Human health risk and hydro-geochemical appraisal of groundwater in the southwest part of Bangladesh using GIS, water quality indices, and multivariate statistical approaches

This study investigated the groundwater chemistry, suitability, and potential human health risk in the southwest part of Bangladesh. Groundwater samples were collected from the shallow aquifer throughout the study area. A set of different hydro-chemical analyses, water quality indices, multivariate statistics, and geo-statistical models were applied to achieve the study objectives. Study results show the concentration of NH3-N, HCO3-, Ca-2(+), As, Fe, and Mn exceeded Bangladesh drinking water standards in 94%, 100%, 100%, 73%, 97%, and 91% of samples, respectively. Groundwater quality indices indicate that about 94% of samples are suitable for irrigation, and about 82% are unsuitable for drinking. In the study area, groundwater is mainly Ca2+-Mg-2-HCO3- types, and rock-water interactions dominate the mineralization process. Ca2+ > Mg2+ > Na+ > K+, and HCO3- > Cl- > SO42- are the sequential orders of major cation and major anion, respectively. Multivariate analyses show the geogenic origin is predominant over anthropogenic sources. Semivariogram models show moderate to weak spatial dependence. The non-carcinogenic and carcinogenic health risks via oral exposure pathways for adults and children are in the high (97%) and very high (100%) categories, respectively.