´óÏó´«Ã½

When I moved to my waterfront farm on Skookum Inlet, Washington state, I inherited six Angus cows. An inspection showed that the outflow of water from my property was jeopardizing the quality of my neighbor’s commercial shellfish beach, with the bacteria count close to the legal limit. I decided to install an outdoor mushroom bed in a gulch leading to the beach. The following year, after the mushroom beds were colonized with mycelium, the coliform count had decreased to nearly undetectable levels. This led to the term I have coined “mycofiltration,” the use of fungal mats as biological filters, which has become my passion and my vocation. 

	Photo by Susan Thomas

Mycelium—the network of fungal cells—produces extracellular enzymes and acids that can dismantle long chains of hydrogen and carbon, the base structure common to oils, petroleum products, pesticides, PCBs, and many other pollutants. For the past four years I have been working with Battelle Laboratories, a non-profit foundation widely used by the United States and other governments in finding solutions to toxic wastes. We began a series of experiments employing the strains from my mushroom gene library, many of which came from specimens collected while hiking in the old growth forests of the Olympic and Cascade mountains.

After several years, and redundant experiments to prove to naysayers that our data were valid, we have made some astonishing discoveries. The first significant study showed that a strain of Oyster mushrooms could break down heavy oil. A trial project at a vehicle storage center controlled by the Washington State Department of Transportation enlisted the techniques from several competing bioremediation groups. The soil was blackened with oil and reeked of aromatic hydrocarbons. We inoculated one berm of soil approximately 8 feet by 30 feet by 3 feet high with mushroom spawn, while others employed a variety of methods, ranging from bacteria to chemical agents. After four weeks, the tarps were pulled back from each test pile. The first piles employing the other techniques were unremarkable. Then the tarp was pulled from our pile, and gasps of astonishment and laughter welled up from the observers. The hydro-carbon-laden pile was bursting with mushrooms! Oyster mushrooms up to 12 inches in diameter had formed across the pile. Analyses showed that more than 95 percent of the PAH (polycyclic aromatic hydrocarbons) were destroyed, reduced to non-toxic components. The mushrooms were also free of any petroleum products.

After eight weeks, the mushrooms had rotted away, and then came another startling revelation. As the mushrooms rotted, flies were attracted, feeding on the mushroom spores. The flies became a magnet for other insects, which in turn brought in birds. Apparently the birds brought in seeds. Soon our pile was an oasis, the only pile teeming with life.

Another discovery is that one species of mushroom can be used to break down VX, the potent nerve gas agent Saddam Hussein was accused of loading into warheads during the Gulf War. I’ve also found that a mycelium-inoculated mulch bed makes an effective filter for farm runoff. We’ve used the same method in restoring closed roads, thousands of which are left over from logging and which are one of the greatest threats to water quality in the US.

Although we have looked at just a few of the mushroom species resident in old growth forests, clearly these ancestral strains of mushrooms have survived millennia due to their inherent ability to adapt. These adaptive mechanisms are the very foundation of ecological stability and vitality in a rapidly changing environment.