Variability of toxic pollution of the Neglinka river in Petrozavodsk in summer

The article discusses an actual problem of surface water pollution. The aim of the work is to assess the influence of a variable urban environment on the elemental composition of river water. To achieve this goal, river water samples were taken in the lower reaches of the small Neglinka River, which flows through the territory of the town of Petrozavodsk and runs into the Onega Lake. Samples were taken on the same day (06. 19. 2023) before and after a short-term rainfall. Thereupon concentrations of 30 elements determined by the ICP-MS method were studied. These elements are most typical of an urbanized area and are important for its environmental assessment. The concentrations of 26 elements were compared with the regional background. The results indicate the pollution of river waters in urban conditions. The average concentrations of elements in dry weather exceeded the regional background: U (20.4–27.5 times), Mg (10.9–13.5), Na (11.4–11.7), Sr (6.7–6.9), Cu (6.4–6.5), Mo (6.0–6.6), Sb (5.8–6.5 and up to 7.3), Ba (5.0–5.2 and up to 7.4), Ca (4.8–5.3), K (4.4–4.9), Cd (4.0–5.8), Cr (3.9–5.1), P (3.6–5.1), Li (3.2–4.0), Ni (3.1–3.2), Co (2.2–2.6), Mn (1.9–3.2), etc. Background concentrations were not exceeded for Th and Fe. Different distribution of concentrations in river water at different sites was noted for a number of elements. The highest ratio of the maximum concentration to the minimum one was recorded for W (Cmax/Cmin = 7.5). A sharp increase in concentrations of Ti, Th, Zn, V, Ag, Sn, W, Co, Cr, Cu, Fe, Mn, Pb, Sb, Ni, etc. was found after rainfall, as well as a decrease in Mg, Ca, Na, Sr and U. The results obtained are important for understanding the ecological and geochemical relationships within a natural-anthropogenic geosystem, as well as for environmental decisions-making.