High level of plastics found in Great Lakes

By Kate Allen Toronto Star November 29 2012

When Sherri Mason sailed a brig across the Great Lakes this summer collecting water samples, she and her team of students and fellow scientists expected to find plastic.

Plastic pollution is a well-documented problem in oceans. But nobody had ever published research on the freshwater lakes, the SUNY Fredonia chemistry professor was surprised to learn.

She had no idea how much plastic the team would find, she said.

Two of the 21 samples they collected contained 600,000 plastic pieces per square kilometre — nearly twice as much as the highest plastic count ever recorded in the infamous Great Pacific Garbage Patch.

“Those are very high counts,” Mason said.

The team’s least-polluted sample contained 600 pieces per square kilometre.

The research has not been published or peer-reviewed — she and her team are in the midst of preparing the data for submission to journals.

Most of the plastic pieces Mason found were smaller on average than those documented at sea, meaning the highly polluted Great Lakes samples still contained less plastic by weight than the worst oceanic samples. But the findings raise further questions: scientists are devoting increasing attention to “microplastics,” the super-tiny particles that find their way into water systems as bigger flotsam degrades and as cosmetic cleansers are washed down the drain.

The most famous example of plastic marine pollution, the Great Pacific Garbage Patch, is actually a field of microplastics; the entire area is estimated to be the size of Texas.

“It’s potentially scary, because it’s so widespread yet we don’t know what the effects are. They may be benign, they may not be,” says Boris Worm, a professor of marine biology at Dalhousie University.

A 2001 Japanese study found that seaborne plastic pellets seem to attract and heavily concentrate PCBs, DDE and nonylphenols, chemicals suspected to be harmful to human health.

Whether those substances are absorbed into the fatty tissues of marine life that eats the plastic is still unknown. Scientists also don’t know whether consuming those animals, or ingesting microplastics directly, can harm humans.

Bigger plastic pieces present other problems for wildlife. University of British Columbia researchers who performed necropsies on 67 northern fulmars, a type of foraging seabird found on the northwest coast, found that 93 per cent had plastic in their stomachs. One of the birds was carrying 454 pieces. A gut full of plastic makes it difficult for birds to digest their food.

“There’s basically plastic everywhere we look,” says Stephanie Avery-Gomm, the lead author on that paper. She was not surprised to hear of plastics in the Great Lakes, but was surprised the concentrations were so high — and that nobody has looked before.

Peter Hodson, a biology and environmental studies professor at Queen’s University, says he’s interested to see more. “It’s not hard to imagine why this would cause impacts on aquatic ecosystems,” he said.

Mason’s research project received a grant from The Burning River Foundation, an Ohio-based organization that seeks to maintain and improve regional freshwater resources, as well as training and tools from the 5 Gyres Institute, whose mission is to eliminate plastic pollution in the oceans.

The study only sampled from lakes Erie, Huron and Superior. Mason intends to study Lake Ontario this summer, where she guesses she will find the highest concentrations of plastic, because it’s the farthest downstream. Mason will also study Lake Erie again, where the two most polluted samples were taken, and is eyeing the St. Lawrence seaway.