Systematic Review and Meta-analysis of Toxic Element Accumulation in Iranian Wheat Cultivation

The contamination of wheat with potentially toxic elements (PTEs) poses a significant public health concern, particularly in developing countries where industrial activities and unsustainable agricultural practices contribute to heavy metal accumulation. This systematic review and meta-analysis evaluated concentrations of inorganic arsenic (iAs), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) in wheat cultivated across Iran. Forty-five papers with 383 data reports from 1983 to 2023 were included in our study. The highest concentrations were found in Isfahan (iAs: 916.743 μg/kg), Chaharmahal and Bakhtiari (Cd: 884.113 μg/kg), Hamedan (Hg: 84.452 μg/kg), Tehran (Ni: 24,000 μg/kg), and Kurdistan (Pb: 2,115.454 μg/kg), surpassing international safety standards. Using the Target Hazard Quotient (THQ) indices, the study revealed significant noncarcinogenic and carcinogenic risks, especially for children. The findings emphasize the need for urgent measures to reduce PTE contamination, including rigorous monitoring of soil, water, and crop quality, sustainable farming practices, and improved wastewater management. Public awareness campaigns and targeted interventions are also critical in mitigating health risks associated with heavy metal exposure. These strategies aim to safeguard public health and reduce the burden of PTE-related health risks, particularly among vulnerable populations.