In the years 1998–2000 the studies were carried out on water, bottom sediments and plant materials collected from the Zegrzyński Lake. Metals (Zn, Cu, Pb, and Cd) were detected in water, in dissolved fractions (hydrated ions, labile and inert complexes), suspended matter and in bottom sediments. The samples of plant parts (roots, stalks and leaves) and molluscs were also analysed. The obtained results showed the best activity (nearly 90%) in metals’ binding registered in suspended matter. A strong power in metals’ binding was shown by molluscs occurring on the bottom of the water reservoir. Taking into consideration plant part, the highest concentration of Zn and Pb were detected in roots and Cu in green parts. The concentration of Zn and Pb were higher in molluscs than in the sediments and roots. Also the concentration of Cd was higher in molluscs than in the bottom sediments and parts of plant parts.