2019,    N 4 (38)    

ECOLOGY

Zakharikhina L., Litvinenko Y.

Radioecological features of the soil and vegetation cover of the Mzymta river valley of the Sochi Black Sea coast

The study of the General radioecological features of the soil and vegetation cover of the Mzymta river valley of the Sochi black sea coast (the location of the new highways and Railways of the Olympic construction in 2014) revealed a natural alkaline geochemical barrier in the average flow of the river, caused by the change of rocks of the territory: neutral mudstones and siltstones to alkaline carbonate. When the environment changes to alkaline with the subsequent deposition of chemical elements (including radioactive) from natural solutions (the decrease in the content of elements in the waters of the river is established), Th and U sorption occurs by soils and plants. In regional conditions on the geochemical barrier, more intensive sorption by soils is established for U relative to Th, for mosses the reverse tendency is characteristic. The geochemical barrier is a promising object for monitoring possible changes in soil and vegetation cover under increasing technogenic load. In General, a stable qualitative, relatively rich (in comparison with Clark’s) geochemical composition of soils and plants within the entire valley of the river from its sources to its estuary part is established for the territory. There were no obvious geo - and radiochemical anomalies associated with the conditions of technogenesis in the soil and vegetation of the valley. The power level of exposure dose of gamma radiation at the Earth's surface (on average 20-27 µr / h in the mountainous area and 9-17 µr / h in the gentle slope) is inferior to the natural level of this indicator for the open mountain areas of Central Russia. Taking into account these regional features, two factors of formation of geo - and radiochemical characteristics of the soil and vegetation cover of the territory can be distinguished. The first is the known geochemical richness of the rocks of the subtropical black sea coast, which is reflected in the composition of soils and plants (increased Clark’s concentrations for most of the chemical elements). The second is the absence of industrial facilities of technogenesis on the territory of the resort infrastructure and small settlements of the river valley, which can significantly change the composition of soils and plants formed under the influence of a stronger natural factor in this case.

Keywords: RADIOECOLOGY, THORIUM AND URANIUM, ALLUVIAL SOILS AND PLANTS, EXPOSURE DOSE OF GAMMA RADIATION AT THE EARTH'S SURFACE