Nanomaterials are tiny particles, invisible to the human eye, and they are present in products such as food, cosmetics, electronics and medicines.
Nanomaterials are present naturally in, for example, volcano emissions, or can be by-products of human activities, for example diesel exhaust fumes or tobacco smoke. But of particular interest are manufactured nanomaterials, already found in a very wide range of products and applications.
European Agency for Safety and Health at Work has been concerned about the consequences on the health of workers exposed to nanomaterials.
The most important effects of nanomaterials have been found in the lungs and include among others inflammation and tissue damage, fibrosis and tumour generation. The cardiovascular system may also be affected. Some types of carbon nanotubes can lead to asbestos-like effects. As well as the lungs, nanomaterials have been found to reach other organs and tissues including the liver, kidneys, heart, brain, skeleton and soft tissues.
As a result of their small size and large surface area, particulate nanomaterials in powder form may present risks of explosion, whereas their respective coarse materials may not.
What are nanomaterials
Nanomaterials are materials containing particles with one or more external dimensions between 1-100 nanometres (nm).
Up to 10 000 times smaller than a human hair, nanomaterials are at a size comparable to atoms or molecules and take their name from their minute structures (a nanometre is 10-9 of one metre).
Not only because of their tiny size but also because of other physical or chemical characteristics that include, amongst others, their shape and surface area, nanomaterials differ in their properties from the same materials at larger scales. Because of these differences, nanomaterials offer new and exciting opportunities in areas such as engineering, information and communication technology, medicine and pharmaceuticals, to name but a few.
Some such nanomaterials have been used for decades such as synthetic amorphous silica in concrete, tyres and food products. Others have only more recently been discovered, such as nano-titanium dioxide as a UV-blocking agent in paints or sunscreen; nano-silver as an anti-microbial in textile and medical applications; or carbon nanotubes, widely used for their mechanical strength, light weight and heat-dissipation properties and electrical conductivity in applications such as electronics, energy storage, spacecraft and vehicle structures and sports equipment. New generations of nanomaterials continue to be developed rapidly and the market for them is expected to grow.
Although nanomaterials have many beneficial properties, there are large gaps in our knowledge about their associated health hazards. Particular care regards the management of these materials must therefore be taken while research continues.
Health effects of nanomaterials
The Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) found that there were real health hazards associated with a number of manufactured nanomaterials.
Not all nanomaterials necessarily have a toxic effect, however, and a case-by-case approach is necessary while ongoing research continues.
Workers may come into contact with nanomaterials at the production stage. However, many more workers may be exposed to nanomaterials at different stages of the supply chain, where workers may not even know that they are in contact with nanomaterials; consequently, it is unlikely that sufficient measures are being put in place to prevent exposure.
Exposure may therefore occur in a variety of occupational settings where nanomaterials are used, handled or processed and consequently become airborne and can be inhaled, or come into contact with the skin; for example, in contexts ranging from healthcare or laboratory work to maintenance or construction work.
The EU legislation
Of particular relevance are the Framework Directive 89/391/EEC, the Chemical Agent Directive 98/24/EC, and the Carcinogen and Mutagen Directive 2004/37/EC, as well as the legislation on chemicals (REACH and CLP ). It means that employers are required to assess and manage the risks of nanomaterials at work.
If the use and generation of nanomaterials cannot be eliminated or substituted by materials and processes less hazardous, worker exposure must be minimised through prevention measures following the hierarchy of control giving priority to:
1. Technical control measures at the source
2. Organisational measures
3. Personal protection equipment
Although many uncertainties remain, there are high levels of concern about the safety and health hazards of nanomaterials. Therefore, employers and workers must apply a precautionary approach to risk management and the choice of prevention measures.