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October 1, 1998


Mr. Chairman, Members of the Subcommittee, I am pleased to have this opportunity to offer this testimony in hopes that it will contribute to the Subcommittee's discussion of science issues involved in assessing health and ecological impacts of mercury exposure.

Mercury (Hg) is a basic element, it is neither created nor destroyed, and has always been a component of the earth's dynamic systems. What has changed with time and what has caused increasing concern about mercury and mercury exposure is the addition of the human component to the planet's complex systems. Mercury cycles in the environment as a result of natural and anthropogenic (human) activities. The amount of mercury mobilized and released into the biosphere, and thus biologically available within the environment, has increased since the beginning of the industrial age as a result of increasing anthropogenic activities, raising concern about the potential for public health and ecological impacts. The scientific community knows a lot about the human health and ecological effects of mercury and mercury exposure, and has agreed, in spite of the scientific uncertainties, that mercury is an important environmental problem.

The U.S. Environmental Protection Agency (EPA) has been at the forefront on science issues and control activities regarding mercury. The Agency's study of the human health and ecological assessment of mercury exposure has been centered in the National Center for Environmental Assessment (NCEA), one of five major components of EPA's Office of Research and Development (ORD). NCEA has major responsibility in EPA for the conduct of chemical- specific risk assessments in support of EPA regulatory programs, the development of Agency-wide guidance on risk assessment, and the conduct of research to improve risk assessment. NCEA occupies a critical position in the Agency between the researchers in other ORD components who are generating new findings and data, and the regulators in the EPA program offices (e.g., pollution prevention and toxic substances, air, water and waste programs) and regions who must make regulatory, enforcement, and remedial action decisions.

As Director of NCEA, I am committed to the development of national and international approaches to the testing and assessment of the fate and effects of environmental agents. Prior to my appointment as Center Director, I was Director of the Agency's Office of Health and Environmental Assessment, a position which I held since 1988. I began my EPA career in 1979 as a Health Scientist in the EPA's Office of Toxic Substances. I received my Ph.D. in 1976 from UCLA in Cell Biology and Biochemistry, an M.A. (1972) in Zoology from the same institution and a B.S. (1970) from Loyola University, Los Angeles. I serve on a number of committees and advisory boards including: the National Toxicology Program's Executive Committee, EPA Liaison to the Public Health Service Environmental Health Policy Committee, and past Executive Secretary of the Federal Coordinating Council on Science Engineering and Technology's Ad Hoc Working Group on Risk Assessment. I have also served on the Office of Science and Technology's Committee on Environment and Natural Resources' (CENR) Risk Assessment Subcommittee, and I was co-chair of the Federal Liaison Group to the National Academy of Sciences Committee on Risk Assessment Methods. I am also a past member of the Science Advisory Panel of the Chemical Industry Institute of Toxicology, and a member of the Science Advisory Panel on Electromagnetic Fields (EMF) Research at the Electric Power Research Institute (EPRI). I am currently a member of the Council of the Society for Risk Analysis, and on the editorial boards of two respected science journals, Risk Analysis since 1987 and Environmental Health Perspectives since 1997.

NCEA and the Office of Air and Radiation's (OAR) Office of Air Quality Planning and Standards (OAQPS), were the lead Agency offices overseeing the development of the 1997 Mercury Study Report to Congress. Work on the Report began in 1992. On December 19, 1997, the Agency released an eight-volume report to Congress. The Report fulfills the requirements of section 112(n)(1)(B) of the Clean Air Act as amended in 1990. The Report inventories the quantity of mercury emissions to the air from a number of sources related to human activity; estimates the health and environmental impacts associated with these combined emissions; and describes the technologies (and associated costs) available to control mercury emissions from these sources. The Report was reviewed and approved by EPA's Science Advisory Board (SAB), a panel of independent scientific experts, and was developed with substantial input by industry groups, the general public, and state, local, and other Federal government agencies including the U.S. Fish and Wildlife Service, Department of Energy, Food and Drug Administration, National Institute of Environmental Health Sciences, Agency for Toxic Substances and Disease Registry, and National Oceanic and Atmospheric Administration.

The Mercury Study Report to Congress

The Mercury Study Report to Congress, prepared by EPA, provides an assessment of the magnitude of U.S. mercury emissions by source, the health and environmental implications of those combined emissions, and the availability and cost of control technologies. As the state-of-the-science for mercury is continuously and rapidly evolving, this Report should be viewed as a "snapshot" of our current understanding of mercury. The Report also identifies areas where further research is needed to provide a quantitative risk assessment.

Most of the mercury in the atmosphere is elemental mercury vapor, which circulates in the atmosphere for up to a year, and hence can be widely dispersed and transported thousands of miles from sources of emission. Most of the mercury in water, soil, sediments, or plants and animals is in the form of inorganic mercury salts and organic forms of mercury (e.g., methylmercury). The inorganic form of mercury, when either bound to airborne particles or in a gaseous form, is readily removed from the atmosphere by either precipitation or dry deposition. Wet deposition is the primary mechanism for transporting mercury from the atmosphere to surface waters and land. Even after it deposits, mercury commonly is re-emitted back to the atmosphere either as a gas or associated with particles, to be re-deposited elsewhere. As it cycles between the atmosphere, land, and water, mercury undergoes a series of complex chemical and physical transformations, many of which are not completely understood.

What is well understood is that mercury accumulates most efficiently in the aquatic food web after being transformed into methylmercury in sediments. Predatory fish and fish-eating birds and mammals at the top of the food web generally the highest mercury concentrations in their body tissues. Because of its physico-chemical properties and strong propensity to bioaccumulate, nearly all of the mercury that accumulates in fish tissue is methylmercury. Inorganic mercury, which is less efficiently absorbed and more readily eliminated from the body than methylmercury, does not tend to bioaccumulate.

Mercury Emissions and Deposition in the United States

The best point estimate of annual anthropogenic U.S. emissions of mercury, based on l994-1995 data, is 158 tons. Roughly 87 percent of these emissions are estimated to be from combustion sources, including waste and fossil fuel combustion. Contemporary anthropogenic emissions are only one part of the mercury cycle. Human activities today are causing releases from the reservoirs that already exist in land, water, and air, both naturally and as a result of previous human activities. The flux of mercury from the atmosphere to land or water at any one location is comprised of contributions from the natural global cycle including re-emissions from the oceans, regional sources, and local sources. Local sources could also include direct water discharges in addition to air emissions. Past uses of mercury, such as fungicide application to crops, are also a component of the present mercury burden in the environment.

Computer modeling of long-range transport of mercury suggests that about one-third (~ 52 tons) of U.S. anthropogenic emissions are deposited, through wet and dry deposition, within the contiguous 48 States. The remaining two-thirds (~ 107 tons) is transported outside of U.S. borders where it diffuses into the global cycle. In addition, the computer simulation suggests that another 35 tons of mercury from the global cycle is deposited in the U.S. for a total deposition of roughly 87 tons annually. One estimate of the total annual global input to the atmosphere from all sources including natural, anthropogenic, and oceanic emissions is 5,500 tons. Based on this, U.S. anthropogenic sources are estimated to have contributed about 3 percent of the 5,500 tons in 1995.

Based on model estimates, the highest deposition rates from anthropogenic and global contributions for mercury are predicted to occur in the southern Great Lakes and Ohio River valley, the Northeast and scattered areas in the southeastern United States. The location of sources, the chemical species of mercury emitted, and climate and meteorology are key factors in mercury deposition. For instance, humid locations have higher deposition than arid locations.

Public Health Impacts

Epidemics of mercury poisoning following high-dose exposures to methylmercury in Japan and Iraq demonstrated that neurotoxicity is the health effect of greatest concern and that effects on the fetal nervous system occur at lower exposures than do effects on the adult nervous system. Minimally affected mothers have given birth to severely affected infants. Dietary methylmercury is almost completely absorbed into the blood and distributed to all tissues including the brain; it also readily passes through the placenta to the fetus and fetal brain. To describe the implications of chemical exposures on human health, including the impacts of methylmercury exposure, the Agency uses the concept of a "reference dose." The reference dose (RfD) is an amount of methylmercury, which when ingested daily over a lifetime is anticipated to be without adverse health effects to humans, including sensitive subpopulations. At the RfD or below, exposures are expected to be safe. The risk following exposures just above the RfD is uncertain, but it is clear that risk increases as exposures to methylmercury increase significantly above the RfD.

EPA has on two occasions published RfDs for methylmercury which have represented the Agency consensus for that time. The original RfD of 0.3 micrograms per kilogram body weight per day (g/kg/day), based on effects seen in adults, was determined in 1985 by EPA's agency-wide consensus workgroup. This assessment was subsequently included on the Agency's Integrated Risk Information System (IRIS). The critical effect was nervous system damage in an Iraqi adult population exposed to methylmercury through consumption of contaminated grain. The effect seen at lowest dose was changes in sensation or numbness.

The current RfD of 0.1 g/kg/day, based on effects seen in children, was established as Agency consensus in 1995. The revised RfD was estimated by extrapolating from the high-dose exposures that occurred in the Iraqi incident to impacts on the most sensitive individuals in that population-- the developing fetus.

At the time of the Mercury Study Report to Congress, it became apparent that considerable new data on the health effects of methylmercury in humans were emerging. However, as many of these new data had either not been published or have not yet been subject to rigorous review, EPA decided that it was premature to make a change in the 1995 methylmercury RfD at that time. This decision was supported by the Agency's SAB, a public advisory group providing extramural scientific information and advice to the Administrator and other officials of the EPA. The SAB is structured to provide balanced, independent expert assessment of scientific matters relating to problems facing the Agency. Their report makes the following statement:

"In general, from the standpoint of looking at human health effects and the uncertainties, the draft report is a very good document and an important step forward in terms of bringing the relevant information together in one place for the first time. The current RfD, based on the Iraqi and New Zealand data, should be retained at least until on-going Faeroe and Seychelles Islands studies have progressed much further and been subjected to the same scrutiny as has the Iraqi data."

With respect to the on-going, two large epidemiology studies in the Seychelles Islands and in the Faeroe Islands that were designed to evaluate childhood development and neurotoxicity in relation to fetal exposures to methylmercury in fish-consuming populations, the SAB report states:

"Investigators conducting two new major prospective longitudinal studies--one in the Seychelles Islands, the other in the Faeroe Islands--have recently begun to publish findings in the literature and are expected to continue releasing their findings during the next 2-3 years. These studies have advantages over those cited in the previous paragraph in that they have much larger sample sizes, a larger number of developmental endpoints, potentially more sensitive developmental endpoints, and control a more extensive set of potential confounding influences. On the other hand, the studies have some limitations in terms of low exposures (to PCBs in the Faeroes) and ethnically homogenous societies. Since only a small portion of these new data have been published to date and because questions have been raised about the sensitivity and appropriateness of the several statistical procedures used in the analyses, the Subcommittee concluded that it would be premature to include any data from these studies in this report until they are subjected to appropriate peer review. Because these data are so much more comprehensive and relevant to contemporary regulatory issues than the data heretofore available, once there has been adequate opportunity for peer review and debate within the scientific community, the RfD may need to be reassessed in terms of the most sensitive endpoints from these new studies."

To respond to the SAB's comment regarding the future need to reassess the current RfD in light of the newly emerging data and because of various limitations and uncertainties in the available data, both the Iraqi data and those newly published from the ongoing studies, the EPA and other Federal agencies intend to participate in an interagency review of the human data on methylmercury. A scientific workshop scheduled later this year will include review of the most recent studies from the Seychelles Islands and the Faeroe Islands. The purposes of this workshop are to refine the estimates of the level of exposure to mercury associated with subtle neurological endpoints and to further consensus between all of the Federal agencies. Additional information on this upcoming meeting is included in this testimony. After this process, the EPA will determine if a change in the underlying scientific basis for, or the numeric estimate of, the RfD for methylmercury is warranted.

While fate and transport of mercury in the environment is complex, the scientific community agrees that fish consumption is the major pathway for human and wildlife exposure to methylmercury. The data support a plausible link between anthropogenic releases of mercury from industrial and combustion sources in the U.S. and methylmercury in the fish in U.S. lakes and streams. However, these fish methylmercury concentrations also reflect additional sources of methylmercury. These include background concentrations of mercury (which may consist of mercury from natural sources), as well as mercury from previously emitted anthropogenic and natural sources. Given the current scientific understanding of the environmental fate and transport of this element, it is not possible to quantify how much of the methylmercury in non-commercial fish consumed by the U.S. population is contributed by U.S. emissions relative to other sources of mercury (such as natural sources and re-emissions from the global pool). As a result, it cannot be predicted how much nor over what time period a reduction in mercury emissions will result in decreased levels of methylmercury in fish. This is an area of ongoing study.

Critical elements in estimating methylmercury exposure and risk from fish consumption include the species of fish consumed, the concentrations of methylmercury in the fish, the quantity of fish consumed, and how frequently fish is consumed. The typical U.S. consumer eating fish from restaurants and grocery stores is not in danger of consuming harmful levels of methylmercury from fish and is not advised to limit fish consumption. The levels of methylmercury found in the most frequently consumed commercial fish are low, especially compared to levels that might be found in some non-commercial fish from fresh water bodies that have been affected by mercury pollution.

While most U.S. consumers need not be concerned about their exposure to methylmercury, some exposures may be of concern. Those who regularly and frequently consume large amounts of non-commercial fish -- either marine fish that typically have much higher levels of methylmercury than the rest of seafood, or freshwater fish that have been affected by mercury pollution -- may be more highly exposed. Because the developing fetus is the most sensitive to the effects from methylmercury, women of child-bearing age are regarded as the population of greatest interest. An analysis of dietary surveys led the EPA to conclude that between 1 and 3 percent of women of child-bearing age (i.e., between the ages of 15 and 44) eat sufficient amounts of fish to be at risk from methylmercury exposure, depending on the methylmercury concentrations in the fish. These consumers should be aware of the fish advisories issued by the Food and Drug Administration and various States that suggest limiting the consumption of fish containing higher levels of mercury. Such advisories in the U.S. have been issued by 41 states (including 11 state-wide advisories) and by some Native American Tribes, warning against consumption of non-commercial of fish contaminated with methylmercury.

Environmental Impacts

The pattern of mercury deposition nationwide influences which eco-regions and eco-systems will be more highly exposed. Piscivorous (fish-eating) birds and mammals are more highly exposed to mercury than any other known component of natural ecosystems. Adverse effects of mercury on fish, birds and mammals include reduced reproductive success, impaired growth and development, and behavioral abnormalities, and even death.

Mercury contamination of the food web has been well documented. In addition, the endangered Florida panther and the wood stork, as well as populations of loons, eagles, and furbearers such as mink and otter have been found to have elevated tissue mercury concentrations. These species are at high risk of mercury exposure and effects because they either are eat fish or eat other fish-eaters. Concentrations of mercury in the tissues of wildlife species have been reported at levels associated with adverse health effects in laboratory studies with the same species. However, field data are insufficient to conclude whether piscivorous wading birds or mammals have suffered adverse effects due to airborne mercury emissions. Modeling analyses conducted for the Report suggest that it is probable that individuals of some highly exposed wildlife subpopulations are experiencing adverse effects due to airborne mercury emissions.

Mercury Control Technologies

Mercury is widely used in industry because of its diverse properties and serves as a process or product ingredient in several industrial sectors. However, industrial demand for mercury declined by about 75 percent between l988 and l996, due largely to the elimination of mercury additives in paints and pesticides and the reduction of mercury in batteries. Most of the emissions of mercury are produced when waste or fuel containing mercury is burned. The EPA has already finalized emission limits for municipal waste combustors and medical waste incinerators. Once these regulations are fully implemented in 2002, emissions from these categories will decline at least 90 percent from 1995 levels. In addition, mercury emission limits have been proposed for hazardous waste incinerators.

The largest remaining identified source of mercury emissions is coal-fired utility boilers. Although a number of mercury control technologies are being evaluated for utility boilers, most are still in the research stages, making it difficult to predict final cost-effectiveness as well as the time required to scale-up and commercialize the technologies. Because the chemical species of mercury emitted from boilers varies from plant to plant, there is no single control technology that removes all forms of mercury. There remains a wide variation in the end costs of control measures for utilities and the possible impact of such costs on utilities. Preliminary estimates of national control costs for utility boilers (based on pilot scale data) are in the billions of dollars per year. Ongoing research, as well as research needs related to mercury controls for utilities, are described in the Report.

In addition, cost-effective opportunities to deal with mercury during the product life-cycle need to be pursued. A balanced strategy which integrates end-of-pipe control technologies with material substitution and separation, design-for-environment, and fundamental process change approaches is needed. Also, international efforts to reduce mercury emissions as well as greenhouse gases will play an important role in reducing inputs to the global cycle of mercury.

Mercury Research Needs

As described above, the Mercury Study Report to Congress identifies mercury as a human health and environmental problem requiring additional scientific and technical research. While mercury has long been known to be neurotoxic, the development of the final Report and its assessment of risk, is an example of an iterative process that by its nature includes a discussion of identified research needed to increased our understanding of the magnitude and extent of the problem. The Report suggests additional research in the following areas:

In addition, other Agency reports (e.g., Great Waters Second Report to Congress - June 1997, Utility Air Toxics Report to Congress -- February 1998) stress the adverse impacts of mercury on both human health and the environment. The Agency's Clean Water Action Plan; Restoring and Protecting America's Waters (February 1998) cites mercury as a complex environmental challenge because of its ability to circulate in the atmosphere both locally and globally and eventually biomagnify in the aquatic food web where it is consumed by both humans and wildlife. The Office of Air and Radiation (OAR), the Office of Solid Waste and Emergency Response (OSWER), and the Office of Water (OW) are faced with addressing mercury as part of their regulatory programs. The above Offices, along with a number of other Agency Program and Regional Offices, formed the Mercury Task Force and the Task Force identified cross-office actions to address mercury in the draft Mercury Action Plan that is currently undergoing internal EPA review.

In response to this heightened Agency activity regarding mercury, EPA's Deputy Administrator asked ORD to initiate a research program directed at responding to these activities and supporting the Agency's proposed and future actions on mercury. It was determined that there were several facets in developing a mercury research program including:

1) short-term research needs that required immediate attention and re-prioritization of Agency research projects and resources -- FY1998/FY1999 Mercury Research Projects; and
2) longer-term research needs for the 2003-2005 time period -- Mercury Research Strategy. FY1998/FY1999 Mercury Research Projects

Immediately after the submission of the Mercury Study Report to Congress, the need to examine EPA's current mercury research in light of the Report and other recent mercury-related activities was clear. Was the Agency doing and had the Agency planned the appropriate research that would provide information to reduce the uncertainties detailed in the reports? Was the Agency doing and had the Agency planned the appropriate research that would provide information to the program offices that are faced with addressing mercury as part of their regulatory programs? As a result of these questions, current research projects were examined and immediate research needs for FY 1998 and FY1999 were identified and subsequently prioritized. These projects are consistent with priorities identified in the Mercury Study Report to Congress and the evolving Mercury Research Strategy, discussed below. ORD has responded with a targeted mercury research program. This research program represents an increased level of effort on which future mercury research initiatives would build. The FY1998 and FY1999 research projects include:

.    Resolve Health Assessments for Methylmercury -- This project focuses on resolving issues surrounding mercury exposures associated with adverse health effects, including scientific questions raised when developing reference doses and other quantitative values. This project supports interagency workshops and activities related to resolution of which data sets describing adverse health effects of methylmercury on developmental effects of methylmercury exposure in humans (e.g., Iraqi data, Faeroe Islands data, Seychelles Island data) should serve as the primary data set for revising the RfD, if necessary.
.    Control Technology Projects - These control technology projects are directed at developing more effective emission controls on coal-fired utilities and industrial boilers, and other stationary sources of mercury emissions including hazardous waste combustors. The projects focus on understanding issues related to speciation of mercury and fundamentals of sorption capture; both being necessary to develop effective control technologies, as well as experimental work on: 1) mercury speciation, characterization, and control in high and low temperature environments; 2) advanced multi-pollutant sorbents for mercury and acid gas capture; and 3) capture mechanisms for carbon-based sorbents.
.    Community-Based Risk Communication -- This project supports continuation of an ongoing cooperative agreement with the State of Wisconsin that determines how women of child-bearing age from ethnically diverse populations obtain and utilize risk communications regarding mercury contamination/health risks of non-commercial fish consumption. FY1999 funding supports an intervention study to determine if mercury intakes can be reduced through risk-reduction strategies tailored for women from ethnically diverse groups. An important component of this project is the analyses of hair samples to determine long-term mercury exposures among ethnically diverse groups. The subgroups selected will include persons with high intakes of non-commercial fish and seafood.
.    NHANES IV-Mercury Biomonitoring -- This project will improve information on occurrence of hair and blood mercury levels in the U.S. population. Mercury exposures integrated over time can be assessed through biological monitoring based on hair and blood mercury concentrations permitting EPA to refine estimates of human exposure to methylmercury based on diet and lifestyle.
.    Continuous Emissions Monitoring for Speciated Mercury -- The focus of this project is to assess comparability of results of currently available monitoring equipment that determines concentration of speciated mercury in diverse environmental media. Availability of methods for analyzing speciated mercury in environmental media will improve evaluation of estimates of source contributions.
.    Mercury Treatment Technologies -- These projects are directed at improving control technologies for hazardous waste combustors. Included are testing to evaluate both low-cost retrofit options especially for cement kilns and industrial boilers that burn mercury-bearing hazardous waste and development of technologies other than retorting and recovery to permanently treat mercury-containing hazardous wastes.
.    Testing of Continuous Emissions Monitors (CEM) for Mercury Emitted from Hazardous Waste Combustors -- To support rulemaking to set MACT emission standards for hazardous waste combustors, additional performance tests of CEMs for mercury will be conducted. The first round of testing revealed that the CEMs devices that were tested need additional engineering and then additional field testing to provide sufficient performance data to finalize the 1996 proposal to require mercury CEMS at hazardous waste combustion facilities.
.    State-of-the-Science Workshop on Mercury -- With increased emphasis on the prevention, control, and elimination of mercury pollution, a multi-day "State-of-the-Science" workshop to address current knowledge and future needs relating to mercury releases to the environment will be conducted. It is designed to focus on recent and ongoing research conducted by the Agency, as well as mercury research activities being conducted by others in academia, government, and the private sector. Proceedings from the workshop will be prepared and published. The workshop would be targeted at participants in NAFTA (i.e., Canada, the United States, Mexico) and will focus on domestic and cross-border issues. Target Date: Spring 1999

In addition, the Agency is proposing to fund investigator-initiated grants that are responsive to a "Request for Applications" (RFA) entitled, "Mercury: Transport and Fate Through a Watershed." This RFA is for grants to support fundamental research on mercury fate and transport in the environment and levels of methylation. This project is on an accelerated schedule in order to support OAR, OW, OSWER, and Office of Prevention, Pesticides, and Toxic Substances (OPPTS) regarding their need for new data in this area. ORD will solicit fundamental research on the complex chemical and physical transformations and movement of mercury through the environment. Because of the needs identified in the Mercury Study Report to Congress and other recent Agency reports related to mercury issues, this mercury solicitation has been accelerated in order to more quickly meet the needs of the Agency programs. The outcome of this research will increase our ability to trace mercury from its entrance into the ecosystem through its biogeochemical cycling to the concentration of methylmercury in fish tissue. This will promote the development of risk management strategies based on sound science.

Mercury Research Strategy

As previously discussed, OAR, OPPTS, OSWER, and OW are all faced with addressing mercury as part of their regulatory and voluntary programs. The need for mercury research is specifically identified in the Clean Water Action Plan - Restoring and Protecting America's Waters. ORD is committed to the preparation of a comprehensive, multi-year strategy for mercury research addressing the most pressing mercury research needs of the Agency as part of the action plan.

As described previously, the Mercury Study Report to Congress and other reports (e.g., Great Waters Second Report to Congress - June 1997, Utility Air Toxics Report to Congress -- February 1998), initiatives, action plans, etc. have identified research needs. However, particular documents were prepared to meet a specific charge. For example, the Mercury Study Report to Congress primarily dealt with air emissions as a source of mercury and did not address releases of mercury to water. Although the broad research questions posed in the Report apply to many source categories, it is useful to consider all mercury sources in an overall EPA Mercury Research Strategy. The research strategy is envisioned to be a comprehensive document that encompasses a discussion of current and planned research activities and addresses the long-term research needs of the Agency. The strategy will: 1) build on the research work undertaken in the FY1998/FY1999 time frame, 2) help to focus the research needs included in future mercury research initiatives, and 3) identify data that will be needed by EPA to make regulatory decisions and support EPA programs and regions in the period 2003-2005 and propose broad research initiatives/strategies that will close these data gaps between now and 2003-2005. The research strategy identifies needed research on assessing and managing risks from mercury, and supports EPA's Program Offices and Regions by identifying scientific and technical data and information that will assist them in addressing mercury's effects on human and wildlife health. The research strategy was prepared based, in large part, on the research needs identified in the Mercury Study Report to Congress. The general research themes for mercury are:

  • Hazards of Mercury/Methylmercury to Human Health
  • Ecological Effects of Mercury/Methylmercury
  • Modeling and Monitoring of Environmental Media for Mercury
  • Human and Wildlife Exposures to Methylmercury through the Aquatic Food Web
  • Control Technologies for Combustion Sources of Mercury
  • Controls for Non-Combustion Sources of Mercury
  • International Issues and Transboundary Distribution of Mercury/Methylmercury
  • Risk Communications on Mercury/Methylmercury

The Agency's draft Mercury Research Strategy is currently undergoing internal EPA review. This critical step allows EPA programs and regions to review and comment to both assure that Agency-wide concerns, needs, and issues are addressed and to identify any possible discrepancies, inaccuracies, or errors in the draft document. After internal Agency review, the comments received as a result of that review will be addressed and, if appropriate, incorporated in a revised draft in preparation for the start of external Agency review. The external review draft will be subjected to peer review and public comments, including a related effort to elicit review comments from known stakeholders and interested parties, as well as the other Federal agencies who have been EPA's partners in various mercury-related activities. The external draft will be peer reviewed by an independent expert scientific review panel. External review is expected to begin in November 1998. Following review of all comments from both the expert science panel review and as a result of public review, the draft will be revised to reflect incorporation of those comments, as appropriate. The goal of a final Mercury Research Strategy by Spring 1999 is essential in order for the Strategy to have effective input into EPA's future mercury research initiatives.

Interagency Cooperation to Address Common Mercury Concerns and Coordinate Activities

During the course of the development of the Mercury Study Report to Congress, many Federal agencies and departments were involved in key aspects of the Report. In addition, during the review and comment phase, scientific experts in these Agencies peer reviewed the draft document and provided useful comments. The next step in this continuing dialogue and cooperation in the Federal community on mercury science issues will be an upcoming workshop: "Scientific Issues Relevant to Assessment of Health Effects from Exposure to Methylmercury" on November 18-20, 1998 to be held in Raleigh, North Carolina. The meeting is being organized by the Committee on Environment and Natural Resources and the Office of Science and Technology Policy--The White House, and chaired by the National Institute of Environmental Health Sciences. Representatives from other key agencies are attending and participating including the following:

  • Environmental Protection Agency
  • Centers for Disease Control and Prevention
  • Agency for Toxic Substances Disease Registry
  • Food and Drug Administration
  • Department of Health and Human Services
  • National Oceanic and Atmospheric Administration
  • Office of Science and Technology Policy
  • Office of Management and Budget

The goal of the workshop is to discuss and evaluate the major epidemiologic studies associating methylmercury exposure with an array of developmental measures in children. Subsequently, the product of the workshop should facilitate agreement on risk assessment issues. The major studies being considered are those which have examined populations in Iraq, the Seychelles, the Faeroe Islands and the Amazon along with the most relevant animal studies for estimating human risks.

While there is no doubt that some issues will remain unresolved and further research will be recommended, the EPA is committed to a timely review of its current position regarding levels of exposure to mercury which are likely to be without appreciable risk for sensitive members of the population (fetus and infants) once Workshop conclusions and recommendations have been received.

The public is invited to attend the meeting as observers. The only limitation on public attendance is space availability. In addition, a public comment session will provide the opportunity for additional views and comments. Oral presentations will be limited to 5 minutes in length to allow for a maximum number of presentations. For more information on the Workshop please see the preliminary program attached to this testimony.


EPA has been actively engaged in the assessment of the health and ecological effects of mercury exposure for many years. While the scientific community knows a lot about the human health and ecological effects of mercury and mercury exposure, and has agreed that mercury is an important environmental problem, the development of the multi-volume 1997 Mercury Study Report to Congress provided an opportunity to integrate the years of work by the EPA, other Federal agencies, academia and the private sector into a comprehensive report on the state-of-the- science. The Agency has viewed its work on the health and ecological assessment of mercury as an iterative process that proceeds through assessment, research and data collection, refined assessment, etc. The Report gave substantial impetus to this process. ORD has responded with a targeted mercury research program and the development of a comprehensive, multi-year mercury research strategy. It is important to note, that as the Agency has developed its work on mercury related issues, it has continually coordinated its efforts with colleagues in other Federal agencies and departments, applied stringent scientific peer review, and benefitted from public input.

Mr. Chairman, this concludes my written statement. I would be happy to answer any questions that you might have.

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