Over the past three decades, the occurrence of high concentrations of arsenic (As) in drinking water has been recognized as a severe global public-health concern (Bhattacharya et al. 2002, Mandal and Suzuki 2002, Ng et al. 2003). The global As-contamination scenario has changed considerably in recent years, with the discovery of new As affected sites. The delayed health effects of exposure to As, the lack of common definitions and of local awareness, as well as poor reporting in affected areas are all major problems in determining the extent of the arsenic-in-drinking-water problem (WHO 2008).