The concentrations of arsenic and other toxic elements in Bangladesh's drinking water.

Abstract

For drinking water, the people of Bangladesh used to rely on surface water, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from waterborne pathogens; however, new evidence suggests disease and death from arsenic (As) and other toxic elements in groundwater are affecting large areas of Bangladesh. In this evaluation, the areal and vertical distribution of As and 29 other inorganic chemicals in groundwater were determined throughout Bangladesh. This study of 30 analytes per sample and 112 samples suggests that the most significant health risk from drinking Bangladesh's tubewell water is chronic As poisoning. The As concentration ranged from < 0.0007 to 0.64 mg/L, with 48% of samples above the 0.01 mg/L World Health Organization drinking water guideline. Furthermore, this study reveals unsafe levels of manganese (Mn), lead (Pb), nickel (Ni), and chromium (Cr). Our survey also suggests that groundwater with unsafe levels of As, Mn, Pb, Ni, and Cr may extend beyond Bangladesh's border into the four adjacent and densely populated states in India. In addition to the health risks from individual toxins, possible multimetal synergistic and inhibitory effects are discussed. Antimony was detected in 98% of the samples from this study and magnifies the toxic effects of As. In contrast, Se and Zn were below our detection limits in large parts of Bangladesh and prevent the toxic effects of As.