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Organochlorine pesticides and PCBs in stream sediment and aquatic biota : initial results from the National Water-Quality Assessment Program, 1992-1995

Water-Resources Investigations Report 2000-4053

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Abstract

One of the goals of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey is to assess the status and trends in the nation's water quality and to understand the natural and anthropogenic factors that affect water-quality conditions. This report summarizes the occurrence and distribution of 33 organochlorine compounds in fluvial bed sediment and aquatic biota (whole freshwater fish and freshwater bivalves) sampled by NAWQA investigations between 1991 and 1994. These include historically used insecticides (DDT and metabolites, chlordane and its various components, and dieldrin), some currently used pesticides (permethrin and dacthal) and some industrial chemicals and byproducts (PCBs and hexacloro- benzene). Samples were collected at approximately 500 sites in 19 large hydrologic basins throughout the United States. Contaminant levels in bed sediment and aquatic biota are summarized, first on a national basis, and then by land-use classification (for example, urban, cropland, pasture and rangeland, and forest). Nationally, detection frequencies are highest in sediment and biota for the more persistent organochlorine compounds: total DDT, total chlordane, dieldrin, and total PCBs. Organochlorine compounds were detected more frequently in whole fish than in bivalves or bed sediment. Organochlorine pesticide concentrations were relatively high in agricultural regions with histories of high use. The highest organochlorine compound concentrations in both sediment and biota generally were associated with urban areas. Some organochlorine concentrations in sediment exceeded guidelines for the protection of aquatic organisms. A screening-level comparison of measured organochlorine concentrations in whole fish was made with human health guidelines that are applicable to edible fish. This comparison indicates stream sites at which additional sampling of game fish fillets may be warranted, depending on local patterns of fish consumption. A comparison of current national contaminant levels with previous studies of this scope suggests a gradual decrease in organochlorine contaminant levels, at least in fish.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Organochlorine pesticides and PCBs in stream sediment and aquatic biota : initial results from the National Water-Quality Assessment Program, 1992-1995
Series title:
Water-Resources Investigations Report
Series number:
2000-4053
Year Published:
2000
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Sacramento, CA
Description:
viii, 88 p.
Country:
United States
Additional Online Files(Y/N):
N