A microscopic mushroom that laps up oil like a thirsty puppy could provide a cheap, efficient way to clean up polluted soil, according to researchers at the University of Montreal. If the research bears out, the discovery could add another item to the growing stockpile of phytoremediation tools — plants that can be deployed to remove toxic substances from soil and groundwater through natural processes, without the enormous carbon footprint involved in traditional cleanup methods.
What’s Wrong with Traditional Clean-Up Methods?
Conventional cleanups for polluted soil generally involve the expenditure of vast amounts of energy. A typical project might involve excavating contaminated soil out of one site and dumping it in another, or pumping large quantities of contaminated water through treatment plants. In recent years the trend has been to find ways of getting rid of the pollution without shifting soil and water around, and that’s where the ‘shrooms come in.
Helping Plants Suck Pollutants Out of Soil
Conventional phytoremediation involves using hardy plants to suck up pollutants from soil as they grow. Substances such as heavy metals can then be removed by harvesting the plants, which can be incinerated (or perhaps some day, used as feedstock for biofuels). The Montreal project involves a new twist, which is to enhance the work of the plants by spiking the soil with bacteria and microfungi. A member of the research team, biochemistry professor B. Franz Lang, explains that “it isn’t the plant doing most of the work, it’s the microorganisms i.e. the mushrooms and bacteria accompanying the root.” The team has performed tests using willow shoots, which grow rapidly and have deep roots, and the next phase of the research involves finding the most efficient combination of plants with mushrooms and bacteria.
Willow Trees, Corn Stalks and Phytoremediation
The Canadian project is similar to another promising phytoremediation project under way in Michigan’s “Copper Country,” parts of which have been described as a moonscape. In this project, researchers have spiked pots of regular soil with a bacteria that they found thriving in areas heavily contaminated with waste from abandoned copper mines. Corn planted in the pots would normally do poorly, but in the presence of the bacteria the corn grew robustly and absorbed the copper. Future steps will involve moving the process out of the greenhouse, and planting corn at actual contaminated sites (like willow, corn is a popular phytoremediation plant because it grows rapidly and produces a relatively large amount of biomass).
For more information on phytoremediation and other emerging low cost, energy efficient waste cleanup strategies, check out the U.S. EPA’s clu-in.org website.
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