W. Waynon Johnson

Toxaphene and DDTR (DDT plus metabolites), both exceeding 10 ppm wet weight, were found in all samples of fish collected from 9 locations on the Yazoo, Mississippi, National Wildlife Refuge. Concentrations were highest in aquatic systems receiving direct inflow from areas draining agricultural land, and lowest in areas receiving only backwater overflow or local runoff. Residue levels of toxaphene and DDTR were high enough to threaten fish-eating wildlife. Installation of flood control structures around the northern perimeter of the refuge may reduce the inflow of contaminants that now...

Trace elements (As, Cd, Cr, Cu, Hg, Pb, Se, and Zn) were measured in fish, clams, and sediment in 1982 to determine whether the effluents from 2 abandoned battery salvage operations were contaminating the Chipola River, Florida. Concentrations of the metals were generally low, but tended to increase downstream from plant sites. Elevated concentrations may reflect residual contamination from the battery salvage operations as well as increased land-use development and proximity to major highways. Concentrations of trace elements in samples of biota and sediments demonstrated no serious...