The Environmental Assessment Program at Washington Department of Ecology is conducting 6PPD-quinone (6-PPDQ) research and monitoring to understand the impacts on aquatic life. Trace amounts of 6-PPDQ cause coho salmon mortality within hours of exposure. Ecology and university partners are conducting additional tire chemical toxicity studies on other resident aquatic life while seeking safer alternatives to 6PPD in tires. Ecology and partners are conducting sampling surveys of critical areas, such as small urban streams and wetlands, to understand where 6-PPDQ is limiting biological recovery of urban watersheds. The sampling results will be used to locate toxic reduction corrective actions.
GOAL: The toxics ecosystem assessment data will be used to locate corrective actions to protect aquatic life from road runoff within priority watersheds. Priority watersheds refer to those chosen by regional community and technical advisory groups.
BONUS: These efforts will provide critical baseline data that can monitor the success of our corrective actions.
Toxics Ecosystem Assessment Plan for 6-PPDQ
2025- continue 6-PPDQ ecosystem assessments to identify vulnerable aquatic ecosystems impacted by urban road runoff and integrate data into ongoing stormwater mapping and modeling efforts.
2024 - began to implement the toxics ecosystem assessment strategies to verify critical areas of concern using 6-PPDQ as an urban runoff proxy.
2022 - convened salmon and mapping domain experts who developed mapping strategies to identify priority watersheds.
2025
Toxics Ecosystem Assessments Plan
Technical memos will be published for provisional studies.
The integrated urban watershed study will continue; stream water quality and quanity (flow) and 6-PPDQ concentrations are measured at 2 hour intervals for 24 hours during storm events to correlate the persistence and peak concentrations of 6-PPDQ persists with stream biological indicators. The relationship could be applied to Ecology's Watershed Health Program and local communities that use a standardized metric for biological health (B-IBI).
Source idenfication assessments will continue that compare 6-PPDQ mass loadings among streams in priority watersheds, these surveys are a joint effort with many partners.
6-PPDQ in marine sediment samples will be collected throughout the Puget Sound as an indicator of urban runoff impacts.
Science staff will continue to participate in interstate, tribal and federal coordination groups and build collaborative relationships with partners.
Science staff will continue to provide technical guidance for funded 6-PPDQ projects and WA Tribes.
An urban road runoff technical advisory committee shared research updates, prioritized data gaps, and developed strategies to visualize and focus where 6-PPDQ is impacting vulnerable aquatic life. A summary of recommendations and current knowledge was published in a 6PPD in Road Runoff Legislative Report. This process of evaluating the current knowledge regarding the impact of tire contaminants on aquatic life helped galnanize pro-active state, tribal and federal working groups to address the tire contaminant problem. Please find the a list of the presentations for each meeting below and the final report that also included an evaluation of Best Management Practices (BMPs) to implement at locations where 6-PPDQ is impacting vulnerable species.
Identifying Priority Areas for Corrective Actions to Reduce Urban Runoff Impacts to Aquatic Life
Integration of urban stream and wetland quality and quantity will accelerate recovery of aquatic ecosystems.
To identify where to protect species and habitats from urban runoff, we need to know where and when they are being exposed to 6-PPDQ.
6-PPDQ peak concentrations in urban small streams and wetlands should be used as a metric for project prioritizations.
Tribal Treaty Rights is a priority.
Human health benefits is a priority.
Protecting and restoring small streams and coho salmon habitat is a priority.
Toxicity studies of additional Washington resident aquatic life is a priority data gap.
The fate and transport of 6-PPDQ in the evironment is a priority data gap.
Evaluating Stormwater Best Management Practices that Reduces 6-PPDQ in Urban Runoff
Several strategies were identified to be, most likely, effective at reducing the discharge of 6-PPDQ to receiving waters:
Source control BMPs, for example street sweeping and line cleaning
Structural BMPs that that mimic natural filtration processes and minimize impervious surfaces, for example, green infrastructure, low impact development, and emerging technologies.
Status of Recommendations from Report
Identifying Priority Areas for Corrective Actions to Reduce Urban Runoff Impacts to Aquatic Life
Stormwater SIL funded local entities to conduct local 6-PPDQ prioritizations, EAP science staff have provided technical guidance and logistical support.
MTCA funds were awarded to Ecology to evaluate sampling methods, develop analytical lab methods and a study design to assess 6-PPDQ in urban waterways, and fund UW-Tacoma to evaluate fate and transport data gaps.
Continued MTCA funds are being requested for the toxics ecosystem assessments.
UW-Tacoma has since received funding from other Ecology/EPA funding programs.
A project to inventory and integrate stream and wetland habitat quality and quantity for each salmon recovery watershed has not been funded.
Evaluating Stormwater BMPs that reduces 6-PPD in road runoff
Stormwater SIL and other stormwater funding programs have invested in research to evaluate BMP effectiveness
MTCA funds were awarded to Ecology to fund additional BMP effectiveness studies.
Examining the direct and indirect impacts of anthropogenic stressors on stream macroinvertebrate communities at multiple spatial scales: a structural equation modeling approach