Monitoring of groundwater quality for drinking purposes using the WQI method and its health implications around inactive mines in Vemula-Vempalli region, Kadapa District, South India

Abstract

A study was conducted to evaluate the groundwater quality and health risk assessment for drinking purposes around inactive mining areas in the rural regions of Vemula-Vempalli region using the water quality index (WQI) method. For this study, forty groundwater samples were collected from bore wells and analyzed for physical parameters and major cations and anions followed by standard methods of APHA. From the analytical results, most of the groundwater samples are in alkaline nature; EC, TDS, and TH values are below the permissible limit and major cations (Ca2+, Mg2+, K+, Na+) & anions (Cl−, HCO3, SO42−, F−, NO3−) also within the permissible limit except fluoride and nitrate. Fluoride and nitrate in the groundwater range between 0.24–3 and 0.14–269 mg/L, respectively. Magmatic intrusions and water–rock interactions are main responsible for elevated fluoride in groundwater, and agricultural practices and usage of fertilizer are major responsible for higher nitrates in the groundwater. Piper diagram reveals that most of the samples belong to hydrochemical facies Ca2+–Mg2+–HCO3− category in this region. A higher concentration of fluoride and nitrate in the groundwater may cause a serious impact on human health. Non-carcinogenic effects of F− and NO3− were computed using total hazard index by adopting USEPA guidelines; THI values in drinking water range from 0.41 to 7.28 (adults), 0.41 to 7.38 (children) and 0.31 to 5.62 (infants); it reveals that children are more prone to the health impact than adults and infants. Overall assessment of WQI values (83.7–186.1 mg/L) shows that 7.5% (excellent), 80% (good), and 12.5% groundwater samples are very poor for drinking purpose in this region.