Arsenic study provides opportunity to mitigate the water crisis in Bangladesh
10 September 2002
Wells in Bangladesh delivering water with high levels of arsenic in it are in many cases used unnecessarily. American and Bangladeshi researchers report in this month's Bulletin of the World Health Organization (www.who.int/bulletin) that in their study area other tube wells nearby were safe and could be used instead. This offers a short-term option which, if taken up systematically throughout the country, could save millions from the cancers and cardiovascular diseases caused by chronic exposure to arsenic. At present 30–36 million people in Bangladesh are thus exposed.
"Well-switching should be more systematically encouraged in Araihazar and many other parts of Bangladesh and West Bengal, India," conclude Alexander van Geen and his colleagues, who come from Columbia University in New York, and Dhaka University and the National Institute for Social and Preventive Medicine in Bangladesh.
The authors found that 48% of the 4997 contiguous tube wells in the Araihazar district (population 55 000) met the current Bangladesh standard for drinking-water, which is a maximum of 50 micrograms of arsenic per litre. Calculating the distance from each unsafe well to the nearest safe one, they found that although only half the inhabitants had access to safe water from their own well, 88% lived within 100 metres of a safe one, and 95% within 200 metres. Six currently safe wells that were sampled every two weeks for a year gave no indication of significant seasonal fluctuations in arsenic concentrations. This is consistent with the data available for other parts of Bangladesh.
The small fraction of the millions of tube wells in Bangladesh that have been tested are painted red or green according to results of arsenic tests, but switching to a safe well has not been aggressively promoted. In Araihazar 43% of the inhabitants surveyed thought this would be the best immediate option; 31% were for deepening the unsafe well or treating the water in it; and 20% were for going back to surface water without treatment (although the microbial diseases transmitted by contaminated surface water were the reason for drilling the tube wells in the first place).
Switching from your own unsafe well to someone else's safe one is not so simple, however. Most wells are privately owned. Women are traditionally not expected to leave their bari or cluster of related households unaccompanied. The need for privacy can be an obstacle, as many of the wells are located close to the family latrine. On the other hand, crowding around safe wells does not appear to be a major issue, as user density already varies considerably, some wells having less than 20 users, others more than 120.
"Bangladesh is facing a major drinking-water crisis, but this study shows how it could be significantly reduced by relatively simple changes in behaviour and social norms," commented Jamie Bartram of WHO's water safety programme.
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