Scientists at the San Francisco Estuary Institute (SFEI) have found a highly toxic tire-related contaminant at levels lethal to coho salmon in stormwater flowing through four sites in the Bay Area. The contaminant, derived from a tire preservative, has been discovered by Washington state researchers to be responsible for high levels of coho salmon deaths in Puget Sound streams. These findings will  inform a petition by state stormwater leaders to the Department of Toxic Substances Control to address pollution of California streams caused by tires.

The research team, led by scientists at the University of Washington and Washington State University, published the results of their investigation yesterday in the journal Science. The chemical, 6PPD-quinone (pronounced "kwih-known"), can wash into streams along with tire wear particles when it rains. Scientists at San Francisco Estuary Institute collected samples from nine Bay Area streams and storm drains during storm events; four contained levels of this contaminant above the concentration at which half the coho salmon die after a few hours of exposure in laboratory experiments. SFEI’s Alicia Gilbreath and Rebecca Sutton are co-authors on the study.