GEOECOLOGICAL AND GEOCHEMICAL BASES OF FORMATION OF RADIOACTIVE CONTAMINATIONS IN THE ELKONSKY URANIUM ORE DISTRICT (SOUTH YAKUTIA)

The radiation indicators of rock dumps, ground and surface water, atmospheric air and residential air, as well as alluvial soils of technogenic landscapes of the South Elkon uranium-ore region in the territory of South Yakutia were studied. It has been shown that the most active dumps in their radiation parameters are close to radioactive ores, while the exposure dose rate here is 1600-2150 µkR/h, the effective specific activity of natural radionuclides is 20441-23640 Bq/kg, and the uranium content is 1637-1888 mg /kg. Ranking of the studied dumps according to the degree of radiation hazard showed that only 2 dumps out of 31 (6,4 %) belong to the category of safe, 13 (41,9 %) - to the category of potentially hazardous, and 7 and 9 (22,6 % and 29,0 %) - respectively categories of dangerous and especially dangerous. In the mountainous terrain, cold and humid climate of the study area, these rock dumps, unevenly distributed over an area of about 500 km2 of mountain-taiga landscapes, are the main source of radioactive contamination of air, ground and surface water, and soil cover. At the same time, the maximum values of uranium and radon content in the studied surface and groundwater, respectively, were 8,0 and 32,2·10-5 g/l, as well as 112 and 3090 Bq/l. In the studied technogenic zones, there is a direct relationship between the intensity of pollution of surface waters and alluvial soils drained by them, formed in the floodplains of these watercourses. Key words: rocks, soils, surface and underground waters, air, radiation parameters, technogenic pollution.