ORGANOCHLORINE CONTAMINANTS IN LIVER OF COD (GADUS-MORHUA) AND MUSCLE OF HERRING (CLUPEA-HARENGUS) FROM SCOTTISH WATERS

Cod and herring were sampled from the northern Clyde Sea, the outer Firth of Forth and the northern North Sea and analysed for a range of organochlorine compounds. Analysis of fish in several pools enabled the variability of the data to be assessed. The mean overall coefficient of variance was 30%. This figure was compounded from an analytical variance of 12%, and a 'field' variance related to individual fish, of 150%. Normalization to tissue lipid content was not appropriate as negative correlations were present between lipid content and contaminant loading. Simple t-tests on the data revealed significantly higher levels of chlorobiphenyls, DDT compounds and dieldrin in fish from the Clyde. With the exception of hexachlorobenzene, which was elevated in fish from the outer Firth of Forth, contaminants levels were lower and comparable in fish from the outer Firth of Forth and the northern North Sea.