Session 3: PFAS in Aquatic Environments

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All Day Session – 8:30AM-10:30AM and 1:30PM-4:00PM
Howard Room, First Floor, North Wing

  • Drinking Water Operators: Four Training Contact Hours (TCH) are available for this session from the Maine CDC Drinking Water Program. Sign-up sheets are located in the session room.
  • Wastewater Operators: Four Training Contact Hours (TCH) are available for this session through Maine’s Wastewater Operator Certification Program. Sign-up sheets are located in the session room.

Session Co-chairs
Breana Bennett, Maine Center for Disease Control and Prevention
Tom Danielson, Maine Department of Environmental Protection

Per and Polyfluoroalkyl Substances (PFAS) are persistent, toxic chemicals that have been found in many parts of Maine. PFAS can enter aquatic environments through a variety of pathways. Different kinds of PFAS vary in where they can be found in aquatic resources and how much they bioaccumulate in aquatic life. This session will present results and perspectives of how widespread PFAS contamination is in aquatic resources, which kinds of PFAS are most common in aquatic resources, and potential threats to human health and aquatic life.

Session Schedule

Morning Session

Afternoon Session

8:30AM – 8:55AM

Fish Tissue PFAS Concentrations in Wild and Hatchery Fish

Jerrod Parker
Maine Department of Inland Fisheries and Wildlife

To better understand Per-and Polyfluorinated Substances (PFAS) concentrations of fish throughout Maine, the Maine Department of Inland Fisheries and Wildlife (MDIFW) undertook a statewide study in 2022. From February 2022 through June of 2023 MDIFW collected 1,090 fish for PFAS testing. These fish represented 16 species and one hybrid obtained from eight state hatcheries, 38 lakes, and one river distributed throughout the state. Samples were combined into 117 species-location specific composite muscle tissue samples and tested for 28 PFAS analytes. Lab testing failed to detect 17 of the 28 analytes across samples. No PFAS analytes were detected in seven of eight hatcheries, and low concentrations (~0.5 ng/g) of only one analyte were detected in the remaining hatchery. No perfluorooctane sulfonic acid (PFOS) concentrations triggered consumption advisories. PFAS, especially PFOS, concentrations were notably different among species with warm-water species tending to have higher levels. PFAS concentrations were lowest in the long-lived Lake Whitefish (Coregonus clupeaformis). Discrepancies were found between composites composed of the same species within a waterbody. In conclusion, the samples indicate PFAS from fish consumption by the angling public likely poses a minimal health risk given our current understanding, and further studies are needed to determine what factors are driving PFAS bioaccumulation in fish.

9:00AM – 9:25AM

PFAS: A New Fish Tissue Issue

Tom Danielson
Maine Department of Environmental Protection

The Maine Department of Environmental Protection collected fish from lakes and rivers across Maine since 2014 to determine the extent and severity of contamination of per- and polyfluoroalkyl substances (PFAS). The most common PFAS in fish tissue were perfluorooctane sulfonate (PFOS) and long-chain perfluoroalkyl carboxylic acids, such as perfluorodecanoic acid (PFDA). Long-chain PFAS bioaccumulate in fish, often reaching hundreds to thousands times higher concentrations in the fish tissue than the water. Fish with the highest concentrations of PFOS were from waterbodies that were close to potential pathways of contamination, such as aqueous firefighting foam and biosolids from certain wastewater treatment plants spread on farm fields. Maine has a fish tissue action level for PFOS of 3.5 micrograms per gram (µg/g wet weight), which is equivalent to parts per billion (ppb). When average PFOS concentrations in fish samples from a waterbody exceed 3.5 ppb, the Maine Center for Disease Control and Prevention (MeCDC) may consider issuing a fish consumption advisory for PFAS. In addition to the statewide monitoring effort, a joint study was conducted with MeCDC and the Maine Department of Inland Fisheries and Wildlife to determine accumulation of PFOS in stocked brook trout. Hatchery raised brook trout were put in two ponds with very high concentrations of PFOS in the water (>500 ng/L). The brook trout in the two ponds quickly accumulated PFOS and exceeded the fish tissue action level in a week.  

9:30AM – 9:55AM

Surface Water and Fish Impacted by Historic Land Application of Biosolids and Resulting Fish Consumption Advisories in Fairfield, Maine

Breana Bennett (1), Tom Danielson (2), Chris Evans (2), Andrew Smith (1)

  1. Maine Center for Disease Control, Augusta, ME
  2. Maine Department of Environmental Protection, Augusta, ME

An investigation into the presence of PFAS in the Fairfield area of Maine began after PFOS was detected at greater than 20,000 ppt in milk samples collected at a local dairy farm. Testing of soils from farm fields with a history of land application of biosolids identified field average PFOS levels ranging from low 10s ppb to greater than 1000 ppb on a dry weight basis. The headwaters of Fish Brook run near and adjacent to these farm fields that have elevated PFOS levels in the soil. Surface water samples from Fish Brook collected where the stream runs adjacent to fields as well as downstream of the farm fields had PFOS levels measured at 128 – 394 ppt. Brook trout in the headwaters were found to have tissue levels of PFOS ranging from 151 – 162 ppb.  Sampling of brook trout, largemouth bass, and yellow perch in downstream waters of Fish Brook were found to have tissue levels of PFOS ranging from 182– 742 ppb. Fish Brook is a tributary for Messalonskee Stream and elevated of PFOS in tissue were found for northern pike and smallmouth bass from these waters (12 – 57 ppb). This presentation will discuss the data on soils, surface waters, fish tissue, and the subsequent development of site-specific fish consumption advisories.

10:00AM – 10:25AM

Understanding PFAS Variability in Fishes

Christina Murphy

U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit; Department of Wildlife, Fisheries, and Conservation Biology, University of Maine

PFAS compounds are of increasing human health and environmental concern. Even with guidance, variability exists in current fish collection methods, sample sizes, species, and waterbodies sampled within and outside of Maine. Age, sex, size, metabolic rate, and other characteristics may influence PFAS accumulation for individual fish. The PFAS compounds in water responsible for accumulation in fish may also change seasonality with variability in hydrological conditions. Questions remain on how this variability, variability within a species and variability across species impacts assimilation and sample results in Maine fishes, especially as these samples are typically composites. To tackle these uncertainties and improve sampling regimes, we are working to compile existing literature, including data from Maine, to evaluate variability across these axes and to model discriminatory power. This review will guide targeted data collections addressing the most critical aspects of variability with the goal of addressing uncertainties and identifying future sampling designs.


PFAS Monitoring in Tissues of Marine Biota in Maine: Spatial and Ecological Patterns

James Stahlnecker
Maine Dept. of Environmental Protection

The Maine Dept. of Environmental Protection monitors toxic compounds in aquatic environments in part through the Surface Water Ambient Toxics (SWAT) Monitoring Program. Since PFAS monitoring in marine biota was initiated in 2013, blue mussel, softshell clam, American oyster, and lobster tissues have been analyzed. Perfluorooctane sulfonate (PFOS) concentrations in bivalve tissues are typically non-detect or, in a few instances, just exceed reporting limits. PFOS concentrations in lobster muscle tissue are just above reporting limits west of Penobscot Bay and non-detectable in most sites on the eastern coast. PFAS analyses of finfish have included examination of tissue from harbor pollock, striped bass, bluefish, Atlantic silverside, and banded killifish. PFOS concentrations in finfish tissues are higher than in shellfish tissues, with concentrations ranging from 0.15 to 25 ng/g wet weight depending on species and location. PFOS concentrations are higher in upstream sites and diminish toward the marine terminus of estuaries. Spatial distribution of PFOS in estuarine/marine finfish tissue indicates highest concentrations occur near known sources in rivers or upper estuaries. In addition to PFOS, as many as ten different PFAS compounds (from a list of 40 for which testing is directed) are detected at low concentrations in a subset of tissues analyzed across shellfish and finfish species. Perfluorooctanoic acid (PFOA) was not detected in lobster muscle tissue but was present at low concentrations in silverside tissue in the Kennebec estuary only.


Intraspecific and Spatial Variability of PFAS Concentrations in Predatory Waterbirds

Micah Miller, Christopher R. DeSorbo, Lucas Savoy, Helen Yurek, Emily Fellows, Chris Persico, Logan Route, & David Evers

Biodiversity Research Institute

Predatory birds commonly accumulate contaminants via diet and can serve as bioindicators for other taxa, including humans. We surveyed PFAS concentrations in blood plasma of three predatory, water-associated bird species across Maine in 2015-2023: Common Loons, Bald Eagles, and Osprey. For most individuals, PFOS was the dominant PFAS compound, comprising 25-76% of total PFAS burdens. Adults had greater PFOS concentrations than young. Concentrations in avian young were much greater than concentrations in human children; for example, unfledged Common Loons 4-10 weeks of age had 22.6 ± 17 ng/g PFOS versus 2.7-4.2 ng/g in children. We also observed high spatial variability and covariation in concentrations of all PFAS compounds, with high concentrations in eagles and loons sampled in the same waterbody; for example, some of the greatest blood plasma concentrations of PFOS were from Lovejoy Pond in Albion (a known PFAS-contaminated site per Maine Center for Disease Control) for both eagle chicks and adult loons. Given that concentrations in avian blood are orders of magnitude greater than those in humans, and spatial patterns may overwhelm species-level differences, we suggest that: a) a broader sample of birds should be measured for PFAS compounds and related to diets and trophic status of various taxa to identify food web pathways of PFAS exposure in wildlife, and b) water-associated birds accumulate very high blood plasma concentrations of PFOS (and other PFAS compounds we will present), presumably through piscivorous diets, suggesting fish-heavy diets may result in high accumulation of PFAS compounds. 

2:30PM – 3:00PM

Afternoon Break – Auditorium

3:00PM – 3:25PM

PFAS at Maine Landfills

Michael O’Connor
Maine Department of Environmental Protection

In July 2021, LD1600, An Act to Investigate Perfluoroalkyl and Polyfluoroalkyl Substance Contamination of Land and Groundwater was enacted in Maine. The law required licensed landfills with leachate-collecting systems to test leachate for per- and polyfluoroalkyl substances (PFAS) biannually (spring and fall) from Fall 2021 through Fall 2023. Additionally, the Maine Department of Environmental Protection (MEDEP) has investigated a sub-set of the 400+ closed municipal solid waste (MSW) landfills throughout the state to characterize PFAS contamination in groundwater at monitoring wells and nearby private water supply wells. Landfills with leachate collection systems primarily transport leachate to municipal or industrial wastewater treatment plants (WWTP), which ultimately discharge into surface water bodies. PFAS-contaminated groundwater from unlined MSW landfills can also discharge into nearby surface water bodies depending on landfill location and hydrology. This presentation will summarize PFAS results for Maine landfills and discuss the implications for aquatic environments.

3:30PM – 3:55PM

Communicating PFAS Contamination Using Graph-Based Geovisualizations and Summaries

Katrina Schweikert (1) (student), Torsten Hahmann (1), Shirly Stephen (2)

  1. University of Maine 
  2. University of Santa Barbara

PFAs contamination in Maine is reported in numerous disparate data sources including sample results, locations of potential sources and environmental transport information. These datasets come from different agencies at the state and federal level, but their heterogeneity makes it challenging to build a holistic picture of what is known about PFAs contamination and which locations still need further study. 

Knowledge Graphs (KGs) are a special type of information system that link heterogeneous data together and align them to a common ontology or taxonomy of concepts. We construct a KG that combines sample data from Maine Dept. of Environmental Protection (DEP) Environmental and Geographic Analysis Database (EGAD) and the federal Water Quality Portal with information on potential sources, and the properties of vulnerable sites, including private well attributes from Maine Geological Survey (MGS) wells data. We also include chemical information and consider environmental fate and transport of different contamination mechanisms. We then demonstrate how KG queries and tools can be leveraged, for example, to construct interactive maps that aggregate known contamination and potential risk to private well water supply and surface waters statewide and make the information accessible to lay users and experts alike. While the graph is currently still being expanded, these statewide summaries showcase the graph’s analytic and visualization capabilities. Once completed, the KG will integrate data on PFAs contamination around the country to answer questions about where there is risk, where more testing is needed, and what patterns we can learn from the existing sampling data.

About the Session Chairs

Tom Danielson leads the monitoring and assessment of PFAS and other toxics in fish, water, and sediment samples collected from Maine’s lakes, streams, and rivers. Tom coordinates with the Maine Center for Disease Control and Prevention staff, which issues fish consumption advisories when necessary. Tom earned a Ph.D. in Ecology and Environmental Sciences from the University of Maine, a Master of Environmental Management from Duke University, a Master of Public Policy from Duke University, a B.S. in Wildlife Biology from the University of Massachusetts, and a B.B.A in Finance from the University of Massachusetts.