Organochlorine compounds in the Gulf of Bothnia: sediment and benthic species

Surface sediment, amphipods (Monoporeia affinis), isopods (Saduria entomon) and fourhorn sculpins (Oncocottus quadricornis) were collected at two coas tal stations in the Gulf of Bothnia, one in the Bothnian Bay and the other in the Bothnian Sea. The objective was to study the concentrations, composi tion profiles, bioaccumulation features and spatial differences of organoch lorine compounds such as hexachlorocyclohexanes (HCHs), DDTs, hexachloroben zene (HCBz), chlordanes (CHLs), dieldrin, Mirex and polychlorinated bipheny ls (PCBs). All groups of compounds were found in every sample investigated, with the exception of Mirex that was not detected in the sediment samples. The concentrations for e.g. PCBs and CHLs ranged from 700 to 2400 and 70 t o 400 ng/g lipid in the specimens. For the corresponding sediments the resu lts were 9.0-9.3 ng/g dw for PCBs and 0.54-0.57 ng/g dw for CHLs, respectiv ely. Bioaccumulation differences between the species with regard to both de gree of and type of compound were observed. The highest accumulation potent ial was found for the cyclodiene compounds including CHLs and Mirex in isop od. Finally, there were only small concentration and bioaccumulation differ ences between the two stations. (C) 2000 Elsevier Science Ltd. All rights r eserved.