6PPD-Quinone Active

For 25 years, Coho Salmon (Oncorhynchus kisutch) deaths during fall spawning in the Pacific Northwest United States were contributed to a phenomenon known as Urban Runoff Mortality Syndrome (URMS), a term acknowledging stormwater and road runoff as the likely cause for these mass die-offs. 

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In 2021 a singular chemical present in urban runoff was found to kill juvenile coho salmon at levels found in the environment. The chemical in question is 6PPD-quinone (6PPD-Q), a form of the chemical compound 6PPD which is used to prevent tires from degrading and cracking, ensuring driver safety. 6PPD-Q is created when 6PPD is exposed to ozone in the air.  

6PPD-Q is released from tires through normal wear. Once on the roads and in the atmosphere, it can enter streams through dust transport, rain, and storm runoff where fish and other organisms can be exposed. Coho salmon are particularly sensitive to exposure to 6PPD-Q, and current research is showing other fish like brook trout and rainbow trout are also affected. It has been characterized as the second most toxic chemical for aquatic animal life, and has been detected in human urine, raising concerns for human health. 

There remain many questions about 6PPD-Q that need to be answered to understand its effects on the environment, wildlife, and people - including how it moves throughout the environment, at what levels is it found in water and sediment, how animals and people are exposed, effects of exposure, and how long 6PPD-Q lasts in these various locations.  

How is USGS helping?

The U.S. Geological Survey (USGS) is studying 6PPD-Q and, through the Environmental Health Program's Integrated Science Teams and multiple Water Science Centers, has a wide range of capabilities uniquely positioned to study the movement, fate, and effects of 6PPD-Q in the environment.

• USGS is collaborating with the US EPA Office of Water to conduct high quality acute (short-term) toxicity studies for salmon species and other aquatic organisms that can be used to support the development of national water quality criteria for 6PPD-Q. Other toxicity questions USGS is addressing include: 
  • What, where, and how widespread are impacts are there to juvenile coho salmon in urban Seattle?
  • Does exposure to 6PPD-Q cause other, non-lethal effects to salmon, such as impacting their ability to resist diseases, or affecting their metabolism?
  • Does 6PPD-Q continue to be toxic over time after being introduced to streams?
  • Similar to 6PPD-Q, are other 6PPD products present in the environment, and what are their effects? 
• USGS Scientists are developing methods to understand movement, transport, and fate of 6PPD-Q, as well as uptake by aquatic organisms to develop effective treatment methods.
  • As part of this, analytical methods to understand 6PPD-Q stability, persistence, and accumulation in sediments and in organisms (bioaccumulation in individuals, and biomagnification up food webs) are being developed. 
• USGS scientists have developed methods to test the safety of alternative tire additives. 
  • USGS is working with international, Federal, State, and Tribal agencies, as well as the tire manufacturing industry to find chemical alternatives that are safer for the environment and still support long-lasting tires and safe driving.
• USGS Scientists are utilizing national transportation (traffic density) and road data (road-stream crossings, road density, and road type) along with known and potential fish occurrence and habitats at multiple scales to estimate 6PPD-Q 'hot spots' where sensitive fish species may be affected. 

Learn more about the USGS Science Centers working on 6PPD-Q.

• Western Fisheries Research Center | U.S. Geological Survey (usgs.gov)
• Columbia Environmental Research Center | U.S. Geological Survey (usgs.gov)
• Kansas Water Science Center | U.S. Geological Survey (usgs.gov)
• Washington Water Science Center | U.S. Geological Survey (usgs.gov)
• California Water Science Center | U.S. Geological Survey (usgs.gov)

External Resources 

• US Environmental Protection Agency 6PPD-Q  
• 6PPD - Washington State Department of Ecology
• Tire Anti-Degradants (6PPD) - ITRC 

† Hypertext links to non-USGS products and services; and the use of trade names, trademarks, company names, or other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty by the U.S. Geological Survey (USGS), U.S. Department of the Interior, or U.S. Government.