Transformation of the Chornobyl NPP cooling pond: radioecological situation and its impact on the blood system of small rodents.

Abstract

Purpose: To assess the radioecological consequences of the technogenic transformation of the Chornobyl NPP cooling pond aquatic ecosystem and its impact on the blood system of Myodes glareolus, a typical small rodent species in the Chornobyl exclusion zone.

Materials and methods: Animals were captured in the drained areas of the cooling pond and nearby areas. Radiometric surveys of the animals' natural habitat and soil sampling were conducted. γ-β-spectrometry was used to measure radionuclide levels (¹³⁷Cs and ⁹⁰Sr) in soil and animal bodies. Absorbed dose rates were calculated. Blood smears, bone marrow and spleen imprints were prepared and stained using the standard Pappenheim method.

Results: Activity of ¹³⁷Cs and ⁹⁰Sr in soil and animal samples, external/internal doses in animals were estimated. Radioecological assessment showed that radionuclide contamination in the drained areas did not exceed that of the adjacent territory. In exposed animals, similar hematopoietic alterations were observed, including disrupted differentiation and maturation of bone marrow cells, particularly in erythroid and granulocytic lineages. However, these blood abnormalities were less pronounced in animals from the drained zones.

Conclusions: Draining the cooling pond, despite the expected high radionuclide concentrations in bottom sediments, did not cause significant changes in surface soil contamination. While bank voles showed deviations in blood parameters compared to reference values, differences between exposure groups were generally not significant. These findings support continued monitoring of radiobiological effects associated with the transforming of radiation-contaminated aquatic ecosystems into terrestrial.