A new study of wells in Bangladesh and West Bengal, India, suggests the arsenic test kits used by field workers are frequently inaccurate, producing scores of incorrectly labeled wells. The findings were published this month on the Web site of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society. The print version of the paper is scheduled for the Dec. 15 edition of the journal.
Researchers analyzed 2,866 water samples from wells that were previously labeled by field workers. They found that a large percentage of the wells were labeled erroneously.
Shallow wells, known as tubewells, are commonly used in Bangladesh and India to avoid the region's surface water, much of which contains bacteria that can cause waterborne diseases like cholera. 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.
Arsenic is a slow poison; studies have linked long-term exposure to several types of cancer, according to the U.S. Environmental Protection Agency. The World Health Organization advocates a maximum arsenic level in water of 10 micrograms per liter the standard currently used by the EPA but many developing countries still use a standard of 50 micrograms per liter.
By 1993, the Bangladesh Department of Public Health Engineering had reported widespread signs of arsenic poisoning and blamed tubewell water. WHO called it the largest mass poisoning of a population in history. Similar pro
Contact: Beverly Hassell
American Chemical Society