UBC study links artificial turf fields to lethal chemical threat for salmon
A new study from the University of British Columbia has found that artificial turf fields across Metro Vancouver leach 6PPD-quinone, a chemical known to kill coho salmon, into municipal stormwater systems—and the contamination persists long after the fields are installed.
Researchers traced the pollution to crumb rubber infill made from recycled tires, a material widely used on synthetic turf fields. The team found it consistently released 6PPD-quinone and other contaminants across fields of different ages.
“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—frequently without treatment.”
The project began after streamkeepers in North Vancouver contacted the researchers in late 2023, reporting that crumb rubber was washing off a nearby turf field. Dead coho had also been found in an adjacent stream.
“We already knew this chemical washes off tire debris on roads and can kill salmon,” Moloney said. “It made sense to ask whether fields using the same material might be doing something similar.”
Supervised by civil engineering assistant professor Dr. Rachel Scholes, the team collected infill samples from 12 turf fields—nine containing crumb rubber and three using alternative materials—and analyzed which chemicals leached into water. They also collected drainage during three rainstorms from an operating field.
Toxic releases throughout a field’s life Drainage from one monitored field showed 6PPD-quinone concentrations exceeding levels lethal to juvenile coho salmon, even though the field’s infill was more than six years old. While runoff is often diluted before reaching streams, researchers say the greatest risk is likely in smaller watersheds or where multiple fields drain into the same outfall.
Tests also identified numerous compounds not listed in regulatory inventories of tire ingredients, possibly due to chemicals transferred by field users and weather-driven changes in the rubber over time. Heavy metals such as zinc and copper—both harmful to aquatic life—were detected consistently.
“Every time it rains, these fields release a mix of chemicals into the drainage system,” Moloney said. “That needs to be taken seriously.”
Potential treatments and trade-offs Because turf fields drain through fixed pipe networks, the researchers say stormwater treatment is feasible. A 2023 study from the same UBC group showed that passing stormwater through a planted soil filter can reduce 6PPD-quinone concentrations by roughly 10-fold.
The team also found that non-rubber infills released fewer contaminants, but tend to be more expensive. Some natural materials, such as cork, can freeze in winter, limiting year-round play. Phasing out crumb rubber also raises questions about how to manage the millions of tires currently recycled into turf production.
Tire pollution under growing scrutiny The findings arrive as governments increase scrutiny of tire-derived pollution. The European Union has already banned the sale of crumb rubber under broader microplastics regulations, setting a phaseout in motion.
“Our research shows a clear need to address contaminant release from turf fields,” said Dr. Scholes. “These data can help guide decisions on field design and stormwater treatment to protect aquatic ecosystems.”
The research was supported by the BC Salmon Restoration and Innovation Fund.
Interview language(s): English (Moloney, Scholes)
END
Researchers traced the pollution to crumb rubber infill made from recycled tires, a material widely used on synthetic turf fields. The team found it consistently released 6PPD-quinone and other contaminants across fields of different ages.
“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—frequently without treatment.”
The project began after streamkeepers in North Vancouver contacted the researchers in late 2023, reporting that crumb rubber was washing off a nearby turf field. Dead coho had also been found in an adjacent stream.
“We already knew this chemical washes off tire debris on roads and can kill salmon,” Moloney said. “It made sense to ask whether fields using the same material might be doing something similar.”
Supervised by civil engineering assistant professor Dr. Rachel Scholes, the team collected infill samples from 12 turf fields—nine containing crumb rubber and three using alternative materials—and analyzed which chemicals leached into water. They also collected drainage during three rainstorms from an operating field.
Toxic releases throughout a field’s life Drainage from one monitored field showed 6PPD-quinone concentrations exceeding levels lethal to juvenile coho salmon, even though the field’s infill was more than six years old. While runoff is often diluted before reaching streams, researchers say the greatest risk is likely in smaller watersheds or where multiple fields drain into the same outfall.
Tests also identified numerous compounds not listed in regulatory inventories of tire ingredients, possibly due to chemicals transferred by field users and weather-driven changes in the rubber over time. Heavy metals such as zinc and copper—both harmful to aquatic life—were detected consistently.
“Every time it rains, these fields release a mix of chemicals into the drainage system,” Moloney said. “That needs to be taken seriously.”
Potential treatments and trade-offs Because turf fields drain through fixed pipe networks, the researchers say stormwater treatment is feasible. A 2023 study from the same UBC group showed that passing stormwater through a planted soil filter can reduce 6PPD-quinone concentrations by roughly 10-fold.
The team also found that non-rubber infills released fewer contaminants, but tend to be more expensive. Some natural materials, such as cork, can freeze in winter, limiting year-round play. Phasing out crumb rubber also raises questions about how to manage the millions of tires currently recycled into turf production.
Tire pollution under growing scrutiny The findings arrive as governments increase scrutiny of tire-derived pollution. The European Union has already banned the sale of crumb rubber under broader microplastics regulations, setting a phaseout in motion.
“Our research shows a clear need to address contaminant release from turf fields,” said Dr. Scholes. “These data can help guide decisions on field design and stormwater treatment to protect aquatic ecosystems.”
The research was supported by the BC Salmon Restoration and Innovation Fund.
Interview language(s): English (Moloney, Scholes)
END