Microbial community changes induced by uranyl nitrate in bentonite clay microcosms
Metadatos
Mostrar el registro completo del ítemAutor
López Fernández, Margarita; Vílchez Vargas, Ramíro; Jroundi, Fadwa; Boon, Nico; Pieper, Dietmar; Merroun, Mohamed LarbiEditorial
Elsevier B.V.
Materia
Bentonite Microcosms Microbial diversity Uranium Biomineralization
Fecha
2018Referencia bibliográfica
Lopez-Fernandez, Margarita; Vilchez-Vargas, Ramiro; Jroundi, Fadwa; Boon, Nico; Pieper, Dietmar; Merroun, Mohamed L. Microbial community changes induced by uranyl nitrate in bentonite clay microcosms. Applied Clay Science 160 (2018) 206–216. [http://hdl.handle.net/10481/54804]
Patrocinador
This work was funded by the ERDF-financed Grants CGL-2012- 36505, CGL2014-59616-R (80% finding by FEDER), BES-2010-032098 and EEBB-I-14-08420 (Ministerio de Ciencia e Innovación, España).Resumen
Deep geological repository (DGR) is one of the internationally accepted options to dispose radioactive wastes.
Bentonite formations from Almeria, Spain, were selected as reference material for artificial barriers for the future
Spanish repository. However, the safety of this long-term disposal could be compromised not only by physicochemical
factors but also by microbial processes. The highly radioactive waste must be safely stored at least for
100,000 years for the radioactivity to decrease to similar levels to those of natural uranium. To simulate a
scenario where the mobilization of radionuclides from the repository to the host formations may occur, longterm
microcosms were studied. After being exposed to uranyl nitrate for 5 months, the response of the bentonite
microbial community to the addition of this radionuclide was evaluated. High throughput 16S rRNA gene sequencing
revealed that the structure of the microbial community after the uranyl nitrate treatment differs to that
of the control microcosms. The microbial diversity was dominated by Firmicutes and Proteobacteria. Moreover,
after the uranyl nitrate treatment OTUs annotated as Paracoccus and Bacillus were highly enriched. The mineralogy
of bentonites was not affected by the uranyl nitrate treatment as was demonstrated by X-ray diffraction
analysis. In addition, the study of uranium-bacteria interaction revealed the ability of isolates to biomineralize
uranium as uranium phosphate mineral phases. Thus, the changes induced by the release of uranium in the
microbial population may also affect the mobility of this radionuclide, making it less mobile and therefore less
harmful for this environment.