The NOAA Mussel Watch Program (MWP) is the longest-running continuous chemical contaminant monitoring program, serving United States coastal and Great Lakes waters since 1986. Today, the program is celebrating 40 years of data collection and analysis.
Since its inception, MWP has successfully documented the decline of legacy pollutants due to improved management, increased regulations and chemical bans. It has served as an invaluable resource for coastal management across the nation.
Building upon the success of the U.S. Environmental Protection Agency’s pilot MWP (1976–1978), which demonstrated that using bivalves could help quantify contaminants entering our coastal ecosystems, NOAA’s MWP was formed to monitor chemical contaminants and biological indicators to establish nationwide baseline contamination levels.
MWP uses a combination of national oversight from NOAA with a network of regional and local collaborators or stakeholders to monitor coastal health throughout the country. The program relies on bivalves, specifically mussels and oysters, to gauge water quality. Because these organisms are sessile, or fixed in one location, and filter large volumes of water, they act as natural monitors that accumulate contaminants in their tissues. This provides scientists with a snapshot of local chemical contamination that reflects ambient water conditions, capturing contamination that may be too diluted to detect in isolated water samples using standard laboratory equipment.
When launched, MWP monitored approximately 145 sites. Today, that network has expanded to over 400 sites across the Atlantic, Pacific, and Gulf Coasts, as well as the Great Lakes and U.S. territories. Over time, the program’s methodology has also evolved to ensure long-term sustainability. Originally, the program sampled all sites on an annual basis. In 1994, it transitioned to biennial sampling, and by 2013, it adopted a more sustainable five-year regional rotating model.
The scope of what the program monitors has also broadened. Originally focused on legacy contaminants like DDT and PCBs, it now screens for over 600 substances, including modern contaminants of emerging concern such as PFAS — substances often referred to as “forever chemicals” — flame retardants, and various pharmaceuticals. The program currently tracks trends for over 150 legacy contaminants and nearly 450 newer chemicals, providing one of the most comprehensive environmental datasets in the world.
While Mussel Watch was designed to establish a long-term baseline rather than assess specific pollution hot spots, its historical data has proven indispensable during environmental crises. When disasters like Hurricane Katrina and the Deepwater Horizon oil spill occurred, the program’s decades of background data provided critical guidance for restoration and impact assessment.
As they look to the future, MWP managers are proactively incorporating adaptive techniques to maintain baseline contaminant data while also addressing emerging threats to best meet end user needs. To learn more, download the MWP 40th Anniversary One Pager for additional program highlights throughout the years. If you’ve been part of our journey, we encourage you to share your research using the hashtag #40YearsofMWP.
Additional Resources:
- The Coastal Pollution Data Explorer is an interactive web-based platform that enables users to explore spatial and temporal trends in chemical contaminant data across U.S. coastal areas. Users can compare, analyze, graph, map, and download contaminant data collected by NCCOS from 1986 to present.
- Mussel Watch Program scientific journal articles and technical reports can be found here.
- Sign up for the MWP biannual newsletter here.
NOAA established the MWP program in response to a legislative mandate under Section 202 of Title II of the Marine Protection, Research and Sanctuaries Act (MPRSA) (33 USC 1442), which called on the Secretary of Commerce to implement a long-term monitoring initiative.
