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Title

Colloidal Size and Redox State of Uranium Species in the Porewater of a Pristine Mountain Wetland

Authors
Dublet, Gabrielle
Frutschi, Manon
Brown, Ashley
Zünd, Giada C.
Bartova, Barbora
Bernier-Latmani, Rizlan
Published in Environmental Science & Technology. 2019, vol. 53, no. 16, p. 9361-9369
Abstract Uranium (U) speciation was investigated in anoxically preserved porewater samples of a natural mountain wetland in Gola di Lago, Ticino, Switzerland. U porewater concentrations ranged from less than 1 μg/L to tens of μg/L, challenging the available analytical approaches for U speciation in natural samples. Asymmetrical flow field-flow fractionation coupled with inductively coupled plasma mass spectrometry allowed the characterization of colloid populations and the determination of the size distribution of U species in the porewater. Most of the U was associated with three fractions: <0.3 kDa, likely including dissolved U and very small U colloids; a 1–3 kDa fraction containing humic-like organic compounds, dispersed Fe, and, to a small extent, Fe nanoparticles; and a third fraction (5–50 nm), containing a higher amount of Fe and a lower amount of organic matter and U relative to the 1–3 kDa fraction. The proportion of U associated with the 1–3 kDa colloids varied spatially and seasonally. Using anion exchange resins, we also found that a significant proportion of U occurs in its reduced form, U(IV). Tetravalent U was interpreted as occurring within the colloidal pool of U. This study suggests that U(IV) can occur as small (1–3 kDa), organic-rich, and thus potentially mobile colloidal species in naturally reducing wetland environments.
Keywords Flow field-flow fractionation coupled with inductively coupled plasma mass spectrometryColloids
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Other version: http://pubs.acs.org/doi/10.1021/acs.est.9b01417
Structures
Research groups Environmental Biogeochemistry and Ecotoxicology
ISE Eau
ISE Pôle Sciences
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(ISO format)
DUBLET, Gabrielle et al. Colloidal Size and Redox State of Uranium Species in the Porewater of a Pristine Mountain Wetland. In: Environmental Science & Technology, 2019, vol. 53, n° 16, p. 9361-9369. doi: 10.1021/acs.est.9b01417 https://archive-ouverte.unige.ch/unige:122744

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Deposited on : 2019-09-06

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