Investigation of the potential of fungi for precautionary radiation protection in soil

Due to the multifaceted use of radionuclides in research, medicine and industry, there is an increased risk of a release into the environment during the extraction and use of radioactive materials, but also during the storage of the resulting radioactive waste. If radionuclides are released into the soil, they can migrate through soil layers to the groundwater or can be absorbed by crops. In any case, it endangers the environment, animals and humans. For this reason, an effective precautionary radiation protection method must be found which can limit the mobility of possible released radionuclides in the environment.
Since the Chernobyl accident at the latest, it became clear, that fungi influence the migration behavior of radionuclides in the soil by accumulating them in large quantities. Due to other positive properties of fungi, such as the spread of one organism over several square kilometers and their high life expectancy, they provide a good basis for a bio-based precautionary radiation protection. Nevertheless, previous studies have also shown, that the effectiveness of radionuclide accumulation depends on the respective fungal strain [1-3].
For this reason, the molecular interactions of four different fungi with uranium were investigated and compared.
First TEM and STEM images of the fungus Schizophyllum commune, which is widely used as a model organism, show mineralization of uranium in form of needles at the cell membrane. Energy-dispersive X-ray spectroscopy analysis and time-resolved laser-induced fluorescence spectroscopy (TRLFS) have shown, that uranium is mineralized with phosphate. A second fungus, called Leucoagaricus naucinus, shows a different form of mineralization and localization of uranium in the cell. However, first TRLFS experiments suggest that it is a phosphate mineral as well. Together with two other fungi, Pleurotus ostreatus and Macrolepiota procera, a better understanding of the interactions of different fungi with radionuclides will be generated in order to evaluate the potential of fungi for the precautionary radiation protection of soils and to lay the basis for the development of a practicable process.