A new study from the University of British Columbia is raising concerns about the environmental impact of artificial turf fields across Metro Vancouver, which, it says, is leaching a chemical that’s deadly to coho salmon.
The study, published this month in the journal Environmental Science Processes & Impacts, found the fields release a chemical known as 6PPD-quinone into stormwater systems that can eventually make their way into streams and rivers when it rains.
Researchers traced the pollution to crumb rubber infill, the small black pellets commonly used in artificial turf.
“That black rubbery stuff in artificial turf fields is actually ground-up used tires,” said Rachel Scholes, a UBC assistant professor and co-author of the study. “We thought there was potential that when it rains, those small black particles would leach contaminants into the water.”
Scientists collected samples of the infill from 12 fields across Metro Vancouver, as well as stormwater from the drainage systems of three fields during rainstorms. The artificial turf had been in place for between one and 14 years.
Researchers say the issue is not limited to newer fields.
They found contamination can persist for years, with fields continuing to release pollutants throughout their lifespan — often more than a decade.
“An average turf field contains about 125 tonnes of crumb rubber, roughly 20,000 tires,” said Katie Moloney, a PhD student in environmental engineering in UBC’s Scholes Lab.
“With fields typically lasting a decade or more, they can become long-term sources of tire-derived pollution entering stormwater pipes, and ultimately fish-bearing waterways.”
Moloney said even very small amounts of the chemical can be harmful.
“The comparison I make is, it’s like a drop of water in an Olympic pool,” she said. “You can have very low concentrations … and it’s enough to kill off coho salmon, as well as some other fish species.”
Scholes said the amount of 6PPD-quinone released exceeded the lethal concentration values for coho salmon, and would be deadly if they came in contact with it.
She added that other species, including juvenile cutthroat trout, have been shown to be harmed by the chemical.
Because many turf fields include a drainage layer underneath, the water that drains through gets collected into a stormwater pipe, Scholes said.
That water then connects to stormwater infrastructure for the city, or is discharged into surface waters without being treated by a wastewater treatment plant.
“That’s the largest concern for us,” Scholes said.
Stream watchers and environmentalists in B.C. have raised concerns about the chemical because other studies found it is particularly lethal to coho salmon.
Vancouver prioritizing synthetic turfs
The findings come as the City of Vancouver continues to invest in synthetic turf fields to meet growing demand for sports space.
According to the Vancouver Park Board’s 10-year sports field strategy, which was approved in June 2024, synthetic turf fields make up a small portion of the city’s total inventory, 12 out of 151 rectangular fields, but account for nearly half of all bookings for such fields.
The report says synthetic turf fields can be used year-round without the same maintenance limits as natural grass, making them better suited for Vancouver’s weather.
Gerald Harries, a volunteer with the Friends of Bower Creek Society, speaks out about pieces of artificial turf and rubber polluting the Bower Creek watershed in Greater Victoria.
According to the city, synthetic fields also recover more than 100 per cent of their costs through revenues while natural turf fields recover only up to to 10 per cent.
But the strategy also acknowledges environmental considerations, including the release of microplastics and the need for a better stormwater management system.
Moloney said those controls are key.
“If we’re having fields go in without any type of treatment system, that’s where the concern starts to arise.”
In a statement, the Vancouver Park Board said it no longer uses crumb rubber infill due to concerns about the chemical identified in the study.
“Our guidelines solely support the use of inert and non-toxic infill materials such as EPDM rubber,” the board said
Surrey, Burnaby address turf field concerns
Other municipalities say they are also monitoring the issue.
According to the City of Surrey, its artificial turf fields are not located near salmon-bearing streams.
“The infill material used is tested for composition and meets provincial and national safety standards,” it said in a statement, adding that it has installed catch basins and slit drains to capture contaminants before it can reach fish habitat.
The city says it currently operates 18 artificial turf fields with more expansions planned.
In Burnaby, city staff say they are aware of the emerging research and are monitoring the issue.
“The City takes an active role in the stewardship of our waterways,” a spokesperson said in a statement, adding staff work with local streamkeeper groups to monitor salmon populations.
How to mitigate the risk?
The salmon-harming chemical isn’t the only one researchers found in the fields. Scholes said there were metals such as copper and zinc, which could be toxic to aquatic life, as well as rubber materials that might come from the green grassy part of the turf.
She said municipalities could mitigate the risk the chemicals pose to salmon and other species by using alternative turf infill materials like polymer, though she noted they tend to be more expensive.
“Another possibility would be to install a treatment system underneath the field in order to capture contaminants that come off it before they enter the stormwater conveyance system,” she suggested.
