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Water: Mercury Maps

Mercury Maps

Linking Air Deposition and Fish Contamination on a National Scale


Mercury Maps is a tool that relates changes in mercury air deposition rates to changes in mercury fish tissue concentrations, on a national scale. Mercury Maps can be used to help identify those waterbodies expected to attain state water quality standards as a result of air deposition reductions, or to assist in Total Maximum Daily Load (TMDL) analyses for individual or multiple watersheds.

Fact Sheet— A summary on the background, environmental and public health benefits, and technical approach of the project.

Overview Slides—the content of a slide show presenting a quick overview of the Mercury Maps project.

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Peer Reviewed Final Report—Mercury Maps: A Quantitative Spatial Link Between Air Deposition and Fish Tissue (PDF) (61 pp, 1.6MB) (September 2001) A report detailing the derivation of the Mercury Maps model as well as the selection and use of mercury source data layers. Peer-reviewed by EPA scientists, the report incorporates their comments and includes a response-to-comments document in the Appendix.


  • BASINS: Better Assessment Integrating Point and Nonpoint Sources
    A number of the national data coverages used in Mercury Maps were derived directly from this GIS and environmental modeling program.
  • National Listing of Fish Advisories (NLFA):
    The source of the 69,000 record fish tissue mercury database used in this project.
  • Fish Tissue Human Health Water Quality Criterion for Methylmercury
    The criterion is a concentration of methylmercury in fish that is expected to be without appreciable risk to human health. States and tribes may use the criterion as the basis for establishing water quality standards. Governments may also use the criterion as the basis for establishing fish advisories.

For more information on Mercury Maps, contact basins@epa.gov.

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