Promotion of well-switching to mitigate the current arsenic crisis in Bangladesh.

OBJECTIVE: To survey tube wells and households in Araihazar upazila, Bangladesh, to set the stage for a long-term epidemiological study of the consequences of chronic arsenic exposure. METHODS: Water samples and household data were collected over a period of 4 months in 2000 from 4997 contiguous tube wells serving a population of 55000, the position of each well being determined to within +/- 30 m using Global Positioning System receivers. Arsenic concentrations were determined by graphite-furnace atomic-absorption spectrometry. In addition, groundwater samples collected every 2 weeks for an entire year from six tube wells were analysed for arsenic by high-resolution inductively coupled plasma-mass spectrometry. FINDINGS: Half of the wells surveyed in Araihazar had been installed in the previous 5 years;…