Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

Hugo Moors, Natalie Leys, Olivier X. Leupin, Rizlan Bernier-Latmani, Alexandre Bagnoud, Katinka Wouters, Simcha Stroes-Gascoyne

Research outputpeer-review


Microbiological studies related to the geological disposal of radioactive waste have been conducted at the Mont Terri rock laboratory in Opalinus Clay, a potential host rock for a deep geologic repository, since 2002. Themetabolic potential of microorganisms and their response to excavation-induced effects have been investigated in undisturbed and disturbed claystone cores and in pore- (borehole) water. Results from nearly 15 years of research at the Mont Terri rock laboratory have shown that microorganisms can potentially affect the environment of a repository by influencing redox conditions, metal corrosion and gas production and consumption under favourable conditions. However, the activity of microorganisms in undisturbed Opalinus Clay is limited by the very low porosity, the low water activity, and the largely recalcitrant nature of organic matter in the claystone formation. The presence of microorganisms in numerous experiments at the Mont Terri rock laboratory has suggested that excavation activities and perturbation of the host rock combined with additional contamination during the installation of experiments in boreholes create favourable conditions for microbial activity by providing increased space, water and substrates. Thus effects resulting from microbial activity might be expected in the proximity of a geological repository i.e., in the excavation damaged zone, the engineered barriers, and first containments (the containers).
Original languageEnglish
Pages (from-to)343–354
Number of pages13
JournalSwiss Journal of Geosciences
Issue numberS1
StatePublished - 24 Feb 2017
Event2017 - TM - 20th Anniversary Technical Meeting of the Mont-Terri-Rock-Laboratory - Porrentruy
Duration: 10 Feb 201611 Feb 2017

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