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EVALUATION OF A FIRST-ORDER MODEL FOR THE PREDICTION OF THE BIOACCUMULATION OF PCBS AND DDT FROM SEDIMENT INTO THE MARINE DEPOSIT-FEEDING CLAM MACOMA NASUTA
Citation:
Boese, B., E. Lee, AND S. Echols. EVALUATION OF A FIRST-ORDER MODEL FOR THE PREDICTION OF THE BIOACCUMULATION OF PCBS AND DDT FROM SEDIMENT INTO THE MARINE DEPOSIT-FEEDING CLAM MACOMA NASUTA. Environmental Toxicology and Chemistry 16(7):1545-1553, (1997).
Description:
A first-order model for predicting contaminant bioaccumulation from sediments into benthic invertebrates was validated using a marine deposit-feeding clam, Macoma nasuta, exposed to polychlorobiphenyl (PCB)-spiked and dichlorodiphenyltrichloroethane (DDT)-contaminated sediments. Contaminant uptake and depuration were analyzed following short-term and long-term sediment exposures. Uptake and depuration rates were used to predict steady-state bioaccumulation factors (BAFs) and exposure times needed to attain steady state. These predicitions were compared to observed steady-state BAFs. Estimating elimination and uptake rates from depuration and short-term uptake experiments was an accurate means of predicting BAFs for some PCBs (log octanol-water partition coefficient, Kow'<7) but was not as accurate for predicting DDT BAFs. The exposure time need to attain steady state was poorly predicted by the model. The results demonstrated that a standard 28-d bioaccumulation test estimated steady-state tissue residues within two-fold and was a better predictor than the model for the BAFs of superlipophilic PCBs (log Kow>7). Differences in contaminant bioavailability were noted between field-contaminated (DDT) and laboratory-spiked (PCB) sediments.