Every time rain falls on synthetic sports fields across the Pacific Northwest, a deadly chemical cocktail washes into storm drains—and ultimately into streams where juvenile coho salmon face lethal exposure to tire-derived toxins.
A new study from University of British Columbia researchers reveals that crumb rubber infill—recycled tire material used on artificial turf—releases 6PPD-quinone, a compound toxic to coho salmon at concentrations routinely detected in field drainage. The findings, published this week, expose a hidden conflict between recreational infrastructure and species survival.
"Every time it rains, these fields release a mix of chemicals into the drainage system," explained researcher Katie Moloney. The team monitored drainage from an aging field in Metro Vancouver and found 6PPD-quinone persisting at lethal thresholds six years after installation—alongside heavy metals like zinc and copper, plus numerous unregulated compounds.
An average field contains approximately 125 tonnes of crumb rubber from some 20,000 tires. Across the region's hundreds of synthetic fields, that translates to millions of tires' worth of chemical exposure washing into watersheds with every storm.
For coho salmon—already stressed by climate change, habitat loss, and overfishing—this represents yet another pressure on populations clinging to survival. Pacific salmon face warming streams that reduce oxygen availability, urbanization that fragments spawning habitat, and now toxic runoff from the very fields where communities gather for recreation.
The study tested 12 fields across Metro Vancouver, finding rubber-infill fields consistently released contaminants. Alternative infill materials reduced chemical leaching but carry higher costs and may not perform year-round in cold climates—creating a tension between environmental protection and accessibility.
Planted soil filters can reduce 6PPD-quinone levels by approximately tenfold, the researchers found, but such stormwater treatment infrastructure requires investment many communities have not prioritized. The has already banned crumb rubber sales under microplastics regulations, establishing a phaseout trajectory absent in .
