02.04.2007

Potentially Big Hazards In Microscopic Packages

In an age where computer hard drives have shrunk from filling a room to
dangling off a keychain, it's no surprise that other aspects of manufacturing
have made a natural progression to the miniature. At the extreme level of
smallness is "nanotechnology," a rapidly growing phenomenon where everything
happens at the level of the nanometre (nm) - a billionth of a metre (10-9 m).

Nanotechnology is the manipulation of matter on a near-atomic size scale, to
produce new structures, materials and devices. It is used in medicine,
biotechnology, energy, the environment, and in computing and
telecommunications. At this atomic level, materials have different, unique
properties that affect their physical, chemical and biological behaviour.

The world has seen many examples of this rapidly-growing technology in recent
years. It is used to create consumer products such as dental adhesive, tennis
balls, immuno-suppressant drugs, and refrigerators. Manufacturers of outdoor
wear use nanoscale technologies to create fabrics that wick sweat away from the
wearer's skin, keeping it dry, and cool enough to prevent excessive sweating. A
team of researchers in the US recently discovered a way to quickly,
inexpensively look at a single strand of DNA by positioning the molecule in
nanoscale slits.

But What About The Risks?

Nanotechnology is fairly new and in the early stages of development. The
scientific knowledge of its effects on human health is limited and there is
uncertainty about the risks involved for workers in this new industry.

The National Institute for Occupational Safety and Health (NIOSH) in the US is
currently researching nanoparticles to find out how workers might be exposed to
them in the manufacturing or industrial use of nanomaterials, and how
nanoparticles affect or interact with the body's systems.

NIOSH has developed a document called Approaches to Safe Nanotechnology: An
Information Exchange with NIOSH to raise awareness of potential safety and
health concerns from exposure to nanomaterials.

The European Commission and the United Nations Environment Programme (UNEP) are
other important research bodies committed to R&D into the potential impact of
nanotechnology on human health and the environment.

In Canada, the Institut de recherche Robert-Sauvé en santé et en sécurité du
travail (IRSST) recently released a report outlining what's known about the
health effects of nanotechnology so far, and listing preventive measures.

According to the IRRST, nanometric particles are clearly more toxic than larger
particles of the same substance. For this reason, researchers are treating
nanoparticles of a particular substance as a new product with its own toxicity.

In Quebec alone, there are about 200 professor-scholars active in the field and
over 1,000 students that may have already been exposed to nanoparticles. People
absorb nanoparticles primarily via the respiratory route, just as they would
absorb other dusts.

The IRSST report says one alarming characteristic of nanoparticles is their
ability to pass from the pulmonary epithelium and eventually to the
bloodstream, which distributes them throughout the body and sometimes even to
the brain. Certain nanoparticles modify blood parameters and accumulate in
particular organs, including the liver and spleen.

Besides being a respiratory hazard, many types of nanoparticles have
significant reactivity potential that can result in fires or explosions.

Prevention

With limited knowledge about the hazards of nanoparticles, the facts about
disease prevention are also questionable at this early stage. Using respiratory
protection to control exposure through breathing, for example, remains to be
proven as an effective solution, though high-efficiency chemical cartridges are
a good precaution. Even controlling exposure through ventilation can be
difficult, says the IRRST, since nanoparticles "tend to behave like gases
rather than solids."

Until research progresses further, the IRSST recommends strict preventive
measures to limit emissions of nanoparticles, both within and outside of the
work environment. Many countries have begun to enact laws that protect workers
from potential exposure, in hopes of preventing an increase in occupational
disease.

More info


AplusA-online.de - Source: National Institute of Occuaptional Safety and Health