Sustainable Arsenic Mitigation Using Sediment Colour Concept in Bangladesh − A Strategy for Global Implication

Millions of people, mainly in developing countries are affected by As through drinking water. The sensitivity to As poisoning is related to the economic situation of the individual and As poisoning case is structured in several ways by class and gender. A wide gap between the number of exposed people and the slow pace of mitigation programmes in rural areas of developing countries is the main problem for increasing the safe drinking water coverage. Therefore the principal challenge is to develop a sustainable mitigation option that the rural and disadvantaged people can adopt and implement by themselves. New approaches have emerged during the recent years in Bangladesh, mainly from people's own initiative. The local drillers target presumed safe aquifers on the basis of colour and texture of the sediments. A correlation between the colour characteristics of the sediments and the groundwater redox conditions and risk for As mobilisation in groundwater has been established. Risk of high concentrations of As is prevalent in the black sediments, whereas the brownish or reddish brown sediments have lower As concenntrations. However for validating the sustainability of this mitigation option detailed geological, hydrogeological and microbiological investigations are needed. The sustainability of the aquifers needs to be assessed by combining results from various field and laboratory investigations and by developing predictive models. There is also a need to raise public awareness as well as to educate the local drillers for safe installation of tubewells based on sediment colour concept. Awareness raising and community mobilisation are two top priorities for implementing a sustainable safe water project in rural areas as a global arsenic mitigation strategy.