Macromycetes as bioindicators of radionuclide contamination in forest ecosystems

The aim of the paper is to determine the specific activity of radionuclides in macromycetes in Ulyanovsk region forest ecosystems exposed to radiation after the Chernobyl accident. Materials and Methods. The fruiting bodies of macromycetes (soil and wood-destroying fungi) gathered in the radioactive contaminated territories served as the material for the research. The authors determined the specific activity of Cs-137, K-40, Ra-226, Th-232 radionuclides. The study was conducted during the growing season in the Ulyanovsk region forests (Inza and Karsun districts). For comparison, fungi samples (control) were also gathered in the Novospassky region, where the excess background radiation was not observed. Trial sites with similar forest growth conditions were selected. The specific activity of radionuclides in the fungi fruiting bodies was determined according to Guidelines 2.6.1.1194-03. Results. In soil fungi, the highest average Cs-137 specific activity was found in the fruiting bodies of Leccinum scabrum, K-40 and Ra-226 specific activity - in the fruiting bodies of Suillus luteus, and Th-232 specific activity - in the fruiting bodies of Macrolepiota procera. In wood-destroying fungi, the highest average Cs-137, K-40 and Ra-226 specific activity was observed in the fruiting bodies of Fomitopsis pinicola, and the highest Th-232 specific radioactivity - in the fruiting bodies of Coriolus versicolor. The average specific activity of all radionuclides in the mushrooms from the radioactive contamination territories (Inza and Karsun districts) was mainly higher than in the control (Novospassky district). In the studied samples of soil and wood-destroying fungi, excess radioactive concentrations were not found. Conclusion. Forest mycobiota can be used as a bioindicator of radioactive environmental pollution.