Proceedings of the International scientific and practical conference ―Science at the Frontier of Civilizations: Challenges and Perspectives‖ (December 27-29, 2025) / Publisher website: www.naukainfo.com. – Helsinki, Finland, 2026. – 252 p.

21 ECOLOGY AND ENVIRONMENTAL PROTECTION TECHNOLOGIES UDC 574.587:556.166 Nika Krytska Grade 10-B Student Municipal Institution ―Kharkiv Lyceum No. 100‖, Kharkiv City Council, Ukraine Oksana Pavlenko Biology Teacher Municipal Institution ―Kharkiv Lyceum No. 100‖, Kharkiv City Council, Ukraine Tetiana Zharova English Teacher Municipal Institution ―Kharkiv Lyceum No. 100‖, Kharkiv City Council, Ukraine STUDY OF THE ECOLOGICAL STATUS OFWATER BODIES IN THE SEVERSKY DONETS RIVER BASIN USING SAPROBITY INDICATOR ALGAE Relevance of the problem. Assessment of the ecological status of aquatic ecosystems is one of the key tasks of modern hydrobiology and environmental