Regionalne zróżnicowanie geosystemów zlewni rzecznych środkowowschodniej Polski w świetle badań odpływu roztworów

The diversity of solute flow was determined according to 1981-2000 data, taking into account environmental factors. The water assessment was based on analysis results from 19 rivers in the area between the Wisła and Bug rivers (Fig. 1). Based on average annual values of six parameters (general mineralisation in the form of dry residue, concentrations of dissolved oxygen and of chloride, phosphate and ammonia nitrogen ions as well as the amount of organie compounds - BOD₅), pollution indices were determined, enabling the classification of the river basins analysed according to a five-degree pollution scale (the first degree being "clean" rivers and the fifth degree denoting "critically polluted" rivers). A comparison of study results from the 1991-2000 period to the corresponding data from the 1981-1990 period indicates a trend towards the improvement of water purity in rivers. The results achieved show that in most areas of the Lublin Region rivers drain basins that exhibit high environmental values ("clean" and "slightly polluted" basins) and low levels of the environmental burden caused by economic activity. Solute flow from those basins depends on geological and hydrological conditions (Fig, 2, Fig. 3). Approximately 80-85% of the solute flow from those basins account for the chemical denudation of the lithosphere.