Scientific and Technical Advisory Committee

Per- and polyfluoroalkyl substances (PFAS) have been manufactured and used in a variety of industries in the United States since the 1940s. PFAS are ubiquitous and persistent in the environment and have the potential to have adverse human and ecological health effects. There are more than 12,000 unique compounds, making analysis and reporting difficult. A STAC workshop gathered speakers from Chesapeake Bay jurisdictions, federal agencies, and academic institutions, including representatives from across the Nation, to better understand the state of the science, improve science coordination, and propose approaches to improve our knowledge of PFAS. The workshop was designed to (1) summarize current understanding of sources, occurrence, and fate of PFAS, (2) identify current efforts and approaches to inform the potential effects on fish and wildlife, and their consumption by humans, (3) consider study designs, and comparable sampling and analysis methods, for a more coordinated PFAS science effort, (4) determine and prioritize knowledge gaps, and (5) provide actionable scientific recommendations for monitoring and research.

This workshop report summarizes the current understanding of sources, occurrence, and fate of PFAS and identifies on-going efforts and approaches to inform the potential effects on fish and wildlife, and their consumption by humans. The report provides overarching guidance for research and monitoring to address science gaps, foster communication and collaboration, to help stakeholders better coordinate PFAS efforts to ensure data comparability across the entire Chesapeake Bay Watershed. Enhanced coordination among jurisdictions and agencies requires the creation of common study objectives to collect data and information based upon the media being sampled. This strategy could ensure the ability to conduct statistical analysis with “large” pooled data, allowing for a better understanding of PFAS occurrence, fate, transport, and source apportionment within the Bay and across the watershed. With the release of EPA Strategic Roadmap in 2021, the PFAS landscape is rapidly evolving. After the conclusion of the workshop, the EPA released an updated draft Method 1633 for approval and updated interim health advisories (HA’s) for perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorobutane (PFBS) and hexafluoropropylene oxide (HFPO) dimer acid and its ammonium salt (Gen X). Similarly, all guidance and science gaps identified in this report are rapidly evolving and should be reassessed periodically.

Ten science gaps were identified by workshop participants with six overarching actionable recommendations supporting at least one of the science gaps. The science gaps were ranked by need and binned into four categories designed to address data needs on 1) sources, fate, and occurrence more broadly across the watershed, 2) exposure and bioaccumulation across a range of species, 3) fish consumption advisories, and 4) ecological effects across a range of species, PFAS compounds and concentrations.

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As atmospheric temperatures go up, water temperatures have been increasing in the Chesapeake Bay tidal waters and in streams and rivers across the Bay’s watershed. Water temperatures are expected to continue rising, based on climate change projections.

Increases in water temperature have significant ecological implications for Bay and watershed natural resources and could undermine progress toward Chesapeake Bay Program (CBP) partnership goals for fisheries management, habitat restoration, water quality improvements, and protecting healthy watersheds. This STAC workshop examined current information on drivers and effects of rising water temperatures and sought answers to a critical question: what might the CBP partnership do now–within the scope of its current goals, policies and programs–to actively prevent, mitigate or adapt to some of the adverse consequences. Adapting to new water temperature conditions will have effects across the partnership.

Workshop preparation showed, from the outset, that the drivers, effects and likely management implications of water temperature increases are quite different between the Bay and the watershed. Therefore, both workshop days featured concurrent watershed and tidal sessions, and the findings and recommendations in the STAC report are organized in the same way.

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The agricultural sector is a key part of the solution for achieving long-term water quality goals established by the Chesapeake Bay Program (CBP) partnership. Current levels of best management practice (BMP) adoption on agricultural lands are not sufficient to meet pollutant reduction goals across the Chesapeake Bay watershed (CBW). In this workshop, agricultural service providers across public and private sectors were invited to propose and discuss ideas on BMP adoption and implementation garnered from their own experiences.

The main points that emerged from the workshop are: 1) BMP adoption strategies need to be flexible and adaptable to the specific circumstances of individual farm operations (i.e., one size does not fit all), and 2) conservation programs should be designed with outreach needs in mind in order to reach a much broader range of farmers, especially those in critical source areas and those who do not typically seek conservation technical assistance. The recommendations found in this report were formulated by the steering committee based on what was heard over the course of three workshop sessions.

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