NOAA’s National Mussel Watch Program (MWP) has published three technical memorandums to summarize results of contaminants of emerging concern (CECs), trace metals, and legacy organic contaminants from their 2021 comprehensive surveys of the Mid-Atlantic. These technical memorandums capture the team’s findings from sampled mussels and oysters at 45 different sites along the east coast, from Massachusetts to North Carolina.
NOAA’s MWP plays a critical role in delivering early-warning contaminant intelligence, supporting ecosystem health assessments, and helping safeguard coastal communities that depend on clean waters and healthy marine resources. The 2021 surveys further strengthen nearly four decades of continuous, nationally consistent coastal contaminant monitoring. Such long-term, standardized assessment of toxic chemicals is essential for detecting emerging contamination threats, tracking spatial and temporal trends, and informing science-based management actions that protect both ecosystem integrity and human health.
To execute this survey, NCCOS researchers partnered with a broad network of local collaborators, including nonprofits, academic institutions, and state agencies to collect bivalves from sites of local and regional importance. As sentinel species (used to detect risk to humans), mussels and oysters integrate contaminant exposure over time, providing a robust and cost-effective means of detecting toxic chemicals before adverse impacts become widespread.
The team analyzed the collected bivalves for nearly 600 chemical compounds, many of which are environmentally persistent and known to pose risks to marine organisms and humans who consume seafood. The results, summarized in three technical memorandums, reinforce the MWP’s unique role in generating actionable contaminant data to support early warning, ecosystem health evaluations, and the protection of coastal and human health.
The first, an assessment of contaminants of emerging concern (CECs), compiled data for 223 different compounds, including PFAS and pharmaceuticals, finding that 96 percent of sites had at least one detected contaminant. The two most commonly detected PFAS compounds on the Mid-Atlantic Coast in 2021 were PFOA and PFOS, which are two of the EPA PFAS compounds with drinking water regulations. With the exception of antibiotic prescription drugs, which were sparsely detected in both mussels and oysters, pharmaceutical and personal care products were generally more frequently detected in mussels than they were in oysters on the Mid-Atlantic Coast in 2021.
The second was an assessment of trace metals that synthesized data across 14 different elements, finding that cadmium, silver, and tin were the most commonly detected compounds. Many metals, including cadmium, copper, nickel, silver, and zinc exhibited a similar geographic trend along the Mid-Atlantic Coast, wherein concentrations decreased moving outwards towards the mouths of both the Delaware and Chesapeake Bays. Species of bivalves have differing affinities for certain metals, which can be seen within the data from this 2021 survey. Specifically, lead often exhibits higher concentrations in mussels than in oysters, whereas copper, silver, and zinc exhibit higher concentrations in oysters than in mussels.
The third, an assessment of legacy organic contaminants, assessed 11 different classes of compounds, finding that the contaminants were uniformly detected and at generally low concentrations. However, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have persisted at levels above the EPA subsistence fishers values at a large portion of sites assessed in 2021.
The information presented within the technical memorandums will prove useful for regional managers as they assess contaminant trends over time and at the identified locations.
Partners in this effort: Buzzards Bay Coalition, University of Rhode Island, Hudson River Foundation, Billion Oyster Project, New York Department of Environmental Conservation, New Jersey Department of Environmental Protection, Maryland Department of Environment, Virginia Marine Resources Commission, Virginia Institute of Marine Science, University of North Carolina Wilmington.
Administered by NCCOS, the Mussel Watch program was initiated in response to a legislative directive under Section 202, Title II of the Marine Protection, Research and Sanctuaries Act (MPRSA) (33 USC 1442), which mandated the Secretary of Commerce to implement a long-term national water quality monitoring initiative.