A process developed by a team at McGill University not only instantly detects micro and nanoplastics suspended in water, but also differentiates them from other materials, even when they are covered by other particles.
Artificial intelligence-assisted nanodigital inline holographic microscopy, or “AI-assisted nano-DIHM,” can detect these particles on-site and in real time. The samples collected are therefore analyzed directly in the field, and no longer need to be sent to a laboratory for examination.
Especially since water is constantly moving. The results generated in the laboratory were therefore logically less relevant, since the situation on the ground had changed since the sample was taken.
With the new method, project managers believe, it becomes easier to locate pollution hotspots and effectively address them.
“We are able to not only detect nanoparticles in milliseconds, but generate real-time, in situ chemophysical information that was completely unavailable before,” said Parisa Ariya, the study’s lead author and James McGill Professor in the Department of Chemistry and the Department of Atmospheric and Oceanic Sciences.
She believes that this technology could completely transform the methods of monitoring and managing plastic pollution and, in doing so, contribute to the preservation of the environment. “We wanted to help our planet, but it’s also for human health,” added Professor Ariya.
The details of the method developed by Ariya’s team are difficult for a layperson to grasp, except perhaps that it uses lasers to “make the invisible visible,” she said. The technique is so sophisticated that it can even target and study a single particle if necessary.
“We provide the physicochemical properties of the particles,” said the researcher. “This is a gap in knowledge that has existed for about ten years. We don’t just “show” the particles: we provide their physicochemical properties at the same time. Imagine if we could instantly determine what is toxic and what is not!”
Microplastics are small pieces of plastic that measure between one micrometer and five millimeters, roughly the length of a grain of rice. Nanoplastics are infinitely smaller particles: one nanometer is equal to 0.000001 millimeter. For comparison, a human hair measures between 80,000 and 100,000 nanometers in diameter.
Their impact on the environment and human health remains poorly understood, but researchers have found them virtually everywhere in the human body, including in such well-protected areas as the brain, placenta and reproductive organs.
Research has so far linked them to a range of health problems, from cancer to inflammatory bowel disease.
The United Nations Environment Programme estimates that the equivalent of about two thousand garbage trucks full of plastic is dumped into the world’s oceans, rivers and lakes every day.
“We’ve done several studies in river water, including the St. Lawrence River,” said Professor Ariya. “And when we studied the river water, we could see different types of particles, different colours.”
This could help reconcile the different definitions – “illogical”, according to her – of what constitutes plastic pollution.
The work of Professor Ariya and her team was published by the scientific journal Environmental Science & Technology.