nano-materials are also likely to be another asbesto to human health

A word from Leechard:

A friend send the following link to us which is important and need to have a look at. The essay from Guardian may be a bid long, but people interested should not miss it.

Nano technology, could be harmful like Asbseto(石棉)?

If we can do nothing now, at least, we should know some more about it.


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Nano-materials are also likely to be another asbesto to human health.

At present, there are no evidence to prove that Nano-materials, like Asbestos in the past, could have harmful effect to human.

but, No evidence simply means we dont know.

There is no safety test, no regulations, on the negative use of nano-materials when they are employed in large scale.


And the point is:

Nano technology, like the atomic bomb, once brought into life, could never be
get rid of.......




http://www.independent.co.uk/news/science/the-big-question-what-is-nanotechnology-and-do-we-put-the-world-at-risk-by-adopting-it-1015518.html.



What is nanotechnology?
The Royal Commission on Environmental Pollution has just published a report on novel materials

Nanotechnology derives its name from the nanometre, which is a billionth of a metre.
(a human hair is about 80,000 nanometres wide.)

The Royal Commission found no evidence of harm to health or the environment from nanomaterials, but this "absence of evidence" is not being taken as "evidence of absence". In other words, just because there are no apparent problems, this is not to say that here is no risk now or in the future.

What is covered by the term nanotechnology?

There are about 600 consumer products already on the market that use nanotechnology. They include nanoparticles of titanium dioxide added to sun creams to make them transparent instead of white, or tiny fragments of silver that are added to sports equipment to make them odour-free – the silver acts as a powerful anti-bacterial agent. Nanomedicine are also being developed to fight cancer and other fatal diseases.

Many companies are taking up the opportunity of using them in products with little or no knowledge of how they may have an impact human health or the environment. The silver particles in sports clothing might end up killing off bacteria in sewage systems for example.

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A molecule of DNA is an example of a natural nano-scale substance with the diameter of its double helix structure measuring about one nanometre. A typical virus, meanwhile, is about 100 nanometres wide.


"It is not the particle size or mode of production of a material that should concern us, but its functionality."

Take gold, for instance, which is a famously inert substance, and valuable because of it. It doesn't rust or corrode because it doesn't interact with water or oxygen, for instance. However, a particle of gold that is between 2 and 5 nanometres in diameter becomes highly reactive. This is not due to a change in chemical composition, but because of a change in the physical size of the gold particles.


How can this result in a change of function?

One reason is to do with surface area.

Nanoparticles have a much bigger surface area-to-volume ratio than microparticles a thousand times bigger. It is like trying to compare the surface area of a basketball with the combined surface area of pea-sized balls with the same total weight of the single basketball.
The pea-sized balls have a surface area many hundreds, indeed thousands of times bigger than the basketball, and this allows them to interact more easily with the environment. It is this increased interactivity that can change their functionality – and so make them potentially more dangerous to health or the environment.

"As many chemical reactions occur at surfaces, this means that nanomaterials may be relatively much more reactive than a similar mass of conventional materials in bulk form," the Royal Commission said.

Are there precedents?
The Commission cites several examples of health problems caused by the introduction of novel materials. Asbestos, for instance, was an infamous example of a material that provided tremendous benefits as a fire retardant, but when asbestos fibres were inhaled, it resulted in highly malignant cancer mesothelioma.

Where did the idea of these dangers emerge?

The first scientist to see the potential of nanotechnology was the American physicist Richard Feynman who gave a famous 1959 lecture to the American Physical Society entitled "there is plenty of room at the bottom".
Although it was Feynman who first talked about the potential advantages of technology on the small scale, it was an American engineer and author called Eric Drexler who coined the term "nanotechnology" in his 1986 book Engines of Creation.

It was also Drexler who first warned of the risk. He described a future in which tiny, self-replicating robots would take over the world – a view he has since disowned.

http://www.independent.co.uk/news/science/the-big-question-what-is-nanotechnology-and-do-we-put-the-world-at-risk-by-adopting-it-1015518.html