Natural Radionuclides in Soils in the Area of the Elkon Plateau Uranium Deposit in South Yakutia

An assessment of the radioecological situation of the preserved geological exploration site at the Elkon Plateau field in the Aldan Highlands was carried out using field radiometry. It was found that the removal of a huge mass of radioactive rocks to the surface from underground mine workings (tunnels, mines) significantly increased the area with an increased radiation background equal to 1.0–12.0 mSv/h and more. Studies have shown that in conditions of anthropogenic pollution, the determining factors of migration, distribution and accumulation of natural radionuclides in soils, in addition to their chemical properties, are a humid climate, genetic features of radioactive ore, the presence of permafrost rocks, soil formation processes and the content of organic matter. Under the prevailing conditions of mountain-taiga landscapes, the intensity of wind scattering of radionuclides from dumps is significantly lower than that of hydrogenic. The active leaching of uranium from the rocks of the dumps led to a sharp disturbance in the soils of the Akin Creek valley of the radioactive equilibrium between radium and the parent radionuclide towards its excess. Prolonged uncontrolled exposure of radioactive dumps to the environment contributed to the accumulation of uranium and radium activities in soils to levels of low (14 252–66 836 Bq/kg) and medium-active (102 294–601 987 Bq/kg) solid radioactive waste. Currently, the problem of environmental pollution with natural radionuclides in the Elkon uranium ore region remains extremely urgent and requires close attention from nature conservation specialists.