The researchers plan to plant transgenic poplars at the site, a former oil storage facility near Kokomo, Ind., this summer. In a laboratory setting, the transgenic trees have been shown to be capable of absorbing trichloroethylene, or TCE, and other pollutants before processing them into harmless byproducts.
Richard Meilan, a Purdue associate professor, is currently at work to transform one variety of poplar suited to Indiana's climate; cold-hardy poplars are generally more difficult to alter than the variety used in a laboratory setting.
"This site presents the perfect opportunity to prove that poplars can get rid of pollution in the real world," Meilan said.
In a study Meilan co-authored, published last October in Proceedings of the National Academy of Sciences, poplar cuttings removed 90 percent of the TCE within a hydroponic solution in one week. The engineered trees also took up and metabolized the chemical 100 times faster than unaltered hybrid poplars, which have a limited ability to remove and degrade the contaminant on their own, he said.
The transgenic poplars contain an inserted gene that encodes an enzyme capable of breaking down TCE and a variety of other environmental pollutants, including chloroform, benzene, vinyl chloride and carbon tetrachloride.
Meilan said he believes the transgenic poplars will be able to remove the TCE from the site, named Peter's Pond, which was contaminated by tainted oil stored there in the 1960s. The chemical, used as an industrial solvent and degreaser, lies within 10 feet of the surface, making it accessible to poplar roots, he said.
TCE, the most common groundwater pollutant on Superfund sites, is a probable human carcinogen and causes various health problems when present in sufficiently high levels in water or air.
Meilan said planting transgenic trees in the field remains controversial, primarily due to concerns that inserted genes, or transgenes, might escape and incorporate into natural tree populations.
"It is legitimate to be concerned about transgenic plants, but we are taking comprehensive steps to ensure that our transgenes don't escape into the environment," Meilan said.
Meilan has applied for a permit to grow transgenic poplars in a field, or non-laboratory, setting from the Animal and Plant Health Inspection Service, the government organization responsible for regulating such research activities, he said.
In order to comply with permit guidelines and to protect the environment, Meilan's team will take measures to prevent any plant material from leaving the site and will remove the trees after three years, short of the five it takes for poplars to reach sexual maturity, he said.
"Three years should be enough time for them to grow up, send down roots to suck the pollutants up and break them down," Meilan said. "Then we'll cut them down before they have the chance to pass on their genes to the environment."
Besides their utility in phytoremediation, or pollution removal, poplars have promise as a feedstock for cellulosic ethanol. To investigate their potential in this area, the U.S. Department of Energy awarded a $1.3 million grant to Meilan and two colleagues, professors Michael Ladisch, agricultural and biological engineering, and lead researcher Clint Chapple, biochemistry.
They are currently investigating ways to alter the composition of poplar lignin, which provides rigidity to the plant cell wall by binding to strands of cellulose, a complex sugar that can be converted into ethanol.
Chrysler will fund the Kokomo project and said that the TCE is contained within an isolated water table at Peter's Pond and presents no public hazard.
The original study, led by University of Washington professors Stuart Strand and Sharon Doty, revealed that the transgenic poplars also were able to absorb TCE vapors through their leaves before metabolizing the chemical. Tree cuttings removed 79 percent of the airborne TCE from a chamber within one week. This suggests poplars could one day help mitigate air as well as water pollution.
If the project succeeds, poplars may be used for phytoremediation elsewhere. Poplars grow across a wide geographic range and in many different climates, Meilan said.Writer: Douglas M. Main, (765) 496-2050, firstname.lastname@example.org
Douglas M. Main | EurekAlert!
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research