Water Quality in Slovenia - Agencija RS za okolje

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3.3
W A T E R Q U A L I T Y I N S L O V E N I A
Table 18: Monitoring sites with the most polluted groundwater
Groundwater
body
Savinjska
kotlina
Krška kotlina
Dravska
kotlina
Murska
kotlina
Monitoring site Parameter Concentration (AM) AM/QS
LEVEC VC-1772 nitrates 58.8 mg NO 3 /L 1.2
metolachlor 0.32 µg/L 3.2
terbuthylazine 0.10 µg/L 1.0
desethyl-terbuthylazine 0.15 µg/L 1.5
total pesticides 0.68 µg/L 1.4
tetrachloroethene 3.08 µg/L 1.5
CERKLJE C-01 nitrates 50.2 mg NO 3 /L 1.0
bentazone 1.05 µg/L 10.5
total pesticides 1.17 µg/L 2.3
BRUNŠVIK 1750 nitrates 109.5 mg NO 3 /L 2.2
atrazine 0.25 µg/L 2.5
desethyl-atrazine 0.17 µg/L 1.7
prometryn 0.39 µg/L 3.9
total pesticides 1.02 µg/L 2.0
ŠIKOLE 1581 nitrates 85.3 mg NO 3 /L 1.7
atrazine 0.24 µg/L 2.4
desethyl-atrazine 0.15 µg/L 1.5
bentazone 0.13 µg/L 1.3
total pesticides 0.51 µg/L 1.0
KIDRIČEVO 2571 nitrates 55.5 mg NO 3 /L 1.1
atrazine 0.88 µg/L 8.8
desethyl-atrazine 0.34 µg/L 3.4
total pesticides 1.23 µg/L 2.5
RAKIČAN 2500 nitrates 60.9 mg NO 3 /L 1.2
potassium 12.0 mg/L 1.2
atrazine 0.13 µg/L 1.3
1.2-dichloroethene 146.5 µg/L 73.3
tetrachloroethene 155.0 µg/L 77.5
trichloroethene 68.8 µg/L 34.4
LHCH 370.5 µg/L 37.1
LIPOVCI 2271 nitrates 110.3 mg NO 3 /L 2.2
LHCH: The sum of volatile halogenated aliphatic hydrocarbons
AM: Yearly arithmetic mean of parameter in the monitoring site
QS: Quality standard
Trend Evaluation
desethyl-atrazine 0.19 µg/L 1.9
The behaviour of an individual parameter over a longer period of time is represented by upward/
downward concentration trends. Long-term trends of pollutants’ concentration in a groundwater
body are determined with a linear regression analysis of at least six-year sets of representative average
values for a water body (AM ). On most occasions, pollution does not affect the entire water body,
SK
so more complete information on endangered groundwater is obtained if trends are determined
with a linear regression of the annual arithmetic mean values at individual monitoring sites (AM).
Remediation measures have to be carried out when the parameter’s upward trend reaches 75% of
the quality standard.
Due to a ban on the use of atrazine, a downward trend of this pesticide and its metabolite desethylatrazine
has been established in the majority of groundwater bodies. Chart 12 shows a downward
trend of the desethyl-atrazine concentration in the period from 1998 to 2006 in the Murska kotlina
where, in 2005, representative average values (AM ) for the water body decreased below the quality
SK
standard of 0,1 μg/L. During the same period, the concentrations of desethyl-atrazine in the Krška
kotlina water body have been increasing and almost reached the quality standard in 2006 (Chart 13)