- BALTIMORE (UPI) - A tiny
microbe identified by University of Maryland researchers could be a
powerful
warrior against a persistent and dangerous pollutant.
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- The scientists isolated a strain of bacterium that
successfully
attacks the chlorine bonds of PCBs or polychlorinated biphenyls and slowly
breaks them down.
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- PCBs are suspected cancer-causing agents. They were used
to insulate electrical equipment and transformers during most of the 20th
century but were banned in the United States in 1979.
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- However, 22 years since they were banned, PCBs are still
readily found in river, harbor and bay sediments throughout the world.
Moreover the agent tends to bio-accumulate in the tissue of fish, marine
mammals and humans. This is because PCBs persist years after they were
released and tend to magnify in concentration as they move up the food
chain.
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- The University of Maryland's Center of Marine
Biotechnology
in Baltimore and the Medical University of South Carolina in Charleston
jointly zeroed-in on a bacterium found at a former electrical power plant
in Baltimore where PCB levels were elevated.
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- They then used a DNA screening method to amplify specific
gene sequences in the bacterium responsible for dechlorinating PCBs. The
strain identified is highly adapted to seek out PCBs and "feed
off"
them.
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- "Now we can begin to find ways to use
biotechnological
advancement to address pollution in the environment," said Dr. Kevin
Sowers, research microbiologist at COMB.
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- PCB-contamination remains a serious problem in many of
America's water systems and industrial sites. The finding raises hopes
scientists will soon be able to manipulate bacteria to act as a tool to
clean up pollution.
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- If it proves to be useful for this purpose, environmental
scientists would have a critical new weapon to clean up dangerously
contaminated
industrial sites.
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- At present, PCB-contaminated sediment in rivers, harbors
and streams remains difficult to address. One of the few ways to tackle
the problem is to dredge the sediment and dispose of it in an incinerator
-- an extremely costly undertaking.
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- "It's significant that we know this because once
we know of the bacterium, we can study it and find out how it does the
work," said Dr. Craig Phelps, a microbiologist at Rutgers University
in New Brunswick, N.J. "Then we can encourage other bacteria in the
environment to behave like it."
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- Reported by Koren Capozza in San Francisco
- Copyright © 2002 United Press International
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- http://www.upi.com
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