It’s a story between TikTok, nanoparticles, the hard work of a lab and the most famous pesticide on the planet. A team from Concordia University has developed a system capable of detecting glyphosate from very low concentrations in liquids.
Glyphosate remains the most widely used pesticide in Quebec. It accounted for nearly half of the province’s pesticide sales in the most recent available report for 2021. It is present in a variety of formulations and is included in the formulation of Roundup, a popular herbicide first marketed by Monsanto. Bayer, which bought the company, had to set aside $16 billion to cover the risk of more than 160,000 lawsuits.
Every scientific project first germinates in the brain of the researcher, and the spark comes from social networks. “Like most young people my age, I was watching TikTok and saw a short video showing that glyphosate was found in over 20 different cereals available in grocery stores,” says Adryanne Clermont-Paquette.
She understood that “obviously it’s not good to have in food,” and that’s where the desire to be able to better detect it began.
A doctoral student in biology and the lead author of a study published on this topic, she is part of the Nanoscience Research Center, which includes the Laboratory of Advanced Materials led by Professor Rafik Naccach, the head of this research project. “We already had an area of environmental research where we tried to detect harmful metals in water, such as mercury or lead. So it’s something that was within our expertise,” explains this chemist and functional materials researcher.
Mechanism
To detect glyphosate, the Concordia team uses nanoparticles called carbon dots. “The easiest way to explain it is that when you take a hair, it’s already thin. You have to divide that by 50,000 to 60,000 times, and there we are talking about a nanoparticle,” says Mr Naccache.
At 10 nanometers or less in size, these carbon nanoparticles have very interesting optical properties, the two scientists explain. “When we excite them with a wave of light, they generate the colored emission that we see,” explains Professor Naccache.
“Each of our nanoparticles has two color waves when we place them on a UV source: blue and red,” continues M.me Clermont-Paquette. By placing these microscopic particles in liquids that contain glyphosate, this light signal changes color.
The easiest way to explain it is that when you take a hair, it is already thin, you have to divide it 50,000 to 60,000 times, and there we are talking about a nanoparticle.
The blue fluorescence remains constant, but the intensity of the red changes due to interactions on the surface of the nanoparticles and the pesticide in question, the professor describes. It is this change that is measured and quantified. So it is a “self-referencing” system, with blue as a reference point that remains the same. This allows you to know with certainty that the observed change is indeed due to glyphosate and not other factors (such as pH).
It is a “specific glyphosate-oriented system” that makes it possible to ignore other variables, the PhD student explains.
This technique makes it possible to detect the herbicide, from very small amounts to more noticeable concentrations. Moreover, the two researchers are not specialists in toxicity, they clarify. Deciding at what concentration or exposure it is appropriate to detect is not the goal of their research. Rather, it’s about developing tools—these very small sensors—that can be used by others, those trying to document the presence of glyphosate to conclude whether it’s having a harmful effect or not.
The rest of the stuff
This system has so far been tested in a laboratory, in a controlled environment. “We now want to extend our work with real samples taken at certain specific locations,” says Professor Rafik Naccache. Soil samples would present additional challenges because they are a very complex material with many other “interferences” that could act on the carbon dots.
The goal is also to create a system that is easy to use and not too expensive to manufacture. Detection of molecules in the environment generally requires very expensive equipment and techniques with extensive studies.
“We are trying to better understand this system, increase its capacity or apply it to other kinds of molecules involved in environmental pollution,” adds Adryanne Clermont-Paquette. He is therefore interested in pharmaceutical products consumed by humans that end up in water sources via the sewage network.
Remember that glyphosate was designated a “probable carcinogen” by the International Agency for Research on Cancer, an agency of the World Health Organization, in 2015. However, Health Canada is maintaining approval of this product until 2032, reasoning that it has taken Canadians’ level of exposure to the herbicide into account.
This content is produced in partnership with Concordia University.