Water Quality in Slovenia - Agencija RS za okolje

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30 W A T E R Q U A L I T Y I N S L O V E N I A The trophic status of lakes and reservoirs evaluated on the basis of OECD criteria (Organisation for Economic Co-operation and Development) (33) is presented in Table 6. The same criteria were used in the evaluation of the status of river in the blooming period, and the presented values are the average measured values at individual depths. The exception is the Moste reservoir where sampling was carried out four times a year. Table 6: OECD criteria for the evaluation of the trophic status (33) and the evaluation of lakes/reservoirs in the years 2003 to 2006 Trophic level Total phosphorus (average) OECD CRITERIA Nitrogen inorganic (average) Transparency (average) Transparency (minimum) Chlorophyll-a (average) Chlorophyll-a (maksimum) STATUS of the lake (µg P/L) (µg N/L) (m) (m) (µg/L) (µg/L) Ultraoligotrophic < 4 < 200 > 12 > 6 < 1 < 2.5 Oligotrophic < 10 200 - 400 > 6 > 3 < 2.5 < 8 Mesotrophic 10 - 35 300 - 650 6 - 3 3 - 1.5 2.5 - 8 8 - 25 Eutrophic 35 - 100 500 - 1500 3 - 1.5 1.5 - 0.7 8 - 25 25 -75 Hypereutrophic > 100 > 1500 < 1.5 < 0.7 > 25 > 75 Lake and period of status evaluation Total phosporous Nitrogen inorganic Transparency Transparency Chlorophyll-a Chlorophyll-a (µg P/L) (µg N/L) (m) (m) (µg/L) (µg/L) NATURAL LAKES Lake Bled 1979 - 1981 72 650 1.9 1.2 17 > 75 Lake Bled 2003 - 2006 13 287 6.7 3.6 5.0 18.2 Lake Bohinj 2003 - 2006 4 456 9.5 6.2 1.1 3.4 ARTIFICIAL LAKE Velenje Lake 2006 120 1500 7.4 6.5 1.4 7.6 RESERVOIRS Šmartinsko Lake 2003 - 2006 63 758 1.2 0.8 17.3 46.4 Slivniško Lake 2004 - 2005 140 1340 1.1 1.0 21.9 62.9 Perniško Lake 2004 - 2006 133 1707 0.3 0.2 98.2 206.1 Ledavsko Lake 2003 - 2006 136 2194 0.6 0.4 70.2 176.2 Gajševsko Lake 2006 101 1329 0.8 0.5 37.6 61.8 Klivnik 2003-2005 12 870 3.3 2.6 3.7 6.5 Molja 2003-2005 17 595 2.2 1.6 7.5 17.9 Vogršček 2006 8 890 3.2 2.7 4.4 12.3 RIVER ACCUMULATION Moste 2006 32 802 5.4 2.6 2.0 3.7 Mavčiče 2003 * 152 827 - 0.2 238.7 1306.1 Vrhovo 2003 * 239 1258 - 0.7 71.0 180 Ptujsko j. 2003 * 183 1182 - 1 4.8 6.6 * Results of one sampling during the blooming period
Lake Bled S U R F A C E W A T E R S The establishment of monitoring at Lake Bled and its inflows was related to remedial action for the improvement of the lake status that was in the ‘70s already eutrophic, occasionally even hypereutrophic. The status of Lake Bled has therefore been regularly monitored since 1975. The results of monitoring show that the artificial inflow the Radovna (1964), the siphon that functions as a depth outflow from the lake (1980/81) and the partial restoration of the sewage system in Bled (1982–1985) contributed to the improvement of the status of Lake Bled. Since 1983, Lake Bled has been classified as a mesotrophic lake according to OECD criteria. A reduction of the nutrients concentration and a general improvement of the Lake Bled status are apparent in the years 2003 to 2006 in comparison with the years 1979 to 1981. But nevertheless, an occasionally increased production of phytoplankton, expressed by a relatively high average concentration of chlorophyll-a, represents a warning about pressures from the lake basin’s which cannot be entirely amended by the beneficial effects of restoration measures, the Radovna and by the siphon. In addition, the results of the monitoring of inflows show that the concentration of phosphorus, which is the essential biogenic element, has been recently increasing in Mišca. On the basis of phosphorus, Table 7 shows the effectiveness of the siphon in removing the load from the lake and pollution load of Mišca in the years 2003 to 2006. Table 7: The annual input and output of phosphorus by Mišca and the siphon in the years 2003 to 2006 Year 2003 (kg P) 2004 (kg P) 2005 (kg P) 2006 (kg P) Siphon 308 266 217 260 Mišca 231 372 335 402 Lake Bohinj According to criteria set by the Group for Alpine Lakes (34) in the process of intercalibration of biological elements, Lake Bohinj belongs to the category of alpine lakes where the impacts of human activity on the aquatic environment are either not present or are insignificant. Additionally, according to OECD criteria, Lake Bohinj was classified as a clear oligotrophic lake with low productivity in the years 2003 to 2006, although the average concentration of nitrogen compounds exceeded the limit value for oligotrophic lakes. A high concentration of nitrogen compounds has been present in Lake Bohinj since the beginning of monitoring of the lake’s status (1993) and is not increasing, which indicates that it is the natural state. With regards to phytoplankton, some species occasionally appear that were not present in previous years and are characteristic of more productive lakes. An assessment of the ecological status of Lake Bohinj will be made when the assessment methods for other biological elements are ready and will also include other pressures and not just the eutrophication. Coccal green algae Nephrocytiun agardhianum, characteristic of more productive lakes, which also appeared in Lake Bohinj in the years 2003 to 2006. 31
Page 1: Water Quality in Slovenia
Page 4 and 5: ENVIRONMENTAL AGENCY OF THE REPUBLI
Page 7 and 8: Preface In recent years, people oft
Page 9: Contents PREFACE ..................
Page 12 and 13: 10 W A T E R Q U A L I T Y I N S L
Page 15 and 16: 2 Surface Waters 2.1 2.1.1 Quality
Page 17 and 18: Ledava, Čentiba Mura, Mota S U R F
Page 19 and 20: S U R F A C E W A T E R S Exceeded
Page 21 and 22: S U R F A C E W A T E R S In Table
Page 23 and 24: S U R F A C E W A T E R S RIVER Mon
Page 25 and 26: Map 2: Saprobic quality evaluation
Page 27 and 28: S U R F A C E W A T E R S Chart 6:
Page 29 and 30: Lake Bohinj Table 5: List of water
Page 31: S U R F A C E W A T E R S In the ye
Page 35 and 36: S U R F A C E W A T E R S Table 8:
Page 37 and 38: S U R F A C E W A T E R S species a
Page 39 and 40: ��
Page 41 and 42: S U R F A C E W A T E R S Map 5: Cl
Page 43 and 44: Soča, Čezsoča Nadiža, Robič Ba
Page 45 and 46: Map 7: Quality of bathing waters in
Page 47 and 48: S U R F A C E W A T E R S Compliant
Page 49 and 50: S U R F A C E W A T E R S Table 12:
Page 51 and 52: 2.4.4 Quality of Shellfish Waters S
Page 53: Strunjan S U R F A C E W A T E R S
Page 58 and 59: 56 3.2 W A T E R Q U A L I T Y I N
Page 64 and 65: 62 3.3 W A T E R Q U A L I T Y I N
Page 67 and 68: 4 Guidelines for Future Work - Wate
Page 69 and 70: 5 References 1. Directive 2000/60/E
Page 71 and 72: R E F E R E N C E S 55. Pravilnik o
Page 73 and 74: G L O S S A R Y O F T E R M S Hydro

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