Modelling bioaccumulation and elimination dynamics of some xenobiotic pollutants (Cd, Hg, PCB, HCB) based on in situ observations with Mytilus edulis

Concentrations and body burdens of bio-availabe Hg, Cd, HCB and PCB isomers were measured by analysing samples of mussels, Mytilus edulis, L in the Eastern Scheldt (location: Kats) and the more heavily polluted Western Scheldt Estuary (location Perkpolder). Despite practical difficulties data could be gathered on the rates of bioaccumulation and elimination of Cd and PCB-101, -138 and -153 under field circumstances by simultaneous transplantations of mussel sample series between these two areas. Mathematical model exercises showed Cd-accumulation and elimination of exchangeable Cd to be slow processes (equilibrium reached in 150 days). In this case Mytilus edulis presumably funtioned as a two-compartment system firmly retaining a less readily exhangeable part of the accumulated cadmium in internal structures. PCB-Isomer accumulation and elimination processes showed a somewhat more dynamic character (equilibrium reached in 45 days) with similar rate constants and complete elimination to base-line levels, suggesting the existence of reversible uptake and loss processes in simple one-compartment system.