Concentration of cadmium, arsenic, and lead in rice (Oryza sativa) and probabilistic health risk assessment: A case study in Hormozgan province, Iran

Background: The presence of toxic heavy metals in cereal grains like rice is one of the main human and environmental health concerns. Their importance is because of their non-biodegradability nature, high half-time, and bioaccumulation ability in the human body. Among heavy metals, cadmium (Cd), lead (Pb), and arsenic (As) are most critical, so their concentrations in rice were evaluated in this study.  Methods: In this study, the concentration of Cd and Pb was determined by graphite-furnace atomic absorption spectrometer (GF-AAS), while the concentration of As was measured by atomic spectrum poll after acid digestion of the milled rice samples. The probabilistic health risk assessment of Cd, As, and Pb through consumption of different types of rice including local rice and two types imported from India (IND) and Pakistan (PAK), was estimated for the adults in Hormozgan province using Monte Carlo simulation (MCS) technique.  Results: It was revealed that the concentrations of all Cd, As, and Pb in the local rice samples were lower than those in the PAK and IND samples. The average concentration of As, Pb, and Cd in the rice samples were 0.045, 0.057, and 0.022 mg/kg, respectively. The estimated total target hazard quotient (TTHQ) for this population was lower than 1, representing negligible non-carcinogenic risk through rice consumption. However, total carcinogenic risk (TCR) via As intake showed a considerable carcinogenic risk (TCR > 1E-4) for this population.  Conclusion: According to the results, it is necessary to perform continuous monitoring for concentration of Cd, As, and Pb especially in the imported rice samples.