Characteristics of the chemical composition of water in reservoirs under the influence of coal mine waste in the Upper Silesian Coal Basin (southern Poland)

This article presents research results on the water chemistry of 16 reservoirs adjacent to post-mining waste landfills in the Upper Silesian Coal Basin, sampled in 2022 and 2023. The waters of these reservoirs are anthropogenically modified; in terms of hydrochemical type, they are multi-ionic waters. The Comprehensive Pollution Index (CPI) was also used to assess the degree of water pollution. Calculations indicated that the waters are either moderately (0.47 < CPI < 1.92) or heavily polluted (CPI > 2). Research has also shown that areas reclaimed with mining waste are informal post-mining waste dumps and should be treated as potential sources of groundwater pollution. In nearby reservoirs, there is a potential threat to shallow (0-10 m) groundwater of the first aquifer, which is especially important when the first aquifer is being used.