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News article20 December 20211 min read

A toolkit to establish nutrient thresholds for water ecosystems

Toxic blue-green algal blooms are one of the major environmental problems caused by elevated nutrient levels.
© ©mivod -

Eutrophication is a plague for aquatic ecosystems and affects human welfare through multiple effects on ecosystem services. Setting nutrient concentrations targets to manage eutrophication is essential, from both scientific and practitioner perspectives.

In a recently published paper, JRC scientists and partners present a toolkit for establishing ecologically relevant nutrient thresholds.

Eutrophication results from elevated concentrations of nutrients (like phosphorus and nitrogen) in the water. It is one of the main pressures affecting both freshwater and marine ecosystems.

Various concentration thresholds currently in use

An important step towards achieving environmental quality objectives would be setting realistic targets to guide catchment managers. However, recent reviews of nutrient concentration targets adopted by Member States revealed that a wide range of concentrations are currently used.

This variation reflects the substantial differences in background concentrations and in water bodies' sensitivity to nutrient enrichment that exist within and between Member States. But it is also possible that some nutrient standards are not fit to guarantee good ecological status, both in the water body itself and in water bodies further downstream.

Reducing nutrient concentrations is key to meeting environmental quality targets

Recent predictions suggest that the Marine Strategy Framework Directive (MSFD) objectives may not be achieved even after proposed nutrient reduction measures are put in place. More ambitious steps may be required that will have implications for various industrial and agricultural sectors. So they would need to be based on a firm understanding of what concentrations are necessary to achieve Water Framework Directive (WFD) and MSFD nutrient targets.

A toolkit with guidance on its use

The new toolkit proposes a series of statistical approaches for Member States to identify and set nutrient concentrations that will support good ecological status. These approaches have been tested for lakes, rivers and coastal and transitional waters. A brief guide on how to choose the most suitable approach and how to interpret the results accompanies the toolkit. This should facilitate the establishment of comparable and consistent nutrient thresholds across all Member States.

Further information

Related Content

Establishing ecologically-relevant nutrient thresholds: A tool-kit with guidance on its use


Publication date
20 December 2021