Expedition on R/V Akademik Koptyug on June 24-29, 2025

On June 24-29, 2025, the expedition on R/V Akademik Koptyug was carried out within the State Assignment No. 0279-2021-0005 “Study of transformations of the state of water bodies and watercourses of Eastern Siberia in seasonal and long-term aspects in the context of climate change, geological environment and anthropogenic loads” (led by A.P. Fedotov) to the water area of South Baikal and Maloye More Strait.

Together with the Baikal interregional environmental prosecutor's office, the quality of wastewater treatment was checked at WWTP in Kultuk settlement, Slyudyanka town, Baikalsk town, Vydrino settlement and Babushkin town for sanitary-microbiological and chemical indicators. According to the same indicators, the water of the Kultuchnaya, Pokhabikha, Snezhnaya and Mysovka rivers was estimated above and below the discharge of treated wastewater. Samples of coastal waters in the bays of Maloye More in zones with high tourist and recreational load were also taken.

Samples of surface water (0-0.5 m), bottom sediments and hydrobionts (mollusks, amphipods) were taken at 7 stations for further determination by gas chromatographic-mass spectrometry (GC-MS) of persistent organic pollutants (POPs), chlorophenols, parabens, and some drugs. Three net samples were collected at the sites of water blooms caused by cyanobacteria.

In the shallow zone of South Baikal, coal-bearing layers formed about 30-25 million years ago were documented. A well-preserved fragment of a tree trunk was found in one of the layers (see photo).

Also, during the expedition, using the RA-915m mercury analyzer, measurements of gaseous elementary mercury were carried out in the surface layer of the water area of South Baikal and Maloye More. Measurements were carried out every minute, with a mandatory zero check every 10 minutes, which ensured high accuracy and reliability of the data obtained. In total, about 7,000 measurements of gaseous elementary mercury were made during the expedition.