A comparative study of cadmium and copper in ruffed grouse (Bonasa umbellus) in regions with and without historic mining.

Mining activities can increase the bioavailability of metals in aquatic and terrestrial ecosystems. Following over 100 years of copper mining in portions of Michigan's Upper Peninsula (UP) terrestrial ecosystems retain vast quantities of waste rock with traces of cadmium and large concentrations of copper. We compared liver cadmium and copper concentrations in ruffed grouse (Bonasa umbellus), a popular game bird from landscapes with and without historic mining. We also used chickens (Gallus domesticus) to determine whether mine waste was a direct source of liver cadmium. Cadmium and copper levels did not differ between mining areas in Michigan and non-mining areas in Wisconsin. We found nearly significant difference between sexes in cadmium levels. Cadmium levels for all chickens were below the method detection limit of the lab (0.03 mg/kg) and copper levels did not differ in the experimental chickens. These results suggest that the historic mining in the western UP is not leading to higher cadmium or copper uptake in grouse.