Consequences for the Industry of Radioactive Contamination Accompanied by the Dynamics of 137Cs and 40K Movement in the Environment

Radioactive pollution entered the ecosystems during the nuclear test in the 1950s and 1960s and in Croatia largely after Chernobyl accident in 1986. Cs-137 and K-40 can be stored in different parts of the trees but also in the upper surface layer of soil under the trees. This study was aimed at determining the intensity and dynamics of Cs-137 and K-40 radionuclides in chestnut tree tissues (Castanea sativa Mill.) in the vicinity of Petrinja (Croatia). The samples were taken in 2003, 2004 and 2016 and the samples activities were measured by gamma spectrometric method. During the winter, the highest activities were recorded in the top shoots, leaves, fruits and hedgehogs, while in the vegetation season, the highest activities were in the top shoots and dead bark. Also, a decrease in Cs-137 concentrations was observed in the rings with increasing age of the rings. Significant increased values of activity were measured in samples of the youngest and physiologically most active parts of trees, compared to the least physiologically active where concentrations were lower. Cs-137 was biogeochemically retained almost entirely in the surface layer. The obtained results suggest that the chestnut tree does not distinguish Cs-137 and K-40, as two homologous elements.