Small Stuff, Big Trouble

There´s nothing tiny about the international controversy brewing over the safety of nanomaterials. In April, a German company recalled a tile sealant called Magic Nano after dozens of consumers suffered breathing problems while using it. Never mind that the product contained particles too large to actually count as nanomaterials (which must be smaller than a billionth of a meter)-the scare was on, and European confidence in products labeled â€nano†had already sunk. In the U.S., trouble ramped up in June when an EPA study found that titanium nanoparticles commonly used in sunscreens cause neurological changes in mice. Since then, at least eight organizations, including Friends of the Earth and The International Center for Technology Assessment, have called for safety assessments of 116 personal care products on the US market, many of which required no FDA approval before hitting the market.

But is nanotech getting an unfairly bad rap? Manipulation of materials at the nano level has potentially ground-breaking applications for medicine, for example (click here for examples from our Future of Medicine slideshow), and some scientists worry that one of the industry's biggest challenges will be overcoming its PR problem.

To get to the heart of the issue, we talked to two experts on opposing sides of the debate. Hope Shand, research director of Ontario-based human rights organization ETC Group has called for a worldwide moratorium on nanotech until the full scope of the technology, and its risks, can be understood. Christine Peterson is founder and VP of Public Policy for the Foresight Institute, a think-tank in Menlo Park, CA dedicated to the beneficial implementation of nanotechnology. Here, they face off about the big picture of this small-scale science.

ARE NANOMATERIALS DANGEROUS?

Christine Peterson:

Not necessarily. It depends on the specific material. There are, of course, concerns that the small size will allow certain particles to pass through barriers such as the skin or lungs. From the research done so far, it isn´t clear that just because something is small enough to penetrate a barrier, it necessarily will. However, other research has found that certain nanoparticles can and will pass between the blood-brain barrier, which could be harmful. Materials act differently at the nanoscale, and you can´t just assume that they´ll be as safe as they are at the macroscale. Gold, for instance, is highly reactive at the nanoscale.

Hope Shand: We don´t know for sure. What we do know is that there´s a virtual consensus among scientists that the toxicology of engineered nanomaterials is largely unknown. That is, while the materials used in creating a nanomaterial may play a role in determining toxicity, it seems that the size of the nanomaterial plays an equal or even more important role. The reason for this is because the smaller the particle, the higher the percentage of atoms on the surface; a high percentage of surface atoms corresponds to a high level of reactivity. In general, the more reactive a substance, the more toxic it becomes.

DOES THE PUBLIC´S PERCEPTION OF THE SAFETY OF NANOMATERIALS MATCH REALITY?

CP:

A small segment of American society is perhaps over-concerned about the dangers of nanoparticles, while the vast majority are paying no attention at all. The activists who did the sunscreen press conference are the ones who are most interested, and their views may be a little exaggerated. The general public is totally unconcerned and that´s perhaps a little too easy-going of an attitude. The right answer lies somewhere in the middle, as some of these materials are going to end up being a problem and some are not.

HS: I believe that people are largely in the dark about this issue. That being said, by allowing nano-products to come to market without public debate or regulatory oversight, government and industry are jeopardizing nanotech´s future.

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