Arsenic is a highly toxic and ubiquitous metalloid dispersed throughout the earth's crust. A devastating health crisis has been unfolded in many parts of the world, due to arsenic enrichment, most likely of natural origin, of groundwater used for drinking and cooking. The mobilization of arsenic from aquifer materials usually occurs under reducing conditions and is microbially mediated. In Bangladesh elevated dissolved As concentrations in groundwater were found mostly in the form of inorganic arsenic as arsenite, detected by several analytical techniques including one that uses a modified...