Groundwater quality and hydrogeochemical characterization of Khetri copper mining region, India

The impact of copper mine on groundwater quality in the semi-arid region is evaluated, and also characterized for hydrogeochemical processes. Groundwater samples (post monsoon and pre monsoon) from Khetri copper mine region of Rajasthan, India were studied. In majority of groundwater samples, the values of analyzed parameters such as EC, Ca2+, Mg2+, Na+, HCO3- and Cl- exceed the WHO (2011) and Bureau of Indian Standards (2012) permissible limits. Higher concentrations of ions were observed near the mining activities (mines, tailings, overburden rocks and abandoned mine) and in the downstream of groundwater flow from mines suggesting significant influence of mines on water quality. High concentration of major ions is attributed to oxidation of sulfides or acid mine drainage (AMD). The Gibbs plot for cations and anions as a function of TDS indicates the evolution of groundwater from rock-water interaction in both seasons. Thus, increased major ions concentration is due to dissolution of minerals by AMD.