Per- and polyfluoroalkyl substances (PFAS) are now widespread environmental contaminants. PFAS can bioaccumulate and biomagnify and have been linked to potential health effects in humans. In Alaska, salmon are a concern because they represent an important commercial stock and subsistence fishery for indigenous communities. This study will assess PFAS in salmon species and rainbow trout from remote and urban areas in the region to understand the prevalence of PFAS in fisheries and possible pathways of introduction.
Why We Care
Per- and polyfluoroalkyl substances (PFAS) have been manufactured since the 1940s and are widely used in industrial and commercial products. PFAS are commonly referred to as “forever chemicals” because they can last a long time in the environment, with some estimated to take over 1,000 years to degrade in nature. Certain PFAS have been linked to reproductive, developmental, and immunological effects in humans and animals, and they have been shown to bioaccumulate and biomagnify in marine food webs. Given their persistence in the environment and their possible detrimental effects, there is a need to determine their presence in coastal environments and valuable fisheries.
Salmon in Alaska are important commercial, recreational, and subsistence fisheries, and the North Pacific Fisheries Management Council (NPFMC) is concerned about the possible presence of PFAS in salmon and the effects that these substances may have on fishery stability and ecosystem health. Further, little is known about the extent and variability of PFAS presence across different coastal areas (e.g., urban vs. remote areas) and the sources of environmental introduction (e.g., open water coastal vs. terrestrial inputs). Therefore, preliminary research is needed to establish priority areas for management and environmental assessments.
What We Are Doing
Since 2021, this ongoing project has sampled five different salmon species (Chinook, pink, sockeye, chum, and coho) of varying life stages (smolt, juvenile, adult) and origins (wild vs. hatchery) from both urban (Auke Creek in Juneau), and remote (Little Port Walter Research Station on Baranof Island) areas, in addition to wild freshwater juvenile rainbow trout to investigate the presence and pathways of PFAS across these coastal systems. Water, sediment, and fish feed samples have also been collected. The study aims to better understand how PFAS accumulate in various tissues of different salmon species and rainbow trout over time and across space, help understand how PFAS move through the food web, and investigate possible pathways of introduction into the environment. Our results will be relevant to stakeholders in Alaska and the Pacific Northwest, including indigenous communities, fisheries and habitat managers, and seafood consumers.
This joint effort with NOAA Fisheries, based out of NOAA’s Little Port Walter Research Station on Baranof Island, is generating foundational information to better understand the presence of PFAS in fisheries and coastal areas. Over the course of the study, 145 individual fishes have been sampled, and muscle, liver, kidney, gonad tissues, and blood have been analyzed for 40 different PFAS. Through analysis of these different tissues, water, sediment, and fish feed, the project aims to understand if PFAS exposure is predominantly marine and coastal, freshwater or terrestrial, influenced by a disparate diet, or if there is a widespread source of exposure, such as broad-scale atmospheric deposition. Ultimately, the project will use this robust framework to better understand sources, pathways, and implications of PFAS exposure across Alaska’s coastal systems.
What We Found
Preliminary results have demonstrated the presence of PFAS across all of the salmon species and coastal areas currently assessed. PFOS, which is one of the compounds with current EPA drinking water guidelines, was the most frequently detected compound. Overall, 24 different PFAS compounds out of the 28 assessed thus far have been identified in these salmon tissues.
Benefits of Our Work
Guided by stakeholder needs, this project has been carefully designed to deliver the most applicable and actionable data for management of these important fisheries and identification of priority areas for future research. The NPFMC, Tribal communities, Alaska’s commercial salmon hatcheries, and recreational fisheries managers will be able to use the results and information on PFAS exposure for facilitation of current and future efforts.
Next Steps
NCCOS and NOAA Fisheries will continue evaluating PFAS exposure in salmon and rainbow trout populations to answer the project’s key questions: where are PFAS, how did they get there, and what are the management implications. Researchers will complete chemical analysis and data interpretation for product dissemination via technical reports, peer-reviewed manuscripts, and participation at symposiums and conferences in 2026 and 2027.