October 2003

Toxic Waste Destroyed by Genetically Altered Trees

A team of researchers from the University of Georgia (UGA) has begun an experiment to test the possibilities of using genetically modified trees to clean up a site contaminated with toxic mercury. Trees are increasingly being used as tools for cleaning contaminated sites.

The UGA scientists planted modified cottonwood trees at the site of a nineteenth century hat factory in Danbury, Connecticut, as a field trial of phytoremediation processes, in collaboration with Applied Phytogenetics Ltd.

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

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

The trees use a gene called merA, which can be inserted into plants and used to detoxify mercury in the environment. Although mercury cannot be broken down, less toxic forms can be created. Meagher says this has been the goal of his work – to find ways to let plants grow on polluted sites, draw in heavy metals like mercury and then either transpire the less toxic forms into the air, or trap the metal above ground for easy removal.

Forty-five plots of trees are located on the site, which is in a mixed-use urban area. The mercury, contaminating the soil from the former hat-making process, is ionic mercury which can be sequestered and transformed into less toxic metallic mercury in the transgenic trees.

The researchers say that the cost of using this phytoremediation is far cheaper than traditional clean-up methods and the field test will run through the 2004 growing season. If results are positive, genetically engineered trees will be used to clean the whole site.

According to the EPA there are over 200 contaminated sites in the U.S. where phytoremediation is being used for clean-up. A team of researchers from the University of Georgia (UGA) has begun an experiment to test the possibilities of using genetically modified trees to clean up a site contaminated with toxic mercury. Trees are increasingly being used as tools for cleaning contaminated sites.

The UGA scientists planted modified cottonwood trees at the site of a nineteenth century hat factory in Danbury, Connecticut, as a field trial of phytoremediation processes, in collaboration with Applied Phytogenetics Ltd.

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

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

The trees use a gene called merA, which can be inserted into plants and used to detoxify mercury in the environment. Although mercury cannot be broken down, less toxic forms can be created. Meagher says this has been the goal of his work – to find ways to let plants grow on polluted sites, draw in heavy metals like mercury and then either transpire the less toxic forms into the air, or trap the metal above ground for easy removal.

Forty-five plots of trees are located on the site, which is in a mixed-use urban area. The mercury, contaminating the soil from the former hat-making process, is ionic mercury which can be sequestered and transformed into less toxic metallic mercury in the transgenic trees.

The researchers say that the cost of using this phytoremediation is far cheaper than traditional clean-up methods and the field test will run through the 2004 growing season. If results are positive, genetically engineered trees will be used to clean the whole site.

According to the EPA there are over 200 contaminated sites in the U.S. where phytoremediation is being used for clean-up.