What's the problem?

Nanotechnology is already used in a range of products (see "Nanoproduct list"). However, knowledge about the potential health and environmental impacts of some uses of the technology lags well behind their commercial application.

In its 2008 report on nanotechnology, the UK’s Royal Commission on Environmental Pollution concluded there’s a “plausible case for concern" about some classes of nanomaterials. A major conclusion of this report is that nanomaterials are hugely variable in their nature and we don’t yet know enough about how they behave. Gold, the Commission points out, is inert in its natural form but becomes highly reactive when reduced to two to five nanometres.

It's the so-called “free nanoparticles” (such as those found in cosmetics) that the Commission says are likely to present the most immediate risks. Fixed nanoparticles in solid objects such as computers and phones have attracted less attention, though they may also pose a risk as the product degrades.

Health and environmental risks

Free nanoparticles are of particular concern to human health because they could enter the body through the lungs, skin or intestinal tract. What's not known is how long they’ll remain there, how much damage they may cause, and at what dose.

In the case of sunscreens containing nanoparticles, healthy skin is thought to provide an effective barrier – but there are unanswered questions about whether they can penetrate skin that’s broken because of sun damage, eczema, acne or wounds.

There are also significant unknowns about the effect of nanoparticles on the environment. Products containing nanosilver, which is used for its antibacterial properties, are a major issue. Silver is known to be highly toxic to aquatic life; the Royal Commission on Environmental Pollution has fingered the use of nanosilver as a key concern.

In our March 2007 test of washing machines we tested a Samsung Silver Nano Health System J1255AV that used nanosilver particles as part of its washing action. We voiced our concerns then about the use of this technology and have seen no reason to change our view. You can get clean and sterile washing without using nanoparticles.

"Anti-ageing" creams

Dr Brandt's Lineless Cream, available in shops here, claims to contain anti-ageing fullerenes. Fullerenes are tiny hollow carbon balls: the smallest one is called C60 and measures a mere nanometre across.
 
The US consumer organisation Consumers Union asked Harold Kroto and Robert Curl, who shared the 1996 Nobel Prize in chemistry for constructing C60 fullerenes, whether their discovery should be used in cosmetics.

“I wouldn’t put C60 on my skin,” Kroto said. Curl agreed, saying he wouldn’t expose himself “to a new substance for essentially trivial reasons".