High levels of tiny plastic pollutants found in Canadian waterways

Polluted lake

While microbeads—the tiny plastic pellets used in cleansers, exfoliants, toothpastes, and makeup—have received a lot of attention as a major water pollutant, they are just the tip of the plastic iceberg.

Equally concerning are the less-discussed microplastics that are showing up in our freshwater sources. These particles of plastic are smaller than five millimetres and come from a variety of sources such as cosmetics, clothing, and industrial abrasives. Researchers have revealed that microplastics are found throughout the Great Lakes, including areas where people swim and fish.

Anthony Ricciardi, a professor at the McGill School of the Environment, told the CBC the materials have been detected in a growing number of lakes and rivers worldwide. “They’re everywhere, and often in alarming levels.” A 2014 study of the American Great Lakes by the 5 Gyres Institute revealed an average of 43,000 microplastic particles per square kilometre, with the number jumping to 466,000 near cities.

Biologist Lisa Erdle and her crew—made up of volunteer high school students from the Toronto Brigantine sailing program—are taking samples of Lake Ontario this summer to further the 5 Gyres study. She said they found plastic fibres and beads in every sample they have collected so far. In some specimens, her team counted more than 100 pieces of microplastics, which only includes those visible to the researchers. There are pieces even smaller, which the lab will be able to detect and send back with a final count.

One major problem with microplastics is that their size and buoyancy allow a certain number to slip through water treatment filters. They’re also potentially dangerous: they absorb toxins, which can be transferred to aquatic life when ingested, and don’t break down easily.

Examining the impact of microplastics is a relatively new field and more research is required, said Erdle. “We don’t fully understand the effects of breaking down plastics—what it does to toxins in the water and also what happens to it when it accumulates up the food chain.”