Distribution of Cesium Radioisotopes in Pine Biogeocenoses and the Associated Absorbed Dose Rate of External γ-Radiation

Data on the distribution of Cs and Cs in the main components (forest litter, upper layers of the mineral part of the soil, elements of the aboveground phytomass of woody plants) of pine plantations in the Belarusian sector of the 30 kilometer zone around the Chernobyl nuclear power plant 8 years after the emergency radioactive fallout are presented. Using dosimetric models based on the integration of the dose function of a point radiation source and the numerical solution of the radiation transfer equations, calculations of the absorbed dose rate of external gamma radiation at a height of 1 m above the surface of the forest floor from the radiation of radionuclides contained in the studied components were performed. Satisfactory convergence of the results of calculation and measurement of dose rate in pine plantations has been established. It is shown that different methods for calculating the dose rate from external gamma radiation of radionuclides contained in the same components of biogeocenosis allow us to obtain comparable results. The determining contribution to the formation of the radiation dose rate of Cs and Cs located in the forest floor and 2 upper soil layers of the mineral part of the soil has been established, the contribution of elements of the aboveground phytomass of woody plants does not exceed 2.5%.