Microbially-Mediated Reductive Dissolution of Arsenic-Bearing Minerals in a Gold Mine Tailings Impoundment

摘要

The mechanisms of release of arsenic in gold mine tailings were investigated. The highest concentration of dissolved As (75 mg/L) was observed near the base of the tailings impoundent, in close association with a peat layer. Elevated concentrations of reduced iron and hydrogen sulfide were also measured at the base of the impoundment. High numbers of iron-reducing and sulfate-reducing bacteris were detected at depths within the impoundment which correlated with dissolved As. Fe and H_2S. The data presented in this paper suggest that arsenic is released from the tailings by bacterially-mediated reductive dissolution of As-bearing iron minerals.