Water Quality in Slovenia - Agencija RS za okolje

S U R F A C E W A T E R S
Compliant to the regulations, the quality of fresh water needed for the life of fish species is evaluated for each
year individually, according to the mandatory and guide values for salmonid and cyprinid waters, specified
in Table 10. Only the results of the samples collected in exceptional natural conditions are excluded. The
mandatory or guide values of salmonid and cyprinid waters are not exceeded, if the measurements of the
samples collected within the minimum frequency of a one-year period shows that:
• 95% of samples do not exceed the mandatory or guide values for the parameters pH, BOD , non-
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ionized ammonia, total ammonium, nitrite, total residual chlorine, total zinc and dissolved copper;
when the sampling frequency is lower than one sample per month, both the abovementioned
values and comments shall be respected for all the samples,
• the percentage of samples pertaining to the ‘dissolved oxygen’ parameter, as listed in Table 10, is
not lower than the mandatory or guide values,
• the average concentration defined for the ‘suspended solids’, does not exceed the mandatory or
guide values.
Salmonid or cyprinid water is of not compliant quality and is considered over polluted if the
results, according to the above-mentioned evaluation show that the mandatory values have been
exceeded.
Table 10: Mandatory and guide values for salmonid and cyprinid waters
Parameter Expressed
as
Unit
Dissolved oxygen (1) O 2 mg/L
pH
Salmonid waters Cyprinid waters
Guide value
50% ≥ 9
100% ≥ 7
Mandatory
value
50% ≥ 9
100% ≥ 6
6 - 9
∆± 0.5 (2)
Guide value
50% ≥ 8
100% ≥ 5
Mandatory
value
50% ≥ 7
100% ≥ 4
6 - 9
∆± 0.5 (2)
Suspended solids mg/L ≤ 25 ≤ 25
BOD5 O2 mg/L ≤ 3 ≤ 6
Total phosphorus PO4 mg/L ≤ 0.2 ≤ 0.4
Nitrite NO2 mg/L ≤ 0.01 ≤ 0.03
Ammonia NH3 mg/L ≤ 0.005 ≤ 0.025 ≤ 0.005 ≤ 0.025
Ammonium NH4 mg/L ≤ 0.04 ≤ 1 ≤ 0.2 ≤ 1
Total residual chlorine HOCl mg/L ≤ 0.005 ≤ 0.005
Total zinc (3) , Zn mg/L 0.3 1.0
Dissolved copper (3) , Cu mg/L 0.04 0.04
(1) The percentage represents the number of samples collected in a one-year period
(2) Artificially induced pH changes must not exceed ± 0.5
(3) The values coresponded to water hardness of 100 mg/L CaCO3
The quality of salmonid and cyprinid waters in 2006 is shown in Map 9. In salmonid water sections,
the mandatory values were not exceeded at any monitoring sites; in cyprinid water sections, a not
compliant quality of the Dragonja at Podkaštel was determined due to too low oxygen concentration
in one sample.
The assessment of the salmonid and cyprinid water sections quality in the years 2003 to 2006 is
presented in Table 11; not compliant parameters are shown in Table 12.
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