Contamination levels and health risk assessment of heavy metals in edible leafy vegetables distributed in Rafsanjan, southeast Iran

This study aimed to determine the concentrations of heavy metals and assess the health risk associated with their exposure through the consumption of Edible Leafy Vegetables (ELVs) distributed in Rafsanjan, the southeast area of Iran. In this study, samples of commonly consumed ELVs, including Coriander, Parsley, Persian Leek, Radish, Basil, and Lettuce, were collected over four seasons in 2024. Inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify the concentration of heavy metals lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), iron (Fe), manganese (Mn), and zinc (Zn). The concentration of toxic heavy metals was observed for As in Leek during the summer (16.33 ± 1.21 mg/kg), Cr in Lettuce during the winter (13.21 ± 1.16 mg/kg), and Pb in Radish during the summer (6.10 ± 1.33 mg/kg). The overall order of toxic heavy metal concentrations in the samples was As ˃ Cr ˃ Pb ˃ Ni ˃ Cd, and the most contaminated ELVs were ranked Leek ˃ Lettuce ˃ Radish ˃ Parsley ˃ Basil ˃ Coriander. The highest hazard quotient (HQ) value was recorded for As in Leek (4.8733 in children, 4.6993 in adults), AS Lettuce (1.3689 in children, 1.2571 in adults), and Cr in Lettuce (1.6139 in children, 1.4821 in adults). The highest hazard index (HI) values were observed for Leek, followed by Lettuce and Basil. In addition, the highest carcinogenic risk (CR) values were associated with Cr in Lettuce, As in Leek, and Cr in Basil, respectively. Therefore, continuous monitoring of heavy metals, particularly As and Cr in ELVs, is recommended to identify and mitigate contamination sources.