Last Thursday, 18 November 2010, I attended a seminar given by NIVA:
Nordic Tour 2010:
Health effects and risks of nanoparticles
This was a very interesting seminar. As perhaps expected, there were perhaps more questions raised than answered. But it was very interesting to learn about the different problems that arise when faced with a new technology, in this case, related to how to assess the health risk of nano-particles.
In general I think it is safe to say that people aren’t expecting this to be a great problem. However, some of these nano-particles do have very negative health effects. The biggest problem seems to be that the science and industry are moving very fast, but regulations and health effects are lagging way behind. Although, fortunately, many companies do not want to spend time and money to market something that could be a health risk later
It seemed that even the definition of nano-material isn’t clear yet, although defining a nano-material as having one dimension smaller than 100 nm (nano-meters, 10-9 m), seems to be the most likely outcome. However, many view particles smaller than about 1000 nm as nano.
A few examples of interesting points:
- Gold, which in bulk is very inert and has a melting point at 1200°C, changes its caracter drastically as a nano-material. Then it is very inert and has a melting point of 200°C !
This clearly shows that we need to rethink, and measure, the properties of all material when used as nano-particles!
Perhaps not been fully realized, nano-particles used in some products, probably without any assessment of health effects. - Experiments on rodents (Harri Alenius) exposing them to nano-particles showed that TiO2 coated with silica caused inflamation, although either material alone had no effects !
- But, rodents that had pre-existing allergic astma got better when exposed to these particles (TiO2 coated with Si)!
- It is very difficult to measure the concentration of these particles, for instance in a workplace. Requires careful measurements of background, and material ejected. Then it is possible to show that the size distribution changes. The concentration of small particles is though often measured low, since many of those small particles attach themselves to larger particles (Keld Alstrup Jensen).
- Different methods to estimate the dispersivity of nano-particles added to bulk can give different results. This was demonstrated with an example for rubber reinforced with nano-particles (Gissur Örlygsson).
- When developing medicine, the producers have to demonstrate that none of the material, both in combination, and independently, have no harmful effects and are not left in the body. This can be very difficult to show, and may lead to many effective nano-techniques not reaching the stage of practical use (Már Másson).
- Never the less, it is possible to buy nano-particles in bulk (Kristján Leósson). The benifits are not really known, but some of the side effects are – see video below.
- Socks that have nano-silver particles, so they won’t smell, loose all the nano-particles after 10 washes (but who needs to wash socks that don’t smell). This will enter the environment, and nobody really knows what happens to it there !
Many other interesting things were mentioned.
The homepage of Niva is http://www.niva.org/
Nano-particles are sold, it seems, without any studies of health risks, or environmental effects. See for instance, http://www.utopiasilver.com/. Don’t be tempted though ! The only real effects are seen in the video below, Blue man – drank nano-silver.
Hope I haven’t said anything wrong above, but any corrections or information about the environmental effects are welcomed.
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