Distribution and Mobilization of Arsenic and Antimony Species in the Coeur D'Alene River System

摘要

The mining industry along the South Fork of the Coeur d'Alene River in northern Idaho is a major producer of silver, lead, and zinc in the United States. Mining operations in the past have discharged huge amounts of mining wastes into the South Fork of the river causing a serious pollution problem for the Coeur d'Alene River system. Sediments in the South Fork and the main stem of the river are contaminated with arsenic(As), antimony(Sb), cadmium(Cd), lead(Pb), zinc(Zn), and other metals. Leaching of As and Sb from the sediments along the main stem depends on the pH of the water and on the iron and manganese content of the sediments. The releases of As and Sb from the sediments appear to associate with the free iron oxides and manganese oxides in the sediments. However, releases of sediment Sb were generally found linear with respect to time while asymptotic limits on As releases were reached. Significant amounts of Zn, Fe, and Mn were also released during leaching, but Cu, Cd, Pb, and Ni were much less leachable. According to the study interaction of water with the existing sediments is likely to be a major factor controlling the water quality of the Coeur d'Alene River.