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You are here: Home / Data and maps / Indicators / Nutrients in freshwater / Nutrients in freshwater (CSI 020) - Assessment published Oct 2012

Nutrients in freshwater (CSI 020) - Assessment published Oct 2012

Topics: ,

Generic metadata

Topics:

Water Water (Primary topic)

Tags:
soer2010 | biodiversity | csi | nitrates | nutrients | freshwater quality | orthophosphate | lakes | water | rivers | thematic assessments | freshwater | phosphorus
DPSIR: State
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CSI 020
Dynamic
Temporal coverage:
1992-2010
 
Contents
 

Key policy question: Are concentrations of nutrients in our freshwaters decreasing?

Key messages

  • Average nitrate concentrations in European groundwaters increased from 1992 to 1998, but have declined again since 2004.
  • The average nitrate concentration in European rivers decreased by approximately 11% between 1992 and 2010 (from 2.5 to 2.2 mg/l N), reflecting the effect of measures to reduce agricultural inputs of nitrate as well as improvement in wastewater treatment.
  • Average orthophosphate concentrations in European rivers have decreased markedly over the last two decades, being more than halved between 1992 and 2010 (54% decrease). Also average lake phosphorus concentration decreased over the period 1992-2010 (by 31%), the major part of the decrease occurring in the beginning of the period, but is still ongoing. The decrease in phosphorus concentrations reflects both improvement in wastewater treatment and reduction in phosphorus in detergents.
  • Overall, reductions in the levels of freshwater nutrients over the last two decades primarily reflect improvements in wastewater treatment. Emissions from agriculture continue to be a significant source.

Average concentrations of nutrients in European groundwaters and surface waters (1992-2010) Fig. 1a: Nitrate in groundwater; Fig. 1b Nitrate in rivers; Fig. 1c Orthophosphate in rivers; and Fig. 1d: Total phosphorus in lakes

Note: Concentrations are expressed as annual mean concentrations. Only complete series after inter/extrapolation are included (see indicator specification). The number of groundwater bodies/river stations/lake stations included per country is given in parenthesis.

Data source:
Downloads and more info

Key assessment

Nitrate in groundwaters: There was a slight increase in annual mean nitrate concentration in European groundwaters from 1992 to 1998. Since 2004 the concentrations have declined again, but in 2010 the mean concentration was still about 1 mg/l higher than in 1992.

Nitrate in rivers: At the European level there has been an 11 % decrease in concentrations of nitrate.

Agriculture is the largest contributor of nitrogen pollution, and due to the EU Nitrate Directive and national measures the nitrogen pollution from agriculture has been reduced in some regions during the last 10-15 years, this reduced pressure is reflected in lower river nitrate concentrations.

Phosphorus in rivers. The average concentrations of orthophosphate in European rivers more than halved over the period 1992-2010. In many rivers the reduction started in the 1980s. The decrease is due to the measures introduced by national and European legislation, in particular the Urban Waste Water Treatment Directive [4], which involves the removal of nutrients. Also the change to use of phosphate-free detergents has contributed to lower phosphorus concentration.

Phosphorus in lakes. During the past few decades there has also been a gradual reduction in phosphorus concentrations in many European lakes. As treatment of urban wastewater has improved, phosphorus in detergents reduced, and many waste water outlets have been diverted away from lakes, phosphorus pollution from point sources is gradually becoming less important. However, diffuse runoff from agricultural land continues to be an important source of phosphorus in many European lakes. Moreover, phosphorus stored in the sediments can keep lake concentrations high and prevent improvement of water quality despite a reduction in inputs.

Specific policy question: Are nitrate concentrations in our groundwater decreasing?

Nitrate concentrations in groundwater between 1992 and 2010 in different geographical regions of Europe.

Note: The data series per region are calculated as the average of the annual mean for groundwater bodies (GWBs) in the region. Only complete series after inter/extrapolation are included (see indicator specification). The number of groundwater bodies included per geographical region is given in parentheses.

Data source:
Downloads and more info

Specific assessment

Present concentrations per country

See also WISE interactive maps: Nitrates in groundwater by country

Groundwater nitrate concentrations primarily reflect the relative proportion and intensity of agricultural activity. Although there were no countries where the average groundwater nitrate concentrations exceeded the threshold Groundwater Quality Standard of 50 mg/l nitrates as laid down in the Groundwater Directive (2006/118/EC) [2] in 2010, 18 out of 33 countries had groundwater bodies (GWBs) with average concentration above the standard. Belgium, Denmark and Spain had the highest proportion (>20%) of GWBs with average concentration above the standard, but there was also a high proportion (10-20%) of GWBs above the standard in Austria, Bulgaria, Cyprus, Czech Republic, Germany and the Netherlands. Groundwater nitrate concentrations were generally low (most or all GWBs < 10 mg/l NO3) in Albania, Bosnia and Herzegovina, Croatia, Finland, Iceland, Liechtenstein, Lithuania, Norway, Serbia and Sweden.

Trends in groundwater nitrate concentration (see also Fig. 1)

Looking at individual GWBs there is wide variation in trends, with 27% of the GWBs showing significantly decreasing nitrate concentrations since 1992 (an additional 4% showed a marginally significant decrease), while 23% of the GWBs showed significantly increasing concentrations (an additional 3% marginally significant). The countries with the highest proportions of GWBs with significant decreasing trends were the Netherlands, Portugal and Slovakia.

Geographical region time series and trends (Fig. 2)

There is marked variation in groundwater nitrate concentrations between different geographical regions of Europe. In Western Europe the concentrations are high, and the levels have been fairly stable over the whole period, with similar proportions of decreasing and increasing trends, and about half the GWBs with no trend. The other regions are represented by far fewer GWBs. The results show that Northern Europe is at the other end of the scale compared to Western Europe, with low concentrations. But as for Western Europe the levels have been fairly stable over time. In Eastern Europe the average concentrations are slightly lower after 1998, currently 3-4 mg/l lower than in Western Europe. The proportion of significantly decreasing trends (41%) was clearly higher than the proportion of significantly increasing trends (14%). In Southeastern Europe (only represented by Bulgaria) the pattern was opposite, with average concentrations showing a marked increase until 1998 and variable concentrations since then, currently around the same level as for Western Europe. However, the proportions of significantly increasing and decreasing trends were similar (21% and 25%, respectively). 

Specific policy question: Are concentrations of nutrients in our surface waters decreasing?

Nitrate concentrations in rivers between 1992 and 2010 in different geographical regions of Europe.

Note: The data series per region are calculated as the average of the annual mean for river monitoring stations in the region. Only complete series after inter/extrapolation are included (see indicator specification). The number of river monitoring stations included per geographical region is given in parentheses

Data source:
Downloads and more info

Nitrate concentrations in rivers between 1992 and 2010 in different sea regions of Europe.

Note: The sea region data series are calculated as the average of annual mean data from river monitoring stations in each sea region. The data thus represents rivers or river basins draining into that particular sea. Only complete series after inter/extrapolation are included (see indicator specification). The number of river monitoring stations included per sea region is given in parentheses.

Data source:
Downloads and more info

Phosphorus concentrations in rivers (orthophosphate) between 1992 and 2010 in different geographical regions of Europe.

Note: The data series per region are calculated as the average of the annual mean for river monitoring stations in the region. Only complete series after inter/extrapolation are included (see indicator specification). The number of river monitoring stations included per geographical region is given in parentheses

Data source:
Downloads and more info

Phosphorus concentrations in rivers (orthophosphate) between 1992 and 2010 in different sea regions of Europe

Note: The sea region data series are calculated as the average of annual mean data from river monitoring stations in each sea region. The data thus represents rivers or river basins draining into that particular sea. Only complete series after inter/extrapolation are included (see indicator specification). The number of river monitoring stations per sea region is given in parentheses.

Data source:
Downloads and more info

Phosphorus concentrations in lakes (total phosphorus) between 1992 and 2010 in different geographical regions of Europe.

Note: The data series per region are calculated as the average of the annual mean for river monitoring stations in the region. Only complete series after inter/extrapolation are included (see indicator specification). There were no stations with complete series after inter/extrapolation in the South and Southeast regions. The number of lake monitoring stations included per geographical region is given in parentheses

Data source:
Downloads and more info

Specific assessment

Nitrate

Present concentrations per country 

See WISE interactive maps: Mean annual Nitrates in rivers 

Rivers draining land with intense agriculture or high population density generally have the highest nitrate concentrations. Rivers with nitrate concentrations exceeding 5.6 mg/l N are found predominantly in northwest France, southeast UK and Spain. However, a high proportion (>20%) of rivers with concentrations exceeding 3.6 mg/l N are found in many other countries, particularly in Belgium, Cyprus, the Czech Republic, Denmark, Germany, Luxembourg and Montenegro. Rivers in the more sparsely populated Northern Europe and mountainous regions generally have average concentrations less than 0.8 mg/l N.

Trends in nitrate concentration (see also Fig. 1)

Overall there has been a significant decrease in river nitrate concentrations at 32% of the stations (an additional 6% marginally significant), while there has been a significant increase at 14% of the stations (an additional 4% marginally significant). The countries with the highest proportions of river stations with significant decreasing trends are the Czech Republic, Denmark, Germany and Slovakia. Across Europe as a whole, the rate of improvement is still slow, reflecting the continued significance of agricultural nitrogen emissions.

Geographical region time series and trends (Fig. 3)

There is marked variation in river nitrate concentrations between regions, with Western Europe rivers having 2-3 mg/l higher concentrations than Northern Europe, on average, and the remaining regions being somewhere in between. Except for the increasing trend in Southern Europe, nitrate concentrations are generally decreasing (least pronounced in Eastern and Northern Europe).

Sea region time series and trends (Fig. 4)

Nitrate concentrations in rivers vary markedly between the sea regions of Europe. The average nitrate concentration in rivers draining to the Greater North Sea is currently around 1-2 mg/l N higher than that in rivers feeding the Baltic Sea, the Black Sea, the Celtic Seas, Bay of Biscay and the Iberian Coast and the Mediterranean Sea and around 3.5 mg/l N higher than that of rivers draining to the Arctic Ocean. The difference compared to the other sea regions was even larger at the beginning of the time series.

The Greater North Sea is the only sea region where there is a marked decreasing trend. However, both for the Arctic Ocean, the Baltic Sea and the Black Sea regions there are markedly more significant decreasing than increasing trends. For the Mediterranean Sea there is virtually no trend, with about equally many increasing and decreasing trends, and a majority of the stations (61%) having no significant trend. In the Celtic Sea, Bay of Biscay and the Iberian Coast region there are markedly more increasing than decreasing trends.

Phosphorus

Present concentration per country

See also WISE interactive maps: Mean annual Orthophosphate in rivers & Mean annual Total Phosphorous in lakes

Relatively low concentrations of phosphorus in rivers and lakes are found in Northern Europe (Norway, Sweden, and Finland), the Alps and the Pyrenees, predominantly reflecting regions of low population density and/or high levels of wastewater collection and treatment. In contrast, relatively high concentrations (greater than 0.1 mg/l P) are found in several regions with high population densities and intensive agriculture, including: Western Europe (southeast UK, the Netherlands, Belgium, western Germany, France), Southern Europe (southern Italy, central Spain and mid-Portugal), Eastern Europe (Hungary, Slovakia, Czech Republic, Poland), and South-Eastern Europe (Bulgaria, Former Yugoslav Republic of Macedonia, Serbia, Kosovo under UNSC Resolution 1244/99, Turkey). Given that phosphorus concentrations greater than 0.1-0.2 mg/l P are generally perceived to be sufficiently high to result in freshwater eutrophication, the observed high values in some regions of Europe are of particular concern.

Trends in phosphorus concentration (see also Fig. 1)

Average concentrations of orthophosphate in European rivers have decreased markedly since 1992, particularly during the first half of this period. At 48% of the river stations there has been a significant decline in orthophosphate concentration since 1992 (an additional 6% marginally significant), while there has been a significant increase at only 6% of the stations (an additional 2% marginally significant). For lakes there has been a significant decline in total phosphorus concentrations since 1992 at 29% of the stations (an additional 5% marginally significant), while there has been a significant increase at 10% of the stations (an additional 3% marginally significant). This decrease reflects the success of legislative measures to reduce emissions of phosphorus such as those required by the Urban Waste Water Treatment Directive [4].

Sea region time series and trends (Fig. 6)

Orthophosphate concentrations are generally lowest for rivers draining to the Arctic Ocean and Baltic Sea and highest for rivers draining to the Celtic Seas, Bay of Biscay and the Iberian Coast. There is a clear decline in all regions except the Arctic Ocean, although less pronounced for rivers draining to the Baltic Sea. Although the decline is less in the latter half of the period, there is still a decline going on.

Geographical region time series and trends (Fig. 5 and Fig.7)

Northern Europe has markedly lower river orthophosphate concentrations than in the other regions of Europe. The same pattern is seen for lake total phosphorus concentrations. River orthophosphate concentrations have generally decreased in all regions except Northern Europe, where there has hardly been any change. The trend is strongest for Western Europe and least strong for Southeastern Europe.

Lake total phosphorus (Fig. 7) shows a similar strong decrease for Western Europe, but the trend may be leveling out from 2005. There is virtually no trend in lake total phosphorus in Northern and Eastern Europe.

The difference between lake and river data for Eastern Europe is partly caused by the inclusion of a number of Czech and Slovak stations in the rivers dataset, with predominantly negative trends. In addition the lake dataset includes a Latvian lake with fairly high, and increasing concentrations. Overall, the trend statistics for Eastern Europe lake total phosphorus indicates mainly decreasing trends (47% significant), but this decrease is hardly visible from the mean concentration. 

References and links to policy information

[1] The Drinking Water Directive (DWD): Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption.

[2] Groundwater Directive (2006/118/EC).

[3]  The Nitrates Directive: Directive 91/676/EEC on nitrates from agricultural sources.

[4] The Urban Waste Water Directive (UWWD): Council Directive 91/271/EEC concerning urban waste-water treatment. 

[5] The Water Framework Directive (WFD): Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the Community action in the field of water policy.

[6] EEA Core Set of Indicators CSI001 Emissions of acidifying substance and CSI005 Exposure of ecosystems to acidification, eutrophication and ozone

Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Peter Kristensen

Ownership

EEA Management Plan

2012 1.4.2 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 1 year in July-September (Q3)

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