Organochlorine compounds in marine organisms from the international North Sea incineration area

Samples were taken in January and May 1988, May 1989 and in January 1990 to analyse organochlorine residues in organisms from an incineration area northwest of the Dutch coast, which had been active since 1979, and from reference areas in its vicinity. The samples consisted of dab (Limanda limanda), whiting (Merlangius merlangus) and the benthic organisms hermit crab (Pagurus bernhardus), swimming crab (Linocarcinus holsatus), whelk (Buccinum undatum), helmet crab (Corystes cassivelaunus), sea mouse (Aphrodite aculeata) and sea urchin (Psammechinus miliaris). Tissues of these organisms were analysed using capillary gas chromatography. The predominant residues were congeners of polychlorinated biphenyls (PCBs) and the second largest proportion was represented by the sum of p,p'-DDT and its metabolites. Concentrations of DDT were below the detection limit. Furthermore, residues of the following substances were found: pentachlorobenzene (QCB, formerly PeCB), hexachlorobenzene (HCB), octachlorostyrene (OCS) and isomers of hexachlorocyclohexane (alpha-HCH and gamma-HCH = lindane). Elevated concentrations of OCS from the incineration area were found in dab and benthic organisms in 1988, 1989 and 1990, and also in whiting in 1989. When comparisons were made throughout the North Sea, significantly elevated concentrations of OCS were detected only in the livers of dab from the incineration area. Three of the five invertebrate species from the 1988 sampling showed significantly elevated concentrations of HCB. In 1989 contamination of HCB in benthic organisms, dab and whiting in the incineration area was significantly higher compared with the reference area. Regional differences for HCB in organisms were less consistent than for OCS, which was regularly found in higher concentrations in organisms from the incineration area compared with those from neighbouring stations. It is therefore discussed whether elevated levels of OCS in organisms from the North Sea incineration area can be taken as an indication of incomplete combustion resulting in the accumulation of chlorinated hydrocarbons in marine organisms. The incineration was terminated in February 1991.