Impact of anthropogenic factors on the potable groundwater chemistry in the Upper Silesia Coal Basin (USCB)

The Upper Silesia urban-industrial region is one of the most industrialized areas in Europe, due to a concentration of mineral deposits, including hard coal, zinc and lead ores and other raw materials. Ground-water is pumped by wells and discharged by mines. Potable groundwater in this area occurs within the Neogene, Cretaceous, Triassic (over 60% of the groundwater resources) and Carboniferous formations. Within these formations, 16 major aquifers fit the quantitative and qualitative criteria proposed by Kleczkowski (1990) and extend over the total area of about 3257 km 2). Within the Pleistocene formation, nine major aquifers of porous character have been identified. They are situated in the areas of buried valleys and modern river valleys. The TDS content ranges from 47 to 1374 mg/L. More than 80% of samples represent quality classes II and III in the four-class scale of water quality, because of urban and industrial impacts. Within the Triassic carbonate forma-tion, five major aquifers have been identified in fractured–karstic–porous dolomites and limestones. This water-bearing complex is overlain partly by impermeable Keuper clays and by permeable Holocene and Pleistocene sediments. The TDS values vary from 103 to 1519 mg/L. Generally groundwater in the Triassic aquifers is of a better quality (classes I and II). Poor quality water (classes III and IV) occurs only within Zn–Pb ore mining areas and in the areas impacted by urban agglomerations. The groundwater occurring in Carboniferous sandstones is generally of poor quality due to mining impact. Therefore, no major aquifers have been distinguished in the Carboniferous strata