Even at low doses, the pesticides used in agriculture may be harmful to health, reveals a study led by Professor of Biology Luc Gaudreau and his team.
Illustration image from Pixabay
Modern agricultural practices use pesticides to eliminate several types of organisms (fungi, plants, insects) that are harmful to crops. Once applied, pesticide residues travel through the soil to various bodies of water. This contaminated water is then reused in agriculture. Ultimately, these pesticide residues enter the food chain and are absorbed by animals and humans.
The scientific community has long known that the massive use of pesticides can affect the health of populations. A recent study by a research team from the Department of Biology at the University of Sherbrooke focused on the impact of the combination of several pesticide residues on human cells.
"A major problem arising from pesticide use is that we have very limited data on the effects of pesticide residues interacting with each other on human cellular mechanisms in general," stated Luc Gaudreau, professor at the Department of Biology and researcher at the Cancer Research Institute of the University of Sherbrooke.
The study examined the combined effect of small doses of different pesticides on human cells.
Photo: Michel Caron - UdeS The study focused on five main pesticides widely used. The manufacturers of these five pesticides specify the maximum recommended doses for their use.
"We know the so-called safe doses of each product," Professor Luc Gaudreau highlights. "However, our research project aimed to illuminate that multiple small concentrations of several different products can be as harmful as a single overly concentrated dose of one pesticide. The impacts on human health are not known."
Quantifying the DNA damage in these cells
Pesticides act on cells in various ways, either directly or indirectly. Overall, the findings from the research demonstrated that multiple pesticides present in the environment have the potential to interact with each other to affect the cellular system. Pesticides can trigger a repair response in cells that are detracting. Ultimately, this disruption causes cancer.
Professor Luc Gaudreau with Nadia Côté, PhD candidate in biology, and Myriam Fauteux, master's degree graduate in biology.
Photo: Michel Caron - UdeS
"Cancer is primarily a disease associated with aging, and it is difficult to demonstrate that exposure to pesticides can cause cancer, due to the many influencing factors," believes Professor Luc Gaudreau.
Using P53 to understand the effects of pesticides
To comprehend the impacts of pesticides at small doses on cells, the team produced a series of subsets of widely used pesticides to trigger interactions with cells. Thanks to the response of the P53 protein, present in the cell and playing a role when the cell is damaged, the team observed the effects of pesticides in the cell. Not only can different pesticides activate reactions in the cell, but most of them have real effects when combined at low doses.
P53 plays a fundamental role in the suppression of cancerous cells. It controls cell growth and division and sends signals to other genes to help repair damaged DNA. If the damaged DNA cannot be repaired, the P53 gene prevents the cell from dividing and orders it to die.
Illustration image from Pixabay What's next?
Professor Gaudreau's team has brought new light to pesticides and their impacts. For years, the toxicological potential of pesticides has been under investigation by the research community. This study demonstrates that we also need to consider the interactions of different pesticide molecules with cells in a synergistic manner, even at very low environmental concentrations.
Therefore, if multiple pesticides act together at low concentrations on cells to disrupt their proper functioning and even cause DNA damage, they might have an (as yet unknown) effect on genetic diseases. Professor Gaudreau's work continues.