250-8 Raised Bed(s) No Lead: Re-Designing Residential Lead Soil Interventions Through Community Based Research, Geochemistry, and Urban Agriculture

Session: Deliver the Message: Harness Diverse Media and Divergent Methods to Describe and Depict Geoscience Information

Presenting Author:

Authors:

Abstract:

Urban gardening lead (Pb) risk reduction best practices need refining to embrace the emerging knowledge on Pb geomobility and center community expertise. Our case study on Pb exposure in a Boston residential backyard explores modifying existing low cost interventions (e.g raised beds) to ameliorate soil splash as a significant transport mechanism for mobilizing lead.

For the last 15 years, our lab–guided by the principles of participatory action research–has co-developed an annual Pb and soils student workshop with The Food Project, a non-profit in Boston focused on building food security to address environmental injustice. As an element of this workshop, students bring in soil samples from locations that matter to them, and a field portable X-Ray Fluorescence (fp-XRF) scan of over 37,000 μg/g from one sample prompted us to conduct extensive follow-up. We used a fp-XRF and a benchtop XEPOS XRF spectrometer, transect sampling, GIS mapping, SEM imaging, and an experimental raised bed design, to understand the geochemical fingerprints, hot spots, and mechanisms of deposition and migration of Pb in urban soils. Average [Pb] in dripline-influenced soil (0-150 cm from house foundation) were 460% higher than in non-dripline-influenced soils (330 cm- end of transect). [Pb] as a function of grain size and SEM imaging suggest dual pathways of Pb transport to the soil, through physical paint chips and paint dissolution. We estimate that Pb recontaminates raised beds (height = 5 cm) through particle resuspension at a rate of approximately 5,000 μg/year. This value will vary depending on ambient soil physical characteristics and the percent of bare soil present in the yard. Blending geochemistry with community-based research, our work demonstrates an innovative approach to the ubiquitous issue of soil Pb contamination, holding the potential to inspire new community-driven risk-reduction measures that combine several best practices to minimize raised bed lead recontamination.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7992

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