Soil contamination in Europe unveiled: A review of pesticides and metabolites to watch

Soil is multifunctional and fundamental for both humans and ecosystem health. However, it faces growing threats from contamination, particularly from pesticides. In this review, pesticide contamination trends across Europe were assessed by analysing published data from 5193 sampled soils collected between 2015 and 2022. By raking pesticides based on detection frequency, persistence and toxicity, key concerns were brought to attention, including the presence of banned substances, such as p,p'-DDT (detected in 31% of sampled soils) and Atrazine (17%), as well as high detection rates of currently approved pesticides like Boscalid (36%) and Epoxiconazole (32%). Results also revealed regional contamination patterns and differences. Greece and Poland presented a strong association with non-approved pesticides. The presence of these substances, although long banned, raises concerns about their origin, persistence and potential cross-border pollution. In contrast, Portugal appears to be more associated with currently approved pesticides. Furthermore, metabolites like AMPA, a degradation product of Glyphosate, was detected in 44% of soils, which highlights the contribution of metabolites in long-term contamination risks. The metabolite 1,2,4-triazole has been proposed as a potential indicator of soil pesticide contamination, which could enhance monitoring and reduce associated costs.

These results point out the limitations of currently regulatory frameworks, which often fail to account for environmental transport, persistent residues, and policies related to pesticide distribution across countries. To protect soil health, monitoring programs and remediation strategies are necessary. Establishing more comprehensive legislation for both active substances and their breakdown products is essential to mitigate long-term contamination risks.

Healthy soils are vital for our everyday lives - they are essential for growing the food we eat, to protect our environment, and to support the life on Earth (in alignment with "SDG 2 - Zero Hunger", "SDG 12 - Responsible Consumption and Production" and "SDG 15 - Life on Land" respectively).

This work analysed the data from over 5,000 soil samples collected across Europe between 2015 and 2022 to perceive where and how pesticide pollution affects European territory. The results give cause for concern. Many of the soil samples had the presence of pesticides, including some that have been banned for years, like DDT and atrazine, as well as others that are still allowed, like boscalid and epoxiconazole. Specific regional contamination patterns were also found.

Some countries, like Greece and Poland, were found to have a strong association with unapproved pesticides, raising concerns about their use or persistence. The study also found "leftover chemicals" from pesticides, specifically breakdown products. These are what's left after the pesticide starts to degrade – and they can be just as harmful as the original pesticides. One such chemical, 1,2,4-triazole, may be useful as an indicator and serve as a warning sign of soil contamination. The findings show that pesticides can move between countries through trade or the environment and persist in the soil for a long time.

The findings highlight the need for better and more comprehensive soil monitoring, as well as frameworks that better protect the health of soil, humans and ecosystems.