02/13/2017

How to perform nanomaterial exposure assessment in the workplace

Do you think you might have exposure to nanomaterials in your workplace?
Engineered nanoparticles are unique. They are generally smaller than both red
blood cells and viruses, don't weigh much, and have a great amount of surface
area proportionate to their size. These particles are increasingly used in a
wide variety of products, ranging from cosmetics to concrete. Workers who make
and use engineered nanoparticles would be the first potentially exposed to any
new material. So, it seems important to be able to determine whether workers
are exposed to these materials in an occupational setting, right?

Because of the unique properties of these materials, it can be a challenge to
identify whether there is a potential for worker inhalation exposure. Why?
Well, first because they are so small it is difficult to see nanoparticles
unless we use electron microscopy, which is time consuming and expensive.
Second, even if we collect a sample and weigh it, there may not be enough mass
to be detected. Traditional industrial materials, composed of particles that
are larger in size, do not pose such hurdles for sampling and analyzing. So
with these challenges, how do we identify if nanomaterials present the
potential for occupational inhalation exposure in a workplace?

The National Institute for Occupational Safety and Health (NIOSH) has been
researching this very question for over a decade. In 2009, based on both
laboratory research and field investigations, NIOSH developed and was the first
to recommend using the nanoparticle emission assessment technique (NEAT). This
technique made use of a condensation particle counter that could be used to
identify tasks that result or can result in the emission of nanoparticles into
the surrounding air. Then, task-based filter samples were used to confirm the
presence of these materials, using both laboratory elemental analysis and
electron microscopy. This initial approach didn't effectively address the
potential for background contamination from incidental nano-sized particles
(unrelated to emissions from the work process being studied) or exposure over a
full workday. In addition, it was heavily dependent on the use of direct
reading instruments (DRIs), which are nonspecific aerosol monitors and subject
to interferences such as background incidental particles. So, based on the need to surmount these
limitations, and a desire to learn more about potential occupational exposures,
NEAT was updated.


Further Information


AplusA-online.de - Source: The National Institute for Occupational Safety and Health (NIOSH)