Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UGA researchers use transgenic trees to help clean up toxic waste site

11.09.2003


Can genetically engineered cottonwood trees clean up a site contaminated with toxic mercury? A team of researchers from the University of Georgia - in the first such field test ever done with trees - is about to find out.



The results could make clearer the future of phytoremediation - a technique of using trees, grasses and other plants to remove hazardous materials from the soil. UGA scientists and city officials in Danbury, Conn., planted on July 16 some 60 cottonwoods with a special gene at the site of a 19th-century hat factory in that northeastern city.

"We hope to see a significant difference in the levels of mercury in the soil within 18 months, perhaps as much as a twofold reduction," said Richard Meagher, professor of genetics at UGA.


The field test is a collaboration between UGA, Western Connecticut State University, Applied PhytoGenetics, Inc., of Athens and the City of Danbury.

While the technology now being used in Danbury does not apply to all sites, mercury pollution is a pervasive problem in Georgia as it is elsewhere. The site of a former chemical factory near Brunswick, for example, is polluted with mercury and other toxic chemicals. Mercury contamination has been reported around the sites of former gold mines in north Georgia, and advisories have been issued during the past decade for mercury-contaminated fish in more than 80 streams, lakes and creeks in the state.

Meagher’s team did the first-ever field trial of a genetically engineered plant to sequester mercury when it grew transgenic tobacco in a New Jersey field trial in 2001, but this is the first such trial using trees, whose larger root systems and year-round life cycle makes them better candidates for long-term cleaning of polluted soil.

Phytoremediation is a relatively new field and one gaining international interest. A team of photographers working for National Geographic, for instance, recently spent considerable time with Meagher capturing on film his work as part of a four-part documentary that will be aired some time next winter.

Meagher has for more than a decade been a pioneer in phytoremediation, and he was the first to demonstrate that a gene called merA can be inserted into plants and used to detoxify mercury in the environment. While no plant can break mercury down, since it is an element, less toxic forms can be created, and that has been the goal of Meagher’s lab - to find ways to let plants or trees grow on polluted sites, draw such heavy metals as mercury into the plants themselves and then either transpire the much less toxic forms of the metal into the air where they are quickly diffused or trap the metal aboveground for later harvest.

The project with Danbury came about because Danbury’s environmental coordinator, Jack Kozuchowski, had in 1977 published an early study that showed how native plants could transfer mercury from contaminated soils into the atmosphere. Kozuchowski, aware of Meagher’s work, convinced officials in Danbury that the so-called Barnum Court site in that town would be a perfect site for a field trial of the genetically engineered trees that Meagher and his collaborator Scott Merkle developed.

The city was awarded a grant of some $55,162 from the Environmental Protection Agency to explore use of the technology, and the trial was set up - though most costs for the work are being born by those involved in it.

"It is our hope that the research will lead to a cleansing of the Barnum Court property so the city can transfer the property for development," said Mark Boughton, mayor of Danbury.

Meagher’s mercury phytoremediation technology is exclusively licensed to Applied PhytoGenetics, or APGEN as it is called, and that Athens company has been instrumental in helping set up the field trial. (Meagher is a consultant to and cofounder of APGEN.)

Postdoctoral associate Andrew Heaton of Meagher’s lab and one other of Meagher’s students traveled to Danbury in July to supervise planting the genetically engineered trees on the site in enclosed plastic containers buried on the site.

Because the mercury on the site ranges, depending on location, from five to more than 300 parts per million, trials were set up to measure the effects of the cottonwood trees on progressively more polluted samples of soil. Forty-five plots, most planted with four trees each, are located on the site, which is in a mixed-use urban area and whose total area is less than an acre. (Some 15 plots have four merA trees, 15 are nonengineered or "wild-type" trees and 15 received no trees at all, so there are 120 trees in the field test.)

The form of mercury at the Danbury site is ionic mercury, a species that can be sequestered and transformed into less toxic metallic mercury in the transgenic trees and then transpired into the atmosphere. (Several forms of mercury were used in hat-making in the 19th century, but their toxic effects often sickened workers and led to the phrase "mad hatter," which described the process of neurological degeneration that came from working with the metal. In this part of New England, the symptoms of mercury poisoning were called the "Danbury shakes.")

Meagher’s lab actually has two genes that can effect phytoremediation, merA and merB, but since the merA is active on ionic mercury, the cottonwoods trees chosen for the Danbury trial express the merA gene.

"This is a field test, not a cleanup," said Meagher. "And we will be measuring mercury in both the soil and the trees to see just how much success we have in reducing the mercury levels in the soil. We are very optimistic that this technology will work."

While the trees at the site will have to be watered, the costs of that pale in comparison to traditional clean-up methods - digging up the polluted soil and hauling it off for storage at another site, possibly greater than $1 million.

A team of researchers from Western Connecticut State University will be studying the role of soil microorganisms in the potential clean-up of mercury on the site. According to the City of Danbury, the field test will run through the 2004 growing season, and if results are positive, genetically engineered cottonwood trees will be used to clean the whole site.

Kim Carlyle | EurekAlert!
Further information:
http://www.uga.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>