INTEGRATED APPROACH FOR EFFECTIVE AND SUSTAINABLE ARSENIC MITIGATION PROGRAMS WITH A DIGITAL DECISION-MAKING TOOL: EXPERIENCES FROM THREE CONTRASTING GEOLOGICAL AREAS OF BANGLADESH

Ensuring safely managed drinking water for all in Bangladesh is a major concern to achieve SDG 6 in the context of water quality. Tubewells are one of the easy and sustainable options for rural drinking water supply, but detection of arsenic (As) in wide areas of Bangladesh, the Government has been facing the challenges to provide safe drinking water. In Bangladesh several approaches have been adopted for As mitigation, however absence of integrated and harmonized approaches, regular water quality monitoring, capacity enhancement of critical mass technocrats (incl. local drillers), technological sustainability, digital decision making tool and inadequate knowledge of local geology slowed down this mitigation process. Recently UNICEF and Department of Public Health Engineering of Bangladesh (DPHE) introduced a practical concept named the Arsenic Safe Union (ASU) considering socio-economic issues along with evidence based decision making with Local Government Institutions (LGIs) through vulnerability risk assessment to select the highly affected unions, As screening and water source mapping with context based appropriate technology selection. Mainly deep tubewell (>150 m) is targeted to provide As safe water in the context of Bangladesh standard (<50 µg/L) using the ASU approach. The Sustainable Arsenic Mitigation (SASMIT) concept was developed for targeting safe aquifers through identification of sediment color, and its scientific validation, to help the local well drillers who work independently to provide As safe drinking water to the local population. A harmonized approach using the ASU and the SASMIT approach has been developed and implemented in three different areas of Bangladesh to validate its suitability for As mitigation process which includes drillers mapping for local shallow aquifers distribution and water quality with sediments color before detail investigation, As screening for hot spot identification and priority based zoning for As contamination can be done. With the help of the SASMIT approach, safe shallow-oxidized and intermediate deep aquifers can be identified based on drillers mapping, geophysical and hydrogeological investigations for making implementation plans. These layers of analyses can be integrated in digital platform (ASMITAS) to come out with site selection process for proper distribution of implementation well.