DISTRIBUTION AND MOBILIZATION OF ARSENIC AND ANTIMONY SPECIES IN THE COEUR-DALENE RIVER, IDAHO

Sediments from the Main Stem and the South Fork of the Coeur d'Alene River are contaminated with As, Sb, and other heavy metals from the local mining operations. Water samples from the South Fork and the Main Stem showed high levels of As (0.11–1.64 μg/L) and Sb (0.23–8.25 μg/L) relative to those from the North Fork (0.26 μg/L As and 0.17 μg/L Sb). Arsenic(III) was found to be the predominant form in the waters of the South Fork and Main Stem of the Coeur d'Alene River, whereas the North Fork generally had higher As(V) concentrations. The major inorganic Sb species was Sb(V) in all three branches of the river. Leaching of As and Sb species from the contaminated Main Stem sediments depends on the pH values of the water as well as on the free iron oxides and manganese oxides present in the sediments. Factors controlling the distribution and mobilization of As and Sb species in this aquatic environment are discussed. © 1990, American Chemical Society. All rights reserved.