Аннотация:The change in the distribution of Cu compounds by size fractions with an increase in its concentration in noncontaminated surface waters has been studied experimentally. It has been shown that dissolved organic substances in natural waters, especially humic substances, have a significant influence on the formsof Cu occurrence at a high content (up to 50 mg/L), determining the stability of its colloidal compounds. In surface waters with a low content of organic matter that are contaminated with copper, high-molecular Cu compounds will be formed, which can lead to the removal of Cu into the bottom sediments.