Soil contamination with chromium poses a serious threat to the environment and human health due to its toxicity and persistence. This study evaluates the effectiveness of iron-containing nanoparticles for the remediation of chromium-contaminated soils. Two types of iron nanoparticles synthesized and investigated: nanosized zero-valent iron (nZVI) and nano-magnetite (nFe3O4). Soil samples were mixed with nanoparticles at different doses, homogenized and incubated under controlled conditions for 10, 20, 30, 60 and 90 days. For each sampling time, chromium concentration and its leachability were analyzed. Chemical and phase composition analysis investigated by X-ray diffraction spectroscopy, atomic absorption spectroscopy and X-ray fluorescence analysis. Treatment with both types of iron nanoparticles showed a significant decrease in Cr concentration in aqueous extracts compared to the control samples. The leachability of Cr in the treated soil samples also decreased significantly and remained stable throughout the experiment. The results indicate that nZVI immobilized Cr by adsorption of Cr(VI) on the shell with its reduction to Cr(III). The interaction mechanism between nFe3O4 and Cr(VI) involved both adsorption [1], and reduction, although its reduction capacity was lower than that of nZVI. Analytical methods confirmed the change in soil chemical composition after treatment and separation of iron nanoparticles. This study demonstrates that iron-containing nanoparticles can effectively remediate chromium-contaminated soils under different environmental conditions.

Fe₃O₄ magnetic nanocomposite were synthesized from different techniques: Fe₃O₄ nanoparticles were synthesized by co- precipitation of salts in a carbon matrix (biochar, activated carbon) with the formation of Fe₃O₄/BC and Fe₃O₄/AC nanocomposites; and co-precipitation of FeCl₂/FeCl₃ with oleic acid, with formation of OL/Fe3О4 nanocomposite. Characterization techniques including XRD confirmed the spinel structure of composite matrix, with crystallite size around 20 nm. X-ray fluorescence analysis shows the presence of iron and oxygen elements, as well as impurity elements present in oleic acid and biomass carbon, respectively. The adsorption properties of all samples investigated for methylene blue (MB) dye removal. Adsorption tests were conducted at room temperature with magnetic separation of the spent adsorbent and photometric control at 665 nm. It found that magnetic composites effectively remove the dye, with AC/Fe₃O₄ achieving up to 96.6% removal at a concentration of MB 10⁻⁵ g/L.

The oil and gas industry is characterized by the presence and operation of various high-risk facilities, which contribute to occupational injuries and diseases, as well as environmental pollution. Among these, pipeline systems - particularly main gas pipe-lines - are prominent. The purpose of this research is to study the processes involved in the manual arc welding of main gas pipelines during construction and repair, which adversely affect human health and the environment. Gas pipeline welding during construction and repair is performed both in semi-enclosed spaces and in the open air. In both cases, manual arc welding is predominantly used due to its mobility and ease of implementation. The equipment required for arc welding is much cheaper and simpler than that used for laser, electron beam, or hybrid welding. These advantages have led to the widespread use of arc welding across various industries. However, manual arc welding has a considerable negative impact on human health and the environment due to the emissions of toxic substances in the form of welding aerosols. The regularities of aerosol formation during arc welding and the mechanisms of their distribution in the environment are examined, enabling the planning of welding operations in a way that reduces the risk of oc-cupational diseases. Empirical correlations were obtained to determine the concentrations of harmful substances. It was shown that an aerosol cloud, dispersed by wind, spreads with particles diffusing in all directions, leading to a rapid decrease in concentration. It was found that during the welding of pipes under moderate wind conditions, aerosol smoke from a point source spreads in the air in a conical torch shape, expanding both vertically and horizontally. It is substantiated that the main physical process involved is diffusion combined with heat transfer due to convective airflows. Based on Sutton's modified mathematical model, it was established that during the welding of above-ground pipelines under laminar wind conditions, aerosol smoke mixes with air solely through molecular diffusion, whereas during underground welding, aerosol dispersion is caused by the physical processes associated with the formation of a welding torch.

Metal corrosion is a serious technical and environmental problem that leads to significant economic losses and threatens the safety of infrastructure. Traditional methods of protecting metal structures are based on the use of chemical inhibitors, which are often toxic, poorly biodegradable and hazardous to human health and the environment. In response to these challenges, there is a growing interest in the development of “green” corrosion inhibitors - non-toxic, biodegradable and environmentally friendly substances derived from natural sources. This study examines the effectiveness of aqueous, alcoholic and water-alcohol plant extracts as an alternative to traditional corrosion inhibitors for the protection of 17GS steel in the NS4 model environment. Experimental studies have shown that the water-alcohol extract of Echinacea provides up to 69% protection of steel, the water extract of tea - up to 50%, while the effectiveness of eucalyptus oil was only 12%. The results obtained indicate a significant dependence of the protection efficiency on the type of plant material, extract concentration, exposure temperature, and duration of contact with the environment. Gravimetric analysis confirmed the formation of a dense protective adsorption-oligomeric film on the metal surface, which significantly reduces the corrosion rate and increases the polarization resistance of steel to 15 kΩ at a concentration of 40 ml/l. Microstructural analysis shows that the most effective compounds are those with aromatic structures and nitrogen-containing heterocycles that are able to form stable chemical bonds with the metal surface. A multivariate regression analysis of the dependence of steel corrosion resistance on exposure time, inhibitor concentration, and temperature was performed, which confirmed the significant impact of these factors on metal protection. The studies indicate that it is possible to optimize the composition of inhibitors by using combined herbal preparations and nanostructured additives to increase the duration and effectiveness of the protective effect. The results of this work open up new prospects for the development of environmentally friendly metal protection technologies that meet the concept of sustainable development and the principles of green chemistry. Further research should be focused on finding new sources of bioactive compounds, improving extraction methods, and in-depth study of the mechanisms of protective coatings formation.

This study investigates the impact of sewage sludge-based composts on the quality of sod-podzolic soils (Fluvisols, WRB), which are naturally acidic and low in fertility. A field experiment with eight variants was conducted, applying different doses of sewage sludge and composts mixed with organic materials to enhance soil properties. Energy crops, including Salix viminalis L., Miscanthus × giganteus, and Panicum virgatum L., along with Helianthus tuberosus, were cultivated in three replications to ensure research reliability. The study assessed changes in physicochemical soil properties, nutrient availability, and heavy metal accumulation within the soil-plant-ash continuum. Results indicated that compost application improved soil fertility, increased biomass yields, and influenced heavy metal dynamics, with variations depending on the applied compost type and dosage. The findings highlight the potential of sewage sludge composts to enhance soil productivity while maintaining environmental safety.

Studies carried out in the Transcarpathian region of Ukraine with the application of sewage sludge as fertilizer for Silphia prinosanolista showed that the use of 20-40 t/ha of fresh SS and composts based on it with cereal straw creates a different agrochemical background of alluvium, compared to the application of an equivalent norm of mineral fertilizers, and causes a change in the content of bioavailable forms of the main nutrients - nitrogen, phosphorus, and potassium in the soil layer 0-80 cm. Significant differences in the content of mineral and alkaline hydrolyzed nitrogen compounds in the upper layer of 0-40 cm of alluvium were established. Application of increasing (20-40 t/ha) rates of sewage sludge, as well as their composts with straw and a compensatory amount of mineral fertilizers, contributes to a reliable increase in the content of ammonium compared to the option without the application of fertilizers and the option with an equivalent dose of mineral fertilizers.

This scientific paper is dedicated to the study of the potential for using bioenergy crops, using the example of giant miscanthus on oil-polluted territories. Throughout the research, various fertilization schemes were applied to analyze their impact on the growth and development of miscanthus. The yield of energy and solid biofuel from the obtained biomass of giant miscanthus was determined. In addition, it was found that miscanthus has significant potential in the phytoremediation of contaminated lands and can contribute to the restoration of soil cover. The scientific work presents results from a three-year observation, demonstrating the widespread use of bioenergy crops, particularly miscanthus, for ensuring energy security and ecological balance.

The article analyzes the issue of disconnection of individual components of the pipeline systems of Ukraine due to a decrease in the transit of oil, oil products, and gas. It has been highlighted that the released capacity can be used to transport other products, in particular vegetable oil, which is economically feasible and can reduce costs and environmental impact. The methods of selecting pipeline sections for the transportation of other types of products are presented, in particular, the technical condition of pipelines and factors affecting their reliability are considered. The improvement of the method of calculating the hydraulic processes of pumping vegetable oils is presented.

The monitoring of natural and artificial gamma fields has become an indispensable auxiliary tool not only in the search for minerals or geophysical research but also as a standalone method for assessing environmental conditions during accidents, locating highly radioactive sources, and implementing anti- terrorist measures. Nowadays, the most actively developing method of monitoring gamma fields is the remote method, primarily involving the use of remotely piloted vehicles. Most problems of gamma field monitoring can be solved more effectively by incorporating appropriate mathematical support. In particular, accurately estimating the intensity of gamma radiation of contami- nated soils requires proper consideration of the processes affecting the formation of gamma quanta flow, including attenuation processes. Using the exponential law of gamma ray attenuation in a medium and their geometric divergence, we investigate the problem of gamma field intensity in a layered soil massif. In our research, we derived an analytical expression for describing the field intensity of a two-layer soil depending on the density, thicknesses, and mass attenuation coefficients of the layers, as well as the height of the detector above the soil surface. We identified unique characteristics in the behavior of the field intensity function for different layer configurations and at considerable heights above the soil surface. The algorithm for calculating the intensity of the gamma field is generalized for scenarios involving a finite number of layers. The results obtained could be valuable for developing solutions to inverse problems that arise during remote detection of gamma fields in contaminated areas using, for example, unmanned aerial vehicles.

Results of long-term exposure tests (20 months) of 17G1C and 13G1C-U pipeline steel samples in NS1-NS3 model environments (soil electrolyte imitations) are presented in the article. It was established that during the exposure of steel samples in the studied model environments the rate of corrosion processes depends on the component composition of the model environments, the grade of steel and pH. Regardless of the grade of steel, the highest corrosion rate was observed for the NS1 environment, while the corrosion rate for the NS3 environment was almost 21% lower. In the case of the NS2 model environment, the corrosion rate reduction for 17G1C steel was 38.68%, and for 13G1C-U steel – 28.75%, compared to the exposure of these samples in the NS1 environment. The calculated multiple coefficients of determination and linear correlation coefficients indicate a strong relationship between these indicators. The phase composition and structure of corrosion products were determined by the X-ray diffractometer Shimadzu XRD‑7000 using the method of X-ray structural analysis. On the basis of the obtained radiographs, the dominant form of iron oxide, which does not depend on the grade of steel, was determined for each environment. The research results have practical value and can be used in predicting the behavior of underground structures in soils of different corrosive activity.

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Abstract. Municipal sewage sludge is considered as an important resource for replenishing organic carbon and mineral nutrition elements in the soil. However, its widespread use in the agricultural sector is associated with the risks of soil contamination by pollutants, in particular heavy metals, and their inclusion in trophic food chains. A relatively ecologically safe way to dispose of sewage sludge is to apply it to energy crops. In order to study the influence of sewage sludge application on the ecological condition of podzolic soil and the level of heavy metal contamination of plant cover, research was carried out in the Transcarpathian region of Ukraine on a willow plantation of the second cycle of energy use and repeated application of fresh sewage sludge and its composts with coniferous sawdust and grain straw cultures in different doses. Research has established that under the influence of the application of sewage sludge, the indicators of the content of heavy metals in the roots and above-ground shoots of energy willow significantly changed. The highest doses of sewage sludge of 60–80 t/ha led to a significant increase in the content of As, Mo, and Pb compared to other research options. The content of Fe, Zn, Sr, Y in these options was at the level of the option where compost was applied (sewage sludge + straw (3:1) + cement dust 10%) – 40 t/ha. Also, the use of cement dust in this version led to the highest Nb content. Ni, Cu.The highest value of the Integral index of energy willow plant pollution ‒ 222 was recorded in the variant where fresh sewage sludge was applied at the rate of 80 t/ha, which was 17‒20 points higher than the values of the closest variants of the experiment

All rights reserved. Printed in the United States of America. No part of this publication may be reproduced, distributed, or transmitted, in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher. The content and reliability of the articles are the responsibility of the authors. When using and borrowing materials reference to the publication is required. The collection of scientific articles published is the scientific and practical publication, which contains scientific articles of students, graduate students, Candidates and Doctors of Sciences, research workers and practitioners from Europe and Ukraine. The articles contain the study, reflecting the processes and changes in the structure of modern science.

The cultivation of energy crops is an important component of renewable bioenergy, which pursues the goal of reducing greenhouse gas emissions and determines the effective management of fertility and land use of marginal lands and disturbed areas of various nature. As a result of the conducted research, convincing relationships were established between the application of sewage sludge with a compensatory dose of mineral fertilizers and the productivity of grassy energy crops. The greatest increase in green mass is provided by the application of SS (SS - 40 t/ha + N10P14K58) for all studied crops. Applying sewage sludge with the addition of mineral fertilizers is an effective way to increase the productivity of green mass by 57-64% for such energy crops as Jerusalem artichoke, Silphium perfoliatum L, Miscanthus giganteus, and switchgrass (Panicum virgatum L).