ASSESSMENT OF THE TENDENCIES OF CHANGES IN THE PURITY LEVEL OF SURFACE WATER AND GROUNDWATER. Janusz Burchard, Postgraduate Study of Formation and Environmental Protection, Łódź University, Łódź, Poland.

The article presents the technique that enables the changes in the surface water and groundwater purity to be determined. Practical attempts to apply this method (the Wz contamination coefficient) have shown its value in spatial and temporal assessment of the tendencies of changes in the water quality. The coefficients of water contamination (Wz) and water purity (Wzch) are used to analyse the space and time changes of water quality in the rivers Ner and Warta, as well as of groundwater in various regions of Poland. A multigrade scale used to assess a degree of changes of the river water and groundwater purity was essentially improved.