Chelate-Assisted Pb Phytoextraction:  Pb Availability, Uptake, and Translocation Constraints

Wu, Jianjun; Hsu, Francis C.; Cunningham, Scott D.

doi:10.1021/es9809253

Cited by 214 publications

(152 citation statements)

References 22 publications

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“…These chelating agents included EDTA (Wu et al, 1999;Lombi et al, 2001), EDDS (log Ks = 18.4, Tandy et al, 2004), EGTA (Römkens et al, 2002), HBED (Wu et al, 1999), and NTA (Kulli et al, 1999;Kayser et al, 2000). However, the chelateenhanced Cu uptake by plant shoots was generally minimal (Kulli et al, 1999;Wu et al, 1999;Kayser et al, 2000;Lombi et al, 2001;Römkens et al, 2002) except for the result reported by Blaylock et al (1997). In that study, a 2.5 mmol kg -1 EDTA treatment to the soil increased the concentration of Cu to 1000 mg kg -1 DW in B. juncea shoots.…”

Section: Discussionmentioning

confidence: 99%

“…When 5 mmol kg -1 of EDDS was applied, the percentage of absorbed Cu translocated from roots to shoots increased from 8.5% to 83% and from 10.2% to 93% in corn and beans, respectively. Most of the increased uptake of Pb after the chelate treatments could be explained as an effect of enhanced Pb solubility (Wu et al, 1999;Kayser et al, 2000). It was reported that the accumulation of Pb in plant shoots correlated with the formation of the Pb-EDTA complex, and that Pb-EDTA was the major form of Pb absorbed and translocated by the plant (Vassil et al, 1998;Epstein et al, 1999).…”

Section: The Effectiveness Of Edds To Stimulating the Accumulation Ofmentioning

confidence: 99%

“…Soil factors such as pH, cation exchange capacity, or organic matter content play an important role in successful soil remediation processes. To increase metal availability, a number of chelates such as EDTA (ethylenediaminetetraacetic acid), CDTA (trans -1, 2 -diaminocyclohexane -N, N, N', N'-tetraacetic acid), EGTA [ethyleneglycol -bis (ß -aminoethyl ether), N, N, N', N-tetraacetic acid], and EDDHA [etylenediamine-di (ohydroxyphenylacetic acid)]) have been used to desorb metals from the soil matrix into soil solution to facilitate the transport of metals into xylem, and increase the translocation of metals from the roots to shoots of some fast-growing, high-biomass-producing plants (Blaylock et al, 1997;Huang et al, 1997;Cooper et al, 1999;Wu et al, 1999;Shen et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS

2005

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Chemically enhanced phytoextraction has been proposed as an effective approach to removing heavy metals from contaminated soil through the use of high biomass plants.Using pot experiments, the effects of the application of EDTA, EDDS and citric acid on the uptake of Cu, Pb, Zn and Cd by corn (Zea mays L. cv. Nongda 108) and bean (Phaseolus vulgaris L. white bean) plants were studied. The results showed that EDDS was more effective than EDTA at increasing the concentration of Cu in corn and beans.The application of 5 mmol kg -1 soil EDDS application to soil significantly increased concentrations of Cu in shoots , with maximum levels of 2060 and 5130 mg kg -1 DW in corn and beans, respectively, which were 45-fold and 135-fold higher than that in the corresponding control plants to which chelate had not been applied. Concentrations of Zn in shoots were also higher in the plants treated with EDDS than in those treated with EDTA. For Pb and Cd, EDDS was less effective than EDTA. The maximum Cu This is the Pre-Published Version.2 phytoextraction was found with the EDDS treatment. The application of EDTA and EDDS also significantly increased the shoot-to-root ratios of the concentrations of Cu, Pb, Zn and Cd in both plant species. The results of metal extraction with chelates showed that EDDS was more efficient at solubilizing Cu and Zn than EDTA, and that EDTA was better at solubilizing Pb and Cd than EDDS.

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Section: Discussionmentioning

confidence: 99%

Section: The Effectiveness Of Edds To Stimulating the Accumulation Ofmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS

2005

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“…EDTA was found by Blaylock et al (1997) and Wu et al (1999) to be the most efficient in increasing water-soluble metal concentrations. Exudation of organic compounds by roots may influence ion solubility and uptake through their indirect effects on microbial activity, rhizosphere physical properties and root growth dynamics, and directly through acidification, chelation, precipitation and oxidation-reduction reactions in the rhizosphere (Uren and Reisenauer, 1988;Marschner, 1995).…”

Section: Introductionmentioning

confidence: 93%

Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil

et al. 2003

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A pot experiment was conducted to study the effects of EDTA and low molecular weight organic acids (LMWOA) on the pH, total organic carbon (TOC) and heavy metals in the soil solution in the rhizosphere of Brassica juncea grown in a paddy soil contaminated with Cu, Zn, Pb and Cd. The results show that EDTA and LMWOA have no effect on the soil solution pH. EDTA addition significantly increased the TOC concentrations in the soil solution. The TOC concentrations in treatments with EDTA were significantly higher than those in treatments with LMWOA. Adding 3 mmol kg À1 EDTA to the soil markedly increased the total concentrations of Cu, Zn, Pb and Cd in the soil solution. Compared to EDTA, LMWOA had a very small effect on the metal concentrations. Total concentrations in the soil solution followed the sequence: EDTA ) citric acid ðCAÞ % oxalic acid ðOAÞ % malic acid (MA) for Cu and Pb; EDTA ) MA ) CA % OA for Zn; and EDTA ) MA ) CA > OA for Cd. The labile concentrations of Cu, Zn, Pb and Cd showed similar trends to the total concentrations.

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“…Being one of the most frequently encountered metal contaminants in many agricultural and industrial areas, the environmental fate of Pb and its uptake by plants has been the subject of much research (Manceau et al 1996;Wu et al 1999). Because of its limited solubility due to the formation of insoluble precipitates, bioavailable levels of Pb in soils are generally low compared to other heavy metals, thus making it difficult to apply phytoremediation techniques to Pb-contaminated soils.…”

Section: Introductionmentioning

confidence: 99%

Organic acids enhance the uptake of lead by wheat roots

Wang

Shan

Liu

et al. 2006

Planta

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The uptake and bioavailability of lead (Pb) in soil-plant systems remain poorly understood. This study indicates that acetic and malic acids enhance the uptake of Pb by wheat (Triticum aestivum L.) roots under hydroponic conditions. The net concentration-dependent uptake influx of Pb in the presence and absence of organic acids was characterized by Michaelis-Menten type nonsaturating kinetic curves that could be resolved into linear and saturable components. Fitted maximum uptake rates (V max ) of the Michaelis-Menton saturable component in the presence of acetic and malic acids were, respectively, 2.45 and 1.63 times those of the control, while the Michaelis-Menten K m values of 5.5, 3.7 and 2.2 lM, respectively, remained unchanged. Enhanced Pb uptake by organic acids was partially mediated by Ca 2+ and K + channels, and also depended upon the physiological function of the plasma membrane P-type ATPase. Uptake may have been further enhanced by an effectively thinner unstirred layer of Pb adjacent to the roots, leading to more rapid diffusion towards roots. X-ray absorption spectroscopic studies provided evidence that the coordination environment of Pb in wheat roots was similar to that of Pb(CH 3 COO) 2 Á3H 2 O in that one Pb atom was coordinated to four oxygen atoms via the carboxylate group.

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Chelate-Assisted Pb Phytoextraction: Pb Availability, Uptake, and Translocation Constraints

Cited by 214 publications

References 22 publications

Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS

Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS

Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil

Organic acids enhance the uptake of lead by wheat roots

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