Olga Petrovna Kononets

The features of the modern radioecological situation in forest (pine, spruce, birch) and fallow ecosystems in the contaminated (southern part) and background (northern part) territories of the Kaluga region are analyzed in this article. The density of soil contamination of the studied region by natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) corresponds to background levels, while technogenic radionuclide (¹³⁷Cs) significantly exceeds the background value (3 kBq/m²) and ranges from 60,8 to 273,8 kBq/m². Forest ecosystems (especially coniferous) are the most contaminated by ¹³⁷Cs, and fallow ones are the least contaminated. The density of ¹³⁷Cs soil contamination has decreased on average by more than 3 times compared to the initial period after fallouts (1986), but still significantly exceeds the permissible level (37 kBq/m²). The main contribution to the total specific activity of soils, as well as the power of the equivalent absorbed dose, is made by ¹³⁷Cs in the ecosystems of the contaminated areas, and by ⁴⁰K - in the ecosystems of background areas.