A research project has tested the ability of probiotics to boost the speed and effectiveness with which trees capture, remove and degrade pollutants from the soil.
Researchers from the University of Washington (UW) conducted the first large-scale experiment of this kind by inoculating poplar trees at a Silicon Valley test site with a microbial partner. Their ability to clean groundwater contaminated with trichloroethylene (TCE), a harmful pollutant commonly found in industrial areas, was then observed.
The results were published in the journal Environmental Science & Technology and suggested that inoculated trees could play a crucial role in enabling contaminated sites to be dealt with more effectively and at lower costs, both positive outcomes for the environment and human health.
In the initial stages of the project, researchers worked to determine which microbe strain could most effectively break down TCE by testing the effectiveness with which over 100 different microbes eliminated TCE stored in flasks.
They went on to inoculate some trees but not others with this specific microbe at the test site, which sits above a known groundwater plume contaminated with TCE. After a year, the trees inoculated with the microbe had grown bigger and healthier than those without it, despite the fact that taking up and degrading chemicals usually comes at the expense of the tree’s own health.
After three years, a sample of tree trunks revealed greatly reduced levels of TCE in the inoculated trees. Additionally, researchers found groundwater samples taken downstream from the test site contained reduced levels of TCE when compared to the higher levels found upstream. They also found increased levels of chloride, the naturally occurring by-product of TCE degradation, in the soil around the poplar roots.
Researchers say a number of organisations have indicated their interest in using this technology as a way to negate the high costs associated with traditional clean-up methods, including excavating and pumping.
“This has the potential to make a huge impact on a lot of legacy sites where you have contaminated groundwater issues, including TCE, and where funding is currently less available,” said co-author John Freeman, chief science officer for Intrinsyx Technologies Corporation based at NASA’s Research Park.
“This is definitely a big cost savings to everyone involved. It’s a real win-win situation because it’s green, it’s long-term sustainable, publicly acceptable and its solar powered by the trees themselves,” he said.
Source: Forestry Expo
