NCASI's Evaluation of Simple Bioaccumulation Models Using Historical Monitoring Data, 1994 Environmental Conference Proceedings

Steven W. Hinton, Joan D. Abbott, Nancy R. Bartlett

The predictive capabilities of two simple bioaccumulation models were evaluated by comparing model predictions of 2,3,7,8-TCDD fish tissue concentration which were estimated from the observed 104-mill study effluent and receiving water conditions to the tissue concentrations observed during the National Bioaccumulation Study fish survey. One model utilized the widely-recognized bioaccumulation factor (BAF) while the other utilized the biota to suspended sediment accumulation factor (BSSAF) recently proposed by US EPA. In contrast to the BAF modeling approach which assumes fish tissue concentrations are directly related to a fluid-based instream chemical concentration, the BSSAF modeling approach assumes that fish tissue concentrations are proportional to the amount of chemical sorbed to the carbonaceous portion of suspended solids present in the effluent and receiving water mixture. For the data sets used in the evaluation, the BSSAF modeling approach was found to be less predictive than the BAF modeling approach. Given that the BSSAF modeling approach is more complex due to the additional terms needed to quantify the amount of carbonaceous solids present, further evaluation of this approach is needed before it can be considered reliable for predictive purposes.