Аннотация
This study presents a multicomponent assessment of pollution and the ecological status of surface waters in the Brazhinsky Stream, located within the city of Ust-Kamenogorsk (Eastern Kazakhstan). The assessment is based on the analysis of water turbidity and hydrochemical composition. The results show that turbidity values range from 47.7 to 54.3 NTU, indicating a high content of suspended solids and their significant role in the transport of pollutants. Hydrochemical analysis revealed persistent exceedances of maximum permissible concentrations for several elements, with copper, zinc, aluminum, and iron making the greatest contribution to overall contamination. Copper concentrations reach up to 44.2 times the permissible limit, while zinc concentrations are as high as 9.8 times the allowable level, indicating pronounced anthropogenic impact. An integrated assessment of water quality was carried out using the Water Pollution Index (WPI), with values of 2.27, 2.75, and 3.68 recorded for the upper, middle, and lower sections of the stream, respectively. According to the classification scheme, these values correspond to the category of “polluted water,” with a clear trend of increasing contamination downstream. It is shown that the Brazhinsky Stream, despite not directly discharging into the Irtysh River, plays an important role in the redistribution of pollutants within the system of surface and groundwater. The findings indicate a significant anthropogenic load on the watercourse and highlight the need for regular hydrochemical monitoring of small streams in urbanized areas.