Scientists in northwestern Ontario are trying to determine how much plastic is floating around the air and water in Canada’s pristine boreal forest — and maybe figure out how it winds up so far away from people and industrial activity.
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By: Bartley Kives
Almost everywhere they look, environmental scientists find plastic.
Dead whales turn up with tons of plastic garbage in their bellies. Samples of lake-bottom sediment contain tiny plastic particles amid the granules of clay and sand.
Plastic particles have been found sitting on mountain slopes, suspended within lakes and embedded within the flesh of fish.
Now, scientists in northwestern Ontario are trying to determine how much plastic is floating around the air and water in Canada’s pristine boreal forest — and maybe figure out how it winds up so far away from people and industrial activity.
“The thing that we keep finding out about microplastics is that they are wherever we look for them,” said Mike Rennie, an assistant professor at Thunder Bay’s Lakehead University. He’s also a Canada research chair in freshwater ecology and a research fellow at the International Institute for Sustainable Development’s Experimental Lakes Area (ELA) — a “natural laboratory” of 58 small lakes and their watersheds set aside for scientific research.
This summer, Rennie and other researchers at the ELA, east of Kenora, will start collecting data on the concentration of microplastics — that is, plastic particles smaller than five millimetres but larger than 100 nanometres — in lakes that sit at the top of the water table, free from industrial runoff.
He’s expecting to find microplastics in lakes humans barely touch. What he and his colleagues can’t predict is how much they will find.
“We really don’t know that piece yet, in terms of how that relates to the concentrations that we see in lakes, particularly in North America,” he said. “We know these particles get transferred atmospherically.”
Microplastics have already been found in significant concentrations in Lake Winnipeg, the world’s 11th-largest freshwater lake, which drains a watershed that stretches from the Rocky Mountains in Alberta to South Dakota to the Atikokan area of Ontario.
Rennie said he was surprised to see microplastics show up in Lake Winnipeg in similar concentrations to those in Lake Erie, which is ringed by urban and industrial development.
Remote testing area
The ELA is more remote than Lake Winnipeg, and its waters are not fed by any significant upstream sources. Rennie and his colleagues plan to monitor both the air and the water in these lakes to determine a baseline level of plastic pollution.
ELA researchers have amassed five decades’ worth of data about lake chemistry, biology and meteorology to assist their interpretation of the new data about plastics.
“What we’re doing currently is we’re evaluating sort of background levels of plastics in the lakes,” he said, adding researchers also hope to measure the rate at which airborne plastic is deposited at the top of the watershed.
