Salmon & Legacy Debris
The Salmon & Legacy Debris project provides resources and support to address decades of large debris pollution and contamination in our local streams and waterways.
Next SectionImpact
December 2025
15,505 pounds
Total waste removed
141 tires
Tires removed
“Legacy debris reminds us of a time when we treated our rivers like dumping grounds. Now, we have an opportunity to remedy that relationship by cleaning up the river and protecting it for generations to come.”
Anna Bachmann, Salmon & Legacy Debris project manager
Thriving Rivers and Communities vs. Marine Debris
Trash, garbage, junk—whatever you call it, marine debris is a major problem affecting our shorelines and waterways. Debris includes things like appliances, tires, fishing gear, and construction waste.
Once debris enters our waterways, it usually breaks into smaller pieces and keeps moving around. Some of this debris, which we call legacy debris, has been in our water for a long time.
Toxic Legacy
Legacy debris is not only ugly to look at, it’s also often full of toxic materials that can affect our health or the health of species we rely upon, like salmon.
Legacy debris results from decades of dumping and industrial activity that happened when environmental laws were not as strong as they are today. The people who dumped this debris are long gone, and no one has taken responsibility for the damage it continues to cause.
Where do we find debris?
Explore a map of Seattle’s Duwamish River to learn more about legacy debris in the area.
Debris dumping isn’t just in the past!
Unpermitted industrial activity and illegal disposal continue to negatively impact the Green-Duwamish River and other waterways to this day. Legacy debris removal is just one piece of the cleanup puzzle, but you can help!
All About Tires
Tires are a great example of legacy debris that leaks toxic materials into the Green-Duwamish River.
Did you know that car tires contain a chemical called 6PPD? It’s used to preserve rubber in car tires, so they don’t break down as quickly. This chemical is present in all tires (yes, all of them!) and some other rubber products, like footwear, synthetic turf, and playground surfaces. 6PPD creates a different, harmful chemical called 6PPD-Q when it reacts with air and sunlight.
6PPD-Q is present in tire dust on streets and parking lots. When it rains, stormwater washes over paved surfaces and carries it into our streams and rivers. Unfortunately, 6PPD-Q is extremely toxic to aquatic organisms.
Solving A Salmon Mystery
Scientists in Washington proved that 6PPD-Q is lethal to coho salmon. Researchers spent years studying why stormwater in cities harms certain types of salmon. They discovered a direct link between 6PPD-Q and the death of coho salmon during their spawning journey. Later studies also determined that 6PPD-Q is toxic to chinook, steelhead, and rainbow trout. This means that salmon using urban creeks and streams are at a higher risk for potential 6PPD-Q exposure, with deadly consequences.
Public Space & Urban Rivers
King County’s Duwamish River basin is full of tires. They’re on cars, used as boat and dock bumpers, and embedded in the shoreline as bulkheads. Sometimes, they’re simply dumped into the river or abandoned on surrounding public and private lands.
We know tire chemicals are lethally toxic to coho salmon, but they can also harm people. Tires contain Polycyclic Aromatic Hydrocarbons (PAHs), Heavy Metals, Phthalates, and more, all of which can cause environmental and public health concerns. Our neighborhoods and ecosystems should be healthy places to live, and our public spaces should be free of toxic pollution. We can start removing legacy debris today, for a more resilient future.