From Tread to Watershed: How Tire Wear Particle Chemicals 6PPD and 6PPD-quinone Are Impacting Waterways
Tire and road wear particles (TRWPs) are generated during normal driving conditions and contain both rubber and roadway materials. These particles travel from the roadways and urban environments into surrounding ecosystems where there are deleterious impacts from both the TRWPs and leached rubber chemicals. Recent studies have demonstrated the widespread occurrence and toxicity of TRWPs and their associated chemicals (e.g. 6PPD, 6PPD-quinone, benzothiazoles, phthalate esters, polycyclic aromatic hydrocarbons, etc.) in both aquatic and terrestrial environments. The Kansas Water Science Center's (KS WSC) Organic Geochemistry Research Laboratory (OGRL) is conducting research to further understand the ecological impacts of these ubiquitous anthropogenic materials which necessitates an interdisciplinary approach to address the many knowledge gaps relating to the sources, transport, fate, toxicity, and reduction strategies of TRWPs and their associated chemicals.
6PPD-quinone is a transformation product of 6PPD, an antiozonant used in tires.
Currently, 6PPD is used in all tires and can contaminate stormwater anywhere tires are used.
The rubber-derived ozone transformation product 6PPD-quinone (6PPDQ) was discovered in 2020 as a causative agent for urban runoff mortality syndrome in coho salmon. Tire and road wear particles are mobilized during urban storm events and transport 6PPD-quinone into surrounding aquatic ecosystems with concentrations that exceed acute toxicity thresholds for several salmonid species and the Environmental Protection Agency’s (EPA) aquatic life screening values of 11ng/L. These urban runoff events create sampling challenges and storm chasing to capture and characterize the transient exposure.
The widespread use of rubber in products such as tires and the documented harmful environmental effects necessitates an improved understanding of the occurrence, fate, and bioavailability of 6PPD-quinone.
Highlighted Science
After the discovery of the tire antiozonant transformation product 6PPD-quinone in 2020, research into rubber antiozonants chemicals began in earnest. The KS WSC OGRL developed a method for the analysis of 6PPD and 6PPD-quinone in water in 2021 to support toxicological studies and understand the environmental prevalence, fate, and bioavailability. The analytical method was published in 2024 to inform sampling procedures and hold times and advance understanding of stream exposures. Results from a nationwide reconnaissance of 6PPD and 6PPD-quinone in surface waters from 94 sites with varying land-use (urban, agricultural, and forested) and streamflow found that storm events mobilize 6PPD-quinone primarily from urban watersheds; downstream concentrations exceeded EPAs recently released 6PPD-quinone 11 ng/L freshwater acute aquatic life screening value for the protection of aquatic life. https://doi.org/10.1016/j.chemosphere.2024.142830
- With a short half-life, 6PPD has a low aqueous detection frequency
- Urban-impacted stormwater has the highest observed aqueous concentrations of 6PPD-quinone
- 6PPD-quinone stream exposures are transient pulse(s) at concentrations toxic to coho salmon.
- Sampling protocols and monitoring should account for the episodic nature of exposure.
In FY25 research is continuing at the KS WSC OGRL to advance knowledge about the ecosystem occurrence, partitioning, and fate of 6PPD and 6PPD-quinone:
- Ecological Implications of 6PPD/6PPD-quinone Partitioning: Occurrence of 6PPD and 6PPD-quinone in suspended and bed sediments
- Passive Sampling: Use of diffusive gradients in thin film (DGT) passive samplers for 6PPD-quinone
- Bioavailability (Occurrence Sampling): collaborative studies across the USGS to determine 6PPD and 6PPD-quinone levels in ecologically relevant habitats
- Toxicology Studies: collaborations with USGS Western Fisheries Research Center and Columbia Environmental Research Center exploring facets of 6PPD and 6PPD-quinone toxicity
- Method Validation: Participation in an inter-laboratory validation study and seeking accreditation with Washington State Department of Ecology
6PPD
- N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine
- Tire antiozonant that prevents rubber breakdown
- Ozone in the atmosphere interacts with tires
6PPD-quinone
- 6PPD and ozone reaction protects the tire, but also produces 6PPD-quinone (6PPDQ)
Current Analytical Capabilities
Methods for 6PPD-quinone and 6PPD
Analysis Code: LCTR
Direct Inject Water Method
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Water
Reporting Limit: 0.002 µg/L
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Analysis Code: LCTR-EPA
EPA Draft Method 1634
Instrumentation: liquid chromatography/tandem mass spectrometry
Matrix: Water (predominantly stormwater and surface water)
Reporting Limit: 2.00 ng/L
Compound/CAS#:
6PPD-quinone / 2754428-18-5
In Development
Analysis Code: LCTW
Whole Water (Aqueous and Suspended Material) Method
Sample Prep: Energized Dispersive Guided Extraction and Solid-phase extraction
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Stormwater or Turbid Waters
Reporting Limit: in development
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Analysis Code: LCTS
Solid Method
Sample Prep: Energized Dispersive Guided Extraction and Solid-phase extraction
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Sediments and Soils
Reporting Limit: in development
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Contact Rachael Lane (785-760-4540; rflane@usgs.gov) for details about bottles or additional tire wear compounds of interest
Highlighted Outreach
- ITRC Tire Anti-Degradants (6PPD) Guidance Document (publication Fall 2025) Tire Anti-Degradants (6PPD) - ITRC (itrcweb.org)†
- Lane, R.F. subgroup co-lead for Environmental Assessments Strategies chapters
- Lane R.F. subgroup co-lead Training and Outreach material for 6PPD and 6PPD-quinone
- Lane, R.F. (Presenter, Invited) 2023. Analytical Capabilities for 6PPD. ITRC Tire Anti-Degradants (6PPD) Monthly Meeting
- Lane, R.F. 2025. ITRC 6PPD CLU-IN Trainer
-
Lane, R.F (Presenter, Invited), Kolpin, D.W.; Bradley, P.M., Smalling, K.L. 2023. Understanding the environmental occurrence and fate of the tire leachate transformation product 6PPD-Quinone. USGS CMWSC Seminar Series
† 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.
6PPD-quinone
6PPD Research at Columbia Environmental Research Center
Tire and road wear particles (TRWPs) are generated during normal driving conditions and contain both rubber and roadway materials. These particles travel from the roadways and urban environments into surrounding ecosystems where there are deleterious impacts from both the TRWPs and leached rubber chemicals. Recent studies have demonstrated the widespread occurrence and toxicity of TRWPs and their associated chemicals (e.g. 6PPD, 6PPD-quinone, benzothiazoles, phthalate esters, polycyclic aromatic hydrocarbons, etc.) in both aquatic and terrestrial environments. The Kansas Water Science Center's (KS WSC) Organic Geochemistry Research Laboratory (OGRL) is conducting research to further understand the ecological impacts of these ubiquitous anthropogenic materials which necessitates an interdisciplinary approach to address the many knowledge gaps relating to the sources, transport, fate, toxicity, and reduction strategies of TRWPs and their associated chemicals.
6PPD-quinone is a transformation product of 6PPD, an antiozonant used in tires.
Currently, 6PPD is used in all tires and can contaminate stormwater anywhere tires are used.
The rubber-derived ozone transformation product 6PPD-quinone (6PPDQ) was discovered in 2020 as a causative agent for urban runoff mortality syndrome in coho salmon. Tire and road wear particles are mobilized during urban storm events and transport 6PPD-quinone into surrounding aquatic ecosystems with concentrations that exceed acute toxicity thresholds for several salmonid species and the Environmental Protection Agency’s (EPA) aquatic life screening values of 11ng/L. These urban runoff events create sampling challenges and storm chasing to capture and characterize the transient exposure.
The widespread use of rubber in products such as tires and the documented harmful environmental effects necessitates an improved understanding of the occurrence, fate, and bioavailability of 6PPD-quinone.
Highlighted Science
After the discovery of the tire antiozonant transformation product 6PPD-quinone in 2020, research into rubber antiozonants chemicals began in earnest. The KS WSC OGRL developed a method for the analysis of 6PPD and 6PPD-quinone in water in 2021 to support toxicological studies and understand the environmental prevalence, fate, and bioavailability. The analytical method was published in 2024 to inform sampling procedures and hold times and advance understanding of stream exposures. Results from a nationwide reconnaissance of 6PPD and 6PPD-quinone in surface waters from 94 sites with varying land-use (urban, agricultural, and forested) and streamflow found that storm events mobilize 6PPD-quinone primarily from urban watersheds; downstream concentrations exceeded EPAs recently released 6PPD-quinone 11 ng/L freshwater acute aquatic life screening value for the protection of aquatic life. https://doi.org/10.1016/j.chemosphere.2024.142830
- With a short half-life, 6PPD has a low aqueous detection frequency
- Urban-impacted stormwater has the highest observed aqueous concentrations of 6PPD-quinone
- 6PPD-quinone stream exposures are transient pulse(s) at concentrations toxic to coho salmon.
- Sampling protocols and monitoring should account for the episodic nature of exposure.
In FY25 research is continuing at the KS WSC OGRL to advance knowledge about the ecosystem occurrence, partitioning, and fate of 6PPD and 6PPD-quinone:
- Ecological Implications of 6PPD/6PPD-quinone Partitioning: Occurrence of 6PPD and 6PPD-quinone in suspended and bed sediments
- Passive Sampling: Use of diffusive gradients in thin film (DGT) passive samplers for 6PPD-quinone
- Bioavailability (Occurrence Sampling): collaborative studies across the USGS to determine 6PPD and 6PPD-quinone levels in ecologically relevant habitats
- Toxicology Studies: collaborations with USGS Western Fisheries Research Center and Columbia Environmental Research Center exploring facets of 6PPD and 6PPD-quinone toxicity
- Method Validation: Participation in an inter-laboratory validation study and seeking accreditation with Washington State Department of Ecology
6PPD
- N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine
- Tire antiozonant that prevents rubber breakdown
- Ozone in the atmosphere interacts with tires
6PPD-quinone
- 6PPD and ozone reaction protects the tire, but also produces 6PPD-quinone (6PPDQ)
Current Analytical Capabilities
Methods for 6PPD-quinone and 6PPD
Analysis Code: LCTR
Direct Inject Water Method
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Water
Reporting Limit: 0.002 µg/L
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Analysis Code: LCTR-EPA
EPA Draft Method 1634
Instrumentation: liquid chromatography/tandem mass spectrometry
Matrix: Water (predominantly stormwater and surface water)
Reporting Limit: 2.00 ng/L
Compound/CAS#:
6PPD-quinone / 2754428-18-5
In Development
Analysis Code: LCTW
Whole Water (Aqueous and Suspended Material) Method
Sample Prep: Energized Dispersive Guided Extraction and Solid-phase extraction
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Stormwater or Turbid Waters
Reporting Limit: in development
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Analysis Code: LCTS
Solid Method
Sample Prep: Energized Dispersive Guided Extraction and Solid-phase extraction
Instrumentation: Liquid chromatography/tandem mass spectrometry
Matrix: Sediments and Soils
Reporting Limit: in development
Compound/CAS#:
6PPD-quinone / 2754428-18-5
6PPD/ 793-24-8
Contact Rachael Lane (785-760-4540; rflane@usgs.gov) for details about bottles or additional tire wear compounds of interest
Highlighted Outreach
- ITRC Tire Anti-Degradants (6PPD) Guidance Document (publication Fall 2025) Tire Anti-Degradants (6PPD) - ITRC (itrcweb.org)†
- Lane, R.F. subgroup co-lead for Environmental Assessments Strategies chapters
- Lane R.F. subgroup co-lead Training and Outreach material for 6PPD and 6PPD-quinone
- Lane, R.F. (Presenter, Invited) 2023. Analytical Capabilities for 6PPD. ITRC Tire Anti-Degradants (6PPD) Monthly Meeting
- Lane, R.F. 2025. ITRC 6PPD CLU-IN Trainer
-
Lane, R.F (Presenter, Invited), Kolpin, D.W.; Bradley, P.M., Smalling, K.L. 2023. Understanding the environmental occurrence and fate of the tire leachate transformation product 6PPD-Quinone. USGS CMWSC Seminar Series
† 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.