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Release Date: 01/07/98
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The U.S. Environmental Protection Agency today, as requested by Congress, released its first-ever national report on the quality of sediments in the nation’s rivers and other inland and coastal waterways. The report finds that the majority of watersheds do not pose probable adverse risks but that seven percent of the surveyed watersheds are sufficiently contaminated with toxic pollutants to pose potential risks to people who eat fish from them and to fish and wildlife.
The risks posed in the seven percent of the watersheds pertain to subsistence fishers and others who fish those contaminated waters for food and do not apply to people who eat fish that are commercially available from grocery stores and restaurants.

EPA Assistant Administrator for Water, Robert Perciasepe, said, “The report confirms that contaminated sediment is a significant problem in many watersheds around the country. The report underscores the need to finish the job of cleaning up our nation's waters and to prevent their continued pollution to protect public health.”

The data show that every state has some sediment contamination and that streams, lakes and harbors can be affected. Sites where the highest levels of sediment contamination were measured tend to cluster around larger urban areas and industrial centers and in regions affected by agricultural and urban runoff.

In preparing this report, EPA assembled the largest set of sediment chemistry and related biological data ever compiled into a national database, called the National Sediment Inventory. EPA examined approximately two million records from more than 21,000 sampling stations that are located in 1,363 of the 2,111 watersheds (65 percent) in the continental United States. The locations were sampled between 1980 and 1993.

EPA classified each of the sampling stations into one of three tiers based on data recorded for that location: Twenty-six percent of the samples fell into Tier 1 - adverse effects are probable; forty-nine percent of the samples fell into Tier 2 - adverse effects are possible but expected infrequently; and 25 percent of the samples fell into Tier 3 - no indication of adverse effects. EPA classified watersheds as “areas of probable concern” if they contained 10 or more Tier 1 sampling stations and if 75 percent or more of all the sampling stations in that watershed were classified as either Tier 1 or Tier 2. This classification approach showed that 96 watersheds, or seven percent of those surveyed, are sufficiently contaminated to pose potential risk to people who eat fish and to fish and wildlife. More than two-thirds of these watersheds already have active fish consumption advisories in place.

Sediments are soils, sand and other matter that wash from land and settle on the bottom of a river, lake, bay or the ocean floor. Sediment at many sites throughout the United States was polluted years ago by chemicals such as DDT, polychlorinated biphenyls (PCBs), and mercury. These pollutants may accumulate in fish and may cause increased risks of cancer, neurological and IQ impairment in people who eat large quantities of contaminated fish. While use of these substances has been banned or restricted for many years, these chemicals can--and do--persist for many years in the sediment, and continue to be a source of concern for the environment and public health. Other chemicals that are released to surface waters from industrial and municipal discharges and polluted runoff from urban and agricultural areas continue to accumulate to harmful levels in sediments.

Over the last two decades, EPA and the states have taken a number of actions to ensure that future contamination of sediments is prevented. These measures include: imposing the strongest restrictions ever taken on incineration emissions, which can travel by air to water and be deposited in sediments; cutting discharges of toxic and hazardous pollutants in wastewater by one billion pounds per year; cleaning up contaminated sediment in hot spots in the Great Lakes basin and in major bays and coastal areas throughout the country; setting protective water quality standards to limit toxic pollutant discharges in the Great Lakes region; and reducing polluted runoff from U.S. urban and agricultural areas.

EPA has established four goals to guide future efforts to manage contaminated sediment: 1) prevent the volume of contaminated sediment from increasing; 2) reduce the volume of existing contaminated sediment; 3) ensure that sediment dredging and dredged material disposal are managed in an environmentally sound manner; and, 4) develop scientifically sound sediment management methods. Over the next three months, EPA will finalize a strategy to help the nation achieve these goals.

The national inventory of sediment quality, compiled at the request of Congress under the Water Resources Development Act of l992, was prepared in consultation with the National Oceanic and Atmospheric Administration (NOAA), the Army Corps of Engineers and other federal, state and local agencies.

Additional information on local contamination is available from EPA’s Index of Watershed Indicators on the Internet at Copies of EPA’s fact sheet (EPA 823-F-98-001) or the three-volume report: “The Incidence and Severity of Sediment Contamination in Surface Waters of the United States” (EPA 823-R-97-006, EPA 823-R-97-007, and EPA 823-R-97-008) are available from the U.S. Environmental Protection Agency, National Center for Environmental Publication and Information, 11029 Kenwood Road, Bldg. 5, Cincinnati, Ohio 45242; fax: 1-513-489-8695 or 1-800-490-9198. The fact sheet is also available on the Internet at

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