Population Health

January 19, 2021

Tire chemical responsible for killing coho salmon in urban streams

Image of a student holding a sampling pole that is used to collect creek waterA team led by researchers at the University of Washington Tacoma, UW and Washington State University Puyallup have discovered why more than half of the coho salmon that return to Puget Sound’s urban streams die before they can spawn.

When it rains, stormwater flushes bits of aging vehicle tires on roads into neighboring streams. The killer is in the mix of chemicals that leach from tire wear particles: a molecule related to a preservative that keeps tires from breaking down too quickly.

Now that the chemical has been identified as the “smoking gun” behind coho death in freshwater streams, the team can start to understand why this chemical is so toxic and, ultimately, how to protect the salmon.

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