210Po in Сrimean salt lakes.

This paper presents the results of radioecological monitoring study of natural radionuclide 210Po in 11 lakes located in different regions of the Crimean peninsula. These investigations of the Crimean salt lakes were conducted for the first time in the history. The main objectives of this work were: to determine the features of the 210Ро behavior in the salt lakes ecosystems, as well as calculation of the doses received by the lakes hydrobionts from α-radiation of absorbed 210Po. Concentrations of 210Po in the water, suspended matter, the bottom sediments and biota were determined by radiochemical processing and α-spectroscopy measurements. The concentrations of dissolved 210Po in the water of investigated lakes were in 0.9-327.1 times higher than in the Black Sea closest regions. The highest concentrations of 210Po in water were determined in the lakes of the Kerchenskaya group. These lakes are located on the territory of Crimea where oil is produced. The 210Ро activity concentrations in the bottom sediments from Crimean salt lakes were comparable with those of the Black Sea coastal zone. Concentration ratio (CR) of polonium in suspended matter ranged from 10 to 104 for different lakes. A significant trend in a decrease of CR values of 210Ро for suspended matter with increasing water salinity was revealed. High levels of 210Po accumulation were noted for adult crustacean Artemia spp. (typical inhabitant of the Crimean saline lakes). The CR of 210Po for adult Artemia spp. reached 105 while the CR of this radionuclide by their cysts was significantly lower. The absorbed doses from 210Po α-radiation calculated for adult Artemia spp. were more than 60 times lower than the permissible dose rate for biota (IAEA, 1992).The obtained results will be used to identify the biogeochemical peculiarities in behavior of the main dose-formative radionuclide 210Po, in the water ecosystems with different salinity, including water reservoirs poorly studied in the radioecological aspect and having extreme condition for the existence of lots of species of hydrobionts, such as hypersaline Crimean lakes.

[Polonium-210 in fishes from the Black Sea].

The specific activity of naturally occurring radionuclide 210Po in main species of the Black Sea fishes and some their organs were used for the calculation of absorbed and equivalent dose rates. The values of the dose in investigated fish depend on their ecological belonging. Maximum values of equivalent dose rates for viscera and, first of all, liver exceed such for the whole body of fishes. But they are significantly lower than the dose rate limit recommended by IAEA for the protection of aquatic organisms from ionizing radiation.