ОСОБЕННОСТИ РАСПРЕДЕЛЕНИЯ РАДИОНУКЛИДОВ В НАЗЕМНЫХ ЭКОСИСТЕМАХ КАШТАНОВОЙ ЗОНЫ В УСЛОВИЯХ РОСТОВСКОЙ ОБЛАСТИ

Abstract

The determination of the radioactivity of soils in settlements and natural territories is necessary to identify areas with an increased level of radionuclide content. The paper is devoted to studying the features of accumulation of natural radionuclides (226Ra, 232Th, 40K) and artificial 137Cs by plants in the conditions of semiarid steppes on the example of the chestnut zone of the Rostov region. Samples of soils and plants selected in the Tsimlyansky, Volgodonsky, Dubovsky and Orlovsky districts of the Rostov region during the 2014-2017 expeditions were used as objects of research. The activity concentration of radionuclides in soil and plants was measured by gamma spectrometric method of radionuclide analysis. It is shown that the distribution of artificial radionuclide 137Cs in the soil cover of the Rostov region, caused by the accident at the Chernobyl nuclear power plant, is extremely uneven and depends on the humus content. Biogenic element 40K accumulates in the surface horizon, also correlating with the humus content. The activity concentration of 137Cs content on 40K is most clearly displayed in the upper layer (0-10 cm). The lowest activity concentration of natural radionuclides is typical for alluvial-meadow soils and salt marshes of lightweight granulometric composition formed in floodplains of rivers and on coastal areas of lake Manych-Gudilo. In chestnut and dark-chestnut soils, the activity concentration of natural radionuclides is almost comparable, since variations in the activity concentration of these radionuclides in these soils are within the measurement error (10-15 %). The aggregated transfer factors from soil to plants for all radionuclides were generally less than 0.4 m2/kg. Variations in radionuclide aggregated transfer factors in the ecosystem are caused by climatic conditions during the selection period and, as a result, by mechanical contamination of soil particles and dust both during rains and during droughts, when the soil begins to dust.