Why were fish from Lake Roosevelt tested for mercury?
All waterbodies contain some mercury, but not all sport fish are tested for mercury. People were concerned about fish from Lake Roosevelt because it’s a popular fishing area and because • a smelter in British Columbia discharged waste and slag into the Columbia River for many years, and the Spokane and Pend Oreille Rivers bring in waste from wastewater treatment plants and mining activities (mostly historical); • earlier studies found that sediment and some fish in Lake Roosevelt were contaminated with toxic metals, including mercury.
