The people of Bangladesh used to rely on surface water for drinking, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from water-borne pathogens; however, new evidence suggests disease and death from arsenic and other toxic elements in groundwater are impacting large areas of Bangladesh.
This study produced the first national-scale maps of arsenic, chloride, phosphate, nitrate, sulfide, sulfate, total iron, ferrous iron, and dissolved oxygen in Bangladesh’s groundwater. The map of arsenic concentration suggests over 50,000,000 Bangladeshis are drinking water with unsafe levels of this carcinogen. This map also suggests arsenic-affected groundwater may extend beyond Bangladesh’s borders into India’s 4 adjacent and densely populated states. The major sources of arsenic in Bangladesh’s groundwater might be the dissolution of non-pyrite minerals in a reducing environment, and the anion exchange of sorbed arsenate or sorbed arsenite. The first evidence that Bangladeshis are exposed to arsenic from eating rice (their main staple) and possibly other foods is provided. Evidence that millions of Bangladeshis are drinking water with unsafe levels of other toxic metals besides arsenic is discussed. Several water supply options are evaluated.