Overview: Health, Safety, and Environmental Issues for Nanotechnology

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Overview Health, Safety, and Environmental
Issues for Nanotechnology
James Yardley May 7, 2004
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Nanotechnology Health, Safety, and Environment.
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Occurance of nanoscale particulate materials.
From presentation E. Clayton Teague, NNCO, April
2004.
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Potential bio-uptake of nanoscale particulates.

• Nanoparticles may enter living cells via
• Endocytosis
• Receptor activation for initiation
• Membrane penetration
• Generally occurs with very hydrophobic particles
• Transmembrane channels
• May be seen with very small nanoparticles (lt 5
  nm?)

Adapted from presentation of Vicki Colvin, Rice
University.
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Potential bio-accumulation of nanoscale particles.

• Accumulation of a substance within a species can
  occur due to lack of degradation or excretion.
• Many nanoparticles are not biodegradable.
• If nanoparticles enter organisms low in the food
  web, they may be expected to accumulate in
  organisms higher in the food web.

Very little is understood about possible
health effects of nanoparticle exposure!
Adapted from presentation of Vicki Colvin, Rice
University.
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Potential human hazards for nanoscale
particulates.
Inhalation Inhaled particles induce
inflammation in respiratory tract, causing tissue
damage. Example Inhalation of silica particles
in industrial workers causes silicosis.
Dermal exposure Particles may enter body
through the skin. Potential hazards are unknown
at present.
Ingestion nanoparticles may cause liver damage.
Ingested nanoparticles (i.e. for oral drug
delivery) have been found to accumulate in the
liver. Excessive immune/inflammatory responses
cause permanent liver damage.
Other ocular, .
Adapted from presentation of Vicki Colvin, Rice
University.
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Semiconductor nanoparticules.
Red- and green-emitting quantum dots highlight
the mitochondria and nuclei, respectively, of
human epithelial cells in culture. Although these
colorful nanocrystals don't seem to harm the
cells, could they pose unforeseen hazards to
people or the environment?
Silica-coated semiconductor nanocrystals are
readily incorporated into a wide variety of
eukaryotic cells. In experiments where the
quantum dots are deposited on a collagen
substrate and then cells are deposited on top of
this, the cells incorporate any quantum dots that
underlie them When the cells migrate on a
substrate, they ingest all the dots they pass
over providing a convenient and rapid way for
assessing the cells' potential to metastasize, or
spread (as a cancer) from one part of the body to
another Adv. Mater., 14, 882 (2002). The dots
appear to go into cells as "inert spectators."
The cells remain healthy and even continue to
divide, with each cell division reducing the
number of dots in any given cell. The dots have
no discernible effect on the cells. ---- A. Paul
Alivisatos
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Wahrheit (Dupont), January 2004.
Optical micrograph of lung tissue from a rat
exposed to single-wall carbon nanotubes (1 mg/kg)
1 week post exposure. Note the early development
of lesions surrounding the instilled SWCNT
(arrows) and the nonuniform, diffuse pattern of
single-wall carbon nanotube particulate
deposition in the lung (X 100).
Low-magnification micrograph of lung tissue from
a rat exposed to single-wall carbon nanotubes (1
mg/kg) at 1 month postinstillation. Note the
diffuse pattern of granulomatous lesions
(arrows). It was interesting to note that few
lesions existed in some lobes while other lobes
contain several granulomatous lesionsand this
was likely due to the nonuniform deposition
pattern following carbon nanotube instillation.
Magnification X 20.
Higher magnification optical micrograph of lung
tissue from a rat exposed to single-wall carbon
nanotubes (1 mg/kg) at 1 month postinstillation
exposure. Note the discrete, multifocal
mononuclear granuloma centered around the carbon
nanotube material (arrows). Magnification X 400.
D. B. Wahrheit et. al. Toxilogical Sciences 77,
117-125 (2004)
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Presentation, ACS, January, 2004
From Lam presentation
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From Lam presentation
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From Lam presentation
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From Lam presentation
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From Lam presentation
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Concerns about granulomas and fibers.
Granulomas (miscropic nodules), consisting
particles, live and dead cells, and debris and
could impair cellular and physiological (gas
exchange) lung functions and give rise to
fibrosis, more defined nodules, and other
lesions. Fibers are generally of more health
hazard than other forms of particulates. It is
well established that the pathogenicity of a
fiber in the lungs directly correlates with its
biopersistency(Oberdorster 2000). NTs are
totally insoluble and probably one of the most
biologically nondegradable man-made
materials.Determining how the NT-induced
granulomas progress would require a
longer-duration study with this biopersistent
material.
From Lam presentation
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Observations and tentative conclusions.
Granulomas were observed in lungs 7 d or 90 d
after an instillation of 0.5 mg NT per mouse
(also in some with 0.1 mg) NT, regardless
synthetic methods, types and amounts of residual
catalytic metals, produced granulomas Lung
lesions in the 90-d NT groups, in most cases,
more pronounced than those in the 7-d groups.
Our study shows that, on an equal-weight basis,
if carbon nanotubes reach the lungs, they are
much more toxic than carbon black and can be more
toxic than quartz, which is considered a serious
occupational health hazard in chronic inhalation
exposures. If fine NT dusts are present in a
work environment, exposure protection strategies
should be implemented to minimize human exposures.
From Lam presentation
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Governmental regulation - particulate matter.
From presentation E. Clayton Teague, NNCO, April
2004.
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Problem areas for regulation of particulates.
From presentation E. Clayton Teague, NNCO, April
2004.
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NSF Guidelines for Nanocenter Research.

• Strong chemical and materials hygiene.
• HSE educational program for all participants.
• Protection against inhalation and dermal
  exposure.
• Proper procedures for handling of potentially
  hazardous materials.
• Strict adherence to government and institutional
  regulations.
• Proper disposal of waste materials.
• Dissemination of information regarding potential
  hazards.
• Proper reporting of all reportable incidents.