Distribution of selected polychlorinated biphenyls (PCBs) in brain and liver of arctic char ( Salvelinus alpinus)

Abstract

The distribution of eight polychlorinated biphenyls (PCBs) in brain and liver tissues of Arctic char (Salvelinus alpinus) was analysed 10 weeks after intraperitoneal injection. The PCBs, PCB#41, #58, #60, #99, #104, #126, #173, and #190, were selected to represent a large variation in physico-chemical characteristics. The levels of the PCBs, on lipidbasis, were 2–5 times higher in liver than in brain. In both tissues, the lower chlorinated congeners were found in highest concentrations. Structural features of the PCBs favouring rapid metabolism are thought to be unsubstituted adjacent meta and para positions. In agreement, PCB#41 and #104 are found in low levels in both tissues. Varied levels of PCB#126 in the two compartments are probably due to differences in lipid composition between brain and liver. In order to study the distribution in liver and brain, the ratio brain/liver was related to a large number of physico-chemical parameters of the PCBs. A multivariate quantitative structure-activity relationship (QSAR) shows that not only K ow is needed to describe the distribution. Other important parameters are the internal barrier of rotation and the heat of formation. Present results indicate that substitution pattern related characteristics are crucial in order to describe the distribution of PCBs in fish.