210Po in Сrimean salt lakes

Abstract

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.

Keywords: (210)Po; Bottom sediments; Crimean salt lakes; Dose assessment; Hydrobionts; The Black Sea; Water.