Children's lead exposure in the U.S.: Application of a national-scale, probabilistic aggregate model with a focus on residential soil and dust lead (Pb) scenarios
Citation:
Zartarian, V., J. Xue, E. Gibb-Snyder, J. Frank, R. Tornero-Velez, AND L. Stanek. Children's lead exposure in the U.S.: Application of a national-scale, probabilistic aggregate model with a focus on residential soil and dust lead (Pb) scenarios. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 905:167132, (2023). https://doi.org/10.1016/j.scitotenv.2023.167132
Impact/Purpose:
Although great strides have been made to reduce children's exposure to lead (Pb) in the United States many individuals are still exposed to lead from multiple sources, and disproportionately impacted communities remain (U.S. EPA, 2022; President's Task Force on Environmental Health Risks and Safety Risks to Children, 2018). Ingestion of Pb-contaminated dust and soil continues to be an important contributor to children's blood lead levels (BLLs) because of legacy sources (e.g., Pb in paint, leaded gasoline) and on-going uses (e.g., leaded aviation fuel, consumer products) (Frank et al., 2019; US EPA, 2023a). Pb exposure can cause a range of health effects; one of particular concern is nervous system effects in children, specifically cognitive decrements and issues with attention, impulsivity, and hyperactivity (U.S. EPA, 2023a). There is no evidence for a threshold for cognitive effects in children (AAP, 2016; CDC, 2022a; U.S. EPA, 2023a).
Description:
Lead (Pb) exposures from soil and dust ingestion contribute to children's blood lead levels (BLLs) in the United States. The U.S. Environmental Protection Agency (EPA)'s Strategy to Reduce Lead Exposures and Disparities in U.S. Communities and the Federal Action Plan to Reduce Childhood Lead Exposure describe multi-pronged collaborative approaches. These include reducing multi-media lead exposures nationally using analytical tools such as EPA's Stochastic Human Exposure and Dose Simulation model for lead [SHEDS-Pb; formerly known as SHEDS-IEUBK (Integrated Exposure Uptake Biokinetic model)], which was initially developed and applied with a focus on children's drinking water exposures. In this study we applied SHEDS-Pb to determine what residential soil Pb and dust Pb concentrations (individually and their sum) can keep BLLs of potentially exposed young children in the general U.S. population below specified values, considering aggregate exposures from water, soil, dust, food, and air. We considered two age groups (1 to <2 years and 2 to <6 years), two BLL values (5 μg/dL and 3.5 μg/dL), and two population percentiles (95th and 97.5th). Sensitivity analyses were conducted using several alternative model inputs and data sets, yielding 15 scenarios summarized in the paper. Of those scenarios, we focused on ones with the most recent science and available data. Modeled soil Pb concentrations by age group, population percentile and reference BLL scenarios for the focus scenarios ranged from 70 ppm to 220 ppm; and modeled dust Pb concentrations ranged from 110 ppm to 240 ppm. These results are consistent with current soil and dust Pb concentrations in the U.S. general population and are lower than most of the current U.S. Federal standards. Estimated BLLs compared well with measured BLLs from CDC's NHANES 2009–2016 (0–27 % relative error for focus scenarios). This analysis can be used to inform EPA and other federal Pb efforts.
URLs/Downloads:
DOI: Children's lead exposure in the U.S.: Application of a national-scale, probabilistic aggregate model with a focus on residential soil and dust lead (Pb) scenarios