Q:
Why are there concerns about the safety of nanoparticles?
A:
People have known for a long time that there are potential health effects which may arise through exposure to particles, for example pneumoconiosis from exposure to coal dust or mesothelioma and lung cancer from exposure to asbestos. In general, the likelihood of illness developing depends on the toxicity of the particle and the level and duration of exposure. Factors which influence the toxicity of particles include the surface area of a particle, how reactive that surface is and where that particle can travel to in the body. Because of their small size, nanoparticles will have a much higher surface area relative to the same mass of larger particles. They are also being designed to have different and in some cases more reactive surfaces. There small size leads to the possibility that they can also more easily cross cell and other boundaries. All of these three factors have led scientists to conclude that some nanoparticles may be more toxic than larger particles of the same materials. Whether this toxicity is at a level to cause ill health will depend on the specific nanoparticle type and the levels and duration of exposure.
Q:
Are nanoparticles safe?
A:
As we commonly think of the term “safe”, some nanoparticles are undoubtedly safe. In each breath we take in a city we breathe in more than 1000000 nanoparticles without any apparent ill-effect. However, safety is not an absolute concept. It depends on the material itself (not all nanoparticles have the same absolute toxicity) and the levels at which people or the environment are exposed.
Q:
Are nanoparticles toxic?
A:
There is no simple answer here. Some nanoparticles, not all, will have a toxic potential which can be measured in toxicology tests. Whether these nanoparticles will pose a risk to the health of people who make or use them will depend on how they are used and the levels of exposure which occur.
Q:
Are carbon nanotubes as dangerous as asbestos?
A:
What makes (some) asbestos dangerous is that the fibres can penetrate deep into the lung and once there they stay, cause inflammation and eventual in some cases cancer. They are not easily removed because of their length (>15000 nm) and their insolubility in the lung lining fluid. Some, not all, carbon nanotubes will be similarly insoluble and will be of a length which makes them difficult to remove if they are inhaled into the lung. However it has not yet been demonstrated that these fibres do pose the same risks as asbestos.
Q:
Do current regulations cover the use of nanoparticles?
A:
Current regulations do not specifically address nanoparticles. However in most cases they provide a framework by which the risks of nanoparticles can be assessed if the specific properties of nanoparticle forms are taken into account.
Q:
What workplace exposure limits (WELs) apply to nanoparticles?
A:
WELs apply to the chemical form of nanoparticles (for example carbon, for carbon nanotubes) but have not been specifically adjusted to take account of any differences in the toxicity of nanoparticle forms of these chemical. It is not clear whether changes of this type will be made in the near future.
Q:
What precautions do I need to take when using or making nanoparticles?
A:
Just like working with any other chemicals, a risk assessment should be the first step in ensuring that work activities are appropriately and effectively controlled. The precautions needed depend on that risk assessment.
A simple approach to risk assessment comprises these steps:
1. Identify the hazards
2. Decide who might be harmed and how
3. Evaluate the risks and decide on precaution
4. Record your findings and implement them
5. Review your assessment and update if necessary
One of the difficulties with nanoparticles is that this information may be incomplete. Where significant gaps in knowledge remain, your risk assessment and risk management decisions need to suitably cautious, providing higher levels of protection as the uncertainty about the risk increases. SAFENANO can help to fill in these information gaps with the latest knowledge about nanoparticle risk issues.