EVERETT — Washington will be the first state to set a numeric, freshwater limit for 6PPD-quinone — a chemical that helps tires last longer and is known to kill coho salmon before they spawn.
Last week, the state Department of Ecology established new limits for over 20 other toxic chemicals, in addition to 6PPD, to protect aquatic life in marine and fresh waters.
“This is really the first step in the right direction,” said Bryson Finch, a toxicologist for Ecology’s water quality program. “It was an opportune time to review the science.”
Ecology’s new limit for 6PPD-quinone is set at 0.012 micrograms per liter. The new standards will officially become effective in Washington on Sept. 14, though the U.S. Environmental Protection Agency has to conduct a separate approval process.
When 6PPD reacts with ozone in the air, it becomes 6PPD-quinone.
In 2021, researchers found coho salmon die after only a few hours of exposure to the chemical — devastating a critical resource for local tribes and food staple for orcas, sea lions and seals.
Scientists are still determining why coho salmon, versus other species, are more vulnerable to 6PPD.
The chemical often flows off of roads and into waterways when it rains.
New stormwater facilities, like one planned for Mountlake Terrace, will filter out 6PPD from runoff.
The intent of the state limit for 6PPD is to “identify what level that’s been harmful,” said Melissa Gildersleeve, section manager for Ecology’s water quality program. “Then we would make cleanup plans,” she said.
Salmon also become exposed to 6PPD when locals abandon tires in nearby streams.
Snohomish resident Doug Ewing and a crew of volunteers have removed 69 tires from the Snohomish River over the past four weeks — motivated by the knowledge that 6PPD is deadly to fish.
Ewing regularly hunts for garbage at Thomas’ Eddy across from the Bob Heirman Wildlife Park, though he often struggles to wrestle tires out of the water and lug them to shore.
This summer, a group of young locals have helped Ewing load his canoe with tires, haul them up the steep river bank and stack them in his pickup truck. From there, Ewing drops them off at Les Schwab Tires, where they get recycled.
The state Department of Ecology continues to research how 6PPD-quinone harms wildlife and what organizations can do to mitigate the chemical.
Ta’Leah Van Sistine: 425-339-3460; taleah.vansistine@heraldnet.com; Twitter: @TaLeahRoseV.
Talk to us
> Give us your news tips.
> Send us a letter to the editor.
> More Herald contact information.
