Vertical distribution of Cs-137 in alluvial soils of the Lokna River floodplain (Tula oblast) long after the Chernobyl accident and its simulation

摘要

Profiles of vertical Cs-137 distribution in alluvial meadow soils on the low and medium levels of the Lokna River floodplain (central part of the Plavsk radioactive spot in Tula oblast) 28 years after the Chernobyl fallout have been studied. A significant increase in the Cs-137 pool is revealed on the low floodplain areas compared to the soils of interfluves due to the accumulation of alluvium, which hampers the reduction of the total radionuclide pool in alluvial soils because of radioactive decay. The rate of alluvium accumulation in the soil on the medium floodplain level is lower by three times on average. An imitation prognostic model has been developed, which considers the flooding and climatic conditions in the region under study. Numerical experiments have quantitatively confirmed the deciding role of low-mobile forms in the migration of maximum Cs-137 content along the soil profile in the absence of manifested erosion-accumulation processes.