Bioaccumulation of pollutants and measures of biomarkers in the Zebra mussel (Dreissena polymorpha) from downstream river Seine

Measurements of contamination by three heavy metals (Cd, Cu and Zn), 20 pol y-chlorobiphenyls (PCB) and 14 polycyclic aromatic hydrocarbons (PAH) were performed in Zebra mussels (Dreissena polymorpha) taken from the river Sein e, in six populations located upstream and downstream from the city of Roue n (France). The results indicate that this bivalve species agressively accu mulates these contaminants and thus can be used as a sentinel organism for the monitoring of water quality in the Seine river. Two stations were of pa rticular interest for the contamination pattern of mussels. Animals taken i n the station La Bouille, located just downstream from Rouen harbour, exhib ited the highest levels in PAH and the second highest in PCB and Cd, thus i ndicating that contaminants originating from the city and industrial zone o f Rouen contribute to the contamination levels of biota in the Seine river. Mussels from the station Vieux-Port were characterised by PCB and PAH burd ens noticeably different from those measured in animals originating from th e other sites, especially as they had the highest levels in toxic PCB conge ners in term of dioxin-equivalent toxicity. Measurement by immunological methods of the expression of multixenobiotic r esistance proteins (MXR) in the gills of Zebra mussels indicate that the an imals from the station La Bouille had the highest concentrations of those p roteins. Globally, animals living at and downstream from La Bouille exhibit higher levels of MXR proteins, suggesting therefore that they are more exp osed to various toxing than those animals living upstream.