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 mu s/cm, depth of 96.8 feet, and turbidity of 1.7 nephelometric turbidity units. The mean values of HCO3-, Ca2+, Mg2+, and Na+, were 289.5, 47.5, 30.6, and 283.3 mg/L, respectively. The mean values of SO42-, NO3-, K+, Cl-, and Fe2+, 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-HCO3 type and 46% were mixed CaNaHCO3 type. The saturation indices of the mineral phases reveal that the groundwater sources of the study area were saturated with CaCO3 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.

Automated summary

Fluoride contamination in drinking groundwater is a significant health risk in Pakistan. This study evaluated the health risk and suitability of elevated fluoride in groundwater for drinking purposes. The results showed that fluoride levels exceeded the WHO recommended limit, posing the greatest health risk to children. Additionally, the groundwater sources were found to be contaminated due to geological and anthropogenic actions.