Publication Abstract

Concentration dependent changes of PCB patterns in five species of fish-eating mammals in relation to uptake from food and biotransformation capacity

Concentration dependent changes of PCB patterns in five species of fish-eating mammals in relation to uptake from food and biotransformation capacity

J.P. Boon, J. Van Der Meer, C.R. Allchin, R.J. Law, J. Klungsoyr, P.E.G. Leonard, H. Spliid, E. Storr-Hansen, D.E. Wells and C. McKenzie

As an initiative within the Marine Chemistry Working Group (MCWG) of the International Council for the Exploration of the Sea (ICES), datasets on PCB concentrations in fish-eating mammals from different laboratories were combined for statistical treatment. Goal was to create a large dataset to test and further refine a kinetic model describing patterns of PCBs in lung-respiring predators in terms of uptake from food and biotransformation capacity. In the model, individual chlorobiphenyl congeners are divided into six different metabolic groups on the basis of the location of the vicinal hydrogen atoms and the number of ortho-chlorine atoms. Datasets involved 2 phocid seals species (harbour seal, grey seal), the otter and two cetacean species (harbour porpoise and common dolphin). Principal component analysis was used in the form of covariance bi-plots. The results of different laboratories with regards to single species merged without problems. As such the intercalibration exercises previously carried out within the framework of the MCWG has been essential to the success of the project. Clear differences in PCB patterns were observed between the species. In general, the ability to metabolise congeners with unsubstituted ortho- and meta-positions and 1 ortho chlorine atom increased in the order otter < cetaceans < seals. Biotransformation of this type of congeners in probably mediated by enzymes of the cytochrome P450 IA subfamily. In contrast, the ability to metabolise meta-, paraunsubstituted congeners with two ortho-chlorine substituents increased in the order cetaceans < seals < otter. Metabolism of this type of congeners is probably mediated by cytochrome P450 213 isozymes. Evolutionary, this subfamily of isozymes is assumed to have gained importance when animals moved from water to land and therefore had to develop enzyme systems able to detoxify poisonous compounds produced by higher terrestrial plants. The order of biotransformation rates for this type of congeners is in agreement with this hypothesis.

Reference:

J.P. Boon, J. Van Der Meer, C.R. Allchin, R.J. Law, J. Klungsoyr, P.E.G. Leonard, H. Spliid, E. Storr-Hansen, D.E. Wells and C. McKenzie, 1997. Concentration dependent changes of PCB patterns in five species of fish-eating mammals in relation to uptake from food and biotransformation capacity.Archives of Environmental Contamination and Toxicology, 33: 298-311

J.P. Boon, J. Van Der Meer, C.R. Allchin*, R.J. Law*, J. Klungsoyr, P.E.G. Leonard, H. Spliid, E. Storr-Hansen, D.E. Wells and C. McKenzie

Archives of Environmental Contamination and Toxicology, 33: 298-311