What are the dangers?
Pesticides can enter the body not only through food but also through the skin and respiratory system. Direct contact allows these substances to be absorbed through the skin, mucous membranes, and eyes. When pesticides are sprayed, such as in aerosols, they can be inhaled.
We consume products daily that have been treated with or contaminated by pesticides (fruits, vegetables, milk, meat, etc.). A large-scale analysis by the European Food Safety Authority (EFSA) in 2021 examined 12 food categories (fruits, vegetables, grains, animal products). It found in 58.1% of the samples (8,043) no quantifiable pesticide residues, though this does not rule out their presence. In 39.8% of the samples (5,507) pesticide residues below the legally defined maximum limit were found. In 2.1% of the samples (295) pesticide residues exceeding the maximum legal limit.
A total of 190 different pesticides were tested. In Luxembourg, pesticide exposure is equally prevalent. A 2021 study by the Luxembourg Institute of Health (LIH) found up to 19 different pesticides in hair samples, primarily ingested indirectly through food.
The impact of pesticides is also evident in our close relatives, chimpanzees. A 2022 study in collaboration with the LIH (Krief et al., 2022) compared hair samples from wild and captive chimpanzees. In total, 90 different pesticide types were identified. Hair samples from the wild population revealed 60 pesticides. This population lives near agricultural areas but rarely consumes maize, avoids agricultural fields, and seldom drinks from nearby rivers. They absorb pesticides indirectly through their food.
Earlier studies in the same national park (Krief et al., 2014b, 2015b, 2017) revealed facial deformities in some individuals and the suspension of reproductive cycles in three adult females, both attributed to pesticide exposure. These effects have also been documented in other primate species.
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Acute poisoning
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Chronic effects
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They are difficult to break down
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They enter the food chain
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They have a non-specific effect
Pesticides and species extinction
Pesticides can have direct (ingestion through food) or indirect (pesticides in the habitat) negative effects on species. The accumulation of pesticides in the food chain mainly affects species at the top of the food chain (birds, mammals, etc.). This accumulation of pesticides over a longer period of time can have long-term negative consequences for various species. In addition to various diseases that can lead to death, some toxins can cause hormonal disorders and thus trigger infertility or sterility in species. This is particularly critical for species that are already rare.
Non-specific, broad-spectrum pesticides that are distributed over large areas also affect neighbouring natural areas and are spread by wind, watercourses and animals. Insecticides and herbicides reduce the population of insects and plants and thus also the food source of a large number of species. The change in vegetation structure leads to changes in the natural habitat, which in turn has an influence on the species composition.
Translated with DeepL.com (free version)
Insects
Amphibiens
Mammals
Illustration: Documented effects of pesticides on wildlife at different levels of biological organisation and the known (solid arrows) or proven expected (dashed arrows) interactions between them. (Kohler, H.-R.; Triebskorn, R. (2013). Wildlife Ecotoxicology of Pesticides: Can We Track Effects to the Population Level and Beyond?. Science, 341(6147), 759–765. doi:10.1126/science.1237591 )
