(NHI Nanoblog) One of the biggest challenges facing scientists, academics and policymakers exploring the pros and cons of manmade ultra-small particles is explaining to the general public what’s potentially dangerous — and what’s not. Steffen Foss Hansen has come up with a simple idea: Turn a complex risk-assessment matrix into a series of dots that suggest green for safety, yellow for caution, red for avoidance and gray for the unknown.
Hansen, a postdoctoral researcher at the Technical University of Denmark, calls his system “NanoRiskCat.” He envisions five dots: The first three cover exposure risks (to professional end users, to consumers and to the environment), while the second two indicate potential effects (to humans and to the environment). Each nano-sized material, such as titanium dioxide or carbon nanotubes, is run through an analysis that helps evaluate the risk factors.
For example, a nanomaterial that’s embedded in a solid material would probably get a green dot, for being relatively low risk; a particle that’s part of a structural element, such as concrete, might get a yellow dot because it could potentially escape. Airborne particles would get a red dot, since many studies indicate that inhalation is a cause for concern.
The effect dots consider what’s known about each material’s impact.
The end result is an easy-to-understand set of symbols that could serve as a complement to a required label. Hansen offered two examples during a presentation at last week’s Fifth International Symposium on Nanotechnology, Occupational and Environmental Health in Boston: sunscreen with nano-sized titanium dioxide, and a baseball bat strengthened with carbon nanotubes.
The sunscreen, since it contains a nanoparticle suspended in a liquid, would get three red exposure dots. Since some studies show the substance could trigger health problems in humans, it would get a red dot for risk to people — and a red dot for environmental exposure above a certain concentration.
The bat, on the other hand, would be rated green for exposure risk, since the nanotubes are less likely to be released. On the effects, side, however, the dots would be red, since exposure to carbon nanotubes is associated with lung inflammation and, potentially, other serious problems.
Hansen said NanoRiskCat is now under consideration at the Danish equivalent of the U.S. Environmental Protection Agency, which will decide whether to use it. Companies that make the nano-enabled products would provide the information for the dots, he said.
Nanotechnology leverages super-small particles (a nanometer is a billionth of a meter) to create products with remarkable 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 have lots of potential for a wide variety of applications. But shrinking these substances can change their properties; scientists are struggling to figure out whether, how and why that shift can make them dangerous in the process.
The uncertainty makes things tough for consumers, since many products that could contain nanoparticles (such as sunscreens) don’t say that on the label. Other products that are touted for their nano-enable powers don’t offer a lot of information about what’s inside.
Hansen’s dots were just one of several ideas presented at the conference as simpler ways to present the costs and benefits of nanotechnology. One thing the system doesn’t do is address the potential hazards to workers who make the nano products.
But it does distill a complicated subject into the simple visual language of a stoplight — a guide that’s a big step forward for consumers hungry for better information.