Dataset Information

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil.

ABSTRACT: Wetlands mitigate the migration of groundwater contaminants through a series of biogeochemical gradients that enhance multiple contaminant-binding processes. The hypothesis of this study was that wetland plant roots contribute organic carbon and release O2 within the rhizosphere (plant-impact soil zone) that promote the formation of Fe(III)-(oxyhydr)oxides. In turn, these Fe(III)-(oxyhydr)oxides stabilize organic matter that together contribute to contaminant immobilization. Mineralogy and U binding environments of the rhizosphere were evaluated in samples collected from contaminated and non-contaminated areas of a wetland on the Savannah River Site in South Carolina. Based on Mössbauer spectroscopy, rhizosphere soil was greatly enriched with nanogoethite, ferrihydrite-like nanoparticulates, and hematite, with negligible Fe(II) present. X-ray computed tomography and various microscopy techniques showed that root plaques were tens-of-microns thick and consisted of highly oriented Fe-nanoparticles, suggesting that the roots were involved in creating the biogeochemical conditions conducive to the nanoparticle formation. XAS showed that a majority of the U in the bulk wetland soil was in the +6 oxidation state and was not well correlated spatially to Fe concentrations. SEM/EDS confirm that U was enriched on root plaques, where it was always found in association with P. Together these findings support our hypothesis and suggest that plants can alter mineralogical conditions that may be conducive to contaminant immobilization in wetlands.

SUBMITTER: Kaplan DI

PROVIDER: S-EPMC7388027 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil.

Kaplan Daniel I DI Kukkadapu Ravi R Seaman John C JC Arey Bruce W BW Dohnalkova Alice C AC Buettner Shea S Li Dien D Varga Tamas T Scheckel Kirk G KG Jaffé Peter R PR

The Science of the total environment 20160618

Wetlands mitigate the migration of groundwater contaminants through a series of biogeochemical gradients that enhance multiple contaminant-binding processes. The hypothesis of this study was that wetland plant roots contribute organic carbon and release O2 within the rhizosphere (plant-impact soil zone) that promote the formation of Fe(III)-(oxyhydr)oxides. In turn, these Fe(III)-(oxyhydr)oxides stabilize organic matter that together contribute to contaminant immobilization. Mineralogy and U bin ...[more]

PMID: 27328400

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Dataset Information

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil.

Publications

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil.

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