Mercury in Maine A Status Report
Report to the Joint Standing Committee on Natural Resources
February 2002
EXECUTIVE SUMMARY
Mercury can impair childhood development when pregnant women or young children are exposed to the metal at very low concentrations. Recent surveys conducted in Maine and nationally indicate that 10 - 20% of women of childbearing age have blood levels of mercury considered too high for a developing fetus.
Mercury is also toxic to wildlife, diminishing the ability of loons and potentially other species to reproduce. At current mercury levels in the environment, population modeling predicts Maine's loon population is unsustainable.
The chief pathway of both human and wildlife exposure is the consumption of fish, in which mercury in the environment becomes concentrated. Other potential human exposure pathways include residential and school/workplace exposure due to spills/breakage of mercury-added products, or due to the use of certain mercury-added products such as dental amalgam and certain consumer products (i.e., pharmaceuticals, antiseptics).
While some mercury is released to the environment from natural sources, most releases are the result of human activities. These releases are chiefly to air subsequently deposited to land or water. The mercury deposited in the northeast originates from in-state, regional, national, and global sources. In-state and regional sources historically accounted for slightly less than half (47%) of the northeast's mercury deposition.
Under the auspices of the New England Governor's Conference and the Eastern Canadian Premiers (NEGC/ECP), Maine and the other New England states committed in 1998 to a goal of 50% mercury emissions reduction by 2003. A formal assessment of whether this goal has been achieved will be prepared later in 2002, but preliminary analyses indicated that it will be achieved largely through emissions reductions from municipal waste combustors, medical waste combustors, and the closure of Maine's HoltraChem chlor-alkali facility in Orrington. Maine's contribution to these regional reductions includes an emissions reduction of 94% from its four municipal waste combustors.
In August 2001, NEGC/ECP committed to further reductions in mercury emissions, setting a 75% emissions reduction target by 2010 (as compared to the 1998 baseline). Preliminary analyses indicate the bulk of these reductions will come from coal combustion sources, sewage sludge incinerators, and the reduction of use/disposal of mercury-added products. In Maine, DEP intends to determine the quantity of emissions from its three known industrial users of coal, and evaluate whether such emissions comply with upcoming limits imposed by current state law and whether additional limits may be appropriate. In addition, DEP intends to achieve further reductions associated with mercury-added products through a variety of regulatory, educational, technical assistance, municipal grant and other mechanisms specified in this report.
As noted above, slightly more than half of mercury deposition in the northeast comes from sources outside of the region. Accordingly, DEP will continue to devote significant attention, individually and through its various state regional and national environmental associations, to addressing the national and global aspects of mercury in the environment. Toward this end, DEP will pursue national and international policies that include the following five elements:
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Aggressive reductions of mercury emissions from coal-fired power plants and other significant sources;
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Minimize use of mercury in products;
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Creation of a stewardship approach for safely managing excess mercury supplies;
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Development and deployment of a sound technology for the safe disposal of mercury wastes; and
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Development and implementation of a strategy for substantially decreasing the global supply and demand for mercury.
Finally, DEP will continue its research and data gathering activities aimed at better understanding the dimensions of the challenge posed by mercury in the environment. Such activities will include continuation and enhancement of the Mercury Deposition Network instate and within the region so that historical/geographic trends can be identified and the impact of local, regional, and other emissions reductions efforts can be ascertained. Other state research activities contemplated as funding allows include additional work on potential wildlife impacts of mercury in Maine, collecting emissions data and updating regional emission inventories through NEGC/ECP, characterizing the types of commercial and industrial boilers burning residual oil, and evaluating the effectiveness of the mechanisms used to communicate fish advisories to those Maine citizens particularly at risk.
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