Assessment of Heavy Metal Contamination in Groundwater of Khetri Copper Mine Region,India and Health Risk Assessment

Abstract

The present study determines the abundance of heavy metals (Cu, Zn, Fe, Ni, Co, Mn and Pb) in the groundwater (pre and post monsoon) of the Khetri copper mine region, India and evaluates the pollution indices and risk assessment to assess the suitability of groundwater for human consumption. In majority of the groundwater samples, the concentration of heavy metals exceeds the desirable limits set by WHO, 2011 and Bureau of Indian Standards (BIS), 2012, whereas, average Fe concentration is 1.65 and 1.9 ppm during pre and post monsoon season respectively, which is above the BIS permissible limit (0.3 ppm) probably due to oxidation of iron-rich sulfides. Principal component analysis (PCA) and correlation matrix indicate a common source i.e. anthropogenic activity (mines) for Cu, Co, Ni and Mn. The calculated pollution indices namely contamination index (CI) and index of environmental risk (I_ER) for the heavy metals suggest that majority of the studied groundwater samples are in the slightly contaminated zone. However, a few of the samples close to mines, overburden rocks and tailings fall in the highly contaminated zone indicating their unsuitability for drinking purposes. The calculated hazard quotient for non-carcinogenic health effects is in the acceptable limit for all the groundwater samples except samples from Chaandmari (an abandoned mine), while the Health Index (HI) is in the medium range for all the samples barring a few samples.