Selenium in natural-anthropogenic geosystems of mining areas of Transbaikalia

In connection with the problem of selenium deficiency and the widespread development in Transbaikalia of white muscle disease in domestic ungulates, cardiac arrhythmia and cancer in humans, a comparative study of the selenium content in soils and ore dressing tailings of tailing dumps and plants growing here is very relevant. Selenium is a common companion of sulfur and almost always accompanies it in natural sulfides or creates its own mineral phases. In Transbaikalia, where ore deposits are widespread, the main useful components of which are part of sulfides, which are the main carriers of selenium, selenium deficiency, it would seem, should not be. Therefore, the study of the prevalence of selenium in the region and its distribution in the components of the landscape is very important. On this basis, the object of this work is related components of the landscape: mineral deposits ^soil (technosity)^wild plants, vegetables. The subject of the study is the distribution of selenium in these components of landscapes. The results of the study. Selenium minerals are present in the ores of polymetallic, gold-polymetallic, tin-polymetallic, tungsten and molybdenum deposits. Its contents are also found in sulfides (molybdenum, pyrite, chalcopyrite, galena, sphalerite, tetradimite, bismuthin, lillianite, altaite, galenobismuthite, sulfosols) in amounts of 0.000 n-13.8 %. These are mainly hundredths - thousandths of a percent, and they reach their maximum in tetradimite (4.9 %) and galenobismuthite (13.8). However, the prevalence of minerals with relatively high Se content is less than 0.001 % and its main carriers are galena, sphalerite, molybdenum and chalcopyrite. The average contents in the ores are (ppm) from 0.5 for pyrite-antimonite-ferberite-quartz ore to 8.0 for molybdenum-chalcopyrite-feldspar-quartz ore with a variation of the concentration coefficient relative to the Clark of the earth's crust from 10 for the W deposits to 160 of the Zhireken Mo deposit. The Se content in soils is 0.3-3.46 ppm with a concentration coefficient of 6-78.5, in technosoils - from 0.3 to 3.1 with a concentration coefficient of 2-90. Se recovery depends on the type of deposits being developed. The content of Se in the terrestrial parts of plants varies (ppm) from 0.004 to 0.21. The maximum content of it in plants of soils (0.02 ppm) and ore dressing tailings (0.07-0.21 ppm) of tin-polymetallic deposits, 0.01-0.03 for molybdenum and 0.02-0.04 ppm of gold ore. A tendency to increase the coefficient of biological absorption in plants growing on ore dressing tailings, compared with those on soils and background areas (from 0.02 to 0.42). It is established that there is no dependence between it and the Se content in soils and ore dressing tailings, which is due to the different ratios of mobile and stationary forms of its presence in soils and ore dressing tailings.

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