Two Washington State universities have completed detailed research into the mass death of coho salmon. The causes have been unexplained until a previously unknown compound, 6PPD-quinone, was detected in river water samples taken in the spawning grounds of the salmon.

6PPD is an additive used in rubber tyre manufacture to prevent degradation by ozone. However over time ozone interacts with this additive causing the release of tiny concentrations of 6PPD-quinone.

While the precise action of the compound on the fish is not known, research suggests that the compound has causes acute cardio-respiratory damage.

As an emerging contaminant it is not known how widespread the problem is – it could impact on how we make, use and dispose of tyres.

Is this a pollutant that affects just one species in one location or could this be the latest PFAS?