Human health risk assessment for fluoride and nitrate contamination in the groundwater: a case study from the east coast of Tamil Nadu and Puducherry, India

Consumption of contaminated groundwater leads to serious health problems and may restrain the socio-economic development of society. The study aims to estimate the groundwater contamination and human health risks induced by fluoride and nitrate along the east coast of Tamil Nadu and Pondicherry, south India. Sixty-six samples were collected from the study site to test the level of groundwater contamination. The pH revealed acidic to alkaline water samples, and chemical analysis suggests excess F? and NO3? in few sites. The major water types in the area are Ca-Cl, Ca-HCO3, and mixed Ca-Mg-Cl. Rock-water interaction is the vital process influencing water chemistry. Hydrogeochemical processes such as reverse ion exchange, ion exchange, mineral dissolution, and silicate weathering control the concentration of ions. Human interventions are also accountable for the supply of toxic contaminants in the groundwater system. The fluoride and nitrate concentrations reported a maximum of 1.78 and 100.0 mg/L, respectively. Elevated fluoride values were reported from the southern, central, and northwestern parts, whereas nitrate concentration was noted towards the southwestern, central, and northeastern parts of the study area. The non-carcinogenic risks to different age groups such as children, females, and males were estimated by calculating hazard quotient (HQ) and total hazard index (THI). Based on THI, 59.09, 51.52, and 34.85% of the child, female and male populations respectively, are under health risk. The study concludes that child and female categories are more vulnerable to health risks in comparison with males. The study's findings may help to take adequate measurements to control the potential health risk in the future.