• Refine BAFs and models to incorporate metabolism in the food chain and to reduce 
uncertainties associated with species, life stages, and effects end points associated with 
ecological risks for PBTs. 
• Provide a bioaccumulation model for complex mixture of PAHs in fish ELSs suitable for 
assessment of risks to feral fish populations to photo-activated toxicity under project B4. 
Scientific Approach 
Bioaccumulation factors, BSAFs, and food chain models incorporate both generic (non-site 
specific) and site specific elements of bioaccumulation science. A conceptual model for 
integrating high quality bioaccumulation monitoring data with mechanistically based food chain 
bioaccumulation models (e.g., Gobas 1993) will be used for advancing and organizing methods 
for linking chemical residue-based effects data to chemical concentrations in water and 
sediments; and then for risk based WQC development, sediment remediation evaluations, and 
aquatic ecological risk assessments in general. These methods are expected to be an evolutionary 
advancement of bioaccumulation methods presently incorporated into EPA’s Great Lakes water 
quality guidance (EPA 1995b), the methodology for deriving ambient WQC for the protection of 
human health (EPA 2000f), and the framework for application of toxicity equivalence 
methodology for polychlorinated dioxins, furans and biphenyls in ecological risk assessment 
(EPA 2002). The research results will be organized to maximize the accuracy for applying 
general bioaccumulation data and models to site-specific assessments with no or minimum data 
collection on site is required. 
1. Field Data Requirements. 
In general, models and tools for extrapolation and/or prediction can be developed only when 
adequate experimental data are available. One of the major objectives of this research plan is to 
develop field data of the appropriate quality and breadth for im{x*oving bioaccumulation models 
and tools. Breadth of field data includes the completeness of the measurements on all 
components of the food web and its surroundings, and the range of properties associated with the 
chemicals of interest. Furthermore, these field measurements must be intrinsically connected so 
that data from each component are reflective of the conditions sensed or felt by the other 
components. Depending on the ecosystem of interest, measurements over time might be 
required. In this research effort, field data will be developed for all analytes using capillary 
column gas chromatograph/mass spectrometry (GC/MS) techniques with stable isotopes and MS 
resolution of 10,000. The use of analytical techniques with these characteristics will reduce 
uncertainties and biases associated with field data, and when used for all environmental 
components, will provide data of comparable quality among all components of the food web and 
its surroundings. 
Initially, a high quality bioaccumulation data set for a four trophic level, mixed benthic/pelagic 
food web from southern Lake Michigan will be developed for PCBs, PAHs, PCDDs, PCDFs, and 
some chlorinated pesticides. This list of analytes might be expanded after the initial analyses for 
other PBTs which have useful properties for development of bioaccumulation models and tools 
(e.g., chemicals with large molecular weights, > 600 amu, or useful metabolism rates in fish). 
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