Discovering Soil Quality: Our Comprehensive Testing Journey in Altadena and Pacific Palisades

In late March, a dedicated team from the Los Angeles Times set out to investigate soil quality in areas affected by recent wildfires. They focused on locations in Eaton and Palisades, collecting 40 soil samples from homes—20 from properties that had completed debris removal and 20 from standing homes.

Wearing protective gloves and boot covers, the reporters carefully gathered five soil cores from various spots on each property. For destroyed homes, they sampled the area where structures once stood, specifically within a cleared footprint. This cleaning process had removed up to six inches of topsoil.

The team combined these samples into a single composite sample meant to represent overall conditions on each property. This composite approach helps provide a balanced view, acknowledging that some areas might be more contaminated than others. After every collection, they cleaned their tools and changed protective gear to avoid cross-contamination.

The samples were securely stored and kept cool until they were sent to BSK Associates, a lab known for post-fire environmental testing. Using an EPA-approved method, the lab analyzed 17 metals commonly found in fire-impacted soil. They utilized advanced technology to differentiate elements based on their atomic mass, allowing them to gauge the concentration of various metals accurately.

Throughout the process, the team maintained strict documentation to ensure the integrity and chain of custody for each sample. They consulted previous studies from other fires to align with established best practices for soil testing.

To select the properties to study, they relied on state data regarding fire damage and debris removal status. All homeowners involved provided consent, with their addresses kept confidential.

While the methodology was cautious, relying on composite sampling can dilute results from more contaminated areas. Traditionally, several composite samples would be taken from larger properties, but in this case, only one was collected regardless of size. This means some smaller contaminated spots might have been overlooked.

The findings were concerning: two properties cleared by the Army Corps showed levels of arsenic and lead above state safety standards. Additionally, three homes in Altadena had unsafe levels of arsenic, lead, and mercury, while only one sample from the Palisades area reported elevated arsenic levels.

This rigorous testing highlights the ongoing risks that remnants of wildfires pose to soil health, emphasizing the need for continued monitoring and results-driven action for affected communities.

For more detailed information on the effects of wildfires on soil and how these tests were conducted, visit BSK Associates and California Department of Forestry and Fire Protection.

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