Heavy metal pollution in the sediments of the Coeur d'Alene river delta
Analysis of sediment samples collected from the Coeur d'Alene River in northern Idaho, USA, indicates that the main stem and the south fork of the river are contaminated with heavy metals (Cd, Pb, Mn, and Zn) from the local mining operations. Laboratory experiments indicate that these metals in the sediments can be leached and reach saturation concentrations in water in a relatively short period of time. The rate of leaching of heavy metals with distilled water appeared to follow first-order kinetics. The saturation concentrations of Mn and Zn in water reached ppm levels from the leaching process. Cadmium and Pb are much less soluble relative to Zn in the sediments. The high concentrations of heavy metals in the sediments are a source of contamination that should be considered for the water quality management planning of the Coeur d'Alene River-Lake system.