Evaluation of fluoride contamination in groundwater and its non-carcinogenic health hazards in a drought-prone river basin of South India

The present work emphasizes the extend of groundwater pollution in Nagavathi River basin, south India and to study the potential health risks pertaining to the population there. Sixty-eight groundwater samples were collected and tested for various parameters such as pH, EC, TDS, major anions and major cations. The findings infer that the pH of the water ranges from 6.98 to 8.11, indicating that water is alkaline. TDS maximum value of 2401 mg/l indicates the presence of contaminants in the groundwater, and the electrical conductivity of 39.3% samples are above the range of drinking water standards. Based on Piper's diagram, 70.5% of the water samples are mixed CaMgCl type. The samples are classified as rock dominance in Gibb's diagram, which highlights the relationship between rock chemistry and water composition. The Entropy Water Quality Index (EWQI) was computed to calculate the quality of the water, which exhibits 25% of samples represent excellent to good quality, and 29% of samples represent poor water quality. From the spatial distribution map of fluoride, 16.17% of the samples are in the category of extreme risk with >4 mg/l, which can cause detrimental health issues according to WHO. From the outcomes, it is observed that the Total Hazard Index (THI) values for infants, children, teens, females, males were greater than 1. All the age groups in this region are affected due to fluoride, particularly infants and children are more affected. Proper geochemical investigations and treatment of water before consumption are recommended for the study area. In addition, health hazards due to groundwater contamination must be meticulously studied in future.