Researchers investigating an unfolding, massive epidemic of arsenic poisoning in Bangladesh say they have evidence that local irrigation practices may be contributing to the problem.
Charles F. Harvey of the Massachusetts Institute of Technology and his colleagues now posit that pumping water for irrigation alters the flow of subterranean water in ways that draw naturally occurring arsenic into aquifers.
But other researchers investigating the region's geology argue that the new finding supports only a limited culpability for irrigation. They point their fingers instead at buried peat deposits, which they say foster chemical reactions that introduce the arsenic into aquifers. Officials need to know the process behind the poisoning to minimize the health impacts.