SOURCE AND FATE OF METALS IN TWO CATCHMENTS OF THE UPPER COLUMBIA RIVER BASIN, STEVENS COUNTY, WA

In 2001, the United States Environmental Protection Agency identified the Teck Cominco zinc smelter in Trail, BC as a source of heavy metal contamination to the Lake Roosevelt/Columbia River system. Records indicate the Trail smelter acted as a direct input of smelter slag to the upper Columbia River system contributing an estimated 11.6 billion gallons of smelter waste before dumping ceased in 1994. However, several mine sites in both Canada and the U.S., in operation through the beginning of the 20th century, must also be considered when evaluating the source and fate of heavy metal contaminants in the upper Columbia River catchment. Two of these sites, the Gladstone/Electric Point and St. Crispin mines located in Stevens County, Washington, are of particular interest. The Gladstone/Electric Point mine exhibited higher production than any other mine in the area producing 46,295,104 pounds of lead and 55,371 pounds of zinc from hydrothermal sulfide deposits during the first half of the 20th century. The St. Crispin mine has no existing record of production but chances of contamination are high due to the location of the mine shafts directly in Sheep Creek, a tributary to the upper Columbia River. In an effort to better constrain the natural and anthropogenic sources of heavy metals in the Columbia River system, we determined concentrations for lead, copper, arsenic, and zinc in surface water, country rock, mineralized rocks, smelter slag and tree heartwood in the vicinity of the St. Crispin and Gladstone/Electric Point mines, and the Northport, WA smelter. These data inform our understanding of the Lake Roosevelt/Columbia River system by allowing us to make important spatial and temporal interpretations regarding the source, fate and transport of environmental contaminants relevant to the resolution of international environmental issues.