Assessment of the Ra-226 and Ra-228 Content in the Bottom Sediments of the Kolva and Usa Rivers (Bolshezemelskaia Tundra of the Nenets Autonomous Region and the Komi Republic)

An assessment was made of the content of natural radionuclides Ra-226 and Ra-228, as well as petroleum products, in the bottom sediments of the Kolva and Usa rivers (Bolshezemelskaia tundra of the Nenets Autonomous Region and the Komi Republic). The values of the specific activities of the studied radionuclides, their isotope ratios, the concentration of petroleum products are obtained, and the correlation dependences of the specific activities of Ra-226 and Ra-228 on the concentration of petroleum products are established. It has been demonstrated that certain sections of the Kolva river are characterized by increased content of Ra-226 in bottom sediments. It was concluded that the likely source of radionuclide entry into bottom sediments is the entry of oil and gas waste into surface waters.