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Users Guide for the All Ages Lead Model (AALM) Version 3.0 - Excel User Interface and Fortran Model Executable (Final Report, 2024)

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Abstract

EPA researchers developed the All Ages Lead Model (AALM) to evaluate the impact of lead exposures on lead levels in humans. It rapidly estimates the effect of exposures on lead concentrations in tissues of children and adults; can assess exposures of a day or more, as well as chronic exposures; and can be applied to specific individuals or to groups of similarly exposed individuals.

The AALM is an outgrowth of the Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK). IEUBK assesses changes in blood lead in groups of children up to 7 years of age, over periods of a month or more. The IEUBK is not intended to predict blood lead in a specific individual. The IEUBK is widely accepted as a tool for implementing the site-specific risk assessment process. The AALM expands that modeling capacity with the goal of reducing uncertainty in lead exposure assessments for adults and children.


About the Model

The Version 3.0 All Ages Lead Model (AALM) rapidly estimates the effect of lead exposures from media such as air, water, food, dust, or soil on lead concentrations in blood, bone, and other human tissues from birth to 90 years of age. The AALM provides significant advancement in EPA’s commitment to provide risk assessors and risk managers with a model to rapidly evaluate the impact of possible sources of lead in specific human exposure scenarios where there is a concern for human exposure to lead.

The AALM is an outgrowth of the Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK) which assesses changes in blood lead in children up to 7 years of age, over periods of no less than a month. The IEUBK is widely accepted in the risk assessment community as a tool for implementing the site-specific risk assessment process to address childhood lead exposure. The AALM expands upon the IEUBK model to include older childhood, adolescents, and adult lead exposure. It allows assessment for intermittent exposures of one day or more, as well as chronic exposures. The AALM can be applied to specific individuals or to groups of similarly exposed individuals.

The AALM includes many customizable features. This software program allows users to input detailed exposure information (e.g., duration of exposure and levels of lead in various media). The model is then run for the specified scenario regime and results (i.e., lead tissue burdens) are returned to the user.

Who Should Use the Tool

The primary audiences for the AALM are organizations and individuals conducting or using human health risk assessments for lead, especially those engaged in site-based risk assessments for lead. These include federal and state agencies, academics, medical and health researchers, public health professionals, industry, and others. For efforts aimed toward reducing human exposure to lead, the model may be useful to help identify the most effective mitigation strategies.

Users need a basic understanding of the pathways by which people are exposed to lead and to be able to convert lead concentrations and intake rates for the various media to those units required for model inputs.

Benefits of Using the Tool

There is no known level of lead exposure without risk. While average blood lead levels in the United States have declined, millions of children and adults are still exposed to various sources of lead. EPA and its federal partners continue to work to reduce lead exposures in communities. EPA and others rely on models to simulate levels of lead in children and adults following exposure, to use in risk assessment and decision making.

The AALM represents a significant advancement in ability to estimate potential effects of lead exposure, with more flexibility in parameters. Extensive technical documentation and user guide provide clear, specific examples with step-by-step instructions for varied exposure scenarios. These important materials help to ensure that users can access and easily use the model, design model scenarios which are most relevant for them, and use model output most accurately and effectively.

Installation and Technical Contact

AALM requires a Microsoft Windows operating system and Microsoft Excel. The AALM v3.0 64-bit executable and the user interface have been most extensively tested on computers having a Windows 11 Enterprise 64-bit operating system with 32 GB RAM, and Microsoft 365 Excel.

How to Install

  • Go to downloads and save all the files to your computer.
  • Then unzip the zip file into a folder on your c:\ drive where you have read/write privileges. Due to security safeguards, the AALM model will typically not run from your PC’s Documents folder or any network drive.
  • After unzipping files, open AALMv3-0_mmddyy.xlsm, where mmddyy should be 030124 or more recent. This is the AALM’s user interface.
  • The first time this file is opened, there may be a red banner under the Excel menu bar reading, “SECURITY RISK Microsoft has blocked macros from running because the source of this file is untrusted.” To resolve this issue, exit Excel. From the File Explorer, right click on AALMv3-0_mmddyy.xlsm and select properties. At the bottom of the file Properties, notice the Security warning. Click on the box by Unblock, then press .
  • The next time the file is opened, there may be a yellow banner under the Excel menu bar reading, “SECURITY WARNING Some active content has been disable.” To resolve this issue, press the button to the right of the warning. The model is now ready to run simulations. You can save different Excel files with a filename of your preference for each of your different simulations.
  • For more details, please see the ReadMe.txt file.

Impact/Purpose

EPA researchers are developing tools to model lead levels in human tissues resulting from lead exposure and are also working to reduce uncertainty in human health risk assessments for adults and children exposed to lead. The All Ages Lead Model (AALM) addresses both goals. 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.

Status

This is the final report.

Citation

U.S. EPA. Users Guide for the All Ages Lead Model (AALM) Version 3.0 - Excel User Interface and Fortran Model Executable (Final Report, 2024). U.S. Environmental Protection Agency, Washington, DC, 2024.

History/Chronology

Date Description
01- Dec 1994 EPA released the Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children (Version 0.99d).
02- Sep 2005 EPA released the draft report for a 30-day public review and comment period. [Federal Register Notice Sep 27, 2005]
03- Oct 2005 EPA's Science Advisory Board (SAB) hosted a public meeting to discuss the draft report. [Federal Register Notice Oct 14, 2005]
04- Nov 2005 EPA extended the public comment period on the draft report to December 12, 2005. [Federal Register Notice Nov 3, 2005]
05- Sep 2019 EPA released an updated external review draft, version 2 and updated user guide for FORTRAN.[Federal Register Notice Sep 24, 2019]
06- Oct 2019 EPA'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).
07- Aug 2020 EPA's SAB released the final peer review report from the public meeting and comments.
08- Apr 2024 EPA released the All Ages Lead Model, Version 3.0 which included the updated model, Users Guide, and Technical Support Document.

Additional Information

Technical Contact

For technical assistance, please contact James Brown: brown.james@epa.gov and/or the EPA Lead Committee hotline pbhelp@epa.gov


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Last updated on October 23, 2024