Mercury In the Environment
In 2001, ECOS and other partners founded the Quicksilver Caucus (QSC) to pool resources, and to explore and pursue methods for reducing mercury in the environment. For years, this work has been supported in part by a series of grants from the U.S. Environmental Protection Agency.
Mercury is a naturally occurring trace element found in air, water and soil. However, various human activities are widely dispersing larger amounts of mercury into the environment than otherwise would occur naturally. Thousands of household, commercial and industrial processes can release mercury into the environment. Mercury can enter waterbodies through direct discharge, non-point runoff or from atmospheric deposition, which is the most significant source. Mercury in aquatic systems when converted by microorganisms into its organic form, methylmercury, is toxic. Methylmercury bio-accumulates in the aquatic food chain and poses significant threats to humans and animals that consume the fish.
Mercury is a dangerous neurotoxin which can render deleterious effects on human mental development and the nervous system. Mercury poses a particular threat to children and the unborn fetus. The population at the highest risk of mercury-related developmental problems is children of women who consumed large amounts of fish and seafood during pregnancy. Blood mercury analyses in the 1999-2000 National Health and Nutrition Examination Survey (1999-2000 NHANES) for 16-to-49 year old women showed that approximately 8% of women in the survey had blood mercury concentrations greater than 5.8 ug/L (which is a blood mercury level equivalent to the current RfD). Based on this prevalence for the overall U.S. population of women of reproductive age and the number of U.S. births each year, it is estimated that more than 300,000 newborns each year may have increased risk of learning disabilities associated with in utero exposure to methylmercury. As a result, 49 states and the Food and Drug Administration have adopted public health advisories throughout the country due to mercury contamination.
Important sources of mercury depend on your location: there is a much higher contribution of mercury from municipal waste incinerators than coal-fired utility boilers in Florida, and a higher contribution from utility boilers in the Great Lakes. However, mercury is volatile and can be transported thousands of miles by air currents before being deposited. Thus, mercury in the environment is a national, as well as international, issue.
Currently, states are required to address pollutants of concern in their watersheds, and then take steps to control and limit these pollutants. This is required by the Clean Water Act through development of total maximum daily loads (TMDLs). This is enforced by both rule and by court orders. Unfortunately, too many watersheds are adversely affected by mercury, without any significant source of mercury being present in the watershed. In these cases, mercury is coming from the air, a phenomenon known as "air deposition." Such a source, however, does not exempt states from the TMDL requirements. As can readily be seen, states must try to address interstate and international sources of mercury in order to meet the TMDL requirements of the Clean Water Act, and to comply with related court orders.
ECOS has joined with other state environmental association leaders in the Quicksilver Caucus (QSC) to collaboratively develop holistic approaches for reducing mercury in the environment. Caucus members who share mercury-related technical and policy information include the Environmental Council of the States (ECOS), the Association of State and Territorial Solid Waste Management Officials (ASTSWMO), the National Association of Clean Air Agencies (NACAA), the Association of Clean Water Administrators (ACWA), the Association of State Drinking Water Administrators (ASDWA) and the National Pollution Prevention Roundtable (NPPR).
The QSC works collaboratively to explore ways to reduce mercury pollution, reduce mercury use in products, and to better manage mercury in products. The QSC's current work is supported by a grant from the U.S. Environmental Protection Agency. Click here (and scroll down to the "Mercury" section) to see a list of current QSC projects, and click here to view the QSC webpage and view QSC work products.