Metal contaminants in rice imported to Iran: A comprehensive assessment of carcinogenic and non-carcinogenic health risks

Abstract

Background

Rice is a staple food in Iran, where significant imports from India and Pakistan are necessary to meet demand. However, imported rice has been found to contain harmful levels of heavy metals, posing health risks.

Objectives

This study aimed to assess the levels of 34 metals in imported rice and evaluated the associated health risks for the Iranian population.

Methods

Sixty samples of rice imported into the Iranian market from India, Pakistan, and Thailand were analyzed for 34 metals using inductively coupled plasma optical emission spectrometry (ICP-OES). The metals included carcinogenic elements-Arsenic (As), Lead (Pb), Nickel (Ni), and Cadmium (Cd)-and non-carcinogenic: Sodium (Na), Iron (Fe), Potassium (K), Calcium (Ca), Copper (Cu), Zinc (Zn), Magnesium (Mg), Platinum (Pt), Silicon (Si), Gold (Au), Boron (B), Bismuth (Bi), Tungsten (W), Tin (Sn), Molybdenum (Mo), Chromium (Cr), Barium (Ba), Strontium (Sr), Aluminum (Al), Selenium (Se), Manganese (Mn), Cobalt (Co), Antimony (Sb), Titanium (Ti), Lanthanum (La), Lithium (Li), Vanadium (V), Beryllium (Be), Palladium (Pd), and Mercury (Hg). The health risks associated with the consumption of rice were assessed through the Target Hazard Quotient (THQ), Hazard Index (HI), Incremental Lifetime Cancer Risk (ILCR), cumulative cancer risk (∑ILCR), and Margin of Exposure (MOE) approaches.

Results

The analysis revealed that the Cd level in 1 sample and Pb levels in 5 samples exceeded the maximum concentrations established by the Institute of Standards and Industrial Research of Iran. The risk of cancer in adults exposed to As and Cd at mean concentrations was found to be higher than 1 in 100,000, while for Pb and Ni, the risk was greater than 1 in 10,000. In children, the ILCR for As and Cd at mean concentrations exceeded 10⁻⁴, indicating a moderate risk level, and for Pb and Ni, it reached 1 in 1000, emphasizing the need for enhanced public health safety measures. Additionally, ∑ILCR from all metals in both adults and children exceeded the 10⁻⁴ threshold. The MOE values for mean, median, and 90th percentile exposure to As, Pb, and Ni were below 10,000 in adults and children, indicating a significant health concern from rice consumption.

Conclusion

These findings highlight the potential health risks of consuming rice contaminated with heavy metals, particularly arsenic. Therefore, special attention should be directed towards monitoring and reducing toxic metal levels in imported rice, with interventions aimed at mitigating these risks.