Toward Sustainable Arsenic Mitigation in Bangladesh and Nepal: Differences in Conditions and Progress of the Measures

This study analyzed the progress and context of arsenic mitigation in Bangladesh and Nepal, which are geographically close and implemented arsenic mitigation measures in similar ways. Arsenic-contaminated groundwater was detected in Bangladesh and Nepal in 1993 and 1999, respectively. Blanket tube well screening revealed that 29% and 1.7% of the tested wells were arsenic-contaminated in Bangladesh and Nepal, respectively. In Bangladesh, 97% of the rural areas had appropriate levels of alternative safe water sources, whereas in Nepal, only 13.8% of arsenic-affected villagers possessed long-term alternative safe water sources in 2018. There are several possible explanations for the discrepancy. First, Bangladesh formulated an arsenic mitigation policy and implementation plan in 2004, whereas Nepal had no such policy, even as of 2020. Second, the government of Bangladesh installed long-term safe water facilities at an early stage of arsenic mitigation. In contrast, the government of Nepal distributed numerous arsenic removal filters for emergency purposes, most of which were unoperated as of 2015. Third, the two countries differ in hydrogeological conditions (the most popular alternative for long-term safe water in both countries), which influences the methods and cost of deep tube well drilling. Specifically, the arsenic-contaminated area of Nepal has a gravel layer between arsenic-contaminated and safe aquifers. This feature meant that deep tube well drilling in Nepal required expensive track-mounted drilling machine for deep tube well installation, which requires 20 times of the cost for hand-pumped deep tube well drilling via inexpensive manual rotary drilling in Bangladesh. The study recommended to formulate a long-term, specific arsenic mitigation plan for Nepal that includes cost estimates for the future activities. On the technical side, inexpensive deep tube well drilling methods that take into account Nepal’s hydrogeological characteristics should be developed.