Water Quality in Slovenia - Agencija RS za okolje

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3.2
W A T E R Q U A L I T Y I N S L O V E N I A
Groundwater Quality
Groundwater quality is influenced by the activities on the Earth’s surface and by the vulnerability
of aquifers. In flatland river valleys with predominant alluvial aquifers the conditions are ideal
for intensive agricultural production, in addition industrial and various craftsmen’s activities are
also well developed. Settlements and traffic infrastructure are denser in these valleys compared
to forested and mountainous regions of Slovenia. All the above-mentioned activities, together
with a very high vulnerability, represent a high risk of groundwater pollution. In these aquifers the
monitoring results evidence that the groundwater is polluted by nitrates and pesticides originating
mostly from the agricultural activity. Groundwater in some aquifers additionally contains chlorinated
organic solvents and heavy metals in concentrations above the quality standards. In aquifers with
karst na fissure porosity, the pressures are less intense compared to alluvial aquifers. Large parts of
the surface above these aquifers are covered by forest, which provides natural protection for the
groundwater. At the same time the land use is less intensive, so groundwater pollution is lower in
these aquifers.
The transport of pollution into the groundwater and its spreading around the aquifer depends
on several factors, like the chemical and physical characteristics of the pollutant, the precipitation
amount, the land use, the type of ground layers and the aquifer’s characteristics. Due to complex
processes influencing the level of groundwater pollution, statistical methods and modelling are
included in the interpretation of the monitoring results.
National groundwater quality monitoring, which has been carried out since 1987 (66), is the
systematic monitoring of various physical and chemical parameters in groundwater bodies.
Every year, the Environmental Agency of the Republic of Slovenia prepares in compliance with
Slovene legislative acts for groundwater (67, 68, 69) the national groundwater quality monitoring
programme (70), and carries out all monitoring phases. In accordance with the programme,
authorised laboratories analyse about 150 different parameters in groundwater sampled at all the
monitoring sites twice to four times a year.
A representative monitoring network is the basis for a reliable chemical status assessment. National
monitoring network consists of monitoring sites where groundwater is sampled. The monitoring
sites in alluvial aquifers are wells and boreholes, while in aquifers with karst and fissure porosity,
the monitoring sites are springs and wells. In 2006, the national monitoring network included 129
monitoring sites, which were more concentrated in alluvial aquifers. A significant part of these wells
and springs is intended for the drinking water supply.
Glijun spring Hubelj spring