Vadose-zone alteration of metaschoepite and ceramic UO2 in Savannah River Site field lysimeters

Connaugh M. Fallon; William R. Bower; Brian A. Powell; Francis R. Livens; Ian C. Lyon; Alana E. McNulty; Kathryn Peruski; J. Frederick W. Mosselmans; Daniel I. Kaplan; Daniel Grolimund; Peter Warnicke; Dario Ferreira-Sanchez; Marja Siitari Kauppi; Gianni F. Vettese; Samuel Shaw; Katherine Morris; Gareth T.W. Law

doi:10.1016/j.scitotenv.2022.160862

Vadose-zone alteration of metaschoepite and ceramic UO₂ in Savannah River Site field lysimeters

Connaugh M. Fallon, William R. Bower, Brian A. Powell, Francis R. Livens, Ian C. Lyon, Alana E. McNulty, Kathryn Peruski, J. Frederick W. Mosselmans, Daniel I. Kaplan, Daniel Grolimund, Peter Warnicke, Dario Ferreira-Sanchez, Marja Siitari Kauppi, Gianni F. Vettese, Samuel Shaw, Katherine Morris, Gareth T.W. Law

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Uranium dioxide (UO₂) and metaschoepite (UO₃•nH₂O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO₂ lysimeter, oxidative dissolution of UO₂ and subsequent migration of U was observed over 1–2 cm in the direction of waterflow and against it. Sequential extractions of the UO₂ sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.

Original language	English
Article number	160862
Journal	Science of the Total Environment
Volume	862
DOIs	https://doi.org/10.1016/j.scitotenv.2022.160862
State	Published - Mar 1 2023
Externally published	Yes

Funding

This work was supported by a PhD bursary to CMF from AWE and the UK EPSRC Next Generation Nuclear Centre for Doctoral Training (EP/L015390/1). GL, FRL, ICL, and KM acknowledge funding from UK NERC grants NE/M014088/1 and NE/L000202/1. NE/L000202/1 is the NERC RATE programme which was co-funded by the UK Environment Agency and Radioactive Waste Management Ltd. GL also acknowledges funding from the Finnish KYT2022 programme. BP acknowledges support from the U.S. Department of Energy Office of Science (DOE-OS), Office of Basic Energy Sciences, and Office of Biological and Environmental Research under Award Number DE-SC-0012530. DK acknowledges DOE-OS funding from the Environmental Systems Science Program (DE-AC02-06CH11357) and DOE-Environmental Management funding through a Cooperative Agreement (DE-EM0005228) with The University of Georgia Research Foundation. We thank University of Manchester staff members Steve Stockley, Alistair Bewsher, Paul Lythgoe, and Dr. Heath Bagshaw, and University of Helsinki staff member Dr. Katie Doig for technical assistance and advice. Diamond Light Source and the Swiss Light Source are thanked for beamtimes SP 16611, SP16939, SP17243 and 20181008. This work was supported by a PhD bursary to CMF from AWE and the UK EPSRC Next Generation Nuclear Centre for Doctoral Training (EP/L015390/1). GL, FRL, ICL, and KM acknowledge funding from UK NERC grants NE/M014088/1 and NE/L000202/1 . NE/L000202/1 is the NERC RATE programme which was co-funded by the UK Environment Agency and Radioactive Waste Management Ltd . GL also acknowledges funding from the Finnish KYT2022 programme. BP acknowledges support from the U.S. Department of Energy Office of Science (DOE-OS) , Office of Basic Energy Sciences , and Office of Biological and Environmental Research under Award Number DE-SC-0012530 . DK acknowledges DOE-OS funding from the Environmental Systems Science Program ( DE-AC02-06CH11357 ) and DOE-Environmental Management funding through a Cooperative Agreement ( DE-EM0005228 ) with The University of Georgia Research Foundation. We thank University of Manchester staff members Steve Stockley, Alistair Bewsher, Paul Lythgoe, and Dr. Heath Bagshaw, and University of Helsinki staff member Dr. Katie Doig for technical assistance and advice. Diamond Light Source and the Swiss Light Source are thanked for beamtimes SP 16611, SP16939, SP17243 and 20181008.

Keywords

Groundwater
Speciation
Surface water
Uranium
X-ray absorption spectroscopy

Access to Document

10.1016/j.scitotenv.2022.160862

Cite this

Fallon, C. M., Bower, W. R., Powell, B. A., Livens, F. R., Lyon, I. C., McNulty, A. E., Peruski, K., Mosselmans, J. F. W., Kaplan, D. I., Grolimund, D., Warnicke, P., Ferreira-Sanchez, D., Kauppi, M. S., Vettese, G. F., Shaw, S., Morris, K., & Law, G. T. W. (2023). Vadose-zone alteration of metaschoepite and ceramic UO₂ in Savannah River Site field lysimeters. Science of the Total Environment, 862, Article 160862. https://doi.org/10.1016/j.scitotenv.2022.160862

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abstract = "Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1–2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.",

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author = "Fallon, {Connaugh M.} and Bower, {William R.} and Powell, {Brian A.} and Livens, {Francis R.} and Lyon, {Ian C.} and McNulty, {Alana E.} and Kathryn Peruski and Mosselmans, {J. Frederick W.} and Kaplan, {Daniel I.} and Daniel Grolimund and Peter Warnicke and Dario Ferreira-Sanchez and Kauppi, {Marja Siitari} and Vettese, {Gianni F.} and Samuel Shaw and Katherine Morris and Law, {Gareth T.W.}",

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Fallon, CM, Bower, WR, Powell, BA, Livens, FR, Lyon, IC, McNulty, AE, Peruski, K, Mosselmans, JFW, Kaplan, DI, Grolimund, D, Warnicke, P, Ferreira-Sanchez, D, Kauppi, MS, Vettese, GF, Shaw, S, Morris, K & Law, GTW 2023, 'Vadose-zone alteration of metaschoepite and ceramic UO₂ in Savannah River Site field lysimeters', Science of the Total Environment, vol. 862, 160862. https://doi.org/10.1016/j.scitotenv.2022.160862

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T1 - Vadose-zone alteration of metaschoepite and ceramic UO2 in Savannah River Site field lysimeters

AU - Fallon, Connaugh M.

AU - Bower, William R.

AU - Powell, Brian A.

AU - Livens, Francis R.

AU - Lyon, Ian C.

AU - McNulty, Alana E.

AU - Peruski, Kathryn

AU - Mosselmans, J. Frederick W.

AU - Kaplan, Daniel I.

AU - Grolimund, Daniel

AU - Warnicke, Peter

AU - Ferreira-Sanchez, Dario

AU - Kauppi, Marja Siitari

AU - Vettese, Gianni F.

AU - Shaw, Samuel

AU - Morris, Katherine

AU - Law, Gareth T.W.

PY - 2023/3/1

Y1 - 2023/3/1

N2 - Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1–2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.

AB - Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1–2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.

KW - Groundwater

KW - Speciation

KW - Surface water

KW - Uranium

KW - X-ray absorption spectroscopy

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