Assessing the geochemical processes controlling groundwater quality and their possible effect on human health in Patna, Bihar

Abstract

Abstract The current investigation primarily concerns groundwater potability and irrigational value in the urban area of Patna. Hydrogeochemical processes influence human health by controlling the quality of groundwater. In this research, we evaluated the interplay between several measures of groundwater quality, the various possible causes of groundwater pollution, and the resulting health risks. Twenty groundwater samples were taken from various locations and examined to determine the water quality. Groundwater and associated geochemical processes in the study area were analyzed using statistical methods, geochemical modelling, and graphical representations. The average EC of the groundwater in the examined area was 728.13 ± 331.84 µS/cm, with a range of around 300–1700 µS/cm. Positive loadings were seen for Total Dissolved Solid (TDS), Electrical Conductivity (EC), Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Chloride (Cl−), and Sulphate (SO42− ) in principal component analysis (PCA), demonstrating that these variables accounted for 61.78% of the total variance. In the groundwater samples, the following main cations are the most prevalent such as Na+ > Ca2+ > Mg2+ > K+, while the dominant anions are HCO3− > Cl− > SO42−. The elevated HCO3− and Na+ ions indicate that carbonate mineral dissolution might affect the study area. The result demonstrated that there are 70% of samples fall into the Na-Cl-SO4 type, 15% of samples fall into mixed Ca-Na-HCO3 type, and 5% of samples that fall into the mixed Ca-Mg-Cl type and Na-HCO3 type, and no samples that fall into the Ca-Cl type. The findings make it abundantly evident that the primary groundwater salinity is far higher than the secondary salinity produced because of the weathering of the bedrock. The presence of the NaHCO3 kind of water is suggestive of shallow meteoric water, which may have originated from the river Ganga that is located nearby. The interactions between water and rock could have naturally resulted in the creation of these clusters inside the aquifer matrix. The results show that a multivariate statistical analysis, graphical plots, and geochemical modelling successfully identify the parameters controlling groundwater quality.