Towards the Issue of Estimation of the Cesium-137 Deposit in Upper Soil Layer When Studing Soil Runoff

Abstract

When the radiocesium method (detection of the Chernobyl origin cesium-137 radioactivity) is applied to determine soil losses on arable slopes during the post-Chernobyl period, the problem can be introduced as the benchmarking of the cesium (cesium-137) deposit measured in Bq/kg. The quantitative assessment of the soil runoff and runoff intensity is based correspondingly on computational models, which describe dependencies between the changes in the cesium deposit and the runoff parameters. Determination of the cesium deposit have to be carried out over the entire depth of the isotope penetration along the soil profile. However, our studies have shown that in the area of arable gray forest soils (in areas of outwashed soils of thalwegs and watershed surfaces) it is possible to determine the soil runoff intensity using data on the cesium deposit in the 0-20 (0-22) cm arable horizon. We are describing the results of the accuracy estimation in the case of cesium specific radioactivity determining using the arable horizon soil samples. Comparison of the specific radioactivity of cesium in the 0-20 cm and 0-50 cm horizons shows that only in the accumulation zones the unaccounted part of the cesium deposit (deposit in under the 20 cm horizon) can achieve 32.8%. In the areas of outwashed soils this unaccounted part is not exceed 16.2%. Therefore, the specific radioactivity of gray forest soil (sampled in the thalwegs in a 0-20 cm horizon) can be used to estimate soil losses due to erosion on arable slopes.