Ecosystems: Chemical Contaminants in Oysters and Mussels

NOAA’s Mussel Watch Program – the longest running pollutant monitoring program for coastal waters in the United States – analyzes chemical pollutant trends in oysters and mussels. The program includes over 300 sites with data from half of the sites collected every other year.  Since these stationary organisms eat by filtering particles from the water, chemical contaminant levels in their tissues are often a good indicator of local contamination.


Contaminants monitored by NOAA in mussel and oyster populations residing in U.S. coastal and estuarine waters.

Source: NOAA, 2010a


Industrial chemicals commercially available in the United States.

Source: U.S. GAO, 2009


Approximate number of commercially available chemicals in the U.S for which toxicity information exists.

Source: U.S. GAO, 2009


Approximate number of new chemicals introduced into U.S. commerce annually.

Source: U.S. GAO, 2009

Alternative content

Get Adobe Flash player

Download Contaminants in Estuarine Shellfish Interactive Map and Data (2.7mb)

Source: NOAA's Center for Coastal Monitoring and Assessment: Mussel Watch Database.
Note: American Samoa, Guam, Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands are not included in this database.

About this Topic

Data from NOAA’s Mussel Watch Program are provided in this topic to show the locations and concentrations of several chemical contaminants found accumulated in the tissues of estuarine oysters and mussels in coastal waters of the U.S during the time period 1986 to 2009. These contaminants include arsenic, cadmium, chlordane, chromium, DDT, dieldrin, lead, mercury, mirex, nickel, and PCBs. Since 1986, seven chemical contaminants have been found to exceed the FDA Action Level threshold: arsenic in two locations in the southeast in 1989, cadmium in 1989 in the Chesapeake Bay and Lake Pontchartrain in 1991; chromium in 2003 in Narragansett Bay, 2004 in Hudson/Raritan Estuary, and 2005 in Lake Ontario; lead every year (except 1990, 1996, 2003, 2005 and 2007) in numerous locations; mercury in the Hudson/Raritan Estuary in 1988 and 1989; mirex in 1990 in Pamlico Sound and Charleston Harbor and 1991 in Puget Sound; PCB in 1989 in Buzzards Bay. Two Case Studies are presented for this topic: Fire Retardants Emerge as Contaminants of Concern in U.S. and NOAA Scientists Putting Gulf Coast Oysters to the Test. Additionally, there is a Management Success story on Monitoring the Coast: NOAA Mussel Watch.

Closer Look

Relevant Links

NOAA's National Centers for Coastal Ocean Science - Center for Coastal Monitoring and Assessment

Integrated Risk Information System (IRIS), U.S. Environmental Protection Agency

Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services