Introduction. For the time present, the active substances of many ice-melting agents used in Moscow are technical sodium and calcium chlorides. By degree of impact of sodium chloride on the human body is characterized as a moderately dangerous substance that belongs to the 3rd hazard class. Residents of megacities who remain unprotected from the possible harmful effects of these substances need the compliance of the ice-melting product’s application with appropriate security measures. Our research focused on the presence of these substances and their accompanying components in the transit environment and determining their actual and extreme loads to prevent possible functional changes in the future traffic chain objects. Material and methods. Chloride (Cl-) and sodium (Na+) content in the snow mass samples taken from the sites adjacent to motorways in Moscow were determined using ion chromatography. Other associated elements in the ice-melting agents were detected using inductively coupled plasma mass spectrometry method (ICP-MS). Results. According to the snow mass analysis as an object of transit accumulation and distribution of ice-melting reagents, the authors ranked results and identified clusters with different degrees of contamination for many indices. Selecting the group with very high contamination enabled us determine the indices’ levels that limit the use of deicing reagents. When using sodium-chloride reagents, they are the levels of the specific electrical conductivity (SEC) ≥ 4500 µS/cm, the concentration of chloride anions (Cl- ≥ 2500 mg/l), the concentration of sodium ions (Na+) ≥1500 mg/l, the index of total contamination (Zc).

В статье обоснована актуальность подбора оптимального метода химического анализа атмосферного воздуха с целью идентификации и количественного определения компонентов солей, входящих в состав противогололедных материалов (ПГМ), применяемых в настоящее время в г. Москве в зимний период. Проведена оценка химического состава различных видов ПГМ материалов и выбраны индикаторные ионы для анализа. Приведены результаты собственных экспериментальных исследований по анализу проб атмосферного воздуха, отобранных в зимний период в г. Москве, с использованием различных поглотительных устройств и методов химического анализа (ионная хроматография, масс-спектрометрия с индуктивно-связанной плазмой). Выявлены ограничения использования современных аспираторов в условиях отрицательных температур в зимний период. Показано, что уровень содержания ионов натрия и хлора в атмосферном воздухе г. Москвы значительно превышает соответствующие фоновые показатели природного происхождения. Подчеркнута необходимость продолжения исследований в данном направлении в целях совершенствования подхода к выбору оптимального метода химического анализа и способов отбора проб, что имеет важное значение с точки зрения снижения негативного воздействия ПГМ на окружающую среду и здоровье населения. The paper outlines the relevance of choosing an optimal method for atmospheric air chemical analysis, capable to provide an appropriate identification and quantification of salts ingredients that make up the major part of deicing materials (DMs), currently used in winter period in Moscow. Chemical composition evaluation of various types of DMs has resulted in selection of indicator ions for subsequent analytical procedures. The authors’ own experimental data on analyzing atmospheric air samples collected in winter in Moscow using various absorption devices and chemical analytical methods (i.e. ion chromatography, inductively coupled plasma mass spectrometry) are presented. A series of limitations of applying modern aspirators under conditions of sub-zero winter temperatures are revealed. Sodium and chlorine ion levels in the atmospheric air of Moscow are found to be significantly higher than the corresponding background level of natural origin. An urgent necessity to continue research in this area has been emphasized with the focus on improving the approach for selection of the optimal method for chemical analysis and sampling procedures, which is highly important in terms of reducing a negative impact of DMs on public health and environment.

Introduction. The consequences of uncontrolled use of antibiotics in agriculture are an urgent problem of environmental hygiene. Tetracycline can enter the soil with the urine of domestic animals, inhibit the vital activity of soil bacterial strains and inhibit the processes of enzymatic hydrolysis of urea (carbamide), disrupting the global nitrogen cycle in nature. The lack of both quantitative and qualitative criteria for assessing this influence determined the relevance of the research. Materials and methods. The studies were carried out using the “Stayer” chromatographic system with cationic and anionic separating columns and exclusive analysis methods developed by the authors. When modelling solutions of heavy metals, an atomic absorption spectrometer MGA - 915MD with ETA was used. The objects of research were model solutions of carbamide with different content of inhibiting substances. As a source of urease and strains of Nitrobacter and Nitrosomonas, sod-podzolic soil from the Educational and Experimental Soil-Ecological Center “Chashnikovo” of Lomonosov Moscow State University was used. Results. An improved, more rapid chromatographic method for the analysis of urea in water is proposed compared to the method described by the authors earlier. The inhibitory effect of the antibiotic tetracycline hydrochloride on the process of biotransformation of nitrite into nitrate caused by Nitrobacter strains has been shown. No significant effect of the antibiotic on the biotransformation of urea into ammonium and ammonium into nitrite under the action of Nitrosomonas strains has been established. Limitations. The studies were carried out on the model of water systems, which included an aqueous phase containing different concentrations of the antibiotic, soil suspension, urea, heavy metal ions at a temperature of t = 30 ○C, pH ~ 6.5. The influence of salt background, pH, and temperature on biotransformation has not been studied, which could, without changing the overall picture, reveal nuances in the kinetics of the main processes. Conclusion. Studies have shown the absence of the effect of the antibiotic tetracycline hydrochloride on the kinetics of the decomposition of urea to ammonium and carbon dioxide due to urease enzymatic activity; there is no effect of the antibiotic on the oxidation of ammonium to nitrites by Nitrosomonas strains. It was found: selective inhibitory effect of an antibiotic during the oxidation of nitrite to nitrate, due to Nitrobacter strains; inhibition of biotransformation processes by chromium ions along the entire chain of transformations from urea to nitrate; and the inhibitory effect of excess oxygen on the totality of biotransformation processes during air bubbling through the aqueous phase.

Current methodological guidelines for assessing the quality of soils in populated areas do not include ecotoxicological indices, thereby underestimate the potential danger of the negative impact of urban soils on the health of the population. Monitoring of soil quality is carried out according to established indices. Sanitary-parasitological and sanitary-bacteriological studies, of course, play a primary role in the establishment both of the category of soil contamination in populated areas, and basic physic-chemical parameters. The list of controlled elements contains heavy metals, benz (a) pyrene, arsenic and several others, but there are no whole classes of chemical compounds with a high level of public health hazard, such as polychlorinated biphenyls, in spite of the fact that the study of the distribution of this group of substances in the soil profile of Moscow is being included in modern scientific research work for a long time. Thus, the lack of data on the content of a number of key chemical toxicants in the soil can form a distorted final assessment of the quality of the studied soils. Ultimately, this can lead to a number of mistakes in management decisions for the improvement of the territories of Moscow and the replacement of soils with artificially created soil. One of the solutions to this problem may be the expansion of the list of physic-chemical indices in monitoring. Another one is the inclusion of ecotoxicological indices for conducting a comprehensive diagnosis of “health” of soils. Such an approach will make it possible to assess the soils more correctly, taking into account all the factors of soil formation in the territory of Moscow, including intensive multifactor anthropogenic impact on soils, which is difficult to estimate only with the help of physical and chemical methods. In the work results of own researches on an estimation of the biological activity of soils of Moscow of various functional zones are presented.