Contamination of the Kondopoga Bay and tributaries of Lake Onego with dibutyl phthalate (DBP), the most widespread and industrially used phthalic acid ester, was assessed. The water samples were analyzed for the content of organic substances, biogenic elements, heavy metals and the ionic composition of water, as well as lignosulfonates. The DBP concentration was measured using gas chromatography and mass spectrometry. Sampling was conducted during the period of ice formation in March 2023, in the water area of Kondopoga Bay, Lake Onego. This area was affected by wastewater discharges from the Kondopoga PPM. Samples were also collected in several small rivers near Petrozavodsk, receiving runoff from residential areas and landfills. In all analyzed samples, the DBP concentration exceeds the MAC for fishery reservoirs (1 microgram/l)). At the same time, there were no statistically significant correlations between the content of DBP and the marker components of wastewater (lignosulfonates and biogenic elements). However, statistically significant correlations between DBP concentration and the content of lithophilic elements (Fe, Mn, Si) as well as organic substances of natural origin (in terms of color, total organic carbon, dissolved organic carbon, and COD) were found, which suggests their joint intake from the catchment area. Thus, it has been revealed that the Kondopoga PPM does not significantly affect the content of DBP in the Kondopoga Bay of Lake Onego, and its sources of entry into the lake are mainly atmospheric precipitation, surface and river runoff. The increased DBP content in organic-rich river waters of the boreal zone may partially be of natural origin. The contamination of Lake Onego and its small tributaries, as identified in this study, is comparable to that of previously studied reservoirs in Russia and other countries.
M.B. Zobkov (Wed,) studied this question.