Abstract

After removing contaminated sediments from a toxic waste site’s outlet stream into Brockport creek, PCB concentrations in the outlet stream dropped from 1,730 to 34,900 µg/kg in 2002 to 288 to 432 µg/kg in 2003. Concentrations are now below water quality criteria for aquatic organisms and human health. Concentrations of eight metals (Arsenic, Barium, Cadmium, Chromium, Copper, Lead, Nickel, Zinc) also decreased greatly but because of naturally high background levels several remain above water quality criteria. The benthic macroinvertebrate community at the remediated site was severely degraded by dredging but showed signs of recovery the next year. All but one of the other sites sampled above and below the outlet stream from the toxic waste site had moderately polluted or disturbed benthic macroinvertebrate communities typical of the region. No patterns of sediment toxicity (survival, growth, reproduction) were observed for Daphnia magna, Hyalella azteca and Pimephales promelas in relation to sampling locations in the waste site’s outlet stream and Brockport creek. The cleanup of the contaminated outlet stream appears to have been successful.

Key words: Toxicity testing, PCBs, metals, benthic macro invertebrates.