Heavy Metal Contamination in Wheat Grains: Spatial Analysis and Health Risk Assessment in Southern Iran

The present study addresses the critical issue of heavy metal contamination in wheat grains, aiming to bridge the existing research gap by examining the spatial distribution of heavy metals and assessing their potential health risks in the southern Iranian oil fields. Employing a quantitative approach, we collected samples from 50 regional wheat cultivation farms and analyzed the concentrations of chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) using inductively coupled plasma‒mass spectrometry. Our findings revealed concerning levels of heavy metals, with Zn exhibiting the highest concentration (mean: 30.169 mg/kg), while Pb and Hg exceeded the FAO/WHO safety thresholds. Among the studied elements, Hg posed the highest health risk, with health quotient (HQ) values of 1.38 for adults and 2.14 for children. Cr (HQ: 0.000236 for adults; 0.00038 for children), followed by As (HQ: 0.000494 for adults; 0.00076 for children), was identified as the primary carcinogenic heavy metal. Principal component analysis (PCA) revealed that the first factor accounted for 48% of the total variance, primarily attributed to As, Cr, Pb, and Hg, while the second factor explained 27.32%, associated with Cd, Zn, and Cu. Ordinary kriging interpolation indicated elevated heavy metal concentrations in farms located in the eastern, northeastern, and southwestern regions. Based on these findings, we emphasize the urgent need for remediation strategies to reduce heavy metal contamination in wheat grains, highlighting the crucial importance of ensuring food safety and protecting public health.