Abstract
The article provides an overview of anthropogenic factors negatively affecting the geosystems of the Ilek River basin. The accumulation of chemical elements and their introduction into the environment result from human industrial and agricultural activities. The article examines natural and anthropogenic causes that adversely impact the qualitative composition of surface waters in the Ilek River basin. It also considers the hydrological regime of the Ilek River and its major tributaries based on field observations conducted in 2024. The study identifies natural and anthropogenic factors that have been influencing the geosystems of the Ilek River basin for decades. Results of chemical analyses of surface water samples from key sites demonstrate a clear correlation with elements of the technosphere. It has been established that first- and second-order tributaries of the Ilek River, located in the northeastern part of the basin, are polluted with heavy metals due to mining and geological exploration activities. The Water Pollution Index (WPI) was calculated for the Ilek River and its major tributaries. The findings indicate that while the water bodies of Aktobe oblast, which remain underresearched, generally meet surface water quality standards, the surface waters in the middle reaches of the Ilek River are classified as highly polluted. This highlights the necessity for more comprehensive investigations to prevent further deterioration and to develop measures for reducing pollution levels.