Consultant: Nano Products Need Risk “Categories”

(NHI Nanoblog) Much of the focus in the debate over toxicity and testing in the world of nanomaterials is on how researchers can tackle the seemingly impossible task of understanding every single thing that contains these tiny particles and structures.

Donald Ewert has another idea, based on a longtime system used for pharmaceuticals: categories.

“What if we could look at these things and say, ‘Oh, that’s a Category E, that’s a bad one.’ Or, “That’s a Category A, that’s nothing to worry about’?” Ewert asked during a presentation at a recent Washington, D.C. workshop. The event brought U.S. and European Union officials together to push toward concrete action on steps for nano-related safety.

These categories could be similar to those used for drugs, Ewert said in an interview. Low-risk drugs like aspirin or glucose, which are generally dangerous only in unusually large amounts, are at one end, he said. Chemicals that are toxic at only a bit more than the recommended dose, such as Botox and some anticancer drugs, are at the other.

Another example: arsenic is a poison, but in small, controlled doses is used to treat some forms of leukemia.

Categories could work for nano, said Ewert, director of field services for nanoTox, a safety consulting company in Austin, Tex. that specializes in the tiny materials.

Nanotechnology leverages super-small particles (a nanometer is a billionth of a meter) to create products with amazing properties. These materials can make bike frames lighter and stronger and sunscreen more transparent on the skin, as well as new medical instruments and medicines that can save lives.

There is broad agreement that nanomaterials hold great promise for a wide variety of applications. But shrinking these substances can change their properties, and scientists are struggling to figure out whether, how and why that shift can make them dangerous in the process.

Ewert emphasized what many nano watchers repeat: Risk is about the nature of the hazard plus the amount of expected exposure. Even highly toxic substances might be tolerated at ultra-low doses; on the other hand, a material that’s considered incredibly dangerous isn’t risky at all if humans, animals or the environment aren’t exposed to it.

As toxicology work progresses on nanomaterials, he said, researchers are getting a sense for what’s harmful at the molecular and cellular levels. But nobody has a good picture of what happens to the entire human body. An important step forward would be establishing national and international registries to share information, he said.

Ewert’s idea bears some resemblance to what’s known as “control banding,” which assigns different substances and materials to bands that determine exposure limits.

Charles Geraci, coordinator of the Nanotechnology Research Center for the National Institute of Occupational Safety and Health, said during Ewert’s presentation that the concept has merit.

“This is a great tool that has a good opportunity to be applied here,” Geraci said.

Ewert said creating the spectrum could open up the commercialization of products that contain nanomaterials, since it could give companies, regulators and the public more confidence.

“The government does this with airport security,” Ewert said. “We’ll get to that.”

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posted by: alan shalleck on March 25, 2011  12:14pm

This is a very positive idea… but who is to determine what category of risk a nanoproduct falls into?  Here’s an add on idea. Five years ago I proposed a “UL - underwriters laboratory” for nanotech with a total independence that would be funded by industry and government together. It would be the arbiter, after testing, of what goes into which category… and it would, with its testing, develop test categories for clearance that would shorten market introduction. Moreover, the UL for Nano would provide a mark that would be on all accepted or tested products sorted by category of risk. It works for electrical stuff, why not for nanoproducts too.

alan shalleck