Distribution and migration of cesium and strontium radionuclides in Estonian scots pine stands

Radioactive pollution from the Chernobyl NPS reactor accident in 1986 has wide scale impact through radionuclides fallout over large areas. We used mushrooms, macrolichenes, mosses and pine needles, forest litter and soil for the investigaton of 137Cs and 90Sr accumulation and migration in pine ecosystems. Systematic collections were made on 63 field sites, total amount of samples analyzed is 350. Highest concentrations of radiocaesium were determined in mushrooms (41.8 kBq/kg) in north-east of Estonia, in macrolichens at the Lahemaa National Park (6.2 kBq/kg). At the Rumpo Botanical Reserve the level of radiocaesium exceeded background concentration (1985) 1.3-1.8 times and at the Koljaku 4.0-4.4 times. During five years of observations (1986-1991) decrease of radionuclides pollution revealed 15 times the Rumpo and Koljaku. Radiostrontium concentrations in different ecosystem compartments all over the territory did not exeed harmful levels. (author). 2 tabs