Vol 23, No 2 (2023)

The number of nitro compounds of the anthropogenic origin in the general nitrogen cycle is steadily increasing, which leads to an increase in nitrates in products and increases the nitrate-nitrite load on the human body. The aim of the study was to determine the amount of nitrates in raw vegetables and their processed products. Vegetables with high (beetroot, cilantro, radish, green onion), medium (zucchini, carrot, cucumber) and low nitrate content (potato, tomato, onion) have been selected as the objects of the study. For the qualitative determination of nitrates the reactions with diphenylamine have been carried out. For quantitative determination, the ionometric determination of the pH-meterionomer Ecotest 2000 has been carried out using an ion-selective electrode ECOM-NO3. In the course of the study, it has been found out that the vegetables entering the Magnit retail chain do not exceed the MPC in terms of nitrate content, with the exception of the radish and zucchini. When cooking in a microwave oven the amount of nitrates increases dramatically. When cooking vegetables «until ready», the amount of nitrates in vegetables decreases, but their amount in broths increases. With prolonged heat treatment the amount of nitrates increases both in vegetables and in the broth. When freezing and defrosting vegetables in a closed container, a decrease in nitrates is observed, and when defrosting in an open container, the level of nitrates increases sharply. Thus it is recommended not to use a microwave oven during the cooking process. During boiling fi rst drain the water, then pour in new one and boil until ready. Ready-made vegetables should not be left in the broth due to the reverse adsorption of ions. Vegetables should be defrosted in a closed container.

The weakening of the manmade load on the environment has become a global goal of humanity. The accumulation of toxic substances in effl uents can increase the acceleration of pollution of the planet’s watersheds, resulting in biota pollution. To solve this problem, it is necessary to create photocatalysts that cause self-excitation under the ignition of light. Also, important parameters of photocatalysts are simple synthesis and low cost. This article demonstrates a one-step approach to the synthesis of carbon nanostructures (CNS) with photocatalytic activity. For this purpose, the “green chemistry ” method is used – hydrothermal treatment of various polysaccharides (sodium dextran sulfate (SDS), starch, pectin), which opens up the possibility of recycling products. A comprehensive study of the properties of the synthesized CNS has been carried out. To study the optical properties of CNS, absorption and luminescence spectroscopy, and IR spectroscopy, have been used. The CNS obtained have been successfully used in the processes of photocatalytic destruction of a model of the organic dye tartrazine, which is widely used in the fi ber and textile industries. The eff ect of lyophilization on the photocatalytic properties of СNS has been studied, and cytotoxicity has been evaluated.

One of the modern approaches to solving environmental problems of accumulation and deposition of production and consumption waste is the implementation of “green economy” and “closed cycle” economy models. This approach makes it possible to increase the resource utilization rate and reduce the negative impact on the environment. The study of the possibility of joint disposal of waste from various industries, for example agricultural and industrial waste, is promising in this area. The analysis of the current state of work in this direction is carried out, using the example of the possibilities of joint utilization of phosphogypsum and organic waste. A new eco-friendly approach to the utilization of a large-tonnage secondary material resource – phosphogypsum together with organic waste is proposed. Phosphogypsum acts as a matrix for the production of complex organomineral fertilizers and meliorants of complex composition, the introduction of the organic component of fertilizers is carried out in the fi nished and neutralized liquid phase. Agricultural waste, municipal waste, s ewage sludge can be the raw materials for the organic component. The eff ectiveness of the complex organomineral fertilizer an d meliorant based on phosphogypsum (90% by weight) and the liquid fertilizer “Rabiol” with the inclusion of a highly selective sorbent based on molecular imprinted polymers to imazamox, a resistant herbicide of the imidazolinone class, is shown.

Graft copolymers of polysaccharides with acrylic monomers combine biodegradability, biocompatibility, the environmental friendliness of natural polymers and the increased thermal stability, chemical and mechanical resistance of synthetic polymers. This paper describes our search and analysis of the literature in English for 2002–2022 devoted to the graft polymerization of acrylamide, acrylic acid and 2-acrylamido2-methylpropanesulfonic acid onto xanthan and glucomannan macromolecular chains. It has been found that the synthesis of grafted copolymer chains proceeds by a radical polymerization mechanism using thermal homolytic decomposition of the initiator or microwave irradiation, or radiation initiation and frontal polymerization in some cases. Depending on the method of the reaction, the synthesis time of a graft copolymer varies from several minutes to several hours. The infl uence of the synthesis conditions and parameters on the monomer conversion, structure and properties of the resulting polymer has been considered. It has been found that decreasing the polysaccharide/monomer ratio and increasing the initiator concentration raise the effi ciency and degree of grafting. Several methods for characterization of graft copolymers are discussed, including: IR spectroscopy to analyze the chemical structure of a sample, scanning electron microscopy to characterize structure, supramolecular ordering and porosity, diff erential thermal analysis to evaluate thermal eff ects and thermal stability. The eff ect of the synthesis conditions and the pH of the sorption medium on the water absorption and sorption capacity of this class of graft copolymers are discussed. The broad potential of graft copolymers for repeated cycles of absorption and release of liquid medium without loss of functional properties has been found. This opens prospects for the use of graft copolymers of xanthan and glucomannan with acrylic monomers as materials for water purifi cation from metal ions and cationic dyes, targeted delivery and prolonged action of drugs and wound coatings for wound treatment.

This abstract presents the results of screening for allelopathic activity of three pairs “aboriginal-exotic” of comparison species of herbs, including invasive species, systematically related at the level of the genus. It was shown that a 1% leaf extract of Solidago virgaurea and S. canadensis, Pulmonaria obscura and P. saccharata, Veronica serpyllifolia and V. fi liformis had a similar or equal inhibitory eff ect on the germination and growth of test-plant roots in biotests owing to its chemosystematic correlation. Extracts of Solidago and Pulmonaria species slowed down the rate of germination and root growth by 1.5–2 times lower than the control. In the Salidago sp. experiment options the dynamics of the processes developed according to the type of stress-reaction. The absolute rate of root growth at the exponential stage diff ered twice in the Solidago sp. options: 16.8±0.43 and 8.99±0.23 mm/day in native and exotic specie, respectively. The total germination was close to or equal to the control level. In a comparison pair Pulmonaria sp. germination decreased by 58.66 and 43.5%. V. fi liformis extract inhibited germination by 24.4% more than the native species. Extracts 0.05% extracts of Solidago sp. had no eff ect, P. saccharata and V. fi liformis extracts caused the eff ects of hormesis. P. saccharate option produced an – acceleration of the absolute and relative root growth rate of the test-plants by two times, exceeding the total length of the roots by half compared to the control and the native species. In the V. fi liformis option, the rates of germination and root growth was inhibited by 24.7 and 50.2% of the values of the paired species, respectively. The comparative method increases the level of analysis of bioassay data, allows for a deeper study of the specifi cs of test-plants reactions, and allows the evaluation of the modes of action of allelochemics.

. This study is dedicated to the nest placement peculiarities of four species of the Corvidae family: the Jackdaw, Rook, Hooded Crow, and Eurasian Magpie – in the urbanized environmental components on the territory of the Kirovsky district of Saratov. The following methods were used in the work: route and areal accounting, cartographic modelling, plotting isolines based on cartographic data, assessing the reliability of diff erences in the number of corvid nests using Pearson’s chi-squared test, determining the rate of urbanization of various areas of the model area based on the method used by E. L. Lykov, assessing the dependence of the number of nests on the rate of the territory urbanization using Spearman’s correlation coeffi cient. The distribution of 652 nests according to the biotopes was analyzed, the assessment of the corvid nesting density in various urban environmental habitats was carried out. The nest placement density reaches its maximum in the areas with abundant green places, a large number of nesting sites, both of natural and anthropogenic origin and low rate of human disturbance, being in the areas with low-rise buildings, in the forest belts, in the natural park “ Kumysnaya polyana”and in the old Voskresenskoe cemetery. The Jackdaw and the Rook are the most selective for breeding sites species, their nests being located in human buildings and on closely placed tall trees. The Hooded Crow nests most evenly and successfully occupied the habitats of Saratov. The Magpie’s nesting areas are more associated to large groups of woody vegetation, the highest density of its nest placement was observed in the natural and natural-anthropogenic components of the urban environment. The negative relation between the quantity of nests of the two species – the Hooded Crow and the Magpie – and the rate of the territory urbanization was revealed. The nesting of the Jackdaw and the Rook are aff ected mostly not by the urbanization rate, but the availability of breeding sites.