Health risk assessment of heavy metal contamination in groundwater of Kadava River Basin, Nashik, India

Abstract

Present research work emphasizes the integrated approach of heavy metal pollution indices coupled with multivariate statistical analysis to evaluate the health risk from groundwater of the Kadava River Basin. In view of this, forty representative groundwater samples were collected from dug and bore wells during pre-monsoon seasons of 2011 from rural habitations which are actively used for drinking and irrigation. The heavy metals viz., Pb, Cd, Zn, Fe, Mn, Cr, Cu, Co and Ni were analyzed through ICP-AES and compared with the BIS standards for drinking appropriateness. The analytical results exhibited that, Pb and Ni exceeded the maximum allowable concentration in all samples; while, Cr in 95% samples and Fe in 92.5% samples found beyond the safe limits. Heavy metal contamination assessment has been performed by using Heavy metal Pollution Index (HPI), Hazard Index (HI), Heavy metal Evaluation Index (HEI) and Degree of Contamination (Cd). The HPI results depicts that, 65 and 10% groundwater samples characterizes the medium and high pollution extent class. The human exposure risk based on HI confirms that groundwater is not suitable for drinking to all age groups as the value of HI ≥ 1. HEI results shows that 82.5% groundwater samples fall in high pollution extent category and only 17.5% samples in medium pollution extent category caused due to excessive presence heavy metals. Cd result illustrates the widespread unsuitability of 97.5% groundwater samples due to high pollution load from heavy metals and 2.5% samples comes under moderate pollution extent. The correlation among the heavy metal indices depicts that HPI with HEI (r = 1) and Cd (0.825); moreover. HEI with Cd (r = 0.825) are strongly associated; hence, it confirms that, all these indices are significant to assess the heavy metal contamination risk in the study area. PCA, CA, CM and pollution indices analysis corroborate that, high contents of heavy metals in groundwater of Kadava River Basin is owed to land use pattern, intense agriculture, leaching of fertilizers and pesticides and domestic waste into the aquifer system. The outcomes of research work may help to local planners and policy makers to prevent the health risk by the implementation of appropriate monitoring and mitigation measures for contaminated aquifers.