Metals in Lake Simcoe sediments and tributaries: Do recent trends indicate changing sources?

► Conducted survey of sediment concentrations of 17 metals across Lake Simcoe. ► Metal concentrations highest in Kempenfelt Bay sediments from 1950s to 1970s. ► As, Cd, Cr, Cu, Pb, Sb, Zn in sediments remain elevated over pre-1900 concentrations. ► Tributary metal concentrations highest downstream from urban areas. ► Shift from point source to diffuse metal pollution such as runoff and atmospheric.