(NHI Nanoblog) Carbon nanotubes are rapidly emerging as the most prominent short-term concern in the exploding area of nanotechnology. In a new study, University of California, Berkeley researcher Mark Philbrick proposes one way to protect worker and public safety without waiting until regulators can get their arms around the entire field.
Philbrick’s paper, published in a special issue of the journal Risk Analysis that’s dedicated to nano safety issues, says we need “anticipatory governance” to deal with carbon nanotubes.
In other words, he says, we should treat the material as if it’s harmful until we know for sure that it isn’t — which means not using it without protection, or in ways that could expose people, animals or the environment.
Philbrick said CNTs are basically the poster child for nanotechnology, an amorphous field that uses super-small with super properties to develop new medicines and commercial products.
The carbon tubes, which can be single- or multi-walled, “seem to be able to do just about anything, and at the same time are probably among the most challenging of nanomaterials to characterize,” he said.
Nanotubes are tiny and light. They add strength to the material they’re incorporated into, such as steel. Since they can also insulate and conduct electricity, the cylinders hold great promise for a number of other uses.
Unfortunately, CNTs also behave like fibers — and, because of their minuscule size, can be inhaled and get stuck in the lungs. Although it’s not a perfect comparison, the best analogy is asbestos. The legacy of that material colors the ongoing development of carbon nanotubes.
Philbrick, a researcher at Berkeley’s Center of Integrated Nanomechanical Systems, said the first priority should be to protect workers, an effort which is fairly well advanced. But treating CNTs as if they’re harmful means using common sense to select applications, he said.
Inside an airplane wing? Sure. In a nonstick skillet? No way.
“Given the information we have about carbon nanotubes, it’s probably a really bad idea to use these things in dispersive applications,” Philbrick said. “So don’t put carbon nanotubes in sunscreens, and don’t put them in household cleaners.”
One big challenge for an anticipatory system, he said, is simply getting the information to companies that are making and using carbon nanotubes. Large companies that are used to dealing with dangerous substances are eager to avoid hurting their customers — and generally fine with taking precautions for that reason. But startup firms, which are commonplace in such a cutting-edge field, are thinking more about their next round of funding than the potential side effects, Philbrick said.
“Risk is something they really don’t have a lot of time for,” he said. “It’s not that they’re trying to trash the planet, it’s just not that much on their radar screen.”
Ironically, Philbrick said, there’s enough research on carbon nanotubes that the alarm bells are going off, both in terms of workplace safety and environmental issues. He said he’s more worried about nanoparticles, such as nanosilver and titanium dioxide, that are actually being put into everyday products, such as fabrics and cosmetics, that could release the material into the environment.
Research has already shown that nanosilver can end up in end-stage sewage sludge, raising concerns about water supplies as well.
By contrast, Philbrick said, CNTs have to be produced in a controlled environment, and the lessons of past mistakes such as asbestos have the industry paying attention.
“Carbon nanotubes have gotten enough attention that we’re a lot less likely to do something stupid with them,” he said. “That’s a fairly positive sign.”
