Organochlorine pesticides and polychlorinated biphenyls in livers of cod from the southern Baltic, 1981.

471 samples of livers of cod netted in July 1981 in seven fishing grounds in the southern part of the Baltic were analysed for polychlorinated biphenyls (PCBs), DDT and its metabolites (DDE and DDD), hexachlorobenzene (HCB), and isomers of benzenehexachloride (alpha-, beta-, gamma- and delta-BHC). Polychlorinated biphenyls resembling Chlopten A 60 were the predominating pollutants and their level ranged from trace amounts to 79 mg/kg. In the individual wet cod livers sigma DDT level ranged from 0.22 to 15 mg/kg. alpha-BHC, gamma-BHC and HCB levels ranged from not detectable levels to 0.29, 1.1 and 0.42 mg/kg, respectively. beta-BHC was detectable in most of the samples in trace amounts and delta-BHC was undetected. The levels of HCB, DDT and analogues and PCBs in the cod livers correlated with the length of the fish. The residue levels of sigma DDT in cod livers declined. The larger cod contained in their livers substantial levels of PCBs, and also of sigma DDT. However some local differences in pollution pattern were observed. The livers of cod from the Southern Baltic are relatively highly contaminated with these substances and the use of these products for human consumption is still questionable.