1995. EPA/200-R-9J-003.

U.S. EPA. 1994. Deposition of Air Pollutants to the Great Waters: First Report to Congress. Office of

Air Quality Planning and Standards. May 1994. EPA-453/R-93-055.

U.S. EPA and Environment Canada. 1998. Draft Great Lakes Binational Toxics Strategy: Activities by

Partners. November 16, 1998 draft.

 

Valiela, I., G. Collins, J. Kremer, K. Lajtha, M. Geist, B. Seely, J. Brawley, and C.H. Sham. 1997. 

Nitrogen loading from coastal watersheds to receiving estuaries: New method and application. 

Ecological Applications. 7(2):358-380.

Valiela, I., G. Collins, J. Kremer, K. Lajtha, M. Geist, B. Seely, J. Brawley, and C.H. Cham. 1996. 

Nitrogen loading from coastal watershed to receiving waters: Review of methods and calculations of

loading to Waquoit Bay. Ecol. Appl. 7: 358-380.

Valigura, R., M. Kerchner, M. Conley, J. Thomas, Michele Monti, and Bruce Hicks. 1997. Airsheds and

Watersheds II: A Shared Resources Workshop. Chesapeake Bay Program Air Subcommittee. 

Annapolis, MD.
References

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page R-17

VCGI. 1996. Catalog of Digital Spatial Data for the Lake Champlain Basin. Vermont Center for

Geographic Information, Inc. Lake Champlain Basin Program, Technical Report No. 18. September

1996.

Vitousek, P.M., J.D. Aber, R.W. Howarth, G.E. Likens, P.A. Matson, D.W. Schindler, W.H. Schlesinger,

and D.G. Tilman. 1997. Human alteration of the global nitrogen cycle: Sources and consequences. 

Ecological Applications. 7(3):737-750.

Wade, T.L., L. Chambers, P.R. Gardinali, J.L. Sericano, T.J. Jackson, R.J. Tarpley, and R. Suydam. 

1997a. Toxaphene, PCB, DDT and chlordane analyses of Beluga whale blubber. Chemosphere. 34(5-

7):1351-1357.

Wade, T.L., T.J. Jackson, P.R. Gardinali, and L. Chambers. 1997b. PCDD/PCDF sediment

concentration distribution: Casco Bay, Maine, USA. Chemosphere. 34(5-7):1359-1367.

Ward, M. H., S.D. Mark, K. P. Cantor, D.D. Weisenburger, A. Correa-Villasenor, and S. H. Zahm. 1996. 

Drinking water nitrate and the risk of Non-Hodgkin’s Lymphoma. Epidemiology. 7:465-471. As cited

in U.S. EPA 1997f.

Watras, C. and J. Huckabee (eds). 1994. Mercury Pollution: Integration and Synthesis. Lewis

Publishers: Boca Raton.

Zarbock, P.E., A. Janicki, D. Wade, D. Higmuch, and H. Wilson. 1994. Estimates of total nitrogen, total

phosphorous, and total suspended solids loadings to Tampa Bay, Florida. Coastal Environment, Inc., for

the Tampa Bay Estuary Program.
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page Index-1

INDEX OF WATERBODIES

WATERBODIES

Chesapeake Bay

i, iii, I-3, I-5, I-12, I-13, II-1, II-13, II-14, II-16, II-19, II-21, II-26, II-27, II-28, II-29, II-30, II-34,

II-38, II-39, II-40, II-44, II-49, II-50, II-52, II-53, II-54, II-56, II-58, II-60, II-62, II-65, II-66, II-72,

II-73, II-75, III-1, III-34, III-38, III-39, III-40, III-41, III-52, III-65, IV-7, IV-11, IV-13, IV-14, IV15, IV-16, IV-17, IV-18, IV-19, IV-24, V-15

Everglades

III-5, III-53, III-54, III-55, IV-12, IV-13

Great Lakes

i, ii, iii, iv, I-1, I-2, I-3, I-5, I-12, I-13, II-8, II-9, II-11, II-12, II-17, II-18, II-19, II-20, II-21, II-22,

II-23, II-28, II-30, II-31, II-32, II-33, II-34, II-35, II-36, II-37, II-49, II-50, II-57, II-58, II-59, II-60,

II-61, II-63, II-64, II-65, II-66, II-67, II-68, II-69, II-70, II-71, II-73, II-75, III-1, III-31, III-34, III35, III-36, III-37, III-49, III-60, III-66, III-67, III-68, III-69, IV-4, IV-6, IV-7, IV-9, IV-10, IV-13,

IV-15, IV-18, IV-24, V-4, V-7, V-8, V-9, V-10, V-11, V-12, V-14, V-15

Lake Michigan

I-12, II-12, II-13, II-14, II-17, II-21, II-32, II-33,II-36, II-37, II-59, II-60, II-61, II-63, II-64,

II-65, II-66, II-67, II-69, III-34, III-35, III-36, III-37, III-64, IV-13, IV-14, IV-15, IV-16, 

IV-19, IV-22, V-4, V-9

Lake Erie

II-12, II-21, II-33, II-58, II-60, II-61, II-63, II-64, II-65, II-67, III-36, III-37

Lake Superior

II-21, II-32, II-33, II-36, II-56, II-58, II-59, II-60, II-63, II-64, II-65, II-66, II-67, II-69, III30, III-36, III-37, III-59, IV-16, IV-17

Lake Huron

II-31, II-33, II-36, II-59, II-60, II-63, II-64, II-66, II-67, II-69, III-36, III-37, IV-21

Lake Ontario

II-12, II-19, II-33, II-32, II-56, II-60, II-61, II-63, II-64, II-65, II-66, II-67, III-36, II-37,

IV-19, IV-21, IV-22

Gulf of Mexico

I-5, I-13, II-34, II-55, II-56, II-57, II-71, III-1, III-41, III-42, III-48, IV-9, IV-16, IV-17, IV-18

Lake Champlain

i, I-3, I-5, I-12, II-1, II-11, II-14, II-15, II-49, II-50, II-57, II-69, II-73, II-75, III-1, III-37, III-38, V14

Mississippi River/Delta

II-8, II-51, II-54, II-56, III-41, III-42, IV-17
Index of Water Bodies

Page Index-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Neuse River

II-54, III-43

Peconic Bay

II-53, III-42

St. Lawrence River

II-17, II-28, II-60, III-36, V-11

NATIONAL ESTUARY PROGRAM WATERBODIES

Albemarle-Pamlico Estuary

I-3, II-52, II-53, II-56, III-6, III-30, III-42, III-51

Casco Bay

I-3, III-42, III-43

Charlotte Harbor

III-42, III-43

Coastal Bend Bay (and Estuary)

III-42, III-43

Delaware Inland Bays

II-53, III-42, III-43, III-44 

Delaware Estuary (or Bay)

II-16, II-17, II-19, II-30, II-34, II-52, II-53, II-72

Galveston Bay

I-3, II-34, II-72

Long Island Sound

ii, II-13, II-14, II-19, II-27, II-52, II-53, II-54, II-56, II-72, III-42, III-44, V-8

Massachusetts Bay

II-27, II-37, II-38, II-53, III-42, III-44, IV-9

Narragansett Bay

II-52, II-53, II-72, III-44

New York Bight

I-3, II-52, II-53

New York/New Jersey Harbor

II-56, III-42, III-44, III-45

San Francisco Bay (or Estuary)

I-3, II-1, II-76, III-42, III-45
Index of Water Bodies

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page Index-3

Santa Monica Bay

I-3, III-42, III-45

Sarasota Estuary (or Bay) 

II-49, II-53, III-42, III-46

Tampa Bay

I-3, II-49, II-53, II-56, II-70, II-72, III-42, III-46, III-47, III-48

NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM

WATERBODIES

Chesapeake Bay (MD and VA) 

(See above under “Waterbodies”)

Delaware Inland Bays

(See above under “Waterbodies”) 

Delaware Estuary (or Bay)

(See above under “Waterbodies”)

Hudson River

III-45

Narragansett Bay

(See above under “Waterbodies”)

Waquoit Bay

II-51, II-52, II-53, II-55, II-56
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page A-1

APPENDIX A

Major Sources of Information:

Publications and Internet Sites

PUBLICATIONS

Baker, J.E. (ed.). 1997. Atmospheric Deposition of Contaminants to the Great Lakes and Coastal

Waters. SETAC Press. 

Chesapeake Bay Program. 1999, in press. Chesapeake Bay Basin Toxics Loading and Release

Inventory. 

Eisenreich, S.J., and W.M.J. Strachan. 1992. Estimating atmospheric deposition of toxic substances to

the Great Lakes - An update. Report on a workshop held at the Canada Centre for Inland Waters;

January 31-February 2, 1992; Burlington, Ontario. Sponsored by the Great Lakes Protection Fund and

Environment Canada.

Eskin, R.A., K.H. Rowland, and D.Y. Alegre. 1996. Contaminants in Chesapeake Bay Sediments 1984-

1991. Printed by U.S. EPA for the Chesapeake Bay Program. May 1996.

Hartig, J.H., M.A. Zarull, T.B. Reynoldson, G. Mikol, V.A. Harris, R.G. Randall, and V.W. Cairns. 

1997. Quantifying targets for rehabilitating degraded areas of the Great Lakes. Environ. Management

21(5):713-723.

Hoff, R.M., Strachan, W.M.J., Sweet, C.W., Chan, C.H., Shackleton, M., Bidleman, T.F., Brice, K.A.,

Burniston, D.A., Cussion, S., Gatz, D.F., Harlin, K., and W.H. Schroeder. 1996. Atmospheric deposition

of toxic chemicals to the Great Lakes: A review of data through 1994. Atmos. Environ. 30(20):3505-

3527.

Lake Champlain Basin Program. 1998. Long-Term Water Quality and Biological Monitoring Project for

Lake Champlain, Cumulative Report for Project Years 1992-1996. Prepared by the Vermont Department

of Environmental Conservation and the New York State Department of Environmental Conservation for

the Lake Champlain Basin Program. Technical Report No. 26. March 1998.

Mackay, D. and E. Bentzen. 1997. The role of the atmosphere in Great Lakes contamination. Atmos.

Environ. 31(23):4045-4047.

San Francisco Estuary Institute. 1997. 1996 Annual Report: San Francisco Estuary Regional Monitoring

Program for Trace Substances. December.

Schroeder, W.H., and J. Munthe. 1998. Atmospheric mercury - An overview. Atmos. Environ. 

32(5):809-822.

Sweet, C.W., E. Prestbo, B. Brunette. 1999. Atmospheric wet deposition of mercury in North America. 

Proceedings of the 92nd Annual Meeting of the Air and Waste Management Association. June 21-23,

1999, St. Louis, MO.
Appendix A

Major Sources of Information: Publications and Internet Sites

Page A-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

U.S./Canada IADN Scientific Steering Committee. 1998. Technical Summary of Progress Under the

Integrated Atmospheric Depositions Program 1990-1996.

U.S. EPA. 1999. Residual Risk Report to Congress. Office of Air Quality Planning and Standards. 

EPA-453/R-99-001. March 1999.

U.S. EPA. 1998. Condition of the Mid-Atlantic Estuaries. Office of Research and Development. EPA

600-R-98-147.

U.S. EPA. 1998. National Air Quality and Emissions Trends Report, 1997. Office of Air Quality

Planning and Standards. EPA 454/R-98-016. December 1998. 

U.S. EPA. 1998. National Listing of Fish and Wildlife Advisories (NLFWA) Database - 1997. Office

of Water. EPA-823-C-98-001.

U.S. EPA. 1998. Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating

Units -- Final Report to Congress. February 1998. EPA 453/R-98-004a.

U.S. EPA. 1998. The Regional NOx SIP Call and Reduced Atmospheric Deposition of Nitrogen:

Benefits to Selected Estuaries. U.S. EPA. Washington, DC.

U.S. EPA. 1998. United States - Canada Air Quality Agreement: 1998 Progress Report. EPA430-R-98-

016.

U.S. EPA. 1997. Benefits of Reducing Deposition of Atmospheric Nitrogen in Estuarine and Coastal

Waters. 

U.S. EPA. 1997. Deposition of Air Pollutants to the Great Waters: Second Report to Congress. Office

of Air Quality Planning and Standards. EPA-453/R-97-011. June 1997.

U.S. EPA. 1997. Mercury Study Report to Congress (Volumes I - VIII). Office of Air Quality Planning

and Standards and Office of Research and Development. EPA-452/R-97-005. December 1997.

U.S. EPA. 1997. National Air Pollutant Emission Trends, 1900 - 1996. Office of Air Quality Planning

and Standards. EPA-454/R-97-011.

U.S. EPA. 1997. National Air Quality and Emissions Trends Report, 1996. Office of Air Quality

Planning and Standards.

U.S. EPA. 1997. Nitrogen Oxides: Impacts on Public Health and the Environment. Office of Air and

Radiation. EPA 452/R-97-002.

U.S. EPA. 1994. Deposition of Air Pollutants to the Great Waters: First Report to Congress. Office of

Air Quality Planning and Standards. EPA-453/R-93-055. May 1994.

Valigura, R., M. Kerchner, M. Conley, J. Thomas, Michele Monti, and Bruce Hicks. 1997. Airsheds and

Watersheds II: A Shared Resources Workshop. Chesapeake Bay Program Air Subcommittee. 

Annapolis, MD.
Appendix A

Major Sources of Information: Publications and Internet Sites

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page A-3

INTERNET SITES

Chesapeake Bay Program

http://www.chesapeakebay.net

Commission for Environmental Cooperation

http://www.cec.org

Environment Canada Great Lakes Regional Programs

http://www.cciw.ca/glimr/program.html

Great Lakes Information Network

http://www.great-lakes.net

Great Lakes National Program Office 

http://www.epa.gov/glnpo 

Gulf of Mexico Program Office

http://pelican.gmpo.gov

Integrated Atmospheric Deposition Network - Environment Canada

http://airquality.tor.ec.gc.ca/IADN

Integrated Atmospheric Deposition Network - U.S. EPA

http://www.epa.gov/grtlakes/air

International Joint Commission

http://www.ijc.org

Lake Champlain Basin Program

http://www.anr.state.vt.us/champ

Lake Michigan Mass Balance Study (LMMBS)

http://www.epa.gov/glnpo/lmmb

Michigan State Mercury Pollution Prevention

http://www.deq.state.mi.us/ead/p2sect/mercury

National Atmospheric Deposition Program/AIRMoN

http://nadp.sws.uiuc.edu/airmon

National Atmospheric Deposition Program/National Trends Network (NADP/NTN)

http://nadp.sws.uiuc.edu

National Atmospheric Deposition Program/Mercury Deposition Network (NADP/MDN)

http://nadp.sws.uiuc.edu/mdn

National Estuarine Research Reserve System (NERRS)

http://inlet.geol.sc.edu/nerrsintro.html
Appendix A

Major Sources of Information: Publications and Internet Sites

Page A-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

National Estuary Program (NEP)

http://www.epa.gov/nep

NOAA Air Resources Laboratory, AIRMoN-Dry

http://www.arl.noaa.gov/research/projects/airmon_dry.html

North American Agreement on Environmental Cooperation (NAAEC) 

http://www.naaec.gc.ca/english/index.html

Persistent Bioaccumulative Toxics (PBT) Initiative 

http://www.epa.gov/pbt

U.S. Environmental Protection Agency (EPA)

http://www.epa.gov 
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page B-1

APPENDIX B

Detailed Breakdown of Air Emissions Inventory 

by Pollutant for Source Categories Emitting Less than

1 Percent of Total U.S. Emissions

This appendix lists the source categories that contribute less than 1 percent to total U.S.

emissions for mercury and compounds, lead and compounds, cadmium and compounds, dioxins and

furans, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). This

information is from EPA’s Mercury Study Report to Congress (U.S. EPA 1997e) for mercury and

compounds and from EPA’s 1993 National Toxics Inventory (NTI) for the remaining compounds (U.S.

EPA 1999a). This list is referenced in Tables II-1, II-4, II-5, II-11, II-14, and II-22, in which the source

categories contributing greater than 1 percent to total U.S. emissions are listed along with the percent

contribution to total U.S. emissions.

MERCURY AND COMPOUNDS

Batteries

Byproduct Coke

Carbon Black

Crematories

Electrical Apparatus

Flourescent Lamp Recycling

Geothermal Power

Instruments Manufacturing

Lime Manufacturing

Mercury Compounds

Pigments, Oil, etc.

Primary Copper

Primary Lead

Primary Mercury Production

Refineries

Secondary Mercury Production

Sewage Sludge Incinerators

Turf Products

Wood-fired Boilers

LEAD AND COMPOUNDS

 

Abrasive Products

Adhesives and Sealants

Aerospace Industry (Surface Coating)

Agricultural Production

Agricultural Chemicals and Pesticides

Air and Gas Compressors

Air, Water, & Solid Waste Management

Aircraft Engines and Engine Parts Manufacturing

Aircraft Manufacturing

Aircraft Parts and Equipment Manufacturing

Aircraft And Parts

Airports, Flying Fields, & Services

Aluminum Extruded Products

Aluminum Foundries

Aluminum Foundries (Castings)

Aluminum Sheet, Plate, and Foil manufacturing

Aluminum Die-Castings

Ammunition, Except for Small Arms

Amusement Parks

Amusement And Recreation, Nec

Animal Cremation

Asphalt Paving Production

Asphalt Paving Mixtures And Blocks

Asphalt Production

Asphalt Roofing Production

Automotive stampings

Automotive Dealers, Nec

Aviation Gasoline Distribution: Stage I & II

Beet Sugar

Black Liquor Combustion

Blast Furnaces and Steel Mills

Boat Building and Repairing

Bolts, Nuts, Rivets and Washers Manufacturing

Bookbinding And Related Work

Botanical And Zoological Gardens

Brass, Bronze, Copper, Copper Base Alloy Foundries

Bread, Cake, And Related Products

Brick and Structural Clay Tile

Business services, nec (1987)

Canned specialties

Canned Fruits and Vegetables

Carbon and Graphite Products

Carbon Black Manufacture

Carburetors, Pistons, Rings and Valves Manufacturing

Cathode Ray Television Picture Tubes Manufacturing

Cement, Hydraulic (not subject to Portland Cement Regulation)

Ceramic Wall and Floor Tile Manufacturing

Chemical Manufacturing: Explosives & Blasting Agents
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Page B-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

LEAD AND COMPOUNDS (CONTINUED)

Chemical Preparations

Chemical Manufacturing: Cyclic Crude and Intermediate 

Production

Chemicals and Allied Products Manufacturing

Chromium Plating: Chromic Anodizing Plating

Coated Fabrics, not Rubberized, Manufacturing

Coke Ovens: By-product Recovery Plants

Cold Finishing of Steel Shapes

Commercial Printing, Lithographic

Commercial Printing, nec

Commercial Physical Research

Commercial/Institutional Boilers: Coal Combustion, all types

Commercial/Institutional Heating: Anthracite Coal Combustion

Commercial/Institutional Heating: Bituminous and Lignite Coal 

Combustion

Commercial/Institutional Heating: Distillate Oil Combustion

Commercial/Institutional Heating: Natural Gas Combustion

Commercial/Institutional Heating: Residual Oil Combustion

Commercial/Institutional Heating: Wood/Wood Residue 

Combustion

Communications Equipment, nec

Computer Peripheral Equipment, nec

Construction Machinery Manufacturing

Construction (SICs 15-17)

Construction Sand And Gravel

Conveyors and Conveying Equipment Manufacturing

Copper Rolling and Drawing

Copper Foundries

Cordage and Twine

Correctional Institutions

Costume Jewelry

Cotton

Cottonseed Oil Mills

Courts

Crop Preparation Services For Market

Crude petroleum and natural gas

Crude Petroleum Pipelines

Crushed And Broken Limestone

Crushed And Broken Stone, Nec

Crushed And Broken Granite

Current-carrying Wiring Devices

Custom Compound Purchased Resins Manufacturing

Dehydrated fruits, vegetables, and soups

Depository Institutions

Dog and Cat Food

Drum and Barrel Reclamation

Durable Goods, Nec

Electric and other services combined

Electric Lamps

Electric services

Electrical Equipment and Supplies, nec

Electrical Industrial Apparatus, nec

Electrical Apparatus and Equipment

Electromedical Equipment Manufacturing

Electrometallurgical Products

Electron Tubes Manufacturing

Electronic Components, nec

Electronic Computers

Electronic Computing Equipment

Electronic Connectors

Electronic Capacitors Manufacturing

Electronic Resistors

Elevators and Moving Stairways Manufacturing

Engine Electric Equipment

Engineering Services

Environmental Controls Manufacturing

Fabricated Metal Products, nec

Fabricated Plate Work (Boiler Shops)

Fabricated Rubber Products, nec

Fabricated Structural Metal Manufacturing

Fabricated Structural Metal Products

Farm Machinery and Equipment Manufacturing

Ferroalloy Ores, Except Vanadium

Fertilizers, Mixing only

Flat Glass

Fluid power Valves and Hose Fittings Manufacturing

Fluid Meters and Counting Devices

Food and Agricultural Products: Cotton Ginning

Food Preparations Production

Food Products Machinery Manufacturing

Frozen fruits, fruit juices and vegetables

Funeral Service And Crematories

Furniture and Fixtures Manufacturing

Gas And Other Services Combined

Gaskets, Packing and Sealing Devices Manufacturing

Gasoline Distribution Stage II

Gasoline Distribution Stage I

General Industrial Machinery Manufacturing

General Automotive Repair Shops

General Medical & Surgical Hospitals

Glass Containers

Gold Ores

Grain And Field Beans

Gray and Ductile Iron Foundries

Greeting Cards

Grocery Stores

Guided Missiles and Space Vehicles Manufacturing

Halogenated Solvent Cleaners

Hand and Edge Tools Manufacturing

Hardware Manufacturing

Heating Equipment, Except Electric

Heavy Construction, Nec

Hospitals

Hotels And Motels

Household Cooking Equipment

Household Audio and Video Equipment

Hunting, Trapping, Game Propagation

Industrial Boilers: Residual Oil Combustion

Industrial Boilers: Bituminous and Lignite Coal Combustion

Industrial Boilers: Coal, all types

Industrial Boilers: Distillate Oil Combustion

Industrial Boilers: Natural Gas Combustion

Industrial Boilers: Anthracite Coal Combustion

Industrial Boilers: Waste Oil Combustion

Industrial Boilers: Wood/Wood Residue Combustion

Industrial Gases Manufacturing

Industrial Inorganic Chemical Manufacturing

Industrial machinery and equipment

Industrial Organic Chemicals Manufacturing

Industrial Sand

Industrial Supplies

Industrial Trucks and Tractors Manufacturing

Industrial/Utility Dist. Oil/Diesel Turbines

Inorganic Pigments Manufacturing

Instruments to Measure Electricity

Integrated Iron and Steel Mills
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page B-3

LEAD AND COMPOUNDS (CONTINUED)

Intercity & Rural Bus Transportation

Internal Combustion Engine Manufacturing

Iron and Steel Foundries: Steel Foundries

Iron and Steel Foundries: Steel Investment Foundries

Iron and Steel Forging

Laminated Plastics Plate and Sheet

Lead Pencils, Art Goods Manufacturing

Life Insurance

Lighting Equipment

Lightweight Aggregate Kilns

Lime

Lubricating Oils and Greases

Malleable Iron Foundries

Malt Beverages

Manufacturing Industries Manufacturing

Marine Cargo Handling

Measuring and Controlling Devices, nec

Meat Packing Plants

Membership Sports & Recreation Clubs

Metal cans (3411)

Metal coating and allied services (3479)

Metal Coil (Surface Coating)

Metal Barrels, Drums, and Pails Manufacturing

Metal Foil and Leaf

Metal Forgings and Stampings

Metal Heat Treating Manufacturing

Metal Sanitary Ware Manufacturing

Metal Stampings Manufacturing

Metal Valves

Mineral Wool Manufacturing (includes Wool Fiberglass)

Mineral Wool

Minerals, Ground or Treated Production

Mining Machinery Manufacturing

Miscellaneous Plastics Products

Miscellaneous Fabricated Wire Products

Miscellaneous Metal Work

Miscellaneous Nonmetallic Minerals

Miscellaneous Fabricated Metal Products

Miscellaneous Plastics Products, nec

Mobile Sources: Railroads

Mobile Sources: Non-Road Vehicles and Equipment - 

Commercial Marine Vessels

MON - Continuous Processes

Motion Picture & Video Production

Motor Vehicle Equipment

Motor Vehicle Parts and Accessories Manufacturing

Motor Vehicles and Car Bodies Manufacturing

Motor and Generators Manufacturing

Musical Instruments

National Security

Natural Gas Liquids

Newspapers

Non-road Mobile Vehicles

Noncommercial research organizations (1987)

Noncurrent-Carrying Wiring Devices

Nonferrous Foundries, nec

Nonferrous Rolling and Drawing

Nonferrous Wire Drawing and Insulating

Nonferrous Forgings

Nonferrous Die-castings, Except Aluminum

Nonmetallic Mineral Products Manufacturing

Nursing And Personal Care, Nec

Office Machines

Office Furniture, Except Wood Manufacturing

Oil And Gas Field Services, Nec

Oil and Gas Field Machinery Manufacturing

On-Site Waste Incineration

Open Burning: Forest and Wildfires

Open Burning: Scrap Tires

Ophthalmic Goods

Optical Instruments and Lenses

Ordnance and Accessories Manufacturing

Organic Fibers, Non-cellulosic Manufacturing

Ornamental Nursery Products

Other Structural Clay Products

Paint Application: Medium Shops

Paint Application: Large Shops

Paints and Allied Products Manufacturing

Paper Coated and Laminated, Packaging, nec

Paperboard Mills

Paved Road Dust

Petroleum Refining

Petroleum Refining

Petroleum Refining: Catalytic Cracking Units

Petroleum Refining: Other Petroleum Products

Petroleum Bulk Stations and Terminals

Pharmaceutical Preparations Manufacturing

Phosphatic Fertilizers

Plastics Materials and Resins Manufacturing

Plastics Products Manufacturing

Plastics Foam Products Manufacturing

Plumbing Fixture Fittings and Trim

Porcelain Electrical Supplies

Portland Cement Manufacture: All Fuels

Potash, Soda, And Borate Minerals

Potato Chips and Similar Snacks

Pottery Products, nec

Power Transmission Equipment

Prefabricated Metal Buildings

Prepared Feeds Manufacturing

Primary Aluminum Production

Primary Batteries, Dry and Wet, Manufacturing

Primary Copper

Primary Metal Products Manufacturing

Primary Smelting and Refining of Zinc

Printing Ink

Printing Trades Machinery Manufacturing

Products of Purchased Glass

Pulp mills (2611)

Pulp and Paper: Kraft Recovery Furnaces

Pumps and Pumping Equipment Manufacturing

Radio and Television Communications Equipment (3662)

Radio and Television Communications Equipment (3663)

Railroad Equipment Manufacturing

Railroads, Line-haul Operating

Ready-mixed Concrete

Refrigeration and Heating Equipment Manufacturing

Refuse Systems

Relays and Industrial Controls

Repair services, nec

Residential Bituminous and Lignite Coal Combustion

Residential Care

Residential Distillate Oil Combustion

Residential Anthracite Coal Combustion

Residential Wood/Wood Residue Combustion

Rice Milling

Rubber and Plastic Hose and Belting Manufacturing

Sawmills and Planing Mills, general
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Page B-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

LEAD AND COMPOUNDS (CONTINUED)

Schools & Educational Services, Nec

Scrap And Waste Materials

Screw Machine Products, Bolts, etc.

Screw Machine Products Manufacturing

Search and Navigation Equipment

Secondary Aluminum Smelting

Semiconductors and Related Devices

Semivitreous Table & Kitchenware

Service Industry Machinery

Sewage Sludge Incineration

Sewerage Systems

Sheet Metal Work

Ship Building & Repair

Ship Building And Repairing

Signs and Advertising Displays

Silverware and Plated Ware

Skilled Nursing Care Facilities

Small Arms Ammunition

Small Arms

Soap and Other Detergents Manufacturing

Soil Dust

Space Research and Technology

Space Vehicle Parts and Equipment, nec

Space Propulsion Units and Parts Manufacturing

Special Dies, Tools, Jigs and Fixtures

Special Industry Machinery, nec

Special Trade Contractors, nec

Specialty Hospitals Exc. Psychiatric

Speed Changers, Drives, and Gears

Sporting and Athletic Goods Manufacturing

Stainless Steel Manufacture - EAF

Stationary IC Engines - Diesel

Stationary IC Engines - Natural Gas

Steam And Air-conditioning Supply

Steel Pipe and Tubes Manufacturing

Structural Clay Products, nec

Structure Fires

Surface Active Agents Manufacturing

Surface Coating Operations

Surgical and Medical Instruments Manufacturing

Taconite Iron Ore Processing

Telephone and Telegraph Apparatus

Textile Machinery

Tire Cord and Fabric

Tire Manufacturing

Tires and Inner Tubes

Top & body repair and paint shops (1987)

Transformers, Except Electronic

Travel Trailers and Campers Manufacturing

Truck Trailers

Truck and Bus Bodies

Trucking, Except Local

Turbines and Turbine Generator Sets

Turbines - Natural Gas

U.S. Postal Service

Unpaved Road Dust

Unsupported Plastics Profile Shapes

Unsupported Plastics Film & Sheet

Utility Boilers: Coke

Utility Boilers: Natural Gas Combustion

Utility Boilers: Oil Combustion, all types

Valves and Pipe Fittings Manufacturing

Vehicular Lighting Equipment

Vitreous Plumbing Fixtures

Vitreous China Table and Kitchenware

Waste Disposal: Open Burning (all categories)

Water supply

Wood Products

Wool Fiberglass Manufacturing

X-ray Apparatus and Tubes

CADMIUM AND COMPOUNDS

 

Adhesives and Sealants

Aerospace Industry (Surface Coating)

Agricultural Production

Air, Water, & Solid Waste Management

Aircraft Manufacturing

Aircraft Parts and Equipment Manufacturing

Aircraft And Parts

Airports, Flying Fields, & Services

Aluminum Extruded Products

Aluminum Foundries

Aluminum Foundries (Castings)

Aluminum Die-Castings

Ammunition, Except for Small Arms

Amusement Parks

Animal Cremation

Asphalt Production

Asphalt Roofing Production

Asphalt Paving Mixtures And Blocks

Automotive stampings

Ball and Roller Bearings Manufacturing

Beet Sugar

Black Liquor Combustion

Blast Furnaces and Steel Mills

Boat Building and Repairing

Bolts, Nuts, Rivets and Washers Manufacturing

Brick and Structural Clay Tile

Cadmium Stabilizers for Plastics

Canned specialties

Canned Fruits and Vegetables

Carbon Black Manufacture

Cement, Hydraulic (not subject to Portland Cement Regulation)

Chemical Preparations

Chemical Manufacturing: Cyclic Crude and Intermediate 

Production

Chromium Plating: Chromic Anodizing Plating

Chromium Metal Plating

Coated Fabrics, not Rubberized, Manufacturing

Commercial Physical Research

Commercial Printing, Letterpress, and Screen

Commercial Printing, Lithographic

Commercial Printing, nec

Commercial/Institutional Boilers: Coal Combustion, all types

Commercial/Institutional Heating: Anthracite Coal Combustion

Commercial/Institutional Heating: Bituminous and Lignite Coal 

Combustion

Commercial/Institutional Heating: Distillate Oil Combustion

Commercial/Institutional Heating: Natural Gas Combustion

Commercial/Institutional Heating: Residual Oil Combustion

Commercial/Institutional Heating: Wood/Wood Residue

 Combustion
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page B-5

CADMIUM AND COMPOUNDS (CONTINUED)

Confectionery

Construction Machinery Manufacturing

Construction Sand And Gravel

Construction (SICs 15-17)

Copper Rolling and Drawing

Correctional Institutions

Cotton

Cottonseed Oil Mills

Courts

Crop Services

Crop Preparation Services For Market

Crude petroleum and natural gas

Crude Petroleum Pipelines

Crushed And Broken Limestone

Crushed And Broken Stone, Nec

Crushed And Broken Granite

Custom Compound Purchased Resins Manufacturing

Dehydrated fruits, vegetables, and soups

Depository Institutions

Durable Goods, Nec

Electric and other services combined

Electric services

Electron Tubes Manufacturing

Electronic Computers

Electronic Connectors

Electronic Components, nec

Engine Electric Equipment

Engineering Services

Environmental Controls Manufacturing

Fabricated Structural Metal Manufacturing

Fabricated Metal Products, nec

Ferroalloy Ores, Except Vanadium

Flat Glass

Flour and other grain mill products

Fluid power Valves and Hose Fittings Manufacturing

Food and Agricultural Products: Cotton Ginning

Frozen fruits, fruit juices and vegetables

Funeral Service And Crematories

Gas And Other Services Combined

General Medical & Surgical Hospitals

Glass Containers

Gold Ores

Gray and Ductile Iron Foundries

Grocery Stores

Guided Missiles and Space Vehicles Manufacturing

Halogenated Solvent Cleaners

Hardware Manufacturing

Heating Equipment, Except Electric

Heavy Construction, Nec

Hospitals

Hotels And Motels

Household Cooking Equipment

Human Cremation

Hydrochloric Acid Production

Industrial Boilers: Bituminous and Lignite Coal Combustion

Industrial Boilers: Anthracite Coal Combustion

Industrial Boilers: Coal, all types

Industrial Boilers: Distillate Oil Combustion

Industrial Boilers: Natural Gas Combustion

Industrial Boilers: Residual Oil Combustion

Industrial Boilers: Waste Oil Combustion

Industrial Boilers: Wood/Wood Residue Combustion

Industrial machinery and equipment

Industrial Machinery, nec

Industrial Organic Chemicals Manufacturing

Industrial Sand

Industrial/Utility Dist. Oil/Diesel Turbines

Inorganic Pigments Manufacturing (Cadmium only)

Instruments to Measure Electricity

Intercity & Rural Bus Transportation

Internal Combustion Engine Manufacturing

Iron and Steel Foundries: Steel Foundries

Iron and Steel Forging

Lead Pencils, Art Goods Manufacturing

Life Insurance

Lighting Equipment

Lightweight Aggregate Kilns

Lime

Lubricating Oils and Greases

Malt Beverages

Manufacturing Industries Manufacturing

Marine Cargo Handling

Metal coating and allied services (3479)

Metal Heat Treating Manufacturing

Metal Sanitary Ware Manufacturing

Metal cans (3411)

Mineral Wool

Mineral Wool Manufacturing (includes Wool Fiberglass)

Minerals, Ground or Treated Production

Miscellaneous Nonmetallic Minerals

Miscellaneous Metal Work

Mobile Sources: On- Road Vehicles

Mobile Sources: Non-Road Vehicles and Equipment - 

Commercial Marine Vessels

MON - Continuous Processes

Motion Picture & Video Production

Motor and Generators Manufacturing

Motor Vehicle Parts and Accessories Manufacturing

National Security

Natural Gas Liquids

Non-road Mobile Vehicles

Non-stainless Steel Manufacture - EAF

Noncommercial research organizations (1987)

Nonferrous Wire Drawing and Insulating

Nonferrous Rolling and Drawing

Nonferrous Foundries, nec

Nonmetallic Mineral Products Manufacturing

Nursing And Personal Care, Nec

Oil And Gas Field Services, Nec

On-Site Waste Incineration

Ordnance and Accessories Manufacturing

Ornamental Nursery Products

Other Cadmium Compound Production

Other Structural Clay Products

Paints and Allied Products Manufacturing

Paved Road Dust

Petroleum Refining

Petroleum Bulk Stations and Terminals

Petroleum Refining

Petroleum Refining: Other Petroleum Products

Pharmaceutical Preparations Manufacturing

Plastics Materials and Resins Manufacturing

Plastics Products Manufacturing

Plastics Foam Products Manufacturing

Portland Cement Manufacture: All Fuels

Prepackaged Software

Prepared Feeds Manufacturing

Pressed and Blown Glass and Glassware Manufacturing
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Page B-6 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

CADMIUM AND COMPOUNDS (CONTINUED)

Primary Copper

Primary Batteries, Dry and Wet, Manufacturing

Primary Metal Products Manufacturing

Pulp mills (2611)

Pulp and Paper: Kraft Recovery Furnaces

Radio and Television Communications Equipment (3663)

Railroads, Line-haul Operating

Raw cane sugar

Ready-mixed Concrete

Refrigeration and Heating Equipment Manufacturing

Refuse Systems

Repair services, nec

Residential Bituminous and Lignite Coal Combustion

Residential Care

Residential Distillate Oil Combustion

Residential lighting fixtures

Residential Anthracite Coal Combustion

Residential Wood/Wood Residue Combustion

Rice Milling

Sawmills and Planing Mills, general

Schools & Educational Services, Nec

Scrap And Waste Materials

Screw Machine Products, Bolts, etc.

Search and Navigation Equipment

Secondary Aluminum Smelting

Secondary Nonferrous Metals Production

Secondary Zinc Production

Semiconductors and Related Devices

Service Industry Machinery

Sewerage Systems

Sheet Metal Work

Ship Building And Repairing

Skilled Nursing Care Facilities

Soap and Other Detergents Manufacturing

Soil Dust

Space Research and Technology

Space Propulsion Units and Parts Manufacturing

Specialty Hospitals Exc. Psychiatric

Stainless Steel Manufacture - EAF

Stationary IC Engines - Diesel

Stationary IC Engines - Natural Gas

Steam And Air-conditioning Supply

Storage Batteries Manufacturing

Structural Clay Products, nec

Telephone and Telegraph Apparatus

Tire Manufacturing

Tires and Inner Tubes

Top & body repair and paint shops (1987)

Travel Trailers and Campers Manufacturing

Trucking, Except Local

Turbines and Turbine Generator Sets

Turbines - Natural Gas

Unpaved Road Dust

Unsupported Plastics Film & Sheet

Utility Boilers: Coal Combustion, all types

Utility Boilers: Coke

Utility Boilers: Natural Gas Combustion

Utility Boilers: Oil Combustion, all types

Valves and Pipe Fittings Manufacturing

Water supply

Wood Products

DIOXINS AND FURANS (MEASURED AS 2,3,7,8-TCDD TEQ)

 

Carbon Reactivation Furnaces

Commercial/Institutional Heating: Anthracite Coal Combustion

Commercial/Institutional Heating: Bituminous and Lignite Coal 

Combustion

Commercial/Institutional Heating: Wood/Wood Residue 

Combustion

Drum and Barrel Reclamation

Hazardous Waste Incineration

Industrial Boilers: Anthracite Coal Combustion

Industrial Boilers: Bituminous and Lignite Coal Combustion

Lightweight Aggregate Kilns

Portland Cement Manufacture: Hazardous Waste-fired

Pulp and Paper: Kraft Recovery Furnaces

Residential Bituminous and Lignite Coal Combustion

Residential Anthracite Coal Combustion

Scrap Tire Combustion

Secondary Copper Smelting

Secondary Lead Smelting

Sewage Sludge Incineration

Utility Boilers: Coke

POLYCYCLIC AROMATIC HYDROCARBONS (MEASURED AS 16-PAH)

Abrasive Products

Adhesives and Sealants

Agricultural Chemicals and Pesticides

Aircraft Parts and Equipment Manufacturing

Aircraft Manufacturing

Aluminum Extruded Products

Aluminum Foundries

Aluminum Sheet, Plate, and Foil manufacturing

Animal Cremation

Asphalt Felts And Coatings

Asphalt Paving Production

Blast Furnaces and Steel Mills

Carbamate Insecticides Production

Carbon and Graphite Products

Cement, Hydraulic (not subject to Portland Cement Regulation)

Chemical Manufacturing: Naphthalene

Chemical Manufacturing: Alkalies and Chlorine

Chemical Manufacturing: Cyclic Crude and Intermediate 

Production

Chemical Manufacturing: Naphthalene Sulfonates

Chemical Preparations

Cigarette Smoke

Clay Refractories

Coke Ovens: By-product Recovery Plants

Cold Finishing of Steel Shapes

Commercial/Institutional Heating: POTW Digester Gas 

Combustion

Commercial Physical Research

Commercial Printing, Gravure

Commercial Printing, Letterpress, and Screen
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page B-7

POLYCYCLIC AROMATIC HYDROCARBONS (MEASURED AS 16-PAH) (CONTINUED)

Commercial/Institutional Heating: Anthracite Coal Combustion

Commercial/Institutional Heating: Bituminous and Lignite Coal 

Combustion

Commercial/Institutional Heating: Distillate Oil Combustion

Commercial/Institutional Heating: Natural Gas Combustion

Commercial/Institutional Heating: Residual Oil Combustion

Commercial/Institutional Heating: Wood/Wood Residue 

Combustion

Construction Machinery Manufacturing

Drum and Barrel Reclamation

Fabric Dress and Work Gloves

Fabricated Plate Work (Boiler Shops)

Fabricated Metal Products, nec

Fabricated Rubber Products, nec

Fabricated Structural Metal Manufacturing

Ferroalloy Manufacture

Fiber Cans, Drums, and Similar Products

Gray and Ductile Iron Foundries

Gum and Wood Chemical Manufacturing

Hard Surface Floor Coverings Manufacturing

Household Cooking Equipment

Household Appliances Manufacturing

Human Cremation

Hydrochloric Acid Production

Industrial Boilers: Waste Oil Combustion

Industrial Boilers: Anthracite Coal Combustion

Industrial Boilers: Bituminous and Lignite Coal Combustion

Industrial Boilers: Distillate Oil Combustion

Industrial Boilers: Natural Gas Combustion

Industrial Boilers: Residual Oil Combustion

Industrial Boilers: Wood/Wood Residue Combustion

Industrial Gases Manufacturing

Industrial Inorganic Chemical Manufacturing

Integrated Iron and Steel Mills

Internal Combustion Engine Manufacturing

Landfills: Gas Flares

Lubricating Oils and Greases

Manufacturing Industries Manufacturing

Meat Packing Plants

Medical Waste Incineration

Medicinals and Botanicals Manufacturing

Metal Barrels, Drums, and Pails Manufacturing

Metal Coil (Surface Coating)

Metal Doors, Sash, and Trim

Metal Household Furniture

Miscellaneous Plastics Products

Miscellaneous Chemical Products (2890)

Mobile Sources: Non-Road Vehicles and Equipment - Aircraft

Mobile Sources: Non-Road Vehicles and Equipment - 

Commercial Marine Vessels

Mobile Sources: Non-Road Vehicles and Equipment - Other

Mobile Sources: On- Road Vehicles

Motor Vehicle Equipment

Motor Vehicles and Car Bodies Manufacturing

Municipal Waste Combustion

Naphthalene: Miscellaneous Uses

Needles, Pins, Hooks and Eyes and Similar Notions

Non-stainless Steel Manufacture - EAF

Nonferrous Wire Drawing and Insulating

Nonmetallic Mineral Products Manufacturing

Office Furniture, Except Wood Manufacturing

Oil and Gas Field Machinery Manufacturing

Other Structural Clay Products

Paints and Allied Products Manufacturing

Paper Coated and Laminated, Packaging, nec

Paper Mills

Partitions and Fixtures, Except Wood

Petroleum Bulk Stations and Terminals

Petroleum Refining

Pharmaceutical Preparations Manufacturing

Phthalic Anhydride Production

Plastics Materials and Resins Manufacturing

Plastics Foam Products Manufacturing

Polishes and Sanitation Goods Manufacturing

Potato Chips and Similar Snacks

Primary Nonferrous Metals Production

Public Building and Related Furniture

Publicly Owned Treatment Works (POTWs)

Refrigeration and Heating Equipment Manufacturing

Residential Anthracite Coal Combustion

Residential Bituminous and Lignite Coal Combustion

Residential Distillate Oil Combustion

Residential Natural Gas Combustion

Residential Wood/Wood Residue Combustion

Scrap Tire Combustion

Secondary Lead Smelting

Sewage Sludge Incineration

Sheet Metal Work

Ship Building & Repair

Soap and Other Detergents Manufacturing

Sporting and Athletic Goods Manufacturing

Stainless Steel Manufacture - EAF

Stationary IC Engines - Diesel

Stationary IC Engines - Natural Gas

Surface Active Agents Manufacturing

Tire Manufacturing

Transformers, Except Electronic

Truck and Bus Bodies

Turbines - Natural Gas

Utility Boilers: Coke

Utility Boilers: Coal Combustion, all types

Utility Boilers: Natural Gas Combustion

Utility Boilers: Oil Combustion, all types

Wood Household Furniture Manufacturing

Wood Treatment/Wood Preserving

Yarn Spinning Mills
Appendix B

Detailed Breakdown of Air Emissions Inventory by Pollutant for Source Categories Emitting Less

than 1 Percent of Total U.S. Emissions

Page B-8 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

POLYCHLORINATED BIPHENYLS

 

Adhesives and Sealants

Air, Water, & Solid Waste Management

Animal Cremation

Commercial Printing, Lithographic

Electric services

Industrial Boilers: Wood/Wood Residue Combustion

Landfills: Gas Flares

Minerals, Ground or Treated Production

Petroleum Refining

Secondary Nonferrous Metals Production

 Services, Nec
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page C-1

APPENDIX C

Fish Consumption Advisories Issued for the Great Waters 

Waterbody PCBs Dioxins Hg Cadmium Chlordane Toxaphene Mirex DDT Dieldrin Kepone Others

Great Lakes

Lake Superior ! ! ! !

Lake Michigan ! ! !

Lake Huron ! ! !

Lake Erie !

Lake Ontario ! ! !

Other Great Waters

Chesapeake Bay

Potomac River a ! ! !

James River a !

Back River a !

Baltimore Harbor a !

Anacostia River a ! !

Lake Champlain, NY ! !

NEP and NERR Sites

Casco Bay, ME (NEP) !

Wells, ME (NERR) !

Great Bay, NH (NERR) !

Great Bay, Little Bay, and

Hampton Harbor, NH (NEP) !

Massachusetts Bays, MA

(NEP) ! !

b

Buzzards Bay, MA (NEP) ! !
Appendix C

Fish Consumption Advisories Issued for the Great Waters

Waterbody PCBs Dioxins Hg Cadmium Chlordane Toxaphene Mirex DDT Dieldrin Kepone Others

Page C-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

Waquoit Bay, MA (NERR) !

Narragansett Bay, RI (NEP) 

(NERR) !

Long Island Sound, NY/CT

(NEP) ! ! !

Peconic Bay, NY (NEP) ! ! !

Hudson River, NY (NERR) ! !

New York/New Jersey Harbor

(NEP) ! ! ! !

Barnegat Bay, NJ (NEP) !

Jacques Cousteau-Great Bay

and Mullica River, NJ (NERR) !

Old Woman Creek, OH

(NERR)

Delaware Estuary, DE/NJ/PA

(NEP) (NERR) ! ! ! !

Delaware Inland Bays, DE

(NEP)

Maryland Coastal Bays, MD

(NEP) (includes Assawoman,

Isle of Wight, Sinepuxent,

Newport, and Chincoteague

Bays)

Chesapeake Bay, MD (NERR)

Chesapeake Bay, VA (NERR)

Albemarle-Pamlico Sounds,

NC (NEP) !

NC Coastal sites (NERR)

(4 reserves)
Appendix C

Fish Consumption Advisories Issued for the Great Waters

Waterbody PCBs Dioxins Hg Cadmium Chlordane Toxaphene Mirex DDT Dieldrin Kepone Others

Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page C-3

North Inlet/Winjah Bay, SC 

(NERR)

Ashepoo-Combahee-Edisto

Basin, SC (NERR) !

Sapelo Island, GA (NERR)

Indian River Lagoon, FL

(NEP) !

San Juan Bay, PR (NEP)

Jobos Bay, PR (NERR)

Charlotte Harbor, FL (NEP) !

Rookery Bay, FL (NERR) !

Sarasota Bay, FL (NEP) !

Tampa Bay, FL (NEP) !

Apalachicola Bay, FL (NERR) !

Mobile Bay, AL (NEP) !

Weeks Bay, AL (NERR) !

Barataria-Terrebonne

Estuarine Complex, LA (NEP) !

Galveston Bay, TX (NEP) ! !

Corpus Christi Bay, TX (NEP) !

Kachemak Bay, AK (NERR)

Padilla Bay, WA (NERR)

Puget Sound, WA (NEP) ! ! ! !

 c

Columbia River, OR/WA

(NEP) ! ! !

Tillamook Bay, OR (NEP)
Appendix C

Fish Consumption Advisories Issued for the Great Waters

Waterbody PCBs Dioxins Hg Cadmium Chlordane Toxaphene Mirex DDT Dieldrin Kepone Others

Page C-4 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

South Slough, OR (NERR)

San Francisco Bay, CA (NEP) ! ! ! ! ! ! !

d

Elkhorn Slough, CA (NERR)

Morro Bay, CA (NEP)

Santa Monica Bay, CA (NEP) ! !

Tijuana River, CA (NERR)

a Major tributary rivers to the Chesapeake Bay

b Multiple pollutants (unspecified)

c

 Specific embayments of Puget Sound are listed for the following pollutants; creosote, pentachlorophenol, volatile organic compounds (VOCs),

tetrachloroethylene, arsenic, metals (unspecified), vinyl chloride, polyaromatic hydrocarbons (PAHs), polynuclear aromatics, and pesticides (unspecified).

d

 Other unspecified pesticides.

Note: Shading is used in rows to designate waters where no advisories were in effect as of December 31, 1997. 

Source: U.S. EPA 1998m (Advisories current through December 31, 1997).
Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000 Page D-1

APPENDIX D

Names of Numbered Sites from Figure II-17: 

Locations of Watersheds Designated as Areas of

Probable Concern 

Map # Watershed Name Map # Watershed Name

1 Charles 49 Watts Bar Lake

2 Cape Cod 50 Lower Clinch

3 Narragansett 51 Middle Tennessee-Chickamauga

4 Hackensack-Passaic 52 Hiwassee

5 Sandy Hook-Staten Island 53 Guntersville Lake

6 Raritan 54 Pickwick Lake

7 Southern Long Island 55 Lower Tennessee-Beech

8 Middle Delaware-Musconetcong 56 Kentucky Lake

9 Lower Delaware 57 Twin Cities

10 Schuylkill 58 Rush-Vermillion

11 Mullica-Toms 59 Buffalo-Whitewater

12 Gunpowder-Patapsco 60 Castle Rock

13 Conococheague-Opequon 61 Copperas-Duck

14 Lower Pee Dee 62 Kishwaukee

15 Seneca 63 Chicago

16 Middle Savannah 64 Des Plaines

17 Lower St. Johns 65 Upper Fox

18 Middle Chattahoochee-Lake Harding 66 Lower Illinois-Senachwine Lake

19 Choctawhatchee Bay 67 Cahokia-Joachim

20 Perdido Bay 68 Big Muddy

21 Mobile Bay 69 Upper Kaskaskia

22 Door-Kewaunee 70 Middle Kaskaskia

23 Menominee 71 Lower Mississippi-Memphis

24 Lower Fox 72 Deer-Steele

25 Little Calumet-Galien 73 Lower Ouachita

26 Pike-Root 74 Lower Calcasieu

27 Milwaukee 75 Lower Mississippi-New Orleans

28 St. Joseph 76 Lower Kansas
Appendix D

Names of Numbered Sites from Figure II-16:

Locations of Watershed Designated as Areas of Probable Concern

Map # Watershed Name Map # Watershed Name

Page D-2 Deposition of Air Pollutants to the Great Waters – 3rd Report to Congress 2000

29 Manistee 77 Spring

30 Lake St. Clair 78 Lower Neosho

31 Detroit 79 Buffalo-San Jacinto

32 Ottawa-Stony 80 Coeur D’Alene Lake

33 Raisin 81 Lower Yakima

34 Cedar-Portage 82 Lower Willamette

35 Huron-Vermillion 83 Strait of Georgia

36 Black-Rocky 84 Duwamish

37 Ashtabula-Chagrin 85 Puyallup

38 Chautauqua-Conneaut 86 Puget Sound

39 Buffalo-Eighteenmile 87 Tulare-Buena Vista Lakes

40 Niagara 88 Coyote

41 Oak Orchard-Twelvemile 89 San Francisco Bay

42 Upper St. Lawrence 90 Santa Monica Bay

43 Upper Ohio 91 Los Angeles

44 Shenango 92 San Pedro Channel Islands

45 Tuscarawas 93 Seal Beach

46 Vermilion 94 Newport Bay

47 Middle Wabash-Busseron 95 Aliso-San Onofre

48 Holston 96 San Diego

Source: U.S. EPA 1997i