Report 1 of the Council on Science and Public Health (I-06)

Mercury Pollution

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Summary

Objective.  To review the major anthropogenic (human-caused emissions) sources of mercury (Hg) in the United States, the mobility of environmental mercury, and actions taken by the Environmental Protection Agency (EPA) and the U.S. government to address these issues and reduce the population exposure burden. 

Methods.  English-language reports were selected from a MEDLINE search of the literature from 1995 to 2006 using the search terms mercury/*analysis, in combination with air pollutants, environment or environmental monitoring, and the text terms regulation or emission.  In addition, the Web sites of the EPA, Government Accounting Office, National Resources Defense Council, and the Mercury Policy Project were searched for relevant information.

Results.  Release of Hg from the burning of fossil fuels, incineration of medical and municipal waste, chlor-alkali plants, and other sources resulting from human activity have increased the rate of Hg release into the environment.  Anthropogenic emission from coal-fired electric power-generating facilities, chlor-alkali production, waste incineration, and other industrial activities now account for approximately 70% of the 5,500 metric tons of Hg that are released into the earth’s atmosphere annually. Once in the environment, interconversion between the different forms of Hg occurs.  Atmospheric deposition tends to be greater in areas closer to emission sources and in locations with more rainfall, setting up a scenario where local and regional sources can create “hot spots” of relatively high Hg deposition.  In an effort to address mercury emissions in this country, the EPA promulgated the Clean Air Mercury Rule (CAMR), which implements a so-called “cap-and-trade” system for power plant emissions of mercury.  On March 10, 2005, in a separate but related action, the EPA issued the Clean Air Interstate Rule (CAIR), intended to reduce air pollution that moves across state boundaries.  This rule is intended to cap emissions on sulfur dioxide and nitrogen oxides from power plants in 28 eastern states and the District of Columbia.  Much of the putative benefits ascribed to CAMR actually derive from control technologies mandated by CAIR.  The approach advocated by CAMR could allow hot spots of local deposition to continue unabated.

Conclusion.  Mercury is a global pollutant, a major contaminant in the marine food supply, a serious neurotoxin, particularly in the developing fetus, and possibly a promoter of cardiovascular disease.  Man-made emissions and manufacturing processes account for more than half of the annual global mercury burden, with significant variation among countries and continents of the world.  The United States is the first country to regulate the major remaining source of uncontrolled mercury emissions (ie, coal-fired electricity generating plants), although some states have gone substantially further in moving to reduce Hg emissions.  While the market-driven approach taken by the EPA will reduce mercury emissions over the next three decades, more could be done immediately by using existing control technology, thus minimizing the potential for certain local and regional citizenry to continue to bear a disproportionate exposure burden.  The United States opposed a binding international treaty on mercury, but is cooperating in a voluntary manner with other countries to address several aspects of the mercury burden.  Further progress is needed in reducing the use of mercury in manufacturing and other devices. The development of economically feasible mercury control technologies should help accelerate regulatory-based, as well as voluntary reductions in Hg emissions.

RECOMMENDATIONS (Adopted AMA Policy and Directives)

The following statements, recommended by the Council on Science and Public Health, were adopted by the AMA House of Delegates as AMA policy and directives at the 2006 AMA Interim Meeting: 

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