A steady-state model of PCB bioaccumulation in the sea bass (Dicentrarchus labrax) food web from the Seine estuary, France

Polychlorinated biphenyls (PCBs) were measured in six compartments of die sea bass (Dicentrarchus labrax) food web from the Seine estuary. Similar PCB patterns were observed in all samples. The main components possess the - 245, 234, - 2345 chlorine substitution. Contamination increases with the trophic level. The highest concentrations were found in sea bass amounting 300 ng g(1) (d.w.) in the oldest individuals. A six-compartment steady-state food web model is proposed for the food web leading to the sea bass. Several exposure pathways are considered in the description of the accumulation by animals: the ingestion of particulate contaminants associated with either phytoplankton and detritus, and the respiratory uptake of truly dissolved contaminants in the overlaying water. The application of this model indicates that feeding is the principal route of contamination, especially for PCBs which have more than four chlorine atoms and that feeding preference, phytoplankton lipid fraction, and organic carbon content of detritus are parameters which mostly determine the bioaccumulation in this food web.