Pesticides were assessed against effect or quality thresholds between 2013 and 2022. One or more pesticides were detected above their effect threshold at 9% to 25% of all surface water monitoring sites. Exceedances were often caused by imidacloprid, cypermethrin and metolachlor. Exceedances of one or more pesticides were detected at between 4% and 13% of groundwater monitoring sites, mainly by atrazine and its metabolites, glyphosate and bentazone. Differences in weather, crop type and reporting mean that changes between years may not be significant.

Figure 1. Percentage of reported monitoring sites with pesticides exceeding thresholds in a) surface waters and b) groundwater in Europe weighted by country area

Percentage of reported monitoring sites with pesticides exceeding thresholds in a) surface waters and b) groundwater in Europe weighted by country area

Pesticides can contaminate surface waters and groundwater and if their concentrations are above critical thresholds, they can be harmful to the environment. The European Green Deal sets targets to reduce the use of and risks from chemical pesticides by 50% by 2030 in the Zero Pollution Action Plan, Farm to Fork and Biodiversity strategies, with a focus on protecting ecosystems and improving biodiversity.

The Water Framework Directive (WFD) sets environmental quality standards for pesticides in surface water. To assess the chemical status of groundwater, a precautionary quality standard of 0.1µg/L is set for pesticides according to the Groundwater Directive, reflecting the desire to keep pesticide concentrations in groundwater at low levels.

In 9% to 25% of all surface water monitoring sites, one or more pesticides were detected above the effect threshold each year between 2013 and 2022 (Figure 1). Exceedances of one or more pesticides were detected at between 4% and 13% of groundwater monitoring sites.

Pesticides most often causing exceedance in surface water monitoring sites (in absolute numbers) in the last six years are the insecticides imidacloprid and cypermethrin and herbicide metolachlor. These were approved for use as plant protection products for at least part of the monitoring period. The proportion of monitoring sites with exceedances has decreased from 2020 to 2022 (Figure 1). Reporting from large countries with few monitoring sites and fewer exceedances may explain part of the decrease, due to weighting by country surface area.

In groundwater, the herbicide atrazine and its metabolites as well as glyphosate and bentazone caused most exceedances in the last six years, as a proportion of total monitoring sites. Atrazine was not approved for use in plant protection products during the monitoring period. Despite restrictions on atrazine since 2007, it continues to be found in groundwater, as it is very persistent. Glyphosate is currently approved until December 2033. Bentazone is currently approved until May 2025 and renewal is under review.

Losses from the application of pesticides may vary considerably between years, depending upon, for example, crop type and the weather, while the frequency of monitoring of pesticides in surface waters can be limited to one year out of three. Characteristics of the monitoring campaigns (e.g. number of samples taken annually, number of pesticides monitored, number of monitoring sites) may vary from year to year. Changes to the approval status of pesticides influence their use and presence in water, which can also lead to difficulties in interpreting trends over time. For these reasons, changes between years may not be significant.

Figure 2. Percentage of reported monitoring sites with pesticides exceeding thresholds in surface waters, rivers, lakes and groundwater in European countries, 2017-2022

Figure 2 focuses on the more recent, shorter period between 2017 and 2022, where pesticides were reported from a total of 10,942 monitoring sites for surface waters and 15,128 sites for groundwater. The number of sites with data reported for surface waters varies by country from less than 10 (Hungary, Iceland, Luxembourg, Malta, Switzerland) to more than 1,000 sites (France, Italy, Spain). There is similar variation in groundwater monitoring sites. Numbers range from 33 in Lithuania to more than 4,000 sites in Italy, with over 1,000 in Austria, France, Germany, Spain.

The number of pesticides reported in surface waters ranges from fewer than ten substances (Iceland, Malta, Romania, Switzerland) to more than 100 substances (Belgium, Czechia, Estonia, Finland, France, Germany, Italy, Netherlands, Spain) (Figure A1). For groundwater, the lowest number of pesticides monitored was reported from Austria (6) and the highest number from France (272).

Exceedance rates of more than 30% were reported in 7 out of 31 countries for surface waters and in none of 22 countries for groundwater.