Comments
Page 5. Section 3a, last paragraph.
The sentence on possibly including the effects of dimensionality on health and
safety issues is intriguing.I would suggest that a good definition of nanotechnology,
nanomaterialsand nanodevices should be independent from the possible health
andenvironmental impacts, thus focusing the definition on the technologyitself.
It is then much easier to explore potential health and environmental impact
based on material and device properties within the generally accepted definition.
There seem to be a number of loose definitions for nanotechnology floating around,
but one that I'm finding useful at the moment from a health standpoint is 'technology
that deals with engineered nanometer-length scale devices, structures and surface
layers' This is broad enough to encompass (from the inhalation exposure standpoint)
individual nanometer particles, collections (agglomerates) of nanometer particles,
and nano-devices (such as biomechanical constructs) that may inadvertently enter
the body.
Page 6 Section 3c, para 1.
Straying from my original aim to comment on health aspects, I assume something
is missing here, but I was interested in the statement that '... Applications
for the young would be most important, ...'!
Page 6 Section 3c, para 5.
Straying again, the concern that there is no strategic view on the development
of nanotechnology in the UK is a recurring theme in the report. This is a vitally
important point, and should be emphasized very strongly indeed. It is becoming
very clear that this level of technology requires a high tech approach to evaluating
health risks, including the development of new and novel risk models, and the
development/adoption of cutting edge research tools and techniques. The only
way that a relevant health and environmental impact framework can be formulated
for nanotechnology is by the coordinated, parallel development of health and
environmental impact-based research programs. This in turn will only be achieved
within the context of a strategic view on the development of nanotechnology.
Bottom line - you will not be able to address health and environmental impact
of such a rapidly developing technology without strategic planning and coordination
at the national (and international) level.
Page 7 Section 3e, first para.
Nanomaterials may be the most obvious area where health and safety issues will
manifest themselves. However, consider that nanotechnology aims to exploit the
unique properties of nanometer-scale devices and structures, forming products
that are better at achieving specific ends than those previously available,
or enabling previously unattainable goals to be attained. The questions need
to be asked of these materials and devices: What will their impact be when introduced
to systems outside the original design parameters, and what will be the impact
of initially unforeseen activity/behaviour? Both questions are pertinent to
health and safety issues, and are not restricted to nanomaterials alone.
Page 7 Section 3e, first para.
PM10 particles are NOT similar to nanoparticles, although nanoparticles make
up a subset of PM10. Comparing the largest particles in the PM10 aerosol fraction
– 10 micrometers - with nanometer-diameter particles up to 5 orders of
magnitude smaller is clearly inappropriate. We still know very little indeed
about the toxicity of particles in the PM10 range. Nanoparticles associated
with nanotechnology will have unique physicochemical attributes previously unencountered
by humans, and can not be simply lumped together with particles we feel we know
something about. Carbon nanotubes are receiving increasing attention in toxicity
and exposure studies. Given the material's physicochemical attributes, it can
be speculated that the material will be highly toxic if sufficient exposure
levels are reached, although our research has indicated that inhalation exposures
at least remain low when handling the material. I am not aware that sufficient
regulations exist to control the release of hazardous materials where the hazard
is unknown. Airborne nanotubes is a good, and topical, example: To my knowledge,
no-one has verified that emission control technologies can totally eliminate
the release of airborne nanotubes - either during production, processing, or
during the use of nanotube-containing materials and devices. Thus we have to
assume that some level of particles are entering the workplace/environment,
and people are being exposed to them. Does this constitute a health or environmental
hazard? Who can tell without relevant toxicology models and data. There will
be more complex materials being developed and used than carbon nanotubes in
the future, that will present even greater challenges.
Page 11 Section 4d i)
This is a good start, but gives very brief coverage to dealing with hazards
in order to facilitate the use of nanomaterials in products. Reducing exposure
of the workforce to hazardous materials to acceptable levels will be essential
- particularly in the light of current public concerns. However determining
acceptable levels requires an in-depth understanding of the potential toxicity
of the materials produced and the potential exposure routes. Without this knowledge,
it is difficult to design commercially viable control systems. Sure, you can
use clean-room or bio-safety containment conditions, but the cost will cripple
industry if this level of containment is unnecessary. In the absence of clear
guidelines and regulations, the most appropriate approach will be to use common
sense control systems to reduce exposure levels as far as is practicable, pending
further information on associated health risks.
Page 12 Section 4d vi)
The point that people have been exposed to nanoparticles since the dawn of time
[my words] is a good one, and should be emphasized. The analogy with asbestos
is good, although remember that it took much too long for the workforce and
general population to be protected adequately, leading to a lot of unnecessary
deaths. The statement that the toxicity of nanoparticles will depend on particle
size, concentration and surface area is not accurate, and should be modified.
For insoluble particles, we know that particle size, shape and surface area
are important. However surface activity must also play a key role. Therefore
it essential to know the surface chemistry and biology of the particles. You
can not afford to underplay the importance of surface and bulk physicochemical
properties in nanoparticles - these are what drive the desired unique properties
of engineered nanoparticles, and by inference what will also drive the undesired
properties!
Page 16 Section 5d
Regulator issues - regulations impacting on exposure and emission monitoring
and control in fabrication and processing industries may also play a role here.
Page 18 Section 6.
I can't see any coverage of health and environmental impact in this section.
However surely the fusing of mechanical and biological technologies will lead
to materials and devices with unique properties that will have the potential
to interact with biological environments in unpredictable ways. This is one
of the areas where I think nanotechnology has the potential to lead to a major
technological jump, and also the area where the health and environmental impact
is most unpredictable (in my opinion). Possibly more than in any other area
of nanotechnology, the questions need to be asked: What will the impact of materials
and devices be when introduced to systems outside the original design parameters,
and what will be the impact of initially unforeseen activity/behaviour?
Page 22 Section 7b para 3.
The point that the potential impact of nanotubes is reduced when held in a matrix
is well made. However, attention must be placed on their release from materials
during use and secondary processing (compare to the release of asbestos fibers
during asbestos abatement).
Page 23 1st para.
A number of studies into nanotube toxicity are at various stages of planning
or completion in the US.
General notes on section 7 of report
This section of the report is somewhat short, and focused on the physical aspects
of nanoparticles. I think though that as nanotechnology continues to develop
at an increasing pace, we need to avoid getting caught up in a narrow view of
what may or may not be important from health impact standpoint. The development
and use of unique materials and devices will present unique challenges to minimizing
adverse health impacts. The only way that we can begin to approach the challenge
is to develop a coordinated framework within which emerging health and environmental
concerns can be addressed, and to build in health and environmental risk components
to research and development programs. This will require national and international
coordination.
As a final comment, emerging nanotechnologies have the potential to impact on society in a positive way, and it would be unfortunate if the positive impact was diluted or thwarted through ignorance arising from insufficient attention being paid to quantifying the true nature of adverse health and environmental impacts.
Hope these are of some use. Looking forward to seeing the final report.
Dr Andrew Maynard
Senior Service Fellow
National Institute for Occupational Safety and Health
Robert A Taft Laboratory