Oakland Bioremediation Experiment Could Offer Cheaper, Safer Toxic Cleanup

Adam Garret-Clark was managing a West Oakland tiny-home community in 2022 when a neighbor started cleaning up the property next door for redevelopment. Both parcels were contaminated by a former auto-wrecking business and pollutants including petroleum and lead have been found at the site, though testing is ongoing. Garret-Clark said the neighbor used a common remediation method, “dig and haul,” in which toxic soil is excavated and sent to a specialized landfill.

Throughout that process, polluted soil is supposed to be kept damp or contained under tarps so it doesn’t spread. But Garret-Clark said that in this case, it was left in a dry, exposed pile and dust from it blew into the neighborhood. The pile stayed there for weeks before it was carted away, he said. He regularly visited the community, his former home, to manage it and on a particularly windy day he changed his plans and left to protect his health. 

“I knew the stakes of that dust blowing in my face,” he said. 

Now Garret-Clark is trying to test a remediation method that might be cheaper and safer than dig and haul at the former tiny-home community. Backed by a grant of more than $700,000 from the state Department of Toxic Substances Control, Garret-Clark plans to try out bioremediation, a process in which plants and fungi pull up or break down contaminants in soil, on a former auto-wrecking yard in West Oakland. He hopes the project will break trail for more widespread bioremediation of the thousands of contaminated sites across the Bay Area, which disproportionately burden marginalized communities of color.

But the pilot has also given Garret-Clark a front-row seat to some of the barriers to cleaning up the region’s toxic sites. 

Pilot has promise but faces systemic hurdles

Cleaning up pollution is expensive, Garret-Clark has found. Even before cleanup begins, a property owner pursuing remediation must pay for sampling and testing by an environmental consultant and then for state regulators’ review. Both parties’ highly skilled labor is expensive, to where it could easily discourage a property owner from embarking on cleanup, Garret-Clark said. 

Garret-Clark has also been taken aback by how difficult it has been to move his pilot forward. 

“There’s a shocking amount of administrative time before you can do anything,” Garret-Clark said. “We’re up against red tape.” 

The environmental consultant he hired for the project composed three drafts of a preliminary site risk assessment and each draft took roughly two months to complete, he said. Those drafts got turned over to the state Department of Toxic Substances Control for review. Garret-Clark said the agency has taken roughly a month to review each draft report and asked for multiple rounds of revisions.

The project’s timeline is not unusual for an investigation, said Jim Bergdoll, a technical advisor to the project with the Center for Creative Land Recycling, a nonprofit that facilitates reuse of brownfields, which are sites with suspected or known contamination. Nevertheless, it has eaten into the two-year grant funding period. 

Though the agency encouraged Garret-Clark to apply for the grant, he has found his experiment does not fit well within the grant’s structure. He received a site investigation grant, which is for assessing contamination and appropriate remedies rather than testing the efficacy of possible remediation methods, so the agency is focused on diagnosing the contamination at the site before greenlighting the experiment.

That process has taken so long, Garret-Clark said, that he might run out of time to complete the pilot project before the funding period ends next March, as the plants and fungi would need about a year to complete their work. Garret-Clark said he could apply for an extension, though it’s not guaranteed the agency would grant it. The state agency could also decide, after reviewing the latest rounds of tests, that the site is insufficiently polluted to warrant a full cleanup or that bioremediation is not an appropriate method. 

In a statement, an agency spokesperson said the agency is still in the early stages of investigating the site and is reviewing the first investigation report. The agency said it appreciates Garret-Clark’s vision for tiny homes on the site and will continue working closely with him to ensure that he can move forward once the environmental uncertainties are resolved.

“Historically, it has been difficult to work with regulators. They’re very risk-averse. In the case of something more innovative, it might take a while,” said Sebastian Harrison, an environmental engineer contracting with the Center for Creative Land Recycling and technical advisor to the project.

Bioremediation seen as relatively safe and cheap

Garret-Clark plans to remediate 1790 10th St., a former auto-wrecking yard in West Oakland that is polluted with polychlorinated biphenyls, also known as PCBs, which research strongly suggests are carcinogenic and can harm the immune, reproductive, nervous and endocrine systems. The pilot’s tests have also turned up petroleum and heavy metals but testing is ongoing to determine whether the amounts are harmful. 

Danielle Stevenson, an environmental toxicologist, has conducted bioremediation for 15 years and devised the pilot project work plan for Garret-Clark’s site based on brownfield cleanups she has designed across California. That entailed determining what palette of plants and fungi would best break down the site’s contamination. Brownfields tend to be polluted with metals and gasoline, and a similar mix is often effective across sites.

Stevenson typically combines plants that draw pollutants from the soil with a variety of fungi that break down contaminants and bolster the growth of the other plants. Most of the fungi aren’t the charismatic kind that form mushrooms, but rather black molds (like what you might find in an unventilated bathroom) and yeasts. 

As the plants grow, they pull toxins from the soil. Those pollutants get concentrated in the plant. Following bioremediation, the contaminated plant matter can be incinerated or turned into a slurry, which can be disposed of in a toxic waste landfill. That ultimate output is a much smaller volume of toxic waste than that of dig and haul, said Stevenson. While the plants are growing,  kinds of fungi that don’t produce a mushroom body will simply break down and consume pollutants as food until none are left. 

“They work themselves out of a job,” Stevenson said. 

Pending approval of their work plan from the state agency, Garret-Clark and Stevenson hope to begin the pilot this summer and hire and train West Oakland residents to help with the bioremediation, which includes introducing the right plants and fungi. The plan is to divide the property into subplots where they can test various combinations of plants and fungi. 

Stevenson, who has founded an organization for bioremediation education, hopes to spread knowledge of these alternative methods and make the pilot replicable in other Oakland neighborhoods. 

“You can’t really study this stuff anywhere,” Stevenson said. “There are very few people with the skillset to carry this out.” 

At the same time, bioremediation techniques have a relatively low barrier to entry. In communities of color with an unfair share of pollution like West Oakland, she and Garret-Clark hope to teach people to protect themselves and their neighbors. 

Stevenson and Garret-Clark believe bioremediation offers a better alternative to digging up toxic soil and hauling it to toxic waste landfills. Removing toxic soil is costly and can be hazardous. During excavation and trucking, toxic dust can blow into surrounding areas and sicken residents.

Polluted soil, which already disproportionately burdens communities of color, is often shipped to locations where it may affect other vulnerable groups. Almost half of California’s contaminated soil is taken to other states like Arizona and Utah, sometimes to landfills near Native American reservations. Environmental justice advocates have protested this practice, saying it simply exports toxic waste from one community to another. 

Between the excavation labor, trucking and landfill fees, dig and haul costs about $200 per cubic yard versus roughly $50 per cubic yard for bioremediation, said Harrison, the technical advisor. Harrison said that estimate was based on his experience doing cost analyses for remediation projects. 

The main drawback to bioremediation is that it can take longer. Some developers might prefer to move forward with the fastest option, but in the Bay Area, where development can move slowly due to red tape, bioremediation might make economic sense, said Harrison. 

“This is a really good passive option for people to do while they’re figuring out what to do with their site,” said Bergdoll, the other technical advisor. “Digging and hauling soil is very expensive. If somebody wasn’t in a hurry, it offers a big advantage.” 

Industry norms might also be holding back the proliferation of bioremediation. Dig and haul is the common, expected method and is easier for people to understand, Harrison said. 

“Dig and haul, it’s like a surgery,” Harrison said. “Chemically, bioremediation is a longer process with more sampling and a lot of high-level science.” 

“The industry is slow to change,” he added.