The Big Risk of Small Particles: The Threats and Promise of Nanotechnology

Article excerpt

Skin cancer is reaching epidemic proportions in Australia. SA combination of long, blistering summers and increased exposure to ultraviolet radiation from the depletion of the ozone layer has pushed up the number of sufferers. Health-care providers delivered over 412,000 treatments for non-melanoma cancer in 1997. In 2010, that figure hit 767,000, the Australian Medical Journal reported last year. By 2015, treatments are likely to top 900,000. The graphs for melanoma cancer are also trending upwards.

Not surprisingly, sunscreens are high on the list of defenses among a nation that prides itself on an outdoor lifestyle. But now some Australians would prefer to go without that protection because of a novel ingredient manufacturers are adding to their creams: nanotechnology.

Industry studies say replacing traditional "bulk" zinc oxide products, which filter UV radiation, with their nano counterparts makes sunscreen both transparent and more effective. The health risk is negligible, they say. In fact, well-publicized research conducted in 2010 by Australia's science agency CSIRO said that sunbathers using nano-enhanced sunscreens might even enjoy health benefits from marginally increased zinc levels.

But Australians have been hard to convince. And many non-governmental organizations (NGOs) have sided with the skeptics. Last year, for example, Friends of the Earth, an international network of environmental activist groups, called for stronger regulation, clear product labelling and other measures that would effectively ban the use of nano applications from sunscreens. The document ("Nano ingredients in sunscreen, the need for regulation") cited research that suggested nano zinc oxide could increase cancer risk for users and, worse still, cause damage to DNA.

Nanotechnology Risks

"Until risk assessment for nanomaterials is validated and fit-for-purpose detection methods are developed, we do not support the commercial sale of nano-sunscreens," said Georgia Miller, the author of the report.

There have been similar arguments about nanotechnology in other fields. Five years ago, it was nanosilver. In 2008, an alliance of health and environmental campaigners filed a petition with the U.S. Environmental Protection Agency (EPA) against manufacturers of nanosilver products. It argued that the substance, which is used in washing machines, among other things, could increase the toxicity of waterways.

Before that, it was carbon nanotubes, which are used in medical equipment, building materials, sporting goods and vehicles but may also have the potential to cause cancer. And in 2003, the U.S. Congress became embroiled in a bitter fight about the definition, uses and risks associated with such technologies. Everywhere it is found, this tiny technology seems to cause trouble.

New Risks, New Rules

Nanotechnology refers to the study and application of materials at the atomic and molecular level, specifically anything smaller than 100 nanometers. (A nanometer is one-billionth of a meter--to put this in perspective, a sheet of paper is about 100,000 nanometers thick.) One of the reasons that the risks and benefits of nanotechnology are so hard to pin down is that it does not exist as a single thing. Calling them "nanotechnologies" would be mote accurate.

Modern engineering techniques often work at the atomic level, so when products hit the supermarket shelves or enter the industrial supply chain, they are nanotechnologies by default. Those manufacturing processes cut across all sectors--from medicine, computing and cosmetics to energy, plastics and electronics. Sometimes, scientists working on the same product call it by different names because the processes are so new that they may be working in ignorance of each other's research.

Risk is also difficult to assess because many nanomaterials act in unique ways. Nanosilver, for example, has a much higher surface area than traditional forms of the metal. …