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

Abstract

The activity concentrations of ⁴⁰K, ²³⁸U, ²³²Th and ¹³⁷Cs 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 ¹³⁷Cs activity increased with altitude in samples of soil, grass, hay and cow, sheep and goat milk. On the contrary, ⁴⁰K activity decreased with altitude in samples of soil, grass and hay. The highest activity concentrations of ¹³⁷Cs were found in bioindicators: sheep meat, venison, wild boar meat, moss and mushrooms. These results indicate that ¹³⁷Cs is present in mountain region of Serbia even 20 years after the nuclear accident in Chernobyl. Deposition of ¹³⁷Cs was almost two times higher on the Maljen mountain compared to Tara mountain. An average annual dose arising from ¹³⁷Cs was 7.4 µSv due to ingestion of cow milk and 6.3 µSv due to ingestion of mushrooms at the Maljen mountain.