Background: Over 60,000,000 Bangladeshis are drinking water with unsafe concentrations of 1 or more elements.
Objectives: To evaluate and improve the drinking water testing and treatment plans for western Bangladesh.
Methods: Groundwater from 4 neighborhoods in western Bangladesh was sampled to determine the distributions of arsenic (As), boron (B), barium (Ba), chromium (Cr), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), pH, antimony (Sb), selenium (Se), uranium (U), and zinc (Zn).
Results: The percentage of tubewells that had concentrations above World Health Organization (WHO) health-based drinking water guidelines were Mn 78%, U 48%, As 33%, Pb 1%, Ni 1%, and Cr 1%. Individual tubewells often had unsafe concentrations of Mn and As, or unsafe concentrations of Mn and U. They seldom had unsafe concentrations of both As and U.
Conclusions: These results suggest that the ongoing program of identifying safe drinking water supplies by testing every tubewell for only As will not ensure safe concentrations of Mn, U, Pb, Ni, Cr, and possibly other elements. To maximize efficiency, drinking water testing in Bangladesh should be completed in 3 steps: 1) all tubewells must be sampled and tested for As; 2) if a sample meets the WHO guideline for As, then it should be retested for Mn and U; 3) if a sample meets the WHO guidelines for As, Mn and U, then it should be retested for B, Ba, Cr, Mo, Ni, and Pb. All safe tubewells should be considered for use as public drinking water supplies.