SS4.03 Factors Controlling the Bioavailability and Bioaccumulation of Inorganic and Organic Chemicals into Aquatic Food Chains
Date: Friday, June 14, 2002
Time: 10:15:00 AM
Location: Carson B
 
GriscomSB, Stony Brook University, Stony Brook, USA, sbgriscom@yahoo.com
Fisher, N, S, Stony Brook University, Stony Brook, USA, nfisher@notes.cc.sunysb.edu
Luoma, S, N, US Geological Survey, Menlo Park, USA, snluoma@usgs.gov
 
KINETIC MODELING OF METAL ACCUMULATION IN THE CLAM, MACOMA BALTHICA: QUANTIFYING FOOD AND DISSOLVED SOURCES
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A biokinetic model was used to understand and predict Ag, Cd, and Co concentrations in the facultative deposit-feeding clam, Macoma balthica living in San Francisco Bay. Model parameters included laboratory-derived uptake and loss rate constants from food, overlying water, and porewater, and field measurements of metal concentrations in food (sediment and phytoplankton) and water. We compared metal accumulation by clams that were assumed to be surface deposit-feeding (SDF) with those that were filter-feeding (FF). Considering uptake from food and all dissolved sources, the model-predicted metal concentrations were comparable to concentrations in field-collected clams. Thus, the parameters derived experimentally appear applicable to field conditions and the model accounts for the major processes governing metal concentrations in clams. Ingested sediment was shown to be a major source for Cd and Ag but Co accumulation was only from the dissolved phase. Comparison of model-predicted metal concentrations in SDF and FF clams with measured concentrations in field populations indicates that clams in San Francisco Bay are essentially in SDF mode.