The Impact of Drainage on the Radionuclide Distribution in Peat Deposits of Ombrotrophic Bogs in the Arkhangelsk Oblast

This paper presents the results of a study assessing the impact of drainage and subsequent rewetting processes on the accumulation and specific features of the vertical activity distribution of Cs-137, Am-241, Pb-210, U-234, and U-238 in the peat deposit of an ombrotrophic boreal bog (exemplified by the Ilas bog complex in the Arkhangelsk oblast). The data obtained indicated an extremely low level of radioactive contamination in the studied areas. It was demonstrated that hydromelioration of peat deposits led to changes in activity levels and redistribution of the test series of technogenic and natural radionuclides, which was expressed in the shift and localization of their concentration zone toward the peatland surface. It was established that the transformation of the hydrological regime of the deposits during the drainage of ombrotrophic bog areas enhanced the binding of radionuclides by peat sediments, including due to changes in physicochemical conditions.