School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK,
Environ Sci Pollut Res Int. 2013 Dec;20(12):8955-63. doi: 10.1007/s11356-013-1883-7. Epub 2013 Jun 9.
Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (p<0.05) decreased the shoot dry matter of M. sativa by 55 % and, as such, decreased the Cr removal potential from the soil. The soluble Cr concentration in single Cr or Cr + B[a]P-contaminated soil was enhanced with the amendment of all chelates; however, only the application of citric acid in Cr-contaminated soil (44 %) or EDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.
多环芳烃和重金属是环境关注的问题，需要将它们去除到可接受的水平。植物修复，即利用植物来处理污染土壤，可能是一种替代传统修复过程的有趣方法。本工作评估了螯合剂的单一和组合应用对单一或混合 Cr + 苯并[a]芘（B[a]P）污染土壤的作用。在污染土壤中种植了 Medicago sativa，并在 60 天内用 0.3 g 柠檬酸、0.146 g 乙二胺四乙酸（EDTA）或它们的混合物进行了处理。结果表明，在 Cr 污染土壤中，EDTA + 柠檬酸的应用显著（p<0.05）降低了 M. sativa 的地上干物质 55%，从而降低了从土壤中去除 Cr 的潜力。在单一 Cr 或 Cr + B[a]P 污染土壤中，所有螯合剂的添加均提高了可溶性 Cr 浓度；然而，只有在 Cr 污染土壤中添加柠檬酸（44%）或在共污染土壤中添加 EDTA 和 EDTA + 柠檬酸才能增加 Cr 的去除（分别为 34%和 54%）。单一 B[a]P 污染土壤中 B[a]P 的消解即使在没有种植和螯合剂添加的情况下也是有效的，而在共污染土壤中，它与 EDTA 或 EDTA + 柠檬酸的应用有关。这表明，在单一或共污染土壤中，在螯合剂的帮助下，M. sativa 可以有效地用于 Cr 的植物提取，并促进 B[a]P 的生物降解。
