Evaluation of the groundwater quality index (GWQI) and the human health risk (HHR) on fluoride concentration in Namakkal district, South India

This research aims to determine the health consequences of fluoride contamination of groundwater in the Namakkal region in south India using the groundwater quality index (GWQI). Study area latitude and longitude: 11° 00' and 11° 30' in the north, and 77° 45' and 78° 15' in the east. Statewide, it is among the largest districts in the state. The study region occupies an area of 3406.37 km2. The geology of the studied area is mainly based on the Archaean crystalline and metamorphic complex. The district's major aquifer systems are composed of crystalline rocks that are weathered and fractured and of colluvial deposits.  Alluvium and colluvium are examples of porous formations in the cross-section. Only the main river channels have alluvial deposits. The phreatic properties of groundwater Depending on the topography, these aquifers may reach 5 m saturation thickness. Groundwater samples were obtained from 58 bore well sites across the study area during the North-East Monsoon (NEM) of 2015. pH concentrations in suitable drinking water regions during the seasons assist in limiting the availability of groundwater for drinking purposes. TDS are an important factor in determining water suitability for various purposes. The groundwater sample in the study area shows cation domination in ascending order of Na+ > Ca2+ > Mg2+ > K+ due to the dissolution of aquifer minerals in rainfall in the study area. In the NEM seasons, rock dominance and anthropogenic contributions to higher Na+ > Mg2+ > Ca2+ > K+ values. Fluoride concentration differentiates into three groups such as < 0.5 indicates low risk, 0.5 to 1.5 indicates moderate risk, and > 1.5 means high risk. More than 2 fluoride implies very high risk, whereas fluoride in the range of 1.5 to 2.24 suggests a very high risk. The appraisal of non-carcinogenic risk was done to stress the health issues that succeed due to the intake and dermal contact of drinking water in the Namakkal district. The percentage of risk HQ >1 shows that 48 men groundwater samples, followed by 46 groundwater samples women and 30 groundwater samples children, constitute possible health hazards. Overall, health risk estimation results showed that all the groundwater samples have surpassed the permissible limit of HQ <1 for children.