Sustainable approaches to minimize arsenic in drinking water and rice in Vietnam

• Applicant: Professor Dr. Andreas Kappler
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 400079674

Arsenic-contaminated groundwater is a major threat to tens of millions of people, in particular in South and South-East Asia, via its use as drinking water and irrigation water for rice cultivation. The main goals of this project are to decrease toxic arsenic (As) in the two most important sources of exposure, i.e. water and rice, and to determine i) how As can be removed efficiently from drinking water and ii) how As uptake by rice can be diminished in wet cultivation. In the first subproject, we will determine under which conditions drinking water filters in Vietnam efficiently remove As, how long the filters can be used, and whether toxic-levels of nitrate are formed in the filters. We will develop a visual indicator in the filter that allows the broad population to determine, without a need for sophisticated analytics or education, when the efficacy of the filters fails, due to saturation with As, and need replacement. We will also investigate how the As-loaded, used filter material can be disposed of without future risk. In the second subproject we will investigate whether the stimulation of nitrate-reducing, iron-oxidizing bacteria in paddy soil decreases As uptake by rice as a consequence of As-binding to the formed minerals. We will determine how defined nitrate addition can help to simultaneously minimize As uptake into the rice and the emission of the greenhouse gas N2O that is formed during microbial nitrate reduction. This project will provide practical solutions for people living in As-affected countries to reduce their exposure to As and nitrate, and to improve their health and living situation.

• DFG Programme: Research Grants