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Evaluation of the integrated exposure uptake biokinetic (IEUBK) model for lead in children
Citation:
Brown, James. Evaluation of the integrated exposure uptake biokinetic (IEUBK) model for lead in children. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 33:187-197, (2022). https://doi.org/10.1038/s41370-022-00473-2
Impact/Purpose:
The objective of this study was to evaluate performance of the Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK model v2.0) as it would be typically applied at Superfund sites to predict blood Pb levels (BLLs) in populations of children. The IEUBK model was developed by the U.S. Environmental Protection Agency (EPA) to support assessments of health risks to children from lead (Pb) exposures [1,2,3]. The model is currently used in human health risk assessments at sites where Pb is a chemical of potential concern [1, 2]. These sites are regulated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Resource Conservation and Recovery Act (RCRA).
Description:
Background: The Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK model) was developed by the U.S. Environmental Protection Agency to support assessments of health risks to children from exposures to lead (Pb). Objective: This study evaluated performance of IEUBK model (v2.0) as it would be typically applied at Superfund sites to predict blood Pb levels (BLLs) in populations of children. Methods: The model was evaluated by comparing model predictions of BLLs to 1144 observed BLLs in a population of children at the Bunker Hill Superfund Site for which there were paired estimates of environmental Pb concentrations. Results: Predicted population geometric mean (GM) BLLs (GM: 3.4 µg/dL, 95% CI: 3.3, 3.5) were within 0.3 µg/dL of observed (GM: 3.6 µg/dL, 95% CI: 3.5, 3.8). The model predicted the observed age trend in GM BLLs and explained ~90% of the variance in the observed age-stratified GM BLLs. The mean predicted probability of exceeding 5 µg/dL (P5) was 27% (95% CI: 24, 29) and observed P5 was 32% (95% CI: 29, 35), a difference of 5%. Differences between geographic area stratified mean P5 (predicted minus observed) ranged from −11 to 14% (mean difference: 2.3%). Significance: Although the more general applicability of these findings to other populations remains to be determined in future studies, our results support applications of the IEUBK model (v2.0) for informing risk-based decisions regarding remediation of soils and mitigation of exposures at Superfund sites where the majority of the exposure unit GM BLLs are expected to be ≤5 µg/dL and where it is desired to limit the predicted probability of exceeding 5 µg/dL to <5%.
URLs/Downloads:
DOI: Evaluation of the integrated exposure uptake biokinetic (IEUBK) model for lead in children