Contamination des crustacés décapodes par les composes organohalogénés : étude détaille de la bioaccumulation des PCB chez l'araignée de mer Maja brachydactyla

Marine decapod crustaceans are macrobenthic opportunist species, of great commercial interest, and can accumulate pollutants. Worrying about consumers' safety, polychlorobiphenyls (PCBs), polybromodiphenyl Ethers (PBDEs) and dioxins (PCDD/Fs) were analyzed in four crustacean species from the coastal waters of Brittany and Normandy. As regards to regulations, the consumption of crustacean muscle doesn't raise any health problems. The second objective of this study was to evaluate the biological processes influencing PCB bioaccumulation in the spider crab Maja brachydactyla. From a quantitative point of view, organotropism, diet and age were the major factors acting on contamination. From a qualitative point of view, PCB fingerprints depended on sex, and to a lesser extent, on the species migratory behaviour. The stable isotopic analysis of carbon (gamma13C) and nitrogen (gamma15N) in spider crab food web confirmed the high level of complexity of food relations in the case of omnivorous top predators. The use of both stable isotopic method and contaminant analysis highlighted the bioamplification of the most persistent PCB congeners along the spider crab food web. Conversely, some compounds with particular chemical structure are metabolized by decapod crustaceans.