Ecological risk of pesticides in EU soils (Signal)

Key messages: Chemical pesticide mixtures potentially pose a risk of adverse effects to soil organisms in 14% of the 3,473 sites monitored in the 2018 LUCAS survey. The insecticides imidacloprid and chlorpyriphos and the fungicide epoxiconazole were the main drivers of toxicity for the high-risk sites. All three were withdrawn from the list of approved active ingredients in 2020. Compared to a previous pilot study in 2015, results show no sign of progress towards risk reduction.

Distribution of risk quotients (RQs) for soil organisms across LUCAS pesticides sites in the EU-27+UK, 2018

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Although pesticides are widely used in European agriculture, data on pesticide residues in soil in the EU are sparse. The Land Use/Cover Area frame Survey (LUCAS) comprises data on pesticide concentrations in soils collected from across the EU. LUCAS pesticides started with a pilot study in 2015, followed by a first full sampling campaign in 2018 which monitored 118 substances in 3,473 mainly agricultural sites. The LUCAS soil pesticides monitoring program and this signal respond to the need for risk-based indicators for soil.

The risk of pesticides in soil is calculated based on the ratio between the pesticide concentration measured in single soil samples and an effect threshold for soil organisms. An assessment factor of five is applied to the risk quotient in line with regulatory risk assessment practices. The sum of risk quotients is an indicator of the total risks associated with the measured set of pesticides. A sum greater than one indicates that there is potential risk.

In 2018, there was a potential risk of adverse effects to soil organisms associated with pesticide mixtures in soil in 14% of monitored sites. The risk drivers were the insecticides imidacloprid and chlorpyriphos, and the fungicide epoxiconazole. These active substances were approved for use in the EU at the time of the monitoring survey but have since lost their approval status in 2020.

The risk indicator was between 0.1 and 1 for 23% of the monitored sites.

These results can be partially compared to that of the 2015 pilot study, with 73 sites common to those monitored in 2018. Although the scope is limited in the number of comparable sites, results from the two monitoring campaigns show no sign of progress towards risk reduction. Results from the next survey in 2022-2023 will help further assess the trend in ecological risks from pesticides in EU soils. It will also complement the assessment of progress towards the European Commission’s Zero pollution action plan target of a 50% reduction in the use and risk of chemical pesticides by 2030.

At the level of individual substances, these risk calculations can help verify the outcome of prospective risk assessments performed under the Regulation (EC) 1107/2009 concerning the placement of plant protection products on the market.

The risk indicator (RI_soil,NOECmin in the equation below) is calculated for each sampling site as the sum of risk quotients multiplied by an assessment factor of five. The risk quotients correspond to the ratio between the pesticide concentration (C_soil,i) measured in the samples and the lowest no observed effect concentration (NOEC_soilmin,i) of an active ingredient (or its metabolite) among experimental chronic NOEC values.

NOEC values were retrieved from the European Food Safety Authority’s (EFSA) OpenFoodTox, the United States Environmental Protection Agency (US EPA) Ecotox database, the University of Hertfordshire Pesticides Properties Database and the OECD eChemPortal.

Risk calculations are an adaptation to technical guidance on soil risk assessment. There are notable differences. The calculated risk cannot be linked to specific species or endpoints due to the diversity of studies included in the collection of experimental, chronic NOECs. Risk quotients derived using NOEC from different species end endpoints are summed in a single risk indicator. The assumption adds conservatism to the risk indicator. Regarding toxicity data, this indicator draws ecotoxicological data from four public datasets, including but not limited to data reported in EFSA’s OpenFoodTox. The three databases from which experimental data were collected implement different approaches of data quality control. Other differences relate to the EFSA’s tiered approach to calculate and refine risk estimates (which depend, for example, on the availability of toxicity data); substances’ half-lives and hydrophobicity; and soil tillage practice (which defines soil mixing depth).

Monitoring during the 2015 pilot study and the 2018 study was done with consistent sampling design and analytical methods, but limited to 73 substances. This partial comparison showed no evidence of risk reduction, as reported in Franco A. et al. (forthcoming). The next sampling campaign of 2022-2023 is ongoing and results are expected by 2024.

References and footnotes

Vieira, D., et al., 2023, Pesticides residues in European agricultural soils - Results from LUCAS 2018 soil module, Publications Office of the European Union, Luxembourg, doi:10.2760/86566, JRC133940.
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Franco, A., et al., ‘Evaluation of the ecological risk of pesticides residues investigated in the European LUCAS soil monitoring 2018 survey’, (DOI: 10.1002/ieam.4917).
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EU, 2018, Commission Implementing Regulation (EU) 2018/783 of 29 May 2018 amending Implementing Regulation (EU) No 540/2011 as regards the conditions of approval of the active substance imidacloprid (Text with EEA relevance. ) (OJ L 132, 30.5.2018, pp. 31-34).
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EU, 2019, Commission Implementing Regulation (EU) 2019/168 of 31 January 2019 amending Implementing Regulation (EU) No 540/2011 as regards the extension of the approval periods of the active substances abamectin, Bacillus subtilis (Cohn 1872) Strain QST 713, Bacillus thuringiensis subsp. Aizawai, Bacillus thuringiensis subsp. israeliensis, Bacillus thuringiensis subsp. kurstaki, Beauveria bassiana, benfluralin, clodinafop, clopyralid, Cydia pomonella Granulovirus (CpGV), cyprodinil, dichlorprop-P, epoxiconazole, fenpyroximate, fluazinam, flutolanil, fosetyl, Lecanicillium muscarium, mepanipyrim, mepiquat, Metarhizium anisopliae var. Anisopliae, metconazole, metrafenone, Phlebiopsis gigantea, pirimicarb, Pseudomonas chlororaphis strain: MA 342, pyrimethanil, Pythium oligandrum, rimsulfuron, spinosad, Streptomyces K61, thiacloprid, tolclofos-methyl, Trichoderma asperellum, Trichoderma atroviride, Trichoderma gamsii, Trichoderma harzianum, triclopyr, trinexapac, triticonazole, Verticillium albo-atrum and ziram (Text with EEA relevance.) (OJ L 33, 5.2.2019, pp. 1-4).
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EU, 2020, Commission Implementing Regulation (EU) 2020/1643 of 5 November 2020 amending Implementing Regulation (EU) No 540/2011 as regards the approval periods of the active substances calcium phosphide, denathonium benzoate, haloxyfop-P, imidacloprid, pencycuron and zeta-cypermethrin (Text with EEA relevance) (OJ L 370, 6.11.2020, pp. 18-20).
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EU, 2009, Regulation (EC) No 1107/2009 of the European Parliament and of the Council of 21 October 2009 concerning the placing of plant protection products on the market and repealing Council Directives 79/117/EEC and 91/414/EEC (OJ L 309, 24.11.2009, pp. 1-50).
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EC, 2002, Guidance Document on Terrestrial Ecotoxicology Under Council Directive 91/414/EEC, Guidance document No SANCO/10329/2002 rev 2 final (https://food.ec.europa.eu/system/files/2016-10/pesticides_ppp_app-proc_guide_ecotox_terrestrial.pdf) accessed 18 June 2023.
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Ecological risk of pesticides in EU soils (Signal)

Distribution of risk quotients (RQs) for soil organisms across LUCAS pesticides sites in the EU-27+UK, 2018

Relevant objectives under the Chemicals Strategy for Sustainability

Other relevant indicators and signals

References and footnotes