European policy on eutrophication: introduction

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One of the major pollution problems facing European waters is eutrophication. European policy has consistently identified eutrophication as a priority issue for water management. Substantial progress has been made in combating eutrophication but there remains several areas where co-ordination is necessary to achieve a harmonised result for different policy areas. Thus an activity was initiated under the Common Implementation Strategy of the Water Framework Directive and the European Marine Strategy to provide guidance on:

  • the harmonisation of assessment methodologies and criteria for the trophic status assessment in rivers, lakes, transitional, coastal and marine waters
  • the co-ordination of monitoring and reporting
  • the harmonisation of models for assessing or predicting anthropogenic or natural nutrient loading into inland and marine waters based on nutrient sources information or nutrient sources scenarios
  • the systematic identification of sources
  • harmonisation of dose-respons models linking nutrient loading to ecological impact in different water body types and categories

Overview of policy instruments

A number of EC Directives require member states to monitor parameters relevant to eutrophication, however only the Urban Wastewater Treatment (UWWT) Directive and the Nitrates Directive have an explicit requirement to assess eutrophication. The Water Framework Directive (WFD) supports both these Directives in its provisions for protected areas, and has an implicit requirement to assess eutrophication when classifying the ecological status of surface water bodies. Unlike the UWWT Directive and the Nitrates Directive, the WFD stipulates a specific framework for assessing water quality. Eutrophication assessment criteria and methods have also been developed by several European conventions, including OSPAR and HELCOM.

In order to identify water bodies that are eutrophic (or may become eutrophic in the near future if protective action is not taken) every 4 years the existing sensitive areas have to be reviewed and new ones have to be designated.

Waters should be monitored for nitrates, in order to identify waters affected by pollution and waters, which could be affected by pollution if action is not taken, and to designate their catchment area as nitrate vulnerable zone. This monitoring program should be repeated at least every four years. A review of the eutrophic state of surface waters, estuaries and coastal waters should be made every four years.

The requirements to assess eutrophication are included in the classification of Ecological Quality Status where nutrient enrichment affects biological and physico-chemical quality elements. The WDF requires the assessment of physicochemical quality elements (every 3 months), phytoplankton (every 6 months), aquatic flora (every 3 years), macroinvertebrates (every 3 years) and fish (every 3 years).

The Marine Strategy Framework Directive (MSFD) requirements to assess eutrophication in marine and coastal waters are based on 'good' environmental status concept. Hence the MSFD does not require additional monitoring in coastal waters as regards assessment of eutrophication, as these waters were already covered by the WFD. The MSFD does require a marine monitoring program to be established by 2014.

The Ospar eutrophication strategy explicitly lists requirements for assessing the eutrophication status in OSPAR maritime waters. Ospar requires the monitoring of selected parameters for nutrient enrichment, direct effects, indirect effects and other possible effects.

The convention explicitly states that in the Baltic Sea nutrient inputs, emissions, discharges and losses as well as nutrient concentrations and their effects need to be assessed and quantified.


WFD CIS Guidance Document No. 23. Guidance Document on Eutrophication assessment in the context of European water Policies

The main author of this article is Daphnis De Pooter
Please note that others may also have edited the contents of this article.

Citation: Daphnis De Pooter (2020): European policy on eutrophication: introduction. Available from [accessed on 18-07-2024]