Phytoremediation of Lead-Contaminated Soils: Role of Synthetic Chelates in Lead Phytoextraction

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• 作者：Jianwei W. Huang ; Jianjun Chen ; William R. Berti ; and Scott D. Cunningham
• 刊名：Environmental Science & Technology
• 出版年：1997
• 出版时间：March 1997
• 年：1997
• 卷：31
• 期：3
• 页码：800 - 805
• 全文大小：236K
• 年卷期：v.31,no.3(March 1997)
• ISSN：1520-5851

文摘

Lead phytoextraction, using plants to extract Pb fromcontaminated soils, is an emerging technology.Calculationsof soil Pb mass balance suggest that this technology willbe economically feasible only if systems can bedeveloped to employ high biomass plants that canaccumulategreater than 1% Pb in their shoots. In this study,weinvestigated the potential of adding chelates to Pb-contaminated soils to increase Pb accumulation in plants.The addition of chelates to a Pb-contaminated soil(totalsoil Pb 2500 mg kg^-1) increased shoot Pbconcentrations ofcorn (Zea mays L. cv. Fiesta) and pea (Pisumsativum L.cv. Sparkle) from less than 500 mg kg^-1 tomore than 10000mg kg^-1. The surge of Pb accumulation inthese plantswas associated with the surge of Pb level in the soilsolutiondue to the addition of chelates to the soil. For thechelatestested, the order of the effectiveness in increasing Pbdesorption from the soil was EDTA > HEDTA > DTPA >EGTA >EDDHA. We also found that EDTA significantlyincreased Pb translocation from roots to shoots. Within24h after applying EDTA solution [1.0 g of EDTA (kgsoil)^-1]to the contaminated soil, Pb concentration in the cornxylem sap increased 140-fold, and net Pb translocationfromroots to shoots increased 120-fold as compared to thecontrol (no EDTA). These results indicate thatchelatesenhanced Pb desorption from soil to soil solution,facilitatedPb transport into the xylem, and increased Pbtranslocationfrom roots to shoots. Results from this study suggestthatwith careful management, chelate-assisted Pb phytoextraction may provide a cost-effective soil decontaminationstrategy.