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Mercury in the Chesapeake Bay Watershed
Briefing for the Implementation Committee
Prepared by the Toxics Subcommittee
Draft Release Date 1/21/03
What is the Purpose of this Briefing?
The Toxics Subcommittee (TSC) has developed this document to inform the Implementation
Committee (IC) about mercury pollution and its impact to the Chesapeake Bay watershed. This
briefing provides some background information on mercury contamination and identifies the role
of the Chesapeake Bay Program in reducing this contamination. In particular, the TSC seeks the
assistance of the IC in pursuing the best means of managing the growing number of fish advisories
related to mercury in the Chesapeake Bay watershed. Controlling sources of mercury in the
watershed is complicated by the fact that atmospheric deposition can be a dominant pathway,
resulting from mercury emissions generated both inside and outside of the Chesapeake Bay
watershed. The TSC requests that the IC provide leadership and advice on the best way to prevent
and reduce mercury releases into the Chesapeake Bay watershed from sources inside and outside
the watershed.
The Toxics 2000 Strategy commits the CBP to ensure that fish are safe to eat by all watershed
residents and visitors. The TSC has decided to focus initial efforts on mercury advisories because
there are more opportunities for controlling mercury than for other chemicals contributing to fish
consumption advisories in the watershed (e.g., PCBs, mirex, chlordane, and kepone), since mercury
is currently being used and released. The Toxics Subcommittee and its Fish Advisory Workgroup
will be developing strategies for dealing with these contaminants as well.
BACKGROUND:
What is the Scope of the Mercury Problem in the United States?
Twenty eight percent of lakes and approximately 14% of river miles in the United States are under
fish advisories, and, more alarmingly, 71% percent of all coastal waters of the contiguous 48 states
were under advisory in 2001. Seventy five percent of all advisories in the nation have been issued
at least in part because of mercury contamination (US EPA, 2002). The number of states that have
issued fish consumption advisories due to mercury has risen steadily from 27 in 1993 to 44 in 2001.
Over 415,000 river miles and 10 million lake acres are under mercury advisories nationwide (U.S.
EPA, 2002). As a result of the scope of the advisories and the potential risk to humans from
mercury exposure, the Environmental Protection Agency and the Food and Drug Administration
have provided national advice and the Bay watershed jurisdictions have issued advisories regarding
minimizing exposure to mercury associated with fish consumption.
Is Mercury a Problem in the Chesapeake Bay Watershed?
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Yes. In the Chesapeake Bay watershed, there are a growing number of fish advisories due to
mercury contamination. In 2001, Pennsylvania issued a statewide fish advisory for mercury in all
its waters and Maryland issued a statewide advisory for mercury in its freshwater impoundments.
Virginia has issued mercury advisories for four river reaches due to historical uses of mercury, and
New York has issued three advisories. It is important to note that the number and scope of
advisories within each state may reflect the extent of evaluation of the problem, not the relative level
or spatial scale of contamination.
In addition to the fish consumption advisories, the 1999 Toxics Characterization report identified
mercury as one of six metals that are accumulating to toxic amounts in the sediment of several tidal
rivers (Chesapeake Bay Program, 1999a). It is estimated that ninety percent of the mercury that
enters these tidal rivers gets trapped in the tidal river sediment and does not get flushed out of the
Bay (Chesapeake Bay Program, 1999b).
What are the Human Health and Environmental Concerns with Mercury?
Methylmercury bioaccumulates through the food chain and, once in the human body, can affect the
fetal and adult nervous systems. Human exposure to mercury occurs primarily through eating
contaminated fish. The developing fetus is the most sensitive to mercury and, therefore, women of
child-bearing age are the population of greatest concern. Fetuses exposed to mercury can experience
a variety of abnormalities such as neurological damage, learning disabilities, and delayed
development. Populations subsisting primarily on fish have a higher consumption rate and are at
greater risk.
What are the Biggest Sources of Mercury?
Scientists agree that atmospheric deposition is the dominant source of mercury loading to the aquatic
environment. According to EPA's 1997 Mercury Study Report to Congress, coal-fired electric
utilities are the largest anthropogenic source of mercury air emissions in the United States. Utilities
are followed by municipal waste combustors, then medical waste incinerators, and hazardous waste
combustors. (US EPA, 2002). Other sources of mercury are industrial or chemical manufacturers
such as chlorine plants, wastewater treatment plants, dental offices, and consumer products such as
toothpaste and lotions.
In the atmosphere, mercury is transported by wind and reaches waters either through direct
deposition or as runoff from the land after a storm event. In the water, biological processes can
transform the mercury into methylmercury, a highly toxic form. Small organisms and plants take
up the methylmercury as they feed. Animals that are higher up the food chain, such as fish,
bioaccumulate mercury when they eat plants and organisms containing mercury. In turn, humans
accumulate mercury when they consume contaminated fish. The higher up the food chain, the
higher are the levels of mercury.
Although the Chesapeake Bay airshed for mercury has not been defined yet, it is likely that mercury
originates from sources both inside and outside the watershed.
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In addition to existing sources, there are localized areas within the Bay watershed where mercury
concentrations in sediments are of concern due to legacy sources (e.g., past industrial discharges).
These areas, if disturbed, could result in increased mercury into the water column.
How will Current and Proposed Regulatory Programs Help Address Mercury Contamination
in the Chesapeake Bay Watershed?
In the U.S., the industrial demand for mercury has significantly dropped due to a number of actions,
including federal bans on mercury additives in paint and pesticides, industry efforts to reduce
mercury in batteries, and state-mandated recycling programs. The EPA also has taken action to
reduce mercury emissions from municipal waste combustors, medical waste incinerators, and
hazardous waste combustors. Legislation to reduce mercury emissions from the electricity
generation sector has been introduced in Congress. This legislation is the Clear Skies Act, which
calls for cuts in mercury emissions by 69 percent by 2018.
What Research is Underway to Better Understand Mercury Pollution?
There are several activities underway at the national level to better understand mercury pollution
in order to design (and strengthen) appropriate control policies. Some of these activities are EPA's
Mercury Research Strategy, the USGS/EPA Mercury Roundtable, EPA's PBT Monitoring Strategy,
the METAALICUS study (Mercury Experiment to Assess Atmospheric Loading in Canada and the
United States), the USGS national pilot study, the EPA Mercury Maps and various State initiatives.
Activities being handled at the state level include Maryland's expanded fish survey of largemouth
bass in major reservoirs, striped bass, largemouth bass and white perch in the upper, mid and lower
Bay, investigation of the effects of mercury emitted by coal-fired utilities using certain air pollution
control devices, and mercury modeling to compare the impacts of regional emission sources to those
in Maryland. Pennsylvania has established several new mercury deposition monitoring sites within
and near Pennsylvania portion of the Bay watershed to better quantify mercury deposition. These
and other activities will likely play a role in improving our understanding of mercury effects in the
Chesapeake Bay region.
What Pollution Prevention Efforts are Occurring in the Signatory Jurisdictions' Programs?
Pennsylvania's Businesses for the Bay team is working wastewater treatment plant (WWTP)
managers, local watershed associations, and others, to develop a workshop/educational program
targeting WWTPs for education on pollution prevention efforts to reduce mercury. They have
proposed to involve the Pennsylvania Dental Association, Geisinger Health System and PA B4B
members (and other interested parties) in this effort. At present they are in the formative stages
of this effort.
Virginia has a multi-faceted approach to mercury pollution prevention via the Virginia
Department of Environmental Quality's (VADEQ) mercury reduction initiative. The Virginia
Department of Health collaborated with the Virginia Dental Association to hold a successful
2001 elemental mercury collection effort. The VADEQ is also partnering with the Virginia
Dental Association to produce a best management practices manual for Virginia dentists. The
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VADEQ collected elemental mercury and thermometers 17 schools in 2001, and distributed
digital mercury-free thermometers and educational materials. Other Virginia stakeholders (the
Wildlife Federation, Merck & Co, a Healthcare chain) have followed suit with thermometer
exchanges in 2002. The VADEQ is also working with hospitals on a Pollution Prevention
Healthcare Challenge to move towards the EPA's goal of eliminating mercury in hospitals by
2005. The VADEQ is also developing ideas and partnerships with the Department of Defense,
Virginia Department of Education and others, on initiatives such as thermostat and fluorescent
light bulb collection.
Maryland has also adopted a multi-faceted approach to mercury pollution prevention. The
Maryland Department of the Environment has funded grants for the upcoming development of a
Hospitals for a Healthy Environment campaign for Maryland, to be conducted in collaboration
with Healthcare Without Harm and the American Hospitals Association, with the goals of
eliminating mercury waste by 2005. Maryland is also working to develop a program of mercury
reduction outreach and services to the construction industry and general public.
The District of Columbia has a "Mercury Free D.C." program that addresses a number of aspects
of pollution prevention. The Mercury Exchange Program is a joint venture between the D.C.
Department of Health and the D.C. Fire Department. The Fire Department will accept mercury
thermometers from any institution in the District of Columbia in exchange for a non-mercury
one. In the Mercury Free Hospitals initiative, hospitals in D.C. pledged to rid their facilities of
mercury in 3 to 5 years. Finally, the District has initiated a draft voluntary program to audit
hospital hazardous waste management, to allow D.C. officials to review the facility management
of waste disposal and reduce improper waste disposal.
ROLE OF THE CHESAPEAKE BAY PROGRAM:
What Can the Chesapeake Bay Program Do about Mercury Contamination?
The Chesapeake 2000 Agreement commits the CBP to fulfill the 1994 goal of a Chesapeake Bay free
of toxics by reducing or eliminating the input of chemical contaminants from all controllable sources
to levels that result in no toxic or bioaccumulative impact on the living resources that inhabit the
Bay or on human health. The Agreement also commits to "understanding the effects and impacts of
chemical contaminants to increase the effectiveness of management actions" and "through continual
improvement of pollution prevention measures and other voluntary means, strive for zero release
of chemical contaminants from point sources, including air sources."
The Toxics 2000 Strategy commits the CBP to ensure that the public is aware of the fish
consumption advisories and that the advisories are protective of all populations. Furthermore, the
Toxics 2000 Strategy commits to develop contaminant prevention and reduction strategies to ensure
that fish are safe to eat.
Below is a list of actions with associated leads to address mercury contamination in the watershed.
The TSC has identified where it needs the expertise and leadership from the Implementation
Committee.
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I.	Outreach and Education
IC Role:
1. Receive regular progress updates and provide guidance when necessary.
TSC Role:
1.	Inform the public about the advisories.
2.	Identify subpopulations at greatest risk.
3.	Develop educational materials that cater to these sub-populations to inform them of
the advisories and associated risk.
The Toxics Subcommittee's Fish Advisory Workgroup partnered with Johns Hopkins
University during the summer, 2002 to survey 3,000 Maryland anglers about their fish
consumption habits and to conduct pilot dock interviews in the Baltimore watershed. The
purpose of this survey was to determine whether or not the current advisories are protective
of all populations and to determine what educational methods work best with different
populations. Results from this survey should be available early in 2003. It will be important
to expand this survey to other key areas of the watershed, provided that funding is available.
II.	Develop Control Strategies to Reduce Mercury Releases from Sources located
in the four Bay watershed jurisdictions
IC Roles:
L Ensure that federal and state air and water programs work together to develop
control strategies.
2. Determine whether specific CBP reduction goals for mercury are necessary and
give approval of any new targets.
TSC Roles:
1.	Identify the mercury sources, including point source discharges to water and
stationary sources located in the jurisdictions emitting mercury in the air.
2.	Promote voluntary reductions of mercury from these sources through programs like
Businesses for the Bay. Build on the Toxics 2000 Strategy commitment to achieve
a 15% reduction of chemicals of concern (which includes mercury) in impacted areas
and areas at risk by 2005.
3.	Identify urban storm water best management practices that remove mercury and
promote them in target areas of the watershed (Coordinated with the Stormwater
Workgroup).
4.	Determine the importance of mercury sources outside the four Bay jurisdictions based
on discussion with scientists and existing data. If air sources in other states
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contribute significantly to mercury contamination in the Bay watershed, then broader
efforts will be considered.
5.	Identify any gaps or shortcomings of national regulations in effectively reducing or
preventing mercury contamination in the watershed.
6.	Partner with other programs throughout the country to further reduce mercury
emissions if mercury sources in non-watershed states are important and if regulations
are not sufficient to prevent mercury loads from these sources.
III. Better Define Problem Through Monitoring and Research
We recognize that we must act now on the information we have in order to reduce mercury
inputs into the Chesapeake Bay watershed. However, we also realize the importance of
continually improving our understanding of the science to ensure that our approach and
management strategies are effective.
IC Role:
L Provide the management questions that need to be answered by science in order
to better control mercury releases to the Chesapeake Bay watershed
TSC Roles:
1.	Summarize the state of knowledge regarding atmospheric deposition of mercury onto
the Bay watersheds and waters.
2.	Identify data gaps that must be filled to improve our approach for managing mercury
releases.
References
Chesapeake Bay Program. 1999a. Targeting Toxics: A Characterization Report - A Tool for
Directing Management and Monitoring Actions in the Chesapeake Bay's Tidal Rivers, June
1999.
Chesapeake Bay Program. 1999b. Chesapeake Bay Basin Toxics Loading and Release
Inventory, CBP/TRS 222-100, EPA 903-R-99-006.
Mason, Rob. 2002. Personal communication to the Toxics Subcommittee regarding atmospheric
Mercury (Hg) deposition rates in Maryland are high relative to other regions of the USA
US EPA, Office of Water. 2002. EPA Fact Sheet, Update: National Listing of Fish and Wildlife
Advisories. EPA-823-F-02-007.
U.S. EPA. 2002. Mercury Frequently Asked Questions.
www.epa.gov/mercury/information. htm#fact-sheets.
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