HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Neilson, J. W. Articles by Maier, R. M. Search for Related Content PubMed PubMed Citation Articles by Neilson, J. W. Articles by Maier, R. M. GeoRef GeoRef Citation Agricola Articles by Neilson, J. W. Articles by Maier, R. M. Related Collections Remediation Bioremediation and Biodegradation Heavy Metals Soil Pollution

TECHNICAL REPORTS
Heavy Metals in the Environment

Characterization of Lead Removal from Contaminated Soils by Nontoxic Soil-Washing Agents

Department of Soil, Water, and Environmental Science, Shantz Building, Room 429, Univ. of Arizona, Tucson, AZ 85721

^* Corresponding author (rmaier{at}ag.arizona.edu)

Received for publication May 3, 2002. Few effective strategies exist for remediating and restoring metal-contaminated soils. We have evaluated the potential of two environmentally compatible, nondestructive, biological soil-washing agents for remediating aged, lead-contaminated soils. Two contaminated soils were washed with 10 mM rhamnolipid biosurfactant and 5.3% carboxymethyl-ß-cyclodextrin (CMCD). The metal removal efficiency of these agents was compared with 10 mM diethylenetriamine pentaacetic acid (DTPA) and 10 mM KNO₃. Lead removal rates by both soil-washing agents exceeded the removal by KNO₃, but were an order of magnitude less than removal by the synthetic chelator, DTPA. Analysis of soil extractions revealed that the Pb in the first soil (3780 mg kg^-1) was primarily associated with the soluble, exchangeable, oxide, and residual fractions while the Pb in the second soil (23 900 mg kg^-1) was found in the soluble, exchangeable, carbonate, and residual fractions. After 10 consecutive washes, rhamnolipid had removed 14.2 and 15.3% of the Pb from the first and second soils, respectively, and CMCD had removed 5 and 13.4% from the same two soils. The Pb removal rate by both agents either increased or was consistent throughout the 10 extractions, indicating a potential for continued removal with extended washing. Significant levels of Cu and Zn in both soils did not prevent Pb removal by either agent. Interestingly, the effectiveness of each agent varied as a function of Pb speciation in the soil. Rhamnolipid was more effective than CMCD in removing Pb bound to amorphous iron oxides, while both agents demonstrated similar potential for removing soluble, exchangeable, and carbonate-bound Pb. Neither agent demonstrated potential for the complete remediation of metal-contaminated soils.

Abbreviations: CMCD, carboxymethyl-ß-cyclodextrin • DTPA, diethylenetriamine pentaacetic acid • EDTA, ethylenediamine tetraacetic acid • TCLP, toxicity characteristic leaching procedure

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2003 32: 745-750. [Full Text]  

This article has been cited by other articles:

				J. C. Seaman, V. M. Vulava, A. G. Sowder, B. P. Jackson, S. A. Aburime, and P. M. Bertsch Metal extractability from contaminated SRS sediments: Comparison of column and batch results Environmental Geosciences, December 1, 2005; 12(4): 235 - 242. [Abstract] [Full Text] [PDF]