Radioactivity of Surface Marine Sediments of Chaun Bay: Analysis of Natural and Anthropogenic Factors

The paper presents data on the spatial distribution of the active concentration of natural (²³²Th, ²²⁶Ra, and ⁴⁰K) and anthropogenic (¹³⁷Cs) radionuclides in the surface layer of bottom sediments in Chaun Bay of the East Siberian Sea. The measured active concentration of ²³²Th and ²²⁶Ra was typical of bottom sediments of the Arctic coastal shelf zone and corresponded to the global level. The level of ¹³⁷Cs activity in bottom sediments showed the absence of local sources of anthropogenic pollution in Chaun Bay, while the mean ⁴⁰K activity concentration was 1.8 times higher than the global. The results of statistical analysis of the data obtained showed that the dynamics of river runoff, thermal abrasion, and currents, as well as aeolian and ice transport of sedimentary matter, were the main factors that determined the differences in the behavior of the studied radionuclides in the surface bottom sediments of Chaun Bay.