Jensen, Paul, Holly Chen, Paul Boothe, Charles, Marshall, and Teresa BattenfieldProceedings: The State of the Bay Symposium IV. January 28-29, 19992010-02-152010-02-151999http://hdl.handle.net/1969.3/25818pgs. 37-40Since trace metal standards were developed from laboratory data in the mid-1980s, there has been a continuing challenge in making field observations at concentrations as low as the calculated criteria. Over the years attempts to measure the very low concentrations required have been plagued by analytical difficulties and contamination problems, particularly in dealing with estuarine samples. Because of these problems, historical metals data (data from the 1970s and 80s) have been shown to have major problems, with values orders of magnitude higher than are measured with modern methods. The technology to obtain reliable observations has been slowly evolving over the last decade, and is still relatively costly. As a result, there are still few accurate observations of trace metals that can be reliably compared with ambient criteria. This paper will present the new results of this special sampling and relate the results to available criteria.trace metalsfield measurementscontaminationChapter