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Department of Ecology
Committees, Boards, and Workgroups

6PPD Stormwater Best Management Practices Research

 This page is run by the Washington State Department of Ecology and is a space for sharing publications from 6PPD stormwater research.

Ecology is supporting several research projects and identifying best management practices (BMPs) that are effective at managing 6PPD and 6PPD-quinone (6PPDQ) in stormwater. These studies will help inform appropriate policy, regulatory, and rulemaking processes around 6PPD and 6PPDQ to protect aquatic life, ecosystems, and human communities. 

Funding Announcement

Ecology's 6PPD Team anticipates receiving $2.9 million for new 6PPD stormwater BMP effectiveness research. This funding will support 2 years of research from July 2025 - June 2027. Qualifying funding recipients include Tribal Nations and public organizations as defined by RCW 39.34.020​. 

If you have a project idea, reach out to Madison at madison.bristol@ecy.wa.gov to set up an initial meeting. There is no application for this funding, and project scopes will be developed collaboratively between Ecology and contracted partners. Though there is no deadline for proposals, pitches received between April - June 2025 and projects led by or in collaboration with Tribal Nations will be prioritized for funding.

Project topics could include, but are not limited to:

  • Testing already installed stormwater best management practices (BMPs) in the field. BMPs could include: Street sweeping, decant facilities, grassy swales, floating wetlands, road embankments, sorbent media, bioretention soil mixes, media filters, proprietary treatment (TAPE) devices, etc. ​
  • Assessing the effectiveness of treatment trains and whole stormwater systems
  • Evaluating BMP maintenance practices and cost effectiveness
  • Sampling influent concentrations for diverse land uses​
  • Understanding how 6PPDQ moves through and persists in the environment​ (i.e. fate and transport)
  • Synthesizing research results and developing 6PPDQ management guidance for permittees and communities

Scroll down this website to view example projects supported by this funding.

 

Summary Publications

The following publications provide a big picture overview of our 6PPD BMP effectiveness research: 

 

Overview of Research Projects

We describe each of our research projects below, including:  

 

List of Research Projects

To learn about research projects, click on the project below or scroll down this page. 

Completed Research

 

Ongoing Research

 

Completed Research 

Herrera Environmental Consultants - 6PPDQ in Highway Runoff, BMP Effectiveness, and Field Protocol Development 

Description: Testing influent and effluent with TAPE devices for removal of 6PPDQ in Seattle and Portland    
Funded By: Ecology’s 6PPD Funding 
Contact: Madison Rose Bristol, madison.bristol@ecy.wa.gov  
 
Publications: 

King County - Testing Removal of 6PPDQ and Coho Salmon Lethality by High Performance Bioretention Media Blends 

Description: Testing 4 high performance bioretention soil mixes in a bench-scale, laboratory study  
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov 
 
Publications: 

Osborn Consulting Inc & Evergreen StormH2O - Stormwater Treatment of Tire Contaminants Report 

Description: Produced a literature review assessing the potential effectiveness of common BMPs at addressing tire wear particles  
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov    
 
Publications: 

Pierce County - 6PPD-quinone Removal in Decant Facility 

Description: Full-scale decant facility removal of 6PPDQ, including assessing the effectiveness of granular activated carbon  
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov  
 
Publications: 

University of Washington - Tacoma - Development of Chemical Indicators to Detect, Track, and Assess Pollutants  

Description: Assessed the effectiveness of seven stormwater treatment systems for managing select salmonid toxicants, including a mix of Zeolite, Perlite, and granular activated carbon, bioretention systems with compost media, and bioswales
Funded By: Stormwater SIL 
Contact: Michelle Myers, michelle.myers@ecy.wa.gov 
 
Publications: 

University of Washington - Tacoma - Evaluation of 6PPDQ Treatment using Soils and Sorbent Media 

Description: Comparing the contaminant capture of engineered medias, commercial sorbent components, and simplified soils  
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov 
 
Publications: 

 

Ongoing Research

City of Redmond - Paired Retrofit & Restoration Watershed Study 

Description: Reducing contaminants in receiving waters through street sweeping  
Funded By: Ecology’s 6PPD Funding, SAM 
Contact: Chelsea Morris, chelsea.morris@ecy.wa.gov  
 
Publications: 

City of Spokane - Bioretention Soil Media Study: Development of Non-Vegetated BMPs

Description: Evaluates the effectiveness of bioretention soil mix (BSM) and high performance bioretention soil mix (HPBSM) at removing stormwater pollutants, including 6PPDQ, at a full-scale facility when they are installed without vegetation 
Funded By: Ecology’s 6PPD Funding, WQ CFP
Contact: Shilo Sprouse, shilo.sprouse@ecy.wa.gov 
 
Publications: 

City of Tacoma - Characterization of Stormwater Transport of Contaminants of Emerging Concern in Western Washington

Description: Building a dataset of contaminants of emerging concern concentrations from stormwater outfalls associated with urban land uses     
Funded By: Ecology’s 6PPD Funding, SAM 
Contact: Chelsea Morris, chelsea.morris@ecy.wa.gov 
 
Publications: 
  • Project Website
  • Proposal (2023)
  • Literature Review (2024) 
  • Quality Assurance Project Plan (2025) 
  • Final Research Report (2027) 
  • Research Report Focus Sheet (2027) 
  • Presentation (2027) 

City of Tacoma - Sediment Method Development

Description: Produces a method for 6PPDQ testing in sediment    
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov 
 
Publications: 

EA Engineering, Science, and Technology Inc., PBC - The Use of Unamended Soils for Treatment of 6PPDQ in Stormwater: Persistence, Soil Types, and Influence of Vegetation 

Description: Comparing the persistence and reduction of 6PPDQ in unamended and amended soils and evaluating potential uptake in vegetation   
Funded By: Ecology’s 6PPD Funding 
Contact: Madison Rose Bristol, madison.bristol@ecy.wa.gov  
 
Publications: 
  • Economic Analysis Report (2025) 
  • Economic Analysis Focus Sheet (2025) 
  • Final Research Report (2025) 
  • Research Report Focus Sheet (2025)
  • Presentation (2025) 

King County - King County Multi-Criterion Decision Tool to Address 6PPDQ and Tire Wear Particles

Description: Testing the effectiveness of grassy roadside embankments and developing a web-based Screening Model to estimate 6PPDQ generation from roadway types  
Funded By: Stormwater SIL, Ecology's 6PPD Funding
Contact: Michelle Myers, michelle.myers@ecy.wa.gov 
 
Publications: 
  • Factsheet (2024)
  • Modeling quality assurance project plan (2024)
  • Technical memo for 6PPDQ spatial layer (2024)
  • Sampling quality assurance project plan (2025)
  • Road segment prioritization report (2025)
  • Online webtool with 6PPDQ spatial layer (2025)
  • Site screening technical memo (2025)

King County - Treatment effectiveness of a Full-scale Stormwater Facility using High Performance Bioretention Soil Media for 6PPD-quinone and other Toxic Chemicals 

Description: Testing high performance bioretention soil media at a full-scale facility  
Funded By: Ecology’s 6PPD Funding, SAM 
Contact: Chelsea Morris, chelsea.morris@ecy.wa.gov  
 
Publications: 

King County Environmental Lab - Characterizing Stormwater Pollutant Concentrations in Mixed Residential and Highway Runoff in Seattle 

Description: Characterizing stormwater from a mixed highway and residential land use  
Funded By: Ecology’s 6PPD Funding 
Contact: Madison Rose Bristol, madison.bristol@ecy.wa.gov  
 
Publications: 

Long Live the Kings – Ohop Creek Stormwater Filtration Effectiveness Study 

Description: Assessing the treatment effectiveness of a compost and stormwater biofiltration system and its ability to reduce 6PPDQ in Ohop Creek
Funded By: Stormwater SIL
Contact: Michelle Myers, michelle.myers@ecy.wa.gov    
 
Publications: 
  • TBD

The Nature Conservancy - Puget Sound Stormwater Heatmap Version 2.0 

Description: Developing a user accessible Stormwater Heatmap tool to support local jurisdictions in stormwater retrofit long-term planning, which includes pollution hot spots, hydrology, and climate modeling 
Funded By: Stormwater SIL
Contact: Michelle Myers, michelle.myers@ecy.wa.gov    
 
Publications: 

NV5 - Verification of BMP Effectiveness, Crumb Rubber Investigation, and Street Sweeping and Traffic Density Characterization

Description: Verifying the effectiveness of BMPs in the BMP Effectiveness Report, testing for 6PPDQ from land uses with crumb rubber, and street sweeping frequency needs  
Funded By: Ecology’s 6PPD Funding 
Contact: Shelby Giltner, shelby.giltner@ecy.wa.gov   
 
Publications: 

Seattle Public Utilities - Measuring Street Sweeping 6PPDQ Whole Environment Load Reductions 

Description: Estimate the amount of 6PPDQ removed from the roadway with street sweeping
Funded By: SAM 
Contact: Chelsea Morris, chelsea.morris@ecy.wa.gov  
 
Publications: 
  • Proposal (2023)
  • Quality Assurance Project Plan (2024)
  • Final Research Report (2028) 
  • Research Report Focus Sheet (2028) 
  • Presentation (2028)

Stewardship Partners – Scaling Adopt-a-Downspout for the Treatment of Toxic Roadway Pollutants

Description: Scaling up an Adopt-a-Downspout (AAD) system that has been proven to reduce 6PPDQ and other toxic chemicals
Funded By: Stormwater SIL
Contact: Michelle Myers, michelle.myers@ecy.wa.gov    
 
Publications: 

Snoqualmie Indian Tribe - Testing 6PPD-quinone on the Snoqualmie Reservation 

Description: Characterizing parking lot runoff and assessing the effectiveness of floating wetlands, swales, and native vegetation  
Funded By: Ecology’s 6PPD Funding 
Contact: Madison Rose Bristol, madison.bristol@ecy.wa.gov  
 
Publications: 

University of Washington - Tacoma - Enhanced Watershed Monitoring & Toxicological Analysis of CECs  

Description: Filling data gaps in the spatial and temporal variation of contaminants of emerging concern (CECs), including 6PPDQ, using passive sampling in the Puyallup and Stillaguamish watersheds 
Funded By: Stormwater SIL 
Contact: Michelle Myers, michelle.myers@ecy.wa.gov 
 
Publications: 
  • TBD

University of Washington - Tacoma - Sampling, Occurrence, and Toxicity of 6PPD-quinone and Related Chemicals 

Description: Characterizes 6PPD, 6PPDQ and other PPD-quinone concentrations and dynamics in key small watersheds of the Puyallup, Nisqually, Deschutes, and the South Sound  
Funded By: Stormwater SIL 
Contact: Michelle Myers, michelle.myers@ecy.wa.gov 
 
Publications: 

Washington State University – Pilot Study Evaluating Stormwater Facilities and BMPs for 6PPDQ Mitigation

Description: Assessing the effectiveness of wet ponds and stormwater ditches retrofitted with media-filled check dams
Funded By: Stormwater SIL
Contact: Michelle Myers, michelle.myers@ecy.wa.gov    
 
Publications: 

Washington State University - Puyallup - Longevity of Bioretention Depths for Preventing Acute Toxicity from Urban Stormwater Runoff 

Description: Testing the longevity of bioretention media  
Funded By: Ecology’s 6PPD Funding, SAM 
Contact: Chelsea Morris, chelsea.morris@ecy.wa.gov  
 
Publications: 

Washington Stormwater Center - Synthesis of Street Sweeping Research & Practices: Guiding Program Development & Implementation 

Description: Developing a guidance manual to assist MS4 permittees with improving their street sweeping programs  
Funded By: Ecology’s 6PPD Funding 
Contact: Madison Rose Bristol, madison.bristol@ecy.wa.gov 
 
Publications: 

 

Additional 6PPD Work 

Ecology is addressing 6PPD and 6PPDQ through several efforts. For more information about our agency’s 6PPD work beyond BMP effectiveness research, please visit these websites: 

 

Contact Us

For questions or feedback about this page, please contact Madison Rose Bristol, 6PPD Stormwater Planner, at madison.bristol@ecy.wa.gov. 

 

Documents

 File NameFile SizeDescriptionCategoryDate Added
InitialFactsheet_SIL2.0_Final_050924.pdf 407.8 KB Factsheet
Factsheet
King County 08/15/24 03:02 PM
Task1.2.02023-12-15InitialProjectFactsheetSIL2.0.pdf 441.7 KB Factsheet
Factsheet
The Nature Conservan... 08/15/24 03:08 PM
TNC Stormwater Heatmap V2.0 NEP Quality Assurance Project Plan 2024.pdf 1.8 MB QAPP
QAPP
The Nature Conservan... 08/15/24 03:10 PM
NEP_Factsheet_ChemIndicators_FINAL Factsheet.pdf 636.7 KB Factsheet
Factsheet
UW-Tacoma 08/15/24 03:14 PM
1.2 InitialFactsheet_SSTIF_EPK_032924.pdf 586.9 KB Factsheet
Factsheet
UW-Tacoma 08/15/24 03:19 PM
FINAL TAPE QAPP SIGNED.pdf 15.9 MB QAPP
QAPP
City of Spokane 10/10/24 02:47 PM
Project Schedule.pdf 55.9 KB Schedule
Schedule
City of Spokane 10/10/24 02:48 PM
TESTSITEPLANSHEETS.pdf 2.2 MB Site Plan
Site Plan
City of Spokane 10/10/24 02:49 PM
23-08026-000_23-24-6PPDQ-BMP-Eff_20240904_rev1.pdf 15.1 MB 2023-2024 Herrera Final Report
2023-2024 Herrera Final Report
Herrera Environmenta... 12/19/24 11:24 AM
23-08026-000_TM_6PPDqFieldProtocols_20240903_rev1.pdf 417.6 KB Herrera Technical Memorandum
Herrera Technical Memorandum
Herrera Environmenta... 12/19/24 11:24 AM
ECY executed 23-08026-000_QAPP-6PPD-Q_20230515 (1).pdf 2.6 MB Herrera QAPP
Herrera QAPP
Herrera Environmenta... 12/19/24 11:41 AM
Quality Assurance Project Plan Addendum.pdf 905.5 KB Herrera QAPP Addendum
Herrera QAPP Addendum
Herrera Environmenta... 12/19/24 11:41 AM
Quality Assurance Project Plan for Stormwater Characterization for BMPs Study-signed (1).pdf 1 MB KCEL QAPP
KCEL QAPP
KCEL 02/13/25 01:15 PM
FINAL Ecologyreview _Sorption_Report_020324 (2).pdf 3.2 MB Final Report
Final Report
UW-Tacoma 02/20/25 02:49 PM
QAPP_CUW Treatment Media_012523_Executed (1).pdf 5.8 MB QAPP
QAPP
UW-Tacoma 02/20/25 02:52 PM
QAPP KC HPBSM 6PPDQ 030323 Final All (4).pdf 2.9 MB KC HPBSM QAPP
KC HPBSM QAPP
King County 02/20/25 03:17 PM
King_County_Lab_6PPDQ_Study_Report_Final (1).pdf 19.9 MB KC HPBSM Data Summary Report
KC HPBSM Data Summary Report
King County 02/20/25 03:21 PM
Science_Stories_Mitchell_HPBSM_6PPDq (2).pdf 4.3 MB King County Science Stories
King County Science Stories
King County 02/20/25 03:29 PM
QAPP_6PPD-quinone Removal in Decant Facility (002).pdf 2 MB
#NEW_CATEGORY# 02/20/25 03:40 PM
6PPD-Quinone Removal in Decant Facility.pdf 2.8 MB
Pierce County 02/20/25 03:44 PM
5041_6PPD-Quinone Soil Extraction and analysis by Triple Quadrupole LC-MS-MS_v3 (002).pdf 1.7 MB Sediment SOP
Sediment SOP
#NEW_CATEGORY# 04/17/25 02:42 PM

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