Phosphorus in lakes - Eutrophication indicators in lakes

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Topics: Water ,

Assessment made on 01 May 2004

Note: new version is available!

Mar 26, 2013 - Nutrients in transitional, coastal and marine waters (CSI 021) - Assessment published Mar 2013
Jul 05, 2011 - Nutrients in transitional, coastal and marine waters (CSI 021) - Assessment published Jul 2011
Nov 29, 2005 - Nutrients in transitional, coastal and marine waters (CSI 021) - Assessment published Nov 2005
Jul 27, 2004 - Nitrate in groundwater
Jul 27, 2004 - Frequency of low bottom oxygen concentrations in coastal and marine waters

Generic metadata

Classification

Water (Primary theme)

DPSIR: State

Identification

Indicator codes

WEU 003

Geographical coverage:

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Contents

Policy issue: Is the condition regarding eutrophication of Europe's lakes improving?

Key messages

Eutrophication of European lakes is decreasing. Phosphorus concentrations are decreasing, and the proportion of lakes and reservoirs with high phosphorus concentration has reduced since 1980.
However, there are still many lakes and reservoirs with high concentrations of phosphorus due to human influence.

Figures

Change in average summer or annual concentration of phosphorus (µg P/l). Based on all lakes with data for all four periods, 386 in total

Key assessment

During the past few decades there has been a gradual reduction in phosphorus concentrations in many European lakes. Discharges of urban wastewater have been a major source of pollution by phosphorus, but as purification has improved and many outlets have been diverted away from lakes, this source of pollution is gradually becoming less important. Agricultural sources, both from animal manure and from diffuse pollution by erosion and leaching are similarly important and need attention to obtain good water quality in the lakes. The improvements have generally been relatively slow despite the pollution abatement measures taken. This is at least partly because of the slow recovery due to internal loading and because the ecosystems can be resistant to improvement and thereby maintain a bad steady state. Particularly in shallow lakes, such problems may call for restoration measures.