(Note: Because of resource reductions after the initial development of this plan, 
the following project will not be pursued at this time.) 
Project Title B2, Incorporate Chemical Metabolism Rates and Site-specific BioavailabUity 
into Bioaccumulation Models Structured for Practical Assessments of Risks to Fish and 
Wildlife Exposed to PBTs 
Project Coordination and Resources (4.0 FTEs: MED-4.0) 
Objectives 
Ecological risk-based criteria for PBTs require a strong capability to relate chemical residue 
based dose-toxicity response data to environmental exposure conditions, and thus to chemical 
loading limitations for protection of vulnerable populations of fish and wildlife. The present 
capability is limited by the amount and quality of data available; significant data gaps (e.g., rates 
of metabolism, bioaccumulation in ELSs); inconsistencies in approaches used for predicting 
bioaccumulation; and uncertainties associated with extrapolation of bioaccumulation data across 
species, life stages, and exposure conditions. This research begins with an objective to develop 
the first data base designed to provide a comprehensive set of BAFs and BSAFs for organisms in 
a complex food web, coupled with bioavailability and metabolism information, so that methods 
for extrapolation of measured BAFs and BSAFs to different ecosystems may be developed and 
validated. The ultimate objective is to extend these models to allow directly application to ELSs 
of fish and wildlife. ELSs are often most sensitive to PBTs, have greatest impact on population 
maintenance, and therefore are risk determining. Specific objectives, associated with 
development and application of the high quality bioaccumulation data base, are: 
• Provide a comprehensive conceptual model for relating risk-based critical residue values 
in fish and wildlife to chemical concentrations in sediment and water. 
• Develop a high quality bioaccumulation data base for a four trophic level, mixed 
benthic/pelagic food web in southern Lake Michigan. 
• Provide a master set of BAFs, BSAFs, and associated bioavailability data with an 
evaluation of procedures for extrapolation to diverse ecosystems and chemical loading 
conditions. 
• Develop guidelines for sampling and analysis of biota, lipid, sediment, water, and organic 
carbon to maximize inter-ecosystem extrapolations and comparisons of bioaccumulation 
data. 
• Determine whole organism based rates of metabolism from the high quality 
bioaccumulation data base for PCBs, PCDDs, PCDFs, PAHs, and other PBTs (as data are 
available). 
113 
