Specific Activity of Radionuclides in Cryoconite Sediments of Glaciers of the Central Caucasus (Tsey, Skazka, Bezengi), Russia

Nowadays, much attention has been paid to the study of the specific activity of radionuclides on the surface of glaciers. This work is devoted to the study of specific activity of natural (K-40, U-235, U-238, Th-232) and anthropogenic (Cs-137) radionuclides in cryoconites of glaciers of the Central Caucasus. The work shows that the activity of the investigated natural radionuclides in the cryoconites of the glaciers we studied is comparable to data from Arctic glaciers, somewhat lower than on Mount Elbrus and Transcaucasia, and significantly lower than on Alpine glaciers. The study revealed that the glaciers of the Central Caucasus (Tsey, Skazka, and Bezengi) exhibit low values of specific activity of anthropogenic radionuclide Cs-137 and average from 0.51 Bq/kg (Bezengi) to 2.61 Bq/kg (Skazka). On the contrary, high and very high concentrations of this radionuclide were revealed in cryoconites of glaciers from other regions, especially in the Alps, the Arctic, and Transcaucasia. Thus, our data confirm the results of previous studies conducted on glaciers of the Central Caucasus, which indicated that the activity of natural radionuclides in cryoconites of glaciers of the Central Caucasus is comparable to the world average values, while the anthropogenic radionuclide Cs-137 is much lower.