2949775638

GEOGRAPHIA POLONICA 68, 1997

STRUCTURE OF THE SOLUTE YIELD IN THE VISTULA RIVER BASIN WITH SPECIAL REGARD TO ANTHROPOGENIC

COMPONENTS

Henryk Maruszczak, Maria Wilgat

Department of Physical Geography and Paleogeography, Maria Curie-Skłodowska University

Akademicka 19, 20-033 Lublin, Poland

ABSTRACT: On the basis of data concerning smali catchments not polluted by municipal and industrial sewage we calculated the solute yield from rural areas. Calculations were carried out in a simplified way, taking into consideration the mean solute concentrations from data for the years 1976—1985, and mean discharges of river waters. For 20 selected larger catchments of the Vistula tributaries we also calculated the total solute yield, i.e. including the sources of municipal and industrial wastewater. On the basis of these and other data we attempted to analyse the balance of the solute yield. Components taken into account come from: precipitation, agricultural Chemicals, farm sewage, municipal and industrial wastewater, and Chemical denudation of the lithosphere. Results were considered in relation to regional differentiation. Essential changes in the solute yield structure were also noted in comparison with the period of the 1930’s.

KEY WORDS: anthropogenic impact, Chemical denudation, municipal and industrial wasterwater, solute concentration and yield, Yistula River, Eastem Poland.

INTRODUCTION

In natural conditions the dissolved load transported by rivers comes mainly from Chemical denudation of the lithosphere, i.e. from soils and their bedrocks; a minimal part comes from the atmosphere in precipitation. As land use is morę and morę intensive a bigger role is played by anthropogenic components, i.e. man-made (synthetic) substances.

An analysis of the hydrometrie data illustrating the total concentration of substances dissolved in river waters and their Chemical composition is the basis for quantitative estimation of the percentage of components of different origin. In Poland investigations of this kind have been carried out mainly in smaller, subordinate catchments. For example, J. Wilamski and Z. Śliwa (1978) tried to calculate the percentage of components coming from soil fertilization in the total solute yield from the catchments of Przymorze.