Evaluation of Rapidly Biodegradable Chelating Agents for Lead and Uranium Phytoextraction. (S11-elless440873-oral)
Authors:
M.P. Elless* - Edenspace Systems Corp.
R. Parra - New Mexico State Univ.
A.L. Ulery - New Mexico State Univ.
V. Anne - New Mexico State Univ.
Abstract:
Lead and U contaminants in soils are usually insoluble. In order to optimize phytoremediation of contaminated soils, chelates are often added to enhance extraction of metals by plants. The most proficient chelating agent for Pb is ethylenediamine tetraacetic acid (EDTA). The Pb-EDTA complex is mobile and stable in most soils, due to its slow degradation, and is thus prone to leach through soils and threaten the quality of shallow ground waters. Other organic acids may break down more quickly but still provide enhanced phytoextractibility. We measured the degradation rates of several chelating agents for Pb and U by leaching columns containing contaminated soil over 28 days and analyzing the leachate for metals. Citric acid extracted more U than 12 other chelates tested in a batch study. The citrate complexes had the fastest degradation rates and extracted the most U, but much less Pb than other chelates. EDTA extracted the most Pb, and less U, but continued to leach Pb up to at least 20 d after application. Nitriloacetic acid solubilized up to 50% of the Pb that EDTA extracted but degraded within 20 d so may be a suitable alternative for Pb phytoextraction enhancement.
Speaker Information: Mark Elless, Edenspace Systems Corp., 15100 Enterprise Court Suite 100, Dulles, VA 20151; Phone: 703-961-8700; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 1421)
Keywords: phytoextraction; chelating agents; lead; uranium