Field Kits FAIL To Provide Accurate Measure of
ARSENIC
in GROUNDWATER
Prominent researchers question the effectiveness of the milliondollar screening efforts in Bangladesh and India.
BRITT E. ERICKSON
©2003 American Chemical Society
illions of people in Bangladesh and West Bengal, India, are still being exposed to high levels of arsenic in their drinking water, despite a million-dollar screening effort to distinguish safe from unsafe wells, according to laboratory data reported by Dipankar Chakraborti, head of the School of Environmental Studies at Jadavpur University in Calcutta, India, and colleagues. The new results, which appeared in the December 15 issue of ES&T (pp 5385–5394), suggest that the field kits used to measure arsenic in the region’s groundwater are unreliable and that many wells have been incorrectly labeled. The arsenic poisoning problem began with a decision made decades ago to switch from bacteria-laden surface water to groundwater. Although infant mortality and diseases like cholera have decreased significantly as a result of this policy, the symptoms of chronic arsenic poisoning have become an all-too-familiar occurrence because of naturally high levels of arsenic in the underlying sediment. To assess the magnitude of arsenic contamination, the World Bank, the United Nations Children’s Emergency Fund (UNICEF), the World Health Organization (WHO), and several other international aid agencies made a joint decision in 1997 to test all hand-
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JANUARY 1, 2003 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 35 A
UNICEF
pumped tube wells using colorimetric field kits. To date, more than a million wells have been tested using the kits. Those with arsenic levels >50 micrograms per liter (µg/L) were painted red to indicate that the water is unsafe for drinking, and those with levels
