High levels of arsenic in large parts of the Ganges Delta have poisoned
millions of people during the last 2 decades and the risk of contamination
of drinking and irrigation water with arsenic continues to pose a threat to
the lives of millions worldwide (Bull World Health Organ. 2000; 78:1093-1103). But the mechanisms underlying the release of
arsenic from sediments into ground waters are poorly understood.
Now, scientists from England and India report evidence from laboratory
studies that anaerobic iron-reducing bacteria (from a contaminated aquifer
in India) thrive under conditions that favor the release of a toxic form of
arsenic (Nature. 2004;430:68-71). Because the bacteria
require organic carbon to grow, the researchers suggest that their findings
support theories that the introduction of organic carbon through agricultural
practices (such as irrigation) is a factor in mobilizing arsenic from sediment
into the water supply. If true, the information could help scientists devise
strategies to manage arsenic-rich ground waters.
Stephenson J. Arsenic-Tainted Water. JAMA. 2004;292(7):794. doi:10.1001/jama.292.7.794-d