Radioecological Situation in the Area of Monazite Placer in South Yakutia

摘要

The results of radioecological investigation of the territory of the Vasilyevka monazite placer in South Yakutia are reported. The processes of deposit development causing the local radioactive pollution of the territory are described. They induce the high exposure rates of gamma-radiation on the ground surface and the elevated thorium concentration in soil and plants. Identified areas of natural thorium concentrations in the alluvial sediments create the extremely high values of dose rate of gamma-radiation on the surface, which is 9-23 times higher than the normal natural radiation background. The scales of wind dispersion of thorium from pollution source are estimated on the basis of its vertical distribution in a soil profile of podbours.