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Vertical distribution of Cs-137 in uncultivated soils
HÁJEK, Daniel
As for the long-term contamination, radiocaesium (137Cs) is the most important element. Caesium is absorbed by both human bodies and plants and it stays deposited especially in the surface layers of the soil. The first part of the bachelor thesis includes a theoretical overview relating to the issue being dealt with along with the introduction into the gamma spectrometry. As for the reference books dealing with the issue of the radioactive caesium and its migration in the soil, the samples had been collected in larger layers surface (0 - 5 cm) and bottom (5 - 20 cm) only. However, for the purposes of this thesis, the samples of individual soils were collected in one-centimetre layers, with the aim to find out in which layer of the soil the most 137Cs is occurred, because it is supposed that 137Cs has been within reach of the root zone of plants.The distribution of radionuclides in the soil is affected with several main factors. There are also clear differences between the cultivated and non-cultivated soil. The samples of the measured soils were collected in the Šumava Protected Landscape Area in the surroundings of Kvilda, Horská Kvilda, Modrava, Bučina, Borová Lada, Zadov and Nové Hutě. The result gamma spectrum was evaluated with the high-resolution germanium detector combined with multi-channel analyser in GAMAT at the State Office for Nuclear Safety (SÚJB) in České Budějovice. Based on all measurements it was found out that the largest amount of 137Cs is deposited in the first layer of the soil, however, there is a minimal difference compared with layer two. The most 137Cs is deposited in the surface layers of the soil, which reaches to the plant root zone. Also the distribution of 137Cs in soil is obvious from the obtained data.
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