Summary:

As natural river-courses, according to the Act on Water Law (Dz.U. 2005.239.2019 (U)), are recognized: rivers, streams, brooks or other waters, flowing continually or periodically, in their natural river-beds. Urbanized water–courses, in turn, constitute streams and brooks, of draining character, within city areas (Osmulska- Mróz, 1990). Their average daily rate of flow is not higher than 1,5 m³/s, and maximum ratio of breadth to depth equals 20:1. The urbanized water courses, often with developed small retention, as a consequence of urbanization, either disappear or become sewers (open or partly covered), transporting pollutions to the greater rivers 169 or water regions. Within their catchments, particularly, takes place the accumulation of heavy metals in bottom sediments. The latter process combined with eutrophisation and increased salinity, causes degradation of ecological potential and extinction of sensitive species of water plants. The Prądnik–Białucha River is an example of such water-courses. In order to assess the quality of water, its pH, EC, Eh and heavy metal contents in water, water suspension matter and bottom sediments, have been determined. The concentration of anions: chloride, sulfate, nitrate and phosphate have also been analyzed. The results obtained were referred to the standards obligatory in Poland and in EU. The area of the river–bed has been inspected in terms of sources of pollution (quantities and sensitivity to stress makers) and occurring of water plants in conditions ecologically difficult.