Availability of a Hexachlorobiphenyl Isomer to Benthic Amphipods from Experimentally Contaminated Natural Sediments

Abstract

The present study was designed to determine the availability of radiolabeled 2,4,5,2′,4′,5′-hexachlorobiphenyl (HCBP) to benthic amphipods from experimentally contaminated natural sediments. Amphipods accumulated HCBP primarily by direct uptake from water as a function of exposure time. However, organisms that were directly exposed to the sediments had consistently higher (2.3 to 10.8×) HCBP concentrations than did organisms exposed only to the sediment-desorbed residues in the water. Experimental results demonstrated that the substrate organic matter content and particle size affected the concentrations of HCBP in the water and, in turn, in the organisms. The removal of sediment organic matter enhanced HCBP accumulation by both substrate-exposed and water-exposed organisms. Amphipods accumulated the least HCBP when exposed to silt-clay particle size fractions which contained organic matter. The substrate particle size was less important than the organic content in determining HCBP availability to the amphipods.