Gold and Uranium

Pulford, I. D.

doi:10.1002/9781444319477.ch23

Cited by 4 publications

(9 citation statements)

References 67 publications

(81 reference statements)

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“…The U pollution, however, did not influence the mineral horizons Bw and Cr, where U concentrations correspond with natural levels [2,3]. Furthermore, the area is polluted by Pb, which is the result of long-term smelting operations in the vicinity [34].…”

Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 86%

“…Cambic Leptosols are oxidomorphic soils. The low pH values in the soil profile would suggest that U is present as U(VI) with UO 2+ as a major ion [3]. However, in organic-rich horizons, interactions of U with organic matter are expected and organic compounds (e.g., the humic acid) greatly influence the mobility and chemistry of U [5,6].…”

Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 97%

“…When considering the total concentrations and mobility of the investigated metals (Tables 1-3), Pb should be considered the most bioavailable element followed by U, Th and Ag, respectively. At the sites near Kladská and Chmelná, where EM tips were collected, the U concentrations in soils correspond to background levels [2,3] and both sites can therefore be considered unpolluted (Supplementary Tables S2 and S3). …”

Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 99%

“…Environmental contamination by U may be caused by various processes including mining and processing operations, coal combustion, testing and use of weapons with depleted uranium (DU). Artificially elevated concentrations of U in topsoils usually reach tens or a few hundred mg/kg [3], but natural accumulation in soils can on rare occasions reach 4000 mg/kg [4]. Under the conditions found in the natural environment, the two important oxidation states are U(IV) and U(VI); the chemistry of U(VI) is dominant in most soils [3].…”

Section: Introductionmentioning

confidence: 99%

“…Artificially elevated concentrations of U in topsoils usually reach tens or a few hundred mg/kg [3], but natural accumulation in soils can on rare occasions reach 4000 mg/kg [4]. Under the conditions found in the natural environment, the two important oxidation states are U(IV) and U(VI); the chemistry of U(VI) is dominant in most soils [3]. Furthermore, organic compounds influence the mobility and chemistry of U in the environment [5,6].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

Kubrová

Žigová

Řanda

et al. 2014

Journal of Hazardous Materials

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Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 86%

Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 97%

Section: Distribution and Mobility Of Metals In Soilsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

Kubrová

Žigová

Řanda

et al. 2014

Journal of Hazardous Materials

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Uranium

Alloway

2012

Environmental Pollution

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Tetra- and Hexavalent Uranium Forms Bidentate-Mononuclear Complexes with Particulate Organic Matter in a Naturally Uranium-Enriched Peatland

Mikutta

Langner

Bargar

et al. 2016

Environ. Sci. Technol.

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Peatlands frequently serve as efficient biogeochemical traps for U. Mechanisms of U immobilization in these organic matter-dominated environments may encompass the precipitation of U-bearing mineral(oid)s and the complexation of U by a vast range of (in)organic surfaces. The objective of this work was to investigate the spatial distribution and molecular binding mechanisms of U in soils of an alpine minerotrophic peatland (pH 4.7-6.6, E = -127 to 463 mV) using microfocused X-ray fluorescence spectrometry and bulk and microfocused U L-edge X-ray absorption spectroscopy. The soils contained 2.3-47.4 wt % organic C, 4.1-58.6 g/kg Fe, and up to 335 mg/kg geogenic U. Uranium was found to be heterogeneously distributed at the micrometer scale and enriched as both U(IV) and U(VI) on fibrous and woody plant debris (48 ± 10% U(IV), x̅ ± σ, n = 22). Bulk U X-ray absorption near edge structure (XANES) spectroscopy revealed that in all samples U(IV) comprised 35-68% of total U (x̅ = 50%, n = 15). Shell-fit analyses of bulk U L-edge extended X-ray absorption fine structure (EXAFS) spectra showed that U was coordinated to 1.3 ± 0.2 C atoms at a distance of 2.91 ± 0.01 Å (x̅ ± σ), which implies the formation of bidentate-mononuclear U(IV/VI) complexes with carboxyl groups. We neither found evidence for U shells at ∼3.9 Å, indicative of mineral-associated U or multinuclear U(IV) species, nor for a substantial P/Fe coordination of U. Our data indicates that U(IV/VI) complexation by natural organic matter prevents the precipitation of U minerals as well as U complexation by Fe/Mn phases at our field site, and suggests that organically complexed U(IV) is formed via reduction of organic matter-bound U(VI).

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Gold and Uranium

Cited by 4 publications

References 67 publications

On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

Uranium

Tetra- and Hexavalent Uranium Forms Bidentate-Mononuclear Complexes with Particulate Organic Matter in a Naturally Uranium-Enriched Peatland

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