Scientists say carbon nanotubes could be as dangerous as asbestos

Tiny carbon nanotubes, which scientists have considered to be potentially important in future development of technology, might be as dangerous as asbestos. A new study, published in Nature Nanotechnology this week, has found that longer threads of carbon nanotubes share some of the same properties as asbestos, including the ability to cause disease. The study was carried out on a collaborative basis by researchers at British institutes and a U.S. based Project on Emerging Nanotechnology. The research involved injecting mice with asbestos or with samples of various sizes of carbon nanotubes. When the scientists examined the lining of the abdominal cavities of the mice, they found that longer carbon nanotube strands caused the same types of inflammation and lesions that were caused by asbestos fibers. Carbon nanotubes are currently available for sale, but the authors of the study say they are not certain the extent that the materials have already been used in industrial materials and consumer products such as electronics. Carbon nanotubes, the researchers say, are expected to eventually be used in composite metal structures and in consumer electronics, among other products. However, while the uncertainty over the extent of the use of carbon nanotubes still exists, the authors of the study hope that exerting pressure on companies which are developing products and technologies that use the nanotubes will prompt them to release details about the types of nanotubes they are using. Andrew Maynard of the Project on Emerging Nanotechnologies, one of the authors of the study, says that their discovery of the potential dangers of the nanotubes “ups the stakes.” But Vicki Colvin, director of the National Science Foundation-funded Center for Biological and Environmental Nanotechnology, says the potential benefits of carbon nanotubes are too powerful to ignore, and that the research simply emphasizes that it’s important to make sure that companies developing nanotechnology “know how to handle it.” One potential application of carbon nanotubes is the development of cars which are up to eighty percent lighter than current vehicles but are no less durable or sturdy. The authors of the study say that more research is needed before they can definitively say that the carbon nanotubes act just like asbestos fibers. There are some major limitations in their research that prevent them making the conclusion that the nanotubes are equal to asbestos in terms of toxicity. One difference, for example, is that they injected the materials into the mice instead of allowing them to inhale or otherwise ingest the materials naturally. In addition, the scientists ended the experiments after only one week, which is not long enough to determine whether or not mesothelioma would have developed in the mice exposed to carbon nanotubes. In humans, mesothelioma takes three to five decades to develop; in the mice, however, it would have shown up within one to two months. Another important limitation in the study is that the toxic effects were noted only with longer nanotubes. The shorter tubes did not cause any toxic effects in this study. This means that the problem may be in the way the materials are constructed and used, rather than inherent in the materials themselves. Andrew Maynard says the results of the study show that “there are no simple answers here.” (Source: Asbestos and Mesothelioma News)