On a former landfill site in Northeast Portland, a white rot fungus has taken hold – and that's a good thing. It's a mushroom known for its ability to clean up water pollution.
The landfill was once a rock quarry, and it was used to dump the construction debris leftover after building I-84 and I-205 in the 1970s. As that waste deteriorates, the landfill has released methane gas and various pollutants into the soil and groundwater.
"There's a lot of things to watch out for," said Mike Slater, Brownfield project manager for the Environmental Protection Agency. Before the Zen Center leaders can fully redevelop the property, he said, there is more cleanup work to be done.
The cleanup project recently received at $200,000 grant from the Environmental Protection Agency to continue improving the soil and water quality on the contaminated site.
On Wednesday, while excavators added a layer of clean dirt on one end of the site, EPA employees and volunteers with the Zen Center were on the other end of the site mixing mushroom spawn with bark mulch and rolling it into into burlap bundles.
Mycologist Jordan Weiss is guiding the effort to use mushrooms to treat contaminated water running off the landfill. He said these "myco-filtration habitat buffers" will be placed at strategic locations around the property. The cap of clean dirt on top of the landfill is preventing rain water from picking up a lot of contaminants, but some of the water going through the landfill is seeping out of a ravine.
"We want to be sure that anything that does come out on the side of the ravine doesn't pose a health risk or any further liability," he said.
Weiss said the root-like mycelia in the mushrooms create a barrier for water to pass through that catches and breaks down bacteria and pollutants. The mushrooms won't necessarily remove all the pollutants leaching out of the landfill, he said, but they will help.
"They'll be creating new geography where they're placed – a healthy, physical structure that will be able to filter water," he said.
Anthony "Fujaku" Stevens works with the Zen Center. He says some of the mushrooms they're growing may be clean enough to eat.
"But there's still an area down on the far side of the property where there's a lot of metals coming up and a lot of stuff coming up that's not so good," he said. "So, we're using the mushrooms more as a way to clean the soil but we're not going to eat them."