CONTAMINATION AND CORRELATION WITH TOXICITY OF SEDIMENT SAMPLES FROM THE SKAGERRAK AND KATTEGAT

The pollution state in the Skagerrak and Kattegat was investigated by determination of pollutant concentrations and toxicity of sediment sam ples from 11 stations in the area. A comparison was made with the sedi ment from a reference site near the Faroe Islands. Polycyclic aromatic hydrocarbons (PAH) and organochlorines were determined in whole sedim ent and heavy metals and ammonia were analysed in filtered pore water. Toxicity was bioassayed in whole sediment with Nitocra spinipes and D aphnia magna, in pore water with Mytilus edulis larvae and in solvent extracts from sediment with tests measuring etoxyresorufin-O-deethylas e (EROD) activity in Oncorhyncus mykiss and rate of denitrification. S ites close to Goteborg and in an area from the Oslo fjord to the Norwe gian Trench were most polluted. Sediment from the Faroe Islands was le ast polluted and also least toxic. Multivariate statistical analysis i ndicates that the different tests were sensitive to different kinds of pollutants. Effects on mussel larvae correlated strongest with the oc currence of ammonia, manganese, cadmium and PAHs, Nitocra with alpha-h exachlorocyclohexane (HCH) and p,p'-DDD, Daphnia with arsenic and gamm a-HCH, fish EROD activity with benzo[ghi]perylene and unknown compound s associated with organic carbon, and denitrification with chlordanes, dieldrin and a few PAHs. The results indicate that sampling sites clo se to Goteborg are so polluted that harmful effects on the ecosystem p robably occur.