Microbial Influence on Bentonite-Transformation

Bentonites are clay silicates consisting mostly of montmorillonite. Due to their mineral composition, bentonites are characterized by a high swelling capacity and low hydraulic conductivity. Therefore, Bentonite is a promising raw material for serving as a natural clay barrier for the disposal of highly radioactive waste. To address the question, whether and to which extend microbial activity affects the respective parameters, selected bentonites can be supplied with a pore water solution and afterwards incubated for short- and long-term analyses at different temperatures in order to simulate the evolution of microbial activity and the resulting impact on Bentonite-transformation. For characterization the respective Bentonite samples will be analyzed considering their geochemistry, molecular biology and mineralogy – three divisions that influence each other directly. We expect that the obtained results could reveal variations in microbial diversity and a correlation with changes of geochemical parameters which could affect the composition and solubility of minerals, and furthermore the beneficial properties of bentonite. The gained information can be further used to indicate a trend in bentonite transformation, which is a prerequisite for evaluating the influence of prokaryotes on safety-relevant processes and properties in radioactive waste repositories.