In most of the countries affected, governments have been aware of the geogenic contamination issue for several decades, but mitigation efforts have been very limited to date. This is partly because, given other health challenges, drinking water contaminated with arsenic or fluoride is generally not the top priority. In addition, the provision of safe water is a complex matter, requiring appropriate expertise.
Geochemists, social scientists and engineers at Eawag have therefore investigated how levels of arsenic and fluoride in drinking water can best be reduced. Mitigation strategies and tools developed in cooperation with local partners were tested in two case studies in Bangladesh and Ethiopia (Fig. 1). The researchers’ experience has now been summarized in a handbook, which is designed to offer practical guidance for authorities, NGOs, planning agencies and engineers. The “Geogenic Contamination Handbook” shows which areas are most at risk, explains methods of field and laboratory measurement, describes technical mitigation options and discusses how measures can be successfully implemented in accordance with local needs.
Defining the framework
The researchers recommend that, before any measures are planned, the mitigation framework should first be defined. This involves identifying priority areas or wells; determining whether drinking water (as opposed to food or food preparation) is indeed the main source of geogenic contaminants for the population concerned; and, at the local level, assessing not only the technical options and financial resources available but also institutional support and community acceptance (Fig. 4). In many cases, projects prove to be unsustainable over the long term because funding is not assured or local requirements are not taken into account in the planning process.