Mine Water and the Environment, Vol. 37, iss. 4 (2018), s. 807-814
A characteristic feature of the mines in the Upper Silesian Coal Basin in southern Poland is their highly saline mine water.
In the past, this water was often discharged into anthropogenic reservoirs located a short distance from the mines, which
completely changed the physicochemical properties of the water. In some cases, it also led to stratification of the reservoir
waters, i.e. to the formation of meromictic water bodies. The Rontok Wielki reservoir, a former fish breeding pond, was
converted into a settling tank for the highly saline (
Cl− = 38,000 mg/L) water discharging from the Silesia Mine. The water in
the tank stratified in three distinct zones: a mixolimnion, chemocline, and monolimnion. The saline mine water input ceased
in 2003 and since then, there has been a gradual decrease in the electrical conductivity and [
Cl−] in the reservoir waters.
Moreover, meromixis has been entirely eliminated and freshwater breeding species have reappeared. A control, the Rontok
reservoir, which was also a breeding pond, but was never used to settle saline mine water, was also studied for comparison.