December 4, 2020 — A highly toxic chemical used in the production of millions of tires every year is killing salmon in the Pacific Northwest, and it is being detected in streams across Northern California, a new study finds.
Scientists have known for decades that stormwater runoff from roads, highways and other urban areas has been linked to high rates of coho salmon deaths in Washington state, where as many as 90% of salmon in the Puget Sound area have died before they could spawn.
The new study published in the research journal Science on Thursday has identified a culprit chemical for the first time — a commonly used preservative called 6PPD used to give tires longer life.
“I think the broader impact is as we have already found this in San Francisco (Bay) creek water as well as the road runoff,” said the study’s lead author, Zhenyu Tian, a researcher at the University of Washington Tacoma. “We believe this thing is a prevalent contaminant. Wherever you have a busy highway, you have runoff from there and you probably will detect it. Our detection rate for this chemical in runoff is almost always 100%. For coho salmon, it’s definitely a threat.”