|The bioaccumulation study is an outgrowth of the EPA's National Dioxin Study concerned with assessing contamination from 2,3,7,8-tetrachloro-p- dioxin (2,3,7,8-TCDD) in soil, water, sediment, and fish tissue. Phase 2 of this program involves investigation of the degree of contamination of environ mental samples by other pollutants with emphasis on organic chemicals. The University of Wisconsin-Superior (UWS) has reanalyzed fish. tissue samples collected as part of the National Dioxin Study for tetrachloro to octachloro congeners/isomers of polychlorinated dibenzo-p-dioxins (.PCDDs) and dibenzo furans (PCDFs). These congeners/isomers have toxicity equivalency factors lower than 2,3,7,8-TCDD. This reanalysis included 2,3,7,8-TCDD which-provides a comparison of these results with the previous analyses for 2,3,7,8-TCDD. The fish with greater than 0.7 ppm Hg values did not have high. 2,3,7,8-TCDD values.