Heavy metal contaminated soil, water, and vegetables in northeastern Iran: potential health risk factors.

Purpose: This study was designed to measure the concentrations of heavy (Pb, Cu, Fe, Ni, and Zn) metals in water, soil, and frequently edible leafy vegetables in the Iranian population and assessed the carcinogenic and non-carcinogenic health risk in consumers. Methods: The samples of soil, water, and vegetables were collected from forms near the Tehran-Mashhad highway in Neyshabur, Iran. The content of heavy metals in the samples was analyzed using Atomic Absorption Spectrophotometry. Results: The average concentrations of Pb, Cu, Fe, Ni, and Zn were 5.56, 3.35, 4.74, 2.95, and 5.27 mg/kg, respectively. Lead concentration in all of the vegetable samples was higher than the permissible value endorsed by the World Health Organization (WHO) / Food and Agriculture Organization (FAO). In contrast, the concentrations of all the other heavy metals in the samples were less than the maximum permissible levels recommended by WHO/FAO. Similarly, the water and soil samples were highly contaminated by Lead. The hazard quotient (HQ) of all the heavy metals was distinctively less than one, and it did not exceed 0.3 in any of the age groups. Furthermore, the carcinogenic risk for nickel was only higher than the recommended value, especially in women. Conclusion: While it seems that consuming vegetables has no acute health risk related to heavy metals, long-term and regular ingestion of the vegetables are likely to make cancer risk. Besides, due to the high concentration of Pb in soil and vegetables, regular and integrated assessment of heavy metals in soil, water, and food is necessary.