Survey of Fish Contamination in Small Wadeable Streams in the Mid-Atlantic Region
United States Environmental Protection Agency Office of Research and Development
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in 1993 and 1994, fish tissue samples were collected from first, second and third order streams in the Mid-Atlantic Region of the United States. The tissue samples were prepared from whole fish from prioritized lists of Small Target Species and Large Target Species. The two types of samples were analyzed for 56 contaminants, of which 22 had median values that were above the detection limits for at least one category of fish. For this report, the data analyses were conducted in order to determine 1) exposure to contaminants, 2) the magnitude of exposure, and 3) the location of the sites which exceeded toxicological benchmark values. All sites from which samples were taken showed exposure to at least one contaminant. In order to determine the magnitude of this exposure, no observed adverse effects level (NOAEL) benchmark values for 16 of the analytes were used. These NOAEL benchmark values are estimates of the greatest concentration of contaminants at which it is unlikely that the belted kingfisher (Megaceryle alcyon) would suffer adverse effects from consumption. These NOAEL benchmark values were then compared to the concentration of contaminants found in Small Target Species tissue sampled at each site. Maps were generated which showed the locations of the sites that exceeded the NOAEL benchmark values. Seventy sites (100%) exceeded at least one NOAEL benchmark value and twenty two sites (31.4%) exceeded four or more NOAEL benchmark values. The number of sites exceeding multiple NOAEL benchmark values suggests a comprehensive study of fish tissue contaminants is warranted for the region.