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| Heavy metal contamination in soil-vegetable systems and its health risks in an area irrigated with acid mine drainage in Dabaoshan, Guangdong, China |
| Received:January 01, 2020 |
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| KeyWord:vegetable;heavy metal;bioaccumulation;translocation;health risk assessment |
| Author Name | Affiliation | E-mail | | CAO Chun | College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China | | | ZHANG Song | College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China | 13527333153@163.com | | ZHANG Peng | College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China | | | LIU Yu-chen | School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518000, China | | | CHEN Xun-wen | School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518000, China | | | WANG Jun-jian | School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518000, China | |
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| Abstract: |
| To study the effects of heavy metals in soil-vegetable systems and their health risks via the consumption of contaminated vegetables in an area irrigated with acid mine wastewater, the study sampled eight vegetables and their rhizosphere soils in polluted farmlands in Dabaoshan, Guangdong Province. Belowground bioconcentration factor and translocation factor were calculated to analyze the absorption and translocation of Cu, Zn, Cr, As, Pb, and Cd in vegetables. Estimated daily intake of heavy metals via vegetable consumption and target hazard quotient(THQ)were used for health risk assessment. The results showed that 94.9% of the soil samples exceeded the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land(GB 15618-2018)for Cu, 89.5% for Cd, 84.6% for Pb, 69.2% for As, 10.5% for Cr, and 10.3% for Zn. The concentrations of the six metals in the aboveground tissues exceeded Health Standard for Zinc in Food(GB 13106-1991),Health Standard for Copper in Food(GB 15199-1994)and Maximum Allowable Concentration in Food(GB 2762-2017)for vegetables, among them Cr, Pb, and Cd exceeded the standards significantly. Furthermore, the accumulation of heavy metals was the highest in Ipomoea aquatica Forssk, Brassica chinensis L., and Solanum melongena L. among all the studied vegetables. The results showed that the belowground part of vegetables had a relatively strong ability to enrich Cr and Cd. Although the soil Cr pollution was not serious, there was a risk of co-pollution of Cd and Cr in vegetables. Cd exhibited a stronger migration ability from the belowground part to aboveground part of vegetables than the other metals. The health-risk assessment showed that the average THQ decreased in the following order:THQAs > THQCr > THQCd > THQPb > THQCu > THQZn; As, Cr, and Cd contributed more than 87% to the total THQ. Moreover, the health risks of consuming heavy metal-contaminated vegetables were higher in children than in adults. Our results suggest that there is serious heavy metal pollution in local farmlands irrigated with wastewater, and that I. aquatica, Brassica campestris, and S. melongena can cause the highest human health risk among the vegetables. Thus, the consumption of alternative vegetables with lower metal accumulation is recommended. |
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