Influence of Hard Coal Mine on Water Quality in the Vistula River

The subject of the paper was determining the effect of supplied mine waters on the quality of the analyzed section of the Vistula River. “Silesia” Mine Enterprise (ME) which supplies the pollutants is situated in the southeastern part of the Śląskie province. Silesia ME extracts hard coal and mine gas – methane. The mine belongs to medium waterlogged mines with chloride-sodium inflowing waters. Before their discharge to the river, the mine waters are as a whole drained to the storage-dosing reservoir. Beside the retention and dosing mine waters to the Vistula River, the reservoir allows for removing the mechanical suspension from the waters.The main point of the work was acquisition of samples for analysis. Water samples were collected in 2011 from four control and measurement points along a kilometer section of the Vistula river and used for laboratory analyses. The control and measurement points were situated 20m above the discharge ditch outlet to the Vistula River and subsequently 50 and 1000 m below the discharge. The following parameters were measured immediately after water sampling: water temperature, the contents of dissolved oxygen, oxygenation capacity, pH and electrolytic conductivity. The other eighteen components were analyzed in a laboratory. Determined were: the content of total suspended solids, dissolved substances, sulphates, phosphates, total phosphorus, ammonium nitrogen, nitrite nitrogen, nitrites, nitrate nitrogen, nitrates, ammonium ion, chlorides, sodium, calcium, magnesium, total iron, potassium and manganese. The paper assessed the dynamics of water physicochemical indices, fulfilling conditions at supplying polluted water to the receiving water and functional values of water. It was stated that the Vistula waters deteriorate after introducing mine waters. They become waters below the good state, creating conditions unsuitable for fish life and unfit for water supply to people. Pollution of mine waters, regarded as treated sewage, exceeds the permissible values of some indices as stated in legal regulations. However, the key concentration of chlorides at the point of full mixing does not exceed their permissible values. River self-purification is on a good level, since mostly pollutant concentrations decrease on the length of the investigated section of the Vistula River, i.e. in point 4