United States Office of Air Quality EPA-453/R-97-011
Environmental Protection Planning and Standards June 1997
Agency Research Triangle Park, NC 27711
SEPA Deposition of Air Pollutants
to the Great Waters
Second Report to Congress
Printed on Recycled Paper
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ACKNOWLEDGEMENTS
This report was prepared by the U.S. Environmental Protection Agency's (EPA's) Office of
Air Quality Planning and Standards (OAQPS).
EPA wishes to thank the authors for the time and effort they spent preparing and reviewing
the drafts of the document. The lead contributors to the writing, editing, and review of this
document were members of the OAQPS's Great Waters Team: John Ackermann, Melissa
McCullough, Eric Ginsburg, Dianne Byrne, and Laurel Driver. Recogni2ing the breadth of the task
of preparing this report, OAQPS worked with individuals in EPA offices to coordinate input into
the report. These individuals represent the "Great Waters Core Group" and include the following
individuals: Angela Bandemehr, Rich Batiuk, Gary Evans, Jim Giattina, Martha Keating, Maggie
Kerchner, Virginia Kibler, Carl Nash, Doris Price, Roy Smith, and Joe Touma.
In addition, substantial review of the document also was provided by the following EPA
offices:
Chesapeake Bay Program Office Office of Policy, Planning and Evaluation
Gulf of Mexico Program Office Office of Research and Development
Great Lakes National Program Office Office of Water
National Health and Environmental Effects Region II
Research Laboratory Region V
Office of Air and Radiation
The following organi2ations also have been included in review of the document:
Atmospheric Environment Service, Environment Canada
Centre for Atmospheric Research Experiments, Environment Canada
Department of Commerce/National Oceanic and Atmospheric Administration (NOAA)
Environmental Defense Fund
Maine Department of Environmental Protection
Michigan Department of Environmental Quality
Wisconsin Department of Natural Resources
Wisconsin Electric Power Company and Electric Power Research Institute
In addition, this document was reviewed by a panel of external scientific experts whose
constructive comments provided critical assistance in improving the scientific perspective of the
final report. These experts include:
Dr. Anders W. Andren Sea Grant Institute, University of Wisconsin-Madison
Dr. William F. Fit2gerald Department of Marine Sciences, University of Connecticut
Dr. Louis J. Guillette Jr. Department of Zoology, University of Florida
Dr. Hans W. Paerl Institute of Marine Sciences, University of North Carolina
The following individuals also provided specific comments on the draft document:
Mary Ann Allan, Richard Artz, Terry F. Bidleman, Rona Birnbaum, Marty Burkholder, David
Cleverly, Ellen Cooler, Carolyn Currin, Stan Durkee, David W. Evans, Theresa Faber, Peter
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Finkelstein, Jim Galloway, Ellen Heath, Steven F. Hedtke, Roland Hemmett, Bruce Hicks, Raymond
M. Hoff, Su2anne King, Peter Landrum, Nancy Laurson, Su2anne McMaster, David T. Michaud,
Todd Nettesheim, Ellen E. Parr Doering, Jon Taylor, Mike Thrift, Rick Tonielli, and Richard
Valigura.
Technical support in preparing this document has been provided by ICF Kaiser under EPA
Contract Nos. 68D4-0103 and 68D6-0064. The efforts of Karen Gan and Anne Cowan are
especially appreciated.
Appreciation is given to all others who have contributed to this report and were
inadvertently not mentioned above.
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EXECUTIVE SUMMARY
This report is the Second Report to Congress on the atmospheric deposition of pollutants to
the Great Waters. Section 112 of the Clean Air Act (CAA) provides the legislative basis for
ha2ardous air pollutant (HAP) programs directed by the U.S. Environmental Protection Agency
(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 CAA.
Under this statute, EPA is required to periodically report to Congress on the results of this program.
Concurrent with the Second Report to Congress, EPA is to determine the adequacy of section 112
to prevent adverse effects to public health and serious or widespread environmental effects
associated with atmospheric deposition of HAPs to the Great Waters.
How does this report differ from the 1994 Report to Congress?
The First Report to Congress presented information about the health and environmental
effects associated with the pollutants of concern, relative atmospheric loadings, and the potential
sources of these loadings. The current report documents findings since the First Report to Congress
and describes recent progress in these issues. This report places emphasis on local and federal
activities, including many that support section 112(m) directives, taking place at specific waterbodies
such as the Great Lakes, Lake Champlain, and Chesapeake Bay, as well as coastal estuaries
designated through the National Estuary Program and National Estuarine Research Reserve System.
Due to the short time period since the First Report to Congress, much of the research data collected
during this time are still in the process of being analyzed; however, the objectives and status of these
efforts are described in the report. Furthermore, this report does not assess the linkage between the
potential sources, loadings, and effects of pollutants of concern because, as in the First Report to
Congress, the scientific information is currently not sufficiently complete. As such, unanswered
questions still remain as well as uncertainties for some issues. This report proposes a number of
future directions to reduce uncertainty in several areas.
Because this report is an update of the First Report to Congress, the information presented
here cannot be used alone to develop recommendations regarding atmospheric deposition of
pollutants to the Great Waters. Rather, the scientific information summarised in this report,
together with the findings and recommendation identified in the First Report to Congress, can be
used to assess the extent of progress as a result of recommendations from the First Report to
Congress and to determine what gaps in information still exist.
Has the list of Great Waters pollutants of concern changed?
The pollutants of concern to the Great Waters have not changed since the First Report to
Congress. The list consists of 15 pollutants (see sidebar on next page) including pesticides, metal
compounds, chlorinated organic compounds, and nitrogen compounds. These pollutants have been
selected based on information regarding their health and environmental effects and evidence that
they are atmospherically deposited to the Great Waters. Most are bioaccumulative chemicals that
persist in the environment for long periods. Many of these pollutants are listed as chemicals of
concern on toxics lists for individual waterbodies at the local and statewide level.
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EXECUTIVE SUMMARY
What are the environmental and
public health effects of the
pollutants of concern to the Great
Waters?
Recent scientific information confirms
adverse effects data presented in the First
Report. The pollutants are associated with
deleterious effects on many target organs in
humans and animals, including the liver, kidney,
nervous system, endocrine system, reproductive
organs, and immunological system. Few new
developments have occurred in this area,
although there is a growing interest about the
potential for some pollutants to act on and
disrupt the endocrine system in wildlife and
possibly in humans.
The 15 Great Waters
Pollutants of Concern
Cadmium and cadmium compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene (HCB)
a-Hexachlorocyclohexane (a-HCH)
Lindane (y-hexachlorocyclohexane; y-HCH)
Lead and lead compounds
Mercury and mercury compounds
Polychlorinated biphenyls (PCBs)
Polycyclic organic matter (POM)
Tetrachlorodibenzo-p-dioxin (TCDD; dioxins)
Tetrachlorodibenzofuran (TCDF; furans)
Toxaphene
Nitrogen compounds
As in the First Report to Congress, the contribution of atmospheric deposition of the
pollutants and subsequent exposure to potential human health and ecological effects cannot be
quantified at this time. Pollutants deposited from the air directly into a waterbody may have routes
of exposure to aquatic life that differ from exposure by waterborne inputs; however, there are few
studies available to address this issue. There is currently no information to suggest that effects
produced by pollutants deposited from the air will be different from effects by these pollutants
carried in water or found in sediment. Contamination in fish can enter the diet of humans and other
animals and, therefore, fish-eating birds or mammals are especially at risk from pollutants that
biomagnify because they are exposed to concentrated levels of these pollutants. Evaluation of
potential human health effects of pollutants of concern is based almost completely on laboratory
studies in animals. The data from these studies may be extrapolated to assess potential adverse
effects in humans; however, uncertainties may exist as to the exposure levels at which these potential
effects may occur. Atmospheric deposition of nitrogen compounds can contribute significantly to
eutrophication in coastal waters, where plant productivity is usually limited by nitrogen availability.
Accelerated eutrophication and its subsequent effects such as nuisance algal blooms and reduced
oxygen levels pose significant problems for Chesapeake Bay and many other estuaries.
Do water quality exceedances or fish advisories continue to occur as a result
of pollution loadings to the Great Waters?
Current water quality criteria exceedances and fish advisories suggest that toxic
contamination by persistent toxics is present in the Great Waters. The contribution of atmospheric
deposition to the water quality exceedances and contaminant levels in fish is not known at this time.
More information on relative loadings of pollutants is needed to assess the extent of contamination
attributed to atmosphere.
Water quality criteria have been developed specifically for the Great Lakes, and exceedances
of these criteria continue to occur. Recent information is available for some pollutants, and in
general, these exceedances have declined in recent years. Fish advisories that are issued by states for
individual pollutants provide qualitative information about potential exposure and the extent of
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EXECUTIVE SUMMARY
contamination in a waterbody. PCBs are most commonly the focus of fish advisories issued in the
Great Waters and their basins, with dioxins having the next highest occurrence of advisories.
Elevated levels in fish of other pollutants, such as chlordane and mercury, also have warranted fish
advisories in many states around the Great Waters.
What is currently known about the atmospheric deposition of the pollutants
of concern to the Great Waters?
The contribution of atmospheric deposition to overall pollutant loadings in the Great Waters
continues to be studied. Atmospheric loadings of pollutants result from wet deposition and dry
particle deposition and through air-water gas exchange. Described in this report are monitoring and
modeling studies relevant to atmospheric deposition that are currently taking place at the major
waterbodies of the Great Waters.
Recent atmospheric monitoring data from a binational monitoring network assessing trends
of atmospheric deposition to the Great Lakes region indicate that atmospheric levels of toxic
pollutants are declining slightly or leveling off and remain a significant concern in the Great Lakes.
Several recent activities in the Great Lakes have been initiated to characteri2e and reduce toxic
contamination and deposition to these waters. In the Lake Champlain basin, research on
atmospheric loading of mercury is currently underway in the basin. Early data show that
atmospheric mercury levels and deposition are comparable to those measured around the Great
Lakes.
Nitrogen and toxic contaminants are a concern in Chesapeake Bay and other coastal waters.
Excessive nitrogen loading can accelerate eutrophication and its adverse effects, such as nuisance
algal blooms and fish kills. Substantial progress has been made in addressing nitrogen
contamination issues in Chesapeake Bay, the largest U.S. estuary. A strategy has been developed by
the Chesapeake Bay Program for reducing the nitrogen load to the Bay. Part of this process
includes the large-scale modeling and understanding of the type and geographic origin of airborne
nitrogen to the Bay. Significant data also have been collected on rates and amounts of nitrogen
deposition (including comparison of direct and indirect deposition and of wet and dry deposition),
and models have been developed to evaluate the impact of several nitrogen reduction scenarios on
the Bay's water quality.
Since the First Report to Congress, studies of other coastal waters, at National Estuary
Program waters in particular, have investigated the significance of atmospheric deposition of
nitrogen compounds to their waters. To improve understanding and reduction of nitrogen
deposition to Chesapeake Bay and other coastal waters, the Chesapeake Bay Program, various
National Estuary Programs, and the Gulf of Mexico Program continue to develop and refine
modeling and monitoring efforts by addressing uncertainties such as nitrogen retention in
watersheds, the differences in transport and fate of various nitrogen compounds, and the
contribution of nearshore ocean waters to the nitrogen inputs to estuaries.
What is currently known about the sources of atmospheric pollutant
deposition to the Great Waters?
Both local and long-range emission sources contribute to atmospheric deposition in the
Great Waters. Emission inventories on specific sources of the pollutants of concern are actively
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EXECUTIVE SUMMARY
being developed and efforts to gather more information on the potential sources of contamination
continue. For example, EPA recently completed a national emissions inventory of known U.S.
sources of seven ha2ardous pollutants of concern listed under CAA section 112(c)(6). Identification
of the sources for total emissions of these pollutants is leading to an evaluation of the stationary,
anthropogenic source categories to determine whether they are currently regulated or scheduled for
regulation under the CAA. Some persistent pollutants are no longer produced through human
activities but may continue to affect the Great Waters environment through releases from existing
equipment and repeated cycling between the atmosphere, land, and waterbodies.
Understanding atmospheric processes is necessary for analyzing the relationships between
source emissions, relative loadings, and the potential for adverse effects in humans and the
environment. Because it is often difficult to establish these relationships clearly and quantitatively
through available measurement data (e.g., it can be difficult to differentiate between the contribution
of distant versus local sources to the loading of a pollutant to a particular waterbody), investigators
frequently use mathematical models of atmospheric transport and deposition. This report presents
the application of several atmospheric transport and deposition models to the Great Waters and
how these models compared to actual data from the waterbodies. Extensive modeling of nitrate
emissions and transport that can deposit to Chesapeake Bay has calculated the "airshed" of distant
as well as local sources.
What are EPA's current conclusions from this Second Report to Congress?
The information presented in this report advances scientific knowledge on issues related to
atmospheric deposition of pollutants to the Great Waters and confirms the findings and conclusions
presented in the First Report to Congress. In general, concentrations of some persistent pollutants
in the Great Lakes, as monitored by sample measurements of contaminant levels in the air, water,
and biota, appear to have leveled off or declined only slightly in recent years.
EPA also has issued draft determinations that the provisions of CAA section 112 are
adequate to prevent serious adverse human health effects and serious or widespread environmental
effects as a result of atmospheric deposition of HAPs emitted by domestic stationary sources. At
this time, EPA believes that there is no information to suggest that additional regulations beyond
those authori2ed or required by section 112 are necessary or appropriate to prevent such effects.
The draft determinations will be issued for public notice and comment by June 30, 1997, and final
determinations will be made by March 15, 1998.
What future directions may be taken by EPA to support section 112(m)?
Described throughout the report are activities that have increased our knowledge of
atmospheric deposition of pollutants to the Great Waters. As new information becomes available on
atmospheric pollutant deposition to the Great Waters, additional questions or issues are expected to
arise that will require further investigation or action. At this time, EPA has identified the following
areas where information is limited and some specific steps that need to be taken to advance our
understanding of issues relevant to the Great Waters program:
• Define and proceed with management and regulatory actions for Great Waters
pollutants of concern, with a particular focus given to pollutants currently being
emitted to the air from sources that can be subject to regulations under the CAA (for
example, the seven pollutants of concern in section 112(c)(6));
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EXECUTIVE SUMMARY
Continue to support monitoring and research efforts on deposition to make
informed management decisions and to track reductions;
Perform exposure and effects studies that will build on the recent Great Lakes Water
Quality Criteria, which consider biomagnification. These studies will be coordinated
with an integrated research strategy on the persistent pollutants, their distribution
and concentrations, exposure routes, and associated effects;
Improve modeling efforts to estimate atmospheric loadings to Great Waters. For
example, adapt and apply the comprehensive approach developed for the Lake
Michigan Mass Balance Model to additional waterbodies;
Increase efforts to identify specific emissions sources of atmospheric deposition to
the Great Waters, both nearby and relatively distant from the waterbody, to develop
risk management strategies, as well as investigate the impact from cycling of
pollutants that are no longer used or manufactured in the United States;
Continue to promote pollution reduction in the Great Waters through local, regional,
and federal initiatives, as well as coordinated international efforts; and
Assess economic costs and benefits associated with reductions of pollutants to the
Great Waters, including identifying and quantifying, where possible, economic
impacts associated with exposure and effects indicators such as fish advisories,
habitat decline, diminished species diversity, fish kills, and declining or contaminated
shellfish and fish populations.
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TABLE OF CONTENTS
PAGE
EXECUTIVE SUMMARY i
LIST OF TABLES xi
LIST OF FIGURES xii
LIST OF ABBREVIATIONS AND ACRONYMS xiii
I. OVERVIEW OF THE GREAT WATERS PROGRAM 1
A. The Second Report to Congress 2
Goals of the Report 2
Report Preparation 2
B. The First Report to Congress 4
C. Highlights of Progress Since the First Report to Congress 6
D. Pollutants of Concern 7
Great Waters Pollutants of Concern and Reasons for Inclusion 7
Use of Pollutant Groups 11
Relationship of Pollutants of Concern to Section 112 and Other CAA Requirements .... 13
II. EXPOSURE AND EFFECTS 15
A. Exposure Routes and Extent of Contamination 17
Conclusions from the First Report to Congress 17
Current Understanding of Exposure Routes and Extent of Contamination 19
B. Contamination of Biota 27
Sampling Biota for Contamination 27
Biota Contamination by Major Waterbody 32
C. Ecological Effects 39
Conclusions from the First Report to Congress 39
Current Understanding of Ecological Effects 41
D. Human Health Effects 55
Conclusions from the First Report to Congress 55
Current Understanding of Human Health Effects 56
E. Other Effects 67
Environmental Justice Concerns 67
Commercial and Recreational Fishing Losses 69
Other Recreational Losses 69
III. ATMOSPHERIC TRANSPORT AND DEPOSITION PROCESSES 71
A. Atmospheric Deposition and Environmental Cycling 71
Wet Deposition 72
Dry Deposition 73
Gas Exchange Across the Air-Water Interface 74
Environmental Cycling of Semi-Volatile Compounds 75
B. Atmospheric Transport and Deposition Models 76
Mass Balance Models 77
Receptor Models 78
Air Quality Simulation Models 79
C. Comparing Models Used in Great Waters Studies 81
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TABLE OF CONTENTS
(continued)
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IV. MAJOR WATERBODIES OF THE GREAT WATERS: An Overview of Programs
and Efforts Addressing Atmospheric Deposition 85
A. The Great Lakes 89
Atmospheric Deposition of Great Lakes Contaminants 91
Program Actions to Characterize Atmospheric Contamination in the Great Lakes 100
Toxics Reduction Efforts in the Great Lakes 107
Addressing Data Gaps/Future Needs 116
B. Lake Champlain 119
Characterizing Toxic Contaminants in Lake Champlain 121
Addressing Toxic Contamination Reduction in Lake Champlain 126
C. Chesapeake Bay 129
Chesapeake Bay Program 129
Atmospheric Deposition of Nitrogen to Chesapeake Bay 132
Toxic Contaminant Deposition to the Chesapeake Bay 148
D. Coastal Waters 161
National Estuary Program 161
National Estuarine Research Reserve System 163
Gulf of Mexico Program 163
Studies of Atmospheric Deposition in NEP and Other Coastal Waters 165
Future Research Needs in NEP and Other Coastal Waters 172
V. CONCLUSIONS AND FUTURE DIRECTIONS 175
A. Reporting on the Role of Atmospheric Deposition to the Great Waters and
Specific Actions Proposed 177
Contribution of Atmospheric Deposition to Pollutant Loadings in the Great Waters ... 177
Contribution of Atmospheric Deposition to Adverse Human Health Effects or
Adverse Environmental Effects in the Great Waters 179
Emission Sources that Contribute to Atmospheric Deposition in the Great Waters .... 181
Contribution of Atmospheric Pollutant Loading to Exceedances of Water Quality
Standards and Drinking Water Standards or Exceedances of Objectives of the Great
Lakes Water Quality Agreement 183
Description of Revisions to Requirements, Standards, or Limitations Pursuant to the
Clean Air Act and Other Applicable Federal Laws, as Necessary 183
B. Future Directions 185
Determine Management/Regulatory Actions for Focus Pollutants 185
Continue Monitoring and Research Efforts to Support Management/Regulatory
Actions 186
Expand Modeling Efforts to Estimate Atmospheric Loadings to Great Waters 188
Increase Focus on Identification of Emissions Sources 188
Continue to Promote Pollution Reduction in the Great Waters 188
Assess Economic Impact of Pollution to the Great Waters 190
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TABLE OF CONTENTS
(continued)
PAGE
V. CONCLUSIONS AND FUTURE DIRECTIONS (continued)
C. Draft Determination of Whether CAA Section 112 Authorities are Adequate to Prevent Adverse
Effects to Public Health and the Environment from Deposition of HAPs 190
REFERENCES 193
APPENDICES
A. Status of Actions Recommended in First Report to Congress A-l
B. Fish Consumption Advisories B-l
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LIST OF TABLES
1-1 Pollutants of Concern in the Great Waters 9
1-2 Great Waters Pollutants of Concern and CAA Section 112 13
II-l Summary of Water Quality Criteria Used for Comparison in This Report 20
II-2 Comparison of Water Quality Criteria to Pollutant Concentrations in the
Great Lakes 21
II-3 Concentration of Total PCBs in Lake Superior Water Column 22
II-4 Commercial Fishing Bans in the Great Waters 24
II-5 Fish Consumption Advisories in the Great Lakes and Lake Champlain 25
II-6 Fish Consumption Advisories in Selected Coastal Waters 25
II-7 Eight-Year Trends of Pollutant Concentrations in Mussel Watch Project
(1986-1993) 31
II-8 Potential Effects of the Pollutants of Concern on Aquatic Life and Wildlife 45
II-9 Potential Human Health Effects Associated With Pollutants of Concern 59
11-10 Mean Serum PCB and DDT Levels in Fish Eaters and Controls
(1982 vs. 1989) 62
11-11 Lifetime Cancer Risks in Various Great Lakes Subpopulations Versus EPA's Appropriate Range of
Risk to Human Health 67
III-l Summary of Atmospheric Transport and Deposition Models Applied to the Great Waters 83
IV-1 Atmospheric Loading Estimates for Selected Pollutants in the Great Lakes 93
IV-2 Average Estimated Atmospheric Loadings of Selected Pollutants to the Great Lakes (1991-1993) . 94
IV-3 Specific Pollutant Reduction Goals Under the Great Lakes Binational Toxics
Strategy 112
IV-4 Summary of Some Major Programs to Address Atmospheric Contamination in the Great Lakes . 117
IV-5 Comparison of Mean Total Atmospheric Mercury Concentrations (Gaseous and Participate Phases
and in Precipitation) 124
IV-6 Comparison of Annual Mercury Deposition Estimates 125
IV-7 Chesapeake Bay Basin Nutrient Reduction and Loading Caps by Major Tributary Basin 133
IV-8 Nitrogen Retention Assumptions Used in Chesapeake Bay Loading Studies 141
IV-9 Annual Atmospheric Loadings of Trace Metals and Organic Contaminants to the Chesapeake Bay 157
IV-10 Relative Importance of Sources of Trace Metals and Organic Contaminants to Chesapeake Bay . 159
IV-11 Estimates of Atmospheric Nitrogen Loadings to Selected Coastal Waters 166
IV-12 Studies of Atmospheric Loadings of Toxic Pollutants to NEP Coastal Waters 167
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LIST OF FIGURES
1-1 Locations of the Great Waters 1
II-l Assessing Contamination in a Waterbody 28
II-2 Role of Ah Receptor in Biological Responses to Dioxin Exposure 49
III-l Atmospheric Deposition Processes 72
IV-1 Great Lakes Basin 90
IV-2 PCBs and DDT in Lake Trout from Lake Michigan 92
IV-3 Seasonal Atmospheric Loadings of PCBs in Lake Michigan (1994) 97
IV-4 Atmospheric Loadings of Lead to the Great Lakes (1988-1994) 99
IV-5 Atmospheric Monitoring Sites in the Great Lakes Region 102
IV-6 Lake Champlain Basin 120
IV-7 Atmospheric Mercury in Lake Champlain Basin 123
IV-8 Chesapeake Bay Watershed 130
IV-9 Major Tributary Basins of the Chesapeake Bay 134
IV-10 Chesapeake Bay Airshed 135
IV-11 NOX Emission Sources in the Major Bay Influencing States 136
IV-12 RADM Total (Wet and Dry) Nitrate Deposition from Utility Sources 137
IV-13 RADM Total (Wet and Dry) Nitrate Deposition from Mobile Sources 137
IV-14 Watershed and Estuary Model Integration 143
IV-15 Integrated Model Improvements 143
IV-16 Reductions in Anoxia Under Nutrient Reduction Scenarios 145
IV-17 Sampling Locations for Chesapeake Bay Toxic Contaminant Atmospheric
Deposition Studies 151
IV-18 Comparison of 13 PAHs and Total PCBs in Precipitation (1992) from
Chesapeake Bay and Great Lakes Sampling Sites 154
IV-19 Comparison of Chesapeake Bay and Great Lakes Atmospheric Depositional
Fluxes 156
IV-20 Locations of NEP and NERRS Sites 162
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LIST OF ABBREVIATIONS AND ACRONYMS
Ah
AOC
AQSM
ATSDR
AWQC
B(a)P
CAA
CBADS
CBOS
CBP
CCMP
CMB
CWA
ODD
DDE
DDT
DBS
dL
EMAP
EPA
FDA
g
GLWQA
GLWQB
GLWQC
GLWQG
GLWQO
GMP
HAP
HCB
ct-HCH, Y-HCH
Hg
IADN
kg
km, km2, km3
L
LaMP
LCBP
LMUATS
LQER
MACT
MCL
m2, m3
mg
NAAQS
NADP
NAPAP
NEP
NERRS
Aryl hydrocarbon
Area of Concern
Air quality simulation model
Agency for Toxic Substances and Disease Registry
Ambient water quality criterion or criteria
Benzo(a)pyrene
Clean Air Act
Chesapeake Bay Atmospheric Deposition Study
Chesapeake Bay Observing System
Chesapeake Bay Program
Comprehensive Conservation and Management Plan
Chemical mass balance
Clean Water Act
Dichlorodiphenyldichloroethane
Dichlorodiphenyldichloroethylene
Dichlorodiphenyltrichloroethane
Diethylstilbestrol
Deciliter
Environmental Monitoring and Assessment Program
U.S. Environmental Protection Agency
Food and Drug Administration
Gram
Great Lakes Water Quality Agreement
Great Lakes Water Quality Board
Great Lakes Water Quality Criteria
Great Lakes Water Quality Guidance
Great Lakes Water Quality Objective
Gulf of Mexico Program
Hazardous air pollutant
Hexachlorobenzene
alpha-Hexachlorocyclohexane, gamma-Hexachlorocyclohexane
Mercury
Integrated Atmospheric Deposition Network
International Joint Commission
Kilogram
Kilometer, square kilometer, cubic kilometer
liter
Lakewide Management Plan
Lake Champlain Basin Program
Lake Michigan urban air toxics study
Lesser-quantity emission rates
Maximum achievable control technology
Maximum contaminant level
Square meter, cubic meter
Microgram
Milligram
National ambient air quality standard
National Atmospheric Deposition Program
National Acid Precipitation Assessment Program
National Estuary Program
National Estuarine Research Reserve System
Nanogram
LIST OF ABBREVIATIONS AND ACRONYMS
(continued)
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NOAA National Oceanic and Atmospheric Administration
NOS Oxides of nitrogen
NS&T National Status and Trends
OAQPS Office of Air Quality Planning and Standards
OTC Ozone Transport Commission
PAH Polycyclic aromatic hydrocarbon
PCA Principal component analysis
PCB Polychlorinated biphenyl
pGLWQC Proposed Great Lakes water quality criteria
POM Polycyclic organic matter
ppb, ppm Parts per billion, parts per million
RADM Regional Acid Deposition Model
RAP Remedial Action Plan
RAPIDS Regional Air Pollutant Inventory Development System
RELMAP Regional Lagrangian Model of Air Pollution
REMSAD Regional Modeling System for Aerosols and Atmospheric Deposition
RPM Regional Particulate Model
SAB Science Advisory Board
SAV Submerged aquatic vegetation
SETAC Society of Environmental Toxicology and Chemistry
SOLEC State of the Lakes Ecosystem Conference
TBADS Tampa Bay Atmospheric Deposition Study
TCDD Tetrachlorodibenzo-p-dioxin
TCDF Tetrachlorodibenzofuran
TRIADS Texas Integrated Atmospheric Deposition Study
TSCA Toxic Substances Control Act
VOC Volatile organic compound
yr Year
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CHAPTER I
OVERVIEW OF THE GREAT WATERS PROGRAM
Section 112 of the Clean Air Act (CAA) provides the legislative basis for ha2ardous air
pollutant (HAP) programs directed by the U.S. Environmental Protection Agency (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." EPA coordinates activities to address the
requirements of section 112(m) under the Great Waters program.
This report fulfills the requirements in section 112(m)(5), which directs EPA, in cooperation
with National Oceanic and Atmospheric Administration (NOAA), to periodically submit a Report
to Congress on atmospheric deposition to the Great Waters. The report is to describe "results of
any monitoring, studies, and investigations conducted pursuant to" section 112(m). The First
Report to Congress on atmospheric deposition to the Great Waters, referred to throughout this
report as the "First Report to Congress," was published in May 1994 (U.S. EPA 1994a). This
document is the Second Report to Congress and is intended to be an update of the information
presented in the First Report to Congress.
The waterbodies collectively referred to as the "Great Waters" in this report are the Great
Lakes, Lake Champlain, Chesapeake Bay, and specific coastal waters (i.e., defined in the statute as
coastal waters designated through the National Estuary Program and the National Estuarine
Research Reserve System). (See Figure 1-1 for the locations of these waterbodies.)
FIGURE 1-1
Locations of the Great Waters
Chesapeake
Bay
Great Waters designated by name
EPA National Estuary Program (NEP) Site
NOAA NERRS Designated Site
NOAA NERRS Proposed Site
EPA NEP site and NOAA NERRS Designated Site
EPA NEP site and NOAA NERRS Proposed Site
NOAA—National Oceanic and Atmospheric
Administration
NERRS—National Estuarine Research Reserve System
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CHAPTER I
THE SECOND REPORT TO CONGRESS
I.A The Second Report to Congress
Goals of the Report
The main objective of this report is to update what is known about atmospheric deposition
of pollutants to the Great Waters based on the scientific data available since publication of the First
Report to Congress. The report focuses on research and activities in specific waterbodies to further
understand and promote reductions of overall contaminant loadings to the Great Waters. In
addition, this report includes a brief discussion of EPA's draft determination of the adequacy of
section 112 to protect the Great Waters from deposition of HAP emissions from domestic
stationary sources (see Chapter V).
EPA intends for this report to be an update of the First Report to Congress and has
attempted to minimi2e restating information. In some instances, important findings or issues raised
in the First Report to Congress are reiterated in this report to provide background information or to
highlight an issue that continues to be significant to the Great Waters. For more detailed
information on atmospheric deposition to the Great Waters, readers are encouraged to refer to the
First Report to Congress (U.S. EPA 1994a), which summari2ed the scientific understanding of
atmospheric deposition at that time and identified regulatory and research needs.
The scientific information presented in this report, together with the findings and
recommendations identified in the First Report to Congress, should be used together to assess the
progress since the First Report to Congress, and what data gaps still exist. Because of the short time
period since the First Report to Congress, projects that were initiated after the release of the report
or multi-year fieldwork projects, in most instances, are still in the data-gathering stage. Therefore,
the results of these efforts cannot yet be analyzed. However, the objectives and status of these
efforts are described in the report.
As in the First Report to Congress, the Second Report shows that data on effects, loadings,
and sources are available to a certain extent; however, information to assess the linkage between
these components remains inadequate, and therefore, unanswered questions, as well as uncertainties,
persist for some of these issues. This report proposes a number of future directions (see Chapter V)
to reduce uncertainty in several areas.
Report Preparation
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 sources that provide relevant information on Great Waters issues, but does not
attempt to be comprehensive in the references cited. In general, literature published by late fall 1996
is included. Data on human health and ecological effects of pollutants of concern are based on a
search for scientific literature published between completion of the background document on
exposure and effects from the First Report to Congress (Swain et al. 1992a) through 1995. In a few
instances throughout the report, more recent articles are included. In addition, in sections that are
new to this report, older articles may be cited. Interested parties who know of other studies that
may be pertinent to issues regarding atmospheric deposition to the Great Waters are encouraged to
submit a copy of the article or a complete citation of the reference to EPA. Every effort will be
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made by EPA to review the article and to determine whether the information is relevant for the
Third Report to Congress on atmospheric deposition to the Great Waters.
In addition to literature searches for current information on effects, current scientific
information about atmospheric deposition to the Great Waters was compiled from two symposia
held at the annual meeting of the Society of Environmental Toxicology and Chemistry (SETAC) in
Denver, Colorado, from October 31 through November 4, 1994. Invited researchers presented
findings from current research relevant to the Great Waters program. These findings have been
assembled in a book entitled Atmospheric Deposition of Contaminants to the Great Lakes and Coastal Waters
(Baker 1997).1 In addition, EPA incorporated findings from recent investigations that have been
funded by and/or conducted in connection with the Great Waters program, and has integrated
findings from other significant EPA projects such the reassessment of dioxin and dioxin-like
compounds (U.S. EPA 1994c, 1994d). Much of the waterbody-specific information presented in
this report was provided by the EPA offices that coordinate investigation, restoration, and
maintenance efforts in that waterbody (e.g., Great Lakes National Program Office, Chesapeake Bay
Program Office).
The available waterbody-specific information on deposition of air pollutants focuses in large
part on the Great Lakes and Chesapeake Bay. The Great Lakes have been a focus of the Great
Waters Reports to Congress because, with their importance as the largest freshwater system in the
United States and the observations reported for decades of toxic contamination in organisms living
in the Great Lakes, there exists the best base of information on which to build. In addition, studies
from the 1980s show atmospheric deposition to be a significant route of introducing pollutants to
the Lakes. Knowledge gained of the conditions of the Great Lakes is useful in evaluating
atmospheric deposition in other freshwaters as well. For example, researchers at Lake Champlain
have developed scientific programs to determine the role of atmospheric deposition, particularly
mercury, in water pollution. This report also focuses on Chesapeake Bay because accelerated
eutrophication and its effects on the Bay have been recogni2ed for over a decade. Accelerated
eutrophication in the Bay is attributed, in part, to nitrogen loadings deposited from the atmosphere
to the surrounding watershed, as well as directly into the Bay itself. Similar circumstances affect
other U.S. estuaries, and information collected and applied in Chesapeake Bay will be useful for
these waterbodies. For example, EPA has sponsored studies to refine the methodology used for
estimating sources of nitrogen in Chesapeake Bay and to apply the methodology to estuaries in
Galveston Bay, Texas, and Tampa Bay, Florida. A discussion of atmospheric deposition specific to
each of the Great Waters — Great Lakes, Lake Champlain, Chesapeake Bay, and other coastal
waters — is presented in Chapter IV.
The remaining sections of this chapter provide an overview of the findings from the First
Report to Congress, as well as recent research activities in the Great Waters, followed by discussion
of the air pollutants that are of particular concern to the Great Waters.
1 Baker (1997) was still in press as of June 30, 1997.
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I.B The First Report to Congress
The objective of the First Report to Congress was to describe what was known about
atmospheric deposition of toxic chemicals to the Great Waters and present any appropriate
regulatory recommendations based on the scientific information available at the time. The scientific
content of the First Report to Congress was based mainly on three background documents prepared
by committees of leading independent scientists (Baker et al. 1993; Keeler et al. 1993; Swain et al.
1992a). The information in these documents was used to answer three main scientific questions,
develop scientific and policy conclusions, and recommend next steps. The three scientific questions
were:
1. What human health and environmental effects are associated with the pollutants of
concern in the Great Waters?
2. What is the relative importance of atmospheric deposition in causing contamination
in the Great Waters?
3. What sources are significant contributors to atmospheric loadings to the Great
Waters?
From the data compiled, three general responses to these questions were developed:
4 Adverse effects (e.g., cancer, developmental effects) in humans and animals associated with
exposure to the Great Waters pollutants of concern are fairly well understood. However,
data are insufficient to establish a quantitative link between atmospheric deposition of these
pollutants and their related effects.
4 Atmospheric deposition can be a significant contributor of toxic chemicals to the Great
Waters. The relative importance of atmospheric loading for a particular chemical in a given
waterbody depends on characteristics of the waterbody, properties of the chemical, and the
kind and amount of airborne, waterborne, and other sources.
4 Many sources and source categories of pollutants of concern to the Great Waters have been
identified. However, identification of particular sources responsible for the deposited
pollutants in specific waterbodies is complicated since atmospheric loadings can originate
from local, regional, and global sources.
Specific conclusions from the First Report to Congress, based on scientific data available at
that time, included:
4 Persistence and the tendency to bioaccumulate, critical characteristics of the Great Waters
pollutants of concern, result in potentially greater human and ecological exposure to a
pollutant in the environment.
4 Exceedances of water quality criteria and standards have occurred for some of the pollutants
in some waterbodies.
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4 Adverse effects on human health and wildlife have been observed due to exposure, especially
through fish consumption, to persistent pollutants that bioaccumulate.
4 In addition to cancer, noncancer effects (e.g., nervous system damage, immunological
effects) caused by the pollutants can be a significant human health concern, and may affect
some individuals exposed to levels above certain thresholds. Developing embryos and
fetuses and breast-fed infants are given greater attention because they may be more
susceptible than the general population to the adverse effects of these chemicals.
4 Ecological effects on animal populations due to the pollutants of concern can be significant,
such as immune function impairment, reproductive problems, and neurological changes that
affect survival. Sometimes the effects on wildlife may be delayed and/or the symptoms
subtle so that the effects are easily overlooked.
4 Eutrophication resulting from excess nitrogen inputs is a major problem in some U.S.
estuarine and coastal waters, and the relative contribution from atmospheric deposition of
nitrogen to this problem can be significant. Ecological effects, ranging from nuisance algal
blooms to oxygen depletion and fish kills, and adverse economic impacts to the waterbody
region may result.
4 Case studies have shown that atmospheric deposition can be a major contributor of mercury,
nitrogen, polycyclic organic matter (POM), and polychlorinated biphenyls (PCBs) in
waterbodies. The available information generally includes relative loadings estimates.
Attention also should be given to the absolute quantity of the loadings because even small
amounts of pollutants that bioaccumulate may produce a significant burden in fish and,
ultimately, in humans and other fish-eating animals.
4 Airborne emissions from both local and distant sources contribute to atmospheric deposition
of pollutants to waterbodies. Deposition patterns can be influenced by characteristics of the
pollutants and the source, and by weather and transport patterns.
4 Continued research is needed, especially to help determine atmospheric contributions, to
identify sources, to evaluate effects from low exposure levels, and to target HAPs that may
pose the most significant risk to human health and aquatic resources.
Readers should refer to the First Report to Congress for discussion of the specific
conclusions.
Based on the scientific conclusions in the First Report to Congress, EPA's principal policy
conclusion was that reasonable actions are justified by the available scientific information, even
though there are significant uncertainties associated with this information. While additional research
is needed to reduce these uncertainties, reasonable actions to decrease atmospheric loadings need
not wait for results of such information. To carry out its policy conclusion, EPA identified several
recommendations for action, which were divided into three strategic themes:
1. EPA will continue ongoing efforts to implement section 112 and other sections of
the CAA, as amended in 1990, and use the results of the First Report to Congress in
the development of policy that will reduce emissions of the Great Waters pollutants
of concern.
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THE FIRST REPORT TO CONGRESS
2. EPA recogni2es the need for an integrated multimedia approach to the problem of
atmospheric deposition of pollutants to waterbodies and, therefore, will utili2e
authorities beyond the CAA to reduce the human and environmental exposure to
Great Waters pollutants of concern.
3. EPA will continue to support research activities and will develop and implement a
strategy describing necessary research and policy assessments to address the
mandates of section 112(m).
The specific action items based on these three strategic themes are described in detail in the
First Report to Congress. The current status of each of the recommended action items is presented
in Appendix A.
I.C Highlights of Progress Since the First Report to Congress
Much progress has been
made since the First Report to
Congress on research and other
activities related to atmospheric
deposition, especially activities that
support section 112(m) mandates
(see sidebar). The activities
described in this report include
those carried out by many national
and regional EPA offices, as well as
NOAA and a number of states
(i.e., the programs and research
were not all performed by the
Great Waters program in EPA's
Office of Air and Radiation). This
report does not, however, attempt
to be comprehensive in describing
all the activities of these offices. A
brief overview of some of the
activities undertaken is presented
below.
4 EPA has worked with the
Great Lakes States to
continue development of
regional emission
inventories for the Great
Lakes and a data storage
and retrieval system. Data
collection was recently
completed, and the data
base will be updated
EPA Activities Addressing
Section 112(m) Requirements
Section 112(m) directs EPA, in cooperation with NOAA, to
identify and assess the extent of atmospheric deposition of toxic
pollutants to the Great Waters. As part of the assessment, EPA
supports the following activities:
• Monitoring of atmospheric deposition, including the
establishment of monitoring networks in the Great Lakes,
Chesapeake Bay, Lake Champlain, and coastal waters;
• Investigation of sources and deposition rates of air pollutants;
• Research for developing and improving monitoring methods
and for determining the relative contribution of atmospheric
pollutants to total pollutants in the Great Waters;
• Evaluation of adverse human health and environmental
effects;
• Identification of exceedances of water quality and drinking
water standards;
• Sampling of fish and wildlife for pollutants of concern;
• Characterization of sources of pollutants of concern; and
• Determinations of whether section 112 authority is "adequate
to prevent serious adverse effects to public health and
serious or widespread environmental effects" associated with
atmospheric deposition of HAPs to the Great Waters, and of
whether further emissions standards or control measures to
prevent such effects are necessary and appropriate. Based
on these determinations, EPA is directed to take additional
measures, as necessary and appropriate, to prevent such
adverse effects to human health and the environment.
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CHAPTER I
THE FIRST REPORT TO CONGRESS
annually. Work will continue to characterise mobile source emissions and to improve the
accuracy of the emissions inventory. Determining, categorising, and estimating the
magnitude of pollutant sources will be a significant step toward reduction of atmospheric
loading of pollutants to the Great Lakes.
4 Quantitative data continue to be gathered on atmospheric deposition of pollutants including
PCBs, DDT, dieldrin, and lindane in each of the Great Lakes through the Integrated
Atmospheric Deposition Network (IADN) (a joint U.S./Canadian monitoring network).
Recent data have been incorporated into deposition estimates for 1994, thereby allowing
comparison of data to 1992 results.
4 Atmospheric mercury concentration and deposition have been monitored continuously in
the Lake Champlain region in the last few years, which will be important for determining
atmospheric deposition trends in the lake basin.
4 A large-scale airshed model for Chesapeake Bay has been developed to determine the general
geographical location and type of sources of nitrogen emissions, and the relative
contributions of different sources and patterns of nitrogen deposition to the Bay watershed
and directly to tidal surface waters. Models of the Chesapeake Bay airshed, watershed, and
tidal waters were extensively revised to link daily atmospheric deposition loading data to
models of water quality impacts in the tidal Bay and resultant influences on Bay underwater
grasses, bottom benthic communities, and overlying fish habitat.
4 The Chesapeake Bay Atmospheric Deposition Study (CBADS) network was established and
the resultant data have been used to quantify atmospheric loadings and depositional fluxes of
toxic contaminants to the Bay, as part of the development of a larger basinwide chemical
contaminant loading and release inventory.
4 Research stations have been established to measure atmospheric deposition of nitrogen and
other selected pollutants in Tampa Bay, Galveston Bay, and Pamlico Sound and adjacent
estuaries (e.g, Neuse River Estuary, Newport River Estuary); collected data will be used to
determine annual atmospheric loadings of these pollutants and the relative contribution of
remote and local sources to atmospheric deposition in the waterbodies.
Chapter IV of this Report to Congress provides more details on the activities highlighted
above.
I.D Pollutants of Concern
Great Waters Pollutants of Concern and Reasons for Inclusion
As did the First Report to Congress, this report focuses on selected pollutants of concern
(see sidebar on next page). These pollutants are potentially of concern for atmospheric deposition
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CHAPTER I
THE FIRST REPORT TO CONGRESS
to the Great Waters.2 The general types of sources and uses (and use restrictions) of these pollutants
are briefly summarised in Table 1-1.
The list of 15 Great Waters pollutants
of concern has not been expanded since the
First Report to Congress. Three pesticides,
atrazine, hexachlorobutadiene, and
methoxychlor, mentioned in the First Report,
continue to be considered by EPA as potential
future additions to the Great Waters list of
pollutants of concern. Atrazine warrants
continued attention as a potential pollutant of
concern because of its widespread occurrence
(e.g., commonly used in the Great Lakes
basin), its at-least moderate persistence, and its
potential to cause a variety of effects on biota.
For these reasons, atrazine is also one of the
chemicals of focus for the Lake Michigan Mass
Balance Study (discussed in Chapter IV). The
other two pesticides under consideration for
future addition, hexachlorobutadiene and
methoxychlor, are both on the CAA HAPs list
and have the potential to bioaccumulate in the
food web. Additional information suggests
that atrazine and methoxychlor are potential
endocrine disrupters, a group of chemicals that
mimic or otherwise interfere with hormones in the
effects.
Great Waters Pollutants of Concern
Cadmium and cadmium compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene (HCB)
a-Hexachlorocyclohexane (a-HCH)
Lindane (v-hexachlorocyclohexane; y-HCH)
Lead and lead compounds
Mercury and mercury compounds
Polychlorinated biphenyls (PCBs)
Polycyclic organic matter (POM)
Tetrachlorodibenzo-p-dioxin, 2,3,7,8-
(TCDD; dioxins)
Tetrachlorodibenzofuran, 2,3,7,8-
(TCDF; furans)
Toxaphene
Nitrogen compounds
Under Evaluation for Addition to Great Waters List
Atrazine
Hexachlorobutadiene
Methoxychlor
body, resulting in various adverse biological
The 15 pollutants of concern for the Great Waters were selected based on available data on
their effects and deposition. Reasons for selecting these pollutants include:
4 All the pollutants, except for nitrogen compounds, persist in the environment and/or have a
high potential to accumulate in living organisms. All the pollutants can cause adverse effects
in humans and the environment.
4 All 15 pollutants are known air pollutants and are known to be present in atmospheric
deposition (e.g., rainfall, dry deposition).
4 Data indicate that these pollutants are present in the waters and biota of the Great Waters
and that one route of pollutants to these waterbodies is atmospheric deposition.
2 The pollutants of concern are not considered to be inclusive of all chemicals that may, now or in the future, be an important
component of atmospheric deposition to the Great Waters. While nitrogen is not listed as a HAP under section 112(b) of the CAA,
this report examines the contribution of excess levels of nitrogen to eutrophication. Acidification or "acid rain" is not discussed
because it is addressed under a separate CAA program.
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CHAPTER I
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TABLE 1-1
Pollutants of Concern in the Great Waters3
Pollutant
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
a-Hexachlorocyclohexane
(a-HCH)
Lindane
(y-Hexachlorocyclohexane;
Y-HCH)
Lead and compounds
Mercury and compounds
Polychlorinated biphenyls (PCBs)
Polycyclic organic matter (POM)0
TCDD (dioxins)
TCDF (furans)
Toxaphene
Nitrogen compounds
Examples of Uses1'
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.
Insecticide used widely in the 1970s and 1980s. All U.S. uses except termite control cancelled in 1978;
use for termite control voluntarily suspended in 1988. Use of existing stocks permitted.
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.
Insecticide used widely after introduction in late 1940s. Used in U.S. for termite control from 1972 until
registration voluntarily suspended in 1987.
Fungicide used as seed protectant until 1985. By-product of chlorinated compound and pesticide
manufacturing. Also a by-product of combustion of chlorine-containing materials. Present as a
contaminant in some pesticides.
Component of technical-HCH, an insecticide for which use is restricted in U.S., but which is used widely
in other countries.
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; however, many uses are still registered, but are expected to be voluntarily cancelled
in the future.
Naturally occurring element commonly used in gasoline and paint additives, 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 1 971 . 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.
Naturally occurring element often used in thermometers, electrical equipment (such as batteries and
switching equipment), and industrial control instruments. Released from many combustion,
manufacturing, and natural processes. Banned as a paint additive in U.S. in both interior (1990) and
exterior (1 991 ) paint.
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 1 977 and uses were significantly restricted in 1 979. Still used for some purposes because of
stability and heat resistance, and still present in certain electrical equipment used throughout the United
States.
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.
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.
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.
Insecticide used widely on cotton in the southern U.S. until the late 1970s. Most U.S. uses banned in
1982; remaining uses cancelled in 1987.
By-products of power generation, industrial, and motor vehicle fossil fuel combustion processes (NO x
and NH3). Also, compounds used in fertilizers and released from agricultural animal manures (NHj).
a Source: Seethe First Report to Congress for references for this table (U.S. EPA 1994a).
b Applicable restrictions (including bans) on use or manufacture in United States also are described.
0 POM is a large class of chemicals consisting of organic compounds having multiple benzene rings and a boiling point greater than
100° C. Polycyclic aromatic hydrocarbons (PAHs) are a chemical class that is a subset of POM.
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These pollutants overlap substantially with the toxic air pollutants that ranked highest in an
EPA-sponsored study (ICF 1991) to identify priority chemicals having characteristics that
lead to potential adverse effects in the Great Waters.
With the exception of dieldrin and nitrogen compounds, all of these pollutants are listed as
HAPs under section 112(b) of the CAA.3
With the exception of 2,3,7,8-TCDF and nitrogen compounds, these pollutants are included
on the list of pollutants that were the initial focus of the EPA/state Great Lakes Water
Quality Initiative.4 They are considered to be potentially significant as air pollutants
deposited to the Great Lakes.
Ten of the 15 pollutants are designated as bioaccumulative chemicals of concern under
EPA's Great Lakes Water Quality Guidance.5
Six of the 15 pollutants (cadmium, chlordane, lead, mercury, PCBs, and several PAHs (which
are part of the POM class of compounds)) are on the Chesapeake Bay Toxics of Concern
list, and two more pollutants, dieldrin and toxaphene, are listed as potential future additions
to this list.
Nitrogen compounds play an important role in excessive nutrient enrichment in many
estuaries and coastal waters, and numerous studies indicate that atmospheric loadings of
nitrogen to the Chesapeake Bay and other coastal waters are a significant portion of total
nitrogen loadings. In most freshwaters, nitrogen compounds play a less immediate role in
promoting excessive enrichment. For example, airborne nitrogen compounds are not of
concern currently in the Great Lakes.
The pollutant list overlaps substantially with several sets of Great Lakes chemicals of concern
selected by other scientific and regulatory groups, including the Great Lakes Water Quality
Board (GLWQB) of the International Joint Commission (IJC), a cooperative committee
comprised of U.S. and Canadian representatives.
3 Several pollutants of concern are listed by a different name in section 112(b). The pollutants of concern are listed in section
112(b) as: cadmium compounds, chlordane, DDE, hexachlorobenzene, lindane (all isomers, which includes tt-HCH), lead
compounds, mercury compounds, PCBs, POM, 2,3,7,8-TCDD, dibenzofurans, and toxaphene. In addition, hexachlorobutadiene and
methoxychlor are listed in section 112(b).
4 Established in 1989 to a provide consistent level of environmental protection for the Great Lakes ecosystem, this Initiative
supported principles and goals of the 1986 Great Lakes Toxic Substances Control Agreement (Governors' Agreement).
The Final Water Quality Guidance for the Great Lakes System was released in 1995 (60 Federal Register 15366) and resulted in the
deletion of six chemicals (including aldrin, endrin, methoxychlor) from the proposed 1993 list of bioaccumulative chemicals of
concern. The final guidance also eliminated the list of 10 pollutants considered potential bioaccumulative chemicals of concern.
Although furans (2,3,7,8-TCDF) are not specified in the 1995 guidance, criteria for furans may eventually be set.
6 Atrazine is also found on the Chesapeake Bay Toxics of Concern List.
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Use of Pollutant Groups
In some sections of this report, discussion of the Great Waters pollutants of concern is
organi2ed by pollutant group. The five pollutant groups used in this report are described below.
Many of the pollutants may fit into more than one group, but have been placed in the most
appropriate category.
EPA has organi2ed the pollutants of concern in these five groups for several reasons. First,
the pollutants in each group generally originate from similar sources or are released through similar
mechanisms. Thus, action proposed to reduce emissions of individual pollutants may be applied
more broadly to the entire group. Second, pollutants in each group may have similar chemical
characteristics, allowing for generali2ations related to deposition and cycling within the environment.
Third, separating the pollutants into various groups allows for pollutants with unique regulatory
concerns, such as mercury and nitrogen, to be highlighted and emphasi2ed in the Report to
Congress. Finally, grouping the pollutants helps decision-makers develop conclusions about
pollutants with similar chemical/physical behavior or sources, where there are limited data.
4 Mercury and mercury compounds. Mercury is released as an air pollutant from a variety
of natural and anthropogenic area and point sources (including combustion and
manufacturing sources). Although mercury is a metal, it is treated in this report as a separate
pollutant group because it behaves differently in the environment than other metals and
produces different types of effects, as well as because of the comprehensive data that are
available for it. Mercury can be found in elemental, inorganic, or organic forms in the
environment. In aquatic species, mercury exists primarily as organic mercury (e.g.,
methylmercury), which can bioaccumulate in tissues and biomagnify in the food web. In
addition, special emphasis is given to mercury emissions in the CAA. Several subsections of
section 112 require studies to be conducted on mercury as a toxic air pollutant; a review draft
of an EPA report related to atmospheric emissions of mercury was submitted to the Science
Advisory Board (SAB) in 1996. When submitted to Congress, the final Mercury Study
Report will fulfill the mandate under CAA section 112(n)(l)(B) that the study consider:
• The rate and mass of mercury emissions;
• The health and environmental effects of such emissions;
• Technologies that are available to control such emissions; and
• The cost of these control technologies.
4 Other metals. Cadmium compounds and lead compounds comprise this group. These
metal compounds are released from various combustion and production processes. Note,
however, that a significant source of lead was reduced following the phaseout of lead in
gasoline additives that began in the early 1970s.
4 Combustion emissions. The pollutants in this group include PCBs, POM, 2,3,7,8-TCDD,
and 2,3,7,8-TCDF. (See the sidebar on the next page for a discussion of TCDD and TCDF.)
These pollutants generally are released during incomplete combustion of fossil fuels and/or
combustion during manufacturing or incineration processes. PCBs, though historically used
in electrical equipment and hydraulic fluids, are included in this group because they may be
released to the atmosphere in combustion gases when PCB-containing materials are burned.
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Pesticides. This group includes
chlordane, DDT/DDE, dieldrin,
hexachloroben2ene, a-HCH,
lindane, and toxaphene. Although
the use of these pesticides is
significantly limited in the United
States, they continue to be of
concern in the Great Waters
because of their persistence in the
environment and the long-range
transport from other countries in
which the pesticides are still used.
Atra2ine, hexachlorobutadiene, and
methoxychlor are potential future
additions to this group.
Dioxins and Furans
Section 112(b) of the CAA includes in its list of
HAPs "2,3,7,8-tetrachlorodibenzo-p-dioxin" and
"dibenzofuran." These two substances are part of a
much larger class of compounds, as discussed below.
Dibenzo-p-dioxin and dibenzofuran molecules
both carry single hydrogen atoms bonded to carbon
atoms at the outside corners. When chlorine atoms
are substituted for any (or all) of these hydrogens, the
compounds become chlorinated dibenzo-p-dioxins and
chlorinated dibenzofurans (CDDs and CDFs). The
presence of chlorine may increase the toxicity of the
compound by many orders of magnitude, depending
on their number and location. There are 75 possible
CDD compounds and 135 possible CDF compounds.
Each of these individual CDD and CDF forms is called
a "congener." It is these CDD and CDF congeners that
are commonly referred to as "dioxins" and "furans."
The terms "dioxins" or'TCDD" and "furans" or'TCDF"
are used in this report to refer to all CDD and CDF
congeners, respectively.
4 Nitrogen compounds. This
group includes nitrogen oxides,
reduced nitrogen compounds (such
as ammonia and ammonium), and
organic nitrogen. These pollutants
are released through both natural
and anthropogenic pathways.
Although nitrogen oxides are fossil fuel combustion by-products, nitrogen compounds are
treated as a separate pollutant group because: (1) other measures are being taken to control
nitrogen through programs related to ground-level O2one and acid precipitation; (2) nitrogen,
unlike the other selected pollutants of concern, is an essential nutrient and is not listed as a
HAP under CAA section 112(b); and (3) when present in excessive amounts, nitrogen (in
oxides and other compounds that are plant nutrients) is the nutrient driving the accelerated
eutrophication of most estuarine and coastal waters, resulting in significant adverse
ecosystem effects. Unlike the other pollutants, nitrogen is a required nutrient that supports
the ecosystem and becomes a pollutant when it reaches levels that result in overfertili2ation
with deterioration of water quality.
Relationship of Pollutants of Concern to Section 112 and Other
CAA Requirements
Table 1-2 presents the section 112 requirements that may regulate emissions of each pollutant
of concern. As shown, emissions of mercury are covered most comprehensively by section 112
requirements, followed by emissions of lead compounds, POM, TCDD, and TCDF. (Emissions of
lead compounds also are regulated under the CAA Tide I criteria air pollutant program.) Emissions of
hexachloroben2ene and PCBs may be regulated under the maximum achievable control technology
(MACT) standards required by sections 112(d), (g), and (j), and under 112(c)(6). Emissions of cadmium
compounds are covered under the MACT standards and, for electric utility steam generating units,
under 112(n)(l)(A). For several pesticides, the development of MACT standards is the main section
112 requirement that may control emissions of these pollutants, to the extent that major sources of air
emissions still exist in the United States. Section 112(f), which is not included in the table, is intended
to address the public health risks and adverse environmental effects from HAP
-12-
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TABLE 1-2
Great Waters Pollutants of Concern and CAA Section 112
Pollutant
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
a-HCH
Lead and compounds'1
Lindane
Mercury and compounds
PCBs
Polycyclic organic matter (POM)
TCDD (dioxins)
TCDF (furans)
Toxaphene
Nitrogen compounds0
Applicable CAA Section 112 Activities3
112(b)
•
•
•
•
•
•
•
•
•
•
•
•
•
112(c)(6)
•
•
•
•
•
•
•
H2(d),(g),(h),(j)
•
•
•
•
•
•
•
•
•
•
•
•
•
112(n)(1)(A)
•
•
•
•
•
•
112(n)(1)(B)
•
112(n)(1)(C)
•
a 112(b) = HAP list; the pollutants of concern are regulated under section 112 only by their name as listed in section 112(b) (cadmium compounds,
chlordane, DDE, hexachlorobenzene, lindane (all isomers, which includes a-HCH), lead compounds, mercury compounds, PCBs, POM, 2,3,7,8-
TCDD, dibenzofurans, and toxaphene).
112(c)(6) = Sources accounting for 90 percent of these emissions to be subject to regulation
112(d),(g),(h),(j) = Emissions of HAPs from major sources subject to regulation by MACT standards
112(n)(1)(A) = Emissions of these six HAPs from electric utility steam generating units to be evaluated for regulation
112(n)(1)(B) = Emissions of mercury from electric utilities, municipal waste combustors, and other sources to be studied
112(n)(1)(C) = Report required on "threshold" level for human health effects from mercury
Does not include section 112(f), which is intended to address the public health risks and adverse environmental effects from HAP emissions remaining
after implementation of 112(d) standards.
b Lead compounds also regulated under the criteria air pollutant program.
c Nitrogen oxides (NOX) regulated under several other CAA programs, such as those that control criteria air pollutants, mobile source emissions, and
acid rain.
-------
CHAPTER I
THE FIRST REPORT TO CONGRESS
emissions remaining after implementation of section 112(d) MACT standards; these standards could apply to
any HAP for which it is determined that "residual risk" remains. Emissions of dieldrin and nitrogen
compounds are not currently addressed by the section 112 requirements listed in Table 1-2. Emissions of
certain nitrogen compounds, however, are regulated under several CAA programs other than section 112,
including the Title I criteria air pollutant program, the Title II mobile sources program, and the Title IV acid
deposition program.
Other sections of the CAA may also regulate emissions of the pollutants of concern. For example,
under section 129 of the CAA, which applies to municipal waste combustors, EPA is to develop numerical
emission limitations for several pollutants, including the following Great Waters pollutants of concern:
cadmium, dioxins, furans, lead, mercury, and nitrogen compounds (nitrogen oxides).
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CHAPTER II
EXPOSURE AND EFFECTS
Section 112(m) of the CAA requires EPA to assess the environmental and human health
effects attributable to atmospheric deposition to the Great Waters and to assess whether
atmospheric pollutant loadings to the Great Waters cause or contribute to exceedances of
drinking water or water quality standards.
Adverse effects on environmental and human health and exceedances of drinking water
or water quality standards that result from the pollutants of concern are pieces of a larger puzzle
of what happens to the pollutants of concern after they are deposited to the Great Waters. After
being deposited to water, the pollutants can bind to particles, concentrate at the water surface,
dissolve in the water, and/or (if sufficiently volatile) escape as gases back into the air. Ecosystems
and humans may be exposed to these pollutants through various exposure routes (e.g., food
consumption). Exceedances of water quality criteria or standards are one means of assessing the
levels of the pollutants in water and biota to which ecosystems and humans may be exposed.
Following exposure to the pollutants of concern, ecosystems and humans may experience
adverse health effects.
At this time, it is not possible to distinguish between effects caused by airborne pollutants
and the same pollutants delivered by waterborne or other routes. In the absence of data to the
contrary, EPA takes the position that the contribution of airborne pollutants to adverse effects
corresponds to the relative air contribution by various routes to pollutant loads, including
releases of historic loadings from sediments.
This chapter is divided into five sections that discuss:
• Exposure routes and extent of contamination in the Great Waters (Section II.A);
• Level of contamination in biota of the Great Waters (Section II.B);
• Potential ecological effects that may result from exposure to the pollutants of
concern (Section II.C);
• Potential human health effects that may result from exposure to the pollutants of
concern (Section II.D); and
• Other potential effects, such as recreational fishing losses, attributable to the
pollutants of concern (Section II.E).
Sections II.A, II.C, and II.D update information that was presented in the First Report to
Congress (U.S. EPA 1994a). These sections begin with a brief summary of the information
presented in the First Report to Congress to provide a foundation for the subsequent discussion
of the recent information available for this report.
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
-16-
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
II.A Exposure Routes and Extent of Contamination
This section presents information on the exposure routes of concern for humans and
ecosystems and the extent of contamination in the Great Waters. The measures used in this
report to assess pollutant exposure and the extent of contamination are exceedances of water
quality criteria and the issuance of fishing restrictions and fish consumption advisories. Levels of
contamination in biota are discussed separately in Section II.B.
As noted earlier, the relationship between exposure and resulting adverse effects of toxic
pollutants and atmospheric deposition is not well understood. As described in the First Report,
some correlations and linkages have been established between specific pollutants of concern and
exposure and effects in the Great Waters. Many pollutants that are a concern due to atmospheric
deposition also have a long history of direct surface water discharges to the Great Waters. In
addition, current pollutant levels in waterbodies may include the contribution of pollutants that
enter through groundwater, that are recycled from sediments, or that are resuspended, following
earlier deposition, and redeposited at other locations. There currently is no evidence available to
suggest that the pollutants deposited from the air will have effects on biota any different from
the effects of these same pollutants carried in water or found in sediment.
Conclusions from the First Report to Congress
As mentioned above, information from the First Report to Congress is presented here to
provide a foundation for the subsequent discussion of the recent information available for the
Second Report. The research findings and studies presented in the First Report, as well as the
background document on exposure and effects (Swain et al. 1992a), led to the following
conclusions concerning exposure routes and extent of contamination in the Great Waters:
4 For water pollutants that are derived from atmospheric deposition, the major routes of
exposure are fairly well understood. The main exposure routes of concern for animals
are intake of food, intake of drinking water, and direct contact with water. Exposure
routes for plants include water uptake and direct contact. For humans and fish-eating
birds and mammals, intake of food (e.g., contaminated fish) is the main exposure
route of concern for pollutants that are persistent in the environment and that tend to
bioaccumulate.
4 The pollutants of concern generally are persistent in the environment and tend to
accumulate in fat or muscle tissue and, as a result of food web interactions, reach the
highest concentrations in animals at the top of the food web, including humans.
These characteristics allow the pollutants to remain in the environment and animal
tissue for long periods of time, increasing the opportunity for exposure and resulting
in greater exposures to animals at the top of the food web.
4 The tendency of the pollutants of concern to bioconcentrate and biomagnify was
supported by numerous studies summarized in the First Report. (See sidebar on next
page for definition of terms. Note that these terms may be used with somewhat
different emphasis by different authors. This summary is based on common usages
from many articles reviewed for this report.) Evidence presented by these studies
included: (1) documented cases of elevated levels of persistent toxic pollutants in
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
various fish species compared to levels in
water and, in many cases, levels in sediment;
(2) data showing that predators (e.g., the
herring gull, bald eagle, and turtle) in the
Great Lakes region have had some of the
highest reported concentrations of persistent
toxic chemicals in their tissues; and (3) data
indicating that people who regularly
consumed fish from Lake Michigan in the
1970s had significantly higher concentrations
of PCBs and pesticides, such as DDT, in their
tissues compared with those who did not
consume fish.
Distinguishing Common Terms
Describing Bioaccumulation
Bioaccumulation is the uptake and retention
of a chemical by a living organism as a result of
intake of food, intake of drinking water, direct
contact, or inhalation.
Bioconcentration is the phenomenon by
which chemicals become more concentrated in an
organism than in its surrounding environment.
Biomagnification is the phenomenon by
which chemicals become more concentrated in
animals at higher levels in the food web.
Based on the most current
information available for the First
Report to Congress, portions of all of the Great Lakes and many associated waterbodies,
Chesapeake Bay, and Lake Champlain had some kind of advisory on fish consumption at
that time.
Understanding of the contribution of atmospheric deposition to overall exposure was
limited for the First Report to Congress because: (1) overall exposure to toxic water
pollutants had not been adequately quantified; (2) sufficient and accurate information on
all pollutant inputs and outputs was not available at that time; and (3) the difficulty in
distinguishing the origin of a pollutant (e.g., originated from the air) after it is in the
water made it difficult to link exposure, and resultant effects, to particular pathways (e.g.,
atmospheric deposition).
Although the exposure routes of concern have been identified, the concentrations of
pollutants in water to which humans, animals, and plants are exposed (i.e., the extent of
contamination) were not easily determined given available data at that time.
Few violations of existing drinking water standards (i.e., maximum contaminant levels or
MCLs) for the pollutants of concern were found in Great Lakes drinking water systems;
for the pollutants that exceeded their MCLs, much of the problem was thought to be
caused by the distribution system rather than the water source.
When maximum open water concentrations from Great Lakes sampling data taken
between 1980-1986 were compared to water quality criteria, six pollutants of concern
(cadmium, dieldrin, DDT/DDE, hexachlorobenzene, mercury, and PCBs) potentially
exceeded at least one criterion in at least one of the Great Lakes (see Appendix B of the
First Report to Congress). Maximum concentrations of most of the remaining Great
Waters pollutants in most of the lakes approached levels of concern. An updated
comparison of sampling data to water quality criteria is presented later in this section.
In Lake Champlain, limited sampling data indicated that lead was the only pollutant
of concern that exceeded applicable water quality criteria. In Chesapeake Bay, a
limited number of measured concentrations of cadmium and lead in the tidal
-18-
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
tributaries to the Chesapeake Bay exceeded EPA water quality criteria and state water
quality standards prior to 1993.
The remainder of this section presents updated information on exposure routes and
extent of contamination.
Current Understanding of Exposure Routes and Extent of Contamination
As indicated above and in the First Report to Congress, the exposure routes of concern for
humans and ecosystems are fairly well understood. Exposures can occur through intake of
drinking water, direct contact with water, and, especially important for humans and fish-eating
birds and mammals, intake of food. This section presents updated information on measures for
assessing the extent of contamination in the Great Waters.
COMPARISON TO WATER QUALITY CRITERIA
One means of assessing the extent of contamination in the Great Waters caused by the
pollutants of concern is to compare available water sampling data to drinking water standards
and other water quality criteria. Such comparisons are consistent with the requirement in
section 112(m) of the 1990 CAA Amendments for EPA to assess the contribution of atmospheric
deposition to exceedances of drinking water standards and other water quality standards and
criteria.
For national drinking water standards, few exceedances are known for the Great Waters
pollutants of concern based on current information in the Great Lakes. Since the First Report to
Congress, there continue to be few violations of existing maximum contaminant levels (MCLs) in
Great Lakes drinking water systems. Interpretation of this information is limited because the
exceedance of the MCL for a pollutant may be a result of a problem in the distribution system,
rather than the water source.
For other water quality criteria and standards, three sets of relevant water quality criteria
are compared with available Great Waters sampling data: EPA's national ambient water quality
criteria (AWQC); the U.S.-Canadian Great Lakes water quality objectives (GLWQOs); and Great
Lakes water quality criteria (GLWQC) developed by EPA and Great Lakes states. The first two
sets of criteria are the same as those used in the First Report, while the third set, GLWQC, was
released in 1995. Proposed GLWQC (pGLWQC) were used in the First Report, but these criteria
have since been finalized (U.S. EPA 1995a); see Chapter IV for more discussion on the
development of GLWQC. The three sets of criteria are briefly defined in Table II-l.
Water sampling data are compared with water quality criteria, rather than comparing
sediment contamination data or biological contamination data to appropriate standards, for
two main reasons: (1) the specific requirement in section 112(m) to report exceedances of
water quality standards and benchmarks, and (2) the limited availability of federal or other
widely accepted numerical benchmarks for sediments or living organisms for the selected
pollutants of concern. Because many of the pollutants of concern bioconcentrate and
biomagnify, water concentrations may understate the full potential for fish and wildlife to
contain high concentration levels; only the GLWQC account for the potential for
biomagnification. Therefore, the absence of water quality criteria exceedances for pollutants
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
that have a strong tendency to bind to sediments and to bioaccumulate does not necessarily
indicate the absence of contamination levels of potential human health or ecological concern.
Contamination levels in biota and sediments in the Great Waters are discussed in Section II.B.
Table II-2 compares recent estimates of total water column concentrations in the Great
Lakes for seven pollutants of concern for which sampling data exist (i.e., DDT/DDE, dieldrin,
hexachlorobenzene (HCB), cc-HCH, lindane, PCBs, and POM). The data are taken from studies
conducted between 1986 and 1991 by EPA, researchers funded by EPA, and Environment
Canada. Sampling data for the other pollutants of concern and for other Great Waters were not
readily available.
TABLE 11-1
Summary of Water Quality Criteria Used for Comparison in This Report
Criteria Set3
Summary
Ambient water quality
criteria (AWQC)
Designed to protect humans, and freshwater and saltwater animals and
plants from harmful effects resulting from chronic and acute exposures.
Reflect current knowledge on health and welfare effects, dispersal of
pollutants across media, and effects on animal and plant reproduction and
communities. Derived entirely with risk-based data (not cost or technology
considerations). National criteria provided by EPA as guidelines to states
for developing regulations.
Great Lakes water
quality objectives
(GLWQOs)
Developed through joint U.S.-Canadian agreement. Set for certain
chemicals to protect the most sensitive user of the water among humans,
aquatic life, and wildlife. For chemicals with no specific GLWQO,
concentrations in water (does not specify whether ambient water) and in
aquatic organisms should be lower than detection levels.
Great Lakes water
quality criteria
(GLWQC)
Developed by EPA and Great Lakes States. Specific to the Great Lakes
system. Form basis for new state water quality standards for ambient
waters of the Great Lakes system. Provided as guidelines to protect
aquatic life (for both acute and chronic exposure), wildlife (for exposure
through food webs), and humans (for chronic exposure through
consumption of both fish and drinking water and through water-related
recreation). Includes consideration of biomagnification.
a Sources: U.S. EPA 1986, IJC 1978, and U.S. EPA 1995a, respectively.
As shown in Table 11-2, total water column concentrations of dieldrin and PCBs exceed
their GLWQC at some locations in all of the Great Lakes, where data are available. Note that
DDT/DDE may also exceed its GLWQC (sampling data of < 0.00006 jug/L versus GLWQC of
0.000011 yUg/L), and that the criterion for POM is for polycyclic aromatic hydrocarbons (PAHs), a
subset of POM, while sampling data were available only for one POM compound (i.e.,
benzo(a)pyrene, or B(a)P). In addition, the concentrations of PCBs at some locations in Lakes
Erie, Huron, and Ontario are above the AWQC for human health. For the pollutants with
sampling data reported in both the First Report to Congress and this report (i.e., dieldrin,
DDT/DDE, HCB, and PCBs), the total water column concentrations presented in Table II-2 are
generally lower than the concentrations reported in the First Report to Congress and the levels
for DDT/DDE and HCB no longer exceed any of the water quality criteria.
-20-
-------
TABLE 11-2
Comparison of Water Quality Criteria to Pollutant Concentrations in the Great Lakes (ug/L)
Pollutant
DDT/DDEf
Dieldrin
HCB
a-HCH
Lindane
Total PCBs
POMh
National
AWQC: Fresh
Water
Aquatic Life'1
0.001
0.0019
—
—
0.08
0.014
—
National
AWQC:
Human
Health"
0.00024
0.00071
0.0072
0.092
0.186
0.00079
0.028
Great Lakes
Water Quality
Agreement
Objective0
0.003
0.0019
—
—
0.01
—
—
Great Lakes
Water
Quality
Criterion11
0.000011
0.0000065
0.00045
—
0.47
0.0000039
—
Total Water Column Concentration6
Lake
Superior
<0.00006
0.00026
<0.00004
0.0011
0.0004
0.00018
<0.00046
Lake
Michigan
NA
NA
NA
0.0016
0.00034
0.00020-
0.00036
NA
Lake
Huron
Lake
Erie
Lake
Ontario
<0.00006 | <0.00006 | <0.00006
0.00032- 1 0.00038 1 0.00028-
0.00035 | | 0.00032
0.000072
0.0015
0.00038
0.0007-
0.0009
<0.00046
0.000047
0.0011
0.00049
0.00122
<0.00046
0.000036
0.0008-
0.0009
0.00036
0.0012
<0. 00046
NA=No data available.
Highlighted boxes indicate exceedances of GLWQC; shaded boxes indicate exceedances of AWQC for human health.
a Values are for freshwater chronic criteria (U.S. EPA 1986).
b Values are for human chronic exposure through both fish consumption and drinking water (U.S. EPA 1986).
c Values are for protection of the most sensitive user of the water among humans, aquatic life and wildlife (IJC 1978).
d Values are the most stringent (i.e., lowest) among those for protection of human health, aquatic life, or wildlife (U.S. EPA 1995a).
e Concentrations are taken from De Vault et al. (1995) and L'ltalien (1993). Concentrations of dieldrin and PCBs that are reported as ranges represent two
different concentrations reported in two different studies. For a-HCH, the range of concentrations in Lake Ontario represents the range reported in a single
study.
f Sampling data are for p,p'-DDE.
9 Value for aldrin and dieldrin combined.
h AWQC for human health is for polycyclic aromatic hydrocarbons (PAHs), a subset of POM; sampling data are for benzo(a)pyrene, a PAH.
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
Meaningful trend data on pollutant concentrations in the Great Lakes are limited mainly
because the technology required to measure pollutants at the trace concentrations found in the
water column of the Great Lakes has become widely available only in the last few years (De
Vault et al. 1995). One recent study, however, has provided insight into water column trends for
PCBs in Lake Superior (Jeremiason et al. 1994). As shown in Table II-3, total PCB concentrations
in the Lake Superior water column show an overall decline from 1978 to 1992, though there is
some variation from year to year. In addition, based on the concentrations of the same 25 PCB
congeners measured in surface water samples collected between 1980 and 1992 by the same
laboratory (also shown in Table II-3), the concentrations of these PCB congeners has decreased at
a rate of approximately -0.00020 yUg/L per year. (For details on the collection methods and labora-
tory techniques used in this study, refer to Jeremiason et al. (1994).) The researchers believe that,
due to the remote location of Lake Superior and the absence of significant point source loadings,
the decline in PCB concentrations represents a continental decrease in atmospheric loading of
PCBs. (Other research suggests that cycling of PCBs in the environment, including volatilization
of gaseous PCBs from waterbodies, is an important consideration (see Chapter IV).) According to
the data, the concentrations of PCBs in Lake Superior were above the AWQC for human health
until approximately 1983 and still remain above the GLWQC (criteria shown in Table II-2).
TABLE 11-3
Concentration of Total PCBs in Lake Superior Water Column
Year
1978
1979
1980
1983
1986
1988
1990
1992
Total PCB
Concentration (ug/L)
0.001 73 ±0.00065
0.00404 ± 0.00056
0.001 13 ±0.00011
0.0008 ±0.00007
0.00056 ±0.00016
0.00033 ± 0.00004
0.00032 ± 0.00003
0.0001 8 ±0.00002
Total Concentration of 25
PCB Congeners (ug/L)
NA
NA
0.00099 ±0.00010
0.00073 ± 0.00006
0.00055 ±0.0001 5
0.00020 ± 0.00001
0.00021 ± 0.00001
0.00009 ± 0.00001
NA = Not applicable
Source: Jeremiason et al. 1994.
FISHING RESTRICTIONS AND FISH CONSUMPTION ADVISORIES
Another measure of contamination of the Great Waters caused by selected pollutants
of concern is the existence of fishing restrictions or fish consumption advisories. These
advisories are established as a means of limiting human exposure when fish taken from a
particular body of water are found to contain levels of pollutants that exceed recommended
intake levels (see sidebar on next page). Such advisories have immediate significance to the
general public by providing concrete examples of health concerns and affecting the public
use of waters and aquatic resources. States issue several different types of advisories for
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
waterbodies in an effort to reduce health risks
associated with exposure to pollutants in
certain freshwater fish and shellfish species:
• Informational health advisories:
advisories that fish tissue
contains contaminants but not
at levels high enough to
warrant advising people to
limit consumption.
• Advisories to limit fish
consumption: advisories to
either the general population
or subopulations potentially at
greater risk (e.g., pregnant or
nursing women, those who
fish for subsistence reasons) to
restrict the size and frequency
of meals of fish and shellfish;
• Advisories against fish consump-
tion: advisories to either the
general population or subpop-
ulations potentially at greater
risk (e.g., pregnant or nursing women) against consuming fish and shellfish;
• No-kill zones: notification that it is illegal to take, kill, or possess any fish from the
specified waters; and
• Commercial fishing bans: bans on the commercial harvest and sale of fish and
shellfish from the specified waterbody.
State advisory data are collected by EPA in a national data base. For each advisory, the
data base contains information such as waterbody name, pollutant name, fish species, population
targeted by advisory (called advisory type in this report), advisory status (e.g., active), and a
contact name and telephone number. The data base does not, however, contain information on
the levels of pollutants in fish or the benchmark levels set by a particular state for each advisory
type. The information in the data base available for use in this report was current through 1995
(U.S. EPA 1996b). For this report, EPA reviewed the data base for any of the above advisories
related to the Great Waters pollutants of concern in the Great Lakes, Lake Champlain,
Chesapeake Bay, and several coastal waters.7
According to the fish advisory data base, no informational health advisories were in
effect in any of the Great Waters. A portion of the Hudson River, which empties into the
New York/New Jersey Harbor, had an active no-kill zone for all fish related to PCBs. Table II-4
Interpreting Fish Advisory Data
Individual states are responsible for issuing
fish advisories. Generally, an advisory is issued
for a particular waterbody (or portion of
waterbody), pollutant, fish species, and advisory
type. In many advisories, the size of the fish
affects the type of advisory issued (e.g., for
walleye < 22", restricting meals in the general
population may be advised, while for walleye > 22"
not consuming the fish may be advised). For
several reasons, comparing advisories
quantitatively (e.g., counting the number of
advisories per waterbody) is difficult and therefore,
this Report does not do so. For example, a
waterbody may appear to have more fish
advisories than another waterbody, but it may be
that: (1) more states are involved (e.g., advisories
in Lake Ontario are issued only by New York, while
four states issue advisories for Lake Michigan; (2)
states have different methods or use different
standards for identifying fish species affected by
advisories, some of which may be more
comprehensive than others; or (3) a state may
issue an advisory for "all fish" making it difficult to
count this advisory with advisories for particular
fish species.
7 A more detailed description of the criteria EPA used to obtain information related to the Great Waters from the
fish advisory data base is provided in Appendix B.
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
lists the commercial fishing bans that were in effect in the Great Waters. As the table shows, the
commercial fishing bans in the Great Waters are all due to PCBs or dioxins.
TABLE 11-4
Commercial Fishing Bans in the Great Waters
Waterbody
(State Issuing Advisory)
Lake Champlain (NY)
Lake Ontario (NY)
Long Island Sound (NY)
New York/New Jersey Harbor
(various waters; NJ, NY)
Great Waters
Pollutant of Concern
PCBs
Dioxins, PCBs
PCBs
PCBs
Dioxins
Fish Species
Yellow perch
Eel
Striped bass
American eel, blue crab
striped bass
Blue crab, crustaceans,
striped bass
carp, goldfish,
fish, shellfish,
Source: U.S. EPA1996b.
There are many active advisories to limit or avoid fish consumption in the Great Waters.
Table II-5 (the Great Lakes and Lake Champlain) and Table 11-6 (selected coastal waters,
including Chesapeake Bay) indicate the type of advisories in effect for the Great Waters
pollutants of concern, in increasing order of severity of the advisory (i.e., from advisories to at-
risk subpopulations to restrict fish consumption up to advisories to the general population to not
eat certain fish). For the Great Lakes and Lake Champlain, only lake wide advisories are included
in Table II-5. Advisories for particular "hot spots" in these lakes (e.g., Green Bay), as well as the
lakewide advisories, are presented in Appendix B. In Table 11-6, the advisories for coastal waters
represent the advisories as they are identified in the data base. Therefore, advisories for some
coastal waters represent the entire waterbody (e.g., Tampa Bay), while others represent smaller
estuaries or portions of the waterbody (e.g., Baltimore Harbor). Appendix B provides details on
the waterbodies that represent the coastal water advisories. The fish consumption advisories
shown in the tables have been issued for at least one fish species and, in many cases, have been
issued for several fish species. For more detail on the fish species affected by the advisories and
the states that issued the advisories, refer to Appendix B.
As shown in Table II-5, fish consumption advisories in the lakes of the Great Waters are
most commonly associated with PCBs, followed by mercury, dioxins, and chlordane. For one
lake, Lake Superior, an advisory related to toxaphene also has been issued. In the selected
coastal waters, as shown in Table II-6, fish consumption advisories are most commonly
associated with PCBs, followed by dioxins. Several advisories related to mercury, chlordane, and
DDT also have been issued. Current fish advisories generally are associated with the same
pollutants of concern as in the First Report. Furthermore, in this report, fish advisory data are
available in more detail than were reported in the First Report (e.g., advisories by each state),
especially because of the recent availability of the fish advisory data base. In addition, some
states may have become more aggressive in their fish advisory programs. Therefore, the increase
in number of advisories presented in Appendix B does not necessarily reflect a higher level of
contamination in the Great Waters.
-24-
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TABLE 11-5
Fish Consumption Advisories in the Great Lakes and Lake Champlain
Pollutants
of Concern
Chlordane
Dioxins
Mercury
PCBs
Tnyaphfinfi
Great Lakes
Lake
Superior
•
o • n •
• n •
•
Lake
Michigan
• n •
o •
• n •
Lake Huron
• n •
• n •
• n •
Lake Erie
•
• •
Lake Ontario
• n •
• n •
Connecting
Channels
• n •
o • •
• n •
Lake
Champlain
• D
• D
TABLE 11-6
Fish Consumption Advisories in Selected Coastal Waters
Pollutants
of Concern
Chlordane
Dioxins
DDT
Mercury
PCRs
Chesapeake
Bay
•
•
Other Coastal Waters
Long Island
Sound
•
• n •
New York/New
Jersey Harbor
o • n •
• n •
Delaware Bay
•
0 • •
Tampa Bay
•
•
Galveston
Bay
• n
San Francisco
Bay
o • n •
o • n •
o • n •
o • n •
KEY: O Advisories to subpopulations potentially at greater risk (e.g., pregnant women) to restrict the size and frequency of meals offish and shellfish
• Advisories to the general population to restrict the size and frequency of meals of fish and shellfish
D Advisories to subpopulations potentially at greater risk (e.g., pregnant or nursing women) against consuming fish and shellfish
• Advisories to the general population against consuming fish and shellfish
Source: U.S. EPA1996b.
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CHAPTER II
EXPOSURE AND EXTENT OF CONTAMINATION
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CHAPTER II
CONTAMINATION OF BIOTA
II.B Contamination of Biota
Measurements of pollutant levels in biota provide information about the extent of
contamination in the waterbody, as well as potential bioaccumulation in the food web. Section
112(m)(l)(E) of the CAA requires EPA to sample biota, including fish and wildlife, in the Great
Waters for hazardous air pollutants and to identify the sources of these pollutants. Because
studies are already being performed under national programs such as the National Status and
Trends Program, Great Lakes National Program Office, Chesapeake Bay Program, as well as state
programs, EPA relies largely on these studies to support implementation of this CAA
requirement. These programs provide information on the extent of contamination in the
waterbodies, as reflected in tissues of living organisms. Contamination of biota also suggests
potential contribution from various exposure routes such as air and water, as well as
bioaccumulation in the food web. This section presents a brief overview of biota sampling
approaches and how the sampling data provide useful information for assessing the extent of
pollutant contamination in a waterbody. This overview includes a summary of two large-scale
studies that are designed to assess national pollutant levels in aquatic biota, and how the results
from these studies can apply to the Great Waters. This discussion is followed by a summary of
research efforts addressing biota contamination specific to the Great Waters.
Sampling Biota for Contamination
Different sampling approaches are
used to determine pollutant levels in biota
because each monitoring study has its own
objectives, such as to identify "hot spots" or
characterize a waterbody's general condition.
Therefore, caution must be taken in the
interpretation of data, as well as statistical
analyses applied to these data. To estimate
spatial or temporal patterns of
contamination, sophisticated sampling
designs are often used. Figure II-l illustrates
the importance of sampling various
components of an aquatic ecosystem when
attempting to characterize the condition of
the system.
In assessing contamination in a
waterbody, aquatic and terrestrial species
are often collected and analyzed. Game
fish are useful bioindicators because they
have long life spans, dominate the upper
end of the aquatic food web, and can
bioaccumulate many of the persistent
pollutants (see sidebar). Their population ^^^^^^^^^^^^^^^^^^^^^^^^^^^
levels may be affected by continued
exposure to environmental stresses, such as eutrophication and pollutant contamination, and
people become aware of changes in abundance of game fish. Reduced dissolved oxygen
concentrations in the water may affect growth, survival, or structural development of fish,
An Example of Bioaccumulation
in the Food Web
Of the pathways by which ecosystems and
components of ecosystems may be exposed to
atmospheric mercury, exposure of high trophic
level predatory wildlife to mercury in food is
particularly important. Mercury biomagnifies in
aquatic food chains, with the result that mercury
concentrations in tissue increase as trophic levels
increase. Therefore, the trophic level and feeding
habits of an animal influence the degree to which
that species is exposed to mercury. Predatory
animals primarily associated with aquatic food
chains accumulate more mercury than those
associated with terrestrial food chains. Thus, fish
eaters and their predators generally have the
highest exposure to mercury. Species with high
tissue levels of mercury include otter and mink,
which are top mammalian predators of aquatic
food chains. Top avian predators of aquatic-
based food chains include raptors such as the
osprey and bald eagle.
Sources: Bloom 1992; Eisler 1987a; Roelke et al.
1997; Wobeserand Swift 1976; Wren 1985.
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CHAPTER II
CONTAMINATION OF BIOTA
FIGURE 11-1
Assessing Contamination in a Waterbody
Fish-eating birds and mammals
are especially at risk from
pollutants that biomagnify.
Terrestrial Wildlife
Gamefish dominate the
upper end of the aquatic
food web and bioaccumulate
persistent pollutants.
Gsmefish
Forage Fish
Macrolnvertebrates
Fhytoplankton/
boplankton
Sediment.
Contaminants in sediments
can be reintroduced into the
food web through uptake by
benthic organisms.
Many pollutants settle to the
bottom and bind to sediments;
pollutant levels may be higher
than in surrounding water and
can be reintroduced through
resuspension by currents and
waves.
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CHAPTER II
CONTAMINATION OF BIOTA
while pollutant contamination may result in
decreased growth, reproduction, or survival of
fish (see Section II.C for information on
ecological effects). Contamination in fish can
enter the diet of humans and other animals
(see sidebar). Therefore, terrestrial wildlife,
such as fish-eating birds or mammals, are often
monitored. While all animals in the aquatic
environment have the potential to be affected
by pollutants, fish-eating birds and mammals
are especially at risk from pollutants that
biomagnify because they are frequently
exposed to high levels of these pollutants.
Contaminated sediments pose a
potential hazard to human health due to
biomagnification up the food web. Many
pollutants in the water settle to the bottom and
bind to sediments or remain in solution in the
water between the sediment particles.
Although some pollutants can be degraded by
bacteria, many persist in sediments for years,
even after the original source of contamination
has been removed (Howdeshell and Kites
1996). Therefore, pollutant levels in the
sediment may be higher than the
concentrations in the surrounding water
and/or biota, and should be interpreted
cautiously when extrapolating to potential
levels in biota. Pollutants in the contaminated
sediment can also be reintroduced into the
water column and can enter the food web
through benthic (bottom-dwelling) organisms
(e.g., clams, crustaceans, and worms), which
are prey to larger fish. Benthic community
structure, as well as pollutants in tissues of
benthic organisms, may serve as useful indicators
EPA Guidance For Issuing
Fish and Wildlife Consumption Advisories
In response to a 1990 request from the states,
EPA established The Fish and Wildlife
Contamination Program to assist states and tribes
assess and reduce health risks associated with
exposure to chemical contaminants in
noncommercially harvested (e.g., subsistence) fish
and wildlife. In partnership with states and tribes,
EPA has developed a series of guidance
documents which provide a scientifically sound,
cost-effective method for developing, issuing,
managing, and communicating fish consumption
advisories. Though many states use the EPA
guidance for developing fish and wildlife
consumption advisories, some states use parts of
the guidance selectively. A few states still apply
outdates methods for characterizing contaminants.
EPA continues to work with the states and tribes to
establish a national consistency in the methods
used for characterizing the risks posed by
contaminants in noncommercial fish and wildlife.
The Fish and Wildlife Contamination Program
has also worked with the states and tribes in
organizing training workshops and national
conferences. In addition, EPA manages national
data bases such as the Listing of Fish and Wildlife
Consumption Advisories (discussed in Section
II.A). The listing, which is updated annually,
includes an inventory of all fish and wildlife
consumption advisories issued by the states and
tribes. Because of additional sampling due to the
increased attention given to fish contamination, the
number of advisories issued by the states and
tribes has increased 72 percent, from 1,278
advisories in 1993 to 2,193 advisories issued in
1996. Most of these advisories have been issued
due to mercury contamination.
of sediment contamination.
Wide-scale monitoring studies have been conducted on pollutant contamination of biota
to assess large-scale regional and national impacts in U.S. waters. These programs provide
valuable information about major pollutants (e.g., where they are found and where they
bioaccumulate) and the extent of contamination in the waterbodies, although the source of
contamination (or contribution of atmospheric deposition) is generally not evaluated.
Two large-scale programs that assess the contamination of biota in major U.S.
waterbodies or coastal areas are the NOAA National Status and Trends (NS&T) Program and
the EPA Environmental Monitoring and Assessment Program (EMAP). The NS&T Program
monitors trends of more than 70 chemical contaminants (organic compounds and trace
-29-
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CHAPTER II
CONTAMINATION OF BIOTA
metals) in bottom-feeding fish, shellfish, and sediments at almost 300 coastal and estuarine
locations throughout the United States. A well-known project of the NS&T is the Mussel Watch.
EMAP has carried out regional-scale studies, on both terrestrial and aquatic species. The data
collected for EMAP-Estuaries, to quantify conditions in coastal regions of the United States, are
useful to the Great Waters. Sampling and subsequent analyses in EMAP studies are generally
not directed at a specific waterbody, but encompass a larger geographic region, which may
include waterbodies of the Great Waters. These two projects provide information on assessing
the extent of pollutant contamination in U.S. waterbodies; however, the application of their
findings to individual waterbodies is limited since these projects were not designed to address
concerns specific to the Great Waters.
NS&T MUSSEL WATCH PROJECT
Systematic Sampling Approach
The Mussel Watch project is designed to
provide long-term and large-scale monitoring of
pollutant distribution, looking for temporal (not
spatial) trends. The sampling design is set up to
be representative of large areas rather than small-
scale patches of contamination. The objective is
to get a representative picture of the general or
"average" conditions of the U.S. coastal waters.
Therefore, a systematic sampling approach is
used. Also, it is useful for estimating statistically
the average concentration of pollutants when
general trends or patterns in concentration are
known from other sources of information.
Initiated in 1986, this continuing
project is directed at tracking temporal trends
in concentrations of pollutants (e.g., PAHs,
PCBs, pesticides, metals) found in whole soft-
parts of mollusks at about 255 coastal and
estuarine sites on the Atlantic, Pacific, and Gulf
coasts (including Great Waters such as
Chesapeake Bay and Galveston Bay).
Since no single species of mollusk is
common to all waters, a number of species
have been sampled for this project, including
several common to the Great Waters — blue
mussels (Mytilus edulis) from the Northeast
and West Coasts, American oysters (Cmssostrea
virginica) from the Mid-Atlantic and Gulf coasts, and zebra mussels (Dreissena polymorpha) from
the Great Lakes. Mussels and oysters are useful for monitoring changes in the pollutant levels
because they remain at fixed sites, and concentrations in their tissues reflect, in general, changes
in the concentrations in the surrounding water. There are species differences, so data need
careful interpretation. Sampling for this project is performed during the same season each year
to reduce the influence of seasonal cycles on natural factors (e.g., salinity, reproductive state).
Sites that were selected support adequate populations of these mollusks such that sufficient
samples are available annually over many years (O'Connor 1992; O'Connor and Beliaeff 1995).
Table 11-7 is a general representation of the pollutant trends in mollusks during the 1986-
1993 period at Great Waters sites based on analysis of data collected for the Mussel Watch Project
(O'Connor and Beliaeff 1995). All of the trends shown in Table 11-7 are statistically significant
(confidence level of 90 percent and above); however, quantitative information regarding the
changes in pollutant levels was not provided by O'Connor and Beliaeff (1995). Consequently,
the magnitudes of the increases or decreases cannot be compared between sites (i.e., one cannot
determine which sites showed the most improvement). However, useful information regarding
general pollutant trends is presented.
As shown in Table 11-7, most of the Great Waters sites did not exhibit a statistically
significant trend or change in pollutant levels in mollusk tissues during the eight-year period.
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CHAPTER II
CONTAMINATION OF BIOTA
Trends, when present, were mainly downward since 1986 (i.e., for cadmium, PCBs, DDT, PAHs,
chlordane, and dieldrin). According to the investigators, decreases in levels of these chemicals
are probably the result of bans on the use of chlorinated hydrocarbons and the reduced use of
certain pollutants (O'Connor and Beliaeff 1995).
The level of mercury in mollusks showed an increasing trend over the eight-year period
only in one Galveston Bay site (O'Connor and Beliaeff 1995). During the four-year period from
1986 to 1990, mercury concentrations increased at several other sites (O'Connor 1992); however,
mercury levels stabilized at these sites by 1993 so that no statistically significant trend was
apparent over the eight-year period (O'Connor and Beliaeff 1995). Lead levels in mollusks also
exhibited an increasing trend at one site in Galveston Bay and one site in Tampa Bay during the
eight-year period (O'Connor and Beliaeff 1995); however, no change in lead levels was evident at
these sites between 1986 and 1990 (O'Connor 1992). The investigators concluded that because
the high concentrations of mercury and lead were found, for the most part, in the vicinity of
population centers, they may be attributable to human activities (O'Connor and Beliaeff 1995).
The information presented in Table 11-7 and discussed above focuses only on trends in
contaminant levels in mollusks based on the Mussel Watch Project data. For the pollutants that
show no significant trends over the eight-year period, it does not necessarily mean that no
changes are occurring with respect to contamination of biota at Great Waters sites. Other
analyses of the Mussel Watch Project data may indicate different patterns of pollutant
concentrations in mollusks. In addition, gamefish and fish-eating birds and mammals are much
higher in the food web than mussels and oysters, and therefore, may exhibit different patterns of
pollutant concentrations in their tissues.
TABLE 11-7
Eight-Year Trends of Pollutant Concentrations in Mussel Watch Project (1986-1993)
Waterbodies
(number of sites examined)
Chesapeake Bay
(5 sites)
Delaware Bay
(4 sites)
Long Island Sound
(9 sites)
Narragansett Bay
(2 sites)
Tampa Bay
(3 sites)
Galveston Bay
(6 sites)
Contaminant Trend (number of sites affected)3
Mercury
«(5)
«(4)
«(9)
«(2)
«(3)
T(1)
«(5)
Lead
«(5)
«(4)
1(1)
«(8)
i(1)
«(1)
T(1)
«(2)
T(1)
«(5)
Cadmium
i(1)
«(4)
i(1)
«(3)
i(4)
«(5)
"(2)
«(3)
«(6)
PCB
1(3)
«(2)
1(2)
«(2)
1(5)
«(4)
«(2)
1(1)
«(2)
1(2)
«(4)
DDT
1(3)
«(2)
"(4)
1(2)
«(7)
"(2)
1(1)
«(2)
1(1)
«(5)
PAH
"(5)
"(4)
1(1)
«(8)
"(2)
"(3)
"(6)
Chlordane
1(4)
«(1)
1(1)
«(3)
1(3)
«(6)
«(2)
1(2)
«(1)
1(4)
«(2)
Dieldrin
1(3)
«(2)
«(4)
1(1)
«(8)
"(2)
«(3)
1(3)
«(3)
a Represents trends in annually measured concentrations of contaminants in mollusks over 8-year period; trend indicated by
arrow (i.e., i = decreasing trend; T = increasing trend; « = no trend). Number of sites showing trend within each waterbody is
indicated in parentheses. Sites were sampled in at least six of the eight years. All trends shown are statistically significant.
Adapted from O'Connor and Beliaeff (1995).
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CHAPTER II
CONTAMINATION OF BIOTA
EMAP-ESTU ARIES
One goal of EMAP is to
quantitatively evaluate the condition of
environmental conditions: hypoxia (low
oxygen levels), sediment contamination,
coastal eutrophication, and habitat loss. A
probability-based approach is used, which
EMAP is a national program initiated in 1989 in
response to the EPA Science Advisory Board's
coastal estuaries, by investigating several . .. . ......
J oo recommendation to monitor the status and trends
of the U.S. ecological resources -terrestrial,
freshwater, and marine. The program is directed
by EPA's Office of Research and Development,
with participation by other federal agencies (e.g.,
„ ,. , , , j ,,, NOAA, U.S. Forest Service, U.S. Fish and Wildlife
allows estimates to be made of the Service)
uncertainty associated with assessments and
improves the ability to identify ecological
responses to pollution. Of interest to the Great Waters are the EMAP-Estuaries results obtained
for the Virginian Province (Cape Cod to the Chesapeake Bay) and Louisianian Province (Texas to
west coast of Florida). Statistical data collected provide primarily quantitative information on a
regional scale.
Results are available for the Virginian Province for 1992 (trend data for 1990-1993 are
currently being analyzed), which include sampling results for two relevant Great Waters sites,
the Chesapeake Bay (as well as connecting tributaries and small water systems) (53 sampling
stations) and Long Island Sound (14 stations). Together, the two waterbodies represent
approximately 63 percent of the surface area of the entire province. One of the environmental
indicators assessed in the study was sediment contamination. Results showed that metal
concentrations in the sediment for the Chesapeake Bay were similar to the concentrations for the
overall Province (=24 jug/g for lead; =0.054 jug/g for mercury; =0.206 jug/g for cadmium). In Long
Island Sound, the concentrations of some metals in the sediment (44.2 yug/g lead; 0.088 /u,g/g f°r
mercury) were higher than those reported for the Chesapeake Bay and the overall Virginian
Province. These results suggest that Long Island Sound exhibits slightly higher contamination of
some metals in sediment compared to most other waterbodies in the east coast of the United
States. Comparing results among specific waterbodies within the regional area is limited because
the density of sampling points was not designed to thoroughly characterize each waterbody
separately. Also, uncertainty exists in the analysis of these waterbodies due to the short data
collection period (one year) (Strobel et al. 1994).
Biota Contamination by Major Waterbody
This subsection presents information from some monitoring studies and investigations
of the pollutant levels in tissues of biota living in the Great Waters. These studies, most of which
measure concentrations of metals and organochlorines in fish, provide evidence that toxic
contamination is occurring in biota from these waters. In most instances, the researchers focused
on pollutant levels in tissues of the biota, and did not look for toxic lesions or other adverse
effects. Nevertheless, some of the long-term studies provide information on potential
contamination trends in the species examined. In addition, studies that monitor toxic
contamination in sediment are presented because contaminated sediment may be a long-term
source of pollutant exposure to the aquatic biota and food web. These studies suggest
continuing contamination in the waterbody.
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CHAPTER II
CONTAMINATION OF BIOTA
GREAT LAKES
Contaminant concentrations in
gamefish from the open waters of the Great
Lakes have been monitored for over 20 years
and provide one of the most extensive data
bases on trends of environmental
contaminants in organisms at the upper end
of the food web. Three monitoring efforts
that data have come from include: (1) lake
trout monitored by Fisheries and Oceans
Canada; (2) lake trout and walleye
cooperatively monitored in U.S. waters by
EPA's Great Lakes National Program Office,
U.S. National Biological Service, and the
Great Lakes States; and (3) coho salmon
fillets cooperatively monitored in U.S. waters
by the Great Lakes States, FDA, and EPA's
Great Lakes National Program Office.
PCB Contamination in
Great Lakes Biota
Lake Trout/Walleye. During the period 1977-
1992, PCB concentrations in lake trout, as well as
walleye in Lake Erie, declined significantly, but in
recent years, concentrations have generally
remained stable or increased slightly in Lakes
Michigan, Huron, Superior, and Erie.
Coho Salmon. PCB concentrations in coho
salmon collected from Lake Michigan declined
from 1.9 ^g/g (1980) to 0.38 //g/g (1983), but then
increased to 1.09^g/g (1992). A similar pattern
was observed in Lake Erie and the upper reaches
of the Saint Lawrence River.
Herring Gull Eggs'. Monitored since 1974, the
greatest decline in PCB contamination in herring
gull eggs occurred between 1974 and 1981.
Since then, the rate of decrease has leveled off,
and by 1991, slight increases were reported in the
levels of some PCBs.
Sources: De Vault et al. 1995, 1996.
These monitoring efforts have
demonstrated that, while significant declines
in PCB and DDT concentrations in lake trout,
walleye, and coho salmon have been
observed over the past two decades, the
amount of residues of PCBs and DDT in
these fish have leveled off or even increased slightly in the last ten years (De Vault et al. 1995,
1996) (see sidebar). This change in trend has occurred despite declining ambient water
concentrations of PCBs. A similar trend has been noted in the levels of PCBs and DDT in herring
gull eggs, which have been monitored by the Canadian Wildlife Service since 1974.
Lake condition changes can complicate pollutant contamination issues. The strong
correlation between trends in DDT and PCBs suggests that changes in the composition of the
food web (or trophic structure) may be partly responsible for increases in contaminant
concentrations at the upper end of the food web (i.e., gamefish) (De Vault et al. 1995,1996). For
example, research by Haffner (1994) and Stow et al. (1995) on the exposure dynamics of organic
pollutants in Lakes Erie and Michigan suggests that changes in the food web could be the cause
of the observed increase in PCB contamination in biota. Large, regional pools of PCBs can be
reintroduced from sediments by benthic organisms. Changes in the species composition at the
mid-trophic levels of the food web may biomagnify greater amounts of PCBs to higher trophic
levels. Increased PCB levels in certain predator fish also may be due to reductions in their
growth rate.
Evidence of changes in the exposure dynamics of organic contaminants has been
observed in the western basin of Lake Erie with the invasion of zebra and quagga mussels
(Haffner 1994). These mussels increase biomagnification of pollutants in the benthic food
web by consuming significant amounts of phytoplankton that are contaminated with
pollutants. The major predator of the zebra mussel is the drum (a low-trophic level fish),
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CHAPTER II
CONTAMINATION OF BIOTA
which in turn is a preferred prey of the herring gull. By concentrating contaminants contained
in phytoplankton and other suspended organic particles, zebra and quagga mussels can cause
PCB levels in certain fish and in herring gulls to increase even though ambient water
concentrations of contaminants are decreasing.
Sediment Core Data in the Great Lakes
Atmospheric pollutant loadings into the Great
Lakes region are estimated from mass balance
studies and modeling data, although indirect
measures of contaminant loadings, such as
sediment core data, are also desirable. Recent
measurements of sediment core data have shown
declining concentrations of PAHs in Lake
Michigan, PCBs and DDT in Lakes Michigan and
Ontario, and lead and mercury in Lakes Superior,
Michigan, and Ontario. Comparison of sediment
data between the Great Lakes provides additional
information on sources of loadings. For example,
toxaphene has long been thought to result from
long-range atmospheric transport from the
southeastern U.S.; however, sediment cores from
Lake Superior and upper Lake Michigan suggest
little decline in toxaphene (contrary to declines
observed for DDT, mercury, and PCBs in these
lakes). Efforts are underway to examine this
issue.
Sources: De Vault et al. 1995; Simcik et al. 1996.
The three monitoring programs
discussed above also provide information on
the levels of two pesticides, dieldrin and
toxaphene, in upper trophic-level fish from
the Great Lakes. Dieldrin concentrations
have exhibited a general pattern of decline in
the Great Lakes since the 1970s (De Vault et
al. 1995,1996). Peak levels were noted in
1979 in Lakes Michigan, Superior, Huron,
and Ontario and again in 1984 in Lakes
Superior, Huron, Ontario, and Erie.
Toxaphene concentrations are highest in lake
trout from Lakes Michigan and Superior and
lowest in lake trout from Lakes Erie and
Ontario (De Vault et al. 1996). Lake trout
from Lake Michigan sampled between 1982
and 1992 suggest declining levels of
toxaphene during this period; however,
there was no significant change in
concentrations of Lake Superior lake trout
(Glassmeyer et al. 1997). A similar trend was
observed in rainbow smelt. The drop in
toxaphene concentrations coincides with the
U.S. ban on toxaphene in 1982. The investigators speculate that the lack of decline in Lake
Superior is due to either a lake-specific source that continues to load toxaphene into Lake
Superior or a slower removal rate in Lake Superior compared to the other Great Lakes (more
discussion in Section IV.A on the Great Lakes).
In contrast to the monitoring studies of gamefish, monitoring of forage fish provides an
indication of contamination at lower levels of the food web. Rainbow smelt have been routinely
monitored in Lakes Superior, Huron, Erie, and Ontario by Fisheries and Oceans Canada since
1977. During this time, concentrations of PCBs, mercury, and total DDT have declined signifi-
cantly in smelt from these lakes (De Vault et al. 1995). Smelt from Lake Ontario consistently have
the highest tissue concentrations of PCBs (~0.5-2.25 yug/g) and total DDT (—0.15-0.6 yug/g), while
those from Lake Superior have the highest mercury levels (—0.02-0.1 /ag/g).
Contaminant concentrations in young-of-the-year spottail shiners are useful indicators
of local, recent pollutant inputs into aquatic ecosystems because they do not travel extensively
during their first year of life. Surveillance of these fish by the Ontario Ministry of Environment
and Energy (primarily in Canadian waters) has shown a general decline in tissue PCB and DDT
concentrations (De Vault et al. 1995). Contaminant levels also have been assessed in young-of-
the-year fish from the New York waters of the Great Lakes (Skinner et al. 1994). Elevated
concentrations of PCBs were found mainly in fish from the St. Lawrence River drainage area
-34-
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CHAPTER II
CONTAMINATION OF BIOTA
below the Moses-Saunders Dam in Massena; these levels were attributed to industrial activities
in the area. Levels of mercury in these fish were low (<100 ng/g).
Zebra mussels have been considered to be potential system-wide biomonitors of organic
contamination trends in the Great Lakes (Comba et al. 1996). Researchers collected and analyzed
specimens from 24 sites in Lake Erie, Lake Ontario, and the St. Lawrence River between 1990 and
1992 for residues of PCBs and organochlorine pesticides. Mean concentrations of 154 ng/g total
PCBs, 8.4 ng/g total DDT, and 3.5 ng/g total chlordane (whole mussel dry weight basis) were
reported. Concentrations varied greatly between sites (e.g., 22-497 ng/g total PCBs), which the
researchers attributed to the sensitivity of these mussels to different levels of contamination
(Comba et al. 1996). The investigators also indicated that the observations of spatial contaminant
trends in the study were similar to findings from other biomonitoring programs.
LAKE CHAMPLAIN
Current efforts to monitor toxic pollution in Lake Champlain have focused on fish and
sediment contamination by metals and organic compounds. The Vermont Department of
Environmental Conservation implemented a study to analyze soft tissue from mussels (Elliptio
complanata) as a bioindicator for the lake. Mussels were collected at mouths of several Lake
Champlain tributaries; chlordane and PAHs were detected in the mussels (LCBP 1994). In 1987-
1988, the States of Vermont and New York analyzed fish tissue collected from Lake Champlain
for 17 contaminants. Elevated levels of PCBs were found in large lake trout and in American eel
and brown bullhead. The findings of this study led, in part, to health advisories being issued
against eating these fish species in Lake Champlain (LCBP 1994).
Because of elevated levels of pollutants in Lake Champlain, the Lake Champlain
Sediment Toxics Assessment Program was initiated (Mclntosh 1994). Pollutants that were
measured included trace metals (cadmium, mercury, lead) and organic compounds (PCBs, PAHs,
dioxins/furans). Pollutant levels were measured at nine sites during 1991 and 1992. Findings
after the end of the first phase (May 1993) provided little evidence of widespread high-level
contamination (although high levels of PCBs and PAHs were measured in sediment near two
dock sites). The study did find widely varying patterns of contamination. It appears that, at
some sites, some pollutants had higher concentrations in the deeper layers of the sediments, with
the upper layers of sediment showing less contamination, while other pollutants exhibited a
reversal of this pattern (Mclntosh 1994); however, the investigator did not provide an
explanation for this deposition pattern. The local and/or regional source of the contamination is
not known.
As part of the Lake Champlain Sediment Toxics Assessment Program, a biological
assessment of the contaminated sediments was also performed (Mclntosh 1994). Most of the
year, lake trout do not inhabit bottom waters near the sediment-water interface. However,
concerns exist for the mechanisms that may link lake trout to PCB-contaminated sediment. This
issue was evaluated by looking at one possible link, the freshwater shrimp Mysis relicta (or
mysids). Mysids are believed to be a major component in the Lake Champlain food web, and the
high lipid content of these organisms make them potential accumulators of PCBs. Laboratory
experiments demonstrated that exposure to PCB-contaminated sediment results in high levels of
PCBs in the mysids (Mclntosh 1994). However, there was no attempt to predict the potential of
mysids to redistribute PCBs within the sediments in Lake Champlain.
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CHESAPEAKE BAY
Adverse effects that could be related to pollutants accumulating in the tissues of
organisms, such as reduced growth, reproduction effects, and tumor development, have been
reported in aquatic organisms in a variety of habitats in the Bay from the 1980s to the early 1990s.
The Chesapeake Bay Program has sponsored forums to assess contaminant levels in biota and to
reach a consensus regarding the trends in the pollutants found in biota and in sediment. While
significant declines in metal contamination of fish tissue have been observed over the past two
decades, elevated metal concentrations have been measured in fish in specific, more
industrialized areas of Chesapeake Bay (CBP 1994b).
Studies conducted from 1970 to 1992 show that chemical contamination has caused
various effects to wildlife in the Chesapeake Bay during the 1970s and 1980s (CBP 1994b). In
1991, the Status and Assessment of Chesapeake Bay Wildlife Contamination Forum was held to critically
review data on the effects of exposure and uptake of pollutants on Chesapeake Bay basin birds,
mammals, reptiles, and amphibians. The committee concluded that there was little evidence to
suggest pollutants were posing a serious direct hazard to birds in the early 1990s. Instead, it is
more likely that indirect effects on wildlife habitats and food sources (e.g., excessive nutrients,
suspended sediments, herbicides) have greater impacts on bird populations. The forum found
that there were insufficient information available at the time to fully assess potential adverse
impacts of chemical contamination on mammalian, reptile, and amphibian populations in the
Chesapeake Bay basin (CBP 1994b). Due to more recent scientific information on some
pollutants' mechanisms of action such as endocrine disruption (see Sections II.C and II.D), the
conclusions of the 1991 forum may need to be reevaluated with more current data on pollutant
contamination in Chesapeake Bay biota.
In 1993, the Chesapeake Bay Finfish and Shellfish Tissue Contamination Critical Issues Forum
was held to address the following issues: (1) magnitude and extent of fish and shellfish contam-
ination in the Chesapeake Bay and its basin; (2) impact (i.e., bioaccumulation, toxicity) of the
contamination at basinwide, baywide, regional, or local scales; and (3) comparison of the contam-
ination to that of other waterbodies (e.g., Puget Sound, Great Lakes) (CBP 1994b). The data com-
piled by the forum indicate that finfish and shellfish tissue contaminant concentrations declined
significantly after the 1970s for several metals, pesticides, and organic chemicals. For fish species
combined, concentrations of PCBs and DDT in fish liver tissue are in the low range relative to
national data. However, at the species-specific level, Atlantic croaker and spot collected from
1984 to 1987 had levels of chlordane, PCBs, dieldrin, and total DDT in the liver above the national
average and national median for these species. Lead and mercury concentrations in croaker
livers were generally above the national average and national median, while lead concentrations
in spot livers were sporadically high. The concentrations of PCBs, chlordane, dieldrin, DDT,
cadmium, and mercury in oysters in the Chesapeake Bay have declined between 1986 and 1991.
Levels of mercury, chlordane, toxaphene, and PCBs in finfish from the Chesapeake Bay basin "hot
spots" (e.g., Baltimore Harbor, Back River) are generally well below those found at other areas
considered contaminated (e.g., New York/New Jersey Harbor, Lake Michigan, Boston Harbor).
OTHER COASTAL AREAS
Several monitoring studies of biota contamination also have been performed in other
coastal waterbodies of the Great Waters. Some relevant findings are highlighted below;
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however, additional research is needed to provide a more complete picture of biota
contamination in some of these coastal areas.
4 Galveston Bay. There is little information about historical trends and concentrations of
pollutants in aquatic organisms from Galveston Bay. For this reason, the Galveston Bay
National Estuary Program initiated a study to characterize pollutant contamination in
edible fish and shellfish in the bay. Between 1991 and 1993,14 fish species, two shellfish
species, and three bird species were sampled for numerous pollutants, including several
Great Waters pollutants of concern. No "hot spots" of biota contamination were detected
and the fish tissue concentrations rarely exceeded FDA criteria for these contaminants
(Brooks et al. 1992). The study did not evaluate dioxins, but fish consumption advisories
to protect the general population currently exist for dioxins in Galveston Bay.
4 Tampa Bay. Tissue concentrations of organic compounds and trace metals in Tampa Bay
oysters (C. Virginica) (sampled between 1986 and 1989) were compared to reported levels
for adverse effects to mussels at other sites (Long et al. 1991). The average concentration
of total PCBs in the Tampa Bay oysters collected over four years was 0.15 ppm dry
weight; total PCB concentration of 0.18 ppm or greater occurred in 11 of 55 samples.
Investigators determined that, for total PCBs, adverse effects (e.g., reproductive effects,
cellular damage, and biochemical changes) in mussels were associated with tissue
concentrations of 0.18 to 1.43 ppm dry weight. The average concentration of mercury in
the Tampa Bay oysters collected over four years was 0.27 ppm dry weight; mercury
concentration of 0.4 ppm or greater occurred in 13 of 55 samples. Adverse effects (e.g.,
pathological and enzymatic responses) in mussels were associated with mercury tissue
concentration of 0.4 ppm dry weight. Based on these data, Long et al. (1991) concluded
that the PCB and mercury concentrations in some oysters in Tampa Bay may be
sufficient to cause potential adverse biological effects.
4 New York-New Jersey Harbor and New York Bight. In 1993, 23 species of fish, six species of
bivalves, two species of crustaceans, and one species of cephalopod were collected from
six areas of the New York-New Jersey Harbor, including the New York Bight Apex
(Skinner et al. 1996). The samples were analyzed for contaminants, including PCBs,
organochlorine pesticides, and mercury. Of these compounds, PCBs were the primary
chemical contaminants of concern. Average total PCB concentrations for American eel,
striped bass, white perch, bluefish, rainbow smelt, and the hepatopancreas of blue crab
and American lobster in one or more areas of the harbor estuary exceeded the FDA
tolerance level for PCBs (2,000 ng/g). In blue crab and American lobster, PCB and
organochlorine pesticide residue concentrations were particularly elevated in tissues
with high lipid content (e.g., hepatopancreas). The researchers noted that although
relatively low levels of contamination were found in muscle tissue, increased
contaminant levels in the hepatopancreas may present a substantially increased risk to
those people who choose to eat this tissue (Skinner et al. 1996). PCB concentrations were
highest in the Hudson River and Upper Bay, the East River, and the Arthur Kill-Kill Van
Kull-Newark complex; concentrations were lowest in Jamaica Bay and the New York
Bight Apex. The principal components of the PCB concentrations observed were the
higher chlorinated congeners.
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Residues of certain other contaminants (e.g., DDT, chlordane, dieldrin, and mercury)
also exceeded regulatory criteria in some fish tissue samples (Skinner et al. 1996).
Analyses were performed for hexachlorobenzene and toxaphene, but they were seldom
or never detected.
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II.C Ecological Effects
This section is intended to provide a brief overview of the current literature on the
potential ecological effects (generally, adverse effects to aquatic organisms, birds, and mammals)
from exposure to the Great Waters pollutants of concern. In general, the information presented
in this section represents data published since the background document from the First Report to
Congress on exposure and effects (Swain et al. 1992a) was completed through 1995. Because the
information presented in this report covers only recent studies, it cannot be used alone to
determine whether these effects are widespread in the environment. As in the First Report to
Congress, the contribution of atmospheric deposition to toxic contamination and potential
ecological effects associated with exposure to the pollutants cannot be quantified at this time.
This section presents information on effects observed in both laboratory and field
studies; it does not, however attempt to establish a relationship between the two types of studies.
This section also does not provide information on the exposure levels of the pollutants
responsible for the observed effects. In addition, this section does not distinguish effects that
may occur in wildlife with long-term exposure to the pollutants of concern from effects caused
by acute, high-level exposures (e.g., accidental spills). The potential effects of a pollutant may
vary with duration of exposure, possibly due to a breakdown of the chemical in the body to
another chemical that is more toxic or affects other target organs than the exposed chemical.
Furthermore, adverse effects on ecological health caused by exposure to toxic contaminants are
not often easy to distinguish from other stresses. For example, fish populations in the Great
Lakes suffer from habitat loss, overfishing, and the introduction of non-native species, in
addition to the effects from toxic contaminant exposure (U.S. EPA 1995a). Finally, studies on
ecological effects generally do not determine the exposure pathway of the pollutants (e.g.,
atmospheric deposition). In this report, under future directions for research, EPA recommends
coordinated analyses of persistent pollutants that relate field measurements of concentrations to
estimated exposure and associated effects observed in biota.
Conclusions from the First Report to Congress
Information from the First Report to Congress is presented here to provide a foundation
for the subsequent discussion of the recent information available for this report. The First Report
to Congress, as well as the background document on exposure and effects (Swain et al. 1992a),
identified many adverse ecological effects, at both the individual species level and the ecosystem
level, associated with the pollutants of concern. In addition, the First Report to Congress
discussed eutrophication of estuarine waters, which is the main ecological effect relevant to this
report associated with nitrogen loading. Research findings and studies presented in the First
Report to Congress led to the following general conclusions concerning potential ecological
effects:
4 The selected pollutants of concern have been linked to a broad range of effects at the
individual species level in aquatic organisms and other wildlife, including effects on the
reproductive, nervous, immune, and endocrine systems, and changes in enzyme
functioning.
4 Reproductive effects of certain pollutants of concern include reduced fertility, increased
embryo toxicity, reduced hatchability, reduced survival of offspring, abnormalities in
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CHAPTER II
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Pollutants of Concern for Reproduction
Pollutants of concern that have been linked
with reproductive impairment in aquatic and
terrestrial wildlife include cadmium, DDT/DDE,
dieldrin, lead, lindane, mercury, PCBs, and
2,3,7,8-TCDD.
offspring, parental behavior change,
and changes in mating behavior
(e.g., impaired hormone activity,
changed adult sexual behavior). For
example, eggshell thinning in a
number of bird species and
associated reproductive loss were
linked to exposure to DDT (and its
metabolite DDE) in the 1960s and
1970s. Recent decreases in environmental concentrations of reproductive pollutants of
concern, such as DDT and PCBs, are correlated with population recoveries in many bird
and other wildlife species; however, some populations in certain regions of the Great
Lakes still exhibit higher rates of reproductive failure than in other areas.
Effects on the nervous and endocrine systems may occur at very low exposure levels.
For example, wild populations of Great Lakes herring gulls, Forster's terns, and ring-
billed gulls exposed to various pollutants of concern have exhibited behavioral changes
such as female-female pairings, which result in abnormal incubation activities and
nesting behavior, including nest abandonment.
Several of the pollutants of concern cause changes in enzyme functioning. Studies
reported that the activity of enzymes responsible for the breakdown of foreign
compounds is greatly increased by most of the pollutants of concern. In fish, the
increased activity of these enzymes has been shown to result from exposure to PCBs and
PAHs. In birds, "wasting" syndrome (i.e., the condition in which an animal slowly loses
body weight until it can no longer sustain itself) has been related to altered enzyme
activity resulting from exposure to pollutants such as TCDD.
Exposure of communities of bottom-dwelling aquatic species in the Great Lakes to toxic
chemicals has resulted in significant changes in species diversity and populations. In
addition, fish-eating birds such as bald eagles, herring gulls, and Forster's terns in the
Great Lakes region have undergone significant population declines since the 1960s.
Only in recent years, as water concentrations of pollutants in the Great Lakes have
declined, have some species begun to recover. Certain current population recoveries of
fish-eating birds are still dependent on migration to Great Lakes breeding colonies from
other areas.
Eutrophication8 is one of the most serious pollution problems facing estuarine waters of
the United States. Atmospheric deposition of various nitrogen compounds (mostly
nitrates and ammonium) can contribute significantly to eutrophication in coastal waters
where productivity is usually limited by nitrogen availability. Accelerated eutrophi-
cation results in severe ecological effects such as nuisance algal blooms, dieback of
underwater plants (due to reduced light penetration), reduced oxygen levels in the
water, and reduced populations of fish and shellfish. The reduction in oxygen levels
8 Eutrophication is an overabundance of nutrients (e.g., nitrogen) in a water body. It is a natural process that
typically takes place over hundreds of years, but can be greatly accelerated by additions of nutrients from human
activities.
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CHAPTER II
ECOLOGICAL EFFECTS
may reduce or eliminate bottom-feeder populations, create conditions that favor
different species, or cause dramatic fish kills, resulting in an altered food web.
The remainder of this section presents updated information on ecological effects
associated with the Great Waters pollutants of concern.
Current Understanding of Ecological Effects
Since the First Report to Congress, updated information on the pollutants of concern
and their effects on aquatic and terrestrial wildlife has become available. This section first
discusses some notable research efforts on ecological effects relevant to some Great Waters
pollutants of concern and then provides a brief overview of recent data on the potential
ecological effects specific to each pollutant of concern.
As introduced in the First Report to Congress, the role of endocrine disrupters in causing
adverse effects wildlife and humans is an emerging and controversial issue. Endocrine
disrupters were termed "environmental estrogens" in the First Report to Congress; however,
because the interference with hormone action was found not to be limited to estrogen, these
pollutants are now more generally referred to as "endocrine disrupters." For example, p,p'-DDE
(a breakdown product of DDT) has been shown to inhibit the binding of androgen, a male
hormone, to receptors, among other androgen actions (Kelce et al. 1995). Several pollutants have
been identified as possible endocrine disrupters, including 11 of the 15 pollutants of concern for
atmospheric deposition to the Great Waters: chlordane, dieldrin, DDT/DDE, hexachlorobenzene,
lead, lindane, mercury (in the form dimethylmercury), PCBs, TCDDs, TCDFs, and toxaphene
(e.g., Cassidy et al. 1994; Chowdhury et al. 1993; Colborn et al. 1993; McKinney 1994; Soto et al.
1994; U.S. EPA 1994c). Since the First Report to Congress, scientific research on endocrine
disrupters has continued to provide evidence of their adverse effects and has investigated their
mechanisms of action (i.e., how they disrupt the endocrine system within the body).
The existence and effects of the hormone-like action of environmental pollutants were
first hypothesized in the 1950s and 1960s. In the late 1980s, scientists concerned with noncancer
effects of toxic pollutants brought this issue into focus. In July 1991, many scientists whose
diverse research interests touched on some aspect of endocrine system disruption convened at
the Wingspread Conference. The conference helped identify future research needs for
improving the understanding of endocrine disrupters, their mechanisms of action, and their
effects (NWF 1994). Many of the adverse effects in wildlife and humans (e.g., reproductive,
developmental, and immunological effects) associated with the pollutants of concern are now
theorized to be associated with the endocrine-disrupting action of the pollutants. Recent articles
published in the mass media have brought this issue widespread attention (Begley and Click
1994; Suplee 1996; Weiss 1994; Weiss and Lee 1996).
Endocrine disrupters are believed to interfere with the operation of the endocrine
system in many ways, such as by mimicking natural hormones or by blocking natural hormones.
This interference can potentially disrupt the reproductive and immune systems and adversely
affect metabolism, growth, and behavior.
Some of the recent articles demonstrating endocrine disruption by a few of the Great
Waters pollutants of concern in aquatic and terrestrial wildlife are briefly summarized below.
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CHAPTER II
ECOLOGICAL EFFECTS
4 Scientists in central Florida have been observing alligators from a contaminated lake and
a control lake. The researchers have found that alligator eggs and newborns from the
contaminated lake differ significantly from those in the control lake, showing reduced
hatchability, reduced viability of offspring, endocrine "demasculation" of males, and
"superfeminization" of females (Guillette et al. 1994). Juvenile alligators exhibit
significantly smaller penis size (24 percent decrease) and lower plasma concentrations of
testosterone (70 percent lower) when compared to alligators from the control lake
(Guillette et al. 1996). The alligators from the contaminated lake have elevated levels of
p,p'-DDE, a known endocrine disrupter, in their tissues, which researchers believe are
associated with a large spill of a pesticide containing DDT. Studies into the mechanism
of action of these effects are ongoing (Guillette et al. 1995,1996).
4 Researchers have been studying the mechanism of action of endocrine disruption in a
common turtle species (the red-eared slider) and the African clawed frog (Palmer and
Palmer 1995). Their work has focused on a potential biomarker for exposure to endo-
crine disrupters called vitellogenin (egg-yolk protein in the blood of egg-laying verte-
brates). When stimulated by estrogen, the liver produces this protein and releases the
protein into the bloodstream, where it then circulates to the ovaries and is deposited into
an egg. Usually only females possess a sufficient amount of estrogen to produce vitel-
logenin; however, in a laboratory study, DDT induced vitellogenin production in male
turtles and frogs. In another study, PCBs and lindane were found to induce estrogen
receptor and vitellogenin accumulation in rainbow trout liver (Flouroit et al. 1995).
4 In many egg-laying reptiles, the temperature of the incubating egg determines the sex of
the offspring. PCBs applied to the shells of turtle eggs during the period of sexual
differentiation counteracted male-producing temperatures and induced ovarian
development (Bergeron et al. 1994). Further study of the mechanism of action and
synergistic effects of different PCB congeners are ongoing (Crews et al. 1995).
4 Researchers have recently been testing the hypothesis that endocrine disrupters, such as
DDE, mercury, and PCBs, are playing a role in the decline of the endangered Florida
panther population (Facemire et al. 1995). (Many have considered inbreeding the main
factor up to this point.) A large percentage of males have exhibited abnormal reproduc-
tive organs, sterility, and production of abnormal or deformed sperm. Both males and
females exhibit abnormal hormone ratios, with little difference in estradiol levels
between males and females (i.e., evidence that males have been demasculated and
feminized).
4 The effluent from sewage treatment plants has been shown to induce vitellogenin
synthesis is male fish (Folmar et al. 1996; Sumpter and Jobling 1995). The investigators
attribute this effect to the estrogenic properties of environmental contaminants in the
effluent, though specific chemicals were not identified.
In recent years, several organizations and governmental agencies, including EPA, have
begun to support research efforts to further study endocrine disrupters. For example:
4 The National Science and Technology Council, which advises the President and his
Cabinet on directions for federal research and development efforts, has given EPA
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Research Planning Workshops on
Endocrine Disruptors
Purpose: To develop a national research strategy
on endocrine disrupters, in response to growing
public concern over their adverse effects.
Findings: The hypothesis that endocrine
disrupters cause a variety of adverse effects in
wildlife and humans is of sufficient concern to
warrant a concerted research effort. Research
priorities include: identifying and characterizing
effects on developing reproductive systems; and
refining exposure assessments and research on
toxicology of mixtures.
Outcomes: EPA has published workshop findings
and recommendations in scientific literature,
begun implementing some of the identified
research initiatives, and has formed an Endocrine
Disrupter Research Coordination Committee.
Sources: Ankley et al. 1997; CENR 1996; Kavlok
etal. 1996; U.S. EPA1995b.
the task of developing a national
research strategy on endocrine
disrupters by 1998. EPA recently
conducted two workshops to plan
research in this area (see sidebar).
4 The Chemical Industry Institute of
Toxicology (CUT) has developed a
comprehensive research program to
evaluate the potential for selected
chemicals to affect the human
endocrine system. One of the critical
goals of this program is to
understand the relationship between
dose levels that produce an effect in
laboratory cell cultures and the dose
level needed for effects to be seen in
laboratory animals.
4 EPA's Risk Assessment Forum, which
promotes scientific consensus on risk
assessment issues, assembled a
technical panel to study environmental endocrine disrupters. The panel has released a
draft report that is intended to serve as an interim assessment and analysis of the
environmental endocrine disruption hypothesis until a more extensive exploration of
the issue can be completed by the National Academy of Science (U.S. EPA 1996d).
In addition to the recent focus on endocrine disrupters and their potential impact on
ecological health, other research efforts relevant to potential ecological effects of the pollutants of
concern include the following:
4 EPA submitted a draft Mercury Study Report to the Science Advisory Board (SAB) for
review in June 1996. The report was reviewed by SAB in February 1997. EPA expects to
receive the opinion of SAB in the summer of 1997. The final Mercury Study Report will
fulfill the requirements of CAA section 112(n)(l)(B), including a requirement to assess the
environmental effects of mercury emissions.
4 Dioxin has been classified as the most potent known animal carcinogen, and as a
probable human carcinogen, since 1985. Increased concerns that dioxins in aquatic
environments may be a major contributor to overall human dioxin exposure through
fish and shellfish consumption, as well as increased evidence of its hazard to fish and
wildlife, prompted EPA to reassess dioxin's effects on aquatic ecosystems. Work on
characterizing ecological risks is in progress at EPA's Mid-Continent Ecology Division
of the National Health and Ecological Effects Research Laboratory (NHEERL) in
Duluth, Minnesota. EPA published the Interim Report on Data and Methods for
Assessment of2,3,7,8-Tetrachlorodibenzo-p-dioxin Risks to Aquatic Life and Associated
Wildlife (U.S. EPA 1993a) on this research. The goal of the report is to review and
evaluate relevant published and unpublished data and models currently available for
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ECOLOGICAL EFFECTS
analyzing dioxin exposure to and effects on aquatic life and wildlife. Information on
related compounds, such as TCDF and PCBs, is not discussed in detail in the interim
report; however, it is expected that the final report will assess the contribution of these
related compounds to the risk for aquatic life and wildlife. The interim report findings
are presented under the discussion of TCDD in this section.
Pollutants of Concern and Health Effects
in St. Lawrence Estuary Beluga Whales
A 9-year epidemiological study in an isolated
population of beluga whales documented higher
levels of many pollutants of concern, including
dieldrin, DDT, HCB, lead, mercury, PAHs, and
PCBs, in these whales compared to Arctic belugas
(Beland et al. 1993). The St. Lawrence whales
exhibited high prevalence of tumors; high incidence
of lesions to the digestive system, mammary glands,
and other glandular structures; some evidence of
immune system suppression; and frequent tooth
loss and gum disease. No such lesions were
observed in Arctic belugas or in other St. Lawrence
aquatic mammals (e.g., seals). Researchers
propose this case as a model for the potential long-
term consequences of pollutants in the environment
on human health (De Guise et al. 1995).
Based on information from the above
research on ecological effects of pollutants of
concern, as well as findings from recently
published data, a summary of the potential
ecological effects of the pollutants of concern
is presented in Table II-8. For each effect
attributable to a pollutant of concern, the
table identifies the organism type(s) in which
the effect has been observed (i.e., plants,
invertebrates, fish, amphibians/reptiles, birds,
and mammals). Table II-8 presents data on
the following types of effects: death; cancer;
reproductive/developmental, immunological,
metabolic/enzyme, and neurological/
behavioral effects; damage to the kidney,
liver, heart, lungs or gills, or gastrointestinal
tract; exterior changes; and decreased growth
or biomass. The information in this table is
based on both field and laboratory studies.
This report does not attempt to assess how the observed effects on individual animals
contributes to changes in species populations within an ecosystem or how the laboratory studies
relate to studies of effects observed in the environment. In addition, information on the
exposure levels related to these effects is not provided.
Following the table, recent information on the ecological effects of the pollutants of
concern is discussed by pollutant group. The ecological effects of nitrogen (i.e., eutrophication
and its consequences) also are discussed in this section.
MERCURY AND COMPOUNDS
The data presented in Table II-8 summarize the potential effects of mercury exposure on
plants, invertebrates, fish, birds, and mammals. A brief summary of some recent research
findings is presented below:
4 The effects of mercury on plants may include death, growth inhibition, leaf or root
damage, chlorophyll decline, and reduced photosynthesis (Godbold 1991; Lindquist
1991; Schlegel et al. 1987).
4 In fish and aquatic invertebrates, mercury exposure can cause death, reduced
reproductive success, impaired growth and development, and behavioral abnormalities
(U.S. EPA 1985).
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TABLE 11-8
Potential Effects of the Pollutants of Concern on Aquatic Life and Wildlife
Pollutant of Concern
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
HCB
a-HCH
Lead and compounds
Lindane
Mercury and compounds
PCBs
POM (PAHs)
TCDD (dioxins)
TCDF (furans)
Toxaphene
Potential Ecological Effects3
Death
IF
1 FABM
PI
B
PI FB
IFABM
1
1 FABM
P IFBM
1 FM
FBM
1 FABM
Cancer
M
M
M
FAM
M
Reproductive/
Developmental11
1 FB
IFABM
1 BAM
A
1 F
IFABM
1
IFABM
IFBM
IFBM
FBM
IFBM
Immunological
M
M
FA
F
B
FM
FBM
M
Metabolic/
Enzyme
FBM
1 M
IFBM
PFB
FBM
F
Neurological/
Behavioral
1 B
FBM
FB
B
1 B
FABM
1
IFBM
FBM
1 F
B
AFB
a Blank areas indicate that no data were found correlating the effect with the pollutant of concern (as opposed to data found indicating no
correlation between the effect and the pollutant of concern).
b Includes endocrine-disrupting effects.
Key: P = Plants I = Invertebrates F = Fish A = Amphibians/Reptiles B = Birds M = Mammals
Sources: Arkoosh et al. 1994; Baturo et al. 1995; Constable and Orr 1994; Di Pinto et al. 1993; Doust et al. 1994; Dunier and Siwicki 1994;
Eisler 1985, 1986a, 1986b, 1987a, 1987b, 1988, 1990; Eisler and Jacknow 1985; Ferrando et al. 1995; Fitchko 1986; Geyer et al. 1993;
Government of Canada 1994; Hermsen et al. 1994; Hill and Nelson 1992; Huggetetal. 1992; Johnson et al. 1993; Lahvis 1995; Malbouisson et
al. 1994; Schulz and Liess 1995; Tidou et al. 1992; Trust et al. 1994; and U.S. EPA 1993a, 1993b, 1993c.
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TABLE 11-8
Potential Effects of the Pollutants of Concern on Aquatic Life and Wildlife
(continued)
Pollutant of Concern
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
HCB
a-HCH
Lead and compounds'1
Lindane
Mercury and compounds'1
PCBs
POM (PAHs)b
TCDDs
TCDFs
Toxaphene
Potential Ecological Effects3
Kidney
Damage
B
M
FB
BM
FM
M
M
FB
Liver
Damage
M
FB
FB
B
BM
FM
FM
Heart
Damage
B
M
Lung/Gill
Damage
M
F
M
M
Gastrointestinal
Damage
M
AM
BM
M
M
F
External
Damage
B
FB
FBM
FM
FB
Decreased
Growth/Biomass
1 FB
IM
P
PI B
IM
1
1 FB
PI FB
FB
F
1 FB
a Blank areas indicate that no data were found correlating the effect with the pollutant of concern (as opposed to data found indicating no correlation
between the effect and the pollutant of concern).
b Also causes other noncancer effects in plants, such as leaf and root damage, chlorophyll decline, and reduced photosynthesis.
Key: P = Plants I = Invertebrates F = Fish A = Amphibians/Reptiles B = Birds M = Mammals
Sources: Arkoosh et al. 1994; Baturo et al. 1995; Constable and Orr 1994; Di Pinto et al. 1993; Doust et al. 1994; Dunier and Siwicki 1994; Eisler
1985, 1986a, 1986b, 1987a, 1987b, 1988, 1990; Eisler and Jacknow 1985; Ferrando et al. 1995; Fitchko 1986; Geyeretal. 1993; Government of
Canada 1994; Hermsen et al. 1994; Hill and Nelson 1992; Hugget et al. 1992; Johnson et al. 1993; Lahvis 1995; Malbouisson et al. 1994; Schulz and
Liess 1995; Tidou et al. 1992; Trust et al. 1994; and U.S. EPA 1993a, 1993b, 1993c.
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ECOLOGICAL EFFECTS
Effects of mercury on birds may
include death, liver and kidney
damage, neurobehavioral effects,
impaired growth and development,
and reproductive effects (Eisler 1987a;
MDNR 1993; Scheuhammer 1987,
1991). Reproductive effects are the
primary concern for avian mercury
poisoning and may occur at dietary
concentrations well below those that
cause overt toxicity.
Extensive research on the toxicity of
mercury to mammals indicates that
effects vary depending on the form of
mercury ingested, with
methylmercury being the most toxic
form. Methylmercury ingestion by
mammals may cause death,
neurological and behavioral effects, and damage to the heart, lung, liver, kidney, and
stomach (ATSDR 1992e).
OTHER METALS
Population-level Effects of Mercury
Studies conducted on various communities
have shown mercury to: (1) reduce species
diversity of freshwater, brackish-water, and soil
microbial communities; (2) reduce carbon fixation
in phytoplankton communities; and (3) change the
species composition of phytoplankton in an
aquatic community. Although clear causal links
between mercury contamination and population
declines in various wildlife species have not been
established, mercury may be a contributing factor
to population declines of the endangered Florida
panther and the common loon. Other researchers
have concluded, however, that mercury levels in
most areas are not sufficient to adversely affect
bird populations.
Sources: Barr1986; Ensoretal. 1992; FPIC
1989; Roelkeetal. 1991.
Cadmium. As shown in Table II-8, adverse effects from exposure to cadmium have been
demonstrated in invertebrates, fish, and birds. Recent studies have focused on the toxicity of
cadmium to aquatic species (Kraak et al. 1992; Weinstein et al. 1992) and the identification of
potential indicator species for cadmium exposure (Naimo et al. 1992). For example, researchers
concluded that accumulation of some metals contributes to lesions to the shell of blue crabs in
the Albemarle-Pamlico Estuarine System; however, the researchers did not observe this result for
cadmium and lead (Weinstein et al. 1992).
Lead. Many noncancer ecological effects are associated with lead exposure, as shown in
Table II-8. However, the availability of recent studies on the ecological effects of lead is limited.
Rather, there is a strong interest currently focused on the neurological and behavioral effects in
infants and children (see Section II.D). One recent study of fish demonstrated that exposure to
waterborne lead may result in multiple effects on reproductive behavior and overall
reproductive success in fathead minnows (Weber 1993). A recent review of wildlife
contamination in Chesapeake Bay cited older articles that found that lead adversely affected
embryo development and neurological behavior in the green and bull frogs (Heinz et al. 1992).
COMBUSTION EMISSIONS
As discussed in Chapter I, this pollutant group is comprised of 2,3,7,8-tetrachlorodibenzo-
p-dioxin (TCDD, dioxins), 2,3,7,8-tetrachlorodibenzofuran (TCDF, furans), and polycyclic organic
matter (POM). Polychlorinated biphenyls (PCBs) are also discussed under this pollutant group;
they were historically produced for use in electrical equipment and hydraulic fluids but are often
now released into the environment in combustion gas emissions when PCB-containing materials
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are incompletely burned. The potential ecological effects associated with these pollutants are
discussed below.
TCDD. As shown in Table II-8,
dioxins are associated with effects in fish,
birds, and mammals, including reproductive
effects and other noncancer effects. EPA's
assessment of ecological effects in aquatic life
and associated wildlife discusses the effects
of TCDD in detail (U.S. EPA 1993a). A brief
summary of some of the findings is
presented below; please refer to this
document for the primary references for
these studies.
4 Available laboratory toxicity
information indicates that aquatic
invertebrates, plants, and amphibians
may be substantially less sensitive to
TCDD than fish. The report
emphasized that the data are limited.
4 The data indicate that young fish may
be more sensitive to TCDD than older
fish. Fish fry were most sensitive to
effects from TCDD following
exposure of eggs before or shortly
after fertilization.
Ecological Effects of TCDD in Lake Trout
Population in Lake Ontario
Commercial over-fishing and sea lamprey
predation are thought to be the primary causes of
lake trout decline in Lake Ontario. However,
several findings suggest that TCDD toxicity could
have contributed to the reproductive failure of
stocked lake trout in Lake Ontario in the post-
1950s: (1) the strong association between the
occurrence of blue-sac disease (a stress
syndrome) in sac-fry from TCDD-exposed fish in
laboratory studies and from eggs collected from
Lake Ontario; (2) the historical record of lake trout
exposure to TCDD and related chemicals in Lake
Ontario; and (3) the consistency of predicted
toxicity with the field sampling record of no natural
reproduction until 1986. Attainment of a self-
sustaining population of lake trout in Lake Ontario
requires exposures to TCDD and related
chemicals below the level that causes significant
reproductive impairment, in addition to sea
lamprey control, maintenance of adequate
spawning beds and water quality, and introduction
of lake trout strains appropriate for Lake Ontario's
conditions and food web.
Source: U.S. EPA 1993a.
4 In mammals and birds, the primary effect of concern is reproductive impairment. In
addition, because of the bioaccumulation of TCDD in aquatic food webs, the species most
exposed to TCDD are those species whose diet consists mostly of fish.
One of the main issues of current interest is the mechanism of action of dioxins (i.e., how
they bring about the effects). The unusual potency of dioxins in eliciting toxic effects suggested
to researchers that a dioxin receptor existed. Based on a substantial amount of biological and
genetic evidence, an intracellular protein called the aryl hydrocarbon receptor (Ah receptor) is
believed to mediate biological responses to TCDD and related compounds. Figure II-2 presents a
simplified diagram of how biological responses to dioxin-like compounds are mediated by the
Ah receptor. Although our understanding of the Ah receptor is limited, mammals (including
humans), birds, and fish all have exhibited detectable concentrations of the Ah receptor in a
number of different tissues. In laboratory mammal studies, binding of dioxins to the Ah receptor
has been associated with weight loss, edema, liver damage, promotion of tumors, and adverse
effects on the immune and reproductive systems (Fox 1993). Researchers believe that responses
to TCDD are likely to vary within and between species, as well as between tissues in individual
species, based on differential responses to Ah-receptor binding. Several proteins are believed to
contribute to TCDD's gene regulatory effects; the response to TCDD probably involves a complex
relationship between multiple genetic and environmental factors.
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Recent studies of dioxins and furans
that were found through the literature
search conducted for this Report to
Congress demonstrated reproductive effects
(e.g., embryo anomalies, decreased hatching
success) in nesting wood ducks in an
Arkansas bayou (White and Hoffman 1995)
and potential neurotoxic effects in great
blue heron hatchlings, as indicated by
asymmetrical brain development (Henschel
et al. 1995).
PCBs. As shown in Table II-8, PCBs
are associated with adverse effects in plants,
invertebrates, fish, birds, and mammals.
These effects include reproductive/
developmental, metabolic/enzyme, and
neurological/behavioral effects. The specific
effects and the levels at which these effects
are seen may vary among the different PCB
congeners and mixtures. Recent articles on
the ecological effects of PCB exposure are
summarized below. These studies focused
on reproductive effects in invertebrates, fish,
birds, and mammals, immune effects in fish
and aquatic mammals, and other effects in
plants and fish.
FIGURE 11-2
Role of Ah Receptor in Biological
Responses to Dioxin Exposure
Dioxin Exposure
1
Free Dioxin in Tissues
1
Dioxin Binding to the
Ah Receptor in Cells
i
Ah Receptor-Dioxin Complex
Binding with DMA
i
Gene Regulation
i
m-RNA Regulation
i
Protein Synthesis
i
Biochemical Alterations
1 Interactions of
i Multiple Target
i Genes
Early Cellular Responses
(cell growth stimulation)
1
Late (irreversible) Tissue Response
(cancer, deformity)
Source: Adapted from EPA 1994c.
Reproductive and Developmental
Effects. A group of related studies investigated the reproductive effects of commercial
PCB and combinations of PCB congeners in mink. Two of these studies found that
commercial PCBs and combinations of PCB congeners adversely affected reproduction,
but that exposure to single PCB congeners did not produce these same effects (Backlin
and Bergman 1992; Kihlstrom et al. 1992). One of these studies showed a difference in
adverse reproductive effects (e.g., late fetal death versus early fetal death) between two
different commercial PCBs, Clophen A50 and Aroclor 1254 (Backlin and Bergman 1992).
In another study, PCBs were found to reduce egg production and total reproductive
capacity in a small crustacean species under laboratory conditions (DiPinto et al. 1993). A
study that investigated the developmental toxicity of PCB congeners in minnows
determined that several congeners caused severe teratogenic effects (e.g., inhibition of
yolk absorption) and early hatching (Silberhorn et al. 1992). Recent studies of Great
Lakes bird populations (e.g., common terns) provided further evidence of the
developmental problems linked to PCBs during the 1980s (Becker et al. 1993; Hoffman et
al. 1993; Yamashita et al. 1993). A literature review of wildlife contamination in
Chesapeake Bay cited historical evidence of elevated post-hatch mortality in the leopard
frog and in unspecified toad species related to PCB exposure (Heinz et al. 1992).
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4 Immune System Effects. In a recent study, production of antibodies was suppressed in
juvenile chinook salmon exposed to the commercial PCB mixture, Aroclor 1254 (Arkoosh
et al. 1994). In another study, delayed immune system responses in harbor seals fed
herring from the Baltic Sea were associated with PCB exposure (Ross et al. 1995). In a
study of dolphins, decreased immune system response was associated with elevated
levels of DDT and PCBs in their blood (Lahvis et al. 1995).
4 Other Noncancer Effects. Researchers have correlated detrimental effects on the quality
and quantity of growth, as well as increased mortality, in aquatic plants with
concentrations of PCBs (Doust et al. 1994). One study of winter flounder did not find a
strong association between exposure to PCBs and the development of particular liver
lesions (Johnson et al. 1993). Some recent studies have shown that effects from PCB
exposure may be amplified in the presence of other chemicals. For example, a study in
quail found that high levels of cadmium can amplify both the quantitative and qualitative
retention of PCB congeners in muscle tissue, especially some of the congeners that are
most toxic and resistant to metabolic degradation (Leonzio et al. 1992).
POM. The data in Table II-8 indicate that POM is associated with a range of adverse
effects to aquatic and terrestrial wildlife. Studies on the adverse ecological effects from exposure
to PAHs (a subset of POM) that have been completed in the last few years are summarized
below. These studies examined immune effects in fish and birds as well as various other effects
in algae, aquatic invertebrates, fish, and birds.
4 Immune System Effects. In a recent study, production of antibodies was suppressed in
juvenile chinook salmon exposed to PAHs (Arkoosh et al. 1994). Another study found
that PAH exposure suppressed the immune system in both adult and young starlings,
although only young starling showed overt signs of general toxicity (e.g., decreased body
weight and blood hemoglobin concentration) (Trust et al. 1994). A study of effects on fish
from PAH exposure found that macrophage activity, an important component of the
cellular immune system (i.e., protects the host by eliminating foreign material), was
markedly reduced (Huggett et al. 1992). The study results suggested that these effects
may be reversible.
4 Other Noncancer Effects. Recent research has investigated the increased toxicity of PAHs
following exposure of the pollutants to solar radiation. One study that investigated the
photo-induced toxicity of anthracene (a PAH compound) to a species of green algae
showed that the combination of ultraviolet (UV-A) radiation and anthracene produced
significant toxic effects. The study also concluded that algae may be slightly more
resistant to photo-induced toxicity than fishes and invertebrates (Gala and Giesy 1992).
Two recent studies on fish suggest a strong association between exposure to PAHs and
the development of internal lesions, commonly found in the liver and kidney, as well as
external lesions, such as lens cataracts (Huggett et al. 1992; Johnson et al. 1993). One of
these studies found a strong correlation between sediment PAH concentration and
stimulation of enzyme activity, which suggests that the PAHs are a main component of
the adverse effects observed in the fish (Huggett et al. 1992). In another study, dramatic
declines in PAH concentrations in sediment following the closure of a steel facility were
followed by a decreased incidence of liver cancer and liver lesions in brown bullhead
catfish (Baumann and Harshbarger 1995). A study of aquatic insect larvae from a
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CHAPTER II
ECOLOGICAL EFFECTS
contaminated area of the Niagara River found that higher body burdens of PAHs were
associated with menta ("teeth") deformities. The researchers determined that the
deformities were not passed on to future generations (i.e., that PAHs caused
malformations but did not permanently alter genes or chromosomes) (Dickman et al.
1992).
PESTICIDES
Information on the adverse effects of the pesticides of concern in the Great Waters
(chlordane, dieldrin, cc-HCH, DDT/DDE, HCB, lindane, and toxaphene) is summarized in Table
II-8. These data suggest that the pesticides of concern may produce a wide range of adverse
effects in terrestrial and aquatic wildlife of the Great Waters. Recent literature on the ecological
effects of pesticides was available mainly for DDT/DDE, HCB, and lindane; this information,
except for information on the potential for endocrine disrupting effects (which was discussed
earlier in this section), is summarized below.
DDT. Much of the recent literature on the ecological effects of DDT (and DDE) focuses
on reproductive impairment in birds. Other studies demonstrate effects to the immune systems
of mammals and impaired growth and survival of aquatic plants following DDT exposure.
4 Reproductive and Developmental Effects. Recent studies on natural bird colonies in the Great
Lakes indicate a decreased role of DDT/DDE in the reproductive success of these
populations (Weseloh et al. 1994; Weseloh and Ewins 1994; Bowerman et al. 1995). One
of these studies determined that for herring gull colonies in Lake Superior, eggshells
were only eight percent thinner than before the introduction of DDT (Weseloh et al.
1994). In this study, reproductive failure was attributed to causes other than toxic
contamination (e.g., predation and shortage of food supply). Similarly, another study
attributed increasing populations of double-crested cormorants in Lake Ontario to
reduced levels of contaminants (especially DDT/DDE) and increased availability of forage
fish (Weseloh and Ewins 1994). A study investigating the combined effects of DDE and
decreased food intake on reproduction in ringed turtle doves found that the lower the
percentage of normal food intake, the greater the effects of DDE exposure on breeding
success. DDE restricted breeding success apparently by limiting levels of hormones
necessary to develop and maintain active gonads, adequate courtship and brooding
behavior, and functional crop glands (Keith and Mitchell 1993). A study of freshwater
pond snails, which are an important component of invertebrate fauna in most eutrophic
and mesotrophic lakes, found that DDT exposure reduced their reproductive output
(Woin and Bronmark 1992).
4 Immune System Effects. In a study of dolphins, decreased immune system response was
associated with elevated levels of DDT and PCBs in their blood (Lahvis et al. 1995).
4 Other Noncancer Effects. In one study in aquatic plants, exposure to DDE caused mortality
and had detrimental effects on the quality and quantity of growth (Doust et al. 1994).
Hexachlorobenzene. Recent studies on ecological effects from HCB exposure
demonstrate reproductive and neurological effects in aquatic plants and animals. Impaired
growth and survival of aquatic species and liver damage in fish and birds have also been shown.
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4 Reproductive and Developmental Effects. Reproductive effects from HCB exposure
documented in recent literature include reduced reproduction in protozoa and fathead
minnows and reduced fertility in waterflea crustaceans (Constable and Orr 1994;
Government of Canada 1994).
4 Neurological/Behavioral Effects. In freshwater snails, exposure to HCB inhibited body
growth, altered metabolic activity, and stimulated egg production, which researchers
attributed to neurotoxic effects (Baturo et al. 1995). Kestrels, a small falcon species, have
shown ruffling of feathers and tremors following exposure to HCB (Government of
Canada 1994).
4 Other Noncancer Effects. In aquatic species, HCB was lethal to some marine invertebrates
and significantly reduced the survival rates of freshwater caddisfly larvae and fathead
minnows (Constable and Orr 1994; Government of Canada 1994; Schulz and Liess 1995).
In another study, exposure to HCB caused mortality and had detrimental effects on the
quality and quantity of growth in aquatic plants (Doust et al. 1994). One report
documented the following other effects in aquatic species related to HCB exposure:
reduced production of chlorophyll, dry matter, carbohydrate and nitrogen in some algae;
decreased growth of algae and protozoa; digestive gland damage in crayfish; and liver
necrosis in largemouth bass (Government of Canada 1994). In birds, HCB exposure
induced porphyria (a group of disorders related to altered metabolism of breakdown
products of hemoglobin known as porphyrins), increased liver weight, and slightly
damaged livers in Japanese quail and produced significant weight loss, increased liver
weight, and decreased heart rate in kestrels (Government of Canada 1994).
Lindane. Recent studies show effects in aquatic species following exposure to lindane,
including reproductive effects in aquatic invertebrates, immune effects in fish, and behavioral
effects in aquatic invertebrates.
4 Reproductive and Developmental Effects. One study documented reduced reproduction in
waterflea crustaceans from lindane exposure (Ferrando et al. 1995).
4 Immune System Effects. Laboratory experiments on rainbow trout found that antibody
production was significantly suppressed from lindane exposure at doses comparable to
those found in fish in polluted fresh waters, and that as the dose increased the more the
immune system was suppressed (Dunier and Siwicki 1994; Dunier et al. 1994).
4 Neurological/Behavioral Effects. As a result of brief exposures to high concentrations of
lindane, the mating behavior of freshwater crustaceans was disrupted (Malbouisson et al.
1994). In another study, the common mussel, Mytilus edulis, showed lower rates of
feeding-type behavior after exposure to lindane-contaminated sediments (Hermsen et al.
1994). Also, an annelid worm exposed to lindane in sea water exhibited delays in
settlement and metamorphosis; this species is otherwise known to be a colonizer of
disturbed or polluted areas (Hill and Nelson 1992).
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CHAPTER II
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4 Other Noncancer Effects. In two different studies, survival of a waterflea crustacean species
was inhibited by lindane exposure (Ferrando et al. 1995; Tidou et al. 1992); in one of these
studies, lindane also significantly repressed growth in the waterflea crustaceans
(Ferrando et al. 1995). In studies comparing data for several species of fish, acute toxicity
of lindane decreased with increasing total body fat in fish (Geyer et al. 1993,1994).
NITROGEN COMPOUNDS
The availability of biologically-usable nitrogen normally limits biological productivity in
coastal waters, but an over-abundance of nitrogen is a concern in areas where nutrient
enrichment problems, known as eutrophication, have developed. In addition to increasing
productivity, nutrient enrichment generally alters the normal ratios of nitrogen to phosphorus
and to other elements, such as silicon. This alteration may induce changes to phytoplankton
community structure. Species that normally occur in low abundance may be favored, and in
some cases, toxic and/or noxious algal blooms may result. On the New England coast, for
example, the number of red and brown tides and shellfish problems from nuisance and toxic
plankton blooms have increased over the past two decades. In coastal areas with poor or
stratified circulation patterns (e.g., Chesapeake Bay, Long Island Sound), the "overproduced"
algae tends to sink to the bottom and decay, using all (anoxia) or most (hypoxia) of the available
oxygen in the process, killing or driving away organisms that require oxygen. In addition, the
increase in suspended matter due to overproduction of algae decreases light penetration, causing
a loss of underwater seagrass and coral communities.
Atmospheric deposition of nitrogen compounds is recognized by all U.S. estuarine
programs on the east coast as either a significant contributor to estuarine eutrophication or a
mechanism of possible concern (ECARA 1996). An important consideration for controlling
atmospheric deposition of nitrogen is that the region from which the atmospheric nitrogen
pollution arises (i.e., the "airshed") is larger than the watershed that drains into the waterbody
and much larger than the water surface that is potentially affected. The extent of "airsheds" is
now starting to be recognized (e.g., see the discussion of the Chesapeake Bay airshed in Section
C of Chapter IV).
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CHAPTER II
HUMAN HEALTH EFFECTS
II.D Human Health Effects
This section is intended to provide a brief overview of the current literature on the
potential human health effects from exposure to the Great Waters pollutants of concern. In
general, the information presented in this section represents data published since the
background document from the First Report to Congress on exposure and effects (Swain et al.
1992a) was completed through 1995. Because the information presented in this report covers
only recent studies, it cannot be used alone to determine whether these effects are widespread in
the environment. As in the First Report to Congress, the contribution of atmospheric deposition
to toxic contamination and potential human health effects associated with exposure to the
pollutants cannot be quantified at this time.
Much of the information presented in this section on human health effects is based on
effects observed in animals, mainly in laboratory animal studies, that are suggestive of potential
human health effects. Unlike the effects of certain pollutants of concern on ecological health in
the Great Waters (discussed in Section II.C), data on adverse health effects observed in humans
from non-occupational exposure to the pollutants of concern are limited. This section focuses on
the effects of the pollutants of concern and does not attempt to summarize the exposure levels
responsible for the observed effects. In addition, this section does not attempt to distinguish
effects that may occur with long-term exposure to the pollutants of concern from those effects
caused by acute, high-level exposures (e.g., accidental spills). The potential effects of a pollutant
may vary with duration of exposure, possibly due to a breakdown of the chemical in the body to
another chemical that is more toxic or affects other target organs than the exposed chemical.
Conclusions from the First Report to Congress
Information from the First Report to Congress is presented here to provide a foundation
for the subsequent discussion of the recent information available for this report. The research
findings and studies presented in the First Report to Congress, as well as the background
document on exposure and effects (Swain et al. 1992a), led to the following conclusions
regarding the potential human health effects from exposure to the pollutants of concern:
Numerous studies indicated potential
human health effects associated with
the pollutants of concern (see
sidebar).
Though many of the pollutants of
concern are probable carcinogens, the
noncancer effects of these pollutants
are also a significant concern and may
be as detrimental as cancer, or more
so, to individuals and populations.
It is possible for low-level exposure to
several of the pollutants to have little ^^^^^^^^^^^^^^^^^^^^^^^^^
or no measurable effect on an adult,
yet alter the formation and function of critical physiological systems and organs in
Potential Human Health Effects
Caused by Pollutants of Concern
Cancer
Reproductive effects
Developmental effects, including effects on
embryos, fetuses, and children
Neurological (i.e., brain and nervous system)
effects
Immune system effects
Endocrine system effects, including effects on
hormone synthesis and function
Other noncancer effects, including liver and
kidney damage
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HUMAN HEALTH EFFECTS
children of the exposed adult, especially when the child is exposed at critical
developmental stages in the mother's womb.
4 Some human health effects caused by the pollutants of concern are subtle, result from
long-term exposures to low levels of pollutants, and may be delayed in onset and occur
across several generations. For example, long-term exposure to low levels of mercury
may result in kidney or nervous system damage only after gradual exposure and
bioaccumulation in the body.
The remainder of this section presents updated information on human health effects
associated with the Great Waters pollutants of concern.
Current Understanding of Human Health Effects
Since the First Report to Congress, updated information on the potential human health
effects from exposure to the pollutants of concern has become available. This section
summarizes the information first by discussing some notable research efforts relevant to the
potential human health effects of some Great Waters pollutants of concern, followed by a brief
overview of recent data on the potential human health effects for each pollutant of concern.
As discussed in Section II.C, the role
of endocrine disrupters in causing adverse
effects in wildlife and humans is an emerging
and controversial issue. Effects of endocrine
disrupters have been seen mostly in wildlife
and laboratory experiments; however, there
are a few known cases of accidental exposure
of humans to high concentrations of
endocrine disrupters (see sidebar for an
example). Humans are especially susceptible
to adverse effects when exposure to
endocrine disrupters occurs during periods
that are tightly controlled by hormonal
activity, such as during embryo and fetal
development (Bern 1992). As an example,
the chemical hormone diethylstilbestrol
(DBS) was given to millions of women to
prevent miscarriages between the 1940s and 1970s. Though the women were largely unaffected
by their exposure to DBS, their children exhibited adverse reproductive effects such as decreased
fertility in both sexes, testicular cancer in males, and abnormal pregnancies in females (Colborn
et al. 1993; Hileman 1994). Scientists use the DBS incident as a model of how endocrine
disrupters may affect humans.
Some researchers have cautioned that because of the complex interactions involved,
proving a cause and effect link between adverse effects in humans and endocrine disrupters will
be difficult. Some raise doubts about the severity of the effects of endocrine disrupters shown in
some of the scientific literature (Safe 1995). The investigators note that these chemicals are only
weak hormones; natural estrogens have been shown to be over a thousand times stronger than
Human Exposure to Endocrine Disruptors
Accidental exposure to cooking oil
contaminated with PCBs occurred in Japan in
1968 and Taiwan in 1979, affecting 3,000 to 5,000
people overall. Children born to women who
consumed the oil when pregnant exhibited birth
defects and developmental and behavioral
deficiencies that scientists believe may be related
to hormonal changes caused by exposure (Lai et
al. 1993; Rogan and Gladen 1992). Upon
reexamination of the Taiwanese children in the
early 1990s, researchers found that the children
scored lower than controls on IQ tests, girls were
shorter than average, and boys' peniseswere
significantly smaller than normal (Chen and Hsu
1994; Guoetal. 1993).
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estrogenic pesticides (Birnbaum 1994). In addition, some researchers theorize that the net effect
of natural and chemical endocrine disrupters may be zero, especially given that some
environmental estrogens are found in plants and have been shown to have beneficial effects,
such as inhibiting tumor formation (Safe 1995). The significance of endocrine-disrupting effects
in humans remains unclear.
Recent work on mixtures of endocrine disrupters raises possible answers to some of these
arguments. Researchers found that, in a simple yeast estrogen system, combinations of two
weak endocrine disrupters, such as dieldrin and toxaphene, were 10 to 1,600 times more potent
than individual compounds in eliciting binding and activation of the human estrogen receptor
(Arnold et al. 1996). This research is preliminary, but has important implications, especially
because pollutants in the environment are typically found in mixtures.
In addition to the recent focus on endocrine disrupters, other research efforts relevant to
the potential human health effects of the pollutants of concern include the following:
4 EPA submitted a draft Mercury Study Report to the Science Advisory Board (SAB) for
review in June 1996. The report was reviewed by SAB in February 1997. EPA expects to
receive the opinion of SAB in the summer of 1997. The final Mercury Study Report will
fulfill the requirements of CAA section 112(n)(l)(B), including a requirement to assess the
public health impacts of mercury emissions.
4 In response to growing scientific controversy regarding the potential effects from
exposure to dioxins and related compounds, EPA began a scientific reassessment of the
health risks from exposure to TCDD and chemically-related compounds (known
collectively as dioxins and including TCDFs) in April 1991. Activities under the dioxin
reassessment included updating and revising the health assessment and exposure
assessment documents and performing research to characterize ecological risks in aquatic
ecosystems. The dioxin reassessment document was published in draft form in June 1994
and is found in two reports (each 3 volumes): the health assessment document (U.S. EPA
1994c) and the exposure document (U.S. EPA 1994d). More detailed information on the
human health effects related to TCDDs and TCDFs are discussed later in this section.
Based on the above research areas of interest plus human health effects data from the
First Report to Congress and from recently published studies, Table II-9 presents the potential
human health effects associated with the Great Waters pollutants of concern, except nitrogen.
Nitrogen compounds are not included in this table because nitrogen compounds that are
atmospherically deposited generally are not a direct hazard to human health. (Nitrates in
drinking water from wells are of concern in many areas, but are not linked to atmospheric
deposition.) For balance in understanding the importance of nitrogen oxides and other nitrogen
emissions to the atmosphere, effects on human health due to ozone formation resulting from
nitrogen compounds are briefly discussed later in this section. The data in Table II-9 generally
are based on a compilation of results from laboratory studies on whole animals, toxicity/cellular
studies in "test tubes" (i.e., in vitro studies), and human epidemiological studies describing
occupational or accidental exposure to high concentrations of chemicals. Although these studies
identify serious potential effects for humans, it is difficult to determine the adverse effects that
would actually occur with chronic and low-level exposure to these pollutants in the
environment. Since the First Report to Congress, Table II-9 has been updated to recognize the
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TABLE 11-9
Potential Human Health Effects Associated With Pollutants of Concern'
Pollutant
Cadmium and
compounds
Chlordane
DDT/DDE
Dieldrin
Hexachloro-
benzene
oc-HCH
Lead and
compounds
Lindane
Mercury and
compounds
PCBs
Polycyclic
organic matter6
TCDF (furans)
TCDD (dioxins)
Toxaphene
Potential Effects on Human Health b
Cancer0
Probable
Probable
Probable
Probable
Probable
Probable
Probable
Probable'
Possible9
Probable
Probable
Not
classifiable
Probable'
Probable
Reproductive/
Developmental
•
•
•
•
•
•
•
•
•
•
•
•
•
Neurological/
Behavioral
•
•
•
•
•
•
•
•
•
•
•
Immunological
•
•
•
•
•
•
•
•
•
•
•
•
•
Endocrine
•
•
•
•
•
•
•
•
•
•
•
•
Other
Noncancerd
Respiratory and
kidney toxicity
Liver toxicity
Liver toxicity
Liver toxicity
Liver toxicity
Kidney and
liver toxicity
Kidney toxicity
Kidney and
liver toxicity
Kidney toxicity
Liver toxicity
Blood cell
toxicity
Liver toxicity
Chloracne
Cardiovascular
effects; liver
toxicity
a Sources: Barnea and Shurtz-Swirski 1992; Cassidy et al. 1994; Chowdhury et al. 1993; Clayton and Clayton 1994; Colborn et al. 1993;
Howard 1991; Under etal. 1992; Soto et al. 1993; ATSDR Toxicological Profiles (see list in References chapter); and U.S. EPA 1987a,
1987b, 1988, 1989, 1990, 1991 a, 1993d, and 1994c.
b For purposes of this table, a pollutant was considered to induce an effect if human or laboratory mammal data indicating a positive result
were available. Blanks mean that no data indicating a positive result were found in the references cited (not necessarily that the chemical
does not cause the effect).
0 Cancer classifications: (1) "probable human carcinogen" when there is limited or no evidence of human carcinogenicity from
epidemiological studies but sufficient evidence of carcinogenicity in animals (corresponds to EPA weight-of-evidence category B); (2)
"possible human carcinogen" when there is limited evidence of carcinogenicity in animals and inadequate or lack of human data
(corresponds to EPA weight-of-evidence category C); and (3) "not classifiable as to human carcinogenicity" when there is inadequate
human and animal evidence of carcinogenicity or when no data are available (corresponds to EPA weight-of-evidence category D). Data
on cancer classifications are obtained from EPA's Integrated Risk Information System (IRIS), unless otherwise noted.
d This column reports only a sample of other noncancer effects that may occur as a result of chronic exposure to the pollutant. Additional
adverse human health effects may be associated with each chemical.
e POM represents a class of numerous compounds; not every compound is responsible for the potential effects on human health.
f Data from Health Effects Assessment Summary Tables (HEAST), which classify these chemicals as probable human carcinogens;
however, these carcinogenic evaluations are currently under review by EPA.
9 Inorganic (mercuric chloride) and organic (methylmercury) forms are classified as "possible," whereas elemental is "not classifiable."
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potential endocrine-disrupting effects of DDT/DDE and lindane, and the "possible human
carcinogen" classification for mercury (organic and inorganic forms).
The current information on the human health effects associated with each of the
pollutant groups is highlighted in the remainder of the section.
MERCURY AND COMPOUNDS
Mercury, a metal, is discussed separately from other metals because of the significant
emphasis placed on mercury in section 112 of the CAA and the difference in its behavior and
effects compared to other metals. It has long been known that organic mercury (methylmercury)
bioaccumulates in fish, and can biomagnify in the food web. In the air, mercury exists primarily
as elemental (Hg°) and inorganic (Hg[II]) mercury. Most of the mercury in water, soil, or
sediments occur in the form of elemental mercury and inorganic mercury salts.
Humans are most likely exposed to mercury indirectly as methylmercury through a diet
containing contaminated fish, instead of directly from inhalation of mercury in air. Ingestion of
mercury-contaminated fish can result in various health effects, particularly toxicity to the
nervous system in adults and in children exposed as fetuses. As shown in Table II-9, mercury
may also affect the reproductive and immune systems. Since the First Report to Congress, EPA
has recommended the current rating of the scientific weight-of-evidence regarding the human
carcinogenicity of mercury (U.S. EPA 1993d):
• Elemental mercury: not classifiable as to human carcinogenicity;
• Inorganic (mercuric chloride) and organic (methylmercury) mercury: possible
human carcinogens.
In recent years, researchers, including EPA, have focused on several issues related to the
health effects of methylmercury: (1) improving the quantitative estimate of the relationship
between mercury levels in air and exposure levels; (2) using refined statistical approaches and
the application of physiologically-based pharmacokinetic models to evaluate the critical dose
levels at which health effects occur from mercury; and (3) effects on nervous system develop-
ment in populations that consume mercury-contaminated fish. New data are available from a
recently-published study investigating neurological effects in children belonging to a fish-
consuming population in the Seychelles Islands. Data from evaluation of these children (up to
six years of age) have been collected and are being analyzed. Data from a similar study in the
Faroe Islands have been published in abstract form; however, further investigation is being
conducted to determine if the study subjects also may have been exposed to PCBs. Smaller scale
studies evaluating effects in populations around the Great Lakes also are in progress. The above
data and methodologies have not yet been incorporated into an EPA risk assessment of methyl-
mercury because a majority of the new data are either not yet published or have not yet been
subjected to rigorous review.
OTHER METALS
Cadmium. As indicated in Table II-9, cadmium has been linked to numerous adverse
human health effects, including respiratory and kidney toxicity, probable carcinogenicity,
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reproductive and developmental effects, and immunological effects. Recent literature discussing
the adverse human health effects of exposure to cadmium is limited and generally is focused on
how cadmium alters the function of the kidney, which is known to be the critical organ for
cadmium exposures (WHO 1992). Cadmium exposure has been found to cause deficient vitamin
D metabolism in the kidney, which subsequently affects the calcium balance and bone density
and may result in osteoporosis or osteomalacia (both bone diseases characterized by a change in
the mineral and matrix phases of bone tissue). Exposure to cadmium has also been linked to
developmental effects (e.g., particularly low birth weight).
Lead. Recent literature on human
health effects from lead exposure generally
supports the findings presented in II-9: lead
is considered a probable carcinogen and may
affect reproduction and development, alter
the immune, nervous, and endocrine
systems, and damage the kidney. While the
correlation between high levels of lead in
blood and adverse human health effects is
relatively well known, current research has
focused on the adverse effects associated
with low levels of lead in blood (<30
micrograms of lead per deciliter of blood, or
jug/dL) (see sidebar). Low levels of lead may
be found in blood of a significant portion of
the general public (U.S. EPA 1991b). Effects
from low level exposure range from subtle
cellular changes, such as effects on red blood
cell metabolism, to pronounced effects on
physical and mental development (Hovinga
et al. 1993; Huseman et al. 1992; Kim et al.
1995). Blood lead levels as low as 10 jug/dL
(and possibly lower) may result in adverse
human health effects (Mushak et al. 1989;
U.S. EPA 1991b). EPA has also noted that
infants and young children may be most susceptible to adverse effects resulting from lead
exposures (U.S. EPA 1991b).
COMBUSTION EMISSIONS
TCDD and TCDF. As shown in Table 11-9, the potential human health effects from
exposure to TCDD include probable carcinogenicity, and reproductive and developmental,
neurological and behavioral, immunological, and endocrine system effects. For TCDF, the
potential human health effects are reproductive and developmental, immunological, and
endocrine system effects, and liver toxicity. The dioxin reassessment document (U.S. EPA 1994c)
discusses the effects of TCDD and related (compounds collectively referred to as dioxins) in
detail. A summary of some of the research presented in the reassessment is discussed below;
please refer to the reassessment document for the primary literature references for these studies.
Low-Level Lead Exposure
Because of the adverse human health effects
associated with low-level lead exposure coupled
with the numerous exposure pathways for lead,
EPA has abandoned its standard approach for
evaluating chemical toxicity in favor of a site-
specific modeling approach. In 1994, EPA
released a revised version of the Integrated
Exposure Uptake Biokinetic Model for Lead in
Children as its recommended methodology for
assessing lead exposure. The model considers
the principal lead exposure pathways (e.g.,
drinking water, diet, inhalation) to estimate lead
levels in blood of children. Overall lead intake is
then integrated in the model to estimate blood lead
concentration. This concentration can then be
used to predict: (1)the percentage of the exposed
population that will have blood lead levels greater
than 10 ug/dL; or (2) the probability that a child
exposed to this level will have a blood lead level
greater than 10 ug/dL EPA defines 10 ug/dL
blood lead as the lower bound of the range that is
known to cause adverse effects on behavior in
young children.
Source: U.S. EPA1994b.
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4 Carcinogenicity. A number of new studies provide further evidence that dioxins are
probable human carcinogens. Because available human studies alone cannot confirm
whether there is a causal relationship between dioxin exposure and increased cancer
incidence, assessors have extrapolated from available animal data to potential human
cancer. Recent animal studies have demonstrated dioxins to be carcinogenic in hamsters
and small fish. All of these data have contributed to the weight-of-evidence that dioxins
and related compounds may be carcinogenic, under certain circumstances, in humans.
4 Reproductive and Developmental Effects. The potential for dioxins and related compounds
to cause adverse reproductive and developmental effects in animals has been recognized
for many years. Recent laboratory studies have suggested that altered development may
be among the most sensitive TCDD endpoint in laboratory animals, although the
likelihood and level of response in humans is much less clear. One study of monkeys
found that chronic exposure to TCDD increased the risk of endometriosis, a female
reproductive system disorder that can be painful and produce infertility. Human
epidemiologic studies on the relationship between dioxin exposure and endometriosis
are planned as part of follow-up research to a 1976 dioxin release in Seveso, Italy.
4 Immune System Effects. Recent animal studies confirm that dioxins may cause
immunological effects and suggest that some effects may occur after low-level exposure.
There is conflicting evidence, however, concerning the effects of these compounds on
humans. A developing human immune system is believed to be particularly sensitive to
the effects of exposure to dioxins compared to adults, but additional research is necessary
to confirm this hypothesis.
4 Endocrine System Effects. Two human epidemiologic studies linked exposure to TCDD
with changes in male reproductive hormone levels. Two of three studies found
decreased testosterone levels and one of two studies observed an increase in a female
ovulation hormone in males. Animal studies have produced similar results.
4 Other Noncancer Effects. Chloracne is a severe acne-like disorder that develops within
humans after a few months of exposure to dioxin. It may disappear in some individuals
after exposure is discontinued, or persist in others for many years. Limited data exist to
determine the doses at which chloracne is likely to occur, but long lasting, high-intensity
exposures that begin at an early age are believed to increase an individual's chances of
contracting this skin disorder. Another potential effect is enzyme induction, which has
occurred in animals exposed to TCDD compounds. The biochemical alteration may
either benefit the animal or result in adverse effects to the animal (i.e., alter metabolism of
certain chemicals by increasing or decreasing toxicity). Studies linking this effect directly
to humans are not available.
Most dioxins are thought to affect animals and humans by binding with the Ah receptor.
The Ah receptor, which has been detected in humans, and its mechanism of action are discussed
in Section II.C.
PCBs. This section summarizes the potential human health effects that are generally
common to all PCB compounds, although the levels at which these effects may occur vary
between compounds. In addition, specific compounds may produce their own range of effects.
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As shown in Table 11-9, PCBs are classified as probable carcinogens, and potentially affect
reproductive, neurological, immunological, and endocrine processes in the human body. Recent
research suggests that PCBs may be able to act as endocrine disrupters in ways similar to many
pesticides and dioxins (McKinney and Waller 1994).
PCBs remain a significant concern because, although they have not been produced in this
country for over a decade, they are often released into the environment in combustion gas
emissions when PCB-containing materials are incompletely burned. In addition, appreciable
concentrations are still found in water, and animal and human tissue, milk, and blood. As
reported in Section II.A, the majority of fish advisories in the Great Waters are due to the
presence of PCBs.
One recent study comparing serum PCB levels in people who ate Great Lakes fish (i.e.,
consumers) to a control population found that serum PCB levels did not change substantially
over a seven-year period (Hovinga et al. 1992), as shown in Table 11-10. The study proposes a
number of reasons for the static PCB levels in the fish-consuming population: (1) restrictions on
PCB production alone may not ensure decreasing levels of PCB exposure in human populations;
(2) other sources of PCB contamination may be major sources of exposure; or (3) seven years may
not be a long enough time to see a decrease in body burdens of PCBs, due to the persistent
nature of these compounds, in human populations.
Changes in Serum PCB Levels in Great Lakes Populations
Hovinga et al. (1992) compared data from a 1982 study that examined 115 individuals who
consumed Great Lakes fish and 95 who did not eat fish (i.e., controls) to a similar study in 1989 that
reevaluated these individuals. Comparison of the data from the two studies (Table 11-10) shows a
significant decrease in mean serum DDT levels in both fish-eaters (almost 40 percent) and controls
(approximately 30 percent). In contrast, serum PCB levels decreased only slightly in fish-eaters and
remained relatively constant in controls. These results support other studies that have found stable PCB
levels over time when DDT levels have been decreasing and suggest that, despite their ban, restrictions
on PCBs have not been as effective in reducing levels of contamination in humans as those placed on
DDT.
TABLE 11-10
Mean Serum PCB and DDT Levels in Fish Eaters and Controls (1982 vs. 1989)a
Serum PCB (ppb)
Serum DDT (ppb)
Fish Eaters
1982
20.5
25.8
1989
19.0
15.6
Controls
1982
6.6
9.6
1989
6.8
6.8
3 Values represent 111 fish eaters and 90 controls (out of original 115 and 95,
respectively).
Potential sources of exposure to PCBs other than fish consumption are disposal of
previously manufactured products containing PCBs; atmospheric transport from other countries
where PCBs are still produced and used; and cycling of PCBs in the environment. The
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widespread use of PCBs in electrical equipment is of concern, but there has been an increased
awareness of the combustion of waste containing PCBs. The continued detection of PCB
concentrations in the environment suggests that there is a reservoir of PCBs from "old" pollution
that cycles between sediments, water, and air.
In view of this evidence of continuing
persistence of PCBs in the environment and
in the human population, effects on humans
related to this group of chemicals remain a
concern and many studies assessing their
effects are currently underway. A1992
workshop sponsored by EPA documented
several human health effects from exposure
to PCBs (see sidebar). Other recent findings
include:
4 Carcinogenicity. In response to
evidence that the development of
cancer may involve miscommun-
ication between cells, a recent study
investigated the effect of PCB expo-
sure on intercellular communication
in human breast cells and found that
cell communication was inhibited with
increasing doses (Kang et al. 1996).
Workshop on Developmental Neurotoxic
Effects Associated With PCB Exposure
In September 1992, EPA sponsored a
workshop on the developmental nervous system
effects of PCBs. At this meeting, experts
addressed whether currently available health
effects data are sufficient to support develop-
mental neurotoxicity data in risk assessment.
Some current findings regarding human health
effects associated with PCBs were discussed and
are summarized below.
• Women exposed to PCBs through
contaminated cooking oil experienced
irregularities in menstrual cycles, which may
suggest alteration in ovarian function.
• Potential nondevelopmental nervous system
effects include headaches, numbness, altered
peripheral nerve function, and decreased
neurobehavioral function measured through
visual memory and problem solving ability. In
animals, PCB exposure has been shown to
affect the actions of dopamine (a brain
neurotransmitter).
Reproductive and Developmental Effects.
In female rat pups given doses of
PCBs, one study observed delayed
puberty, fertility impairment, and
irregular estrus cycle patterns (Sager
and Girard 1994). The investigators
suggested that these reproductive
effects may be related to impairment
of endocrine function. One study
found that consumption of PCB-
contaminated sport fish from Lake
Ontario did not increase the risk for
spontaneous fetal death in humans,
which has been observed in various
mammalian species after PCB exposure (Mendola et al. 1995).
Neurological/Behavioral Effects. The effects of prenatal exposure to PCBs on neurological
function in children were investigated in a follow-up study of children from the
contaminated rice oil incident in Taiwan (introduced in the discussion of endocrine
disrupters earlier in this section). Researchers concluded that exposure of the fetus to
PCBs may impair the psychological functions of the brain in the child and that PCBs may
persist in the brain for a long period (Chen and Hsu 1994).
• PCB exposure has been associated with
atrophy of the thymus and immunosuppression
in animals (i.e., inhibition of immune cells
required for tumor resistance).
• Chloracne and liver dysfunction are associated
with occupational exposure to PCBs in humans.
In animal studies, increased mortality, skin
ailments, hepatotoxicity, and weight loss have
been demonstrated.
Source: U.S. EPA1993b.
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4 Other Noncancer Effects. Prenatal exposure to PCBs was associated with lowered
intellectual function in school-age children (Jacobsen and Jacobsen 1996). The most
highly exposed children were three times as likely to have low average IQ scores and
twice as likely to be at least two years behind in reading comprehension. Effects were
associated only with prenatal exposure, even though larger quantities of PCBs are
transferred by breast-feeding than across the placenta.
As discussed in the recently published health effects reassessment for dioxin, some PCBs
have been found to produce similar effects as dioxins.
POM. As shown in Table 11-9, adverse human health effects associated with POM
include reproductive and immunological effects, as well as probable carcinogenicity. Health
effects data on POM are available primarily for polycyclic aromatic hydrocarbons (PAHs), one
group of POM chemicals. Recent literature on health effects of PAHs corroborates previous
findings and investigates the mechanism of action for PAH effects.
4 Carcinogenicity. There is some speculation that ultraviolet light acts as a cofactor in the
development of PAH-associated skin cancer, although this hypothesis requires further
evaluation (Saboori and Newcombe 1992).
4 Reproductive and Developmental Effects. It has been demonstrated in human placenta samples
that short-term exposure to two PAHs (benzo[a]pyrene and 3-methylcholanthrene)
increases the secretion of human chorionic gonadotrophin (HCG) (an important hormone
in the human placenta) in the first trimester. This effect was maintained after application of
the PAHs was discontinued. The secretion of this hormone may be involved in adverse
reproductive effects observed with these pollutants (Barnea and Shurtz-Swirski 1992).
4 Immune System Effects. Exposure of experimental animals in the womb to PAHs was
found to alter development of the immune system and cause severe and sustained
postnatal immunosuppression (i.e., inhibition of immune cells necessary for tumor
resistance) (Holladay and Luster 1994).
PESTICIDES
The pesticides of concern for the Great Waters are chlordane, DDT/DDE, dieldrin,
hexachlorobenzene, cc-HCH, lindane, and toxaphene. As shown in Table 11-9, these pesticides are
probable human carcinogens and potentially result in toxic effects to reproductive, immune, and
endocrine systems, as well as other noncancer effects.
Much of the recent literature concerning adverse health effects from exposure to the
pesticides of concern in the Great Waters discusses their estrogenic and other hormonal effects
(see earlier discussion of endocrine disrupters), as well as mechanisms of action of these effects
(Chowdhury et al. 1993; Foster et al. 1992a, 1992b; Johnson et al. 1992; Juberg and Loch-Caruso
1992; McNutt and Harris 1993). Current research that has further explored the mechanisms of
action of the pesticides in producing their known effects, other than endocrine disruption, are
summarized below.
4 Carcinogenicity. In response to evidence that the development of cancer may involve
miscommunication between cells, a few recent studies have investigated the effects and
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mechanism of action of cancer-promoting chemicals, including dieldrin, DDT, lindane,
and toxaphene, on intercellular communication (Kang et al. 1996; Leibold and Schwarz
1993; Rivedal et al. 1994; Tateno et al. 1994). They have found that cell communication is
inhibited with increasing doses of these chemicals.
4 Reproductive and Developmental Effects. In addition to studies of reproductive effects
associated with endocrine disruption, recent studies discuss the effects and accumulation
of the pesticides in reproductive organs (e.g., ovary) (Bourque et al. 1994; Lindenau et al.
1994; Singh et al. 1992). One recent study concluded that DDT is not toxic to sperm
(Under et al. 1992).
4 Neurological/Behavioral Effects. Studies on the adverse effects from exposure to neurotoxic
pesticides provided further support of their adverse neurological effects, investigated the
mechanisms of action producing these effects, the specific regions of the central nervous
system affected (e.g., the motor primary cortex and hippocampus in the brain), and
whether there is a critical exposure period for these effects (Barren et al. 1993; Eriksson et
al. 1992,1993; Gilbert and Mack 1995; Goldey and Taylor 1992; Gopal et al. 1992;
Johannson et al. 1993; Kilburn and Thorton 1995; Nagata et al. 1994; Rivera et al. 1992).
Many of these studies evaluated nervous system effects during development in young
animals, and determined that progression of the effects, as well as severity of these
effects, is influenced by the time of exposure (e.g., formation of the nervous system is a
sensitive stage of development). Data also suggest that some effects of early exposure to
pesticides on certain regions of the central nervous system may be reversible.
4 Immune System Effects. Studies investigating the mechanisms of action for producing
immunological effects and the effects on specific organs in the immune system (e.g.,
spleen) have confirmed the potential adverse immunological effects related to these
pesticides. Immune system effects (e.g., suppression, autoimmunity) were observed in
humans with elevated levels of chlordane (McConnachie and Zahalsky 1992). Animal
data have demonstrated that immune system stimulation (i.e., increased antibodies)
and/or suppression (e.g., decreased production of certain antibody-forming cells) may
result with exposure to DDT, dieldrin, HCB, and lindane (Flipo et al. 1992; Meera et al.
1992; Rehana and Rao 1992; Saboori and Newcombe 1992; Saha and Banerjee 1993;
Schielen et al. 1993).
4 Other Noncancer Effects. A review of literature on human health effects from long-term
exposure to pesticides concluded that (1) chlordane may cause disorders in bone marrow;
(2) DDT can cause chloracne, chromosome aberrations, tremors, muscular weakness, and
high levels of cholesterol and triglyceride; and (3) hexachlorobenzene may cause
metabolic abnormalities and liver cancer (Maroni and Fait 1993). Another study
demonstrated that lindane may impair development of blood cells in the bone marrow
(Parent-Massin and Thouvenot 1993).
NITROGEN COMPOUNDS
Nitrogen in the molecular form N2 is the most abundant gas in the earth's atmosphere,
and is essentially chemically inert under ambient environmental conditions. Other compounds
of nitrogen, particularly oxides of nitrogen, are common in the air due to their formation mainly
through coal and oil fossil-fueled electric power generation and automobile fossil fuel
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combustion, and produce a variety of effects on human health and the environment. EPA has
several programs, in addition to the Great Waters program, that are evaluating and attempting to
reduce the threat to human health from atmospheric nitrogen dioxide, ozone, and acidic
precipitation or particulates (U.S. EPA 1995c, 1995d, and 1995e). These other programs also
examine general environmental effects of the nitrogen compounds, while the Great Waters
program concentrates on the effects from nutrient enrichment, or eutrophication, in waterbodies
from atmospheric deposition of nitrogen compounds (see Section II.C on ecological effects).
Oxides of nitrogen are produced abundantly by many modern combustion processes. Of
the oxides of nitrogen, nitrogen dioxide (NO^ is the most abundant in emission plumes or
vehicle exhaust. At times, NO2 itself can reach ambient concentrations associated with a variety
of acute and chronic health effects. A more common problem is that, in the presence of sunlight,
nitrogen oxides in the atmosphere react with volatile organic compounds (VOCs) to form ozone.
Although ozone in the stratosphere is essential for protecting the earth from harsh ultraviolet
rays, lower level ozone (or photochemical smog) contributes to a variety of health problems.
Additional problems are posed by fine particles in the atmosphere. Under certain conditions in
the air, oxides of nitrogen can undergo additional reactions resulting in fine particles or
contribute to acids in aerosol droplets. EPA has set health-based National Ambient Air Quality
Standards (NAAQS) for NO^ for ozone, and for fine particulates (which have many sources in
addition to nitrogen oxides). Acidic precipitation is also affected by nitrogen oxide emissions,
and is the focus of another EPA program. Recent publications from those programs and NAAQS
reviews should be consulted for details on the human health effects of nitrogen. The Great
Waters program evaluates the reductions in nitrogen compounds that these programs have
achieved and have proposed, and considers the net effects on waterbodies, but does not analyze
direct human health effects from inhalation.
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II.E Other Effects
In addition to adverse effects on human and ecological health, atmospheric deposition of
the pollutants of concern may contribute to other adverse effects including environmental justice
concerns (e.g., effects on subsistence fishermen), commercial and recreational fishing losses, and
other recreational losses. This section provides a very brief overview of these other potential
effects. This section does not attempt to establish a link between these effects and atmospheric
deposition of the pollutants of concern to the Great Waters.
Environmental Justice Concerns
As introduced in the First Report to Congress, an important environmental justice issue
in the Great Waters is whether certain groups of people may have higher exposures to the
pollutants of concern than the general population, and therefore potentially greater risks for
adverse health effects. One potential effect, cancer, is discussed in the box below (note that
noncancer effects may be as or more important).
Subpopulations with Higher Lifetime Cancer Risks
In developing the Great Lakes Water Quality Guidance (GLWQG), EPA estimated baseline human
health (cancer and noncancer) risks for certain subpopulations in each of the Great Lakes. Baseline health
risks were based on fish tissue concentrations of chlordane, DDT, dieldrin, hexachlorobenzene, mercury,
PCBs, 2,3,7,8-TCDD, and toxaphene. Table 11-11 presents the low and high estimated lifetime cancer risks,
as well as EPA's "acceptable" range of lifetime cancer risk for human health. As shown in the table, the risks
to the subpopulations are well above the accepted risk range.
TABLE 11-11
Lifetime Cancer Risks in Various Great Lakes Subpopulations Versus
EPA's Appropriate Range of Risk to Human Health3
Subpopulations
Native Americans (subsistence anglers)
Low income minority sport anglers
Other sport anglers
EPA's Acceptable Range of Lifetime Cancer Risk for
General Population11
Low
18 in 10,000
25 in 10,000
9.7 in 10,000
High
370 in 10,000
120 in 10,000
450 in 10,000
0.01 in 10, 000 to 1 in 10,000
a Cancer risks were driven by fish tissue PCS concentrations which were lowest in Lake Superior
and highest in Lake Michigan. Therefore, low end of range represents Lake Superior and high
end represents Lake Michigan.
b EPA's acceptable range of lifetime cancer risk is based on the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP) [40 CFR Part 300].
Sources: U.S. EPA 1995a, 1995h.
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Some populations are at higher risk because they may be more vulnerable to effects (e.g.,
children). Other populations may be more highly exposed because they consume larger
quantities of Great Waters fish than the general population (e.g., for subsistence reasons); these
populations include Native Americans, the urban poor, and sport anglers. For example,
researchers found a relationship between fish consumption levels and socioeconomic
characteristics in a study of Michigan licensed sport anglers. A combination of minority status
and relatively low annual income (less than $25,000) was correlated with higher levels of fish
consumption (West et al. 1993). Higher fish consumption rates have been correlated with higher
levels of contaminants in the blood:
4 High levels of dioxins and furans were found in frequent consumers of fish living near
the Baltic Sea in Sweden. Individuals with the highest percentage of fish in their diet,
specifically fishermen and fishing industry workers, had blood levels that were
approximately three times that of non-fish consumers (Svensson et al. 1991).
4 On the north shore of the Gulf of the St. Lawrence River, fishermen who consumed large
amounts of seafood had elevated levels of PCBs in the blood. The blood levels among the
highly exposed fisherman were 20 times higher than controls (Dewailly et al. 1994).
As indicated in Section II.A, fish consumption advisories are designed to take into
account the fact that some populations are potentially at a greater risk for exposure and potential
effects than the general population. Recent studies indicate that some high-risk populations are
changing their fish consumption and preparation habits in response to fish consumption
advisories. A survey of 8,000 sport anglers in the Great Lakes states found that 36 percent of the
respondents had changed their fish consumption behaviors, including modifying fish cleaning
and preparation methods and eating less Great Lakes fish (Connelly and Knuth 1993). Another
study found that pregnant women of the Mohawk nation had substantially reduced their fish
consumption (Fitzgerald et al. 1993).
While fish advisories are designed to the reduce the harmful health effects from eating
contaminated fish, they may have negative cultural, societal, and economic impacts. A few of
these factors are described briefly below (adapted from U.S. EPA 1996a):
4 Nutritional Value. Fish are known to be high in important nutrients such as protein and
are generally low in fat. By heeding advisories to limit or avoid fish consumption, people
may reduce their intake of an important food source without supplementing their diet
with other nutritional foods or vitamin supplements. This is especially true for poor
subsistence fishers; after fish consumption advisories are issued, these people may not be
able to afford other means for eating a well-balanced diet.
4 Health Benefits of Fish Consumption. A diet rich in fish may have some important health
benefits, as demonstrated by studies that have compared diets high in fish with
traditional western diets (summarized in U.S. EPA 1996a). Examples of possible health
benefits from diets with a high proportion of fish are reduced risk for cardiovascular
disease and certain cancers. Therefore, the health risks from not eating fish may
outweigh the potential health risks from eating contaminated fish.
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OTHER EFFECTS
4 Traditional Activities. Eating and catching fish are important cultural activities for many
subgroups. For example, for centuries some Native American tribes have built cultural
traditions around spearing fish and sharing the catch (U.S. EPA 1992). Tribes that live
near large waterbodies often use certain fish species to symbolize characteristics or ideas.
For sport anglers, fishing and eating their catch are important social activities. Issuing
fish advisories can impose on these important cultural activities, greatly affecting a
subgroups' traditional values.
4 Dietary Patterns. Subgroups such as Native American and Asian American communities
have long-standing traditions of eating fish and place importance on celebratory meals
highlighted by fish. People may not want to substitute different ingredients or cook in
different ways. In addition, the potential substitutes for fish may be more unhealthy and
expensive.
4 Fishing and Tourism Industries. As discussed below, fishing advisories may negatively
affect the fishing and tourism industries.
An on-going Canadian study established as a First Nations/Health Canada partnership is
assessing the extent of exposure of Native people living in the Great Lakes basin to bioaccumulative
pollutants and the associated risk to their health and well-being. The project, Effects on Aboriginals
from the Great Lakes Environment (EAGLE), began in September 1990 and is expected to be com-
pleted in 1997. EAGLE is a community-based epidemiological project involving the approximately
100,000 First Nations people living in 63 aboriginal communities in the Great Lakes Basin. The
project builds on earlier studies and is examining exposure in both adults and children, socio-
economic effects, and the impacts on traditional ways of life, culture, and values (Manno et al. 1995).
Commercial and Recreational Fishing Losses
Bans and advisories on commercial
fishing due to pollution can cause economic
and social losses to owners and employees of
commercial fishing enterprises. In addition,
bans and advisories on recreational fishing
have potentially far-reaching effects on the
U.S. economy; expenditures on recreational
fishing stimulate the economy, provide jobs
in the industry, and generate state and federal taxes (Fedler and Nickum 1992). In 1991, more
than 35.6 million Americans over 16 years of age spent a total of $24 billion on sport fishing,
averaging 13 trips each and 14 days a year (U.S. FWS 1993). As shown in the sidebar, losses due
to fish consumption advisories can be significant.
The Arkansas Game and Fish Commission
has estimated a loss of fishing expenditures due
to mercury fish consumption advisories of over $5
million dollars from 1991 to 1992.
Source: Armstrong 1994.
Other Recreational Losses
In addition to recreational fishing, recreational hunting (e.g., for food or fur) may be
negatively impacted by exposure of wildlife to the pollutants of concern. These impacts include
decreases in the populations of hunted species (e.g., stemming from adverse reproductive
effects) and increased health risks to the hunters who consume their kill. Poor water quality
(and/or public perception of poor water quality) may negatively affect recreational uses other
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than fishing and hunting, such as boating,
swimming, and visiting parks. Decreased
recreational use also may affect the related
tourism economies; the annual outdoor
recreation/wildlife industry in Great Lakes
states generates approximately $12 billion
(NWF 1993). An example of efforts to study
the impact of recreational losses in one of the
Great Waters is presented in the sidebar.
EPA is currently funding a project that will
assess the value of certain recreational services
(e.g., bird watching, windsurfing, fishing) to the
Corpus Christ! Bay National Estuary Program.
The objective of this project is to assist in
prioritizing management actions for this estuary.
Findings from the project will be used, in part, to
provide a framework for assessing both economic
and natural resource value losses due to negative
impacts associated with excess nitrogen loadings
to Corpus Christ! Bay and other estuaries.
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Section 112(m) of the Clean Air Act (CAA) directs EPA, in cooperation with the National
Oceanic and Atmospheric Administration (NOAA), to assess the extent of atmospheric
deposition of hazardous air pollutants to the Great Waters. As part of this assessment, EPA is
directed to, among other things, monitor atmospheric deposition of pollutants, investigate
pollutant sources and deposition rates, and conduct research to improve monitoring methods.
Accomplishing these tasks requires an understanding of the processes by which the pollutants of
concern are transported from their emission sources and deposited to the Great Waters.
Researchers use mathematical models of atmospheric transport and deposition of pollutants to
analyze the movement of pollutants in the environment, to develop relationships between
sources and receptors of pollutants, and to evaluate prospective control strategies.
This chapter introduces some basic concepts and scientific terms that are relevant to
atmospheric transport and deposition of pollutants, and that are used throughout this report. It
also discusses general types of transport and deposition models, focusing on modeling
achievements of the most recent years and on efforts by EPA and NOAA plus other researchers,
mostly in academia. Further discussion of the uses of a few of these models is included in
Chapter IV.
There is currently a general understanding of the major factors that affect the transport of
air pollutants between their sources and receptors, as well as how these factors interrelate. The
development of new models and refinement of existing ones have been advanced in recent
years, as shown in this chapter. Research on the characterization of sources, processes, and
parameters has continued in parallel with monitoring efforts. The Great Waters have been and
will continue to be the focus of many of the investigations presented in this chapter.
Despite recent advances in our understanding of transport and deposition of
contaminants in the atmosphere, there is still a paucity of data with which to calibrate models
(measurement of dry deposition and source inventories are typical examples). Further analysis is
also required for some transport and deposition phenomena, such as the importance of
environmental cycling of contaminants emitted and deposited in the past.
This chapter is divided into three sections. Section III.A discusses some key terms, such
as deposition and environmental cycling. Section III.B presents a brief description of general
types of transport and deposition models. Section III.C compares some models that have been
recently used in Great Waters studies, and discusses modeling and data limitations.
III.A Atmospheric Deposition and Environmental Cycling
Long-range atmospheric transport and deposition of pollutants have been widely
acknowledged to make a significant contribution to contaminant inputs to surface waters,
including the Great Waters. Atmospheric deposition refers to the removal of pollutants
(following transport) from the air to soil, water, and other surfaces. Deposition may occur
directly to the water surface and/or indirectly to the land surface in the watershed, with
subsequent runoff from rainfall carrying contaminants to the waterbody. It is important to
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recognize that both local and distant air emission sources may contribute to the pollutant loading
at a given location and time. Also, pollutants may be emitted from a combination of point,
mobile, or area sources; or even from resuspension in the air of previously deposited material.
There are three major processes of direct atmospheric deposition to natural waterbodies:
wet deposition, dry deposition, and gas exchange across the air-water interface. A schematic of
these processes is presented in Figure III-l. In addition to these processes, cycling of semi-
volatile compounds (e.g., polychlorinated biphenyls (PCBs)) and persistent compounds among
environmental media (e.g., air, water, sediment) can be an important input of pollutants in
waterbodies.
FIGURE 111-1
Atmospheric Deposition Processes
Atmospheric Transport
Releases from Natural
and Anthropogenic Sources
Indirect
Deposition
Air/Water
Gas Exchange
Wet Deposition Dry Deposition
Re-suspension
Direct Deposition
River Outflow
River Inflow
Groundwater
Exchange
Monitoring and assessment of these processes provide important information on the
atmospheric contribution of a given pollutant to a specific site, as well as extent of deposition of
the pollutant. Hence, monitoring at Great Waters study sites requires meteorological
measurements and measures of contaminant concentrations very near to the site and, if possible,
over the surface of the waterbody itself. Understanding of these processes allows researchers to
evaluate quantitatively the long-term distribution of a pollutant in an aquatic system. EPA
sponsors research on atmospheric deposition so that future monitoring can become less research-
oriented and more focused on evaluating trends in atmospheric loading of pollutants and
determining the effects resulting from efforts to reduce emissions.
Wet Deposition
Wet deposition (or in more general terms, removal via precipitation) refers to the
incorporation of both gases and particles into cloud droplets and into "hydrometeors" (e.g., snow,
sleet, and rain) where they are carried to the Earth's surface in precipitation. Pollutants may be
removed from air by wet deposition through three main mechanisms:
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(1) minute pollutant-bearing particles can serve as cloud condensation nuclei and become
naturally embedded into water droplets during cloud formation; (2) particles may be
incorporated into falling hydrometeors by collisions; or (3) gaseous pollutants may be dissolved
into cloud droplets and falling rain. Cloud and precipitation droplets, therefore, may contain
pollutants in both particulate and dissolved forms. The removal of gases by wet deposition is
dependent on their solubilities in the elements of precipitation. Wet deposition is essentially an
intermittent process, although if precipitation events are frequent or long-lasting, wet deposition
may be the major pathway for deposition of air pollutants, specifically for totally particulate
species (e.g., metals other than mercury). For semi-volatile compounds, air-water gas exchange
appears to be a dominant factor (Hoff et al. 1996).
To get useful and quantitative measurements of wet deposition, well-prepared protocols
and quality assurance approaches are designed and used, with careful handling of field
equipment, samples, and subsequent chemical analyses. For example, wet deposition rates are
determined using collectors that are designed to open only during precipitation events. Work
must be designed and carried out so as to minimize measurement problems with the samples
that can arise from chemical or biological activity, evaporation of gaseous pollutants, or possible
contamination during storage and handling. The concentrations of most of the pollutants of
concern in any one precipitation event may be small, so rather advanced field and chemical-
analytical methods are needed for quantitatively assessing the concentrations. Though
measurements must be taken of short-term events in which the concentrations may be small, it is
important to track the concentrations of the pollutants of concern deposited over time because of
their persistence and tendency to bioaccumulate. Thus, the kind of monitoring used in the Great
Waters program involves research into new and more accurate monitoring techniques and must
be carefully designed to focus efforts on well-located sites, protocols, and methods.
Dry Deposition
Dry deposition refers to removal
from the air of pollutants (bound to
particles or in the gaseous form) to the
land or water surface in the absence of
precipitation. Dry deposition is
essentially a continuous process and often
represents a substantial removal of the
pollutants from the atmosphere. The
pollutants reach the surface by the
turbulent movements of the air or, for
large particles, through gravitational
settling. Dry deposition of particulates
with high deposition velocities is an
important contribution to pollutant
loadings to waterbodies located near
cities. For large open waterbodies, air-water gas exchange appears to contribute more than dry
particle deposition (Hoff et al. 1996). A review of models of dry deposition to water is presented
by Zufall and Davidson (1997).
Research on Dry Deposition
In 1994, a research program was established
among the EPA, the University of Michigan, the Illinois
Institute of Technology, Carnegie-Mellon University,
and Oak Ridge National Laboratory to develop and test
new techniques for measuring dry deposition of
mercury and other trace elements to natural water
surfaces. The data will be used to develop new
mathematical models for predicting dry deposition onto
water surfaces under a variety of atmospheric and
surface conditions. Measurement methodologies have
been developed and tested, and modeling is underway.
Field studies in 1996-1997 are planned to gather basic
data, and to compare with model predictions.
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Dry deposition is measured from pollutant accumulation on artificial surfaces (e.g., a
plexiglass plate). Alternatively, atmospheric pollutant concentrations and their mass-size
distribution can be combined with micrometeorology data to model dry deposition rates. The
major difficulty in measuring dry deposition is that there is no method that can be routinely used
because the flux density is so low and because the exchange rate is usually governed by details of
the surface that cannot be reproduced in artificial devices. The difficulties of measuring dry
deposition have motivated new research on measurement methodologies and modeling of dry
deposition under the Great Waters program (see sidebar on the previous page).
Gas Exchange Across the Air-Water Interface
In addition to wet and dry deposition of pollutants, gaseous pollutants may be directly
exchanged between air and water (i.e., transferred in either direction across the air-water
interface). The gaseous exchange of organic compounds at the air-water interface is an
important phenomenon in the balance of pollutants occurring in air and water (Eisenreich et al.
1997), and extensive North American waterbodies, such as the Great Lakes and Chesapeake Bay,
provide large surface areas for this exchange to occur. Analogous gas exchange phenomena
occur between plants and air, and land and air.
Gas exchange is a two-way process involving both gas absorption or invasion (air to
water) and volatilization or evasion (water to air) across an air-water interface of a volatile
chemical (usually in gaseous form under every-day conditions) or a semi-volatile chemical (e.g.,
polycyclic aromatic hydrocarbons (PAHs), PCBs). The direction of gas movement (from air to
water or from water to air) depends on the fugacity difference (i.e., the relation of the Henry's
law scaled air concentration to the water concentration). The direction of gas exchange will tend
to reduce this difference and move toward a near-equilibrium condition. The direction and
magnitude of gas transfer is a function of the chemical concentrations in air and water, wind
speed, temperatures in air and water, waves (height, frequency), physical and chemical
properties of the pollutant (e.g., molecular weight, vapor pressure, Henry's Law constant,
solubility), and in some cases characteristics of the water (e.g., pH for acidic and basic species,
and salinity in estuaries).
Gas absorption and volatilization occur simultaneously, even when near-equilibrium has
been achieved. Taken together, volatilization and gas absorption contribute to the net flux (the
difference between the amount of pollutant invading and the amount evading) or effective
movement of a chemical across the air-water interface. Net flux may be expressed as the mass of
gas moving across a unit of area over a unit of time (e.g., 8 ng per m2 of water surface per day).
To achieve quantitative estimates for the Great Waters of net deposition of pollutants of concern,
many of which are semi-volatile, such physical and chemical processes must be quantified so
they may be correctly used in models. Some earlier work on pollutant loading made simplifying
assumptions of "one-way" flux or deposition without quantifying gas exchanges, but recent work
shows the need for more complete representation of the natural processes for each pollutant.
Furthermore, it is important in some cases to determine both absorption and volatilization,
instead of net flux alone. Even under conditions close to air-water equilibrium, with small net
flux, the absorption and volatilization may be quite large, making gas exchange a key factor in
the analysis of pollutant movements (see Table IV-2 in Section IV.A on the Great Lakes).
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There are two models commonly used to describe gas exchange at the air-water interface.
The Stagnant Two-film Model (Liss and Slater 1974; Whitman 1923) is used to estimate gas
exchange at low wind speeds, which results in an essentially stagnant boundary layer just above
the water. However, as higher wind speeds generate more turbulence in the boundary layers of
both air and water, turbulent eddies bring small parcels of water to the surface, where they begin
to equilibrate with the atmosphere, and more rapid gas exchange of chemicals occurs. To
characterize this situation, the Surface Renewal Model may be used, but the choice of model for a
given situation is not always clear-cut. The air-water gas exchange models continue to be
improved to incorporate new factors such as effect of bubbles, breaking waves, and surface films.
For a review of these models, readers should refer to Theofannous (1984) and Eisenreich et al.
(1997).
Environmental Cycling of Semi-Volatile Compounds
The exchange and cycling of gases between air, water, and soil is especially important for
the pollutants of concern that are characterized by chemists as "semi-volatile" in nature. These
semi-volatile pollutants coexist in the atmosphere in both the gas and particle phases, and can
revolatilize into the air after deposition (though not as readily as volatile compounds such as
benzene or vinyl chloride). Semi-volatile organic compounds include PAHs, PCBs, and several
pesticides (e.g., hexachlorobenzene, cc-HCH, and lindane), as well as the metallic form of
mercury and many of the other 188 toxic pollutants listed as hazardous air pollutant (HAPs) in
section 112(b) of the CAA. Because these compounds possess very low vapor pressures and
water solubilities, they are distributed between the gaseous and particulate phase both in the
atmosphere and in the water column, and their distribution among air, water, soil, and
vegetation is very complex. This makes tracking or modeling movements of semi-volatile
compounds very difficult. Each pollutant has particular chemical-physical attributes affecting
phase distribution, so quantitative assessment requires that each pollutant be well understood.
Some of the pollutants of concern can be chemically persistent, maintaining chemical identity
(not being broken down) as they move among physical phases and, in many cases, into biological
tissues. Some other pollutants (such as PAHs) may change to compounds that are
bioaccumulative and more toxic than the parent compounds. Other groups of compounds may
separate into individual components due to interactions and relative movement among solids
and liquids in the environment (Wania and Mackay 1993).
Once released to the environment, persistent semi-volatile compounds may repeatedly
cycle between the atmosphere, land, and waterbodies. This cycle can extend over long time
periods, resulting in transport of the compounds for long distances. Long-distance transport
with repeated deposition to land or water and then revolatilization to the atmosphere has been
shown to occur in response to seasonal temperature changes, among other factors (Wania and
Mackay 1996). Other factors that influence the extent and duration of this cycling include
volatility and persistence of the substance; molecular weight; concentrations and temperatures in
air, soil, and water; and atmospheric circulation, pressure, and weather conditions. As the
seasons change, the behaviors of atmospheric contaminants change relative to their location in
physical media; therefore, sampling work and modeling calculations must be adjusted, for each
compound, to correctly estimate their presence and impacts. Warmer conditions on seasonal
and global scales generally favor net movement into the atmosphere. Often redeposition takes
place in areas of colder atmospheric temperatures (Wallace et al. 1996; Wania and Mackay 1993,
1996). The modeling of chemical fate and concentrations of semi-volatile pollutants over very
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large areas is challenging, and lack of data on pollutant source and release makes the validation
of existing models difficult (Wania and Mackay 1996). Also, the lack of definitive methods to
measure the concentration of the mix of gases, particles, and liquid droplets that constitutes some
of the organic semi-volatile pollutants being deposited poses significant challenges for validation
of models.
III.B Atmospheric Transport and Deposition Models
The emission, transport, transformation, and deposition of pollutants to the Great Waters
is a complex series of processes involving different pollutants that have different behaviors in air
and water systems, over very large geographic areas. Therefore, numerous models, as well as
input parameters for these models, have been and continue to be developed or evaluated for
estimating the atmospheric transport and deposition processes for the various pollutants
associated with the Great Waters.
Atmospheric transport and deposition models are used to:
• Predict the direction and distances pollutants will travel in the environment;
• Test hypotheses about characterizations of atmospheric transformations and
removal;
• Assist in designing monitoring networks for efficiency and specific analyses, and
in placing a limited number of monitors effectively;
• Provide calculated estimates to fill spatial and temporal gaps in monitoring
networks, to provide a smooth or coherent picture for analyses;
• Develop relationships between sources and receptors of pollutants; and
• Evaluate prospective pollutant control strategies.
This section discusses different types of models related to atmospheric transport and
deposition processes. Results from application of some models presented in this section are
described in Chapter IV. The models presented in this section can be classified in three
categories: mass balance models, source apportionment techniques, and air quality simulation
models.
Mass balance models analyze all ways that pollutants can enter and exit a waterbody,
and their corresponding amounts over a period of time (commonly referred to as the pollutant
loading). In other words, mass balance models consider the mass (or weight) of a pollutant that
is exchanged across interfaces between air, water, land, and sediments as inputs and outputs, to
assess the relative loadings of a pollutant into a waterbody by different pathways.
Source apportionment techniques attempt to link sources and receptors of pollutants of
interest. Primary source apportionment techniques include dispersion models, receptor models, and
hybrid models. Dispersion models trace pollutants from their sources to the air at given locations
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(e.g., a waterbody). Receptor models trace
pollutants in the air at a given location back
to particular source types. Hybrid models are
similar to receptor models, but also
incorporate meteorological data, and work
from both the source end and the receptor
end of the pollutant transport analysis. One
important uncertainty related to source
apportionment techniques is the lack of
complete and reliable input data, such as the
composition and emissions of some pollutant
sources. In addition, source apportionment
techniques cannot be applied well for air
pollutants that are widespread in the
environment, travel over long distances,
and/or are emitted in large quantities from
natural sources or broad area sources. A review
compounds, with special emphasis on the Great
Mass Balance Models. Estimate inputs and
outputs of a pollutant to a waterbody (i.e., total
amounts of a given pollutant that enter and exit a
water body by each of the various pathways).
Source Apportionment Techniques. Estimate
the relative contribution of different sources to air
pollutant levels at a specific receptor site (e.g., a
particular air mass over Lake Michigan on a
particular day).
Air Quality Simulation Models. Use extensive
source emission inventories, meteorological data,
and algorithms to simulate processes such as
dispersion of pollutants in the atmosphere,
transformation of compounds, and deposition.
of source apportionment techniques for organic
Waters, is presented by Keeler et al. (1993).
Air Quality Simulation Models (AQSMs) are used to characterize both the transport and
deposition of pollutants. As input data, these models use extensive source emission inventories
and meteorological data. AQSMs include algorithms to simulate processes such as dispersion of
pollutants in the atmosphere, transformation of compounds, and deposition. The models' results
typically include air concentrations and deposition rates of pollutants over a given area for a
specified period of time. Although comprehensive, AQSMs are limited by the quality of input
data, the computational difficulties of their algorithms, and the modeling of some processes (e.g.,
air-surface exchange).
The remainder of this section presents additional information on specific applications of
the model types mentioned above, especially those that have been recently applied to Great
Waters studies. The following subsections focus on mass balance models, receptor models, and
AQSMs.
Mass Balance Models
A mass balance model provides the essential framework for determining the relative
contribution of pollutant loadings from various mechanisms of input (e.g., direct discharge, river
input, atmospheric deposition) and output (e.g., sedimentation, volatilization, outflow) to and
from a waterbody. Mass balance models are also helpful to relate concentration measurements
to pollutant mass fluxes between different media (air, waterbodies, land surface) and to mass of a
contaminant in different environmental "pools" (e.g., a waterbody, a land region). As introduced
in the First Report to Congress, when reliable information is available for contributions from the
various sources, mass balance models may be used to estimate the importance of atmospheric
deposition (or any other mechanism) in causing contamination of a waterbody. Mass balance
models usually are good at recognizing sizable pollutant sources and receptors, but often lack the
resolution needed to deal with multiple smaller sources that by themselves are not significant,
but added together could be important in some situations.
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Mass balance studies have provided insights on atmospheric deposition issues relevant to
the Great Waters. A review of studies on relative atmospheric loadings of toxic contaminants
and nitrogen to the Great Waters is presented by Baker et al. (1993). These studies have provided
quantitative estimates indicating that: (1) atmospheric deposition can be the main contributor of
toxic chemical contamination and nitrogen enrichment to the Great Waters, although
uncertainties still exist; (2) the importance of atmospheric load for a specific pollutant in a given
waterbody depends on characteristics of the waterbody, chemical properties, and source
locations; and (3) chemicals may cycle between soil, air, water, and biota for many years.
The First Report to Congress presented mass balance case studies for some Great Waters
pollutants of concern, such as PCBs in Lake Superior, mercury in lakes in Wisconsin, and
nitrogen in the coastal waters of several Atlantic states. Considerable research continues on the
development and use of mass balance models for the pollutants of concern in the Great Waters.
The Lake Michigan Mass Balance Study, an EPA-sponsored research project, is responsible for a
comprehensive sampling effort in Lake Michigan, including measurements of pollutants such as
PCBs, trans-nonachlor (a component of technical grade chlordane), mercury, and atrazine in the
atmosphere, tributaries, open lake water, sediments, and food chain (fish tissue). Samples
collected over a two-year period (1994-1995) for modeling will be used to improve understanding
of key environmental processes that govern cycling and bioavailability of contaminants within
the Lake Michigan ecosystem. The approach modifies the classic mass balance within a closed
system to consider inputs from transport, including long-range transport. Analysis of some
selected modeling runs is expected in 1998. A more detailed discussion of this mass balance
project is described in Section IV.A.
Receptor Models
Receptor models, which are one type
of source apportionment technique, trace
pollutants in the air at various locations (such
as over a waterbody) back to particular source
types in order to estimate the contribution to
pollutant levels from a group of sources with
similar emissions. This type of model does
not use the detailed meteorological data or
extensive emission inventories used in air
quality simulation models. Receptor models
assume that chemicals of concern are affected
in the same way by all of the processes
involved in pollutant transport and
dispersion. This is a particularly useful
assumption, but it presents some difficulties
when clouds are present, when precipitation
occurs, or when extensive chemical
transformations of a pollutant are known to
occur. A limitation of the receptor models is
the lack of adequate "source profile" data,
which allow air pollution to be linked to a
particular source type. Source profiles refer to
Receptor Model for Great Waters
A project on atmospheric deposition in the
Great Waters, entitled Atmospheric Exchange
Over Lakes and Oceans (AEOLOS), was started in
1993 by EPA and scientists from the Universities
of Minnesota, Michigan, Maryland, Delaware, and
the Illinois Institute of Technology. The objectives
of this 4-year research program are to determine:
(1) the dry depositional fluxes of critical urban
contaminants to northern Chesapeake Bay off
Baltimore and southern Lake Michigan off Chicago;
(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. The contaminants being studied include
mercury, trace metals, PAHs, and PCBs.
Techniques involve using all three modeling
approaches described below - CMS, PCA, and
trajectory analyses. Research is expected to be
published in 1998.
'signatures" or "fingerprints" of emissions from a
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type or category of sources; these profiles are determined through samples taken from the actual
emissions (i.e., from the "smokestacks") followed by analyses comparing the chemical signature
to those of other categories of sources. Despite the limitations of receptor models, these models
provide useful insights into contaminant transport to the Great Waters (see sidebar on the
previous page).
Some receptor model types include:
4 Chemical mass balance (CMB): The CMB model assumes that emission characteristics (i.e.,
chemical and elemental composition, physical size, morphology) of various source types
are sufficiently different from one another that their contributions to a receptor may be
identified by measuring the characteristics in samples collected at the site. The observed
concentration pattern of an ambient sample at the receptor site is equated to a linear
combination of the appropriate pollutant source patterns, each weighted by an unknown
source strength term. The primary application of the CMB model has been to urban areas
such as Chicago and Baltimore. CMB models assume composition of all contributing
sources are known, and when this is not the case the uses of the model are limited.
4 Principal component analysis (PCA): The objective of PCA is to use mathematical analyses
to find a minimum number of factors, or source categories, that explain most of the
variance in a set of measurements from a receptor site, instead of using all sources as in
the CMB models. The number of statistically significant factors is usually found to be six
or less. PCA is often limited because it lacks fine resolution of contribution from various
distant sources. An advantage of PCA is that ancillary measurements (e.g., wind speed,
wind direction, relative humidity) may be incorporated into the analysis along with
pollutant concentrations.
Trajectory clustering: In these models,
a back trajectory is computed using
wind data, and the spatial probability
of an air "parcel" reaching a particular
receptor site at a particular time is
calculated. Under different
meteorological conditions, all
potential trajectories and concurrent
pollutant measurements are grouped
into a more manageable set of source
clusters and regions. A variant of this
approach is being used to assess
mercury deposition in the Great Lakes
basin (see sidebar).
Air Quality Simulation Models
Air quality simulation models (AQSMs) are used to characterize the emission, transport,
and deposition of hazardous air pollutants over large geographic areas. These models
incorporate fairly extensive source emission inventories and meteorological data bases (e.g.,
wind fields, temperature, mixing height), and apply the collected data to simulated processes
Trajectory Clustering Technique
in the Great Lakes
To determine the sources of mercury
deposition to the Great Lakes Basin, a regional
network of 10 monitoring sites was established in
1993 by EPA and the University of Michigan to
measure atmospheric mercury over several years.
The sampling will continue into 1997. Data will be
analyzed, using an improved trajectory clustering
technique, to determine the sources and source
areas most responsible for mercury deposition to
the Great Lakes.
Source: Burke and Keeler 1995.
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such as dispersion, transformation, and deposition. The models are run to generate estimates of
pollutant concentrations and deposition rates over a spatial and temporal pattern. AQSMs are
based on two approaches. In one approach, characteristics or properties of air are assigned to
fixed points in space at a given time. The second approach is based on a two- or three-
dimensional grid system for the geographical pattern of interest, and all the fundamental
processes (e.g., emissions, chemical and physical transformations, deposition) of discrete air
parcels are considered to occur within the individual grids or boxes.
The mathematical relationships between emissions and concentration (or deposition) are
typically nonlinear, due to the influences of atmospheric transport, chemical and physical
transformation, and deposition processes. AQSMs attempt to model the nonlinear physical and
chemical processes influencing atmospheric concentrations and deposition. AQSMs may be
useful tools in providing the analytical framework required to predict the environmental impacts
of proposed emission control programs and, consequently, performing both scientific and
regulatory assessments.
This section describes two of the
various AQSMs that have been developed
and peer-reviewed in recent years, the
Regional Lagrangian Model of Air
Pollution (RELMAP) and the Regional
Acid Deposition Model (RADM). These
two models (among others presented in
Section III.C) have been used in Great
Waters studies, and their results are
presented in Chapter IV. Another model
being developed for application to
atmospheric deposition in the Great
Waters is discussed in the sidebar.
RELMAP is used to simulate the
emission, transport, and diffusion of
pollutants, their chemical
transformations, and wet and dry
deposition. The model was originally
designed for sulfur analysis (the User's
Guide is presented in Eder et al. (1986)). It
has also been applied to mercury and other toxic metals (Bullock et al. 1997; Clark et al. 1992),
among others. For example, the goal of one study was to determine the extent of mercury
emissions to air in the United States over an entire year, the deposition to U.S. soil and
waterbodies, and the contribution by source category to the total amount of mercury emitted
and deposited within the United States (Bullock et al. 1997). Section III.C presents relevant
applications and limitations of this model.
RADM has been developed over the last ten years under the National Acid Precipitation
Assessment Program (NAPAP) to address policy and technical issues associated with acidic
deposition (Chang et al. 1990; Dennis et al. 1990). The version of RADM used for NAPAP models
an area east of Central Texas and south of James Bay, Canada, to the southern tip of Florida. This
A Model for Assessing Atmospheric
Deposition to the Great Waters
EPA has recently developed a new modeling tool
for the assessment of atmospheric deposition of
pollutants to the Great Waters. The Regulatory
Modeling System for Aerosols and Deposition
(REMSAD) is a work station-based Eulerian model
intended for use in assessing the impacts of regulatory
activities, such as the MACT standards, on loadings of
pollutants of concern to the Great Waters. REMSAD is
currently capable of simulating short-, medium-, and
long-range transport and deposition of cadmium,
dioxins, mercury, and POM. Nitrate deposition
distributions have been produced through REMSAD
simulation, but have not yet been compared to other
models such as RADM. Other pollutants, including
other toxics, be incorporated in future work. Initial
model demonstration and evaluation will be completed
during 1997. The model is currently available on the
OAQPS Support Center for Regulatory Air Models
(SCRAM) bulletin board.
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CHAPTER III
ATMOSPHERIC TRANSPORT AND DEPOSITION MODELS
area is divided in a grid, and for each grid cell the model considers pollutant emissions, transport
in and out of the cell, turbulent motion in the atmosphere, chemical reactions that produce or
deplete the chemical, vertical transport by clouds, and removal by dry deposition. RADM is
designed to model 140 chemical reactions among 60 pollutants, 40 of which are organic
compounds. A feature of RADM is the simultaneous modeling of sulfur and nitrogen deposition.
This is an important consideration because the amount of sulfur dioxide (SO ^ present in the
atmosphere affects the formation of both sulfates and nitrates and thus, the amount and spatial
distribution of nitrogen deposited back to waterbodies. RADM is also useful for analyzing long-
range transport issues, but it is very complex computationally. Recently, it has been applied to
the study of nitrogen deposition in the Chesapeake Bay watershed (Dennis 1997).9 The results of
this study are presented in Section IV.C. The limitations of this study, as well as more
background information on RADM, are presented in Dennis (1997).
AQSMs are limited by the quality of the algorithms used to simulate various processes
affecting pollutants of interest (e.g., chemical transformation, deposition), quality of input data
(e.g., emissions, meteorology), and lack or inadequacy of modeling of certain processes (e.g.,
air/water gas exchange). The quantity and quality of available input data is an important limiting
factor in the application of AQSMs, especially for atmospheric pollutants, such as many
pesticides and PCBs, that have relatively poorly developed emission inventories, or for which re-
emission and environmental cycling are significant.
Efforts sponsored by the Great Waters program are underway to improve the quality of
emission estimates for the HAPs, which historically have been inventoried only in a few places
and for short time intervals. In one effort, the eight states that border the Great Lakes have
worked together, with EPA, to develop an approved protocol for a coordinated emission
inventory of 49 HAPs, including the Great Waters pollutants of concern other than pesticides.
The inventories for point sources and area sources, as well as mobile sources, should be
completed by 1997-1998. The data are stored in a regional data base system (the Regional Air
Pollutant Inventory Development System, or RAPIDS) developed for this project. In another
effort, EPA is in the process of developing national inventories of sources and emissions for
seven specific HAPs (hexachlorobenzene, alkylated lead compounds, PCBs, POM, mercury,
2,3,7,8-TCDD, and 2,3,7,8-TCDF) in response to the mandate in section 112(c)(6) of the CAA.
III.C Comparing Models Used in Great Waters Studies
Several numerical atmospheric transport and deposition models or modeling strategies
have been and continue to be developed and used for understanding deposition of pollutants to
the Great Waters. Models have many roles in EPA's atmospheric programs and are widely used
to link emissions data, meteorology, receptor sites (e.g., people, or lakes, exposed to pollutants),
and monitoring of the ambient air (in cities, or over lakes for the Great Waters). New approaches
to modeling have been needed to deal with the particular complexities of the issues in Great
Waters studies. To discuss these models and their applications to the Great Waters with the
general scientific community, the EPA Great Waters program co-sponsored a session at the 15th
9 Work by Dennis (1997) models nitrate deposition only; however, ammonium and organic nitrogen deposition
may also be quantitatively important to the Bay.
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CHAPTER III
COMPARING MODELS USED IN GREAT WATERS STUDIES
annual meeting of the Society of Environmental Toxicology and Chemistry (SETAC) in 1994 on
"Atmospheric Deposition of Nutrients & Contaminants." Following that meeting, the presenters
and other scientists prepared written chapters for a SETAC Special Publication: Atmospheric
Deposition of Contaminants to The Great Lakes and Coastal Waters, J.E. Baker, editor (Baker 1997).
This section briefly describes the main applications and limitations of the models presented in
the SETAC session. This presentation is not intended to be a comprehensive list of all existing
models and their uses, as the development of transport and deposition models is a very active
research area. The document based on the SETAC session (Baker 1997) provides an in-depth
technical reference that supplements the information in this report.
Table III-l summarizes some of the relevant modeling efforts. These models are further
discussed below, with a very brief description of the model, its application to Great Waters
studies, and how the model compares with actual monitoring data; further information is
presented in Baker (1997).
The first modeling effort listed in Table III-l is the regional-scale analysis of nitrogen
deposition to the Chesapeake Bay watershed (Dennis 1997). The analysis was developed using
RADM, described in Section III.B. The overall goals of this study are, first, to define the source
region that contributes most of the nitrogen deposition affecting the Chesapeake Bay watershed
and, second, to define which source types are most responsible. The modeling results indicate
that the range of influence of nitrogen emissions is on the order of 800 kilometers (km) (though
this is considered a conservative estimate, given the model bias described in the study). The
model indicates that the source region for nitrogen deposition in the Chesapeake Bay watershed
is roughly 906,000 km2, or more than 5.5 times larger than the watershed. Dennis (1997) also uses
the model to analyze the spatial distribution of nitrogen deposition by emission sector. For
example, the model results indicate that utility emissions tend to be more responsible for
nitrogen deposition to the Bay basins themselves, while mobile emissions appear to influence
deposition to the mouths of the tributaries and the Bay itself. Additional results of this modeling
effort are presented in Section IV.C, although the study does not present any comparison to
monitoring data. The study does highlight the importance of additional research on the bias in
RADM for nitrogen deposition estimates, processes such as forest or terrestrial retention of
nitrogen, and the combined use of air-water models.
The second modeling analysis in Table III-l looks at wet and dry deposition of semi-
volatile organic compounds at a regional scale, with emphasis on the Great Lakes (Ching et al.
1997). The model used is a version of the Regional Particulate Model (RPM), which is itself a
modification of RADM that computes the chemical composition and size distribution of the
secondary sulfur and nitrogen species (Binkowski and Shankar 1993). Ching et al. (1997) use
RPM to analyze the size, chemical composition, and moisture content of airborne particles that
serve as sites for condensation and volatilization of semi-volatile organic compounds.
Deposition of semi-volatile organic compounds is tracked in the model as proportional to particle
deposition. This modeling effort is a step toward the use of regional-scale models to compute air
concentrations of these pollutants, and to provide benchmark testing of simpler and
computationally less demanding models. Some challenges ahead in this line of modeling
include better algorithms and data on air-water gas exchange, the role of clouds as both
transporters and chemical transformers, and modeling of resuspension of pollutants from
different land uses.
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COMPARING MODELS USED IN GREAT WATERS STUDIES
As presented in Table III-l, the numerical modeling of atmospheric mercury by Bullock et
al. (1997) uses the model RELMAP (Eder et al. 1986), described in Section III.B, with relatively
simple mercury parameterizations. An entire year of transport and deposition of airborne
mercury was simulated over the continental United States. The goals of this modeling effort
were to analyze the amount of mercury emitted to the air annually over the United States that is
deposited back to U.S. soils and waterbodies, the contribution of mercury by source category,
and the importance of long-range transport. The RELMAP-simulated annual results agree with
the majority of the limited annual deposition and concentration data available around the Great
Lakes and in Florida, as well as other areas, usually within a factor of two. Some RELMAP
estimates of wet deposition of mercury are somewhat high when compared to actual
measurements at those locations. However, the model cannot be well tested over the entire
model domain without annual observations in a large number of additional locations. The
limitations of this current research effort, including modeling of certain meteorological
conditions, aqueous chemistry of mercury, and transport and diffusion modeling are presented
in Bullock et al. (1997).
Pirrone and Keeler (1997) propose a hybrid receptor-deposition modeling approach to
estimate the dry deposition flux and air-water gas exchange of various HAPs to Lake Michigan.
The approach combines modeling of over-water transport of air masses and modeling of
deposition and gas exchange. The model parameters were calibrated using data from the Lake
Michigan Urban Air Toxics Study (LMUATS) to find both the temporal and spatial variation of
critical parameters controlling the transport and deposition of atmospheric contaminants. The
results of this study indicate large variations in the parameter values and hence the uncertainty
associated with the common practice of using constant parameter values for modeling. The
work by Pirrone and Keeler (1997) demonstrates a different approach to estimating surface flux
quantities that currently cannot be directly measured with confidence.
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TABLE 111-1
Summary of Atmospheric Transport and Deposition Models Applied to the Great Waters'
Model
Description of Model
Great Waters Related Application
Goodness of Fitb
References
Regional Acid
Deposition
Model
(RADM)
Developed under the NAPAPto predict
regional changes that may occur as a
result of nitrogen and sulfur deposition.
The geographic area covered by the
model is the eastern U.S. and Canada.
Project quantity and spatial distribution of
deposition to the Chesapeake Bay watershed
from sources in eastern U.S. and Canada.
Estimate fraction that each of 15 subregions in
the area contribute to total annual load of
atmospherically deposited nitrogen to the Bay
watershed and tidal waters.
Comparisons within a
factor of 2 for sulfur
deposition, and generally
within a factor of 2 for
nitrogen deposition.
Dennis
(1997)
Regional
Particulate
Model
(RPM)
Based on RADM; computes the chemical
composition and size distribution of the
secondary sulfur and nitrogen species, to
identify airborne particles that may serve
as sites for condensation or volatilization.
Predict wet and dry deposition of airborne
semi-volatile organic toxic compounds to the
Great Lakes on a regional scale.
Theoretical only and has
not been compared with
actual data.
Ching et al.
(1997)
Regional
Lagrangian
Model of Air
Pollution
(RELMAP)
Simulates concentrations of wet and dry
deposition patterns of gaseous pollutants
and particulate matter (both fine and
coarse), and can generate source-receptor
matrices for user-defined regions.
Model deposition of metals including cadmium
and lead to Lake Superior; model the
emission, transport, and fate of airborne
mercury in the U.S., including the Great Lakes
and Florida.
Wet deposition results
from RELMAP for
atmospheric mercury
agree with the majority of
actual measurements
within a factor of 2.
Bullock et al.
(1997)
Hybrid
receptor-
deposition
model
Uses backward trajectory calculations and
estimates dry deposition and gas
exchange flux. Parameters incorporated
into the model include transport distance,
meteorological conditions, particle size
distribution, and water surface roughness.
Estimate deposition of trace metals and semi-
volatile organic compounds to Lake Michigan
for the Lake Michigan Urban Air Toxics Study.
Experimental model;
variation in the model
depended on the nature
of the chemical species
and was ± 3-fold that of
values in literature.
Pirrone and
Keeler(1997)
a Models were presented at 1994 SETAC Annual Meeting and are described in Baker (1997).
b "Goodness of fit" refers to how well the deposition estimates from the models correspond to actual measured deposition data.
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CHAPTER IV
MAJOR WATERBODIES OF THE GREAT WATERS:
AN OVERVIEW OF PROGRAMS AND EFFORTS ADDRESSING ATMOSPHERIC DEPOSITION
Section 112(m) of the Clean Air Act specifically designates the Great Lakes, Lake
Champlain, Chesapeake Bay, and certain other U.S. coastal waters as waterbodies EPA is to
consider in identifying and assessing atmospheric deposition of hazardous air pollutants (HAPs)
to the Great Waters. Researchers have found that the Great Waters have been affected by metals,
pesticides, toxic chemicals, and nutrients that enter the waters through different pathways,
including atmospheric deposition.
This chapter presents information currently known about contamination occurring at the
individual Great Waters, including problems or issues that challenge each waterbody, followed
by discussion of current strategies or efforts to respond to these concerns. Most of the infor-
mation has been generated from activities occurring at the Great Lakes and Chesapeake Bay. In
the Great Lakes, several initiatives have been introduced in recent years, ranging from research
projects to gather quantitative estimates of atmospheric loadings to regulatory and voluntary
activities promoting reduction of loadings to the waterbody. Efforts at Chesapeake Bay have
focused on developing models to improve characterization of nitrogen and toxic contaminant
loadings, as part of major reduction strategies. Research is more limited for Lake Champlain and
for the other coastal waters. In these waterbodies, smaller-scale investigations have been carried
out to study certain pollutants of concern in their respective waterbodies, and in many cases,
comprehensive strategic plans have been developed to address contamination issues.
This chapter is organized by sections on each of these major waterbodies of the Great
Waters and divided accordingly:
• Section IV.A presents information available on atmospheric deposition of
persistent toxic pollutants into the Great Lakes and the many programs to
characterize and reduce loadings;
• Section IV.B describes Lake Champlain and current research to assess atmospheric
mercury deposition in the basin;
• Section IV.C discusses the deposition of nitrogen and toxic pollutants to
Chesapeake Bay and the related monitoring and modeling efforts; and
• Section IV.D provides an overview of U.S. estuary programs and some major
efforts to characterize loadings of nitrogen and toxic pollutants to coastal waters.
Although this chapter describes current data and programs specific to the subject waterbody,
much of the information is relevant to other waters as well. For example, those interested in
smaller estuaries will gain insight from information presented in the Chesapeake Bay section.
The Great Lakes and Lake Champlain represent two important freshwater systems in the
United States. Lakes are sensitive to pollution inputs because they lack any dominant,
unidirectional flow, and as a result, there is a slow change of water and a resulting retention of
pollutants.
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CHAPTER IV
MAJOR WATERBODIES OF THE GREAT WATERS
The Great Lakes contain approximately one-fifth of the world's supply of fresh surface
water. These lakes have played a vital role in the history and development of the United States
and Canada. They are stressed by a wide range of pollution sources associated with the large
urban centers located on their shores. Because the Great Lakes system is a relatively closed water
system (very large volume, with relatively small water inflows and outflows), many of the
pollutants that reach the Great Lakes remain in the system for extended periods of time. For
example, Lake Superior replaces all the water in the lake every 191 years, Lake Erie every 2.6
years.
Lake Champlain is located in the northeastern United States, shared by the states of New
York and Vermont and the Province of Quebec. Although much smaller in surface area than the
Great Lakes, Lake Champlain is still one of the largest freshwater lakes in the United States and
its natural resources are important to the local economy. The Lake Champlain basin, or
watershed, is much larger relative to its water surface area than the Great Lakes, and so
watershed throughput is much more of an issue for Lake Champlain. Toxic pollutants are an
issue of wide public concern in the Lake Champlain Basin, due in large part to fish consumption
advisories for PCBs and mercury issued by both New York and Vermont, and the potential
impact on drinking water and the Lake's many other uses.
"Coastal waters," for the purposes of CAA section 112(m), are defined as those estuaries
designated for the National Estuary Program (pursuant to section 320(a)(2)(A) of the federal
Water Pollution Control Act) or designated for the National Estuarine Research Reserve System
(pursuant to section 315 of the Coastal Zone Management Act). Chesapeake Bay is identified by
name in section 112(m).
Estuaries occur where rivers empty into the ocean, mixing together fresh water and salt
water, and creating an ecosystem distinct from, and often more productive than, either fresh or
salt water systems. Estuarine waters include bays, sounds, marshes, swamps, inlets, and sloughs.
These environments are characterized by varying degrees of salinity, high turbidity levels, and
complex water movement affected by ocean tides, river currents, and wind. Estuaries are critical
coastal habitats that serve as spawning grounds, nurseries, shelters, and food sources for many
different species of shellfish, fish, birds, and other wildlife. The leading environmental problems
in estuarine systems at present are eutrophication,10 contamination by toxic chemicals and
pathogens (disease-causing organisms), over-harvesting, and loss of habitat.
In 1975, Chesapeake Bay became the nation's first estuary to be targeted for protection
and restoration. Over the past decade, other coastal programs, such as the National Estuary
Program, the National Estuarine Research Reserve System, and the Gulf of Mexico Program,
have been established to protect and restore water quality and living resources in U.S. estuaries
and coastal waters. Chesapeake Bay was also among the first estuaries where atmospheric
sources of nutrients and toxic pollutants were recognized as significant inputs to the waterbody.
Recently, research on other U.S. coastal waters has begun to evaluate the loadings of nutrients
and toxic pollutants to their watersheds from atmospheric sources. The Great Waters program
has focused primarily on Chesapeake Bay for estuarine issues, and has found that information
developed for this waterbody is generally applicable to several other East Coast estuaries, when
10 As discussed in Section II.D and in this chapter, eutrophication is over-enrichment of waters that is characterized
by algae blooms, turbid waters, and low or no dissolved oxygen conditions.
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CHAPTER IV
MAJOR WATERBODIES OF THE GREAT WATERS
adjustments are made for respective waterbody's physical, chemical, and geomorphological
characteristics.
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CHAPTER IV
MAJOR WATERBODIES OF THE GREAT WATERS
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CHAPTER IV
THE GREAT LAKES
IV.A The Great Lakes
The Great Lakes, comprised of Lakes Superior, Michigan, Huron, Erie, and Ontario, are
an important part of the physical, cultural, and industrial heritage of North America (see Figure
IV-1). The Great Lakes ecosystem, the interacting components of air, land, water, and living
organisms, including humans, is one of the largest surface systems of freshwater on earth. This
ecosystem contains 18 percent of the world's freshwater supply and 95 percent of the surface
freshwater within the United States. Only the polar ice caps and Lake Baikal in Siberia contain
more freshwater than the Great Lakes. By virtue of their size, the Great Lakes affect the climate
of the surrounding region. Areas of Michigan, Ontario, and New York generally have warmer,
though snowier, winters than other parts of North America at similar latitudes because, as a
result of little continual current, the lakes retain a large amount of heat. In spring and early
summer, the lakes are slow to warm, thereby keeping the nearby land areas cool.
The Great Lakes sustain a rich
diversity of fish, birds, and other wildlife.
Native fishes important for commercial and
recreational harvest include lake trout, lake
whitefish, and walleye. Non-native species
such as smelt, white perch, brown trout,
rainbow trout, and several Pacific salmon
species also contribute substantially to the
total annual fish harvest. Approximately
three million waterfowl follow the Atlantic
and Mississippi flyways through the Great
Lakes basin each year. Native animals
include deer, fox, moose, wolves, beaver,
mink, and muskrat. In addition, the Great
Lakes ecosystem supports more than 100
globally endangered or rare species (Nature
Conservancy 1994).
The Great Lakes basin is home to
more than 33 million people, including
10 percent of the U.S. population and 25 percent of the Canadian population. Over 23 million of
these people depend on the Great Lakes for drinking water. Industries use the water to make
products, to cool manufacturing processes or power generation equipment, and to ship raw
materials and finished products. Residents and visitors alike enjoy an abundance of recreational
activities, including boating, swimming, fishing, sightseeing, camping, and hiking.
The concentration of human activities in the Great Lakes basin (e.g., manufacturing,
transportation, agriculture, fishing) imposes stresses on the ecosystem and has prompted
significant concerns for the health and well-being of the human residents. Many of the major
stressors and resultant effects were documented in the First Great Waters Report to Congress.
The current report builds on this information and presents some of the potential problems that
may affect the Great Lakes basin from the perspective of the CAA, and major programs that are
underway to address those problems.
Economic Highlights of the Great Lakes
• Approximately 11 % of total employment and
15% of manufacturing employment of
combined U.S. and Canadian workers are
located in the Great Lakes basin.
• Trade between Canada and the eight Great
Lakes States in 1992 was valued at $106
billion (56.2% of the U.S.-Canada total).
• An estimated 900,000 to 1 million U.S. and
Canadian boats operate each year, resulting
in a direct spending impact on the regional
economy of more than $2 billion.
• About 2.55 million U.S. anglers fish the Great
Lakes; total trip-related and equipment
expenditures were $1.33 billion in 1991.
Source: Allardice and Thorp 1995.
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CHAPTER IV
THE GREAT LAKES
FIGURE IV-1
Great Lakes Basin
Physical Features of the Great Lakes
Volume (km3)
Maximum Depth (meters)
Water Area (km2)
Land Drainage Area (km2)
Retention Time (years)
Superior
12,100
406
82,100
127,700
191
Michigan
4,920
282
57,800
118,000
99
Huron
3,540
229
59,600
134,100
22
Erie
484
64
25,700
78,000
2.6
Ontario
1,640
244
18,960
64,030
6
Totals
22,684
NA
244,160
521,830
NA
NA = not applicable
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CHAPTER IV
THE GREAT LAKES
The remainder of Section IV.A presents:
• Current knowledge and recent
measurements of atmospheric
levels and deposition of toxic
pollutants to the Great Lakes;
• Information on major
activities/programs currently in
progress to assess atmospheric
deposition of air pollutants to the
Great Lakes;
• Efforts supported by the United
States, as well as Canada, to
reduce and mitigate atmospheric
emissions in the Great Lakes
basin; and
• Brief discussion on current
information gaps, and future
research needs to improve
understanding of atmospheric
deposition of pollutants into the
Great Lakes.
Atmospheric Deposition of Great
Lakes Contaminants
Hundreds of anthropogenic chemicals
have been identified in the Great Lakes
ecosystem. High levels of certain
bioaccumulative pollutants remain in certain fish
and wildlife species, and fish advisories have
been issued by many Great Lakes states for
several pollutants of concern, specifically chlordane, dioxins, mercury, PCBs, and toxaphene
(specific advisories are listed in Appendix B). For example, although concentrations of PCBs and
DDT in Lake Michigan lake trout are currently about one-tenth of those of 20 years ago (Figure
IV-2), the concentrations are still at levels that warrant issuance of public health advisories
regarding the consumption of these fish. Advisories may especially apply to specific
subpopulations, such as children and women who are pregnant or anticipate bearing children.
The pollutants of concern have been associated with health problems in certain fish and
wildlife species, although with the decline of some pollutant levels, many species may be
recovering. For example, the number of double-crested cormorants living on the Great Lakes has
increased more than 20-fold during the past 15 years. Prior to this, numbers of these fish-eating
birds declined during the 1970s due to reproductive failure from DDE-induced egg shell
thinning. Health problems persist for fish and wildlife in certain locations, particularly in waters
Common Terminology for Pollutant
Movement in a Waterbody
FLUX
Transport of a chemical across an interface
(e.g., between air and water) for a given
area and time, accounting for both inputs
and outputs. Net flux is equal to all positive
loadings minus all negative loadings.
INPUTS (positive loading)
Wet Deposition: Gases and particles
carried in precipitation (rain, snow, sleet)
and deposited on land and water surfaces.
Dry Particle Deposition: Pollutants,
bound to particles, deposited on land and
water surfaces in the absence of
precipitation.
Gas Absorption: Gaseous form of
pollutants crossing air-water interface into
the water (portrayed as a positive number
in a flux calculation).
Waterborne Discharge: Pollutants
discharged directly to water (e.g., by
industrial discharge, urban storm-runoff).
Tributary Loading: Pollutants entering
waterbody through connecting channels,
streams, and rivers.
OUTPUTS (negative loading)
Volatilization or Gas Evasion: Gaseous
form of pollutants crossing air-water
interface into the air (portrayed as a
negative number in a flux calculation).
Sedimentation: Settling of particles by
gravity to bottom sediments.
Outflow: Pollutants flowing with water out
to rivers or to the ocean.
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CHAPTER IV
THE GREAT LAKES
Figure IV-2
PCBs and DDT in Lake Trout from Lake Michigan
I
\ I I I I I
1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992
Year
with highly contaminated bottom sediments, and for predators high in the food web, such as
lake trout, mink, and bald eagles.
During the 1980s, studies in the Great Lakes showed that atmospheric deposition may be
a major route of introduction of a number of pollutants to the Great Lakes. For example,
atmospheric transport of toxaphene was implicated when the insecticide was found in fish in
Lake Siskiwit, located on an island in Lake Superior Because the elevation of Lake Siskiwit is
above that of Lake Superior, it does not receive any groundwater from Lake Superior and thus
pollutant input. This pesticide was used mainly on cotton crops in the southern United States,
prior to its cancellation in 1982 (McVeety and Kites 1988).
As a result of this and other findings, the United States and Canada established a joint
monitoring network called the Integrated Atmospheric Deposition Network (IADN). The IADN
is designed to assess the magnitude and trends of atmospheric deposition of target chemicals to
the Great Lakes, and to determine emission sources wherever possible. The program responds
to the Great Lakes Water Quality Agreement (GLWQA) between the United States and Canada,
specifically to the needs of Annex 15 which addresses issues concerning airborne contaminants
in the Great Lakes basin. A more detailed discussion of the rationale, design, and results of the
IADN, as well as the uncertainties that exist in calculating atmospheric deposition estimates, is
presented in the following subsection (Program Actions to Characterize Atmospheric
Contamination in Great Lakes).
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CHAPTER IV
THE GREAT LAKES
The first consensus data
report for IADN (Eisenreich and
Strachan 1992) revised and
improved the very broad
estimates of atmospheric
deposition of toxic contaminants
that were previously compiled
(Strachan and Eisenreich 1988).
More recent data were
incorporated into deposition
estimates for 1994 and compared
to the earlier results (Hoff et al.
1996), as shown in Table IV-1. A
general decline in some pollutant
levels is suggested from the
estimates in Table IV-1. Average
estimated atmospheric loadings of
certain pollutants to the five Great
Lakes between 1991 and 1993 are
presented in Table IV-2. The data
in Tables IV-1 and IV-2 may not be
comparable because the estimates
represent measurements at
different time frames. It is
important to recognize that the
values presented in these tables
are based on preliminary data and
limited samples. Furthermore,
contributions from water inputs
and outputs are not included. As
such, overall loadings to the lakes
cannot be established from these
data alone.
TABLE IV-1
Atmospheric Loading Estimates for Selected
Pollutants (kg/year) in the Great Lakes
Pollutant of
Concern
PCBsa(Wetand
1988
1992
1994
PCBsa (Net Gas
1988
1994
Superior
Dry)
550
160
85
Transfer)"
-1900
-1700
Michigan
400
110
69
-5140
-2700
Huron
400
110
180
-2560
—
Erie
180
53
37
-1100
-420
Ontario
140
42
64
-708
-440
DDT (Wet and Dry)
1988
1992
1994
90
34
17
64
25
32
65
25
37
33
12
46
26
10
16
DDT (Net Gas Transfer)
1988
1994
Benzo(a)pyrene
1988
1992C
1994
-681
30
-480
67
-495
—
-213
34
-162
13
(Wet and Dry)
69
120
200
180
84
250
180
84
-
81
39
240
62
31
120
- Not determined or reported.
a Data presented for PCS congeners 18, 44, 52, and 101 (each
with 3-5 chlorines in chemical structure).
b The convention is to assign a negative number to loss of
pollutant from the lake (i.e., volatilization). Thus, the resulting
number expresses the mass of a pollutant going into or coming
out of the lake per year (i.e., a positive net gas transfer indicates
a net input of the pollutant to the lake and a negative net gas
transfer indicates a net loss or output from the lake).
c Data from 1992 may represent an underestimation in the
measurement of benzo(a)pyrene.
Sources: Eisenreich and Strachan 1992; Hillery et al. 1996; Hoff
et al. 1996; and Strachan and Eisenreich 1988.
Atmospheric loadings of
pollutants are calculated using
atmospheric concentration data
gathered by IADN and estimates
for various parameters such as lake surface area. The wet deposition data are based on estimated
annual precipitation rates, and do not use actual rainfall amounts. Although uncertainties exist
for the parameters which can lead to some degree of error, the atmospheric deposition estimates
are based on the best scientific data currently available.
The remainder of this subsection presents atmospheric concentration and deposition data
collected primarily from IADN on some pollutants of concern, as well as information on current
trends of pollutant deposition. The pollutants of concern discussed include PAHs, PCBs,
pesticides (e.g., DDE, DDT, lindane, toxaphene), and trace metals (e.g., lead, mercury). PCBs,
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TABLE IV-2
Average Estimated Atmospheric Loadings3 of Selected Pollutants
to the Great Lakes (kg/year) (1991-1993)
Atmospheric Processb
PCBs
Wet deposition
Dry deposition
Net gas transfer0
Absorption
Volatilization
Dieldrin
Wet deposition
Dry deposition
Net gas transfer
Absorption
Volatilization
DDE
Wet deposition
Dry deposition
Net gas transfer
Absorption
Volatilization
Lindane
Wet deposition
Dry deposition
Net gas transfer
Absorption
Volatilization
Benzo(a)pyrene
Wet deposition
Dry deposition
Net gas transfer
Absorption
Volatilization
Lake Superior
58
27
-1700
320
-2000
21
7.4
-780
120
-910
2.6
0.4
—
10
—
62
0.6
140
340
-200
140
58
87
100
-17
Lake Michigan Lake Huron
52 180
16
-2700
390
-3100
58 10
8
—
200
—
3.8 10
0.5
—
26
—
65 140d
1.1
1200
1400
-140
170
77
—
92
—
Lake Erie
21
16
-420
340
-760
28
5.6
-610
67
-680
4.6
0.5
—
14
—
46
0.4
61
180
-110
180
63
—
51
—
Lake Ontario
58
5.7
-440
130
-560
11
1.7
-320
43
-370
4.5
0.2
-170
12
-180
51
0.2
16
72
-56
56
60
—
7.5
—
a., . . . . ,, . , . . ,. .. and based on atmospheric concentration data collected
Values calculated from atmospheric loading equations,
from Integrated Atmospheric Deposition Network (IADN); summarized from Hoff et al. (1996).
b Wet deposition based on estimated annual precipitation rates, and does not use actual rainfall amounts.
Dry deposition represents only data for particle form of pollutant (i.e., gaseous form included in absorption values).
c Net gas transfer is the sum of gas absorption and volatilization. Water concentration data are taken from past
literature and compared with the more recent air measurements, which may lead to some potential error in gas
transfer estimates. Values for net gas transfer are rounded off and thus estimates may not add up in the table.
"High estimated value may be due to very limited number of samples for 1992 season and should be
reconsidered as more data become available (Hoff et al. 1996).
— Not determined or reported.
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toxaphene, and mercury are given greater focus because fish advisories are currently issued for
these pollutants. Fish advisories also exist for chlordane and dioxins for the Great Lakes, but
they are not addressed in this section because recent information is limited. Potential sources of
the pollutants are also discussed, as well as uncertainties in the data.
PAHs
Polycyclic aromatic hydrocarbons (PAHs), a subset of POM, are a class of semi-volatile
compounds produced in combustion processes and are widely distributed in the environment.
As indicated in the First Report to Congress, approximately 72 to 96 percent of the total annual
loading of one common PAH, benzo(a)pyrene, to Lakes Superior, Michigan, and Huron is
attributed to atmospheric deposition.
PAHs are detected both in the gaseous and particulate phases, but some of the most toxic
PAHs are largely in the particulate phase in the atmosphere. For the most toxic PAHs, dry
deposition is generally the main route of deposition to the lakes (Hoff and Brice 1994). For
benzo(a)pyrene, however, wet deposition seems to be the major source of atmospheric loadings
to Lake Michigan in all seasons of the year. The IADN data suggest that, for Lake Superior, the
net movement of the gaseous phase benzo(a)pyrene is largely to the water; data are limited for
the other lakes (see Table IV-2). Comparing recent wet and dry deposition values with historic
data, the loading of benzo(a)pyrene to the lakes appears to have increased (Table IV-1).
However, the 1992 finding may be attributed to an underestimation in the measurement of
benzo(a)pyrene (Hoff et al. 1996).
A recent study found that total wet and dry deposition for benzo(a)pyrene was 50 times
higher at an urban site (Chicago) than at remote IADN sites in Lakes Michigan and Superior
(Sweet and Harlin 1996). The investigators concluded that large areas of Lake Erie, Lake Ontario,
and southern Lake Michigan have elevated PAH deposition rates due to emissions from nearby
urban areas. Although the total deposition of PAHs are lower in rural than urban sites, the rela-
tive amounts of the individual PAHs (i.e., relative ratios of the individual PAHs) is very similar at
urban and nonurban sites, suggesting that little chemical degradation occurs during transport of
PAHs from urban source areas to rural and remote sites several hundred kilometers away.
PCBS
PCBs are a class of highly toxic, persistent, and bioaccumulative chemical compounds.
PCBs in Great Lakes fish have long been linked to developmental and growth problems in
infants born to women who regularly consumed PCB-contaminated fish in the late 1970s. PCBs
were produced from 1927 to 1977 for the purpose of insulating and cooling electrical equipment.
In the late 1970s, Monsanto Company, sole manufacturer of PCBs in the United States,
voluntarily stopped production of PCBs. Estimates suggest that 282 million pounds of pure
PCBs -- 20 percent of PCBs ever produced — were still in service at the end of 1988.
PCBs manufactured before production was stopped are still found in the Great Lakes.
They are present in older commercial and industrial equipment (e.g., transformers, capacitors).
There are no phaseout deadlines that require removal of the equipment to avoid breakage and
release, although this equipment is tightly regulated under the Toxic Substances Control Act
(TSCA). As a result of past use and disposal practices, PCBs may reside in sediments in surface
waters and in other areas, such as waste sites. As the contaminated sediment is disturbed, the
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CHAPTER IV
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PCBs may be re-released and resuspended in the water, allowing for continued bioaccumulation
in Great Lakes fish. Remediation programs are in-place to address PCB-contaminated waste
sites. Other continuing PCB sources include unregulated sources that potentially contain PCBs
and releases, as well as releases by those PCB owners who are not aware of the presence of PCBs
or of the special management requirements for PCB-containing equipment.
Despite the fact that PCBs are one of the most tightly regulated and controlled group of
pollutants under federal regulatory programs, fish consumption advisories still exist for PCBs in
all five of the Great Lakes (see Appendix B). For example, although PCB levels have declined in
Lake Michigan water, there has been a constant or increasing level of PCBs in some Lake
Michigan fish in the last few years, possibly due to resuspension from sediment or from changes
in the Lake Michigan food chain (see Section II.B).
Volatilization is the dominant mechanism in air-water gas exchange of PCBs (Table IV-2).
Volatilization of PCBs from the Great Lakes is estimated to be as high as 3,100 kg/year for Lake
Michigan and 2,000 kg/year for Lake Superior. In contrast, estimates of wet deposition of PCBs
are less than those for volatilization and are nearly the same for Lakes Superior, Michigan, and
Ontario (52-58 kg/year) with Lake Erie showing a lower rate (21 kg/year) and Lake Huron
showing the highest rate (180 kg/year) (Table IV-2). Dry deposition rates of PCBs are similar in
Lakes Superior, Michigan, and Erie (16-27 kg/year), with Lake Ontario showing a lower rate (5.7
kg/year). As presented in Table IV-1, from 1988 to 1994, wet and dry deposition of PCBs to each
of the Great Lakes has decreased. Therefore, the net loss to the atmosphere would suggest that
the amount of PCBs in water is declining. Tables IV-1 and IV-2, however, represent data only for
the atmospheric movement of pollutants and therefore, do not indicate the waterborne inputs to
each lake (such as particles in the water, industrial water discharges, and especially urban storm-
runoff which goes directly into the lakes). Also, this study on gas exchange is preliminary and
there are considerable uncertainties in the estimates. Additional work addressing the
uncertainties and other routes of pollutant movement may give a different balance, although the
importance of gas exchange is clear.
Wet and dry deposition of PCBs are similar over seasons, while net gas exchange is
highly seasonal, exhibiting much greater effect with high temperatures (Figure IV-3). To date,
no studies on seasonal variation in PCB concentrations in water have been published to compare
with the seasonal atmospheric loading data. As stated earlier, uncertainties exist in calculating
deposition estimates, since some estimates are based on rough approximations or assumptions
using the best science available at this time.
PESTICIDES
Volatilization of the pesticides dieldrin and DDE (a metabolite of DDT) in many of the
Great Lakes is a significant process. Net atmospheric loading is negative, indicating that
movement of these two pesticides between air and water is mostly volatilization (Table IV-2).
Fluctuations in gas equilibrium conditions may be influenced by the water concentration data,
differences in temperature, and/or errors in the Henry's Law constant used in calculating gas
movement. For example, DDT net gas transfer estimates are hindered by difficulties in obtaining
precise water concentration data because DDT levels in the lakes are close to the analytical
detection limit. From Table IV-1, DDT wet and dry deposition loadings declined between 1988
and 1992, but rose slightly for all lakes except Lake Superior in 1994 (Hillery et al. 1996).
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FIGURE IV-3
Seasonal Atmospheric Loadings of PCBs in Lake Michigan (1994)
-200
-400
m wet deposition
D dry particle deposition
• volatilization
0 net gas transfer
-600
-800 - -T
-1000--
-1200
Winter
Spring
Summer
Wet and dry deposition of lindane appeared to be fairly uniform across all lakes (see
Table IV-2). Gaseous lindane generally seemed to be in equilibrium within Lakes Erie and
Ontario, while gas absorption is the dominant mechanism in air-water exchange for Lakes
Superior and Michigan (Table IV-2). The net gas transfer of lindane in Lake Michigan is into the
lake in the winter and spring and out of the lake in the summer and fall. For many pesticides,
gas transfer is strongly dependent on seasons, with net outputs in the summer and net inputs in
the winter (Achman et al. 1992; Hoff et al. 1993; McConnell et al. 1992; Ridal et al. 1996).
Toxaphene in the Great Lakes Basin.
Toxaphene, a semi-volatile insecticide
containing a mixture of chlorinated bornanes
(class of aromatic hydrocarbons), has been
recognized as one of the contaminants with
the highest concentrations in Great Lakes
fish (Ribick et al. 1982; Schmitt et al. 1981,
1985,1990). Because of its volatility and
persistence, toxaphene is still widely
distributed through the atmosphere, even
though it is no longer used in the United
States (Rapaport and Eisenreich 1986).
Toxaphene was been found to be a major contaminant in lake trout and whitefish from Siskiwit
Lake on Isle Royale, Lake Superior (De Vault et al. 1996) (see sidebar).
Toxaphene in Lake Trout
Since 1991, the state of Michigan has issued a
consumption advisory for Siskiwit lake trout from
Lake Superior based on exceedance of the FDA's
5.0 ppm action level for toxaphene. In 1995, the
Canadian Province of Ontario issued fish consump-
tion advisories for several different species in Lake
Superior and upper Lake Huron, triggered by their
toxaphene levels and a lowering of Health Canada's
action level for toxaphene to 0.2 ppm.
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Toxaphene's discovery on pristine Isle Royale, exposed only to atmospheric deposition,
seemed indicative of long-range transport via the atmosphere since it had been used primarily as
a pesticide in the southern United States (Hoff et al. 1993). This hypothesis has been supported
by studies that found toxaphene concentrations in Canadian air masses that had originated in
the southern United States. However, there is also evidence to suggest that some of the
toxaphene found in Lake Superior and northern Lake Michigan may have local origins. A study
that analyzed fish from rivers in the southeastern United States, the Great Lakes, and Isle Royale,
collected during 1982, found differences in composition of toxaphene in fish between sites,
suggesting that potential local influence may be important, rather than long-distance
atmospheric transport from the southeastern United States to the Great Lakes (Petty et al. 1987).
EPA recently supported monitoring of toxaphene in Great Lakes fish and sediment which
has revealed two trends. First, there has been a statistically significant decline in the
concentration of toxaphene in fish from most waters, as might be expected following reduced
use and later cancellation of the pesticide. Second, there has been no discernible decline in
toxaphene levels in Lake Superior lake trout; toxaphene levels are higher than levels of other
measured contaminants in fish from anywhere in the Great Lakes.
At this time, there are several hypotheses for the relatively elevated levels of toxaphene
observed in Lake Superior and northern Lake Michigan. First, the continued use of toxaphene
by other countries and subsequent atmospheric transport to the Great Lakes basin may increase
levels. Another possibility is the previous local use of the pesticide. Toxaphene was once used to
kill undesirable fish communities (Lockhart et al. 1992; Stern et al. 1993). This practice occurred
in parts of Canada and the northern United States for fish restocking on small glacial lakes; it was
applied to at least 80 lakes during the 1950s and 1960s in Wisconsin (Hughes 1968). It has also
been proposed that Lake Superior lake trout may be slower to reflect a decrease in contaminant
levels in their food web due to their greater age; however, Glassmeyer et al. (1997) found that
toxaphene levels in Lake Superior fish were still elevated compared to levels in fish from the
other lakes. Another explanation that has been suggested is that toxaphene persists longer in
colder, less productive waters such as Lake Superior. Finally, the high toxaphene levels may be a
result of the release of toxaphene into the waters as a byproduct in the production of paper;
there are 74 pulp and paper mills that directly discharge to all the Great Lakes (IJC 1995), with
the paper industry most concentrated near Lake Superior and upper Lake Michigan (Green Bay).
TRACE METALS
A number of trace metals are of concern in the Great Lakes, though new data are limited.
Data from 1994 suggest that wet deposition is the dominant atmospheric transport mechanism
for trace metals to the Great Lakes (Hoff and Brice 1994). The most consistent trend in the
deposition of trace metals was the reduction in lead in 1994 compared with 1988 values for all the
lakes (Figure IV-4). This finding is not surprising given the phaseout of leaded gasoline in the
United States beginning in the 1970s and accelerating in the mid-1980s. The gaseous phase of
lead is assumed now to be negligible. Arsenic deposition also has decreased. The reason for this
finding is not as clear but it has been hypothesized that process changes by Noranda, a major
emitter of arsenic in Canada through mining, smelting, and refining of metal products, may have
led to the decline.
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CHAPTER IV
THE GREAT LAKES
FIGURE IV-4
Atmospheric Loadings of Lead to the Great Lakes (1988-1994)
600,000
500,000
400,000
300,000
200,000
100,000
• Lake Superior
0 Lake Michigan
D Lake Huron
El Lake Erie
• Lake Ontario
1988
1992
1994
Mercury in the Great Lakes Basin. Currently, six of the eight Great Lakes states (Michigan,
Ohio, Wisconsin, New York, Pennsylvania, and Minnesota) have issued advisories restricting
consumption of fish from some state waters due to mercury contamination. Mercury contamina-
tion, or high mercury levels in fish tissue, is also the most frequent basis for fish advisories issued
by the Province of Ontario. Many of their advisories are applicable to areas of the Great Lakes.
During the early 1970s, mercury was found in fish from Lake Huron, Lake St. Clair,
western Lake Erie, eastern Lake Ontario, and the St. Lawrence River at levels that led the United
States and Canada to close commercial fisheries. Subsequently, mercury levels fell in these
waters, because of modification or closure of certain chloralkali facilities and pulp and paper
mills whose wastewater discharges contained large quantities of mercury. In 1970, mercury
levels in Lake St. Clair walleye were 2 parts per million (ppm); by the mid-1980s, levels in these
walleye had subsided to 0.5 ppm (Environment Canada et al. 1991). There are other signs of
reduced mercury levels in the Great Lakes through dated sediment cores and populations of
smelt in the lakes.
Because of large direct discharges of mercury being terminated following implementation
of the Clean Water Act (CWA), the atmosphere is now the dominant pathway by which mercury
reaches the Great Lakes. Currently, the best estimate of atmospheric deposition to the five Great
Lakes is approximately 6,800 kg per year (15,000 pounds) (Eisenreich and Strachan 1992).
Loadings of mercury to Lakes Superior and Michigan are primarily from the atmosphere. For
Lake Ontario, the percentage of atmospheric contribution of mercury is relatively modest
because the lake receives mercury from waters that flow from the upper lakes (Sitarz et al. 1993).
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CHAPTER IV
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Even some of the mercury borne to the Great Lakes via their tributaries includes contamination
previously deposited from the atmosphere to their watersheds.
Unlike other trace metals, mercury exists in the air predominantly in the gaseous phase
due to its volatility. Estimates of wet and dry deposition of mercury to Lake Superior are about
five times higher than net gas transfer to the atmosphere. The net annual atmospheric loading of
mercury to Lake Superior is calculated to be about 635 kg/year (Hoff et al. 1996), which is
comprised of the following estimates:
• 560 kg/year as wet deposition;
• 250 kg/year as dry deposition;
• 65 kg/year as absorption; and
• -240 kg/year as volatilization.
In an earlier study, gaseous phase mercury in the atmosphere was 1.57 ng/m3, particulate phase
mercury, 0.02 ng/m3, and precipitation mercury, 10.5 ng/L, at a northern Wisconsin site near Lake
Michigan (Fitzgerald et al. 1991). Comparison of these values with other U.S. sites is presented in
Table IV-5 in Section IV.B.
In Michigan, atmospheric concentrations and wet deposition of mercury have been
observed to vary geographically. Northern Michigan received only one-half the wet deposition
of mercury deposited to southern portions of the state. Wet deposition varied by season, with
mercury concentrations in precipitation two times greater during spring and summer than
during winter. Higher levels of particulate mercury were observed in large urban areas.
Modeling indicated that the dominant sources of mercury were located mostly to the south and
west of Michigan (Keeler and Hoyer 1997).
Program Actions to Characterize Atmospheric Contamination in the Great
Lakes
Research has occurred in the past few years to increase understanding of the effects, fate,
and transport of toxic substances in the Great Lakes ecosystem. These efforts are designed to
provide information to further characterize, as well as reduce, atmospheric contamination in the
Great Lakes region. Some of the programs to assess the extent of atmospheric contamination in
the Great Lakes basin are described below. At this time, many of these projects are collecting
and/or compiling data, and results are not yet available for evaluation. Also, several notable
programs/activities have been introduced in recent years to begin to reduce loadings and to
mitigate existing contamination and are discussed in the following section (Toxics Reduction
Efforts in the Great Lakes).
LAKE MICHIGAN MONITORING PROGRAM
A monitoring program for Lake Michigan has been implemented by EPA's Great Lakes
National Program Office to support a number of activities that address reductions in the release
of toxic substances, particularly persistent, bioaccumulative substances, to the Great Lakes
system. The program is a key element of the Lakewide Management Plan (LaMP) for Lake
Michigan (see next subsection, Toxics Reduction Efforts in the Great Lakes, for general
information about the objectives of LaMPs).
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CHAPTER IV
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The water quality criteria and values provided in the GLWQ Guidance, once adopted by
the Great Lakes states, would apply to the entire Great Lakes system, regardless of the source of
pollutants to those waters. In this manner, the proposed water quality criteria and the measured
values provide the basis for integrating actions carried out under the range of environmental
programs available to federal, state, and tribal agencies to protect and restore the Great Lakes
ecosystem. The mass balance approach will facilitate this integration by evaluating multi-media
load reduction actions required to ensure that Lake Michigan water quality meets the Great
Lakes water quality criteria (GLWQC).
The primary goal of the Lake Michigan Monitoring Program is to develop a sound,
scientific base of information to guide future toxic load reduction efforts at federal, state, tribal,
and local levels. In particular, the following specific objectives are identified:
• Evaluate relative loading rates of critical pollutants by medium (atmospheric
deposition, contaminated sediments, tributaries) to establish a baseline loading
estimate to gauge future progress;
• Develop the predictive ability to determine the environmental benefits of specific
load reduction scenarios for toxic substances and the time required to realize
those benefits, including evaluation of benefits of existing environmental statutes
and regulations; and
• Improve our understanding of the key environmental processes that govern the
cycling and bioavailability of contaminants within relatively closed ecosystems.
Lake Michigan Mass Balance
Study. One of the ways to address the
objectives of the Lake Michigan
Monitoring Program, as well as to assist
EPA in implementing section 112(m) of
the CAA, is through a mass balance
study. The mass balance study will
characterize the loadings, transport, and
fate of selected pollutants in a defined
ecosystem, through monitoring and
modeling. These measuring and
estimating techniques can be applied to
other ecosystems. EPA initiated the Lake
Michigan Mass Balance Study, a com-
prehensive sampling effort that includes
measurements of contaminants in the
atmosphere, tributaries, lakewater, sediments, and food chain, to support model components.
The atmospheric sampling sites for this mass balance study are shown in Figure IV-5.
The Lake Michigan Mass Balance model is constructed for a limited group of pollutants
(PCBs, trans-nonachlor [a bioaccumulative component of chlordane], and total mercury) present
in Lake Michigan at concentrations that pose a risk to aquatic and terrestrial organisms
(including humans) within the ecosystem, or that may accumulate to problematic concentrations
-101-
Application of Modeling Tools from the
Green Bay Mass Balance Study
In a pilot mass balance study by EPA and the
Wisconsin Department of Natural Resources, water-
insoluble organic compounds were monitored in Green
Bay, Wisconsin, from 1988 to 1992. The analytical
and modeling tools used in the study may be applied to
the Great Lakes, Lake Champlain, and coastal
estuaries. The Lake Michigan Mass Balance study
is the first full-scale application of this methodology for
toxic pollutants and will serve as the basis of any future
mass balance efforts for persistent, bioaccumulative
chemicals. Data collected for this study are anticipated
in 1997.
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CHAPTER IV
THE GREAT LAKES
FIGURE IV-5
Atmospheric Monitoring Sites in the Great Lakes Region
O IADN Master Stations
A IADN Satellite Stations
Lake Michigan Mass
Balance Station
Sleeping Bear
Dunes
Metro ZooA
Burlington
Muskegon
South Haven
Benton Harbor
Grand Band Rock Point
Port Stanley
. ciair /* -^ Q sturgeon Point
. .. _ Peles-'Is:
Jngjajiapynes
Manitowoc
Milwaukee
Ill - Chicago
in the future and that can serve as examples for other chemicals. In addition, atrazine (under
consideration for addition as a Great Waters pollutant of concern), a commonly used herbicide in
the Great Lakes basin and elsewhere in the United States, is also included in the model. This
herbicide has been reported at elevated concentrations in Lake Erie tributaries, in the open
waters of the Great Lakes, and in the atmosphere over the lakes. The inclusion of this chemical
will provide a model for the more reactive, biodegradable compounds in current use. The model
will be less comprehensive than that for PCBs and trans-nonachlor, because atrazine does not
appreciably bioaccumulate and it will not be analyzed in the food chain.
The chemicals chosen cover a wide range of chemical and physical properties and are
representative of other classes of compounds that could pose water quality problems. This
approach will allow modeling of many other chemicals with limited data. Resource limitations,
quality assurance requirements, and analytical and data handling limitations preclude intensive
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CHAPTER IV
THE GREAT LAKES
monitoring and model calibration for more than the above described target chemicals. While
mass balance modeling will focus on the above chemicals, the determination of loadings and
concentrations for additional contaminants and compounds useful for source apportionment
and deposition modeling will be undertaken as part of the Lake Michigan Monitoring Program.
The Lake Michigan Mass Balance Study includes an atmospheric monitoring component
to address research issues concerning urban and atmospheric deposition and exchange
processes. The data will be used to calculate atmospheric loads to the ecosystem. Within this air
transport component, special studies are being performed to determine whether emissions of
hazardous air pollutants from the urban coastal regions (Chicago, IL, and Gary, IN) contribute
significantly to atmospheric deposition to the adjacent waterbodies. The objectives of these
special studies are to (1) measure wet and dry deposition fluxes of urban contaminants, (2)
determine contributions of urban source categories to measured concentrations and deposition
rates, and (3) assess the extent of air-water exchange of contaminants.
Previous studies indicated that urban emissions have a large impact on atmospheric
concentrations of air toxics and on atmospheric deposition to the Great Lakes. Dry depositional
flux of PCBs from Chicago was shown previously to be three orders of magnitude higher than
that of non-urban areas (Holsen et al. 1991). In addition, the Lake Michigan Urban Air Toxics
Study demonstrated that concentrations of several pollutants were significantly higher in
Chicago urban areas than at less urbanized sites (Keeler 1994). An intensive study was recently
conducted around Chicago to assess the impact of the urban area on atmospheric deposition and
exchange with Lake Michigan, with three land-based monitoring sites around Chicago and one
over-water site on a research vessel approximately five miles off the shore of Chicago. The three
sampling periods that occurred between 1994 and 1995 were designed to provide information to
track atmospheric plumes over and across the lake. Wet deposition, dry deposition, and lake
water were analyzed for semi-volatile compounds (such as PCBs and PAHs) and trace metals
(such as arsenic, mercury, and lead). All samples were taken on the same day to provide
information on air-water exchange of contaminants. Results from this study are expected in
1997, with modeling results expected in 1998. This study is expected to contribute useful
information on urban impact to Lake Michigan, as well as to address process-oriented research
issues and provide data in support of source apportionment and trajectory modeling.
INTEGRATED ATMOSPHERIC DEPOSITION NETWORK (IADN)
As mentioned earlier in this chapter, IADN is a long-term, binational program between
the United States and Canada to assess the magnitude and trends of atmospheric deposition of
target chemicals to the Great Lakes and to determine emission sources wherever possible. The
program addresses the mandate of the Great Waters program and the needs of Annex 15 of the
GLWQA between Canada and the United States. It is designed to (1) provide the necessary
standardized methods, monitoring data, and loadings estimates to assess the relative importance
of atmospheric deposition compared to other inputs, (2) determine temporal trends and
geographic variations in deposition, and (3) ultimately provide information on sources of these
atmospheric pollutants. It is a combination of a surveillance/ monitoring network and a research
program. Its goals are source attribution, process identification, and assessment of atmospheric
impacts on environmental systems. At this time, annual and seasonal averages have been
completed for four years of IADN operation. Data for selected pollutants were presented earlier
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CHAPTER IV
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Compounds Measured in IADN
Highest priority group: PCBs, lindane, PAHs, and
lead. These pollutants were chosen for the first
phase of IADN (1990-1992) to demonstrate the
feasibility and accuracy of sampling and analytical
methods.
Second priority group: Chlorinated pesticides
(such as HCB, DDT/DDE/DDD, trans-nonachlor,
methoxychlor, mirex, dieldrin, aldrin) and trace
metals (such as arsenic, selenium, cadmium, and
mercury). Except for mercury, the sampling and
analysis methods for most of these species had
been implemented by 1993. Mercury monitoring
was added at each IADN site by 1995.
Third priority group: Compounds such as
toxaphene, dioxins/furans, and agrochemicals which
have an important atmospheric component but
require additional methods development to
accurately measure their concentrations in
atmospheric deposition samples.
in this section. Additional details may be
found in Eisenreich and Strachan (1992),
Gatz et al. (1994), and Hoff et al. (1996).
Target compounds were chosen
for IADN based on their potential to
bioaccumulate, their tendency to be
transported atmospherically, and the
availability and efficiency of detection
methods (see sidebar). A major benefit of
IADN is the ability to monitor long-term
atmospheric concentration changes of
such compounds as PCBs and other
chemicals of concern. In the past, such
regional-scale atmospheric data have
been sparse.
It was originally projected that, to
be representative of regional deposition
patterns, the IADN required one "master"
station and several "satellite" stations on
each lake. The master stations are: Eagle
Harbor, MI; Sleeping Bear Dunes, MI; Burnt Island, Ontario; Sturgeon Point, NY; and Pt. Petre,
Ontario (see Figure IV-5). Several satellite sites were later added, including an urban site in
Chicago (see box on next page). The IADN implementation design allows for periodic evaluation
of the existing sites to determine whether other sites are needed.
At each IADN site, concentrations of target chemicals are measured in rain and snow (wet
deposition), airborne particles (dry deposition), and airborne organic vapors. In addition,
precipitation rate, temperature, relative humidity, wind speed and direction, and solar radiation
are measured at each site. IADN results for selected pollutants are presented in Tables IV-1 and
IV-2.
At this time, after five years of operation, many of the sampling and analysis issues of
IADN have been resolved. For example, comparability of sampling and analytical procedures
between jurisdictions was achieved through extensive laboratory intercomparison studies.
However, the uncertainty in the analytical measurement of some compounds is still above the
uncertainty threshold acceptable to most policy makers. Toxic chemicals at extremely low
concentrations in air, such as PCBs and some agricultural chemicals, have the highest
uncertainties in sampling (over 40 percent). Relative standard deviations of air concentrations of
organochlorinated compounds may vary from 60 to 90 percent, due to seasonal and annual
fluctuations in the air, rather than precision of the measurement (Hoff et al. 1996).
Uncertainty in the deposition estimates may result from various factors: (1) general
approximations for estimating deposition; (2) climatic and meteorological variations; (3)
differences in the instrumentation and the scope and objectives of the various jurisdictions and
agencies involved; and (4) estimation of factors used to calculate loadings (e.g., magnitude of
Henry's Law constants, rates of contaminant transfer between the air and water). Despite these
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Urban Influence on Atmospheric Deposition of Contaminants
The primary focus of IADN is to determine regionally representative atmospheric deposition loadings of
toxic chemicals to the Great Lakes. Thus, monitoring stations were positioned to minimize the influence of
local sources and to monitor the atmospheric environment over the lakes as much as possible. This
approach does not directly enable the determination of the role of urban air pollution. Recent research
suggests that deposition of contaminated large particles carried by winds passing over urban areas can
result in substantial inputs of toxic chemicals to the Great Lakes (Falconer et al. 1995; Holsen et al. 1991).
The influence of pollution from the Chicago-northwest Indiana area on water quality in southern Lake
Michigan was studied by Sweet and Basu (1994). The Sleeping Bear Dunes site (in the State of Michigan) is
located one kilometer from the northeastern shore of Lake Michigan and 50 kilometers from the nearest
urban area or major source and, thus, is considered a "remote" site. The first urban site is located 1.5
kilometers from the shore on the campus of the Illinois Institute of Technology, which is near major
expressways and surrounded by commercial and residential areas. The second urban site is located at the
Indiana Dunes National Lakeshore in the vicinity of large steel mills. Particulate concentrations were
measured for target compounds (PCBs, pesticides, and trace metals). Gas concentrations of PCBs and
pesticides were determined, and rain was analyzed only for PCBs.
Results from Sweet and Basu (1994) indicate that, for PCBs, DDT (and its metabolites), dieldrin,
chlordane, and several trace metals (manganese, zinc, chromium, and lead), the measured particulate and
gas concentration values were 10 to 40 times higher in urban areas than at the remote site. For other
pesticides (a-HCH, lindane, HCB) and trace metals (arsenic and selenium), concentrations were nearly the
same at all three sites, indicating these pollutants were well mixed in the air throughout the region (and that
there were probably few local sources).
Though 90 to 99 percent of the PCBs were found in the gas phase, the most toxic PCS congeners were
enriched in the particulate phase (Falconer et al. 1995; Holsen et al. 1991; Sweet and Basu 1994). Thus, dry
deposition may be an important transport mechanism for certain, especially toxic, PCBs to the lakes. Urban
particulate matter also carried high concentrations of trace metals and pesticides, causing dry deposition of
these materials to southern Lake Michigan. Dry deposition of large particles may be especially significant for
Lake Michigan because 200 kilometers of the southwest shoreline are heavily developed. Prevailing
southwest winds carry emissions over the lake where they travel for 100 to 150 kilometers before reaching
land again, allowing a significant portion of the deposition to enter the lake. Finally, the concentration of
PCBs in precipitation is roughly the same in urban and rural sites. The relatively low levels found in urban
precipitation may be due to the fact that many contaminants are collected in clouds or by rain upwind of
polluted areas.
Clearly the influence of urban areas on atmospheric deposition of certain pollutants to the Great Lakes is
substantial, especially in heavily developed areas, such as the southwestern shores of Lake Michigan.
limitations, the reported estimates are the best that are currently available. Also, data on the
concentration of contaminants in the water column for all the Great Lakes have improved
recently with more samples being collected and analyzed.
GREAT LAKES EMISSIONS INVENTORIES
A significant step toward assessing the need to reduce atmospheric loads of hazardous
air pollutants to the Great Lakes is to identify, categorize, and estimate the magnitude of the
pollutant sources. By creating an emissions inventory data base, it is possible to identify the
sources and source categories that contribute most to the total emissions in a given geographic
area, as well as to model emissions transport and deposition. An air emissions inventory is
typically based on mathematical estimates of pollutant releases through the use of emission
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factors (e.g., a number that represents emissions per unit burned, produced, or processed).
These emission factors are derived from actual measurements of the emissions from
representative sources and are derived specifically for one type of process or process equipment.
Emission factors can be used, for example, to estimate both the amount and type of pollutants
being emitted from an air pollution source based upon the quantities of material processed.
The 1986 Great Lakes Governors' Toxic Substances Control Agreement specified
provisions to address atmospheric deposition, including a commitment "to cooperate in
quantifying the loadings of toxic substances originating from all sources, with the purpose of
developing the most environmentally and economically sound control programs." In response
to the governors' direction, the air regulatory agencies in the eight Great Lakes states and the
province of Ontario began to work cooperatively in 1987 to investigate "the development of a
computerized air toxics data base for the purpose of obtaining a better understanding of the
nature and sources of toxic air emissions and their migration, dispersion, and resulting impact
upon the Great Lakes basin." Under the auspices and management of the Great Lakes
Commission (representing the eight Great Lakes states) and with major funding from EPA's
Great Waters program, the Great Lakes states began developing a regional air toxics emissions
inventory. This first regional inventory is scheduled for completion in 1997 and is expected to
compile 1993 emissions data for 49 toxic air pollutants from point and area sources. Emissions
data on toxic air pollutants from mobile sources will be developed in 1997-1998. These
49 pollutants include 10 of the Great Waters pollutants of concern (cadmium, chlordane,
hexachlorobenzene, lead/alkylated lead, mercury, PCBs, PAHs, POMs, TCDD, TCDF). The
continued partnership of the region's air regulatory agencies, now in its eighth year, and the
high level of regional cooperation and coordination exemplifies the commitment to decreasing
toxic deposition into the Great Lakes ecosystem. Yet the inventory must be accompanied by an
ongoing commitment to further quantify, assess, and report on the effects of voluntary and
regulatory reductions of air toxics emissions.
The key to the state's coordinated
efforts is The Air Toxics Emissions Inventory
Protocol for the Great Lakes States, developed
in June 1994 (see sidebar). The Protocol will
be followed by each participating state
ensuring that consistent, agreed-upon best
methodologies are used among all states
when compiling a quality-assured inventory.
This Protocol is an evolving document and
will be updated or revised as needed and
agreed upon by all the Great Lakes states.
The second fundamental component
in developing a toxic air emissions inventory
is the Regional Air Pollutant Inventory
Development System (RAPIDS), a multi-
state pollutant emissions estimation and
storage software system. RAPIDS is a state-
of-the-art, networked, relational data
management and emission estimation
Components of Great Lakes
Emissions Inventory
To date, the Great Lakes States have
developed and tested two fundamental
components of the inventory effort:
1. The Air Toxics Emissions Inventory Protocol
for the Great Lakes - A guide for each state's
efforts to identify sources and estimate
emissions so that the inventory is complete,
accurate, and consistent from state to state.
2. RAPIDS - A client/server relational database
software and data management and emissions
estimation system. It was designed so that the
Great Lakes states may adopt RAPIDS (or
some variant of it) for their state system, and
may also submit their data for incorporation with
the regional RAPIDS data base at EPA.
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system, bridging each state's individual inventory and computer system to the regional RAPIDS
repository of inventory data. RAPIDS' strength is its versatility. States can modify or build upon
it to serve their particular needs. It can be used to estimate both toxic and criteria pollutant
emissions from a single device within a facility or a complex grouping of devices and controls, or
even across geographic areas, ranging in size from one facility to the entire Great Lakes region. It
is designed to run on a personal computer and applies a flexible data model that can be easily
expanded in the future to support multi-media, permitting, monitoring, reporting, and
compliance activities in the states. Emission factors are uploaded from EPA's Factor Information
Retrieval System (FIRE), which contains quality-rated emission factors for both criteria and
hazardous air pollutants.
Using RAPIDS, the Great Lakes states' air regulatory agencies are building a
comprehensive, updatable statewide and regional air toxics inventory for point, area, and (in the
future) mobile sources for the 49 air pollutants. Each of the eight Great Lakes states will be
responsible for compiling, uploading, and validating their state emissions inventory data. It is
anticipated that the inventories will be updated on a one- or two-year basis.
Four states (Illinois, Indiana, Wisconsin, and Michigan) completed a pilot study of major
urban areas along the southwest shore of Lake Michigan in December 1995 using RAPIDS and
the Protocol. The states created an inventory of small point and area source categories in the 12
shoreline counties encompassing Chicago (Illinois), Gary (Indiana), and Milwaukee (Wisconsin)
that contribute the most to the total emissions of the 49 pollutants of concern. These area sources
include gasoline stations, foundries, asphalt and cement plants, and hospitals, among others.
The project was the first rigorous test of the regional Protocol and the RAPIDS software. Total
pollutant emissions from the inventoried sources were collected, but data interpretations and
conclusions were not developed from the results. Instead, the process of compiling the regional
inventory was used as a means of resolving many technical, methodological, and policy-related
issues that impact a multistate, regional toxic air emissions inventory. Furthermore, the pilot
study provided useful information on serious shortcomings that still exist in the regional
emissions estimates and suggested necessary steps that must be made to ensure data quality for
estimating various pollutant groups. The results from this pilot study will also contribute for
better methodology for use in the full eight-state regional inventory.
The level of emissions resolution and the source categories contained in RAPIDS were
planned to meet the modeling needs of Great Lakes air quality researchers. This inventory will
be available for dispersion and deposition models to characterize source, source category, and
geographic contributions, and for mass balance models to characterize media contributions.
Toxics Reduction Efforts in the Great Lakes
In recent years, several programs/activities have developed approaches to reduce
loadings and to mitigate existing contamination. These programs are described below. They
may provide information to further characterize and reduce atmospheric contamination in the
Great Lakes region.
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VIRTUAL ELIMINATION
The Great Lakes Water Quality Agreement of 1978 between the United States and
Canada called for the "virtual elimination" of persistent toxic substances, especially those which
bioaccumulate, from the Great Lakes basin. In keeping with the obligations of the Great Lakes
Water Quality Agreement, two major efforts have occurred: (1) a pilot project sponsored by EPA
to develop the framework to achieve virtual elimination of two pollutants, mercury and PCBs;
and (2) development of the Great Lakes Binational Toxics Strategy (released in April 1997)
between the United States and Canada to set goals to reduce the use and release of selected
pollutants. Many of the recommendations from the pilot project were incorporated into the
Binational Toxics Strategy.
Virtual Elimination Pilot Project. Since 1990, both the United States and Canada have
initiated separate efforts for virtual elimination. EPA began the Virtual Elimination Pilot Project
in 1993, which was designed to answer the following question: "What options exist for
improving the current regulatory and non-regulatory framework to encourage continuing
reductions towards zero in the use, generation, and release of selected toxic substances?" The
aim of the project was to identify barriers to achieving virtual elimination and to develop
strategies to overcome these barriers.
The first iteration or "pilot" portion of the U.S. project focused on the reduction
opportunities for two substances, mercury and PCBs. EPA held a meeting with stakeholders in
the Great Lakes region in 1993 to share information on mercury and PCBs, and to offer
participants the opportunity to make recommendations on ways to reduce the use and release of
each pollutant. Based on the results of this meeting, a draft report was developed by EPA to
identify options to reduce mercury (GLNPO 1995). A draft options paper for the virtual
elimination of PCBs is currently being prepared by EPA. It is expected that this project will
continue with the analyses of classes of substances rather than the use of a chemical-by-chemical
approach.
Mercury presents an unusual challenge to society because of its semi-volatility,
persistence, complex environmental chemistry, and tendency to bioaccumulate in fish. The draft
mercury options paper (GLNPO 1995) proposed regulatory and voluntary measures to prevent
or reduce atmospheric mercury contamination, and introduced the concept of the mercury "life
cycle." A comprehensive approach to virtually eliminating mercury releases was proposed:
• Increase public awareness of mercury problems and mercury-containing items;
• Influence supply of mercury to minimize primary production and manage federal
holdings;
• Minimize use of mercury through pollution prevention and alternative
technologies;
• Reduce uncontrolled releases by encouraging recycling and regulating releases;
and
• Manage disposal of mercury-containing items and mercuric wastes.
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Regulatory and Voluntary Options that may Prevent
or Reduce Atmospheric Mercury Contamination
Pollution Prevention. Mercury use in the United States has substantially declined during the past two
decades. This trend parallels that of western Europe. Ebbing use implies that less mercury will be
included in waste streams reaching incinerators and landfills, or released during production processes.
The decline in use is attributable to both government bans and technological advances that create
environmentally safer products. Mercury has been banned in pesticides (1972-1976 and 1993) and in
paints. The number of U.S. chloralkali facilities using a mercury cell process has declined from 25 during
the early 1970s to 14 in recent years. Minnesota, Wisconsin, and New York restricted mercury content
in batteries, and consequently, national use of mercury in batteries fell from 448 tons during 1988 to 10
tons during 1993. Mercury content in fluorescent bulbs has also declined.
Recycling. A number of users of mercury are taking steps to boost recycling. Various municipal
wastewater treatment plants are working with dental associations to encourage recovery of mercury in
dentist offices so that mercury amalgam does not enter their treatment systems. Some manufacturers
who rely on mercury in instruments are starting or considering take-back programs; EPA and states are
working with several such firms to ensure that liability concerns do not preclude voluntary efforts. A
number of hospitals are diverting mercury-containing wastes from incineration. Several states require
that fluorescent bulbs be recycled (e.g., Florida, Minnesota), because such bulbs are commonly broken
in or en route to landfills, allowing mercury vapors to escape to the atmosphere. While the quantity of
mercury contained in a single bulb is minuscule, the number of discarded bulbs is great.
Management. Pursuant to implementation of the CAA, EPA has proposed performance standards for
municipal and medical waste incinerators. A final rule for municipal waste combustors (new sources with
individual capacity of >250 tons/day) was promulgated in December 1995 (60 Federal Register 65387)
and a proposed rule for medical waste incinerators in June 1996 (61 Federal Register 31736). There are
about 2,400 medical and 180 municipal incinerators across the nation. These sectors are estimated to
generate about one-half of current national emissions of mercury, primarily through combustion of
discarded products that contain mercury. When fully implemented by 2002 through state plans, these
proposed standards hold promise of reducing mercury emissions from these two classes of incinerators
by 95 and 80 percent, respectively. Performance standards will also be evaluated for other sectors that
also emit mercury, including the Portland Cement industry; commercial and industrial boilers; primary
lead smelters; the chloralkali sector; primary copper smelters; sewage sludge incinerators; and lime
manufacturing.
Global Production and Release of Mercury. During recent years, the U.S. government has held a
significant stockpile of mercury on the world commodity market. To dispose of its holding, the
Department of Defense has periodically auctioned mercury. From 1988 through 1993, sales totaled four
million pounds. Sales were suspended in 1994, pending consideration of their environmental impacts.
One positive environmental impact of sales is that they may forestall virgin production of mercury; the
last mercury mines in the United States closed several years ago. Both western Europe and the United
States have become substantial net exporters as their mercury consumption has fallen, whereas world
use may be growing (Lawrence 1994). Because of diminished use of mercury, the United States is
nearly meeting its entire need for mercury through recycling. Much of the mercury sold by the federal
government has been exported. Foreign use and release, due to less stringent controls, can contribute
to global atmospheric contamination which can travel for long distances, and directly contaminate U.S.
surface waters. Suspension of government sales has positioned the United States to seek needed
international cooperation in minimizing mercury releases on a global scale.
The Great Lakes Binational Toxics Strategy. The Canada-United States Strategy for the
Virtual Elimination of Persistent Toxic Substances in the Great Lakes, also known as the Binational
Great Lakes Toxics Strategy, was signed between the two countries on April 7,1997 (U.S. EPA
and Environment Canada 1997). This Binational Strategy was developed jointly by EPA and
Environment Canada, in keeping with the objectives of the 1987 GLWQA. Both Canada and
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United States have domestic virtual elimination strategies but a coordinated strategy is necessary
for the greatest reduction in toxic substances throughout the Basin. Both nations encourage and
support voluntary programs by all stakeholders to reduce the generation, use, and release of
toxic substances to the Great Lakes.
2.
3.
4.
A Four-Step Process Toward
Virtual Elimination
Gather information on generation, uses, and
sources of the pollutant within and outside the
Great Lakes Basin;
Analyze current regulatory and non-regulatory
programs and initiatives that manage or
control the pollutants and identify the gaps in
these regulations that offer opportunities for
reductions;
Develop cost-effective options and provide
recommendations for increasing the pace and
level of reductions; and
Recommend and implement actions to
achieve goal.
The Binational Strategy provides the
framework to achieve quantifiable goals in a
specified time frame (1997 to 2006) for
targeted persistent toxic substances,
especially those which bioaccumulate.
Flexibility is provided in the Strategy to allow
for the revision of targets, time frames, and
the list of pollutants. All actions and
activities, both regulatory and nonregulatory,
will be considered to help speed reductions.
The Strategy also recommends that goals be
accomplished through a four-step process
(see sidebar). The pollutants identified in the
Strategy fall into two lists. The Level I
substances represent an immediate priority
and are targeted for reduction and eventual
virtual elimination through pollution
prevention and other incentive-based
actions. These pollutants are aldrin/dieldrin,
benzo(a)pyrene, chlordane, DDT/DDE/DDE, hexachlorobenzene, alkyl lead, mercury and
mercury compounds, mirex, octachlorostyrene, PCBs, dioxins/furans, and toxaphene. For
pollutants that are considered Level II substances, the governments encourage stakeholders to
undertake pollution prevention activities to reduce levels in the environment of those substances
nominated jointly by both countries, and to conform with the laws and policies of each country,
including pollution prevention, with respect to those substances nominated by only one country,
until and unless these pollutants are placed on the Level I list. The Level II pollutants are
cadmium and cadmium compounds, 1,4-dichlorobenzene, 3,3'-dichlorobenzidine, dinitropyrene,
endrin, heptachlor (and heptachlor epoxide), hexachlorobutadiene (and hexachloro-1,3-
butadiene), hexachlorocyclohexane, 4,4'-methylenebis(2-chloroaniline), PAHs,
pentachlorobenzene, pentachlorophenol, tetrachlorobenzene (1,2,3,4- and 1,2,4,5-), and tributyl
tin.
Both the United States and Canada have set "challenge" goals to achieve reductions
through implementation of voluntary efforts and regulatory actions. One of these challenges is
the commitment of these 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. Efforts will be made to work within the existing international framework to reduce
releases of such pollutants from remaining long-range sources. Activities by EPA and
Environment Canada to meet this particular challenge include:
• Coordinate efforts to identify sources in order to better define and coordinate
emission control programs;
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• Maintain atmospheric deposition monitoring stations to detect deposition and
transport of toxic substances;
• Continue research on atmospheric science of toxic pollutants to refine and to
improve existing source, receptor, and deposition models, as well as improve
integration of existing air toxic monitoring networks and data management
systems to track deposition of contaminants within the Great Lakes; and
• Conduct an assessment of long-range transport of persistent toxic pollutants from
worldwide sources
In addition to these coordinated binational efforts, Environment Canada will also demonstrate
alternative processes to lessen emissions from five predominant sources by 2001 and complete
inventories of 10 selected air pollution sources to support assessment of environmental impacts
of air toxics by 1999.
Besides the above challenge, the Strategy includes several specific reduction goals or chal-
lenges for the Level I pollutants (Table IV-3). For the United States, the baseline from which these
reductions will be measured will be the most recent and appropriate inventory (e.g., mercury will
be based on estimated emissions during the early 1990s). Canada plans to use their 1988 emissions
inventory.
Two additional challenges from the Strategy are: (1) complete or be well advanced in
remediation of priority sites with contaminated bottom sediments in the Great Lakes Basin by
2006; and (2) promote pollution prevention and sound management of Level II substances, to
reduce levels in the environment. The Binational Strategy is intended to fill in the gaps that exist
where ongoing programs or emerging initiatives do not address toxic releases, to provide a
context of basinwide goals for localized actions, and to provide "out of basin" support to
programs such as LaMPs.
LAKEWIDE MANAGEMENT PLANS (LAMPs)
In Article VI, Annex 2 of the GLWQA, the U.S. and Canadian governments agreed to
develop and implement LaMPs for each of the five Great Lakes. The purpose of the LaMPs is to
document an approach to reducing input of critical pollutants to the Great Lakes and restoring
and maintaining Great Lakes integrity. LaMPs are management tools designed to (1) integrate
federal, state, provincial, and local programs to reduce loadings of toxic substances from both
point and nonpoint sources; (2) assess whether these programs will ensure attainment of water
quality standards and designated beneficial uses; and (3) recommend any media-specific
program actions or enhancements to reduce toxic loadings in waters currently not attaining
water quality standards and/or designated beneficial uses. Unlike the other four Lakes, Lake
Michigan lies entirely within the boundaries of the United States and therefore, the Lake
Michigan LaMP has been developed solely by U.S. federal and state agencies with input from a
public forum. The development of this program, as well as the deadlines established for the
completion of the program, is mandated under section 118 of the CWA. In addition, as noted in
Chapter I, section 112(m) of the CAA requires that EPA, in cooperation with NOAA, monitor the
Great Lakes, investigate atmospheric deposition rates and pollutant sources, improve monitoring
methods, and determine the relative contribution of atmospheric pollutants to the total pollution
loadings to the Great Lakes and other Great Waters.
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TABLE IV-3
Specific Pollutant Reduction Goals Under the Great Lakes Binational Toxics Strategy'
Level I
Substances
United States Challenge
Canadian Challenge
Aldrin/Dieldrin,
Chlordane, DDT,
Toxaphene,
Mi rex,
Octachlorostyrene
Confirm by 1998 that there is no longer use
or release from sources that enter Great
Lakes Basin. If ongoing long-range sources
from outside of U.S. are confirmed, use
existing international frameworks to reduce
or phase out releases.
Report by 1997 that there is no longer use,
generation, or release from Ontario sources
that enter Great Lakes Basin. If ongoing
long-range sources outside of Canada are
confirmed, use existing international
frameworks to reduce or phase out releases.
Alkyl lead
Confirm by 1998, there is no longer use in
automotive gasoline; support and encourage
stakeholder efforts to reduce releases from
other sources.
Seek by 2000, 90 percent reduction in use,
generation, or release.
PCBs
Seek by 2006, a 90 percent reduction
nationally of high level PCBs (>500 ppm) in
electrical equipment; ensure all PCBs retired
from use are properly managed and
disposed of to prevent accidental releases
within or to the Great Lakes Basin.
Seek by 2000, a 90 percent reduction
nationally of high-level PCBs (>1 percent
PCBs) that were once, or are currently, in
service and accelerate destruction of stored
high-level PCS wastes that may enter the
Great Lakes Basin.
Mercury"
Seek by 2006, a 50 percent reduction
nationally in deliberate use of mercury and a
50 percent reduction in release from sources
resulting from human activity.0
Seek by 2000, a 90 percent reduction
nationally in releases of mercury, or where
warranted the use of mercury, from polluting
sources resulting from human activity in the
Great Lakes Basin.
Dioxins/Furans
Seek by 2006, a 75 percent reduction in total
releases of dioxins/furans (2,3,7,8-TCDD
toxicity equivalents) from sources resulting
from human activity.0
Seek by 2000, a 90 percent reduction in
releases of dioxins/furans (focus on 2,3,7,8-
substitute congeners) from sources resulting
from human activity in Great Lakes Basin.
Benzo(a)pyrene,
HCB
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.
Seek by 2000, a 90 percent reduction in
releases from sources resulting from human
activity in the Great Lakes Basin.
a _ . .. , , ... ,., ... nted in The Great Lakes Binational Toxics Strategy
Detailed descriptions of these challenges are prese
(U.S. EPA and Environment Canada 1997).
b Mercury challenges are considered interim reduction targets for mercury and, in consultation with stakeholders,
will be revised if warranted, following completion of EPA's Mercury Study Report to Congress (U.S. challenge) and
1997 Canada-Ontario Agreement Respecting the Great Lakes Basin Ecosystem (Canadian challenge).
0 The release challenge applies to the aggregate of releases to the air nationwide and of releases to the water
within the Great Lakes Basin.
A LaMP is a dynamic, action-oriented process encompassing a number of components.
These include an evaluation of beneficial use impairments and pollutants contributing to those
impairments; a summary of sources and loads of these critical pollutants; identification of
ongoing prevention, control, and remediation actions, as well as additional efforts needed to
reduce pollutant loads and to restore beneficial uses; and monitoring activities to evaluate the
effectiveness of program actions. This approach for developing and implementing LaMPs is an
evolutionary and iterative process for identifying and reducing critical pollutants. Public
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participation and cooperation with states and local governments is a key component to the
LaMP development process.
LaMPs are in various stages
of development for each of the Great
Lakes (see sidebar). Not all of the
Lakes have LaMPs published in the
Federal Register; however, com-
mitments have been made by key
stakeholders in the respective basins
to pursue toxics reduction. Actions
are being taken to achieve this goal.
Each LaMP addresses a different list
of critical pollutants, but some
common ones are mercury, PCBs,
hexachlorobenzene, dioxins, furans,
chlordane, DDT and metabolites,
and dieldrin (all of which are Great
Waters pollutants of concern).
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 for public review (1996)
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)
Several activities have been initiated through LaMPs:
4 In the Lake Michigan basin, agricultural "clean sweeps" to properly collect and dispose of
unused pesticides have been conducted in Indiana, Michigan, and Wisconsin. Also, a
variety of pollution prevention and technical assistance projects have taken place in
Milwaukee, Chicago, and western Michigan.
4 In most lake basins, tributary and atmospheric deposition monitoring is occurring. The
Lake Michigan LaMP is utilizing the information generated from the Lake Michigan Mass
Balance Study (described earlier in the section) to identify and reduce loadings as data
become available.
4 The Lake Superior LaMP was initiated as a component of the binational efforts to restore
and protect Lake Superior. One of the goals of the LaMP is to achieve zero discharge and
emission of persistent toxic pollutants through its Zero Discharge Demonstration Project.
Another effort of the Lake Superior LaMP is an extensive pollution prevention outreach
and education program developed for mercury. Among the activities are battery collec-
tion, energy efficiency, and product takeback programs. For example, Honeywell, Inc.,
the largest manufacturer of mercury thermostats used in regulating heating in the home,
has instituted a thermostat takeback program in which the company recycles the mercury.
The LaMPs often provide the needed coordination and oversight for many such projects
being implemented all over the Great Lakes Basin.
THE GREAT LAKES WATER QUALITY (GLWQ) GUIDANCE
Another notable toxics reduction effort was the GLWQ Guidance (U.S. EPA 1995a). It is
the culmination of a six-year cooperative effort that included participation by the eight Great
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CHAPTER IV
THE GREAT LAKES
Lakes states, the environmental community, academia, industry, municipalities, and EPA's
regional and national offices, and stems from the Great Lakes Water Quality Initiative, which
began when the states of the Great Lakes Region recognized the important feature of the Great
Lakes ecosystem to accumulate persistent pollutants. The guidance is not only designed to
address existing problems, but also to prevent emerging and potential problems posed by addi-
tional chemicals in the future, which may damage the overall health of the Great Lakes system.
The guidance includes criteria for the protection of human life, wildlife, and aquatic life, taking
into account the ability of many pollutants to biomagnify. Antidegradation requirements assure
that current water quality will not be diminished. The guidance also outlines procedures to ensure
consistent implementation and appropriate flexibility for long-term protection of the Great Lakes.
The GLWQ Guidance promotes the use of pollutant minimization plans to stop pollution
before it enters the environment. Reducing pollution at its source is the most effective way of
protecting public health and the environment, and is often more economical than cleaning up
after a pollutant is released.
The water quality criteria in the GLWQ Guidance apply to all of the waters in the Great
Lakes system, regardless of the source of pollution. Pollutants enter the Great Lakes from the air,
stirred-up bottom sediments, urban and agricultural runoff, hazardous waste and Superfund
sites, spills, and industrial and municipal wastewater discharges. Although the implementation
procedures of the guidance apply mostly to industrial and municipal water discharges, a state
may find it is more effective (or cost-effective) to improve water quality by reducing air emissions
or cleaning up contaminated sediments, and may choose not to impose additional requirements
on wastewater dischargers.
GREAT LAKES REMEDIAL ACTION PLANS
The 1978 GLWQA, along with the 1987 amendments, established guidelines for restoring
the quality of the Great Lakes. As a response to this measure, geographical "problem areas" or
Areas of Concern (AOCs) were identified in the Great Lakes where GLWQA objectives had been
exceeded and such exceedance had caused, or was likely to cause, impairment of beneficial use
or the area's ability to support aquatic life. The defined AOCs include rivers, connecting
channels, harbors, and embayments of the Great Lakes, with the U.S. states and Canadian
provinces responsible for remediating these areas. The Water Quality Board (WQB) of the IJC
determines the AOCs, but the specific geographical boundaries of the AOCs are set by the states
and/or provincial governments. Currently, there are 43 AOCs; 12 are under Canadian
jurisdiction, 26 under U.S. jurisdiction, and five under jurisdiction of both countries. The sources
of contamination have usually been water discharges from point and non-point sources.
In order to provide more uniform guidance on how to remediate the AOCs, Remedial
Action Plans (RAPs) were introduced in 1985. In 1994, eight U.S. states were involved in the RAP
process: Indiana, Illinois, Minnesota and Pennsylvania (1 AOC each), Ohio (4 AOCs), Wisconsin
(5 AOCs), New York (6 AOCs), and Michigan (14 AOCs). Currently, for most AOCs, the problem
definition stage of the RAP process has been addressed and the planning and implementation
stages are to be initiated. One of the major problems facing the AOCs today is toxic contamina-
tion of the sediments. All of the U.S. AOCs have impaired beneficial uses attributable to
contaminated sediments (U.S. EPA and Environment Canada 1994). As a result, sediment
remediation is a key component of RAP remediation.
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CHAPTER IV
THE GREAT LAKES
The progress of AOC remediation is presented in an EPA report, Progress in the Great Lakes
Remedial Action Plans: Implementing the Ecosystem Approach in the Great Lakes Areas of Concern (U.S.
EPA and Environment Canada 1994). This report provides an update for each AOC in the Great
Lakes and summarizes the major barriers to and benefits of the RAP process. It concludes that a
comprehensive decision-making process that leads to commitment for action is an essential
aspect of implementing an ecosystem approach, as required in a RAP. Great Lakes federal, state,
and provincial governments have provided leadership and resources for development and
implementation of RAPs. Through government and community-based partnerships, RAPs are
being developed to be a coordinated, multi-stakeholder response to restoring impaired beneficial
uses in AOCs.
SOME ADDITIONAL ACTIONS RELATED TO Toxic CONTAMINATION AND REDUCTION
In addition to activities described above, many pollutant-specific efforts provide
significant information on atmospheric contamination in the Great Lakes. For example, EPA
developed standards for municipal waste combustors (excludes new sources with individual
capacity of <250 tons/year) (60 Federal Register 65387) and proposed standards for medical waste
incinerators (61 Federal Register 31736) which will, when implemented by 2002, provide about a 70
ton reduction in mercury emissions, or 35 percent of current total U.S. emissions, based on 1990
emissions estimates. Implementation of other Maximum Available Control Technology (MACT)
standards, including those proposed in 1996 for hazardous waste combustors, offer the
probability of further mercury emission reductions in the future.
For toxaphene, many issues remain about its sources and continuing presence in the
Great Lakes. EPA held a research workshop on March 27-29,1996, with scientists to assess these
concerns (U.S. EPA 1996c). Based on the meeting, the following actions were recommended to
maintain progress toward resolving several questions concerning concentrations and trends
(spatial and temporal) in various Great Lakes media and the sources of toxaphene in the Great
Lakes:
• Measure concentration gradient of toxaphene across air-water interface and link
with atmospheric source profile to establish seasonal and annual fluxes to and
from Lakes Superior and Michigan, as well as correlative measurements in other
Great lakes to permit spatial comparisons;
• Collect additional sediment cores in Lakes Superior and Michigan to determine
concentrations, accumulation rates, and inventories to help establish past
dynamics of toxaphene and assist in efforts to forecast future conditions in the
Great Lakes;
• Quantify aquatic food web dynamics to establish how food web influences spatial
and temporal variations in toxaphene concentrations in biota.
• Measure physical-chemical properties of toxaphene homologs and congeners.
Besides providing information on sediment deposition and cycling of toxaphene in the Great
Lakes, it is anticipated that results from these recommendations would provide a more firm
technical basis upon which to explore the need for and extent of appropriate management actions.
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CHAPTER IV
THE GREAT LAKES
Another major binational effort to broadly address Great Lakes issues is the State of the
Lakes Ecosystem Conference (SOLEC) organized by the governments of the United States and
Canada. In the first SOLEC in 1994, a report (and five background papers) was released on the
current condition of the Great Lakes
(Environment Canada and U.S. EPA 1995).
The report addressed the entire Great Lakes
system in terms of ecological and human
health, and the stressors which affect it. The
six areas of discussion were human health;
aquatic community health; aquatic habitat;
toxic contaminants; nutrients; and the
.,,. , ,. ,,., , SOLEC was initiated and held in October 1994.
economy. Although the report did not The second meeting of SOLEC was he|d jn
Windsor, Ontario, on November 6-8, 1996.
SOLEC is viewed as part of a process of sharing
information needed to make well informed
.,, . ,1 ,-, , T , , rp, C/->T rr- decisions that affect the ecosystem of the Great
within the Great Lakes system. The SOLEC Lakes |t jg attended by manaygers and Qther
describe or evaluate pollution control or
natural resource management programs, it
did focus on environmental conditions
State of the Lakes Ecosystem Conference
(SOLEC)
As part of the continuing response by the
governments of the United States and Canada to
the binational Great Lakes Water Agreement,
decision makers from the private sector, and
government and non-government environmental
organizations.
report indicated that there has been
considerable improvement in all the Great
Lakes compared to 30 years ago, although
serious losses in habitat for native plants and
animals continues. Nutrient and toxic
contaminant concentrations appear to be decreasing, although bioaccumulative pollutants still
cause problems. The report presented a "mixed picture" of the current conditions of the Great
Lakes and challenges managers and decision makers throughout the basin to obtain adequate
information, deal with subtle effects of long-term exposure to low levels of toxic contaminants,
protect biodiversity, restore habitat for native plants and animals, connect decisions with
ecosystem results, and attain sustainability.
Building on the findings of the first SOLEC, the 1996 SOLEC (Environment Canada and
U.S. EPA 1996) focused on nearshore areas of the Great Lakes basin (i.e., warm and shallow
waters, coastal wetlands). These areas represent the most diverse and productive parts of the
Great Lakes ecosystem, and provide support for most intense human activity and subsequently,
are subjected to greatest stress. Key themes from the conference were immediate actions;
local/community level involvement; development of common ecosystem health indicators to
measure progress; essentiality of cooperation and partnership due to complexity of issues and
development of new ideas; approaches that recognize long-term perspective; and focus on
prevention and preservation. The Great Waters program will benefit from many aspects of
SOLEC, such as the information gathered on the impact of air pollutants on human health and
ecological effects and the promotion of pollution prevention measures.
Addressing Data Gaps/Future Needs
Considerable progress has been made in the recent past in characterizing and reducing
toxic pollution in the Great Lakes. The programs presented above and summarized in Table IV-
4 provide an overview of some notable and recent activities by the United States, as well as
Canada, to respond to concerns related to atmospheric pollution in the Great Lakes. Some of
these measures include identifying emission sources; characterizing contamination from
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CHAPTER IV
THE GREAT LAKES
TABLE IV-4
Summary of Some Major Programs to Address Atmospheric Contamination in the Great Lakes
Data Collection/Research Projects
Lake Michigan Monitoring
Program/Lake Michigan Mass
Balance Study
Integrated Atmospheric
Deposition Network (IADN)
Great Lakes Emissions
Inventories
Scientific base for future load reduction effort at all
government levels. Mass balance study addresses CAA
section 112(m) through coordinated effort to quantify and
understand loadings, transport, and fate of selected HAPs.
Also to provide a validated method to estimate loading for
other waterbodies.
Binational monitoring network and research program to
determine magnitude and trends of atmospheric deposition
for the region.
Inventory of sources and source category emissions in
Great Lakes region, with a multi-state data base (RAPIDS).
Toxics Reduction Efforts
Virtual Elimination Pilot Program/
Great Lakes Binational Toxics
Strategy
Lakewide Management Plan
(LaMP)
Great Lakes Water Quality
(GLWQ) Guidance
Remedial Action Plans for Great
Lakes Areas of Concern (AOCs)
Regulatory and non-regulatory efforts to encourage
reduction in use and release of bioaccumulative pollutants in
Great Lakes.
Management tool to document approach to decrease
pollutant input to each of the Great Lakes.
Promotion of pollution minimization plans to stop pollution
before it reaches the environment, and consistent standards
to protect human health, wildlife, and aquatic life.
Action-planning process for implementing remedial and
preventive actions to restore impaired beneficial uses of
specific areas.
pollutants; developing and implementing voluntary and regulatory measures; and developing
guidance for evaluating levels of risk of pollutant contamination. These programs have usually
involved coordination among various federal, state, and/or local agencies. Though each program
is designed to address specific goals, many of these programs coordinate their efforts to ensure
that results are not duplicated. For example, the Binational Virtual Elimination Strategy was
developed to achieve virtual elimination of persistent toxic pollutants in the Great Lakes, but it
also supports and builds upon ongoing processes in the LaMPs, such as the Zero Discharge
Demonstration Project through the Lake Superior LaMP. Furthermore, the Great Lakes
Emissions Inventories will eventually provide information for determining whether the
reduction goals set in the Great Lakes Binational Toxics Strategy have been met. The IADN will
monitor whether pollutant levels are actually decreasing.
The Great Lakes programs described in this chapter also complement the Great Waters
program in assessing and identifying the extent of atmospheric contamination of hazardous air
pollutants to the Great Lakes. Further coordinated progress is needed to improve knowledge
and understanding of pollutant contamination, as well as to increase public awareness. In
addition to the continuation of the current programs/activities, some high priority efforts for the
Great Lakes basin include:
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CHAPTER IV
THE GREAT LAKES
4 Improvement in research and monitoring techniques to reduce uncertainties in loading
calculations (such as those for the IADN) and therefore, result in better estimates of
atmospheric pollutant levels and deposition;
4 Improvement in dispersion and deposition models currently being developed to link
emission inventory information to atmospheric loadings of Great Lakes pollutants at the
water's surface;
4 After Lake Michigan Mass Balance data have been analyzed, application of results and
modeling tools from the study to the development of a general mass balance model for
other hazardous air pollutants;
4 Increase in efforts to identify local and long-range sources of Great Lakes pollutants
through various source apportionment modeling and emissions inventories, such as in
the RAPIDS data base; and
4 Continuation of efforts to develop and implement strategies and recommendations to
reduce use, generation, and release of pollutants affecting the Great Lakes, particularly
through binational efforts such as the reduction challenges proposed under the
Binational Virtual Elimination Strategy.
As more information is gathered on the characterization and reduction of atmospheric
deposition of toxic pollutants to the Great Lakes, the results of these efforts, as well as the tools
used, may be applied to other waterbodies, such as Lake Champlain.
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CHAPTER IV
LAKE CHAMPLAIN
IV.B Lake Champlain
Located around the northernmost borders of the states of New York and Vermont and
the southern border of the province of Quebec, Lake Champlain is one of the largest freshwater
lakes in the United States, with 1,127 km2 of surface water, over 70 islands, and 945 km of
shoreline (see Figure IV-6). It flows north from Whitehall, New York, almost 193 km across the
U.S.-Canadian border to its outlet at the Richelieu River in Quebec, where it joins the St.
Lawrence River. Lake Champlain is unique because of its narrow width (19 km at its widest
point), great depth (over 122 meters in some parts), and large size of the watershed relative to the
lake surface.
The Lake Champlain Basin, composed of the entire watershed or drainage area, spans
from the Adirondack Mountains in the west to the Green Mountains in the east, and from the
Taconic Mountains in the southeast to the St. Lawrence Valley in the north (Figure IV-6). The
total area of the Basin is 21,326 km2, of which 56 percent is in Vermont, 37 percent is in New
York, and 7 percent is in Quebec. The Basin is characterized by an 18:1 ratio of watershed to lake
surface area, indicating that the lake represents only about 5 percent of the total basin area.
Approximately 89 percent of the Basin is categorized as forest and agricultural land.
By the end of 1994, approximately
645,000 people resided in the Lake
Champlain Basin, with the population
increasing each year by about 1.2 percent
(LCBP 1994). Most of the region is classified
as rural, with only Burlington, Vermont,
recognized as a metropolitan area (1990
population of 52,000). The Lake Champlain
Basin has traditionally had a rural resource-
based economy, including agriculture,
renewable natural resources (e.g., timber,
fish, maple syrup), and non-renewable
natural resources (e.g., iron ore, marble,
gravel). In recent years, the economy has
diversified into other activities, but is still
dependent on the natural resources (see
sidebar).
Lake Champlain, unlike many other
lakes that tend to be more evenly mixed, is
made up of five distinct areas or lake segments, each with different physical and chemical
characteristics (Figure IV-6). In these lake "divisions," pollutants may accumulate in shallow
areas or bays where flushing and water circulation are reduced, and may be deposited at the
mouths of rivers where runoff carrying sediment and other pollutants from the watershed is
discharged. Human activities also concentrate in many of these areas of the lake, increasing the
potential for contamination and exposure.
Economic Highlights of
Lake Champlain Basin
• Twenty-five percent of the workforce is
employed in natural resource-related activities
(e.g., agriculture, mining, forestry).
• Resources of the Lake are a major reason
why many Basin residents reside in this
region.
• Tourism represents a significant economic
factor for the region, generating $2.2 billion in
1990, of which 40 percent were Lake related
(e.g., marina, white-water rafting). Part of
tourism income comes from recreational
activities, including $81 million per year from
fishing industry (in 1991) and $50 million per
year from bird and wildlife viewing (in 1990).
Sources: LCBP 1994, 1996.
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CHAPTER IV
LAKE CHAMPLAIN
FIGURE IV-6
Lake Champlain Basin
very shallow,
with relatively
warm water
and restricted
circulation
largest portion (81%)
of lake, containing
deepest, coldest
water and retaining
water the longest
(about 3 years)
more shallow
than main lake,
the water flowing
south from
Missisquoi and
north from
Mallets Bay
narrow and
shallow, with
water retained
in this segment
for less than
2 years
Canada
United States
Inland Sea
Malletts Bay
smallest portion
of lake, with
most restricted
circulation due
to causeways
built to the
north and west
New York i Vermont
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CHAPTER IV
LAKE CHAMPLAIN
An understanding of the hydrodynamics of Lake Champlain is essential to predicting
how and where pollutants are transported, and where they will end up in the lake. A simplified
three-dimensional hydrodynamic transport model, being developed with funding by the Lake
Champlain Basin Program (LCBP), will be used as a management tool to determine potential
effects of pollutant inputs and other changes to the waterbody (LCBP 1994).
Characterizing Toxic Contaminants in Lake Champlain
Levels of toxic contamination in Lake Champlain are low compared to the Great Lakes;
however, concerns for protecting the public health still exist. Fish consumption advisories for
two Great Waters pollutants (mercury and PCBs) are currently in effect in both New York and
Vermont for fish from Lake Champlain (see Appendix B) (LCBP 1994). Testing of lake bottom
sediment near the urbanized sites along the Lake shows pollutants levels that may be of concern
and indicates potential risks to aquatic life (see Section II.B). Because of these findings, as well as
exceedances of water quality standards set by EPA, NOAA, and the province of Ontario, LCBP
gives highest priority to these two pollutants.
The contribution of air deposition as
a source of loadings for pollutants, such as
metals and organic compounds, is of
concern for Lake Champlain and the Basin,
and has been the subject of recent studies.
Although emissions of toxic pollutants
within the Basin are considered low
because of the few industries and utilities in
Regional/ Smelters (Quebec)
Atmospheric Sources of Toxic
Contamination in Lake Champlain
Local Mobile emissions
Residential energy consumption
(e.g., wood burning)
Waste incinerators
Long-distance Utilities (midwestern United States)
the local area, high levels of pollutants may
reach the Lake from more distant sources
(LCBP 1994,1996). Data have been limited
regarding atmospheric sources, or the movement of pollutants from the atmosphere to the Lake
directly or through the watershed.
A 1990/1991 air monitoring study measured the concentration of toxic metals at four sites
in the Lake Champlain Basin (Whiteface Mountain, NY; Willisboro Bay, NY; Burlington, VT; and
Under hill, VT) (LCBP 1994). Preliminary data revealed elevated levels of zinc in the air
surrounding Burlington, possibly due to refuse incineration, tire wear, and industries. There
were also periodic increases in arsenic levels at these and other sites across the Northeast. The
source of these arsenic concentrations in the air is believed to be a smelter in Quebec (LCBP
1994). Mercury, lead, and cadmium compounds were also measured in this study; however,
there was no indication that the concentrations for these Great Waters pollutants of concern
were of concern at the monitoring sites.
The following subsection focuses on currently ongoing mercury research to determine
atmospheric deposition to the Lake Champlain Basin. Information on atmospheric deposition of
the other high priority pollutant to the basin, PCBs, is lacking at this time.
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ATMOSPHERIC DEPOSITION OF MERCURY IN THE LAKE CHAMPLAIN BASIN
Mercury burden in Lake Champlain is evidenced by fish consumption advisories. Direct
discharges of mercury are quite limited which has led to concerns that the atmosphere may be
the major route of mercury to the lake. Recent studies supported by NOAA and EPA's Great
Waters program have investigated the deposition of atmospheric mercury in the Lake
Champlain Basin (Burke et al. 1995; Scherbatskoy et al. 1997). The air monitoring data collected
from these efforts should provide an initial framework for a more comprehensive analysis of
mercury cycling (i.e., deposition, transport, transformation, and accumulation) in the region, and
beyond. There is currently no information that compares the estimated amount of mercury
entering the lake via water (e.g., runoff) with the amount deposited from the air.
Atmospheric mercury concentration and deposition in Lake Champlain was investigated
at a location just east of the Lake in Underhill, Vermont, between 1992 and 1994 (Scherbatskoy et
al. 1997). The atmospheric concentration of mercury was measured as gaseous and particulate
phases in the ambient air and in precipitation (snow, rain) (see sidebar). Findings on the
atmospheric mercury levels near Lake Champlain are presented below and in Figure IV-7:
Atmospheric gaseous mercury
concentration. Average gaseous
concentration for 1993 was
1.94 ng mercury/m3 (comparable to
other sites near the Great Lakes),
staying relatively constant
throughout the year (Table IV-5).
Concentrations are typically two „ .. , . ... ,. . , ,,.
J r J Particulate Phase Mercury, consists of fine
particles that are not readily deposited from the
atmosphere; bound Hg+2isthe predominant form
orders of magnitude (100 times)
higher than particulate mercury.
and exists as the nucleus in dust particles.
Average particulate phase mercury
Principal Phases of Atmospheric Mercury
Gaseous (Vapor) Phase Mercury, consists
primarily of elemental mercury (Hg°; predominant
form in the atmosphere), although divalent
mercury (Hg+2) may also be present; Hg+2 is
deposited more rapidly than elemental mercury.
Mercury in Precipitation, consists of mercury
either as dissolved gas or bound to fine particles;
primarily particulate Hg that has been taken up
by rain droplets.
concentration. Unlike the gaseous
phase, particulate phase mercury in
the air exhibited seasonal variability,
with levels higher in winter than in
summer (Figure IV-7). The source of
the increased particulate mercury concentration in the winter has not been identified, but
preliminary meteorological analysis suggests that a more regional influence is important
in the transport of particulate phase mercury in the winter, due to higher average wind
speeds and colder temperatures during this season. It also is suggested that colder
temperatures in the winter may favor condensation of gas onto particles, increasing
mercury particulate concentration in the atmosphere (Scherbatskoy et al. 1997).
Furthermore, daily mercury concentrations did not fluctuate significantly, as would be
expected for strong local sources.
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FIGURE IV-7
Atmospheric Mercury in Lake Champlain Basin"
Mercury Vaper Concentration:
(consistent throughout the year)
1.94 ng/m3
Mercury in Precipitation: 3.3 ng/L
(11 ng/L summer, 4.4 ng/L winter)
Articulate Mercury Concentration: 0.011 ng/m3
(0.009 ng/m3 winter; 0.016 ng/m5 summer}
Total Mercury Deposition: 14.97 ug/m2/yr
Wet Deposition: 9.27 [jg/mVyr
Dry Deposition: 5.7 [jg/rrf/yr
Total Mercury Loading:
(to entire basin)
kg/yr
a Values are annual average, unless otherwise specified.
Source: Scherbatskoy et al. 1997
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CHAPTER IV
LAKE CHAMPLAIN
TABLE IV-5
Comparison of Mean Total Atmospheric Mercury Concentrations'
(Gaseous and Particulate Phases and in Precipitation)
Location
Lake Champlain
Northern Michigan13
Southern Michigan13
Northern Wisconsin0
Northern Wisconsin"1
Gaseous Phase
(ng/m3)
1.94 ±0.5
NA
NA
1.57 ±0.4
1.8 ±0.4
Particulate
Phase
(ng/m3)
0.011 ±0.007
0.011
0.022
0.02 ± 0.02
0.01 ± 0.02
Precipitation (ng/L)
(volume-weighted)
8. 3 ±5.2
7. 9 ±7.4
10.2 ±9. 8
10. 5 ±4. 8
6. 7 ±5.6
NA = Not Available
a Data are means for varying years and periods; different sampling methods for the studies.
Gaseous and particulate phase mercury data represent total dry deposition.
b Hoyer et al. 1995; Keeler et al. 1995
c Fitzgerald et al. 1991
d Lamborg et al. 1995
Adapted from Scherbatskoy et al. (1997).
Average mercury concentration in precipitation. Levels appeared to be typically higher in the
summer than the winter. Partial data from 1994 suggest that the pattern observed in 1993
is typical for this area. Based on meteorological data, precipitation events with the
highest mercury levels during the year were associated with regional transport from the
south or west; transport from the west occurred only during the summer months (Burke
et al. 1995). The observed mercury levels are low; studies have reported mercury
concentration in precipitation generally less than 100 ng/L in areas not directly influenced
by emission sources. The type of mercury in precipitation was not quantitatively
determined (Scherbatskoy et al. 1997); however, other studies of precipitation found
mercury to be in the inorganic (Hg+2) form, probably as mercuric chloride (Burke et al.
1995), with only 2 to 10 percent in the organic (methyl) form (Bloom and Watras 1989;
Driscoll et al. 1994).
Yearly deposition of mercury. Deposition to the entire Lake Champlain Basin, not just to
surface water, was estimated from precipitation (wet deposition) and dry deposition
data. Total annual mercury deposition was not very different from that observed at
other U.S. locations (Table IV-6). Dry deposition was calculated by using the same
monthly proportion of gas deposition to gas concentration reported in Lindberg et al.
(1992). Deposition of particulate phase mercury was not a significant source of
atmospheric mercury loadings when compared to deposition of mercury in
precipitation and from the gas phase. The atmospheric mercury particulate
concentration in the area (0.011 ng/m3) was much lower than the gas concentration
(1.9 ng/m3); therefore, the estimate of mercury dry deposition was based solely on
gaseous mercury (which may be an underestimate of deposition to some extent). As
shown in Figure IV-7, the annual dry deposition is 5.7 jug mercury/m2 (with levels
higher in the summer than the winter). Mercury deposition in precipitation for 1993
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CHAPTER IV
LAKE CHAMPLAIN
TABLE IV-6
Comparison of Annual Mercury Deposition Estimates'
Location
Lake Champlain basinb
Michigan0
Little Rock Lake, Wld
Minnesota and Northern Wisconsin8
Estimated Wet
Deposition
(ug/m2/year)
9.27
5.5-13.0
4.5 ± 2 from rain
2.3 ± 0.3 from snow
NA
Estimated Dry
Deposition
(ug/m2/year)
5.7
NA
3.5 ±3
NA
Total Mercury
Deposition
(ug/m2/year)
14.97
NA
10. 3 ±3.6
12.5
NA = not available
a Methods and assumptions for estimating these values varied with studies.
b Scherbatskoy et al. 1997 d Fitzgerald et al. 1991
c Hoyer et al. 1995 e Engstrom et al. 1994; Swain et al. 1992
was 9.27 jug/m2, with deposition higher in the summer (1 ju,g/m2/month) compared to
winter (0.2yug/m2/month). The pattern for mercury deposition in precipitation is probably
a result of higher mercury concentrations and higher amounts of rain during the
summer; however, insufficient data are available to determine the source of the increased
mercury concentration in the summer.
Atmospheric mercury can also enter the lake from snowmelt, which adds higher
concentrations of mercury to the rivers emptying into Lake Champlain. The total mercury
concentration at three river sampling sites increased two- to six-fold during the peak snowmelt
event as compared to the mean levels over the course of the year (Scherbatskoy et al. 1997).
Because the Lake Champlain basin has such a large ratio of watershed to lake surface
area, it is important to understand the deposition and cycling of atmospheric pollutants by the
largest categories of land use, forests and agriculture, prior to their entry into the lake in runoff.
Unlike the Great Lakes watershed, which has relatively more lake surface area, Lake Champlain's
water surface area makes up only five percent of the basin area. Therefore, it is important to
understand mercury cycling through the terrestrial, atmospheric, and aquatic systems of the
Lake Champlain Basin, as ongoing studies are beginning to address.
SOME PROGRAMS RELATED TO Toxics EMISSIONS AND REDUCTION IN LAKE CHAMPLAIN
Some programs by states have been established to address toxics reduction and to
identify and control source emissions in the surrounding region. These efforts may have
important impact on atmospheric deposition to Lake Champlain basin. Some of these programs
are highlighted below:
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LAKE CHAMPLAIN
The State of New York recently began a program for reducing toxics through a multi-
media approach. The Multimedia Program for Pollution Prevention, when fully
implemented, will integrate environmental protection programs across all "media," such
as air, water, and land, to correct the problem with single media programs.
The State of Vermont conducts a regulatory program for the sources of about 288
hazardous air contaminants (carcinogens, chronic systemic toxicants, and short-term
irritants). Hazardous Ambient Air Standards are established for each of these
contaminants, with requirements imposed on new and existing sources (excludes fossil
fuel combustion) emitting any of these contaminants in excess of a pre-determined
"action level" for each pollutant.
New York and Vermont established a Permit Exchange Agreement in accordance with
the 1988 Memorandum of Understanding, in which both states are informed of permitted
projects in the basin. It allows the affected public to participate in the comment and
review process for the permits. Potential toxics sources subject to this agreement include
air pollution sources within 80 km of each state border that annually emit 50 tons of
volatile organic compounds, sulfur dioxides, nitrogen oxides, carbon monoxide, or
particulate matter, or 5 tons of lead, and/or are subject to Title V of the CAA.
Addressing Toxic Contamination Reduction in Lake Champlain
The Lake Champlain Basin Program
(LCBP) (see sidebar) has been the
institutional framework for coordinating the
development of a comprehensive pollution
prevention, control and restoration plan for
the future of Lake Champlain. The final plan
was released in October 1996 (LCBP 1996),
following public meetings that allowed
interested parties to comment on the an
earlier plan. It is anticipated that the
objectives of the final plan will be
implemented by the Lake Champlain
Steering Committee, which is represented by
environmental officials from New York,
Vermont, and Quebec.
One major issue addressed in the
plan is the prevention of pollution from toxic
substances in order to protect public health
and the Lake Champlain ecosystem.
Implementation of the plan will require
coordination along all levels of government,
organizations, and individuals. The plan identified the following major technical and policy
issues involved in determining the most appropriate and cost-effective actions to reduce toxic
contamination of Lake Champlain.
Lake Champlain Basin Program
The Lake Champlain Special Designation Act,
sponsored by senators from Vermont and New
York, was signed in 1990 and states that Lake
Champlain is a resource of national significance.
The intent of the Act is to create a comprehensive
plan for protecting the future of Lake Champlain
and its watershed. The coordination of the
activities stated in the Act is the responsibility of
the Lake Champlain Basin Program (LCBP), which
is jointly administered by the U.S. EPA, the States
of Vermont and New York, and the New England
Interstate Water Pollution Control Commission.
EPA was given $10 million in funds for five years
to develop a comprehensive pollution prevention,
control, and restoration plan for Lake Champlain;
the final plan was released in 1996. Other
cooperating agencies include the U.S. Fish and
Wildlife Service, U.S. Department of Agriculture,
U.S. Geological Survey, NOAA, and National Park
Service. Formal involvement of Quebec is through
the Lake Champlain Steering Committee.
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Define scope of toxics reduction effort. Research is needed to define the extent of problems
related to toxic pollution in tributaries and in the air. Efforts should be made to improve
source identification, with attention given to reducing both nonpoint and point sources
through all media and remediating current sources of contamination throughout the
Basin.
Focus efforts on Lake Champlain
pollutants of concern and sites of concern.
The List of Toxic Substances of
Concern was established by LCBP,
which identified mercury and PCBs
as Group 1 chemicals and meriting
highest priority for management
action (see sidebar). These two
pollutants are found in the sediment,
water, and biota at levels above
appropriate standards or guidelines
in Lake Champlain. Because of
limited resources to study and
monitor toxic substances, assessments
should focus on specific sites where
contamination is known.
Toxic Substances of Concern in
Lake Champlain by Priority Group
Group 1: PCBs, mercury
Group 2: Arsenic, cadmium, chromium, dioxins/
furans, lead, nickel, PAHs, silver, zinc
Group 3: Ammonia, persistent chlorinated
pesticides, phthalates, chlorinated
phenols, chlorine, copper
Group 4: Other contaminants known to be used
or known to occur in the Basin (e.g.,
volatile organic compounds such as
benzene, pesticides such as atrazine,
strong acids and bases)
Source: LCBP 1996.
Identify sources and quantify loads of
toxic substances. Efforts to determine
sources of toxic substances within Lake Champlain have been initiated, and few "active"
sources have been identified. Two major information gaps in this area that need to be
addressed include the extent of contamination from outside the basin, and the role of
historical sources (e.g., discharged lead batteries released into the waterbody) and
contaminated sediment.
4 Adopt strategy to prevent pollution. Pollution prevention techniques (e.g., source reduction)
may be used to achieve reductions at the source of the problem, and eventually reduce
pollutants in the lake. Vermont and New York have initiated programs to accomplish
this goal, although these programs are not yet integrated into the existing pollution
control programs.
4 Establish firm and defensible toxic reduction goals. The current chemical-by-chemical
approach to managing pollution in Lake Champlain cannot account for the impact of
cumulative or combined effects, and does not protect against unregulated (and
potentially more toxic) chemicals entering the lake; therefore, the reduction strategy
should be expanded to address toxic substances that do not yet exceed human health
standards or cause measurable impacts within the basin.
In addition, as part of these efforts, relevant information gathered from other programs,
such as those initiated in the Great Lakes, should be applied to Lake Champlain. As discussed in
Section IV.A, the Great Lakes Water Quality Agreement Parties adopted a long-term goal for
virtual elimination of sources of specific pollutants. This effort demonstrates the importance of
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LAKE CHAMPLAIN
binational cooperation to address concerns related to reducing toxic emissions in the Great
Lakes, as well as in Lake Champlain.
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IV.C Chesapeake Bay
The Chesapeake Bay, largest of the 130 estuaries in the United States, was the first in the
nation to be targeted for restoration as an integrated watershed, airshed, and ecosystem. The
166,000 km2 drainage basin (or watershed), shown in Figure IV-8, covers parts of six states
(Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of
Columbia, and includes more than 150 rivers and streams. The major tributary basins within the
Chesapeake Bay watershed are shown in Figure IV-9, which is found later in this section.
Economic Highlights of Chesapeake Bay
In 1992, the dockside value of commercial
shellfish and finfish harvests from
Chesapeake Bay was close to $80 million.
In 1993, more than 175,000 pleasure craft
(e.g., sail boats) were registered in the Bay.
Close to 1 million anglers in Maryland and
Virginia made an estimated 600,000 fishing
trips in 1991. Recreational fishing in these
states is estimated at more than $1 billion
annually.
The Chesapeake is a key commercial
waterway, and home to two of the nation's five
major North Atlantic ports (Port of Baltimore,
MD, and Hampton Roads Complex, VA).
More than 90 million tons of cargo were
shipped via the Bay in 1992.
Stretching from Havre de Grace,
Maryland, to Norfolk, Virginia, the
Chesapeake Bay is 314 km long, and ranges
from 5 to 56 km wide. The Bay has over
90,000 km of shoreline (more than the entire
West Coast of the continental United States)
and a surface area of approximately 30,800
km2. Generally shaped like a shallow tray,
the Bay's average depth, including all tidal
tributaries, is only 6 meters, with a few deep
troughs running along much of its length that
average 18 to 21 meters, and reaching 53
meters at the deepest point. To visualize the
relatively large watershed in contrast to the
small Bay volume, imagine that the Bay's
watershed is reduced to the size of this page;
the relative size of the Chesapeake Bay would
be a section 7.2 inches by 0.9 inches in the
lower right hand corner, and the average
depth of the Bay would be represented by
one sixtieth the thickness of the paper (see also Figure IV-8).
Supporting 295 species of finfish, 45 species of shellfish, and 27,000 plant species, the
Chesapeake Bay is a national ecological treasure. The Chesapeake Bay is also home to 29 species
of waterfowl and is a major resting ground along the Atlantic Migratory Bird Flyway. Every
year, one million waterfowl winter in the Bay's basin. Economic highlights of the Chesapeake
Bay are presented in the sidebar above. In all, the Chesapeake is a commercial and recreational
resource for more than 14 million Bay basin residents.
The remainder of Section IV.C presents information on: the Chesapeake Bay Program;
atmospheric deposition of nitrogen to the Chesapeake Bay; and atmospheric deposition of toxic
contaminants to the Chesapeake Bay.
Chesapeake Bay Program
Now in its fourteenth year, the Chesapeake Bay Program is a unique, regional
partnership that has directed and coordinated Chesapeake Bay restoration since the signing of
the historic 1983 Chesapeake Bay Agreement. The principal partners in the Chesapeake Bay
Program include the State of Maryland, the Commonwealths of Virginia and Pennsylvania,
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CHESAPEAKE BAY
FIGURE IV-8
Chesapeake Bay Watershed
V _ Washington
- P X
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CHESAPEAKE BAY
the District of Columbia, the Chesapeake Bay Commission (representing the state legislatures),
and EPA on behalf of the federal government.
The state of the Chesapeake restoration
and protection effort was described in the
latest State of the Chesapeake Bay report
(CBP1995b):
"If the health of the Bay could be likened to that of
a hospital patient, the doctor would report that the
patient's vital signs, such as living resources,
habitat, and water quality, are stabilized and the
patient is out of intensive care. Some vital signs,
such as striped bass and Bay grasses have
improved dramatically, while a few, such as
oysters, are in decline. Other vital signs are mixed
but stable. Nutrients are being reduced, with
phosphorus levels down considerably more than
nitrogen levels and dissolved oxygen remains
steady. Overall, the patient still suffers stress from
an expanding population and changing land use,
but it is on the road to recovery. Taken as a
whole, the concentrated restoration and
management effort begun ten years ago has
produced tangible results—a state of the Bay that
is better today than when we started..."
In 1983, EPA identified an excess of
the nutrients nitrogen and phosphorus, and
the resulting accelerated eutrophication, as
the primary reason for the decline in water
quality in Chesapeake Bay (U.S. EPA 1983).
Excess nutrients stimulate "blooms" of
phytoplankton algae, which then sink to the
bottom of the Chesapeake. In the bottom
waters, decay of the phytoplankton consumes
oxygen, which expands the area of anoxic
bottom waters (i.e., "dead waters" largely
devoid of oxygen and unable to support life).
Blooms of algae also reduce light to
submerged aquatic vegetation (SAV),
resulting in the loss of an important habitat
for juvenile fish and crabs. (A recent
assessment of the state of the Bay is presented
in the sidebar.)
Using the watershed as the central
focus, the Chesapeake Bay Agreement of 1983
recognized the historical decline of the Bay's
living resources and recommended a cooperative approach among the federal and state
governments within the watershed to address problems defined by the 1978-1983 Chesapeake
Bay Research Program. The one-page agreement committed the signatories to work together to
"fully address the extent, complexity, and sources of pollutants entering the Bay." The watershed
approach of the state-federal partnership was chosen as the most practical method for
implementing restoration efforts on both a local and regional scale.
Building on an expanded understanding of the Bay system and increasing experience
with on-the-ground implementation within the cooperative basinwide partnership, a new
Chesapeake Bay Agreement was signed in 1987 that set forth a comprehensive array of goals,
objectives, and commitments to address living resources, water quality, growth, public
information, and governance (Chesapeake Executive Council 1987). The centerpiece of the
agreement was a commitment to achieve a 40 percent reduction of nitrogen and phosphorus
entering the Bay by the year 2000. This measurable goal added a specific direction to ongoing
monitoring, modeling, and nutrient reduction implementation programs. Through the 1987 Bay
Agreement, the signatories also committed to "quantify the impacts and identify the sources of
atmospheric inputs on the Bay system." This seemingly minor commitment at the time set the
stage for a decade-long path to formally address atmospheric deposition as an integral
component of basinwide pollution reduction strategies and implementation actions.
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Atmospheric Deposition of Nitrogen to Chesapeake Bay
This section presents information on the Chesapeake Bay Nutrient Reduction Strategy,
an overview of atmospheric nitrogen loadings to the Bay (from modeling of the airshed, to
nitrogen loadings estimates, to modeling of the watershed and estuary), and areas of uncertainty
and work underway. Although the Chesapeake Bay Agreement and the baywide Nutrient
Reduction Strategy focus on two main nutrients, nitrogen and phosphorus, this section focuses
mainly on nitrogen because atmospheric deposition, the focus of this report, is a significant
pathway of concern for nitrogen loadings only.
NUTRIENT REDUCTION STRATEGY
Sources of Nitrogen Entering the Bay
Sources of the 170.8 million kilograms of
nitrogen delivered annually to the Bay include:
• Point source water discharges (23% or 39.3
million kg), such as sewage treatment plants;
• Atmospheric deposition directly to tidal
waters(9% or 15.4 million kg) and indirectly to
tidal waters (18% or 30.2 million kg); and
• Other nonpoint sources (50% or 85.9 million
kg), such as runoff from agriculture and urban
areas.
The Chesapeake Bay Agreement
commits the signatories to reduce the
"controllable" nutrient loads by 40 percent by
the year 2000. Controllable loads are defined
as the baseline year loads minus the loads
delivered to the Bay under an all- forested
watershed (i.e., a watershed providing only
natural, uncontrollable sources of nitrogen)
within the Bay Agreement signatory juris-
dictions (Linker et al. 1996). In other words,
controllable loads are defined as everything
over and above the total phosphorus or total
nitrogen loads that would have come from an
entirely forested watershed in the States of
Pennsylvania, Maryland, and Virginia, and
the District of Columbia, given existing rates of atmospheric deposition. In this definition, point
source loads are considered entirely controllable. In addition, for the Bay Agreement, emissions
of nitrogen compounds leading to atmospheric deposition are considered uncontrollable.
Nonpoint sources may be controllable or uncontrollable.
To measure the goal of reducing controllable nutrient loads by 40 percent, the Chesa-
peake Bay Program established a 1985 baseline of nutrient loads. The 1985 baseline load was
defined using 1985 point source loads and a 1984-1987 average load for nonpoint sources. The
Chesapeake Bay Program chose the average load of the 1984-1987 period as the base to be repre-
sentative of nonpoint source loads for all tributaries, because river flow and associated nonpoint
source loads may vary depending on rainfall. Table IV-7 presents the 1985 base load and 40
percent reduction target for the major tributary basins of the Bay, and Figure IV-9 presents the
locations of the tributary basins. After the year 2000, the tributary nutrient reduction targets (i.e.,
the 1985 base load minus the 40 percent reduction target) become nutrient caps that are not to be
exceeded at any time in the future even in the face of continued population growth and develop-
ment of the watershed.
In 1992, the basin wide reduction goal was reevaluated and allocated among the ten major
tributary watershed basins. The state jurisdictions, with direct involvement of the public, then
developed comprehensive tributary-specific nutrient reduction strategies within the individual
watersheds. As part of the 1992 amendments to the Chesapeake Bay Agreement, the signatories
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CHESAPEAKE BAY
committed "to incorporate in the Nutrient Reduction Strategies an air deposition component
which builds upon the 1990 Amendments to the federal Clean Air Act and explores additional
implementation opportunities to further reduce airborne sources of nitrogen entering
Chesapeake Bay and its tributaries" (Chesapeake Executive Council 1992).
TABLE IV-7
Chesapeake Bay Basin Nutrient Reduction and Loading Caps by Major Tributary Basin
(in millions of kilograms)
Major Tributary
Watershed Basin
Eastern Shore MD
Eastern Shore VA
James3
Patuxent
Potomacb
Rappahannock
Susquehannac
York
Western Shore MD
Western Shore VA
Nutrient
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Nitrogen
Phosphorus
1985 Base
Load
10.34
0.82
0.82
0.04
19.82
2.80
2.22
0.24
31.16
2.41
3.76
0.39
52.98
2.69
2.90
0.42
12.02
0.77
1.91
0.23
40% Target
Reduction
2.54
0.28
0.18
0.01
6.39
0.97
0.64
0.09
8.48
0.78
1.18
0.15
8.30
1.01
0.86
0.15
4.39
0.30
0.54
0.09
Year 2000 Agreement
Loading Cap
7.80
0.54
0.64
0.03
13.43
1.83
1.59
0.15
22.68
1.64
2.59
0.24
44.68
1.69
2.04
0.27
7.62
0.47
1.36
0.14
a James loads include only loads from Virginia.
b Potomac loads include only loads from Pennsylvania, Maryland, Virginia, and the District of Columbia.
c Susquehanna loads include only loads from Pennsylvania and Maryland.
Source: Adapted from CBP 1992.
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CHESAPEAKE BAY
Susquehanna
Patuxent
Rappahannock
Potomac
W. Shone - MD
E. Shore - MD
E. Shore - MD
York
James
Any reductions in FIGURE IV-9
nitrogen loads brought about MaJ°r Tributary Basins of the Chesapeake Bay
by programs implementing
the CAA are considered to be
additional nutrient load
reductions separate from the
point and nonpoint source
reductions identified in the
tributary nutrient reduction
strategies. CAA implementa-
tion is expected to reduce
nitrogen loads in Chesapeake
Bay beyond the tributary
strategy reductions (CBP
1994a). However, these ad-
ditional reductions may last
only a short time; at some time
after the year 2000, population
growth and increased land
development are expected to
begin eroding the gains made
by the CAA. This expected
increase in nutrient loads may
make it difficult to meet the
caps on nutrient loads to the
Bay. Indeed, it was acknow-
ledged at the time the
tributary strategies were
developed that "achieving a 40
percent nutrient reduction
goal, in at least some cases,
challenges the limits of current
point and nonpoint source control technologies" (Chesapeake Executive Council 1992). To
maintain the restoration progress that will be achieved by the year 2000, the technological limits
of controls on reductions from point and nonpoint sources may have to be expanded to make
further reductions in these areas economically attractive, or other sources of controllable
nutrients may have to be considered to achieve cost-effective ecosystem protection in the Bay.
MODELING Am TO WATERSHED TRANSPORT: THE CHESAPEAKE BAY AIRSHED
A series of linked computer models have been developed by the Chesapeake Bay
Program to simulate the transport of nitrogen from its emission sources to the Chesapeake Bay
watershed and eventually into the tidal Bay waters. As a first step in establishing the air to tidal
waters connection, the "airshed" of the Chesapeake Bay was defined. The boundaries of the
airshed were defined as the contiguous areas whose sources "significantly" contributed (i.e., 75
percent) to atmospheric deposition of nitrogen to the Bay and its surrounding watershed
(Dennis 1997). These boundaries were delineated by running a series of scenarios on the
Regional Acid Deposition Model (RADM), using a predefined point of diminishing return (i.e.,
E. Shore - VA
W. Shore - VA
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CHAPTER IV
CHESAPEAKE BAY
when a 50 percent reduction in emissions from large source regions would be expected to
produce less than a 10 percent reduction in deposition onto the Bay watershed). The resulting
906,000 km2 airshed, shown in Figure IV-10, is about 5.5 times larger than the Bay's watershed
and includes: all of Maryland, Virginia, Pennsylvania, Delaware, the District of Columbia, West
Virginia, and Ohio; most of New York; half of New Jersey, North Carolina, and Kentucky; and
parts of Tennessee, South Carolina, Michigan, Ontario, and Quebec (including Lakes Erie and
Ontario). (See Chapter III for a description of RADM and Dennis (1997) for more information on
the use and limitations of RADM in this study.)
FIGURE IV-10
Chesapeake Bay Airshed
LEGEND
• Watershed
' Airshed
According to the Bay airshed model, about 25 percent of the nitrogen that is deposited on
the Bay and its surrounding watershed originates from sources within the Bay watershed.
Sources located within the jurisdictions of the Bay Agreement signatories of Maryland, Virginia,
Pennsylvania, and the District of Columbia (including those sources that are within the state
boundaries but outside of the Bay watershed) contribute about 40 percent of the nitrogen that
deposits on the Bay and its watershed (Dennis 1997).
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CHESAPEAKE BAY
As defined, the Bay airshed, which accounts for 30 percent of all nitrogen emissions in the
eastern United States and Canada, accounts for 75 percent of the atmospheric nitrogen deposited
onto the Bay and its watershed. The remaining 25 percent of the deposition originates from emis-
sion sources outside the defined airshed (Dennis 1997). Therefore, the Chesapeake Bay airshed as
defined here is smaller than the actual areas of the United States and Canada that contribute to
nitrogen deposition to the Bay watershed. A still unresolved portion of the airshed is the portion
that contributes to atmospheric deposition to offshore ocean waters which, in turn, contributes to
the influx of nitrogen from coastal waters into the southern Chesapeake Bay (CBP 1994b).
FIGURE IV-11
NOX Emission Sources in the Major Bay Influencing States
Other point sources
(e.g., industries)
Other ares sources
(e.g., ships, lawn
equipment)
21%
Utility sources
(;j.g., power plants)
37%
Researchers compared
results from the Bay airshed
model to emissions inventory
data on sources of NOX emissions
and evaluated the contribution of
these sources to nitrogen loads to
the Bay. As shown in Figure IV-
11, data from the emissions
inventory indicate that the
contributions from utility and
mobile sources in the major Bay
influencing states (i.e., Maryland,
New Jersey, New York, Ohio,
Pennsylvania, Virginia, West
Virginia) to NOX emissions are
roughly equal and make up the
majority of emission sources.
Through RADM, these data were
confirmed and the patterns of
nitrate deposition from the two
sources were simulated. The
model simulations suggest that
utilities contribute a majority of
the nitrate that deposits on the
western side of the Bay
watershed and that nitrate deposition from utility emissions shows a decreasing trend from the
western to eastern portion of the watershed (see Figure IV-1211). These simulations further
suggest that mobile sources, associated with NOX emissions from the Boston to Washington,
D.C., metropolitan areas, 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 (see Figure IV-13). In contrast to utility sources, the simulated deposition from mobile
sources shows a decreasing trend from the eastern to western portion of the basin. Model
scenarios simulating the effects of a uniform 50 percent reduction in nitrogen emissions from
utilities alone and then from mobile sources alone show the same west to east, or east to west,
gradients respectively (Dennis 1997).
Mobile sources
(e.g., cars, trucks)
35%
11 In Figures IV-12 and IV-13, a rough outline of the watershed and airshed is also shown. Each shaded area in these
figures represents the percentage of all emissions that emissions from sources within the shaded area contribute to
nitrogen oxides that deposit to the Bay.
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CHESAPEAKE BAY
FIGURE IV-12
RADM Total (Wet and Dry) Nitrate Deposition from Utility Sources
(as a percent contribution of 1990 Base Case)
% Contribution
Watershed
— — — — Airshed
FIGURE IV-13
RADM Total (Wet and Dry) Nitrate Deposition from Mobile Sources
% Contribution
Watershed
— — — — Airshed
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ATMOSPHERIC NITROGEN LOADINGS TO CHESAPEAKE BAY
Atmospheric nitrogen loads from the airshed are transported to the Chesapeake Bay by
three routes: direct deposition, both wet and dry, to the Bay tidal waters (i.e., direct loadings);
indirect deposition, both wet and dry, to the watershed with subsequent runoff and river
transport to the Bay (i.e,. indirect loadings); and deposition, both wet and dry, to adjacent
offshore coastal waters with subsequent transport to the Bay through coastal currents. The first
two processes, direct and indirect deposition to the Bay, are discussed below, as are some
estimates of total loadings to the Bay using both a mass balance approach and computer models.
The third pathway, deposition to offshore coastal waters, is the least understood route and is
discussed later in this section under areas of uncertainty. Different nitrogen compounds that are
measured or estimated in nitrogen loadings are discussed in the box on the next page.
Direct Loadings. The first estimates of atmospheric deposition to the tidal waters of
Chesapeake Bay were made through spatial extrapolation of the National Atmospheric
Deposition Program (NADP) sites in the Chesapeake watershed (Cerco and Cole 1994). The
NADP is a long-term nationwide monitoring program that was started in the 1970s. Based on
the annual loads reported by NADP, and an assumption that dry deposition of nitrate is equal to
the long-term average of wet deposition of nitrate (Fisher and Oppenheimer 1991; Hinga et al.
1991; Tyler 1988), atmospheric deposition of inorganic nitrogen to the tidal waters of the
Chesapeake was estimated as 6.4 million kilograms of nitrate and 1.8 million kilograms of
ammonia. In addition, organic nitrogen was estimated as 6.8 million kilograms (Smullen et al.
1982). Studies have explored the idea that atmospheric deposition may contribute a significant
proportion of phytoplankton nitrogen demands in coastal areas (Paerl 1985; Paerl 1988; Paerl et
al. 1990); phytoplankton require nitrogen, both new and recycled, for growth. Fogel and Paerl
(1991), for example, have estimated that 20 to 50 percent of annual new nitrogen demands for
phytoplankton in Albemarle-Pamlico Sound, NC, may be supplied by direct atmospheric
deposition to the water surface (wet and dry).
Using NADP data, wet deposition directly to the Chesapeake Bay tidal surface waters has
been estimated to range from 3.3 to 4.2 million kilograms of nitrate per year (Fisher and
Oppenheimer 1991; Hinga et al. 1991; Tyler 1988). Though NADP monitoring data allow initial
estimates to be made of atmospheric deposition to the tidal Bay, it is not currently known if the
over-land measurements of wet deposition accurately represent over-water wet deposition. To
investigate this question, a daily precipitation chemistry site was established on Smith Island,
Maryland, in late 1995. This site is providing the first time-series measurements of over-water
wet deposition collected on the east coast.
Although the dry deposition to surface water loading rates of nitrogen compounds have
been estimated for most nitrogen species over open ocean (Galloway 1985; Duce et al. 1991), these
rates may not apply to coastal areas because of the different meteorological processes involved.
Through the use of instrumented Chesapeake Bay Observing System (CBOS) buoys owned by the
University of Maryland, estimates of nitrogen (HNO^ NO % NH,,) dry deposition rates to the Bay
tidal surface waters have been developed (Valigura 1995). These estimates corroborate those given
by other investigators to some extent, but still cover a wide range of values, from 0.7 to 2.2 million
kilograms of nitrate per year. From this data set, calculations were performed to determine the
effect of atmospheric dry deposition on phytoplankton dynamics. This analysis demonstrated that
dry deposited nitrogen may provide 10 percent of the annual "new nitrogen" demands by
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CHESAPEAKE BAY
phytoplankton in Chesapeake Bay, and that individual events could supply up to 75 percent of the
new demands for periods of several days (Malone 1992; Owens et al. 1992).
Characterization of Nitrogen Compounds
Most atmospheric nitrogen compounds (excluding N2and Np, which are relatively unreactive in the
lower atmosphere) fall into two categories: reactive nitrogen and reduced nitrogen. In addition, some
organic nitrogen species arise in the atmosphere from the interaction between nitrogen oxides and certain
hydrocarbons. The relative portions of the different nitrogen forms in nitrogen loadings can vary widely
based on source types and locations, proximity of sources to receiving waters, atmospheric transport, and
physical and chemical transformations. Current estimates are that reactive nitrogen is the largest contributor
to atmospheric deposition in coastal waters (40 to 60 percent), with ammonia (20 to 40 percent) and organic
nitrogen (0 to 20 percent) also contributing significant amounts.
Reactive nitrogen compounds, primarily oxides of nitrogen, are emitted to the atmosphere through
both natural and anthropogenic pathways, overwhelmingly (95 percent) as nitric oxide (NO). Natural NO
sources include emissions from soils and generation by lightning; dominant anthropogenic sources include
emissions from automobiles, power plants, and biomass burning. The dominant source of reactive nitrogen
oxides present in air over North America is high-temperature combustion (e.g., power plants, automobiles).
NO generated by combustion reacts quickly in the lower atmosphere, forming nitrogen dioxide (NO j. The
NO2 is rapidly converted back to NO by ultraviolet light (photochemistry), then NO reacts again, resulting in a
cycle driven by volatile organic compounds. From this photochemical cycle, ozone (O ^ is produced. The
cycle is broken when NO2 terminates into stable products, principally nitric acid vapor (HNO3), and the NO
gets used up. The ozone issue is therefore intimately related to the NOx(defined as NO + NO2) question.
NO2 slowly deposits to the underlying surface (too slowly to break the cycle), but nitric acid vapor (HNQ) is
easily and quickly deposited. HNO3 is the source of most of the reactive nitrogen deposited to the earth's
surface.
Reduced nitrogen compounds include ammonia (NHj) and ammonium (NH4"). NH3is emitted into the
atmosphere through both natural and anthropogenic pathways. Natural sources of NH 3include microbial
decomposition of organic nitrogen compounds in soils and ocean waters and volatilization from animal and
human wastes. Anthropogenic sources include the manufacture and release of commercial and organic
fertilizers during and after application and fossil fuel combustion. Human activities such as manure
management and biomass burning exacerbate emissions from otherwise natural processes. NH 3is a highly
reactive compound and has a short residence time in the atmosphere. It is primarily emitted at ground level
and quickly deposits to the area near its source unless it reacts with other gaseous chemicals (e.g., SO 2
HNO3) and is converted to NH4+aerosol (Asman 1994; Langland 1992). NH4+ can be transferred regionally
as ammonium salts, such as ammonium nitrate NH4NO3and ammonium sulfate (NH4)2SO4, and these salts
are the primary contributor to NH4+concentrations measured in precipitation. Scavenging of NH3 by
precipitation can also be a major source of NH4+in precipitation.
Organic nitrogen may be a significant fraction of the total nitrogen measured in precipitation (Cornell et
al. 1995; Gorzelska et al. 1997; Milne and Zika 1993). Data on the deposition of organic nitrogen has been
limited, however, because of the paucity of reliable measurements, the historical variability in analytical
techniques and results, and the current lack of suitable and uniform analytical measurement techniques. In
fact, only wet deposition of dissolved organic nitrogen (DON) has been addressed. Various estimates for the
relative flux of organic versus total nitrogen via wet deposition range from less than 10 percent to greater
than 60 percent. The contribution of the unresolved organic fraction may significantly augment the
atmospheric deposition of nitrogen to coastal waters. However, in addition to the lack of dry deposition data,
there remain many conceptual questions related to source identification and the bioavailability of
atmospheric organic nitrogen.
Sources: Luke and Valigura 1997; Paerl et al. 1997; Valigura et al. 1996.
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Indirect Loadings. Quantifying indirect loadings of nitrogen to Chesapeake Bay, which
refers to the atmospheric deposition of nitrogen to the terrestrial watershed and subsequent
transport of the nitrogen from the terrestrial watershed to Bay surface waters, is an important
component of the estimate of total atmospheric deposition of nitrogen to the Bay, yet it is largely
uncertain. NADP monitoring data provide an initial estimate of the atmospheric deposition to
the Chesapeake Bay watershed. Generally, higher deposition levels are found in the northern
portions of the basin. In fact, some of the highest readings for atmospheric deposition of nitrate
in the NADP monitoring network come from the northern sections of the Chesapeake basin.
Greatest uncertainty is in dry deposition of nitrogen, which is not routinely measured by NADP.
The amount of atmospheric nitrogen transferred to surface waters within a given
watershed depends on land use, total nitrogen loading from atmospheric, fertilizer, animal
waste, and biosolid sources, the amount of soil nitrogen, characteristics of the soil, site rainfall
and temperature, the elevation and slope of the land, and the type, age, and health of the
vegetative cover. These characteristics vary independently, making it difficult to determine the
fate of atmospherically deposited nitrogen over any area of significant size. However, several
classification schemes for forested sites have been developed to evaluate a site's potential to
retain and leach nitrogen (Melillo et al. 1989; Johnson and Lindberg 1992; Stoddard 1994).
One classification scheme in particular has helped organize thinking about nitrogen
retention by classifying forest systems based on stages of nitrogen saturation (i.e., the extent to
which the system is saturated with nitrogen; the more saturated a system, the more likely to
leach nitrogen) (Stoddard 1994). The classifications range from Stage 0, where forest nitrogen
transformations are dominated by plant and microbial assimilation (uptake) with little or no NO3
export from the watershed during the growing season, to Stage 3, where nitrogen deposition is
well in excess of assimilation and has reduced plant and microbial assimilation capacities
resulting in greater export of atmospheric nitrogen as well as losses from mineralization of soil
organic nitrogen. Study sites in the southern portions of the Chesapeake Bay watershed
generally fall into the low nitrate export classification (Stages 0-1), while the northern portions
have generally high to medium export classifications (Stages 1-2).
Total Loadings Estimates Using A Mass Balance Approach. The role of atmospheric
transport as an important path for nitrogen deposition to estuarine areas was first publicized in
1988 (Fisher et al. 1988). Based on a mass balance analysis using 1984 hydrology data, the authors
estimated that one-third of the nitrogen entering the Chesapeake Bay is deposited from the
atmosphere. Several subsequent efforts (Fisher and Oppenheimer 1991; Hinga et al. 1991; Tyler
1988) to quantify atmospheric nitrogen loadings to Chesapeake Bay produced "best-estimate
loadings" ranging from 25 percent (Fisher and Oppenheimer 1991) to about 33 percent (Hinga et
al. 1991) of the total nitrogen loads to the Chesapeake. (A discussion of the uncertainties in a
mass balance approach from one of these studies is presented in the sidebar on the next page.)
The approach taken in these mass balance studies can be divided into two components:
(1) estimating wet and dry deposition; and (2) estimating nitrogen retention. A central difficulty
in mass balance studies is the use of average land use values of nitrogen retention. Nitrogen
retention assumptions used in three of the Chesapeake Bay studies are presented in Table IV-8.
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TABLE IV-8
Nitrogen Retention Assumptions Used in Chesapeake Bay Loading Studies
(as a percentage of nitrogen loading)
Land Use
Forest
Pasture
Cropland
Residential
Tyler 1988
95.2-100.0
93.7-99.96
76.0-99.97
62.0-95.3
Fisher and
Oppenheimer 1 991 a
80.0(51.0-100.0)
70.0(51.0-90.0)
70.0
35.0 (0.0-70.0)
Hingaetal. 1991a
80.0 (25.0-95.0)
80.0 (25.0-95.0)
60.0 (45.0-75.0)
25.0(10.0-50.0)
' Numbers in parentheses indicate range tested.
Assembling an adequate understanding of long-term behavior when the processes
involved are fundamentally episodic is another major challenge of contemporary models. Some
studies indicate that the majority of the atmospheric wet deposition occurs during a few
episodes (Dana and Slinn 1988; Fowler and Cape 1984), such that the wet-deposited nitrogen (as
well as previously dry-deposited nitrogen) is deposited directly to, or flows quickly into, the
surface waters without intermediate reduction in concentration. Despite these difficulties, mass
balance studies provide a good first-order estimate of nitrogen loading to Chesapeake Bay.
Experimental manipulation at the
watershed scale is being conducted at a
few U.S. locations (Kahl et al. 1993;
Norton et al. 1994). Work from these sites
is providing information on the cycling of
nitrogen in forested catchments and is
fully supportive of the conclusion that
atmospheric deposition contributes to
nitrogen loading of coastal waters
through the export of atmospherically
derived nitrogen. Results of these long-
term experiments are just beginning to be
published. An example is the Bear Brook
watershed in Maine. Divided into
treatment and control catchments, the
treated catchment received increased
nitrogen loading in the form of labeled
ammonia. The treated watershed ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
response was an immediate increase in
stream nitrate export (Norton et al. 1994; Uddameri et al. 1995).
Total Loadings Estimates Using the Chesapeake Watershed and Estuary Models. The
Chesapeake Watershed Model (discussed in more detail below) is one approach to
disaggregating the separate components of terrestrial and river nitrogen dynamics in the basin,
along with the temporal effects of high loading during rainfall events. The estimate of
Inherent Uncertainties in
Mass Balance Approach
"It would not be difficult to make the [mass balance]
calculations appear more elegant by subdividing the
watersheds into more land use types, using a detailed
data base of land uses, assembling more detailed lists
of point source and agricultural inputs, and using some
technique for contouring deposition over the
watershed. None of these approaches are likely to
make better calculations. More precise and reliable
estimates of the magnitudes of inputs of
atmospherically-deposited nitrogen to coastal waters
will require significant advances in the understanding
of many processes responsible for the behavior of
nitrogen in terrestrial ecosystems and in rivers and
streams."
Source: Hinga et al. 1991.
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atmospheric nitrogen loads for both direct and indirect deposition is 27 percent of the annual
nitrogen load delivered to the Chesapeake Bay. This estimate was developed using the 1992
Watershed Model (Linker et al. 1993) and is consistent with the range reported by Chesapeake
Bay mass balance studies (i.e., 25 to 33 percent). Further refinements are being made to the
Watershed Model and an update of the estimate of atmospheric deposition is expected by
September 1997.
To estimate wet deposition, the Chesapeake Bay Program combined output from a
regression model developed from NADP weekly and daily precipitation chemistry
measurements with data from the NOAA rainfall network. This approach yields daily estimates
of rainfall to 74 sub-basins of the Chesapeake Bay watershed. Dry deposition was assumed to be
equal to wet deposition for over-land areas and 44 percent of wet deposition for over-water
areas. Indirect atmospheric loadings from the over-land portion of the watershed were
estimated using the Chesapeake Bay Program Watershed Model.
The estimate of a 27 percent contribution of atmospheric deposition to total nitrogen
loadings to the Chesapeake Bay falls within the range reported for other major eastern and Gulf
coast estuaries, which are discussed in Section IV.D and summarized in Table TV-11 in that
section.
MODELING THE CHESAPEAKE BAY'S WATERSHED AND ESTUARY
Water quality models of the Chesapeake Bay's watershed and estuary have been in use
since the mid-1980s (CBP 1987; Donigian et al. 1991; Hartigan 1983; Thomann et al. 1994). The
1987 Bay Agreement's 40 percent nutrient reduction goal was based, in large part, on findings
from these models.
The first model of the Bay watershed was completed in 1982 and provided a basin-by-
basin assessment of the relative importance of point source and nonpoint source controls of
nutrients (NVPDC 1983). Subsequent refinements of the Watershed Model established the
importance of animal waste management in the watershed (Donigian et al. 1991), the delivery to
the Bay of atmospheric deposition loads from the watershed (Donigian et al. 1994), and the
development of tributary allocation loads of nitrogen and phosphorus to achieve the 40 percent
nutrient reduction goal (Thomann et al. 1994).
In a parallel effort, the first model of the Chesapeake estuary was completed in 1987 to
evaluate the impact of nutrient reduction scenarios on the Bay's dissolved oxygen concentrations
(CBP 1987). Results from the steady-state Estuary Model indicated that a 40 percent reduction in
nutrient loads would significantly reduce anoxia (dissolved oxygen concentrations less than 1
mg/L) in the Bay mainstem during average summer (June-September) conditions (CBP 1988).
The 40 percent controllable nutrient reduction goal, under the 1987 Bay Agreement, was based in
large part on these findings.
A reevaluation of the Bay's nutrient reduction goal and a review of the progress made in
reducing nutrients was scheduled for 1992. In advance of this reevaluation, researchers began
refining and integrating the Watershed and Estuary Models (Figure IV-14). For example, the
Watershed Model was updated with greater detail of agricultural and atmospheric sources and
was linked to the Estuary Model (Donigian et al. 1994). Providing a predictive framework for
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National Atmospheric Deposition Program [Date
determining nutrient loads deliver- FIGURE IV-14
ed to the tidal Bay under different Watershed and Estuary Model Integration
source reduction scenarios, the
Watershed Model simulated
delivered nutrient loads with
changes in land use practices and
levels of wastewater treatment
(Thomann et al. 1994). The Estuary
Model was upgraded to add a sed-
iment processes model and a hy-
drodynamic model, and was linked
with the Watershed Model to
accept Watershed Model nutrient
loads as data input (Cerco and Cole
1994; DiToro and Fitzpatrick 1993;
Johnson et al. 1991).
The integrated Watershed
and Estuary Model of the Chesapeake Bay was used to estimate water quality improvements that
would be realized upon reaching the Bay Agreement goal of reducing controllable nutrients by
40 percent. Through the application of these models, the Bay Program partners established the
Bay Agreement tributary nutrient allocations of nitrogen and phosphorus to be achieved by the
year 2000 and maintained thereafter.
Hydrodynamic Model
FIGURE IV-15
Integrated Model Improvements
Regional Atm spheric Deposition Model (F A )M)
Estu
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CHAPTER IV
CHESAPEAKE BAY
integrated model (Figure IV-15) will simulate and evaluate the overall loads of controllable and
uncontrollable nitrogen from the surrounding airshed and watershed, and the impact of these
loads on the ecosystem. This model will be one of the tools used by Chesapeake Bay Program
state and federal managers to formulate additional nitrogen reduction steps needed to achieve
the 40 percent reduction goal and maintain the cap on nutrient loadings after the year 2000.
WATER QUALITY BENEFITS FROM REDUCING NITROGEN EMISSIONS
Using the Watershed Model, several scenarios were developed to examine the effective-
ness of air emission controls compared to traditional point source and nonpoint source controls
on the delivery of nutrient loads to the Chesapeake Bay. The Watershed Model scenarios were:
4 Base Case Scenario: This scenario represents the base year 1985 loads to the Chesapeake
Bay.
4 Bay Agreement Scenario: This scenario represents the 40 percent controllable nutrient load
reduction to be achieved by the year 2000 (as discussed under Nutrient Reduction
Strategy in this section).
4 Bay Agreement plus CAA Scenario: The scenario represents the controls on point and
nonpoint source loads through the Bay Agreement, plus the atmospheric load reductions
expected under full implementation of the CAA titles I (reductions in ground level
ozone), II (mobile sources), and IV (utility sources).
4 Bay Agreement plus Ozone Transport Commission (OTC) Scenario: The scenario evaluates
reductions from the controls on point and nonpoint source loads through the Bay
Agreement, plus the effects of implementation of CAA titles I, II and IV, as well as
additional nitrogen reductions to reduce ground level ozone in the mid-Atlantic and New
England metropolitan regions as called for by the Ozone Transport Commission.
4 Limit of Technology Scenario: This scenario estimates the nutrient reductions that may be
realized using the current practical limit of point and nonpoint source control
technologies, including conservation tillage for all cropland implemented; the
Conservation Reserve program fully implemented; nutrient management, animal waste
controls, and pasture stabilization systems implemented where needed; a 20 percent
reduction in urban loads; and point source effluent controlled to a level of 0.075 mg/L
total phosphorus and 3.0 mg/L total nitrogen. This scenario is significant because it
determines the limit of currently feasible control measures.
4 No Action Scenario: This scenario represents loads that would occur in the year 2000 given
population growth and projected changes in land use. The controls in place in 1985 were
applied to the year 2000 point source flows and land use, representing the loading
conditions without the nutrient reductions stipulated in the Bay Agreement.
These reduction scenarios are part of an effort to evaluate options for achieving the 40
percent nutrient reduction goal. Land-based nonpoint source and wastewater treatment facility-
based point source reduction actions, planned for implementation in many Chesapeake tributary
watersheds, are approaching the limits of technology. Options for reductions in air emissions are
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being explored for maintaining the targeted 60 percent nutrient loadings cap beyond the year
2000 in the face of a growing population and resultant development in the watershed. Different
options will have different costs and effectiveness with regard to water quality improvements,
and a range of options should be evaluated to find the best approach.
The water quality improvement from the expected reduction in nitrogen emissions under
each scenario are shown in Figure IV-16. The improvement in water quality reflects the
estimated reductions in Bay bottom waters having no dissolved oxygen (i.e., reduction in
Chesapeake anoxia or "dead waters"). Decreased nitrogen loadings will result in decreased water
column nitrogen which will, in turn, decrease the growth of algae and improve the level of light
penetration necessary to support the critically important SAV (Batiuk et al. 1992; Dennison et al.
1993; Thomann et al. 1994).
FIGURE IV-16
Reductions in Anoxia Under Nutrient Reduction Scenarios
o
I
a:
30
20
10
-10
32
24
26
20
\1985Baise
-14
Bay
Agreement
Bay Plus
CAA
Baiy Plus
OTC
Limit of
Technology
No Action
Scenarios
The CAA and OTC scenarios indicate that these controls provide for nitrogen loading
reductions and water quality improvements above and beyond those provided by implemen-
tation of the Chesapeake Bay Agreement commitment of 40 percent reduction in controllable
nitrogen. Relative reductions from controls on sources of atmospheric deposition vary by
tributary basin, with the more sensitive tributaries being the Susquehanna and the Potomac.
These basins receive the highest deposition loads in the Chesapeake watershed and are among
the most responsive to reductions in atmospheric deposition.
Though the differences between scenarios in percent reductions in anoxia might seem
small, air emission controls could account for a fifth and a third of the baywide nitrogen load
reduction goal through CAA implementation and OTC reductions, respectively. Such reductions
could make achieving the 40 percent reduction target more feasible, and make maintaining a cap
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on any further increases in nutrient loadings beyond 2000 possible. These additional reductions
are especially important in the face of increasing population and watershed development that
studies predict will increase the significance of atmospheric deposition as a source of nitrogen
loadings to the Chesapeake Bay in the coming decades (Fisher et al. 1988; Pechan 1991).
AREAS OF UNCERTAINTY AND WORK UNDERWAY
Nitrogen retention, the relative loadings of ammonia and organic nitrogen, and dry
deposition to water surfaces are a few of the remaining areas of significant uncertainty in
estimating atmospheric nitrogen loads. Several specific examples of areas of uncertainty are
discussed below.
4 Nitrogen retention within watersheds makes a big difference in the proportion of the
atmospheric contribution to nitrogen loading to the Bay. Different retention assumptions
in mass balance analyses lead to an uncertainty in the estimate of this contribution by
more than a factor of two.
4 Ammonia and organic nitrogen contribute a large portion of nitrogen deposition, perhaps
more than 25 percent of the total atmospheric nitrogen load. However, it is unknown to
what degree their sources are controllable, and they may be changing with time. For
example, airborne ammonia emissions from agricultural animal operations could
increase.
4 Estimates of the relative contribution of dry deposition to the total atmospheric deposition
loadings range from 25 to 63 percent (Duce et al. 1991; Levy and Moxim 1987; Logan
1983; Lovett and Lindberg 1986; Sirois and Barrie 1988; Walchek and Chang 1987). Faced
with this wide range of estimates, many investigators choose to set the dry deposition
loading equal to the measured wet deposition loading. This assumption is known to be
questionable. While site-specific data to refine the estimate are lacking, recent
evaluations indicate that dry deposition to tidal water surfaces is about 25 percent of wet
deposition to tidal water surfaces (Luke and Valigura 1997).
4 1990 baseline emission estimates continue to be refined. Estimates of emissions from off-
road vehicles have been significantly improved. Ship emissions in harbors are suspected
to be significantly underestimated (Booz-Allen & Hamilton 1991). While emissions from
these sources are not large in the aggregate, they occur close to the Bay tidal surface
waters, and thus have an influence greater than their national fractions would imply.
Nitrogen emissions from on-road vehicles continue to be a source of uncertainty.
4 Particulate nitrate (which has a low deposition velocity) and nitric acid (which has a high
deposition velocity) are currently indistinguishable by RADM, leading to modeling
uncertainty.
4 The contribution of atmospheric nitrogen deposition to offshore ocean waters has not yet
been characterized. The ocean waters exchange with waters of the Chesapeake Bay and
thus may be a source, or a sink, of nitrogen loads to the Bay.
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To reduce existing uncertainties in atmospheric loadings estimates, the Chesapeake Bay
Program convened a workshop in June 1994, inviting scientists and managers with expertise and
experience in understanding or managing atmospheric deposition. The challenge given to
attendees was to construct a list of practical studies that would make the greatest impact on
reducing the current uncertainty in estimates of the contribution of atmospheric deposition to
declining aquatic ecosystem health. The resulting list (CBP 1995a) is summarized below:
4 Priority 1: Conduct intensive, coordinated, and integrated monitoring studies at special
locations within the watershed that characterize wet deposition, dry deposition, and local
catchment area.
4 Priority 2: Improve existing atmospheric models (e.g., reduce grid size, account for the
effect of mountains).
4 Priority 3: Improve models of chemical retention in watersheds.
4 Priority 4: Improve emissions inventories and projections.
4 Priority 5: Conduct measurements to extend vertical and spatial meteorological and
chemical concentration coverage in models.
4 Priority 6: Establish an extensive array of less intensive measurement stations to improve
spatial resolution for selected variables.
To improve the cross-media modeling capabilities and to reduce existing sources of
uncertainty in atmospheric deposition loadings estimates, the following work is underway
through cooperation between EPA, state and federal agencies, and universities:
• Measuring the concentration of atmospheric organic nitrogen within the
Chesapeake Bay watershed;
• Measuring dry deposition of nitrate to tidal surface waters of the Bay;
• Investigating the atmospheric deposition of dissolved organic nitrogen and its
isotopic composition (delta (5) 15N);
• Linking daily atmospheric deposition and resultant nitrogen runoff from pasture,
forested, and urban lands within the Chesapeake Bay Watershed Model;
• Decreasing the grid size of RADM across the Bay watershed to increase the spatial
resolution and improve the resultant model scenario output; and
• Linking RADM with the Watershed, Estuary, and Water Quality models,
including simulation of atmospheric deposition to offshore ocean waters and
exchange of the ocean waters with Chesapeake Bay waters.
The result of this and other work will become part of the integrated model of the Bay's airshed,
watershed, estuary, and ecosystem (discussed above), which is expected to be completed in early
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1997. A series of management scenarios, similar to the modeling scenarios discussed above, are
also expected to be completed in 1997 to examine the most feasible and cost-effective
combination of point source, nonpoint source, and air deposition reductions to meet the
Chesapeake Bay Agreement commitment to cap nutrient loadings in 2000 at 60 percent of 1985
controllable base loadings and to ultimately restore the water quality conditions necessary to
fully support the Bay's invaluable living resources.
Toxic Contaminant Deposition to the Chesapeake Bay
CHESAPEAKE BAY BASINWIDE Toxics STRATEGY
The 1987 Chesapeake Bay Agreement committed the signatories to "develop, adopt, and
begin implementation of a basinwide strategy to achieve a reduction of toxics consistent with the
Clean Water Act of 1987, which will ensure protection of human health and living resources"
(Chesapeake Executive Council 1987). The resultant strategy, adopted in 1989, initiated a multi-
jurisdictional effort to more accurately define the nature, extent, and magnitude of Chesapeake
Bay chemical contaminant problems and to initiate specific chemical contaminant reduction and
prevention actions (Chesapeake Executive Council 1989). Building on a two-year reevaluation of
the strategy and increased understanding of the nature of the Bay's toxics problems, a revised,
farther-reaching strategy was adopted in 1994. The 1994 Chesapeake Bay Basinwide Toxics
Reduction and Prevention Strategy recognized the contribution of atmospheric deposition as a
significant source of chemical contaminant loadings to the Bay. Within the basinwide strategy,
the signatories committed to establishing a more comprehensive loadings baseline and setting an
atmospheric deposition loading reduction target to be achieved over the next decade (Chesapeake
Executive Council 1994).
In 1991, the Chesapeake Bay Program adopted its first Chesapeake Bay Toxics of Concern
list, principally to identify and provide concise documentation on chemical contaminants that
adversely affect the Bay or have a reasonable potential to do so. This list provided Chesapeake
Bay region resource managers and regulators with a baywide consensus of priority chemicals
and the information necessary to target these chemical contaminants for strengthened regulatory
and prevention actions or additional research, monitoring, and assessment. Based on ambient
concentrations of chemical contaminants and aquatic toxicity data, the toxic pollutants that
represented immediate or potential threats to the Chesapeake Bay system were identified. The
Toxics of Concern list (see sidebar) includes
several pollutants of concern for atmospheric
deposition to the Great Waters (cadmium,
chlordane, lead, mercury, PAHs, and PCBs).
In addition, a Chemicals of Potential Concern
list was identified for the Chesapeake Bay
(see sidebar) and includes two pollutants of
concern for the Great Waters (dieldrin and
toxaphene). Clear evidence is lacking that the
contaminants on the Chesapeake Bay list of
Chemicals of Potential Concern actually cause
, , , . .. , . , permethrin, toxaphene, and zinc.
or have reasonable potential to cause adverse
effects in the environment, but the
Chesapeake Bay Program believes these
Chesapeake Bay Toxics of Concern
Toxics of Concern: atrazine, benz(a)anthracene,a
benzo(a)pyrene,a cadmium, chlordane, chromium,
chrysene,3 copper, fluoranthene,3 lead, mercury,
napthalene,3 polychlorinated biphenyls (PCBs),
and tributyltin.
Chemicals of Potential Concern: alachlor, aldrin,
arsenic, dieldrin, fenvalerate, metolachlor,
! A polycyclic aromatic hydrocarbon (PAH).
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chemicals warrant enough concern to be carefully monitored and tracked. For example, a
number of the chemicals listed as being a potential concern are either banned or restricted
pesticides that have residues still remaining in the ecosystem at elevated levels but below
thresholds of concern; others are chemicals of increasing concern due to use patterns or potential
for toxicity to Bay resources.
In response to a commitment within the 1994 Basinwide Toxics Strategy, the Toxics of
Concern list is currently being evaluated and revised using a risk-based chemical ranking system
incorporating source, fate, and exposure/effects ranking factors. In-depth analyses of the top-
ranked chemicals will lead to the selection of a revised Toxics of Concern list in 1997.
CHESAPEAKE BAY Toxic CONTAMINANT ATMOSPHERIC DEPOSITION STUDIES
Studies conducted in the southern
Chesapeake Bay in the early 1980s suggest
that the atmosphere is a significant source of
organic contaminants to the Bay, such as
organic carbon (Velinsky et al. 1986) and
anthropogenic hydrocarbons, including PAHs
(Webber 1993). While these earlier studies
demonstrated the potential importance of the
atmosphere in supplying contaminants to the
Chesapeake Bay, they were limited by their
methodologies (i.e., bulk deposition
sampling, which is imprecise) and their
relatively limited temporal and spatial scope.
An assessment of the extent of toxic
contamination in the Bay is presented in the
sidebar.
To further explore the issue of
atmospheric loadings of toxic contaminants to
the Bay, 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. The primary
objective of the CBADS network was to
provide the best estimate of total annual
atmospheric loadings of a variety of trace
elements and organic contaminants directly
to the surface waters of the Chesapeake Bay.
Because accurate estimates of baywide annual
loadings require characterizing the spatial
and temporal variability in contaminant loads in the atmosphere and in depositional fluxes to the
Bay, CBADS collected data to help characterize this variability.
Extent of Toxic Contamination
in Chesapeake Bay
Prior to adoption of the 1994 Chesapeake
Bay Basinwide Toxics Reduction and Prevention
Strategy, the Chesapeake Bay Program
conducted a two-year, in-depth evaluation of the
nature, extent, and magnitude of toxic
contaminant-related problems within the
Chesapeake Bay. Through the evaluation, no
evidence was found of severe baywide impacts
from chemical contamination, unlike other
problems facing the Chesapeake Bay, such as the
impacts from excess nutrients. The Program did
document severe, localized toxicity problems,
adverse effects from chemical contamination on
aquatic organisms in areas previously considered
unaffected, and widespread low levels of chemical
contamination in all Bay habitats sampled.
Existing state and federal regulatory and
management programs continue to reduce the
input of potentially toxic chemicals to the
Chesapeake Bay. Measured concentrations of
many of these chemical contaminants in the Bay's
bottom sediments, shellfish, fish, and wildlife have
also generally declined, although elevated levels
occur in several industrialized areas and some
increasing trends have been observed. Progress
in reducing the point sources of these chemical
contaminants is offset by significant nonpoint
source inputs of chemical contaminants (e.g.,
urban stormwater runoff, atmospheric deposition)
from increasing development and urbanization of
the Bay watershed.
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Based on previous studies of wet deposition in the region (e.g., Tyler 1988) and given the
resources available for the network, three non-urban shoreline locations — Wye Institute and
Elms Institute, Maryland, and Haven Beach, Virginia — were selected and sampled from 1990 to
1993. These three sampling site locations, as well as other monitoring sites around Chesapeake
Bay, are shown in Figure IV-17. In establishing this initial network, the influence of urban areas
was purposely avoided by locating the sites more than 50 kilometers from metropolitan areas
(similar to the initial non-urban stations for the Great Lakes deposition network, the Integrated
Atmospheric Deposition Network (IADN)). By minimizing possible urban influences, the
resulting CBADS loading estimates are considered to be minimum values.
CBADS evaluated atmospheric loadings directly to the Bay only. Although it is most
likely that some fraction of the toxic contaminants deposited from the atmosphere to the
watershed of the Chesapeake Bay are ultimately transported to the surface waters, this study did
not attempt to characterize indirect loadings for two main reasons:
• Because deposition to the various land surfaces is likely much different than that
to the water surface, fluxes measured at the shore-based stations cannot be
extrapolated with confidence to the watershed; and
• The large uncertainty in the understanding of the fate of materials deposited to
the land surface (i.e., the fraction transmitted to the receiving water) precludes the
simple estimation of the indirect atmospheric loading of contaminants to the
Chesapeake Bay in more than a rough estimate.
The CBADS data on concentrations in air, concentrations in precipitation, and wet and
dry aerosol depositional fluxes are presented in Baker et al. (1997) and are summarized below.
These data were collected for two groups of contaminants: trace metals (aluminum, arsenic,
cadmium, chromium, copper, iron, manganese, nickel, lead, selenium, and zinc); and organic
contaminants (14 different PAHs and total PCBs). Cadmium, lead, PAHs, and PCBs are
pollutants of concern for atmospheric deposition to the Great Waters. Mercury data are being
collected but have not yet been compiled, and data on other Great Waters pollutants of concern
were not collected. For detailed results, a discussion of sampling methods, or a description of the
limitations of the study, refer to Baker et al. (1997).
Concentrations in Air. Air concentrations for trace metals were determined by
measuring the elemental composition of aerosol particles less than 10 //m in diameter. The
elemental composition was dominated by the crustal elements aluminum and iron, as well as
sulfur (in the form of sulfate). During 1991 and 1992, concentrations averaged over the three
sampling sites were 116, 111, and 2,123 ng/m3 for aluminum, iron, and sulfur, respectively. Trace
element concentrations averaged over the same period ranged from 0.16 ng/m3for cadmium to
12.6 ng/m3 for zinc, with lead averaging 3.88 ng/m3. The fraction of each element derived from
non-crustal (e.g., combustion) sources was estimated based on the average concentration of
elements in the Earth's crust (Turekian and Wedepohl 1961), and assuming all of the measured
aluminum associated with aerosol particles is derived from erosion of soils. In the Chesapeake
Bay region, non-crustal sources supply greater than 95 percent of most of the elements measured
on aerosol particles (Wu et al. 1994). Arsenic, cadmium, lead, sulfur, and selenium are almost
exclusively non-crustal, and are likely introduced into the atmosphere as a result of combustion
of fossil fuels and incineration of municipal wastes.
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CHESAPEAKE BAY
FIGURE IV-17
Sampling Locations for
Chesapeake Bay Toxic Contaminant Atmospheric Deposition Studies
Source: Baker etal. 1996
A Chesapeake Bay Atmospheric
Deposition Study (1990 - 1993)
n NADP
Atmospheric Exchange Over
Lakes & Seas (AEOLOS, 1995 - )
Other Sites
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The measured concentrations of trace elements were generally within a factor of two
among the three sampling sites. On an average annual basis, concentrations slightly decrease
from north (Wye) to south (Haven Beach), except sulfur, which is 15 percent higher at Elms (1991
and 1992) and Haven Beach (1992) than at the Wye site. The general decreasing trends observed
from north to south, along with increasing sulfate, may indicate higher levels of low sulfur
combustion sources (e.g., incinerators, vehicles) in the northern reaches of the Chesapeake Bay.
In general, the spatial variability in the atmospheric concentrations of trace elements between
sites (from north to south) is substantially lower than corresponding temporal trends.
Semivolatile organic chemicals exist in the atmosphere as gases and also are associated
with aerosol particles (Pankow 1987). In this study, bay wide annual average concentrations of
PAHs in air ranged from 16 ng/m3 for dibenz[a,/z]anthracene to 2,590 ng/m3 for phenanthrene.
Atmospheric concentrations were quite variable with individual measurements ranging from
one-tenth to ten times the annual average concentrations. These variations likely result from
sampling air masses coming from differing directions, from changes in local and regional
emissions, and from differences in atmospheric degradation and deposition rates. These
variations show a seasonal pattern. For example, increased concentrations of gas-phase PAHs,
such as pyrene, during the summer months may reflect both higher temperatures (i.e., enhanced
volatilization) and increased coal and oil combustion to meet the electricity demand of air
conditioning. Increases in the atmosphere of particulate PAHs, such as benzo[«]pyrene, may
result from local burning of yard wastes and of wood for home heating. Some variation in
atmospheric levels of organic chemicals may result from the efficient removal of particulate
PAHs by precipitation (Poster and Baker 1996a, 1996b). In general, the magnitude of fluctuations
in atmospheric levels of organic chemicals is larger than the corresponding variations in trace
elements and sulfur discussed above, suggesting the importance of local combustion sources. Air
concentration data were not available for PCBs.
Concentrations in Precipitation. The overall volume-weighted mean concentrations of
trace elements in precipitation collected at the three sites range from 0.03 //g/L for cadmium at
Elms to 14.6 //g/L for iron at Haven Beach. For lead, the range of overall volume-weighted mean
concentrations was between 0.42 and 0.52 //g/L at the three sites. The relative proportion of trace
elements in precipitation is nearly identical to that in the Chesapeake Bay aerosol particles,
confirming that aerosol scavenging is the source of trace metals to wet deposition. Trace metal
wet depositional fluxes are highly variable, changing more than ten-fold between consecutive
months with little apparent seasonal dependence. This variability, which was similar at each of
the three sites, results not only from fluctuations in the atmospheric inventories of trace metals,
but also from changes in the amount of precipitation. On an annual basis, the volume-weighted
mean concentrations of most trace metals did not systematically vary between the summer of
1990 and fall of 1993, again suggesting that these rural sites were most strongly influenced by the
same regional background signal throughout the study.
While individual precipitation events result in spikes in trace metal deposition at one site
that are not observed at the other two locations, these isolated events average out over the year.
Annual volume-weighted mean concentrations of trace metals in precipitation are generally
within a factor of two among the three sites, with no clear systematic spatial trend observed for
all metals.
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Overall volume-weighted mean concentrations of PAHs in precipitation ranged from 0.3
ng/L for anthracene and dibenz[a,/z]anthracene at the Havens Beach site to 9 ng/L for pyrene at
the Elms site. Volume-weighted mean concentrations for total PCBs were 1.1 and 0.9 ng/L at the
Elms and Haven Beach sites (collected from June 1990 through September 1993), and 0.35 ng/L at
the Wye site (collected from January to September 1993). As was observed for trace metals, wet
depositional fluxes of organic contaminants varied considerably with time, and were dominated
by episodic spikes at each location. Extremely high concentrations of some analytes, including
pyrene, that were measured in both air and precipitation at the Elms site in the summer of 1990,
may have resulted from local vegetation burning. Unlike PAH levels in the atmosphere,
concentrations in precipitation did not systematically vary with season. The enrichment at the
Elms site is especially pronounced for higher molecular weight PAHs, suggesting a local
combustion source (e.g., wood burning for residential heating).
Concentrations of organic contaminants in precipitation measured in this study are
consistently lower than those observed in the Great Lakes region (see Figure IV-18). For
example, PAH concentrations in precipitation at the Chesapeake Bay sites are one-third to one-
half as high as at the three IADN sites located at rural, shoreline sites on Lakes Ontario,
Michigan, and Superior (Gatz et al. 1994). In contrast, levels of the same PAHs in the air over
Chesapeake Bay are equal to or perhaps higher than those measured over the Great Lakes.
Whether the apparent enrichment in PAHs in Great Lakes precipitation relative to that in the
Chesapeake Bay region, as shown in Figure IV-18, is due to more efficient scavenging by
precipitation in the colder, relatively drier Great Lakes region, or simply reflects methodological
differences between the two networks, is unclear.
Wet and Dry Aerosol Depositional Fluxes. Using CBADS data, researchers calculated
depositional fluxes (see Baker et al. (1997) for methodologies). Because these "depositional
fluxes" are actually gross fluxes directly to the water surface and do not account for net gas
exchange across the air-water interface, the term "deposition rates" is used in the remainder of
this discussion in place of "depositional fluxes" to be consistent with the rest of the report in the
use of the term "flux."
Total annual deposition rates in 1992 ranged from 0.07 mg/m2 for cadmium at the Wye
site to 121 mg/m2 for aluminum at the Elms site; the highest annual deposition rate for lead was
1.34 mg/m2 at the Wye site. Not surprisingly, dry aerosol deposition comprises the majority of
the total deposition rate for the soil elements aluminum and iron, which occur on coarse
particles. Wet deposition contributes between one-third and one-half of the total depositional
rate of the remaining trace elements. Naturally, spatial trends in total deposition result from
variation in precipitation chemistry and amount, and the trace element inventories associated
with aerosol particles (given the considerable uncertainty in the dry aerosol deposition
calculation, the same deposition velocity was used at each site). Although a distinct north to
south trend in precipitation amount occurred in 1992 (100,107, and 122 cm, respectively), total
annual deposition rates were remarkably similar among the three stations. Total deposition rates
were also very similar between years, again indicating that the relatively rare spikes in
concentration are dampened against the chronic regional background signal.
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FIGURE IV-18
Comparison of 13 PAHs and Total PCBs in Precipitation (1992) from Chesapeake Bay and Great Lakes Sampling Sites
o>
^
c
o
O
0)
o>
Source: Baker et ©I. 1998 (Chesapeake Bay) and Gatz et al. 1994 (Great Lakes).
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CHAPTER IV
CHESAPEAKE BAY
For PAHs, total annual deposition rates for 1992 range from 0.2//g/m2for anthracene at
the Wye site to 10.8 //g/m2 for benzo[b]fluorathene at the Elms site.12 Both wet deposition and
dry aerosol deposition contribute to total PAH deposition, with dry aerosol deposition becoming
relatively more important for the higher molecular weight, less volatile compounds. Total
deposition rates for PAHs decrease with time during this study, with the lowest rates occurring
during the first nine months of 1993. While some of this decrease is attributed to beginning with
anomalously high measurement in the summer of 1990, decreases in both wet and dry aerosol
deposition rates continued between 1992 and 1993. The total annual deposition rate for total
PCBs is about 3.5 //g/m2, with approximately equal contribution from wet and dry aerosol
deposition.13
Overall, total annual deposition rates for PAHs and PCBs are generally within 50 percent
among the sites. Given the uncertainty in the dry aerosol deposition estimates, this percentage
indicates little spatial variability when integrating over annual cycles. However, this study did
not specifically address the possible influences of urban areas, such as the cities of Baltimore,
Washington, and Norfolk, on atmospheric deposition, which may be important.
To place the atmospheric deposition rates calculated in this study in perspective, they are
compared to similar estimates made for the Great Lakes region (Figure IV-19). Wet deposition
rates for lead and arsenic are almost three times higher in the Great Lakes than in Chesapeake
Bay, despite significantly less rainfall (80 versus 110 cm/year); wet deposition rates for cadmium
are similar for both regions. Wet deposition rates for PAHs and total PCBs are fairly similar
between the two regions, as higher concentrations in Great Lakes precipitation (see Figure IV-18)
are offset by lower precipitation amounts. Dry aerosol deposition rate estimates are higher in the
Chesapeake region, especially for organic contaminants.14 In addition, measured aerosol-bound
organic concentrations were generally higher than the values used in the Great Lakes dry aerosol
deposition calculations (Eisenreich and Strachan 1992). Despite the differences, estimated
atmospheric deposition rates are generally within a factor of two between the Chesapeake Bay
and the Great Lakes regions, which, given the numerous opportunities for error in these
measurements and calculations, is quite good agreement.
12 Because the "fluxes" in this study are actually gross fluxes directly to the water surface, these data do not take into
account exchange of gaseous organic contaminants across the air-water interface. Other recent studies have shown
that this is the dominant atmospheric deposition process for semi-volatile organic contaminants, including PCBs (Baker
and Eisenreich 1990; Achman et al. 1993) and low molecular weight PAHs (Nelson et al. 1995). In those studies, the
net direction of exchange is often from the water to the air and diffusive gas exchange is large enough to offset wet
deposition and dry aerosol deposition.
13 Because aerosol particle-associated PCBs were present below analytical detection limits, estimates of PCB dry
deposition were made using an aerosol PCB level calculated from the measured gaseous PCB concentration and the
Junge-Pankow sorption model (Pankow 1987; Leister and Baker 1994).
14 This is due, in part, to the choice of deposition velocities used for the two studies (0.2 cm/sec for all species in the
Great Lakes, 0.26 cm/sec for trace elements and 0.49 cm/sec for organics in the Chesapeake Bay). All of these values
are within the generally accepted range for dry aerosol deposition velocities.
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CHESAPEAKE BAY
FIGURE IV-19
Comparison of Chesapeake Bay and Great Lakes Atmospheric Depositional Fluxes
Lead Cadmium Arsenic Total PCBs PhenanthrenB PyrenB BBnzo(a)pyrene
Source: Baker et al. 1996 (Chesapeake Bay) and Eisenreich and Strachan 1992 (Great Lakes).
CHESAPEAKE BAY Toxic CONTAMINANT ATMOSPHERIC LOADINGS
To estimate the annual baywide loadings of trace elements and organic contaminants to
the Bay, the annual site-specific wet and dry aerosol deposition rates were averaged and the two
average rates were multiplied by the surface area of the Bay. Uncertainties in these loading
estimates are likely, on the order of a factor of two, mainly due to the inability to estimate dry
aerosol loadings on a finer temporal resolution.
Baywide atmospheric loadings of aluminum and iron are estimated at 1,340,000 and
799,000 kg/year, respectively (see Table IV-9). Loadings of trace elements range from 1,110
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CHAPTER IV
CHESAPEAKE BAY
kg/year for cadmium to 49,400 kg/year for nickel; lead loadings are estimated at 12,500 kg/year.
Loading estimates are generally similar for 1991 and 1992, except for nickel and zinc due to
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CHESAPEAKE BAY
TABLE IV-9
Annual Atmospheric Loadings of Trace Metals and Organic Contaminants
to the Chesapeake Bay3
Pollutant
Aluminum"
Arsenic
Cadmium
Chromium
Copper
Iron
Manganese
Nickel
Lead
Selenium
Zinc
Total PCBs
Wet Deposition
(kg/year)
137,000
607
867
1,026
5,575
132,800
13,200
7,185
5,440
1,390
26,000
13
Dry Deposition
(kg/year)
1,200,000
1,050
240
2,030
3,620
666,000
13,600
6,160
7,080
2,930
22,800
20
Total Deposition
(kg/year)
1,340,000
1,660
1,110
3,060
9,200
799,000
26,800
13,300
12,500
4,320
49,400
37
PAHs
Anthracene
Benz(a)anthracene
Benzo[a]pyrene
Benzo[6]fluoranthene
Benzo[e]pyrene
Benzo[fl>/i;]perylene
Benzo[/c]fluoranthene
Chrysene
Dibenz[a/i]anthracene
Fluoranthene
Fluorene
lndeno[123crf]pyrene
Phenanthrene
Pyrene
6
9
17
36
21
19
22
29
7
70
16
20
63
75
6
34
36
98
67
75
65
85
16
119
12
78
92
109
13
44
53
134
88
94
88
114
22
189
27
98
155
184
a To estimate annual baywide loadings of elements and organic contaminants to the entire
Chesapeake Bay, the annual site-specific wet and dry aerosol fluxes were averaged and
these two average fluxes were multiplied by the surface area of the Bay.
b Contribution of aluminum is considered to be entirely from natural sources (i.e., not emitted
through human activities).
Source: Baker et al. 1997.
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elevated wet deposition measured at the Haven Beach site in 1992. Loadings of PAHs range
from 13 kg/year for anthracene to 189 kg/year for fluoranthene. Total PCB loadings are estimated
to be 37 kg/year. Interestingly, for many of the pollutants in Table IV-10, wet deposition and dry
aerosol depositional fluxes appear to decrease between 1991 and 1992. Whether this reflects a
real inter-annual variation or simply results from aggregating measurements from different
locations is unclear.
To place these loadings in perspective, they are compared in Table IV-10 to recent
estimates of trace metal and organic contaminant loadings delivered to the Chesapeake Bay by
the Susquehanna River (Conko 1995; Foster 1995; Godfrey et al. 1995). The Susquehanna River is
the largest tributary of the Chesapeake Bay, supplying approximately 60 percent of the
freshwater inflow to the estuary. Annual riverine loadings of dissolved and particulate trace
metals and organic contaminants were determined by analyzing flow-weighted samples
collected at Conowingo, Maryland, between February 1994 and January 1995 (Conko 1995; Foster
1995). Atmospheric deposition directly to the surface waters of the Chesapeake Bay supplies
PAH loads that are comparable to or greater than the loads of dissolved PAHs delivered by the
Susquehanna River (Table IV-10). Particulate-bound organic contaminants discharged from the
river dominate the loading of PAHs, with a large contribution from the high sediment burden
carried by the river during high flows. Dissolved total PCB loads from the river are
approximately three times those from the atmosphere. Atmospheric depositional fluxes of
several elements, including lead, cadmium, and chromium, are within a factor of two of the
dissolved load from the Susquehanna River. Again, particulate metal loads from the river
dominate over both dissolved riverine loads and atmospheric deposition.
While it is interesting to compare the relative importance of riverine and atmospheric
sources of trace elements and organic contaminants to the Chesapeake Bay, the results should be
carefully interpreted. While the Susquehanna River delivers large quantities of these substances
to the Bay, much of this load is removed in the northern extreme of the Bay (Helz and Huggett
1987) and is delivered episodically during high river flows. Whether particulate-bound metals
and organic contaminants are broken down in forms that can be taken up by aquatic organisms
is quite unclear. In contrast, atmospheric deposition directly to the water's surface supplies these
toxics directly to the water column, without any comparable zone of efficient removal. However,
it has recently been suggested that combustion-derived PAHs associated with aerosol particles
washed into the surface waters by precipitation also may not be broken down (McGroddy and
Farrington 1995). Finally, the distinction between riverine and atmospheric loadings is not clear.
Some fraction of the pollutant input from the tributaries results from deposition of atmospheric
pollutants to the watershed, with subsequent transmission through the vegetation and soil layers
into surface waters (i.e., indirect loading); however, this input cannot yet be quantified.
AREAS OF UNCERTAINTY AND WORK UNDERWAY
Building on the existing CAA requirements, the Chesapeake Bay Program's state and
federal partners will focus their efforts on implementation of the Chesapeake Bay Basinwide
Toxics Reduction and Prevention Strategy commitment to "establish a more complete baseline
and source identification for atmospheric deposition...and set a reduction target from that
baseline to be achieved over the next decade" (Chesapeake Executive Council 1994). However,
there are several remaining areas of uncertainty to be addressed related to atmospheric
deposition of toxic contaminants to Chesapeake Bay. Two significant ones are:
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CHESAPEAKE BAY
TABLE IV-10
Relative Importance of Sources of Trace Metals and Organic Contaminants to Chesapeake Bay
Pollutant
Aluminum
Arsenic
Cadmium
Chromium
Copper
Iron
Manganese
Nickel
Lead
Zinc
Total PCBs
Susquehanna River Load (kg/year)'1
Dissolved
2,560,000
12,600
2,130
4,130
47,800
4,100,000
3,290,000
121,000
6,530
77,900
97
Part icu late
64,800,000
ND
26,700
111,000
151,000
40,000,000
1,530,000
65,200
38,600
360,000
68
Atmospheric
Deposition Load
(kq/ypar)b
1,340,000
1,660
1,110
3,060
9,200
799,000
26,800
13,300
12,500
49,400
37
PAHs
Benz[a]anthracene
Benzo[a]pyrene
Chrysene
Fluoranthene
Fluorene
Phenanthrene
Pyrene
12
5
15
108
37
63
104
364
436
316
1,020
85
388
925
44
53
114
189
27
155
184
a Annual loads entering the Chesapeake Bay via the Susquehanna River, measured at Conowingo, Maryland, between
February 1994 and January 1995 by Foster (1995) for organic compounds and Conko (1995) for metals.
b Total atmospheric deposition loads directly to the surface of the Chesapeake Bay as measured by CBADS.
Source: Baker et al. 1997.
Dry Deposition. Dry deposition is viewed as an important mechanism by which chemical
contaminants are deposited onto the Bay's tidal surface waters and surrounding
watershed. As is the case with nitrogen, there are no widely accepted
techniques for direct measurement of dry deposition fluxes of metal or organic
contaminants. Although no direct measurements of dry deposition directly to the Bay
exist, depositional fluxes have been estimated based on a particle-size-dependent
deposition velocity function applied to direct measurements of aerosol concentrations of
metals and organic chemical contaminants. Given the absence of direct measures of dry
deposition fluxes, there is much uncertainty associated with these loading estimates.
Transport through the Watershed. Atmospheric deposition of a pollutant can be a direct
input to the Bay surface waters or can be transported from the watershed by surface
water and groundwater to the Bay. Transported loads are a component of the total
fluvial (i.e., surface water) input from the watershed to the Bay. The degree of landscape
retention for a given substance is related to the geomorphology, land use, basic
hydrological characteristics unique for each watershed, and soil chemistry. Limited
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CHESAPEAKE BAY
studies to date suggest that the degree of watershed throughput is relatively small (< 30
percent of the rate of rainfall volume). However, evidence to date suggests that
watersheds serve as a "reservoir" for atmospherically deposited metals; organically
bound metals are sequestered but may be episodically mobilized by acidic precipitation.
Because of the relatively large watershed to open water surface area ratio typical of
coastal plain estuaries such as Chesapeake Bay (15:1), recent estimates for nitrogen and
trace elements suggest that the indirect atmospheric loading may be as significant as the
direct input. Thus, while it has been possible to quantify direct atmospheric flux with a
fair degree of confidence, one of the primary uncertainties associated with resolving the
total atmospheric loading to Chesapeake Bay is in gauging the indirect loading as it
relates to the watershed transmission/retention for the myriad of sub-basins (Valigura et
al. 1995).
To further improve existing estimates of the relative atmospheric deposition contribution
to total chemical contaminant loadings to Chesapeake Bay, the following work is underway. In
1993, the University of Delaware, in cooperation with the U.S. Geological Survey, initiated a pilot
study to investigate the transport of atmospherically deposited trace elements through a pristine,
forested watershed in the headwaters of the Potomac River (Bear Branch). This study, funded by
the Maryland Department of Natural Resources' Power Plant Research Program, has the
following specific objectives: (1) to accurately determine the wet and dry atmospheric trace
element loads into the watershed, (2) to compare the total atmospheric load versus fluvial output
of trace metals and (3) to estimate the transport of atmospherically deposited trace elements
through the watershed relative to the trace metals naturally relapsed during weathering of the
soil and rock within the study area. The Bear Branch watershed was chosen as it has been well-
characterized hydrologically, is representative of the land use in the Potomac basin (60 percent of
which is forested), and possesses an unreactive quartzite lithology which simplifies its
geochemical weathering behavior. Further watershed transmission studies began in the spring
of 1996 in the Appalachian Plateau of Western Maryland. While the results of these studies will
represent an initial attempt to quantify the watershed retention/transport of atmospheric loads,
further work is needed to extend the study to other regions with differing land
use/geomorphology, in order to accurately determine an integrated, baywide watershed
transport factor.
The next section describes programs in other coastal waters, as well as research relevant
to atmospheric deposition in these coastal waters.
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CHAPTER IV
COASTAL WATERS
IV.D Coastal Waters
As stated previously, section 112(m) designates "coastal waters" as EPA's National Estuary
Program (NEP) and NOAA's National Estuarine Research Reserve System (NERRS) estuaries.
These two programs and EPA's Gulf of Mexico Program are the three significant coastal waters
programs, outside the Chesapeake Bay Program, established in the last decade. Although the
Gulf is not designated by name under section 112(m) of the CAA, 11 estuaries in various locations
spanning the Gulf coastline are either NEP or NERRS (current or proposed) designated sites and,
thus, are designated Great Waters.
The NEP, NERRS, and Gulf of Mexico programs differ in purpose and procedure, but
they all serve to protect and restore the nation's valuable coastal water resources. The remainder
of this section provides background information on each of these programs, followed by a
discussion of studies of atmospheric deposition to coastal waters and future research needs.
National Estuary Program
Congress established the National Estuary Program (NEP) in 1987 under section 320 of
the Clean Water Act. Through the NEP, states nominate estuaries of national significance that
are threatened or impaired by pollution, development, or overuse. EPA evaluates the
nominations and selects those estuaries for which there is evidence of political support, citizen
and government involvement (local, state, regional, federal), and available scientific and
technical information to address the identified problems. For the selected estuaries, EPA
convenes management conferences with representatives from all concerned groups (e.g.,
industry, agriculture, environmental organizations, state agencies) to more fully characterize
problems and seek solutions through a collaborative decision-making process. Through these
conferences, Comprehensive Conservation and Management Plans (CCMPs) are developed, for
which EPA provides up to 75 percent of the funding. Each management conference must
complete development of the CCMP within three to five years of the date the conference was
convened. Upon approval of the CCMP, action plans are carried out by implementation
agencies involved with development of the plan.
The purpose of the NEP is to identify nationally significant estuaries, protect and
improve their water quality, and enhance their living resources. The NEP currently includes 28
estuaries (individually called NEPs) representing a wide spectrum of environmental conditions
(see Figure IV-20). Because there are over 150 estuaries in the United States and only a small
fraction can be targeted for action through the NEP, the NEP is intended to act as a national
demonstration program, such that results and lessons learned in the NEP estuaries are shared
and applied by parties concerned with other estuaries throughout the country. It should be
emphasized that the NEP is a management program rather than a research program and relies
on the research of other agencies and institutions to support its work. The development of
support networks and cooperation between local, state, regional, and federal agencies is one of
the program's greatest assets.
Several NEPs have identified atmospheric deposition of pollutants as a concern to the
health of their estuaries. These NEPs have either initiated studies on the contribution of
atmospheric deposition to annual loadings for nitrogen and/or other pollutants or expressed
serious interest to EPA in conducting such projects. Nine NEPs submitted proposals to EPA in
early 1996 for funding under section 112(m) of the CAA. To date, only two NEPs (Tampa
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FIGURE IV-20
Locations of NEP and NERRS Sites
Columbia, WA and OR
Tillamook Bay, OR
South Slough, OR
San Francisco Bay, CA'
Elkhorn Slough, CA
Casco Bay, ME
Wells, ME
y, NWf.New Hampshire Estuaries. NH
Mass./Cape Cod Bays, MA
"'jquoit Bay, MA
.'Buzzards Bay, MA
irragansett Bay, Rl
mg Island Sound, CT & NY
--icBay, NY
!W Jersey Harbor, NY &NJ
North Inlet-Winyah Bay, SC
ACE Basin, SC
North Carolina, NC
North Carolina Coastal
Sanctuaries
East Coast Florida, FL
Indian River Lagoon, FL
• EPA National Estuary Program (NEP) Site
• NOAA NERRS Designated Site"
A NOAA NERRS Proposed Site"
D EPA NEP site and NOAA NERRS Designated Site
D EPA NEP site and NOAA NERRS Proposed Site
** NOAA—National Oceanic and Atmospheric Administration
NERRS—National Estuarine Research Reserve System
Bay, FL
San Juan Bay, PR
Jobos Bay, PR
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COASTAL WATERS
Bay and Galveston Bay) have received funding under section 112(m) to conduct such work.
Other NEPs (Casco Bay, Delaware Bay, Long Island Sound, Massachusetts Bays, and Peconic
Bay) have initiated exploratory studies funded by their own program and other sources.
Atmospheric deposition research related to the NEPs is discussed later in this section.
National Estuarine Research Reserve System
Another program established to recognize the importance of estuaries is the National
Estuarine Research Reserve System (NERRS), which was created by Congress in 1972 under the
Coastal Zone Management Act and which operates under the authority of NOAA. The mission
of NERRS is to establish and manage, through the cooperation of federal, state, and community
efforts, a national system of estuarine research reserves that are representative of various regions
and estuary types in the United States, in order to provide opportunities for long-term research,
education, and stewardship.
The process for designating and maintaining a NERRS site includes five main activities,
all of which may be partially funded by NOAA: (1) predesignation phase (includes selection of
the site by the state and, after approval of the site by NOAA, preparation of a draft and final
management plan and environmental impact study and completion of basic characterization
studies); (2) acquisition of land and development activities; (3) after designation as an NERRS
site, implementation of research, educational, and research programs detailed in the research
reserve management plan; (4) estuarine research and monitoring; and (5) educational and
interpretive activities.
Currently, 22 areas are designated as NERRS sites, including portions of Chesapeake Bay
and associated lands in Maryland and Virginia (see Section IV.C for a detailed discussion of
Chesapeake Bay). Six additional NERRS sites have been proposed or are in the beginning stages
of development. See Figure IV-20 for the location of the NERRS estuaries.
Studies on the direct contribution of atmospheric deposition to NERRS waters are limited
at this time. Available information on atmospheric deposition research related to NERRS waters
is presented later in this section. For example, the indirect contribution of atmospherically
deposited nitrogen to Waquoit Bay, Massachusetts, through its watershed has been estimated
and modeled as part of the multi-year Waquoit Bay Ecological Risk Assessment Case Study
(NOAA and MA DEM 1996; U.S. EPA 1996f).
Gulf of Mexico Program
The Gulf of Mexico is a very important resource to all of North America. Its surface area
is about 1,603,000 km2, large enough to cover one-fifth of the continental United States. The U.S.
portion of the Gulf's shoreline measures over 2,500 km from the Florida Keys to the Rio Grande.
Taking into account the shoreline length of all the bays, estuaries and other coastal features of
the Gulf, its effective shoreline length is about ten times that amount. The 21 major estuaries
along the Gulf coast account for 24 percent of all estuarine area in the 48 contiguous states, and
55 percent of the marshes. The watershed of the Gulf includes more than two-thirds of the
continental United States (plus one-half of Mexico and parts of Canada, Guatemala, and Cuba),
with the Mississippi River watershed alone draining about 40 percent of the continental United
States.
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The Gulf of Mexico Program (GMP) was established in 1988 in response to citizens'
concerns over declines in the Gulf's fish, shellfish, and wildlife; the quality of life in many coastal
communities; the need to protect the remaining valuable resources and prevent problems before
they occur; and to forge a positive relationship between ecological health and economic vitality
of the Gulf region. The GMP is a unique organization that involves representatives from
government agencies (federal, state, and local), business and industry, non-profit organizations
and educational institutions, and interested individuals in the process of setting environmental
goals and implementing actions to achieve those goals. The aim is to foster coordination and
cooperation among these organizations in order to reduce costs and coordinate actions.
The GMP is not a regulatory program, but rather an approach to environmental
protection, similar to the Chesapeake Bay Program, that is founded on the principles of:
• Partnership among government agencies, private, and non-government interests
to define and characterize concerns and implement solutions;
• Sound science and information as the basis of informed decision-making to guide
actions; and
• Public involvement to determine goals, identify solutions, and generate the
consensus needed for action.
Since its beginning, the GMP has made significant progress in effectively involving a
broad spectrum of the public in defining goals and objectives and in characterizing fundamental
issues. The fundamental goals of the GMP are to:
• Protect human health and the food supply;
• Maintain and improve Gulf habitats that support living resources (fish, shellfish,
and wildlife); and
• Maintain and enhance the sustainability of the Gulf's living resources.
In the past few decades, the Gulf of Mexico has been degraded, largely due to nutrient
enrichment and habitat loss. The contribution of atmospheric nitrogen to nutrient enrichment is
not well understood and is possibly a significant concern. Fed by nutrient-enriched waters of the
Mississippi River, a large area of near-bottom waters commonly become depleted in oxygen, or
hypoxic. At its peak, this area (known as the "hypoxic zone") can extend over a 18,192 km2area
from the coastal waters of the Mississippi River Delta of Louisiana to those of eastern Texas.
Stresses to the benthic (bottom-dwelling) community have been observed in this zone, including
mortality of larger non-swimming benthic organisms. This and other possible disruptions to the
food chain threaten to affect the commercial and recreational fish species within the hypoxic
area. In addition to the Louisiana Shelf hypoxic zone, 18 other coastal areas in the Gulf have
experienced hypoxia due to increasing nutrient concentrations or loads. Evaluation of
atmospheric deposition of pollutants to the Gulf is discussed below, including research in NEPs
located in the Gulf, as well as two studies conducted in the Gulf as a whole.
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Studies of Atmospheric Deposition in NEP and Other Coastal Waters
Nitrogen Loadings to Coastal Waters
At least 40 studies around the world, the majority
of which have been published since 1990, have
addressed at least the direct loading component of
atmospheric nitrogen loadings. However, the
measurement and modeling techniques used vary
considerably among individual studies, making
comparisons difficult. Table IV-11 presents a summary
of selected studies performed along the East and Gulf
coasts of the United States that are comparable in
broad terms. The two criteria for selecting these
studies were that the study results were either
published in a credible peer-reviewed journal or
advocated by a major management organization (e.g.,
an EPA NEP). These studies can be divided into two
groups: those that considered both direct and indirect
nitrogen loads and those that considered only direct
loads. Data from these studies show that, in general,
the amount of atmospheric nitrogen input is related to
the size of the waterbody and its watershed. To some
extent, the percent load from atmospheric deposition is
influenced by whether both direct and indirect
deposition were considered.
Municipal and industrial
wastewater discharges and urban
runoff/storm sewer inputs have
historically been considered the largest
sources of pollutants to coastal waters.
Recently, however, researchers have
begun to investigate the role of
atmospheric deposition as a source of
pollutants in a coastal waters (e.g., Paerl
1985,1993; Scudlark and Church 1996).
Assessing the impact of atmospheric
deposition of pollutants has become a
priority for many NEPs and other coastal
watershed protection programs. There is
a clear need to characterize the types,
quantities, and sources of pollutants that
are being directly and indirectly
deposited from the atmosphere into these
estuaries. Recent studies on atmospheric
deposition to coastal waters are discussed
briefly below and are presented in Tables
IV-12 and IV-13. Data as of December
1995 on the contribution of atmospheric
deposition to nitrogen loadings to Chesapeake Bay and other coastal waters are presented in
Table IV-11; in this table, information is presented first for Chesapeake Bay and a few related
tributaries, followed by other coastal waters in descending order of tidal water area. Data on the
contribution of atmospheric deposition to the loadings of toxic pollutants in coastal waters are
presented in Table IV-12; the coastal waters are listed in geographical order clockwise from the
northeast coast to the northwest coast. In general, the studies discussed below have evaluated
the relative contribution of nitrogen and other pollutants of concern, and do not attempt to
identify the particular emission sources contributing to this pollution.
As mentioned above, research on atmospheric deposition to Tampa Bay, Florida, and
Galveston Bay, Texas, has been conducted under the Great Waters program. The Tampa Bay
and Galveston Bay studies are discussed first, followed by a description of other studies of
atmospheric deposition to NEP estuaries (i.e., those that have been funded through sources other
than EPA's Great Waters program). Initial observations from these studies suggest that direct
and indirect loadings from air deposition may be significant sources of nitrogen and toxic
pollutants to coastal waters.
Tampa Bay. As recently as 1991, atmospheric deposition of nitrogen, air toxics, and other
pollutants was assumed to have a minimal effect on water quality in Tampa Bay. However,
based on a methodology developed by the Environmental Defense Fund (Fisher et al. 1988),
early calculations provided an early indication of likely nitrogen loadings from atmospheric
deposition in Tampa and Galveston Bays.
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TABLE IV-11
Estimates of Atmospheric Nitrogen Loadings to Selected Coastal Waters'
(in millions of kg)
Coastal Water
Chesapeake Bay (MD/VA)
Rhode River (MD)
Choptank River (MD)
Patuxent River (MD)
Potomac River (MD)
New York Bight (NY/NJ)C
Albemarle-Pamlico Sound (NC)
Long Island Sound (NY/CT)
Massachusetts Bays (MA)
Delaware Bay (DE)
Tampa Bay (FL)
Guadalupe Estuary (TX)
Narragansett Bay (Rl)
Newport River Coastal Waters (NC)
Sarasota Bay (FL)
Delaware Inland Bays (DE)
Flanders Bay (NY)
Waquoit Bay (MA)
Surface Area (km2)
Watershed
165,886
33
1,779
2,393
29,940
50,107
59,197
43,481
—
36,905
6,216
—
4,708
340
524
800
83
-70
Tidal Waters
11,400
4.9
361
137
1,210
38,900
7,754
4,820
3,700
1,846
1,031
551
328
225-1,600
135
83
39
~8
Deposition to
Watershed
175
—
—
—
—
69
-39
43
—
53
—
—
4.2
—
—
—
—
—
0.062
Direct
Deposition to
Tidal Waters
16
0.005
0.57
0.22
1.9
54
3.3
5
1.6-6
3
1.1
0.31
0.3
0.4
0.095-0.68
0.16
0.28
0.027
—
Indirect Atmos.
Load From
Watershed
29
—
—
—
—
8
6.7
6
—
5
—
—
0.3
—
—
—
—
—
0.0065
Total
Atmospheric
Load
45
0.005
0.57
0.22
1.9
62
10
11
1.6-6
8
1.1
0.31
0.6
0.4
0.095-0.68
0.16
0.28
0.027
0.0065
Total Load
From All
Sources
170
0.012
1.54
12.6
35.5
164
23
60
22-30
54
3.8
4.2-15.9
5
9
0.27-0.85
0.6
1.3
0.36
0.022
% Load from
Atmosphere
27
40
37
13
5
38
44
20
5-27
15
28
2-8
12
4
36-80
26
21
7
29
Referenceb
5
6
11
11
11
1
4
3
15
2
14
13
1
12
4
10
9
8
7
a Estimates as of December 1995.
b(1)Hingaetal. 1991; (2) Scudlark and Church 1993; (3) Long Island Sound Study; (4) Paerl and Fogel 1994; (5) Linker et al. 1993; (6) Correll and Ford 1982; (7) Valiela etal.
1996; (8) Peconic Bay NEP; (9) Delaware Bays NEP; (10) Sarasota Bay NEP 1995; (11)Boynton etal. 1995; (12) Nixon et al. 1995; (13) Brocket al 1995; (14) Tampa Bay NEP,
Zarbock et al. 1994; (15) Massachusetts Bays NEP 1996.
c New York Bight extends from Cape May, New Jersey, to Long Island Sound.
Source: Adapted from Valigura et al. 1996.
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TABLEIV-12
Studies of Atmospheric Loadings of Toxic Pollutants to NEP Coastal Waters
Coastal Water
Massachusetts Bays (MA)
Narragansett Bay (Rl)b
New York-New Jersey Harbor
Estuary and Bight
(NY/NJ)
Delaware Bay (DE/NJ/PA)b
Tampa Bay (FL)
Galveston Bay (TX)
Santa Monica Bay (CA)
Pollutants of Concern
Evaluated3
PAHs, PCBs, cadmium, lead,
mercury
PCBs, PAHs
Cadmium, lead, mercury, PCBs,
dioxins, PAHs, various pesticides
Lead, mercury, PCBs, various
pesticides, volatile organic
compounds (VOCs)
Cadmium, lead, mercury,
chlordane, DDT, dieldrin, PCBs,
PAHs
Cadmium, lead, mercury,
chlordane, DDT, dieldrin, PCBs,
PAHs
PAHs, PCBs, selected pesticides,
lead, cadmium, mercury
PAHs, metals, chlorinated
organics
Relative Contribution of Atmospheric Deposition
for the Great Waters Pollutants of Concern
Direct atmospheric deposition estimated to contribute: PAHs,
9-46%; PCBs, 28-82%; cadmium, 17-31%; lead, 39-45%;
mercury, 4-13%.
Direct atmospheric deposition found to contribute 3% of
PCBs and 12% of PAHs.
Atmospheric deposition identified as a significant contributor
to total pollutant loading for lead (39-54%), but may have
been over-estimated. For other pollutants, either
atmospheric deposition was insignificant or estimates were
not developed.
Atmospheric deposition (both direct and indirect) found to be
a significant source of mercury (80%) and PCBs (34%). For
lead, atmospheric deposition contributed less than 5%. For
other pollutants, either atmospheric deposition was
insignificant or estimates were not developed.
Direct and indirect atmospheric deposition identified as a
significant contributor of cadmium (46%), lead (12%), and
PCBs0, but not a significant source of chlordane, DDT,
dieldrin, or mercury (1% each). Estimates for PAHs were not
developed.
On-going study - no results yet.
On-going study - no results yet.
Atmospheric deposition was estimated to be a significant
source of lead and PAHs.
Reference
Menzie-Cura &
Associates 1991
Latimer 1997
NY-NJ Harbor
NEP 1995
Frithsen et al.
1995b
Frithsen et al.
1995a
U.S. EPA1995f
U.S. EPA1995g
SMBRP 1994
a For a discussion of other pollutants evaluated, study methods, and uncertainties, see referenced study.
b These NEPs also are NERRS designated sites.
c Estimates of PCS loadings could be made for atmospheric deposition only; therefore, a relative comparison to other sources could not be made.
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A recent study of nutrient (i.e., nitrogen and phosphorus) and suspended solids loadings
conducted for the Tampa Bay NEP suggests that direct atmospheric deposition of nitrogen to the
tidal waters of Tampa Bay is the second largest source of nitrogen entering the Bay, contributing
up to 28 percent of the total nitrogen load (Zarbock et al. 1994). The largest source of nitrogen,
according to that study, is urban storm water runoff. A portion of the nitrogen entering the Bay
from urban storm runoff represents atmospherically deposited nitrogen to impervious surfaces
such as paved roads and sidewalks. These studies prompted the Tampa Bay NEP to revise its
CCMP to consider atmospheric deposition issues.
Another study, conducted by the Tampa Bay NEP (Frithsen et al. 1995a), investigated the
contribution of atmospheric deposition relative to point sources, urban runoff, and other
nonpoint sources for specific chemical contaminants of concern. The contaminants, which were
selected based on their potential for toxic effects and their concentrations observed in sediment
samples, included: six metals (cadmium, chromium, copper, lead, mercury, and zinc); four
organochlorine pesticides (chlordane, DDT, dieldrin, and endrin); and two classes of organic
chemicals (polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)). In
addition, loadings were estimated for arsenic and iron because of the potential of these chemicals
have for environmental harm or interaction with contaminants of concern through chemical
processes. Because the study used numerous information sources, representing a wide range of
spatial and temporal conditions, a great deal of uncertainty exists regarding the absolute
estimates of atmospherically deposited chemical contaminants to Tampa Bay. Study results are
intended to establish the relative magnitudes of different classes of sources in order to set
priorities for more detailed research and monitoring activities. Some general conclusions,
however, are apparent:
• Contaminant inputs to Tampa Bay from runoff and transfer of atmospherically
deposited contaminants to the watershed (i.e., indirect loading) are approximately
two-thirds the contribution of contaminant inputs from direct deposition to tidal
waters (i.e., direct loading);
• Atmospheric deposition contributes a sizeable percentage to total annual load for
the following metals: cadmium (46%), copper (18%), chromium (13%), lead
(12%), and iron (11%);
• Atmospheric deposition of mercury is around 4 kg/yr and atmospheric deposition
of pesticides is estimated as 10 kg/yr, each representing about one percent of the
total load; and
• Atmospheric deposition is the only pathway that contributed a measurable
amount of PCBs, estimated as a minimum total load of 11 kg/yr. No estimate
could be developed for PAHs using available datasets.
Ongoing monitoring, described below, conducted by the Tampa Bay NEP, local governments,
and other collaborators will better define the spatial distribution of atmospherically deposited
chemical contaminants and nitrogen throughout the 10 major basins of Tampa Bay and its
watershed as well as the relative contributions of local, regional, and global emission sources.
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An ongoing cooperative study administered by the Tampa Bay NEP will substantially
expand air transport and deposition monitoring and modeling projects in an effort to develop
nationally recognized quantitative assessments for important air deposition parameters. Now in
its second year of operation, the Tampa Bay Atmospheric Deposition Study (TBADS) involves
EPA's Great Waters program; the local governments in Hillsborough, Pinellas, and Manatee
Counties; the Florida Department of Transportation; the Southwest Florida Water Management
District; Florida State University; a private consultant; and other organizations. TBADS will
attempt to determine: (1) what fraction of the nitrogen and toxic pollutants emitted annually by
specific sources within the Tampa Bay watershed enter the Bay waters (i.e., are deposited either
onto the water surface directly or onto the watershed and subsequently enter the Bay waters
through runoff); and (2) what are the relative contributions of local sources (i.e, inside the
watershed) versus remote sources (i.e, outside the watershed) to atmospherically deposited
nitrogen and toxic pollutants in the watershed. Projects that have been initiated to address
elements of this air deposition program include:
• Intensive daily wet and dry deposition monitoring at Gandy Site, located on
Tampa Bay's Interpeninsula, for nitrogen and toxic pollutants for an additional 12
months, yielding two years of continuous data collected and analyzed according
to AIRMoN protocol;
• Application (with the Florida State University Center for Tropical Meteorology) of
a regional air mass movement model developed by Pennsylvania State University
(Penn State/NCAR Mesoscale Model Version 5) to investigate air transport at a
coarse grid for the southeastern United States while maintaining a much higher
resolution grid over the Tampa Bay area to estimate retention times for air masses
within the watershed under different meteorological conditions;
• Integration of NOAA's Physical Oceanographic Real-Time System (PORTS)
Meteorological data collected at several over-water stations (with NOAA and the
University of Florida); and
• Intensive stormwater sampling to measure stormwater runoff, nitrogen, and toxic
contaminant concentrations and loads at up to four gaged subbasins. Data will be
used to estimate the relative contribution of atmospheric loading to stormwater
for different land use types (residential, urban, industrial, and/or urban parks); it
is expected that this transfer coefficient information will be useful not only to
Tampa Bay and Florida, but also to watersheds nationwide.
An important element of the Tampa Bay atmospheric deposition program is the participation
and coordination of local and federal government programs and state agencies with the Great
Waters program and the Tampa Bay NEP.
Galveston Bay. The Great Waters program conducted a screening atmospheric
deposition monitoring program in Galveston Bay, Texas, which was chosen as the site to
establish monitoring for the Texas Regional Integrated Atmospheric Deposition Study (TRIADS)
as a representative of a Gulf of Mexico estuary. Monitoring at the TRIADS site began in February
1995. To facilitate comparability, the sampling and analytical design of TRIADS is similar to that
of existing monitoring sites in the Great Lakes and Chesapeake Bay. The goals of this study are
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to evaluate the contribution of atmospheric deposition of selected contaminants to the Bay and
to evaluate long-range transboundary transport of contaminants. Pollutants measured include
cadmium, lead, mercury, nitrogen, PAHs, PCBs, and selected pesticides. Results from TRIADS
complement and add to data from other investigations in Galveston Bay, including studies by
the Galveston Bay NEP, EPA's Environmental Monitoring and Assessment (EMAP) program,
NOAA National Status and Trends (NS&T) program, and special urban-pollutant studies in
Houston, Texas. Data from these programs and the TRIADS data will be used to estimate the
cumulative, direct and indirect impacts of atmospheric deposition to pollution of Galveston Bay.
Although early calculations suggested that atmospheric deposition could be a significant
contributor to nitrogen loads delivered annually to Galveston Bay, the relevance of this finding
to the health of the ecosystem for Galveston Bay is not as obvious as for either Chesapeake Bay
or Tampa Bay. While all three estuaries have experienced declines in submerged aquatic vegeta-
tion (SAV), studies on SAV in Galveston Bay are limited in contrast to documented cases of large-
scale changes in other major estuaries (Pulich et al. 1991). While atmospheric nitrogen loading may
contribute to the incidence of hypoxia, other factors appear to be causing this phenomenon, which
is quite localized in Galveston Bay compared to its manifestation in the other two estuaries.
In contrast to the perceived limited biological effects from atmospheric deposition of
nitrogen, previous research has suggested that atmospheric deposition of toxic contaminants
may be affecting fish and shellfish in Galveston Bay, and thus contributing to human health risk.
A pilot study performed for the Galveston Bay NEP documented the presence of dioxins, furans,
lead, mercury, PAHs, PCBs, and pesticides in certain species of finfish and shellfish, but could not
determine the sources of these contaminants (Brooks et al. 1992). Monitoring data from the
TRIADS site detected the presence of all these chemical contaminants in air samples, suggesting
that atmospheric deposition may be a significant source (Battelle 1995). Continued monitoring
will enable scientists and managers to more fully evaluate this problem and determine the rela-
tive effect of atmospheric deposition versus point and nonpoint source inputs into Galveston Bay.
Casco Bay. The primary pollutants of concern for atmospheric deposition to Casco Bay,
Maine, include PAHs, PCBs, nitrogen, phosphorus, sulfates, pesticides, and mercury and other
trace metals. Recent sediment studies have found elevated concentrations of some pollutants (i.e.,
cadmium, lead, mercury, PAHs, PCBs, silver, and zinc) near population centers and waste dis-
charges, but also observed elevated levels in rural eastern Casco Bay away from these known
sources (Wade et al. 1995). A circulation model study of the Bay did not clearly indicate any pos-
sible sources for these pollutants, suggesting atmospheric deposition as a significant source (Pearce
et al. 1994). While elevated levels of lead found in Casco Bay sediments were relatively near poten-
tial sources, elevated levels of cadmium were found far from any known local source. A deposition
study would provide empirical verification of processes believed to be occurring at Casco Bay.
Delaware Bay. In Delaware Bay, studies have shown that direct and indirect
atmospheric deposition provide 15 percent of the annual nitrogen input, increasing to 25 percent
in late spring and early summer (Scudlark and Church 1993). The relative nitrogen loading is
slightly lower than observed in nearby Chesapeake Bay (27 percent), and much lower than in the
Delaware Inland Bays (Rehoboth and Indian River Bays) where direct atmospheric deposition
alone contributes 27 percent of the total nitrogen load (Cerco et al. 1994). The contribution to the
Delaware Bay is lower because of higher point source nitrogen loading to Delaware Bay and the
influence of a highly urbanized watershed.
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As part of a Delaware Estuary Program study to estimate contaminant inputs,
atmospheric deposition was found to be a significant source of mercury (80 percent) and PCBs
(34 percent) (Frithsen et al. 1995b). As is the case in other regions, more research is warranted on
atmospheric inputs of mercury and the resulting effects on estuarine and human health. To
evaluate the effect atmospheric deposition of mercury has on the Delaware, Rehoboth, and
Indian River estuaries, a precipitation monitoring station was established at Lewes, Delaware, in
1995 in conjunction with EPA's National Atmospheric Deposition Program Mercury Deposition
Network.
Gulf of Mexico. It is probable that
significant amounts of nitrogen are deposited
into the Mississippi River Basin via
atmospheric deposition, but there has been
little investigation conducted regarding
atmospheric nitrogen as a source of nitrogen
for the Mississippi River drainage basin.
Some basic estimates using National .. ., , ,. , ,, ,
0 attributable to the hypoxia;
Atmospheric Deposition Program (NADP)
data were provided at a Hypoxia Conference
held by the Gulf of Mexico Program in
August 1996. These estimates showed
. .... .,.,.. . , • Information and policy required for action.
significant variability in quantity of
Hypoxia Conference
A conference was convened in 1996 in
response to the hypoxia problem in the Gulf of
Mexico. Topics addressed included:
• Characterization of the hypoxiczone;
• Economic impacts and trends in fisheries
Causes of the hypoxic zone;
Sources and delivery of nutrients in the
watershed, including atmospheric deposition;
Current efforts to control nutrient loads; and
atmospherically deposited nitrogen, with a
range of 0.55 million to 3.08 million tons. This
variability is due to differing assumptions of what atmospheric nitrogen input sources should be
included, what forms of deposition should be measured (e.g., dry deposition), and what nitrogen
compounds should be analyzed (e.g., ammonium). At the high end, atmospheric nitrogen would
be on par with animal manure, ranking as the second highest source of nitrogen input to the water-
shed. At the lower end, estimated atmospheric nitrogen inputs would rank as the fifth highest
source of nitrogen input for the watershed. This wide variability in estimated quantity points to
the need for further and more refined estimates of atmospheric nitrogen inputs to the Gulf.
Long Island Sound. A chronic problem in Long Island Sound is the low oxygen levels
(hypoxia) that are observed during the summer. An early study noted that excess nitrogen
loading was a major cause of hypoxia and estimated that atmospheric loading directly to the
water surface contributed 8 percent of the total nitrogen delivered to the Sound (LIS Study 1990).
A later study produced essentially the same estimate for the total contribution of direct
atmospheric deposition, but divided it into two components: an amount from "natural" sources
(i.e., background approximating "amount believed to have been delivered to Long Island Sound
in pre-Colonial days") and an amount from "human-induced" sources (LIS Study 1994). Using
measurements of wet and dry deposition from two sites along the Connecticut shore, Miller et al.
(1993) estimated direct atmospheric loadings to Long Island Sound. The Long Island Sound
Study used these data and literature values to develop the estimates shown in Table IV-12, and
concluded that (direct and indirect) atmospheric deposition may be responsible for 17 to 24
percent of total nitrogen entering the Sound.
In the most recent study, all sources of nitrogen, including atmospheric deposition, are
divided into "natural" and "human-caused" components (Stacey 1996). This study concluded that
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CHAPTER IV
COASTAL WATERS
atmospheric deposition from human activities in the New York and Connecticut portions of the
Long Island Sound watershed accounts for 13.6 percent of the total enriched or "human-caused"
load. Further work is necessary to model relationships among air quality, direct and indirect
atmospheric deposition, and runoff concentrations to receiving waters of the Sound.
Massachusetts Bays. In one Massachusetts Bays NEP study, direct atmospheric
deposition was estimated to contribute 5 to 16 percent of total nitrogen load to Massachusetts
Bays (Menzie-Cura & Associates 1991). In another Massachusetts Bays NEP study, direct
atmospheric deposition of nitrogen was estimated to account for 6 to 8 percent of total nitrogen
loadings to the Bays (Zemba 1995). Different methodologies were used to estimate nitrogen
loadings in these two studies. The estimate by Zemba (1995) used literature values and ten years
(1981-1991) of wet deposition data from the NADP. Other studies cited by the Massachusetts
Bays NEP suggest that the contribution of atmospheric deposition may be higher, about 16 to 20
percent of total nitrogen load, excluding exchange with the Gulf of Maine (Massachusetts Bays
NEP 1996).
Atmospheric deposition is also a significant contributor of organic pollutants and trace
metals to Massachusetts Bays. Menzie-Cura (1991) estimated that direct atmospheric deposition
was a significant source of PAHs (9-46 percent), PCBs (28-82 percent), cadmium (17-31 percent),
and lead (39-45 percent). A subsequent Massachusetts Bays NEP study generally corroborated
the Menzie-Cura (1991) metal deposition results, although lead deposition rates were slightly
lower (Golomb et al. 1995). The lead deposition estimates may be lower in Golomb (1995)
because the data used in the Menzie-Cura study were obtained prior to the phase out of leaded
gasoline. Golomb (1995) also indicated that PAH deposition may have been underestimated and
that PCB concentrations were below detection limits and, therefore, atmospheric deposition rates
for PCBs were not calculated. Because PCB concentrations were below the detection limit, more
precise field measurements of wet and dry deposition of PCBs are necessary to verify the initial
estimates and to determine the relative impact of atmospheric deposition of PCBs to
Massachusetts Bays.
Peconic Bay. Nitrogen from atmospheric deposition to the Peconic River and Flanders
Bay, New York, is estimated to be about 73 kg/day, or about five percent of the total nitrogen
loading to that area (Suffolk County 1992). The impact of atmospheric deposition on
eutrophication in Peconic River and Flanders Bay is considered to be relatively small in relation
to other point and nonpoint sources. Atmospheric deposition is believed to be much more
significant in terms of relative eutrophication impacts to Peconic Estuary surface waters east of
Flanders Bay. Detailed loading estimates for these eastern areas, as well as for specific
subwatersheds, are being developed for the Peconic NEP waters, and the relative eutrophication
impacts of sources are being assessed through computer modeling.
Future Research Needs in NEP and Other Coastal Waters
Research on atmospheric deposition to coastal waters has been limited to a few areas, and
most studies have focused on identifying and determining the concentration of pollutants of
concern in water and sediment, and measuring concentrations of pollutants in precipitation.
Due to limited funding, many preliminary NEP studies are restricted to using historical data to
estimate atmospheric deposition. Some NEP studies have used a rough mass balance approach
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CHAPTER IV
COASTAL WATERS
to determine the relative loading of each pollutant to the estuary, but more precise quantitative
mass balances are needed, which require accurate and comprehensive atmospheric data.
Establishing the total contribution of pollutants and their sources is an important part of
developing and implementing CCMPs for NEPs, and the lack of knowledge about the
concentrations, deposition, and potential sources of airborne pollutants makes sound policy
formation for the estuaries difficult. The question of the magnitude of pollutant deposition from
the air has become more important as other sources of pollution to rivers, lakes, streams, and
coastal waters have been identified and significantly reduced.
Research questions for the NEP estuaries and other coastal waters include:
• What are the concentrations and loadings of pollutants that are being supplied by
atmospheric deposition?
• What are the relative contributions of these inputs to the total load of pollutants
entering the estuary?
• What are the emission sources that affect the estuaries and where are they
geographically located?
• Does atmospheric deposition (direct and indirect) of contaminants cause or
contribute to biological harm in benthic (bottom-dwelling) or pelagic (suspended,
planktonic, or water column) communities, or affect human health?
• What economically and technically feasible methods are available to effectively
reduce airborne pollutants and their effects on estuaries?
The NEP estuaries provide an excellent opportunity to evaluate the effects and
contribution of atmospheric deposition of contaminants to a varied set of ecological,
environmental, and anthropogenic conditions. The NEP also provides a "grassroots" forum for
addressing and correcting regional and national air quality issues as they pertain to our coastal
waters. Recommendations for further atmospheric deposition research in coastal waters to help
answer the above questions include:
• Utilize existing databases and ongoing work of established research programs and
coordinate research initiatives with these programs;
• Protect and enhance existing monitoring programs;
• Establish long-term water and air quality monitoring programs that incorporate
sampling for atmospheric deposition of contaminants for a subset of NEP
estuaries representing various geographical regions and environmental
conditions;
• Use sampling data from monitoring programs to track trends and spatial
variability to develop more accurate loading estimates;
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COASTAL WATERS
• Coordinate efforts between NEP estuaries and other Great Waters program
studies to identify local, regional, and national sources of airborne pollutants;
• Pursue detailed atmospheric chemistry and deposition models for estimating
atmospheric deposition to NEP estuaries;
• Develop a multi-party effort to identify and demonstrate appropriate pollution
prevention techniques;
• Apply existing atmospheric circulation models to fill in data gaps between
measured and estimated atmospheric deposition and to aid in tracing the
pollutants in the estuaries back to their probable sources; and
• Support process-related research to establish cause and effect relationships
between atmospheric deposition of contaminants and alterations of water quality,
fisheries, recreational and other economic and ecological resources of receiving
estuarine and coastal waters.
This research is needed not only to assist decision-makers for specific coastal waters, but to form
a comprehensive picture of atmospheric deposition across the United States. In addition,
coordinated use of other mechanisms, such as voluntary pollution prevention, can help control
the negative impacts of atmospheric deposition to water quality in NEP estuaries, especially at
the local and regional level.
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CONCLUSIONS AND FUTURE DIRECTIONS
This report affirms and provides added support for the findings of the First Report to
Congress that, for studied Great Waters, atmospheric deposition of toxic pollutants and excessive
nitrogen is often an important factor affecting the environmental conditions of these waterbodies
and can contribute to adverse ecological and human health effects. Moreover, the contribution
of atmospheric deposition can be significant as part of the total loading for many waterbodies.
For the fresh waters, such as the Great Lakes and Lake Champlain, metals, organic compounds,
and pesticides released into the atmosphere have been measured in significant quantities near
these waterbodies, and their deposition has been measured or calculated. For Chesapeake Bay
and many other U.S. coastal waters, the impact of atmospheric deposition is not only from toxic
pollutant releases, but also from inputs of nitrogen compounds that contribute to eutrophication
(an overabundance of nutrients in a waterbody). Significant atmospheric loadings for both
nitrogen and toxic pollutants have been determined for certain estuaries.
Since the First Report to Con-
gress, significant progress has been
made to increase our knowledge of
atmospheric deposition to the Great
Waters (see sidebar summary). As
highlighted in this report, greater atten-
tion has been placed on monitoring and
modeling atmospheric deposition at the
individual Great Waters, with many of
these studies funded or supported by
EPA's Great Waters program. Quantita-
tive information has continued to be
gathered on the atmospheric levels of
pollutants and their deposition to the
Great Waters. Monitoring studies have
been conducted to provide waterbody-
specific data on deposition and the
relative contribution of atmospheric
deposition to total loadings, as well as
to develop and improve measurement
and modeling methods. Moreover, the
findings from the investigation of one
waterbody are expected to lead to a
more informed or efficient assessment
of atmospheric deposition and its
effects for other waterbodies.
Based on the scientific
information currently available, EPA
continues to support the three broad
conclusions presented in the First Report to Congress regarding potential adverse effects, relative
atmospheric loadings, and sources of atmospheric deposition.
Progress Since the First Report to Congress
in Cooperation With the Great Waters Program
i Initiation of a comprehensive mass balance model of
Lake Michigan, for which results will estimate relative
loadings, with the methodology to be adapted and
applied to other waterbodies;
i Improved and refined source emission inventories for
pollutants of concern;
i Formal policy commitment of the U.S. and Canadian
governments to address Virtual Elimination of
Persistent Toxic Substances in the Great Lakes;
i Increased monitoring and modeling studies in progress
at the specific waterbodies;
i State-of-the-art air quality modeling of nitrogen
sources, transport, and deposition to the Chesapeake
Bay watershed;
i Increased activities at the coastal waters including
development and implementation of monitoring studies,
comprehensive pollution prevention plans, and
management programs;
i Understanding that atmospheric deposition contributes
significantly to excessive nitrogen loads in 13 of the 14
studied estuaries along the East and Gulf coasts; and
i Numerous programs and activities that are funded and
supported by the Great Waters program.
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CONCLUSIONS
4 Adverse effects (e.g., cancer and developmental effects) that the Great Waters pollutants
of concern can cause in humans and wildlife are fairly well understood. However, data
are insufficient at this time to establish the linkage between atmospheric deposition of
these pollutants and adverse effects.
4 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 characteris-
tics of the waterbody, properties of the chemical, and the kind and amount of atmo-
spheric or water discharges (airborne or waterborne).
4 Airborne emissions from local as well as distant sources contribute pollutant loadings to
waters through atmospheric deposition. Determining the relative roles of particular
sources — local, regional, national and possibly global — that contribute significant
deposition to specific waterbodies is complex, requiring careful monitoring, atmospheric
modeling, and other analytical techniques.
In addition to these conclusions, EPA also reaffirms its support for the three major
strategic themes developed in the First Report to Congress, which provide a broad scope for
recommendations for action.
(1) 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) EPA recognizes the need for an integrated multimedia approach to the problem of
atmospheric deposition of pollutants to waterbodies and will continue to pursue imple-
mentation of programs available under various federal laws to reduce the human and
environmental exposure to pollutants of concern.
(3) EPA is committed to supporting research activities that address the goals of CAA section
In this chapter, Section V.A discusses EPA's assessment of the factors listed in CAA
sections 112(m)(5)(A) through (E). This assessment is based on the scientific information
summarized in this report, as well as the findings in the First Report to Congress. Section V.B
discusses future directions and actions that EPA anticipates for the Great Waters program.
Section V.C summarizes EPA's draft determinations under section 112(m)(6), which
are being published separately in the Federal Register. EPA also must consider under section
112(m)(6) two questions concerning the adequacy of the authority under provisions of section
112 and the possible need for further standards or control measures. Under the terms of a
consent decree entered in Sierra Club v. Browner, Civ. No. 96-1680, EPA is to issue draft deter-
minations for public notice and comment by June 30, 1997, and final determinations by March 15,
1998.
4 EPA is required to determine whether the other provisions of section 112 are adequate to
prevent serious adverse effects to public health and serious or widespread environmental
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CONCLUSIONS
effects associated with atmospheric deposition of hazardous air pollutants (HAPs) to the
Great Lakes, the Chesapeake Bay, Lake Champlain, and coastal waters.
4 Based on the information available in this report and on the determination regarding the
adequacy of section 112 authority (which is specific to HAPs), EPA must also determine
whether additional emissions standards or control measures under section 112(m)(6),
beyond those otherwise authorized or required by section 112, are needed to prevent
such effects from atmospheric deposition, including effects due to bioaccumulation and
indirect exposure pathways.
V.A Reporting on the Role of Atmospheric Deposition to the Great Waters
and Specific Actions Proposed
As stated in the CAA, EPA is required to assess the contribution of atmospheric
deposition to the Great Waters on several issues (listed below). While these issues have been
discussed at length at various places in the body of this report, this section summarizes EPA's
efforts to address these five elements:
• Pollutant loadings — section 112(m)(5)(A);
• Environmental and public health effects — section 112(m)(5)(B);
• Pollutant sources — section 112(m)(5)(C);
• Exceedances of water quality or drinking water standards — section 112(m)(5)(D);
and
• Description of any necessary revisions to requirements, standards, and limitations
pursuant to the CAA and other federal laws — section 112(m)(5)(E).
Contribution of Atmospheric Deposition to Pollutant Loadings in the Great
Waters
A substantial amount of scientific information has demonstrated that atmospheric
deposition contributes to pollutant loadings in the Great Waters. In and around the Great Lakes,
studies have shown that atmospheric transport and deposition of persistent hazardous chemicals
occurs and is significant in the overall inputs to the lakes. The Great Waters program has
focused on a set of chemicals that show persistence in the environment, tendency to accumulate
in animal tissue, and toxicity to humans and other animals. Data from several studies of the
lakes' waters, sediments, fish, and wildlife, show a general decrease in concentrations of
persistent toxics during the 1970s and 1980s. These declines have resulted from many efforts
taken to reduce discharges to both air and water of potentially harmful chemicals (which
included the pollutants of concern). Also, some of these declines may be attributed to
significantly reduced use or canceled registrations of persistent pesticides in the United States.
In the 1990s, the overall picture of persistent toxics in the Great Lakes basin shows much more
gradual decline, if any (though particulars vary from lake to lake and among pollutants). Due to
limitations in historical monitoring techniques, considerable uncertainties exist for earlier data
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CONCLUSIONS
and thus, definitive conclusions about atmospheric pollutant trends are not made in this report.
Quantitative monitoring data of atmospheric concentrations and deposition of the pollutants of
concern have become available in recent years. It is anticipated that, as more data become
available, better interpretations and conclusions can be made about pollutant trends, which in
turn will better inform EPA about the extent to which additional actions will need to be taken,
with possible focus on individual pollutants. Monitoring of toxics and nitrogen compounds
(nitrates and others) has also been performed in Chesapeake Bay and other coastal estuaries and
(with a focus on mercury) in Lake Champlain.
The Integrated Atmospheric Deposition Network (IADN) is an ongoing, binational
monitoring network that assesses the magnitude and trends of atmospheric deposition to the
Great Lakes region for wet and dry deposition and net gas exchange. Results from the past few
years indicate that atmospheric deposition of some hazardous pollutants is still a concern for the
Great Lakes. In similar work, data have been collected through the Chesapeake Bay
Atmospheric Deposition Study (CBADS) on pollutant concentrations in air and precipitation. By
incorporating emissions data with these measurements, atmospheric loading rates have been
estimated. Certain trace metals appear to be deposited into the Bay as toxic contaminants.
However, information on toxic contaminant trends in the Bay is not yet available. At Lake
Champlain, researchers have been gathering information on deposition of mercury to the basin
to characterize the types of mercury deposition (gaseous, wet, and dry particulate). To date, not
enough information is available to assess trends for atmospheric mercury in the Lake Champlain
basin.
Recent studies of several coastal waters have investigated the significance of atmospheric
deposition to toxic pollutant loadings, and preliminary results show that atmospheric deposition
can contribute a significant portion of loadings to coastal waters (e.g., Tampa Bay, Delaware Bay,
Massachusetts Bays) for pollutants such as cadmium, lead, mercury, PAHs, and PCBs. For
example, atmospheric deposition of cadmium is estimated to contribute 46 percent of the total
annual load (direct and indirect) to Tampa Bay and 17 to 31 percent of the total annual load
(direct) to Massachusetts Bays. Atmospheric deposition (direct and indirect) has been estimated
to be a significant contributor of mercury (80 percent) to Delaware Bay. However, there are
several remaining areas of uncertainty to be addressed related to atmospheric deposition of toxic
contaminants to the Great Waters, including: the lack of accepted techniques for direct,
quantitative measurement of dry particulate deposition and the unknowns associated with
indirect loadings of pollutants, as they relate to watershed transmission and retention.
Information on relative loadings from air compared to other inputs of toxic contaminants
in the Great Waters is still being assessed, although advances have been made in EPA's ability to
address this issue. A comprehensive mass balance model for Lake Michigan has been initiated to
gather information on loadings from different pathways, including the atmosphere, sediment,
biota, and tributaries, as well as to study the variability in magnitude of atmospheric loadings
near more urbanized areas versus rural areas. Preliminary modeling results from this major study
are anticipated in 1998, and final results by 1999, which are expected to provide a better under-
standing of relative loadings and the movements of persistent pollutants in the environment.
Nitrogen deposition has been studied for coastal estuaries. Investigations have gathered
information on atmospheric deposition estimates as well as relative loadings to these waters.
Computer modeling studies for the Chesapeake Bay indicate that atmospheric deposition
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CONCLUSIONS
accounts for approximately 27 percent of the total annual loading of nitrogen (376 million
pounds), while 23 percent of the load comes from point source water discharges and 50 percent
from non-point sources other than air, such as fertilizers and animal wastes. Since the First
Report to Congress, additional studies have been initiated to measure nitrogen deposition in
coastal estuaries other than Chesapeake Bay (e.g., Tampa Bay, Long Island Sound, Massachusetts
Bay). For those studies that evaluated both direct and indirect deposition, the contribution of
atmospheric deposition to the nitrogen load ranges from approximately 12 to 44 percent.
To project the ultimate influence of changes in total nitrogen loadings to the Bay
(including loadings other than from the air), the Chesapeake Bay Program recently configured
the Bay Watershed Model to accept daily atmospheric loadings by land use category (i.e., forest,
pasture, cropland, and urban). The Chesapeake Estuary Model is being upgraded to simulate
basic ecosystem processes of submerged aquatic vegetation (SAV), benthic microorganisms, and
major zooplankton groups. In addition, EPA's Regional Acid Deposition Model (RADM) is being
directly linked to the Watershed and Estuary models. This new integrated model, functionally
linking the airshed, watershed, estuary, and ecosystem, is expected to be completed in mid-1997.
Some of the remaining areas of significant uncertainty in estimating atmospheric loads are:
nitrogen retention in watersheds, the relative loadings of ammonia and organic nitrogen
(compared to nitrate), and dry particulate deposition directly to water surfaces.
Contribution of Atmospheric Deposition to Adverse Human Health Effects or
Adverse Environmental Effects in the Great Waters
Current information on potential exposure to and effects of pollutants of concern to the
Great Waters adds greater weight to the scientific data and conclusions reached in the First
Report to Congress. Effects on fish and wildlife that are associated with exposures to these
persistent chemicals continue to be reported in research literature. At this time, it is not possible
to identify which specific individual pollutants, or defined mixtures, cause specific adverse
effects observed in the biota of the Great Waters. Even if more direct and definite links between
exposure and effect were established, the relative contribution of a pollutant from current air
deposition compared to overall loading for the waterbody still needs to be better characterized
and quantified to provide a basis for setting appropriate reduction targets. Because many of the
pollutants of concern persist for decades, current loading must be considered in light of
contamination that has come from many sources and persisted many years. Persistence also
means that while emissions and discharges of these chemicals may appear rather small in one
year, the loading in the environment builds up over time. While pollutant compounds deposited
from the air directly into a waterbody can have different routes of exposure to aquatic biota than
the same pollutants brought in by water or in sediments, there are limited quantitative data on
such differences in exposure. There is no current evidence that effects on wildlife, and
potentially on human health, caused by specific pollutants deposited from the air are different
from effects of those same chemicals carried in the water or sediment, once the chemical reaches
an organism's tissues.
Exposure of wildlife or humans to the pollutants of concern can occur directly (e.g.,
through intake of drinking water, direct contact with water) or as a result of food web
contamination. An indicator of potential human exposure to a pollutant is the presence of fish
consumption advisories issued by state agencies. These waterbody-specific and fish species-
specific advisories caution people against eating fish from a contaminated waterbody and
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CONCLUSIONS
suggest that consumption of fish with these levels of contamination may result in potential
human health effects. According to EPA's 1995 national listing of fish and wildlife consumption
advisories, current state advisories for the Great Waters are associated with the same pollutants
of concern as in the First Report to Congress (see Appendix B). Fish consumption advisories in
the lakes are most commonly issued for PCBs, followed by mercury and dioxins; in coastal
waters, advisories are commonly issued for PCBs, followed by dioxins.
Periodic monitoring of pollutant levels in tissues of aquatic organisms, such as game fish,
is another indicator of pollutant contamination and exposure and provides information on
bioaccumulation in the food web. Most studies are based on measurements of pollutant
concentration in fish from the Great Lakes. Studies of several pollutants show that, over many
years, pollutant levels in fish are remaining constant or decreasing. In some instances, slight
increases of some pollutants have been measured recently in certain fish species. For example,
although significant declines in PCB and DDT concentrations in lake trout, walleye, and coho
salmon in the Great Lakes were observed during the 1980s, more recently (i.e., in the last eight to
ten years) the residues of PCBs and DDT in these fish have leveled off or even increased slightly.
Chemical residues in fish tissue are probably the result of many factors in addition to deposition
from the air. For example, the apparent increase in pollutants in fish tissue may be a result of
resuspension of pollutants from sediment or from changes in the food web structure in the lake.
Adverse effects in wildlife and aquatic organisms in the Great Waters continue to be
reported in the scientific literature. The correlations of tissue burdens of persistent pollutants
with observed effects in the animals suggest that exposure levels for some pollutants continue to
be high enough to produce adverse effects. Health problems persist for fish and other wildlife in
certain Great Lakes locations, particularly for predators high in the food web, such as lake trout,
mink, and bald eagles. Recent population studies of fish-eating birds in the Great Lakes (e.g.,
common terns) provide evidence of the developmental problems linked to PCBs during the
1980s.
The occurrence of health effects in humans is less studied in connection with general
environmental exposures. Most information is based on laboratory studies in animals, which can
provide useful insight on potential adverse effects in humans; however, for most chemicals, the
lowest exposure concentration at which these effects would occur in humans is difficult to
determine. The pollutants of concern have been investigated individually and are known to
cause a variety of health effects, including cancer, and to act on many target organs, including
the liver and kidney, and on the endocrine, reproductive, immune, and nervous systems. There
are few recent studies of acute human exposures to Great Waters pollutants, although
evaluations of people who frequently eat fish from the Great Lakes suggest concerns. The
relative role of pollutants deposited from the atmosphere compared with other pathways
contributing to exposure has not been quantified in these studies.
Although much information is available on potential exposure to the pollutants of
concern and also on the potential effects of these pollutants, uncertainties still exist regarding the
association between the actual exposure levels experienced over time and potential effects.
Effects that occur in wildlife or humans from long-term exposure to pollutants of concern may
differ from those effects caused by acute, high-level exposures because longer exposure to some
chemicals can result in metabolism or breakdown of the chemical in the body to another
chemical that is more or less toxic and can result in cumulative exposure due to bioaccumulation.
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CONCLUSIONS
Comparison of the effects reported in laboratory studies to actual observations in the field (i.e.,
wildlife around the waterbodies) also needs to be addressed. Laboratory studies can provide
evidence to support observations of effects in the field and, furthermore, give information on the
possible mechanism of action of the effect. However, these studies generally do not duplicate
the potential cumulative or combined effects that may occur when pollutants interact in the
environment or simulate effects due to exposure in natural food chains.
Atmospheric deposition of nitrogen compounds can contribute significantly to
eutrophication in coastal waters where plant productivity is usually limited by nitrogen
availability. Eutrophication and its subsequent effects on estuarine ecosystems pose significant
problems for Chesapeake Bay and many other coastal waters. Accelerated eutrophication
frequently results in severe ecological effects such as nuisance algal blooms and reduced oxygen
levels in the water (as unstable algal blooms die back or organisms sink into deeper water). The
reduction in oxygen levels may result in altered food webs by reducing or eliminating bottom-
feeder populations of fish or shellfish, creating conditions that favor different species, or causing
dramatic fish kills. In some cases, overproduction of algae increases the suspended matter in the
water, which decreases light penetration to submerged aquatic vegetation (SAV) or coral. In
other cases, algae can overgrow directly on submerged living organisms, often with losses of SAV
or coral communities. Major areas of uncertainty include the response of living resources,
particularly SAV, to reductions in nitrogen loads and the tidal-flow exchanges between coastal
estuaries and offshore waters, which also receive atmospheric deposition of nitrogen
compounds. Further study is needed on the direct link between atmospheric deposition of
nitrogen compounds and ecosystem responses. Oxides of nitrogen are important components in
acidic deposition, wet and dry, to fresh waters. In addition, nitrogen compounds and their
reaction products in the ambient air can produce direct impacts on human health and terrestrial
vegetation. In consideration of these partial impacts, EPA has established programs to evaluate
and reduce the threat to human and ecological health from atmospheric nitrogen oxides, ozone,
particulates, and acidic aerosols.
Emission Sources that Contribute to Atmospheric Deposition in the Great
Waters
For toxic contaminants, information linking specific emission sources to impacts on
atmospheric deposition to the Great Waters has been limited. Some work has been done on
identification and characterization of specific sources in the Great Lakes, and more is planned.
Some of this work does not involve emission inventories, but consists of predicting the origin of
an air mass (using meteorology) that passes over a monitoring station and determining emission
sources based on observed pollutants and metals ratios in the air samples. For some source
categories, there currently are inadequate reliable emissions data and detailed emissions
inventories to link pollutant deposition to specific sources. However, for many source categories,
substantial progress has been made in recent years to establish source emissions inventories
through state and federal efforts. For example, the Great Lakes Emissions Inventory, recently
implemented by the eight Great Lakes states and the Canadian Province of Ontario, is compiling
a data base on emission sources of 49 toxic air pollutants that will provide information on local
and regional sources of pollutants of concern. A pilot project of major urban areas along the
southwest shore of Lake Michigan has created an inventory of small point and area source
categories in the surrounding region that contribute the most to the total emissions of major
pollutants. As a result of this pilot study, a better methodology has been developed for use in the
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CONCLUSIONS
full regional Great Lakes Emissions Inventory. Research studies on the importance of local
"urban plumes" of pollutants have been underway in recent years near Chicago (impacting Lake
Michigan) and near Baltimore (impacting Chesapeake Bay). These studies are due to be
completed in the next few years. Their results, combined with emission inventories, will assist in
defining the relative importance of local emissions upon deposition and in focusing emission
reduction efforts. In addition, EPA recently completed a national emissions inventory of known
U.S. sources of seven HAPs listed under CAA section 112(c)(6). Identification of the sources for
total emissions of these pollutants is necessary to assure that at least 90 percent of emissions from
stationary, anthropogenic sources are subject to regulation under CAA section 112(d).
As a result of research funded by the
Great Waters program and others, better
predictions can be made on the direction and
Under this section, EPA is required to identify
movement of emitted air pollutants over large
geographic areas, and more reliable estimates
of rates at which pollutants will be deposited
on land or water surfaces are possible. For
example, some researchers are determining ^o/^wo\
r ° subject to standards under section 112(d)(2) or
What is CAA Section 112(c)(6)?
and list sources, categories, and subcategories of
alkylated lead compounds, hexachlorobenzene,
mercury, PCBs, POM, TCDD, and TCDF. This list
is intended to assure that not less than 90 percent
of the aggregate emissions of each pollutant are
112(d)(4). To meet these requirements, national
inventories of sources and emissions of these
pollutants have been developed. Because all
seven pollutants are of particular interest to the
Great Waters program, these inventories will be
useful in protecting the Great Waters and in
implementing section 112(m).
the extent of mercury emissions to air in the
United States over an entire year, the
deposition to the land and waterbodies, and
the contribution by source category to the
total amount of mercury emitted and
deposited within the United States. In the
Great Lakes, a regional network of ten
monitoring sites was established in 1993 by
EPA and the University of Michigan to measure atmospheric mercury and wet and dry
deposition of gases and particulates. One goal is to determine the sources and source areas of
mercury deposition to the Basin, using an improved trajectory clustering technique. Such
studies will enable EPA and other researchers to better explore source attribution.
Substantial progress also has been made on investigating emission sources of nitrogen
compounds in recent years. Due to the impacts that nitrogen overenrichment has in estuaries
and coastal waters, sources of airborne and waterborne nitrogen compounds are being evaluated
by monitoring and modeling studies. Recent modeling studies have looked at both local and
distant sources (generic types) that release atmospheric nitrogen that deposits into the
Chesapeake Bay and its watershed. Using RADM, the Chesapeake Bay Program has evaluated
sources contributing to the deposition of certain nitrogen compounds and identified electric
utilities and mobile sources as major contributors. However, the model runs show that the
patterns of nitrate deposition are different for these two broad source categories. Utilities appear
to contribute a majority of the nitrate that deposits on the western side of the Bay watershed and
exhibit a decreasing trend in deposition from the western towards the eastern portion of the
watershed. Mobile source emissions, on the other hand, largely reflect the traffic associated with
the Washington, D.C./Boston corridor and contribute the majority of the nitrate that deposits
along the Delmarva Peninsula, the Bay itself, and lower portions of the western shore tidal
tributaries. Work on addressing a modeling uncertainty in RADM — correct partitioning
between particulate nitrate and nitric acid — continues with funding from EPA's High
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CONCLUSIONS
Performance Computing and Communications Program, the Particulate Program, and the Acid
Rain Program.
Contribution of Atmospheric Pollutant Loading to Exceedances of Water
Quality Standards and Drinking Water Standards or Exceedances of
Objectives of the Great Lakes Water Quality Agreement
While some pollutants remain at levels exceeding applicable criteria in some locations of
the Great Waters, no additional pollutants have been found to exceed water quality standards in
the Great Waters since the First Report to Congress. Where exceedances occur, it may be
reasonable to assume that atmospheric deposition contributes to some (quantity unknown)
extent. The contribution of atmospheric deposition is especially likely for open water
exceedances, in contrast to localized "hot spots" where other loading mechanisms may dominate.
Where data are available, toxic contamination in water does not appear to be increasing
significantly for any of the pollutants of concern, but rather appears to be remaining the same or
decreasing. However, recent data on water column concentrations are available for only a
limited number of the pollutants. Concentrations of DDT/DDE, dieldrin, hexachlorobenzene,
and PCBs in the water column of the Great Lakes are reported in both this report and the First
Report to Congress. Current levels of dieldrin and PCBs are lower than those presented in the
First Report to Congress; however, they continue to exceed the most stringent water quality
criteria for the Great Lakes by a substantial margin (tens to hundreds of times). These most
stringent criteria incorporate biomagnification up the food chain, and so differ from criteria for
direct exposure to water. In addition, the reported concentrations of DDT/DDE may exceed the
current water quality criteria under the Great Lakes Initiative; however, the possible exceedance
is difficult to establish given analysis limitations. Thus, even though mass emissions of these
pollutants have decreased dramatically as a result of actions taken to ban or restrict the
manufacture and use of these substances, the long-term persistence of these pollutants in the
environment, and apparent cycling among media, cause these compounds to remain pollutants
of concern to the Great Lakes. Therefore, these pollutants warrant continued monitoring and
tracking until levels no longer exceed relevant criteria or standards.
Among the Great Waters, the only significant sources of drinking water are the Great
Lakes and Lake Champlain. The drinking water systems using these sources are not known to
have exceedances of drinking water standards for the pollutants of concern, including toxics and
nitrates.
Description of Revisions to Requirements, Standards, or Limitations
Pursuant to the Clean Air Act and Other Applicable Federal Laws, as
Necessary
Section 112(m)(5)(E) requires that EPA describe in this report any revisions to the
requirements, standards, and limitations pursuant to the Clean Air Act and other applicable
federal laws that are necessary to assure protection of human health and the environment. In
reviewing relevant requirements, standards, and limitations established pursuant to applicable
statutes, EPA has found that such restrictions are achieving significant reductions in releases of
the pollutants of concern. For example, the technology-based standards that have been, and are
being, developed and promulgated for stationary air sources require reductions in air emissions
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CONCLUSIONS
that reflect the maximum that are achievable, in accordance with section 112(d). Section 112(c)(6)
specifically lists for special attention seven pollutants: alkylated lead compounds, poly cyclic
organic matter (POM), hexachlorobenzene, mercury, PCBs, furans (2,3,7,8 TCDF), and dioxins
(2,3,7,8 TCDD). These seven pollutants are also Great Waters pollutants of concern. A
comprehensive emission inventory has been developed under section 112(c)(6), and further
standards are being developed under section 112(d).
As mentioned earlier, section 112 authority is specific to HAPs listed under section 112(b)
and, therefore, does not apply to pollutants that are not currently listed, such as nitrogen
compounds. However, several major programs have been implemented under other sections of
the Clean Air Act to reduce emissions of oxides of nitrogen: sections 108 and 109, pertaining to
ambient air standards for stationary sources to protect public health and welfare; section 202,
pertaining to air regulations for mobile sources; and section 407, pertaining to acid deposition
control.
Nitrogen dioxide is listed under section 108 as a pollutant that causes or contributes to air
pollution that may reasonably be anticipated to endanger public health or welfare. Air quality
criteria have been issued by EPA for nitrogen dioxide, and ambient air quality standards have
been established for nitrogen dioxide under section 109, which directs the EPA Administrator to
propose and promulgate primary and secondary National Ambient Air Quality Standards
(NAAQS) for pollutants identified under section 108. A primary standard is one that is necessary
to protect the public health, allowing an adequate margin of safety. A secondary standard, as
defined in section 109, must specify a level of air quality needed to protect the public welfare
from any known or anticipated adverse effects associated with the presence of the pollutant in
the ambient air. Welfare effects, defined in section 302(h), include, but are not limited to, effects
on soils, water, crops, vegetation, materials, animals, wildlife, weather, visibility, and climate.
Thus, section 109 provides authority to address a broad range of public health impacts and
adverse environmental effects in order to assure protection of human health and the
environment.
Several efforts are currently underway to control emissions of nitrogen oxides. The
Ozone Transport Assessment Group, a regional body representing 38 eastern and midwestern
states, is currently evaluating alternative reduction options for regional control of nitrogen
oxides and volatile organic compounds in order to achieve attainment of the current NAAQS for
ozone. In addition, EPA is considering revisions to the NAAQS to address the most recent
information about health and environmental effects of ozone and fine particulate matter. A
subcommittee of the Clean Air Act Advisory Committee chartered under the Federal Advisory
Committee Act is evaluating regional approaches to the management of emissions of nitrogen
oxides, sulfur dioxide, fine particulate matter, and volatile organic compounds to attain the
proposed revisions to the ozone and particulate matter NAAQS and the national goals of the
regional haze program. Together these efforts are expected to result in substantial reductions in
emissions of the pollutants of concern, with significant additional benefits to geographic areas
such as the Chesapeake Bay watershed.
Furthermore, section 202 requires that standards for motor vehicles be established, as
needed, to reduce emissions that cause or contribute to air pollution that may reasonably be
anticipated to endanger public health or welfare. Regulations under this section apply to
emissions of nitrogen oxides. Section 401 (Acid Deposition Control) identifies the presence of
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acidic compounds and their precursors in the atmosphere, and in deposition from the
atmosphere, as a threat to natural resources, ecosystems, materials, visibility, and public health.
The principal sources of acidic compounds and their precursors in the atmosphere, as identified
in section 407, include nitrogen oxides from the combustion of fossil fuels. A program for
reducing emissions of nitrogen oxides from coal-fired electric utility power plants has been
promulgated under section 407 of the Clean Air Act. In the Acid Rain Phase II NO x Emission
Reduction Rule (Federal Register, December 19,1996), water quality benefits are cited in the
preamble justification as a basis for EPA's decision to exercise statutory discretion to lower
emission limits for certain coal-fired utility boilers (known as Group 1) and as an environmental
impact of establishing emission limits for other boiler types (known as Group 2). Eutrophication
is listed with ozone and acid deposition in the summary table of environmental effects.
Pesticides that are included as pollutants of concern have been, and continue to be,
effectively addressed by actions taken under relevant statutes. Also, PCB releases have been, and
are being, effectively reduced. While concentrations of some of these pollutants of concern in
the waterbodies or in animal tissue remain unacceptably high, current releases of these
pollutants are being effectively managed. It is important to note that, although current efforts
are effective and appropriate, some level of risk to the public health and to the environment may
continue for years into the future due to previous releases of the pollutants of concern and their
persistence in environmental media for multiple decades.
Various efforts are being taken by EPA that will provide significant concomitant benefits
through reduction of pollutants EPA addresses under section 112(m). At this time, no specific
revisions to requirements, standards, and limitations pursuant to the Clean Air Act or other
relevant federal statutes have been identified as necessary to assure protection of human health
and the environment in response to section 112(m) assessments. In the future, as EPA evaluates
progress of ongoing efforts and considers new information as it becomes available, new
approaches may be pursued.
V.B Future Directions
As described throughout the report, notable progress has been made to further the
knowledge of atmospheric deposition of pollutants to the Great Waters. As new information
becomes available on atmospheric pollutant deposition to the Great Waters, questions or issues
are expected to arise that will require further investigation or action. At this time, EPA has
identified areas where information is limited and has identified some specific directions that
need to be taken to advance the understanding of issues relevant to the Great Waters program.
Determine Management/Regulatory Actions for Focus Pollutants
EPA plans to continue evaluating the 15 pollutants of concern, focusing on those that are
currently being emitted to the air from sources subject to regulations under the CAA. For
example, emphasis will be placed on the seven pollutants of concern addressed in section
112(c)(6). Emission inventories have been developed for these pollutants and will provide useful
information on sources of atmospheric deposition to the Great Waters. EPA's Air Toxics program
has recently prepared some notable studies that may have implications to the Great Waters
pollutants of concern, including the Interim Report to Congress on emissions of hazardous air
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pollutants from electric utilities. The Interim Report, along with the Great Waters Second Report
to Congress and sponsored studies, contribute information focused on persistent pollutants to
EPA's ongoing actions establishing emission standards under section 112(d). As these standards
continue to become implemented, significant reductions in HAPs are expected, including the
persistent chemicals of importance to waterbodies. In addition to these activities, EPA is
considering future management and/or regulatory actions for some pollutants of concern, some
of which are described below.
Continue Monitoring and Research Efforts to Support
Management/Regulatory Actions
EPA plans to continue supporting monitoring and research efforts that provide
information for regulatory and management actions for pollutants of concern. Monitoring
allows tracking of current and future reductions and evaluation of EPA program effectiveness.
In addition, monitoring supports the development and validation of atmospheric transport
models that enhance EPA's program implementation and predictive capabilities. Research
projects include work that expands current monitoring capabilities, increases knowledge of
cycling and transport of contaminants, and evaluates environmental effects.
4 Exposure and Effects: A process to coordinate research strategies on persistent pollutants
has begun among several offices within EPA. It is expected that these studies will
improve our understanding of the relationship between ambient concentrations in
natural media (water, air, and sediments), burdens of pollutants in tissues of living biota,
and associated effects. Exposure and effects research will build on methods used to
develop the Great Lakes Water Quality Criteria, which incorporate consideration of
biomagnification. These types of research are central to increasing our ability to assess
the impact of atmospheric deposition to the Great Waters and define efficient approaches
to reducing exposures and risks to humans and wildlife.
4 Mercury and Compounds: Mercury is a global pollutant, and is used in industries and
released from combustion, manufacturing, and natural processes. Through changes in its
ionic and molecular chemistry, mercury can be mobile among the atmosphere, waters,
biota, and soil or sediments. EPA is committed to identifying feasible options for
reducing or preventing emissions of mercury. Also, following completion of EPA's
Mercury Study Report to Congress, the results will be used in the process of identifying
sources of mercury emissions and in prioritizing mercury reduction strategies. To date,
most routine monitoring for atmospheric mercury does not provide key information
needed to evaluate the sources and impacts of mercury loadings. This is due to the
relatively recent development of mercury techniques that differentiate between the
various molecular states of mercury and have not yet been widely and routinely used.
However, these techniques have been used on a research basis concurrent with
monitoring for other metals, in order to obtain an atmospheric "fingerprint" that aids in
the identification of sources. Monitoring for mercury is expected to continue in biota,
atmosphere, and other components of ecosystems, particularly in the Great Lakes region.
Monitoring should continue, to track future reductions of mercury, as emissions in the
United States are expected to decrease upon implementing recent CAA regulations such
as the municipal waste combustor rule, and the proposed standards for medical waste
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incinerators and for hazardous waste combustors. The effectiveness of voluntary
initiatives also should be evaluated.
Combustion Emissions: Combustion emissions (POM/PAHs, dioxins, furans, and PCBs)
are part of the EPA's toxics control efforts utilizing regulation, pollution prevention,
voluntary measures, and other approaches. Releases that affect the Great Waters include
past usage, combustion (including combustion of wastes), and cycling or movements
among the components of ecosystems. For example, although PCBs have not been
manufactured for a long time, they remain in use within existing electrical equipment.
When released into the environment, PCBs have proven to be one of the most persistent
of the pollutants of concern. Regulatory action to control these pollutants under the CAA
can be complex because current emissions of these toxics from any one source may be a
small percent of total loadings. However, their persistence and the tendency of many of
the chemical species to biomagnify gives them a particular importance. Research on
effects to wildlife associated with environmental exposures, including mixtures of toxics,
is expected to continue. Monitoring of fish-eating birds and other wildlife in the Great
Lakes should be performed with respect to their geographic relation with the Areas of
Concern (AOCs). The compounds grouped under POM, including PAHs, have had less
attention in monitoring in the past, but because they are still being emitted, special focus
on monitoring and studies of effects are expected. PAH trends are currently tracked in
the Great Lakes.
Pesticides: Persistent pesticides (chlordane, DDT/DDE, dieldrin, hexachlorobenzene,
cc-HCH, lindane, and toxaphene) are difficult to control through regulation under the
CAA since the most significant potential sources to the Great Waters may not be from
current emissions. Releases by several pathways to the Great Waters are due in many
cases to past use, often over considerable areas, while cycling or movements among Great
Waters' ecosystem components can release earlier contamination. In addition, current
human activities, including combustion, can still emit small quantities. Use of all the
pesticides of concern are either canceled or severely restricted in the United States, yet
they continue to be found in sediments of waterbodies. Research is expected to focus on
possible current sources as byproducts or long-range transport of toxaphene and dieldrin
due to their continued importance in some of the Great Lakes. These chemicals are
retained on the list of Great Waters pollutants of concern, and EPA believes that efforts at
preventing and controlling releases of these chemicals are warranted, including
continued monitoring until levels no longer warrant fish advisories or exceed water
quality criteria and standards.
Nitrogen Compounds: EPA is focusing on management strategies to reduce nitrogen
oxide (NO,,) emissions. EPA expects that total NOX emissions will gradually decline about
six percent from current levels by the year 2000 due to mandatory CAA programs. After
the year 2000, the total national NOX emissions are expected to gradually increase due to
population growth. EPA is developing the Integrated NOX Strategy, which outlines an
integrated approach to controls on mobile and stationary sources through cost-effective
mechanisms. The Strategy stresses that consideration of the many environmental effects
of NOX emissions should strongly influence policy decisions regarding the control of NOX
emissions. Accordingly, EPA continues to work in coordination with a wide range of
stakeholders to develop and implement new mobile and stationary source control
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programs at the federal, state, and local levels to reduce NOX emissions. Monitoring of
future reductions in conjunction with estuarine, watershed, and acid deposition studies is
expected to continue. Monitoring should continue to include a comprehensive approach
that addresses wet and dry deposition of gases and particulates. Additional research will
proceed on improving monitoring methods for dry particles and on quantifying the
relative contribution of the chemical species of nitrogen compounds to total loading.
Modeling will be important in addressing the multiple questions and benefits that
strategies for reducing NOX are developing in conjunction with programs on ozone and
fine particulate matter, as well as impacts on waterbodies.
Expand Modeling Efforts to Estimate Atmospheric Loadings to Great Waters
As data continue to be gathered from studies that were initiated in recent years, the
results will lead to better characterization of atmospheric loadings to the Great Waters. One
particular study that should provide comprehensive information is the Lake Michigan Mass
Balance Model. This model should be adapted and applied to additional waterbodies. EPA also
believes that more investigation is needed to assess the contribution of atmospheric deposition to
pollutant loadings from urban, stormwater, and agricultural runoff from the watershed. This
kind of work is currently being performed for nitrogen compounds in Chesapeake Bay. Results
from such projects will provide more comprehensive information to assess the complete picture
of atmospheric loadings to the Great Waters.
Increase Focus on Identification of Emission Sources
Significant progress has been made in establishing source emission inventories for some
pollutants of concern. However, information is limited on specific sources of atmospheric
deposition to the Great Waters, especially sources that are relatively distant from the waterbody.
Because this information is critical to developing risk management strategies, EPA believes that
more effort should be placed on determining potential sources of these airborne pollutants, with
emphasis on identifying significant sources, both local and long range. As described above,
source emission inventories have been initiated in the Great Lakes region and nationally, which
will be important in identifying source categories of concern. The Chesapeake Bay Program has
made important progress in identifying local and distant sources for nitrogen deposition to the
basin, but has not determined the specific sources that contribute the most to deposition.
Another future area of study for EPA is atmospheric pollutant deposition from sources
other than current air emissions. As discussed earlier, many of the pollutants of concern to the
Great Waters are no longer used or manufactured in the United States; however, they cycle in
the environment, may be transported considerable distances, and thus can contribute some
unknown amount to the waters. Investigations on the relative contribution of deposition from
current activities versus past use is an important concern to EPA because several of these
pollutants may need to be addressed through approaches that supplement prevention measures
and emission controls developed under the CAA.
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Continue to Promote Pollution Reduction in the Great Waters
In the past few years, local, regional, and federal agencies, as well as international
organizations, have worked together to develop initiatives and agreements that promote
activities supporting pollution prevention and reduction efforts in the Great Waters. As such,
several of these activities will help to address issues under CAA section 112. Many of these
programs, which are described in Chapter IV of this report, were developed recently, and
implementation of these initiatives is expected to occur in the near future. EPA is committed to
continue its support for, and involvement in, these activities. Some of these broad initiatives are
highlighted below:
4 Strategic pollution prevention plans developed through federal, state, and local partnerships.
Many waterbodies of the Great Waters currently have specific goals or strategies to
characterize and/or reduce water pollution in their respective ecosystems. Most plans
promote comprehensive approaches to reduce contamination in a waterbody. Where
atmospheric deposition is a significant contributor, EPA is committed to using its section
112 authorities to assist in achieving the emission reductions feasible. As appropriate,
other authorities may be considered as well (e.g., provisions of the CAA to reduce
emissions of nitrogen compounds).
4 Use of voluntary efforts to meet pollution reduction goals. Pollution reduction goals have
been developed for many Great Waters and, in most instances, implementation of these
goals involves voluntary initiatives. For example, state agencies and other stakeholders
in the Great Lakes region have worked together to propose voluntary, as well as
regulatory, measures to prevent or reduce atmospheric mercury contamination in the
Great Lakes through increased public awareness, development of alternative
technologies, and capturing and recycling of uncontrolled (fugitive) releases. Many
activities by industries, individuals, and cities that reduce waste of energy and develop
efficient transportation also have the benefit of reducing NOX emissions.
4 Binational and international efforts to promote pollution reduction. Binational efforts can
play a critical role in controlling atmospheric pollution in the Great Lakes. For example,
the Great Lakes Water Quality Agreement and the recently signed Binational Strategy for
Virtual Elimination between the United States and Canada have set percentage reduction
goals as steps towards virtual elimination of persistent, toxic, and bioaccumulative pollu-
tants from the Great Lakes. Through these endeavors, both nations are encouraging and
supporting voluntary programs and other actions to reduce generation, use, and release
of toxic contaminants to the Great Lakes. In addition, EPA works in cooperation with
other agencies and departments to develop and support additional binational and global
actions to address atmospheric sources of persistent organic and heavy metal emissions.
4 Implementation of the Great Lakes Water Quality Initiative. The primary purpose of the
Great Lakes Water Quality Guidance (GLWQG) is to provide a consistent level of
protection to people, aquatic life, and wildlife that may be exposed to toxic pollutants
from the Great Lakes. To accomplish this goal, the GLWQG establishes protective levels,
or water quality criteria, for toxic pollutants from all sources. Estimates of basin-wide
toxic reductions that will result from implementation of the Great Lakes Water Quality
Initiative range from 2.6 million to 3.5 million kilograms of toxic pollutants per year.
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4 Continue to take strategic actions. Some argue that any continuing releases of persistent
bioaccumulative pollutants add to an environmental burden that is already causing
effects. EPA believes it is important to balance its present understanding of atmospheric
deposition against the implications of inaction in order to define those actions that are
justified at this time. EPA is committed to protecting public health and the environment
and will promote taking whatever regulatory actions and voluntary initiatives are
appropriate in the most cost-effective way possible.
Assess Economic Impact of Pollution to the Great Waters
The economic impacts associated with reductions of pollutants to the Great Waters have
not been sufficiently investigated, although a regulatory impact analysis was recently performed
on the Great Lakes Water Quality Guidance, which addressed the impacts of the new guidance.
For the Great Waters program, EPA plans to identify and quantify, where possible, economic
impacts associated with exposure and effects indicators such as fish advisories, habitat decline,
diminished species diversity, fish kills, and declining populations of contaminated shellfish and
fish.
V.C Draft Determination of Whether CAA Section 112 Authorities are
Adequate to Prevent Adverse Effects to Public Health and the
Environment from Deposition of HAPs
In accordance with section 112(m)(6) of the CAA, EPA is issuing, at the same time it
submits this Report to Congress, a draft determination of the adequacy of the other legal
authorities and mandates provided by section 112 of the CAA to prevent specified adverse
human health and environmental effects associated with atmospheric deposition to the Great
Waters. Based on the information available in this report and in the draft determination
regarding the adequacy of section 112 authority, EPA is also issuing a draft determination of
whether additional emissions standards or control measures, beyond those authorized or
required by section 112, are needed to prevent such effects. These draft determinations are
described in a Federal Register notice published separately and are briefly summarized below.
Section 112(m)(6) of the CAA requires that EPA determine whether adequate authority
exists within the other (i.e., non-Great Waters) provisions of section 112 to prevent serious
adverse effects to public health and serious or widespread environmental effects resulting from
atmospheric deposition of HAPs to the Great Waters. In making this determination, EPA
reviewed the authority granted by the other provisions, as they may apply to deposition of HAPs
to the Great Waters. It should be emphasized that this determination pertains to the authority
within the CAA to take actions as appropriate to address adverse effects.
In addition, EPA has focused on the authority within section 112 to address those
pollutants and sources within the scope of section 112. Therefore, pollutants such as nitrogen
compounds that are not on the section 112(b) list of HAPs are not within the scope of this
determination. Similarly, sources that are regulated by other sections of the CAA (e.g., mobile
sources) or that are addressed by other statutes (e.g., wastewater discharges, which are addressed
by the Clean Water Act) are also not within the scope of this adequacy determination.
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Section 112 establishes a statutory scheme by which EPA is to identify HAPs that may
cause or contribute to adverse effects to public health or the environment, develop standards for
the control of emissions from stationary sources of such HAPs, and adjust these control
requirements as needed to address any remaining unacceptable risk that may be present after
imposition of sources have complied with the emission standards. The types of adverse
environmental effects to be prevented are defined in the Act and are broad in scope.
Authorities provided by other provisions of section 112 that may be particularly relevant
to the Great Waters pollutants and sources are briefly summarized below and, as stated earlier,
are described in more detail in the Federal Register notice. Section 112 authorizes EPA to:
• Identify and list additional air pollutants that may cause adverse effects due to
atmospheric deposition (section 112(b));
• Identify and list any stationary source category that emits pollutants with the
potential to cause adverse effects (section 112(c));
• Establish a lesser quantity (e.g., below ten tons per year for a single pollutant)
emission rate for defining major sources based on several factors, including
persistence and potential to bioaccumulate (section 112 (a)(l));
• Promulgate performance standards based on best performing technologies for
major sources and listed area sources (section 112(d)); and
• Require additional controls, beyond the section 112(d) standards, as necessary to
provide an ample margin of safety to protect public health or to prevent an
adverse environmental effect (section 112(f)).
Based on its analysis of these and other section 112 provisions, EPA has issued a draft
determination that section 112 authority is adequate to prevent serious adverse effects to public
health and serious or widespread environmental effects associated with the deposition of HAPs
to Great Waters. Consequently, EPA also has issued a draft determination that, at this time, no
further emissions standards or control measures beyond those authorized under the other
provisions of section 112 are necessary and appropriate for stationary sources of HAPs to prevent
such effects. EPA has requested public comment on these draft determinations, which will be
finalized in March 1998.
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APPENDIX A
STATUS OF ACTIONS RECOMMENDED
IN FIRST REPORT TO CONGRESS
This appendix provides information on the status of the actions that were recommended in
the First Report to Congress on atmospheric deposition to the Great Waters (see Table A-l) and lists
the emissions standards that may control the Great Waters pollutants of concern (see Table A-2).
A-l
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TABLE A-l
Status of Actions Recommended in First Report to Congress
Recommended Action
Status
1. EPA will continue ongoing efforts to implement section 112 and other sections of the Clean Air Act, as amended in 1990, and will use the
results of this report in taking reasonable actions to reduce emissions of Great Waters pollutants of concern.
a. EPA is developing standards under section 112(d) for
approximately 35 source categories of Great Waters hazardous air
pollutants (HAPs) of concern, consistent with the schedule
published in response to section 112(e)(3). Where possible, given
other factors, EPA will publish section 112(d) standards ahead of
schedule for specific source categories. Great Waters Program funds
will be used to develop and publish ahead of schedule section
112(d) standards for at least one source category.
Fiscal year 1994 Great Waters funds supplemented the development of
the primary aluminum maximum achievable control technology
(MACT) regulation. As a result, the standard was proposed on
September 26,1996. This regulation has been developed via a successful
partnership with industry, states, and environmental and tribal
interests. The standard primarily addresses fluoride emissions but will
also include limits for polycyclic organic matter (POM), the Great
Waters pollutant that made this source category a choice for Great
Waters funding. Promulgation of this standard is expected in late 1997.
b. During the process of developing emission standards, EPA will
evaluate whether the currently defined MACT floor for existing
sources represents a sufficient level of control for sources that emit
Great Waters pollutants of concern.
At present, the tools to quantitatively evaluate a "sufficient level of
control" for Great Waters pollutants do not exist. Nonetheless, in
support of this recommendation, Great Waters pollutants are being
considered as various source categories are evaluated for pollution
control. Table A-2 lists emission standards currently being developed,
or which have been completed, that address emissions of some of the
Great Waters pollutants of concern.
c. As soon as practicable, EPA will publish an advance notice of
proposed rulemaking (ANPR) to notify the public of EPA's interest
in establishing lesser-quantity emission rates or LQERs (i.e., less
than 10 tons per year) for selected Great Waters HAPs for the
purpose of defining sources emitting these HAPs as "major sources"
and to solicit comment. EPA will also evaluate whether any Great
Waters HAPs warrant establishment of an LQER, and, if
appropriate, based on that evaluation and the comments on the
ANPR, EPA will develop a notice that proposes LQERs for those
pollutants for which an LQER is warranted.
At this time, EPA has postponed development of LQERs. The primary
impact of developing an LQER for a pollutant or source category is the
consequent definition of that source as a "major" source and thus
subjecting that source to certain requirements under CAA section 112.
Most sources of the pollutants for which LQERs were being considered
are already defined as major, and thus the establishment of an LQER
would have little effect. For those sources that are area sources,
performing an "area source finding" is a more efficient way to assess
source categories as they come up for regulation rather than an up-front
LQER analysis with more generic data. Also, there is sufficient statutory
authority to require MACT on sources of any size regardless of their
definition as major or area sources. In the future, however, EPA may
decide that LQERs are warranted for specific source categories or
pollutants at which time this effort could be re-initiated.
A-2
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TABLE A-l
Status of Actions Recommended in First Report to Congress
Recommended Action
Status
d. During the process of standards development for major sources,
EPA will determine whether area sources of Great Waters HAPs
warrant regulation under section 112(d) and, if so, which area
sources. Results of the assessment will be integrated into the
strategy for area sources under development in accordance with
section 112(k).
EPA has evaluated 15 area source categories to determine whether
regulation of these sources is warranted under section 112(d). These
included four source categories emitting lead or dioxins. To date, none
of the source categories emitting these Great Waters pollutants has
warranted an "area source finding" based on a risk assessment. Area
source analyses will continue to be performed as appropriate.
e. For the urban area source strategy (section 112(k)), EPA will
evaluate public health effects on the basis of total exposure, which
would include exposure by inhalation as well as exposure through
ingestion of food containing bioaccumulated urban toxicants.
To assess total exposure to HAPs and criteria pollutants, EPA is
currently developing the Total Risk Integrated Model (TRIM). The
TRIM will be a probabilistic model capable of assessing risks to humans
and to populations in an ecosystem resulting from multimedia
contamination (in air, water, soil, and food) and multipathway exposure
(via inhalation, ingestion, and absorption exposure routes). The TRIM is
expected to be available for use by December 1999.
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f. EPA will conduct a pilot project examining the use of Great
Waters impacts analyses in the development of section 112(d)
standards.
EPA has recently developed a new modeling tool for the assessment of
atmospheric deposition of pollutants to the Great Waters. REMSAD, the
Regulatory Modeling System for Aerosols and Deposition, is a work
station-based Eulerian model intended for use in assessing the impacts
of regulatory activities, such as section 112(d) MACT standards, on
loadings of pollutants of concern to the Great Waters. REMSAD is
currently capable of simulating short-, medium- and long-range
transport and deposition of mercury, cadmium, dioxins, and POM;
other pollutants, including other toxics as well as nitrogen, may be
incorporated in future work. Initial model demonstration and
evaluation will be completed during 1997. The model is currently
available on the OAQPS Support Center for Regulatory Air Models
(SCRAM) bulletin board.
As part of the REMSAD development and demonstration activities, EPA
will conduct a pilot study that will examine the impacts of the Emissions
Guidelines for Municipal Waste Combustors (MWCs) on deposition of
pollutants of concern to the Great Waters. Like section 112(d) standards,
the MWC standard is based on MACT. The MWC category was chosen
because it satisfied several requirements for an effective pilot study: (1)
it includes a large number of sources; (2) it emits significant quantities of
several pollutants of concern, including dioxins, furans, cadmium,
mercury, and POM; (3) and suitable emissions data are available. The
pilot study will estimate changes in annual loadings of these pollutants
to the Great Waters due to implementation of the MWC standard.
g. For Great Waters HAPs, EPA is proposing a cap (i.e., 0.01 ton per
year) to the de minimis levels being developed under section 112(g),
so that controls would be required for more sources of Great Waters
HAPs as they modify their processes. EPA will determine the
appropriate de minimis level on a chemical-by-
chemical basis, giving consideration to the chemical's persistence,
propensity to bioaccumulate, and such other factors that EPA
considers relevant.
In the proposed section 112(g) rulemaking, de minimis emission rates
were proposed for HAPs identified as being of concern for Great Waters
(based on toxicity, bioaccumulation, and bioconcentration). However,
the H2(g) rulemaking that was promulgated did not include the
provisions pertaining to modifications and, thus, the de minimis levels
were not needed and were not included in the final rule.
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h. EPA plans to propose a revised MWC rule, with stringent
controls on mercury emissions and emissions of other Great Waters
HAPs, not later than summer 1994.
On September 20,1994, EPA proposed New Source Performance
Standards (NSPS) and Emission Guidelines (EG) applicable to MWC
plants larger than 35 megagram (Mg) per day capacity. These
regulations were finalized on October 31,1995. For mercury, the final
standard for new and existing MWCs is 0.08 milligram (mg) per dry
standard cubic meter (dscm), or about 90 percent control. The final rules
also apply to dioxins. The air pollution control system used to comply
with the CAA section 129 guidelines achieves greater than 95 percent
dioxin reduction.
i. EPA is conducting studies that will provide information for future
Great Waters reports. The mercury study, under section
112(n)(l)(B), will evaluate the rate and mass of mercury emissions
from all sources, the health and environmental effects of such
emissions, technologies to control such emissions, and the costs of
these control technologies. The utility study, under section
112(n)(l)(A), will evaluate the hazards to public health reasonably
anticipated to occur as a result of emissions of all HAPs by electric
utility steam-generating units. Findings of these studies will be
relied upon in future Great Waters reports in the development of
strategies for reducing environmental exposures to Great Waters
pollutants.
EPA has prepared a draft seven volume Report to Congress on mercury
which was submitted to EPA's Science Advisory Board for peer review
in June 1996. The report was favorably reviewed in February 1997 and
EPA expects to finalize and submit the Report to Congress in fiscal year
1998.
In October 1996, EPA submitted to Congress an interim report on utility
air toxics (U.S. EPA 1996e). Entitled Study of Hazardous Air Pollutant
Emissions for Electric Utility Steam Generating Units — Interim Final Report
(EPA-453/R-96-103abc), this document addresses inhalation and non-
inhalation exposures to utility emissions. A final report, including a
regulatory determination for utility control under section 112 is due
January 15,1998. The Executive Summary of the interim Utility Study
can be accessed through EPA's Technology Transfer Network (TTN) by
calling (via modem) 919-541-5742.
j. EPA is developing ecological effects assessment screening
methods for reviewing petitions to add and delete pollutants from
the HAP list and to delete source categories from the source
category list. EPA will consider the Bioaccumulation Factor
Methodology (58 Federal Register 20802) in the development of these
ecological effects assessment methods. The purpose is to help
ensure that ecological effects, in addition to health effects, will be
considered in determining whether regulation is warranted.
This activity is ongoing. Under section 112(f), EPA is to consider the risk
to public health remaining, or likely to remain, after sources are
regulated under the section 112(d) MACT program. These additional
standards, so-called "residual risk standards," will consider
environmental as well as public health impacts. Under this effort,
ecological effects assessment and screening methods are being
developed.
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Status
k. EPA will evaluate whether other pollutants, including
hexachlorobutadiene and methoxychlor, which are proposed
Bioaccumulative Chemicals of Concern under the proposed Water
Quality Guidance for the Great Lakes System (58 Federal Register
20802) and which have been identified as having potentially
significant air sources, should be added to the list of Great Waters
pollutants of concern.
This activity is ongoing. In addition to hexachlorobutadiene and
methoxychlor, atrazine is also under consideration for addition to the
list of Great Waters pollutants of concern.
1. EPA is continuing to emphasize pollution prevention as the goal
in the development of control measures to reduce emissions of
Great Waters pollutants of concern and is encouraging any
voluntary pollution prevention and other emission reduction
efforts.
There are a number of ongoing EPA activities that emphasize pollution
prevention as a goal in the development of control measures. These
activities are described in detail in Chapter IV of this report and include
such projects as the Virtual Elimination Pilot Project, the Great Lakes
Binational Toxics Strategy, development of Lakewide Management
Plans (LAMPs), and the Great Lakes Water Quality Guidance.
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m. In the development of regulations and pollution prevention or
reduction strategies under the 1990 CAA Amendments, EPA will
examine the potential for reductions of oxides of nitrogen and will
determine how additional nitrogen oxide (NOJ reductions can be
achieved for protection of coastal water quality and related
resources.
EPA's Integrated NOX Strategy is described in the staff working draft
document entitled "Nitrogen Oxides Impacts on Public Health and the
Environment" (U.S. EPA 1997). This strategy will coordinate control
efforts to maximize environmental benefits of reductions in ozone
precursors, fine particulates, acidic deposition and eutrophication. The
document was distributed to the CAA Advisory Committee at their
December 5,1996 meeting and public comments were requested by
January 31,1997. The document was also described at an Ozone
Transport Assessment Group (OTAG) meeting and placed on OTAG's
TTN web site.
Several National Estuary Program sites are investigating the role of
atmospheric deposition of nitrogen compounds in eutrophication.
Another EPA activity called the Clean Air Power Initiative (CAPI)
produced an October 1996 report that summarizes a strategy to cost-
effectively reduce emissions of NO,,, SO^ and mercury from utility
boilers. CAPI information is available on the web site:
www.epa.gov/capi.
EPA has also proposed new ozone and particulate matters standards
(December 13,1996). EPA plans to complete the final rulemaking by
July 19,1997. These rules are expected to significantly reduce NOX
emissions, as will the revised NOX New Source Performance Standard
(NSPS) for utility and non-utility units. EPA is required to propose the
NSPS by July 1,1997.
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Status
n. EPA will develop Alternative Control Technology documents
(ACTs) for NOX. This is expected to result in nationwide NOX
emissions reductions, thus protecting coastal waters, as states
develop regulations under the National Ambient Air Quality
Standards program (NAAQS).
The ACT documents were required under section 183 of the CAA.
These documents describe a wide range of NOX control technologies for
nine specific source categories (cement manufacturing, gas turbines,
glass manufacturing, internal combustion engines, iron and steel,
nitric/adipic acids, non-utility boilers, process heaters, and utility
boilers). Great Waters funds were used to develop two of these
documents. The purpose of the ACT documents is to help states adopt
rules to meet the NOX Reasonable Available Control Technology (RACT)
requirements by May 31,1995. In addition, the ACT documents should
help states that develop beyond-RACT rules related to ozone attainment
plans. Copies of the ACT documents are available from the National
Technical Information Service at 1-800-553-NTIS.
2. EPA recognizes the need for an integrated multimedia approach to the problem of atmospheric deposition of pollutants to waterbodies
and, therefore, will consider authorities beyond the Clean Air Act to reduce human and environmental exposure to Great Waters pollutants
of concern.
a. EPA will establish a funding and operational mechanism for all
appropriate offices to pool their resources (both dollars and
personnel) to more effectively and efficiently manage this
multimedia problem. The Great Waters Core Project Management
Group will serve as the liaison among EPA's Assistant
Administrators (AAs) and Regional Administrators (RAs). Through
this group, commitments will be obtained from each of the AAs and
RAs to earmark funds for implementing the recommendations of
the First Report to Congress or to take a lead role in the
implementation of specific recommendations.
Evaluation of the opportunities for pooling resources between EPA
offices showed that there was no available funding mechanism to do so,
and that it would be impractical to develop such a mechanism. The
Core Advisory Work Group agreed instead that the participating
offices/agencies would integrate Core Group input into the planning for
Great Waters-related efforts within their offices/agencies, as well as
providing their input in planning Great Waters-funded activities. This
integration of activities is ongoing.
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Status
b. EPA should use the discretionary authority in existing statutes to
regulate or prohibit multimedia environmental releases that cause
or contribute to a water quality impairment. The Administration
wants to work with Congress (e.g., on Clean Water Act
reauthorization) to develop approaches that would allow effective
pollution control where other federal environmental statutes are not
effective and where an integrated multimedia approach is the most
efficient means to reduce unacceptable risk. This would not apply
to mobile sources or pesticide programs. EPA would use the most
appropriate existing environmental statute (e.g., the Clean Air Act
for air releases) for controlling the release and would take into
account the factors of revised section 307(a)(2) of the Clean Water
Act.
In 1997, efforts to reauthorize the Clean Water Act are still ongoing.
c. Congress, with technical support from EPA, should develop
legislation to prohibit the exportation of any pesticide product
which contains an active ingredient that has been banned for all or
virtually all uses in the United States. The recommendation to
prohibit the export of banned pesticides was presented in the Report
of the National Performance Review: Creating a Government That Works
Better and Costs Less.
Such legislation was introduced into a Congressional committee in 1995,
and failed to pass.
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Status of Actions Recommended in First Report to Congress
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d. EPA will work with other countries to explore possible
alternatives to reduce or eliminate the production, export, and use
of pesticides banned in the United States.
This activity is ongoing. EPA currently participates in the North
American Commission for Environmental Cooperation, which was set
up as a parallel agreement to the North America Free Trade Agreement.
In that group, EPA is a member of the Working Group on the Sound
Management of Chemicals, which has established task forces on
mercury, PCBs, DDT, and chlordane. EPA also represents the United
States in negotiations on the Long-Range Transport of Air Pollution
(LRTAP), which includes a number of these substances. In the near
future, EPA will be representing the program on the United Nations
Environmental Program negotiations on Persistent Organic Pollutants,
the list for which is now under consideration, but which will likely
include the LRTAP substances, as well as some others.
EPA is currently participating in the negotiations for another United
Nations treaty on Prior Informed Consent, which will control the
international trade of many "delisted" (i.e., banned) substances.
e. EPA will explore the feasibility of creating an inventory of
pesticide use within the United States and of establishing a program
to identify and quantify stockpiles and emissions of pesticides of
known and potential concern, including banned pesticides.
EPA believes that creating such an inventory is possible from annual
information submitted under section 7 of the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA, as amended by the Food
Quality Protection Act of 1996). This information would cover basic
producer and formulator inventory changes. Additional proprietary
data sources could cover farm level inventories. While this type of
inventory is feasible, EPA currently has no plans to compile this
information.
f. EPA will continue to emphasize pollution prevention as a goal
and to encourage voluntary pollution prevention efforts that lead to
reductions in releases of Great Waters pollutants of concern.
Several pollution prevention projects that address Great Waters
pollutants of concern are currently underway:
The highlights of many of these efforts and milestones reached,
including the PCB phaseout program and clean sweep actions, can be
found in the document Toward a Brighter Future, EPA Region 5, the First
25 Years, 1970-1995, EPA-905-F-96-001,1996.
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A "Virtual Elimination Pilot Project" is underway in the Great
Lakes Basin, as part of a comprehensive toxics reduction effort.
The Virtual Elimination (VE) Pilot Project proposes selecting a
small group of toxics as a pilot and performing an in-depth
analysis of opportunities for reduction from all sources.
The "pilot" portion of the VE project focused on the reduction of
mercury and PCBs. A stakeholder meeting was held in the Great Lakes
region in 1993. Based on the meeting, a draft report was developed by
EPA to identify options to reduce mercury. A similar paper is currently
being prepared by EPA to address PCBs. This project will continue with
additional analyses of classes of substances rather than the use of a
chemical-by-chemical approach.
- EPA has initiated a project to reduce risks from PCBs by asking
all utilities in the Great Lakes area to voluntarily decommission
their PCB electrical equipment.
- The Lake Superior Pollution Prevention Strategy was released in
October 1993 as part of the Lake Superior Binational Program.
Twelve major utilities in the Great Lakes basin conducted a study of the
utility industry in EPA Region 5 and reported that the utilities have
collectively removed almost 90 percent of the PCBs they had in service
as of 1978. Individually, most of the 12 utilities indicated that they
would continue efforts to remove PCB electrical equipment and several
other utilities offered to assist with PCB phaseout outreach.
In December 1995, Northern Indiana Public Service Company (NIPSCO)
became the first utility to officially and formally commit to phase down
its remaining PCB electrical equipment as part of the PCB Phasedown
Program. Their commitment will involve the replacement or removal of
all of their PCB equipment or PCB-contaminated oil in the equipment
over the next 10 years with the vast majority of the PCBs being phased
down within the next five years.
As discussions on company-specific PCB reductions continue, EPA
concurrently drafted a policy that could offer certain enforcement
related credits to facilities that meet specific PCB phaseout targets. Once
the policy is finalized, EPA expects renewed interest and participation in
the PCB Phasedown Program.
This effort has been completed.
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- EPA, together with state Departments of Agriculture and local
government agencies, has funded a series of "Clean Sweeps" to
collect and properly dispose of existing stocks of canceled
pesticides from residents in the Great Lakes area.
In the Lake Michigan basin, agricultural "clean sweeps" to properly
collect and dispose of unused pesticides have been conducted in
Indiana, Michigan, and Wisconsin. Also, a variety of pollution
prevention and technical assistance projects have taken place in
Milwaukee, Chicago, and western Michigan. EPA continues to fund
agricultural clean sweeps on a modest but consistent level, encouraging
states to develop innovative approaches to pesticide collections.
Michigan, Minnesota, and Wisconsin are setting up permanent
collection sites (similar to household hazardous waste sites) where
pesticides will be collected over a number of years.
g. EPA will continue its work with Canada, under the Great Lakes
Water Quality Agreement, on airborne toxic substances. These
continuing bilateral efforts are assisting and will continue to assist in
meeting Great Water program objectives during the 1990s.
EPA is continuing its work with Canada, as parties of the Great Lakes
Water Quality Agreement, and with the activities of the International
Joint Commission, as well as having Canadian input on major Great
Waters planning and reporting activities. In April 1997, the United
States and Canada also agreed to a strategic plan for eliminating toxic
substances from the Great Lakes by 2006. The Great Lakes Binational
Toxics Strategy calls for a number of milestones to be achieved from
1997 to 2006 including reductions in mercury, PCBs, and dioxins. The
two countries have also agreed to boost bilateral cooperation to address
pollution that crosses boundaries and to cooperate on environmental
research and technology. A memorandum of understanding is to be
signed in September 1997.
h. EPA will distribute technical information to state and local air
and water agencies to facilitate cooperative efforts toward common
goals to further reduce human and environmental exposure to
Great Waters HAPs.
Outreach to state and local air and water agencies is an ongoing process.
These efforts are exemplified by such programs as the Great Lakes
Information Network, the Technology Transfer Network (TTN), the
Regional Air Pollution Inventory Data System (RAPIDS), and other
electronic information sources such as a number of EPA home pages on
the World Wide Web. In addition, EPA continues to develop emission
factors for state and local use in developing emission inventories. These
documents are available electronically on the TTN.
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Recommended Action
Status
i. EPA will initiate discussions about possible mechanisms that
regional EPA offices and state agencies could use for sharing
information on new or renewal permit applications for sources with
the potential to emit Great Waters pollutants of concern.
This activity has yet to be initiated. If, in the course of new permit
applications and renewals, there appear to be common issues among the
states with respect to Great Waters pollutants, the regional EPA offices
may initiate some mechanism to provide information exchange and
consistency between the various permitting agencies. To date, with the
early implementation of the permitting programs, this has not been an
issue.
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Status
3. EPA will continue to support research activities and will develop and implement a strategy describing necessary research and policy
assessments to address the mandates of section 112(m).
a. EPA is developing a strategy to target research necessary to
answer the scientific questions outlined in section 112(m). The
strategy will be reviewed by EPA's Science Advisory Board and will
influence decisionmaking on the priority and funding for future
research. This strategy will focus on utilization of the mass balance
approach for determining relative loading and will acknowledge the
need for a balance between monitoring, modeling, and emission
inventory efforts for that work. The strategy will also consider how
to better identify those persistent chemicals with the tendency to
bioaccumulate that may become problematic if emissions continue.
Included in the strategy will be an assessment of the need for
development of tools that can be used to: (1) assess and quantify
the human health and environmental risk from exposure to air
toxics, especially via indirect exposure routes, and (2) quantify the
social, environmental, and economic benefits and costs of pollution
prevention and regulatory actions.
EPA is working on a research strategy for the Great Waters program that
focuses on mass balance work, modeling and monitoring support,
control technologies and strategies, and development of assessment
methods that can be used to evaluate waterbodies other than the Great
Lakes. The purpose of such a strategy is to avoid duplication of effort in
funded research and to target specific areas where research is needed to
respond to the mandate of the Great Waters program. In addition,
EPA's Mercury Task Force is in the process of developing an Agency
research strategy specific to mercury. This effort will be fully
coordinated with the Great Waters program.
b. EPA will continue to work with NOAA to pursue the
development and application of the appropriate technical tools to
further define and estimate loadings to the Great Waters and to
identify sources of atmospherically deposited pollutants.
The Great Waters program continues to fund NOAA's development of
transport and deposition models, as well as work to parameterize
important atmospheric processes for those models. These efforts are
exemplified by the development and application of ammonia and
organic nitrogen measurement methods which will aid in
understanding the effects, transport, and sources of various species of
nitrogen. NOAA also assisted in the development of EPA's long-range
transport analyses for mercury.
c. Through the use of Great Waters program funds and other
resources, EPA will continue to support those research activities
identified as priorities by the research communities and affirmed by
the Great Waters Core Project Management Group.
Funding of appropriate research activities is an ongoing effort. As
mentioned above, EPA will continue to identify and evaluate research
priorities during development of a Great Waters program research
strategy.
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Recommended Action
Status
EPA will continue work on the characterization of processes and
parameters for mass balance modeling and the verification of the
mass balance methodology, especially the development of the
prototype mass balance program being conducted in Lake
Michigan.
EPA will work with state agencies to complete regional emission
inventories for the Great Lakes and will complete a national
screening level emission inventory for section 112(c)(6) chemicals
(seven of the Great Waters pollutants), and will identify
categories of sources of these pollutants.
EPA will continue source characterization and identification
activities.
EPA has developed and funded, in cooperation with a number of other
agencies and organizations, the Lake Michigan Mass Balance Study
(LMMB). The LMMB is intended to develop the predictive capability to
determine the environmental benefits of specific load reduction
scenarios and the time needed to realize those benefits. For this study,
the atmospheric deposition of toxics is being monitored and the
concentrations of toxics in fish, phytoplankton, sediment, tributaries are
being measured. Pollutants chosen for the LMMB are total mercury,
atrazine, trans-nonachlor, and PCBs.
Continuation of the Great Lakes regional emission inventory work is
made possible by EPA CAA section 105 grants to the Great Lakes states,
and for the section 112(c)(6) project by Great Waters contract funding.
Four states completed a pilot study of major urban areas along the shore
of Lake Michigan in December 1995 using RAPIDS. Work is continuing
by all of the Great Lakes states to now build a comprehensive regional
air toxics inventory for 49 air pollutants. Mobile source emissions will be
added to the emissions inventory in the future.-EPA's inventory for
section 112(c)(6) of the CAA was made publicly available for comment in
October 1996. The final 112(c)(6) inventory and listing decisions will be
completed by December 1997. The draft inventories can be obtained
from EPA's Internet website at:
www.epa.gov/oar/oaqps/airtox/112c6fac.html.
Source characterization work is ongoing in several areas, ranging from
regulatory work by EPA under CAA section 112 to inventory
development by state agencies. Other specific projects to characterize
and identify emission sources include the Mercury Stack Testing Project
in the Lake Superior Basin which will provide speciated mercury data
for a number of different source types. Also, the Lake Michigan Urban
Air Toxics Study (LMUATS) and the Atmospheric Exchange Over Lakes
and Oceans Study (AEOLOS) focused on the southern Lake Michigan
area to quantify and characterize wet and dry depositional fluxes of
trace metals, PCBs, and PAHs resulting from emission sources in this
urban area.
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Recommended Action
Status
- EPA will complete and evaluate mercury screening level
deposition models using screening emission inventories and will
determine whether to transfer the method to other chemicals
and to provide support for other more intensive regional air
emission inventory efforts.
- EPA will continue to support ongoing monitoring efforts.
EPA has performed and documented extensive mercury deposition
modeling in the draft Mercury Study Report to Congress. Work is
ongoing, as mentioned above, in transferring this methodology to other
chemicals, notably POM, dioxin, and cadmium, on a regional scale using
the REMSAD model. During 1997, these efforts will focus on multi-
pollutant modeling on a regional scale.
EPA continues to support the Integrated Atmospheric Deposition
Network (IADN). The network began collecting data in 1990.
Currently, there are three master monitoring stations in the United
States and two master monitoring stations in Canada. Other satellite
sites have also been added in both countries. Data collection has
proceeded at all sites, and research and development of sampling and
analytical methodologies is ongoing. A workshop to discuss the results
of the IADN work to date will be held in June 1997.
d. EPA will initiate discussions among the appropriate groups to
identify ongoing benefits analysis efforts and human health (cancer
and noncancer) and environmental risk assessment efforts within
the Agency, in other federal programs, in other countries, in
academia, and elsewhere. The goal is to define more clearly the
research/data needs and to develop a long-term plan for developing
tools and methods for benefits analyses and risk assessments.
This activity will be initiated in 1997.
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TABLE A-2
Emission Standards Addressing Great Waters Pollutants of Concern
Standard
Asphalt Hot-Mix Production
Asphalt Roofing Production
Battery Production
Carbamate Insecticides Production
Carbon Reactivation Furnaces
Carbon Black Production
Chlorine Production
Chlorinated Solvents Production
Coke Ovens: Charging, Topside & Door Leaks
Coke Ovens: Pushing, Quenching & Battery Stacks
Commercial Coal Combustion
Commercial Natural Gas Combustion
Commercial Oil Combustion
Commercial Wood/Wood Residue Combustion
Crematories
Dental Preparation and Use
Drum and Barrel Reclamation
Electrical Apparatus Manufacturing
Ferroalloy Manufacture
Fluorescent Lamp Recycling
Gasoline Distribution (Aviation)
Gasoline Distribution (Stage I)
Gasoline Distribution (Stage II)
General Laboratory Activities
Geothermal Power
Hazardous Waste Incineration
Industrial Coal Combustion
Industrial Natural Gas Combustion
Industrial Oil Combustion
Industrial Stationary 1C Engines - Diesel
Pollutants Controlled
Polycyclic organic matter (POM)
POM
Mercury
POM
Dioxin
Mercury, POM
Mercury
Hexachlorobenzene
POM
POM
Mercury, POM
POM
Mercury, POM
POM
Mercury, POM
Mercury
Dioxins, POM
Mercury
POM
Mercury
Lead
Lead, POM
Lead, POM
Mercury
Mercury
Dioxins, mercury, PCBs, POM
Mercury, POM
POM
Mercury, PCBs, POM
POM
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TABLE A-2
Emission Standards Addressing Great Waters Pollutants of Concern
Standard
Industrial Stationary 1C Engines - Natural Gas
Industrial Waste Oil Combustion
Industrial Wood/Wood Residue Combustion
Instrument Manufacturing
Iron and Steel Foundries
Lamp Breakage
Landfill (Gas) Flares
Lightweight Aggregate Kilns
Lime Manufacturing
Medical Waste Incineration
Municipal Waste Combustion
Naphthalene - Miscellaneous Uses
Naphthalene Production
Naphthalene Sulfonates Production
Non-Residential Wood Combustion
Non-Road Vehicles and Equipment (NRVE) - Aircraft
NRVE - Other
On-Road Vehicles
Open Burning of Scrap Tires
Other Biological Incineration
Pesticides Application
Pesticides Manufacture
Petroleum Refining-Catalytic Cracking Units
Phthalic Anhydride Production
Portland Cement Manufacture: Hazardous Waste Kilns
Portland Cement Manufacture: Non-Hazardous Waste Kilns
Primary Aluminum Production
Primary Copper Production
Primary Lead Smelting
Pulp and Paper - Kraft Recovery Furnaces
Pollutants Controlled
POM
POM
Dioxins, POM
Mercury
Dioxins, POM
Mercury
Dioxins, mercury
Dioxins, mercury
Mercury
Cadmium, dioxins, mercury, PCBs, POM
Cadmium, dioxins, mercury, PCBs, POM
POM
POM
POM
Mercury
POM
Lead, POM
Dioxins, POM
POM
Dioxin, PCBs, POM
Hexachlorobenzene
Hexachlorobenzene
POM
POM
Dioxins, mercury, POM
Dioxins, mercury, POM
POM
Cadmium, mercury
Mercury
Dioxins, POM
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TABLE A-2
Emission Standards Addressing Great Waters Pollutants of Concern
Standard
Pulp and Paper - Lime Kilns
Pulp and Paper - Sulfite Recovery Furnaces
Residential Coal Combustion
Residential Natural Gas Combustion
Residential Oil Combustion
Residential Wood Combustion
Scrap or Waste Tire Incineration
Secondary Aluminum Smelting
Secondary Copper Smelting
Secondary Lead Smelting
Secondary Mercury Production
Sewage Sludge Incineration
Stationary Gas Turbines - Diesel
Stationary Turbines - Natural Gas
Utility Coal Combustion
Utility Natural Gas Combustion
Utility Oil Combustion
Wildfires and Prescribed Burning
Wood Treatment/Wood Preserving
Pollutants Controlled
POM
POM
Dioxins, mercury, POM
POM
Dioxins, mercury, POM
Dioxins, POM
Dioxins, PCBs, POM
Dioxins
Dioxins
Dioxins, POM
Mercury
Dioxins, mercury, PCBs, POM
POM
POM
Dioxins, mercury, POM
POM
Dioxins, mercury, PCBs, POM
Dioxins, POM
Cadmium, dioxins, POM
A-19
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APPENDIX B
FISH CONSUMPTION ADVISORIES
As summarized in Chapter II of this report, fish advisory data for each state are collected
in a national data base. The information in the data base available for use in this report was
current through 1995 (U.S. EPA 1996b). For each advisory, the data base contains information
such as waterbody name, waterbody type (e.g., estuary, Great Lake, river), pollutant name, fish
species, population targeted by the advisory (called advisory type in this report), advisory status
(e.g., active), and a state contact name and telephone number. The data base does not, however,
contain information on the levels of pollutants in fish or the benchmark levels set by a particular
state for each advisory type.
For this report, EPA reviewed the data base for any active fish advisories related to the 15
Great Waters pollutants of concern in the Great Lakes, Lake Champlain, Chesapeake Bay, and
several coastal waters.1 (The data base does not include in its list of pollutants three of the Great
Waters pollutants of concern: cc-HCH, nitrogen, and TCDF (furans).) Other criteria used to
select fish advisory data for this report include:
• This report includes advisory data only for those Great Waters pollutants of
concern listed by name in the data base. For example, "metals" is a pollutant
included in the data base, but this report includes advisories associated only with
specific listings for the metals "cadmium," "lead," and "mercury."
• For the Great Lakes, only advisories for which the waterbody type was designated
in the data base as "Great Lake" are included. For example, the waterbody type
for an entire Great Lake (e.g., Lake Huron) and for portions of the lake (e.g.,
Saginaw Bay) are designated as "Great Lake," as are the major Great Lakes
connecting channels (e.g., Detroit River). Note, however, that the tables of fish
consumption advisories in Section II.A of this report contain only lakewide
advisories. Table B-l, below, includes the advisories for tributaries or portions of
the waterbody that were designated as "Great Lake," as well as lakewide
advisories.
• The advisories for coastal waters represent the advisories as they are identified in
the data base. Therefore, advisories for some coastal waters represent the entire
waterbody (e.g., Tampa Bay), while others represent smaller estuaries or portions
of the waterbody (e.g., Baltimore Harbor). Table B-l provides details on the
waterbodies that represent the coastal water advisories. The coastal waters for
which advisory data are presented in this report represent only a small sample of
coastal waters for which there are fish consumption advisories.
• This report does not include statewide advisories. Florida, Massachusetts, Maine,
New Jersey, New York, and Rhode Island all have issued statewide advisories,
which are reported in the data base, that may affect the Great Waters (e.g.,
Narragansett Bay in Rhode Island).
1 The data base contains fish advisory data for numerous other pollutants and several pollutant mixtures (e.g.,
metals, organic compounds, pesticides) other than the Great Waters pollutants of concern. In addition, all U.S.
waterbodies in which there are fish advisories are included in the data base, not only the Great Waters.
B-l
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APPENDIX B
FISH CONSUMPTION ADVISORIES
Section II.A of this report discusses the five main types of advisories included in the fish
advisory data base. Data on informational health advisories, no-kill zones, and commercial
fishing bans are summarized in Chapter II and are not repeated in this appendix. This appendix
provides detailed information on the advisories to limit fish consumption and those to restrict
fish consumption.
This detailed fish consumption advisory information is summarized in Table B-l for the
Great Lakes, Lake Champlain, Chesapeake Bay, and other selected coastal waters. This
information was used to develop the fish consumption advisory tables in Section II.A of this
report. For each waterbody, Table B-l presents the state issuing the advisory, the relevant Great
Waters pollutants of concern, the fish species affected by the advisory, and the advisory type.
The two types of fish consumption advisories (limit fish consumption and restrict fish
consumption) are issued for two different populations (the general population and
subpopulations potentially at risk), resulting in four categories of fish consumption advisories:
• Advisories to subpopulations potentially at risk to restrict the size and frequency
of meals of particular species (RSP);
• Advisories to the general population to restrict the size and frequency of meals of
particular species (RGP);
• Advisories to subpopulations potentially at risk (e.g., pregnant or nursing women,
small children) to not consume particular species (NCSP); and
• Advisories to the general population to not consume particular species (NCGP).
For the most recent fish advisory data for waterbodies in a particular state or for more
details on how the state sets its advisories, the state office responsible for coordinating the fish
advisory program in that state should be contacted.
TABLE B-1
Fish Consumption Advisories in the Great Waters
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
GREAT LAKES
Lake Erie
Ml
OH
PA
Maumee Bay (OH)
PCBs
PCBs
Chlordane, PCBs
PCBs
Carp, catfish
Carp, channel catfish, chinook salmon > 19",
coho salmon, freshwater drum, lake trout,
smallmouth bass, steelhead trout, walleye,
white bass, white perch
Carp, channel catfish, lake trout
Channel catfish
Carp
NCGP
RGP
NCGP
NCGP
RGP
B-2
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APPENDIX B
FISH CONSUMPTION ADVISORIES
TABLE B-1
Fish Consumption Advisories in the Great Waters (continued)
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
Lake Huron
Ml
Saginaw Bay (Ml)
Chlordane, dioxins
PCBs
Chlordane
Dioxins
PCBs
Lake trout > 22"
Lake trout < 22"
Lake trout > 22"
Brown trout > 21", lake trout
Lake trout > 22"
Lake trout > 22"
Carp, channel catfish, lake trout > 22"
Brown trout > 21", lake trout > 22"
NCGP
NCSP, RGP
NCGP
NCSP, RGP
NCGP
NCGP, NCSP,
RGP
NCGP
NCSP, RGP
Lake Michigan
IL
IN
Ml
Wl
Green Bay (Ml)
Green Bay (Wl)
Little Bay de Ngoc
(Ml)
Chlordane, PCBs
PCBs
Chlordane
Mercury
PCBs
Chlordane
PCBs
PCBs
PCBs
Mercury
PCBs
Brown trout > 23", chinook salmon > 32", lake
trout > 23"
Brown trout < 23", chinook salmon 21-32",
coho salmon > 26", lake trout 20-23"
Brown trout > 23", carp, catfish, chinook
salmon > 32", lake trout > 23"
Brown trout < 23", chinook salmon 21-32",
coho salmon > 26", lake trout 20-23"
Lake trout > 23", lake whitefish > 23"
Lake trout 20-25"
Walleye > 22"
Brown trout > 23", carp, channel catfish
Lake trout > 23"
Lake trout > 23"
Lake trout 20-23"
Brown trout > 23", carp, catfish, chinook
salmon > 32", lake trout > 23"
Brown trout < 23", chinook salmon 21-32",
coho salmon > 26", lake trout 20-23"
Brook trout > 15", brown trout > 21", carp,
northern pike > 28", rainbow trout > 22", splake
trout > 20", sturgeon, walleye > 20", white bass
Brown trout < 21", splake trout < 20"
Brook trout > 15", brown trout > 12", carp,
chinook salmon > 25", northern pike > 28",
rainbow trout > 22", splake trout > 16", walleye
> 20", white bass
Splake trout < 16"
Walleye > 22"
Brown trout > 23", carp, channel catfish
Lake trout > 23", lonqnose sucker > 16"
NCGP
NCSP, RGP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
RGP, RSP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
RGP, RSP
NCGP
NCSP, RGP
B-3
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APPENDIX B
FISH CONSUMPTION ADVISORIES
TABLE B-1
Fish Consumption Advisories in the Great Waters (continued)
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
Lake Michigan (continued)
Old North Harbor,
Waukegan (IL)
Chlordane, PCBs
Alewife, carp
NCGP
Lake Ontario
NY
Irondequoit Bay
(NY)
Dioxins, PCBs
PCBs
American eel, carp, channel catfish, chinook
salmon, lake trout, white perch
Brown trout > 20", coho salmon > 21", rainbow
trout > 25"
Brown trout, coho salmon, rainbow trout, white
sucker
Brown trout < 20", coho salmon < 21", rainbow
trout < 25", white perch, white sucker
Carp
NCGP, NCSP
NCGP
NCSP
RGP
NCGP, NCSP
Lake Superior
Ml
MN
Wl
Chequamegon
Waters (Wl)
Thunder Bay (Ml)
Chlordane, mercury,
toxaphene
PCBs
PCBs
Chlordane
Mercury
PCBs
Mercury
Chlordane, dioxins
PCBs
Ciscowet> 18"
Ciscowet > 18", lake trout > 30"
Lake trout 20-30"
Ciscowet > 20"
Brown trout, chinook salmon, coho salmon,
ciscowet < 20", lake herring, lake trout, lake
whitefish, rainbow trout
Ciscowet > 20"
Walleye 26-30"
Walleye 18-26"
Walleye < 18"
Ciscowet > 20", lake trout > 30"
Largemouth bass 15-18"
Northern pike > 30"
Largemouth bass < 15", northern pike < 30"
Lake trout > 22"
Lake trout < 22"
Lake trout > 22"
Brown trout > 21", carp, lake trout < 22"
NCGP
NCGP
NCSP, RGP
NCGP
RGP
NCGP
NCGP
NCSP, RGP
RSP
NCGP
NCGP
NCSP, RGP
RSP
NCGP
NCSP, RGP
NCGP
NCSP, RGP
B-4
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APPENDIX B
FISH CONSUMPTION ADVISORIES
TABLE B-1
Fish Consumption Advisories in the Great Waters (continued)
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
Connecting Channels
Detroit River (Ml)
Lake St. Clair(MI)
Niagara River
(NY)
St. Clair River (Ml)
St. Lawrence
River (NY)
St. Mary's River
(Ml)
Mercury
PCBs
Mercury
PCBs
Dioxins, PCBs
PCBs
Mercury
PCBs
Dioxins, PCBs
PCBs
Mercury
Freshwater drum > 14"
Carp
Muskellunge, sturgeon
Bluegill sunfish > 8", brown bullhead catfish >
14", carpsucker > 18", freshwater drum > 14",
largemouth bass, northern pike > 26", rock
bass > 8", smallmouth bass > 18", walleye >
20", white bass > 13", white perch > 10"
Channel catfish > 22"
Carp > 22"
American eel, carp, channel catfish, chinook
salmon, lake trout, white perch
Brown trout > 20", coho salmon > 21", rainbow
trout > 25"
Brown trout, coho salmon, rainbow trout,
smallmouth bass, white sucker
Brown trout < 20", coho salmon < 21", rainbow
trout < 25", smallmouth bass, white sucker
Carp
Freshwater drum > 14"
Carp > 21", gizzard shad > 10"
American eel, carp, channel catfish, chinook
salmon, lake trout
Brown trout > 20", coho salmon > 21", rainbow
trout > 25"
Brown trout, coho salmon, rainbow trout
White perch
Brown trout < 20", coho salmon < 21", rainbow
trout < 25"
Fish
Walleye > 19"
RGP, RSP
NCGP
NCGP
RGP, RSP
NCGP
NCSP, RGP
NCGP, NCSP
NCGP
NCSP
RGP
RGP
RGP, RSP
NCSP, RGP
NCGP, NCSP
NCGP
NCSP
NCSP, RGP
RGP
NCGP, NCSP
RGP, RSP
LAKE CHAMPLAIN
NY
VT
Mercury
PCBs
Mercury
PCBs
Walleye > 19"
Brown bullhead, eel, lake trout > 25", yellow
perch
Walleye
Lake trout > 25"
NCSP, RGP
NCSP, RGP
NCSP, RGP
NCSP, RGP
B-5
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APPENDIX B
FISH CONSUMPTION ADVISORIES
TABLE B-1
Fish Consumption Advisories in the Great Waters (continued)
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
SELECTED COASTAL WATERS
Chesapeake Bay
Anacostia River/
Potomac River
(DC)
Back River (MD)
Baltimore Harbor
(MD)
Lake Roland,
Jones Falls (MD)
Chlordane, PCBs
Chlordane
Chlordane
American eel, carp, channel catfish
American eel, channel catfish
Black crappie, carp
RGP
RGP
RGP
Delaware Bay
Delaware Estuary
(DE)
Delaware River
and Delaware
Estuary (PA)
PCBs
Chlordane, PCBs
Channel catfish, striped bass, white catfish,
white perch
Channel catfish, striped bass, white catfish
American eel, channel catfish, white perch
NCGP
RGP, RSP
NCGP
Galveston Bay
Houston Ship
Channel (TX)
Dioxins
Blue crab, catfish
NCSP, RGP
Long Island Sound
CT
NY
PCBs
Chlordane
PCBs
Bluefish > 25", striped bass
Striped bass
Striped bass
NCSP, RGP
RGP
NCGP
NY/NJ Harbor
Arthur Kill (NJ),
Kill van Kull(NJ)
Newark Bay (NJ)
Raritan Bay (NJ),
Raritan River (NJ),
Sandy Hook Bay
(NJ)
Tidal Passaic
River (NJ)
Dioxins
PCBs
Dioxins
PCBs
Dioxins
PCBs
Dioxins
PCBs
Blue crab, striped bass
American eel, bluefish > 24" > 6 Ibs, striped
bass, white catfish, white perch
Blue crab, striped bass
Bluefish > 24" > 6 Ibs, striped bass
White catfish, white perch
Bluefish > 24" > 6 Ibs, striped bass
Blue crab
American eel, bluefish > 24" > 6 Ibs, striped
bass, white catfish, white perch
Crustaceans, fish, shellfish
Striped bass
American eel, bluefish > 23" > 6 Ibs, white
catfish, white perch
NCGP, NCSP
NCSP, RGP
NCGP, NCSP
RGP
NCSP, RGP
NCSP
RGP, RSP
NCSP, RGP
NCGP, NCSP
NCGP, NCSP
NCSP, RGP
B-6
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APPENDIX B
FISH CONSUMPTION ADVISORIES
TABLE B-1
Fish Consumption Advisories in the Great Waters (continued)
Waterbody3
Great Waters
Pollutant of Concern
Fish Species
Advisory
Type"
San Francisco Bay
San Francisco
Bay delta region
(CA)
Tampa Bay (FL)
Dioxins, DDT, mercury,
PCBs
Mercury
Striped bass > 35"
Sharks > 24", striped bass > 27"
Fish except anchovy, herring, salmon, and
smelt
Crevallejack, gafftop sail catfish, ladyfish,
Spanish mackerel
NCGP
NCSP
RGP, RSP
RGP, RSP
a For the Great Lakes, the advisories are listed first by lakewide advisories, in alphabetical order by state,
followed by portions of the waterbody and major tributaries that were designated in the data base as "Great
Lake." Lake Champlain advisories are all lakewide. For coastal waters, including Chesapeake Bay, the
advisories are presented by how the coastal water was designated in the data base, which may be by full name
or by waterbody portion.
b NCGP = advises against consumption by the general population
NCSP = advises against consumption by subpopulations potentially at risk (e.g., pregnant or nursing women,
small children)
RGP = advises the general population to restrict size and frequency of meals of the particular species
RSP = advises subpopulations potentially at risk to restrict size and frequency of meals of the particular
species
Source: U.S. EPA1996b.
B-7
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