In the ecological system of the Mściwojów Reservoir the occurrence of heavy metals was ascertained. The concentration of chosen elements: in bottom sediments of the reservoir (Cu, Zn, Pb, Cd, Ni, Mn, Fe) and in the reed (Phragmites australis) from settlement ponds and the pre-dam reservoir (Cu, Zn, Pb, Cd) has been determined. Origin of these metals can be both geogenic and anthropogenic. In the paper the possibility of the element genesis has been presented. Accordingly, there has been analyzed the geological formation of the reservoir catchment and collected the information on agricultural and communal pollutions.. Anthropogenic hazard for the water environment on this area originates mostly from the agricultural space, as a consequence of applying the intensive agriculture, the mineral manures and the plant protection measures and the irrational leadership water-of sewer management. ...