Evaluating health risks from the release of trace elements to groundwater by rock-water interaction in a weathered gneissic aquifer

Abstract

High concentration of trace elements in groundwater poses more health risks to humans by drinking groundwater and dermal contact. This work aimed to assess the trace element concentration in groundwater, water quality for drinking purposes, and its effect on human health upon prolonged consumption. The study was carried out in the gneissic terrain of Perambalur District, Tamil Nadu, India, where groundwater is used mainly for drinking, agricultural, and domestic purposes. Hydrochemistry, water quality, and health risk assessments of trace elements from 44 groundwater samples for pre- and post-monsoon were determined by drinking water quality, hazard quotient, hazard index, and carcinogenic risk. The dominance of trace elements in groundwater was in the order of Zn > Fe > Cu > Ni > Te > Pb > Co. Ni and Co are released more during the post-monsoon, and Zn, Fe, Cu, and Pb concentration during the pre-monsoon. The dominant type of groundwater was Ca-HCO3 and mixed Ca-Mg-Cl type. The dissolution of fissile hornblende biotite gneissic rock dissolves more trace elements to groundwater than charnockite rock. The correlation matrix indicates that major ion and trace elements were positively good in groundwater during the pre-monsoon and post-monsoon 2018. The principal component analysis suggests that the weathering of rocks, rainwater recharge, and evaporation processes controlled the hydrochemistry of trace and major ions. The concentration of Pb, Ni, and Cd elements exceeded the permissible limit of BIS and WHO; these elements are unsuitable for drinking. The trace element concentration in groundwater was good for drinking and irrigation in the study area, except in a few wells. The hazard quotient and hazard index were computed, which revealed that non-carcinogenic risk to human health by drinking groundwater was more of a problem for children than adults. This study will help prevent children from health risks of trace elements.

Keywords: Carcinogenic risk; Drinking; Groundwater; Hazard index; Perambalur; Principal component analysis; Southern India; Trace element.