Estimating Childhood Multi-Media Lead Exposure: Expanded Exposure/Uptake/Biokinetic Model

Abstract

Despite significant reductions over the past decade, lead exposure continues to be a problem for millions of children in the US. Minimizing further exposure to lead from its numerous and diverse sources is a priority of various regulatory components of the Environmental Protection Agency (EPA), as well as other Federal and State agencies. A critical step in assessing lead risks is the estimation of childhood lead exposure in the future under alternative regulatory scenarios. Using a wide variety of year- and age-specific data on lead concentrations in multiple media, exposure and activity patterns, absorption rates and biokinetics, an integrated uptake/biokinetic model was developed by EPA in its review of the lead National Ambient Air Quality Standard. The model can estimate blood lead distributions among childhood populations over time. It was validated using measured environmental and blood lead data around a primary lead smelter, and has been successfully applied to other point sources. An enhanced version of the model has been developed to deal with a wider variety of exposure situations, especially those at high levels. A personal computer (PC) compatible version is available for assessments of Superfund sites, paint lead abatement strategies, drinking water contamination and other problems.