Nitrogen and phosphorus in rivers

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Topics: Water ,

Assessment made on 01 Jan 2004

Note: new version is available!

Generic metadata

Classification

Water (Primary theme)

DPSIR: State

Identification

Indicator codes

WEU 002

Geographical coverage:

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Contents

Policy issue: Is pollution with nutrients and organic matter decreasing?

Key messages

Concentrations of phosphate have decreased in the rivers of the EU and accession countries during the 1990s reflecting the general improvement in waste water treatment over this period
Nitrate concentrations in rivers have remained relatively stable throughout the 1990s and are highest in those western European countries where agriculture is most intensive

Figures

Nitrate concentrations in rivers in western and northern Europe and in accession countries Concentrations are the median of the annual average concentrations at each monitoring station

Phosphate concentrations in rivers in western and northern Europe and in accession countries Concentrations are the median of the annual average concentrations at each monitoring station

Nitrate concentrations since the 1950s in selected European rivers

Key assessment

Large inputs of nutrients arising from human activities into rivers can lead to eutrophication, adversely affecting the ecology and limiting the use of rivers for drinking water abstraction and recreation. Nutrients occur naturally but it is difficult to determine precise background concentrations for different types of river. Generally background concentrations for phosphate are approximately 10 µg/l as P and for nitrate are between 0.4 to 4 mg/l as NO₃.

In western Europe and accession countries, nutrient concentrations are above these background levels. In the case of phosphate, concentrations above background levels may be having significant impacts on the ecological status of many rivers, particularly as phosphorus is the limiting nutrient in many freshwater systems. The concentrations of phosphate have decreased in western and accession countries in the 1990s, and in northern Europe are close to background levels.

The concentrations of nitrate are highest in the rivers of western Europe where agriculture is the most intensive, and lowest in northern Europe where concentrations are within background ranges. Concentrations in the accession countries are above background levels and have remained relatively unchanged throughout the 1990s. Concentrations in western Europe have remained relatively stable throughout the 1990s.

Nitrate concentration increases are evident in four rivers for which there is a long time series available. These are the river Rhine (which has shown recent decreases in concentrations), the River Ythan and the River Tyne in Scotland and the River Seine in France.