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Salmon-killing toxin: Scientists share new discoveries, need for action in Congressional roundtable

Part of a team that discovered a toxic chemical that kills salmon in urban streams before they can spawn, UW associate professor Edward Kolodziej, WSU assistant professor Jenifer McIntyre, and Zhenyu Tian a research scientist at the Center for Urban Waters, visit Longfellow Creek near Seattle (Mark Stone/University of Washington).

Washington State University stormwater researchers Jen McIntyre and John Stark shared perspectives on research to save salmon in a Feb. 25 virtual roundtable hosted by U.S. Representatives Marilyn Strickland and Derek Kilmer.

McIntyre, an associate professor in the School of the Environment, and Stark, director of the Washington Stormwater Center, joined participants from the Washington State Department of Ecology, University of Washington, Northwest Fisheries Science Center, the Nisqually Indian Tribe, and the U.S. Tire Manufacturers Association to discuss near- and long-term ways to address a salmon-killing chemical in urban runoff.

In 2020, scientists from UW and WSU found that a chemical—a tire preservative called 6PPD-quinone—runs off roads and into streams, ultimately disrupting the blood-brain barrier in salmon.

Jenifer McIntyre“We’ve discovered that 6PPD-quinone is even more toxic than we’d initially reported—almost 10 times more toxic,” McIntyre said.

Working with labs in North America, Asia and Europe, scientists measured the chemical in surface waters at concentrations of concern “basically everywhere that it’s been looked for,” McIntyre added. “It’s found in air pollution, urban soils, and urban dust. It’s ubiquitous.”

Funded by the Washington State Department of Ecology, WSU scientists are working to understand environmental conditions as well as life stages of coho that affect toxicity. They have begun to look for the chemical’s effects in other species.

Stark and McIntyre urged support for research, including establishment of a regional stormwater center of excellence that builds on WSU’s decades-long efforts to understand salmon mortality.

Formal portrait of John Stark
John Stark

“We built the largest stormwater research center in the country,” Stark said. At Puyalllup, WSU scientists lead rain garden and permeable pavement experiments in search of solutions to remove pollutants.

“We’re poised to be able to address nearly all the critical data gaps,” McIntyre said. “In the past year, we’ve been doing what we can to move forward our knowledge with minimal resources.”

While it could take years, if not longer, to phase out this particular toxin, tires being sold today will pollute for decades, Stark said.

“We need to find other ways to get rid of those chemicals in a safe, effective, and economic manner,” he said.