California Pollution Gets Cleaned Up by Fungi and Plants

In the industrial wasteland of Los Angeles, Kreigh Hampel is plucking California buckwheat with a pitchfork to see how much lead it has absorbed.

The plant’s delicate white and pink blossoms are beyond amazing with cleaning power, which scientists believe can be harnessed to get rid of dangerous pollutants—and even recycle them.

“This is the miracle of life,” says Humble, 68, who volunteers with the project.

“Plants really can do this work and they know how to do it, and they’ve done it many times over millions of years,” he says.

The experiment is part of a project run by the University of California Riverside that has dispersed carefully selected plants and fungi at this former industrial site in hopes of ridding the heavy metals and petrochemicals that have polluted the area for decades.

These bioremediation techniques can be more cost-effective than conventional techniques, says Danielle Stephenson, who led the study.

“The traditional way to clean up the sites is to just dig up all the polluted soil and dump it somewhere else,” she told AFP.

“This approach doesn’t actually solve the problem, does it? It just moves it somewhere else.” She says it costs a lot of money.

Stevenson’s project, which is being carried out on three sites in and around Los Angeles, is priced at about $200,000 and so far is showing very promising results.

Solar powered vacuum cleaners

“In three months, we got a 50 percent reduction in petrochemicals, and then in six months, we’re pretty close (to that level) with some metals,” she said.

A mycologist by training, Stevenson chose her antifouling weapons carefully.

Oyster mushrooms are incorporated into the soil because of their natural role in decomposing: the underground part, called the mycelium, absorbs the diesel.

“Those same fungi that eat a dead tree in nature will also recognize diesel oil, for example, as a food source.

“The reason is that it’s basically the same thing. A lot of our fossil fuels are just dead stuff that’s been compressed over long periods of time.”

Many plants native to california, including telegraph weed and california sunflower, are particularly good at absorbing heavy metals.

Stevenson believes that plants are essentially “solar vacuum cleaners: they absorb metals, such as lead, into their bodies.

“When we take the plants out, we’ve removed the lead from the soil.”

The lead and other metals from those plants could then be recovered — and even reused.

Across the United States and the industrialized world, Stephenson says, commercial sites that outlive their useful lives are often abandoned to the companies that pollute them.

Responsibility for correcting them falls on poorly funded or ill-equipped local authorities, who struggle to find money or expertise.

Historically, the problem has been worse in working-class or ethnic-minority neighborhoods, where politicians feel better able to ignore complaints.

Stevenson says that in the United States, where the Environmental Protection Agency lists nearly 1,900 problem sites, only a small number of cleanup projects are undertaken each year.

She hopes the cheaper method will enable more sites to be cleaned up.

‘the last of us’

Advocates say the uses of bioremediation are not limited to restoring former industrial sites. The process can also be used to help clean up toxic ash left behind by some wildfires—an annual problem in fire-prone California.

So why is this technology still so far behind?

“Bioprocessing is still considered too risky,” explains Bill Mohn, a professor of microbiology at the University of British Columbia in Canada.

Unlike soil digging, “it is difficult to ensure that you regularly reach the required level of contaminants.

“While we know that if you dig up the soil and send it to someone who will take it if you pay them, then you have solved your problem.”

Meanwhile, Stevenson points out unhealthy prejudices about mushrooms — think of the terrifying zombie-infecting fungus in HBO’s smash series “The Last of Us.”

“I get asked all the time,” she says, “If I introduce a fungus to clean up a site, will it take over, eat our house, and take over the world?” ”

You won’t, they are quick to add.

But that’s why it’s important to do this kind of experiment in a real environment, not just in a lab.

“I think once we do more field testing of these approaches, people will feel more confident in choosing some of these approaches,” she says.

© 2023 AFP