Hydrogeochemical Characterization and Assessment of Groundwater

Sixty-one groundwater samples were collected from the hard rock terrain of Nanganur region of South India, were evaluated for hydrogeochemistry as well as groundwater quality for drinking and irrigation purposes. Additionally, the probabilistic non-carcinogenic human health risks associated with fluoride and nitrate concentrations were assessed using the US Environmental Protection Agency (USEPA) mathematical model. The hydrogeochemical facies, i.e. Ca2+-Mg2+-SO42- and Na+-Cl--SO42-, identified are result of weathering and dissolution of rocks, ion exchange between Ca2+ and Na+, and precipitation of CaCO3, and also due to influences of anthropogenic sources. Molar ratio Na+/Cl-, and distributions of Ca2++Mg2+ versus HCO3-+SO42-, Ca2++Mg2+ versus TC, and Na++K+ versus TC indicate that silicate weathering is the prime source for the ions. Gibbs diagram also suggests that rock-water interaction is the primary process of ionic concentrations in this groundwater system. As per the classification based on US salinity diagram, 18% groundwater samples show medium salinity and low sodium hazards and 73% of, them have high salinity and low sodium hazards.