Human health risk assessment of heavy metals in residential soil—Houston, Texas

Human health risk assessment increasingly recognizes the need to integrate participatory-based research, geospatial analysis, and environmental epidemiology, particularly to address contamination concerns in underserved and disadvantaged communities. Here, we demonstrate the combined application of such methods within the Greater Fifth Ward neighborhood in Northeast Houston. In particular, in tandem with community members, we collected soil samples from 193 residential sites using a complete canvassing method from July to November 2021 to characterize contaminant concentrations, focusing on heavy metals and metalloids As, Ba, Cd, Cr, Pb, Se, Ag, and Hg measured using Inductively Coupled Plasma-Mass Spectrometry. Individual heavy metals as well as cumulative cancer and non-cancer risks were calculated for children and adults using the USEPA Regional Soil Screening Levels and benchmarks for specific land uses, such as crop growing. Soils from most sites had low or typical background levels expected in urban areas, but samples from several locations had significantly elevated lead levels (>1200 mg/kg) that warrant additional examination. Geospatial analysis suggested clustering of heavy metal contaminants within one geographic area of the neighborhood. This study highlights how participatory research in underserved environmental justice communities can help characterize current conditions as well as establish priorities for future investigation.