USGS Research on 6PPD-quinone: Where the Rubber Meets the Road
Stormwater and road runoff are recognized forms of pollution that can contain chemicals harmful to fish and other aquatic animals. This includes 6PPD-quinone, the oxidized form of the chemical compound 6PPD that is used to prevent tires from degrading and cracking, ensuring driver safety. As 6PPD-quinone sheds from tires during normal wear it can enter streams in stormwater runoff.
6PPD-quinone
6PPD-quinone is one of the most toxic chemicals to aquatic animal life. In 2020, researchers at Washington State University identified 6PPD-quinone as the chemical responsible for urban runoff mortality syndrome observed in coho salmon in the Pacific Northwest. 6PPD-quinone is acutely toxic to coho salmon, with high mortality at low concentrations. 6PPD-quinone is also acutely toxic to brook trout, rainbow/steelhead trout, lake trout, and white-spotted char but at higher concentrations and with lower mortality. Many questions remain regarding 6PPD-quinone toxicity including chronic (or sublethal) impacts on fish health, effects on other aquatic and terrestrial organisms, and whether human health is adversely affected.
Current Research
The U.S. Geological Survey (USGS) has a diverse array of analytical, laboratory, modeling, and field capabilities which makes us uniquely positioned to study 6PPD-quinone. Current efforts examine the occurrence, fate and transport, exposure pathways, bio-uptake, and effects of 6PPD-quinone on aquatic and terrestrial communities. Additionally, USGS scientists have developed methods to test the environmental safety of alternative tire additives. Our partners include Federal, State, and Tribal agencies, as well as the tire industry to find a solution to the issue. Examples of USGS research include:
Research Topics
- Developing an analytical method for measuring 6PPD-quinone stability, persistence, and accumulation in biotic and abiotic media.
- Advancing toxicity screening methods to assess the effects of 6PPD-quinone and chemical alternatives.
- Determining the chronic and acute toxicity of 6PPD and 6PPD-quinone.
- Addressing whether 6PPD-quinone affects host fish immunity against microbial pathogens.
- Helping evaluate stormwater impacts on juvenile coho salmon in urban Seattle.
- Deploying passive sampling devices in streams to monitor 6PPD-quinone exposure over time to assess accumulative exposure risks for young salmon.
- Creating a national “hot spot” map of areas and vulnerable fish species that may be most greatly affected by 6PPD-quinone in storm and road runoff.
- Conducting stormwater and stormwater management studies to evaluate water quality, and quantity, and assess management practices to reduce contaminant transport.
Science Needs and Data Gaps
Addressing remaining science needs and knowledge gaps related to 6PPD-quinone will help managers make informed decisions. The scope of USGS expertise allows us to develop integrated science to address stormwater runoff mitigation, identify suitable alternatives, assess toxicity, understand the movement through the environment, and further understand the effects on fish and wildlife. The next steps in answering these needs include research on:
Future Direction
·Sampling Protocols and Analytical Methods – Develop standardized sampling protocols and analytical methods for water, soil, tissue, and plasma.
·Environmental Sources and Source Apportionment – Develop models and identify data for quantifying or assessing source contributions of 6PPD-quinone to watersheds due to stormwater runoff and other potential sources.
·Environmental Occurrence – The primary focus has been the Pacific Northwest where mortality in Coho salmon has been documented. Additional research must be conducted to determine if there are similar risk posed to other species across the nation.
·Environmental Fate and Transport – Obtain a better understanding of 6PPD and 6PPD-quinone sources, movement through the environment, persistence, and exposure pathways in water, atmosphere, sediments, and biota.
·Human and Wildlife Routes of Exposure – Research is currently limited to salmonid species. Data is lacking on the effects of direct exposure to 6PPD-quinone on aquatic invertebrates, and freshwater fish, as well as indirect exposure at higher trophic levels such as in wildlife and humans.
·Bioaccumulation and Biomagnification – Determine if 6PPD-quinone accumulates and concentrates in freshwater fish and how (e.g., direct exposure, consumption of exposed food sources).
·Ecotoxicology – Further advance organism and cell-line toxicity screening methods that have been established by the USGS. This includes expanding methods to other species, testing for acute and chronic toxicity, and incorporating the mechanisms of toxicity, such as changes in gene expression through transcriptomics.
USGS scientists will continue to advance our understanding of 6PPD-quinone to inform resource managers, work closely with partners (State, Federal, Tribal, and private industry) to identify safer alternatives to 6PPD-quinone and evaluate different road runoff management solutions that can capture 6PPD-quinone before it enters the watershed.
Stormwater and road runoff are recognized forms of pollution that can contain chemicals harmful to fish and other aquatic animals. This includes 6PPD-quinone, the oxidized form of the chemical compound 6PPD that is used to prevent tires from degrading and cracking, ensuring driver safety. As 6PPD-quinone sheds from tires during normal wear it can enter streams in stormwater runoff.
6PPD-quinone
6PPD-quinone is one of the most toxic chemicals to aquatic animal life. In 2020, researchers at Washington State University identified 6PPD-quinone as the chemical responsible for urban runoff mortality syndrome observed in coho salmon in the Pacific Northwest. 6PPD-quinone is acutely toxic to coho salmon, with high mortality at low concentrations. 6PPD-quinone is also acutely toxic to brook trout, rainbow/steelhead trout, lake trout, and white-spotted char but at higher concentrations and with lower mortality. Many questions remain regarding 6PPD-quinone toxicity including chronic (or sublethal) impacts on fish health, effects on other aquatic and terrestrial organisms, and whether human health is adversely affected.
Current Research
The U.S. Geological Survey (USGS) has a diverse array of analytical, laboratory, modeling, and field capabilities which makes us uniquely positioned to study 6PPD-quinone. Current efforts examine the occurrence, fate and transport, exposure pathways, bio-uptake, and effects of 6PPD-quinone on aquatic and terrestrial communities. Additionally, USGS scientists have developed methods to test the environmental safety of alternative tire additives. Our partners include Federal, State, and Tribal agencies, as well as the tire industry to find a solution to the issue. Examples of USGS research include:
Research Topics
- Developing an analytical method for measuring 6PPD-quinone stability, persistence, and accumulation in biotic and abiotic media.
- Advancing toxicity screening methods to assess the effects of 6PPD-quinone and chemical alternatives.
- Determining the chronic and acute toxicity of 6PPD and 6PPD-quinone.
- Addressing whether 6PPD-quinone affects host fish immunity against microbial pathogens.
- Helping evaluate stormwater impacts on juvenile coho salmon in urban Seattle.
- Deploying passive sampling devices in streams to monitor 6PPD-quinone exposure over time to assess accumulative exposure risks for young salmon.
- Creating a national “hot spot” map of areas and vulnerable fish species that may be most greatly affected by 6PPD-quinone in storm and road runoff.
- Conducting stormwater and stormwater management studies to evaluate water quality, and quantity, and assess management practices to reduce contaminant transport.
Science Needs and Data Gaps
Addressing remaining science needs and knowledge gaps related to 6PPD-quinone will help managers make informed decisions. The scope of USGS expertise allows us to develop integrated science to address stormwater runoff mitigation, identify suitable alternatives, assess toxicity, understand the movement through the environment, and further understand the effects on fish and wildlife. The next steps in answering these needs include research on:
Future Direction
·Sampling Protocols and Analytical Methods – Develop standardized sampling protocols and analytical methods for water, soil, tissue, and plasma.
·Environmental Sources and Source Apportionment – Develop models and identify data for quantifying or assessing source contributions of 6PPD-quinone to watersheds due to stormwater runoff and other potential sources.
·Environmental Occurrence – The primary focus has been the Pacific Northwest where mortality in Coho salmon has been documented. Additional research must be conducted to determine if there are similar risk posed to other species across the nation.
·Environmental Fate and Transport – Obtain a better understanding of 6PPD and 6PPD-quinone sources, movement through the environment, persistence, and exposure pathways in water, atmosphere, sediments, and biota.
·Human and Wildlife Routes of Exposure – Research is currently limited to salmonid species. Data is lacking on the effects of direct exposure to 6PPD-quinone on aquatic invertebrates, and freshwater fish, as well as indirect exposure at higher trophic levels such as in wildlife and humans.
·Bioaccumulation and Biomagnification – Determine if 6PPD-quinone accumulates and concentrates in freshwater fish and how (e.g., direct exposure, consumption of exposed food sources).
·Ecotoxicology – Further advance organism and cell-line toxicity screening methods that have been established by the USGS. This includes expanding methods to other species, testing for acute and chronic toxicity, and incorporating the mechanisms of toxicity, such as changes in gene expression through transcriptomics.
USGS scientists will continue to advance our understanding of 6PPD-quinone to inform resource managers, work closely with partners (State, Federal, Tribal, and private industry) to identify safer alternatives to 6PPD-quinone and evaluate different road runoff management solutions that can capture 6PPD-quinone before it enters the watershed.