Effect of a smelter complex on the regional distribution of cadmium, lead and zinc in litters and soil horizons.

The distribution of cadmium, lead and zinc concentrations in litter and mineral soil horizons from the Kootenay region were studied to determine the effect of the 70-yr operation of the world's largest base-metals smelter complex at Trail, British Columbia. Metals were retained near the surface in litter and surface mineral horizons and concentrations in deepest horizons were lower and normal for uncontaminated soils. Metal concentrations in surface horizons were significantly related to distance from the smelter and site elevation in the mountainous region. Regression equation models to predict metal concentrations as functions of distance and/or elevation accounted for 69.8, 93.3 and 76.7% of variance in litter concentrations of Cd, Pb, and Zn, respectively, and 91.3, 50.6, and 64.0% of their variances in surface mineral horizons. In view of concomitant random distribution of metal concentrations in deepest horizons, these relationships and low Zn/Cd ratios in surface horizons nearest to the smelter indicated surface deposition of airborne smelter emissions was responsible for metal contamination of Trail area surface soils.