In first experiments different model systems with the two basic components, clay minerals and bacteria, were used to study the Cu-adsorption on the organic and inorganic components of river-suspended matter separately and in their combination. The formation of the floc structure, typical of river-suspended matter, developed owing to the bacteria overgrowth on the surface of the clay minerals and the following production of extracellular polymer substances (EPS). Higher protein and carbohydrate contents for the systems with the components of clay minerals and bacteria combined document a higher bioproduction than in the system with only bacteria. After 72 h the Cu quantity of the suspended matter flocs is at least twice as high as in the system only with bacteria. It proves the supporting effect of the clay minerals on the bioproduction as well as the dominant part of the organic matter as main pollutant adsorber in river systems.