A lifetime physiologically based pharmacokinetic model for CB 153 in harbour porpoises: in silico tool for predicting concentrations of future lipophilic pollutants

Physiologically based pharmacokinetic (PBPK) models are mathematical models which are largely based upon the physiological characteristics of the species and upon the biochemical properties of the selected chemical. They give important information about the kinetics and bioaccumulation of pollutants inside the body. As such, they can have a great predictive value and they can be of major importance for risk assessment of chemicals in marine mammals. In the present study, a preliminary PBPK model was developed for the most persistent andprevalent polychlorinated biphenyl (CB 153) in order to find out more about its bioaccumulation, distribution and kinetics in several tissues of harbour porpoises (Phocoena phocoena). The model consists of 4 compartments, namely liver (metabolism), blubber or adipose tissue (storage), kidney, and brain (neurotoxicity) and was developed using Berkeley Madonna software. All physiological/biochemical parameters were found inthe literature. This PBPK model is capable of simulating the bioaccumulation of CB 153 during the entire life span of approximately 20 years of the harbour porpoises. The intake of CB 153 was from milk from birth to 6 months and after weaning, principally from fish as a food source. The model was evaluated using existing datasets from the literature and data from own analyses performed with GC-MS. Preliminary computer simulation results were consistent with the available data. It is believed that a well constructed PBPK model is a good reflection of reality and that the model can be used as a non-invasive and non-destructive tool for predicting pollution in harbour porpoises or perhaps in marine mammals in general