Risks from working with Nano Technologies
The prefix ‘nano’ means dwarf, and a nanometer is 10-9 of one metre. And that, for the experts, is teeny tiny. see image:
Nanotechnology is defined as the
‘design, characterisation, production and application of structures, devices and systems by controlling shape and size at nanometre scale’.
In late October 2011, the European Commission adopted a recommendation on the definition of nanomaterial:
“Nanomaterial” means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm.
In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.
By derogation from the above, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials.”
Nanotechnology has the potential to lead to the development of a broad range of new materials that are widely portrayed as bringing huge benefits to society, from novel medicines that effectively target the site of disease or infection to techniques for bringing clean water to underdeveloped societies and combating global warming. Many believe that nanotechnologies have the potential to:
- deliver improvements for consumers
- help to sustain continued recovery and growth in the manufacturing industry, and
- contribute to the effort to tackle global challenges
One inventory of nanotechnology-based products now lists 1,317 consumer products, produced by 587 companies, in 30 countries; the largest class is ‘Health & Fitness’, totalling 738 products, many of which are cosmetics and sunscreens.
Hazards and Risk
There are a huge variety of nanosubstances which vary in size, shape, surface chemistry and coating means that, even for one chemical type such as titanium dioxide (one of the most prolifically used nanomaterials already on the market). The number of possible forms of nanoparticles is large, which complicates the health and safety risk assessment needed to protect workers (and the public) who use nanomaterial’s or products that contain them.
The nature of the hazards and controlling them in the workplace might need a single assessment of each form, or, an understanding of the different physical and chemical properties which might affect health negatively in the workplace.
Why Use Nanoparticles?
The benefits of nanotechnology are due to the novel properties that these materials bring.
As the size of a particle decreases, the surface area per unit mass increases, with more atoms on the surface of the particle and increased surface reactivity. Furthermore, the number of particles per unit mass increases exponentially with decreasing size.
There is also the potential for generating novel structures such as nanotubes and fullerenes (or buckyballs), which are tubes or hollow spheres of carbon atoms linked in hexagonal and pentagonal arrays. Such considerations have led to the thought that nanoparticles may have different toxicological properties and different hazard potential from their larger counterparts.
Health Effects of Nano-Particles
There have been a large number of investigations into nanoparticle use. Some animal studies show that the particles contribute to inflammation and lung injury, after inhalation. Also, some nanoparticles may have genotoxic effects and induce DNA damage.
Research has mainly focussed on the potential toxicity of nanomaterials in the lung and skin, as well as the likelihood of their transport to other organs. But effects such as clots and heart attacks could be possible too. It has also been suggested that nanotubes might induce similar health effects to asbestos.
As a result, the European Commission and the Health and Safety Executive recommend that ‘nanosciences and nanotechnologies (N&N) research activities should be conducted in accordance with the precautionary principle,
‘anticipating potential environmental, health and safety impacts of nano technology and nano materials (N&N) outcomes and taking due precautions, proportional to the level of protection, while encouraging progress for the benefit of society and the environment’,
although there remains some debate about how the precautionary principle can be applied in this case.
To control exposure to nanomaterials in the workplace, the most effective approach is to enclose anything that processes these. A well designed, properly installed and used ventilation and exhaust systems can provide adequate protection for workers. Also, consider monitoring and maintenance to avoid leakages and breaches from air filters. Filtration of the exhaust systems with multi-stage high-efficiency particulate air filters is recommended by the HSE.
Personal protective systems as used for other hazards, e.g., respiratory masks, have not yet been fully tested. Although, diffusion, mechanical filtration and electrostatic attraction are potentially effective against nanoparticles.
One of the most important strategies is to know that nanomaterials are being handled; this is straightforward for dedicated nanomaterials’ facilities, where the materials are, for example, is manufactured. However, organisations lower on the supply chains may not be fully aware of the components of materials.
There is uncertainty about the hazards and risks to workers using nanomaterials in the workplace. So proceed with caution.
Further Advice and Reading
- HSE: Nanoparticles in the workplace
- Wikipedia: Nanotechnology
- Adapted from ‘Risk perception and risk communication with regard to nanomaterials in the workplace’ – European Risk Observatory. Available in full from the European Agency for Safety and Health at Work