The Environmental Public Health Program routinely evaluates whether lead contamination will impact human health. Currently, one lead exposure model is primarily used for this type of evaluation in residential scenarios, the EPA’s Integrated Exposure Uptake Biokinetic (IEUBK) Model for Lead in Children. This model has limitations. For example, the model is not designed to evaluate acute or intermittent lead exposures and is designed only to assess children ages 6 months to 7 years. For adults and children with short term or intermittent exposure to lead, no model currently exists to evaluate health risk from lead. ATSDR assisted the EPHP with one of their projects by conducting an exploratory analysis of data from one of the EPHP’s sites using the EPA’s beta version of the All-Ages Lead Model (AALM), a lead model currently under development and not being used for site assessments or regulatory purposes. This model can be used to simulate lead exposure for all ages and all exposure scenarios.
METHODS:
We compared results from data from one of our health consultations run through the IEUBK model and through the AALM. We used the default parameters except for site specific soil lead concentrations for the IEUBK model and default parameters, while also accounting for snow cover for part of the year and site specific soil lead levels in the AALM.The IEUBK model did not modify soil concentrations to account for seasonal snow cover.
RESULTS:
Preliminary results from the AALM suggested less risk from the lead exposure scenario than the IEUBK model. However, varying assumptions in each model affected the outcomes.
CONCLUSIONS:
An all ages lead model capable of simulating a variety of exposure scenarios is needed to assess health risks of lead contamination in the environment. Comparison of the two models in one case illustrates that the ability to account for different exposure scenarios can impact the predicted level of risk. Projects in locations that may have scenarios where exposure is limited due to environmental conditions (e.g., snow covering the ground for part of the year) or in which people are exposed to lead for a short time period or intermittently would benefit from an alternative to the IEUBK model.