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[VD05] Nitrates in groundwater
State

Key message
Neutral

Slovenian groundwater bodies most polluted with nitrates are those with intergranular (alluvium) aquifers, particularly in north-eastern Slovenia. Groundwater in karst and fractured aquifers is less burdened with nitrates due to geographical conditions, low population density and less agricultural land. In the period 1998–2020, the average annual levels of nitrates in water bodies in the Sava valley, Ljubljansko barje, Savinja, Drava and Mura basins show a statistically significant downward trend. In other water bodies, nitrate levels are not statistically significant.

This indicator shows:

  • Average annual values ​​of nitrate in groundwater samples in Europe and Slovenia and at the sampling points of the Slovenian national monitoring in 2020.
  • Structure of agricultural land use and groundwater quality in the analzyed year.

  • Share of agricultural area in the surface of ground water bodies in Slovenia in the analyzed year.

  • Total annual nitrogen emissions from municipal wastewater treatment plants.

Charts

Figure VD05-1: Average annual values ​​of nitrate in groundwater samples at the sampling points of the Slovenian national monitoring in 2020
Sources:

ARSO, GURS 2021 (January, 2021)

Figure VD05-2: The average value of nitrate levels in Europe and in Slovenia and Slovenian groundwater bodies with predominantly intergranular (alluvial) and karst/fractured aquifers
Sources:

Standardised Database for Water Quality Monitoring, Slovenian Environment Agency; Waterbase European Environment Agency, 2021 (January, 2021)

Show data
Slovenija - alluvial aquifers[mg/l] Slovenia - karst-fractured aquifers[mg/l] Slovenia - average[mg/l] Europa - average[mg/l]
2004 40.56 7.48 15.36 20.04
2005 40.29 7.39 15.23 19.72
2006 38.59 7.41 14.84 19.50
2007 31.75 7.33 13.15 19.27
2008 32.77 6.78 12.97 19.20
2009 32.87 6.58 12.84 19.12
2010 31.95 5.50 11.80 19.28
2011 31.20 6.60 12.50 19.28
2012 30.20 5.36 11.28 19.28
2013 32.30 5.27 11.70 19.28
2014 32.21 5.27 11.69 19.28
2015 31.05 5.78 11.80 19.28
2016 25.35 5.50 11.44 19.28
2017 31.73 5.90 12.05 19.28
2018 31.95 5.61 11.88 19.28
2019 30.11 5.78 11.57 19.28
2020 29.22 6.24 11.71 19
Figure VD05-3: Average annual nitrate levels in groundwater of the more polluted water bodies
Sources:

Standardised Database for Water Quality Monitoring, Slovenian Environment Agency, 2021 (January, 2021)

Show data
1001 Savska kotlina in Ljubljansko barje[mg/l] 1002 Savinjska kotlina[mg/l] 1003 Krška kotlina[mg/l] 3012 Dravska kotlina[mg/l] 4016 Murska kotlina[mg/l] quality standard[mg/l]
1998 23.39 50.01 21.84 45.10 47.63 50
1999 22.80 43.78 23.80 48.37 39.75 50
2000 21.64 47.21 20.39 45.44 47.34 50
2001 21.94 55.49 25.68 46.46 50
2002 20.68 43.88 32.96 39.70 34.43 50
2003 20.70 50.45 22.34 40.29 39.86 50
2004 20.90 65.03 29.44 49.45 37.98 50
2005 22.90 57.83 24.76 54.01 41.99 50
2006 22.70 45.37 26.94 53.25 44.67 50
2007 18.38 47.29 21.10 39.12 32.88 50
2008 19.57 48.65 23.16 40.28 32.20 50
2009 20.63 44.83 24.19 42.13 32.57 50
2010 19.21 42.52 24.05 42.18 31.78 50
2011 19.20 43.20 21.60 39 32.90 50
2012 18.23 46.91 23.66 35.56 26.65 50
2013 18.93 40.24 28.67 42.31 31.36 50
2014 18.80 43.98 24.52 40.00 33.73 50
2015 17.96 44.66 23.64 40.27 28.73 50
2016 16.75 42.02 24.53 38.51 30.32 50
2017 16.83 49.85 24.13 39.09 28.75 50
2018 18.78 44.41 25.71 39.66 31.19 50
2019 17.46 47.75 21.85 36.11 27.37 50
2020 16.06 46.08 19.91 35.30 28.74 50
Figure VD05-4: The declining trend of the nitrate concentration in water bodies Sava, Savinja, Mura, and Drava basin in the period 1998-2020
Sources:

Standardised Database for Water Quality Monitoring, Slovenian Environment Agency, 2021 (January, 2021)

Figure VD05-5: Structure of agricultural land use and groundwater quality by water bodies in 2020
Sources:

Environmental Agency of the Republic of Slovenia, 2020. Agricultural Institute of Slovenia (2020)

Figure VD05-6: Share of agricultural area in the surface of ground water bodies in Slovenia in 2020 (%)
Sources:

Ministry of Agriculture, Forestry and Food (2020)

Note:

  Red coloured bars denote ground water bodies with poor chemical state because the nitrate concentration limit is exceeded.

Show data
Julijske Alpe v porečju Save [%] Karavanke [%] Julijske Alpe v porečju Soče [%] Kamniško-Savinjske Alpe [%] Kraška Ljubljanica [%] Goriška [%] Vzhodne Alpe [%] Cerkljansko, Škofjeloško in Polhograjsko hribovje [%] Dolenjski kras [%] Obala in Kras z Brkini [%] Posavsko hribovje do osrednje Sotle [%] Spodnji del Savinje do Sotle [%] Haloze in Dravinjske gorice [%] Goričko [%] Savska kotlina in Ljubljansko Barje [%] Vzhodne Slovenske gorice [%] Dravska kotlina [%] Zahodne Slovenske gorice [%] Murska kotlina [%] Savinjska kotlina [%] Krška kotlina [%]
2020 10.38 11.29 15.50 17.74 24.78 25.43 25.88 26.00 27.91 31.57 35.23 38.41 48.12 52.05 52.29 58.94 59.89 63.28 68.68 68.82 69.27
Figure VD05-7: Total nitrogen emissions from municipal wastewater treatment plants (t/year)
Sources:

Waste Water Treatment Plants Database, Environmental Agency of the Republic of Slovenia (2020)

Show data
Indirect outflow into groundwater [t/year] Outflow into surface waters [t/year]
2010 5.90 1993.30
2011 6.60 2011.40
2012 3.40 1710.40
2013 2.40 1707.10
2014 4.50 1634
2015 5.90 1502
2016 9.70 1321.40
2017 9.90 1315.50
2018 12 1388.60
2019 12.80 1283.10

Goals

  • To improve the state of the water environment,
  • to reduce emissions from dispersed sources (intensive agriculture, dispersed settlement without wastewater treatment),
  • to achieve a favourable state of groundwater,
  • to reduce concentrations of nitrates in overburdened groundwater below 50 mg NO3/l and to reverse the trends of increasing nitrate concentrations.

 

Methodology

Date of data source summarization
Last modified
13.05.2021
Author(s)

Polona Mihorko, Marina Gacin, Marjan Zajc, Slovenian Environment Agency; Janez Sušin, Janez Bergant, Agricultural Institute of Slovenia