Biomonitoring of Contaminants in the Puget Sound Nearshore
WASHINGTON STATE MUSSEL WATCH PROGRAM
Program and Partners
WDFW Monitors Chemical Contaminants in the Nearshore
Toxic contaminants originating from human activities, such as fuel combustion and industrialization, are continuing to be introduced to the environment and are of growing concern to marine ecosystems. Many of these contaminants are chemicals that are often persistent in the environment, bioaccumulate in living organisms, and can be toxic even at low concentrations. They enter the Puget Sound, within the Salish Sea waters of Washington State, from numerous pathways including nonpoint sources such as surface water runoff and air deposition, focal non-point sources such as marinas and ferry terminals, and point sources such as discharges from stormwater outfalls and wastewater treatment plants.
Such toxic substances can cause harm to aquatic organisms and pose a risk to the people who consume them. Monitoring toxic contaminants in Puget Sound is a critical component of tracking its recovery and informing remediation efforts. Monitoring in the nearshore is specifically important because this habitat is the interface between land and water that defines where and when many toxics enter Puget Sound. Understanding the extent and magnitude of toxics in nearshore species improves the ability to mitigate the harm pollution causes in the nearshore environment.
In 2012, the Washington Department of Fish and Wildlife's Toxics Biological Observation System (TBiOS) team established a long-term program to monitor toxic contaminants in the Puget Sound nearshore using translocated, caged native bay mussels (Mytilus trossulus) as the primary indicator organism ( Lanksbury et al., 2014 ). WDFW’s Washington State Mussel Watch (WAMW) program aims to assess the geographic extent and magnitude of toxic contaminants in the nearshore (status) and determine whether conditions are improving, remaining the same, or getting worse over time (trends).
Every other winter, relatively clean (uncontaminated) mussels sourced from a local aquaculture source are transplanted to over 80 nearshore sites throughout the Puget Sound, including a few on the Washington Pacific coast shoreline. After a three-month exposure period, the tissues from the mussels are analyzed for a suite of contaminants including persistent organic pollutants (e.g., PCBs, PAHs), metals (e.g., lead, copper), and contaminants of emerging concern (e.g., pharmaceuticals and personal care products).
Bay mussels (Mytilus trossulus) from Penn Cove Shellfish, Whidbey Island, WA.
Data from this WDFW program provides information on the health of biota living in the nearshore and supports management programs such as the Washington Department of Ecology's Stormwater Action Monitoring (SAM) program and NOAA's National Mussel Watch Program (MWP). The WDFW program also provides information on progress towards Puget Sound recovery goals, reporting results to the Puget Sound Ecosystem Monitoring Program's (PSEMP) - Toxics in Aquatic Life Vital Sign . Though the WDFW program is largely supported by Washington State agencies and federal programs, local governments, tribes, NGOs, and other interest groups sponsor additional sites of interest or concern. A wide network of support from federal, state, and local groups has allowed us to monitor across a wide geographic area.
Organizations that have sponsored mussel monitoring sites include the Washington State Department of Ecology (ECY) Stormwater Action Monitoring Program, NOAA National Mussel Watch Program, Washington Department of Natural Resources (DNR) Aquatic Reserves Program, King County DNR Water and Land Resources Division, Kitsap County Public Works, Pierce County Planning and Public Works, Tacoma-Pierce County Health Department, Snohomish County Surface Water Management, Jefferson County Public Health, Jefferson County Marine Resources Committee (MRC), Snohomish County MRC, Whatcom County MRC, San Juan County MRC, City of Bellingham, Port of Tacoma, Stillaguamish Tribe, Tulalip Tribe, Port Gamble S'Klallam Tribe, Jamestown S'Klallam Tribe, Makah Tribe, Bainbridge Beach Naturalists, Puget Soundkeeper Alliance, Rich Passage Estates Homeowners' Association, SSA Marine.
Stormwater Action Monitoring
Contaminated stormwater is considered one of the biggest contributors to water pollution in the urban areas of Washington State. Monitoring pollutants from contaminated stormwater and their effects on the marine biota of Puget Sound is critical to inform best management practices and remediation efforts.
The Washington State Department of Ecology's Stormwater Action Monitoring (SAM) Status and Trends in Receiving Waters program conducts monitoring in Puget Sound small streams and nearshore marine waters to provide a regional assessment of whether collective stormwater management actions are leading to improved receiving water conditions. The WDFW Mussel Watch Program supports SAM efforts, implementing their Puget Sound Nearshore surveys which aims to characterize the spatial extent of contamination to which nearshore biota are exposed and to track changes in tissue contamination over time. Three surveys were conducted, beginning in odd numbered years, between 2015-2020 with WDFW monitoring 40 sites at locations along the urban growth area (UGA) shorelines of Puget Sound.
The SAM Nearshore surveys has since continued under a new study design , expanding from the Urban Growth Area to the whole Puget Lowland nearshore area. A Quality Assurance Project Plan for the 2021 to 2025 monitoring period is available with study design details, the geographic scope of the study, study participants, objectives and goals, field sampling procedures, laboratory processing of mussels, analytical chemistry, and measurement quality objectives. The 2021-2022 survey year was the first completed under this new study design.
Results from each survey are described in the reports listed below and data are available in Washington State Department of Ecology's Environmental Information Management System (search Study ID SAM_MNM).
National Mussel Watch Program
Since 1986, NOAA's National Mussel Watch Program (MWP) remains the longest running continuous contaminant-monitoring program in U.S. coastal and Great Lakes waters. The program utilizes a sentinel-based approach to monitoring, by collecting and analyzing sediment and bivalves (oysters and mussels) as surrogates for water pollution and bioaccumulation at a network of nearly 300 coastal sites including the Great Lakes, Alaska, Hawaiʻi, and Puerto Rico. Nearly 600 chemical contaminants, including metals, legacy organic compounds, and chemicals of emerging concern (CECs) are analyzed. The program’s long-term data describes the status and trends of chemical contamination in the nation’s estuarine and coastal waters. Further, it supports the assessment of potential impacts of unforeseen events such as oil spills and hurricanes, as well as evaluating the effectiveness of regulations that ban toxic chemicals or support legislation such as the Clean Air and Clean Water acts.
The program was recently redesigned to adopt a rotating regional approach, with the Pacific Northwest region (WA and OR) monitored every five years. The most recent visits to our region occurred in the 2019-2020 and 2023-2024 surveys, where 15-16 historic NOAA Mussel Watch sites were successfully resampled using WDFW's transplanted cage methodology in place of sampling wild mussels.
NOAA Mussel Watch Program data can be explored on the Coastal Pollution Data Explorer .
Using Transplanted Mussels as a Nearshore Indicator for the Toxics in Aquatic Life Vital Sign
The Puget Sound Partnership (PSP or “Partnership”) is the state agency leading Washington’s collective effort to protect and restore Puget Sound by collaborating with partners, such as the Washington Department of Fish and Wildlife (WDFW), to assess recovery progress and implement policy solutions that protect environmental and community wellbeing. To gauge the health of Puget Sound, the Partnership utilizes a monitoring system called Vital Signs. There are 23 Vital Signs, each with their own associated indicators. The Washington State Mussel Watch program supports the Toxics in Aquatic Life Vital Sign , and specifically the “ Contaminants in caged mussels ” indicator.
The “Contaminants in caged mussels'' indicator was recently adopted by The Puget Sound Partnership Leadership Council to address the priority needs of reporting status and trends of toxic contaminants in the nearshore. Importantly, this indicator was selected to redress a longstanding spatial gap in monitoring toxic chemicals in nearshore habitats. The addition of mussel monitoring augments existing Toxics in Aquatic Life (TIAL) indicators already tracking toxics in organisms in pelagic (open water), benthic (seafloor) and river/estuary habitats. Monitoring the geographic extent and magnitude of contaminants in the nearshore using caged mussels intends to guide strategies to prevent contaminants from entering the Sound. Further, tracking changes in nearshore contamination through time will direct attention to areas where toxics may be increasing and identify where remediation strategies have been successful in lowering contaminants.
Mussels at Work
Why use mussels as our monitoring species?
Mussels are a widely used biomonitoring species in toxic contaminant monitoring programs around the world. As filter feeding organisms they uptake large amounts of seawater, concentrating contaminants in their tissues until reaching equilibrium with the local environment, and retaining them for approximately two to four months. Additionally, mussels have a limited capacity to metabolize many of the contaminants they take in, making them a good indicator species for contaminants that are quickly metabolized (e.g., PAHs) by other marine organisms such as fish.
Using transplanted caged mussels
Our monitoring program uses a clean aquaculture source of native bay mussels (Mytilus trossulus) that are transplanted to their monitoring locations in anti-predator cages, which are left on site for three months during the winter. Advantages to using transplanted mussels instead of wild mussel populations include fewer limitations on study locations, a uniform starting population, a known exposure period, and the ability to measure and compare certain biological endpoints (e.g., growth, body condition, mortality).
Bagged mussels in a predator exclusion cage at a nearshore monitoring site.
Our mussels are generously provided by Penn Cove Shellfish, LLC , located in Coupeville, Whidbey Island, WA. Every survey, Penn Cove Shellfish donates thousands of mussels and supports our efforts in preparing and bagging mussels that are ultimately deployed to our monitoring sites.
Sound Water Steward Volunteers and WDFW-TBiOS staff complete a line of bagged mussels for later deployment in cages to sites throughout Puget Sound.
Monitoring Sites and Contaminants
Monitoring Sites
Since 2012, we have conducted surveys every other year, completing 5 surveys to date, and visited over 200 unique sites throughout Puget Sound, plus a few locations on the WA Pacific Coast! As can be seen in the map, we thoroughly cover all regions of Puget Sound that include nearshore areas with various upland types, ranging from low to high development, and including urban and agricultural areas. Many of the sites have been visited more than once. The site symbol shows the most recent survey year visited (click on site symbol to view site location details for each survey year).
Since our partnership with the Stormwater Action Monitoring (SAM) program, up to half of our sites are randomly selected under the SAM study design . The remaining sites are comprised of our partnerships with NOAA and other local government agencies, tribes, and individuals with unique interests in a particular location. Over the years, around 25 different organizations have sponsored up to 143 monitoring sites. By sponsoring additional sites, our partners have greatly added to the scope of our larger monitoring program.
Contaminants Monitored
Our monitoring program routinely analyzes for a suite of legacy organic contaminants, which includes PAHs, PCBs, PBDEs, and DDTs, along with several other organochlorines. PAHs, PCBs, PBDEs, and DDTs have been identified as important monitoring chemical classes in other monitoring species due to their persistence, geographic extent and magnitude, and risk to human or aquatic species health. They also broadly track back to unique contamination pathways or sources such as stormwater, wastewater, or point sources.
WDFW Mussel Watch has identified widespread exposure of PCBs and PAHs in nearly all nearshore habitats monitored in Puget Sound. These two contaminants are the most frequently occurring (detected at all our sites) and their levels greatly exceed the other chemicals currently being monitored. As the most ubiquitous and high magnitude organic contaminants, we further report on these two contaminants in the nearshore in the following sections. Future iterations of this story map may include results on other monitored contaminants.
Listed below are contaminants analyzed at our partner laboratories - NOAA Northwest Fisheries Science Center Environmental Chemistry Laboratory , King County Environmental Lab , and SGS AXYS .
Organic compounds: polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides - DDTs, chlordanes, HCB, aldrin, dieldrin, HCHs, endosulfan 1, mirex
Metals: arsenic, cadmium, copper, lead, mercury, zinc
Contaminants of Emerging Concern (CECs): pharmaceuticals and personal care products, perfluorinated compounds (PFOS, PFAS), alkylphenols, current use pesticides, tire rubber compounds (6PPD-Q)
PCBs
The lower Duwamish River, a federal Superfund site near Seattle, WA where PCB contamination persists.
What are PCBs?
Polychlorinated biphenyls (PCBs) are persistent organochlorine compounds once widely used as coolant fluids in electrical devices (e.g., lamp ballasts and transformers), in carbonless copy paper, and in heat transfer fluids. They were also used in a variety of building materials such as plasticizers in paints and cements, stabilizers in PVC coatings, and in sealants for caulking and adhesives.
PCBs are known to cause a variety of adverse health effects in animals, including cancer, impairment to immune systems, behavioral alterations, and impaired reproduction. Negative impacts specific to mussels have also been demonstrated, with a reduced scope for growth, fecundity, and survival. PCBs are also probable carcinogens in humans, interfere with hormone systems, and have neurotoxic effects.
How do PCBs enter the nearshore?
Possible PCB contamination pathways.
There were several PCBs spills in Puget Sound, particularly in the Duwamish River in the 1960s and 70s, and PCBs from those spills are still found in sea floor sediments and the water column. Although the manufacture of PCBs in the United States was largely banned in 1979, they are still found in significant amounts in the Puget Sound basin (e.g., in building paints and caulks), and continue to find their way into stormwater.
Identifying Local Sites of Concern for PCBs
The adjacent map compares PCB concentrations (ng/g, dry weight) in mussels between individual monitoring sites (zoomed in) or site clusters (aggregated sites, zoomed out) which can be used to identify local sites/areas of concern, or contaminant "hotspots". An individual site represents local nearshore conditions - approximately eight hundred meters of shoreline. The monitoring sites were visited during the five biennial surveys conducted between 2012 and 2022, with some sites visited more than once. The site colors represent increasing concentrations in four categories based on the quantile distribution of the 2012 to 2022 data collected. Dark blue represents the lowest concentration category, light blue the lower intermediate, light red the higher intermediate, and dark red the highest category. The project-specific threshold categories used for the study do not represent or take the place of seafood consumption advisory screening levels (human health) or shellfish health thresholds. Clustered sites use proportionally sized symbols based on the number of sites and/or visits included and changes dynamically with the map scale. Values shown within a circle represent the average concentration from all survey data available for a site cluster. Within each cluster summary, individual site location and contaminant data can be explored for a survey year (select browse features).
Most of the sites of concern for PCBs occur within the , mainly along the shoreline of the Seattle area ( and ), and , , East , and . However, several other locations have been identified in other areas of Puget Sound (e.g., ).
PAHs
Oil spills in Salmon Bay, Seattle, WA.
What are PAHs?
Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that occur naturally in coal, crude oil, and gasoline. They are also produced by the incomplete combustion of organic matter (e.g., burning oil, gas, wood) and are found in non-combusted fuels.
How do PAHs enter the nearshore?
Contamination by PAHs is ongoing and there is little source control of this pollutant to date. Major pathways of PAHs into the Puget Sound include atmospheric deposition (such as smoke from wood burning stoves); stormwater and surface water runoff (containing tire particles and leaked motor oil); and direct inputs into Puget Sound (including oil leaks and spills from marine vessels and creosote treated wood).
Identifying Local Sites of Concern for PAHs
The adjacent map compares PAH concentrations (ng/g, dry weight) in mussels between individual monitoring sites (zoomed in) or site clusters (aggregated sites, zoomed out) which can be used to identify local sites/areas of concern, or contaminant "hotspots". See above section on PCBs for map interpretation details.
Most of the local sites of concern for PAHs occur within the (marine areas 10 and 11), mainly along the shoreline of the Seattle area (Elliott Bay and Salmon Bay), Sinclair Inlet, Bainbridge Island, Commencement Bay, and Gig Harbor. However, several other locations have been identified in other areas of Puget Sound, primarily along developed shorelines (e.g., ), and near ferry terminals and marinas (e.g., ).
Taking Action
The Washington State Departments of Ecology and Health, along with industry and environmental stakeholders, work to identify and take action against and to phase out the use, release, and exposure to PCBs and PAHs in Washington . Working with partners, Ecology developed chemical action plans for both PCBs and PAHs ( PCB Chemical Action Plan , PAH Chemical Action Plan ) to reduce or eliminate the use of these chemical compounds.
Additionally, WDFW's Mussel Watch program has contributed to the Washington Department of Ecology's biennial Water Quality Assessment required under the federal Clean Water Act . The Assessment places water bodies into one of five categories that describe the quality of the water and status of any needed cleanup. Those waters determined to be impaired and without an existing pollution control program are considered Category 5 and placed on the “303(d) list”. Data from this monitoring program have helped identify several impaired water bodies and more waters of concern (Category 2) due to PCB and PAH contamination. The results of the current Assessment is available through an online search tool or mapping tool, the Water Quality Atlas (search Study ID SAM_MNM and WDFW 11-1916).
Community Science
Community Science Volunteers
Each survey year, more than 150 volunteers and partners collectively spend hundreds of hours working to sort and bag mussels, and deploy and retrieve cages during dark winter nights in sometimes adverse weather conditions. Volunteers transport mussels and equipment throughout Puget Sound, process samples in our Olympia laboratory, and document important data that is used to evaluate chemical contamination. It is a massive effort that wouldn’t be possible without the many volunteers and local interest groups we partner with. The above poem demonstrates the dedication of our volunteers, many of whom return each survey year despite the occasional sideways rain!
Watch the video below to see our Port of Tacoma partners in action and learn about how WA State Mussel Watch data is valued.
WDFW Mussel Watch Port of Tacoma
We are grateful for the support of the many individual citizen science volunteers and volunteer organizations that we work with to make a project of this scale a success!
Volunteers from a wide range of affiliations have supported the WA State Mussel Watch Program. They include volunteers from Penn Cove Shellfish, Whatcom County Marine Resources Committee (MRC), San Juan County MRC, Clallam County MRC, Skagit County MRC, Jefferson County Environmental Health, Port of Tacoma, Port of Seattle, Stillaguamish Tribe, Swinomish Tribe, Samish Indian Nation, Tulalip Tribe, Port Gamble S'Klallam Tribe, Jamestown S'Klallam Tribe, Suquamish Tribe, Squaxin Island Tribe, Lummi Island Heritage Trust, WSU Snohomish County Beach Watchers, WSU Kitsap County Beach Watchers, WSU Island County Beach Watchers, WSU Skagit County Beach Watchers, Nisqually Wildlife Refuge, University of Washington Tacoma, University of Puget Sound, Western Washington University, Washington State University, Evergreen State College, Highline College, Olympic College, Avanti High School, Puget Sound Naval Shipyard, Seattle Aquarium, South Puget Sound Salmon Enhancement Group, Friends of Burley Lagoon, Friends of Skagit Beaches, Friends of the San Juans, Vashon Nature Center, Washington Conservation Corps, Puget Sound Partnership.
We extend a special thank you to the organizations below, who have for multiple survey years supported this program by recruiting and organizing volunteers.
Interested in Volunteering?
WDFW is looking for volunteers to help accomplish biennial Mussel Watch surveys. We can’t do it without you!
Volunteers can register for one or more activities which include:
- Bagging mussels at Penn Cove, Whidbey Island, WA in October.
- Deploying mussels in anti-predator cages to selected sites mainly located throughout Puget Sound during a set of nighttime low tides occurring in November.
- Retrieving the mussel cages during a set of nighttime low tides occurring in late January/early February.
- Processing mussels in the laboratory in Olympia, WA in March/April.
The videos below demonstrate a mussel cage deployment and some of the lab work in action.
Mussel Deployment Demo
MUSSEL COMPOSITE
WDFW will assign volunteers registered for mussel cage deployment and/or retrieval to monitoring locations, provide instructions on how to deploy/retrieve cages, and provide all the necessary equipment. For safety we require at least two people for each site so you may be partnered up with another volunteer. A map of available sites to sign up for will be updated each survey year (example map of 2023/2024 field season sites shown on left).
The 2023/2024 field season is complete. The next field survey begins in fall 2025. Field dates and instructions on how to register will be posted here in July 2025.
Thank you for your interest in supporting this nearshore contaminant monitoring effort. Your help is crucial to the success of this program and we look forward to working with you!
About this story
Biomonitoring of Contaminants in the Puget Sound Nearshore was created by Mariko Langness from the Washington Department of Fish and Wildlife (WDFW) Toxics Biological Observation System (TBiOS) program with input from several TBiOS staff , partners and collaborators. It was created using ArcGIS StoryMaps and ArcGIS online. The majority of field images were provided by project partners, volunteers, and TBiOS staff. Video content was created by Lisa Hoang and Robert Fisk (WDFW-TBiOS staff).
This Story Map is a public service developed and maintained by the Washington State Department of Fish and Wildlife (WDFW). The information contained in this website is for reference and general information purposes only. The WDFW may make changes, updates, corrections and/or improvements on the data, website content, applications and services at any time without notice. It is incumbent upon the user of this website to understand the limitations and proper applications of the information contained in this website. Consultation with the WDFW Toxics Biological Observation System (TBiOS) Team on the use of this information is advised.
The Washington State Mussel Watch Program is managed by biologists Mariko Langness and Danielle Nordstrom from the WDFW-TBiOS team,
Mariko Langness is a Senior Biologist with the Washington Department of Fish and Wildlife’s Toxics Biological Observation System (TBiOS) team. Since 2015, she has worked on TBiOS studies monitoring toxic contaminants in marine and salmonid species living in the Salish Sea waters of Washington state. Mariko’s work is focused on monitoring toxic contaminants in nearshore habitats using transplanted bay mussels under the Washington State Mussel Watch Program. She coordinates this collaborative program, working with a wide network of federal, state and local agencies, tribes, and community science volunteers. Mariko has a B.Sc. degree in Aquatic and Fishery Sciences from the University of Washington (2008).
Danielle Nordstrom is a biologist who has been with WDFW since 2016. She first joined the agency within the Salmon and Steelhead Management team tracking commercial salmon and halibut catch data. In 2017, she added to her duties by joining the TBiOS team to provide support to research studies and long-term monitoring for toxic contaminants in Puget Sound biota. She contributes to a variety of laboratory and fieldwork projects as well as environmental education and community outreach. Since 2021, Danielle has coordinated field and laboratory efforts for WA State Mussel Watch surveys where she works with numerous landowners, volunteers, and science partners. Danielle received her B.Sc. in 2015 from The Evergreen State College with an emphasis on marine biology and botany.
