Dietary Health Risk Assessment of Pesticide Residues in Pistachios Based on Probabilistic Modeling Techniques

Pistachio is an important agricultural commodity, and Iran is among the world’s leading manufacturers, exporters, and consumers. However, extensive pesticide application in pistachio groves is a source of concern regarding residual contamination in edible nuts. In the present study, 25 pistachio samples collected from Sirjan orchards were analyzed for pesticide residues by the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure followed by Gas Chromatography-Mass Spectrometry quantification. Five pesticides from three priority chemical classes—organophosphates (dichlorvos, dimethoate, ethion), organochlorines (DDT), and neonicotinoids (thiacloprid)—were present in concentrations ranging from 0.015 to 0.064 mg/kg. Residue concentrations were assessed against national and European Maximum Residue Limits (MRLs). Probabilistic health risk was assessed by a Monte Carlo Simulation to estimate non-carcinogenic and carcinogenic risks for children and adults. The 95th percentile of total hazard quotient was 1.471 in adults and 10.644 in children, indicating moderate to high risk of non-carcinogenicity, particularly in children due to their low body weight and high intake-to-weight ratio. Carcinogenic risk calculation of dichlorvos and DDT also exceeded the U.S. The EPA threshold level is 1 × 10−6, while children’s and adults’ total carcinogenic risk could reach 7.4 × 10−4 and 1.2 × 10−4, respectively. Pesticide concentration was identified as the greatest predictor of risk in a sensitivity analysis. The results urge the implementation of Good Agricultural Practices, frequent residue monitoring, and more stringent pesticide regulations to improve food safety and safeguard vulnerable populations, particularly children.