Uranium fate in wetland mesocosms: Effects of plants at two iron loadings with different pH values

Paul G. Koster van Groos, Daniel I. Kaplan, Hyun shik Chang, John C. Seaman, Dien Li, Aaron D. Peacock, Kirk G. Scheckel, Peter R. Jaffe

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Small-scale continuous flow wetland mesocosms (∼0.8 L) were used to evaluate how plant roots under different iron loadings affect uranium (U) mobility. When significant concentrations of ferrous iron (Fe) were present at circumneutral pH values, U concentrations in root exposed sediments were an order of magnitude greater than concentrations in root excluded sediments. Micro X-ray absorption near-edge structure (μ-XANES) spectroscopy indicated that U was associated with the plant roots primarily as U(VI) or U(V), with limited evidence of U(IV). Micro X-ray fluorescence (μ-XRF) of plant roots suggested that for high iron loading at circumneutral pH, U was co-located with Fe, perhaps co-precipitated with root Fe plaques, while for low iron loading at a pH of ∼4 the correlation between U and Fe was not significant, consistent with previous observations of U associated with organic matter. Quantitative PCR analyses indicated that the root exposed sediments also contained elevated numbers of Geobacter spp., which are likely associated with enhanced iron cycling, but may also reduce mobile U(VI) to less mobile U(IV) species.

Original languageEnglish (US)
Pages (from-to)116-124
Number of pages9
JournalChemosphere
Volume163
DOIs
StatePublished - Nov 1 2016

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

Keywords

  • Iron
  • Plants
  • Rhizosphere
  • Uranium fate
  • Uranium sequestration
  • Wetlands

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  • Cite this

    Koster van Groos, P. G., Kaplan, D. I., Chang, H. S., Seaman, J. C., Li, D., Peacock, A. D., Scheckel, K. G., & Jaffe, P. R. (2016). Uranium fate in wetland mesocosms: Effects of plants at two iron loadings with different pH values. Chemosphere, 163, 116-124. https://doi.org/10.1016/j.chemosphere.2016.08.012