Edouard Bastarache on wed 29 oct 08
Not only asbestos fibers are pneumotoxic,
Preliminary study says carbon nanotubes look and act like asbestos fibres
Imagine tiny wiry tubes that are about 50,000 times thinner than a single
strand of hair, and stronger than steel. These tiny tubes made of rolled up
sheets of carbon hexagons are better known as carbon nanotubes. They look
and act much like asbestos, according to a recent preliminary study, raising
concerns with researchers.
Nanotechnology involves working at the nanometre scale of small numbers of
atoms to produce materials and devices. It's at the forefront of research
and technology development - and carbon nanotubes are the building blocks.
Most carbon nanotubes are made from sheets of graphite about a nanometre, or
one billionth of a metre wide, and formed into cylinders. Nanotubes are
important in electrical research and the next-generation of computer chips
and are also being developed for use in new drugs, batteries and other
products. However some scientists and environmentalists are concerned that
they could pose hidden dangers.
A recent study showed that inhaling carbon nanotubes in sufficient
quantities could be as harmful as breathing in asbestos. During the study,
led by the Queen's Medical Research Institute at the University of
Edinburgh/MRC Center for Inflammation Research in Scotland, scientists
observed that the long, needle-like fibre shape of carbon nanotubes look and
behave like asbestos fibres. The researchers reached their conclusions after
they introduced the needle-thin nanotubes into the abdominal cavities of lab
mice and found that the inside lining of the animals' body cavities became
inflamed and formed lesions.
This resemblance raises the concern that the nanotubes may cause illness
similar to that linked to asbestos. Asbestos can cause mesothelioma, a
deadly cancer of the membrane lining the body's internal organs (especially
the lungs) that can appear 30 to 40 years after exposure. Most people who
develop mesothelioma have worked on jobs where they inhaled asbestos
particles.
Study co-author Ken Donaldson stated, "We still don't know whether carbon
nanotubes will become airborne and be inhaled, or whether, if they do reach
the lungs, they can work their way to the sensitive outer lining. But if
they do get there in sufficient quantity, there is a chance that some people
will develop cancer-perhaps decades after breathing the stuff."
Donaldson also commented on what he deemed to be the upside of the findings.
"Short or curly carbon nanotubes did not behave like asbestos, and by
knowing the possible dangers of long, thin carbon nanotubes, we can work to
control them. It's a good news story, not a bad one. It shows that carbon
nanotubes and their products could be made to be safe."
But Donaldson added that the present study only tested for fibre-like
behaviour and did not discount the potential for carbon nanotubes to damage
the lungs in other ways. "More research is still needed if we are to
understand how to use these materials as safely as possible," he notes.
It is estimated that the market for carbon nanotubes will continue to grow
and could easily reach 1-2 billion dollars annually within the next seven
years, according to studies.
Gis la revido (A la revoyure)
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
Canada
http://www.pshcanada.com/Toxicology.htm
http://www.flickr.com/photos/30058682@N00/
http://pagesperso-orange.fr/smart2000/livres.htm
http://www.flickr.com/photos/potier/20321056/
http://myblogsmesblogs.blogspot.com/
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