In fall 2005, fish contamination by PCBs was observed in the Rhone river in the vicinity of Lyon (France). This incidental observation triggered a series of investigations on fish and sediment all along the main stream, leading to consumption prohibitions along several stretches. In parallel, a project was set up, aiming to develop a model that would describe the transfer of PCBs from sediment to key fish species, in order to help determine sediment management guidelines in the future. Key fishes and invertebrates were caught for PCBs analysis in three sites along the Rhone river: (1) the reference site, upstream Lyon and before the first contaminated area; (2) a site close to Lyon, located in this contaminated area; (3) a site downstream Lyon. The first step of the model's development describes the food webs of these key species, namely the barbel (Barbus barbus), the chub (Squalius cephalus), and two breams (Abramis brama and Blicca bjoerkna), all large and long-living species prone to accumulate PCBs over many years. Food webs description is based on the combined use of stomach contents analysis of fish and δ13C and δ15N isotopes measurements on fish and their potential food resources (invertebrates and aquatic plants communities). The PCB contamination of these fishes and invertebrates is then studied, and the first attempts of the bioaccumulation model, developped to describe the tranfer of PCB along these food webs, are presented.