Summary

Description

The U.S. Fish and Wildlife Service conducted this study because of the distinct possibility that DDTR DDT and its metabolites and other organochlorine pesticides were above concern levels in fish and aquatic oriented wildlife on the Hillside National Wildlife Refuge. There was also a belief that organochlorine pesticides were disrupting the endocrine systems of fish and wildlife, and that they may be resulting in toxic effects to the benthic macroinvertebrate community. DDTR concentrations were above concern levels in only two of the twenty one fish samples, which do not indicate a problem. Toxaphene concentrations in nine of the twenty one fish samples were above the predator protection level. This finding indicates that a toxaphene contamination problem occurs on the refuge. We cannot conclude at this time whether the polychlorinated biphenyls PCBs concentrations detected in the fish samples are adversely affecting mink on the refuge. Additional fish samples should be collected and analyzed for the more toxic PCB congeners to answer this question. Three of the raccoon tissue samples contained elevated concentrations of DDTR; however, these levels were well below concern levels mentioned in the literature. Analyses of the fish blood plasma indicated that endocrine disruption was not occurring in fish collected from the refuge. The raccoon blood plasma samples thawed in route to the laboratory, therefore, additional raccoon blood plasma samples should be collected in the future and analyzed. The bioassessment on Black Creek did not indicate that contaminants were adversely affecting the benthic macroinvertebrate community. Recommendations are provided in the report to address problems and concerns identified by this investigation.