Groundwater quality and health risk assessment of nitrate and fluoride in Al Qaseem area, Saudi Arabia

Abstract

Abstract Groundwater serves as the lifeline in arid regions, where aquifer overuse and climatic factors can substantially degrade its quality, posing significant challenges. The current study examines the drinking water quality in the Al Qaseem area and assesses the potential health risks from nitrate ( NO 3 − {\text{NO}}_{3}^{-} ) and fluoride (F−) exposure to infants, children, and adults. This evaluation employs parameters such as the daily water intake, hazard quotient, and non-carcinogenic hazard index. Groundwater samples from 38 wells and boreholes were analyzed for major cations and anions. The water quality index and multivariate tools were utilized. The average concentrations of SO 4 2 − {\text{SO}}_{4}^{2-} , Cl–, Ca+, Na+, Mg2+, and K+ exceeded acceptable limits. Among the 38 samples, 8 were unsuitable for drinking, with 5 categorized as very poor quality, 10 as poor, 14 as good, and 1 as excellent. Nitrate levels ranged from 1.30 to 108.00 mg/L, with a mean of 36.56 mg/L. Three wells exceeded World Health Organization (WHO) guidelines (50.00 mg/L). Fluoride ranged from 0.10 to 0.98 mg/L, with a mean of 0.71 mg/L and none surpassing WHO recommendations (1.5 mg/L). The HI values for adults, children, and infants were 0.993, 2.606, and 2.78, respectively. About 57.89% of the water samples exceeded the safety level of 1 for adults and 94.73% for both children and infants. Thus, the groundwater in the study area may pose non-carcinogenic health risks to infants, children, and adults when used as drinking water.