Organochlorines and mercury in waterfowl harvested in Canada.

Samples of breast muscle from 32 species of waterfowl collected from 123 sites across Canada were analyzed for chlorobenzenes (CBz), chlordane-related compounds (CHL), hexachlorocyclohexanes (HCH), DDT, mirex, dieldrin, PCBs and mercury. SigmaDDT, SigmaCBz and SigmaPCB were the compounds most frequently found above trace levels. SigmaHCH and SigmaMirex were detected the least often. Mercury was detected in all of the mergansers, over 50% of dabbling, bay and sea ducks, and in less than 2% of the geese analysed. The highest levels of contaminants were generally found in birds feeding at higher trophic levels such as sea ducks and mergansers. With the exception of a few samples of mergansers and long-tailed ducks from eastern Canada, which contained SigmaPCB concentrations of 1.0-2.4 mg kg(-1), SigmaPCB levels were less than 1 mg kg(-1) wet weight. Only one merganser from eastern Canada had a SigmaDDT concentration (2.6 mg kg(-1) ww) which was greater than 1 mg kg(-1) ww. The highest SigmaCHL (0.10 mg kg(-1) ww) was also found in mergansers from eastern Canada. Levels of total mercury in breast muscle were either low (< 1 mg kg(-1) ww) or below detection limits with the exception of a few samples of mergansers from eastern Canada which contained mercury concentrations of 1.0-1.5 mg kg(-1) ww. Health Canada determined that the organochlorine and mercury levels found in samples of breast muscle of ducks and geese analysed in this study did not pose a health hazard to human consumers and therefore these waterfowl were safe to eat.