Photo: Patrick T. Fallon/AFP via Getty Images.
Researcher Danielle Stevenson digs up California buckwheat grown at a brownfield site in Los Angeles.
Given the mess we humans make of the environment, I have to be grateful that we can learn ways to clean things up. And to be fair, we don’t always realize we’re making a mess until it’s too late.
Richard Schiffman at Yale Environment 360, explains one new technique for cleaning things up: harnessing the power of fungus.
“The United States is dotted with up to a million brownfields — industrial and commercial properties polluted with hazardous substances. These sites are disproportionally concentrated near low-income communities and communities of color, according to the Environmental Protection Agency, and researchers predict that heavy rains and flooding due to climate change are likely to both spread and increase exposure to these contaminants.
“For more than 15 years, Danielle Stevenson, who holds a PhD in environmental toxicology from the University of California, Riverside, has been pioneering a nature-based technique for restoring contaminated land, using fungi and native plants to break down toxins like petroleum, plastics, and pesticides into less toxic chemicals.
“The usual way of dealing with tainted soil is to dig it up and cart it off to distant landfills. But that method is expensive and simply moves the problem somewhere else, Stevenson says in an interview with Yale Environment 360, ‘typically to another state with less restrictive dumping laws.’
“In a recent pilot project funded by the city of Los Angeles, Stevenson, 37, working with a team of UC Riverside students and other volunteers, significantly reduced petrochemical pollutants and heavy metals at an abandoned railyard and other industrial sites in Los Angeles. While her research is still in its early stages, Stevenson says she believes her bioremediation methods can be scaled up to clean polluted landscapes worldwide.
“Yale Environment 360: I understand that you grew up on the shores of Lake Erie in a highly polluted area.
“Danielle Stevenson: The Cuyahoga River, near Lake Erie, used to catch on fire from oil spills. There’s a huge amount of industrial agricultural runoff that leads to toxic algae blooms. The second-largest floating plastic island of the Great Lakes is in Lake Erie.
“But I was surprised to see abandoned oil refineries and factories with trees, plants, and mushrooms growing. I mean, they’ve found fungi growing in Chernobyl in a melted down nuclear reactor. I’ve been on sites that look so desolate and bleak, where the air smells like diesel. It looks like nothing could possibly live there. But when we sample the soil, we always find life, and we especially find fungi that are really resilient and have found a way to live in those conditions and get some sort of food from the pollution.
“e360: So you became interested in fungi, eventually founding your own mycoremediation company, D.I.Y. Fungi. What are fungi?
“Stevenson: They are their own kingdom of life. They are not bacteria, not a type of plant or animal. Some fungi form mushrooms [as their fruiting bodies], like the ones we like to eat. Other fungi do not form mushrooms but create these beautiful dynamic networks throughout forests and grasslands that connect to the roots of plants. Fungi are largely overlooked, but it is a really important kingdom without which we wouldn’t have soil or the carbon cycle or so many other really important functions in our ecosystems.
“e360: How do fungi help restore contaminated soil?
“Stevenson: Decomposer fungi can degrade petrochemicals the same way they would break down a dead tree. And in doing so, they reduce the toxicity of these petrochemicals and create soil that no longer has these contaminants or has much reduced concentrations of it. They can also eat plastic and other things made out of oil, like agrochemicals. …
“e360: You worked at industrial sites in Los Angeles that were highly contaminated with heavy metals: How did the fungus help there?
“Stevenson: Unfortunately, most metals don’t break down because they’re not carbon-based. In nature, it’s actually plants that pull metals out of soil. And so there are fungi, they’re called arbuscular mycorrhizal fungi, that can help plants do that better. And so on Taylor Yard [the Los Angeles railyard] and other sites, I’ve worked with a combination of decomposer fungi, arbuscular mycorrhizal fungi, and plants that we previously found to be able to pull metals like lead and arsenic out of the soil into their aboveground parts. These plants can then be removed from the site without having to remove all of that contaminated soil.
“e360: How did the sites look different after the work that you did on them?
“Stevenson: They became basically beautiful meadows of native plants that were flowering, and now there are bees and birds and all sorts of life coming through. We had a very high success rate. In three months we saw a more than 50 percent reduction in all [petrochemical] pollutants. And then by the 12-month period, they were pretty much not detectable.”
The rest of this article — on reusing some metals, on working with tribes — is fascinating. Read at e360, here. No paywall.
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