Designer Plants Could Clean Up Heavy Metals

Bioremediation, the process of using organisms to restore toxic or damaged areas, could substantially reduce the costs of cleaning up the nation's superfund sites, estimated to require more than $700-billion.

Researchers at the University of California, San Diego have demonstrated that a chemical that permits plants to detoxify heavy metals can be transported from the roots to the stems and leaves, a finding that brings the possibility of using plants to clean up soil contaminated with toxic metals such as lead, arsenic and cadmium one step closer to reality. A paper detailing this discovery appears in an advance online publication of the proceedings of the National Academy of Sciences.

The active substances discovered by the UCSD team of biologists are phytochelatins, chemicals produced by an enzyme for which the team discovered the gene four years ago. Phytochelatins, it turns out, unexpectedly function in the root to leaf transfer of metals. Cleaning up a site usually requires extensive bulldozing to remove the affected soils which is costly, damaging to the environment and requires a disposal site for the contaminated soils. Instead, plants could be grown, harvested and then incinerated. However, there is still work to be finished on whether or not more gene manipulation is required in the heavy metal detoxification gene pathway.