Arsenic mitigation for water supply in bangladesh: Appropriate technological and policy perspectives

Drinking of arsenic-contaminated water and the associated health impacts have been reported in developing and developed countries. Bangladesh is faced with the worst arsenic contamination of groundwater in the world, with an estimated 35 to 77 million people at risk of exposure to drinking arsenic-contaminated tubewell water. Lack of appropriate technologies has complicated and inhibited mitigation initiatives. This paper discusses the data obtained during efforts made to develop technologies for safe water supply by the Government of Bangladesh and its national and international partners. It is expected that the information will contribute towards development of appropriate technologies for water supply for millions of people in Bangladesh and other countries. About 95% of Bangladesh's rural population drinks tubewell. water. Both arsenic removal and alternative technologies were widely promoted for water supply in these areas. The government and its national and international development partners developed various arsenic mitigation technologies for water supply, but most of the arsenic removal technologies were promoted without sound testing and showed poor, questionable and/or confusing performance in real situations. Also, use of most of the arsenic removal technologies was discontinued after a few to several months of installation. Concerns about the microbiological contamination of safe feed water during treatment were noted in arsenic removal options, in addition to high costs, efficiency, social and/or other problems. The 2004 National Policy for Arsenic Mitigation and its Implementation Plan stated a need for access to safe drinking water for all through alternative water technologies while arsenic removal technologies are developed and promoted after specified verification. The national policy specified and widely promoted alternative options such as improved dugwells, safe tubewells, pond sand filters, rainwater harvester and piped water systems from arsenic-safe water sources. A few of the promoted alternative options showed poor functional and social performance, in addition to supplying microbiologically contaminated water. Arsenic-safe shallow tubewells, deep tubewells and piped water systems may be regarded as appropriate technologies under the existing conditions when the performance of the arsenic removal and alternative water technologies were compared. There are constraints in promoting those three water technologies in various hydrogeological conditions throughout the county. A wide range of appropriate technologies needs to be developed and promoted, and the issue of how to deal with the existing millions of arsenic-contaminated tubewells also needs to be considered. Research and development of sound science-based appropriate technologies are urgently recommended for effective realization of the Millennium Development Goal for safe water.