Changes in the salinity of groundwater and surface water aroundthe decommissioned borehole salt mine “Łężkowice” (S, Poland)
摘要
The borehole salt mine “Łężkowice” extracted salt from 1968 to 1992 from the heavily tectonically disturbed deposit is of Miocene age. Quaternary aquifer overlies the salt deposit. Despite the decommissioning of the mine and the backfilling of goafs, infiltrating rainwater leaches salt and migrates into Quaternary waters, which flow towards the Raba River and result in its local contamination. Surveys conducted in 2010, 2017 and 2024 show no reduction in the intensity of this process. Despite the passage of over 30 years since the decommissioning of the mine and the convergence of backfilled solution chambers, followed by land subsidence, water from the surface continues to infiltrate into the deposit. As a result, Quaternary waters contain 28 to over 10,000 mg/dm3 of chlorides and river water 17–34 mg/dm3. Changes in chloride concentrations at individual points and their spatial distribution are random in nature but coincide with broader directional trends related to the flow of groundwater towards the Raba River. This indicates the need for further monitoring studies until the environmental effects of the solution mining extraction cease.