The ICRP age-specific biokinetic model for lead: Validations, empirical comparisons, and explorations

The objective of this manuscript is to provide a description of the Interna tional Commission for Radiation Protection (ICRP) model and a comparison to other models (the integrated exposure uptake biokinetic [IEUBK] and O'Flah erty models), including the software used with the models, and a comparison of the model predictions for selected situations. The ICRP biokinetic mode l for Pb is a multicompartmental model for Pb uptake and disposition in chi ldren and in adults. The model describes deposition and retention of absorb ed Pb in numerous tissues, removal from tissues to plasma, and movement alo ng various routes of excretion. Long-term skeletal behavior of Pb is descri bed in terms of age-specific rates of restructuring of compact and trabecul ar bone. The ICRP model is more flexible and has wider applicability than t he IEUBK model. The major disadvantages are that application of the compute r model requires some basic computer skills, and the user must convert the Pb concentrations in food, air, soil, dust, paint, or other media to the am ount oi Pb ingested or inhaled per day. Direct comparisons between the ICRP model and the IEUBK model are provided by modeling blood Pb levels using t he IEUBK v0.99d default Pb uptakes and intake values. The model is used to simulate occupational exposure cases and a controlled Pb inhalation experim ent in adult humans. Finally, use of the model to explore situations with l imited data is illustrated by simulating the kinetics and disposition of Pb during acute Pb poisoning and chelation therapy in a child.