TOXICOLOGICAL FOUNDATIONS OF ECOLOGICAL RISK ASSESSMENT - BIOMARKER DEVELOPMENT AND INTERPRETATION BASED ON LABORATORY AND WILDLIFE SPECIES

Ecological risk assessments based on chemical residue analysis and spe cies demographics tend to ignore the bioavailibility and bioaccumulati on of the chemicals of concern. This study describes the incorporation of mechanistically based biomarkers into an ecological risk assessmen t of a polycyclic aromatic hydrocarbon (PAH)contaminated site. A combi nation of soil residue analysis, tissue residue analysis, biomarkers i n on-site trapped animals and biomarkers in animals confined to enclos ures was used. In particular, the use of captured deer mice (Peromyscu s maniculatus) for these studies is compared to the use of laboratory- raised deer mice placed in enclosures. This study indicates that the h igher degree of variability in the responses of wild deer mice make th e use of enclosure studies advantageous. Positive control studies perf ormed by dosing laboratory-raised deer mice with the same PAHs as roun d on the site were used to validate this approach. These studies indic ate that immune suppression occurred at PAH concentrations an order of magnitude below those required for the induction of ethoxyresorulin-O -dealkylase activity.