Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

94Sample no. 11 taken from the outflow canal ofthe old sludge basin of „Čučma“ in the cadastralarea of Rožňava does not meet the requirements ofthe valid standards due to higher contents of Fe andMg as well as the higher contents of Sb and As.Results in Tab. 1 and 2 prove that sources ofhigh contents of some selected elements (Fe, Mg,Mn, Zn, Cu, Co, Ni and As) are outflows of watersfrom old mining shafts and drifts, mining sludgebeds and dumps. After the water has flown fromthe contamination source it is often largely dillutedas soon as it flows to the surface stream or the riverSlaná. That is why the contents of the selected elementsin the samples from localities of the surfacestreams are lower than the limit values of the validstandard (2) for water in surface streams.The basin of Slaná is special due to the fact thatthe water in the water reservoir of WW Vlčia Dolinaand the water reservoir in Dobšiná (Fig. 1 and 2)that is the balancing reservoir is in fact the waterfrom the basin of Hnilec. It is caused by the factthat the pump-storage power station in Vlčia Dolinabeing an integral part of the water reservoir ofWW Vlčia Dolina generates the electrical energyusing the energy of water brought by pressure pipingfrom the water reservoir of WW PalcmanskáMaša in the basin of Hnilec. In the basin of Hnilecabove the water reservoir of WW PalcmanskáMaša up to the spring of the river of Hnilec thereare old abandoned mining works and places ofprocessing of extracted ores up to the final product– metal having the area of 84.5 km 2 .Due to the transfer of water from the basinof Hnilec to the basin of Slaná through the abovepressure piping there have been assessments of waterquality made in the 3 water reservoirs of the waterworks.The third water reservoir is in, or bettersunder Dobšiná town (Fig. 2), since 1956 focusingon the water management point of view. What isassessed is the quality of water. Results of chemicalanalyses are not published.Brief characteristics of this water reservoir(4) say that there is water accumulated having thecharacteristics corresponding to the water qualityof lower horizons in the water reservoir of WWPalcmanská Maša. The basic chemical structureexcluding the concentration of the total Mn and Fecorresponds with the chemical composition of theFig. 2 General chart of drainage basins of Hnilec and Slaná Rivers in the territory of cross connection of waterreservoir of WW Palcmanská Maša and water reservoir of WW Vlčia Dolina