Toxicity and Safety

Manufactured and engineered nanomaterials are used in a diverse range of applications including personal care, consumer products, healthcare, electronics, photonics, biotechnology, pharmaceuticals, agriculture. The diversity of these applications provides a potential for human exposure via the dermal, oral and inhalation routes, dependent upon the nature of the nanomaterial, the product, its use and disposal. Such diversity when combined with the often novel physico-chemical behaviour of nanoparticles may result in effects on health or the environment being much more wide-ranging than with other substances.

Since the publication of the Royal Society/ Royal Academy of Engineering Report in 2004, there has been intense international effort to investigate the toxicity of nanoparticles, with a significant contribution being made by IOM researchers. Whether or not specific particles will cause heath effects relates to their intrinsic toxicity and the level of exposure. Like all chemicals however the actual toxicity will depend on composition of the nanoparticle and the dose i.e. how much is absorbed by the individual and the system. But for nanoparticles and nanotubes, there are four specific issues which give rise to concerns about toxicity. Nanoparticles have a much higher surface area than the equivalent mass of larger particles, a property which has been shown to relate to toxicity. Because of their small size, some nanoparticles can cross biological barriers such as cell walls and reach and parts of biological systems inaccessible by other larger particles. Some nanoparticles, such as some types on carbon nanotubes, have characteristics (high aspect ratio and durability) which are similar to asbestos and so if inhaled, may give rise to similar heath issues. Lastly, as the rationale for developing nanomaterials is that they will have new and different properties, it is clearly conceivable that these new properties could include altered toxicity.

Whilst there is an extensive programme of work underway to investigate these issues for a wide range of nanoparticles, definitive answers are not yet emerging.