Natural and anthropogenic radioactivity in the environment of mountain region of Serbia

Abstract

The activity concentrations of K-40, U-238, Th-232 and Cs-137 have been measured using a gamma spectrometric method in different samples from the environment of two mountains in Serbia (altitude 1000-1100 m), during the period 2002-2007. The mountains Maljen and Tara (popular tourist destinations) are near Belgrade. On mountain Maljen, samples were taken at 4 different altitudes (200 m, 650 m, 1000 m and 1100 m), and on mountain Tara at altitudes of 1000 m and 1100 m. On mountain Maljen it was found that the level of Cs-137 activity increased with altitude in samples of soil, grass, hay and cow, sheep and goat milk. On the contrary, K-40 activity decreased with altitude in samples of soil, grass and hay. The highest activity concentrations of Cs-137 were found in bioindicators: sheep meat, venison, wild boar meat, moss and mushrooms. These results indicate that Cs-137 is present in mountain region of Serbia even 20 years after the nuclear accident in Chernobyl. Deposition of Cs-137 was almost two times higher on the Maljen mountain compared to Tara mountain. An average annual dose arising from Cs-137 was 7.4 mu Sv due to ingestion of cow milk and 6.3 mu Sv due to ingestion of mushrooms at Maljen mountain.