Human health risk and water quality assessment due to fluoride and nitrate around Cauvery River basin, southern India.

Good quality water for human consumption, irrigation, and industrial use is very important. Today, around the world, water is contaminated by natural processes and human activities. This study aimed to evaluate the suitability of groundwater for drinking and irrigation, identify the source of fluoride and nitrate contamination, and assess the human health risks around the Cauvery River basin in southern India. A total of 30 groundwater samples were collected and analyzed for hydrochemical parameters, including EC, TDS, pH, Ca, Mg, Na, K, HCO, Cl, SO, NO, and F. The majority of groundwater samples in the study area are used for drinking and irrigation. The pH of groundwater in the study area was observed to be dominantly alkaline. The levels of TDS, Ca, Na, K, F, and TH exceeded the permissible limits recommended by BIS and WHO. Fluoride and nitrate levels in groundwater exceeded the permissible limits for drinking purposes in 43% and 50% of the samples, respectively. The excessive concentration of fluoride and nitrate in groundwater could pose serious human health problems. Fluoride and nitrate concentrations in groundwater vary between 0.1 and 2 mg/l and 12 and 95 mg/l, respectively. Based on the computation of the drinking water quality index, about 73% of groundwater samples were classified as excellent to good. Health risk was assessed for infants, children, and adults using non-carcinogenic risk indices such as hazard quotients (HQ), hazard indexes (HI), total hazard indices (THI), and carcinogenic risk indices (CR). Infants, children, and adults have different total hazards indexes ranging from 1.508 to 5.733, 1.579 to 6.003, and 0.011 to 0.046, respectively. Health risk assessment results indicated that the hazard index and hazard quotient were above the recommended limit of > 1 in most of the samples for infants and children. Non-carcinogenic risk and carcinogenic risks were more likely to affect infants and children rather than adults through ingestion of contaminated water.