Ядерна фізика та енергетика Nuclear Physics and Atomic Energy   ISSN: 1818-331X (Print), 2074-0565 (Online)   Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine   Languages: Ukrainian, English, Russian   Periodicity: 4 times per year   Open access peer reviewed journal

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D. M. Holiaka^1,*, S. E. Levchuk¹, V. I. Yoschenko², V. A. Kashparov¹, L. V. Yoschenko¹, M. A. Holiaka¹, V. V. Pavliuchenko¹, P. P. Diachuk¹, R. M. Zadorozhniuk¹, V. S. Morozova<sup>1

1</sup>National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine
²Institute of Environmental Radioactivity at Fukushima University, Fukushima, Japan

^*Corresponding author. E-mail address: holiaka@nubip.edu.ua

Abstract: The paper reports results of the study of depots and biogenic fluxes of ⁹⁰Sr and ¹³⁷Cs in the typical coniferous (Scots pine) and deciduous (Silver birch) forest ecosystems of the Chernobyl Exclusion Zone during 2016 - 2018. Data on activity concentrations and shares of the total activity of the studied radionuclides in the components of aboveground and underground biomass and their vertical distributions by 10 cm layers of the soil profile up to a depth of 1 m are presented. The downward and upward fluxes of ⁹⁰Sr and ¹³⁷Cs activity (including the processes of their deposition as a result of growth and formation biomass) are calculated in annual terms. Significantly higher ⁹⁰Sr mobility in elements of forest ecosystems than ¹³⁷Cs is confirmed. The estimated flux values for the investigated forest areas indicate a gradual further increase in the share of these radionuclides in the aboveground biomass components (up to 0.9 %·year^-1 from the total activity in forest ecosystems) owing to the increase of organic matter stocks.

Keywords: ⁹⁰Sr, ¹³⁷Cs, activity concentration, soil, biomass, Scots pine, Silver birch, stand, forest ecosystems.

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