Last Tuesday, international researchers reported that
certain types of long, thin carbon nanotubes may, if inhaled, pose a cancer
risk similar to that of asbestos. Long, thin carbon nanotubes pose the greatest
danger during the manufacturing process, when dust-like particles in the air
could be inhaled by workers. This exposure could lead to lung cancer later in
life, claims Andrew Maynard of the Woodrow Wilson International Center Scholars
in Washington,
D.C.. Once finished, carbon nanotubes
pose less of a health risk because they are embedded in other materials.
What are Carbon
Nanotubes?
Carbon nanotubes are molecular-scale structures made from
carbon graphite,an incredibly strong and lightweight material. They are used
for electronics, drug development, lightweight building materials, aerospace
applications, structural engineering projects, and many other purposes. Since
their discovery in the early 1990s, scientists have been concerned that carbon nanotubes
(like asbestos) would adhere to the outer lining of the lung – the mesothelium.
Asbestos and
Mesothelioma
Mesothelioma is a disease which causes cells of the
mesothelium to become abnormal and divide, thus damaging tissues and organs. Today,
more than 90% of mesothelioma cases are linked to asbestos exposure. Widespread
asbestos exposure is considered to be the worst occupational hazard in the
history of the United States.
Asbestos, and potentially carbon nanotubes, are harmful because their fibers
can penetrate deep into the lungs.
Why Shorter Carbon Nanotubes
are Safer
Researchers at the University of Edinburgh
took three groups of mice and injected them with carbon nanotubes at least 20
microns long and several atoms thick, shorter nanotubes, or asbestos fibers.
After 24 hours, the mice that received the asbestos fibers and longer nanotubes
showed inflammation – the first step in the cancer process. A week later, mice
from the afflicted groups showed scar-like tissue buildup. This buildup is known
as granuloma, another step in the process. Mice who received the shorter,
thinner nanotubes were unaffected. Researchers believe that the fibers in the
shorter tubes were small enough to be ingested and ejected by immune cells.
The NanoBusiness Aliance
Responds
Sean Murdock, head of the NanoBusiness Alliance says that
precautions have already been implemented in many factories. "The good news is
that we're understanding the potential hazards before we have large-scale use
of these products (now) and not four decades later", he said.
Resources:
http://www.latimes.com/features/health/la-sci-nano21-2008may21,0,4559970.story
http://seattletimes.nwsource.com/html/nationworld/2004428074_nano21.html?syndication=rss
http://www.insurancejournal.com/news/national/2008/05/21/90207.htm
http://timesofindia.indiatimes.com/HealthSci/Carbon_nanotubes_bad_as_asbestos/articleshow/3060202.cms
http://en.wikipedia.org/wiki/Mesothelium
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Re: Carbon Nanotubes May Pose Cancer Risk
