A U.S. Lead Exposure Hotspots Analysis

To identify U.S. lead exposure risk hotspots, we expanded upon geospatial statistical methods from a published Michigan case study. Evaluation of identified hotspots using six lead indices, based on housing age and sociodemographic data, showed moderate-to-substantial agreement with state-identified higher-risk locations from nine public health department reports (45-78%) and with hotspots of children’s blood lead data from Michigan and Ohio (e.g., Cohen’s kappa scores 0.49-0.63). Applying geospatial cluster analysis and 80th-100th percentile methods to the lead indices, the number of U.S. census tracts ranges from ~8% (intersection of indices) to ~41% (combination of indices). Analyses of the number of children <6 years old living in those census tracts revealed the states (e.g., Illinois, Michigan, New Jersey, New York, Ohio, Pennsylvania, Massachusetts, California, Texas) and counties with highest potential lead exposure risk. Results support use of available lead indices as surrogates to identify locations in the absence of consistent, complete blood lead level (BLL) data across the United States. Ground-truthing with local knowledge, additional BLL data, and environmental data are needed to improve identification and analysis of lead exposure and BLL hotspots for interventions. While the science evolves, these screening results can inform “deeper dive” analyses for targeting lead actions.

Impact/Purpose

The results presented in this paper support the use of available lead indices to identify hotspots in the absence of consistent, complete blood lead surveillance data across the United States. We used census tract level analyses to identify, on a national scale, the states and counties with highest potential lead exposure risk (based on the six indices considered and the number of children younger than six years old living in the identified census tracts). This analysis utilizes peer-reviewed, published methods described in EPA’s 2022 Michigan lead data analysis paper and builds off the 2022 interagency EPA/HUD/CDC lead mapping state-of-science paper. Statistical evaluation of available data indices was conducted in multiple ways: with MI and OH children’s blood lead levels surveillance data and locations identified from nine state health department reports. This science can guide other lead hotspots identification and verification efforts, and inform lead reduction actions through collaborations with state and local health departments. There are a number of limitations of this analysis and opportunities to enhance data and methods for identifying Pb exposure hotspots. While science in this area evolves, these U.S. screening level results identifying states, counties, and census tracts with potential high lead exposure risk can inform further efforts to target lead actions for public health protection. For example, these could include identifying the most disproportionately impacted communities that might be eligible for federal or state lead mitigation programs; determining where resources should be focused to reduce lead-based paint exposures, replace lead service lines, address lead-contaminated soils, and other sources; and assessing additional data needs and priority locations for collecting more environmental and biomonitoring data to identify lead exposure hotspots and their drivers. The analysis presented in this paper advances the science for identifying high lead exposure locations to support U.S. efforts including the Federal Lead Action Plan, EPA Lead Strategy, Biden-Harris Lead Pipe and Paint Action Plan, and Biden-Harris Get the Lead Out Partnership.  

Citation

Zartarian Morrison, V., J. Xue, A. Poulakos, R. Tornero-Velez, L. Stanek, E. Snyder, V. Helms Garrison, K. Egan, AND J. Courtney. A U.S. Lead Exposure Hotspots Analysis. American Chemical Society, Washington, DC, 7(7):3311-3321, (2024). [DOI: 10.1021/acs.est.3c07881]

DOI: A U.S. Lead Exposure Hotspots Analysis