Contamination of European otters (Lutra lutra) by PCB congeners and organochlorinated pesticides in the wetlands of western France

During the forty years, otter (Lutra lutra) populations have severely declined over much of Europe. One of the main regression factors appears to be pollution by organochlorine xenobiotics, especially PCBs. The present study took place in France, in the wetlands of the Atlantic border, where otter populations are considered to the stable. Muscle, pericaudal fat, and liver of 33 otters were analysed for 22 PCB congeners and organochlorine pesticides. The mean concentrations of organochlorinated pesticides in samples are relatively low (from 0 to 5.71 mg/kg lipid weight). The PCB concentrations are higher (mean in muscular tissue: 26.19 mg/kg lipid weight), but still remain low compared to similar samples from other countries. The relation between PCB concentration and physiological variables is discussed. Congener specific analysis shows an important contamination due to highly chlorinated congeners and a poor contaminatin due to low chlorinated congeners. Potential hazards due to organochlorinated compounds are also discussed.