Nanotechnology may well be one of the most talked about industries of the last few years. Predicted to value US$173.95 billion globally by 2025, this fast-moving sector is already delivering major sustainability, health and well-being benefits to society.

Nanomaterials, as the name suggests, are very small, less than a millionth of a metre in size. They have unique physical and chemical features which give them improved properties such as greater reactivity, strength, electrical characteristics and functionality. These benefits have resulted in nanomaterials being incorporated into a wide range of consumer products. The automotive, computing, electronic, cosmetics, sports and healthcare industries all benefit from nanotechnology innovations. New fields have also emerged, such as nanomedicine, which aims to dramatically improve our future ability to treat disease.
But exciting as this may sound, as with any innovation, we must ensure that human health and environmental impacts are considered. And this is not a simple task. Although standard hazard assessments are available for a wide range of things – such as chemical compounds – nanomaterials have unique properties so cannot be evaluated in exactly the same way.

Environmental health and humans

Nanomaterials are already entering our environment, albeit at low levels. They are being found in waste water from products like toothpaste, sun lotion, and when items such as nano-silver socks (which prevent smelly feet) are washed. Short-term environmental safety studies have also found that many nanomaterials adsorb (form a thin film) on the surface of organisms’ – such as algae and water fleas – epidermis. The materials are also distributed in both gut systems and throughout small creatures’ bodies.

It is vitally important we get to grips with the potential adverse impacts of nanomaterials before widespread environmental dispersion occurs. At present, the long-term effects of nanomaterial exposure on ecosystems is poorly understood. Nor do we know the impact of nanomaterial exposure on the food chain. They could affect feeding rates as well as the behaviour and survival of different species, for example.
We also don’t know enough about how nanomaterials can affect humans when exposed in small doses and over long periods. The most important routes of exposure for humans are the lungs, gut and skin. Nanomaterials are being incorporated into food products and packaging, and they may be inhaled or swallowed by workers during manufacturing, too. Tests have shown that once nanomaterials enter the body they become trapped in the liver, but we don’t know what risk they pose long term.

The current standard non-animal safety tests for human lung, gut and skin exposure are very simplistic. For example, to determine the biological impact of inhaling nanomaterials, scientists grow a single lung cell system in the lab and expose it to nanomaterials suspended in liquid. But there are over 40 different cell types within the human lung. These kinds of tests cannot accurately predict the potential harm associated with nanomaterial exposure. Nor accurately mimic the complexity of the human body or the manner in which we encounter nanomaterials.