Functional Fungi: How Mycelium Can Help Remove Soil Contamination

You might be familiar with mushrooms on a tree stump or your pizza, but did you know mushrooms can be used for pollution cleanup? As nature’s decomposers, this is the job fungi were made for!

CCLR is dedicated to pursuing creative solutions to land revitalization and we want to know: could fungi be the future of in-situ site cleanup? To help us answer this question, we turned to biological remediation expert Danielle Stevenson, PhD and Environmental Scientist at the University of California in Riverside.

Biological remediation works with living organisms like plants, bacteria and/or fungi to address contaminants in the environment. Fungi have largely been overlooked for remediation even though they are the main decomposers in soils across the globe and could help ‘heal’ soil contaminated from the petroleum, chemical, and manufacturing industries.

You might wonder how mushrooms do this amazing stuff? First we need to get our vocabulary right. Fungus (plural fungi) is any spore-producing organism that feeds on organic matter including molds, yeast and mushrooms. Mushrooms are the fruiting bodies or reproductive parts of certain fungi. Mycelium is the vegetative part of a fungus, consisting of a web of threadlike structures that takes in food and water.

Mycelium – the white stuff – seen growing underground in petrochemical contaminated soil at one of Danielle’s field study sites. Photo: Danielle Stevenson.

Fungi play essential roles in plant growth, carbon cycles, soil creation and so much more. Their potential for remediation comes from their role in nature and how they get their food. While mushrooms are the part of the fungi we most often see, they don’t actually do the hard work of breaking down pollution. It is mycelium that is responsible for remediation.

There are three different ways that mushrooms can remediate contaminated soil.

Decomposer Fungi like oyster mushrooms can “eat” organic contaminants such as diesel using their built-in enzymatic process. Because of how similar these contaminants are to what they naturally eat, fungi can break them down and absorb them into non-toxic forms!

Endophytic fungi live inside of plants in a symbiotic relationship that benefits both plant and fungi. They can act as decomposers of organic contaminants or help plants grow, enhancing phytoremediation success.

Mycorrhizal fungi connect with the roots of plants —more than 90% of all plants form these relationships— and trade nutrients, water and more. Mycorrhizal fungi can be applied to enhance phytoremediation success by helping plant survival in polluted soils and potentially enhancing metal removal by plants.

Danielle undertook field phyto-mycoremediation studies at three brownfields in Los Angeles through the Environmental Toxicology Graduate Program at University of California Riverside. She tested how the addition of decomposer fungi available from the waste stream and/or mycorrhizal fungi with and without irrigation affected soil organic contaminant (diesel, gasoline, solvents and PAH’s) and metals of concern (lead, arsenic, chromium and others) concentrations with California native plants she had identified in a previous study to accumulate metals.

The goal was to test how these combined remediation methods, utilizing multiple types of fungi with plants, could address the mixtures of metals and organic contaminants commonly found on brownfields, on a larger scale and in the real conditions of contaminated sites. These studies built on Danielle’s previous studies with mycoremediation on contaminated sites of urban agriculture and toxic wastes through projects such as D.I.Y. Fungi and Healing City Soils.

Mushrooms sprouting in Danielle’s Phyto-mycoremediation study plots. Photo: Danielle Stevenson.

Danielle’s studies are among very few field tests of mycoremediation in the United States. Results from the one-year study were promising. Previously untested California native plants were found to accumulate metals like lead and arsenic. And the addition of mycorrhizal fungi enhanced phytoremediation success. Small but statistically significant reductions in soil metals were seen in treated as compared to control plots (with no treatments). The addition of decomposer fungi degraded organic contaminants including diesel, PAH’s and gasoline, with more than 50% removal in 3 months.

Next steps include additional field studies and pilot projects to test the best combinations of plants and fungi determined in this first study under different conditions and at larger scales, with an attempt to further optimize the methods. Another important area of future research is optimizing recycling of plants used in phytoextraction of metals, since they are a byproduct of the remediation process that potentially need treatment currently as a hazardous waste.

Research into mycoremediation deserves investment. It’s more cost-effective than conventional remediation, it can be performed in-situ removing or reducing the need for soil excavation, it can be applied in conjunction with other bioremediation strategies such as phyto and bacterial to enhance their success and rapidity, it can potentially address multiple types of contaminants and it is generally swift at removing organic contaminants, while producing a fraction byproducts of the remediation process as traditional dig and haul methods where tons of soil may need to be removed and disposed of. Since we work with the fungal mycelium rather than the mushrooms, it is possible to have no byproducts, although if mushroom-forming fungi are utilized, any mushrooms that form should not be eaten and would need to be disposed of properly.

Danielle is launching an institute to advance mycoremediation research, services and training/workforce development and is seeking contaminated sites in California for potential pilot studies, facilities space, instrumentation supplies and other resources. Her work is pivotal in the implementation of this technology on brownfields and across California. If you are interested in learning how you can support this type of research, or have a contaminated site that you’d like to consider for a pilot study, please contact CCLR or Danielle at or via her personal website or the institute’s website.

Additionally, if you’d like to learn more about mycoremediation, register for CCLR’s webinar Functional Fungi: Bioremediation Strategies for Brownfields with Danielle Stevenson on May 29th from 11:00 a.m. -12:00 pm. PT.

Danielle Stevenson presenting her research at the 2023 California Land Recycling Conference.