Accumulation and distribution of long-living radionuclides in the forest ecosystems of the Kyshtym accident zone

The concentration of Strontium-90 and Cesium-137 in soil and woody plants was studied in the Sverdlovsk region of the zone contaminated as a result of the Kyshtym accident in the southern Urals in 1957. In the forest ecosystems under study, the total concentration of strontium-90 varied from 1.5 to 63.4 kBq/m2, while that of cesium-137 did not exceed 13 kBq/m2. Soil contamination resulted in an increase in the concentration of radionuclides in woody plants. Thus, the concentration of strontium-90 in different parts of birch samples was higher than in the controls by a factor of 5–16, while for pine, it was higher by a factor of 2–4.