The developed world is dotted with millions of ugly brownfield sites - industrial and commercial properties polluted with hazardous substances.
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.
In a recent pilot project funded by the city of Los Angeles, Stevenson and her team significantly reduced petrochemical pollutants and heavy metals at an abandoned railyard and other industrial sites in LA. 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.
Alongside traditional decomposer fungi, the mixture of life forms demonstrated tremendous results. “In three months we saw a more than 50 percent reduction in all pollutants. By 12 months, they were pretty much not detectable,” Stevenson told Yale 360. "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."
Stevenson - who founded mycoremediation company, D.I.Y. Fungi - says that 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.