1 Red wells or green wells and does it matter? Examining household use of arsenic contaminated water in Bangladesh A.K.E. Haque, Z.H. Khan, M. Nepal, and P. Shyamsundar 1 October 18 2011 1. Introduction Bangladesh currently faces a major health calamity because of arsenic contamination of groundwater aquifers. Bangladesh has copious quantities of ground water, but the alluvial aquifers of the Ganges delta are polluted by naturally occurring arsenic (Nickson et al. 1998). Approximately 27 percent of shallow tube wells in Bangladesh are estimated to have arsenic content that exceeds the government’s safety standards of 50 g/liter (Caldwell et al. 2006; BGS and DPHE 2001). 2 Some 46 percent of wells exceed the safety standards set by the World Health Organization of 10 g/liter (BGS and DPHE 2001). 3 For Bangladesh, this means that an estimated 27 to 60 percent of its population is at risk from arsenic exposure (Smith, Lingas and Rahman, 2000). Historically, Bangladesh has been very successful in providing its population with access to safe drinking water. Death due to cholera and diarrheal disease was effectively contained in the seventies and eighties by replacing existing sources of drinking water with tube wells, a strategy 1 United International University (akehaque@gmail.com), Transparency International, Bangladesh (zhkhan@ti-bangladesh.org) and SANDEE (manin@sandeeonline.org and priyas@sandeeonline.org). 2 Based on a national sample of 3,534 tubewells. 3 Air and water quality international standards set by the World Health Organization can differ from national standards. The World Health Organization’s arsenic standards apply in several developed countries but many developing countries have set their own standards for practical reasons.