Moscow University Soil Studies Bulletin. 2026. 1.

The review provides a brief description of ecotoxicodynamics as a section of environmental toxicology including the subject of research, theoretical underpinnings and relevant studies. It has been shown that the development of ecotoxicodynamic studies at the present stage associated with the assessment of environmental quality and risk, establishing a database for ecological regulation, analysis of the processes of degradation and self-restoration of natural ecosystems.Particular attention is paid to the analysis of achieved successes in the study of the action of ecotoxicants on the example of their new types (nanoparticles, microplastics, harmaceuticals, food additives). The potential for them to exhibit toxic effects from genetic to ecosystem level including with real existing content has been demonstrated. The effects in organisms manifest as geno- and cytotoxicity and are reflected in violations of the reproductive, immune, enzymatic and digestive systems, behavioral reactions, decrease the rate of growth and development of organisms, the rate of photosynthesis, etc. In ecosystems the consequences of these effects may be а decline in the number and extinction of sensitive species, negative changes in interspecies relationships, loss of biodiversity and productivity of the biocenosis. Gaps in the study of new ecotoxicants are shown, to eliminate them promising research directions have been proposed in particular: investigations оn sublethal effects under real ecosystem loads, assessment of the possibility of developing chronic and delayed effects, detection of the influence of ecotoxicant properties and environmental factors оn toxic effects as well as consideration of combined effects of several ecotoxicants and products of their transformation. The problematic aspects in the study of ecotoxicants were noted by authors of the reviewed research papers. They are (1) the differences in the "scenario" of experiments among different authors, that make comparative assessment difficult to identify general patterns of possible ecotoxicant action in the environment, (2) application model experiments with standard media, that do not reflect real natural conditions and reduce the practical significance of the results obtained.

The concept of "soil health" has gained significant popularity in scientific literature as a key framework for ensuring ecosystem sustainability. However, the meaning of this term remains ambiguous, and universal assessment criteria are lacking. The aim of this article is to analyze contemporary definitions of "soil health" proposed by domestic and international soil scientists and to review methods for its evaluation. Emphasis is placed on indicators and monitoring systems that claim a degree of universality in diagnosing soil health. According to the European conceptual framework, the term "soil health" should reflect the broad influence of soil cover on ecosystems, including traditionally recognized aspects such as crop productivity, water and air quality regulation, climate regulation, biodiversity conservation, and the provision of social and cultural ecosystem services. In 2021, the European Union adopted a soil development strategy aimed at achieving healthy conditions for all EU soils by 2050. The term "soil health" is expected to be formalized with the adoption of the Soil Monitoring and Resilience Law, which will establish soil health standards. Researchers from Cornell University (USA) have proposed a similar methodology for comprehensive soil health assessment, termed CASH (Comprehensive Assessment of Soil Health). Both systems – CASH and the Soil Monitoring and Resilience Law – are examined in detail in the article. Additionally, the search for a universal soil health indicator continues; the article discusses metrics such as organic matter content, the soil organic carbon-to-clay ratio (SOC:Clay), and its alternatives (Observed/Typical SOC ratio, SOC/SOCexp). A literature review reveals that the rationale for introducing the term "soil health" remains questionable. In practice, "soil health" is almost universally interpreted as a combination of physical and chemical properties that potentially influence soil fertility. Moreover, practices aimed at restoring "soil health" primarily focus on maintaining agronomic soil properties. In this regard, the indicators and methods for assessing "soil health" differ little from those used to evaluate "soil quality". Russian studies tend to explore fundamental aspects of soil system resilience, emphasizing the biological origins and biodynamic essence of soil. Proposed assessment methods are also based on microbiological indicators: thermodynamic characterization of microbial systems, the heterotrophic parameter of soil health, the self-sufficiency parameter for biophilic elements, phytosanitary soil status indicators, and enzymatic activity. The reviewed indicators and monitoring systems demonstrate potential for comprehensive soil diagnostics. However, their universality is limited by variability in soil-climatic conditions and land-use types.

The number of soil bacteria is an indicator of the condition and health of soils under chemical contamination. However, the native abundance of soil bacteria in the soils of different climatic zones varies significantly. Depending on the soil-forming factors, the number of bacteria in the soils of different climatic zones will vary. To assess changes in the number of soil bacteria, soil contamination of different climatic zones (semi-deserts, steppes and forests) with lead (Pb) in the following concentrations was modeled: 100, 1000 and 10,000 mg Pb×kg^–1 of soil. It was found that at a maximum concentration of 10,000 mg Pb×kg^–1 of soil, the number of soil bacteria in different types of soils was inhibited by 46–92% compared with the control. With an increase in Pb concentration, the number of soil bacteria decreased in semi-desert soils: from 1.61 billion×g^–1 (typical salt marsh) to 0.89 billion×g (chestnut and brown semi-desert soils); in steppe soils: from 4.50 billion×g^–1 (podzolic chernozem) to 0.80 billion×g^–1 (common chernozem); in forest soils: from 8.00 billion×g^–1 (dark gray forest soil) to 1.90 billion×g^–1 (sod-podzolic soil). The soils of the forest climate zone were found to be the most resistant to Pb pollution, while the soils of the steppe climate zone were the least resistant. Among semi—desert soils, the most sensitive are typical salt marshes, among steppe soils — podzolic chernozems, forest soils - sod-podzolic illuvial-ferruginous soils. A comparison of the number of soil bacteria in three climatic zones of Russia with lead contamination has been carried out. The results of the study can be used to indicate the ecological status and health of soils contaminated with heavy metals.

The results of a vegetation experiment on the humus horizon of sod-podzolic sandy loam soil (Albic Retisol) are presented. Until 1990, sewage sludge was added to the soil, which resulted in the formation of complex polyelement pollution with heavy metals, and even after 30 years the soils remained contaminated.

During this period the phosphorus content decreased by 4 times, potassium by 1.5, and the organic carbon content by 1.6 times. The content of heavy metals also decreased significantly compared to the initial level: Cd by 5 times, Zn and Cu by 1.5 times, Pb by 1.4 times. Vegetation experiments using zeolite clinoptilolite, zeolite ZION and the humic preparation “Vibrostand” showed the possibility of reducing the content of heavy metals using ameliorants in Vicia sp. plants and, to a smaller extent, in Avena sp. A study of the effect of ameliorants on the content of heavy metals in plants grown on soils fertilized with sewage sludge 30 years ago showed that their application changes the content of heavy metals and their distribution within plant organs. Moreover, Vicia sp. plants accumulate significantly less heavy metals than Avena sp., which can be used on soils taking into account their pollution levels. The ameliorants used in the experiments reduce the content of Cd, Zn, Cu and Ni in Vicia sp. plants by 40–60%, but the standard content of heavy metals in plants could not be achieved with such a high level of soil pollution. For Avena sp. plants, the ameliorants were less effective.

The article presents a comparative analysis of the spatial structure of technogenic impacts on soil cover under conditions of localized (point-source) and diffuse (area-wide) pollution. The study focuses on the territories of Sverdlovsk and Tula regions, which are contrasting in terms of land use and the nature of anthropogenic transformation. The former is characterized by an industrial landscape dominated by stationary emission sources, while the latter represents an agro-industrial region with a developed background level of pollution formed by the combined effects of agricultural activity, dispersed emissions, and long-term radiological impacts. Based on data on heavy metal (Cu, Pb, Cd, Zn) concentrations in soils and the application of remote sensing (NDVI) and geoinformation analysis methods, a functional zoning approach is proposed. This approach allows for the differentiation of land areas by the intensity of technogenic pressure and the degree of ecological transformation. The methodological framework includes key concepts such as the environmentally permissible background (EPB), the anthropogenically modified background (AMB), and the point of no return (PNR), the latter being interpreted as a critical threshold beyond which ecosystem degradation becomes irreversible and bioproductivity steadily declines. The zoning model comprises sanitary protection zones (SPZ), ecological responsibility zones (ERZ), and post-contamination zones (PCZ), each of which possesses specific functional and regulatory attributes. The paper substantiates the need to move away from universal maximum permissible concentrations (MPCs) toward regionally adapted background-based benchmarks derived from empirical observations. The proposed methodology was tested across representative sites with varying degrees and types of anthropogenic influence and demonstrated high sensitivity to the interplay between physicochemical and landscape factors. The findings offer a more substantiated basis for the design of sanitary and environmental protection measures, refinement of soil quality standards, and formulation of sustainable land-use strategies. The developed approach can be applied in the practice of environmental and cadastral services, regional spatial planning, industrial environmental assessment, and soil and environmental monitoring systems at both regional and municipal levels.

The paper presents the results of a study of the impact of rail transport on the forest ecosystems of the Valdai National Park. Previously, comprehensive scientific studies of the impact of railways on specially protected natural areas were not conducted. The location of the park in an important transport corridor affects the ecological state of natural systems. Unlike most territories through which railway communication is carried out, the site chosen for research allows assessing the environmental impact of railway transport in the absence of other anthropogenic sources of impact. The gross content of heavy metals and metalloids in the soils of the section adjacent to the railway and the background territories of the park has been determined. Analysis of the gross content of heavy metals in soil samples taken in 5 m increments from the railway embankment showed an excess of the maximum permissible concentrations (MPC) of some elements at a distance of 30 meters from the track. The maximum permissible concentration is observed in manganese, nickel, copper, zinc, arsenic, cadmium and lead. The embankment has a high content of elements such as strontium, barium, copper, and iron. The calculation of quantitative indicators of soil contamination showed that a strong level of contamination is observed at the embankment and at a distance of 25 and 30 m from it. A correlation analysis was conducted, and a model for the distribution of heavy metals and metalloids was presented. An important result of the study was the identification of the role of natural plant communities in the migration and accumulation of pollutants. It was found that the gray alder, located 30 meters away from the embankment, acts as the first mechanical barrier that limits the spread of heavy metals. The second barrier is formed by the sour spruce, which grows 43 meters away from the railway track. These natural filters help to reduce the intensity of the migration of pollutants into the depths of the forest. Exceeding the permissible limits for manganese, nickel, copper, zinc, and cadmium in soils is associated with the wear and tear of railway transport facilities (wheels, rails, and wagons). Arsenic is a component of diesel particulate matter. The increased copper content is associated with railway lubrication, and barium and strontium indicate the use of carbonate crushed stone on railway embankments. The results obtained contribute to understanding the mechanisms of the spread of pollutants from linear transport facilities, are of practical importance for the development of environmental protection measures, and can be used to normalize the impact of rail transport within specially protected natural areas affected by railway.

The influence of recreation on carbon (C) and nitrogen (N) reserves in the litter and upper mineral horizons of soils of larch stands in Izmailovsky Park, Moscow, was studied. The objects of study - a recreationally disturbed larch forest (third stage of digression) and a control larch forest (first stage of digression). The following indicators were determined: carbon and nitrogen reserves in all litter subhorizons, as well as in different fractions of subhorizon L, reserves of total and labile C and N in the 0–10 cm layer of the mineral part of the soil profile. It has been shown that under recreational load, the accumulative role of litter decreases compared to the control, and the difference in the reserves of C and N in litter by the components of tesserae is leveled out. The decrease in the reserves of C and N in litter is determined by the decrease in the total reserves of the litter itself. Significant losses of C and N from the humified and fermentative litter subhorizons due to recreation were detected. Maximum C and N losses from the litter correspond to the near-trunk spaces. Within the L-F-H litter profile, maximum losses are observed in the humified subhorizon in the sub- and inter-crown spaces. Under recreational loads corresponding to the third stage of soil degradation, no changes in C and N accumulation in the upper mineral soil horizon were recorded.

The article presents the results of a study on the dynamics of the height, reserves, and chemical composition of snow cover within the megapolis (Moscow) and conditionally background territories of the Solnechnogorsk district of the Moscow region (Educational and experimental soil and ecological center of Lomonosov Moscow State University “Chashnikovo”) for the winter-spring period of 2023–2024.

The study objects included: the drainage divide area of the Klyazma River in conditionally background conditions and two types of soil lysimeters from the Faculty of Soil Science of the Lomonosov Moscow State University located within Moscow. The first type of lysimeters was characterized by various soil cultivation methods under continuous operation in meadow mown phytocenosis conditions. The second type of bulk lysimeters were situated under different land use types (bare fallow, fallow land, overgrowing fallow land, spruce plantations, mixed, and broad-leaved forests) formed on a uniform mineral matrix represented by cover loam.

The dynamics of snow cover exhibited similar patterns in both natural and city conditions: maximum snow reserves occurred in February, followed by a decline in spring. Minimum snow reserves were observed in lysimeter areas with spruce plantations, while maximum reserves were recorded in treeless areas, including grass fallow and lysimeter plots under various soil cultivation conditions. In urban environments, significantly higher concentrations of certain alkali and alkaline earth elements (sodium, calcium, strontium), as well as zinc and copper, were detected. The concentrations of the most mobile anions, particularly chlorides, in the snow water of the megapolis exceeded those in natural conditions by 2–3 times. This is consistent with the higher pH and electrical conductivity values for snow water in urban settings.

The type of phytocenosis played a key influence in the spatial distribution of snow and its components. Coniferous and mixed forests retained more snow, which reduced the migration of lysimetric waters, whereas broader-leaved and open areas experienced more intense snow accumulation and vertical water migration.

The dependence of soil bulk density on penetration resistance, moisture content, soil organic carbon content and particle size distribution was investigated for Retisols of the Educational and Experimental Soil and Ecological Center of Lomonosov Moscow State University “Chashnikovo”. Penetration resistance was measured with a penetrologger at six key sites with different land-use types, in areas in front of three soil profiles. Soil samples for bulk density were taken from the same profiles using 100 cm³ cutting rings. The samples were subsequently analyzed for moisture content, organic carbon (by the Tyurin method), and particle-size distribution using a laser diffraction analyzer. Within the study, 24 regression models for predicting soil bulk density were developed and analyzed. The quality of these models varied; the coefficients of determination (R²) ranged from 0.23 to 0.89 and the root mean square error (RMSE) from 0.07 to 0.18 g×cm^–3. Based on the modelling results, the greatest contribution to predicting bulk density was made by organic carbon content, depth and penetration resistance, in descending order. Adding specific particle-size fractions to the model is more informative than using the principal components of particle-size fractions as predictors. The use of specific particle-size fractions is more informative than using principal components as predictors. In many models, field soil moisture proved to be an insignificant predictor for bulk density. Given the labour-intensive nature of determining a full set of predictors, models with a reduced set of predictors were proposed: 1) depth and penetration resistance; 2) organic carbon content and penetration resistance; and 3) organic carbon content alone. The data from the first of these models are automatically collected during the use of the penetrometer, making it convenient for monitoring surveys. The method has important limitations relating to the particle size distribution of soils and how this is determined. For example, it is impossible to take a top-down measurement of penetration resistance with a penetrologger in the presence of large boulders in the soil, as the measuring tool hits them and cannot be pushed into the underlying horizons. The use of regression equations in which particle-size distribution is determined by a method other than laser diffraction is incorrect. The choice of which particle-size fraction to use as a predictor should be based on a correlation analysis for each territory in question.

It is shown that time has always been considered by soil scientists as a “special” factor of soil formation — the form of the soil's existence as a material body. Soil formation processes are almost always nonlinear in time and cyclical (often this cyclicity is interrupted by the flow of soil formation). The soil, as a natural body, on the one hand, obeys the internal laws of self-development (in particular, the erasure of “lithological memory” and the development of “soil memory” during one stage /spurt of evolution), on the other hand, is subject to various (including anthropogenic) factors of influence, theoretically, all types of nonlinear dynamic behaviors - chaos, multistability, amplitude decay, solitons. The change in soil condition over time within one stage of their multi-stage evolution is usually described by a logistic equation. Differentiating the state function S from time t allows us to get an idea of the rate dS/dt and acceleration d2S/dt2 of soil formation processes. The inflection points on the soil condition graph become the extreme points on the graphs of derivatives of soil formation. It is noted that dissipative processes prevail in the “first half”, and antidissipative processes prevail in the “second half” of each stage of evolution. The predominance of dissipative processes over antidissipative ones is not homogeneous at all: at first it occurs at the start of the acceleration of soil formation, and then — at the stage of decrease.