Past is Prologue: Ancient Glass Analogues for the Long-Term Disposal of Vitrified Nuclear Waste
EMSL Project ID
51400
Abstract
Microbes are ubiquitous in the terrestrial surface and have mastered the art of establishing equilibrium in their localized environment. Samples obtained during an excavation of Broborg, an ancient Swedish hillfort, provide a unique opportunity to study how microbial communities work together to control local chemistry, and how they adapt to colonize anthropogenically-engineered materials over a period of hundreds of years. The project team and EMSL collaborators will examine microbes (prokaryotes and eukaryotes) present on: (i) pre-Viking era glass produced for joining rocks to build the fort; (ii) surrounding heat damaged rock from the vitrification process; (iii) rocks representing the local geology; and (iv) soil in contact with each of these materials. EMSL microscopy, spectroscopy, tomography, and diffraction capabilities will allow detailed characterization of the interface between the vitrified material and the altering environment, to determine the local biogeochemical influences on glass structure, chemistry and mineralogy. Results obtained will provide a greater understanding of the extent to which microbes influence both anthropogenically-engineered and natural materials, by either: (i) protecting them by controlling their environment, or (ii) enhancing corrosion to obtain nutrients. This international project team has a unique opportunity to take advantage of vitrified material and soil samples obtained from the excavation of a culturally and ecologically sensitive site in Sweden by a multi-institutional team. Broborg and its 1,500-year-old vitrified fortifications, can be considered as a habitat analogue for the near-surface disposal of low activity radioactive waste glass. Thus, characterization of the alteration layers on the ancient glass will transform the understanding of long-term glass corrosion, and results obtained will be used to inform contaminant release models from radioactive waste repositories. An initial assessment of the pre-Viking era Swedish glass samples was performed at EMSL and indicated that microbial colonization may play a primary role in the alteration of the glass. As such, the team will combine geochemical data with bioinformatics to develop a predictive understanding of microbial/geochemical weathering processes. Specific aims would include the following: 1) to identify processes and/or microorganisms that may have accelerated or inhibited long-term weathering of materials in various states of anthropogenic alteration -- native, fire-cracked, vitrified rock -- as a function of depth in the critical zone; and 2) to identify ways in which anthropogenic alteration of host rock has affected soil development, soil chemistry, and soil microbiology over 1,500 years.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2020-10-01
End Date
2022-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members