All-Ages Lead Model (AALM), Version 2.0 (External Review Draft, 2019)

The All Ages Lead Model (AALM) predicts lead concentration in body tissues and organs of hypothetical individuals, based on a simulated lifetime of lead exposure. The purpose of the model is to provide risk assessors and researchers with a tool for rapidly evaluating the impact of possible sources of lead in a specific human setting where there is a concern for potential or real human exposure to lead.

The AALM is an outgrowth of the Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children. Version 0.99d of the IEUBK was released in 1994 and has been widely accepted in the risk assessment community as a tool for implementing the site-specific risk assessment process when the issue is childhood lead exposure. The IEUBK model was designed to assess changes in blood lead of children over periods of no less than a month. It was identified that there was a need to expand the model to include adult exposure and to add several features not available with the IEUBK model.

EPA’s Office of Research and Development has led efforts to create and develop the AALM. The AALM Version 1.05 was reviewed by a SAB panel in October 2005. Based on the findings of the 2005 SAB Review, the 2019 AALM Version 2.0 extends the EPA’s modeling capabilities to estimate lead in blood and other tissues following acute exposures and transiently reoccurring exposures, as well as chronic exposures for individuals between zero and 90 years of age.

The AALM documentation consists of a user-guide and a technical support document, which details all model parameters, equations, and evaluations of model performance. The AALM v 2.0 software was tested on personal computers having a 64-bit Windows 10 operating system. Together, the model software and documentation advance EPA’s earlier modeling capabilities for the assessment of lead exposures on body burden of lead and associated lead biomarkers.

Impact/Purpose

The All Ages Lead Modeling tool was developed to rapidly evaluating the impact of lead exposures on lead levels in blood and other human tissues across mutliple lifestages (from birth to 90 years of age). This 2019 update is highly anticipated since the 2005 update received comments from SAB. Together, the model software and documentation advance EPA’s earlier modeling capabilities for the assessment of lead exposures on body burden of lead and associated lead biomarkers.

Status

Following the SAB Review of the draft assessment, EPA will address comments and release the final report and modeling tool on the EPA website.

Citation

U.S. EPA. All-Ages Lead Model (AALM), Version 2.0 (External Review Draft, 2019). U.S. Environmental Protection Agency, Washington, DC, 2019.

History/Chronology

DateDescription
Dec 1994EPA released the Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children (Version 0.99d).
Sep 2005EPA released the draft report for a 30-day public review and comment period. [Federal Register Notice Sep 27, 2005]
Oct 2005EPA's Science Advisory Board (SAB) hosted a public meeting to discuss the draft report. [Federal Register Notice Oct 14, 2005]
Nov 2005EPA extended the public comment period on the draft report to December 12, 2005. [Federal Register Notice Nov 3, 2005]
Sep 2019EPA released an updated external review draft, version 2 and updated user guide for FORTRAN.[Federal Register Notice Sep 24, 2019]
Oct 2019EPA's Science Advisory Board (SAB) held a 2-day public meeting to conduct a peer review the EPA's AALM External Review Draft Version 2.0, comprising the model's software, technical documentation, and user manual (hereafter referred to collectively as AALM 2.0).
Aug 2020EPA's SAB released the final peer review report from the public meeting and comments.

Additional Information

The All-Ages Lead Model (AALM), Version 2.0, includes an update of the software and updated external review draft technical document that are under review from the EPA Science Advisory Board (SAB). For more information related to the peer reviewer of this modeling tool, please visit the SAB website.

Docket

Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2005-0026