Pollution status and exposure risk assessment of heavy metals in vegetables in Zibo City

Objective To analyze the contamination of arsenic(As), cadmium(Cd), lead(Pb) and mercury(Hg) in vegetables in Zibo City, evaluate the human health risk of heavy metals from feeding pathways. Methods The contents of As, Cd, Pb and Hg in 612 samples of leaf vegetable, root vegetable, fruit vegetable and stem vegetable from 2015-2019 were determined and analyzed. The pollution index method, target hazard quotient method and Pearson correlation analysis were used to determine the degree of heavy metal contamination, the health risk of exposed population and the similarity of source. Results The average content of heavy metals in vegetables from high to low was Pb>As>Cd>Hg. The contents of Cd and Pb were the highest in leaf vegetable, and the content and detection rate of As was the highest in stem vegetables. The over-standard rate of Cd in leaf vegetable and fruit vegetable was 1.52% and 1.04%, respectively. The contamination degree of all vegetables was clean, and there was no significant health risk by ingesting As, Cd, Pb and Hg from one single type of vegetables. The health risks of heavy metals in all kinds of vegetables were higher in children as well as in middle-aged and elderly people than in young adults. Heavy metals in stem vegetables posed a greater health risk to children, and the health risks were mainly caused by As. The contents of As, Cd, Pb and Hg in vegetables in Zibo City showed the significantly positive correlations, indicating the similarity of their sources. Conclusion The contamination of heavy metals in vegetables in Zibo City is at a relatively safe level. Heavy metals in stem vegetables should be paid more attention to the health risk of children.