This work aims to study the distribution features of eight potentially toxic heavy metals (Cd, Pb, Co, Cu, Ni, Zn, Cr, and Mn) and two biogenic elements (N and P) in the bottom sediments of beaver ponds in two small rivers of the Volga Upland’s far north of the East European Plain. In 27 most typical beaver ponds, differing in their morphometric characteristics, as well as in some sections of the studied rivers unaffected by beaver activity, bottom sediments were collected in their upper, middle and lower reaches. The content of heavy metals and biogenic elements in the rivers’ water was also determined. The obtained results were processed using statistical methods. The concentration of mobile forms of Co, Cu, Ni, and Mn in the sampled sediments significantly exceeds their concentration in the soils of basin areas and in the sediments of riverbeds not affected by beavers. At the same time, the content of total Cd, Zn, and Mn, as well as N and P in the sediments of the upper reaches of the rivers is somewhat higher than in their lower reaches. The distribution of gross forms of heavy metals is significantly affected by the granulometric composition of bottom sediments and the content of organic matter in them. Statistically significant factors influencing the presence of mobile forms are the distance from the river mouth, the length of beaver dams and ponds, and the content of organic matter in bottom sediments. The distribution of biogenic elements correlates well with the height and length of beaver dams, the distance from the river mouth, and the content of organic matter in the sediments. It was revealed that the bottom sediments of beaver ponds of the studied rivers are not contaminated with either gross or mobile forms of the studied chemical elements. For mobile forms, a moderate enrichment of Pb, Co, and Ni was found. Of all the analyzed heavy metals in the bottom sediments, compared with sections of the riverbed unaffected by beaver activity, an excess was observed only for Co, Cu, Ni, and Mn.
The article represents the results of study of an exceptional collection of coprolites recovered at the Serteya II and Duborkay V wetland settlements (Dnieper-Dvina region, NW Russia), assigned to ca. 4200 − 2200 cal BC. The research summarizes results of paleoparasitological analysis, micro computed tomography, macroremains, faunal analysis and spatial investigation. This whole set is regarded diachronically to address seasonality of sites occupation by local hunter-fisher-gatherers groups, their dietary patterns, and a range of zoonotic parasite infections for specific time periods and within a wider cultural and chronological frame. Given scarcity of human remains in this region, coprolites serve as a proxy for understanding human diet and pathogens in a diachronic way. It can also be testified by the results of isotopic analysis and faunal remains that show an important role played by fish procurement in the life of ancient people that inhabited this area during the 4th -3rd mill BC. The change in the occurrence of the parasites might have been an indication of cultural changes recorded for the time period from the 4th mill BC till the 1st mill BC connected with changes in food range or cooking techniques.
Self-organization, pH, specific electrical conductivity, surface tension, and UV absorption and fluorescence spectra of dilute water—ethanol—estrone solutions (series 1) and water—ethanol (series 2) were studied. A relationship was established between the reorganization of the dispersed phase, non-monotonic changes in the physicochemical properties, fluorescence intensity (λex 230 nm, λem 340 nm), which occur as the systems of series 1 were diluted, and their toxic and harmful effects on the abundance of green algae Chlorella vulgaris and mortality of cladocerans Ceriodaphnia affinis. The highest impact on the hydrobionts was observed in the vicinity of the calculated concentrations of estrone where the most pronounced changes in the size of the dispersed phase, fluorescence intensity, and physicochemical properties were detected. No relationship between structure formation, properties, and bioeffects was observed in dilute solutions of series 2, which are less prone to self-organization and impact on the hydrobionts.
Metals phytotoxicity assessment in soils is predominantly based on laboratory testing. In this paper, we evaluated the effect of the duration of laboratory testing on copper toxicity levels, in ryegrass (Lolium perenne L.) grown in soils polluted by copper mining. Laboratory testing was carried out according to the protocols of ISO 11269-2, 2012 (for 21 days) and ISO 22 030, 2005 (for 60 days). When tested for 21 days, the soil copper content had no statistically significant effect on plant growth or on the ryegrass shoot copper content. Conversely, when tested for 60 days, plant growth was inversely proportional to the total soil copper content and to the soil exchangeable copper concentration. Therefore, short-term testing underestimated copper phytotoxicity. The results of this study demonstrate that long-term laboratory testing is required to realistically predict metal toxicity in plants grown under the real conditions of natural and agricultural ecosystems.
This article presents an overview of the All-Russian scientific conference with international participation, «Gabdulla Tukay: Commemorative Practice in the Context of State Policy and Public Initiatives», dedicated to the 140th anniversary of the poet's birth (Kazan, April 2, 2026). The author analyzes the papers presented during the section, which included scholars from the Marjani Institute of History of the Tatarstan Academy of Sciences.
