ABSTRACT
Microorganisms such as At. ferrooxidans, At. thiooxidans, L. ferrooxidans, Sulfate Reducing Bacteria, Bacillus spp. as well as arsenic-tolerant Thiomonas spp. inhabit such sulfide ore deposits, mine waters, and processed mill tailings. Arsenite and arsenate concentrations in the solution, during the growth of At. ferrooxidans, in 9K medium were measured along with ferric-ferrous ion levels and cell population. Arsenic minerals can also be oxidized by neutrophilic organisms. For example, arsenite can be oxidized by Thiomonas sp. and various Bacillus sp. Arsenite could be effectively removed during growth of At. ferrooxidans. The presence of active growing cells may be essential for arsenic removal from solution. Biogeochemical cycles in mining environments have been explained through conceptual models. Primary arsenic mineral dissolution is mediated by acidophilic microorganisms using arsenic, iron, and sulfur as energy substrates and also by arsenic-tolerant organisms. Indigenous microorganisms such as At. ferrooxidans and Thiomonas sp. take part in arsenic mineral dissolution using arsenic, iron and, sulfur as energy substrates.
