EDDS与EDTA强化苎麻修复镉铅污染土壤

为探明施用生物可降解螯合剂乙二胺二琥珀酸(EDDS)对苎麻修复重金属污染土壤的效果,通过盆栽试验研究了镉、铅复合污染黄褐土中施加EDTA和EDDS对苎麻生物量、叶片中丙二醛含量及重金属镉、铅积累特性的影响。结果表明:相比单一种植苎麻,施加EDTA和EDDS都能显著增强苎麻植株各部位铅、镉的含量,提升苎麻对土壤中重金属的修复效果。在浓度为1.5～3 mmol·kg^-1时,EDDS强化苎麻修复镉的效果较好,土壤镉的去除效率相比对照提高了16%～27%,在更高浓度时,EDTA强化苎麻修复镉的效果较好;EDTA强化苎麻修复土壤铅的效果好于EDDS,对土壤铅的去除效果可提高达22.6%。但EDTA和EDDS的施加会造成苎麻生物量减少,叶片丙二醛含量增加,在同等浓度水平下,EDDS对苎麻生长产生的不利影响要小于EDTA。

EDTA and EDDS Enhanced Remediation of Cd and Pb Contaminated Soil by Ramie(Boehmeria Nivea)

Ramie(Boehmeria nivea) has showed potential to remediate heavy metal contaminated soils. However, low availability of heavy metals in soils limits the remediation efficiencies. Here a pot experiment was conducted to assess the effects of two chelating agents, ethylene diamine disuccinate(EDDS) and ethylene diamine tetraacetate(EDTA), on the uptake of Cd and Pb by ramie in Cd and Pb contaminated yellow-cinnamon soil. Biomass and malondialdehyde(MDA) content of ramie and concentrations of Cd and Pb in both different parts of ramie and soil were measured. The total content of Cd and Pb in leaf, shoot and root of ramie grown in EDTA and EDDS treated soils increased significantly, suggesting the activation of heavy metals in the soils. At 1.5 mmol·kg^-1 to 3 mmol·kg^-1 of chelating agents, EDDS performed better in Cd accumulation than EDTA did, with Cd removal being 16% to 27% greater than the control(no chelating agent). At higher than 3 mmol·kg^-1 of chelating agents, however, ramie with EDTA treatment had higher Cd concentration than that with EDDS. For Pb contaminated soil, EDTA activated Pb better than EDDS did, and the removal efficiency of Pb by ramie increased by up to 22.6%. Applications of both EDTA and EDDS reduced ramie biomass but improved the content of MDA in leaves. However, EDDS showed less adverse effects on ramie than EDTA did at the same concentrations.