Expert: Nanotech Fears 'Overblown'

Dec. 1, 2006 — Fears about nanotechnology may be overblown, says an Australian expert in toxicology and environmental health.

Monash University's Professor Brian Priestly, director of the Australian Center for Human Health Risk Assessment, says we need to put fears about the potential health risks of nanoparticles into perspective.

Priestly was among a number of nanotech specialists who spoke about nanotoxicology at the Australian Health and Medical Research Congress in Melbourne this week.

Priestly said it's unlikely that members of the general public will be exposed to nanoparticles.

"What we have to ask is what are the chances that we will be exposed to these very fine manufactured nanoparticles, because risk is really a function of toxicity and exposure," he said.

"These things may have slightly higher grades of toxicity than larger particles but a lot depends upon whether we're exposed to them and how we're exposed to them.

"If they get into the air and we inhale them, yeah, they're likely to present the same sorts of risks we have with other types of air pollution of very fine particles."

The majority of nanoparticles will be safe because they're fixed in surface coatings, Priestly added.

Kelly BéruBé, a lecturer in cell biology at Cardiff University in Wales, disagrees. BéruBé has been studying nanosized products of combustion like soot and coal ash as a model for engineered nanoparticles.

People have been exposed to these particles for as long as we have been burning things, she said, and it's known they can cause inflammatory responses and cardiac problems.

She said these are the sorts of particles we should be worried about, rather than engineered nanoparticles.

"These are the ones that everybody's exposed to every day. It's highly unlikely that the average person like you or I is going to be exposed to any of these engineered ones," she said.

Nanoparticles are already used in a wide range of commercially available products including sun screens, cosmetics, shoe polish, crayons and even tennis racquets.

But Paul Wright, a professor in immunotoxicology at RMIT University in Australia, says rapid recent developments highlight the need for caution.

"(Nanoparticles) can have totally unknown effects on the biological system," he said.

Because of their size, nanoparticles can evade the body's normal respiratory and immune defences and once inhaled or absorbed through the skin, potentially finding their way into the nervous and circulatory systems and becoming deposited in organs including the brain.

BéruBé said until we have microscopes powerful to actually track where nanoparticles are going in the environment and in our bodies, and what they actually do there, the jury must remain out about any pending health catastrophe.

"We don't have the technology there to see exactly what these particles are doing, so we can't tell you exactly what the health impacts will be," she said.

"Unregulated use [of nanoparticles] could open society up to the asbestos of the 20th century. But we've been living with [combustion-derived nanoparticles since caveman times and we've learned to adapt to it," said BéruBé.