Аңдатпа
The present article considered a question about the self-treatment capacity of lakes, rivers and reservoirs in Akmola region based on oxygen indices. Furthermore, this study shows the influence of individual hydro-chemical indicators (sulfates, chlorides, magnesium, ammonium salt, nitrogen nitrite, fluorides, common iron, zinc, manganese, copper) on self-treatment capacity of water bodies. The self-treatment capacity of reservoirs in Akmola region was assessed based on oxygen parameters such as the amount of dissolved oxygen in water and the biological oxygen demand (BOD5). Rivers and lakes were divided into six classes of self-treatment ability. In addition, we studied the associated hydro-chemical components that can have impact on the purification potential of water in lakes and rivers. The results of research showed that the increased content of ammonium salt, nitrogen nitrite, total iron and copper suppress the self-treatmentcapacity of water. The majority of studied reservoirs by annual average indices have low self-treatment capacity. It was determined that the excess of the individual hydro-chemical components and the number of exceeding components with synergis-tic effect could have effect on the self-treatment capacity of water.