A Summary Of Status And Trends In Concentrations Of Selected Chemical Contaminants And Measures Of Biological Stress In San Francisco Bay

Abstract

An assessment of the status and trends in concentrations of selected chemical contaminants (Hg. Cd, Cu, Pb, Cr, Ag, PAH, DDT, and PCB) and biological stress measures in San Francisco Bay was performed as part of the National Status and Trends Program of the National Oceanic and Atmospheric Administration (NOAA). The objectives of the assessment were to: identify observable geographic and temporal trends in contaminant concentrations and the prevalence of biological stress measures, based on historic data; relate selected measures of biological stress to contaminant concentrations; and compare recent measurements made by NOAA in San Francisco Bay to the available historic data. The data utilized in the assessment covered a time period of over twenty years (1964-1986), and was derived from numerous sowces including federal, state and local agencies, universities, consulting f i i , and refereed literature. Initially, individual data sets were examined, utilizing statistical analyses when appropriate, to identify trends or to determine relationships between biological stress measures and contaminant concentrations. The data sets were then p l e d and cautiously examined to see if a preponderance of evidence supported the trends and relationships suggested by the individual data sets. Most contaminants indicated a trend of higher concentrations of toxicants in peripheral harbors and waterways than in the basins of the Bay. Although the available data for most measures of contamination or effects did not indicate any long-term trends, they do suggest the possible recent decrease in Cd, DDT and PCB concentrations. Only the sediment bioassay data showed a clear relationship between contaminant concentrations and bioeffects, however, because the sediments often contained high concentrations of many contaminants only rarely could the results be correlated with a specific contaminant. Overall, the recent NOM-generated data were similar to the historical data.