Contamination of small urban watercourses on the example of a stream in Krakow (Poland)

Abstract

The urbanization of catchments is consistently accompanied by a decrease of the stream condition. The case study concerns one of the urban streams in Krakow (Poland). The aim was to show the pollutant load which can enter the Vistula River from even a very small inflow. Samples of water, suspended particulate matter and bottom sediment were collected. Values of pH, Eh and electrolytic conductivity were measured in situ and the contents of macroelements—cations and inorganic anions—as well as trace elements were analysed by means of different instrumental methods. The results obtained are related to normative values, geochemical background and different classifications. The exceedance of permissible values for water by electrical conductivity, calcium, chlorides and cadmium concentrations in all of the sampling locations was stated. The high content of heavy metals in the bottom sediment was found especially for zinc (to 929 mg/kg), lead (to 131 mg/kg) and cadmium (to 10 mg/kg). It is shown that pollutants carried along with the waters and sediments of the stream constitute a continuous source of pollution of the Vistula River. It seems important to measure the concentration of some elements not only in the sediment of the biggest rivers but also in the smaller streams, ditches and rain collectors. Only management in the entire catchment system and inventory of pollution sources can give some positive results in improving the quality of urban watercourses.