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The Great Waters Program


Information provided for informational purposes onlyNote: EPA no longer updates this information, but it may be useful as a reference or resource.
Introduction to the Issues and Ecosystems

Over the past 30 years, scientists have collected a large and convincing body of evidence demonstrating that toxic pollutants released to the air can be deposited at locations far from their original sources. Chemicals of human origin such as polychlorinated biphenyls (PCBs) and pesticides like DDT have been found thousands of miles from likely emission sources in the fatty tissues of polar bears and other Arctic animals. Fish from Siskiwit Lake, a small lake on an island in northern Lake Superior that is isolated from most human influences, are contaminated with PCBs and the pesticide toxaphene, which have no known sources on the island.

On November 15, 1990, in response to mounting evidence that air pollution contributes to water pollution, Congress amended the Clean Air Act and included provisions that established research and reporting requirements related to the deposition of hazardous air pollutants to the "Great Waters." The waterbodies designated by these provisions are the Great Lakes, Lake Champlain, and Chesapeake Bay and certain other coastal waters (identified by their designation as sites in the National Estuarine Research Reserve System or the National Estuary Program).

This atlas is written to provide basic information about the Great Waters, their water quality problems, and the issue of atmospheric deposition to aquatic ecosystems in general. For more detail, the Great Waters biennial Reports to Congress discuss current scientific understanding of atmospheric deposition and the health and environmental effects of toxic pollution, as well as EPA's programs to protect human health and the environment.

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