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Project: Southern California Mussel Watch

Background and Objectives

To characterize the spatial extent and temporal trends in coastal contaminant levels nationwide, NOAA’s National Status and Trends (NS&T) Program has collected and analyzed bivalve species since 1986 as part of their Mussel Watch program. This data set has provided unparalleled information on the declines of biological exposure to contaminants associated with source control and increased effluent treatment over the last 20 years. It has also demonstrated that local hot spots still exist in the southern California and it provides a point of comparison with the rest of the country. Twenty-one open coastal sites in Southern California have been monitored by NS&T since 1986. These sites are visited biannually by project partners to measure levels of trace metal and organic contaminants. In 2007, SCCWRP agreed to sample 13 additional sites added in 2007 to increase spatial coverage, where NOAA will continue to process the samples. A collaborative effort to select priority contaminants of emerging concern (CECs) for future assessment is also planned as a part of this project.

The goals of this study are to:

• Increase spatial and temporal resolution of Mussel Watch data in southern California;
• Provide contaminant data in Areas of Special Biological Significance and Marine Protected Areas
• Compare passive sampling methods with contaminant accumulation in bivalves; and
• Prioritize emerging contaminants for future coastal monitoring and assessment.

Mussel Watch sites in southern California (left); Mussel beds (Mytilus spp.) in the intertidal zone in Santa Barbara County, CA (right).


This project was initiated in 2007 with anticipated completion in 2012.


Collaborating organizations collect bivalves biannually, with NOAA providing analytical measurements in accordance with long-standing program QA/QC guidelines. As an additional sampling technique, passive samplers using solid-phase microextraction (SPME) are being deployed at Mussel Watch sites and analyzed using methods developed by SCCWRP. Both passive samples and bivalves will be analyzed for trace constituents, and data will be compiled and assessed by project participants.

In 2009-10, approximately 70 established NS&T sites in California will be stratified by land use and sampled during the 2009-10 winter season. Passive samplers including SPME, polyethylene, and polar organic compound integrated samplers (POCIS) will be co-deployed at selected sites. Collaborators will analyze these samplers for a large suite of CECs, including pharmaceuticals, household and commercial chemicals, and current use pesticides in both bivalve tissue and passive samplers. Upcoming years will focus on the development and evaluation of bioindicators that characterize integrated exposure to environmental stressors for bivalves and other sentinel coastal species.


Chemistry results are pending from the first cycle of bivalve collection at the expanded list of 34 Southern California sites. Up-to-date results from the parent NOAA NS&T Mussel Watch program can be found on the NOAA website.


National Oceanic and Atmospheric Administration (NOAA)
State Water Resources Control Board (SWRCB)
Multi-Agency Rocky Intertidal Network (MARINe)
San Francisco Estuary Institute (SFEI)
US Geological Survey (USGS)
US Environmental Protection Agency (EPA)


Pilot Monitoring of CECs in California via the Mussel Watch Program (Video) - January 2012 presentation to SCCWRP member agencies on background and preliminary findings from the pilot CEC monitoring effort.

For more information on Southern California Mussel Watch, contact Keith Maruya at (714) 755-3214.
This page was last updated on: 4/17/2012