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An estimated population of 50 million people is exposed to arsenic concentrations above 10 μg/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.
Anitha Kumari Sharma is currently doing her Ph.D. at the Environment & Resources, Technical University of Denmark. Her research is centered on the removal of arsenic using naturally occurring iron and hair arsenic concentrations as an indicator of exposure.Jens Christian Tjell is a professor (docent) in environmental chemistry at the Environment & Resources, Technical University of Denmark. His research has centered on the reuse of sludge and other waste products in agriculture, focusing on risks associated to trace elements following the changes of materials flow introduced by changes in land use. He has many years of international experience in the United Nations and in developing countries. Tjell's focus is on sustainable recirculation of materials in developing countries between urban and rural areas to increase agricultural productivity through resource conservation. A recent activity is on the flow patterns for arsenic and its removal from drinking water.
Hans Mosbæk is an associate professor (docent) at the Environment & Resources, Technical University of Denmark. His principal area of research is in air pollution in particulates and passive sampling and environmental analytical chemistry in all areas of developing countries, especially cooperation with foreign universities in Africa and Southeast Asia.