Study Says Effects of Nanotubes May Lead to Cancer
"Nanotubes," microscopic, high-tech devices developed to be utilized in a wide variety of consumer products cause the same kind of harm in the body as asbestos does, according to a study involving mice and it is causing alarm among safety experts in the workplace and for others as well.
Researchers said, the nanotubes, which are used at increasing rates in sporting good, electronic components and dozens of other products, triggered a kind of cellular reaction that over a period of years typically leads to mesothelioma, a fatal form of cancer, within days of being injected into mice.
The study found that only longer versions of the vanishingly small fibers have the toxic effect. Being able to prove that the engineered motes can cause problems when inhaled, which is the way most people would be exposed to them requires further experiments to be conducted.
The justification for urgent follow-up tests and government safety guidance for nano workers is strong based on preliminary evidence alone. Other experts requested labels to guide consumers or recyclers who might be exposed to the material when incinerating or discarding destroyed nanotube products.
Anthony Seaton of the Edinburgh, Scotland Institute of Occupational Medicine, a contributor to the research was quoted as saying "Now we should consider ourselves forewarned and forearmed with respect to nanotubes," in a recent online journal edition of Nature Nanotechnology. "We now know that some nanotubes are likely to cause mesothelioma. It is important that those kinds of substances be treated carefully."
This latest research is being released at a critical time in the science, business and regulation of nanotechnology, a new field that holds much promise and involves the creation of particles that are just a few billionths of a meter in size.
Such minute pieces of material behave in a very different manner than larger pieces comprised of the same substance. Nanotubes made of carbon atoms conduct electricity easily while some kinds of carbon, especially those in chunks do not. This makes nanotubes useful in materials like computer components that do not handle the buildup of static charge well.
It is expected that Nanotubes alone will be a $2 billion industry within the next few years. Companies around the globe have begun pumping out thousands of tons of nanomaterials per year, including nanotubes, spherical nanoscale "Buckyballs" and other engineered items called quantum dots, which may result in promising breakthroughs in medical diagnosis.
Because of their size, they can cause very different health and environmental risks to, yet they are currently being regulated on the basis of what they are made of which is "carbon." This is causing concern among some groups.
Federal spending to support the fledgling industry significantly outweighs the amount of government money allocated to researching the environmental and health impacts of nanomaterials. Congress is currently wrestling with this issue as it prepares to reauthorize the National Nanotechnology Initiative, which has pumped approximately $1.5 billion a year into research, with health and safety initiatives receiving only about 5 percent of that money.
Andrew Maynard co-author of the new research report and member of the Project on Emerging Nanotechnologies in Washington, said, "We've got to invest in the right research and really fast. We have to put a strategy in place. No matter what the government says, there is no clear vision of where to go or how to get there."
Ken Donaldson of the MRC/University of Edinburgh Centre for Inflammation Research led a new study to track the short-term effects of injecting various kinds of carbon nanotubes and asbestos fibers into the animals' abdomens, near the mesothelium, which is tissue surrounding the lungs and other organs. Asbestos fibers tend to migrate to the mesothelium after being inhaled. Granulomas, early cellular changes that can eventually lead to cancer were caused by the longer nanotubes.
Donaldson said, "We need more information about workplace exposure and these materials." Maynard added, unfortunately, scientists still have not agreed on the best method for measuring airborne nanotube dust levels.
A professor who heads the University of Vermont's environmental pathology program, Brooke Mossman, said she was not persuaded by the experiment, primarily because no one knows if the injected doses were reflective of realistic conditions and because the nanotubes were not inhaled, they were injected.
Mossman also said that granulomas often form in response to irritants and does not necessarily portend cancer. "The system is very artificial making it hard to evaluate exactly what to make of this," she said.
In a media briefing, Seaton countered that granulomas always progress to cancer when formed by fibers in the mesothelium.
The head of the Center for Biological and Environmental Nanotechnology at Rice University, Vicki Colvin, said that even though the research says "that we should be handling these materials with a great deal of caution," it was her understanding that the majority of manufacturers are already using adequate protection including gloves and masks. She said, "I believe control measures are being taken very seriously."
She agreed with others, however, that because the industry has been less than forthcoming about what exactly it is making and the processes being used, that little is really known about the risks that the public and workers may experience.
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