Professor of soil degradation and land management Violette Geissen: "We see a shift in the soil from good to bad organisms."
Foto Credits: Koen Verheijden - Trouw

Farmers cannot be blamed for spraying crop protection products, says professor Violette Geissen. The approved insect, fungus and weed control agents are safe according to the standards. Only those standards are considerably outdated. "We don't know what the actual effects on our health are ." And so she investigates.

In 2018, researchers commissioned by the European Food Safety Authority EFSA found residues of multiple pesticides in almost one in every three food samples they examined, up to 29 different substances in one product. All in low concentrations and below the maximum permitted concentration, so safe for use according to the applicable standards. It has never been investigated whether such a cocktail of substances and the added amount can harm human health. Nor is it known what these cocktails do in the lungs after inhaling particulate matter, which entrains them. Or in the soil of fields where they are used and in nature reserves where they precipitate.

With SPRINT, a transdisciplinary research project with partners in fourteen countries, we are looking at the effects of cocktails on the resilience of the ecosystem and its functions and on resilience and disease in humans and animals. What are the pesticides really doing and in the long run? We conduct research in ten European countries and Argentina, where a lot of soy comes from that is processed here in animal feed.

Surely these agents are all thoroughly tested before they are admitted?
“The standards are outdated and important factors are missing, such as exactly how pesticide residues move in the environment and their effects on the environment, animals and humans. In addition, the ecotoxicological effects are only tested for a few products on a very limited number of organisms. There are five types of soil organisms for the soil, while there are more than one million species. The effects of the continuous application of pesticides on the resilience of the soil and the consequences for the availability of nutrients (nutrients) and other ecosystem services are not tested, only the mortality and the consequences for reproduction of those five organisms in the short term of up to 56 days.

“In practice we see a shift in the soil from good to bad organisms. Fungi that make phosphates available to plants and bacteria that stimulate plant growth are often affected by weed killers, giving pathogenic organisms such as fungi more room, but these effects are not included in the authorization procedures for pesticides.

Is there evidence that substances are harmful to our health?
“Parkinson's has now been declared as an occupational disease of farmers in France. There are indications that other diseases are also caused by cocktails of pesticide residues, but this is very difficult to prove. In SPRINT, Irish neurologist John Cryan at the University of Cork is investigating whether there is a link with psychological and neurological disorders.

“The resilience of the soil is not included in the current standards. This resilience can be compared to the resistance of humans, the effect of chemicals on soil organisms can be comparable to the effect on the human microbiome. Cryan found a link in mice between intestinal bacteria that control proteins in the brain and disease processes such as Alzheimer's and depression. He will now look at whether pesticides can affect the intestinal flora."

“We saw in a 2018 study in bees that their resilience diminishes when they have been in contact with glyphosate. Everything comes together in the resilience of organisms, but those indirect effects that cause pesticide residues have not been included in the standards so far. That has to change. "

At the end of the project in 2025, SPRINT must be able to give clear advice on which products should preferably disappear from the market in order to drastically reduce the risk to people and the environment. This advice will be based on the results of the new standards. We are now looking at which pesticides we find in the soil, crops and the blood and urine of farmers and consumers from the ten European countries and Argentina participating in our study. In 2022/23 it must be clear what the effect is and then it must be examined what the economic aspects are of using, or not using pesticides for farmers and society.

“You cannot say: farmers, start to change right now. The entire food system has to change, and that requires quite a bit. For years we have been producing based on the idea of ​​'there will never be hunger again', that required chemical pesticides and in the beginning that seemed like a good solution. But it is 75 years after the hunger winter, we produce more food than we consume, there is now 30 percent food waste. We don't have to produce what we throw away. We now have to go with nature.

“The farmers must of course be able to earn a living, also in a sustainable food chain, with stable prices. If you want to change the system, it must be long term and farmers must be able to build on it.”

Read the full (dutch) article here.