Fluoride levels in Soil and Crops of Tomato and Onion Farms of Zanjan

Background: Fluoride is an essential nutrient for the human body. The major routes of fluoride intake include food and drinking water, though the absorption of fluoride from food is much easier. The aim of this study was to evaluate the amount of fluoride in the soil and tomato and onion crops on farms of Zanjan. Methods: Three farms of each crop (tomato and onion) were selected randomly. Each farm was divided into 10 sections, and one sample of soil and crop of each section was taken which means 120 samples in total. Fluoride concentrations in the soil and crops were measured using the Ion Selective Electrode (ISE) and repeated 3 times. Results: The mean concentration of fluoride in soil samples from studied farms in Zanjan was 0.83 ± 0.17 mg/kg. The mean concentrations of fluoride in tomatoes and onions of Zanjan were observed 2.10 ± 0.80 and 2.23 ± 0.64 mg/kg, respectively. Conclusion: There was no significant difference between fluoride concentration in tomatoes and onions, although there was a significant difference between the amount of fluoride in the soils of studied farms (Pv < 0.024). No significant correlation was observed between the fluoride levels of soils and the fluoride levels of tomatoes (R2 = 0.126) and onions (R2 = 0.008)