It was shown that in the narrow marginal zone (about 6-8 m wide) of a mezotrophic bog, typical for the northern part of Ukrainian Polissya, a transsuperaquatic landscape is formed between transacumulative and superaquatic landscapes. In the transsuperaquatic landscape a complex biogeochemical barrier has been formed. Here, at a short distance, barriers of different types are spatially connected – physico-chemical (sorption, gley etc.) and phytocenotic (all vegetation layers), lateral and radial. It was found that due to lateral 137Cs redistribution among the geochemically connected landscapes of the catena, there was observed the concentration of the radionuclide on the investigated complex biogeochemical barrier. Three biogeochemical barriers were found in the soil – layers of semi-decomposed residuals of mosses, trees and grasses (H0dt), peat (Т1-Т5) and iluvial humic-ferruginous gley horizon (Ihgl), which slow down 137Cs migration both in lateral and radial directions. Generalization of datа on 137Cs radial distribution in the soil of the geochemical barrier shows that analogs of the forest litter (H0 non-decomposed and layer of H0dt – semi-decomposed plant residuals) contained 8.16% of the total 137Cs activity in the soil; peat (0-25 cm) – 17.14%, and the mineral horizons (Ihgl and Pigl) – 74.7%. This distribution testifies about high speed of radial 137Cs migration in the studied soil, insofar as the main part of the total activity of 137Cs has already migrated beyond the boundaries of the peat layers to the mineral horizons. The calculations showed that the main part of the total stock of 137Cs in biogeocenosis on the biogeochemical barrier in the transsuperaquatic landscape was retained in soil – 86.59%, accordingly phytocenosis contained 13.41% of the total stock of the radionuclide. The geochemical transfer coefficient was 0.16, which was close to the corresponding values for the superaquatic landscapes. Significant interspecific differences in 137Cs accumulation were observed in all layers of vegetation. The migration ability of 137Cs in the chains «soil – plant» and «soil – fungi» in the transsuperaquatic landscape was evaluated based on the mean 137Cs transfer factor (TF) values to be 2-20 times higher than that for the eluvial and transeluvial landscapes. This leads to significant excess of the permissible levels of the 137Cs specific activity in medicinal plants, wild berries and edible mushrooms at soil contamination density with 137Cs which is not officially regarded as radiationally hazardous (about two times less than 37 kBq·m-2).
Key words: biogeochemical barrier, transsuperaquatic landscape, biogeocenosis, 137Cs, soil, layers of vegetation, intensity of 137Cs accumulation.
- Аvessalomova, I.A. (1987), Geochemical indexes in the study of landscape. М.: Moscow Univ. publ. 108 p.
- Glazovskaya, М.А. (1964), Geochemical basis of typology and methodology of study of natural landscapes. Moscow: Moscow Univ. publ. 229 p.
- Dolin, V.V. (2004), Selfcleaning of terrestrial ecosystems of Ukrainian Polissya from radioactive contamination. Kyiv. 36 p.
- Korotkova, O.Z. (2000), Accumulation of 137Cs by the main wild berry plants of forests of Ukrainian Polissya. Zhytomyr. 19 p.
- Landscapes of Chornobyl zone and their assessment of migration conditions of radionuclides (1994), Davydchuk, V.S., Zarudnaya, R.F., Mikheli, S.V., Petrov, M.F., Sorokina, L.Yu.., Tkachenko, A.N. Ed. A.M. Marynych. Кyiv: Naukova Dumka. 112 p.
- Molchanova, I.V., Karavaeva, E.N., Kulikov, N.V. (1990), Ecology. 3: 30-35.
- Оrlov, О.О., Dolin, V.V. (2010), Biogeochemistry of cesium-137 in forest-bog ecosystems of Ukrainian Polissya. Кyiv: Naukova Dumka. 198 p.
- Pavlotskaya, F.I., Tiuriukanova, E.B. (1976), Problems of radioecology and biological influence of low doses of ionizing radiation. Syktyvkar: Komi Branch of Academy of Sciences of the USSR. P. 30-45.
- Perelman, А.I. (1975), Geochemistry of landscape. Moscow. 342 p.
- Perelman, А.I. (1989), Geochemistry. Moscow. 528 p.
- Perelman, А.I., Borisenko, Е.N., Vorobjov, А.Е. et al. (1997), Intern. Symp. on Applied Geochemistry of CIS countries. Moscow. P. 137.
- Rodin, L.Е., Remezov, N.P., Bazilevich, N.I. (1997), Guidelines to study of dynamics and biological circle in phytocenoses. Moscow. 145 p.
- Strakh, L.I. (1999), Geochemical barriers of the marginal zone of the bog of Belorussian Polessye and concentration 137Cs on it. Moscow. 24 p.
- Strakh, L.I., Knatko, V.A. (1997), News of Academy of Sciences of Belorussia. Series of Chem. Sci. 3: 77-82.
- Strakh, L.I., Knatko, V.A. (1997), News of Academy of Sciences of Belorussia. Series of Chem. Sci. 1: 79-84.
- Tiuriukanova, E.B. (1979), Modern tasks and problems of biogeochemistry. 17. Moscow. P. 143-150.
- Yunatov, А.А. (1964), Field Geobotany. Eds. E.M. Lavrenko and A.A. Korchagin. Vol. 3. Мoscow-Leningrad: Nauka. P. 9-35.
- Modelling and study of the mechanisms of the transfer of radioactive material from terrestrial ecosystems to and in water bodies around Chernobyl (1996). Luxembourg. 230 p.