2) Supporting information

The indicator ‘Pesticides in rivers, lakes and groundwater in Europe’ shows:

  • the percentage of reported monitoring sites with pesticides exceeding thresholds in surface waters and groundwater in Europe weighted by country area;
  • the percentage of reported monitoring sites with pesticides exceeding thresholds in surface waters, different sized rivers, lakes and groundwater in European countries, 2013-2020.

A detailed description of the methodology used to develop the pesticides indicator is provided in the accompanying ETC/ICM methods paper. 

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Justification for indicator selection

Pesticides are a topic of considerable public and policy interest across the environment, agriculture and human health domains. An overview of pesticides in the aquatic environment across Europe, as well as a standardised methodology in the form of an indicator to assess pesticide contamination levels in aquatic ecosystems has been  available since 2021. 

The indicator may not be comparable with nationally developed assessments of pesticides in water because the methodologies for calculating exceedances may differ. 

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Policy context and targets

The Water Framework Directive (WFD) and its daughter directives on environmental quality standards in water policy, as amended in 2013, and quality standards for groundwater set quality objectives and targets for pesticides in surface waters and groundwater and should protect water quality from pesticide pollution.

According to the WFD, pesticide concentrations above critical threshold levels lead to surface waters failing to achieve ‘good chemical status’, based on pesticides listed as priority substances, and ‘good ecological status’, based on pesticides listed as river basin-specific pollutants. The WFD also lists pesticides that are groundwater pollutants to assess the chemical status of groundwaters. For each pesticide, a quality standard of 0.1 µg/L was set in the Groundwater Directive, which is not a health-based, but a general precautionary limit value.

Failure to achieve effect thresholds and quality standards in water means failure to achieve the environmental objectives of the WFD.

The European Green Deal and its associated strategies and actions — the farm to fork strategy, biodiversity strategy, chemicals strategy for sustainability and zero pollution action plan — brings renewed ambition to significantly reduce the use of and risk from pesticides and improve the risk assessment of chemicals.

EU policies aimed at reducing the potential risk from pesticides are also supported by the Plant Protection Products Regulation, the Sustainable Use of Pesticides Directive and the Biocidal Products Regulation.

  • The Plant Protection Products Regulation sets out rules for the authorisation of plant protection products and their marketing, use and control. Based on this regulation, the Seventh Environment Action Programmeset the objective that, by 2020, the use of plant protection products should not have any harmful effects on human health, or unacceptable influence on the environment, and that such products should be used sustainably. 
  • The Sustainable Use of Pesticides Directive aims to reduce the risks and impacts of pesticide use on human health and the environment and to promote the use of integrated pest management and alternatives such as non-chemical approaches.
  • The Biocidal Products Regulation focuses on the marketing and use of biocidal products. 

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Legislation concerning pesticides in environmental waters is primarily set by the WFD (2000/60/EC). For surface waters, environmental quality standards (EQSs) are set in the EQS Directive (2008/105/EC), as updated by the Priority Substances Directive (2013/39/EU). EQSs are based on substances’ toxicity to or via the aquatic environment. There are 45 priority substances (or groups of substances); these include a limited number of pesticides. Member States can also identify ‘river basin specific pollutants’ for which they set the EQS. For groundwater, the Groundwater Directive (2006/118/EC), as updated by Directive 2014/80/EU, sets a common quality standard of 0.1 ug/L for any individual pesticide.

Within the European Green Deal, the EU set targets for reducing the use of and risk from chemical pesticides by 50% by 2030 in the zero pollution action plan, the farm to fork strategy and the biodiversity strategy, with a focus on improving and protecting ecosystems and biodiversity.

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Methodology uncertainty

For surface waters, effects thresholds could be identified for only 48% of the pesticides reported; 52% of all pesticides reported could not be considered in the assessment.

The calculation method used to determine exceedance rates with country weightings reduces any imbalance in the data reported with respect to the numbers of monitoring sites and pesticides reported. This reduces the impact of high levels of reporting by a few countries on the overall percentage of monitoring sites with exceedances.

This country weighting means that unusually high or low exceedance rates within a country may affect the overall indicator. This can also occur if data for only a few monitoring sites are reported but a relatively high or low proportion of these are exceedances. A minimum number of monitoring sites reported per country and year would be needed to reduce this imbalance.

There is a lack of a consistent time series of comparable data. Instead, the data for many monitoring sites were not reported for more than a few years, which disperses the spatial and temporal coverage of the data set. 

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Data set uncertainty

Monitoring data are not evenly spread across Europe, and there is considerable variation between countries in the number of monitoring sites reported and in the number of substances measured. The results are dominated by countries with the highest numbers of monitoring sites and substances reported, which is addressed using a weighting factor. However, a minimum number of monitoring sites and substances should be reported to achieve a representative overview of pesticide concentration in European waters. 

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Rationale uncertainty

In surface waters, ecotoxicologically-based effect thresholds were determined to assess exceedance rates at monitoring sites. Those thresholds indicate potential pollution by pesticides affecting communities in aquatic ecosystems. Using the lowest ecotoxicologically-based effect threshold is the most conservative criterion. The EQS have not necessarily been defined in each country with the same criteria as used here, which makes comparisons with this indicator difficult. 

In groundwater, exceedances were assessed against the 0.1ug/L quality standard set out in the Groundwater Directive. No regulated quality standards for non-relevant metabolites are available and so they were excluded from the assessment. 

The indicator demonstrates a need to harmonise limit values (including nationally set river basin-specific pollutant EQS values).  

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Temporal coverage: 2013 - 2020

Geographical coverage

  • Austria
  • Belgium
  • Bulgaria
  • Croatia
  • Cyprus
  • Czechia
  • Denmark
  • Estonia
  • Finland
  • France
  • Germany
  • Greece
  • Hungary
  • Iceland
  • Ireland
  • Italy
  • Latvia
  • Lithuania
  • Luxembourg
  • Netherlands
  • Norway
  • Poland
  • Portugal
  • Romania
  • Serbia
  • Slovakia
  • Slovenia
  • Spain
  • Sweden
  • Switzerland 

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Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)


Unit of measure

The indicator is expressed as percentages of monitoring sites where one or more pesticides exceed the effect threshold for surface waters or the quality standard for groundwater. To reduce the impact of uneven spatial and temporal data reporting, we used a country area weighting factor:

∑ Share of monitoring sites with exceedances per country (%) × country area (km²) /

∑ Area of countries with reported monitoring sites per year (km²)

The country weighting factor was not used for Figure 2 in the indicator.


Frequency of dissemination: Once a year



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