Uranium immobilization in an iron-rich rhizosphere of a native wetland plant from the savannah river site under reducing conditions

Hyun Shik Chang, Shea W. Buettner, John C. Seaman, Peter R. Jaffe, Paul G. Koster Van Groos, Dien Li, Aaron D. Peacock, Kirk G. Scheckel, Daniel I. Kaplan

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24 Scopus citations

Abstract

The hypothesis of this study was that iron plaques formed on the roots of wetland plants and their rhizospheres create environmental conditions favorable for iron reducing bacteria that promote the in situ immobilization of uranium. Greenhouse microcosm studies were conducted using native plants (Sparganium americanum) from a wetland located on the Savannah River Site, Aiken, SC. After iron plaques were established during a 73-day period by using an anoxic Fe(II)-rich nutrient solution, a U(VI) amended nutrient solution was added to the system for an additional two months. Compared to plant-free control microcosms, microcosms containing iron plaques successfully stimulated the growth of targeted iron reducing bacteria, Geobacter spp. Their population continuously increased after the introduction of the U(VI) nutrient solution. The reduction of some of the U(VI) to U(IV) by iron reducing bacteria was deduced based on the observations that the aqueous Fe(II) concentrations increased while the U(VI) concentrations decreased. The Fe(II) produced by the iron reducing bacteria was assumed to be reoxidized by the oxygen released from the roots. Advanced spectroscopic analyses revealed that a significant fraction of the U(VI) had been reduced to U(IV) and they were commonly deposited in association with phosphorus on the iron plaque.

Original languageEnglish (US)
Pages (from-to)9270-9278
Number of pages9
JournalEnvironmental Science and Technology
Volume48
Issue number16
DOIs
StatePublished - Aug 19 2014

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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    Chang, H. S., Buettner, S. W., Seaman, J. C., Jaffe, P. R., Koster Van Groos, P. G., Li, D., Peacock, A. D., Scheckel, K. G., & Kaplan, D. I. (2014). Uranium immobilization in an iron-rich rhizosphere of a native wetland plant from the savannah river site under reducing conditions. Environmental Science and Technology, 48(16), 9270-9278. https://doi.org/10.1021/es5015136