Organochlorine pesticide residues and PCBs in Danish otters (Lutra lutra).

Tissues (71 liver, 2 muscle) of 73 otters found dead in Denmark between 1980 and 1990 were analyzed for organochlorine pesticide residues and PCBs. Geometric means of contaminant concentrations were generally low, but some otters had PCB concentrations considered to be of concern; a greater proportion of these came from isolated populations away from the main population centre in Limfjord. Animals dying of unknown causes had greater concentrations of PCBs than those dying by drowning or in traffic accidents. Adults had significantly higher concentrations of PCBs. Contaminant concentrations were strongly intercorrelated. Concentrations of DDE and PCBs declined significantly during the study period. A sample of otter spraints (faeces) collected in 1990 had low mean concentrations of contaminants. It is concluded that current concentrations of organochlorine pesticide residues and PCBs are unlikely to pose a threat to otter populations.