Volatilization of arsenic compounds by microorganisms

Methanobacterium thermoautotrophicum is resistant to arsenate; concentrations of up to 350 {micro}M had no effect on growth or methanogenesis. Continuous cultures fed with arsenate transformed arsenic (As), depending on the phosphate concentration, to volatile arsenic species with a yield of 25%. Similarly, various phototrophic purple bacteria are resistant to arsenate and other metalloidal oxyanions at concentrations up to 30 mM; they are able to reduce arsenate. When soil contaminated with arsenic was leached in percolation columns under various environmental conditions, indigenous microorganisms solubilized and slightly volatilized the arsenic present.