Long-term bioaccumulation monitoring with transplanted bivalves in the SanFrancisco Estuary

The California State Mussel Watch and the Regional Monitoring Program for T race Substances have conducted biomonitoring for trace elements and organic contaminants in the San Francisco Estuary using transplanted bivalves (Myt ilus californianus, Crassostrea gigas, and Corbicula fluminea). Significant declines (p < 0.01) in contaminant concentrations in M. californianus for the period 1980-1996 were observed for PCBs, p,p'-DDE, cis-chlordane, dield rin, and Ag, while a significant increase was observed far Cr (p < 0.05). C ertain limitations of the "mussel watch" approach are illustrated by examin ing data on survival, body condition, and contaminant uptake, including the inability of the technique to predict accumulation of mercury and selenium at higher trophic levels in the ecosystem, These results indicate that bio monitoring using transplanted bivalves, when part of a consistently support ed long-term program, can produce valuable data on the spatially and tempor ally averaged abundance and distribution of certain contaminants in coastal ecosystems, (C) 1999 Elsevier Science Ltd. All rights reserved.