The distribution and cycling of 137Cs in forests of the Chernobyl exclusion zone.
Orlov, Oleksandr*,1, 1 Ukrainian Institute of Forestry and Agro-Forest Amelioration, Zhytomyr, Ukraine
ABSTRACT- Research was carried out in the 30-km exclusion zone around Chernobyl Nuclear Power plant to make an inventory of the distribution of 137Cs in various parts of the ecosystem. Three 50-year old Scotch pine forests from dominant habitat types were chosen for this research. Weight characteristics as well as 137Cs specific activity in all forest ecosystem components were measured and the distribution of total 137Cs activity within the three forest ecosystems has been calculated. It was shown that in a dry pine forest of the Cladonio-Pinetum association the total 137Cs activity in the tree canopy was 12 % of the total, while 76% was found in forest litter and mineral soil, 12% in lichens, and less than 1% in the forest understory, moss layer, grass-dwarf-shrub layer, and macromycetes. This is consistent with the distribution found in the forest of the Dicrano-Pinetum association where 137Cs activity in the tree canopy accounted for 12% of the total, and 77.6% was in forest litter with mineral soil. Less than 1% was found in the remaining parts. In the forest of the Molinio-Pinetum association the distribution of 137Cs activity differed slightly from the previous cenosis. In this forest the tree canopy accounted for 15.2%, forest litter with mineral soil accounted for 77.6%, the moss layer 6.6%, and then less than 1% each in forest understory, lichen layer, grass-dwarf-shrub layer, and macromycetes. Thus, the main fraction of 137Cs total activity now is concentrated in the soil and forest litter (more than 75 %). There are 2-3 main components in each forest ecosystem giving almost 98 % of the sum of total 137Cs activity. This knowledge is also very important from the point of view of forest exploitation.
Key words: Chernobyl, Cs, distribution, forest
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