Open-File Report 02-453
NEAR FIELD RECEIVING WATER MONITORING OF TRACE METALS IN CLAMS (MACOMA BALTHICA) AND SEDIMENTS NEAR THE PALO ALTO WATER QUALITY CONTROL PLANT IN SOUTH SAN FRANCISCO BAY, CALIFORNIA: 1999-2001
report presents trace element concentrations analyzed on samples of fine-grained
sediments and clams (Macoma balthica) collected from a mudflat one kilometer
south of the discharge of the Palo Alto Regional Water Quality Control
Plant in South San Francisco Bay. This report serves as a continuation
of the Near Field Receiving Water Monitoring Study which was started in
1994. The data for 1999-2001 are interpreted within that context. Generally,
metal concentrations in both sediments and clam tissue samples have been
within the range of values produced by seasonal variability. Copper and
zinc, however, display a continued decrease, recording the lowest winter
maxima concentrations in both sediment and tissue samples in 2001. Yearly
average of bioavailable copper, zinc and silver concentrations in 1999-2001
are some of the lowest recorded since monitoring began in 1975. A slight
increase in mercury in sediments and selenium in tissue in early 2001 are
also observed. These enrichments are believed to be mainly caused by hydrogeologic
processes affecting the area although only continued sampling will confirm
whether anthropogenic sources influence the concentrations of these elements.
This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.
the Report (PDF, 1.6 MB)
Link to Appendix 1 & 2 (raw data)
Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.
Send questions or comments about this report to Stacey Andrews (firstname.lastname@example.org) (650) 329-4468
For more information about USGS activities concerning Ecology and Contaminants in San Francisco Bay, visit the USGS Ecology and Contaminants Website.
|AccessibilityFOIAPrivacyPolicies and Notices|
|U.S. Department of the Interior, U.S. Geological Survey
Persistent URL: http://pubs.water.usgs.gov/ofr02453
Page Contact Information: GS Pubs Web Contact
Last modified: Friday, January 11 2013, 03:23:36 AM