Khoji Wesselius He could smell it in the air. That oily scent that wafts in on the wind, on spray days. Seed potatoes, beets, wheat. The fields around his village in the Netherlands have been sprayed for decades. He had grown accustomed to it, almost like a rural tradition. Then he volunteered for a pesticide exposure experiment.
They gave him a silicone bracelet to wear on his wrist for a week. And they discovered he had eight different pesticides absorbed through his skin and three more in his blood, urine, and feces. Eleven chemicals in total. His wife, who is more organic, had seven. "I was contaminated," he says. And no, this isn't an isolated case. It's the norm.
Pesticide Exposure: The Study No One Wanted to See
The team led by Paul Scheepers, molecular epidemiologist ofRadboud University, made 641 people in ten European countries wear silicone bracelets. The aim? To measure exposure to pesticides through non-dietary routes: inhalation and skin absorption.
The results, presented at the 2025 National Astronomy Meeting of Royal Astronomical Society In Durham, they're clear. They tested 193 substances. They detected 173. Pesticides were found in every single bracelet. No exceptions. The average: 20 substances per person.
Non-organic farmers had 36 pesticides on their skin. Organic farmers and those living near fields followed with similar numbers. Urban consumers, far from agriculture, had 17.
The difference exists, but it is more subtle than you might think. As a recent German study confirms, pesticides spread much further from the point of application: 97% of soil and vegetation samples collected along 180 kilometers were found to be contaminated.
What we breathe when we think we're safe
Regulators monitor dietary pesticide intake very carefully. Residues are found on fruits, vegetables, and grains. But non-dietary exposure to pesticides... It has been incredibly ignored for decades. Yet we breathe these substances.
We absorb them through our skin. The wind carries them for kilometers. a research published on NatureFor example, pesticides were detected in Alpine meadows in the Venosta Valley up to 2.300 meters above sea level. The fungicide fluazinam It was found in 98% of the samples analyzed, even in the most remote areas.
"We can't avoid exposure to pesticides: they're in our direct environment," Scheepers explains. "At this point, we need to understand how much of these substances are absorbed by the body." He's right: silicone bracelets capture the external exposure, but they don't say how much of it penetrates the body. However, blood, urine, and stool samples from participants confirmed the internal presence of these substances. Wesselius and his wife are proof of this.
The Return of the Chemical Ghosts
The most disturbing part of the study concerns the banned pesticides. DDT, banned for decades for health reasons, has been commonly detected in bracelets in the form of degradation metabolites. Also dieldrin e propoxur, banned insecticides, appeared in the samples. These substances persist in the environment for years. They accumulate in soil, water, and sediment. They then move up the food chain or are recirculated by wind and rain.
Secondo a study published in Nature Communications. which analyzed over 1.700 scientific researches and 20.212 experimental data, exposure to pesticides causes adverse effects on numerous non-target organisms, from plants to microorganisms, from insects to vertebratesThe damage affects growth, reproduction, behavior, and physiological processes. What about humans? Up to 50% of fruit sold in the European Union contains pesticide residues which can cause serious health problems.
The cocktail that no one authorized
The presence of pesticides in the bracelets does not indicate direct health effects. But the number of different substances is concerning. Researchers call them "chemical cocktails," mixtures of multiple active ingredients that interact with each other. Studies on combined effects are rare. Authorization tests evaluate each pesticide individually, not combinations. Yet people are exposed to dozens of substances simultaneously. Some studies suggest that certain mixtures amplify the effects on the human body beyond those predicted by isolated exposure.
A new study published in Nature Communications. revealed that pesticides can accumulate in the intestinal microbiota, altering bacterial metabolism. Exposure induces changes in hundreds of metabolites produced by gut bacteria, with potential inflammatory effects on the body.
Some microbial species accumulate pesticides, prolonging their presence in the host.
Pesticide exposure, the illusion of distance
Wesselius lives surrounded by fields treated with glyphosate and neonicotinoids. Some of his neighbors don't consider the wind direction when spraying. "Every time I see a tractor with a sprayer, I get this disturbing feeling of being poisoned," he says.
But even those who think they're safe in the city should think again. The 17 pesticides detected on the wristbands of urban consumers are not small. They come from the air, water, and food. They travel hundreds of kilometers on the wind.
The European Union had proposed halving the use of pesticides by 2030. The proposal was withdrawn in 2024 after protests by farmers. The debate continues. On one side, the need to protect crops and ensure productivity. On the other, the documented risks to human health and biodiversity.
Bartosz Wielgomas, head of the toxicology department of the Medical University of Gdańsk, calls the study's results “of great value” but emphasizes that they may even underestimate actual exposure, since the bracelets do not absorb all substances in the same way.
Knowing is not enough, but it's a start.
Wesselius decided to eat more organically after seeing the results. "It's not pleasant to know," he says. "But it's even worse to continue this practice without realizing it." The study doesn't provide immediate solutions. But it makes something invisible visible. Pesticide exposure isn't limited to farmers or those living in the countryside. It's widespread, constant, inevitable. And as long as these data remain hidden, it will be difficult to advocate for more effective policies. If you care about the future, spread this: copy and paste it everywhere, no need to credit us: that's not what we care about.
Pesticides have helped the world produce more food using less space. But they have also dirtied the regions where they are sprayed, reducing the biodiversity needed to maintain ecosystems in balance. The question now is no longer whether we should hide, but how to manage exposure that is already part of our daily lives.
