At the ESPAÑOLA HEALING FOODS OASIS in ESPAÑOLA, NEW MEXICO, Pueblo dryland farming techniques are on display in a downtown public park. The garden, designed and planted by the Indigenous-led organization Tewa Women United, demonstrates how food and medicine can be grown in an environment that receives just 11 inches of rain per year. But they have a problem: The soils are toxic.

Petroleum from a nearby parking lot percolates into the soil when it rains. Tewa Women United hopes oyster mushrooms will clean up the mess.

It’s worked before.

Mycologist Peter McCoy explains that in a process called mycoremediation, mushrooms have the ability to remove chemicals from soil — and heavy metals from water — through their mycelium.

“They’re sort of nature’s greatest decomposers, disassemblers, by far better than and more powerful than bacteria, animals, and plants,” said McCoy. “They break all kinds of stuff down.”

Mushrooms have helped remove petroleum from soil everywhere from Orleans, California, where they cleaned up a small motor-oil-and-diesel-fuel spill at a community center, to the Ecuadorian Amazon, where they’re being used to clean up the largest land-based oil spill in history.

Beata Tsosie-Peña of Santa Clara Pueblo is the program coordinator at Tewa Women United. She said her elders experience disease, illness, and miscarriage as a result of pollution in the area.

It’s not just the soils in the garden that are contaminated. At nearby Los Alamos National Laboratory, hexavalent chromium, a heavy metal and known carcinogen, is seeping into the water supply.

A coalition including Tewa Women United is advocating, through public testimony in a permit renewal process, that the laboratory use mycoremediation to clean up the heavy metals. They don’t yet know whether their recommendations will result in more stringent cleanup requirements. In the meantime, Tewa Women United is doing what it can to clean up petroleum at the Foods Oasis.

In April 2018, the organization buried bricks inoculated with oyster mushroom mycelium. They plan to test the soil in spring 2019 to see how the remediation worked.

“I think the mainstream view is that these places have been lost to us because they’re contaminated,” Tsosie-Peña said. “But to me, it’s like you wouldn’t just abandon your sick grandmother in the hospital to suffer alone.

“That’s how we feel about these places. They’re sick. They need healing. They need our love and attention more than ever.”

1 Mushrooms will eat anything

Fungi are the primary decomposers in most environments. They have developed unique tools for breaking down hydrocarbons and other organic chemicals.

2 It’s the enzymes

Scientists have identified more than 120 enzymes in the tissues of mushroom-forming fungi. These enzymes can break down toxic chemicals, including cancer-causing hydrocarbons found in oil.

Illustration from De Agostini Picture Library

3 Local mushrooms

Native mushroom species are best adapted to local conditions and therefore do the best job of cleaning up toxic messes.

Illustration from De Agostini Picture Library

4 It happens underground

Hydrocarbons with molecular weights are easier for the mycelium (the underground part of the fungus) to digest than those with higher ones. However, the mycelium gradually breaks heavier hydrocarlowerbons into lighter-weight compounds that are less harmful to people and the environment. With repeated fungal treatments, oil toxins can be rendered nontoxic.

Illustration from De Agostini Picture Library

5 Add some compost

Oyster mushroom mycelia break down hydrocarbons much more effectively when mixed with wood chips and compost. Researchers found one strain of oil-eating oyster mushroom that thrives in saltwater environments. The mycelium fully colonizes straw soaked with seawater.

6 Healthy soil

In one test, researchers inoculated diesel-contaminated soil with oyster mushrooms and found that they reduced the concentration of toxic hydrocarbons from a dangerous 10,000 parts per million to just 200 parts per million over a 16-week period. The remediated soil was so clean that regulators approved it for use in landscaping along highways.

Source:  Research by Paul Stamets, Fungi.com. Illustrations  from De Agostini Picture Library, Mark Longworth, Dorling Kindersley / Getty. Yes! Magazine Infographic, 2010 and 2019.