Temporal and spatial variation of drinking water quality in a number of Divandareh villages, Iran: With emphasis on fluoride distribution

Fluoride is found in all water resources at different concentrations and drinking water is the major source of fluoride exposure. Thus, because of the adverse effect of fluoride in low and high concentrations, the evaluation of its content in drinking water is necessary. In the present study, the temporal variations and spatial distribution of fluoride concentrations in the drinking water of villages in Divandareh (Kurdistan, Iran) were determined. Thus, 30 villages were selected and 180 groundwater samples were taken in 2 dry and wet seasons in the year of 2013. The concentrations of fluoride and other anions were measured using the ion chromatography (IC) method. Geospatial analysis of the data was performed using the ArcGIS geographical information system (GIS) software. The results showed that the average fluoride concentration in drinking water ranged from 0.136 to 0.736 mg/l; 90.56% of samples had a concentration less than 0.50 mg F/l, and the rest had concentrations between 0.51 and 1.0 mg F/L. Based on the results of the nonparametric Wilcoxon test, a significant difference was found between the concentrations of fluoride in the two-stage sampling (P