Highly contaminated groundwater can affect the human health and constrain the economic development of a country. For this study 105 groundwater samples were collected in rock-dominant semi-arid (RDSA) region, India and analyzed for hydrochemical parameters including major ions, fluoride, and nitrate. The human health risks due to groundwater fluoride and nitrate contamination were also assessed. The analysis reveals that most of the groundwater samples are alkaline in nature. Hydrochemical types of groundwater in the study area are mainly Ca∙Mg–HCO₃ and Na–HCO₃ types and a few samples belong to Ca∙Mg–Cl and Na–Cl types in the RDSA region. Fluoride concentration ranges from 0.5 to 3.5 mg/L, and predominantly eastern part of the study region has higher concentrations of fluoride with comparison to the western part. About 49% of the groundwater samples have fluoride concentration above 1.5 mg/L in groundwater, indicating a high health risk to residents. Eventually, water-rock interactions are the main processes to elevate the fluoride concentration in eastern part of the study area. Nitrate concentration ranges from 12 to 212 mg/L, and northern and southern parts of the study region have much higher nitrate concentrations than the central region of the study area, where nitrate concentration is below 45 mg/L. In terms of nitrate, 55% and 17% of the groundwater samples are under high risk and very high risk categories, respectively, which are not suitable for drinking purposes in the study region. Fertilizer application for crop yields could be one of the reasons for elevated nitrate concentration. The total hazard index for adults ranges from 0.87 to 7.08, and for children 1.17 to 9.57, which suggests that children are at higher health risk than adults in the study region. Therefore, contaminants filters and rainwater harvesting are suggested as measures to reduce the health risk in the area.

The main aim of this study was to assess the groundwater quality and human health risks of fluoride and nitrate contamination in Nirmal Province, South India, where groundwater is the primary source for drinking water. Hazard quotient (HQ) and total hazard index (THI) were calculated to estimate the non-carcinogenic risk to men, women, and children using the most substantial method recommended by United States Environmental Protection Agency (USEPA). The results of the study reveal that 26% and 20.59% of groundwater samples have significantly high nitrate and fluoride concentrations, exceeding the maximum permissible limits set by Bureau of Indian Standards (45 mg/L and 1.5 mg/L, respectively). Therefore, ingestion of high fluoride and nitrate water could be the chief reason for health risk in the study region. The total non-carcinogenic health risks for men, women, and children ranged from 2.95E−01 to 4.07E+00, 3.49E−01 to 4.80E+00, and 3.99E−01 to 5.50E+00, respectively. Moreover, 67.65%, 79.41%, and 82.35% of the total collected groundwater samples exceeded the permissible limit for acceptable total health index (THI = 1) for men, women, and children, respectively. Therefore, the health risk assessment suggests that children face higher health risk than men and women in the study region.