Figure 1. Fecal Coliform in Puget Sound 1998-2005

Figure 2. FPI Score by Sampling Station

Figure 3. Puget Sound Beaches Closed to Shellfishing

Figures:  
• Figure 1. Fecal Coliform in Puget Sound 1998-2005  – 
• Figure 2. FPI Score by Sampling Station  – 
• Figure 3. Puget Sound Beaches Closed to Shellfishing

Data Discussion

The Indicator Defined

Acreage of shellfish growing areas that had closures due to bacteria levels

Data Interpretation/Evaluation

According to the U.S. Environmental Protection Agency (EPA), approximately 30,000 acres of commercial shellfish growing areas have been closed to harvest since 1980 due to pollution. Between 1995 and 2004, approximately 4,600 acres of growing areas were closed to commercial harvest, and 12,400 acres were opened to commercial harvest, resulting in a net increase of approximately 7,800 acres opened for commercial harvest in the past decade.

The Washington State Department of Health (DOH) monitors water quality and classifies shellfish areas based on 1) the presence of pollution sources such as sewage systems or treatment plants, 2) levels of fecal coliform bacteria in marine waters, and 3) an analysis of how weather conditions, tides, and currents may affect the distribution of pollutants in the area.  The DOH also performs regular testing for marine biotoxins that may pose a hazard to human health, and will require emergency beach closures when biotoxins are at harmful levels. 

In 2005, the DOH evaluated trends in fecal coliform impacts on shellfish areas throughout Puget Sound.  Fecal coliform levels were measured and assessed using the Fecal Pollution Index (FPI),  a unitless number that ranges from 1.0 (negligible impact) to 3.0 (highest impact).  Fecal coliform impacts in Puget Sound as a whole has remained relatively low since 1998 (Figure 1).  The majority (67%) of stations sampled showed minimal impact due to fecal pollution (Figure 2). Only four areas - Drayton Harbor, Port Susan, Padilla Bay, and Fiduci Bay -  showed moderate impacts, and no areas showed high impacts due to fecal coliform pollution.

The DOH provides an online interactive mapping tool that shows the status of shellfish growing areas.  Maps are updated as beach statuses change due to the result of routine tests for pollutants and biotoxins.  An example of these maps is shown in Figure 3, which shows the status of Puget Sound shellfish harvest areas on October 4, 2008.  The interactive mapping tool for monitored beaches in Puget Sound is available by following the link below.

Data Source and Limitations

These data are compiled by Sustainable Seattle and are the latest summary data published for this indicator.  Trends may have changed since 2005 due to changes in land use, testing protocols, etc.  Raw data from 2007 monitoring for all monitored stations in Washington state are available through DOH at the link below.

US EPA Shellfish webpage for the Puget Sound Georgia Basin Ecosystem can be accessed at http://www.epa.gov/r10earth/psgb/indicators/shellfish/

Washington State Department of Health, Recreational Shellfish Program can be accessed at http://www.doh.wa.gov/ehp/sf/recshell.htm

Atlas of Fecal Coliform Pollution in Puget Sound: Year 2005 (DOH 2007).  Available online at http://www.doh.wa.gov/ehp/sf/Pubs/fecalreport.pdf

Washington State Department of Health online mapping tool can be accessed at http://ww4.doh.wa.gov/scripts/esrimap.dll?name=bioview&Cmd=Map&Step=1

collapse all