Bioaccessibility and Health Risk Assessment of Heavy Metals in Commercially Available Rice from Central Iran: Implications for Food Safety.

Total concentrations of cadmium (Cd), lead (Pb), and arsenic (As) in commercial rice varieties from Kashan, Iran, were measured via ICP-OES, with bioaccessibility assessed using an in vitro gastrointestinal digestion model. Results indicated that Cd levels (0.051-0.068 mg/kg) exceeded the FAO/WHO limit but were close to the Iranian standard. Pb concentrations (0.258-0.62 mg/kg) surpassed both national and international limits, while As levels (0.018-0.028 mg/kg) remained below permissible thresholds. Bioaccessibility ranged from 29% to 55% for Cd, 38%-43% for Pb, and 42%-61% for As, indicating that only a fraction of the metals is released during digestion. Health risk assessment showed Hazard Quotients (HQ) for individual metals below 1, suggesting no significant non-carcinogenic risk. Lifetime Cancer Risk (LCR) values for Cd and As were within acceptable limits (10⁻⁶ to 10⁻⁴). It is concluded that although total concentrations of Cd and Pb exceed regulatory standards, their low bioaccessibility significantly reduces potential health risks under typical consumption patterns.