Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

111As for the sampling time (Fig. 5) the highestaverage concentrations of chlorides for the wholemonitored period were recorded in principle duringautumn and winter season with the maximum valuein September (46,8 mg.l –1 ). The increase of theirconcentration in September was probably causedby chlorides in applied potash fertilizers (KCl) onagricultural lands situating near the Nature Reserve.Cey et al. (1999) state that Cl – concentrationin waters is influenced by agricultural activitieswhich are probably the reason of raised concentrationsof chlorides in summer and autumn months.Chlorides are poorly adsorbed by soild phase of thesoil. They are washed out from the soil and theyare chemically and biochemically stabled in thewater environment. They can get into the environmentas contaminants or as products of wide scaleof human activities (sewerage, effluent waters oforganic origin, the use of potash fertilizers in agriculture(KCl), road salting during winter season)(Pitter, 1999). The minimum average concentrationof Cl – for the whole monitored period in dependenceon sampling time was in March (26,8 mg.l –1 ).60,0050,00The influence of sampling sites on the concentrationsof chlorides in the monitored years (Fig. 6)was not so strong. The highest mean concentrationwas in sampling site No. 1 in 2003 (44,4 mg.l –1 ).In 2004 the lowest mean concentration was alsorecorded in this sampling site (28,9 mg.l –1 ) (Fig.P29). The maximum average value for the wholemonitored period was in sampling site No. 3 (38,9mg.l –1 ). The minimum value of the whole periodwas recorded in sampling site No. 1 (35,2 mg.l –1 ).Based on calculated characteristic valuesof chlorides and according to the standard STN75 7221 the water in sampling site No. 4 wasranked into the 1 st class of the water surface quality(very clean water) and in sampling sites No. 1, 2, 3and 5 into the 2 nd class of the water surface quality(clean water).mg.dm -350,0045,0040,0035,0030,0025,0020,0015,0010,005,000,001 2 3 4 5mg.dm -340,0030,0020,0010,000,001 2 3 4 5 6 7 8 9 10 11 12Year 2003 Year 2004 Year 2005 Average 2003-2005Fig. 6 The average concentrations of chloridesin dependence on sampling siteYear 2003 Year 2004Year 2005 Average 2003-2005Fig. 5 The average concentrations of Cl – in dependenceon sampling timeAcknowledgementThis research was conducted thanks to thegrant project VEGA 1/0196/03 a 1/2444/05.Table 1: Calculated characteristic values and the water surface qualitySampling site 1. 2. 3. 4. 5.2–Indicator SO 4Cl – 2–SO 4Cl – 2–SO 4Cl – 2–SO 4Cl – 2–SO 4Cl –Unit mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1 mg.l –1CalculatedcharacteristicvalueClass ofquality86,4 51,5 85,7 53,2 86,4 53,2 79,8 49,7 75,5 51,0II. II. II. II. II. II. I. I. I. II.