Assessment of radioisotope concentrations of 137Cs and 90Sr in the herbaceous phytocenoses plants of the Dnieper river floodplain ecosystems (northern Ukraine)

Abstract

The experimental data on the ¹³⁷Cs and ⁹⁰Sr concentation in the herbaceous phytocenoses of the Dnieper floodplain ecosystems in northern Ukraine have been discussed. Different radionuclide contents in plants and soils of different ecosystems of the floodplain depends on the herbaceous phytocenoses proximity to the river bed: a higher content of radiocaesium has been found in plants and soils of the meadow and marsh ecosystems, which are close to the river bed, and radiostrontium in the marsh and psamophyte ecosystems. Besides the intensity of radionuclide uptake by plants has been determined as by the soil and the cenotic habitat conditions so the biological characteristics of the species. The species specificity of the ¹³⁷Cs and ⁹⁰Sr accumulation by plants and the direct dependence of the soil-to-plant transfer factor from the density of the floodplain ecosystem contamination with radionuclides have been proved. Our results testified that significant differences in the caesium and strontium distribution were observed between ecosystems, likely influenced by soil characteristics, vegetation types and biomorphs. Our data suggest that the ecosystem type played a significant role, with caesium being most abundant in ruderal ecosystems and least abundant in psamophytic ecosystems, while strontium effects were particularly high in ruderal and psamophytic ecosystems compared to meadows.