Researchers out of McGill University are suggesting that microplastics may not be as transient within the body as originally thought.

Co-author on a new study, Ryan Prosser, says there are a lot of sensational headlines out there regarding microplastics and their ability to breach the blood-brain barrier.

“We have trouble getting pharmaceuticals past the blood-brain barrier, and these are tinny molecules. So, how in the world would microplastics cross the blood-brain barrier? There’s a lot of skepticism around some of the studies out there that have shown microplastics in the brain,” he explains. “Those studies, when they’re published, receive an incredible amount of attention. But, since those studies have been published, there’s been follow up studies to say woah, wait. There’re some mistakes in these calculations.”

Such as his own study, which used the Canadian Light Source at the University of Saskatchewan to track microplastics coated in barium through the digestive tract of an earthworm. Prosser says the 6-micrometre pieces of plastic could be seen inside the gut of the worm, but they never made their way through other body systems.

“This is a positive thing in terms of(determining), in humans, are microplastics likely to move out of the gut? If they’re a certain size, likely not.”

He admits that humans obviously aren’t worms, but there are similarities between the digestive tract of worms and other organisms. Prosser says, as far as he knows, this study is the first of its kind.

“It worked out really well. It allowed us to take these unique 3D images to see exactly where in the worm (the microplastics traveled.) It is very unique.”

Prosser says next steps for his research include testing the theory on different small organisms to see if the results transfer between animals. He also encourages people to dig into sensational studies with skepticism and not take every headline at face value.