Visnyk of V. N. Karazin Kharkiv National University. Series Еcоlogy

Ecological assessment of surface water conditions of the Danube river

L. A. Horoshkovа — 2025-06-30

Purpose. To provide a comprehensive environmental assessment and forecasting of the condition of surface waters of the Danube River within the Ukrainian section (Reni – Izmail – Vylkove), with a focus on the dynamics of key hydrochemical indicators over the period 2010–2024. Special attention is given to the influence of anthropogenic factors, including intensive navigation, industrial pressure, and the environmental consequences of military actions, which have altered the hydrological regime and deteriorated water quality.

Methods. System analysis, statistical data processing, distribution analysis, and regression modeling were employed to assess retrospective dynamics and predict future trends in water quality. The information was sourced from long-term monitoring data collected at observation stations in the cities of Kiliya, Vylkove, and the river’s mouth.

Results. The analysis focused on six key water quality indicators: phosphates, ammonium, sulfates, chlorides, biochemical oxygen demand over five days (BOD₅), and dissolved oxygen concentration. Phosphate and ammonium compounds exhibited seasonal fluctuations, attributed to discharges of organic and agricultural origin. Sulfate concentrations were found to be highly variable, combining both natural and anthropogenic sources, while chloride levels remained stable with signs of chronic influence. The analysis of BOD₅ and dissolved oxygen indicators suggests a potential for self-purification, although certain periods revealed deterioration in oxygen balance, particularly due to localized organic overload and disrupted hydrodynamics. Developed regression models allowed the identification of relationships between hydrological changes, port activity intensity, and pollution levels.

Conclusions. The main environmental issues of the lower Danube were identified as organic and mineral pollution, eutrophication, decreased oxygen levels, hydromorphological changes, and threats posed by armed conflict. Despite these challenges, the river retains a capacity for partial self-recovery, especially under reduced anthropogenic pressure. Restoring ecological balance will require the implementation of systematic monitoring, modernization of wastewater treatment facilities, effective pollution source management, and Ukraine’s active participation in international environmental regulatory mechanisms, such as the Danube Commission. The modeling results can be used to forecast water environment conditions in both peacetime development and post-war recovery scenarios.

Costs and water ecological state of the greatest inflow of Rosi river – river Rostavitsya

P. S. Lozovitsky — 2025-06-30

Purpose. To establish the flow and ecological state of the water of the Rostavytsia River, to assess the suitability of water for water supply and irrigation according to irrigation indicators.

Methods. System analysis, methods of mathematical statistics.

Results. An analysis of the long-term (1940-2019 with interruptions) results of the study of the morphological parameters of the riverbed, daily, monthly, average, maximum and minimum water flows per year, the dynamics of the chemical composition, mineralization of the water of the Rostavytsa River and the state of pollution by biogenic and specific substances of toxic action, heavy metals, petroleum products, phenols, SPAR in comparison for different periods of time: 1940-1947, 1972-1980, 2003-2010, 2011-2020, 2021-2022 is presented. It was determined that due to significant regulation of the flow, the spring flood is characterized by a slow increase in levels, the largest monthly water flows are characteristic of April, By the chemical composition of the water of the river Rostavitsa in 2000-2022 is characterized by average mineralization values, hydrocarbonate, calcium, medium hard, weakly alkaline. The highest salt concentrations were observed in 2007, 2016 and 2018. Water pollution of the Rostavitsa River with nitrite nitrogen is assessed as stable, moderately-highly polluted, with nitrite nitrogen - stable, moderately-highly polluted, with nitrates - the water is dirty. According to the water pollution index - the water is moderately polluted.

Conclusions. The largest monthly water flows of the Rostavitsa River are characteristic of April, by chemical composition and mineralization the water is suitable for water supply, but the presence of toxic elements and substances such as iron, manganese, nickel, lead, cadmium, phenols, petroleum products in its composition requires water treatment and purification.

Innovations in the organization of ecological (green) tourism: regional peculiarities

N. V. Maksymenko — 2025-06-30

Purpose. To search for new, systematic approaches to the development of ecological tourism in Ukraine, based on strategies of sustainability, innovation and integration with the local socio-economic context.

Methods. The comparison was made on the basis of a retrospective analysis of literature, stock and Internet resources on the organization of ecological tourism. Distances were measured using the Google Maps mapping service.

Results. The study has revealed characteristic regional differences in approaches to the organization of ecological tourism in three regions of Ukraine, namely: in Zakarpattia it is a combination of health improvement and cultural heritage, in Lviv region - outdoor activities with ethnic elements, in Kharkiv region - eco-practices with elements of rural life. A new information form for green tourism is proposed - a matrix of tourist accessibility, which is a form of visualization of the distances between key settlements and tourist locations in the region. Firstly, it visualizes transport accessibility: a tourist can easily find out how quickly it is possible to get from a particular estate to the chosen object. Secondly, it helps to plan routes efficiently - you can build both shortest routes and thematic routes based on objects of the same type (for example, castles, waterfalls, farms, etc.). Thirdly, the matrix supports an informed choice of a farmstead: a tourist chooses the one that is closest to the desired locations.Initial versions of the matrix and sets of radial diagrams have been developed for three model regions of Ukraine (Transkarpattia, Lviv, and Kharkiv).

Conclusions. The matrix, as a proposed innovative tool for green (ecological) tourism, has a wide range of functionalities. The implementation of the proposed initiatives will ensure the effective use of natural and cultural resources, create new jobs and increase the competitiveness of Ukrainian regions in the tourism market, both domestic and international.

Forecast of organic matter content in the waters of the Danube river (Kilia)

V. V. Terzeman — 2025-06-14

Purpose. To assess and forecast the risk of water quality deterioration in the Danube River within the city of Kiliya based on the biochemical oxygen demand (BOD₅) indicator.

Methods. Statistical analysis methods were applied, including the lognormal distribution to estimate the probabilities of exceeding threshold concentrations, and extrapolation of the trend line to forecast the dynamics of the BOD₅ indicator. Data visualization was performed by constructing graphs for various time intervals.

Results. The comparison between actual and forecasted BOD₅ values showed a satisfactory level of discrepancy (up to 17% for risk assessment and up to 5% for actual values), confirming the effectiveness of the chosen approach even under conditions of irregular monitoring data, while taking into account ecological standards and EU Directive requirements. It was found that the concentration of organic substances in the water at the 10% probability level significantly exceeds the ecologically permissible value of 3 mg/dm³ (according to EU standards) and shows a tendency for gradual increase.

Conclusion. The results of the study confirm the effectiveness of the applied approach to water quality forecasting under conditions of irregular monitoring. The use of the lognormal distribution combined with trend line extrapolation allowed for reliable estimations of both the actual state of the water and the probability of exceeding ecologically hazardous concentrations.

Influence of railway transport enterprises on the state of surface waters using the example of Kharkiv region

H. O. Zlenko — 2025-06-30

Purpose. To determine the impact of one of the railway transport enterprises on the state of surface waters on the example of the Lozova River in the Lozova District of the Kharkiv Region based on the determination of water quality indices.

Methods. The water pollution index (WPI), the modified water pollution index (WPI mod) and the combinatorial water pollution index (CPI).

Results. It was determined that changes in water quality occur after the discharge of wastewater from one of the railway transport enterprises, a deterioration in water quality is observed by 1.004 times according to the average WPI value and 1.070 times according to the average modified WPI value. According to the average PCPI, on the contrary, there is an improvement in water after discharge by 1.016 times. This was influenced by the exceeding of the MPC for suspended solids at the point of wastewater discharge in 2022. The water quality of the Lozova River according to the method of assessing the WPI and modified WPI belongs to the II class of water quality and is characterized as “clean”. According to the CPI method, the river water in 2020, 2021 and 2022 also belongs to the II class of water quality, but has the characteristic of “polluted”, and in 2023 and 2024 the water belongs to the I class of water quality and has the characteristic of “slightly polluted”. The hydrochemical indicators that determined the water quality class of the Lozova River are SPAR, chlorides, phosphates and suspended solids.

Conclusions. The one of the enterprises of JSC "Ukrzaliznytsia" does not significantly affect the quality of surface waters of the Lozova River in the Lozova district of the Kharkiv region.

Biopreparations application in Aesculus hippocastanum plantings

V. V. Gololobov — 2025-06-30

Purpose. To determine the effectiveness of integrated biological protection of urban chestnut (Aésculus Hippocástanum L.) plantations affected by chestnut borer and rust.

Methods. Field, laboratory, method of photofixation of the results of the field experiment.

Results. The positive effect of treatment with biological products on the phytosanitary condition of chestnut leaves was established, which was confirmed by photographic fixation and analysis of the content of photosynthetic pigments. In unaffected treated leaves, the nitrogen content is almost twice as high as in the leaves of untreated chestnuts, which is an important factor for plant growth and development. Increased absorption of macronutrients (phosphorus, potassium) and trace elements (iron, cobalt, copper, zinc) in untreated trees is a mechanism of adaptation to stress caused by pests and diseases.

Conclusions. Thanks to the combination of biological products with fungicidal, insecticidal and acaricidal action, it is possible to effectively reduce and control the phytosanitary condition of urban plantings.

Environmental principles of using biocharol for wastewater treatment

Z. V. Lavrynyuk — 2025-06-30

Purpose. To study the effectiveness of using biochar as a sorbent for wastewater treatment from organic and inorganic pollutants on the adsorption process, as well as to assess the environmental feasibility and possibility of reusing biochar in water treatment technologies.

Methods. Experimental, adsorption atomic spectroscopy on the UNICAM Solaar 939 device, statistical.

Results. The influence of the initial concentration, pH of the medium, sorbent dose and contact time was studied. It was found that strong adsorption of pollutants on biochar in aqueous solutions reduces the mobilization of pollutants and helps reduce the risk associated with toxic chemicals and their by-products that are present in wastewater and can negatively affect the environment. The pH value of the medium significantly affects the surface charge and specification of chemicals in all biochar sorbents. High concentrations of pollutants complicate complete removal. The use of biochar removes contaminants best in conditions of low initial concentrations of contaminants. The efficiency of purification increases with the contact time, which is associated with the duration of the process between biochar and the contaminant. However, an excessive increase in time can lead to saturation, which will limit the efficiency of contaminant removal. The ecological safety of the use of biochar and its suitability for repeated use with minimal loss of sorption properties have also been confirmed.

Conclusions. It has been established that biochar is an effective sorbent for the removal of contaminants from aqueous solutions due to its physicochemical properties: large specific surface area, developed porosity and the presence of active functional groups. Biochar is a promising material for implementation in wastewater treatment systems in industry, agriculture and everyday life.Key words: water pollution, adsorption, biochar, wastewater, concentration, pH.

Undermining of Kakhovka HPP: environmental consequences and remediation of damaged territories

Y. V. Voitenko — 2025-06-27

Purpose. Study of the environmental consequences of the destruction of the Kakhovka hydroelectric station, analysis of the impact of water pollution for the population, flora and fauna, assessment of the impact on agriculture and study of possible ways to restore the territory.

Methods. System analysis, statistical methods.

Results. Water pollution by garbage, oil products, chemical and hazardous, organic and biogenic substances, as well as bacteria and viruses has been identified. It is determined that negative phenomena as outflow of water and flooding caused large-scale damage not only to the population, which were forced to evacuate due to the threat to life, but also to the economy of the country, which suffered as a result of the defeat of agricultural land. In particular, a decrease in the area of irrigated land and, as a consequence, a decrease in the total production of agricultural crops, such as vegetables, grains and legumes, oilseeds, etc. The tragedy also caused the death of a large number of representatives of the plant and animal world due to significant flooding of the territory. Considered promising ways to overcome the environmental consequences of this disaster. Urgent tasks are the use of methods of restoring land depending on environmental conditions and available resources.

Conclusions. Significant negative impact on both environmental elements, including water bodies and soils, and on the country's economic development due to damage to agricultural lands has been identified. The importance of the task of applying means to restore damaged areas, including methods of biological remediation, geoengineering and carbonate mineralization technologies, has been proven.

Accumulation of heavy metals (Cu, Cr, Pb, Cd) in aquatic invertebrates from the hyperhaline Kuyalnyk estuary (Ukraine, North-Western Black Sea region)

G. M. Shykhaleyeva — 2025-06-30

Purpose. To investigate the content of heavy metals (Cu, Cr, Pb, Cd) and the features of their migration and accumulation in the components (Artemia salina: biomass of individuals of and eggs (cysts), Chironomus salinarius larvae, water, bottom sediments) of the Kuyalnyk Estuary ecosystem.Methods. Atomic absorption spectrophotometry, hydrochemical, biological, automated analysis methods and static analyses.

Results. This is the first study of the accumulation of Cr, Cu, Pb, Cd in the biomass of gill crustaceans A. salina and larvae of Ch. salinarius, extracted from the hyperhaline Kuyalnyk estuary. It was determined that the average heavy metal content in the components of the aquatic environment is represented by the following regression series: Water: Pb > Cu > Cr > Cd ; Bottom sediments: Cu > Pb > Cr > Cd; Crustaceans and cysts of A. salina: Pb > Cu > Cr > Cd; Larvae of Ch. salinarius: Cr > Cu > Pb > Cd. Intensive accumulation of heavy metals in bottom sediments, crustaceans A. salina and larvae of Ch. salinarius compared to water is shown, which is confirmed by the coefficients of bottom accumulation and bioaccumulation. A. salina and larvae of chironomids Ch. salinarius are effective concentrators of the studied heavy metals, especially lead and chromium. It was found that A. salina accumulates Pb and Cd more intensively, while Ch. salinarius accumulates Cr the most.

Conclusions. Hydrobionts of the Kuyalnyk estuary (A. salina and Ch. salinarius) are informative bioindicators of chemical pollution of water bodies with heavy metals, with the effective transfer of these metals to the biota mainly from water. The concentrations of Cd and Pb in these organisms do not exceed the permissible levels for animal feed, which indicates their potential safety for use. The obtained data are important for the scientific and biological justification of the use of bioresources of the Kuyalnytskyi estuary and saline water bodies in general.

Flowers spectral characteristics of the invasive heliophyte species Erigeron canadensis l.

V. S. Fedenko — 2025-06-30

Purpose. Determination of spectral characteristics of Erigeron canadensis L. flowers to confirm the photoprotective effect of flavonoids and identify the raw material.

Methods. The reflectance spectra were obtained in the range of 350–800 nm. The colorimetric parameters were determined in the CIE XYZ and CIE L*a*b* systems. For additional identification of flavonoids, the flowers were extracted with isopropanol and chemisorption of compounds from the extract on the surface of biocompatible aluminum oxide was carried out, followed by determination of spectral characteristics.

Results. The selection of flowers was carried out at the flowering stage in an open meadow area near the Mokra Sura River (Novooleksandrivka, Dnipropetrovsk region), taking into account that the best development of heliophytes is observed under conditions of full illumination. For the first time, the reflectance and colorimetric characteristics of flowers were determined to determine the light-absorbing ability of horseweed as an invasive heliophyte species at the flowering stage. A defining feature of the reflectance spectra of flowers is the increase in the intensity of the maximum of UV-absorbing flavonoids compared to carotenoids and chlorophylls, which are localized in surface tissues. Differentiation of the spectral reflection curve of flowers turned out to be an effective way to increase the degree of distribution of the detected maxima. The studied flowers were also characterized by a specific set of colorimetric parameters. Flavonoids as a biologically active component were identified due to their chelating properties by chemisorption from a plant extract on biocompatible aluminum oxide and subsequent determination of the reflectance and colorimetric characteristics of the interaction product.

Conclusions. Increased localization of ultraviolet-absorbing flavonoids in the surface tissues of flowers determines the increase in photoprotective ability as an adaptive enhancement of the reproductive system of the invasive heliophyte species. The results can be used to confirm the functional signs of invasiveness of alien plants, as well as to identify the raw material of horseweed and when using the resource potential of this species to obtain biologically active drugs.

Relevance of teaching the course “Ecological threats in the national security of Ukraine” in higher school

O. R. Perkhach — 2025-06-23

Purpose. To update the discipline “Ecological Threats in the National Security of Ukraine” as a necessary educational component today, since it is aimed at providing the necessary theoretical knowledge and skill that are mandatory for the formation of masters in the specialty 106 “Geography” of systemic knowledge about the most important environmental threats in Ukraine.

Methods., Systems analysis, and the principle of interconnection.

Results. The works of Ukrainian scientists are analyzed, and the Standards of Higher Education of Ukraine, methodological recommendations for the development of higher education standards, resolutions of the Cabinet of Ministers of Ukraine and other regulatory documents are considered. The structure of the academic discipline and the main topics of lectures, seminars and practical classes are presented. General and professional competencies are given, with the help of which the study of the discipline is ensured. The main environmental threats to the national security of Ukraine and ways to overcome them are characterized. Aspects that need to be taken into account to achieve success in the process of overcoming the consequences of the Russian-Ukrainian war are highlighted, namely: ecosystem restoration; cleaning of contaminated resources; global cooperation; socio-economic rehabilitation, ecological security and national security. The program learning outcomes are revealed: to apply the acquired theoretical knowledge and practical skills to study natural and socio-territorial systems at different levels of spatial organization; participate in the development of programs and strategies for urban and regional development, planning of territories of various hierarchical levels; assess possible risks, identify types of threats and their regional features of functioning, socio-economic and geo-ecological consequences of implementing management decisions in the field of nature management, urban and regional development, recreation and tourism; plan and carry out theoretical and applied research, draw substantiated conclusions, analyze and present research results.

Conclusions. The academic discipline “Environmental Threats in the National Security of Ukraine” is expedient to teach to students of specialty 106 “Geography” of the second (master's) level of higher education. Theoretical and practical training of future specialists will create safe conditions for life and activity in the living environment, its study and practical application in the future will be the result of the future of our state.

Conferences of the Karazin Institute of Environmental Sciences with the support of the Erasmus+ projects SUNRISE and DOMANI

А. A. Hrechko — 2025-06-30

Traditionally, three conferences were held at the Karazin Institute of Environmental Sciences in spring, namely: All-Ukrainian Student and Postgraduate English-language Conference “Ecology is a Priority”, IV International Internet Conference “Actual Problems of Formal and Non-Formal Education in Environmental Monitoring and Conservation” and ХХVII International conference «Ecology, environmental protection and balanced environmental management: Education – Science –Production – 2024». The conferences are devoted to the following topics: modern environmental problems and ways to solve them, applied environmental research, environmental consequences of the Russian-Ukrainian war and ways of post-war revitalization of natural complexes. In addition, much attention is paid to the problems and prospects of nature conservation in Ukraine and the world, environmental monitoring, and formal and informal education in environmental monitoring and conservation. The highlight of this year's conferences was their holding under the auspices of two international projects: Erasmus + SUNRISE - Supporting the Next Generation of Ukrainian Scientists: Project to Enhance University Capacity and Improve Doctoral Training and DOMANI - Development of Microcredit Ecosystems in Ukraine and Mongolia for a Competitive and Sustainable Green Economy. The materials of all conferences were published in collections of abstracts, posted in the Karazin University repository, and participants received Certificates of Participation.