ISOTOPIC AND ELEMENTAL COMPOSITIONS OF LICHENS AS TRACERS OF SMELTER EMISSIONS IN WASHINGTON STATE AND BRITISH COLUMBIA
To evaluate the impact of this smelter on the surrounding area and cross-border along the Columbia River and in Colville National Forest lichen samples were collected and analyzed for heavy metal concentrations and Pb isotope composition. Previous work, e.g., , shows that the lead refined at this smelter has a characteristic isotopic composition that can be used to fingerprint Pb emissions from the smelter.
Our study shows that there is high pollution around the smelter that dissipates and returns to normal levels further from the smelter. Heavy metals Pb, Zn, and Cd have concentrations at levels as high as 182, 673 and 5.27 ppm, respectively. These maximum Pb, Zn, and Cd concentrations are 55, 15, and 13 times USFS threshold values, respectively. Specialty metals such as indium (In) and bismuth (Bi) are produced as co-products of Zn and Pb production. Ore concentrates processed at Trail contain small quantities of In and Bi. Our study indicates that significant In and Bi are released during processing and reach natural areas as far as 24 miles downwind of the smelter. Lichen samples exhibit In and Bi concentrations as high as 0.70 and 2.6 ppm, respectively. Lead isotope fingerprinting will be used to identify the relative contribution of the smelter and other sources to the identified pollution. This will complement the metal concentration study providing further evidence for the source of metal pollution along the Columbia River.
 Shiel et al. (2010) Science of the Total Environment, 408.