Interactions of Fungi and Radionuclides in Soil

Abstract

Following the development of nuclear weapons and the subsequent evolution of nuclear energy-generating industries, there has been considerable concern regarding the safe storage of radionuclide waste. Widescale release, in the aftermath of nuclear detonations or as the result of malfunction of atomic energy plants and reprocessing facilities, has also been a preoccupation. The International Commission on Radiological Protection recommendations on the ecological aspects of radionuclide release were discussed by Coughtree (1983), in which Heal and Horrill (1983) summarized element transfers within terrestrial ecosystems, highlighting the importance of organic soil horizons and their microbial communities as potential accumulators of both nutrient elements and radionuclides. This was a significant step forward from initial discussions of the impact of radionuclide fallout on ecosystems, where the involvement of fungi in regulating radionuclide movement was limited to one sentence in a paragraph describing radionuclide accumulation in organic horizons of forest soils, which may be related to fungal biomass (Osburn 1967). Now, in a more recent model of radiocesium migration in forest ecosystems, Avila and Moberg (1999) place fungal activity in the pivotal point of the diagonal of their interaction matrix, as one of the important biotic regulators of radionuclide movement in soils. Concerns over global climate change and the limitations of conventional fuels is making the world consider alternative energy sources other than fossil fuels. One of these alternatives, nuclear energy, is already in use in many countries, although its expansion has been shadowed by the explosion of the reactor at Chernobyl, Ukraine in 1986. It is likely, however, that there will be future expansion of nuclear activity, which may lead to an increased possibility of local or widespread nuclear contamination of terrestrial systems. It is, therefore, essential that we have adequate knowledge of the behavior of radionuclides in a variety of environments and enough