Assessment of Groundwater Quality in a Tidal River Basin of the Ganges Delta in Bangladesh

Abstract

At Shailmari River basin, located in the central \nGanges Delta and the southwestern coastal Bangladesh, groundwater is the only \npotable source for water supply due to incompatible surface water sources. \nHowever, salinity degradation along with arsenic and iron contamination poses a serious health threat to the basin \ncommunity. Considering this, an investigation was carried out along both \nbanks of the river to assess groundwater vulnerability and its quality for \ndrinking by conducting multi-seasonal water sampling campaigns from 20 domestic \nwells and analyses (both in-situ and laboratory) for several physico-chemical \n(pH, EC, TDS and major ions) and biological (coliforms) parameters. The results \nshow slightly alkaline groundwater in the study area with largely variable chemical composition, i.e. EC varies from around 1900 to 2700 μS/cm. The abundance of major ions indicates as Na+ > Ca2+ > Mg2+ > K+ for cations and \xa0> Cl- > \xa0> \xa0> \xa0for anions. As per the Canadian water quality index (CCMEWQI), almost all groundwater samples \nconcentrate in the marginal category meaning that groundwater is frequently \nthreatened. Besides, it is not fully safe for drinking as revealed from \ncomparison of geochemical data with national and WHO water quality standards.