Northwest of Iran as an endemic area in terms of fluoride contamination: a case study on the correlation of fluoride concentration with physicochemical characteristics of groundwater sources in Showt

Abstract

Fluoride in drinking water is an important chemical species with regard to public health considerations, although a fluoride concentration of about 1.5 mg L-1 in drinking water can decrease tooth decay and higher concentrations cause health problems. The concentration of fluoride in water is affected by some chemical characteristics. This study aimed to evaluate the relationship between fluoride and other chemical parameters (pH, Turbidity, EC, TDS, TH, ALK, Cl-, SO 4 2-, NO3-, NO2-, Ca2+, Mg2+, Na+, K+, PO 4 3-) in water bodies located in Showt, West Azerbaijan Province, Iran. Sample preparation and analysis were performed according to standard methods. A wide range of fluoride concentrations was measured in this study (0.0-5.5 mg L-1). The results indicated that alkalinity and Na+ have a significant positive relationship with fluoride concentrations in water wells. Nevertheless, total hardness (TH) showed an inverse relationship with fluoride concentration. In addition, for a one-unit increase in alkalinity and Na+ concentration, the average amount of fluoride in water increased by 0.0028 and 0.16, respectively. Furthermore, for a one-unit increase in total hardness, the average amount of fluoride in water decreased by 0.005. In conclusion, fluoride concentration was affected by numerous factors such as hardness, alkalinity, and Na+ concentration. The findings of this study suggest that a suitable treatment of the groundwater is needed in contaminated areas before its use for drinking.