This paper describes the study of the fatty acid (FA) composition of three fish species (roach, perch, and pike) from Lake Gusinoe (western Transbaikalia). Using principal component analysis, the fatty acid composition of the studied fish species was shown to be species specific. The muscle tissue of roach, perch, and pike was found to contain high levels of polyunsaturated fatty acids (PUFA), including essential docosahexaenoic (DHA), eicosapentaenoic (EPA), and arachidonic acids. Indicators of nutritional quality based on the fatty acid composition showed that the values of the hypocholesterolemic/hypercholesterolemic (HH) ratio indices were sufficiently high. The atherogenicity (AI) and thrombogenicity (TI) indices, which are indicators for the nutritional value, were less than 1 in the studied fish. In terms of flesh lipid quality (FLQ), pike and perch had the highest proportion of total EPA + DHA. According to the obtained data for the composition of fatty acids in the muscle tissue of the studied fish from Lake Gusinoe, the anthropogenic load exerted on Lake Gusinoe has not yet statistically significantly affected the fish muscle quality.

The essential oils and lipid fraction extracted from the aerial parts of Bupleurum scorzonerifolium were determined by a GC-MS method. In total, up to 67 components were identified. cis-β-Ocimene, trans-β-ocimene, limonene, α-pinene, α-copaene, β-elemene, and caryophyllene oxide were recognized as consistent components of the essential oil extracted from the aerial parts of B. scorzonerifolium, regardless of the habitat. The content of these components varied from traces to a significant amount. The volume of the lipid fraction varied from 2.73 to 9.38%. In total, 23 components were identified, including 20 fatty acids, two sterols, and one ketone. The major fatty acid components identified were 16:0, 18:2n9, and 18:1n9. The total content of these fatty acids reached up to 76.19%. The lipid fraction of the aerial parts of B. scorzonerifolium predominantly contained MUFA and PUFA, which confirmed the pharmacological value of the species. The main factors affecting the composition of essential oils and lipid fractions of B. scorzonerifolium are environmental ones that determine the moisture supply to the plants in semiarid and arid areas.

The increasing consumption of phthalates (PAEs), along with their high toxicity and high mobility, poses a threat to the environment. This study presents initial data on the contents of six priority PAEs in the water of lakes located on the eastern shore of Lake Baikal-Arangatui, Bormashevoe, Dukhovoe, Kotokel, and Shchuchye. The mean total concentrations of the six PAEs in lakes Arangatui and Bormashevoe (low anthropogenic load) were comparable to those in Kotokel (medium anthropogenic load, 17.34 µg/L) but were significantly higher (p < 0.05) than in Dukhovoe and Shchuchye (high anthropogenic load, 10.49 and 2.30 µg/L, respectively). DBP and DEHP were the main PAEs in all samples. The DEHP content in lakes Arangatui and Bormashevoe was quite high, and at some sampling sites it exceeded the MACs established by Russian, U.S. EPA, and WHO regulations. The assessment showed that there is no potential risk to humans associated with the presence of PAEs in drinking water. However, the levels of DEHP, DBP, and DnOP in the water pose a potential threat to sensitive aquatic organisms, as shown by the calculated risk quotients (RQs). It is assumed that the origin of the phthalates in the studied lakes is both anthropogenic and biogenic.

Fresh water scarcity is considered a significant component, and potentially one of the most critical, of global climate change. With the rapid development of industry, there is an increasing risk of freshwater contamination by heavy metals (HMs). The danger of HM pollution is also attributed to their accumulation, which can subsequently become a source of secondary pollution in aquatic environments. In the Lake Gusinoe basin, located in Russia, concentrations of HMs were measured in both water and bottom sediments within the lake area, as well as in inflowing and outflowing watercourses. Ecological risk indices were also calculated for the Gusinoe basin. Our results showed that the average concentrations of Fe, Zn, Cr, Ni, Cd, and Pb in the water did not exceed the maximum allowable concentrations (MACs) set by Russian national standards and WHO standards, while the concentrations of Mn and Cu exceeded the corresponding MACs during winter, spring, and autumn possibly due to decomposition of aquatic vegetation and influx from groundwater sources. The average concentrations of the investigated HMs in the BSs did not exceed the background values. The water hazard index indicated a low risk for all samples in the lake water area. For all BS samples, the geoaccumulation index (Igeo) and the Pollution Load Index (PLI) indicated low pollution levels, while the values of the Enrichment Factor (EF) and the Contamination Factor (CF) indicated moderate pollution in the central part of the lake. The Ecological Risk Factor (Er) for Cu in BSs at points near major settlements and in the Tel River indicated moderate pollution. The Potential Ecological Risk Index (RI) in all investigated BS samples indicated a low risk of contamination.