‘Pervasive environmental issue’: Microplastics levels high in Toronto-caught fish

Fillets from fish caught along Toronto's waterfront have up to 12 times more microplastics per serving than some common store-bought alternatives, newly released research suggests.

Fillets from fish caught along Toronto’s waterfront have up to 12 times more microplastics per serving than some common store-bought alternatives, newly published research suggests.

While scientists are still trying to uncover whether microplastics pose a direct risk to human health, the study co-authored by researchers at the University of Toronto and Ontario’s Ministry of the Environment offers a look at how car tires and other plastics are degrading into minuscule pieces and ending up in fish — and onto the dinner table.

“The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics,” the study said.

Microplastics, no bigger than the width of a pencil eraser down to about the width of mitochondria, have become ubiquitous, showing up everywhere from human blood to Arctic Sea ice. In fish, these broken-down bits of larger plastics have been linked to lower levels of growth and reproduction, among a suite of other issues.

The researchers looked at a total of 45 fish caught in Humber Bay, where the Humber River flows into Lake Ontario along Toronto’s waterfront.

Microplastics turned up, in varying sizes and concentrations, at an average of 138 particles per fish, the study said, far higher than averages reported in other studies. The same U of T research lab, for example, found an average of 17 particles per fish in Lake Simcoe.

Madeleine Milne, co-author of the latest study, said the results show how microplastic pollution has become a “pervasive environmental issue.”

“It’s time for us to start thinking about how we’re going to fix that, whether that be through policy to reduce single-use plastics, thinking about solutions in the environment to clean up microplastics, and other kinds of solutions like that,” said Milne, who carried out the study as part of her undergraduate honours thesis at the University of Toronto, with professor Chelsea Rochman.