A five-compartment steady-state food web model is proposed for the benthic food web leading to the dab. Three exposure pathways are considered in the description of accumulation by benthic animals: ingestion of particulate contaminants associated with either sediment or phytoplankton, and respiratory uptake of free dissolved contaminant in overlaying water. Application of the model to a simple food web in the Bay of Seine (Eastern Channel) indicates that : a) feeding is the principal route of contamination, especially for PCB which have more than four chlorine atoms in the molecule ; b) excretion and growth rates, phytoplankton lipid fraction and organic carbon content of sediment are the parameters which mostly determine the chemical bioaccumulation in the food web.