Abstract
The article discusses the problems of pollution of the Ertis River in the Kazakhstani part of the basin. The data on the quality of river water obtained in the period from 2012 to 2023, which is generally characterized as unsatisfactory, was analyzed. The main sources of river pollution are discharges of industrial and municipal wastewater in the Bukhtarma, Ulba, Ertis river basins, and there is also a trans-boundary impact. As a result of the activities of a number of industrial complexes in the studied area, increased concentrations of heavy metals (lead, copper, zinc, and cadmium), nutrients (iron), and suspended particles (11.9–28.3 mg/dm3) are observed in the water of the Ertis River. The most polluted sections of the river are in the areas of Ust-Kamenogorsk, Semipalatinsk and Pavlodar. To improve the water quality of the Ertis River, it is necessary to take measures to reduce trans-boundary discharges of pollutants, ensure effective treatment of industrial and municipal wastewater, and also monitor the quality of the river’s water in order to track the dynamics of pollution and take timely measures to reduce it.