Abstract
This study is devoted to the assessment of the ecological condition of the Zhaiyk River and provides a comprehensive analysis of the chemical composition of its natural waters. As one of the largest transboundary rivers in Eurasia, the Zhaiyk River has strategic importance for maintaining regional biodiversity and ensuring the sustainable development of adjacent territories. It serves as a crucial source of water for agriculture, industry, and domestic needs of the population in Kazakhstan and neighboring countries. The river’s aquatic ecosystems provide habitats for numerous species of flora and fauna, including valuable commercial fish species. In recent decades, the ecological state of the Zhaiyk River has raised serious concerns due to increasing anthropogenic pressure. The main sources of pollution include industrial discharges, agricultural runoff containing mineral fertilizers and pesticides, as well as urbanization and the growing volume of domestic wastewater. These factors negatively affect surface water quality and the overall condition of the river ecosystem. The study is based on water sampling conducted at various sections along the river, followed by laboratory analysis of key physicochemical parameters. The analyzed indicators include pH levels, concentrations of major ions (calcium, magnesium, sodium, and chlorides), as well as the content of biogenic elements such as nitrates and phosphates. The results indicate an increase in pollution levels, particularly in areas located near industrial and agricultural zones. The study also examines potential ecological risks to aquatic organisms and human health. Based on the findings, recommendations are proposed to improve monitoring systems, promote rational water resource management, and preserve the ecological sustainability of the Zhaiyk River basin.