Water Quality in Slovenia - Agencija RS za okolje

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W A T E R Q U A L I T Y I N S L O V E N I A
Table 9: The Classification of surface water intended for the abstraction of drinking water into quality classes based upon
monitoring data in the years 1998 to 2006
Surface water intended
for the abstraction of
drinking water
The first
classification
in 2002
Classification in quality classes on the basis of a five-year data set
1998–2002 1999–2003 2000–2004 2001–2005 2002–2006
Rižana A3 A2 A3 A3 A3 A3
Mrzlek A2 A2 A2 A2 A2 A2
Ljubija A2 - - - - A2
Malenščica A3 - - - - A2
Hudinja A1 - - - - A3
Bistrica A1 - - - - A2
Podroteja A2 A2 A2 A2 A2 A2
Soča A2 - - - - A3
Vipava A2 - - - - A2
Kolpa A2 - - - - A2
Veliki Obrh A1 - - - - A2
A1, A2, A3: quality classes from the best to the worse
- Five-year data set is not available
The results of the monitoring of the quality of surface water intended for the abstraction of drinking
water show that surface sources of drinking water reach the quality of A1 class according to most
physical and chemical parameters. Occasionally exceeded microbiological parameters were the reason
for the classification of the surface sources Mrzlek, Podroteja, Ljubija, Bistrica, Kolpa, Vipava, Veliki
Obrh and Malenščica into class A2. The Rižana has been classified into class A3 due to the occasional
presence of Salmonella in water. Salmonella was also identified in one out of seven samples from the
Soča, which consequently also caused the classification of the Soča into class A3. In the June 2006
sample from the Hudinja, the limit values of class A2 regarding total coliforms and faecal coliforms
were exceeded, which classified the Hudinja into class A3. Regarding the first classification in 2002,
the quality of the surface sources Rižana, Mrzlek, Podroteja, Ljubija, Kolpa and Vipava remained the
same; the quality deteriorated in the soureces Hudinja (from A1 to A3), Bistrica (from A1 to A2), Soča
(from A2 to A3) and Veliki Obrh (from A1 to A2), and it improved in the Malenščica (from A3 to A2). It
has to be noted that the Hudinja is not a constant source of drinking water, because of its turbidity
in the event of rainfall and is therefore used only in the dry season. The Veliki Obrh is also an auxiliary
source of drinking water, as the majority of water is supplied from the well in Kozarišče while the
Kolpa as a water source is gradually being phased out and a linkage of the water supply network
to the Dobličica source is planned. Public Drinking Water Supply Contractors carry out an internal
monitoring of the quality of the source of drinking water and are aware of microbiological pollutions.
In the Ljubija and Bistrica, the use of ultrafiltration is therefore planned, to remove the suspended
substances and particles of more than 0.01 μm in size and microorganisms, including bacteria and
viruses from the water.
Rižana spring Ljubija spring