Tobacco may be bad for human health, but a new study reports that a genetically engineered tobacco plant may be very good for the environment. It shows promise for cleaning up soil contaminated with TNT, a widely used military explosive.

Neil C. Bruce and colleagues noted that TNT contamination is a major environmental problem at many World War II sites, military training areas, and explosive manufacturing sites. In addition to being explosive, TNT is toxic and a human health threat. Researchers knew that certain soil bacteria could metabolize and change trinitrotoluene (TNT) into nontoxic compounds. But those natural bacteria exist at levels too low to detoxify TNT.

In the new study, researchers inserted a gene for a TNT-transforming bacterial enzyme into a tobacco plant. Then they tested the plant's effect on TNT-contaminated soil in comparison to regular tobacco plants grown in the same soil for several weeks. The genetically modified plants significantly reduced the toxicity of the TNT-contaminated soil.

"This is the first report to demonstrate that transgenic plants engineered for the phytoremediation of organic pollutants can increase the functional and genetic diversity of the bacterial community in acutely polluted soil compared to wild type plants," the report states. "Our findings have important implications, not only for use of genetically engineered plants for TNT remediation, but for cleaning up other sources of contamination as well."

The article "Impact of Transgenic Tobacco on Trinitrotoluene (TNT) Contaminated Soil Community" is scheduled for the Aug. 15 issue of ACS' Environmental Science & Technology.