QUALITY OF WATER RETAINED IN THE NATURAL MOUNTAIN CATCHMENT (DAM RESERVOIR WAPIENICA)

The study involved assessment of the quality of water in dam reservoir Wapienica. Samples were taken from September 2011 until June 2012. The reservoir is used for providing potable water to the city of Bielsko-Biala. The catchment of the reservoir is a natural mountain catchment, without internal sources of pollution. Environmental and organizational conditions determine the good quality of water in the reservoir. Water contains little amounts of suspended matter and solutes, favorable aerobic conditions and low fertility. Also, no contamination with organic substances was reported. Water retained in the reservoir has quality category A1, thus its treatment can only consist in filtration and disinfection. Analyses showed occurrence of some heavy metals (Zn, Pb and Co) in amounts exceeding levels typical of uncontaminated natural water. Increased levels of zinc and lead might result from atmospheric deposition of contaminants, whereas occurrence of cobalt might be natural. The studies show that unmanaged mountainous regions of southern Poland may be contaminated with trace elements.