Arsenic-safe aquifers as a socially acceptable source of safe drinking water — what can rural Latin America learn from Bangladesh experiences?

Geogenic arsenic (As) are found at elevated levels in groundwaters resources in many regions of the world. Since 1998, As problem is ‘discovered’ each year in groundwater in parts of the world, where the problem was not known. This calls for global approaches for sharing and exchange of information and experiences. Two pilot areas, Matlab Upazila, representative of the Bengal delta where 35 million of rural population is at risk, and Río Dulce alluvial cone (NW Argentina), representative of Latin America where >5 million people were at risk, were compared to identify mechanisms of As mobilization and sustainable mitigation options. In both areas, As mobilization is governed by site- or zone-specific hydrogeochemical conditions that result in extremely heterogeneous lateral and vertical distributions of As in the shallow groundwaters. In rural Bangladesh, different As removal techniques, e.g., sand filters, Alcan filters, Bishuddya filters, or rainwater harvesters have been provided by governmental and non-governmental organizations, but their social acceptance is low. In ontrast, ‘Targeting As-safe aquifers’, which calls for installation of safe wells, was identified as a socially accepted option. This was proven currently in our pilot project in Bangladesh, where sediment color could be used to identify As-safe aquifer zones for installation of tube wells. Initial results from our investigation in NW Argentina are complex because the conditions and sources of As to aquifers in Argentina are very different from those in Bangladesh