A method for determination of polychlorinated biphenyls (PCBs) in environmental and biological materials has been developed. This method includes rapid chromatography requiring less than 10 min using an HT-8 capillary column at 30 m × 0.25 mm i.d. Rapid chromatography was performed using a column temperature gradient from 80 to 310°C at a rate of 40°C/min. Low-resolution mass spectrometry in single ion monitoring mode of simultaneous detection of 12 target ions is suggested for detection of PCBs peaks. The method not only enabled us to reduce time of analysis but also to increase the efficiency of separating PCB peaks from interferences and to reduce levels of detection of analytes resulting in a minimized sample preparation stage. The last includes extraction of the PCBs using organic solvents, preliminary alkaline hydrolysis in the case of biological objects, and cleaning up the extracts on compact cartridges. The method was tested in monitoring studies for these contaminants in soils, sediments, snow cover, fish tissues, and seal blubber. Total PCBs and isomer congener groups of the same chlorination degree and seven indicator congeners (IUPAC No.'s 28, 52, 101, 118, 138, 153, and 180) are determined with a high degree of certainty. The PCB concentrations were in the range of 1–700 ng/g dry weight for environmental samples and 500–25000 ng/g lipids for biota. The method yields measurements of total PCBs and isomer groups with a precision no greater than 10% and no greater than 15% for the indicator congeners.

Diatoms are capable of accumulating substantial amounts of triacylglycerides in their cells, which differ in the composition of fatty acids depending on the conditions of cultivation, making them attractive subjects in biotechnology. In the present study, we characterized the structural features of lipid bodies in the diatom Entomoneis cf. paludosa (W. Smith) Reimer strain 8.0727-B and revealed the peculiarities of fatty acid composition in cultures during the stationary and exponential growth phases. Laser scanning confocal microscopy revealed an increased number of lipid bodies in the cytoplasm during the stationary phase of culture growth. Electron microscopy of ultrathin sections showed that an extreme increase in the number and size of plastoglobules in the cells occurs in the stationary phase of culture growth. The gas chromatography with mass spectrometric detection method revealed differences in the fatty acid composition depending on the growth phase. The studied strain can be recommended as a source of hexadecanoic and octadecanoic fatty acids from the culture during the stationary growth phase, as well as eicosapentaenoic fatty acid from the culture during the exponential growth phase.

A number of reports on sponge diseases, including from Lake Baikal, have increased dramatically all over the world in recent years. Herewith, there are various hypotheses for sponge mortality. Lubomirskia baikalensis (phylum Porifera, order Spongillida) is a unique endemic freshwater sponge of Lake Baikal that contains a complex community of eukaryotic and prokaryotic endosymbiotic microorganisms. In this work, we present the first results for the effect of anionic surfactants viz. linear alkylbenzene sulphonates (LAS) at low 10 and 20 µg L⁻¹ concentrations on Baikal sponge species and their symbiotic community as an experimental model. A new toxicity test protocol under conditions close to natural is proposed. It uses the sponge amoebocytes called as SA1-cells, which contain eukaryotic green microalgae Chlorella sp. These SA1-cells are shown to be representative indicator in assessing the impact of anionic surfactants. The acute toxic effect resulted in 97–100% sponge cell death in less than 48 h, as well as 100% symbiotic microalgae Chlorella sp. death over 72 h was noted under LAS solution (20 μg L⁻¹) exposure during in vivo experiments. This includes the cell membrane fatty acid changes, change in the cell sizes, cell swelling, and lysis. Long term exposure to LAS solution (10 μg L⁻¹) reflected in cellular stress (oxidative stress) and accompanied by malondialdehyde formation (0.16–2.0 μg g⁻¹ of dry weight) during 14-day exposure was noted. Oxidative stress and mortality of L. baikalensis are associated with their low antioxidant activity. Trolox-equivalent antioxidant capacity (TEAC) found in the range from 0.00031 to 0.00077 Trolox equivalents for these freshwater sponges.

This paper presents a new technique of hydrocole (bacteria, blue−green algae, phytoplankton, zooplankton, sponges, fish oil and seal fat) fatty acids (FA) methyl esters determination by gas-liquid chromatography. The polyunsaturated fatty acids (PUFA) contents in these objects were different. The distinguishing features of the technique are the next ones: efficiency, lipid extraction recovery ≥94% using the sonication during 10–15 min without sample drying, high PUFAs yield (≥97%) by reduction of oxidation up to 40% during methylation; exhaustive extraction of fatty acid methyl esters (FAMEs) including PUFA; a new approach to obtain of methyl esters of free fatty acids except using toxic reagents; accuracy of FAMEs quantification including ω-3-, ω-6-, ω-9-FA using the di-n-decyl ether as an internal standard and accuracy of measurements using “T14165QC Fish oil” standard sample (first). The technique is approbated for Baikal hydrocole FA determination from 20 to 2000 μg in the sample and might be used for scientific and applied tasks. The interlaboratory precision of FAME determination of phytoplankton and bacteria is ≤10%.

In this study, we present results on fatty acid analysis of phytoplankton of Lake Baikal, the world’s deepest lake, which differs from other lakes by its oceanic features. Since we used a large-mesh net, the net sample phytoplankton were primarily represented by the large elongated diatom Synedra acus. subsp. radians (Kützing) Skabichevskij. The similar algae composition of net samples of spring season phytoplankton collected at different sites of the lake allows us to compare results of the fatty acid analysis of these samples. The phytoplankton diversity of the sedimentation samples was contrary represented by 32 algae species. There are clear changes in the fatty acid composition of net phytoplankton exposed to anthropogenic impacts of varying intensity. The content of polyunsaturated fatty acids in phytoplankton collected from central stations (pelagic stations at a distance of ~10–30 km from the shoreline) without anthropogenic impact was higher by up to 15% than phytoplankton collected from nearshore stations (littoral stations at a distance of ~0.01–0.05 km from the shoreline) and offshore stations (pelagic stations at a distance of ~3 km from the shoreline). The interlaboratory precision of fatty acid determination of phytoplankton is estimated as ≤10%. We found high content of the lipid peroxidation marker (80–340 μg g⁻¹ of dry weight) in phytoplankton from nearshore and offshore stations with intensive anthropogenic impact. In phytoplankton from central stations, we did not find any lipid peroxidation. Determination of unsaturated fatty acids, coupled with analysis of fatty acid peroxidation products, can be used to evaluate the level of anthropogenic impact in terms of ecological health and biodiversity conservation.

Представлены первые результаты по изучению окислительного стресса фитопланктона из озера Байкал и его адаптивных свойств к изменению среды обитания в условиях повышенной антропогенной нагрузки. Анализ фитопланктона, отобранного в поверхностном слое воды (~0.3 м) на прибрежной (глубина 5 м, расстояние от берега 10 м) и пелагической станциях (глубина 543 м, расстояние от берега 1000 м), показал смену доминирующих видов с февраля по июнь 2021 г. В феврале доминировали динофитовые (~40 %), диатомовые (до 33 %) и зеленые (до 12 %) водоросли с низкой биомассой – 100 мг/м³. В марте преобладали золотистые (до 50 %), криптофитовые (до 40 %) и динофитовые (до 30 %) (биомасса 160–270 мг/м³). В апреле наблюдалось увеличение биомассы до 700–3100 мг/м³ с доминированием крупноклеточных динофитовых (до 99 %), золотистых (до 50 %) и криптофитовых (до 35 %) водорослей. К концу первой декады мая доля динофитовых снизилась и увеличилась доля золотистых. Уровень развития диатомовых повышался во второй декаде мая до ~26–38 % при минимальной биомассе фитопланктона (13–30 мг/м³). К июню доля диатомовых в пробах достигала 44–75 % при биомассе 60–550 мг/м³. Окислительный стресс фитопланктона как неспецифическую адаптационную реакцию на длительное, интенсивное либо повторяющееся воздействие стресс-фактора оценивали по содержанию в пробах веществ, вступающих в реакцию с тиобарбитуровой кислотой. Среднее содержание данных веществ – маркеров перекисного окисления липидов – было оценено спектрофотометрически. Окислительный стресс фитопланктона выявлен только в период доминирования в пробах диатомовых водорослей. Это может быть объяснено лучшей адаптацией водорослей других отделов к стресс-фактору. Содержание маркеров перекисного окисления липидов в прибрежном фитопланктоне, отобранном вблизи населенного пункта и крупного туристического центра пос. Листвянка, составило от 100 до 500 мкг/г сухой массы пробы. В 2016 и 2018 гг. в период массового развития диатомовых водорослей обнаружен окислительный стресс фитопланктона вблизи крупных населенных пунктов. В фитопланктоне глубоководных пелагических станций, максимально удаленных от населенных пунктов, стресс не найден. С помощью метода газовой хроматографии показано более низкое (до 15 %) содержание полиненасыщенных жирных кислот в планктоне, характеризующемся наличием стресса. Это свидетельствует о повреждении мембран клеток. Повышенное содержание анионных синтетических поверхностно-активных веществ, а именно алкилбензолсульфонатов натрия, являющихся компонентами моющих средств и вызывающих окислительный стресс гидробионтов, обнаружено в поверхностной воде оз. Байкал (до 30 ± 4 мкг/дм³). Наличие данных соединений в водной экосистеме может приводить к исчерпанию ресурсов фитопланктона, нарушению гомеостаза, стрессу, патологическим изменениям и перестройкам планктонного сообщества.