Toxic Contaminants Research

Recent Progress: Increase

Through collaboration with stakeholders and the incorporation of local Total Maximum Daily Load pollutant limits into stormwater permits, the Toxic Contaminants Workgroup has made progress in addressing the impacts of mercury across the watershed and other contaminants of interest in local areas. Regional characterizations improved for agricultural chemicals in the Potomac and Susquehanna watersheds, for PCBs related to restoration efforts in the Anacostia watershed, and for complex mixtures of contaminants in the Shenandoah watershed. The workgroup has also improved our understanding of the reduction of specific contaminants in response to some management actions, but further progress will require additional pollutant removal efficiency studies for stormwater best management practices.

Outlook: On Course

The Toxic Contaminants Research Outcome is on course. Through cross-workgroup collaboration, the Toxics Contaminants workgroup (TCW) has made significant progress on characterizing the occurrence, concentrations, sources and effects of mercury, PCBs and polyfluoroalkyl substances (PFAS). This progress includes the completion of a major Scientific and Technical Advisory Committee (STAC) workshop on polyfluoroalkyl substances (PFAS), as well as four meetings per year dedicated to PFAS and a series of national PCB conferences. Further projects are underway to characterize more regional occurrences and concentrations of other contaminants, such as pesticides, which are the focus of an annual conference facilitated by the workgroup. While this outcome lacks specific metrics for assessing progress, the increased understanding of the impacts and mitigation of a variety of toxic contaminants, along with established plans for further research, synthesis and information sharing, positions this outcome as on course.

Research Issues Status

The TCW used the baseline understanding of environmental contaminants in the Chesapeake Bay watershed to develop a research agenda organized around the following five issues:

Issue: Synthesis of scientific information to make fish and shellfish safer for human consumption.

• Most of the fish consumption advisories issued in the watershed are caused by polychlorinated biphenyls (PCBs) and/or mercury. These pollutants can come from legacy deposits, ongoing inputs and ongoing releases. A 2022 Scientific and Technical Advisory Committee (STAC) workshop identified additional research needs related to developing fish consumption advisories related to per- and polyfluoroalkyl substances (PFAS) in the watershed, which was the focus of a TCW meeting in 2023.

Issue: Understanding the influence of contaminants in degrading the health and contributing to the mortality of fish and wildlife.

• In urban areas, previous studies indicated fish exhibited abnormal tissue growth and reduced reproductive success in the presence of toxic contaminants. The results of a multi-year study on the influence of factors including endocrine-disrupting compounds were synthesized and published. In the Potomac and Susquehanna basins, studies are also addressing the complex interactions of chemical contaminants, pathogens, parasites and other factors contributing to fish mortality.

Issue: Documenting the sources, occurrence and transport of contaminants in different landscape settings.

• This research aids assessment of potential effects on fish and other organism, as well as the options for strategic management. Ongoing research is addressing the important link between the sources, occurrence and transport of these contaminants in different landscape settings The U.S. Geological Survey (USGS) is compiling information on ongoing data collection efforts for PFAS in various media to address needs identified in the 2023 STAC report.

Issue: Synthesis and promotion of science to help mitigate contaminants and emphasize the co-benefits with nutrients and sediment reductions.

• Investigation into the potential co-benefits of best management practices (BMPs) including both agricultural and urban landscapes were completed. Site comparisons between treated (with BMPs) and untreated agricultural and urbanized watersheds, wastewater treatment plants and combined sewer overflows were used to assess nutrient management techniques as a potential strategy to reduce estrogens in environmental waters. A study examining the ability to detect regional temporal trends in river contaminant concentrations within the Chesapeake Bay watershed as a result of BMP implementation was completed.

Issue: Gathering information on issues of emerging concern.

• TCW prioritized PFAS, microplastics and the effects of chloride (road salt) within the watershed. In 2022, the workgroup held a STAC workshop on these topics and published a workshop report in 2023. In 2023, the workgroup dedicated a third of its meeting time to PFAS in an effort to integrate PFAS-related science needs into the other issues. Quarterly meeting topics can be found on the TCW groups page under Projects and Resources.

Learn About Factors Influencing Progress

To achieve this outcome, Chesapeake Bay Program partners have committed to:

• Synthesizing scientific information to make fish and shellfish safer for human consumption.
• Understanding the influence of contaminants degrading the health, and contributing to mortality, of fish and wildlife.
• Documenting the sources, occurrence and transport of contaminants in different landscape settings.
• Synthesizing and promoting science to help mitigate contaminants and emphasize the co-benefits with nutrients and sediment reductions.
• Gathering information on issues of emerging concern.

The research outcome does not have quantitative measures of progress, but two supporting items in the outcome provide a qualitative assessment of recent progress: further characterization of the occurrence, concentrations, sources and effects of mercury, polychlorinated biphenyls (PCBs) and other contaminants of emerging and widespread concern; and identification of which BMPs might provide multiple benefits of reducing nutrient and sediment pollution as well as toxic contaminants in waterways.

As part of the Chesapeake Bay Program’s partnership-wide implementation of adaptive management, progress toward this outcome was reviewed and discussed by the Management Board in September of 2022. It will be reviewed and discussed by the Management Board again in August of 2024.

Download Management Strategy (.pdf)

Chesapeake Bay Program partners have committed to taking a series of specific actions that will support the management approaches listed above.

Ongoing

• Working in the Susquehanna and Potomac watersheds, generating information to document fish health in the watershed.
• Monitoring levels of PCBs in fish and shellfish and moving contaminated sites toward cleanup.
• Better defining the sources of PCBs, including those on land, through stormwater and through atmospheric deposition.
• Considering the developing of a PCB mass balance model for the Chesapeake Bay.
• Better defining the sources and occurrence of endocrine disruptors and other contaminant groups affecting the health of fish and wildlife in the watershed.
• Better defining the potential impacts of unconventional oil and gas activities.
• Generating information on mercury in order to determine whether regional strategies are needed to supplement national efforts to reduce its impact on fish and associated consumption advisories.
• Developing approaches to assess the relative risk of contaminants to help inform policy and prevention strategies.
• Sharing approaches for assessing relative risk with the TCW so the workgroup can consider options for mitigating contaminant impacts.

Learn About Logic & Action Plan

The Water Quality Goal Implementation Team leads the effort to achieve this outcome.

Participating partners include:

• Delaware Department of Natural Resources and Environmental Control (State of Delaware)
• Maryland Department of the Environment (State of Maryland)
• Maryland Department of Natural Resources (State of Maryland)
• University of Maryland, Baltimore County (State of Maryland)
• New York Department of Environmental Conservation (State of New York)
• Pennsylvania Department of Environmental Protection (Commonwealth of Pennsylvania)
• Virginia Department of Environmental Quality (Commonwealth of Virginia)
• Virginia Institute of Marine Science (Commonwealth of Virginia)
• Virginia Polytechnic Institute and State University (Commonwealth of Virginia)
• West Virginia Department of Environmental Protection (State of West Virginia)
• Department of Energy and Environment (District of Columbia)
• Chesapeake Bay Commission
• National Oceanic and Atmospheric Administration
• U.S. Department of Homeland Security
• U.S. Environmental Protection Agency
• U.S. Fish and Wildlife Service
• U.S. Geological Survey
• Bluewater Baltimore
• Maryland Pesticide Network
• Metropolitan Washington Council of Governments