| Реферат: | eng: The relevance of the research is caused by the need to study and monitor the ecological and geochemical status of a complex mineral salt deposit of Ebeity Lake. The total industrial reserves of sodium sulfate (mirabilite) in the lake water are 36,89 million tons. In addition, this lake is of interest as a deposit of therapeutic mud, as well as the crustaceans Artemia Salina L. and their cysts. The aim of the study is to determine the main features of macro-, micro- component, organic and mineral composition of the lake Ebeity, as well as to determine the hydrogeochemical processes affecting the distribution of organomineral complexes of elements. Research methods. The lake was studied in summer 2015. The lake and porous waters, as well as bottom sediments were analysed using mass spectral methods, as well as the methods of atomic absorption, flame emission, potentiometry, titration, etc. The study of bottom sediments was also carried out using the X-ray powder diffractometry method with mandatory control of the composition of typical solid samples by X-ray fluorescent analysis using synchrotron radiation with registration on a Si (Li) detector. The results of the studies showed that Ebeity Lake refers to the SO4-Cl-Na composition, the pH of the lake during the sampling period was 5,7, the lake was characterised by anoxic condition. The pore waters of bottom sediments do not differ from the lake water in their major composition, but the concentrations of trace elements are 2-8 times higher than the values in the lake. The study of complexation of elements in lake water shown that most of iron, copper, uranium and thorium is bound to a high molecular organic matter that allows presuming the impossibility of formation of such minerals as goethite, chlorite and Cu (met), obtained during thermodynamic calculations. The results obtained at simulation allowed us to construct a sequence of formation of evaporite minerals in the lake: Na2SO4 center dot 10H(2)O+Na2Ca(SO4)(2)-> Na2SO4+Na4Ca(SO4)(3 ->)2H(2)O -> NaCl+Na4Mg(SO4)(2)center dot 4H(2)O. A study of the mineral composition of bottom sediments showed the presence in solid phase of quartz as the main phase, impurities of NaCl, small admixtures of potassium feldspars, plagioclase, and calcite. The salt along the lake and at the bottom is represented by thenardite, a small-medium amount of halite and traces of astrakhanite.
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