Pollution effects of atmospheric deposition on heavy metals in leafy vegetables and its health risks
2018, 2018 (2):
In order to study the pollution effects of heavy metals in atmospheric deposition on leafy vegetables and health risks via consuming vegetables, this research chooses a farmland near the suburban Shanghai as a study area, makes comparative analysis of heavy metal contents in vegetables samples, including Shanghai Green cabbage, leaf lettuce, amaranth and water spinach, both in outdoor and greenhouses, and makes the health risk assessment of the edible parts of vegetables using the target hazard quotient (THQ). The results show that the heavy metal contents of the vegetables in outdoor are higher than those in greenhouses. The average contents of Zn, Cr, Cu, Pb, Cd, Hg, and As in outdoor vegetables are 7.32, 0.91, 0.52, 0.007, 0.029, 0.002, and 0.014 mg·kg-1, respectively; among which, the contents of Zn, Cr, Cu, Cd, and Hg are 26.4%, 28.4%, 83.3%, 33.9%, and 14% higher than those in greenhouses, respectively. The enrichment factors of greenhouse vegetables are higher than those of outdoor vegetables, showing that the heavy metals of outdoor vegetables are greatly influenced by atmospheric deposition. Different vegetables have different enrichment capacity of heavy metals. Amaranth has the strongest enrichment capacity for Zn, Hg, As and Cu; while water spinach has the most powerful enrichment capacity for Pb. TotalTarget Hazard Quotient (TTHQ)values ofvegetables in outdoor are between 1.41 to 2.99 with an average of 2.29; while those in greenhouses are between 1.10 to 2.19 with an average of 1.85, which is 23.4% lower than the outdoor values. There is a threat for the health of adult and children. The risk of consuming vegetables in outdoor is higher than that in greenhouses. Atmospheric deposition is one of the important sources of heavy metals in vegetables. Hence, we suggest to avoid outdoor cultivating vegetables in high risk areas with atmospheric pollution of heavy metals, thus reducing the impact of atmospheric deposition on enrichment of heavy metals in vegetables.
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