Extractable organohalogens (EOX) in sediment and mussel tissues from the Kentucky Lake and Kentucky Dam Tailwater, USA

Abstract

Extractable, organically bound chlorine (EOCl) concentrations in environmental samples have been used as one of the measures of pollution by chlorinated organics. Extractable organohalo‐gens (EOX = EOCl + EOBr + EOI) were measured in surface sediments and mussel tissues collected at selected locations in the Kentucky (KY) Lake and KY Dam Tailwater, USA. In sediments, EOX concentrations ranged from 0.22 to 0.90 μgg ‐1 dry wt. The sediment EOCl concentrations recorded in Kentucky Lake and KY Dam Tailwater were lower than those reported for sediments from industrial effluent contaminated sites. In freshwater mussel tissues, concentrations varied between 17.7 and 43.35 μgg ‐1 dry wt. Concentrations of EOCl measured in the tissues were comparable with those reported in fish and shellfish from PCBs and other chlorinated hydrocarbon contaminated sites. Extractable organochlorines (EOCl) were the highest in the total EOX family followed by organobromines and organoiodines. PCBs and chlorinated pesticides constituted only a minor part (<6% in sediment and <1 % in mussel tissues) of the EOCl, indicating the presence of additional, unknown organochlorine residues in sediments and mussel tissues from Kentucky Lake and KY Dam Tailwater. Elevated concentrations of EOCl and the proportions relative to the concentrations of EOBr and/or EOI in freshwater mussel tissues suggest that historical contamination as well as recent organic contaminant put in this region may be possible source of organic halogens in the environment.