The heavy metal levels in six walnut cultivars from five geographical zones of Iran were measured. An assessment of risks was conducted by calculating the Target Hazard Quotient (THQ) and Incremental Lifetime Cancer Risk (ILCR) by use of the Monte Carlo simulation method. The highest amounts of As and Pb were reported in Farouj samples. Also, the highest levels of Cr, Zn, Cu and Mn were determined in samples collected from Tuyserkan. Accordingly, 50th and 95th ILCRs for general population due to consumption of walnut were 1.03 × 10-4 and 3.11 × 10-4 (for As), 4.10 × 10-6 and 1.1 × 10-5 (for Cr) and 4.71 × 10-9 and 1.05 × 10-8 (for Pb), respectively. In addition, the 50th and 95th centiles of the HIs for walnut ingestion by Iranians were 1.02 and 2.05, respectively, indicating a minor chance of non-cancer effects. Based on the calculated 95% ILCR, dietary exposure to As through the consumption of walnut poses a risk to Iranian consumer health. However, ILCR values of other heavy metals (HMs) were in acceptable ranges (ILCR < 1 × 10-4), representing no toxicological concern for consumers. The most significantly influential parameters were determined by sensitivity analysis during the MCS. According to THQ and ILCR methods, concentration was the most sensitive parameters. For THQ method the concentration effects were ranged from 72.4 to 85.1%. Moreover, for ILCR method the effects of concentration in As, Cr, and Pb were 87.1, 79.1 and 83.54%, respectively.
Keywords: Carcinogenicity; Food toxicity; Heavy metals; Non-carcinogenicity; Risk assessment; Walnut.