Monitoring pesticide pollution in European rivers, lakes and groundwater

Pesticide monitoring data in European waters

The Water Framework Directive (WFD) and its daughter directives on environmental quality standards and groundwater set quality objectives to protect water from pollution. According to the WFD, concentrations above threshold levels lead to surface waters failing to achieve ‘good chemical status’, based on chemicals listed as priority substances, and ‘good ecological status’, based on chemicals listed as river basin-specific pollutants. The Groundwater Directive includes pollutants used to assess the chemical status of groundwaters. A number of pesticides are included as EU-wide priority substances, while countries can identify pesticides as river basin specific pollutants and groundwater pollutants as relevant.  

EEA countries can submit detailed monitoring data via the Water Information System for Europe – State of the Environment (WISE SoE) data flow to the EEA. Up to 38 countries have contributed data on rivers, lakes, and groundwater to the Waterbase - Water Quality ICM. This data collection includes concentrations of chemicals and nutries. Through harmonising data collection and reporting, Waterbase -Water Quality ICM can be used to support transparent assessment, highlights areas in need of improvement, and tracks the progress of water policies.

Thresholds used to assess exceedances

Effect thresholds for surface water assessment refer to concentration limits of pollutants (such as pesticides) above which harmful effects on organisms or ecosystems are likely to occur. If a measured concentration in water is above the threshold, it is considered an exceedance. To assess pesticide exceedances, effect threshold were assigned to each pesticide according to the list below:

• Surface waters: Based on ecotoxicological thresholds, prioritising:
• EU Environmental Quality Standards (EQS)
• Watch List maximum detection limits (provided in EU Commission Decisions)
• Surface water watch lists under the Environmental Quality Standards Directive
• River Basin Specific Pollutant EQS (lowest ecotoxicologically-based national value used (Annex4)
• Stockholm Convention (Persistent Organic Pollutants)

• Groundwater: Assessed against the 0.1 µg/L standard for persticides set in the Groundwater Directive.

More detailed information on the methodology is available here.

The maps shown on this page apply a similar methodology to that developed for the EEA indicator for Pesticides in rivers, lakes and groundwater in Europe. In that indicator, pesticide concentrations in surface water and groundwater water bodies are assessed against effect or quality thresholds. If one or more pesticides exceed these thresholds, it results in the corresponding water body being classified as exceeded. A detailed description is provided in "Methodology for indicator on pesticides in European waters".