Sediments were sampled from Wheatley Harbour and Muddy Creek located along the north shore of Lake Erie in 1992 in order to carry out a laboratory biological assessment of contaminated sediments from that Area of Concern. The main objectives of the study were: 1) To describe the level of inorganic and organic chemical contamination in surficial sediments at one reference and five test locations; 2) To assess the toxicity of whole-sediments in laboratory tests using the mayfly, Hexagenia limbata (survival and growth, 21-day exposure), the midge, Chironomus tentans (survival and growth, 11-day exposure) and the juvenile fathead minnow, Pimephales promelas (survival, 21-day exposure); 3) To determine the availability of sediment-bound organic contaminants to the forage fish, Pimephales promelas after a 21 day exposure period.