• PB-TK model/s for inter-species extrapolation of avian exposure and tissue dosimetry 
data consistent with PB-TD models (project B3). 
• Models for bioaccumulation and metabolism of PAHs by fish during ELSs (project B4). 
Approaches for evaluating, at different spatial scales, the cumulative risks from toxic chemicals 
on populations of aquatic life and aquatic-dependent wildlife relative to risks from nonchemical 
stressors (APG 5): 
• Methods for assessing spatial and temporal distributions of risks (project B3). 
• Population models that predict the relative risks of multiple stressors, including toxics 
and habitat alteration, to piscivorous birds (project B3). 
• Methods for assessing PAH risks to feral fish populations with emphasis on vulnerability 
of fish during early life stages to photo-induced PAH toxicity (project B4). 
While integrating new capabilities into the PBT framework, this project will include expansion 
and generalb^tion of the models and methods across chemicals, phyla, and effects to the extent 
possible and scientifically defensible in order to provide site-specific applicability with minimum 
data sets. Scopes of products from this project are therefore subject to the degree of success in 
research fix)m the other PBT projects. Much of this work will be pursued in collaboration with 
OW efforts to update WQC guidelines, and the specific nature and time line of products will be 
developed as part of this collaboration. 
Products 
FY02 Journal article describing a conceptual model for relating risk-based critical residue values 
in fish and wildlife to chemical concentrations in sediment and water (with context of site- 
specific risk-based WQC and assessments of ecological risks associated with contaminated 
s^iments) (Part of APM lA [GPRA # 167]). 
APM lA (GPRA # 167) FY02 Report on integrated water and sediment quality criteria methods 
for assessing site-specific risks of persistent bioaccumulative toxicants to aquatic species (MED). 
Benefits of Products 
This framework will provide guidance for development and application of WQC for protection 
of fish and wildlife populations on the basis of PBT residue-based toxicity data. The framework 
will allow presently available chemical mass balance models to link site-specific chemical 
loading, fate, and transport information to toxicity risks, including population level impacts. 
This, and the demonstration of capability for risk assessment of complex mixtures of PBTs 
having a common mechanism of toxicity, should allow EPA, the States, and Tribes to more 
effectively determine where and to what extent loadings of PBTs to aquatic ecosystems pose 
unacceptable ecological risks. 
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