Ukrainian Journal of Forest and Wood Science

Ground lichen flora, as part of forest ecosystems, is a man-made radionuclides depot procession that can accumulate and maintain long isotopes in thallus. This allows us to consider them as an object of radioactive monitoring of forest ecosystems after major accidents or small release of radioactive substances into the environment. Forest tracts of Polissya Natural Reserve is unique to Woodlands of Ukraine as moss forests are occupied by up to 20% of the area. After the Chernobyl accident, these plantations came under radioactive contamination and have a scientific interest in the area as nature conservation, and Radiology. The aim was to investigate the dynamics of ¹³⁷Cs in ground lichens that grow in dry and fresh forests of Polissya Nature Reserve, and identify factors that affect the process of purification. The work carried out by conventional techniques and includes a number of routing and forwarding, laboratory and spectrometric studies. Selection by lichen species carried out in dry and fresh forests of Polissya Nature Reserve for 2001 - 2015 years according to methods of sampling for spectrometric studies. To determine the leaching of radionuclides from fallout thallus conducted research on sprinkler installation in the laboratory. Distribution of ¹³⁷Cs in different parts of lichens thallus determined by dividing them into 3 parts: top, middle and bottom. Over 15 years in lichen thallus showed decreased specific activity of ¹³⁷Cs in 1,7 3,0 times Pollution of all kinds was below the value of physical decay of 27-50%, which means their gradual clearing through natural processes. In particular, it has the greatest impact physical decay of radionuclides from other factors likely influenced by the leaching and precipitation thallus growth with a gradual transition of the dead in the forest floor. With the ability lichen extract in aqueous solution from 20% to 50% of radionuclides during irrigation can leach from thallus a small number of specific activity (up to 0.005 - 0.02%), which suggests virtually no leaching of ¹³⁷Cs fallout. During the growth redistribution of radionuclides in thallus. As part of a growing young moss during research period, specific activity of radionuclides decreased almost in 2 times. Pollution average of 2-3% less than at the beginning of the study. At the bottom was accumulating the maximum number of radionuclides with a tendency to increase with time at 6-15%. The results of our research, cleaning lichens of cesium is due to physical decay of radionuclides for 15 years was 27.60%. Exceeding this value mainly related to dying transition into the bottom of the substrate thallus. The results allow to predict the dynamics of lichen cleaning from radionuclides in the absence of re-contamination.

lichens, epigey lichen flora, thallus, radiocaesium, extraction, biocenosis