Modelling growth and bioaccumulation of Polychlorinated biphenyls in common sole (Solea solea)

Experiments were performed on juvenile sole in controlled conditions in the aim of understanding how the biology of common sole may affect the accumulation and dilution of Polychlorinated biphenyls (PCBs). The fish were raised in optimal conditions and divided into two tanks: one control tank and one PCB tank. 4 PCB congeners were added to food for 3 months in the PCB tank; the soles were subsequently fed unspiked food for 3 months. Growth (length and weight) and PCB concentrations were monitored in both tanks and juvenile sole growth was not significantly affected by PCBs in our experimental conditions. We used the Dynamic Energy Budget (DEB) theory to model sole biology and paid special attention to model calibration through the wide use of data from the literature. The model accurately reproduced fish growth in both tanks. We coupled a bioaccumulation model to reproduce the concentration dynamics of the 4 PCB congeners used. This model did not require additional calibration and was dependent solely on the growth model and PCB concentrations in food. The bioaccumulation model accurately simulated PCB accumulation in fish, but overestimated PCB concentrations in fish during the dilution phase. This may suggest that in addition to PCB dilution due to growth, PCB concentrations decreased due to other PCB elimination mechanisms. Finally, we discussed potential improvements to the model and its future applications.