Background and Objective: The contamination of soils and plants with heavy metals is a serious and growing problem. The present study aimed to determine the concentration of heavy metals in soil and some agricultural products and the probability of risks due to their consumption.
Materials and Methods: This cross-sectional descriptive study was performed using random sampling at harvest time in 2014 on 205 samples of vegetable crops (Leek, chard, parsley, watermelon, melon, tomatoes, cucumber, potatoes, onion, garlic, radish, green peas, and broad bean) and 129 samples of soils under cultivation. Concentrations of Cu, Zn, Cd, and Pb in soil and plant samples were determined by an atomic absorption instrument and the data was analyzed using SPSS software.
Results: There were significant differences between the mean concentrations of Pb, Cu, and Zn for different vegetables (P<0.001), but no significant difference was observed for Cd. The highest mean levels of Pb, Cd, Cu, and Zn were detected in parsley, chard, broad bean, and leek respectively. However, there was no heavy metal pollution in the remainder of the vegetables and soil samples (with the exception of agricultural soils adjacent to the lead mine of Mahneshan area) studied. Hazard probability (HQ) of each element for cancerous diseases was less than unit and the intake of heavy metals was lower than the Provisional Tolerable Daily Intake (PTDI).
Conclusion: The results of this study indicated that major accumulation of heavy metals was obtained in leafy vegetables. Therefore, much attention should be paid to consumption of leafy vegetables, especially vegetables grown in the surrounding industrial areas.
