Groundwater chemistry integrating the pollution index of groundwater and evaluation of potential human health risk: A case study from hard rock terrain of south India.

Groundwater is an important resource for drinking and irrigation purposes and also the significant route of human exposure in most of the arid and semi-arid regions of the world. In view of this, 43 groundwater samples were collected and analyzed for various physico-chemical parameters. Particularly, this study integrates the groundwater contamination by comparing it to national guidelines and the impact of fluoride and nitrate on health risk were quantified through the model recommended by the United States Environmental Protection Agency (USEPA). The groundwater of the investigated region is slightly alkaline in nature with hydrochemical facies of groundwater is predominantly characterized by Ca2+-Mg2+-HCO3- and Ca2+-Mg2+-Cl- water types. The results show that the concentrations of groundwater nitrate and fluoride range from 2.2 to 165 mg/L and 0.84 to 4.3 mg/L, and 55.81% and 65% of groundwater exceed the national guidelines for drinking purposes, respectively. The pollution index of the groundwater (PIG) method unveiled that low quality and moderate quality of water account for 40% and 4.65% of collected groundwater samples, respectively. The results of non-carcinogenic health risk ranged from 0.63 to 5.31 ± 2.59 for adults, 0.85 to 7.18 ± 3.50 for children and 0.98 to 8.29 ± 4.04 for infants, indicating health risk was higher in infants and children as compared to the adults in the study region.