Arsenic problem in Bangladesh
The foreign office states, that 663 Million people don‘t have access to clean water (as of 2015). Many factors can lead to a threat of drinking water. In a number of countries, arsenic poses a major health risk. A continuous intake can be carcinogenic among other things. Especially affected Asian countries are Bangladesh, India (West Bengal), and North-China (Smedley et al., 2002).
Internationally the high groundwater contamination in Bangladesh and West Bengal is recognized as a serious problem for the population (Smedley et al., 2002). In order to offer a drinking water supply free of bacteria, the government with the support of aid organizations, is trying to make groundwater nationwide accessible (Harvey et al., 2002). Measured As-concentrations in wells can reach amounts of mg/l, thus considerably exceeding the maximum WHO recommendation of 10µg/l. The national threshold in Bangladesh is 50µg/l (Nickson et al., 2000). Highest contamination occur in the S and SE of the country (Ravenscroft et al., 2003). The government of Bangladesh estimates that 29.24 Million people are affected by As-concentrations above 50µg/l (as of 2009, DPHE). In 2015, this will correspond to about 19% of the population.
Due to many years of experience, the research group Hydrogeochemistry and Hydrogeology of the Institute of Geosciences of the University of Heidelberg has profound knowledge about the behavior of As in the aquatic milieu and processes like oxidation, reduction, sorption and mobilization.
In September 2015, shallow groundwater in Bangladesh was analyzed during a measurement campaign. Investigated were three sites in the surroundings of Ullapara, about 120km WNW of Dhaka. During the field campaign, a number of water sources were recorded and tested for arsenic and other groundwater characterizing parameters. This first sampling was done at the end of the rainy season. A second measurement campaign in April 2016 was conducted to display possible seasonal variations of groundwater chemistry. Additionally, the sources of the As in the shallow groundwater supposed to be determined. Stationary investigations of the groundwater chemistry and the sediment composition provide insight into the behavior of As-species and their mobility in the subsurface.
The project included cooperation with the University of Dhaka and the College of Ullapara. Further collaborations to establish a data base and continuous monitoring of the As-concentrations are planned.
