School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
Dongjiang Environmental Company Limited, Dongjiang Environmental Building, No. 9, Langshan Road, North Area, High-tech Industrial Park, Nanshan District, Shenzhen City, Guangdong, 518057, China.
Environ Sci Pollut Res Int. 2017 Nov;24(31):24409-24418. doi: 10.1007/s11356-017-0065-4. Epub 2017 Sep 11.
Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays, applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R-square (R ) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg soil, pH 4.5), and rhamnolipid (pH 6.5).
螯合剂强化植物提取法已被提出作为一种有效的土壤修复方法，但重金属浸出问题不容忽视。本研究采用土柱作物浸出实验，应用玉米幼苗，使用三种不同螯合剂（EDTA、EDDS 和鼠李糖脂）和人工降雨（酸雨或正常降雨），研究了辅助提取 Cd 和 Pb 污染土壤过程中重金属浸出变化。结果表明，螯合剂施用后的人工降雨，特别是人工酸雨，导致浸出溶液中重金属含量增加。EDTA 明显增加了浸出溶液中 Cd 和 Pb 的浓度，而 EDDS 和鼠李糖脂增加了 Cd 浓度但没有增加 Pb 浓度。随着浸出溶液的增加，Cd 和 Pb 的含量减少，模式与 LRM（线性回归模型）相匹配，Cd 和 Pb 的 R 平方（R）分别高于 90%和 82%。在 EDTA 和酸雨（pH 4.5）处理下，浸出溶液中最大累积 Cd 和 Pb 分别为 18.44%和 16.68%，其次是 EDDS（pH 4.5）、EDDS（pH 6.5）、鼠李糖脂（0.5 g kg 土壤，pH 4.5）和鼠李糖脂（pH 6.5）。
