New Data on the Concentrations of Polycyclic Aromatic Hydrocarbons in the Sediments in the Coastal Zone of Lake Baikal.

Up-to-date data on the concentrations of priority PAHs in the sediments of Lake Baikal in 2019–2020 have been obtained by HPLC with fluorometric detection. The results of the monitoring of PAHs in the sediments in the areas subject to anthropogenic impact, including discharges of municipal sewage effluents from the city of Baikalsk [wastewater discharges of the former Baikal Pulp and Paper Mill (BPPM)], landfills of the front delta of the Selenga River, and the northern part of the lake adjacent to the Baikal–Amur Mainline (BAM), are presented. The concentration of 15 PAHs in the BPPM region varied from 8.5 to 737.8 ng/g, in the Selenga region, from 23.6 to 218.9 ng/g, and in the BAM region, from 2.2 to 380.8 ng/g. Analysis of the sediment samples from the region of the Small Sea of Baikal was performed for the first time (total PAHs 3.2–121.3 ng/g). The minimum PAH concentrations were found in low organic matter consertal sands. The average concentration of benzo(a)pyrene, as well as other high-molecular-weight PAHs, was approximately 2–5 times higher in the sediments of the Baikalsk region compared to the BAM region and the front delta of the Selenga River. It was found that the PAH profiles in the sediments of the BAM and Selenga landfills were similar to each other and significantly differed from those of the Baikalsk landfill. The study of the origin of PAHs in the sediments showed that most of the samples were of pyrogenic nature. The pyrogenicity indices (∑ PAHs (4-6-nuclear)/total PAHs and ∑ PAHs (5-6-nuclear)/ ∑ PAHs (2–4-nuclear) were higher in the southern Baikal region compared to the delta of the Selenga River, Small Sea, and nothern Baikal. [ABSTRACT FROM AUTHOR]