Measurement and calculation of radionuclide concentration ratios from soil to grass in semi-natural terrestrial habitats in Greece

Highlights: • Temperate and arid Mediterranean-type ecosystem governs Greece. • Studied regions' climate-type is Csa, Csb and BSk (Koppen-Geiger classification). • Climatic types may be linked to the transfer of radionuclides from soil to grass. • Concentration Ratios of Cesium-137 differ among regions with different climate. • -Unsignificant differences for primordial Radium-226, Radium-228, Thorium-228. The results of the measurements of radionuclide transfer from soil to vegetation (Poaceae spp.) that conducted during 2010–2014, in free-ranged grazing regions in Greece, are presented in this work. The specific activities of ¹³⁷Cs, ²²⁶Ra, ²²⁸Ra and ²²⁸Th radionuclides were measured and the activity concentrations were calculated in samples of soil and grass obtained from several studied regions in Greece. The respective soil-to-plant radionuclide transfer parameters (as Concentration Ratio) were calculated and the results were analyzed in terms of spatial deviation caused by the different climate type among the studied regions, provided that the same plant and soil types are studied. The Concentration Ratios ranged from 0.02 to 2.5 for ¹³⁷Cs, 0.01 to 0.7 for ²²⁶Ra, from 0.07 to 1.1 for ²²⁸Ra, and, from 0.08 to 0.17 for ²²⁸Th. Although, the concentration ratios of the primordial radionuclides show some consistency among the different regions, significant differences are observed for ¹³⁷Cs, which may be particularly attributed to the different climatic types (according to the Koppen-Geiger climate classification) that govern these regions.