The influence of waters from hard-coal mines on the hydrochemical relations of Upper Silesian Coal Basin (USCB) rivers

Abstract

Surface waters of the Upper Silesian Coal Basin (USCB) are highly transformed in quality as a consequence of salty minewater discharge to the hydrographic net. These waters drain coal beds which are extracted to a depth of 1000 m. The amount of minewater, discharging directly or indirectly to the river net of the USCB reaches 8-9 m3/s with a variability in particular years of 1-1.5 m3/s, which depends on hydrological conditions of the levels extracted. In 1994, the salt load introduced together with these waters to the Vistula and the Oder reached 6793 tons per 24 hours of chloride ions and 1351 tons per 24 hours of sulphate ions. This accounted for over 50% of the chlorides and about 35% of the sulphates discharged to surface waters in the country. Furthermore, a part of the minewater also contains radioactive elements (radium22 ). The chance to improve the quality of the Oder and Vistula waters in the nearest future is meagre.