Mixed function oxidase dependent biotransformation of polychlorinated biphenyls by different species of fish from the North Sea

Mixed function oxidase (MFO) dependent biotransformation of polychlorinated biphenyls (PCBs) was measured in three different fish species from the Nor th Sea. Liver microsomes of plaice (Pleuronectes platessa), dab (Limanda li manda) and cod (Gadus morhua) were isolated and incubated with different PC B congeners. Metabolites of PCBs were identified as monohydroxylated PCBs. Hydroxylation took place in meta- or para-position of the PCB molecules, pr eferential in para-position. Metabolization and metabolic rates depended on the substitution pattern of PCBs and the degree of chlorination. Biotransf ormations were also species dependent. The flatfish dab and plaice exhibite d higher metabolic rates than cod (C) 1999 Elsevier Science Ltd. All rights reserved.