Evaluation of fluoride concentration at inlet and outlet household water treatment systems and bottled water distributive high consumption Ardabil city, Iran

Fluoride is needed for better health, but it can cause adverse health effects if used at higher levels. There are different sources for the uptake of the fluoride, and drinking water is its primary resource. The aim of this study is the evaluation of fluoride concentration at the inlet and outlet of household water treatment systems and highly consumed bottled water distributed in Ardabil city in 2020. This descriptive cross-sectional study was performed on 60 water samples (30 samples of bottled water from 10 distribution brands of Ardabil city and 30 samples of inlet and outlet of household water treatment system). The concentration of fluoride was measured using the SPADNS standard method and spectrophotometer techniques. The SPSS version 22 software was used for analyzing the data. The concentration of fluoride in all samples was obtained to be in the range of 0 to 0.87 mg.l^-1, with an average of 0.35 mg.l^-1, which was less than the standard. According to the results, the concentration of fluoride in the studied groups was significantly different (P = 0.001). Moreover, the efficiency of the household water treatment system in the reduction of fluoride was observed to be 67.25%. Although the concentration of fluoride in most samples was lower than standard, further studies on other sources of fluoride, such as vegetables, tea, and so on, are required for accurate comment on fluoride deficiency in drinking water of one area.