Tracking Tire Chemicals in Oregon Streams

6PPD is a chemical additive that keeps tires from cracking and degrading. This helps tires stay safe and durable. However, when 6PPD reacts with the atmosphere it forms a new compound called 6PPD-quinone. Tire wear releases particles and chemicals, including 6PPD-quinone (6PPD-Q), onto roads. Rain and stormwater wash these materials into streams and nearby ecosystems. 

In urban watersheds, scientists have linked salmon deaths to toxic stormwater runoff. Research shows that 6PPD-q levels in runoff can exceed lethal thresholds for Coho Salmon (Oncorhynchus kisutch), making its role in salmon declines a major focus of ongoing studies. 

What We’re Studying at Oregon Water Science Center:

Monitoring Streams: 

We collect water and sediment samples from urban streams and highways to measure 6PPD-Q levels during storms and dry periods.

Testing New Tools: 

We’re exploring innovative methods like fluorescence sensors to predict 6PPD-Q levels in real time, which could make monitoring faster and more cost-effective.

Looking at Proxies: 

In addition to fluorescence, metals like zinc and copper, which also come from tires and brakes, may help us estimate 6PPD-Q levels without expensive lab tests.

Modeling: 

We’re using advanced modeling tools to understand how 6PPD-Q moves through watersheds and how green infrastructure can reduce its impact.   

Why It Matters: 

6PPD-Q has been linked to Coho Salmon deaths in the Pacific Northwest. Understanding where and when this compound appears helps agencies and communities take action to protect fish and improve water quality.