Groundwater quality evaluation using water quality index (WQI) for drinking purposes and human health risk (HHR) assessment in an agricultural region of Nanganur, south India

An effort has been made to understand the groundwater quality of Nanganur region for drinking purpose utilizing water quality index (WQI). Nitrate contamination in groundwater was assessed and the associated health risks to rural populations were estimated for different age groups, infants, children and adults in the agricultural region of Nanganur, South India, where residents rely on only groundwater for drinking use. Groundwater was slightly alkaline and moderately hard. The concentration of nitrate in the groundwater ranged from 25 to 198 mg/L, with a mean of 66.14 mg/L, and 61% of groundwater samples exceeded the World Health Organization (WHO) safe limit of 50 mg/L. The WQI values ranged from 92 to 295, with an average of 153, and about 86% of groundwater samples were poor quality for drinking uses. Results showed that the non-carcinogenic health risk for adults ranged from 6.0E-01 to 4.8E+00, for children 8.1E-01 to 6.4E+00, and for infants 9.4E-01 to 7.4E+00, respectively. Health risk caused by excessive intake of nitrate contaminated groundwater for children and infants were 1.15 and 1.75 times larger than that for adults, which suggested that health risk degree of infants have greater health risk than children and adults in the study region. The order of nitrate contribution to non-carcinogenic health risk among the studied age groups was infants > children > adults. Therefore, health risk reduction measures should be implemented to reduce exposure to nitrate contaminated drinking water in the study region.