Metals, metalloids and metallothionein in tissues of fish from a Canadian freshwater system receiving gold mining effluents

White suckers (Catostomus commersoni) and walleye (Stizostedion vitreum) were captured from Balmer Lake, a shallow freshwater system in Central Canada that has served as the final repository for tailings from two gold mines for more than 40 years and from nearby reference locations. Concentrations of As, Se, Hg, Cd, Cu, Ni, Pb and Zn were measured in liver, kidney and gill tissues. Enrichments of several metals were identified in the fish captured from Balmer Lake relative to the reference sites. Concentrations of the metal binding protein, metallothionein, were also measured in liver tissue of fish from Balmer Lake and the reference locations in order to examine relationships between metallothionein concentrations and any of the analyzed metals. Data will also be presented for metals and metallothionein in viscera of small bodied forage fish. These data have been collected from several experiments in which forage fish were caged for brief periods at reference sites, within Balmer Lake, and at several sites downstream from the release of Balmer Lake waters. The results of these studies show the potential for accumulation of several metals/metalloids in fish exposed to effluent from gold mining. They also demonstrate the potential for metallothionein to be used as an indicator of long and short term exposure to metals