Zhao Shulan, Jia Lina, Duo Lian
J Environ Qual. 2016 May;45(3):933-9. doi: 10.2134/jeq2016.01.0020.
Phytoextraction has the potential to remove heavy metals from contaminated soil, and chelants can be used to improve the capabilities of phytoextraction. However, environmentally persistent chelants can cause metal leaching and groundwater pollution. A column experiment was conducted to evaluate the viability of biodegradable nitrilotriacetic acid (NTA) to increase the uptake of heavy metals (Cd, Cr, Ni, Pb, Cu, and Zn) by L. in municipal solid waste (MSW) compost and to evaluate the effect of two permeable barrier materials, bone meal and crab shell, on metal leaching. The application of NTA significantly increased the concentrations and uptake of heavy metals in . The enhancement was more pronounced at higher dosages of NTA. In the 15 mmol kg NTA treatment using a crab shell barrier, the Cr and Ni concentrations in the plant shoots increased by approximately 8- and 10-fold, respectively, relative to the control. However, the addition of NTA also caused significant heavy metal leaching from the MSW compost. Bone meal and crab shell barriers positioned between the compost and the subsoil were effective in preventing metal leaching down through the soil profile by the retention of metals in the barrier. The application of a biodegradable chelant and the use of permeable barriers is a viable form of enhanced phytoextraction to increase the removal of metals and to reduce possible leaching.
植物提取技术有潜力从受污染土壤中去除重金属，螯合剂可用于提高植物提取能力。然而，环境持久性螯合剂会导致金属淋溶和地下水污染。开展了一项柱实验，以评估可生物降解的氮川三乙酸（NTA）提高城市固体废物（MSW）堆肥中李氏禾对重金属（镉、铬、镍、铅、铜和锌）吸收的可行性，并评估两种渗透屏障材料骨粉和蟹壳对金属淋溶的影响。NTA的施用显著提高了李氏禾中重金属的浓度和吸收量。在较高剂量的NTA下，这种增强作用更为明显。在使用蟹壳屏障的15 mmol·kg NTA处理中，与对照相比，植物地上部分的铬和镍浓度分别增加了约8倍和10倍。然而，添加NTA也导致城市固体废物堆肥中大量重金属淋溶。置于堆肥和底土之间的骨粉和蟹壳屏障通过在屏障中保留金属，有效地防止了金属通过土壤剖面向下淋溶。施用可生物降解螯合剂和使用渗透屏障是一种可行的强化植物提取形式，可增加金属去除量并减少可能的淋溶。
