Zasolenie cieków powierzchniowych wskutek odprowadzania wód odpływowych na Górnym Śląsku

Abstract

SALINITY OF SURFACE FLOWS DUE TO DRAINAGE OF SEWAGE WATERS IN THE UPPER SILESIAN AREASummaryMines are main cause of river salinity in the Upper Silesian area. Other industrial objects and municipal sewages are responsible for a great physical and organic pollution only. The following are rivers characterized by greatest salinity (under conditions of mean flow of the rivers): Kłodnica – 3,1 g/l, Rawa - 2,6 g/l, Bierawka - 2.2 g/l, Brynica – 1,6 g/l, Ruda - 1,5 g/l, Przemsza - 0,8 g/l. These rivers, discharging themselves into the Odra and Vistula Rivers, increase the salt contents of these latter mainly in their upper course. Among ions occurring in the waters the following ones were distinguished: Cl´, Na˙, SO4´´, HCO3´, Mg˙˙, Ca˙˙; they constitute such salts as NaCl, MgSO4, Ca(HCO3)2 and rarely NaSO4, CaCl2, CaSO4 and Mg(HCO3)2. Mine waters mixed with river waters undergo various changes of chemical composition. To the processes taking place during mixing of these waters can, first of all, be referred the process of desulphurization and precipitation of certain salts. The processes of desulphurization take place due to reduction medium developed in the rivers as a result of enrichment of their waters in organic substances brought by industrial land municipal sewages. As a results of reduction of sulphates H2S comes out giving specific smell to some rivers and ion HCO3 is formed giving, together with Ca˙˙ and Mg˙˙ ions occurring in water hardly soluble salts precipitating into the sediment. The processes mentioned above lead to a decrease of SO4´´ ion contents, to the loss of calcium carbonate and magnesium carbonate, i.e. to a decrease of mineralization. Ion Na˙ is probably partly absorbed by gels occurring in waters. To the most stable and invariable ions belongs chlorine; a decrease of its concentration in water can take place only due to dilution.