Temporal trends of organochlorine concentrations in cod-liver oil from the southern Baltic proper, 1971–1989

Abstract

Concentrations of PCBs, DDTs, HCHs (BHCs), HCB, aldrin, dieldrin, chlordanes, heptachlor, and heptachlor epoxide were determined in cod-liver oil samples collected from the southern part of the Baltic proper during 1971–1989 for understanding the long-term changes in residue levels and the present status of contamination. There has been a rapid decline in DDT concentrations from 1974 until the present. PCBs, HCB, aldrin, and dieldrin tended to decrease at a very slow rate while HCHs showed a steady state in their time trends. Unlike the pattern observed for other organochlorines, chlordane compounds depicted an upward movement until the early 1980s and then declined. No clear trends could be discerned for heptachlor and heptachlor epoxide. Higher contamination of organochlorines in the present study area might be an indication of the continuous input of these chemicals from eastern Europe and a slower clearance rate in the Baltic ecosystem.