IntroductionAfter discovering an important biological function of selenium, selenium content and its deficiency arestarted to be extensively studied in numerous epidemiological studies that have been conducted inmany countries in the world. In Mongolia, as a country geographically located in unstable climate zone,there are no studies conducted on selenium so far since the last century, except one study determiningselenium deficiency signs in livestock.GoalTo determine selenium (Se) content in Mongolian wheat and livestock meatMaterials and MethodsIn total 30 samples of wheat planted in Dornod, Uvs, Tuv and Selenge aimags of Mongolia and 142samples of Mongolian beef and beef imported to Russia from China, respectively were underwent inlaboratory analysis. Wheat was hold at room temperature to reach the regular weight, and muscletissue of meat was dried in a lofildryer. Dried wheat and meat were then powdered into homogenousconsistency and were kept in air proof polyethylene container at room temperature until being analyzed.Selenium content was determined by fluorometric method [2].ResultsOut of wheat sorts grown in Mongolia, selenium was detected in extremely low level in wheat of Khalkhingol sort of Dornod aimag (7±1 mkg/kg) and Selenge sort of Selenge aimag (8±1 mkg/kg), and in wheatsold in retail outlets of Baruunturuun soum of Uvs aimag (7±1 mkg/kg) and Khongor soum of Darkhan-Uul aimag (8±1 mkg/kg). However, selenium content was relatively higher in wheat samples of Darkhan34 sort of Baruunturuun soum of Uvs aimag (31±5 mkg/kg) and of Altaiskaya sort of Jargalant (29±3mkg/kg) and Bornuur (32±1 mkg/kg) soums of Tuv aimag, and in sample of retail wheat of Sagil soum(29±1 mkg/kg) of Uvs aimag.When determined the selenium content in Mongolian livestock meat, in average, the selenium contentwere 109-296 mg/kg in beef, 94-200 mg/kg in lamb, 120-225 mg/kg in horse meat and 124-197 mg/kg ingoat, and the differences were not statistically significant (p>0.5). The highest selenium content of 400mg/kg was detected in horse meat of Govi-Altai aimag.Conclusion: The selenium content in wheat and livestock meat which are the mean stable food forMongolians is considerably low.

Background: Mongolia is characterized by restricted sources of drinking water and intensive water pollution due to high rates of urbanization, mining industry development, enormous amount of livestock, and ever-growing attempts in domestic production of cereals and vegetables. Among others, Se is the least studied element in Mongolian water resources. Goal: To assess the selenium content of Mongolia’s drinking water depending on its geographical location and to identify areas of environmental risk associated with the chemical composition of the water. Materials and Methods: In the summer of 2017, water samples were collected from 5 aimags (Dornogovi, Tuv, Selenge, Umnugovi, Arkhangai) and Ulaanbaatar city and sent to Moscow, Russia for analysis. Of the collected samples, 19 were groundwater (wells, wells, springs) and 2 were surface water (Tuul River, Selenge River). Results: Based on fluorimetric method of analysis, the first results on Se levels in drinking water of five aimags, Ulaanbaatar, and Erdenet were obtained. Uneven distribution of Se in Mongolia was manifested, the highest Se concentrations being typical for the southern resources (up to 18,600 μg/L) and the lowest, for the Northern ones (up to 0.022 μg/L). ICP-MS data of Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Hg, I, K, Li, Mg, Mn, Na, Ni, P, Pb, Si, Sn, Sr, V, and Zn contents indicate poly-microelementosis existence in the South of Mongolia (Dorno-Gobi aimag) where ground water is characterized by elevated levels of As and extremely high levels of Se, Li, Na, F, Cl, B, and nitrates ions, exceeding maximum permissible levels by 1.86; 4.3; 3.1; 3.1; 2.7; 3.4; and 1.8 times respectively. Toxic concentrations of Se in groundwater of Dorno-Gobi aimag contradict with the published low human serum Se and low content of the element in horseflesh that suggests the possible effect of the above pollutants on Se bioavailability. Conclusion Revealed phenomenon and mosaic distribution of heavy metals in areas with high and low Se content in water resources indicate the need of direct search for Se and other pollutant transfer in food chain in various ecological loading conditions, creation of a map of Se distribution in water resources of other Mongolian regions, and large-scale evaluation of the human poly-elemental status.