Temporal and spatial dynamics of post-fire heavy metal contamination in urban areas

Project lead: Frida D. Garcia Ledezma

We seek to understand the long-term environmental and human health impacts of wildfires in the wildland–urban interface (WUI), with a particular focus on the fate and persistence of heavy metals (HMs) in residential soils. Urban-adjacent wildfires release complex mixtures of toxic materials through smoke and ash that settle onto the landscape, contaminating soil and potentially exposing communities to hazardous metals. The 2025 Eaton Fire in Pasadena, CA, which spread rapidly from Eaton Canyon into residential neighborhoods, provides a critical case study for understanding these processes. Using a house-by-house sampling approach, I examine how heavy metals accumulate, persist, and redistribute over time in fire-impacted soils. Our integrates high-resolution spatial mapping, seasonal temporal monitoring, and targeted analysis of potential pollutant sources, including burned household materials, appliances, and vehicles (notably electric vehicles). This methodology enables us to trace specific sources of soil contamination, assess the effectiveness of remediation efforts, and identify persistent hotspots of elevated metal concentrations. Our work deepens the understanding of how wildfires alter urban environments and provides critical insights for shaping public health guidelines, improving post-fire soil remediation strategies, and protecting communities in fire-prone regions.