The results of the first (since 1939) hydrochemical investigations of Gliwice Channel have been presented. The polluted K.lodnica River affects bad water quality of the canal. For example the concentrations of chlorides (Cl), sulfates (S04), sodium (Na), potassium (K), conductivity and dissolved substances quality of water is out of standards. In the case of BOD and COD the water quality is changed from out of classes to II class. pH and oxygen concentration are in I class. Although no salinity waters flow into the canal, the water quality get improved slightly only. The decrease of pollutants concentration is related to theirs dispersion. In the case of water quality the self-purification processes are of secondary importance.

Results of the study presented in this article and earlier have been the first ones since the Gliwice Canal was put into service in 1939. Until now there have been no investigations concernig (the Canal state in the area of hydro-chemical study), sanitary state or level of sediment contamination. The aim of this study was therefore to obtain information about the current pollution. The level of aquatic environment in some reaches of Gliwice Channel. This article presents the results of investigations carried out in order to assess of water quality in the Canal relating to nitrogen and phosphorus compounds. The following nutrients were determined in water samples ammonia, nitrite and nitrate nitrogen as well as organic dissolved and organic suspended nitrogen. In addition concentrations of orthophosphates, polyphosphates and organic phosphorus were analyzed. The analyses were carried out in water samples taken in six samplings from January till June 2000. Water samples were drawn at 7 sampling points. Samples of bottom sediments were taken at 21 sample points. Basing on the results of analyses the water quality of Gliwice Canal has been determined. A classification of chemical parameters was carried out under the provision in force. Basing on this classification we can state that water in the Canal is does not quality for any class system. We can also affirm that the water quality on the whole length of Gliwice Canal has improved only slightly even though waters of lower pollution levels supply the Canal.

This study includes hydrologie characteristics of the Potok Toszecki basin area and the results of chemical analysis of water quality of the Potok Toszecki. These investigations were carried out in following periods: from March 1993 till May 1994 and from January 1997 till June 1998. The results of investigations on the chemical parameters of water quality were compared with analysis, carried out in 1976. Under the results of this investigations water quality of the Potok Toszecki - a watercourse, which flows to the Pławniowice Reservoir - was defined and essential factors, connected with character of the basin area have been shown. Classification of several parameters was achieved under the official decree of the ministry of environmental protection from November 5th 1991. On the basis of this classification it was found, that the main risk for the Pławniowice Reservoir are biogenie substances and suspension, inflowing to the Reservoir together with the water of the Potok Toszecki. Improvement of the existing situation will be possible only if firm waste-water managements action will be taken.

In the presented work the limnological characteristics of the Reservoir Nakło-Chechło elaborated on the basis of investigations carried out in 1996 has been shown. The results of investigations on thermal and oxygenic conditions existing in the Reservoir and the change dynamics of selected physico-chemical indicators of water quality in the Reservoir Nakło-Chechło are described. The paper describes aspecific example of acidotrophy of the Nakło-Chechło Reservoir as a result of anthropopressure. The results of chemical analysis of water in the Nakło-Chechło Reservoir and evaluation of the dynamic changes of various indicators with the atmospheric precipitation quantity on the basin superficies have shown that the Reservoir is under strong hydrological and chemical influence of the precipitation, which generally is acidic and has a very low total hardness. The exceptional vulnerability for acidification due to deficiency in water buffering capacity was, however, the decisive factor. The discharged weak buffering capacity of the Reservoir water facilitates the influence of direct precipitation and through superficial run off. The results of chemical analysis show high state of water quality in the Reservoir Nakło-Chechło as regards amount of indicators which describe water mineralization degree.