Зміна вмісту 137CS у чорниці (Vaccinium myrtillus L.) у лісах Полісся України з часу аварії на ЧАЕС

The article presents the results of a study of the long-term dynamics of radioactive contamination of the most common berry plant in the forests of Ukrainian Polissia – European blueberries. Due to their nutritional and medicinal properties, blueberries are widely used by the local population for their own needs, which increases their role in the radiation exposure of the population of the region. The studies were conducted in wet subor (Querceto-Pinetum) – the central part of the ecological area of European blueberries; the sampling areas were characterized by considerable variability in the density of radioactive contamination of soil in 1991 – from 74 to 696 kBq/m2. Forest stands had such taxation characteristics as of 1991: composition – 10P, age 40-50 years, fullness 0.7-0.8. The specific activity of 137Cs in European blueberry berries at all permanent sampling areas was higher than the value of this indicator in its vegetative aboveground phytomass – by 1.1-1.7 times. This is probably due to its biological characteristics. During the observation period, there was a significant decrease in the radioactive contamination of European blueberries: in fresh blueberries by 3.7-8.3 times, in dry aboveground phytomass – by 8.2-19.2 times. The values of the transition coefficients for aboveground phytomass and fresh blueberries in 1994 were 49.2-178.1 and 8.9-34.3 m2kg-1·10-3, respectively. The flow of 137Cs to blueberries continues to be quite intense in 2016: the values of the transition coefficients for fresh and dry berries ranged from 6-8 and 24-61m2kg-1·10-3, respectively, and for dry above-ground phytomass – 17-53 m2kg-1·10-3. 137Cs vertical migration from upper to deeper soil layers continues. In 1991, the bulk of the total radionuclide activity in wet subors was concentrated in half-decomposed and decomposed layers of forest floor and 0-2 cm layer of mineral the soil (about 60-70 %). In 2016, the highest value of this indicator is characteristic for the upper 10 cm layer of humus-eluvial horizon – 69.87 %, which is 1.3 times more than in 2000 (54.91 %). This soil layer contains the root systems of many forest plants, including European blueberries, which increases the intensity of the radionuclides flow to them.