The findings will appear in the Jan. 15 print edition of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society. The article was initially published Nov. 20 on the journal's Web site.
Shallow wells, known as tubewells, are commonly used in Bangladesh to avoid the region's surface water, much of which contains bacteria that can cause waterborne diseases. Beginning in the 1970s, international aid organizations dug millions of tubewells, and the program was basically successful in providing bacteria-free water. But officials soon found that the tubewells were reaching groundwater containing high levels of arsenic.
The World Health Organization has called the tubewell crisis in Bangladesh the largest mass poisoning of a population in history. WHO predicts that as many as 270,000 may die from drinking arsenic-contaminated water in the Ganges Delta region.
"There has been a considerable research effort on the effects of drinking arsenic contaminated water in Bangladesh," says Andrew Meharg, Ph.D., a biogeochemist at the University of Aberdeen in Scotland and lead author on the paper. "However, the tubewell water is not just used for drinking water, it is also used for irrigation."
Farmers in Bangladesh use tubewell water for irrigation so that rice can be grown during all six months of the dry season. If the arsenic that is building up in the soil from irrigation moves into rice crops, Meharg says, the exposure of people to arsenic in Bangladesh will be much greater than previously thought.