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

Lead phytoextraction, using plants to extract Pb from contaminated soils, is an emerging technology. Calculations of soil Pb mass balance suggest that this technology will be economically feasible only if systems can be developed to employ high biomass plants that can accumulate greater than 1% Pb i...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 1997-03, Vol.31 (3), p.800-805
Main Authors: Huang, Jianwei W., Chen, Jianjun, Berti, William R., Cunningham, Scott D.
Format: Article
Language:English
Subjects:
Chemistry
Contamination
Flowers & plants
LEAD
PLOMB
PLOMO
POLLUTION DU SOL
POLUCION DEL SUELO
SOIL POLLUTION
Soils
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Lead phytoextraction, using plants to extract Pb from contaminated soils, is an emerging technology. Calculations of soil Pb mass balance suggest that this technology will be economically feasible only if systems can be developed to employ high biomass plants that can accumulate greater than 1% Pb in their shoots. In this study, we investigated the potential of adding chelates to Pb-contaminated soils to increase Pb accumulation in plants. The addition of chelates to a Pb-contaminated soil (total soil Pb 2500 mg kg-1) increased shoot Pb concentrations of corn (Zea mays L. cv. Fiesta) and pea (Pisum sativum L. cv. Sparkle) from less than 500 mg kg-1 to more than 10000 mg kg-1. The surge of Pb accumulation in these plants was associated with the surge of Pb level in the soil solution due to the addition of chelates to the soil. For the chelates tested, the order of the effectiveness in increasing Pb desorption from the soil was EDTA > HEDTA > DTPA > EGTA >EDDHA. We also found that EDTA significantly increased Pb translocation from roots to shoots. Within 24 h after applying EDTA solution [1.0 g of EDTA (kg soil)-1] to the contaminated soil, Pb concentration in the corn xylem sap increased 140-fold, and net Pb translocation from roots to shoots increased 120-fold as compared to the control (no EDTA). These results indicate that chelates enhanced Pb desorption from soil to soil solution, facilitated Pb transport into the xylem, and increased Pb translocation from roots to shoots. Results from this study suggest that with careful management, chelate-assisted Pb phytoextraction may provide a cost-effective soil decontamination strategy.
ISSN:0013-936X
1520-5851
DOI:10.1021/es9604828