Nano-technology has increasingly made its way into the cosmetics industry. The effect of the use of nanoparticles in cosmetic compounds we apply to our skin, including sunscreen, is creating concerns related to human health and environmental issues.

Nanotechnology involves the creation of compounds that are incredibly small; measuring  under 100 nanometers. To put that in perspective, a human hair is around 100,000 nanometers wide, so we're talking about substances less than one thousandth the width of a human hair.

The use of nanocosmetics means that the cosmetic isn't just sitting on your skin, but can penetrate much deeper.

Due to a lack of regulation in most countries, the cosmetics you use may contain nano-materials and this may not be noted on the label. Nano-technology is not only being used in cosmetics, but also in sunscreens. Given that our governments promote the use of sunscreen to prevent skin cancer, this is worrying indeed.

The world’s oldest scientific organization, the Royal Society, advised in 2004 that as the possible toxicity of nanoparticles cannot be based on equivalent larger sized particles, they should be classified as new chemicals and undergo a full safety assessment. It's my understanding that no such assessment has been carried out anywhere in the world.

One of the problems of nanocosmetic materials is that many small particles have a combined overall larger surface area than the equivalent weight in non-nano materials; hence, the potential to be a good deal more toxic. Added to this, nanoparticles can be more easily absorbed  by biological membranes, cells, tissues and organs that larger sized particles can't. Once nanoparticles are in the body, they can be easily transported around it.

In relation to the environment, very little research has been done; but ask yourself this - where do cosmetics and sunscreens usually wind up? We usually wash them off. Given the minute size of these particles, they can easily pass through any filtering system to wind up in our waterways and ultimately affect the entire food chain.

Exposure to nanoscale aluminum, which is used in sunscreen, has already been found to retard the growth of roots in a number of plant species. Carbon fullerenes, used in some facial creams and moisturizers, have also been found to kill water fleas and bacteria (bear in mind that some bacteria are good).

There's just so much we don't know about the broader effects of nanocosmetics on humans and the environment. It's reminiscent of the days when asbestos was used extensively and took so many years for the dangers to be exposed.

Given there's an element of doubt, are you still happy to use cosmetic products containing nanoparticles? Do you know if any are in your sunscreen, face cream and other cosmetics? If you're not sure, call the company and asked them the pointed question: "Does X contain nanoparticles?"

Better still, why take the risk that the company will be truthful? Perhaps consider switching to a well known environmentally friendly cosmetic range.