Dead fish sits on napkin before before disected.
Researchers are studying the varying levels of forever chemicals present in different species. In one study of smallmouth bass, four PFAS chemicals were detected in every specimen analyzed. (Photo by Will Parson/Chesapeake Bay Program)

In the Chesapeake Bay watershed, studies surrounding the toxic chemical group known as PFAS, short for per- and polyfluoroalkyl substances, have been focused mostly on how they impact drinking water—and for good reason.

PFAS is a class of over 12,000 chemicals used in a variety of products to make them resistant to heat, oil and water, such as non-stick frying pans, food wrappers, clothing materials, electrical equipment and flame-retardant foams. The chemicals can enter the environmental in a number of ways—either from the products containing them wearing out or from industrial sites and chemical plants discharging into the water.

Once in the environment, PFAS don’t break down, and instead accumulate in rivers and streams (which is where they get the nickname “forever chemicals”). Long-term exposure to these chemicals can put you at greater risk of cancer, liver problems, thyroid issues, birth defects, kidney disease, decreased immunity and other serious health problems.

While determining the PFAS concentrations in public drinking water around the Chesapeake is critical, scientists in the region are finding that there is a lack of research around how these chemicals impact ecological resources of the Bay, including the ones that end up on our plates.

In a recent workshop, scientists from across the entire Mid-Atlantic were brought together by the

Chesapeake Bay Program’s Toxic Contaminants Workgroup and Science and Technical Advisory Committee (STAC) to improve our understanding of PFAS in the Bay ecosystem. The workshop resulted in a state of the science report that includes a series of recommendations for filling research gaps.

The existing research on PFAS in the Bay ecosystem

Understanding the effects of PFAS on the Bay ecosystem is an issue with multiple variables. What river the chemicals are in, which species are consuming them, where that species is in their life stage and the level of contamination all determine how the fish, shellfish or bivalves are affected.

During the STAC workshop, participants noted the most researchers in the watershed studying PFAS focus on point-source discharge. Industrial sites and military or civilian fire training areas are of particular interest because of the PFAS-containing firefighting foams that have been used in these locations. Only researchers at federal and academic institutions reported studies related to nonpoint PFAS sources, such as stormwater runoff and biosolid land application, which is when organic matter taken from a sewage treatment is used on farms as fertilizer (PFAS is known to accumulate in biosolids). The workshop attendees reported no studies on how PFAS enters the water through septic systems or atmospheric deposition.

When it comes to how PFAS impacts the health of wildlife in the Bay, there was a variety of data presented at the workshop. Heather Walsh, a fish biologist from the United States Geological Survey (USGS), shared findings on PFAS accumulation in blood plasma from smallmouth bass in the Potomac and Susquehanna River watersheds. Four PFAS chemicals were detected in every bass, including PFOS, PFUnA, PFDoA, and PFDA, and concentrations of PFDoA and PFUnA were higher in males than in females. Future studies are being conducted to determine the health effects of PFAS alone and in combination with other factors that have the potential to impact fish health like rising temperatures, increasing nutrients, exposure to other chemicals like pesticides and mercury, and disease.

Two men in protective gear spray white foam outside.
Certain firefighting foams used across the Chesapeake Bay watershed contain PFAS. (Photo by A1C Nathaniel G. Bevier/USAF)

Additionally, Marie DeLorenzo of the National Oceanic and Atmospheric Administration (NOAA) presented on how PFAS accumulates in ocean life, which impacts food chains in the Bay. Preliminary results from NOAA studies indicated that the most sensitive species were larval mud snails, followed by sheepshead minnows, grass shrimp and oysters. Through NOAA’s Mussel Watch Program, the federal agency is monitoring 28 PFAS compounds in sediment and bivalves, helping to develop a national database for PFAS in coastal environments that resource managers can use.

Scientists at the workshop also investigated the question of how much PFAS has already accumulated in the Bay’s wildlife. Since 2020, the Maryland Department of the Environment (MDE) has been studying PFAS occurrence in water, fish tissue and oysters in locations that include the St. Mary’s River, Piscataway Creek and tributaries on Maryland’s Eastern Shore. In fall 2021, MDE began its strategic sampling of fish tissue for PFAS in harbors, bays and metro regions. Data appear to indicate certain PFAS, especially PFOS (a particularly hazardous PFAS chemical that has been voluntarily phased out in the US), have substantial variability between fish species and do not appear to accumulate in certain mollusks and crustaceans. Channel catfish, for example, were found to have significantly less PFAS than largemouth bass, sunfish and perch, but questions on species diet and food chain dynamics exist. To date, PFAS have not been identified in mollusks in the Chesapeake Bay.

Also shared at the workshop was a pilot study from Morgan State University that has the potential to estimate concentrations of PFOS within the Bay’s food chain. Living things throughout the Bay’s trophic structure—the layers of life that exist from the muddy bottom to the surface of the water—all consume PFAS, including plant and algae. As fish consume contaminated plants, and those fish are consumed by other fish, PFAS moves through the food chain, a process known as biomagnification. Researchers at the university are developing a model that allows them to estimate the concentration of PFOS based on where wildlife are located within the trophic structure.

Currently, few fish consumptions specific to PFAS exist within the Chesapeake Bay watershed. In 2021, the Maryland Department of the Environment issued a fish consumption advisory in Piscataway Creek for PFOS contamination in largemouth bass, sunfish and bullhead. At the workshop, Sandra Goodrow of the New Jersey Department of Environmental Protection shared a presentation on the development and application of fish consumption advisories in New Jersey. The information included a brief introduction to the statewide program for fish consumption advisories, which includes statewide, regional and waterbody specific advisories.

A pile of dark black-grey fertilizer sits outside.
Biosolids treatment results in fertilizer at the Richmond Wastewater Treatment Plant in Richmond, Virginia. PFAS is known to cling on to biosolids and remain in fertilizer. (Photo by Will Parson/Chesapeake Bay Program)

Filling in the science gaps

Workshop attendees agreed that more research is needed to understand how PFAS is affecting the Bay ecosystem and what this might mean for our fisheries, specifically. Members identified several science gaps and prioritized them as being a short-term, near-term or long-term priority. These gaps range from information on how PFAS affects fish at different life stages to the chronic toxicity of blue crabs and oysters due to PFAS.

To fill in the needed science gaps, workshop participants identified six actionable recommendations:

  1. Enhance interaction between management agencies and scientists to facilitate broad coordination across the Chesapeake Bay watershed.
  2. Develop data needs for fish consumption advisories collaboratively across jurisdictions.
  3. Consider a monitoring network and uniform approaches to inform PFAS across the Chesapeake Bay watershed.
  4. Prioritize studies designed to address PFAS occurrence and effects in different land-use settings.
  5. Standardize field collection and analytical approaches to better compare data among studies and jurisdictions.
  6. Collect standardized data to develop ecological risk assessments across a range of species for the protection of aquatic resources.

While numerous knowledge gaps exist in regard to PFAS in the Bay ecosystem, STAC members noted that there is a unique opportunity for an integrated approach from researchers across the watershed.

By pooling resources, streamlining research methods and sharing findings, conversation groups within the watershed can tackle this issue and inform policy that will benefit all of those living within the region.



david michael Sutherland

Great overview. As an avid outdoorsman, there are many concerns about how this serious issue is effecting reproduction and general health of our natural resources and people. There are obvious sources of PFAs that can be immediately addressed; can't help but see those sources being overlooked in most reports in the Bay area. The major contributors are Waste water treatment facilities and overflows or raw discharges; Dinali and Synegro being allowed to spread Waste onto farmland on Maryland eastern shore; and leaching landfills. There are technologies and tools available to address these specific sources to at least begin to break a link in the chain. I hope everyone takes this matter seriously because the impacts to the entire health of our ecosystem is real.

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