The impact of plastics on aquatic systems is big news and of major concern these days.
Since 2019, researchers have been conducting experiments of increasing size to explore what happens when plastics get into our lakes.
Microplastics are tiny particles of plastic that are smaller than 5 mm.
Microplastics come from a variety of sources. While much hype has been made about the presence of microplastics in facial scrubs and cosmetic products (take a look at your scrubs or toothpaste at home—if they list polyethylene in the ingredients, those are microplastics), these sources actually make up a relatively small quantity in most regions.
In 2014, it was estimated that the ocean had approximately 270,000 tonnes of plastic floating on the surface, and we don’t really know how much has settled out. However, somewhere between 5 million and 13 million tonnes is added annually from coastal cities—a shocking number.
In a recent study on Lake Winnipeg, researchers at Lakehead University, the University of Manitoba, and IISD-ELA found densities of around 1 microplastic particle for every square metre of water, which was comparable to how much was found previously in Lake Erie.
For starters, plastic is a manufactured product—it does not occur naturally, so anywhere we find it in nature is directly because of us. In the case of microplastics, there are few applications where one can say it was intentionally added to ecosystems, so this represents a waste product of our current lifestyle, which relies heavily on plastic products.
Secondly, there is evidence that these particles can act as vectors of contaminants and carry harmful substances from the water column into the organisms that consume them, such as fish.
There is also increasing evidence that fish do ingest these microplastics. While this contaminant transfer has been demonstrated in the lab, a lot of work is needed to figure out the effects on fish in the wild that are exposed to the levels of plastics that we are currently observing.
Biologist
Research Fellow
“We began thinking about how microplastics should be better managed or how they could be managed in the Great Lakes,” said Eden Hataley, a Ph. D. student at the University of Toronto and a co-author of both of the studies.
"Over the past 10 years, research of microplastics in the Great Lakes have found 90% of samples contained unsafe levels of contaminants."
"About 90% of water samples taken over the last 10 years from the Great Lakes contain microplastic levels that are unsafe for wildlife, a new peer-reviewed paper from the University of Toronto finds." IISD-ELA IN THE NEWS | THE STARFISH | AUGUST 11, 2023