A MODEL FOR THE BIOACCUMULATION OF CHLOROBIPHENYL CONGENERS IN MARINEMAMMALS

The behaviour of chlorobiphenyls in marine mammals is best described b y a pharmacokinetic model where the blood acts as the central transpor t compartment between the external environment and a number of periphe ral organs, each maintaining a dynamic balance with the concentrations in the blood. Thus, blood samples can be a useful tool in monitoring programmes of chlorobiphenyl concentrations. Differences in the chloro biphenyl patterns between seals and fish could be explained by the str ucture-biotransformation relationship developed in an experimental stu dy. A harbour porpoise (Phocoena) seemed also able to metabolize chlor obiphenyl congeners with vicinal hydrogen atoms in the meta and para p ositions and two ortho-Cl atoms. Because the ratios between persistent and metabolizable congeners differed between specimens, it was not po ssible to derive 'dioxin type' toxic equivalents from concentrations o f congeners occurring at much higher concentrations by calculation of their ratios.