气候变化领域集成服务门户(CCPortal): Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years

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DOI	10.1073/pnas.2021844118
	Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years
	Lefebvre P.; Gourgiotis A.; Mangeret A.; Sabatier P.; Le Pape P.; Diez O.; Louvat P.; Menguy N.; Merrot P.; Baya C.; Zebracki M.; Blanchart P.; Malet E.; Jézéquel D.; Reyss J.-L.; Bargar J.R.; Gaillardet J.; Cazala C.; Morin G.
发表日期	2021
ISSN	00278424
卷号	118 期号:4
英文摘要	The long-term fate of uranium-contaminated sediments, especially downstream former mining areas, is a widespread environmental challenge. Essential for their management is the proper understanding of uranium (U) immobilization mechanisms in reducing environments. In particular, the long-term behavior of noncrystalline U(IV) species and their possible evolution to more stable phases in subsurface conditions is poorly documented, which limits our ability to predict U long-term geochemical reactivity. Here, we report direct evidence for the evolution of U speciation over 3,300 y in naturally highly U-enriched sediments (350–760 μg · g−1 U) from Lake Nègre (Mercantour Massif, Mediterranean Alps, France) by combining U isotopic data (δ238U and (234U/238U)) with U L3-edge X-ray absorption fine structure spectroscopy. Constant isotopic ratios over the entire sediment core indicate stable U sources and accumulation modes, allowing for determination of the impact of aging on U speciation. We demonstrate that, after sediment deposition, mononuclear U(IV) species associated with organic matter transformed into authigenic polymeric U(IV)–silica species that might have partially converted to a nanocrystalline coffinite (UIVSiO4·nH2O)-like phase. This diagenetic transformation occurred in less than 700 y and is consistent with the high silica availability of sediments in which diatoms are abundant. It also yields consistency with laboratory studies that proposed the formation of colloidal polynuclear U(IV)–silica species, as precursors for coffinite formation. However, the incomplete transformation observed here only slightly reduces the potential lability of U, which could have important implications to evaluate the long-term management of U-contaminated sediments and, by extension, of U-bearing wastes in silica-rich subsurface environments. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Diagenetic aging; Lake sediments; Noncrystalline species; Uranium; Uranium isotopes
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180910
作者单位	Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, UMR 7590 Sorbonne Université-CNRS, MNHN-IRD (Museum National d’Histoire Naturelle-Institut de Recherche pour le Développement), Paris, 75005, France; Institut de Radioprotection et de Sûreté Nucléaire, PSE-ENV SEDRE, Fontenay-aux-Roses, 92260, France; UMR 5204, Université Grenoble Alpes, Université Savoie Mont Blanc-CNRS-EDYTEM (Environnements DYnamiques et TErritoires de la Montagne), Le Bourget-Du-Lac, 73370, France; UMR 7154, Université de Paris-Institut de Physique du Globe de Paris-CNRS, Paris, 75005, France; INRAE-Université Savoie Mont Blanc, UMR CARRTEL (Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques), Thonon-les-Bains, 74200, France; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States
推荐引用方式 GB/T 7714	Lefebvre P.,Gourgiotis A.,Mangeret A.,et al. Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years[J],2021,118(4).
APA	Lefebvre P..,Gourgiotis A..,Mangeret A..,Sabatier P..,Le Pape P..,...&Morin G..(2021).Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years.Proceedings of the National Academy of Sciences of the United States of America,118(4).
MLA	Lefebvre P.,et al."Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years".Proceedings of the National Academy of Sciences of the United States of America 118.4(2021).