A new study from the University of British Columbia has found that artificial turf fields across Metro Vancouver are releasing 6PPD-quinone — a transformation product of a tire protectant known to be toxic to coho salmon — into municipal stormwater systems, with contamination persisting years after installation.
The research traced the pollution to crumb rubber infill made from recycled tires, a material commonly used in synthetic fields. According to the study, the infill consistently released 6PPD-quinone and other contaminants regardless of the field’s age.
“An average turf field contains about 125 tonnes of crumb rubber, roughly 20,000 tires,” said Katie Moloney, a PhD student 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.”
Artificial turf fields were introduced in the 1960s as resilient and low-maintenance sports surfaces, resulting in more than 19,000 artificial turf fields in the U.S. alone, the study says. There are approximately 600 to 750 new installations there annually.
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The UBC project began in late 2023 after streamkeepers in North Vancouver reported crumb rubber washing off a nearby turf field, alongside dead coho salmon in a neighbouring 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.”
Led by civil engineering assistant professor Rachel Scholes, the research team collected infill samples from 12 turf fields — nine containing crumb rubber and three using alternative materials — and analyzed the chemicals leaching into water. Drainage samples were also collected during three rainstorms from an active field.
Contamination persists over time
The study found that drainage from one monitored field contained 6PPD-quinone concentrations exceeding levels lethal to juvenile coho salmon, even though the infill was more than six years old. While runoff is often diluted before reaching streams, researchers noted the risk may be higher in smaller watersheds or where multiple fields drain into the same outlet.
In addition to 6PPD-quinone, testing revealed numerous other compounds not listed in regulatory inventories of tire ingredients, as well as heavy metals such as zinc and copper — both known to harm aquatic life.
“Every time it rains, these fields release a mix of chemicals into the drainage system,” Moloney said. “That needs to be taken seriously.”
Treatment options and trade-offs
Because artificial turf fields drain through fixed pipe systems, the researchers say stormwater treatment is a viable mitigation option. A 2023 study by the same UBC team found that passing runoff through a planted soil filter can reduce 6PPD-quinone concentrations by roughly tenfold.
The study also found that alternative infill materials released fewer contaminants, though they tend to be more expensive. Some natural options, such as cork, may freeze in colder conditions, limiting year-round use. Phasing out crumb rubber also raises questions about managing the large volume of recycled tires currently used in artificial turf production.
Growing regulatory scrutiny
The findings come as regulators increase scrutiny of tire-derived pollution. The European Union has already moved to ban the sale of crumb rubber under broader microplastics regulations, initiating a phaseout.
In San Francisco, a ruling is also expected in the near future on a lawsuit filed by environmental groups representing fishing organizations against major tire manufacturers, including Bridgestone, Michelin and Goodyear. They argue that the companies are violating the Endangered Species Act by allowing the chemical to enter waterways through stormwater runoff.
In 2024, Environment and Climate Change Canada added 6PPD as a priority for assessment, the department’s minister told a group of environmental advocacy organizations lobbying for federal action on the chemical.
“Our research shows a clear need to address contaminant release from turf fields,” Scholes said. “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.
