APPLICATION OF TOXICITY IDENTIFICATION EVALUATION TECHNIQUES TO PORE-WATER FROM BUFFALO RIVER SEDIMENTS

To identify contaminants responsible for toxicity of sediments from th e Buffalo River, toxicity identification evaluations (TIEs) were condu cted with interstitial (pore) water from several sites. Initial toxici ty of the samples was determined using fathead minnows (Pimephales pro melas) and the cladoceran Ceriodaphnia dubia, and TIE analyses were co nducted with the most sensitive of the two species at a particular sit e. Fathead minnows were more sensitive than C. dubia to pore water fro m five surficial samples, and TIE results suggested that under our tes t conditions ammonia was the primary toxicant to the fish. In contrast , C. dubia were more sensitive than fathead minnows to pore water from a sample comprised of deeper sediments at a site that corresponded wi th one of the surficial samples. Pore water from the deep sediment als o was significantly more toxic to both species than the five surficial samples. In this instance, metals (predominantly copper, zinc, and le ad) appeared to be most important in determining pore water toxicity t o the cladoceran. Based on these analyses, there appear to be both qua ntitative and qualitative differences in toxicity/toxicants between su rficial and deep sediments in the Buffalo River. This is an important consideration in identifying possible remedial strategies involving re moval/management of existing (surficial) sediments.