Puget Sound salmon deaths traced to tires, not climate change.

 Urban streams in the Puget Sound and Seattle area have Coho salmon mortalities of 50% before reaching spawning areas, notably after big rainfalls.  The easy villain was "climate change".  The surprise villain is leached tire preservative combined with ozone in urban stormwater runoff.  This was confirmed in the Los Angeles and San Francisco area too.  See University of Washington report (hat tip Alan Watts)

Picture at WU story

The detective work reported is fascinating leading to an unsuspected chemical whose general formula they figured from the salmon deaths but whose source they initially knew nothing about.

6PPD is added to extend tire life. Particles worn away from tires have a byproduct of 6PPD-quinone after reacting with ozone.  The chemical signature with 18C 22H 2N and 2O matched.

The most economical and recommended fix is to look for other tire preservatives.  Treating storm water at that level is impractical.