Bioaccumulative Behaviour of Some PCB Congeners in Lake Geneva Brown Trout (Salmo trutta lacustris L)

Abstract

The bioaccumulation of PCBs has been studied for 60 Brown trout in Lake Geneva (Switzerland). The contamination level (1–3 ppm in wet weight, 10–30 ppm in lipid weight) is rather high.

Bioaccumulation curves (concentration as a function of the weight of the fish) have been established for 6 congeners and total PCBs. The total concentration of PCBs in wet weight increased with the weight of the fish; highly-chlorinated congeners (I.U.P.A.C. nr. 180, 2,3,4,5,2′,4′,5′-heptachlorobiphenyl) presented a faster, and lightly-chlorinated (I.U.P.A.C. nr. 28, 2,4,4′-trichlorobiphenyl) a slower, bioaccumulation tendency.

The total concentration of PCBs in lipid weight was constant, the concentration of congener 28 increasing and of congener 180 decreasing with the weight of the fish. This is attributed to the antagonistic effects of “growth and lipid dilution” and of the decrease of elimination kinetics as a function of the weight (and age) of the fish.

The partitioning theory and the pharmacokinetic approach are complementary methods for analysing this field data.