The integrated exposure uptake biokinetic model for lead in children: independent validation and verification

The U.S. Environmental Protection Agency employs a model, the integrated exposure biokinetic (IEUBK) model for lead in children, for the assessment of risks to children posed by environmental lead at hazardous waste sites. This paper describes results of an effort to verify the consistency of the documentation with the computer model and to test the computer code using a group that is independent from those involved in the model development. This review concluded that the IEUBK model correctly calculates the equations specified in the IEUBK model theory documentation. However, several issues were identified on model documentation, model performance, and the C++ programming language code (i.e., IEUBK model source code) documentation. These issues affect the ability of an independent reviewer to understand the workings of the IEUBK model but not the model's reliability. As a result of these findings, recommendations have been provided for updating documentation to the model as well as associated adjustments to the model documentation.