Trace Metals in Soils of the Coeur d'Alene River Valley and Their Potential Effects on Water Quality

Soils in the Coeur d'Alene River Valley(s) have become contaminated with trace metals. Studies presented here show that the degree of contamination in these soils is dependent on distance from the local mining industry's smelting complex in the South Fork Coeur d'Alene River Valley and on river deposited mine wastes in the Main Stem Coeur d'Alene River Valley. Controlled greenhouse studies of garden vegetables and crops grown in trace metal contaminated soils from this locale suggest that most species suffer adverse growth effects and that all species accumulate the trace metals. A rapid decrease of trace metal concentrations in soils with increasing depth in the South Fork Coeur d'Alene River Valley indicates that these soils have become contaminated primarily as a result of atmospheric fallout/washout of smelter emissions. Under laboratory conditions the solubilization of these contaminants generally appears to have a linear relationship with time and rapidly reach equilibrium concentrations which are dependent on the pH of the soil solution and relative soil characteristics. Due to the high solubilities of the oxidation weathering products of the trace metal emissions and the river deposited mine wastes potentially high concentrations of trace metals can be rapidly leached from the contaminated soils by rainfall and high stage water tables