Long-term tracking of the microbiology of uranium-amended water-saturated bentonite microcosms: A mechanistic characterization of U speciation
Identificadores
URI: https://hdl.handle.net/10481/93058Metadatos
Mostrar el registro completo del ítemAutor
Morales Hidalgo, Mar; Povedano Priego, Cristina; Martinez-Moreno, Marcos F.; Ojeda, Jesus J.; Jroundi, Fadwa; Merroun, Mohamed LarbiEditorial
Elsevier
Materia
DGR Bentonite slurry Uranium Long-term incubation Microbial diversity Sulfate-reducing bacteria
Fecha
2024-06-26Referencia bibliográfica
Morales-Hidalgo, M., Povedano-Priego, C., Martinez-Moreno, M. F., Ojeda, J. J., Jroundi, F., & Merroun, M. L. (2024). Long-term tracking of the microbiology of uranium-amended water-saturated bentonite microcosms: a mechanistic characterization of U speciation. Journal of Hazardous Materials, 135044.
Patrocinador
This study was supported by the grant RTI2018-101548-B-I00 “ERDF A way of making Europe” to MLM from the “Ministerio de Ciencia, Innovación y Universidades” (Spanish Government). The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 847593 to MLM and the grant FPU20/00583 to the first author from the “Ministerio de Universidades” (Spanish Government).Resumen
Deep geological repositories (DGRs) stand out as one of the optimal options for managing high-level radioactive waste (HLW) such as uranium (U) in the near future. Here, we provide novel insights into microbial behavior in the DGR bentonite barrier, addressing potential worst-case scenarios such as waste leakage (e.g., U) and groundwater infiltration of electron rich donors in the bentonite. After a three-year anaerobic incubation, Illumina sequencing results revealed a bacterial diversity dominated by anaerobic and spore-forming microorganisms mainly from the phylum Firmicutes. Highly U tolerant and viable bacterial isolates from the genera Peribacillus, Bacillus, and some SRB such as Desulfovibrio and Desulfosporosinus, were enriched from U-amended bentonite. The results obtained by XPS and XRD showed that U was present as U(VI) and as U(IV) species. Regarding U(VI), we have identified biogenic U(VI) phosphates, U(UO2)·(PO4)2, located in the inner part of the bacterial cell membranes in addition to U(VI)-adsorbed to clays such as montmorillonite. Biogenic U(IV) species as uraninite may be produced as result of bacterial enzymatic U(VI) reduction. These findings suggest that under electron donor-rich water-saturation conditions, bentonite microbial community can control U speciation, immobilizing it, and thus enhancing future DGR safety if container rupture and waste leakage occurs.