Non-Carcinogenic Health Risk Evaluation of Elevated Fluoride in Groundwater and Its Suitability Assessment for Drinking Purposes Based on Water Quality Index

Fluoride (F − ) contamination in drinking groundwater is a significant human health risk in Pakistan. Moreover, high fluoride pollution in drinking water causes a variety of disorders, including dental, neurological, and skeletal fluorosis. The aim of this research was to evaluate the health risk of elevated fluoride in groundwater and its suitability assessment for drinking purposes. The total of ( n = 37) samples were collected from community tube wells of Quetta Valley, Balochistan, Pakistan. The results show a mean pH value of 7.7, TDS of 404.6 mg/L, EC of 500 µs/cm, depth of 96.8 feet, and turbidity of 1.7 nephelometric turbidity units. The mean values of HCO 3 − , Ca 2+ , Mg 2+ , and Na + , were 289.5, 47.5, 30.6, and 283.3 mg/L, respectively. The mean values of SO 4 2− , NO 3 − , K + , Cl − , and Fe 2+ , were 34.9, 1.0, 1.6, 25.6, and 0.01 mg/L, respectively. The F − concentration in the groundwater varied between 0.19 and 6.21, with a mean value of 1.8 mg/L, and 18 samples out of 37 were beyond the WHO recommended limit of 1.5 mg/L. The hydrochemical analysis results indicated that among the groundwater samples of the study area, 54% samples were Na-HCO 3 type and 46% were mixed CaNaHCO 3 type. The saturation indices of the mineral phases reveal that the groundwater sources of the study area were saturated with CaCO 3 and halide minerals due to their positive (SI) values. Such minerals include calcite, dolomite, gypsum, and fluorite. The principal component analysis results reveal that the groundwater sources of the study area are contaminated due to geological and anthropogenic actions. The health risk assessment results of the F − concentrations show the ranges of ADD ingestion for children, females, and males in the Quetta Valley, and their mean values were observed to be 0.093052, 0.068825, and 0.065071, respectively. The HQ ingestion mean values were 1.55086, 1.147089, and 1.084521 for children, females, and males, respectively. It was noticed that children had the highest maximum and average values of ADD ingestion and HQ ingestion in the research area, indicating that groundwater fluoride intake poses the greatest health risk to children. The water quality index (WQI) analyses show that 44% of the samples belong to the poor-quality category, 49% were of good quality, and 8% of the samples of the study area belong to the excellent category.