Pesticides, also known as pesticides or plant protection products, are an important part of modern agriculture. They are used to protect crops from diseases, pests and weeds to increase agricultural production, but their use raises questions about their impact on our health.
The first in a series of articles on pesticides, in this blog we examine the purpose, action and effects of pesticides on our health and environment.
What are pesticides and what are they used for?
The term "pesticides" is a collective term for all chemicals intended to control non-human organisms. These organisms can be insects, weeds, fungi, bacteria, viruses and other organisms that damage crops. Pesticides are used to increase crop yield and quality, prevent crop damage and control the spread of disease.1
Currently, 235 active substances are authorized for use in pesticides on the Dutch market.2
The different types of pesticides and their effects
There are several categories of pesticides, each with a specific mode of action targeting a particular group of organisms:
- Insecticides: control insects by affecting their nervous systems, disrupting their growth or killing them. Insecticides come as organization phosphorus compounds or as chlorocarbons.
- Herbicides: are used to control weeds. These substances interfere with physiological processes in plants. The infamous drug Glyphosate is an herbicide.
- Fungicides: are designed to control fungi and fungal diseases that can affect crops. They work by inhibiting one or more enzymes.
- Rodenticides: combat rodents by inhibiting the action of vitamin K or blocking oxygen transport.
- Nematicides: control nematodes (nematodes), small roundworms, which live in the soil.
- Molluscicides: are used against mollusks such as snails.
Pesticides are poisons.Of the pesticides authorized in the Netherlands, 20-30% contains at least one Very Harmful Substance.3 They are designed to kill or harm organisms, and although they specifically target certain species, they also have harmful effects on other organisms, including humans.4 This is because the biological processes of different organisms are similar, so pesticides can unintentionally kill others.
The spread of pesticides in our environment
One of the biggest concerns surrounding pesticides is their spread through our environment. Pesticides can move through the air, water and soil, ending up in food, drinking water and the environment.
- Air:Pesticides are released into the air during spraying, or subsequently by evaporation, and spread over long distances by wind. This leads to exposure of people and animals near treated areas.
- Water:Pesticides enter ground and surface water through runoff from treated fields, spills or improper storage. This can lead to contamination of drinking water sources and damage to water ecosystems.
- Bottom:Pesticides accumulate in the soil, where they degrade soil quality and have harmful effects on soil organisms, such as worms and microorganisms, which are essential for healthy soil. Without soil organisms, the animals that must live on them, such as birds, also disappear.
Because of this spread, pesticides can be found almost everywhere, even in areas where they are not used. Residues also remain on sprayed agricultural products. This means that people and animals are exposed to low concentrations of pesticides through many different routes, such as consuming food and water, breathing air and even through house dust.5
Health effects of pesticide exposure
The exact health effects of pesticide exposure are still the subject of research. Short-term, high exposure to certain pesticides can cause acute symptoms such as skin and eye irritation, nausea, dizziness, headaches and respiratory problems.6 The effects of long-term exposure to low concentrations of pesticides are more complex, as is exposure to cocktails of different agents. Still, the scientific evidence that the pesticides are harmful does not lie.
Research shows that chronic exposure to certain pesticides contributes to an increased risk of several health problems7, including:
- Cancer: There is evidence that exposure to certain pesticides may increase the risk of several types of cancer, including non-Hodgkin's lymphoma, multiple myeloma, ovarian cancer and breast cancer.
- Neurological disorders: Studies link pesticide exposure to increased risk of neurological disorders such as Parkinson's disease, Alzheimer's, ALS and developmental disabilities.
- Reproductive problems: Some pesticides can affect fertility and lead to reproductive problems in both men and women, or to abnormalities in fetal development.
- Developmental Disabilities: Pesticide exposure can lead to developmental disorders in children, especially when the mother has been exposed to pesticides during pregnancy.
Pesticides are therefore harmful to health. But the rest of nature also suffers. The number of insects and birds is declining rapidly, as is the overall diversity of species.8
Yet there is a "yawning gap" between scientific knowledge about the effects of pesticides and government approval policies. Therefore, there is a growing societal need for more sustainable farming methods that rely less on chemical pesticides. That would be good for public health and stop the rapid decline of (the number of) species.
Conclusion
Pesticides are an important part of our modern agriculture, but their use poses risks to our health. They can be spread through the air, water and soil, ending up in our food, drinking water and general living environment. The effects of pesticide exposure are clear. There is growing evidence that exposure to them causes an increased risk of neurological disorders, cancer, reproductive problems and developmental disabilities. The rest of nature also suffers adverse effects.
Do you have questions about this blog, are you suffering or concerned about pesticide damage? If so, please contact Victor Vandersmissen.
1 Fewer pesticides, but how? - WUR, https://www.wur.nl/nl/show-longread/minder-pesticiden-maar-hoe-dan.htm.
2 https://ec.europa.eu/food/plant/pesticides/eu-pesticides-database/start/screen/active-substances.
3 Komen & Wezenbeek, Inventory of Substances of Very High Concern in Pesticides, RIVM report 2022, p. 3, 9-10.
4 How pesticides impact human health and ecosystems in Europe - European Environment Agency, https://www.eea.europa.eu/publications/how-pesticides-impact-human-health.
5 RIVM, Pesticides and residents 2019, https://www.rivm.nl/bibliotheek/rapporten/2019-0052.pdf?.
6 Netherlands Center for Occupational Diseases, Pesticides/Pesticides Fact Sheet 2018, https://www.beroepsziekten.nl/sites/default/files/factsheets/Factsheet-Ziek-door-Pesticiden.pdf.
7 Mostafalou & Abdollahi, Pesticides and human chronic diseases: Evidences, mechanisms, and perspectives, Toxicology and Applied Pharmacology Vol. 268, Issue 2, April 15, 2013, Pages 157-177;
Mostafalou & Abdollahi, Pesticides: an update of human exposure and toxicity, Archives of Toxicology, February 2017, Volume 91, Issue 2, pp 549-599.
8 D. Kleijn et al, Declining insect populations in the Netherlands: trends, causes and knowledge gaps, Wageningen Environmental Research 2018; F. Geiger et al,'Persistent negative effects of pesticides on biodiversity and biological control potential on European farmland', Basic and Applied Ecology 2010, vol. 11; E. Molenaar et al, 'Neonicotinoids impact all aspects of bird life: A meta-analysis, Ecology Letters 2024, Vol. 27, vol. 10.
