Scientists are planting new ecosystems that soak up the toxic substances from some of the most polluted areas in the world. Thousands of sites around the world are so steeped in oil, dioxins, and other chemicals that hardly anything can grow on them, plant or animal. Over time—perhaps hundreds or thousands of years—microorganisms will eventually evolve to cleanse and inhabit these environments, turning them back into livable zones again.
Rather than just waiting for nature to take its course, scientists are now speeding up the process by selecting fungi, microorganisms, and even trees to do the job in just a few years. Mohamed Hijri, a professor of biological sciences and researcher at the University of Montreal’s Institut de Recherche en Biologie Végétale (IRBV), has been engineering these toxic ecosystems. And he is succeeding.
"If we leave nature to itself, even the most contaminated sites will find some sort of balance thanks to the colonization by bacteria and mushrooms," says Hiri on the University of Montreal’s website. "But by isolating the most efficient species in this biological battle, we can gain a lot of time."
Working with a Montreal oil company responsible for several toxic sites, Hiri has collected a biological clean-up team that can turn what’s basically a moonscape into something habitable (at least by some species) over the course of just a few years. First, willow trees are planted in dense stands to soak up the heavy metal contamination and store it in the plant’s cells. Then, each season, the trees’ stems and leaves are burned, creating an ash residue full of heavy metals. Finally, specially selected (but naturally occurring) fungi and bacteria are released to metabolize the petrochemical waste. Even a highly contaminated soil, says Hiri, can be cleaned within a few seasons.
The project, "Improving Bioremediation of Polluted Soils Through Environmental Genomics," is a long-term experiment involving 16 researchers from the University of Montreal and McGill University who are busy sequencing the DNA of crucial species in the project. The next challenge? Finding the right combination among the thousands of plant, bacteria, and fungal species to do the job and engineering them to work even better. It’s a slow process, but faster than waiting for nature to fix our mistakes for us.