Working with stakeholders, the Toxic Contaminants Workgroup determined its research agenda should address the following issues: supplying information related to the safe consumption of fish and shellfish; understanding the influence of contaminants degrading the health and contributing to the mortality of fish and wildlife; documenting the sources, occurrence and transport of contaminants in different landscapes; providing science to help mitigate contaminants and emphasize the co-benefits of nutrient and sediment reductions; and gathering information on issues of emerging concern. Our understanding of each of these issues differs.
Issue: Supplying information related to the safe consumption of fish and shellfish.
- 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. Work related to the Toxic Contaminants Policy and Prevention outcome will address PCBs, while recently passed air emission controls will address mercury.
- The Chesapeake Bay Program has developed an infographic that illustrates the importance of following fish consumption advisories, and has worked with the Anacostia Riverkeeper and Anacostia Watershed Society to provide fishing and cooking demonstrations to underserved communities. Learning how to prepare properly trimmed fillets allows people to more safely consume locally caught fish.
Issue: Understanding the influence of contaminants degrading the health and contributing to the mortality of fish and wildlife.
- Research strongly suggests the influence of toxic contaminants on numerous indicators of reduced fish health (e.g., skin and liver tumors, intersex and other gonadal abnormalities, high parasite loads and opportunistic infectious diseases) and occurrences of fish kills throughout the watershed.
- Research has linked toxic contaminants to intersex conditions in smallmouth and largemouth bass, reduced reproductive success in yellow perch and an increase in infectious diseases and parasites that cause fish kills.
- Research from the U.S. Fish and Wildlife Service indicates the presence of tumors in brown bullhead catfish in the Anacostia and Potomac rivers—caused by exposure to sediments contaminated with PAHs and other chemicals—has decreased. The presence of tumors in these fish is still significantly higher than in fish collected from rural areas in the Chesapeake Bay. The role of contaminants in the health of birds, reptiles and amphibians is not as well documented.
Issue: Documenting the sources, occurrence and transport of contaminants in different landscapes. This approach is focused on those settings in which mitigation is expected to have the maximum impact on fish and opportunities to collectively address contaminants, nutrients, and sediment exist. These settings include urban and suburban areas, as well as agricultural lands.
- A technical report shows PCBs and mercury are particularly problematic in the region, and are considered widespread in severity and extent. Polycyclic aromatic hydrocarbons (PAHs) and some herbicides are also considered widespread in extent, while dioxins, petroleum hydrocarbons, some chlorinated insecticides and some metals occur locally. Information is insufficient to determine the extent of biogenic hormones, household and personal care products, pharmaceuticals or flame retardants.
Issue: Providing science to help Chesapeake Bay Program partners identify and prioritize options to mitigate contaminants and achieve co-benefits alongside nutrient and sediment reductions.
- Because PCBs and mercury are widespread in extent and severity and cause fish consumption advisories, options to mitigate these contaminants are being addressed first.
Issue: Gathering information on issues of emerging concern.
- Issues of concern include the effects of microplastics; harmful algal blooms and their associated toxins; the potential effects of poly- and perflouroalkyls (PFASs); coal ash reuse, and the effects of road salts.