Introduction. The Black Sea Coast of the Caucasus is one of the most important recreational and tourist regions for Russia. In recent years, it has been subjected to a sharply increased anthropogenic load, due to an increase in the number of tourists, accompanied by an increase in traffic flows and, as a result, an increase in environmental pollution, including oil hydrocarbons. The risks of leakage of oil products during transportation and pumping are increasing. To predict and prevent dangerous consequences of pollution, it is necessary to determine the environmentally safe residual content of oil and oil products in the soil, based on the regional ecological and geochemical characteristics of soils. Materials and methods. Laboratory modelling of contamination with oil and petroleum products (fuel oil, gasoline, diesel fuel) of sod-carbonate typical soil was carried out. To simulate pollution, oil and petroleum products were added to soil samples including fuel oil, gasoline, diesel fuel in a weight concentration of 1% (low pollution), 5% (medium pollution) and 10% (high pollution) of the soil mass. The exposure period lasted 30 days. After the specified period, changes in biological parameters (enzyme activity, radish root length, number of soil bacteria) were determined. Based on the listed parameters, the integral indicator of the biological state IIBS of the soil was calculated . Results. Oil and oil products pollution negatively affected the biological properties of the studied soil. A significant decrease in enzymatic activity, the number of bacteria, and the length of plant roots was recorded. The range of toxicity of the studied substances on biological indicators of soils is as follows: oil > fuel oil > gasoline > diesel fuel. The study made it possible to determine the maximum level of residual content of oil and petroleum products (fuel oil, gasoline, diesel fuel) in the refinery. For oil, it is 0.27%, for gasoline – 0.40%, for fuel oil – 0.30%, for diesel fuel – 0.45%. Limitations. The proposed limit levels of residual oil and petroleum products (fuel oil, gasoline, diesel fuel) in soils are applicable primarily on the territory of the Black Sea coast of the Caucasus. Conclusion. The proposed limit levels of the residual content of oil and petroleum products (fuel oil, gasoline, diesel fuel) in the soils of the refinery area can be used by environmental, agricultural and scientific organizations

Relevance. Operation of solid municipal waste landfills leads to soil degradation and a decrease in its fertility. Studying the impact of heavy metals on the ecology of landfill soils and soils of adjacent territories is important, since the accumulation of high concentrations of heavy metals can lead to disruption of the ecological and agricultural functions of the soil. Aim. To assess the contamination of soils by heavy metals at the solid municipal waste landfill in the city of Rostov-on-Don. Objects. The studied soil samples taken from the center of the landfill were compared to soils of the adjacent territory at different distances and directions relative to the center of the landfill. Methods. Gross contents of heavy metals and metalloids (V, Cr, Co, Ni, Cu, Zn, As, Sr, Pb, Rb, Zr, Ba) were studied using the X-ray fluorescence method. The obtained values were used to calculate the pollution indices: background enrichment coefficient, individual unified pollution index, geoaccumulation index, pollution load index, Nemerov pollution index, potential ecological risk index, pollution protection index, pollution probability index, and general pollution degree index. These indicators were used to determine the pollution degree of the studied territories. Results: The excess of Cr, Ni, Cu, Zn, As and Pb according to the MAC at the landfill from the control was determined. A very high concentration of heavy metals and metalloids compared to the MAC and background was found in the center and close to the center of the landfill, indicating the anthropogenic contribution of these elements. The evaluation of the results showed that the pollution load index is more reliable for assessing the pollution of the landfill and the adjacent territory with heavy metals. When compared, the used indices and pollution coefficients formed the following series: pollution load index>general pollution degree index>Nemerov pollution index>pollution probability index>pollution protection index>potential ecological risk index=background enrichment coefficient. The adjacent territory of the landfill was polluted to a lesser extent. The applied indices and coefficients can be used in environmental assessment, as well as in monitoring and for preventing soil pollution with heavy metals and metalloids. For citation: Kucherova A.V., Minnikova T.V., Kolesnikov S.I., Sherstnev A.K. Assessment of heavy metal pollution of soils of a municipal solid waste landfill of the city of Rostov-on-Don. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 90–101. http://doi.org/10.18799/24131830/2026/8/5062

There are unique types and subtypes of soils on the Crimean Peninsula. The growing tourist load on the region requires an increase in the productivity of all industries, including oil refining. All of this increases risks of spills and leaks of oil and petroleum products during their transportation and pumping. There is a large gap in the field of regulation of soil pollution with petroleum products (gross content), which consists in the absence of maximum permissible concentrations in the regulatory framework of the Russian Federation. To predict the possible negative consequences of environmental pollution with oil and oil products, it is necessary to develop regional environmentally safe concentrations of oil and oil products that will take into account the local regional ecological and geochemical characteristics of soil types. The purpose of this study is to conduct laboratory modelling of environmentally safe oil concentrations in the soils of Crimea. Fuel oil contamination (1, 5, and 10

Remediation is an important area of oil-contaminated soil restoration in Russia, since oil refining industry is the major one for Russia and neighbouring countries, and the issues of environmentally effective and economically profitable remediation of oil contamination have not yet been solved. Soils under various economic uses have different surface areas and degrees of soil particles envelopment with oil due to the presence or absence of cultivation, the amount of precipitation and plant litter. The introduction of various substances for remediation into oil-contaminated soils of steppes (arable land), forests, and semi-deserts, considering their differences, gives different results. Biochar is coal obtained by pyrolysis at high temperatures and in the absence of oxygen. The uniqueness of this coal lies in the combination of biostimulating and adsorbing properties. The purpose of the study is to conduct an environmental assessment of biochar application for remediation of oil-contaminated soils under various economic uses. The article compares the environmental assessments of biochar application in oil-contaminated soils with different particle size fraction. The following indicators of soil bioactivity were determined: enzymes, indicators of initial growth and development intensity of radish, microbiological indicators. We found that the most informative bioindicator correlating with residual oil content is the total bacteria count, and the most sensitive ones are the roots length (ordinary chernozem and brown forest soil) and the shoots length (brown semi-desert soil). The use of biochar on arable land and in forest soil (ordinary chernozem and brown forest soil) is less environmentally efficient than in semi-desert soil (brown semi-desert soil). The study results can serve to develop measures and managerial and technical solutions for remediation of oil-contaminated soils under various economic uses.

The enzyme activity of oil-contaminated chernozem and soddy-podzolic soil is assessed for a set of 20 enzymes in the arable horizon of ordinary chernozem and the humus-accumulative horizon of soddy-podzolic soil under forest. Oil (1, 5, and 10

Under the influence of pollution by petroleum hydrocarbons, soils from different natural zones have different physical, chemical, and biological indicators of the soil condition. Biological indicators are the most sensitive to soil pollution and changes in the ecological state. Arid zone soils, compared to other types of soils, due to the soil formation conditions and the physical and biological properties, are very unstable to pollution by petroleum hydrocarbons. In this regard, it is important to standardize the content of petroleum hydrocarbons taking into account the response of enzyme activity and microbiological indicators, and an assessment of soil phytotoxicity. Such standards serve as parameters for the health of soils in a region when contaminated with oil and oil products. The aim of this study is to assess the environmental health standards of arid soils in southern Russia when contaminated with oil and oil products. It has been established that, with an increase in the concentration of oil and oil products, the biological indicators of soils are suppressed. The ecological standard for oil in brown semi-desert soil (0.1

The processes of extraction and enrichment of metal ores are accompanied by the formation of waste containing pollutants, including heavy metals. To reduce the impact on the environment, after decommissioning of the tailings dump, in which enterprises store waste, reclamation is carried out. In this study, the phytotoxic properties of the soil of the reclaimed tailings pond of the Urup mining and processing plant, using radish seeds (Raphanus sativus L. var. Radicula). As a result, it was found that the soils of the reclaimed tailing dump have a satisfactory level of phytotoxic indicators, from which it can be concluded that high-quality reclamation.

The effect of silver nanoparticles (AgNPs) in concentrations was evaluated 0.1; 0.5; 1; 5; 10; 50 and 100 mg/kg for the germination and root length of ordinary black earth radish 30 days after contamination. It was found that the degree of ecotoxic effect of AgNPs on the germination and length of radish roots is directly dependent on their dose in the soil. The content of AgNPs 1, 5, 10, 50, 100 mg/kg in ordinary chernozem caused a decrease in the germination of radish by 11, 13, 15, 18 and 38 % compared with the values in uncontaminated soil. Doses of AgNPs 0.5, 1, 5, 10, 50 and 100 mg/kg inhibited the length of radish roots by 19, 20, 25, 30, 37 and 43 % compared with the values obtained in uncontaminated soil. The radish root length index showed the greatest sensitivity to soil contamination by AgNPs compared to the germination index. The obtained results on the assessment of phytotoxicity of soils contaminated with AgNPs can be used for diagnostics and as an indicator of the ecological state of soils.

Enzymatic activity of soils is the most important diagnostic indicator of the ecological state of soils affected by various types of anthropogenic impact. The aim of the study was to evaluate the enzymatic activity of ordinary chernozem (Haplic Chernozem) contaminated with Ag, Bi, Te, and Tl. Ten enzymes (catalase, dehydrogenase, peroxidase, polyphenol oxidase, ascorbate oxidase, ferrireductase, protease, phosphatase, invertase, and urease) were analyzed. According to the degree of inhibition of enzymes, heavy metals formed the following sequence: Tl > Ag > Bi > Te. With an increase in the concentration of heavy metals, the toxic effect on the activity of enzymes increased. The oxidoreductases showed greater sensitivity to Ag, Bi, Te, and Tl contamination than hydrolases. Among oxidoreductases, the highest sensitivity was found for ferrireductase, and the lowest one for ascorbate oxidase. According to the activity of enzymes of the hydrolase class, invertase was the most sensitive, and urease was the least sensitive. When contaminated with Ag, Bi, and Te, invertase had the highest informative value, and when contaminated with Tl, urease and polyphenol oxidase were the most informative. Among the enzymes of the oxidoreductase class, the highest information value was found for peroxidase, and the lowest one for ascorbate oxidase. Among the enzymes of the hydrolase class, invertase was the most sensitive, and phosphatase was the least sensitive. The results of the study can be used to assess the ecological state of soils contaminated with Ag, Bi, Te and Tl.

The dynamics of phytotoxicity indicators (germination and length of radish roots) of ordinary chernozem when contaminated with silver nanoparticles was studied. In laboratory conditions, ordinary chernozem was contaminated with silver nanoparticles (1, 10 and 100 mg/kg) for 3, 10, 30, 90 and 180 days. It was found that the more silver nanoparticles were introduced into the soil, the greater the decrease in germination and length of radish roots. There was no restoration of germination and length of radish roots with an increase in the period from the moment of contamination. In this study, the maximum toxic period from the moment of contamination for each indicator was identified by its sensitivity to silver nanoparticles and informativeness. The maximum toxicity of silver nanoparticles in relation to the root length and germination of radishes was noted on the 10th and 30th days, respectively. The results can be used to assess the phytotoxicity of soils contaminated with silver nanoparticles.

The effect of contamination of ordinary black earth with platinum oxide (PtO2) on biological properties: root length and germination of radish, total number of bacteria, abundance of bacteria of the genus Azotobacter, activity of catalase and dehydrogenases have been studied. The concentrations studied were 0.01, 0.1, 1, 10 and 100 mg/kg in 10, 30 and 90 days after contamination. A stimulating effect (hormesis) of platinum oxide at a concentration of 0.01 mg/kg on the biological properties of ordinary black earth was recorded. It was found that in other cases, platinum oxide has a negative effect on the studied parameters, and exhibits the greatest toxicity after 30 days after contamination, followed by restoration of soil properties after 90 days. It was concluded that the most sensitive (highest degree of reduction) indicators to platinum oxide contamination were the total number of bacteria, germination and length of radish roots. Early diagnosis of the degree of soil contamination with platinum compounds is recommended in order to obtain a prompt assessment of the impact and prevent possible negative consequences.

Thallium ecotoxicity was assessed in laboratory model experiments by changing in microbiological, biochemical, and phytotoxic properties of soils in the South of Russia: ordinary chernozem (Haplic Chernozem (Loamic)), seropesok (Eutric Arenosol), and slightly unsaturated brown forest soil (Eutric Cambisol), differing in texture, pH, and organic matter content. There was usually a direct relationship between Tl concentration and the deterioration rate of the studied soil properties. The ecotoxicity of Tl nitrate was higher as compared to Tl oxide. The ecotoxic effect of Tl was the strongest for chernozem and seropesok within 10 days and for brown forest soil within 30 days after contamination. Restoration of biological soil properties was recorded on the 90th day. The resistance to Tl contamination was the greatest for ordinary chernozem and the smallest for seropesok. The results obtained indicate a high ecotoxicity of Tl.

The automotive industry is the main source of environmental pollution with platinum group metals, which increases the concentration of platinum in road dust, soil, and plants. This can lead to the achievement of toxic levels of this metal in the environment, and consequently, an imbalance of the ecosystem, a reduction in the microbial population, and a decrease in soil fertility. The effects of platinum on the activity of oxidoreductases of ordinary chernozem have been studied: the activity of catalase and dehydrogenase. Platinum was introduced into the soil in the form of chloride. Platinum concentrations were studied – 0.01; 0.1; 1; 10 and 100 mg/kg. The change in the indicators of ordinary chernozem was assessed 10, 30 and 90 days after contamination. The absence of a stimulating effect of platinum chloride on catalase activity, the effect of hormesis on the activity of dehydrogenases of ordinary chernozem has been established. The dependence of the degree of decrease in indicators on the concentration of the pollutant in the soil and the time from the moment of contamination is shown. The study shows the negative effect of even a small concentration (0.1 mg/kg) of platinum chloride on the enzymatic activity of the soil. Early diagnosis of the degree of soil contamination with platinum compounds can be successfully used to promptly assess their impact on soil condition and prevent possible negative consequences.

The ecotoxicity of Ag particles of different size has been assessed by microbiological, biochemical, and phytotoxic indicators for the upper layer (0–20 cm) of ordinary chernozem (Haplic Chernozem) in a laboratory model experiment. The effect has been studied of nano- (10 and 100 nm) and microparticles (1000 nm) of Ag at concentrations of 1, 10, and 100 mg/kg on the biological parameters of ordinary chernozem 30 days after contamination: the activity of catalase, dehydrogenases, ferrireductase, urease, peroxidase, polyphenol oxidase, invertase, phosphatase, the total number of bacteria, the abundance of bacteria of Azotobacter genus, the number of germinated seeds and the length of radish roots. It was found that the ecotoxicity of Ag particles depended on their size: in most cases, Ag particles 10 nm in size had a stronger ecotoxic effect on the biological parameters than particles 100 and 1000 nm in size. There were no significant differences in the ecotoxicity of 100 and 1000 nm Ag particles. The difference in the effects of Ag particles of different sizes increased with increasing Ag concentration in the soil: the higher the Ag concentration was in the soil (from 1 to 100 mg/kg), the more pronounced the difference was in ecotoxicity between 10 nm Ag particles and 100 and 1000 nm Ag particles. Phytotoxic indicators were more sensitive to contamination by Ag nanoparticles at all concentrations studied (1, 10 and 100 mg/kg); the total number of bacteria, invertase and phosphatase activity at 10 and 100 mg/kg; the abundance of bacteria of Azotobacter genus and the activity of dehydrogenases at 100 mg/kg. It is advisable to use these indicators in biodiagnostics of the ecotoxicity of Ag nanoparticles.

The ecotoxicity of Ag particles of different sizes was assessed by microbiological, biochemical and phytotoxic indicators of the upper layer (0-20 cm) of ordinary chernozem (Haplic Chernozem) in a laboratory model experiment. We studied the effect of nano- (10 and 100 nm) and microparticles (1000 nm) of Ag at concentrations of 1, 10 and 100 mg/kg on the biological parameters of ordinary chernozem 30 days after contamination: the activity of catalase, dehydrogenases, ferrireductase, urease, peroxidase, poliphenoloxidase, invertase, phosphatase, the total number of bacteria, the abundance of bacteria of the genus Azotobacter, the number of germinated seeds and the length of radish roots. It was found that the ecotoxicity of Ag particles depends on their size: in most cases, Ag particles 10 nm in size had a stronger ecotoxic effect on biological parameters than particles 100 and 1000 nm in size. There were no significant differences in the ecotoxicity of 100 and 1000 nm Ag particles. The difference in the effects of Ag particles of different sizes increased with increasing Ag concentration in the soil: the higher the Ag concentration in the soil (from 1 to 100 mg/kg), the more pronounced the difference in ecotoxicity between 10 nm Ag particles and 100 and 1000 nm Ag particles. Phytotoxic indicators are more sensitive to contamination by Ag nanoparticles at all concentrations studied (1, 10 and 100 mg/ kg); total number of bacteria, invertase and phosphatase activity – at 10 and 100 mg/kg; the abundance of bacteria of the genus Azotobacter and the activity of dehydrogenases – at 100 mg/kg. It is advisable to use these indicators in biodiagnostics of the ecotoxicity of Ag nanoparticles.

Pasture digression is one of the main factors of degradation and desertification of territories in the South of Russia. The impact of unsustainable grazing of agricultural animals on plant and soil cover has significant negative consequences, as a result of which the modern vegetation of the semi-desert of the Northern Caspian region has changed greatly over the decades and has taken on unfavorable dynamics. The object of the study was the soils of the Astrakhan region, subject to various stages of pasture digression. Phytoindication was carried out according to the indicators of germination and intensity of initial growth using a traditional test culture (Raphanus sativus L.). As a result of the study, no dependence was established between the indicators of germination and intensity of initial growth of radish on the stages of pasture digression. Soil phytotoxicity depended on soil properties, such as humus content, mobile phosphorus, soil solution reaction, and soil density.

Stable functioning of agricultural lands is impossible without maintaining soil fertility. However, there are often a lot of crop residues in the fields, which decompose for a long time and turn into available organic matter. To increase the rate of decomposition of crop residues of grain crops (wheat, barley and others), it is necessary to introduce biostimulants. Biostimulants are a variety of substances that stimulate the decomposition of organic substances and have a beneficial effect on the soil microbiota. The article examines the influence of Bacillus sp. on the processes of decomposition of crop residues of wheat both independently and together with biochar. The aim of the study was to evaluate the phytotoxicity of ordinary chernozem during the decomposition of crop residues of winter wheat under the influence of Bacillus sp. and biochar. To assess the ecological state of the soil, the following research methods were used: assessment of the rate of decomposition of cellulose (determination of cellulolytic activity), assessment of the ecological state of the soil (intensity of CO2 emissions, changes in the intensity of initial growth and development of winter barley (Hordeum vulgare L.)). Introduction of Bacillus sp. × 100 and the joint use of biochar and Bacillus sp. it stimulated the decomposition of cellulose up to 14–15% of the background content. Inoculation of Bacillus sp. on the biochar, it was effective already at the recommended dose both for the decomposition of the cellulose web and for restoring the ecological state of the soil, demonstrating a synergistic effect. The results obtained should be used in carrying out measures to increase soil fertility of agricultural lands and environmental monitoring of soil conditions.

An attempt has been made to assess the effectiveness of remediation of the tailing’s storage facility of a mining enterprise for the performance of ecosystem functions by a formed soil-like body in comparison with the background soil for this territory. To assess the biological properties of the soil-like body, the following were analyzed: the total number of bacteria, the abundance of bacteria of the genus Azotobacter, the activity of soil catalases and dehydrogenases, germination, and length of radish roots. An integral indicator of the state of the soil-like body was calculated for a comprehensive assessment of the effectiveness of tailings pond reclamation. It was found that the soil-like body of the reclaimed tailings dump performs its ecosystem functions as fully as the background mountain meadow chernozem soil for this territory. It is concluded that the reclamation works were carried out effectively with the restoration of the ecosystem.

Relevance. Soil pollution with oil has a significant impact on soil fertility and productivity when growing crops. During soil remediation, insufficient attention is paid to soil phytotoxicity assessment in terms of the intensity of the initial growth and development of plants. The results of the study of ordinary chernozem phytotoxicity evaluation on the example of winter barley (Hordeum vulgare L.) after remediation with biochar and a bacterial preparation, containing strains of Bacillus & Paenibacillus, are presented. Aim. To evaluate ordinary chernozem integral phytotoxicity after remediation with biochar and a bacterial preparation, containing strains of Bacillus and Paenibacillus. Objects. Ordinary heavy loamy chernozem, under model conditions, which 5% of the soil mass are oil-contaminated. For soil remediation from oil pollution, biochar and a bacterial preparation with Bacillus & Paenibacillus strains were applied in various combinations: independent application of ameliorants, joint application, inoculation of bacterial preparation with Bacillus & Paenibacillus on biochar. The period of soil incubation with biochar and of bacterial preparation with Bacillus & Paenibacillus has a duration of 30 days. Methods. The residual oil content was determined by the method of extraction with carbon tetrachloride with detection on an infrared analyzer. Soil phytotoxicity after remediation was assessed by indicators of the intensity of initial growth and development of winter barley (Hordeum vulgare L.): germination, germination rate, germination energy, germination friendliness, shoot length, root length, shoot phytomass, root phytomass. As a result of determining these indicators, a complex integral indicator of soil phytotoxicity (IIPht) was calculated. Results. The combined use of biochar with of bacterial preparation with Bacillus & Paenibacillus in oil-contaminated soil leads to the most effective reduction in oil content than when self-introduced and inoculated with of bacterial preparation with Bacillus & Paenibacillus on biochar at the recommended and 100-fold dose, the efficiency is 33 and 58%, respectively. Based on the analysis of phytotoxicity, the highest sensitivity of indicators of barley initial growth intensity was established: germination, friendliness and germination rate. With the independent application of biochar and of bacterial preparation with Bacillus & Paenibacillus, the most informative indicators are shoot phytomass, germination and germination rate; with the combined application of biochar and of bacterial preparation with Bacillus & Paenibacillus, germination energy, shoot length and shoot phytomass; with inoculation of of bacterial preparation with Bacillus & Paenibacillus on a biochar, root length, phytomass of shoots and roots. The study of the phytotoxicity of oil-contaminated Haplic Chernozem after remediation made it possible to establish the ecological efficiency and expediency of using only biochar and biochar inoculated with of bacterial preparation with Bacillus & Paenibacillus.

The study of the effect of lithium pollution on invertase activity in Haplic Chernozem, Eutric Cambisol and Eutric Arenosol was carried out. Lithium was introduced in the form of chloride and hydroxide at concentrations of 15, 100 and 500 mg/kg. The control was uncontaminated soil with a natural background content of the element. Incubation was carried out for 10 days. As a result of the study of the effect of lithium pollution on invertase activity in soils of different buffering, it was found that contamination of the studied soils with lithium compounds leads to a decrease in invertase activity. The change in enzymatic activity depended on the concentration of the element in the soil. When low concentrations of lithium compounds are introduced, the effect of hormesis is recorded. Haplic Chernozem and Eutric Cambisol showed the greatest resistance to lithium contamination, while Eutric Arenosol showed the least resistance.