Those earlier data suggest that species feeding at the higher trophic levels, particularly fish-eating birds, were more likely to be exposed to contaminants through their food. In the past, CWS has not systematically surveyed levels of contaminants in migratory game birds in a program analogous to the various provincial programs which provide consumption guidelines for sport fish. In 1988, however, a national survey of contaminants in waterfowl and other game birds was developed and initiated to address the question of whether or not birds harvested in Canada were safe to eat. To provide a comprehensive data base on contaminants in waterfowl to Health Canada so that the risk to human health of eating those waterfowl may be assessed, and so that consumption guidelines may be issued, if necessary. To provide information to consumers on the levels of toxic chemical residues in waterfowl, and to make recommendations for further work to complement the information presently available.
Species chosen represent the waterfowl most frequently shot by hunters.
Collection of 10 birds per species per location, representative of the hunted population, was requested in most locations. Birds were collected during the regular fall hunting season except in areas of native hunting. Since human health implications of consuming waterfowl were of primary concern, breast muscle, as representative of the edible portion of waterfowl, was targeted for chemical analysis. During sample preparation, all birds were examined for lead shot embedded in the tissue and any fragments found were removed. All chemical analyses were done through contract laboratories which satisfy the quality assurance standards set by the Laboratory Services Section at the National Wildlife Research Centre.