This study examines the effects of oil contamination on three soil types—podzolic, sod-gley, and alluvial—in Western Siberia’s middle taiga, assessing key physical and chemical properties and the influence of the surfactant Modified Syntherol (MS) on oil degradation. In controlled laboratory experiments, oil was introduced at 50, 100, and 150 g/kg concentrations. Results indicate a substantial increase in soil pH, most notably in podzolic soils, alongside a significant decline in cation exchange capacity (CEC). For example, CEC in podzolic soils dropped five-fold at higher contamination levels, reflecting a reduced ability to retain essential nutrients. The water retention capacity decreased in all soil types, with the most pronounced decline observed in alluvial soils’ capillary moisture levels. MS application did not accelerate oil degradation; even after 35 days, natural decomposition rates in untreated soils remained low (0.02–0.4%), underscoring the persistence of oil contaminants. Notably, podzolic soils showed the highest susceptibility to oil contamination due to their acidic and low-organic nature, in contrast to sod-gley and alluvial soils, which demonstrated moderate resilience. These findings highlight the need for soil-specific remediation approaches, as general methods may be ineffective for soils with differing vulnerabilities and recovery capacities. This research provides essential insights for developing effective, tailored strategies to address the environmental challenges of oil pollution, advancing sustainable soil management practices for sensitive taiga ecosystems.

Surfactant-enhanced remediation is a promising approach for treating petroleum-contaminated soils, particularly in areas where conventional methods are limited by environmental constraints. This study investigates the application of Tween 80, a non-ionic surfactant, for remediating diesel-contaminated Albic Podzolic soils typical of boreal regions. Laboratory experiments were conducted over 90 days, using two surfactant concentrations (3.0 × 10⁻⁴ and 1.5 × 10⁻⁴ mol L⁻¹) and two temperature regimes (22–24 °C and 2–3 °C), simulating seasonal variability in cold-climate contaminated sites. The lower Tween 80 concentration—below the critical micelle concentration—proved more effective, achieving up to 21% total petroleum hydrocarbon (TPH) reduction at ambient temperature and 17% under refrigerated conditions. Treated soils also exhibited pH neutralization, indicating improved chemical stability. Acute toxicity bioassays (Vibrio fischeri and Ceriodaphnia affinis) confirmed the environmental safety of the applied concentrations (≤0.3 mol L⁻¹). These results support the practical use of Tween 80 in the remediation of petroleum-contaminated soils under boreal constraints, providing transferable data for designing safe and efficient field-scale treatment strategies. This work also offers insights that are relevant to remediation policies in cold climates and to the adaptation of surfactant-assisted technologies for diverse field conditions.

Chemical and biological approaches are widely applied to assess petroleum hydrocarbon contamination in soils; however, their results are often difficult to compare due to the use of fundamentally different extraction media. Chemical analytical methods typically rely on non-polar organic solvents, whereas biological toxicity assessments are based on aqueous soil extracts, reflecting water-soluble fractions of contaminants. This methodological discrepancy complicates the integrated evaluation of soil contamination and the assessment of remediation effectiveness. This study proposes an FTIR-based approach for assessing petroleum hydrocarbon contamination in sandy podzolic soil based on extraction with aqueous dimethyl sulfoxide (DMSO). The proposed method aims to reduce the methodological gap between classical chemical monitoring and aqueous-based biological assessment frameworks. The extraction performance of distilled water and aqueous DMSO solutions with different concentrations was evaluated using model soil samples artificially contaminated with crude oil. Crude oil was used as a multicomponent contaminant, whereas “petroleum hydrocarbons” refers to the operationally defined hydrocarbon fraction extracted from the soil–oil system and detected by FTIR in the C–H stretching region. Hydrocarbon extraction efficiency was assessed based on characteristic C–H stretching absorption bands in the 2800–3100 cm⁻¹ infrared region. Distilled water exhibited limited extraction capacity and rapidly reached saturation, resulting in weak and concentration-independent absorption responses. In contrast, aqueous DMSO increased the apparent solubility of hydrocarbons and yielded reproducible, concentration-dependent spectral responses. A 75% (v/v) aqueous DMSO solution was selected as a practical compromise extraction medium, increasing analytical sensitivity while remaining more compatible with aqueous conditions than conventional non-polar organic solvents. The proposed method provides a lower-hazard and methodologically coherent extraction approach for FTIR-based chemical monitoring of petroleum-contaminated soils and may facilitate improved comparability between chemical measurements and aqueous-based biological assessment approaches in integrated soil contamination and remediation studies.

Petroleum contamination of soils remains a significant environmental problem in boreal regions, where low temperatures constrain natural attenuation processes and complicate bioremediation. Nitrogen biostimulation is widely used to enhance petroleum hydrocarbon degradation; however, the combined effects of temperature regime, nitrogen form, contamination level, and nitrogen dosage remain insufficiently resolved for sandy podzolic soils of northern regions. This study investigated nitrogen-assisted biostimulation of petroleum-contaminated sandy podzolic soil collected in the Khanty–Mansi Autonomous Okrug (Western Siberia, Russia) using a factorial experimental design. Soil samples were artificially contaminated with crude oil at concentrations of 25, 50, and 100 g kg⁻¹ and incubated under warm and cold temperature regimes. Two nitrogen sources, urea and ammonium nitrate, were applied at several dosages. Changes in residual petroleum hydrocarbon content were monitored together with the abundance of culturable microorganisms under the applied cultivation conditions at the intermediate contamination level on day 60. Nitrogen supplementation enhanced petroleum hydrocarbon removal relative to the untreated control, but the magnitude of the effect depended substantially on temperature, nitrogen form, and contamination level. Under the tested conditions, ammonium nitrate was generally associated with stronger hydrocarbon removal than urea, particularly at the intermediate contamination level (50 g kg⁻¹). The results indicate that the response to nitrogen biostimulation in sandy boreal soils is controlled by interacting experimental factors rather than by nitrogen addition alone. These findings improve the positioning of nutrient-assisted remediation in cold-region soils and provide a basis for future mechanistic and field-scale studies.

Diesel fuel is among the most persistent petroleum-derived pollutants in soils, posing long-term ecological and toxicological risks, especially in cold-climate regions where natural degradation is limited. Reliable assessment of diesel-contaminated soils remains difficult because conventional solvent-based analyses are incompatible with bioassays, while aqueous extracts underestimate hydrocarbon toxicity. This study evaluated dimethyl sulfoxide (DMSO) as a biocompatible extractant for enzymatic bioluminescent toxicity assays employing the coupled NAD(P)H:FMN-oxidoreductase and bacterial luciferase (BLuc–Red) system. Soil samples artificially contaminated with diesel fuel were analyzed using DMSO extracts in combination with molecular dynamics (MD) simulations to examine enzyme stability in solvent environments. Moderate DMSO concentrations (4–6% v/v) maintained enzymatic activity, whereas higher levels caused partial inhibition. Diesel hydrocarbons dissolved in DMSO strongly suppressed luminescence, and soil extracts exhibited a clear dose–response relationship between contamination level and enzymatic inhibition. MD simulations confirmed that neither DMSO nor diesel induced large-scale unfolding of luciferase or reductase, though localized flexibility changes and partial dehydration of active site residues was observed, which may account for the detected inhibition of luminescence at higher DMSO concentrations. These results demonstrate that DMSO provides an effective and biocompatible extraction medium for enzymatic bioluminescent assays, enabling accurate toxicity evaluation of petroleum-contaminated soils and offering a promising tool for ecotoxicological risk assessment in oil-impacted environments.

The article aims to analyze the pricing processes in the wholesale electricity and capacity market of the Russian Federation and to identify their problems and peculiar features. The tested hypothesis of the study is that the peculiar features of pricing in united energy systems are explained by the influence of several separate but interrelated factors that cause multidirectional problems when generating and grid companies implement pricing strategies under the conditions of energy transition, which implies refocusing on renewable energy sources. The content-related methodology of the article includes the study of electric power and capacity pricing regularities and is based on the system approach. The research tools included analysis and synthesis, study and generalization, statistical and economic analysis, and graphical method. The adequate objectives of the article are represented by the scientific analysis of modern views of re-searchers on the problems and peculiar features of pricing based on the results of the evolution of publica-tions in this field; analysis of the current state of the energy industry in the Russian Federation; determining the volume of electricity consumption and actual generation in the Russian Federation; analysis of the dis-tribution of investment projects in the energy industry according to the structure of united Russian energy systems, and analysis of the problems and peculiar features of pricing in the territories of the Central IPS (integrated power system), the North-West IPS, the South IPS, the Middle Volga IPS, the Urals IPS, the Si-beria IPS, the East IPS. The results obtained according to the verification of the research hypothesis allowed identifying separate but interrelated factors which cause differently directed problems in the implementation of pricing strategies by generating and grid companies and affect the specifics of pricing: concentration of large industrial consumers; infrastructural development of energy facilities and the extensive power trans-mission network; competition between players in the wholesale electricity and capacity market; the share of regulated tariffs in the wholesale electricity and capacity market; development of investment raising in the electric power industry; compensation of costs incurred by generating and grid companies through state subsidies; introduction of technologies aimed at improving pricing management efficiency in electricity consumption demand management; nodal price management to ensure market equilibrium in pricing; price index management under various operating scenarios of the energy system. Brief results of the work reflect-ing the practical significance of the research findings are determined by their applicability in the activities of generating and grid companies of the RF energy industry aimed at improving pricing management effi-ciency under the conditions of energy transition and raising energy efficiency.