xvEPA
United States Office of Air Quality EPA-453/R-93-055
Environmental Protection Planning and Standards May 1994
Agency Research Triangle Park, NC 27711
Deposition of Air Pollutants
to the Great Waters
First Report to Congress
Printed on Recycled Paper
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Cover photo credits:
J. Scott Taylor,
Duke University Marine Lab
International Joint
Commission
International Joint Commission
James F. Parnell
Jamey Tidwell,
Texas Sea Grant
International Joint Commission
International Joint Commission
University
of Michigan
University of Michigan
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"Copies of the firstReport to Congress, Deposition of Air Pollutants to the
Great Waters, can be obtained, as supplies permit, from the Library Services
Offices (MD-35), U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina 27711, or, for a nominal'fee, from the National
Technical Information Service', 528S Port Royal Road, Springfield, Virginia
22161, phone: 1-800-553-NTIS or 703-487-4650.
• Information in' this Report to Congress has been derived mainly from three
detailed background reports prepared by committees of leading independent
scientists. These committees were convened by EPA to summarize the
current state of scientific knowledge on atmospheric deposition "to'the Great
Waters. Unless otherwise referenced, all scientific information in this report
is drawn from the three technical contractor reports:
1. Relative Atmospheric Loadings of Toxic Contaminants and Nitrogen
• to the Great Waters, 1993. Describes the mass balance approach for
determining inputs into surface water. Discusses waterbody-speeific
mass balance calculations for several pollutants.
2. Identification of Sources Contributing to the Contamination of the
Great Waters by Toxic Compounds. 1993. Describes techniques for
source identification. Discusses the importance of local, regional,
and distanlsourees for atmospheric deposition to the Great Waters.
3. Exposure, and Effects of Airborne Contamination. 1992. Provides a
detailed summary, of the ecological and human health effects of
, selected air pollutants of concern for deposition to the Great Waters.
Copies of these reports can be obtained by writing:
Office of Air Quality Planning and Standards
Pollutant Assessment Branch (MD-13)
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Attention: Great Waters Documents
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Contents
Executive Summary
IX
1. Introduction 1
Section 112(m) of the Clean Air Act, as Amended in 1990 4
Report Objectives 8
Report Preparation 8
2. Overview of the Great Waters Program 11
3. Answering the Scientific Questions
of Section 112(m) 17
Effects: What Human Health and Environmental Effects Are
Associated with Exposure to Great Waters Pollutants of Concern? 18
Relative Loading: What Is the Relative Importance
of Atmospheric Deposition in Loadings to the Great Waters? 45
Sources: What Sources Are Significant Contributors
to Atmospheric Loadings to the Great Waters? 56
4. Conclusions and Recommendations
Conclusions
Recommendations and Actions
5. References
Appendices
Appendix A:
Lists of Bioaccumulative Chemicals of Concern and
Potential Bioaccumulative Chemicals of Concern
Appendix B: Comparison of Great Lakes Sampling Data
to Various Water Quality Benchmarks
Appendix C: Historical EPA Regulations
Appendix D: Summary of Clean Air Act Section 112 Activities
Appendix E: Progress Under Section 112(m)
Appendix F: Summary of MACT Source Categories Potentially
Emitting Great Waters Pollutants of Concern
Appendix G: Preliminary Summary of Research Needs
and Program Planning
67
68
73
83
A-l
B-l
C-l
D-l
E-l
F-l
G-l
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List of Figures
1. Locations of designated Great Waters 5
2. How does atmospheric deposition occur? 12
3. Significant milestones in understanding atmospheric deposition
of toxic air pollutants to aquatic ecosystems 13
4. Distribution of pollutants within a waterbody 21
5. Simplified overview of a food web in the Great Lakes 22
6. The eutrophication process 32
7. Biomagnification of PCBs in the Lake Ontario food web, 1982 40
8. U.S. daily intakes of methylmercury versus World Health
Organization "Safe Levels" 41
9. Mass balance model for lakes and estuaries 45
10. Mass balance of PCBs in Lake Superior 49
11. Mercury in Little Rock Lake, WI 52
12. Annual nitrogen loadings to Delaware Bay 53
13. Cadmium loadings to Delaware Bay 53
14. Atmospheric loading of PCBs to the Great Lakes 54
15. Examples of sources 56
16. Pollutants of concern emitted from selected sources 58
17. Sources of PAH emissions in eastern North America, 1992 62
18. Anthropogenic sources of nitrogen oxide emissions in 1990 63
iv
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List of Tables
1. Major Activities and Questions Addressed by the Great Waters Program 14
2. Selected Pollutants of Concern in the Great Waters 19
3. Current Great Lakes Fish Consumption Advisories 26
4. Current Fishing Advisories in Selected Great Waters 27
5. Potential Human Health Effects Associated with Pollutants
of Concern 33
6. Explanation of Atmospheric Deposition Terms 47
7. Contribution of Atmospheric Deposition to Total Loadings
of Pollutants of Concern for Selected Waterbodies 55
8. Contribution of Atmospheric Deposition to Total, Loadings
of Nitrogen for Selected Waterbodies 55
9. U.S. Sources of Air Pollutants of Concern 59
10. Source Apportionment Techniques 61
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Abbreviations and Acronyms
AAs Assistant Administrators
ACTs Achievable control technology documents
ANPR Advance notice of proposed rulemaking
AWQC Ambient water quality criterion or criteria
BCCs Bioaccumulative chemicals of concern
CWA Clean Water Act
DDE Dichlorodiphenyldichloroethylene
DDT Dichlorodiphenyltrichloroethane
EPA U.S. Environmental Protection Agency
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
g Gram
GLWQA Great Lakes Water Quality Agreement
GLWQB Great Lakes Water Quality Board
GLWQO Great Lakes Water Quality Objective
HAP Hazardous air pollutant
HCH Hexachlorocyclohexane
IJC International Joint Commission
kg Kilogram
L Liter
LQER Lesser-quantity emission rates
MACT Maximum achievable control technology
MCL Maximum contaminant level
m3 Cubic meter
mg Milligram
NEP National Estuary Program
NERRS National Estuarine Research Reserve System
ng Nanogram
NOAA National Oceanic and Atmospheric Administration
NOX Oxides of nitrogen
NPDES National Pollutant Discharge Elimination System
PAH Polycyclic aromatic hydrocarbon .
PCB Polychlorinated biphenyl
pGLWQC Proposed Great Lakes water quality criteria
POM Polycyclic organic matter
ppb Parts per billion
ppm Parts per million
ppt Parts per trillion
RAs Regional Administrators
TCDD Tetrachlorodibenzo-p-dioxin
TCDF Tetrachlorodibenzofuran
TSCA Toxic Substances Control Act
WHO World Health Organization
yr Year
VI
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Acknowledgments
The EPA would like to acknowledge the significant contribution
that was made in the development of this report by the scientific com-
munity. The authors of the three background documents, upon which
the scientific content of this Report to Congress is based, prepared these
documents in a difficult time frame and worked long hours to revise
them in response to peer review comments. These author teams were:
Relative Loadings
Joel E. Baker, University of Maryland
Thomas M. Church, University of Delaware
Steven J. Eisenreich, University of Minnesota
William K. Fitzgerald, University of Connecticut
Joseph R. Scudlark, University of Delaware
Source Identification
Gerald J. Keeler, University of Michigan
Jozef M. Pacyna, University of Michigan
Terry F. Bidleman, Atmospheric Environment Service
Jerome 0. Nriagu, Environment Canada
Effects
Wayland R. Swain, Eco Logic International, Inc.
Theo Colborn, World Wildlife Fund
Carol Bason, World Wildlife Fund
Robert W. Howarth, Cornell University
Lorraine Lamey, Eco Logic International, Inc.
Brent D. Palmer, Ohio University, Athens
Deborah L. Swackhamer, University of Minnesota.
Also, EPA would like to express appreciation to the wider commu-
nity of scientists, both within and outside the Agency, who participated
in the workshop to discuss and evaluate the draft technical background
reports and to all of the participating scientists for their efforts in
reviewing drafts of Chapter 3 of this Report to Congress.
In addition, many employees throughout the EPA have made
significant contributions to this Report to Congress.
vii
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Executive Summary
Pollutants emitted into the atmosphere are transported various
distances and can be deposited to aquatic ecosystems far removed from
their original sources. Scientific studies show that atmospheric deposi-
tion is often an important factor in the degradation of water quality
and the associated adverse health and ecological effects in studied
waterbodies. In response to the mounting information indicating that
air pollution contributes significantly to water pollution, Congress
included section 112(m), referred to as the Great Waters program,
in the Clean Air Act, as amended in 1990 (1990 Amendments). This
report fulfills the Act's requirement for a Report to Congress 3 years
after enactment.
The purpose of the Great Waters program is to evaluate the
atmospheric deposition of air pollutants to the Great Lakes, Lake
Champlain, Chesapeake Bay, and coastal waters. The report to Con-
gress is to include information on the contribution of atmospheric depo-
sition to pollutant loadings, the environmental or public health effects of
such pollution, the source or sources of such pollution, and a description
of any regulatory revisions under applicable Federal laws that may be
necessary to assure protection of human health and the environment.
The scientific information currently available is summarised in
this report, and recommended actions are described.
Water quality conditions in the Great Lakes and many other
waterbodies are greatly improved compared to a few decades ago, the
result of environmental regulatory programs and public and industrial
cleanup efforts addressing primarily waterborne pollution. However,
despite the improvements, the Great Waters ecosystems are far from
fully recovered, and it is necessary to address the more diffuse sources
of pollution, including the air component, in order to attain water qual-
ity goals and to ensure protection of human health and the environ-
ment.
Pollutants of concern to the Great Waters possess certain common
characteristics. They persist in the environment and, thus, can travel
great distances, often being deposited and reemitted many times. These
pollutants accumulate in the environment, making the potential for
exposure to them greater than for pollutants that readily degrade. The
potential for long-distance transport is evident by the presence of pollut-
ants in remote, pristine environments such as the Arctic.
Pollutants of concern also accumulate in body tissues and magnify
up the food web, with each level accumulating the toxics from its diet
and passing the burden along to the animal in the next level of the food
IX
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Executive Summary
web. Top consumers in the food web, usually consumers of large fish,
may accumulate chemical concentrations many millions of times greater
than the concentrations present in the water. As a result of unsafe con-
centrations of chemicals in fish, due to biomagnification, fish consump-
tion advisories have been issued in hundreds of waterbodies nationwide,
including the Great Lakes. High-risk groups, which fish consumption
advisories are established to protect, include breast-feeding mothers
because breast-fed babies continue to accumulate from their mothers
after birth. For example, they can have PCB levels four times higher
than their mothers after 6 to 9 months of breast-feeding. Other groups at
high risk are subpopulations such as sport anglers, Native Americans,
and the urban poor, who tend to have high fish consumption. EPA and
other agencies are addressing this environmental justice issue by exam-
ining impacts to higher-risk populations and taking this into consider-
ation in regulating activities.
Significant adverse effects on human health and wildlife have been
observed due to exposure, especially through fish consumption, to persis-
tent pollutants that bioaccumulate. Adverse effects range from immune
system disease and reproductive problems in wildlife to subtle develop-
mental and neurological impacts on children and fetuses.
Although most of the chemicals of concern are probable human
carcinogens, many are also developmental toxicants capable of altering
the formation and function of critical body systems and organs. There-
fore, the developing embryo and fetus and breast-fed infants are particu-
larly sensitive to these chemicals.
Ecological effects attributable to pollutants of concern are signifi-
cant~and can be subtle or delayed in onset, such as immune function
impairment., reproductive problems, and neurological changes—all of
which can affect population survival.
Other adverse ecological effects are caused by nitrogen compounds.
Nitrogen compounds from atmospheric deposition exacerbate nutrient
enrichment (or eutrophication) of coastal waterbodies, which results in
impacts that range from nuisance algal blooms to the depletion of oxygen
with resultant fish kills.
Studies show that significant portions of loadings to the Great
Waters of the pollutants of concern are coming from the atmosphere. For
example, 76 to 89 percent of PCBs to Lake Superior and up to 40 per-
cent of nitrogen loadings to the Chesapeake Bay are estimated to come
from air pollution. However, insufficient data are available to generalize
the atmospheric loadings to all waters. Absolute quantities of deposited
pollutants are also important, especially since loadings of even small
amounts of pollutants that bioaccumulate can result in significant pollut-
ant burdens in fish.
Pollutants of concern in the Great Waters originate from sources
that~are local to, as well as distant from, the impacted waters. Transport
distances depend on the characteristics of the chemicals and source
emissions as well as weather patterns. As such, generalizing source
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Executive Summary
identification from one waterbody to another would not be accurate.
More data are needed to determine sources and source categories
affecting the Great Waters.
Uncertainties in current information are significant, and further
research is needed to better characterize the most important information
for decisionmakers. However, adequate information is available to lead
EPA to the conclusion that some actions are justified and necessary at
this time. Adverse effects of the chemicals of concern are evident and
studies of selected waters show significant proportions of toxic pollution
coming from the atmosphere. However, because the linkage between
specific sources and subsequent deposition and effects has yet to be
demonstrated, the kinds of actions described in this report focus on the
chemicals of concern rather than on specific sources.
EPA considered the implications of action and of inaction, while
recognizing that section 112(m) of the 1990 Amendments mandates that
EPA should act to "prevent" adverse effects and to "assure protection of
human health and the environment." EPA's recommendation is that
reasonable actions are justified, based on evaluation of the scientific
information currently available, and should now be taken and that
research should continue. The National Oceanic and Atmospheric
Administration (NOAA) concurs with this recommendation.
Most of the actions EPA will undertake focus on utilizing regula-
tory mechanisms in the Clean Air Act that are intended to address the
most hazardous chemicals. EPA believes that the characteristics of toxic-
ity, persistence, and tendency to bioaccumulate warrant special treat-
ment of the Great Waters pollutants of concern and that this is consis-
tent with congressional intent for those regulatory mechanisms and for
section 112(m).
The recommendations from the report fall into three strategic
themes. First, EPA will continue ongoing efforts to implement section
112 and other sections of the Clean Air Act and use the results of this
report in the development of policy that will reduce emissions of Great
Waters pollutants of concern. Under this theme, EPA will take actions
that include: publishing emission standards affecting important chemi-
cals of concern ahead of schedule, where possible; evaluating the ad-
equacy of control technologies for important pollutants; publishing an
advance notice of proposed rulemaking (ANPR) for establishment of
lesser-quantity emission rates (LQERs) to define smaller sources to be
regulated as "major sources" and evaluating which Great Waters pollut-
ants warrant establishment of an LQER; evaluating which area sources
should be regulated with maximum achievable control technology
(MACT); and considering appropriate emission levels requiring regula-
tion when sources are modified.
Second, EPA recognizes the need for an integrated multimedia
approach to this problem and, therefore, will utilize authorities beyond
the Clean Air Act to reduce human and environmental exposure to
pollutants of concern. Under this theme, EPA will take actions that
XI
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Executive Summary
include using the GreatrWaters Core Project Management Group as a
coordinating body to communicate with other offices/agencies. The
objectives will be to: coordinate work and especially to identify lead
offices to implement recommendations; support changes to the Clean
Water Act that address nonwaterborne sources of water pollution;
address the exportation of banned pesticides; emphasize pollution pre-
vention efforts to reduce environmental loadings of pollutants of concern;
and facilitate information sharing between EPA and other agencies.
Third, EPA will continue to support research activities and will
develop and implement a program strategy to define further necessary
research. Under this theme, EPA will take actions that include: focus-
ing research planning on a mass-balance approach to determine relative
loadings; using an appropriate mix of monitoring, modeling, and emis-
sion inventory tasks in conducting mass-balance work; assessing the
need for tools to be developed for risk assessment for total exposure to
pollutants of concern and for regulatory benefits assessment; and con-
tinuing to support ongoing research efforts.
xil
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Executive Summary
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pie wng regularly consume threat Lakes fish have been found to
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mcreased concentrations ot FLBs in the mother, since
PCBs can cross through the placenta and directly affect
embryos in the womb.* See page 34 for further discussion
of this issue.
• Fish-eating birds, mammals, and reptiles have experi-
enced reproductive problems and a variety of other adverse
effects associated with chemical pollution, leading to popu-
lation declines for many species. Embryo and offspring
mortality have been linked to PCBs and other toxic
chemicals.
• Damage to fish has been linked to chemical pollution,
.iacludmg effecMon hormone fraction, immune system
response, and enzyme activity. Several studies have
reported the occurrence of cancer and other toxic effects in
bottom-feeding fish in tributaries and harbors of the Great
Lakes.
-
• Commercial fishing has been closed or restricted in
portions of all five Great Lakes at various times in recent
years because of toxic chemical pollution, and restrictions
are still in place for many fish species. Numerous health
advisories have been issued to discourage consumption of
certain fish caught in the Great Lakes.
*PCB concentrations in fish have decreased since the 1970s.
However, fish consumption advisories exist for certain types of
fish in specific lakes due to current PCB concentrations in the
fish.
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Chapter One
Introduction
Evidence for
Long-Distance
Atmospheric Transport
• Chemicals from anthropogenic
sources (i.e., created by hu-
mans) are present in Arctic
and Antarctic ecosystems,
thousands of miles from likely
emission sources.
• Lead and other trace metals
have been measured in air
and rainfall at remote loca-
tions over the Atlantic and
Pacific Oceans, thousands of
miles from likely sources.
• European research suggests,
that the major sources of trace
metals and persistent organic
chemicals deposited from air
into the Baltic Sea are located
hundreds of miles away.
amounts in the United States since the 1970s, have become widely dis-
tributed in the environment and are now, in essence, part of the global
"background." These toxic chemicals remain in our environment and
continue to cycle between air, water, soil, and biota (living organisms),
even after their manufacture, use, or release has stopped.
A number of recent field studies have demonstrated that air pollu-
tion is an important contributor to chemical pollution of U.S. lakes and
coastal waters. Some of these studies are described below.
• Air and rainfall in the Great Lakes region, the Chesapeake Bay
watershed, and other areas have repeatedly been shown to be
contaminated with a variety of toxic chemicals. PCBs, for
example, are present in the air above all five Great Lakes and
are also present (at roughly similar levels) in the air above
Chesapeake Bay. PCB levels either currently exceed or have
recently exceeded water quality standards in portions of all of
the Great Lakes (see appendix B).
• A recent series of studies of Wisconsin lakes indicate that the
air is a major contributor of mercury to these lakes and that
modest increases in atmospheric deposition of mercury could
lead directly to higher levels of mercury in fish. These studies
are in broad agreement with research on mercury deposition to
Swedish lakes.
• Studies of fish from Siskiwit Lake-a small lake on an island
in northern Lake Superior that is isolated from most human
influences - have shown contamination with PCBs, toxaphene,
and other pesticides, which have no known sources on the
island. Toxaphene, a pesticide banned in the United States in
1982, had limited use in the Lake Superior region but was used
heavily in the southeastern U.S. Cotton Belt from the late
1960s to the mid-1970s. This use pattern indicates that tox-
aphene was probably transported by air from the Southeast to
the Great Lakes region. Airborne levels of toxaphene are high-
est in the southeastern U.S. and decline with distance as one
moves toward the Great Lakes and north Atlantic regions.1
• It is likely that other pesticides present in the Great Lakes,
including DDT, are transported long distances by air, from
itheir sources to the Great Lakes region.2 Based on the amount
and chemical form of DDT present in core samples from peat
bogs in the Great Lakes region, new releases of DDT are appar-
ent and may be originating from sources outside the United
States, possibly Mexico and Central America.2 Atmospheric
deposition of DDT, toxaphene, hexachlorobenzene, and PCB
levels in the Great Lakes region, as measured in peat cores, are
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Chapter One
Introduction
The Clean Air Act establishes
research, reporting, and regulatory
requirements related to atmos-
pheric deposition to the Great
Waters, including a mandate that
EPA, in cooperation with the
National Oceanic and Atmospheric
Administration, submit a Report
to Congress in 1993 and every
2 years thereafter.
consistent with the U.S. production and use history of these
chemicals.3
• Long-term sampling of precipitation falling onto coastal waters
near Lewes, Delaware, indicates that concentrations of most
trace metals in rainfall have been fairly constant in recent
years and are far greater than concentrations in most surface
waters. A notable exception is the concentration of lead in
rainfall, which has declined since the major reduction in use of
leaded gasoline in the United States in the mid-1980s.4
• Various forms of nitrogen, a nutrient that can cause undesir-
able effects in coastal marine waterbodies when present in
excessive amounts, have been measured in rain falling on
Chesapeake Bay and its watershed. A significant fraction of
the total nitrogen entering Chesapeake Bay (28 to 40 percent)
and several other estuaries is believed to come from atmos-
pheric deposition.
Eecent monitoring studies conclude that the air is supplying
approximately 77-89, 63, and 58 percent of the PCBs currently entering
Lakes Superior, Huron, and Michigan, respectively. Atmospheric input
accounts for more than 95 percent of the lead entering these water-
bodies. Overall, scientists estimate that 35 to 50 percent of current
yearly inputs of a variety of toxic chemicals to the Great Lakes may be
from the air. Similar studies indicate that atmospheric deposition is an
important source of metals, polycyclic aromatic hydrocarbons (PAHs,
a subgroup of polycyclic organic matter), PCBs, and nitrogen com-
pounds to Chesapeake Bay. Monitoring studies, along with direct mea-
surements of pollutants entering waterbodies in precipitation, show
that air pollution is not just a theoretical source of the toxic chemicals
present in large lakes and coastal waters but is, in some cases, a
significant contributor to the overall amount of pollution entering
waterbodies (see Tables 7 and 8, page 55, and Figure 11, page 52).
Section 112(m) of the Clean Air Act, as Amended in 1990
Section 112(m) of the 1990 Amendments establishes research and
reporting requirements related to atmospheric deposition of hazardous
air pollutants* to the Great Lakes, Lake Champlain, Chesapeake Bay,
and coastal waters (defined in the statute to include coastal waters in
the National Estuary Program or the National Estuarine Research
*Section ll^m), and therefore this Report to Congress, does not address acid rain. This report addresses pollutants from the section
112(b) list of 189 hazardous air pollutants, along with two other pollutants of concern.
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Chapter One
Introduction
Lake
Superior
Lake
Lake Champlain
Huron Lake
Ontario
Reserve System). Figure I shows the locations of currently designated
Great Waters.
This report focuses primarily on the Great Lakes because much
of the available scientific information on deposition of toxic air pollut-
ants is from studies of the Great Lakes. Where data were available,
studies of the Chesapeake Bay are cited. The Chesapeake Bay is one of
the only coastal waterbodies
for which data exist on atmos-
pheric deposition, loadings,
and effects of nitrogen and
toxic air pollutants. Continuing
research, building on available
information, particularly from
the Great Lakes, is examining
whether information from the
Great Lakes and Chesapeake
Bay is applicable to other
Great Waters.
Section 112(m) directs
EPA, in cooperation with the
National Oceanic and Atmos-
pheric Administration (NOAA),
to assess the extent of atmos-
pheric deposition of hazardous
Chesapeake
Bay
+ Great Waters designated by name
• EPA National Estuary Program (NEP) Sites
• NOAA NERRS Designated Sites*
D Existing EPA and NOAA NERRS Designated Sites
D Existing EPA and NOAA NERRS Proposed Sites
*NOAA=National Oceanic and Atmospheric Administration;
NERRS=National Estuarine Research Reserve System
Figure 1. Locations of
designated Great Waters.
air pollutants to the Great
Waters. As part of this assess-
ment, EPA is to monitor
atmospheric deposition, inves-
tigate sources and deposition
rates, conduct research to
improve monitoring methods
and to determine relative loadings, evaluate human health and environ-
mental effects,* assess violations of water quality standards, and
sample fish and wildlife for atmospherically deposited pollutants. Sec-
tion 112(m) specifically requires that EPA establish atmospheric deposi-
tion monitoring networks in the Great Waters. In addition, EPA must
determine whether the other regulatory programs under section 112 are
"adequate to prevent serious adverse effects to public health and serious
or widespread environmental effects" associated with atmospheric
deposition to the Great Waters. Based on this determination, EPA is
directed to take additional measures that are necessary and appropriate
to prevent serious effects to human health and the environment.
In addition to the above requirements, section 112(m)(5) directs
EPA, in cooperation with NOAA, to submit, by November 1993 and
* Environmental effects include both ecological effects and other welfare effects such as the commercial impacts of depleted fish popula-
tions or lost recreational opportunities.
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>gress,
jeopjaeraHveeliorts of various
ana State
j|jjli|||l^^ |
iss has been made in deposition momtonng.
una stations (one_per lake) are col-___ __|
deposition samples (since 1992)7
.emenlary stationary stations and ship-based intensive coi-
iif'iS™^
:eWchigan, 1993-1996.
earcr
jlain
,. ^^p^-J^y.- deposition
• of nutfienla and hazardous air pollutants (HAPs) in the Lake
"'Champlain basin.
the
Consortium, and ^^ ,
mmiam^^MimmtjimmiK^f^'-i'mff'.m^a^i
erative, in cooperation, are conducting
Chesapeake Bay and Other Coastal Waters
• From 1990-1993, three stations collected wet and dry toxics.
deposition , samples in .the Chesapeake Bay.
• Intensive collection efforts for characterization of urban
plume influence to the Chesapeake Bay are being undertaken.
• NOAA conducts the Atmospheric Nutrient Input to Coastal
Areas (ANICA) program to determine the fraction of coastal
nutrient pollution that comes by way of the atmosphere. So far,
efforts have centered on the northeastern U.S. coast, with a
:_fc!Cua_ODL.Cbjeiapeake Bay, and have been accomplished through
networks. ......
|LKQAA conducts the Atmospheric Integrated Research Moni-
taring Network, which is intended to supply data to atmos-
pheric modelers for evaluating the changes in nitrogen and
other atmospheric contaminants due to legislated emission
reductions. Progress to date includes the establishment of four
daily monitoring stations in or near northeastern U.S. Great
Waters drainage basins.
• A screening-level toxics monitoring effort in Galveston Bay
is collecting various toxics, comparable in method to work in
the Chesapeake Bay.
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Chapter One
Introduction
every 2 years thereafter, a Eeport to Congress on atmospheric deposi-
tion to the Great Waters. The report is to describe "results of any moni-
toring, studies, and investigations conducted pursuant to" section
112(m) and, at a minimum, is to include an assessment of:
• the contribution of atmospheric deposition to pollution of the
Great Waters,
• environmental and human health effects of air pollutants that
are deposited to the Great Waters,
• sources of air pollutants that are deposited to the Great
Waters,
• whether atmospheric deposition contributes to violations of
drinking water standards or water quality standards or
exceedances of Great Lakes Water Quality Agreement objec-
tives, and
• regulatory changes needed to ensure protection of human
health and the environment.
In the 1990 Amendments to the Clean Air Act, Congress placed
special emphasis on mercury as a toxic air pollutant. Several subsec-
tions in section 112 contain special requirements for the study of mer-
cury and the regulation of mercury emissions. Section 112(c)(6) lists
mercury, along with six other pollutants (all of which are listed in this
report as Great Waters pollutants of concern) and requires that EPA
identify and regulate the sources responsible for at least 90 percent of
total air emissions of each pollutant. Section 112(n)(l)(A) requires EPA
to perform a study of the hazards to public health that are anticipated
to occur as a result of emissions from electric steam-generating units.
A report to Congress on the results of this
study is scheduled to be completed in Novem-
ber 1995. Section 112(n)(l)(B) requires EPA to
conduct a study of the air emissions of mer-
cury from electric utilities, municipal waste
combustors, and other sources, including area
sources. A separate report on the results of
this study is due to Congress by November
1994. Section 112(n)(l)(C) directs the National
Institute of Environmental Health Sciences to
conduct a study to determine a "threshold"
level for human health effects from mercury
exposure, including a threshold for mercury
concentrations in fish that may be eaten by
humans. Because of the strong evidence indi-
cating the importance of atmospheric deposi-
tion of mercury to waterbodies, as well as the
attention given mercury in section 112, this
-------
Chapter One
Introduction
report includes mercury as a "case study" pollutant in each of the three
main scientific sections.
Report Objectives
The main objectives of this Report to Congress are to describe
what is known about atmospheric deposition of toxic chemicals to the
Great Waters and to present'any appropriate regulatory recommenda-
tions based on the currently available scientific information. The report,
along with its supporting documentation, is intended to assemble infor-
mation that will allow EPA to (1) determine the extent to which air
pollution is a significant contributor to water quality problems in the
Great Waters, (2) evaluate the effectiveness of current regulatory
programs in addressing known or potential problems, and (3) decide
whether additional regulatory actions are needed. The report also sum-
marizes progress to date on research initiatives under section 112(m),
identifies critical research needs, and describes the program strategy
that is being developed to address research and regulatory needs. It also
serves as a starting point for EPA's future assessments of the scientific
data available for subsequent biennial reports. This Report to Congress
on the deposition of air pollutants to the Great Waters addresses only
atmospheric deposition of toxic chemicals and nitrogen compounds, and
not acid rain. Atmospheric deposition of nitrogen compounds is
addressed because of nitrogen's role in eutropbication of many coastal
estuarine and marine waters.
This Report to Congress summarizes the
current understanding of atmospheric
deposition of toxic chemicals to the Great
Watgrs and identifies key regulatory and
research needs, based in part on inputs
from leading independent scientists.
Report Preparation
EPA's and NOAA's approach to preparing this report relied
heavily on participation by independent scientists who have conducted
research on atmospheric deposition of toxic pollutants. As a first step,
EPA sponsored a literature search on the topic of atmospheric deposition
of chemicals to surface waters, identifying more than 1,100 scientific
publications.5 EPA then convened three committees of leading indepen-
dent scientists and charged them with evaluating and summarizing the
scientific literature in the three areas identified in section 112(m):
exposure and effects of atmospheric deposition to the Great Waters,
relative atmospheric loadings to the Great Waters, and sources contrib-
uting to atmospheric deposition to the Great Waters. Each committee
prepared a draft paper, and, in November 1992, EPA sponsored a 2-day
workshop to discuss and comment on the draft papers. Attendees of the
workshop included the committee members, other independent scien-
tists, EPA scientists, EPA program representatives, and representatives
of groups that include NOAA, State agencies, and industry and environ-
mental groups. Following the workshop, the committees prepared final
-------
Chapter One
Introduction
documents that represent syntheses of much of the scientific knowledge
in the three areas identified.6'7'8 This Keport to Congress condenses the
information in these three scientific background papers into a relatively
concise and readable report. All scientific data and conclusions pre-
sented in this Report to Congress, except those specifically referenced to
other sources, are drawn from the three background papers, which are
fully referenced.
This document fulfills the section 112(m)(5) requirements for the
first Eeport to Congress on atmospheric deposition to the Great Waters.
Chapter 1 introduces the section 112(m) requirements and the report
objectives, as well as provides examples of studies that identify
atmospheric deposition as a contributor to chemical pollution of the
Great Waters. Chapter 2 summarizes the activities of EPA's Great
Waters Program and highlights the questions it is addressing. Chapter
3 addresses the scientific questions of section 112(m) by summarizing
information on exposure and effects, relative loadings, and sources.
Chapter 4 presents conclusions from an evaluation of the science and
provides regulatory recommendations. All references cited (i.e., the
references for information taken from sources other than the three
scientific background papers) are listed in Chapter 5. The Appendices
include, among other items, a description of past EPA regulations, a
summary of current section 112 activities, a summary of progress to
date on research initiated in response to section 112(m), and a
description of research needs. Future reports to Congress, required
every 2 years, will provide more complete information as it becomes
available.
-------
lt\ t
4 u yotf 4AWUMU
j*t i'
-------
Chapter Two
Overview of the Great Waters Program
Section 112(m) of the Clean Air Act, as amended in 1990
(1990 Amendments), raises numerous questions regarding the extent
and significance of atmospheric deposition of toxic chemicals to the
Great Waters. EPA's Great Waters Program is attempting to answer
these questions. Answers to these scientific questions will provide the
information necessary to determine the need for additional regulatory
actions to reduce atmospheric deposition to the Great Waters.
Scientists have long recognized the basic process by which air
pollutants can enter rivers, lakes, and other waterbodies. The steps in
this process are shown in Figure 2.
• First, pollutants are released to the air from a source, which
may be natural or anthropogenic (i.e., created by humans).
Anthropogenic sources include point sources, such as industrial
smokestacks or any other fixed location that releases pollut-
ants, and area sources, such as pesticide applications on agri-
cultural fields and vehicle exhaust. Natural sources also can
be classified as either point or area sources and include, for
example, forest fires, volcanic eruptions, windblown dust and
soil, and sea spray. Pollutants can be released either as gases
or as particles.
• Second, pollutants released to the ah- are transported away
from their source to other locations. Depending on weather
conditions and the chemical and physical properties of the
pollutant, air pollutants may be transported either short or
long distances from their sources and may undergo physical
and chemical changes while in transit.
• Third, air pollutants are deposited to the earth, in most cases
directly to a waterbody or to a land area that drains into a
waterbody. Pollutants are deposited by "wet deposition" or "dry
deposition." In wet deposition, pollutants are removed from
the air by a precipitation event such as rain or snow. Dry
deposition occurs when particles settle out of the air and into
water. Air pollutants can also enter a waterbody indirectly, by
first depositing onto surrounding land or tributaries and then
moving into the waterbody by other routes, such as stormwater
runoff or inflow from tributary streams.
11
-------
Chapter Two
Overview of the Great Waters Program
.£••'(•?•'••?'•'
Particulate
Matter
Sources of Ibxic Pollutants
Anthropogenic Sources
Natural Sources
Local or long-distance
transport
Changes in chemical/
physical forms Indirect
Deposition*
Wet
Deposition
Dry -''/ 'I1''; /''' Air/Water
Particle , ', • '// Gas
Deposition Exchange
Figure 2. How does atmospheric
deposition occur?
* Indirect deposition is direct depo-
sition to land followed by runoff
or seepage through groundwater
to a surface waterbody.
Current understanding of the details of each of these steps is
limited, although it is growing as a result of recent scientific research
(see Figure 3). As early as 1907, localized atmospheric deposition of
metals around smelters was reported.10'11 In the late 1960s, the discov-
ery of anthropogenic chemicals (i.e., chemicals created by humans) in
Antarctic snow provided strong evidence that air pollutants can travel
long distances and be deposited in remote areas. Additional confirmation
of toxic chemical contamination caused by atmospheric deposition was
provided in the 1970s by, among other studies, the reporting of
anthropogenic chemical contamination in Arctic mammals and the dis-
covery of PCBs and toxaphene in fish in the isolated waters of Siskiwit
Lake on an island in Lake Superior. Studies of atmospheric deposition
continued throughout the 1980s and included mass balance studies of
PCBs and other toxic chemicals in the Great Lakes, implicating air
pollution as a major contributor to contamination of waterbodies. These
studies have yielded considerable information about how atmospheric
deposition occurs and the role and significance of air pollution in influ-
encing water quality.
As part of the Great Waters Program, four major activities have
been identified that will increase the current understanding of atmos-
pheric deposition. Each of these activities addresses different scientific
and regulatory questions, as shown in Table 1. These activities provide a
logical framework for deciding what actions are needed to reduce atmos-
pheric deposition to the Great Waters, thereby minimizing the effects
caused by the deposited pollutants.
12
-------
Chapter Two
Overview of the Great Waters Program
The United States and
Canada, through joint efforts of
EPA, Environment Canada, and
Ontario's Ministry of Environ-
ment and Energy, have been
implementing a bilateral program
on airborne toxic substances in
the Great Lakes basin since 1990.
This program includes bilateral
cooperation in monitoring of toxic
air deposition as part of the Great
Lakes Water Quality Agreement
(GLWQA) Integrated Atmospheric
Deposition Network and in
managing and assessing loadings
of toxic air pollutants to the
Great Lakes Basin.
Many Federal, State, and local government agencies, government
agencies of other countries, and other organizations and independent
researchers are involved in efforts to address the scientific questions
related to atmospheric deposition to the Great Waters. Some of the
groups involved are:
U.S. EPA Offices (including the Office of Eesearch and Develop-
ment, EPA Program Offices, and EPA Regional Offices)
U.S. National Oceanic and Atmospheric Administration
Agency for Toxic Substances and Disease Registry
Environment Canada
International Joint Commission
Great Lakes Commission
Chesapeake Bay Research Consortium
Vermont Monitoring Cooperative
State agencies
Local government agencies.
The four major activities listed in Table 1 are discussed in
sequence below.
Atmospheric deposition identified
as important source of trace
metals in Lake Michigan*
Longest ongoing
precipitation monitoring
for trace metals initiated
at Lewes, Delaware
Contamination of Arctic
mammals with PCBs
reported
Studies indicate 25-40%
of nitrogen loadings to
Chesapeake Bay are from
atmospheric deposition
Clean Air Act
amendments
g i
•)
H
k *— *
i— i
f^^~S Contamination of
^^% Antarctic snow
°°o0o°0 with DDT
°0 ° ,° reported
^ g
O3
T— i
PCBs and toxaphen
discovered in fish
from Siskiwit Lake
published indicating
significance of atmospheric
deposition as source
of toxic chemicals in
Great Lakes
Figure 3. Significant milestones in understanding
atmospheric deposition of toxic air pollutants
to aquatic ecosystems.
* Reference 9, all other information from References 6-8.
• Analysis of pollutant exposure
and effects in the Great Waters.
EPA, in cooperation with other Fed-
eral, State, and local agencies, has
identified, and will continue to iden-
tify, air pollutants that are of pos-
sible concern for atmospheric deposi-
tion based on how long they persist
in the environment, their ability to
travel long distances when released
from sources, their tendency to accu-
mulate in animals and plants, and
other factors. At the same time, EPA
is evaluating whether these pollut-
ants are associated with exposures to
humans, animals, and plants and,
subsequently, with human health
and environmental effects. This first
activity focuses on whether the pol-
lutants of concern for atmospheric
deposition can be linked to any envi-
ronmental or public health impacts
that appear to be significant enough
to warrant action.
13
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Chapter Two
Overview of the Great Waters Program
Analysis of how pollutants of concern actually get
into the Great Waters. EPA and others are evaluating
how much of the toxic chemical pollution in the Great
Waters comes from direct atmospheric deposition and how
much comes from other routes, such as direct discharge,
groundwater seepage, stormwater runoff, and inflow from
connecting streams and rivers (these routes may also carry
pollutants that are from indirect atmospheric deposition). If
it is established that atmospheric deposition adds signifi-
cantly to pollutant loadings of specific chemicals to the Great
Waters (and therefore to the associated impacts identified in
the first activity), actions to reduce atmospheric deposition of
these chemicals may be warranted.
Identification and evaluation of air pollution sources
that are contributing to pollutant loadings to the
Great Waters and that could be targeted if reductions
are needed. EPA and NOAA are working to identify
sources that emit pollutants of possible concern into the air
and are determining which sources appear to add signifi-
cantly to the deposition of air pollutants to the Great
Waters.
Table 1. Major Activities and Questions Addressed by the Great Waters Program
Scientific Questions
1 What do we know about atmospheric
deposition to the Great Waters?
What human health and environmental
effects are associated with pollutants
of concern in the Great Waters?
What is the relative importance of
atmospheric deposition in causing
contamination in the Great Waters?
Where and what are sources of air
emissions of pollutants of concern?
What sources are significant contributors
to the Great Waters?
Would emission reductions be effective
in reducing effects of atmospheric
deposition to the Great Waters?
Regulatory Questions
What action is needed to reduce atmos-
pheric deposition to the Great Waters?
Are impacts or risks significant
enough to be of concern?
Are loadings from the air significant
enough to need reduction?
If reductions are needed, what
emissions sources should be targeted?
What are the options for
implementing reductions?
What are the costs and benefits
of the various options?
Major Activities /
Analyze pollutant exposure and
effects in waterbodies
Evaluate pollutant loadings
to waterbodies
Identify and evaluate air emission
sources
Identify and evaluate emission
reduction options
14
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Chapter Two
Overview of the Great Waters Program
• Determination, based on the information developed
from the three preceding activities, of whether further
emission reductions, beyond those expected as a result
of implementing section 112 of the 1990 Amendments,
may be needed. EPA will identify and evaluate any needed
emission reduction options and, as appropriate, will make
recommendations for regulatory action under the Clean Air
Act or other Federal laws.
Chapter 3 of this report presents the information obtained, to
date, for each of the first three activities, including information on
pollutant exposures and effects, relative loadings, and sources. Much is
known as a result of research conducted to date, as evidenced by this
report. EPA will continue to analyze data as they become available.
Future reports to Congress will update the information presented in
this report, with greater detail and more certainty as research provides
additional data on the subject of atmospheric deposition of pollutants to
the Great Waters.
15
-------
W";'.
4MMMMW
-------
Chapter Three
Answering the Scientific Questions
of Section 112 (m)
What is known about the extent and significance of atmospheric
deposition to the Great Waters? To answer this central question and to
address the issues raised in section 112(m) of the Clean Air Act, as
amended in 1990 (1990 Amendments), this chapter considers three
scientific questions (see sidebar next page). The first section addresses
the question of exposure and effects to evaluate the human health and
environmental effects associated with exposure to pollutants in the
Great Waters. This section identifies pollutants of concern, describes
pathways by which humans, animals, and plants may be exposed to
these Great Waters pollutants, summarizes information on pollutant
levels in the Great Waters and related adverse effects, and presents
several case studies. The second section addresses the question of rela-
tive loading to evaluate how much of the pollution in the Great Waters
comes from atmospheric deposition. This section summarizes the cur-
rent understanding of atmospheric deposition processes and presents
the results of mass balance case studies for selected chemicals and
waterbodies. The third section addresses the question of sources to
evaluate the origins of the toxic air pollutants being deposited to the
Great Waters. This section summarizes what is known about various
sources that emit pollutants of concern and provides several case
studies as examples.
In each of these three areas, it is difficult to establish, in a rigor-
ous scientific manner, definitive cause and effect relationships. In other
words, it is very unlikely that one will find evidence proving that
atmospheric deposition of a specific pollutant from a specific source
caused a specific effect in a specific waterbody. In fact, a major chal-
lenge is proving cause and effect for any one of these links, much less
for the entire chain of events. Reasons for this difficulty include:
(1) the very large number of factors that could contribute to causing an
observed effect and the challenges of determining the contribution of
each; (2) the inability to conduct fully controlled experiments in real-
world field situations; (3) the inability to apply the findings of controlled
laboratory experiments, with full confidence, to real-world conditions;
and (4) the logistical difficulty, time, and expense required to collect the
kinds of data needed to identify cause and effect relationships. Scien-
tists do, however, employ a number of approaches to investigate cause
and effect relationships. These approaches include: (1) establishing
correlations and associations among factors, (2) evaluating trends in
field data over long time periods, (3) analyzing for consistency between
field observations and controlled laboratory data, and (4) confirming
17
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
preliminary findings in different settings by different investigators.
Using these and other tools, scientists frequently can accumulate enough
information to determine the likely causes of a given effect.
Scientific Questions
• Effects
What human health and envi-
ronmental effects are asso-
ciated with pollutants of con-
cern in the Great Waters?
• Relative Loading
What is the relative impor-
tance of atmospheric deposi-
tion in causing contamination
in the Great Waters?
• Sources
What sources are significant
contributors to atmospheric
loadings to the Great Waters?
Regulatory Question
• Regulatory
Is action warranted to reduce
atmospheric deposition?
Effects: What Human Health and Environmental Effects
Are Associated with Exposure to Great Waters Pollutants
of Concern?
In assessing exposure and effects, consideration must be given to
both human health and environmental effects (and the exposures that
cause both types of effects). Both types of effects are important in their
own right, and, in many cases, ecological effects are early indicators of
human health effects. For example, pollutants in water that accumulate
in the tissues of fish may result in direct effects in fish-eating birds, such
as decreased populations. These ecological effects, in turn, may be indica-
tors of potential human health effects related to the consumption of
contaminated fish. In a widely circulated 1990 report, Reducing Risk:
Setting Priorities and Strategies for Environmental Protection, EPA's
Science Advisory Board strongly emphasized the very close link between
human health and ecological health and pointed out that "most human
activities that pose significant ecological risks . . . pose direct or indirect
human health risks as well."12
The mandates of section 112(m) of the 1990 Amendments require
EPA to assess the environmental and public health effects caused by
water pollution attributable to atmospheric deposition to the Great
Waters and to determine whether pollutant loadings to the Great Waters
cause or contribute to exceedances of drinking water or water quality
standards (including, for the Great Lakes, violations of the specific objec-
tives of the Great Lakes Water Quality Agreement). Although a large
number of pollutants are potentially of concern for atmospheric deposi-
tion, this report focuses on only 15 pollutants. Table 2 lists the 15 pollut-
ants addressed in this report, along with examples of their uses (and use
restrictions) in the United States. Thirteen of these pollutants are on the
1990 Amendments list of air pollutants; dieldrin and nitrogen are not on
the list. All 15 are known air pollutants in the vicinity of at least some of
the Great Waters, and all are known to be present in atmospheric depo-
sition (e.g., rainfall). Data indicate that they are present in the Great
Waters and that atmospheric deposition is a pathway by which they
reach the waterbodies. All of the pollutants, with the exception of nitro-
gen, are of concern because of their persistence in the environment
(length of time a pollutant remains in the environment), potential to
bioaccumulate (potential to accumulate in living organisms), and toxicity
to humans and the environment. The range of potential effects asso-
ciated with exposure to these pollutants (except for nitrogen) includes
cancer, effects to the reproductive system, developmental effects (i.e.,
effects on the developing human, including effects on embryos, fetuses,
18
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 2. Selected Pollutants of Concern in the Great Waters3
Pollutant
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
a-Hexaehlorocyclohexane
(a-HCH)
Lindane
(y-Hexachloroeyclohexane)
(y-HCH)
Lead and compounds
Mercury and compounds
Polychlorinated biphenyls
(PCBs)
Polycyclic organic matter
(POM)0
2,3,7,8-Tetrachlorodibenzofuran
(2,3,7,8-TCDF)
2,3,7,8-Tetrachlorodibenzo-p-
dioxin (2,3,7,8-TCDD)
Toxaphene
Nitrogen compounds
Examples of Usesb
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 opera-
tions.
Insecticide used widely in the 1970s and 1980s. All U.S. uses except termite control canceled in
1978; use for termite control voluntarily suspended in 1988. Use of existing stocks permitted.
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. Byproduct of chlorinated compound and pesticide
manufacturing. Also a byproduct 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 used widely
in other countries.
Main component of lindane, an insecticide used on food crops and forests, and to control lice
and scabies in livestock and humans. Currently used primarily in China, India, and Mexico.
U.S. production stopped in 1977. Use was restricted in 1983; however, many uses are still
registered, but are expected to be voluntarily canceled 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 1971. U.S. restrictions on use in
gasoline additives began in 1973 and have continued through the present, with a major use
reduction in the mid-1980s.
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 paint additive in U.S., for interior paint (1990)
and for exterior paint (1991).
Industrial chemicals used widely in the U.S. from 1929 until 1978 for many purposes, such as
coolants and lubricants and in electrical equipment (e.g., transformers and capacitors). In the
U.S., manufacture stopped in 1977 and uses were significantly restricted in 1979. Still used for
some purposes because of stability and heat resistance, and still present in certain electrical
equipment used throughout U.S.
Naturally occurring substances that are byproducts of the incomplete combustion of fossil
fuels and plant and animal biomass (e.g., forest fires). Also, byproducts from steel and coke
production and waste incineration.
Byproduct of combustion of organic material containing chlorine and of chlorine bleaching in
pulp and paper manufacturing. Also a contaminant in some pesticides.
Byproduct of combustion of organic material containing chlorine and of chlorine bleaching in
pulp and paper manufacturing. 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 canceled in 1987.
Byproducts of combustion processes and motor vehicles. Also, compounds used in fertilizers.
"Data for this table are taken from References 13 through 27.
Applicable restrictions (including bans) on use or manufacture in the United States also are described.
TOM is a large class of chemicals consisting of organic compounds having multiple benzene rings and a boiling point greater than
100 CC. Polycyclic aromatic hydrocarbons (PAHs) are a chemical class that is a subset of POM.
19
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Chapter Three
Answering the Scientific Questions of Section 112(m)
and children), neurological effects (i.e., effects on the brain and nervous
system), effects on the endocrine system (i.e., effects on hormone
production and function), and other noncancer effects (e.g., liver or
kidney damage). The potential for effects will depend on the level and
duration of exposure and the sensitivity of the exposed organism.
Furthermore, although some differences exist, the pollutants in
Table 2 overlap substantially with several sets of Great Lakes chemicals
of concern selected by other scientific and regulatory groups, and they
also are generally consistent with the toxic air pollutants that ranked
the highest in a 1991 EPA study to identify priority chemicals for the
Great Waters Program.28 In addition, all of the pollutants in Table 2,
except 2,3,7,8-TCDF and nitrogen compounds, are included on the list of
pollutants that are the initial focus of the EPA/State Great Lakes Water
Quality Initiative, and 10 of the 15 Great Waters pollutants of concern
are designated as chemicals of concern that have the potential to
bioaccumulate (the highest priority group).29
These pollutants, excluding nitrogen, are also of concern based on
the priorities set by the Great Lakes Water Quality Board (GLWQB) of
the International Joint Commission, which is an advisory committee
comprised of representatives from the United States and Canada. In
addition, 5 of the 15 pollutants (cadmium, benzoMpyrene [indicator for
polycyclic organic matter (POM)], lead, mercury, and PCBs) are on the
Chesapeake Bay Toxics of Concern List, and two (dieldrin and toxa-
phene) are on the list of potential substances to be added to the Chesa-
peake Bay list.
Nitrogen compounds were added to the list of pollutants consid-
ered in this report because of nitrogen's role in nutrient enrichment in
coastal waters and because data indicate that atmospheric loadings of
nitrogen to Chesapeake Bay are significant. Accelerated eutrophication,
which results from excessive loadings of nitrogen, can cause ecological
effects such as reduced fish and shellfish populations.
The first 14 pollutants in Table 2 represent air pollutants of prior-
ity concern for the Great Lakes. Because of the potential for these 14
pollutants to cause harm in the Great Lakes, it is likely that they have
the potential to cause harm in other fresh water systems as a result of
their tendency to bioaccumulate in living organisms, to persist in the
environment, and to be toxic to humans and ecosystems. However, the
pollutants listed in Table 2 are not inclusive of all chemicals that may,
now or in the future, be an important component of atmospheric deposi-
tion to the Great Lakes or other Great Waters.
Other pollutants are of potential concern for the effects that they
may cause after being deposited to the Great Waters. In the proposed
Water Quality Guidance for the Great Lakes Systems, 28 "bioaccmnu-
lative chemicals of concern" (BCCs), many of which are air pollutants,
are identified. A BCC is defined as "any chemical which, upon entering
the surface waters, by itself or as its toxic transformation product,
bioaccumulates in aquatic organisms by a human health
20
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Dissolved in water column
(generally available to plants
and animals)
Accumulated in Attached to dissolved organic
living organisms carbon (generally available j^ /
to animals) *&
Attached to particles, settle to bottom (generally
available to bottom feeders and subject to
resuspension by turbulence or dredging)
"f'fif ~" **"* •" r
.«fc f"^
Figure 4. Distribution of pollutants
within a waterbody.
bioaccumulation factor greater than 1000, after considering metabo-
lism and other physicochemical properties that might enhance or
inhibit bioaccumulation, . . . "29 The guidance proposes that addi-
tional controls be established for these BCCs to obtain reductions in
loadings and to ensure that new problems do not develop in the future
with pollutants in the Great Lakes ecosystem that show a propensity to
bioaccumulate and to persist in the environment.29 Ten of the fifteen
Great Waters pollutants of concern appear on this list, and one other
appears on the list of potential bioaccumulative chemicals. These two
lists are provided in Appendix A. Future reports to Congress on atmos-
pheric deposition to the Great Waters may include many of these
additional chemicals.
The remainder of this section describes exposure and associated
effects for the selected pollutants of concern. Exposure can be thought
of as the contact between a chemical and a living organism. Because
atmospheric deposition is a significant source of pollutants for some
Great Waters, it is reasonable to hypothesize that atmospheric deposi-
tion is contributing, to some extent, to exposure and effects occurring in
the Great Waters. Moreover, some studies have found correlations
between atmospheric deposition of pollutants and subsequent exposure
and effects in the Great Waters. Few studies, however, have directly
and strongly linked atmospheric deposition of pollutants to exposure
and, subsequently, to effects observed in the Great Waters. Because of
the data limitations and the overall difficulty in documenting cause and
effect relationships, this section generally does not attempt to attribute
specific effects to atmospheric deposition. Instead, it describes effects of
selected pollutants of concern known to be present in atmospheric depo-
sition. This section is further limited in its scope because much of the
available information is from the Great Lakes and Chesapeake Bay,
since relatively little research has been devoted to other Great Waters.
Current Understanding of Exposure
Figure 4 illustrates, in a simplified form,
the distribution of pollutants in a waterbody.
Once in a waterbody, pollutants will bind to the
surface of particles or dissolved organic material,
concentrate at the surface of the water, or dis-
solve and remain in solution. Most of the selected
pollutants of concern tend to bind to small par-
ticles suspended in water. Over time, pollutants
associated with particles tend to deposit to, and
accumulate in, sediments. In some cases, pollut-
ants in the sediments may not be available for
chemical degradation in the water. However,
contaminated sediments can serve as a major
reservoir of pollutants that continually recycles
Surface microlayer
(concentrated levels,
. generally available .to
plants and animals)
21
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Humans
Cormorant
Smelt
Plankton
Bacteria
and Fungi
Dead Plants
and Animals
Figure 5. Simplified overview of a
food web in the Great Lakes.
the pollutants back into the ecosystem. Pollutants thus are available for
uptake by bottom-dwelling organisms and bottom-feeding fish. Binding
to dissolved organic material may also affect the pollutants' availability
for uptake. Many pollutants tend to concentrate in the surface
microlayer, which is the uppermost layer of water surface (approxi-
mately 50 H-m in depth). The surface microlayer is enriched with nutri-
ents and is an important feeding area for many microscopic plants and
animals. It also is the site for the transfer of chemicals between air and
water. Pollutants dissolved in the water tend to be readily available for
uptake by plants and animals. The uptake of dissolved pollutants may
be the most important means by which many plants and animals are
exposed.
For animals and plants, the possible exposure routes for toxic
pollutants present in waterbodies are intake of food, intake of drinking
water, and diredrcontact with the water. For fish-eating birds and
mammals, intake of food is the main exposure route of concern for
pollutants that are persistent in the environment and that have the
tendency to bioaccumulate.
Bioaccumulation is the uptake and retention of a chemical by a
living organism as a result of either intake of food, intake of drinking
water, direct contact, or intake of air. Biomagnification refers to the
phenomenon in which chemicals become more concentrated in animals
at higher levels in the food web. The selected pollutants for this report
tend to accumulate in fatty tissue, and, as a result of food web interac-
tions, the highest pollutant concentrations are found in animals at the
top of the food web. Figure 5 provides a simplified overview of a food
web in the Great Lakes. In this example, organisms near the top of the
food web, such as humans and bald eagles, would tend to have higher
body concentrations of chemicals that biomagnify than organisms lower
in the food web.
The exposure route of most concern for human health is intake of
food. Intake of drinking water is another exposure route; yet, for pollut-
ants with the capacity to bioaccumulate, this is typically not a signifi-
cant exposure route of concern.
Estimates of exposure levels can be made using data on pollutant
concentrations in various parts of the ecosystem. Researchers have
investigated surface water, sediment, and fish tissue concentrations of
toxic chemicals in the Great Lakes and Chesapeake Bay, to determine
the pattern and extent of contamination. In the Great Lakes, they found
that the influence of anthropogenic sources since the 1940s has resulted
in significant increases in the levels of many persistent toxic chemicals.
However, there were few reliable data on toxic chemical concentrations
in water in the Great Lakes until 1980 or later.30 As a result, it is very
difficult to draw an accurate picture of tune trends in water concentra-
tion data. Recent research, however, has shown that most pollutants of
concern usually are found in water samples at very low levels, although
22
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Chapter Three
Answering the Scientific Questions of Section 112(m)
even at low levels some pollutants may cause significant effects in plants
and animals in the Great Waters.
In general, pollutant levels in sediments have decreased, relative
to the 1970s, and the bulk of toxic pollutant influx into the Great Lakes
ecosystem occurred in the 1960s and 1970s.30 However, sediment
concentrations are still particularly elevated in sediment basins, harbors,
and delta regions (near the mouth of the river), indicating that runoff
and industrial discharge may be the source of some pollutants.31
Compared with water concentrations, sediment concentrations of pollut-
ants of concern are considerably higher, reflecting the tendency of these
pollutants to attach to particles and settle to the sediments.30 Sediment
processes such as resuspension and resolubilization can reintroduce
significant pollutant loads.
As described earlier, pollutants in sediments and water can be
transferred to fish and other aquatic animals by direct contact and by
intake of food and water and can be concentrated in the animal by the
process of bioaccumulation. Numerous studies have documented cases of
elevated levels of persistent toxic pollutants in various fish species com-
pared to levels in water and, in many cases, compared also to levels in
sediment, reflecting the tendency of these pollutants to bioaccumulate.
Because many Great Waters bird and mammal species rely on fish
and shellfish as a primary food source, bioaccumulation and biomagni-
fication of these pollutants is a problem for wildlife. In fact, predators
such as the herring gull, bald eagle, and turtle in the Great Lakes
region have some of the highest reported tissue concentrations of persis-
tent toxic chemicals. The measurement of persistent toxic chemicals in
herring gull eggs has been used as an indicator of pollutant levels in the
Great Lakes ecosystem.30 One study suggested that levels of toxic pol-
lutants in herring gull eggs have decreased from the 1970s to the early
1980s.30 Another study shows a general decline in levels of DDE and
PCBs during the early and mid-1980s, with an increase for PCBs in
1989. DDE levels have gradually ebbed, without recent rises.32 Data on
concentration levels in Great Lakes mammals are scarce because most
research has centered on birds.
The presence of the same pollutants in the tissue of humans and
other fish-eating animals as those identified in water, sediment, and fish
indicates that biomagnification through the food web has the potential
to be a significant exposure concern for humans. Studies indicate 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 bodies compared with those who did not consume fish.8
The limited human tissue residue data available indicate that the
general population residing in the Great Lakes basin is probably not
exposed to higher levels of the most persistent pollutants than people
residing elsewhere in North America. However, individuals (e.g., native
peoples, sports anglers) who consume large amounts of contaminated
fish and wildlife have greater exposure to persistent pollutants than the
23
-------
'l JB Si i If"'"} '*j!jf i ' « •" i*j Sf'l! *|Mr<*pi ^mmitimmai^ ^i-^:''!'.-r^i\'if»^f'l','-;ay^V'-:--^'f
he_ ^lejipfic Questions of Section 112(m) ' ... ...'.'.•
Total PCS and DDT Concentrations in Lake
Michigan Lake Trout
100
EPA Fish Tissue
Concentration at 10"5
Risk Level
70 72 74 76 78 80 82 84 86 88 90 92
Year
EPA Fish Tissue
Concentration at 10'5
Risk Level
68 70 72 74 76 78 80 82 84 86 88 90 92
Year
Source: Reference 29.
PCB Concentrations in Coho Salmon
10
Huron
Michigan
Erie
Ontario
Traces in Lake Superior
.#3^'^Wfft5^^a^^;iiH9W?M»^f»j>.'*.'Jv<- FVf.f: -'...'•••, ?.:V;B;V«
Ti^dblnTo!^ .' :
Concentrations in Great Lakes Fish
Concentrations of PCBs and DDT in Lake Michigan lake
trout have declined markedly since the latter half of the 1970s,
reflecting the relatively rapid response of the water column to
decreases in pollutant loadings. Beyond 1982, however, concen-
trations in lake trout have been higher thaii predicted levels.
Although concentrations are still declining, the rate of decline
is slowing and may be leveling off, although at concentrations
well above water quality criteria. •.-...•
These substances appear to be approaching equilibrium
in the Great Lakes system at unacceptably high levels due to
^continuing loadings from a variety of sources, such as: (1) his-
torically contaminated sediments; (2) tributary inputs resulting
from point sources, spills and runoff from both urban and, rural
areas, and resuspension from contaminated sediments; and (3)
atmospheric deposition of pollutants. In 1990, concentrations of
PCBs and chlorinated pesticides measured in fish tissue
exceeded the fish tissue concentrations that correspond to cur-
rent EPA Clean Water Act 304(a) water quality criteria by
several orders of magnitude.* If a new equilibrium is being
reached given current mass loadings, then substantial reduc-
tions to the Great Lakes system will be necessary to eliminate
fish advisories,29
The slowing in the rate of decline of PCBs in fish tissue is also supported
by eoho salmon data. Because coho are stocked and are in the lake for only 18
months, they respond much more quickly to changes in water column coneentra-
n "" lions than lake trout, which have an average life span of 8
years and can, therefore, accumulate greater PCB concentra-
tions. After significant declines between 1980 and 1984, PCB
concentrations in coho salmon have been relatively constant in
all the Great Lakes since the mid-1980s, with the exception of a
general decline in Lake Ontario.
79 80 81 82 83 84 85 86 87 88 89 90 91
Year
*Section 304(a) of the Clean Water Act establishes numeric water
quality criteria for the protection of the health and welfare of
(including, but not limited to) plankton, fisjh., shellfish, wildlife,
"plant life, shorelines, beaches, aesthetics, and recreation, which
may be adversely impacted due to the presence of pollutants.
W^^ s-"."-:i"v... . ,
T^ •..:. ,...••/ ..•>. :.>---v;JI ;::'»•:-
'.'-'1'-* *Ji.iti5«i?nf'!%5*i'-A''- "t'-;-.—'^-:-^' ••''••'.:•.• ^.ru:.-. ••••*.•••'.:. -. ;-:,-;-:-i:"'' •••?£•.• .
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Chapter Three
Answering the Scientific Questions of Section 112(m)
general population.32 Studies of these sensitive subpopulations are
currently being performed by the Agency for Toxic Substances and
Disease Registry of the Department of Health and Human Services.
Given the elevated levels of the selected pollutants of concern in
water, sediments, fish and wildlife, and humans, concern for human
exposure is warranted. One means of limiting human exposure is the
establishment of fishing or fish consump-
tion advisories or restrictions.
A fishing advisory or fish consump-
tion advisory is issued when fish taken
from a particular body of water are found
to contain levels of contaminants that
exceed recommended intake, or threshold,
levels. The majority of the advisories are
recommendations to the general public
about the dangers of fish consumption.
Advisories to regulate commercial fishing
are enforceable by health departments
and are often referred to as "fishing
restrictions." Tables 3 and 4 summarize
current fish consumption advisories and
fishing advisories for some of the Great
Waters. As shown in Table 3, portions of
all of the Great Lakes and many associ-
ated waterbodies have had or do have
some type of advisory on fish consumption. As shown in Table 4, fish
consumption and fishing advisories have also been issued in Chesapeake
Bay and Lake Champlain. The elevated tissue levels in fish relative to
water concentrations, which have resulted in restrictions in fish con-
sumption, emphasize the importance of bioaccumulation, and subse-
quent biomagnification in the food web, when considering potential for
human exposure.
Summary of Current Understanding of Exposure
1. What Are the Major Routes of Exposure to Pollutants Derived
from Atmospheric Deposition?
For water pollutants that are derived from atmospheric deposition,
the major routes of exposure are fairly well understood. For animals,
routes of exposure include intake of food (especially significant
because of biomagnification in the food web), intake of drinking
water, and direct contact. Routes of exposure for plants include water
uptake and direct contact. For humans and for fish-eating mammals
and birds, the primary route of exposure is intake of food.
Although routes of exposure have been identified, the amounts of
toxic pollutants to which humans, animals, and plants are exposed
are not easily determined given the currently available data.
25
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 3. Current Great Lakes Fish Consumption Advisories3
i Water-body
(including
! tributaries)
Lake Superior
Lake Michigan
Green Bay
Lake Huron
Saginaw Bay
Lake Erie
Lake Ontario
St. Mary's River
St. Clair River
Lake St. Clair
Detroit River
Niagara River
St. Lawrence
River
Pollutant
PCBs, chlordane,
and mercury
PCBs, chlordane,
DDT, dieldrin,
and mercury
PCBs and pesticides
PCBs
PCBs and dioxins
PCBs and chlordane
PCBs, dioxins, and
chlordane
Mercury
PCBs and mercury
PCBs and mercury
PCBs and mercury
PCBs and dioxins
PCBs
Restrictions'
Lake trout, chinook salmon, and walleye
Lake trout, coho salmon, chinook salmon,
brown trout, and walleye
Splake
Brown trout, lake trout, and rainbow
trout
Rainbow trout and brown trout
Walleye
Freshwater drum and gizzard shad
Walleye, white bass, smallmouth bass,
white perch, carp, rock bass, largemouth
bass, bluegill, freshwater drum,
carpsucker, catfish, and northern pike
Freshwater drum
Carp and smalhnouth bass
All fish
'•'.'. '• m Not Eat ;.-• • •
Lake trout over 30", walleye over
26", catfish, northern pike, and
white sucker
Lake trout over 23", chinook
salmon over 32", brown trout
over 22", carp, and catfish
Lake trout, brook trout, rainbow
trout, chinook salmon, brown trout,
splake over 16", northern pike,
walleye, white bass, and carp
Brown trout over 21" and rainbow
trout over 21"
Carp and catfish
Carp and catfish
American eel, catfish, lake trout,
chinook salmon, coho salmon,
rainbow trout, brown trout
Carp
Muskie, sturgeon, and catfish
over 22"
Carp
Channel catfish, American eel,
lake trout, chinook salmon,
rainbow trout, coho salmon,
and brown trout
Channel catfish, American eel,
chinook salmon, brown trout,
lake trout, coho salmon over 21",
and rainbow trout over 25"
*Data for this table are taken from Reference 13.
Restrictions: Nursing mothers, pregnant women, women who anticipate bearing children, female children of any age, and male
children age 15 or under should not eat fish taken in these locations. Other persons should limit their consumption to one meal
per week and follow preparation and cooking recommendations.
26
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 4. Current Fishing Advisories in Selected Great Waters*
Waterbody
Chesapeake Bay
(Maryland)
Chesapeake Bay
(District of Columbia)
Lake Champlain
Advisories
Chlordane: Black crappie and carp from Lake Roland; channel
catfish and American eel from Baltimore Harbor and Back River
Chlordane: Potomac River
PCBs: Potomac River
Vermont and New York
PCBs: Lake trout over 25 in.
Mercury: Walleye over 19 in.
Cumberland Bay only
PCBs: American eel, Brown bullhead
aData for this table are taken from References 23 through 39. Includes information for the
selected pollutants of concern only.
2. To What Extent Does Atmospheric Deposition Contribute
to Overall Exposure to Toxic Chemicals in the Great Waters?
Current understanding of the extent to which atmospheric deposition
contributes to overall exposure is limited because overall exposure to
toxic water pollutants has not been fully quantified and because
complete and accurate information on all pollutant inputs and out-
puts is not available. For example, the presence of pesticides, such as
toxaphene, that have never been used extensively in the Great Lakes
region can be attributed primarily to atmospheric deposition. Similarly,
reductions in lead concentrations in fresh water fish have been attrib-
uted to decreases in lead emissions from motor vehicles, suggesting the
importance of atmospheric deposition for exposure.40 On the other
hand, many pollutants such as 2,3,7,8-TCDD are derived from several
sources, and determining how much comes from atmospheric deposition
alone is difficult.
Current Understanding of Effects
Much of the ecological effects information presented in this section is
based on observed effects from field studies in which ecological effects data
were correlated with pollutants present in the environment. This informa-
tion generally is supported by laboratory study data, as detailed in the
technical contractor report.8 Because of the limited observed effects data
for humans and the difficulties in obtaining such data, the human health
effects information presented also refers to data on effects in animals that
are suggestive of potential human health effects.
27
-------
j;^^
| ..... li:-1-"*!!.''-! ..... ; ...... pirtr^'^Ji*^! ..... W-T! ..... iirjit'Sl:*;.?'-1 ;'NJ-4'i'>ii*f;**f;!!:^j"^ii.l|}Ji'.i:J!i-''';i-v ^•X-iV-3;.;'.'/ ,^'-': ..':vi<:.:v£:V.U4C;i;-]rijM;.
"' ' ''
j-^^ 3 M';"';' '•":•'*; . '-??- •?-•'•' Y i;'-.-tIJ'* 'i
Justic
ii^f.^''™**
$K,jiki
iiili ; iia 3
,>;!|1' -.J i '• ,: i-'W" j T'T'"'', - :. ' ;''-•iS?^**^|L*^«•''/^^:sl••:fe"i;^!*H^•••"'^iVV'%•X'•V1"•'•'''•'•.•l ^w''?i;;t:G^V.:, :Y:..''V' '-: -'"•? Vir:V'i»'-•':!'•' •
11 ( j; Jfumgrfjus ^^rly'studies haveexamined ffierelationship between the cons'timp- :
tion offish from the Great Lakes and observable health effects in certain subpopu-
lations. Subpopulations identified as especially vulnerable to exposure to persistent
toxic substances in the Great Lakes include: pregnant and nursing females (who are
more vulnerable to effects), sport anglers, Native Americans, and the urban poor
(who have high fish consumption for reasons of economic need or cultural tradition).41
This makes environmental justice an important issue. v
Examples of study results:
• In 1990, a study entitled "Fish Consumption Patterns and Blood Mercury
Levels in Wisconsin Chippewa Indians" was conducted by the Center for
Disease Control to investigate Wood mercury levels among Wisconsin's
Qjibwa population. Of the 357.acfulfs (from five Ojibwa tribes) tested, 64 were
••"* ''i'l';;l"i' ''•;™"«T-»'^V---' -found to have .blood mercury levels in excess of 5 jig/Li.
Since a report from the Institute of Medicine suggests
that delayed development of infants may occur following
in utero exposure to maternal blood mercury levels of
5 to 10 JJ-g/L, the results of the Wisconsin Chippewa
study warrant concerns for human health.41
• A1989 survey of Michigan sport anglers showed a :.
tendency for fish consumption to increase With age, for
minority ethnic groups to consume more fish than
whites, and for fish consumption to diminish as the
educational level of a household increases.42
• A 1992 survey of 300 Detroit riverbank anglers
showed that 32% of those who ate the fish were children
between the ages of 5 and 18 years, and 26% were
women of childbearing age. Minorities made up 94% of
those fishing the Detroit River within the city limits,
SnfeipQ^.-beipg.Ajrilgap.,Anje,ricaii. Almost 35% of the, .„,„.
tr ^ieT^T^&cated&a0^ey^AiA_'aot feel adequately informed about .&,
isk associated with eating fish from the Detroit River.43
It should be noted that there are concerns related to methodology
that can be raised with respect to many, if. not all, of these studies.
These concerns led the EPA to create a Fish Contamination work
group, which is writing technical guidance designed to improve the
quality of such surveys.42 In addition, the Department of Health and
Human Services, Agency for Toxic Substances and Disease Registry, is
in the process of completing a report summarizing the "Impact on
Public Health of Persistent Toxic Substances in the Great Lakes
Region," with a review of available studies on consumption of contami-
nated fish.41
Although concerns over methodology exist, results of studies
suggest that certain subpopulations will be more likely to consume
later amounts of Great Lakes fish and, therefore, be more exposed to
ic chemicals and their effects. These issues need to be considered in
decisionmaking on toxic substance control.
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
Ecological Effects
Ecological effects associated with pollutants known to be present in
atmospheric deposition are evident in numerous studies describing birth
defects, reproductive failure, disease, and premature death in fish and
wildlife species native to the Great Lakes.8
In general, ecological effects of exposure to toxic pollutants can
occur at both the individual level and the ecosystem level. Effects at the
individual level include both cancer and noncancer effects. There is a
broad spectrum of noncancer effects, including changes in enzyme func-
tioning and effects on the endocrine, immune, nervous, and reproductive
systems. Effects at the ecosystem level may in-
clude changes in populations (e.g., reproduction
rates) and communities (e.g., species diversity).
Another effect, eutrophication, to which atmos-
pheric deposition can contribute, can produce
both individual- and ecosystem-level effects.
Ecological effects associated with pollutants
of concern range from short-term, chemical-
specific effects (e.g., fish disease, wildlife disease,
effects on reproduction) to gradual, cumulative
effects (e.g., population declines, community
changes). Effects on the reproductive system can
have negative impacts both on an individual's
reproductive success and on the ecosystem by
reducing a population's rate of reproduction. In
addition, most pollutants of concern bioaccumu-
late to high levels in fish and fish-eating wildlife.
At these higher exposure levels, fish and wildlife are more likely to suf-
fer various cancer and noncancer effects. The remainder of this section
briefly discusses some of the important effects of the pollutants of
concern on aquatic organisms and other wildlife.
Effects on Aquatic Organisms and Other Wildlife. Several of
the selected pollutants of concern cause changes in enzyme functioning.
Studies have reported that the activity of enzymes responsible for the
breakdown of foreign compounds is greatly increased by most of the
chemicals of concern. In fish, the increased activity of these enzymes has
been shown to result from exposure to PCBs and PAHs (PAHs are a
subset of POM). 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 expo-
sure to environmental pollutants.
Effects on system functioning are reflected in findings of deficien-
cies in the immune system of beluga whales during a long-term study in
the St. Lawrence River (located in the Great Lakes basin). This study
indicated that these populations of beluga whales have significantly
higher tissue concentrations of PCBs, DDT, and other toxic chemicals
29
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
than other marine mammal populations. Researchers attributed the
generally poor health of the St. Lawrence beluga whales to suppressed
immune system activity resulting from exposure to environmental
chemicals. Other studies in the Great Lakes region also have found
associations between PCBs and DDT and decreased immune system
function. In the Chesapeake Bay region, diminished immune response
was demonstrated in bottom-dwelling fish of the Elizabeth River
exposed to sediment contaminated with PAHs.
Particular concern is warranted for humans and other animals
because of the effects these pollutants have on other body systems such
as the nervous system (including behavioral effects) and endocrine sys-
tem. Recent data indicate that effects to these systems may occur at
very low exposure levels. For example, populations of Great Lakes
herring gulls, Forster's terns, and ring-billed gulls have exhibited behav-
ioral changes such as female-female pairings, which result in abnormal
incubation activities and nesting behavior, including nest abandonment.
Exposures to pollutants of concern have resulted in effects on the endo-
crine system such as thyroid disorders, loss of reproductive functions in
certain species, deficiencies in hormones such as insulin, and changes in
reproductive success related to hormone function.
Effects on the overall health of individual aquatic organisms are
reflected in reports of skin and liver cancers in fish and beluga whales.
In some cases, these cancers have been attributed to concentrations of
PAHs. In one study of stranded beluga whales in the St.
Lawrence River, tumors were discovered in 40 percent of the
whales examined. In another study in the Great Lakes, bottom-
feeding fish such as bullhead were found to have increased
tumor occurrence and a broad variety of tumors. These tumors
were linked to exposure to PAHs.
Effects on Great Waters ecosystems are evident in
changes in fish communities present in the Great Lakes and
Chesapeake Bay and population declines in many fish species.
Another indicator of ecosystem effects is the drastic change in
bottom-dwelling communities in the Great Lakes.38 Exposure of
these communities to toxic chemicals has resulted in significant
changes in species diversity and populations.38 In addition,
populations of bottom-dwelling invertebrates have shown higher
frequencies of deformed mouth parts and head capsules.38
Changes in the ecosystem are reflected in other wildlife also.38
Bald eagles, herring gulls, and Forster's terns in the Great
Lakes region have undergone significant population declines
since the 1960s.38 Only in recent years, as concentrations of
water pollutants in the Great Lakes have declined, have some
species (e.g., bald eagles) begun to recover.4
30
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Reproductive Effects. Effects on reproduction include embryo
toxicity, hatching success, abnormalities in offspring, parental behavior
change, and changes in mating. These effects are often accompanied by
higher concentrations of PCBs, DDT, dieldrin, and other chlorinated
compounds in animals. Specific effects noted in various species include
reduced fertility, reduced hatchability, reduced survival of offspring,
impaired hormone activity, changed adult sexual behavior, and sparser
shoreline populations relative to inland populations. Pollutants of con-
cern that have been linked with reproductive impairment
include toxic metals (e.g., cadmium, mercury, and lead),
lindane, PCBs, DDT/DDE, dieldrin, and 2,3,7,8-TCDD.
Usually, observed reproductive effects cannot be
linked conclusively to specific pollutants; however, link-
ages often are made through similarities of effects across
species and geographic locations. For example, eggshell
thinning in a number of bird species and associated repro-
ductive loss are linked to DDT in the 1960s and 1970s,
and decreases in environmental concentrations of DDT
have resulted in population recoveries. However, popula-
tions in certain regions of the Great Lakes still exhibit
reproductive failure. For example, bald eagle populations
near the Great Lakes show much lower reproductive
success than populations inland. Many eggs in shoreline
nests contain lethal concentrations of PCBs, DDE, and dieldrin, result-
ing in bald eagle reproduction rates too low to maintain a population.
In laboratory studies, mink that were fed PCB-contaminated fish
responded with decreased reproduction and lower offspring survival.
PCB levels in the fish used in that study were similar to those found in
some regions of the Great Lakes.
Eutrophication. Eutrophication, which refers to the ability of a
waterbody to produce organic material, is a natural process that takes
place over geologic periods of time, but which can be accelerated by
anthropogenic additions of nutrients (see Figure 6). Eutrophic lakes,
which occur when nutrients such as nitrogen and phosphorus are
present in excess amounts, are characterized by very high productivity
and by high organic content from the decay of plants and recycling of
carbon. In freshwater lakes, concentrations of phosphorus, which has
only minor atmospheric inputs, generally are limited and therefore
control productivity. Atmospheric deposition is not thought to be a major
factor in eutrophication of freshwater lakes.
In coastal waters, nitrogen, which can have significant atmos-
pheric inputs in the form of various nitrogen compounds, generally is
the nutrient that controls eutrophication.
31
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Natural Eutrophication
Man-induced Eutrophication
I
,
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 5. Potential Human Health Effects* Associated with Pollutants of Concern1"
Pollutant*
Cadmium
and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachloro-
benzene
a-HCH1
Lindane
Lead and
compounds
Mercury
and compounds
PCBs
Polycyclic
organic matter
2,3,7,8-TCDF
2,3,7,8-TCDD
Toxaphene
Potential Effects on Human Health0
Cancer6
Probable11
Probableh
Probable11
Probable11
Probable11
Probable11
Probable'
Probable11
Probable11
Probable11
Not classifiable11
Probable3
Probable11
Reproductive/
. Restrictions*
•
•
•
•
•
•
(y-HCH)
•k
•
•
•
•
•
•
Neurological/
Behavioral
•
•
•
•
•h
•
•k
•
•
•' .
•
Immuno-
logical
•
•
' •
•
«
•
•
•
•
•
•
•
•
Endocrine
•
•
•
•
•
•
•
•
•
Other
Noncancerg
Respiratory and
kidney toxicity
Liver toxicity11
Liver toxicity11
Liver toxicity11
Liver toxicityh
Kidney and liver
toxicity
Kidney and liver
• toxicity11
Kidney toxicityk
Kidney toxicity
Liver toxicity
Blood cell
toxicity
Liver toxicity
Integument
toxicity1
Cardiovascular
effects; liver
toxicityf
aThese data are based on a compilation of results from both human and animal studies. Potential for effects will depend on the level
and duration of exposure and the sensitivity of the exposed organism.
bWhere footnoted, data for this table are taken both from EPA sources 48'54 and the applicable Agency for Toxic Substances Disease
Registry (ATSDR) Toxicological Profile 14-22'24-26-55; otherwise, all data are taken from the applicable ATSDR lexicological
Profile alone.
°For this table, a chemical 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).
dNitrogen compounds are not included in this table because they are considered a pollutant of concern only for eutrophication.
e A chemical is classified as a "probable human carcinogen" when there is limited or no evidence of human carcinogenicity from
epidemiologic studies but sufficient evidence of carcinogenicity in animals (corresponds to EPA weight-of-evidence category B).
A chemical is classified as "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).
f Data from the applicable EPA Health Effects Assessment (HEA) document.60-53
gThis is 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.
hData from EPA's Integrated Risk Information System.49
1 Toxicity data are available primarily for y-HCH and technical-HCH (a mixture of several HCH isomers), with limited data available
for a-HCH.
J Data from EPA's Health Effects Assessment Summary Tables (HEAST).48 HEAST classifies these chemicals as probable human
carcinogens; however, these carcinogenic evaluations are currently under review by EPA.
kData from EPA's Reportable Quantity (RQ) Document for lead.54
1 Data from Biological Basis for Risk Assessment ofDioxins and Related Compounds.56
33
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Chapter Three
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In general, few of these chemicals are acute toxicants or genetic toxi-
cants at concentrations found in the Great Waters; however, several are
developmental toxicants that, through low-level exposures to parents,
are capable of altering the formation and function of critical physiologi-
cal systems and organs in children.
Two studies in the United States looked at infants and children
who were nonoccupationally exposed to PCBs during prenatal develop-
ment. Both studies found nervous system deficits. One study showed
that children of mothers who ate PCB-contaminated fish (on average
2 to 3 meals per month of lake trout or salmon) from Lake Michigan
before 1980 (when PCB concentrations in fish were higher than at
present) exhibited deficits in cognitive function.8 In another study,
children in North Carolina showed motor abnormalities at birth and
psychomotor delay at up to 2 years of age.8 Both studies have generated
controversy, mainly over study design, data analysis, selection of,
appropriate statistical tests, and even whether psychological tests are
appropriate instruments in population studies.46
In a followup to the Lake Michigan study, the same children were
evaluated at 4 years of age. These children were found to have subtle
deficits in short-term memory and speed of information processing,
which could impact the child's ability to master basic reading and
arithmetic skills in school. An 11-year followup study on these children
has begun.47
Summary of Current Understanding of Effects
1. What Are the Major Effects Associated with Pollutants
of Concern for Atmospheric Deposition?
The potential human health and environmental effects associated
with the selected pollutants of concern are generally well documented.
In humans, the potential effects include cancer, reproductive and
developmental effects, neurological effects, endocrine and immune
system effects, and organ system toxicity. All of the pollutants of
concern (except nitrogen compounds) are known to bioaccumulate in
animals, including humans. In animals and plants, the potential
effects of individual pollutants are not always well denned; however,
linkages have been made between exposure to pollutants of concern
and observed fish and bird deaths, reproductive effects, deformities in
wildlife, and population declines. In the environment, it is difficult to
relate a specific effect of concern (e.g., reproductive effects) to a single
pollutant, because most affected animals have elevated body concen-
trations of many pollutants. It is known, however, that exposure to
pollutants of concern can result in serious ecological and human
health effects, particularly when animals are exposed to the pollutant
through intake of food.
34
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Chapter Three
Answering the Scientific Questions of Section 112(m)
In addition, it is well established that nitrogen is usually the limiting
nutrient controlling eutrophication in coastal waterbodies and that
eutrophication in these systems can cause severe system-wide ecologi-
cal effects.
2. What Is the Contribution of Atmospheric Deposition
to Adverse Human Health and Environmental Effects?
The relationship between adverse effects of toxic pollutants and
atmospheric deposition is not well understood. Some correlations and
linkages between specific pollutants of concern and effects in the
Great Waters can be established. Yet, at this time, quantifying the
contribution of atmospheric deposition of each pollutant of concern to
ecological and human health effects is not possible. For example, a
pollutant may produce reproductive effects at a given concentration
under certain exposure conditions, but the pollutant present in a
waterbody generally is derived from many sources, and the link
between an observed reproductive effect and atmospheric deposition
is very difficult to determine.
Comparisons with Water Quality Benchmarks
As one means of assessing the significance of contamination of the
Great Waters caused by the selected pollutants of concern, available
water sampling data can be compared with various water quality crite-
ria. Such comparisons are consistent with requirements in section
112(m) of the 1990 Amendments for EPA to assess the contribution
of atmospheric deposition to exceedances of certain water quality stan-
dards and criteria. This section first describes several sets of relevant
water qualify benchmarks—EPA's national ambient water quality crite-
ria (AWQQ), EPA's recently proposed Great Lakes water quality criteria
(pGLWQC), and the U.S.-Canadian Great Lakes water quality objectives
(GLWQOs)—and then summarizes how the available Great Waters
sampling data compare with the criteria. Because of limited sampling
information for many of the selected pollutants of concern in Great Wa-
ters other than the Great Lakes, this summary focuses primarily on the
Great Lakes.
This section compares water sampling data with water quality
benchmarks, rather than comparing sediment contamination data or
biological contamination data to appropriate benchmarks, for two main
reasons: (1) the specific emphasis of section 112(m) requirements on
water quality standards and benchmarks, and (2) the limited availabil-
ity of Federal or other widely accepted numerical benchmarks for sedi-
ments or living organisms for the selected pollutants of concern. How-
ever, because of the strong tendency of most of the selected pollutants of
concern to bind to sediments and to bioaccumulate, comparisons of sedi-
ment and biological contamination levels to appropriate benchmarks,
where such benchmarks are available, has advantages over comparisons
35
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Chapter Three
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based on water contamination levels. First, for most of the pollutants,
sediment and biological contamination levels generally are much higher,
and therefore easier to measure, than water contamination levels. Simi-
larly, the levels of concern (i.e., the benchmarks) for these pollutants are
generally much lower for water than for sediments or for
living organisms, resulting in the need to be able to measure
very low water concentrations to ensure that criteria or stan-
dards are not being exceeded. For example, the newly pro-
posed Great Lakes water quality criterion for 2,3,7,8-TCDD is
9.6 x 10"6 parts per trillion (9.6 x 10"12 milligrams per liter),
an extremely low level. Second, sediment and biological con-
tamination levels better reflect the overall pollutant loading
over time in a waterbody because of the tendency of the se-
lected pollutants of concern to accumulate in sediments and
in living organisms. Therefore, the absence of water quality
benchmark exceedances for pollutants that have a strong
tendency to bind to sediments and to bioaccumulate does not
necessarily indicate the absence of contamination at levels of
potential human health or ecological concern.
Maximum contaminant levels (MCLs) are "maximum
permissible level[s] of a contaminant in water which is [are]
delivered to any user of a public water system."57 These
levels are developed under the Safe Drinking Water Act, and
the goal in developing MCLs is to approach as closely as
possible ideal human health-based levels while still taking
into account the cost of achieving the levels as well as the
availability of technology to achieve them. At this time, some
chemicals do not have MCLs. Few violations of existing levels
have been found in Great Lakes drinking water systems,
and, for the pollutants that do exceed their MCL, the distri-
bution system rather than the water source may be the
principal cause.31
AWQC are designed to protect humans and freshwater
and saltwater animals and plants from harmful effects resulting from
both chronic and acute exposures.58 The development of AWQC is an
ongoing process that is meant to reflect current knowledge on health
and welfare effects, dispersal of pollutants across media, and effects on
animal and plant communities and on reproduction. Several different
AWQC values may be published for an individual chemical, including
values designed to protect freshwater aquatic organisms (for both acute
and chronic exposure), marine aquatic organisms (for both acute and
chronic exposure), and humans (for chronic exposure through consump-
tion of both fish and drinking water and for chronic exposure through
fish consumption only). EPA's national AWQC, which are based entirely
on scientific data, are provided as guidelines and are not directly
applicable as enforceable water quality standards. Rather, AWQC are
intended to be used by States as a basis for developing regulations.
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Applicable national AWQC are available for all of the selected pollut-
ants of concern except 2,3,7,8-TCDF and nitrogen compounds.
In April 1993, EPA proposed and requested public comment on
new water quality criteria specifically for the waters in the Great Lakes
system.29 When the criteria are made final, they will form the basis for
new water quality standards to be issued by States in the Great Lakes
basin. Criteria are proposed 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). The proposed
methods for deriving these criteria differ in some respects from the
methods used for deriving national AWQC, and, in general, the proposed
Great Lakes criteria are lower to account for bioaccumulation.
The Great Lakes Water Quality Agreement of 1978 is an agree-
ment between the United States and Canada that adopted the principle
of "virtual elimination" of persistent toxic substances to the Great Lakes
(i.e., a goal of zero discharge).59 For a number of chemicals, the
Agreement includes specific GLWQOs that are set to protect the most
sensitive user of the water among humans, aquatic life, and wildlife. For
other persistent toxic chemicals, such as hexachlorobenzene, no specific
GLWQO has been established; for such chemicals, concentrations in
water and in aquatic organisms should be lower than detection levels.
Specific GLWQOs are available for 8 of the 15 selected pollutants of
concern, and recommended values are available for four additional ones.
The table in Appendix B shows which of the selected pollutants of
concern have potentially exceeded national AWQC, pGLWQC, and
GLWQOs, based on Great Lakes sampling data since 1980. The table
provides comparisons of maximum open water (i.e., away from shore
and not as strongly influenced by direct discharge) concentrations of the
pollutants with their respective water quality benchmarks. In interpret-
ing these results, it is important to remember that the sampling data
used in the comparisons are maximum values (generally based on a
total of 10 to 30 samples) and are not necessarily representative of
ambient water concentrations throughout the lake. Dieldrin, mercury,
and PCBs exceeded criteria in all five Great Lakes, while DDT/DDE
exceeded criteria in all but Lake Superior (mercury and PCBs almost
always exceeded more than one of the applicable criteria). In addition,
hexachlorobenzene exceeded criteria in Lakes Erie and Ontario, and
cadmium exceeded criteria in Lake Erie. Thus, open water concentra-
tions of several pollutants of concern in the Great Lakes—which are
expected to be substantially lower than maximum near-shore concentra-
tions—have potentially exceeded applicable water quality criteria at
some locations in the recent past. Moreover, maximum concentrations
of most of the other selected pollutants (i.e., those that did not exceed
criteria) in most of the lakes were within a factor of 10 of the lowest
applicable criterion, indicating contamination that approaches levels
of concern.
37
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Sampling data for the selected pollutants of concern in Lake
Champlain are considerably more limited than for the Great Lakes.
Except for lead, the sparse sampling data available generally indicate
that these pollutants, if present at all, are below detection limits (i.e.,
below the levels that can be detected by the sampling and analysis
methods used).60 For lead, concentrations have exceeded applicable
water quality criteria at some locations in the recent past.60
No widespread concentrations of metals exceed EPA water quality
criteria in the mainstem Chesapeake Bay. Yet, a limited number of
measured concentrations in the tidal tributaries to the Chesapeake Bay
exceeded EPA water quality criteria and State water quality standards
for cadmium and lead (as well as for copper and zinc). No exceedances
of water quality criteria or standards were reported for the remaining
air pollutants of concern within Chesapeake Bay.39
Case Studies of Exposure and Effects
As illustrations of exposure and effects resulting from pollutants
in the Great Waters, the following case studies are presented. These
case studies look at PCB concentrations in the food web in Lake
Ontario, the effects to humans from exposure to mercury through intake
of contaminated fish, the effects associated with low-level exposures to
pollutants of concern in Forster's terns, and the effects of nitrogen load-
ings on Chesapeake Bay. In reviewing these case studies, remember
that the overall contribution of atmospheric deposition to exposure
levels and effects is generally not well understood.
Subtle Effects Are Associated with Exposure to Low Levels
of Pollutants of Concern
Exposure to low levels of many pollutants of concern may result
in ecological or human health effects that are not easy to recognize. The
effects from high-dose exposures, such as acute toxicity and death, are
far easier to observe than those from low-dose exposures, which often
are delayed, long-term effects. In offspring, these effects may be the
result of low-level exposures to parents. As a result, subtle health effects
in wildlife and human populations resulting from low-level exposures
could be overlooked as conditions in the environment improve and expo-
sure levels decrease. This point is illustrated in the following study of a
Forster's tern colony (fish-eating birds) in Green Bay, Wisconsin.
In 1983 and 1988, research teams studied the reproductive suc-
cess of a colony of Forster's terns nesting on a waste disposal facility in
Green Bay as compared with a control population that was nesting on
an inland lake and that was not dependent on food sources in the Great
Lakes. In 1983, tern offspring from the Green Bay colony experienced
lower hatch rates of eggs, lower chick body weight, lower rates of chicks
learning to fly, and decreased parental care as compared with the
control colony. Within 17 days after hatching, 35 percent of the chicks
had died, and the birds had abandoned the area. Researchers linked
38
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Chapter Three
Answering the Scientific Questions of Section 112(m)
New Reports on the Effects
of "Environmental Hormones"
Mounting evidence indicates that many chemicals, including DDT, lindane,
atrazine, PCBs, dioxin, and mercury, that have been released to the environment
can disturb the hormonal (or endocrine) systems of humans and wildlife. Two
recent scientific articles describe the major concerns with the release of these
chemicals, often called "environmental hormones"—the variety of noncancer
effects, such as developmental and male and female reproductive impacts, linked
to chemicals that mimic estrogens (female hormones) and other hormones, and a
proposed link between exposure to environmental estrogens and breast cancer.
Disruptions to the endocrine system, especially during development in
utero or in very early life, and of the organs that respond to endocrine signals
are of concern because the effects caused by exposure during an organism's
development are permanent and irreversible, and they may go undetected until
an organism reaches adulthood and, for example, tries to reproduce.61
Environmental hormones work by being accepted by organs as a hormone,
but without producing appropriate effects. Exposure of fetuses to these chemicals
can profoundly disturb organ development. Organs that appear to be at particu-
lar risk for developmental abnormalities are those affected by female/male hor-
mones, including both female and male reproductive organs. In both sexes, the
external genitals, brain, skeleton, thyroid, liver, kid-
ney, and immune system are also potential targets
for endocrine-disrupting chemicals.61
In wildlife, exposure to endocrine-disrupting
chemicals has been associated with decreased fertility
in birds, fish, shellfish, and mammals; decreased
hatching success in fish, birds, and turtles; demascu-
linization and feminization of male fish, birds, and
mammals; defeminization and masculinization of
female fish and birds; and alteration of immune func-
tion in birds and mammals.61
In laboratory studies, mammary (breast) cancer
has been linked with environmental estrogens, such
as organic compounds (e.g., DDT or dioxins) and
polycyclic aromatic hydrocarbons (PAHs). In addition,
recent epidemiologic studies have found that breast fat and blood fats of women
with breast cancer contain significantly elevated levels of some chlorinated or-
ganic compounds compared with noncancer controls. Breast cancer, in the major-
ity of cases, is thought to arise from interactions between genetic and environ-
mental factors. It is hypothesized that environmental estrogens increase the risk
of breast cancer by mechanisms that include interaction with breast-cancer sus-
ceptibility genes.62
39
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Chapter Three
Answering the Scientific Questions of Section 112(m)
;:: Sculpin 1.7
>»**•
Shrimp 0.09
Figure 7. Biomagnification of PCBs
in the Lake Ontario food web, 1982.32
PCBs shown in parts per million.
these effects to elevated concentrations of PCBs in the chicks and eggs.
In 1988, the median concentrations of PCBs in the Green Bay colony
had decreased significantly from those measured in the 1983 study.
During the first 17 days of the 1988 study, certain types of effects for
the Green Bay colony—including hatching success, weight gain, and the
rate of chicks learning to fly—were comparable to those for the control
group in 1983. However, on day 18, chicks began to show
signs of "wasting" and by day 31, 35 percent of the young
had died—the same percentage that died within 17 days
in 1983. To date, "wasting" appears to be the most sensi-
tive effect in Forster's terns resulting from low-level expo-
sure to PCBs, and it appears to be delayed as exposure is
reduced. Also, because of the delayed onset of the effects,
if the 1988 study had been conducted for only the same
period of time as the 1983 study, incorrect conclusions
about environmental recovery would likely have been
drawn.
PCBs Concentrate in the Food Web
PCBs are a class of compounds that are persistent
in the environment and are known to be toxic to humans
and ecosystems. PCBs are associated with cancer, neuro-
logical effects, and effects on reproduction and develop-
ment in humans. In wildlife, they have been associated with premature
deaths, effects on reproduction, and immune system effects. Because of
low ambient concentrations in water, the importance of exposure routes
other than drinking water should be considered when assessing the
exposure and effects
of PCBs.
The most important route of exposure to PCBs is through intake
of food following biomagnification through the food web. This is illus-
trated by the concentrations of PCBs in plants and animals in the food
web in Lake Ontario (see Figure 7). Floating microscopic plants (phyto-
plankton) and animals (zooplankton) take in and retain PCBs. Fish then
eat these plankton, taking in the chemicals present in the plankton.
When an animal cannot break down or eHminate the PCBs it takes in,
the PCBs accumulate in the animal's fatty tissue. Soon, the animal has
higher concentrations than the surrounding environment. The process
leading to increasing concentrations of chemicals at higher levels of the
food web is known as biomagnification. Biomagnification continues up
the food web as predator fish feed on smaller fish, and as birds and
mammals (including humans) then feed on predator fish.
Biomagnification results in far greater concentrations of PCBs in ani-
mals than would be expected based strictly on concentrations in the
water.
40
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Chapter Three
Answering the Scientific Questions of Section 112(m)
1,000
f
•S,
100 -
8,6
g'S
Present WHO
"Safe Level"
(471)
Suggested Range
for "Safe Level"
Mean U.S. Intake
Intake Exceeded by 1% —
of U.S. Population
Intake Exceeded by 0.1 to 0.2%
of U.S. Population
Figure 8. U.S. daily intakes
of methylmercury versus World
Health Organization "Safe Levels."63
Current "Safe Levels" for Mercury May Not
Be Protective of Human Health
Mercury exists in the environment in three forms:
metallic mercury, methylmercury (and other organic
forms), and mercury salts. Metallic mercury is poorly
absorbed by the body, and high doses in humans may
result in no effects.38 Methylmercury and mercury salts, on
the other hand, have been demonstrated to cause serious
human health effects.38 Methyhnercury is of greatest
concern because it is readily absorbed into body organs and
tends to bioaccumulate to high levels in animals, including
fish and humans.
Exposure of humans to mercury may result in kidney
damage, damage to the brain and nervous system, and
developmental effects. Prenatal exposure to methylmercury
is of special concern because recent research indicates that
prenatal exposure to methylmercury concentrations fivefold
to tenfold lower than current World Health Organization
(WHO) "safe levels" may result in subtle neurological
effects in children, such as abnormal reflexes and delayed
motor skills development.63 As shown in Figure 8, 0.1 to
0.2 percent of the U.S. population (about 250,000 to
500,000 people) currently exceed the WHO "safe level" for
daily methylmercury intake. Based on the recent data
assessing the effects associated with prenatal exposure,
however, a lower limit to protect from developmental
effects may be warranted. As shown in Figure 8, a new
"safe level" of about one-tenth the current level has been suggested. It is
evident that a substantial fraction of the U.S. population exceeds this
suggested new level. The National Institute of Environmental Health
Sciences is performing studies to determine whether a lower limit
should be established.
Mercury is found naturally in the environment, and it is also
released from human activities such as fossil fuel combustion, waste
incineration, and other industrial processes. Subsequent atmospheric
deposition may lead to increased concentrations in aquatic ecosystems.
Human exposure to mercury generally is through the ingestion offish,
which bioaccumulate mercury in muscle tissue.63 Anthropogenic releases
of mercury, combined with naturally occurring mercury and the
bioaccumulation potential of mercury, may result in exposure of human
residents in the Great Lakes basin to levels of mercury that exceed the
current WHO and EPA guidelines for fish consumption. This risk is
greatest for population groups that consume affected fish from the Great
Lakes, such as some American Indian tribes.64
41
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Nitrogen is the Nutrient Controlling
Eutrophication in Chesapeake Bay
Eutrophication has been recognized as a
problem in the Great Lakes, Chesapeake Bay, and
coastal waters for over 30 years. In the Great Lakes
and other fresh waterbodies, phosphorus was recog-
nized as the nutrient of primary concern, and efforts
to reduce phosphorus loadings, such as removal of
phosphate from detergents and improved sewage
treatment techniques, resulted in substantial
phosphorus reduction in waterbodies and improved
water quality.40
However, in coastal waters such as the Chesa-
peake Bay, decreases in phosphorus loadings have
not resulted in significant decreases in eutrophica-
tion. Researchers now identify nitrogen, in forms
such as ammonium and nitrates, as the nutrient of
primary concern in the Chesapeake Bay and many
other coastal waters. Nitrogen loadings cause
increased eutrophication in waterbodies, and this can result in oxygen
depletion in the water or reduced oxygen levels, nuisance algal blooms,
dieback of underwater aquatic plants, and reduced populations of fish
and shellfish. This is significant in the context of atmospheric deposition
because up to 40 percent of nitrogen in Chesapeake Bay is estimated to
result from atmospheric deposition.40 Thus, atmospheric deposition
appears to be contributing significantly to eutrophication problems in
Chesapeake Bay and other coastal waters.
Chesapeake Bay has experienced a 20 percent decrease in water
column phosphorus concentrations since 1984, but water concentrations
of nitrogen have remained relatively constant.40 During this same time,
dissolved oxygen levels, an indicator of recovery from eutrophication,
have not increased. Eutrophication in Chesapeake Bay has contributed
to depleted fish and shellfish stocks, loss offish and plant habitats, and
losses of underwater aquatic plants related to increased algal growth
and decreased light penetration. Studies to improve the health of Chesa-
peake Bay focus on understanding how nitrogen cycles through the bay
and on techniques for decreasing inputs of nitrogen compounds into this
waterbody. Recently, tributary basin nutrient reduction goals were
established, which has focused attention on atmospheric deposition of
nitrogen as a potential source of controllable loadings.65
Conclusions Related to Effects
Section 112(m) of the 1990 Amendments directs EPA to assess the
environmental and human health effects of pollutants that are attribut-
able to atmospheric deposition to the Great Waters and to determine
whether pollutant loadings to the Great Waters cause or contribute to
42
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Chapter Three
Answering the Scientific'Questions of Section 112(m)
violations of drinking water standards or water quality standards. This
section reviewed some of the principal ecological and human health
effects associated with selected pollutants of concern in the Great
Waters. The following conclusions are drawn from this review of
currently available scientific information.
1. Some ecological effects and human health effects caused by
pollutants that are present in atmospheric deposition to
waterbodies are subtle, result from long-term exposures to
low levels of pollutants, and may be delayed in onset and
even occur over multiple generations.
The effects associated with the selected pollutants of concern often
result from long-term exposures to one or more pollutants present at
low concentrations. (For example, long-term exposure to low levels of
mercury may result in kidney or nervous system damage. Because of
gradual exposure and bioaccumulation in the body, the onset of these
effects may go undetected.) Similarly, exposure to many pollutants of
concern may have little or no measurable effect on the adult but may
result in developmental effects in the fetus or developing newborn.
For example, maternal exposures to certain pollutants may be passed
to a newborn through feeding or passed to a fetus across the pla-
centa, potentially resulting in adverse effects in the infant or in the
fetus, both of which are more sensitive than the adult to environmen-
tal pollutants. In addition, effects that have a delayed onset may
occur, and these delayed effects are often extremely difficult to detect.
2. Noncancer effects of the pollutants of concern are of great
concern, particularly for animals higher up in the food web.
Laboratory studies indicate that the selected pollutants of concern
have a wide range of effects on both wildlife and humans. Field stud-
ies indicate that certain Great Waters pollutants can cause immune
system effects, effects on reproduction, and neurological effects in
wildlife, thereby signalling concern that humans may also be exposed
to levels that cause these and other effects. Though many of the
pollutants are probable carcinogens, most cause noncancer effects
that are also of significant concern. For example, a majority of the
15 selected pollutants of concern may cause harder-to-detect develop-
mental effects, such as delayed development of motor skills. Addition-
ally, many of the pollutants of concern may cause brain or nervous
system damage. All of the pollutants of concern also can affect the
endocrine system, which may in turn affect reproduction, nervous
system function, and development of the immune system. These
effects may be as devastating to an individual person or animal as
cancer and may also have population impacts. Effects may also occur
after little or no latency period and may occur at very low exposures.
43
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Chapter Three
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Further, because exposure is cumulative, the potential for impacts on
the population is extremely high.
3. Though atmospheric deposition is a significant pathway into
the Great Waters for some toxic pollutants, the relationship
between atmospheric deposition and the effects on humans
and ecosystems is not clearly understood.
Recent research has indicated that atmospheric deposition is a sig-
nificant contributor of some toxic pollutants to the Great Waters;
however, the relationship—especially the quantitative relationship—
between atmospheric deposition and effects in (or risks to) humans,
animals, and plants, for most pollutants, is not clear. Many pollut-
ants of concern for atmospheric deposition also have a long history of
discharges to the Great Waters, and current levels of many of these
may be the result of recycling from the sediments. Thus, the
specific contribution of atmospheric deposition to exposure and
effects cannot be quantified at this time.
4. In many temperate estuarine systems, such as Chesapeake
Bay, atmospheric deposition of nitrogen compounds is a
major contributor to accelerated eutrophication.
Regulations to reduce phosphorus discharges have had limited suc-
cess in controlling eutrophication in coastal systems. Recent evidence
indicates that nitrogen is usually the limiting nutrient in temperate
estuarine systems. Moreover, for some waterbodies, such as Chesa-
peake Bay and Delaware Bay and potentially for many others, a
significant percentage of the nitrogen load is from atmospheric
deposition (see Table 8, page 55).
5. Persistence in the environment, tendency to accumulate hi
animal tissue, and toxicity to humans and other organisms
are important indicators of the hazard potential of air
pollutants that are deposited to waterbodies.
For identifying air pollutants of concern, these three characteristics
are most important. Pollutants with these characteristics have the
ability to cause health effects in humans and the environment; to
biomagnify in the food web, allowing for higher exposure levels to
animals at the top of the food web; and to remain in the environment
for long periods of time, increasing the opportunity for exposure.
44
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Atmospheric Transport
II
Releases from Natural i/j'/j/,Ij,,
and Anthropogenic Sources Wet Deposition
Indirect
Deposition
via Runoff
River Outflow
^•-^.
Tidal Exchange in Estuaries
Chemical
and Biological
Reactions i
, 1,, '. **" " " T>l
- " Salt Marsh Exchange
(Estuaries only)
Bottom Dwellers
"Exchange
Sediment
Exchange
Figure 9. Mass balance model for
lakes and estuaries.
Relative Loading: What Is the Relative Importance
of Atmospheric Deposition in Pollutant Loadings to the
Great Waters?
A critical step in evaluating atmospheric deposition to the Great
Waters is to assess the extent to which hazardous air pollutants actually
enter waterbodies from the air. This type of analysis enhances our
ability to attribute adverse human health and environmental effects to
atmospheric deposition and helps make it possible to trace the air
pollutants of concern back to the sources that release them.
Understanding the extent of atmospheric deposition requires an
analysis of the amount of a given pollutant that enters a waterbody over
some period of time, commonly referred to as the pollutant "loading." It
is necessary to analyze not only the total loading of a pollutant, but also
the relative loading (i.e., how the loading from atmospheric deposition
compares to that from other pathways, such as groundwater seepage
and inflow from connecting surface waterbodies, where portions of the
pollutant load may not be of atmospheric origin). Once a clear picture of
relative loading exists, the importance of atmospheric deposition to the
Great Waters can be understood and a determination can be made of
the possible measures for controlling air and water quality in an over-
all context.
The essential framework for evaluating the relative inputs of
chemicals to a body of water is an input-output budget, or "mass bal-
ance" model. In such a model, the total amounts of a given chemical
that enter and exit the waterbody by various pathways are estimated.
Figure 9 shows the basic features of
a mass balance model for lakes and
estuaries. Pollutants can enter lakes,
such as one of the Great Lakes or
Lake Champlain, from connecting
streams and rivers, groundwater
inflow, and atmospheric deposition.
Pollutants can also reenter lakes
through release from the lake bot-
tom. Atmospheric deposition occurs
as pollutants are carried down from
the air along with falling rain or
snow, settle onto water in the form
of dry particles, or transfer into the
water in the form of a gas. Atmo-
spheric deposition may occur either
as direct deposition (i.e., pollutants
are deposited directly from air to a
waterbody) or as indirect deposition
(i.e., pollutants are deposited from
Air/Water
Exchange DryParticle
Deposition
45
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
iliiyiijiThe Mass Balance
: IIIM'ft I1" "MI !l|iiiniii nil mi: i ii*iiif:i[i«^ UTii'viiiii <,'iiii
f'm'ass balance model is
_ _ 4llli«^^ i Sill!: SSriiiiii i: 'I >:.1"!:
essential framework for
estimating relative loadings
of pollutants to a waterbody.
The model establishes a proc-
e& for identifying and consis-
tently evaluating all ways
that pollutants can enter and
exit a waterbody.
"i i); , "' i , MI i
QnJy with a clear understand-
ing of all inputs and outputs
of a given pollutant can we
begin to understand the rela-
^|W importance of atmos-
pheric deposition.
air to land and enter a waterbody via runoff or seepage through ground-
water). Pollutant outputs from the lake include evaporation, stream and
river outflow, breakdown by chemical and biological processes, settling
and burial at the bottom, and seepage into groundwater. Pollutants
entering surface waterbodies may be diluted by mixing and may un-
dergo reactions that change their physical and chemical forms. Estuar-
ies such as Chesapeake Bay differ from lakes in that they are semi-
enclosed bodies of water where fresh water from the land mixes with
salt water from the ocean. Estuarine waters have physical and chemical
characteristics that make them different from fresh and salt waters.
The features of a mass balance model for estuaries differ significantly
from those of lakes because of the importance of tidal exchanges and the
influence of coastal marshes and waters.
The remainder of this section describes chemical mass balances
for the Great Waters to evaluate the relative loading of pollutants by
atmospheric deposition. The section begins by summarizing the current
understanding of atmospheric deposition processes and mass balances in
surface waters. The section then presents mass balance case studies for
selected pollutants and waterbodies and uses these case studies to
develop generalizations and conclusions that apply to the Great Waters
as a whole.
Current Understanding of Relative Loadings
A substantial body of knowledge exists concerning atmospheric
deposition processes and loadings to surface waters. Significant addi-
tional research is required, though, to better determine, with cer-
tainty, the atmospheric loadings of pollutants of concern to the Great
Waters and their relative importance in causing human health and
environmental effects. Table 6 provides an explanation of several scien-
tific terms that are relevant to relative loadings from the atmosphere,
including how airborne pollutants are brought to the earth by "wet"
and "dry" deposition processes, the degree to which airborne pollutants
are transferred "directly" versus "indirectly" to surface waterbodies, and
the influence of a pollutant's chemical and physical form on deposition
and cycling between environmental media. This table is followed by
answers to four basic questions that address the current scientific
capabilities for evaluating atmospheric deposition to the Great Waters.
1. Do We Have the Conceptual Understanding Required
to Estimate the Relative Atmospheric Loadings of Pollutants
to the Great Waters?
The mass balance approach, in which all pollutant loadings to, and
releases from, a waterbody are identified and estimated, provides an
appropriate conceptual framework in which to determine the relative
importance of atmospheric deposition in causing contamination in the
Great Waters. While the amounts of pollutants that enter and exit
46
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 6. Explanation of Atmospheric Deposition Terms
Term
Wet deposition
Dry deposition
Indirect
versus direct
deposition
Reentrainment,
Resuspension
Volatilization
Chemical
and physical
forms of
pollutants
Explanation
Pollutants in the atmosphere in a gaseous phase can enter water
droplets in the air by a variety of processes and be deposited to the
earth along with rain, snow, and other forms of precipitation.
Metals and organic chemicals that are bound to airborne particu-
lates also are incorporated into precipitation. Wet deposition of
gases and particles has been evaluated extensively by several inves-
tigators at several locations.
Dry particles in the air can settle onto water and land surfaces at
a rate that depends on the particle size, wind speed, and other
factors. Gaseous pollutants also can transfer from the air to the
water and land. Currently, methods for measuring dry deposition
have large uncertainties compared to methods for measuring wet
deposition, and there are no widely accepted methods for estimat-
ing how much dry deposition occurs. Recent studies, however,
suggest that chemical transfers between air and water play an
important role in the mass balance of systems like the Great
Waters.
Air pollutants are not only deposited directly to the surface of
waterbodies, but are also deposited to watersheds and then
discharged into the waters indirectly, through stormwater runoff,
tributaries, and groundwater seepage. Where the watershed is
large relative to the open water, indirect loading can exceed direct
loading. Although indirect loadings are included as a component of
a mass balance, procedures are not available for determining these
loadings with much certainty.
Reentrainment is the removal of deposited particles from a water
or land surface by air flow above the surface. Whether a particle
will be resuspended depends on the adhesion between the particle
and the surface, balanced against the lifting force created by wind
turbulence.
Previously deposited gaseous chemicals can be reemitted to the
atmosphere as the result of many factors, including chemical
reactions and changes in temperature or windspeed.
The chemical and physical form of a pollutant affects its mobility
in environmental media, its tendency to transfer between media,
and its toxicity. Significant aspects of pollutant forms and how
they influence pollutant behavior in the environment have been
identified. However, numerous uncertainties still exist, and
additional study of specific chemicals is needed.
47
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
surface waters by some pathways are difficult to quantify and require
new research initiatives, development of the mass balance framework
is straightforward.
2. Do We Currently Have Data of Sufficient Accuracy and
Precision to Estimate Relative Atmospheric Loadings
of Pollutants to the Great Waters?
With very few exceptions, the construction of a mass balance for each
pollutant has not been possible due to a lack of consistent, coherent,
and simultaneous measurements, on a pollutant by pollutant basis, of
all loadings to a waterbody. While technically possible, such inte-
grated measurements require a significant commitment in order to
generate adequate information to develop scientifically credible mass
balances.
3. Do We Have the Tools to Determine Atmospheric
Deposition Rates with Accuracy and Precision?
Methodologies of suitable accuracy and precision currently exist to
determine the rate of wet deposition of many chemicals to specific
locations in the Great Waters. For example, deposition of trace
elements and some organic pollutants during rainfall can be
adequately measured. Conversely, dry deposition of pollutants
attached to particles and the transfer of gaseous pollutants between
air and water can, at present, only be estimated by indirect methods.
Tools for accurately and precisely measuring dry deposition are not
yet available, but some are being developed.
4. What Is the Scientific View of Our Current Understanding
of the Processes Resulting in Atmospheric Deposition?
During the past 30 years, the scientific community has recognized
the importance of atmospheric deposition in causing surface water
contamination and has developed and refined models describing the
physical and chemical processes responsible for atmospheric deposi-
tion. At present, estimates have been made of atmospheric loadings
of a few specific pollutants to a few specific waterbodies, yet uncer-
tainties are associated with these estimates. Knowledge of processes
in the atmosphere and in surface waters is not sufficient to deter-
mine, with confidence, the magnitude and impact of atmospheric
deposition of all of the pollutants of concern to all of the Great
Waters. However, specific studies do indicate that the relative
contribution of pollutant loading from atmospheric deposition can be
significant.
48
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
Atmosphere: ~200kg
Volatilization
- 600-4,200 kg/yr
Atmospheric
Deposition
-167 kg/yr
River Outflow
~ 40 kg/yr
~ 20-50 kg/yr
Particle Settling
-3,000 kg/yr
Recycling
- 2,950 kg/yr
Water Column:
-7,200 kg
Sediment: ~ 5,000 kg
Figure 10. Mass balance of PCBs
in Lake Superior. Numbers presented
are approximations. Data taken from
reference 6.
Relative Loading Case Studies
As illustrations of relative contaminant loadings to the Great
Waters and other similar waterbodies, mass balances are presented
below for PCBs in Lake Superior, mercury in lakes in Wisconsin and
Sweden, nitrogen in several Atlantic estuaries, and cadmium in Dela-
ware Bay. To construct these mass balances, researchers used data on
the concentration, amount, and movement of pollutants in different
environmental media, as well as mathematical models to estimate
pollutant transfers into and out of waterbodies over time. This process
requires numerous assumptions and is filled with uncertainties. Never-
theless, as summarized below, these mass balance case studies
provide a strong indication that the relative contribution of
pollutant loading from atmospheric deposition can be substan-
tial, depending on the particular pollutant and waterbody.
The Atmosphere is Both a Major Contributor
to, and Recipient of, PCBs in Lake Superior
Of the organic chemicals for which a mass balance can be devel-
oped, PCBs have been studied the most because of their tendency to
bioaccumulate and because of their persistence, widespread distribution
in the environment, and toxicity. PCBs provide an interesting case
study because they have been banned from further production, although
they are still in use for limited purposes, and because they are still
apparently being released to the air. Several researchers have accumu-
lated sufficient information on the
amount and cycling of PCBs in Lake
Superior to develop a PCB budget (see
Figure 10). Lake Superior is the larg-
est of the Great Lakes, accounting for
more than 50 percent of the Great
Lakes water volume. In addition to
having a large surface area compared
to its drainage area, Lake Superior is
strongly influenced by atmospheric
interactions (for PCBs). Major inputs
to the lake include river flows (which
contain municipal and industrial
wastes) and atmospheric deposition.
PCBs may be lost from the lake by
flow through the St. Mary's River, by settling into the bottom sedi-
ments, by chemical or biological degradation, and by release to the air.
Mass balance calculations indicate that atmospheric deposition
currently contributes approximately 77 to 89 percent of the total yearly
input of PCBs to Lake Superior. Annual atmospheric loadings (per unit
49
-------
•.apler Three
fWgring'in.e Scientific Questions of Section 'fl2"lm)
" il;"'i;:
.'Hi I1-1,,,
i
Lid1;,,
ll||lllliii
mil nil i iniiiiiiiiin ',
f ! i1!1!1" '
1 B '»'*! "
t • i
The Lake Champlain Basin
Canada
j f- a JWissisquoi isay
1- -r*r • f
United States
Lake
of researchers
u _ University of
; ' r;i ; :••' : ') s'!|!- ""B"! t;i?' KhiganX' 'State" agencies' (^taie of'Vermont,1 Vermont Monitoring Cooperative),"
1 ; ;;:? 'r;;is " •' ; *"' ^>S~~-K> s;i'^^^^^^ "
.PMlJSililiiwItlitlWi^i^iWWWWlWild** .'bll"^.Ki.! 'J^i ',' j i'i* ,[fl «,aft jfo.
iThe project objective is to assess the magnitude and seasonal
yariatipris/jn the levelsi of atmospheric mercury and mercury
deposition in the Lake Champlain Basin (LCB). Emphasis is
also being placed on the processes that lead to indirect depo-
sition of mercury to Lake Champlain since the lake surface
represents only 5 percent of the drainage basin.
— - Results from tjj.e,first;year of monitoring, which com-
menced in December 3M, reveal thai mercury in precipita-1"
^p^'y|5r^^^g5ad^'"wi:i;h' the highest concentrations being
observed during trie warm months from May to August. The
total mercury wet deposition was similar to the observed
deposition in northern Michigan but less than the amounts
measured at southern Michigan sites.
Preliminary meteorological analysis of the atmospheric
mercury measurements revealed that the highest concentra-
tions of mercury in precipitation were associated with air
masses reaching the Vermont site from the northwest, out of
Canada. However, elevated mercury levels in the LCB are
also associated with air masses arriving from the southwest,.
from the Midwest Region. In comparison, the highest concen-
trations of mercury m precipitation recorded in Michigan are
' often asfOciatBdwitrTair masses reaching the Michigan sites
from the south-southwest.66'67
The ambient mercury levels observed in the LCB were
also similar to those measured in the State of Michigan,68
While fish consumption advisories are in effect for
Lake Champlain due to mercury and PCBs, it is unclear at
this time what fraction of the mercury in the fish is ac-
counted for by atmospheric deposition.
Inland Sea
MaUetts Bay
Broad Lake
South Lake
New York Vermont
I \.:l!ii'::i!,iK jiilii'il '^^
I iuiZ N.il.lijiijiijihjiij.id',:,1!1,::::![!:!»!!'; ;j/s,at ,,E ijiiii Lip,: j'i, i," 'i1:1'1 '.iliisir.iiii'iN! . jnZrini j: i, aijiiii! I1 ^b™1!11 s ,'viii. :4;!i|::i!:'!'.i ^i^'wwjiiF'^^iViiii'iiLbS1:!;::; j^i^'liistaiiKiijiiipipiiiSJJJp^^
nil ' i/inWllllill ir , hl'lill :,!';! ,ii. hlili!!:' ;!'l, 'llllb iii! i ii, !|P,i i,': .i .1 .'ilii- 'i Ifii.i"' il.iih ,j't irtl wl Ki'.i II! I
; :,!:ii I i •!,):,: i i,' ! ; L i,ti!;.;,, r:,;:,ifti
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
New Reports on Mercury Measurements
A recently completed report on the Lake Michigan Urban Air Toxics
Study (LMUATS) provides new insight on the levels and behavior of atmos-
pheric mercury in the southern Lake Michigan Basin.69 The report docu-
ments the measurements of total mercury performed simultaneously at three
locations during the summer of 1991 as part of the month-long intensive
study. This project was one of the first designed to observe the behavior of
the many different classes of compounds* as they moved from the urban/
industrial source regions across Lake Michigan.
The LMUATS revealed that ambient mercury concentrations, both
gaseous and particulate (i.e., attached to particles), are significantly higher
(approximately 5 times higher) in the Chicago urban/industrial area
compared to the levels measured at the same time in surrounding areas.
At the urban Chicago location, the levels of atmospheric mercury
varied greatly from day to day as well as within days for mercury
gas with the highest concentrations observed during the daytime
hours.
Measurements of particulate mercury provided new data on
the levels, particle size, and form of this critical pollutant. The
concentrations of this kind of mercury are significantly greater
than those observed previously in the Great Lakes Region
(10 to 50 times greater and also attached to larger particles than
expected). Since the 1991 study on Lake Michigan, over-water
measurements of mercury have been performed in the southern
Lake Michigan Basin, with levels exceeding those measured
during LMUATS.69 These findings indicate that most dry deposi-
tion estimates for mercury have probably underestimated the
mass loading of this toxic compound to both terrestrial and
aquatic systems. Additional studies are needed to allow us to
understand what factors are controlling the transport and deposi-
tion of mercury from the atmosphere.
*A comprehensive suite of hazardous air pollutants including other heavy metals, PCBs, PAHs, and selected pesticides were also
investigated during the study.
51
-------
Chapter Three
Answering the Scientific Questions of Section 112(m)
Atmosphere
Gaseous Particulate
-1.6 ng/m3 ~ 0.02 ng/m3
Water Column
Fish Dissolved Particulate
156ng/g ~lng/L ~25ng/g
Figure 11. Mercury in Little Rock
Lake, WI. Values shown are approxima-
tions.6
surface area) to the Great Lakes are similar to those to Chesapeake Bay,
suggesting rapid atmospheric mixing and transport of PCBs over North
America. PCB losses from Lake Superior occur primarily by
volatilization (evaporation), which represents nearly 90 percent of total
losses, while river outflow and burial in bottom sediments each repre-
sents only about 5 percent of total PCB losses. Based on these mass
balance calculations, PCBs appear to be gradually leaving Lake Superior
and transferring back into the atmosphere. It appears that the majority
of the decrease in PCB concentrations is due to volatilization.
Atmospheric Deposition Dominates Mercury Loadings to
Lakes Studied in Wisconsin and Sweden
The importance of atmospheric deposition in the cycling of mercury
in large lakes has been demonstrated in two major mercury investiga-
tions: (1) the "Mercury in Temperate Lakes Program" in Wisconsin, and
(2) an investigation of mercury in Sweden. Both studies indicate that
most of the mercury that enters these lakes comes from atmos-
pheric deposition and that slight increases in atmospheric mer-
cury loading could result in higher levels of mercury in fish.
The Wisconsin and Sweden studies show broad agreement.
The Wisconsin study indicates that atmospheric deposi-
tion accounts for the majority of the mercury in water, fish,
and sediments of Little Rock Lake and other similar lakes (see
Figure 11). Measurements of airborne particulate matter and
precipitation indicate that particulate mercury in the air falls
to the earth with rain. The lake ecosystem is very sensitive to
atmospheric inputs of mercury, to the extent that even small
increases in mercury loadings from the air could lead to
elevated levels in fish.
Similarly, analyses of the mercury flows into and out of
typical lakes in the southern half of Sweden show that mercury
enters lakes mainly through atmospheric deposition. The Swed-
ish study also suggests that a large portion of the mercury that
eventually enters a lake is first stored in the soils of forests
located within the lake's drainage area. Current atmospheric
deposition into drainage areas was found to be, on average, 10
times greater than the amount of mercury leaving the areas
through stormwater runoff. As a result, even if anthropogenic
emissions of mercury were to suddenly cease, mercury that has accumu-
lated in the soil would continue to be released to lakes from the forest
soils for a long time, perhaps several centuries.
52
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Chapter Three
Answering the Scientific Questions of Section 112(m)
41%
24%
D Municipal/Industrial Discharges
Q Elvers
• Sediment
• Air, Direct and Indirect 14%
• Salt Marsh 2%
Figure 12. Annual nitrogen loadings
to Delaware Bay. Values shown are
approximations.6
D Rivers
• Salt Marshes
• Air
72%
21%
Figure 13. Cadmium loadings to
Delaware Bay. Some unknown quantity
of the river input includes atmospheric
fallout into the watershed.6
Atmospheric Inputs of Nitrogen to Atlantic Estuaries
Appear Significant
Nitrogen, in forms available to living organisms, can enter estuar-
ies in a variety of ways. Of these, atmospheric deposition of nitrogen can
be important. For example, 10 percent of the total nitrogen inputs to
Long Island Sound is estimated to come from the direct deposition of
nitrogen compounds (nitrate and ammonium) from the air.™ Indirectly,
the inputs of nitrogen from the air to Long Island Sound are probably
much greater, since over half of the nitrogen entering the Sound comes
from upstream sources and urban runoff,70 and much of this nitrogen is
probably derived originally from the atmosphere. Studies of the water-
sheds of the entire Chesapeake Bay and of the upper Potomac River
have estimated that 25 to 40 percent and 28 percent, respectively, of the
nitrogen inputs to these systems come from atmospheric deposition.
In Delaware Bay, a more heavily urbanized estuary adjacent to
Chesapeake Bay, direct and indirect atmospheric deposition provide
about 14 percent of the annual nitrogen input (see Figure 12). During
late spring and early summer, however, atmospheric deposition to Dela-
ware Bay is estimated to provide 25 percent of the total nitrogen load-
ing, due to greater atmospheric loading coupled with lower river flows.
Comparison of these results for Chesapeake Bay and Delaware Bay
shows that these two nearby waterbodies receive similar inputs of nitro-
gen from the atmosphere. However, because of the more urbanized
nature of the area surrounding Delaware Bay (and the corresponding
higher nitrogen loadings from municipal and industrial discharges), the
relative atmospheric loading to the Delaware is slightly less, though still
significant.
The Atmosphere Contributes Important Loadings
of Cadmium to Delaware Bay
The mass balance for cadmium in Delaware Bay is one of the few
that is rather complete and realistic, as it considers both river inflows
and atmospheric deposition, the effects of tides, chemical transfers
between the Bay's water and bottom sediments, and outputs as well as
inputs to the estuary. More research is needed, however, to determine
the amount of cadmium that enters Delaware Bay from groundwater
and indirect atmospheric deposition.
Cadmium in Delaware Bay comes from three main inputs: rivers,
salt marshes, and direct atmospheric deposition. As presented in Figure
13, direct atmospheric deposition accounts for 7 percent of the cadmium
loading to the Bay. Rivers are the dominant cadmium input (72 per-
cent), but some fraction of the cadmium entering from rivers originally
comes from the air. Most of the cadmium loading is exported from the
Bay to coastal waters and, consequently, does not settle into bottom
sediments. The release of cadmium from the bottom sediments of the
bay into the water is seven times faster than the rate at which
cadmium gets buried in the bottom.
53
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Chapter Three
Answering the Scientific Questions of Section 112(m)
77-89%
Superior
-63%
Figure 14. Atmospheric loading of
PCBs to the Great Lakes. Arrows and
flow depict pollution that deposits from the
atmosphere directly to water surfaces and
travels through the Great Lakes system.
The percentages reflect the amount of
such pollution compared to that from all
other routes. For example, approximately
63% of Lake Huron's PCB loading is from
atmospheric deposition to the lake itself
and approximately 15% is from atmospheric
loading to the upstream lakes. The
remainder of Huron's PCB loading is from
nonatmospheric sources (approximately
22%). Data taken from reference 6.
Conclusions Related to Relative Loadings
The research findings and case studies lead to a number of conclu-
sions concerning the importance of atmospheric deposition to surface
water contamination. The conclusions presented below apply both to
surface waters in general and to the Great Waters in particular.
1. Although uncertainties still exist, case studies demonstrate
that atmospheric deposition may be an important, and in
some cases primary, contributor of toxic chemical contamina-
tion and nitrogen enrichment to the Great Waters.
Current understanding of relative loadings from atmospheric d.eposi-
tion is limited by a lack of data for many chemicals, undetermined
flows into and out of waterbodies for
many pathways, and insufficient
monitoring data. Nevertheless, rela-
tively complete information for a few
cases clearly shows that atmospheric
deposition may be a significant con-
tributor to contamination in surface
waterbodies, including the Great
Waters. For example, atmospheric
deposition is the primary way
mercury gets into some waterbodies
(see Tables 7 and 8 and Figure 11).
For PCBs, direct atmospheric deposi-
tion supplies approximately 77 to 89,
63, and 58 percent of the annual
PCB loadings to Lakes Superior,
Huron, and Michigan, respectively,
as shown in Figure 14. Moreover,
atmospheric deposition is the
primary way lead has been entering
the Great Lakes (Table 7). Atmospheric deposition contributes an
estimated 25 to 40 percent of the total nitrogen loading to Chesa-
peake Bay and a significant fraction of nitrogen loadings to other U.S.
coastal waterbodies (Table 8).
2. The relative importance of atmospheric loading for a specific
chemical in a given waterbody depends on characteristics of
the waterbody, properties of the chemical, and the location
of sources.
Broad generalizations concerning the relative importance of atmos-
pheric deposition are not possible because loadings depend on
numerous chemical-specific and site-specific factors. Chemical-specific
factors include pollutant form, persistence, and bioaccumulation
Ontario
Erie
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Table 7. Contribution of Atmospheric Deposition
to Total Loadings of Pollutants of Concern
for Selected Waterbodies
Waterbody
Lake Superior
Lake Michigan
Lake Huron
Lake Erie
Lake Ontario
Md Atlantic Bight
Lead
(*)
95
95
95
96
PCBs
(%)
76-89
58
63
20
13
POM*
(%)
96
96
80
79
72
aMeasured as benzo(c)pyrene.
NOTE: The data in Tables 7 and 8 represent several studies with varying
margins of error. The data are limited to pollutants for which rela-
tive loading estimates exist. Also, it is important to consider the
magnitude of inputs from sources other than the atmosphere when
comparing relative loadings. For example, if a lake is polluted
heavily by riverine inputs, its atmospheric contribution will be a
smaller percentage of the total. Likewise, a remote lake with no
other inputs will have a high atmospheric component, even if the
overall sum of pollutant inputs is small.
Table 8. Contribution of Atmospheric
Deposition to Total Loadings of
Nitrogen for Selected Waterbodies
Waterbody
Baltic Sea
Chesapeake Bay
Delaware Bay
Laholm Bay, Sweden
Narragansett Bay
New York Bay
Ocholockonee Bay, FL
Potomac River
Eehoboth/Indian River
Inland Bays, DE
Rhode River, MD
Nitrogen
(%)
25
25-40
14-25
7
12
10
100
28
8
40
potential, all of which affect transport processes, mobility, residence
times, and toxicity. Site-specific factors include the hydrology of a
given waterbody (e.g., river inflows and outflows, size of drainage
areas) and the location relative to natural and anthropogenic sources
of air pollution. All of these factors must be considered together to
develop specific conclusions for particular chemicals and waterbodies.
3. Chemicals in the environment may cycle between soil, air,
water, and biota for many years.
The amount of PCBs and other persistent semivolatile organic com-
pounds in air over the upper Great Lakes has not changed much
since the late 1970s, suggesting a continuing transfer between the
atmosphere and the terrestrial reservoir of these contaminants.
Because of the reservoirs of persistent chemicals, cycling between
environmental media occurs and results in continued atmospheric
deposition of certain organic chemicals without additional inputs.
Cycling of pollutants will continue for some time into the future.
Similarly, mass balance studies show that significant reservoirs of
mercury reside in fish, soils, and bottom sediments of waterbodies,
and these studies indicate that mercury may continue to cycle among
environmental media for years to come.
55
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Chapter Three
Answering the Scientific Questions of Section 112(m)
4. When possible, relative loadings to the Great Waters should
be evaluated using a mass balance approach.
Mass balance analyses provide an essential framework for determin-
ing the relative importance of various input sources and output
mechanisms in a waterbody, as well as a process for understanding
the transport and distribution of pollutants in the water and
estimating the length of time that a pollutant resides in any part
of an ecosystem.
Atmospheric loading information should not be overlooked as a source
of information when there are not enough data for a complete mass
balance, particularly when atmospheric deposition is suspected of
being a significant contributor to total loadings.
Natural Sources
Anthropogenic Sources
Figure 15. Examples of sources.
Sources: What Sources Are Significant Contributors
to Atmospheric Loadings to the Great Waters?
As summarized in Section 3.1, there is clear evidence of exposures
and adverse effects associated with toxic pollutants in some of the Great
Waters and, as discussed in Section 3.2, it appears that a large amount
of certain pollutants enter the water from the atmosphere. The next step
is to determine the source of the pollutants that are released to the air,
to help identify what, if any, emission reductions may be needed to
protect the Great Waters.
A source is any activity at any location that may release pollutants
to the air. As illustrated in Figure 15, pollutants may be released to the
air by natural sources and by anthropogenic, or manmade, sources.
Examples of natural sources include forest fires, volcanoes, windblown
dust and soil, and sea spray. Examples of anthropogenic sources include
industrial activities (such as waste incinerators, power plants, and
chemical manufacturers), pesticide applications at farms, and motor
vehicles. Some sources release pollutants to the air from a single point
at a fixed location, such as a smokestack at a factory; these sources are
commonly referred to as "point sources." Pollutants also may be
released over broad areas, called "area sources," such as when pesti-
cides volatilize after application to a farmer's field or when smoke rises
from a widespread forest fire. Area sources also may include small
sources in a given area that are too numerous to be counted individually
as point sources. Examples of these are dry cleaning facilities and house-
holds, both of which use various chemicals. Sources that are not station-
ary, such as cars, planes, and other vehicles, are considered "mobile"
area sources since they release pollutants to the air while moving.
In general, both local and distant air emission sources contribute
to a pollutant load at a given location. For the purposes of this report,
*Note that this definition of area sources is different from the definition in the Clean Air Act.
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Evaluation of Sources
l Source characterization:
Identifying and evaluating the
sources that emit pollutants of
concern to the air.
I Source apportionment:
Determining the relative con-
tribution of different sources
to the air pollution levels at a
given location, such as over a
waterbody.
local sources are defined generally as those sources located in States and
Provinces adjacent to the Great Waters. For example, local sources for
the Great Lakes are located in Illinois, Indiana, Michigan, Minnesota,
New York, Ohio, Pennsylvania, Wisconsin, and Ontario, Canada.
Distant sources are sources located outside the States and Provinces
adjacent to the Great Waters. Both local and distant sources include
natural and anthropogenic sources and area and point sources.
Determining what sources and source categories (i.e., groups of
individual sources having similar activities and air emissions) are
significant contributors to atmospheric deposition to the Great Waters
requires two basic tasks. First, sources must be characterized to identify
what the sources are, where they are located, and what pollutants they
emit. Source characterization includes identifying all sources that
release a given chemical, grouping sources into categories, measuring or
estimating the amounts of chemicals released to the air from individual
sources, and examining the relative importance of each source category
in the total atmospheric loading of a given chemical. Source character-
ization also includes analyses of the identity, form, and relative concen-
trations of chemicals released from a source, information that can be
used to link pollutants found in the air with a particular source or
source category.
Second, air pollution levels at a given location, such as over a
waterbody, must be apportioned to various sources that may have emit-
ted the pollutants. Linking air pollution with sources is a complicated
task, as air pollution at any one location usually consists of a mixture of
chemicals released from many sources, including some that are nearby
and others that are far away. Source apportionment is further compli-
cated by complex and ever-changing weather conditions, variations in
emissions from a given source, and changes in the chemical and physical
forms of pollutants as they move through the atmosphere. Scientists
have developed and are using a variety of mathematical models as tools
for determining what sources are contributing most to air pollution
levels at a given location, such as over the Great Waters.
In the remainder of this section, important sources of air pollutant
emissions are identified and an evaluation is made of which sources
contribute significantly to atmospheric deposition to the Great Waters.
The section begins with a review of the current understanding of
source characterization and source apportionment. Source case studies
are then presented, followed by conclusions for the Great Waters.
Current Understanding of Sources of Air Pollutants
Over the last several years, a large amount of information has
been collected to identify the major anthropogenic sources of toxic air
pollutants. Substantial new information is currently being collected by
EPA to identify and inventory sources in the United States that emit
mercury and other pollutants to the air. Nevertheless, at present, a
57
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Chapter Three
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Cadmium, Lead,
Mercury, Nitrogen,
Polycyclic Organic
Matter (POM),
Dioxins, Furans
Utilities
Cadmium,
Hexachlorobenzene,
Mercury, POM,
Dioxins, Furans
Municipal Waste Combustors
Lead, Nitrogen,
POM
Motor Vehicles
Figure 16. Pollutants of concern
emitted from selected sources.
complete and comprehensive inventory of the locations of particular
sources and the amounts of individual toxic pollutants that each source
emits to the air is lacking. This basic source characterization informa-
tion is needed to predict the transport of toxic air pollutants from
sources to the Great Waters and also to apportion existing air pollution
levels in the vicinity of the Great Waters to sources. In addition, there is
considerable uncertainty regarding the relative importance of local and
distant sources to air pollution levels over the Great Waters. Answers to
five basic questions that summarize current scientific knowledge about
these sources are provided below.
1. What Sources Emit Great Waters Pollutants of Concern
to the Air?
Many source categories of air pollutants of concern for the Great
Waters have been defined, and chemicals associated with each source
category have been identified. These categories include primarily
industrial activities and processes involving combustion. Less infor-
mation is available on natural sources and some types of area
sources, although several of these sources are known to emit certain
pollutants of concern. In some cases, there also is limited understand-
ing about the original source of certain pollutants that appear to be
originating from natural sources. For example, emissions of mercury
from soils have historically been classified as natural sources when,
in fact, a substantial portion of the mercury may have been deposited
to soils originally from human activities and then resuspended in the
air. In cases such as this, the current source (i.e., the soil) may be
distant from, and have quite different release characteristics from,
the original anthropogenic or natural source. Table 9 identifies key
sources known to emit pollutants of concern, and Figure 16 identifies
several pollutants of concern emitted from three important source
categories: utilities, municipal waste combustors, and motor vehicles.
2. How Good Are Available Emissions Data for the Various
Sources?
The quality of available data on the emission of toxic air pollutants
from individual sources varies widely. For some source categories,
such as chemical manufacturing, data on the composition and rate of
emissions are of good to excellent quality. For other sources, data on
the types and rates of pollutants emitted are incomplete, and emis-
sion estimates are crude. For example, the rates of emissions of
metals and persistent organic compounds in the States around the
Great Lakes, Lake Champlain, and Chesapeake Bay are difficult to
assess because of the diversity of emissions data reported by several
research groups. For most of the metals, emission estimates differ by
a factor of 10 or more and are continually being revised.
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Chapter Three
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Table 9. U.S. Sources of Air Pollutants of Concern3
PoEutant
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
cc-HCH
Lindane
Lead and compounds
Mercury and compounds
PCBs
Polycyclic organic matter
2,3,7,8-TGDF
2,3,7,8-TCDD
Toxaphene
Nitrogen compounds
Sources of Air Emissions
Fossil fuel combustion; aluminum production; cadmium, copper, lead, and zinc smelting; iron
and steel production; battery manufacturing; hazardous waste and sewage sludge incineration;
municipal waste combustion; petroleum refining; lime manufacturing; cement manufacturing;
pulp and paper production; combustion of waste oil; pigment manufacturing; soil-derived dust-
volcanoes. '
Insecticide application11; volatilization from soils, water, and treated building foundations due to
past insecticide application; suspension of eroded soil particles.
Insecticide application13; volatilization from soils and water due to past insecticide application
Insecticide application11; volatilization from soils and water due to past insecticide application.
Manufacture of chlorine and related compounds; combustion of materials containing chlorine;
pesticide manufacturing; municipal waste combustion; fungicide application13; volatilization from
soils and water due to past fungicide application.
Insecticide application13; volatilization from soils and water due to past insecticide application
Insecticide application13; volatilization from soils and water due to past insecticide application
Fossil fuel combustion; aluminum production; lead smelting; ferroalloys production; iron and steel
production; battery manufacturing; hazardous waste and sewage sludge incineration; municipal
waste combustion; petroleum refining; lime manufacturing; cement manufacturing; asphalt and
concrete manufacturing; pulp and paper production; combustion of waste oil; paint application1";
motor vehicles'3; forest fires; suspension of eroded soil particles; volcanoes.
Fossil fuel combustion; copper and lead smelting; hazardous waste, municipal waste, medical
waste, and sewage sludge incineration; lime manufacturing; cement manufacturing; chlorine and
caustic soda manufacturing; paint application13; suspension of eroded soil particles; evasion from
soils and water; volcanoes.
Incineration and improper disposal of PCB-contaminated waste; disposal of waste oil; malfunction
of PCB-containing transformers and capacitors; electrical equipment manufacturing; pulp and
paper production; volatilization from soils and water; municipal solid waste incineration and
unregulated combustion.
Combustion of plant and animal biomass and fossil fuels; municipal waste combustion; petroleum
refining; steel production; coke byproduct recovery; aluminum production; plywood and particle
board manufacturing; surface coating of auto and light duty trucks; asphalt processing; dry clean-
ing (petroleum solvent); fabric printing, coating, and dyeing; forest fires.
Hazardous, industrial, and medical waste and sewage sludge incineration; municipal waste
combustion; combustion of fossil fuels and organic materials containing chlorine; byproduct of
various metals recovery processes, such as copper smelting; accidental fires of treated wood
products and PCB-containing transformers and capacitors; improper disposal of certain chlori-
nated wastes; pesticide production, application, and spills; pulp and paper production; volatiliza-
tion from, and erosion of, dust from landfill sites; forest fires.
Hazardous, industrial, and medical waste and sewage sludge incineration; municipal waste
combustion; combustion of fossil fuels and organic materials containing chlorine; byproduct of
various metals recovery processes, such as copper smelting; accidental fires of treated wood
products and PCB-containing transformers and capacitors; improper disposal of certain chlori-
nated wastes; pesticide production, application, and spills; pulp and paper production; volatiliza-
tion from, and erosion of, dust from landfill sites; forest fires.
Insecticide application13; volatilization from soils and water due to past insecticide application
Fossil fuel combustion and other types of combustion; fertilizer application; animal waste.
*Data for this table are taken from References 5, 13 through 27, 71, and 72.
Not currently a significant source in the United States due to manufacturing restrictions.
59
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Chapter Three
Answering the Scientific Questions of Section 112(m)
3. What Local Sources Are Important Contributors of Pollutants
of Concern to the Great Waters?
Ongoing studies in the United States and Canada have identified
and characterized local sources around the Great Waters for many
pollutants of concern. Major local sources of metals include fossil fuel
combustion in industrial, commercial, and residential units; munici-
pal waste combustion and hazardous waste and sewage sludge incin-
eration; and various manufacturing processes, such as cement
production. Polycychc organic matter originates locally from fossil fuel
and biomass combustion, petroleum refineries, motor vehicles, and
industrial, commercial, and residential units. Pesticide application is
an important local source-of pollutants to many Great Waters, such
as Chesapeake Bay and other coastal waters. The impact of local
sources is also influenced strongly by the location of large point
sources relative to the waterbody. For example, 50 of the largest U.S.
power plants (as judged by emissions of sulfur oxides) are found in a
belt from Missouri to Illinois, Indiana, Michigan, Ohio, West Virginia,
and Pennsylvania. Many of these States are adjacent to the Great
Lakes region. Lake Champlain and Chesapeake Bay also are located
near significant sources.
4. What Distant Sources Are Important Contributors of
Pollutants of Concern to the
Great Waters?
Although no definitive information exists that indicates in precise
quantitative terms the relative contribution of local and distant
sources, evidence strongly suggests that distant sources can contrib-
ute a significant amount of air pollution over the Great Waters. The
extent to which pollutants reach the Great Waters from distant
sources depends on many factors, including the height of emission
stacks, temperature and velocity of exhaust gases, meteorological
conditions, and the physical and chemical forms of the pollutants.
Some distant sources believed to be responsible for pollutants
deposited to the Great Waters are located in other U.S. regions and
also in Canada. A portion of some pollutants over the Great Waters
probably originates from sources in other countries. For example,
significant amounts of air pollutants are emitted in Mexico from
motor vehicles and metals production plants. Also, some pesticides
that are present in the Great Lakes are still being used in the
Caribbean and Mexico but are restricted from use in the United
States and Canada. Pinpointing the sources of some pollutants
deposited to the Great Waters is difficult because these pollutants are
widely distributed throughout the United States and other countries,
even showing up in such remote locations as the Arctic. Pollutants
such as PCBs, which exist as particles or in the gaseous phase, may
be deposited to the ground and returned to the air many times. This
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Chapter Three
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Table 10. Source Apportionment Techniques
Type of Model
Dispersion
Receptor
Hybrid
, Description
Traces pollutants from sources to the air at various locations, such
as over waterbodies and land. Can quantify relative contributions
from a particular point source. Uses data on meteorological condi-
tions and the amount of pollutants emitted from particular sources
to evaluate pollutant dispersion in the atmosphere and estimate
the airborne concentrations at locations of interest. Requires
detailed data on the location and emission characteristics of vari-
ous sources, which are often lacking. Historically, the primary tool
for linking sources to air pollution levels, although limitations of
dispersion models have led to the development of receptor models.
Traces pollutants in the air at various locations, such as over
waterbodies and land, back to particular source types. Can esti-
mate contributions from a group of sources with similar emissions
rather than relative contributions from a particular source. Uses
data on the air pollution characteristics at the location of interest
and on the composition of source emissions (not including data on
meteorological conditions) to determine the likely responsible
sources based on the premise that sources can be identified by
unique emission characteristics (such as the forms and relative
amounts of individual pollutants). The effectiveness of this model-
ing approach is often limited by a lack of adequate "source profile"
data (sometimes called "source signatures") that allow air pollution
to be linked to particular source types.
Similar to receptor models, but also consider meteorological data.
Important for assessing how much air pollution over a receptor
comes from distant sources.
phenomenon, referred to as the "grasshopper effect," can result in
long-distance transport of pollutants and similar background concen-
trations of air pollutants worldwide.
5. Are Sufficient Data and Techniques Available to Relate
Air Pollution Levels Over the Great Waters to Particular
Sources or Source Categories?
There is a general understanding of
the major factors that affect the trans-
port of air pollutants between their
release from the source and their
downwind locations, as well as a gen-
eral understanding of how these factors
interrelate. Based on this knowledge, a
variety of techniques have been devel-
oped that can, in limited instances,
relate air pollution levels over the
Great Waters to particular sources.
Primary source apportionment tech-
niques include "dispersion" models,
"receptor" models, and "hybrid" models
(see Table 10). In most cases, these
techniques have not been fully vali-
dated, and they lack complete and
reliable input data, such as sufficiently
detailed data on the composition and
rate of emissions from some sources.
Source apportionment methods and
capabilities are especially weak for air
pollutants that are widespread in the
environment, travel over long dis-
tances, and/or are emitted in large
quantities from natural sources or
broad area sources.
Source Case Studies
This section presents source case studies for four pollutants of
concern in the Great Waters. These cases identify the principal local
and, when possible, distant sources contributing to air pollution levels.
Fuel Combustion, Especially Residential Wood Burning,
is a Primary Source of PAHs
PAHs, a subset of POM, appear to be released from a wide variety
of sources. The results of a recent study that analyzed the contributions
of various PAH sources in eastern North America are shown in Figure
17. The primary source of PAHs was stationary fuel combustion (nearly
61
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Estimated Emissions, tons/year
5,000
48%
Industry Stationary
Fuel
Combustion
Solid
Waste
Incineration
Figure 17. Sources of PAH emissions
in eastern North America, 1992.
50 percent), which includes commercial and residential wood, coal, oil,
and other fuel combustion, as well as electric power generation. In fact,
residential wood combustion alone accounted for over 30 percent of the
total PAH emissions in this study.
PAH releases in the United States appear largest in a wide diago-
nal belt extending from southern Illinois to the mid-Atlantic States and
southern New England. Many of the largest U.S power plants are found
in this belt and are known to emit large
amounts of PAHs that could deposit in
" the Great Lakes, Chesapeake Bay, and
other Great Waters. Major aluminum
smelters also are significant sources of
PAHs; some aluminum smelters are
located in States adjacent to and near
the Great Lakes, and others are in
States that border Chesapeake Bay.
Other studies have found that the
relative importance of particular sources
of PAHs can be exceedingly variable.
One study in New Jersey, for example,
found a large seasonal variation in emis-
sions of benzo(a)pyrene, a specific PAH.
During the nonheating season, 98
percent of benzo(a)pyrene emissions (183
kg) was estimated to come from motor
vehicles, while during the heating sea-
son, 98 percent of benzo(a)pyrene emis-
sions (6,135 kg) was from residential
wood burning. Another study found that
within a particular source category (such
as primary metals production), and even
within a specific industry (such as alu-
minum reduction facilities), PAH emissions at individual facilities typi-
cally vary by an order of magnitude or more, depending on the process
and raw materials involved.
Lindane Is Emitted from Sources Outside North America
The pesticide lindane, which consists mostly of y-hexachlorocyclo-
hexane (y-HCH), demonstrates the importance of global sources and
long-distance transport in atmospheric deposition. Though lindane is
available in both the United States and Canada, its use as a pesticide is
severely restricted. Yet lindane is still found in the Great Waters. Based
on investigations of global wind patterns and lindane concentrations in
the Arctic, it has been hypothesized that lindane deposited to the Great
Waters may originate from as far away as India, China, or the former
Soviet Union. Other international regions, such as Latin America, may
also be significant sources.
Mobile
Sources
Open
Sources
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Chapter Three
Answering the Scientific Questions of Section 112(m)
D Stationary Fuel Combustion 57%
II Mobile Sources 38%
• Industrial Processes 3%
• Solid Waste and Miscellaneous 2%
Figure 18. Anthropogenic sources
of nitrogen oxide emissions in 1990.
Lindane and other pesticides are used most extensively in Asia in
the spring. During spring storms in the Asian deserts, these pesticides
can become airborne in the gaseous phase or as very small dust par-
ticles and become subject to long-distance transport in the atmosphere.
Current understanding of meteorologic processes and wind patterns is
consistent with the possibility of hndane-contaminated air from Asia
blowing over the Pacific Ocean to the United States and beyond. Such
long-distance transport of lindane, however, has only been hypothesized
at this time and further study would be needed to obtain evidence of
long-distance transport. During atmospheric transport, some of the
y-HCH in lindane naturally changes into another chemical form,
a-hexachlorocyclohexane (cc-HCH). Measurements of the relative
amounts of y-HCH and cc-HCH can be used to evaluate how long the
lindane has been in the air and how far it has travelled from possible
sources.
Fossil Fuel Combustion and Motor Vehicles
Are Major Sources of Nitrogen Emissions
Nationwide studies have determined that nitrogen is released to
the atmosphere in various forms from a wide variety of industrial, com-
mercial, and residential fuel combustion sources. As shown in Figure 18,
the two primary U.S. sources of nitrogen oxide (NOX) emissions in 1990
were stationary fuel combustion (such as power plants) and motor
vehicles.40 Trends from 1982 to 1991 indicate that emissions from mobile
sources have decreased, while emissions from stationary fuel combustion
have increased. No cap on NOX emissions is required by the 1990
Amendments. Therefore, with continued growth, it is probable that NOX
emissions will start increasing again after the turn of the century.73
Separate studies in the Chesapeake Bay region yield the same
basic conclusion about nitrogen sources. One study determined that the
majority of nitrogen compounds in air over Chesapeake Bay are emitted
from power plants and motor vehicles.40 Many large power plants are
found in the mid-western, eastern, and southern parts of the country,
with a higher density of plants in a few regions, including the region
west and south of Chesapeake Bay.
Many Mercury Sources Are Located Outside
the Great Lakes Region
A number of studies have developed interim emission estimates
for mercury in the continental United States. One 1984 study (based on
1980 data) estimated that natural and anthropogenic sources combined
release roughly 1,700 tons of mercury to the air each year. More recent
EPA studies estimate that anthropogenic sources account for less than
one-third of this total.74 The 1984 study also found that only a small
portion of the total release came from States that are adjacent to or
near the Great Lakes. Mercury emissions from more distant States,
such as those in the Rocky Mountain region and along the Pacific
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Ocean, appear to contribute much larger fractions of the total mercury
loading to the air. These conclusions are still highly uncertain, however,
because dispersion modeling was not performed as part of the study.
The authors did estimate that almost 25 percent of airborne mercury
comes from unknown locations. As part of the EPA Mercury Study
(required under section 112(n)(l)(B) of the Clean Air Act, as amended in
1990), long-range transport dispersion modeling is being performed to
address this issue. The findings from this effort will be presented in
1994 in the Keport to Congress on the Mercury Study.
Preliminary results also provide an indication of the types of
sources that add to mercury levels in air over the Great Lakes. Waste
incineration and fossil fuel combustion have been identified as major
anthropogenic source categories for mercury emissions in the Great
Lakes region. Natural sources also are an important source. One study
suggests that a significant portion of the mercury released to air comes
from natural sources such as the release of mercury from surface waters
and the resuspension of soil particles. It is unclear, however, how much
of these "natural" emissions are actually the result of mercury buildup
in the environment caused by past anthropogenic releases.
Conclusions Related to Sources
Section 112(m) requires an assessment of air pollution sources
that are responsible for the atmospheric deposition of toxic chemicals to
the Great Waters. Based on available research findings concerning air
emission sources, the following overall conclusions can be drawn.
1. Although atmospheric deposition appears to be an important
way for some pollutants to enter the Great Waters, identifying
and characterizing the specific sources that emit the pollut-
ants is difficult.
In general, major sources that emit pollutants of concern to air are
reasonably well known, although reliable emissions data are
frequently lacking. Characterizing the emissions from a given source
through measurements is often very expensive and, in some cases,
extremely difficult to perform. As a result, emissions are frequently
determined by estimation techniques, which are less accurate and
frequently yield widely varying results across different research
groups. The current lack of reliable emission data and lack of detailed
emission inventories severely limits the ability to link toxic air pollu-
tion over the Great Waters to particular sources.
2. The specific sources and source categories contributing
to atmospheric deposition to the Great Waters are not well
known.
Many of the sources of many of the pollutants of concern have been
identified. Yet, to adequately identify the specific sources or source
categories responsible for particular air pollutants deposited to the
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Chapter Three
Answering the Scientific Questions of Section 112(m)
Great Waters, more complete and accurate data are needed to evalu-
ate both the emissions from individual sources and the concentra-
tions and deposition rates of airborne pollutants over a waterbody.
Source apportionment techniques also need continued modification,
improvement, and verification.
3. Atmospheric loadings to the Great Waters may be derived
from local, regional, and global sources.
Among other evidence, the observed presence of current-use pesti-
cides on untreated crops adjacent to treated fields demonstrates the
importance of local release and transport over short distances. The
importance of regional sources and cycling to mercury deposition has
been demonstrated in both North America and Europe. The presence
of persistent organic compounds in the Arctic and Antarctic is
evidence that long-distance transport in air and subsequent deposi-
tion is an important global pathway for these chemicals. Similarly,
atmospheric mixing allows northern hemispheric emissions of
elemental mercury to be transported to the southern hemisphere,
leading to elevated mercury concentrations in fresh water and
marine fish in areas far removed from local sources.
4. The relative contribution of local sources and distant sources
to atmospheric deposition to the Great Waters is uncertain.
Available emissions data indicate that many pollutants of concern
originate from some sources that are near particular Great Waters,
as well as some sources that are located in distant regions. The
tendency for pollutants to deposit near their source or to move long
distances in the atmosphere depends on a number of factors, includ-
ing the height of release points, the temperature and velocity of emis-
sions, meteorological conditions, and the physical and chemical forms
of the pollutants. Kesults from several recent studies allow for some
generalizations for certain pollutants, but more research is needed to
determine how much of the pollution deposited to the Great Waters
from the air comes from local versus distant sources.
5. The environment may act as an important reservoir or source
of persistent contaminants that have been released to air
previously. Because of pollutant cycling in the environment,
atmospheric concentrations of some pollutants may not corre-
spond closely to current source emissions.
Understanding the relative contribution of various sources is further
complicated by the fact that certain persistent pollutants cycle among
air, soils, surface water, sediments, and other environmental media
for extended periods. In many cases, it is possible that sizable frac-
tions of some pollutants entering the Great Waters from the air
today are not coming from current emissions, but rather are the
result of continued cycling in the environment.
65
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Chapter Four
Conclusions and Recommendations
Pollutants emitted to the atmosphere are transported various
distances and can be deposited to aquatic ecosystems far removed from
their original sources. Scientific studies show that this atmospheric
deposition is often an important factor in the degradation of water
quality and associated adverse health and ecological effects.
The potential for air pollutants to affect water quality has become
increasingly apparent over the last two decades. Stringent controls
placed on direct discharges to surface waters have had significant but
limited results, making diffuse, or nonpoint, sources of water contami-
nation more important by comparison. Water quality programs have
begun to address such nonpoint sources as agricultural and urban
runoff. Studies evaluating the loading of pollutants through atmospheric
deposition indicate that the atmosphere must also be considered a
nonpoint source of pollution that must be controlled in order to meet
water quality goals.
Concern about the impact of atmospheric deposition on water
quality was the basis for the inclusion of section 112(m) (i.e., the "Great
Waters" provision) in the Clean Air Act, as amended in 1990 (1990
Amendments). The purpose of this section of the 1990 Amendments is
to evaluate the impact of hazardous air pollutants on the Great Lakes,
Chesapeake Bay, Lake Champlain, and coastal waters and to determine
whether further reduction of HAPs is needed to prevent serious adverse
effects on human health and the environment. To determine if further
action is needed, several steps in the decision process are necessary and
are inherent in the report requirements posed in section 112(m). Essen-
tially, the questions that must be addressed are:
1. Do HAPs deposited to aquatic systems cause or contribute to
serious adverse effects to human health or serious or wide-
spread adverse effects to the environment or does atmospheric
deposition of hazardous air pollutants result in exceedances of
water quality standards or criteria?
2. If adverse impacts are occurring, what proportion of the
exposure is due to airborne pollutants as opposed to
waterborne pollutants?
3. If deposition from the air is significant, what sources are
emitting these pollutants?
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Chapter Four
Conclusions and Recommendations
This report evaluated 15 chemi-
cals that are significant water
pollutants on the list of Clean
Air Act HAPs (except for nitro-
gen compounds and dieldrin)
and are known to be deposited
from the atmosphere. They are:
Cadmium and compounds
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
a-HCH
Lindane
Lead and compounds
Mercury and compounds
PCBs
Polycyclic organic matter
2,3,7,8-TCDF
2,3,7,8-TCDD
Toxaphene
Nitrogen compounds.
Other pollutants will be evalu-
ated in the future and will be
included, as appropriate, for
recommended action. Likely
additions to the list are bioaccu-
mulative chemicals of concern
(BCCs) targeted for action by the
proposed Water Qualify Guid-
ance for the Great Lakes System
(58 PR 20802) that have
significant atmospheric sources.
4. Will regulations mandated by the 1990 Amendments address
these sources adequately, and, if not, what regulatory action is
recommended to control these air sources to prevent adverse
effects? What regulatory revisions are recommended under
other Federal laws?
The requirement to include non-Clean Air Act recommendations
makes it clear that the intenHs for section 112(m) to identify what
needs to be done in a broad arena and with a multimedia approach to
prevent adverse effects caused by hazardous air pollutants that have
been deposited to significant U.S. waterbodies.
This chapter summarizes findings on the impact of air pollutants
on water quality and aquatic resources, discusses EPA rationale for
decisionmaking at this time, and presents EPA's recommendations.
Future biennial Great Waters reports to Congress will provide
updated scientific information and address further regulatory needs.
The Clean Air Act studies on mercury and on electric utilities, with
reports to be published in 1994 and 1995, respectively, will further
augment information on hazardous air pollutants that are of concern in
the Great Waters. Findings from those reports will also be used in
subsequent Great Waters reports to Congress.
Conclusions
Water quality conditions for most of the Great Waters have
improved substantially over the past two or three decades. This
improvement demonstrates the effectiveness of Federal, State, and local
programs of environmental legislation and regulation, as well as public
and industry cleanup efforts. Most significant are water program
accomplishments under the Clean Water Act (CWA) (see sidebar on
page 69). Programs under the Clean Air Act (e.g., the phaseout of
leaded gasoline), the Toxic Substances Control Act (TSCA, e.g., banning
the use of PCBs), the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA, e.g., the banning of DDT), and other Federal laws have
also contributed to water quality improvements. A summary of relevant
EPA regulatory programs and regulations is provided in Appendix C.
As major reductions in direct discharges to surface waters were
achieved, the air contribution to water quality and related ecosystem
problems became more apparent. Despite the water quality
improvements that have been made, the Great Waters ecosystems are
far from fully recovered. In order to attain water quality goals and
ecosystem protection, the atmospheric component of the water quality
problem must be addressed.
Section 112(m) of the Clean Air Act, as amended in 1990, is only
one part of a comprehensive program to reduce emissions of hazardous
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Chapter Four
Conclusions and Recommendations
Pollutant Reductions
Resulting from the
Clean Water Act
The States and EPA have imple-
mented many important features
of the CWA in the past 20' years,
including:
• The development^ water
quality standards by each
State
• A massive construction
program for wastewater
treatment plants
• Monitoring and reporting
on the status of the States'
waterbodies
• The National Pollutant Dis-
charge Elimination System
(NPDES), a program that
requires permits for all dis-
chargers and sets technology-
based or water-quality-based
effluent limits for toxics from
industrial and municipal
facilities.
air pollutants, thus reducing pollutant loadings to the Great Waters.
In addition to the studies required by the 1990 Amendments, there are
significant regulatory requirements for hazardous air pollutants, many
of which will reduce emissions of Great Waters pollutants of concern.
Some of these requirements include vehicle emission standards, refor-
mulated fuel requirements, NOX emission control requirements under
the acid rain and ozone programs, and emission standards for station-
ary sources. Appendix D outlines specific activities required under
section 112 and lists the Great Waters pollutants that may be affected
by these activities. (Appendix E outlines EPA's progress under section
The most important conclusions of this Great Waters report are
related to scientific concepts concerning characteristics of the pollutants,
their transport through air, and their impacts after being deposited to
waterbodies. The atmospheric transport and deposition of pollutants
and their potential to affect human health and the environment are
concepts that are widely accepted by scientists in the field, yet there is
still much to learn. However, some basic information is quite clear and
very important in any discussion of these pollutants.
The effects that Great Waters pollutants of concern can cause in
humans and the environment are fairly well understood. Cancer, devel-
opmental effects, neurological effects, and effects on reproduction have
been associated with exposure (usually through fish consumption) of
humans and other animals to Great Waters pollutants. Though studies
relate these cancer and noncancer effects to specific Great Waters pol-
lutants, there are generally insufficient data available to prove the
linkage between atmospheric deposition of the pollutants and conse-
quent effects in humans and ecosystems.
Studies of relative loadings to waterbodies from atmospheric
deposition have demonstrated that atmospheric deposition can be a
significant contributor of toxic chemicals to the Great Waters. Studies
have demonstrated that, for example, atmospheric deposition is respon-
sible for as much as 77 to 89 percent of the loadings of PCBs to Lake
Superior and as much as 40 percent of the loadings of nitrogen to
Chesapeake Bay. Yet, the relative importance of atmospheric loading
for a specific chemical depends on the interaction of properties of the
chemical, weather patterns, and the kind and amount of airborne
sources and waterborne sources. Thus, even when data are available for
a particular chemical in a particular waterbody, only some of the data
can be generalized to other waterbodies or other chemicals.
Many sources and source categories of these pollutants have
been identified (see chart in Appendix E). However, because atmos-
pheric loadings to any particular waterbody are derived from local,
regional, and global sources, determining the particular sources
responsible for deposited pollutants is quite difficult. Further data are
needed for identification and characterization of the specific sources
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Chapter Four
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responsible for pollutants that are deposited to the Great Waters and,
thus, for the adverse effects of these pollutants on human health and
the environment. Whether or not effects from exposure to Great Waters
pollutants, such as those originating from long-range transport, are
sufficient to warrant regulatory action is a question for the risk man-
ager and has not been addressed here.
Further research is needed to better determine the full impacts
of these pollutants on human health and the environment and to
provide risk managers with sufficient information to ensure that deci-
sions result in pollution prevention and regulatory measures that will
yield significant benefits.
The following conclusions are based on the currently available
scientific data:
1. Persistence is a critical characteristic of the Great
Waters pollutants of concern. This characteristic allows
them to be transported long distances, to remain in the envi-
ronment for a significant period of time, and to accumulate
over time. Therefore, persistent chemicals can be deposited
and then reemitted and redeposited many times, resulting in
transport over long distances. Their accumulation in the envi-
ronment over time results in significantly greater exposure
potential than for chemicals that degrade in the environment.
2. The tendency to bioaccumulate is another critical
characteristic of pollutants of concern. This results in
potentially greater exposure for predators at the top of the
food web, such as eagles and humans. These pollutants are
stored in animal tissues and accumulate, which results in
biomagnification. That is, at each level of the food web an
animal accumulates the chemicals from its diet and passes
them along to the animal at the next level of the food web.
Top consumers in the food web may accumulate chemical
concentrations millions of tunes greater than that in the
water. For example:
• The cancer risk from eating 1 pound of Lake Ontario trout
is greater than the risk from drinking 20 lifetimes' worth
of water from Lake Ontario.75
• In the Great Lakes and Lake Champlain, fish consumption
advisories have been established for some fish because of
unsafe concentrations of chemicals, such as mercury, in
the fish. People who consume contaminated fish regularly
(such as Native Americans or subsistence fishermen) have
greater concentrations of the contaminants in their bodies
than other people. Humans generally are exposed to
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Chapter Four
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The USA is a signatory of the
Great Lakes Water Quality
Agreement, which requires that
the input of persistent toxic sub-
stances to the Great Lakes Basin
Ecosystem he "virtually elimi-
nated." In their Fifth Biennial
Report in 1989, the International
Joint Commission (IJC), an advi-
sory committee comprised of
representatives from the United
States and Canada, recom-
mended that the Parties (the
United States and Canada)
complete and implement imme-
diately a bmational toxic sub-
stances management strategy for
accomplishing, as soon as
possible,; the Great Lakes Water
Quality Agreement philosophy of
zero discharge. They concluded,
on the basis of mounting
evidence that "cannot be denied/'
that "there is a threat to the
health of our children emanating
from our exposure to persistent
toxic substances, even at very
low ambient levels." In their
Sixth Biennial Report in 1991,
the IJC concluded that "because
persistent toxic substances
remain in the environment for
long periods of time and become
widely dispersed, and because
they bioaccumulate in plants and
animals—including humans—
that make up the food web, the ,
ecosystem cannot assimilate
these substances." These toxic
substances, the IJC concluded,
"are too dangerous to the
biosphere to permit their release
in any quantity."
mercury through ingestion of fish and, in the United
States, 1 percent of the population has an average daily
intake of methylmercury (the most toxic form of mercury)
higher than the World Health Organization's suggested
"safe level."
• Breast-fed babies are considered to be one level in the food
web higher than their mothers. After 6 to 9 months of
breast-feeding, the concentration of PCBs in a baby can
reach four times that in the mother.76
3. Significant adverse effects on human health and wild-
life have been observed due to exposure, especially through
fish consumption, to persistent pollutants that bioaccumulate.
These adverse effects range from immune system disease and
reproductive problems in wildlife to subtle developmental and
neurological impacts on children and fetuses. Often considered
to be unrelated, the human and wildlife effects of these chemi-
cals are essentially linked. As EPA's Science Advisory Board
pointed out, "most human activities that pose significant
ecological risks . . . pose direct or indirect human health risks
as well."12
Although research is continuing, the International Joint Com-
mission considered the known effects sufficient reason to adopt
a goal of "virtual elimination" of persistent organic chemical
releases to the Great Lakes (see sidebar).
4. Noncancer effects are a significant human health con-
cern. Most of the chemicals of concern are probable human
carcinogens, exposure to which is expected to increase the
population incidence of cancer. However, noncancer effects will
impact some members of a population exposed to levels that
exceed a threshold level. Many of the pollutants of concern are
developmental toxicants capable of altering the formation and
function of critical body systems and organs. Therefore, the
developing embryo and fetus and breast-fed infants are
particularly sensitive to these chemicals.
Subtle changes in thought processing and activity levels were
observed in one study of children of women who consumed
Lake Michigan fish two to three times a month. The ultimate
impact of individual impairments such as these can be charac-
terized as a "diminishment of potential" in humans. Exposure
to the mother may have been a single large exposure, small
cumulative exposures, or long-discontinued exposure and may
have caused no visible symptoms in the mother.
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Chapter Four
Conclusions and Recommendations
5. Ecological effects are significant and can be subtle, such
as immune function impairment, reproductive problems, and
neurological changes that affect survival. Also, these impacts
can affect the offspring of the exposed individual and may not
be evident until later in life. For example, a study of tern eggs
and chicks, contaminated through maternal exposure to PCBs
and dioxins, showed a 35 percent mortality rate due to "wast-
ing." The deaths in one study occurred after 17 days, and, in
the followup study, the same percentage died after 31 days.
Such delayed effects and subtle symptoms can easily be over-
looked.
Other ecological effects are quite obvious and can affect sur-
vival of individuals and/or populations. For example, crossed
bills, associated with exposure of birds to toxic pollutants, can
hinder adequate feeding.
6. There have been many exceedances of existing water
quality criteria and standards as well as of the proposed
Great Lakes Water Quality Criteria (pGLWQC) (see Appendix
B). Persistence allows accumulation of a chemical to undesir-
able levels. The pGLWQCs are particularly important
measures of the health of aquatic resources because they incor-
porate bioaccumulation factors.
7. Eutrophication, caused by excess nitrogen inputs, is a
major problem in TJ.S. coastal waters, and, in studied
estuaries, the atmospheric contribution to the total nitrogen
loading is significant. Nitrogen is the limiting nutrient in most
coastal estuaries. Thus, addition of nitrogen in a form usable
by plants results in accelerated eutrophication of the
waterbody, to the point of causing toxic effects—characterized
by additional plant growth, usually of algae, which shades
beneficial plants and uses up oxygen during decay. Eutrophica-
tion causes ecological effects and economic impacts that range
from nuisance algal blooms to oxygen depletion and fish kills.
In studies of the Chesapeake and Delaware Bays, the atmos-
phere was estimated to account for 28 to 40 percent of the
total nitrogen loading, which contributes to system-wide
eutrophication.
8. Case studies have shown atmospheric deposition to be
a major contributor of mercury, POMs, PCBs, and nitrogen.
Available estimates of relative loadings for studied waters and
specific chemicals are listed in Tables 7 and 8, page 55.
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Chapter Four
Conclusions and Recommendations
The relative significance of atmospheric loadings for any
specific waterbody is dependent on the amount of waterborne
loading to which it is being compared. The absolute quan-
tity of atmospheric loadings also warrants attention,
especially since loadings of even small amounts of pollutants
that bioaccumulate can result in a significant pollutant
burden in fish and, ultimately, in humans.
9. Airborne emissions from local as well as distant
sources contribute to pollutant loadings, through atmos-
pheric deposition, to waters. Transport distances depend on
the characteristics of the chemicals and source emissions as
well as weather patterns. While the contribution of distant air
pollution sources to remote pristine regions, such as the
Arctic, is well documented, more data are needed to deter-
mine sources and source locations affecting the Great Waters.
10. Continued research is needed, especially to help deter-
mine atmospheric contributions, to identify sources, to evalu-
ate low-exposure effects, and to target HAPs that pose the
most significant risk to human health and aquatic resources.
Conclusions could not be drawn for two areas of concern because
of the lack of data. Available data are not sufficient to quantify the
overall relative atmospheric loadings (for all of the Great Waters for all
of the HAPs). Therefore, relative loading estimates are, and will
continue to be, chemical- and waterbody-specific. Neither is it possible
to identify the specific sources or source types emitting the pollutants
into the atmosphere that are ultimately deposited to the Great Waters
(except in localized case studies).
Recommendations and Actions
The goal of section 112(m) of the Clean Air Act, as amended in
1990, as discussed earlier, is to determine if atmospheric inputs of
pollutants, and the impacts from these atmospheric inputs to the Great
Waters, warrant further reductions of atmospheric releases. If reduc-
tions are warranted, a strategy to reduce atmospheric releases of the
pollutants must be devised. In making the following recommendations,
EPA evaluated the available scientific information and called upon the
expertise of its own, as well as outside, scientists. Most important,
EPA considered the implications of action and of inaction, while also
recognizing that section 112(m) of the 1990 Amendments mandates
a preventive approach, stating that EPA should act to "prevent"
adverse effects and to "assure protection of human health and the
environment."
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Chapter Four
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In the 1992 amendments to the
Chesapeake Bay Agreement, the
Governors of Virginia, Maryland,
and Pennsylvania; the Mayor of
the District of Columbia; the
EPA Administrator; and the
Chesapeake Bay Commission
chair committed "to incorporate,
into the Nutrient Reduction
Strategies, an air deposition
component which builds upon the
1990 Amendments to the Federal
Clean Air Act and explores addi-
tional implementation opportuni-
ties to further reduce airborne
sources of nitrogen entering
Chesapeake Bay and its tribu-
taries."
EPA's recommendation is that reasonable actions are
justified, based on evaluation of the scientific information cur-
rently available, and should now be taken and that research
should continue. NOAA concurs with the principles of this
policy.
Although there are significant uncertainties in the information
available, there is enough convincing evidence to prompt action. Effects
documented for some toxic, persistent, bioaccumulative pollutants are of
concern in the Great Lakes, at least, and have prompted strong state-
ments from the International Joint Commission. Similarly, impacts from
nitrogen loading to Chesapeake Bay led the Chesapeake Executive
Council to address air sources in the development of tributary basin
nutrient reduction strategies (see sidebar).
"If we wait until we have all of the answers to act," many argue,
it will be too late to fix the problem. In addition, some argue that fur-
ther contributions of persistent bioaccumulatable pollutants add to an
environmental burden that is already causing effects. EPA believes it is
important to balance our present understanding of atmospheric deposi-
tion 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 take whatever regulatory actions
are appropriate in the most cost-effective way possible. Also, EPA must
target that research that is necessary to define the necessary actions.
(EPA's research needs and plans are discussed in Appendix G.)
Specifically, EPA is recommending a series of actions. Because of
the uncertainties, the actions EPA proposes are not specific to sources
but, rather, are targeted for those chemicals about which there is evi-
dence of potentially significant health and environmental risks. The
recommended actions are focused especially on utilizing regulatory
mechanisms in the Clean Air Act that address the most hazardous
chemicals. EPA believes that the characteristics of toxicity, persistence,
and the tendency to bioaccumulate, along with exposure and the signifi-
cance of adverse effects, warrant special treatment for the Great Waters
chemicals of concern, such as outlined below. EPA also believes that this
treatment is consistent with the congressional intent for those regula-
tory mechanisms and for section 112(m).
The recommended actions also promote an integrated effort to
assess the problem and reduce pollution. EPA recognizes that pollutants
are transferred continuously between air, water, and land and that,
to adequately address pollution problems, multimedia, multiagency
approaches must be explored. The recommendations reflect an inte-
grated effort, and plans for future Great Waters program activities
reflect increased integration within and outside the Agency.
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Chapter Four
Conclusions and Recommendations
EPA continues to recommend pollution prevention as the best
option for reducing or eliminating the input of these chemicals to the
environment and advocates the voluntary reduction of any HAPs.
Consistent with the above, the recommendations for action, out-
lined below, are divided into three strategic themes.
Strategic Themes and Actions
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.
Action Items
a.
b.
c.
EPA is developing standards under section 112(d) for
approximately 35 source categories of Great Waters 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.
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.
As soon as practicable, EPA will publish an advance notice
of proposed rulemaking to notify the public of EPA's inter-
est in establishing lesser-quantity emission rates (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.
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Chapter Four
Conclusions and Recommendations
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 develop-
ment in accordance with section 112(k).
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.
f. EPA will conduct a pilot project examining the use of Great
Waters impacts analyses in the development of section
112(d) standards.
g. For Great Waters HAPs, EPA is proposing a cap (i.e., 0.01
ton/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 pro-
cesses. 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.
h. EPA plans to propose a revised municipal waste combustor
rule, with stringent controls on mercury emissions and
emissions of other Great Waters HAPs, not later than
summer 1994.
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 envi-
ronmental 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 develop-
ment of strategies for reducing environmental exposures to
Great Waters pollutants.
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Chapter Four
Conclusions and Recommendations
k.
EPA is developing ecological effects assessment screening
methods for reviewing petitions to add and delete pollut-
ants from the HAP list and to delete source categories from
the source category list. EPA will consider the Bioaccumu-
lation Factor Methodology (58 FR 20802) in the develop-
ment 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.
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 FR 20802) and which have been identified as having
potentially significant air sources, should be added to the
list of Great Waters pollutants of concern.
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.
m. In the development of regulations and pollution prevention
or reduction strategies under the 1990 Amendments, EPA
will examine the potential for reductions of oxides of nitro-
gen and will determine how additional NOX reductions can
be achieved for protection of coastal water quality and
related resources.
n. EPA will develop Achievable Control Technology docu-
ments (ACTs) for NOX. This is expected to result in nation-
wide NOX emissions reductions, thus protecting coastal
waters, as States develop regulations under the National
Ambient Air Quality Standards program.
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Chapter Four
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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.
Action Items
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 this report
or to take a lead role in the implementation of specific
recommendations.
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 impair-
ment. 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 effec-
tive 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 environmen-
tal 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.
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.117
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Chapter Four
Conclusions and Recommendations
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.
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 emis-
sions of pesticides of known and potential concern, includ-
ing banned pesticides.
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 under way:
• A "Virtual Elimination Pilot Project" is under way in
the Great Lakes Basin, as a part of a comprehensive
toxics reduction effort. The Virtual Elimination Pilot
Project proposes selecting a small group of toxics as a
pilot and performing an in-depth analysis of oppor-
tunities for reduction from all sources.
• 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.
• 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.
g. EPA will continue its work with Canada, under the Great
Lakes Water Quality Agreement, on airborne toxic sub-
stances. These continuing bilateral efforts are assisting and
will continue to assist in meeting Great Water program
objectives during the 1990s.
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Chapter Four
Conclusions and Recommendations
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 envi-
ronmental exposure to Great Waters HAPs.
i. EPA will initiate discussions about possible mechanisms
that Kegional 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 pollut-
ants 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).
Action Items
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 the EPA 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 deter-
mining 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 prob-
lematic if emissions continue. Included in the strategy will
be an assessment of the need for development of took 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.
b. EPA will continue to work with NOAA to pursue the devel-
opment 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.
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Chapter Four
Conclusions and Recommendations
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 communi-
ties and affirmed by the Great Waters Core Project
Management Group.
• 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 (a group of
six of the Great Waters pollutants), and will identify
categories of sources of the specific pollutants listed
in section 112(c)(6).
• EPA will continue source characterization and
identification activities.
• 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.
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.
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'"'"'"~"™'
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Chapter Five
References
i.
2.
3.
4.
5.
6.
7.
C.P. Rice and M.S. Evans, Toxaphene in the Great Lakes, in Toxic
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(New York, NY: John Wiley, 1984), 163-194.
R.A. Rapaport, N.R. Urban, P.D. Capel, J.E. Baker, B.B. Looney,
S.J. Eisenreich, and E. Gorham, "New" DDT inputs to North America:
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R.A. Rapaport and S.J. Eisenreich, Historical atmospheric inputs of high
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J.E. Baker, T.M. Church, S.J. Eisenreich, W.F. Fitzgerald, and J.R.
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Nitrogen to the Great Waters, prepared for Office of Air Quality Planning
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Triangle Park, NC, 1993.
G.J. Keeler, J. Pacyna, T. Bidleman, and J. Nriagu, Identification of
Sources Contributing to the Contamination of the Great Waters by Toxic
Compounds, prepared for Office of Air Quality Planning and Standards,
U.S. Environmental Protection Agency, Research Triangle Park, NC
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W. Swain, T. Colborn, C. Bason, R. Howarth, L. Lamey, B. Palmer, and
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9. R. Arimoto, Atmospheric deposition of chemical contaminants to the
Great Lakes, J. Great Lakes Res. 15, no. 2 (1989):339-356.
10. D.W. Harkins and R.E. Swain, Papers on smelter smoke, 1: The determi-
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study of the effects of high stacks and large condensing flues, Journal of
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and Strategies for Environmental Protection, Science Advisory Board,
Washington, DC (SAB-EC-90-021), 1990.
13. U.S. Environmental Protection Agency, A Report to Congress on the
Great Lakes Ecosystem, Great Lakes National Program Office, Chicago,
IL, 1992 (draft).
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17. Agency for Toxic Substances and Disease Registry, Toxicological Profile
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Agency for Toxic Substances and Disease Registry, Toxicological Profile
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Agency for Toxic Substances and Disease Registry, Toxicological Profile
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Agency for Toxic Substances and Disease Registry, Toxicological Profile
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U.S. Environmental Protection Agency, Fact sheets of various pesticide
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32. Environment Canada, Toxic Chemicals in the Great Lakes and Associ-
ated Effects: Synopsis, Department of Fisheries and Oceans, Health and
Welfare Canada, Toronto, Ontario, 1991.
33. Telephone conversation with Maryland Department of Health,
March 16, 1993, Information on fishing consumption advisories in the
Chesapeake Bay.
34. Facsimile, from Dr. Khizai Wasti to Virginia Department of Health,
Bureau of Toxic Substances, Richmond, VA, March 16, 1993, Fishing
restrictions and health advisories in effect for Virginia Eivers,
Richmond, VA.
35. Telephone conversation with Mike Gaits, Vermont Department of
Health, Environmental Health Division, April 14, 1993, Information
on fishing consumption advisories in Lake Champlain.
36. Telephone conversation with Marie Zuroske, Thurston County Health
Department, April 13, 1993, Information on fishing consumption
advisory in Budd Inlet.
37. Telephone conversation with Tony Bossart, Kings County Health
Department, April 12, 1993, Information on fishing consumption
advisory in Duwamish River.
38. Environment Canada, Toxic Chemicals in the Great Lakes and Associ-
ated Effects: Volume II—Effects, Department of Fisheries and Oceans,
Health and Welfare Canada, Toronto, Ontario, 1991.
39. Chesapeake Bay Program, Chesapeake Bay Water Column Contaminant
Concentrations: Critical Issues Forum, Annapolis, Maryland, 1993.
40. U.S. Environmental Protection Agency, Strategies, Goals, and Environ-
mental Results: EPA's Environmental Progress Report, Office of Policy,
Planning, and Evaluation, Washington, DC, 1992 (draft).
41. H.E. Hicks, Ph.D., and L.S. Katz, Ph.D., Impact on Public Health of
Persistent Toxic Substances in the Great Lakes Region, U.S. Department
of Health and Human Services, Public Health Service, Agency for Toxic
Substances and Disease Registry, Division of Toxicology, March 1992
(draft), and works cited therein.
42. U.S. Environmental Protection Agency, Consumption Surveys for Fish
and Shellfish: A Review and Analysis of Survey Methods, Office of
Water, Washington, DC (WH-585), February 1992.
43. Clean Water Fund of Michigan, If It's Broke, Fix It: Why Michigan's
Environmental Health Agencies Must Make Changes to Help Detroiters
and Others Fish Without Fear, January 1993.
86
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44. N.C. Department of Environmental Health and Natural Resources,
NC Lake Assessment Report, Department of Environmental Manage-
ment, Raleigh, NC (Report No. 92-02), June 1992.
45. U.S. Environmental Protection Agency, National Water Quality Inven-
tory: 1990 Report to Congress, Office of Water, Washington, DC
(EPA 503/9-92-006), 1992.
46. Harold Humphrey (ed.), Editors note: Environmental contaminants &
reproductive outcomes, Health & Environment Digest 5, no. 8 (1991).
47. J. L. Jacobson and S. W. Jacobson, A 4-year followup study of children
born to consumers of Lake Michigan fish, J. Great Lakes Res. 19, no. 4
(1993):776-783.
48. U.S. Environmental Protection Agency, Health Effects Assessment
Summary Tables, Office of Health and Environmental Assessment,
Environmental Assessment and Criteria Office, Cincinnati, OH, for the
Office of Solid Waste and Emergency Response, Office of Emergency and
Remedial Response, Washington, DC [OERR 9200.6-303(91-1)], 1991.
49. U.S. Environmental Protection Agency, Integrated Risk Information
System (IRIS), Online, Office of Research and Development, Office of
Health and Environmental Assessment, Environmental Criteria and
Assessment Office, Cincinnati, OH, 1993.
50. U.S. Environmental Protection Agency, Health Effects Assessment for
Chlordane, Environmental Criteria and Assessment Office, Cincinnati,
OH (ECAO-CIN-H023a), 1988.
51. U.S. Environmental Protection Agency, Health Effects Assessment for
DDT, Environmental Criteria and Assessment Office, Cincinnati, OH
(ECAO-CIN-H026a), 1988.
52. U.S. Environmental Protection Agency, Health Effects Assessment for
Dieldrin, Environmental Criteria and Assessment Office, Cincinnati, OH
(EPA/600/8-88/030), 1987.
53. U.S. Environmental Protection Agency, Health Effects Assessment for
Toxaphene, Environmental Criteria and Assessment Office, Cincinnati,
OH (EPA/600/8-88/056), 1987.
54. U.S. Environmental Protection Agency, Reportable Quantity Document
for Lead, Environmental Criteria and Assessment Office, Cincinnati, OH
(ECAO-CIN-R134A), 1990.
55. Agency for Toxic Substances and Disease Registry, Toxicological Profile
for Polycyclic Aromatic Hydrocarbons, U.S. Department of Health and
Human Services, U.S. Public Health Service, Washington, DC, 1990.
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56. M.A. Gallo, R.J. Scheduplein, and R.A. Van Der Heijden, eds., Biolog-
ical Basis for Risk Assessment ofDioxins and Related Compounds
(Banbury Report No. 35), Cold Spring Harbor Laboratory Press, 1991.
57. U.S. Environmental Protection Agency, Drinking Water Regulations and
Health Advisories, Office of Water, Washington, DC, 1992.
58. U.S. Environmental Protection Agency, EPA Quality Criteria for Water
1986, Washington, DC (EPA 440/5-86-001), 1986.
59. International Joint Commission, Great Lakes Water Quality Agreement
of 1978, Windsor, Ontario, 1978, as cited in Reference 31.
60. Personal communication, H. Garabedian, State of Vermont, Department
of Environmental Conservation, Waterbury, VT, Unpublished data
(provided in 1993).
61. T. Colborn, F.S. vom Saal, and A.M. Soto, Developmental effects of
endocrine-disrupting chemicals in wildlife and humans, Environ. Health
Perspectives 101 (1993):378-384.
62. D.L. Davis, H.L. Bradow, M. Wolff, T. Woodruff, D.G. Hoel, and
H. Anton-Culver, Medical hypothesis: Xenoestrogens as preventable
causes of breast cancer, Environ. Health Perspectives 101 (1993):372-377.
63. W.F. Fitzgerald and T.W. Clarkson, Mercury and monomethylmercury:
Present and future concerns, Environ. Health Perspectives 96 (1991):
159-166.
64. U.S. Environmental Protection Agency, Tribes at Risk: The Wisconsin
Tribes Comparative Risk Project, Region 5, Policy, Planning, and Evalua-
tion, Chicago, IL (EPA 230-R-92-017), 1992.
65. Chesapeake Executive Council, Chesapeake Bay Agreement - 1992
Amendments, Annapolis, MD, 1992.
66. J. Burke, G.J. Keeler, and T. Scherbatskoy. An investigation of atmo-
spheric mercury in the Lake Champlain Basin, in Proceedings: Interna-
tional Conference on Heavy Metals in the Environment, Toronto, Canada,
September 1993.
67. M. Hoyer, J. Burke, L. Cleckner, K. Mukherjee, G.J. Keeler. Mercury in
precipitation: A multi-site study in Michigan, in Proceedings: Interna-
tional Conference on Heavy Metals in the Environment, Toronto, Canada,
September 1993.
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68. G.J. Keeler, M.E. Hoyer, and C. Lamborg, Atmospheric mercury
measurements in the Great Lakes Basin: Methods comparisons and
recent findings, in eds., J. Huckabee, and C. Watrous, Mercury as a
Global Pollutant-Toward Integration and Synthesis, Boca Raton, FL,
Lewis Publishers, 1993.
69. G.J. Keeler, Lake Michigan Urban Air Toxics Study, Atmospheric Re-
search and Exposure Assessment Laboratory, Office of Research and
Development, U.S. Environmental Protection Agency, Research Triangle
Park, NC, 1994.
70. D.A. Wolfe, R. Monhahan, P.E. Stacey, D.R.G. Farrow, and A. Robertson,
Environmental quality of Long Island Sound: Assessment and manage-
ment issues, Estuaries 14 (1991).
71. U.S. Environmental Protection Agency, Documentation for Developing
the Initial Source Category List: Final Report, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, 1992.
72. Radian Corporation, Locating and Estimating Air Emissions from
Sources ofDioxins and Furans, Prepared for the Emission Inventory
Branch of U.S. Environmental Protection Agency, Research Triangle
Park, NC, 1993 (draft).
73. U.S. Environmental Protection Agency, National Air Pollutant Emission
Trends, 1900-1992, Office of Air Quality Planning and Standards,
Research Triangle Park, NC (EPA-454/R-93-032), 1993.
74. U.S. Environmental Protection Agency, National Emissions Inventory of
Mercury and Mercury Compounds: Interim Final Report (EPA-453/R-93-
048), 1993.
75. Lake Ontario Secretariat, Lake Ontario Toxics Management Plan,
1993 Update, Volume I, 1993.
76. Great Lakes Science Advisory Board, 1991 Report to the International
Joint Commission, Ontario, Canada, 1991.
77. Report of the National Performance Review: Creating a Government
That Works Better and Costs Less, Washington, DC, September 1993,
page 139.
78. R.J.J. Stevens and M.A. Neilson, Inter- and intra-lake distributions
of trace organic contaminants in surface waters of the Great Lakes,
Journal of Great Lakes Research 15 (1989):377-393.
79. Personal communication, D. DeVault, U.S. Environmental Protection
Agency, Great Lakes National Program Office, Chicago, IL, Unpublished
data (provided in 1993).
89
-------
/.»•** -^ * "-.
:»*** ;;X!€
-------
Appendices
Appendices
Appendix A: Lists of Bioaccumulative Chemicals of Concern and
Potential Bioaccumulative Chemicals of Concern
Appendix B: Comparison of Great Lakes Sampling Data
to Various Water Quality Benchmarks
Appendix C: Historical EPA Regulations
Appendix D: Summary of Clean Air Act Section 112 Activities
Appendix E: Progress Under Section 112(m)
Appendix F: Summary of MACT Source Categories Potentially
Emitting Great Waters Pollutants of Concern
Appendix G: Preliminary Summary of Research
and Program Planning
-------
-------
Appendix A
Appendix A
Bioaccumulative Chemicals of Concern
Potential Bioaccumulative Chemicals of Concern
Aldrin
4-Bromophenyl phenyl ether
Chlordane
4,4-DDD; p,p-DDD; 4,4-TDE; p,p-TDE
4,4-DDE; p,p-DDE
4,4-DDT; p,p-DDT
Dieldrin
Endrin
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorobutadiene; hexachloro-l,3-butadiene
Hexachlorocyclohexane; BHC
a-Hexachlorocyclohexane; a-BHC
p-Hexachlorocyclohexane; P-BHC
8-Hexachlorocyclohexane; 5-BHC
Lindane; y-BHC; y-hexachlorocydohexane
Mercury
Methoxychlor
Mirex; dechlorane
Octachlorostyrene
PCBs; polychlorinated biphenyls
Pentachlorobenzene
Photomirex
2,3,7,8-TCDD; dioxin
1,2,3,4-Tetrachlorobenzene
1,2,4,5-Tetrachlorobenzene
Toxaphene
Benzo[a]pyrene; 3,4-benzopyrene
3,4-Benzofluoranthene; benzo[6]fluoranthene
11,12-Benzofluoranthene; benzo[&]fluoranthene
1,12-Benzoperylene; benzo^ijperylene
4-Chlorophenyl phenyl ether
l,2:5,6-Dibenzanthracene; dibenz[a,/i]anthracene
Dibutyl phthalate; di-n-butyl phthalate
Indeno[l,2,3-cd]pyrene; 2,3-o-phenylene pyrene
Phenol
Toluene; methylbenzene
Source: U.S. Environmental Protection Agency, Proposed water quality guidance for the Great Lakes system: Proposed rule
and correction, Federal Register 58:20802-21047, April 16, 1993.
A-l
-------
-------
Appendix B
Appendix B:
Comparison of Great Lakes Sampling Data
to Various Water Quality Benchmarks (in ppb)
B-l
-------
Appendix B
Comparison of Great Lakes Sampling Data to Various Water Quality Benchmarks (ppb)
1 1
.Pollutant
Cadmium
Chlordane
DDT/DDE
Dieldrin
Hexachlorobenzene
a-HCH
Lindane
Lead
Mercury
PCBs
Benzo(a)pyrene
(indicator of POM)
2,3,7,8-TCDP
2,3,7,8-TCDD
Toxaphene
National
AWQC:
Fresh Water
Aquatic Lifea
1.1
0.0043
0.001f
0.0019
—
—
0.08
3.2
0.012
0.014
—
—
0.00001
0.0002
National
AWQC:
Human
Health*
10
0.0046
0.00024f
0.00071
0.0072
0.092
0.186
50
0.144
0.00079
0.028h
—
0.00000013
0.0071
Proposed ;
Great Lakes
Water Quality
Criteria*1
0.78
0.0002
0.00000087
0.0001
0.0001
—
0.7
—
0.00018
0.000017
—
—
0.0000000096
0.00002
'"..•• Great Lakes
Water Quality
Agreement
Objectives'1
0.2
0.06
0.003
0.001g
—
—
0.01
10-25
0.2
—
—
—
0.008
a Values listed are for fresh water chrome criteria except for 2,3,7,8-TCDD, which is the fresh water chronic lowest observed effects level
(LOEL). Values for cadmium and lead are hardness dependent (based on 100 mg/L CaC03).
b Values listed are for human chronic exposure through both fish consumption and drinking water; values for potential carcinogens
correspond to a 10"5 individual cancer risk level.58
c Values listed are the most stringent (i.e., lowest) among those proposed for protection of human health, aquatic life, or wildlife;
values for potential carcinogens correspond to a 10"5 individual cancer risk level. Value for cadmium is hardness dependent
(based on 50 mg/L CaC03).59
d Values listed are for protection of the most sensitive user of the water among humans, aquatic life, or wildlife. '
c Concentrations are the maximum post-1980 open water sampling values reported in Eeferences 31, 78, and 79 (sampling data are
for 1980-1986). Values in bold indicate exceedance of at least one criterion. Sources of data are as follows: a = Reference 78;
b = Strachan and Eisenreich 1988, as cited in Reference 31; c = Rossman 1984 and 1986, as cited in Reference 31; d = Reference 79.
f Value for DDT only.
8 Value for aldrin/dieldrin combined.
hValue for polycyclic aromatic hydrocarbons.
' Measured water concentrations were beneath detection levels.
B-2
-------
Appendix B
Maximum Open Water Concentrations6
Erie
0.32°
0.0001a
0.000096a
O.OOll3
0.00026a
0.0065a
0.0025a
3°
0.14°
0.0035a
0.0003b
nd1
nd1
nd1
Huron
0.061°
0.00007a
0.000046a
0.000693
0.000073a
0.011a
0.0014a
O.llc
0.35°
0.0023a
0.0001b
nd1
nd1
nd1
Michigan
0.087C
no data
0.0002b
0.0003b
0.00006b
0.01b
0.0007b
0.48b
O.llb
0.002b
0.001b
nd1
nd1
nd1
Ontario
0.12b
X0000743
0.000143 i
0.000513
0.00011a
0.0059a
0.0023a
0.4b
0.025b
0.00263
0.0003b
nd1
nd1
nd1
Superior
0.044°
0.0006a
ot detected
0.00043a
0.00004a
0.011a
0.0014a
0.13°
0.12b
0.00058a
0.0001b
iid1
nd1
nd;
B-3
-------
-------
Appendix C
Appendix C
Historical EPA Regulations
Authority
Clean Air Act
(1970 - present)
C*4- -t-!
stationary
Sources
Clean Air Act
(1970 - present)
Mobile Sources
Federal
Insecticide,
Fungicide, and
Rodenticide
Act (FIFRA)
(1972 - present)
Toxic
Substances
Control Act
(1976 - present)
Superfund Amend-
ments and Reau-
thorization Act
(1976 - present)
Action
National Ambient Air
Quality Standards for
Criteria Pollutants
National Emission
Standards for
Hazardous Air
Pollutants
Emissions Controls
Emergency Planning
and Community
light-to-Know
EPCRA)
GW Pollutants
Controlled
Lead, Particulate Matter,a
Nitrogen Oxides
Mercury
Nitrogen Oxides,
Particulate Matter,
Lead
Mercury, Chlordane,
DDT/DDE, Hexachloro-
benzene, Lindane,
Toxaphene
PCBs
All except nitrogen
compounds, dieldrin, DDT/
DDE, 2,3,7,8-TCDD,
2,3,7,8-TCDF, and some
POM.b
Notes
These "health-based" standards established safe concen-
tration levels of six criteria pollutants, three of which are
not currently of concern to the Great Waters. States are
responsible for implementing regulations to keep the
levels of air pollution below these concentrations and
are provided guidance by the EPA. States must submit
plans to EPA for how areas will meet these standards.
Guidance to States includes an identification of alternative
control techniques for sources in various industries includ-
ing incinerators, smelters, electric utilities, cement plants,
and wood stoves.
These standards set emission limits for various hazardous
air pollutants. Mercury emissions from ore processing
facilities, mercury cell chlor-alkali plants, and sludge
drying plants were regulated.
The Clean Air Act required reductions in emissions from
auto exhaust, set more stringent fuel economy standards,
and required inspection and maintenance (KM) programs
to locate malfunctioning emission control systems. Since
1970, lead emissions from automobiles have been reduced
by approximately 90%.
The 1990 Amendments require lower tailpipe standards;
more stringent emissions testing procedures; expanded
I/M programs; new vehicle technologies; introduction of a
range of clean fuels programs; clean transportation provi-
sions; and possible regulation of emissions from nonroad
vehicles.
This Act provides the authority for banning and restrict-
ing the use of pesticides containing these chemicals in
the U.S. according to how and where they are used.
It requires registration of all pesticides and reporting
of any exported pesticides.
In addition to other requirements, this Act bans the
manufacture, processing, distribution in commerce, and
use of PCBs except in totally closed systems and estab-
lishes rules for disposal of PCBs.
Establishes new authorities for emergency planning and
preparedness, community right-to-know reporting, and
toxic chemical release reporting.
UP °f a
°f substances ^ mav Mudfl the
pollutants of concern:
Reporting of releases of these pollutants is not currently required, mainly due to their low emissions. EPA is taking comment on modi-
fications to EPCRA 313 requirements, such as lowering the reporting thresholds to ensure that release and transfer information is
obtained for certain persistent pollutants. (See proposed rule: 59 FR 1788, January 12, 1994.)
Note: This table documents EPA legislation that has reduced emissions of Great Waters pollutants directly into the air
It does not account for other legislation that may have reduced these pollutants from other sources that may eventually C-l
be emitted to the air. Other such sources may include effluent released to waterbodies and runoff from agriculture
-------
-------
Appendix D
Appendix D
Summary of Clean Air Act Section 112 Activities?
Subsection
112(c)(6)
112(d)
112(g)
112(0
112(j)
112(k)
112(m)
112(n)(l)(A)
112(n)(l)(B)
Affected Pollutant
Lead compounds, Hexachlorobenzene,
Mercury, FOB, 2,3,7,8-TCDF,
2,3,7,8-TCDD, POM
All GW pollutants except nitrogen compounds
All GW pollutants except nitrogen compounds
All GW pollutants except nitrogen compounds
All GW pollutants except nitrogen compounds
Not yet determined
All GW pollutants
Potentially: Mercury, Cadmium,
Lead, POM, TCDF, TCDD
Mercury
Year
Due
2000
1991-2000
1992
Beginning
in 2001
1994
1999
1993
and every
2 years
thereafter
1995
1994
, - Comments
Eequires regulations for "sources accounting for 90%
of the aggregate emissions of each such pollutant."
Requires regulations for all sources emitting 10 tons
of any one hazardous air pollutantb or 25 tons total.
These sources must have "maximum achievable control
technology" (MACT). Smaller sources can be regulated
in certain cases.
Requires MACT for new or modified sources.
Evaluation of remaining health risk (residual risk)
to public after application of the Section 112 standards.
Additional standards to reduce residual risk.
If any Section 112 standard is not promulgated in
accordance with the schedule,0 the individual
sources become responsible for controlling their
emissions subject to State approval.
90% of emissions of 30 hazardous air pollutants that
pose the greatest threat to public health must be
regulated.
Reports to Congress due on the status of the Great
Waters program including regulatory recommendations.
A report to Congress to assess the need for further
regulation on this industry.
A report to Congress will document the health and
environmental effects of mercury emissions and the
technologies available to control them.
aUnder section 112(m), the Clean Air Act, as amended in 1990, requires a determination of whether the other provisions of this section
are adequate to prevent serious adverse effects to public health and serious or widespread environmental effects. This table is designed
to alert the reader to other pertinent activities that affect Great Waters pollutants. Nitrogen compounds are not addressed under Title
III of the 1990 Clean Air Act, but they are addressed under Titles I, II, and IV.
bSection 112 of the Clean Air Act, as amended in 1990, contains a list of 189 hazardous air pollutants.
c National Emission Standards for Hazardous Air Pollutants Schedule for the Promulgation of Emission Standards under section 112(e)
of the Clean Air Act Amendments of 1990 (58 FR 63941, December 3, 1993).
D-l
-------
-------
Appendix E
Appendix E
Progress Under Section 112 (m)
Section 112(m), "the Great Waters program," was written into
the Clean Air Act, as amended in 1990, to complement existing
programs working to address water quality problems in the Great
Lakes and other waterbodies. In fact, the requirements are similar to
Annex 15 of the Great Lakes Water Quality Agreement, which the EPA
is working to fulfill.
The EPA began planning for the Great Waters program during
the summer of 1990. Since then, a great deal of work has taken place
through the cooperation of many EPA program offices, laboratories, and
regional offices. Other agencies participating actively in the Great
Waters program are the National Oceanic and Atmospheric Adminis-
tration (NOAA) and the appropriate States.
Below is a summary of the activities that have been undertaken
by the Agency and the progress on specific monitoring requirements.
There is also related work taking place by non-Federal parties, such
as emission inventory efforts by State agencies, which will not be
addressed in detail here. However, EPA is working closely with the
State agencies, and is leveraging their efforts whenever possible and
appropriate. These complementary State efforts are necessary to the
accomplishment of the goals of the Great Waters program.
Progress by EPA
Development of a screening level literature review, providing an assess-
ment of what kind and amount of information is available on the issue
of atmospheric deposition of hazardous air pollutants (HAPs) to aquatic
ecosystems
Development of an assessment of the 1990 Amendments list of 189
HAPs to determine which are most likely to be problematic when
deposited into aquatic systems
Intra-agency leveraging of relevant activities, including:
- Lake Michigan Urban Air Toxics Study
— Great Lakes deposition estimates for Lake Michigan
- Metals monitoring in Chesapeake Bay area (with NOAA)
- NOX deposition modeling in Chesapeake Bay
- Modification and extension of Chesapeake Bay Atmospheric
Deposition Study
E-l
-------
Appendix E
- Sample analysis for Integrated Atmospheric Deposition Study,
a U.S./Canadian cooperative network
- Great Lakes regional toxics emission inventory (with the Great
Lakes Commission/States)
- Compilation of available emission inventory data on a
national scale.
Analysis of existing ambient air metals samples for Gulf of Mexico
States
Conduct of a scoping level mass-balance for nitrogen for Gulf of Mexico
Preparation of three support documents by technical experts to address
the three main scientific questions defined in Section 112(m) of the
Clean Air Act: relative loading, effects, and source identification
Sponsorship of a major workshop for peer review of support documents
Production of a descriptive brochure of the Great Waters program
and the waterbodies included
Development of a research planning guidance document
Preparation of a national screening level emission inventory for
the specific pollutants in Section 112(c)(6)
Prototype long-range mercury transport modeling
Prototype indirect mercury exposure modeling
Development of a screening level atmospheric loading assessment for
Galveston Bay, using a suite of chemicals and a method to complement
work in Chesapeake Bay
Assessment of over-water versus onshore siting for samplers
Assessment of urban contribution to atmospheric loading
Deposition sampling for loading assessments
Development (with Great Lake States) of Lakewide Management Plans
(LaMPs), first for Lake Michigan, that have a requirement for assess-
ment of pollutant loading and planning for elimination of water quality
effects. Some relevant activities under this program are:
- Development of a mass balance for PCBs in Green Bay
- Lake Michigan Urban Air Toxics Study
E-2
-------
Appendix E
- Monitoring for tributary and air loads for Lake Michigan
- Evaluation of direct loading and sediment contribution to water
pollution
B Integration of air and water models for mass-balance calculations
II Working with the Agency on Toxic Substances Disease Registry
(ATSDR) evaluating chemical exposure from consumption of Great
Lakes fish and health effects on a variety of sensitive or highly exposed
population subgroups
n Working with ATSDR to conduct an air toxics monitoring study in
conjunction with EPA Region 5 and Southeast Chicago Initiative.
Progress on Specifically Mandated Monitoring Networks
n Five master (regional background) stations collecting wet and dry toxics
deposition samples on each of the Great Lakes, begun in 1992 as part
of the Integrated Atmospheric Deposition Network—a joint effort
between the United States and Canada
n Three stations collecting toxics for the Chesapeake Bay, begun in
1990—a joint effort between EPA and the Bay States
n State-run toxics deposition programs for Lake Champlain, which are
to be enhanced through the Lake Champlain Management Conference
under the Lake Champlain Special Designation Act of 1990; and
mercury deposition monitoring for the Lake
Progress by NOAA on Section 112(m) Issues
H Cooperation with the Lake Champlain Research Consortium and the
Vermont Monitoring Cooperative to conduct mercury monitoring and
research on wet and dry deposition of nutrients and HAPs and on mod-
els for meso-scale deposition in the Lake Champlain basin
B Establishment and operation of the Atmospheric Nutrient Input to
Coastal Areas (ANICA) program to develop deposition sampling data
for modeling of atmospheric input, especially to the Chesapeake Bay
B Establishment and operation of the Atmospheric Integrated Research
Monitoring Network (AIRMoN), an activity using state-of-the-art
measurement technologies that should provide quick indication of the
impact of Clean Air Act emission reductions on national air quality.
E-3
-------
-------
Appendix F
Appendix F
Summary of MACT Source Categories Potentially Emitting Great Waters Pollutants
of Concern3
MA.CT Source Category
Industrial Boilers
Institutional/Commercial Boilers
Process Heaters
Primary Aluminum Production
Secondary Aluminum Production
Primary Copper Smelting
Primary Lead Smelting
Secondary Lead Smelting
Lead Acid Battery Manufacturing
Coke By-Product Plants
Ferroalloys Production
Integrated Iron and Steel Manufacturing
Non-Stainless Steel Manufacturing -
Electric Arc Furnace (EAF) Operation
Stainless Steel Manufacturing -
Electric Arc Furnace (EAF) Operations
Iron Foundries
Steel Foundries
Steel Pickling - HCL Process
Asphalt Concrete Manufacturing
Asphalt Processing
Lime Manufacturing
Portland Cement Manufacturing
Petroleum Refineries - Catalytic Cracking
(Fluid and Other) Units, Catalytic
Reforming Units, and Sulfur Plant Units
Petroleum Refineries -
Other Sources not Distinctly Listed
Gasoline Distribution (Stage 1)
Cadmium ,
Compounds
•
•
•
«
•
«
•
•
•
•
•
•
•
Lead
Compounds
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Mercury
Compounds
•
•
•
•
•
•
•
•
•
•
POM
•
•
•
•
•
•
•
•
•
Regulation
Promulgation
Schedule
11/15/2000
11/15/2000
11/15/2000
11/15/1997
11/15/1997
11/15/1997
11/15/1997
4/30/1995b
11/15/2000
11/15/2000
11/15/1997
11715/2000
11/15/1997
11/15/1997
11/15/2000
11/15/1997
11715/1997
11/15/2000
11/15/2000
11/15/2000
11/15/1997
11/15/1997
6/30/95b
ll/23/1994b
(continued)
P-l
-------
Appendix F
Summary of MACT Source Categories Potentially Emitting Great Waters Pollutants
of Concern3 (continued)
ll 111 II 1 III 1 1 1 1 '
(ilACT Source Category
Auto and Light Duty Truck
(Surface Coating)
Printing, Coating, and Dyeing of Fabrics
Hazardous Waste Incinerators
Sewage Sludge Incinerators
Synthetic Organic Chemical
Manufacturing
Dry Cleaning
Plywood/Particle Board
Pulp and Paper Production
Cadmium
Compounds
•
•
•
Lead
Compounds
•
•
•
Mercury
Compounds
•
•
•
POM
•
•
•
•
•
Regulation
Promulgation.
Schedule
11/15/2000
11/15/2000
11/15/2000
11/15/2000
2/28/1994
11/15/1992
11/15/2000
11/15/1997
"The information in this table was extracted from the documents EPA-450/3-21-030 Documentation for Developing the Initial Source
Category List and EPA 455/R-93-048 National Emissions Inventory of Mercury and Mercury Compounds: Interim Final Report.
These documents represent preliminary data only. Pollutants other than those listed may prove to be present in emissions from these
listed sources as more information on source categories becomes available.
b Court-ordered deadlines.
Note: If the EPA misses the deadlines in this schedule for promulgating Federal emissions standards by at least 18 months, section
112(j) of the 1990 Amendments requires State and local agencies to establish case-by-case emission standards. Theses case-by-case
standards must be equal to the level of control that would have been required by the Federal emission standards.
F-2
-------
Appendix G
Appendix G
Preliminary Sranmary of Research
and Program Planning
With the completion of this first report and the ensuing discus-
sions within and outside EPA, it is now appropriate to assess the future
needs and direction of the program, the state of the knowledge, and the
kinds of efforts needed to provide the necessary information on deposi-
tion of air pollutants to the Great Waters. Given that the problem of
atmospheric deposition of toxics to aquatic ecosystems is vastly complex
and that much of the research in this area is extremely expensive, EPA
and other Federal agencies must now determine where efforts are best
spent to collect the most important information to meet the mandate of
Section 112(m) of the Clean Air Act.
The EPA is working on a program strategy to target the most
effective efforts. A preliminary research planning guidance document
was prepared that describes many of the efforts necessary to provide
each kind of information: relative loading, emission inventory/source
characterization, and ecological and human health effects. Summary
charts are provided in this appendix to describe those tasks and to begin
to rank subtasks. It should be noted that the charts on the following
pages are a "first cut" at the research elements and program activities
needed to better define and address these issues. There are undoubtedly
activities that are needed that have not been listed here, and some of
those listed may ultimately prove less important for decisionmaking.
However, EPA, in concert with other Federal agencies, is developing an
overall strategy to address Great Waters issues in the context of other
environmental priorities. The strategy must recognize the realities of
time Qiow long can we wait for an answer before we act or allow im-
pacts by inaction) and money (what funds will continue to be available
for research in this area) and define what activities are necessary to
provide the important pieces of information.
The strategy, anticipated to be completed by mid-1994, is still
being developed, but the essence of it is this: there must be three
ongoing efforts that complement and provide information to each other:
Long-term efforts will work toward developing a more certain
picture and will provide feedback on the effectiveness of maximum
achievable control technology (MACT) standards and other
controls.
G-l
-------
Appendix G
Short-term efforts will focus on important, transferrable 'infor-
mation, usable in an early time frame, especially for regulatory
decisionmaking. For example, the Lake Michigan loading/mass
balance work will provide an integrated picture of one geographic
area as well as provide a transferrable mass-balance methodology.
Justified action is the goal of the program—to determine what,
if any, action is needed to prevent adverse effects and to imple-
ment or recommend that action. This is not one final action, but
a continuum of problem recognition and solution definition over
time, as information becomes available through short- and long-
term efforts.
This strategy will be developed by the EPA Office of Air Quality
Planning and Standards, jointly with the offices and agencies that
participate in program decisionmaking through the Great Waters Core
Project Management Group. It will also undergo peer review and will be
available to interested parties through the Great Waters program.
The following six charts are the summary charts of the prelimi-
nary research planning guidance document. This is a compilation of
many of the tasks necessary to provide complete information on relative
loading, effects, and source identification. Again, the strategy being
developed will define the priority and schedule of the work
according to the resulting information's importance, the ease
with which it can be obtained, and its utility in determining the
need for any additional regulations.
G-2
-------
Appendix G
Ecological Effects Research and Program Needs
Technical
Need
Mechanisms
of Action
Population
Effects
Ecosystem
Effects
Research Issues
Long-term exposure studies with single or low-dose,
embryonic or developmental
Diverse mechanisms for individual effects and
diverse effects by individual mechanisms
Interaction of chemicals
Bioavailability
Effects in reptiles, amphibians, and
chondrichthian fishes
Thresholds for sensitive populations
Eutrophication
Ecosystem dynamics, including invader species
impacts
Broaden base of studied ecosystems to include
warmwater lakes, estuaries, and tropical marshes
Impact of relatively new contaminants
Preliminary
Priority
Banking
1
1
2
1
1
3
1
1
2
3
Estimated
Relative
, Costs
<5d.
'P'P'P
4**
vvv
$$$$
-------
Appendix G
Detailed Human Health-Related Effects Research Needs
Technical
Need
Multiple
reproductive
endpoint
studies of
men and
women
Develop-
mental
Effects
Neuro-
behavioral
Effects
Endocrino-
logical
Effects
Immuno-
logical
Effects
Research Issues
Reproductive couple:
Fertility
Reproductive behavior
Men:
Alterations in libido
Alterations in spermatogenesis
Alterations in reproductive tissue
Women:
Menarche
Menstrual cycle
Menopause
Time to pregnancy
Endometriosis
Pregnancy intervals
Contaminated breast milk
Long-term functional significance of effects
Diminished potential
Developmental biomarkers
Standardized/nonstandardized testing
replication studies
Alteration of dopamine production
Memory and attention deficits
Standardized vs. nonstandardized testing:
Cognitive processing efficiency
Vigilance/sustained attention
Activity level
Long-term functional significance of effects
Delayed effects:
Puberty
Senescence
Menopause
Sex hormones:
Libido
Spermatogenesis
Menstrual cycle
Thyroid hormone alterations
Long-term functional significance of effects
Immunosuppression
Immunoenhancement
Immunological responses and susceptibility:
Primary antibody response
Diseases of viral and bacterial origin
Preliminary
Priority
Ranking
1
2
2
1
I
2
I
2
1
2
1
1
1
1
1
2
2
I
1
1
1
2
1
1
2
2
2
1
1
2
1
1
2
1
2
Estimated
Relative
Costs' .
d»(f*dj
*
(fed?
w
$$
$$
$
$$
$
$$
$$
$
d»
-------
Appendix G
Human Health-Related Effects Research and Program Needs
Technical
Need
Research
Compounds
Biomarker
Development
Noncancer
Endpoints
Interdisciplinary
Organization
HERL
NIEHS
GLIN
RIEN
RISP
Research. Issues
Identify effects across a broader range
of compounds
See detailed table for research issues
Information networks
Vehicle for multidisciplinary research
Symposia
Preliminary
Priority
Ranking
2
3
1
1
1
1
Estimated
Relative
Costs
44*
•PW
$$
$$
64*
vvv
$
Short-ferm
Benefit
Above average
Unknown
High
High
High
Long-Term
Benefit
Above average
Unknown
High
High
High
Source: Great Waters Technical Planning Guidance, July 30, 1993.
G-5
-------
Appendix G
Monitoring Research and Program Needs
Technical Need
and Programs
Atmospheric Deposition
Monitoring Networks
GLAD (Great Lakes)
IADN (Great Lakes)
L. Michigan Network
Chesapeake Bay Network
L. Champlain Station
Narragansett, Delaware,
Massachusetts, and
other bays
National as applied to
Coastal
Atmospheric Measurements
(same as above)
Atmospheric Deposition
Processes
Research Issues
Siting
Trace organic monitoring
Qualify control
Data compatibility with other
stations and networks
Coordination among network parties
Spatial and temporal variability
Inland vs. shoreline vs. open lake
sites
Quality control
Meteorological
Rain, snow, and fog scavenging
Gas/particle partitioning
Particle deposition velocity
Preliminary
Priority
Ranking
2
1
1
2
3
1
2
1
2
1
2
I
•' Estimated; •
Relative
• .:. 'Costs • ,•
$$
$$$
*djd>
-------
Appendix G
Atmospheric Modeling Research and Program Needs
Technical
Need
Source
Attribution
Transport
Description
Model
Interactions
Research Issues
Collect ambient and source signature data for
source-receptor modeling and apportionment,
including source profiles and tracer compounds
Pollutant exchange process: air-soil-plant
Three-dimensional windfields and diffusion
coefficients
Precipitation field effects
Nested regional models
Nested hemispheric and/or global scale models
Preliminary
Priority
Ranking
1
1
2
I
1
2
Estimated
Relative
Costs
****
•PW'P
$$
$$
$$
d;**
vvv
d?d?d>tfc
WViP
Short-Term
• Benefit
High
High
Above average
High
High
High
Long-Term
Benefit
High
High
Above average
High
High
High
Source: Great Waters Technical Planning Guidance, July 30, 1993.
G-7
-------
Appendix G
Emission Inventory and Source Characterization Research and Program Needs
., , ; v •
Technical Need
Statewide Emission Inventory
California Air Research Board
GLC (8 Great Lakes States)
Other local areas and States
are also involved in developing
HAP emission inventories,
including Puget Sound,
Louisiana, Maryland, Texas,
Arizona, and New Mexico
Regional Emissions Inventory
GLC
Development of re-emission
estimates for Hg and OC pesti-
cides that have been discontin-
ued in the United States
Definition and Characterization
of Urban Air Plume
Lake Michigan and Chesapeake
Bay Cooperative Agreement
(LMCB)
Southwest Lake Michigan
Urban Area Air Toxic Inventory
Research Issues
Quality control
Maximal bottom-up data
Chemical focus
Coordination of inventories
Completeness of source types
and chemical speciation
Define PCBs, POMs, and
TCDDs/TCDFs for inventory
purposes
Same as above
Development of analytical
methods to determine
re-emission
Development of re-emission
estimates
Increased availability of pesticide
manufacturing and usage data
See emission inventory priorities
(above) and modeling section
of report
Preliminary
Priority
Banking
1
1
2
3
I
2
2
2
1
Estimated
..Relative '•:
. '.';. 'Costs" TV
****
wW>
$$$$
$$
$
$$$
$$
$$
4>4>
-------
Appendix G
Atmospheric Component of Mass Balance Studies Research and Program Needs
Technical Need
Loading Estimates
Lake Michigan Mass Budget/
Mass Balance
Chesapeake Bay Basin-Wide
Toxics Reduction
Wet Deposition
Dry Deposition
Microlayer
_ [Research. Issues ,
Increase understanding
of atmospheric deposition
processes
Improve accuracy of loading
estimates, particularly for
atmospheric deposition
Speciation of trace elements,
Hg, and N (DON)
Gas/aerosol distribution of SOCs
Aerosol scavenging coefficient
of SOCs
Aerosol deposition velocity of
trace elements and SOCs
SOC speciation in water
Hg aerosol reactivity
DON aerosol concentration
Nitrogen gas/water partitioning
Hg gas exchange (flux)
Improved sampling
methodologies
Development of assay techniques
Biologic effects research
Process research and integration
into air and mass balance
models
Microlayer symposium
' Preliminary
Priority
Ranking '
1
1
2
2
2
1
1
1
1
1
1
2
1
2
2
1
Estimated
Relative ,
- Costs
These rela-
tive costs are
discussed in
the specific
research areas
within the
planning
guidance.
d>d>d>
VW
$$
$$
***
PPv
-------
-------
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-453/R-93-055
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
First Report to Congress on Deposition of Air Pollutants to the
Great Waters
5. REPORT DATE
May 1994
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Amy B. Vasu and Melissa L. McCullough
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Standards Division
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D2-0065
68-D2-0189
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
IS. SUPPLEMENTARY NOTES
16. ABSTRACT
This report provides an assessment of the following: (1) the contribution of atmospheric deposition
to pollutant loadings to the Great Lakes, Chesapeake Bay, Lake Champlain, and coastal waters (i.e., "the
Great Waters"), (2) the environmental and human health effects caused by the deposited pollutants, (3)
the sources of these pollutants, and (4) whether atmospheric loadings cause or contribute to exceedances
of water quality standards or criteria. The report also includes recommendations for actions to be taken
to address this air and water quality problem. Recommendations include EPA committing to do the
following: to propose certain emission standards early for some sources of Great Waters pollutants, to
consider further regulation of some area sources that emit Great Waters pollutants, to propose a revised
Municipal Waste Combustor rule by summer 1994, and to publish an advance notice of proposed
rulemaking to establish lesser-quantity emission rates for sources emitting less than 10 tons annually of
Great Waters pollutants. Additional recommendations, addressing authorities beyond the Clean Air Act
and also focusing on further research efforts, are included in the report.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Atmospheric Deposition
Air Toxics
Great Waters
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
21. NO. OF PAGES
136
20. SECURITY CLASS (Page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
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