Can the Community Salvage Its Gardens After the Eaton Fire?

Pasadena High School students planting microgreens. Photo by Jill McArthur.

Altadena and Pasadena communities are working to reduce toxic lead levels in their soil and restore its health after the January 7th Eaton Fire. 

Urban infrastructure that burned in the Eaton Fire resulted in large amounts of lead from buildings entering the environment. Last week, the Los Angeles County Department of Public Health shared preliminary heavy metal testing results from several property sites that were burned by the fire, revealing elevated levels of lead in the soil, a toxic metal that is harmful when ingested. 

Residents have had to limit their interaction with the soil, including gardening and growing crops. To mitigate the toxicity in the soil, they have begun using a two-part process for soil remediation to reduce the harmful effects of lead. 

Christine Hinkle, an environmental consultant, is working to combat lead levels by addressing the soil's poor microbial activity after the fire. “Reintroduce and replenish what has been killed off,” Hinkle said.

Pasadena and Altadena community members are applying compost, a nutrient-rich decomposed matter, to burn sites to restore beneficial microorganisms to the soil. Compost contains microbes that remove lead from the soil. It also supports California native plants that detoxify lead in the soil. Through their efforts, communities are trying to grow and eat their own produce again without the risk of lead exposure. 

In the Eaton Fire’s immediate aftermath, the Army Corps of Engineers decided not to conduct soil testing in the burn sites. Instead, they focused on clearing 6 inches of debris-covered soil from the affected areas. Preliminary lead testing results were only released on April 11th. 

According to results released by Roux Associates, a testing company hired by the Los Angeles Department of Public Health, lead levels exceeded the California state standard of 80 milligrams of lead per kilogram of soil in the vast majority of samples (80%) across 780 properties. Testing has not yet expanded to every plot of land affected by the fire, including school gardens. 

Jill McArthur, a Pasadena Unified School District coordinator, said that the Department of Public Health informed the district that no one could eat anything from gardens until the full results from soil testing were available. 

“The directive that was issued in January still stands,” McArthur said. 

The community has expressed frustration over how long it has taken public health to release the lead-level results, she added. “A big part of what is difficult is for people to feel like they are not getting the full picture.” 

McArthur, who teaches agriculture to high school and middle school students in on-campus gardens, regards people who have lost their homes and community gardens. McArthur said, “are realizing this food source is gone.” Since the fire, she has set aside indoor spaces for students to grow produce to combat the community's inability to grow their produce outside. 

Outside of the 780 properties recently tested by Public Health for lead levels in Pasadena and Altadena, uncertainty remains. 

Christine Hinkle and her team have conducted lead tests on a handful of Altadena properties since the fire broke out. She said she had found elevated lead levels consistent with the Public Health test results. 

Hinkle said she uses a “biomimicry” approach in properties with high lead levels. The approach uses nutrient-rich compost to revitalize the soil on burned properties, restoring beneficial microbes lost in the blaze. 

“When the fire is coming through, we want to look to see who’s still alive,” she said. “When we look at that under a microscope, we can identify and do a count.”  Based on the results, the team determines what microbes the soil lacks and creates compost that fulfills its microbial needs. 

Hinkle said her team uses them to immobilize and absorb lead in the soil, reducing its concentration. Over the last few weeks, Hinkle has been periodically re-testing the soil samples that have had the nutrient-rich compost solution applied. When examining the diversity of microbes,

 “If they exist in the right numbers, then we know the soil is healthy,” she said. “I have confidence that the soils can be restored. It remains to be seen whether to the same level,” she said, referring to the new process underway. 

Kyle Michealsen, a Pasadena High School agroecology teacher, uses California native plants to detoxify lead in soil. Plants undergo a process of removing lead from the soil by absorbing it into their tissue. Native plants are effective at breaking down lead due to their relationship with microbes. After absorption, plants degrade or stabilize the lead to prevent it from spreading further. 

Michealsen said his teaching has steered toward using plants to address soil toxicity. His students have begun volunteering in school gardens throughout Pasadena, such as Washington Elementary School. 

They have been moving contaminated soil from plant beds to isolated areas where non-edible native plants are growing. “The hope is that there are plants that can restore some of that soil and take the toxicity out,” he said. 

With soil restoration underway, time will tell how effective composting and native plants will be for restoring soil throughout Pasadena and Altadena communities to its original state.