Pesticide residues in EU soils (Signal)

Pesticides protect crops by controlling pests, thus enabling stable crop production and contributing to food security. On the other hand, at high concentrations, they can be toxic to non-target species, which affects soil communities and their associated ecosystem services (for example, through reduced mineralisation and nitrification).

Soils, through its filtering and storage capacity, are a sink for contaminants, a function which is of particular importance for soils under agricultural and urban soil uses. Substances applied to plant parts above ground reach soils through spray and plant residues.

Monitoring studies of soils in Europe have confirmed that pesticides occur widely. The pesticide module of the Land use/cover area frame statistical survey (LUCAS Soil Pesticides) is the first continental-scale monitoring of pesticide residues in European agricultural soils (Vieira et al., 2023).

Results from the 2018 survey show at least one pesticide residue above the quantification limit (LOQ). Pesticide residues were found in 74.5% of the 3,473 sites investigated; most samples (57.1%) had at least two different pesticide residues, 29.8% had more than five and 11.1% had more than 10 (Vieira et al., 2023).

Large studies like this are important because it is difficult to predict pesticide occurrences from local studies or for specific management types (e.g. organic versus conventional) (Knuth et al., 2024). However, regional studies are still important since they focus on specifically selected sites, helping clarify the causes of pesticide occurrences.

A high incidence of pesticide residues is also found in organically-managed fields and non-managed areas such as forests and permanent grasslands (Hvězdová et al. 2018; Froger et al., 2023). Froger et al.(2023) detected pesticides in 98% of 47 studied soils across France (up to 33 different substances simultaneously, and a cocktail effect of molecules affecting soil biodiversity (Hvězdová et al., 2018; Kosubova et al., 2020; Geissen et al., 2021)). A moderate to high risk for earthworms in arable soils was mostly attributed to insecticides and/or acaricides.

Geissen et al. (2021) found that soils from conventional farms contained the highest mixtures of pesticide residues, with a maximum of 16 residues per sample. Soils from organic farms had significantly fewer residues, with a maximum of five residues per sample. Another study concluded that organic soils presented 70-90% lower residue concentrations than corresponding conventional soils (indicating significantly reduced management intensity). The residues with the highest frequency of detection and the highest content in soil were herbicides: glyphosate and its transformation product, AMPA, contributed 70% of cumulative herbicide residues.

Please consult the relevant indicators and signals below for a more comprehensive overview on the topic.