Risk assessment of dietary exposure to cadmium and lead through wheat and rice consumption in Iran

Cadmium (Cd) and lead (Pb) are toxic metals associated with kidney damage, bone demineralization, and neurodevelopmental disorders. This study assessed their concentrations in Iranian wheat and rice and evaluated associated health risks. From 2018-2023, 2016 wheat and 285 rice samples were collected from major producing provinces. Risk assessment followed EFSA and U.S. EPA methodologies using probabilistic exposure modeling, Target Hazard Quotient (THQ), Tolerable Daily Intake (TDI), and Margin of Exposure (MOE). Mean Cd and Pb concentrations were 0.011 and 0.032 mg kg⁻¹ in wheat and 0.022 and 0.049 mg kg⁻¹ in rice, respectively. Exceedance rates of Iranian standards were low: 0.84 % (Cd) and 14 % (Pb) in wheat, and 1.34 % (Cd) and 0.20 % (Pb) in rice. Mean Cd exposures represented only 8.2-12.6 % of TDI, with the 99th percentile below 55 %. For Pb, MOE values exceeded 10 under current consumption patterns, indicating safety, but decreased to 1-10 under high wheat consumption scenarios, suggesting negligible to low concern risk. Sensitivity analysis identified wheat Pb concentration as the dominant risk driver (84.6 % of variance). These findings support evidence-based food safety management and emphasize the need for continuous monitoring of toxic metals in staple foods.