Modeling the toxicokinetics and biomagnification of polychlorinated biphenyls (PCBs) in birds

This thesis provides an examination of the toxicokinetics of polychlorinated biphenyls (PCBs) in birds. Experimental studies documenting the dietary bioavailability, plasma/fat distribution and elimination of individual PCBs were performed in two avian species, ring doves (Steptopelia risoria) and American kestrels (Falco sparverius). The assimilation of PCBs from food was highly efficient, independent of diet properties and weakly dependent on congener hydrophobicity. Blood plasma/fat distribution coefficients were constant with time and dependent on the relative lipid contents of the two tissues. Elimination of PCBs occurred by biotransformation, fecal egestion and egg production pathways and exhibited declining trends with increasing chemical hydrophobicity. For the persistent congeners, PCB elimination rates were regulated mostly by fecal egestion and egg production rather than biotransformation. The above studies were utilized to calibrate an open two compartment rate constant model in each species and to calibrate a fugacity based gastrointestinal absorption model in ring doves.