Health effects from arsenic in groundwater of the Bengal delta: Effects of iron and water storage practices

Abstract

An estimated population of 50 million people is exposed to arsenic concentrations above 10 g/L in drinking water in the Bengal delta plain. Arsenic is carcinogenic, and interpretation of epidemiological studies from Taiwan and other parts of the world shows different risk estimates for getting skin cancer and other internal cancers like lung, liver, kidney, and bladder. The aim of the study was to estimate the risk of getting skin cancer based on the different literature values and to investigate the effect of the presence of iron in the groundwater and people's habit of water storage on the risk estimates. The study showed only one arsenicosis case (estimated 13 cases) and no cancer incidences among the interviewed population (estimated 1–3 cases). Higher incidences of skin lesions were observed in areas with lower iron concentrations compared to higher iron concentrations, suggesting that the co-occurrence of higher iron concentrations has an indirect effect on the exposure of arsenic concentrations. This could be caused by the discarding of water with high iron concentrations or storage of water, which leads to the removal of iron and arsenic and results in lower arsenic exposures through the drinking water. The other main reasons could be that most of the installed tube wells are not more than 10 yr old, and thus, exposure is only recent. The study showed that the actual risk of getting various cancers may be reduced by 35% because of the present water storage habits. The study further discusses the need for revised guideline values especially in developing countries.