CADMIUM IN MANITOBA'S WILDLIFE

Abstract

We analyzed livers and kidneys of 228 moose, 105 white-tailed deer, 161 elk, 12 caribou, 94 black bear, 31 wolves, and 75 coyotes from Manitoba for cadmium (Cd) levels. Bears has the highest mean concentration (18.89 ± 11.48 μg/dry weight in kidney) followed by white-tailed deer, moose, caribou, elk, wolves, and coyotes (0.31 ± 0.23 μg/dry weight in kidney). Cd levels in renal and hepatic tissues were highly correlated for all species. Concentrations were significantly higher in kidneys than in livers. Except for caribou liver, the concentrations of Cd in livers were positively associated with age of the animals. For black bears, we recorded significantly higher mean concentrations of Cd in females than in males. We found no association between the geographic origin of tissue samples and soil acidity, exposed bedrock, or proximity to anthropogenic sources of Cd. Highly mobile animals, however, likely occupy home ranges that include a variety of habitats, which confounds attempts to identify sources of contamination. Concentration ratios of Cd among trophic levels indicate modest bioaccumulation of the metal for ungulates, high bioaccumulation for black bears, and none for wolves and coyotes. Though the levels of Cd were documented are not life threatening, some animals had concentrations that may be hazardous to humans who consume wild meat. The consumption of liver and kidneys from moose, elk, and deer in Manitoba south of 53° N latitude may lead to a daily intake of Cd exceeding recommended levels. Concern in warranted for the health of First Nation Peoples, particularly those with diabetes who regularly consume organs and meat from wild ungulates.