Assessment of Heavy Metals in Potato and Onion Supplies in Rasht

Background: The entry of heavy metals into the food chain is an important environmental challenge for humans. Due to their potential for accumulating in the body, the different aspects of the hazard posed by heavy metals should be carefully examined. Objectives: The present study was conducted to determine the concentrations of heavy metals such as Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb), and Nickel (Ni) in tuber crops i.e., potatoes and onions in Rasht, north of Iran. Materials & Methods: A total of 140 potatoes and onions that were planted in difference cities of Iran were randomly procured from the city's fresh market in the spring during ten-day intervals. The acid digestion method was used for the preparation of the samples and the heavy metals were measured using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Results: The mean concentration of Pb, Cd, Cr, and Ni found in the potato samples were 0.057, 0.079, 0.299, and 0.190 mg/kg of dry weight, respectively. The mean concentration of Pb, Cd, Cr, and Ni found in the onion samples were 0.067, 0.020, 0.275, and 0.235 mg/kg of dry weight, respectively. In both products, the amount of As was less than the device’s detection limit (1.187 ppb). The mean concentration of heavy metals in the products received from the northern region was higher than the central and southern parts of Iran. Conclusion: The results of this study showed that the mean concentration of Pb in both potatoes and onions were in the normal range. Similarly, the mean concentration of Cd, in onions was under the standard limit, but it was higher than the standard limit in some potato samples. Also, the mean concentration of Cr was higher than the standard limit.