Essential Element Silicon in the Waters of the North Caucasus

Background . Silicon, being an indispensable component, is found in natural waters in various forms: soluble salts, colloids, and suspended particles. Despite the fact that the formation of soluble silicon compounds from silica-containing minerals occurs slowly due to hydrolysis and weathering, its concentration in some waters may exceed acceptable standards, which is confirmed by scientific research. An innovative study on the concentration of silicon and silicon dioxide in reservoirs of the Kabardino-Balkarian Republic has been conducted. The obtained results were subjected to a comparative assessment with the regulatory hygienic requirements for reservoirs suitable for drinking and fishery use. The field of research. As part of the study, three key geomorphological zones of the Kabardino-Balkarian Republic and nine administrative units located on its territory were selected for study: the mountainous zone of Elbrus, the foothill zone of Chegema, and the plain zone, including Baksan, Tersky, Prokhladnensky, Urvansky, Maysky, Lesken, and Nalchik districts. The aim of the study . The research included the determination of sanitary and hygienic standards for the silicon content in different types of waters; the establishment of sampling points for water bodies in various geomorphological zones, followed by their fixation on a schematic map in the Axiom 5 program; as well as the determination of the quantitative content of silicon (Si) and silicon dioxide (SiO 2 ). Material and methods . Silicon was analyzed using the spectrophotometric method on the UNICO-2804 device, with the formation of yellow silicolybdenum heteropoly acid and a blue (reduced) form of molybdosilicic acid. Results and discussion . According to the study results, the Tersky, Prokhladnensky, and Maysky districts are the leaders in terms of the detected total concentrations of silicon in all types of waters studied. Moreover, exceedances of the maximum permissible concentrations for fishery reservoirs (MPCr.x.) and drinking waters (MPCp.v.) were detected at 6 sampling points in the Tersk and Prokhladnensky districts. Conclusions . It has been determined that exceeding the maximum permissible concentrations for silicon is natural and is related to the geology of the catchment areas of the Malka and Terek basins.