Assessment of Changes in Chernobyl Contamination and Erosion Rates for Arable Soils Using Resampling Method

Abstract

The transformation of radioactive contamination of agricultural lands with ¹³⁷Cs isotope is one of the evidences of soil erosion. Changes in the radionuclide content and the corresponding rates of soil loss can be assessed quantitatively by repeated soil sampling at key sites over long time intervals. Being highly labor-consuming, such studies are few in number; they have not been conducted previously in the zone of intense Chernobyl contamination in the Central Russia. The method of repeated sampling (resampling) was used in 2023 within the plowed slopes of a small catchment in the southern part of Tula region, 26 years after the first sampling in 1997. The changes in ¹³⁷Cs deposits (kBq/m²) that occurred during this period turned out to be statistically significant, with an average reduction of more than 10%. According to a proportional erosion conversion model based on relative changes in ¹³⁷Cs deposits, the average annual rate of washing off was estimated at 11.7 t /ha. Such values of soil loss are comparable in general with the previously published results of independent mathematical modeling for this area. Thus, the use of resampling method, including that at new sites, appears to be promising for assessing the rate of soil loss. In addition, it permits us to verify the existing erosion models and to trace long-term trends in the spatial transformation of radioactive contamination.