Edward Moon, Carlos Primo C. David, Samuel N. Luoma, Daniel J. Cain, Michelle I. Hornberger and Irene R. Lavigne
U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 03-339, 2003
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This 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 2002, herein, are interpreted within that context. Metal concentrations in both sediments and clam tissue samples have been within the range of values produced by seasonal variability. However, copper and zinc, display continued decreases. Copper in sediment was observed to drop below the ERL (Effects Range-Low) concentration for the third consecutive year and zinc concentrations never exceeded the ERL. Yearly average concentrations of copper, zinc and silver in Macoma balthica for 2002 are some of the lowest recorded since monitoring began in 1975. Mercury and selenium concentrations in sediments and clams at Palo Alto were similar concentrations observed elsewhere in the San Francisco Bay.
Abstract
Introduction
Purpose
Study Site
Methods
Sediment
Clams
Metals Analysis
Results and Discussion
Salinity
Sediments
Clams 1
Conclusion
References
Figures
Tables
Appendix A.
Appendix B.
Appendix C.
Appendix D.
Appendix E.
Appendix F.
For additional information write to:
Samuel N. Luoma,
U.S. Geological Survey, MS 465
345 Middlefield Road
Menlo Park, CA 94025
Copies of this report may be obtained from the authors or:
U.S. Geological Survey Information Center
Box 25286, MS 517
Denver Federal Center
Denver, CO 80225
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