Bacteria hold great promise for cleaning up contaminated soils and water sources, says Flynn Picardal, PhD, an associate professor of public and environmental affairs at Indiana University.

Dr. Picardal has been working to isolate bacteria capable of breaking down polychlorinated biphenyls (PCBs), a class of toxic organic chemicals found in some industrial wastes. He now holds a patent on several strains of bacteria that can destroy hard-to-degrade PCBs in waste water, sludge and sediment.

“Bacteria have been successfully used to clean up oil spills and degrade petroleum products, but it is harder to find bacteria that can manage man-made chemicals like PCBs because they haven’t had time to evolve alongside these new compounds,” Dr. Picardal says. “What we’ve been able to do in the lab is to isolate those few bacteria that can grow on different types of PCBs in the hope that they can be utilized as a tool for remediation.”

Bacteria may also be useful in controlling substances that cannot be broken down, he notes.

“In the case of contamination from metals and radionuclides, we are dealing with elemental substances that cannot be broken down any further,” Dr. Picardal says. “Although we can’t destroy these elements, we may be able to utilize bacteria that will immobilize them so they stay in the soil instead of migrating into groundwater.”

The one obstacle to the growth of bioremediation technologies is bacteria’s poor public image.

“People typically think of bacteria in terms of disease,” Dr. Picardal says, “but only a small percentage of bacteria are harmful to human health. The vast majority perform vital environmental maintenance. Our existence really depends on bacteria, and our ability to clean up toxic environmental waste is going to depend on them, too.”

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