A study of the levels of persistent organochlorine pesticides (OCPs) in marine mammals of the Black Sea in 2018–2022 revealed a statistically significant relationship of the accumulation levels with the sex of the animals (males were more contaminated than females) and with the age group (adults and adolescents were more contaminated than calves and newborns). The location of tissue sampling for analysis was also an important factor: OCPs accumulated more in dorsal than in caudal blubber. In blubber of Black Sea harbor porpoises and common dolphins, the mean concentrations of OCPs decreased in the order p, p'-DDE > β-HCH > p, p'-DDD > p, p'-DDT; in the common bottlenose dolphin, they decreased in the order p, p'-DDE > p, p'-DDD > β-HCH > p, p'-DDT. The most widespread and highly concentrated metabolite was found to be p, p'-DDE. The concentration of p, p'-DDD was markedly lower; significant tissue concentrations of p, p'-DDT were observed much less frequently than all other metabolites and were among the lowest of all metabolites. Based on an analysis of variations in the mean concentrations of the sum of DDT metabolites in Black Sea harbor porpoise tissues, as reported in literature sources, we can claim that there is currently a significant decrease in the concentrations of these toxicants.

Introduction. Aquaculture is one of the sectors of food production in which antibiotics are widely used. Taking into account the global problem of increasing drug resistance of microorganisms, aquaculture targets can serve as reservoirs for the accumulation, selection and distribution of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB). Relevance. Currently, the ubiquity of antibiotic resistance genes is one of the threats to public health. Aim. This review discusses the results of studies of antibiotic resistance genes isolated both from various aquaculture environments (water, sediments, sewage) and from resistant bacteria that have etiological significance in the occurrence of diseases of commercial fish species, molluscs, crustaceans, etc. Methods. The analysis of both foreign and domestic publications has been carried out. In foreign studies, molecular genetic methods of detecting ARGs in total DNA samples of aquaculture targets are mainly used. The metagenomic quantification of the bacterial communities and ARGs by sequencing is the most indicative one. Results. Despite the relevance of the topic, there are no available publications that are directly devoted to the resistomes in the targets of the Russian aquaculture. Basically, the study of antibiotic resistance in this area focuses only on the phenotypic manifestations of the resistance of fish pathogenic bacteria to the antibiotics widely used in the Russian aquaculture. Conclusion. Accumulated research results on this subject matter are quite extensive; their summarization within a single review article might facilitate the further work in this area.

Accumulation of persistent organochlorine pesticides (OCP) in fat tissue was examined for the mammals found released ashore along the Crimean coast of the Black Sea in 2018–2022. This group of animals is positioned at the top of food chain in the local marine ecosystem. Statistically significant dependence of the accumulation on sex (males are more contaminated than females) and age (adults and juveniles are more contaminated than calves and neonates) is found. Besides, the pesticides concentration in fat from dorsal tissue is generally higher than in fat from caudal stem, but the difference is not significant. In the tissue of harbor porpoises and common dolphins, the mean OCP concentration decreased in the order: p,p′-DDE > β-HCH > p,p′-DDD > p,p′-DDT, whereas bottlenose dolphins had the order: p,p′-DDE > p,p′-DDD > β-HCH > p,p′-DDT. The most common metabolites were DDE, and their accumulation was the highest. The concentration of DDD was considerably lower, and significant accumulation of DDT was observed rarely, so the mean concentration of these group of metabolites was the lowest.

В р. Темерник в пределах г. Ростова-на-Дону в воде и донных отложениях отмечен высокий уровень загрязнения нефтепродуктами и полициклическими ароматическими углеводородами. Наиболее загрязнены участки реки в районе рынка «Темерник», Змиевской балки, Ботанического сада Южного федерального университета, автовокзала и устья. Превышение ПДК нефтепродуктов обнаружено более чем в 80 % проанализированных проб воды. Кратность превышения ПДК в воде варьировала от 0,4 до 82,8 раза. В подавляющем большинстве проанализированных проб воды р. Темерник результаты люминесцентного метода в 1,3 13 раз превышали результаты инфракрасного метода, что свидетельствует о накоплении стойких к процессам деградации люминесцирующих полициклических ароматических углеводородов. Полученные данные свидетельствуют о хроническом характере нефтяного загрязнения воды р. Темерник на участке от рынка «Темерник» до устья. В донных отложениях реки концентрации нефтепродуктов варьировали от сотых долей (0,04 г/кг) до аномально высоких значений (200 г/кг сухой массы). Согласно усредненным данным, полученным в различные сезоны 2018 2020 гг., по увеличению нефтяного загрязнения донных отложений участки р. Темерник располагаются в следующем порядке: Ростовское море, Верхнее водохранилище, Верхнее водохранилище 2, Камышеваха, Нижнее водохранилище, Сурб Хач, автовокзал, рынок «Темерник», Змиевская балка, Ботанический сад, устье. Концентрации суммы полициклических ароматических углеводородов в воде различных участков р. Темерник менялись в пределах 91,6 505,6 нг/л, в донных отложениях – 277,6 2939 мкг/кг сухой массы. Максимальные их концентрации в воде и в донных отложениях обнаружены в районе автовокзала. Превышения предельно допустимой концентрации нафталина (4000 нг/л) и бенз(а)пирена (10 нг/л) в исследованных пробах воды не обнаружено. В составе полициклических ароматических углеводородов в воде доминировал нафталин, в донных отложениях – флуорантен.

At present, the Azov Sea ecosystem exists in the context of continuously decreasing continental runoff and increasing water salinity, which reached in 2020-2021 the highest values for the entire period of observations since 1962. The increase in water salinity inevitably leads to the transformation in the composition of biological communities, which has a pronounced effect on the environment and fisheries. This paper discusses the long-term impact of water salinity on the development of near-bottom hypoxic phenomena and on the volume of primary production of organic matter by phytoplankton in the Taganrog Bay during the summer season (1962-2021). A statistical ecosystem analysis describing the contribution of the major hydrological and hydrochemical factors into the processes of hypoxia formation in the bottom water layer of the Taganrog Bay has been performed. It is shown that the desalinization of the waters of the Taganrog Bay in 1993-2008 was accompanied by the increase in the size of hypoxic zones in the bottom water layer. During the modern period of salinization extending from 2009 to the present, there has been recorded a decrease in the scale of oxygen deficiency in the Taganrog Bay. The most crucial contribution to the hypoxic processes in the Taganrog Bay is provided by the stability of water masses, water temperature, organic nitrogen concentration, and the water salinity (due to the effect of salinity on the stability of water masses). During the streaks of the Taganrog Bay salinization, the decrease in the stability of water masses and in the content of organic nitrogen and phosphorus in the water (crucial factors in the formation of hypoxic zones) has been recorded. The highest rates of the primary production of organic matter by phytoplankton in the Taganrog Bay were observed during the desalinization period of 1962-1968, and the lowest ones were recorded during the salinization periods. The results of this assessment have exposed the significant relationship: the primary production of organic matter depends on the average annual runoff of the Don River, the water salinity, and the concentration of mineral nitrogen.

The aim of the article is to study the bottom sediments of the coastal zone of Kazantip peninsula in the Sea of Azov of complexes of hydrocarbon pollution. This water area is a site with a high level of recreational load, despite the presence of a nature reserve there, and is also characterized by a rugged coastline, which causes the accumulation of pollution in bottom sediments. The material for the study was samples of the upper layer of bottom sediments, which were taken in the summer of 2021 in the coastal waters of Cape Kazantip (Sea of Azov) with a manual sampler from depths of up to 1.5 m both within the protected area and beyond its borders. Determination of hydrocarbons in bottom sediments was carried out by gas and liquid chromatography in accordance with certified methods. The paper presents new original materials on the distribution of hydrocarbons in bottom sediments in the area of Kazantip peninsula, as well as an assessment of the local level of pollution of marine soils in this area. The ratio of hydrocarbons of different origin in bottom sediments is given. In addition, possible ways and sources of pollution are indicated. As a result of the study, it was shown that the bottom sediments of the coastal zone of Kazantip peninsula are not polluted and the concentrations of the main groups of hydrocarbons are within the range of average values for the Sea of Azov. But, despite this, there are traces of fresh inflows of petroleum hydrocarbons, which can be of both anthropogenic and natural origin.

The level of contamination of sea bottom sediments with polycyclic aromatic hydrocarbons in Balaklava Bay (the Black Sea) was studied. The dependence of polycyclic aromatic hydrocarbons content from sea bottom sediments grain-size distribution and anthropogenic load was estimated. The total average content of these pollutants in the Balaklava Bay water area was 2460 ng/g. The date obtained evidence that sea bottom sediments varied from natural pure to moderately pollute. The polycyclic aromatic hydrocarbons increased concentrations were noted in the eastern coast and the central part of the bay. 14 polyaromatic hydrocarbons were identified, 4 of which (naphthalene, 2-methylnaphthalene, fluorene, anthracene) had a trace content. The calculated molecular indexes indicated polycyclic aromatic hydrocarbons miscellaneous origin (pyrogenic and petrogenic nature of contaminants). An elevated content of benzo(a)pyrene was fixed practically over the entire water area of the bay. Taking into account the grain-size composition of the bottom sediments the central part of the bay (the eastern coast) was highly polluted according to this indicator. The inner and seaward parts of the bay were relatively clean. The amount of polyarenes correlated with the share of silt fraction (0.05–0.1 mm). Due to the increase of molecules mass, the dependence of the concentration of individual mass fractions of polyaromatic hydrocarbons in fine-dispersed sediments significantly increased (r = 0.99). In coarse-grained sediments it decreased (r = 0.89). No correlation was found between the presence of aleuritic fractions (up to 0.05 mm) and the polyaromatic compounds content.

ОЦЕНКА ЗАГРЯЗНЕНИЯ ДОННЫХ ОТЛОЖЕНИЙ АЗОВСКОГО МОРЯ МЕТОДОМ БИОТЕСТИРОВАНИЯ C ИСПОЛЬЗОВАНИЕМ БИОЛЮМИНЕСЦЕНТНЫХ ТЕСТОВ

The main sources of pollutants entering the Don R. ecosystem in its lower reaches are discussed. The principal sources are navigation, construction of new berths, dredging operations, and transshipment. At the economic revival, the level of anthropogenic load increases every year, producing an adverse effect on the ecosystem. Data of observations carried out in the recent 5 years and focused on the pollution level of water and bottom sediments by oil products, stable organochlorine pesticides, congeners of polychlorinated biphenyls, heavy metals (mercury, lead, cadmium, copper, iron, zinc, chromium, nickel, and manganese), and arsenic. The stable dynamics of accumulation of some pollutants in bottom sediments is demonstrated. Some hazardous toxicants were found to accumulate in the tissues of commercial fish in the Don. The pollution of water and bottom sediments was evaluated in accordance with the Russian and regional standards and the accumulation of toxicants in commercial fishes was evaluated in accordance with the Technical Regulation of the Customs Union.

ОЦЕНКА ТОКСИЧНОСТИ ТКАНЕЙ ПИЛЕНГАСА ПРИ ПОМОЩИ ЦЕЛЬНОКЛЕТОЧНЫХ БАКТЕРИАЛЬНЫХЛЮМИНЕСЦЕНТНЫХ СЕНСОРОВ

Ихтиофауна морских и континентальных водоемов

. The results of investigation of the pollution of the water and bottom sediments of the Caucasian Shelf in the Black Sea by heavy metals (copper, zinc, lead, cadmium, mercury) and arsenic, as well as their content in the Black Sea turbot Scophthalmus maeoticus (Pallas, 1814) are presented for 1995–2020. In the water and turbot, the determination of Zn, Cu, Pb, As, and Cd has been conducted using the method of atomic absorption with electrothermal atomization; mercury in all components of the ecosystems was measured using the method of atomic absorption with “cold steam”; in the bottom sediments, the content of Zn, Cu, Pb and As was identified using X-ray fluorescence method. In 1995–2020, in some water samples, the concentrations of zinc, copper and mercury exceeded the maximum permissible level established for the water bodies of fisheries importance, while the lead and cadmium were below it. The arsenic content during the entire observation period was extremely low. A noticeable decrease in the concentrations of zinc, lead and copper in the shelf waters of the Black Sea in the present period as compared with the years of the greatest pollution (1995–2002) was recorded. In the bottom sediments, the content of lead, zinc and mercury exceeded their content in the earth's crust for several years; for arsenic, the excess was recorded throughout the entire observation period. This mostly results from the peculiarities of the granulometric composition of the shelf bottom and, to a much lesser extent, from anthropogenic influence. The differences in the bioaccumulation of heavy metals and arsenic in the organs of the Black Sea turbot are shown. Out of the identified elements, only lead, mercury and arsenic in isolated cases exceeded the permissible level in the organs of the turbot in some years.

. The Azov limans of the Krasnodar Territory are of major fishery importance, as they serve as the spawning grounds for valuable semi-anadromous fish species. Roach and zander at their early stages of development are highly susceptible to the negative effects of various abiotic environmental factors, which makes them very dependent on the hydrochemical status of the water bodies during the spawning season. As the hydrochemical regime, in turn, closely depends on the hydrological regime and the overgrowth area of the limans, it can be used as a criterion parameter that affects the success of spawning of the semi-anadromous fish species and growth of their juveniles. This paper proposes a system of hydrochemical scoring and establishes the criteria for the typification of the limans based on their suitability for spawning and growing of zander and roach following the data collected in the spring season of 2017–2021. Based on the analysis of the hydrochemical data, 3 main blocks for the typification of limans according to their suitability for spawning of semi-anadromous fish species were identified: gas conditions, ionic composition and the content of biogenic components in water along with an assessment of the primary production of phytoplankton. It has been found out that the Azov limans of the Krasnodar Territory vary significantly in terms of the hydrochemical composition of their water. Some limans are characterized by pronounced fluctuations of the hydrochemical and ichthyological characteristics in interannual dynamics. Based on the hydrochemical criteria, the limans of the Kulikov-Ordynsk group (Bolshoy Bashtovy, Donchikov, Bolshoy Grushchany) and the Kulikovskiy Liman were the most favorable for the spawning of zander and roach, and the Ryasnoy, Boykievskiy and Kurchanskiy Limans were the least favorable. The low production coefficient in the water of most limans can be indicative of their high degree of overgrowth with macrophytes, which control is crucial in increasing the efficiency of natural reproduction of semi-anadromous fish species. The correlation between the criterion scoring of the limans based on the hydrochemical regime and the density of distribution of zander and roach juveniles has been established, which confirms the validity of this study.

The results of studies of oil pollution (by the sum of hydrocarbons and resinous substances) of water and bottom sediments in the northeast Black Sea in spring and autumn are presented. It is revealed that the mean oil pollution of the sea water has decreased in comparison with the data of 2001–2010, but remains quite high in some areas. The most polluted regions include the Kerch prestrait zone and the sea area between the cities of Anapa and Gelendzhik, where n-alkanes are dominated by oil homologues. The pollution of bottom sediments in the coastal sea area is higher in the period of 2016–2020 as compared to 2001–2010. Terrigenous hydrocarbons are present in bottom sediments along with petroleum hydrocarbons. Pollution of bottom sediments is increased in the areas of Abrau-Dyurso, Yuzhnaya Ozereevka, and Arkhipo-Osipovka. Taking into account the particle-size composition (according to the multiplicity of the mean typical concentration), bottom sediments of the Kerch prestrait zone are also assigned to the areas of increased pollution.

The content and composition of polycyclic aromatic hydrocarbons have been studied in the water column (surface layer, thermocline layer, at a depth of 500 m and the bottom layer) of the deep-water areas of the Black Sea near the Crimean Peninsula and the Caucasian coast, and the results are presented. The identified PAHs included naphthalene, 2-methylnaphthalene, phenanthrene, anthracene, fluoranthene, pyrene, triphenylene, chrysene, benz (b) fluoranthene, benz(k)fluoranthene, benz(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene. The concentrations of the total PAHs detected near the capes Sarych and Chauda were the highest, 532 and 593 ng/L, respectively. The distribution of PAHs over the horizons did not have a clear pattern. The composition of PAHs was dominated by 2-nuclear compounds, namely, naphthalene and 2-methylnaphthalene, their share on average accounted for 63 % of the total of the PAHs identified. The most dangerous nuclear PAHs containing 5 and 6 aromatic rings (benzo(b)fluoranthene, benz(k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene) accounted for less than 0.5 % in all the analyzed water samples. According to the calculated indices of technogenicity and pyrogenicity, PAHs of naphthydogenic origin predominated in almost all analyzed water samples. PAHs of technogenic oil origin prevailed in the water samples taken in the zone of shipping lanes to the port of Novorossiysk.

The results of content estimation of 8-e most common toxic heavy metals in the water column of the North-Eastern Black Sea in 2000-2019 are presented. Annual ranges for the content of individual heavy metals in the water column are given. Identified values have been compared with the pollution levels for the water bodies of fisheries importance as they are defined in the relevant normative and regulatory framework. Cases of exceedance of maximum permissible concentrations of copper, mercury, zinc, manganese, and iron have been recorded at all sampling depths in various seasons and years. The link to the coastline was carried out, the most problematic areas in terms of anthropogenic load were identified. A brief description of each of the metals under consideration is given. The quantitative characteristic of the increased concentrations of certain heavy metals is presented in terms of the MPC multiplicity. Seasonal dynamics of the content of particular metals in sea water during the entire course of the investigation (2000-2019) is shown. Trends and patterns in variations of their concentrations at the present time are assessed. Possible influence of increased content of the aforementioned elements on comfort the habitat of aquatic living organisms is considered.

Purpose. The study is aimed at investigating metal accumulation in the 0–2 cm layer of the bottom sediments of the Black Sea northwestern shelf over 2000–2020, and at identifying the sea bottom areas subjected to the increased anthropogenic load through comprehensive assessment of the degree of their pollution taking into account their granulometric composition. Methods and Results. The bottom sediments were sampled annually from the 0–2 cm depth at the same stations. The detected metal concentrations were compared with their content in the Earth crust and the background values. The dynamics and trends of the individual metals’ content in the shelf bottom sediments were assessed for the whole period of observations. The notion of the average characteristic concentration of an element is introduced; the procedure for its calculation is represented. The pollution of bottom sediments was analyzed with the regard for the element average characteristic concentration in the bottom sediments of various granulometric types. Increase in the average content of lead, zinc and chromium was revealed from the beginning of the observation period to 2020. The seasonal dynamics of these elements was found in the whole water area under study (as well as the iron content at some areas). Conclusions. Multiple cases of the lead, manganese and chrome concentrations exceeding their content in the Earth crust were recorded; as for zinc and copper, such cases were few and sporadic. The tendencies in variation of the bottom sediments content were determined: the average long-term values of the lead concentration increased by 1.2 times, those of zinc – by 1.6 times, and those of chrome – by 2 times; the concentrations of iron, manganese and copper remained essentially the same. Seasonal dynamics of the zinc, chromium, lead and iron content was shown. For a number of metals, the cases when their absolute content exceeded their average characteristic concentration in the corresponding type of the bottom sediments had been found. The regions subjected to a multifaceted anthropogenic load were identified; the areas of possible local inflow of the monitored elements were revealed. The bottom sediments sampled in 2019 were the most polluted.

Purpose. The study is aimed at determining concentrations of the polycyclic aromatic hydrocarbons (PAHs) and at revealing their pattern distribution in the bottom sediments of the "river – sea" contact zone on the example of the Sevastopol Bay and the river Chernaya. Methods and Results. Granulometric composition of the bottom sediments was determined by the decantation and dispersion method. Identification and quantitative determination of PAHs were carried out by the high performance liquid chromatography method. The total PAHs content in the bottom sediments of the area under study varied from 12 to 670 ng/g of dry weight. The pollutant content was minimum in the river site beyond the geochemical barrier. In the area where the river Chernaya flows into the Sevastopol Bay, the PAHs content was 121 ng/g. The highest PAHs content was revealed in the Sevastopol Bay bottom sediments, more precisely, in 1.5 km southwest of the river Chernaya flowing into the bay. 14 PAHs were identified in the estuary zone of the river, 4 of them (naphthalene, 2-methylnaphthalene, fluorene, anthracene) were in the trace amounts. The maximum concentration (99%) of silty material was observed in the Sevastopol Bay water area. The silt fractions were distributed as follows: 20% – aleuritic-pelite fraction, 79% – pelitic-aleurite fraction. Directly in the area of the river inflow into the bay, accumulation of the sand fraction (7%) and the maximum portion of pelitic silts were noted. Conclusions. The recorded values of PAHs corresponded to the natural non-toxic levels. PAHs identified in the bottom sediments of the river estuary zone are of the mixed, predominantly petrogenic origin. The obtained data show that in the conditions of the "river – sea" contact zone, the PAHs accumulation in general and their individual fractions were governed mainly by presence of silt in the bottom sediments.

The contamination level of sea bottom sediments with polycyclic aromatic hydrocarbons in the Balaklava Bay (the Black Sea) was estimated depending on sediments particle size distribution. The total content of these pollutants in the studied water area was averagely 2459,58 ng/g. The increased concentrations of polycyclic aromatic hydrocarbons are confined to the eastern coast and the central part of the bay. Fourteen polyaromatic hydrocarbons were totally identified in 2018, four of which (naphthalene, 2-methylnaphthalene, fluorene, anthracene) had a trace content. Four- and fivecyclic aromatic hydrocarbons made the main contribution to the pollution of sea bottom sediments. In particular, it was chrysene (40,1 %), fluoranthene (17,5 %), benz(b)fluoranthene (15,1 %). The concentration of benz(a)pyrene in bottom sediments of the Balaklava bay ranged from 0,05 - 121,0 ng/g. Its increased concentrations are confined to the central part of the bay in the eastern coast. The amount of polyarenes correlated with the part of silt fraction (0,05 - 0,1 mm)...