By Stephen Leahy

The nascent nanotechnology industry collectively cringed last week after a study showed that fish exposed to nanoparticles suffered brain damage. Critics say the much-hyped multibillion-dollar nano industry has a dark side few want to talk about.

“How many more studies showing toxicity are needed before regulators step in?” asks Kathy Jo Wetter of the Winnipeg-based ETC Group. ETC and other environmental groups are calling for a moratorium on the commercial production of nanoparticles.

Nano products are not subject to any special regulations, in part because little is known about the environmental and health implications of nanotechnology, says Kevin Ausman, executive director of the Center for Biological and Environmental Nanotechnology at Rice University in Houston.

Nanotechnology is a catchall term for an enormous range of research and technology measured at the scale of one-thousandth the width of a human hair. At this very small scale, ordinary materials have extraordinary properties promising the semi-fantastic — supercomputers that fit on the head of a pin and fleets of cancer-fighting nanobots — and the more mundane — better paint and eye shadow.

Stain-resistant nanopants and sunscreens and cosmetics using nanosized titanium dioxide particles are already on the market. And the Nanodesu bowling ball is one of the first consumer products that uses nanoparticles called fullerenes — aka buckyballs — which are extremely stable arrangements of carbon atoms that look like soccer balls.

To see what might happen if buckyballs got into the environment, Eva Oberdörster, an aquatic scientist at Southern Methodist University, put some into a fish tank at a concentration of 0.5 parts per million, along with nine largemouth bass. The buckyball-breathing fish experienced significant brain damage after 48 hours. Brain-cell membranes were disrupted, an affliction that has been linked to illnesses such as Alzheimer’s disease in humans.

Oberdörster’s unpublished study, which was released last week, is one of the few completed studies looking at the potential risks of nanomaterials. There is some cause for concern. Two recent studies documented lung damage in animals after they inhaled a type of buckyball called a carbon nanotube. Another showed that nanoparticles can get into the brain if inhaled.

They’re also small enough to cross cell walls and leak into the nucleus, the home of an organism’s DNA. And, in the case of titanium dioxide nanoparticles, they can kill bacteria. That’s good news in a hospital, but bad news in the environment, where bacteria are extremely important for maintaining soil fertility, among other things.

Understanding how nanomaterials and the environment interact is a complex, interdisciplinary problem, says Ausman.

“Some of the ways we normally measure environmental toxicity aren’t applicable to nanotechnology. And there aren’t many researchers who really understand these novel materials.”

One who does is John Bucher, director of federal toxicology research at the National Institute of Environmental Health Sciences. His group will soon begin a series of studies on the environmental health effects of three types of nanoparticles.

“There are so many different types of nanomaterials, some are likely toxic,” says Bucher.

Sorting out the impacts of nanotech won’t be easy, since the properties of nanomaterials are not well-defined yet. Something such as gold — which is normally biologically inert — is highly reactive and likely to disrupt biological processes when it’s nanosized.

And then there’s the problem of trying to detect particles of such a tiny size, says Bucher. Microscopes powerful enough to identify nanoparticles are just being developed.

It will be several years before the National Institute of Environmental Health Sciences toxicology studies are completed.

Ausman thinks regulations will be needed to guide future applications, but not enough is known to establish these yet. In the meantime, the nano industry and the benefits it can bring society shouldn’t be held back over toxicity fears, he says.

“I’m not concerned at this point.”