Nanotechnology Safety at SP

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Nanotechnology Safety at SP
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PURPOSE

• For the present, there is minimum regulatory
  control for nanoparticles (NP). This suggests
  that for the short-term industry must
  self-regulate itself (take the lead in evaluating
  and managing risks).
• Localized standards of care or safety
  approaches will need to be promulgated that
  protect health and environmental risks when
  working with nanoparticles (NP).
• This presentation gives draft SHE standards of
  care for working with NP at SP.

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KEEP IN MIND...

• Current understanding of the environmental and
  human health effects of NP is limited.
• Ultimately, information about definite health
  effects will emerge. Until then-it will be
  prudent to adopt conservative approaches for
  managing and controlling perceived NP risks.
• Unfortunately, the commercialization of
  nanomaterials is growing so fast that it is
  difficult to study NP impact on human and
  environmental health issues. i.e. Recent reports
  in Europe over Magic Nano spray

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DEFINITIONS

• Nanotechnology simplest definition is
  technological developments on the nanometer (nm)
  scale. Nano is a prefix meaning one billionth 1
  nm 10-9 m
• Nanoparticle (NP) any substance less than 100
  nm. (A single human red blood cell has a
  diameter about 5000 nm)
• Nanomaterial any material that contains a
  certain proportion, or is composed entirely of,
  nanoparticles. Could be nanotubes, nanowires,
  quantum dots.

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HOW BIG IS A NANOMETER?

• A nanometers is equal to one billionth of a meter
  or 10-9 m
• A flea is 10-3 m or 1 mm
• A human hair is 10-4 m or 80 um
• A red blood cell is 10-5 m or 7 um
• A strand of DNA is 10-8 m or 2 nm
• A bundle of nanotubes is 1.4 nm wide
• A carbon 60 fullerene is 0.7 nm

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THERE IS A CRUCIAL NEED TO STANDARDIZE
TERMINOLOGY AND DEFINITIONS, DEVELOP METHODS TO
MEASURE NP, AND IMPROVE CONTROL MEASURES THAT
LIMIT OCCUPATIONAL EXPOSURE!
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Silver nanowire 50 nm thick, 100 nm wide and 5 um
long. (Quantronics)
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Some Nanotechnology Applications

• Energy storage, production, and conversion
• Agricultural productivity enhancement
• Water treatment and remediation
• Disease diagnosis and screening (Bio- and Nano-)
• Drug delivery system
• Food processing and storage
• Air pollution and remediation
• Construction
• Health monitoring
• Vector/Pest control

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GENERAL BACKGROUND

• NP applications will definitely expand with time.
  
• NP enhances coating surface properties.
• NP can be purchased or manufactured either bound
  or unbound.
• Many small particles create a large amount of
  surface area, which tends to become electrically
  charged, leading to chemically reactive
  conditions.
• NP lt50 nm have properties that do not follow
  classical physics laws-do follow quantum physics
  laws.

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Particle Number and surface area for
area for 10 mg/m3 airborne particles Particle
Particles/ml Particle
Surface Diameter (um) of air
area (um2/ml of air) 2.0
2 30 0.5
153
120 0.02 2,390,000
3000
Large particle
Small particle
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GENERAL BACKGROUND

• Safety Concerns-Small size particles (ltlt0.1 um)
  may have higher human risks than the range from
  0.1 to 30 um. We know very little about most of
  them compared to the same substances with larger
  particle sizes.
• It is difficult to characterize worker exposure
  to particles that have a diameter less than the
  wavelength of light. Therefore SHE risk
  assessment technique may not directly apply!

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POTENTIAL EXPOSURE RISKS

• Airborne contamination of workplace
• Handling of product/material
• Cleaning/Maintenance activities
• Leakage/Spillage Accidents
• Product Drying

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KEY TOXICOLOGICAL FACTORS
Physical Related
Chemical Related

• Composition and Structure
• Solubility
• Reactivity
• Surface Chemistry
• Aggregation Potential

• Surface Area
• Shape
• Density
• Particle Size

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TOXICOLOGICAL ISSUES

• NP may be more toxic than larger particles on a
  mass basis (high surface area to mass ratio).
  The smaller the particles the more reactive and
  toxic they become. Deeper into lung.
• Not all materials will represent risks
• Potential for new toxicities from engineered
  nanomaterials?

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TOXICOLOGICAL ISSUES

• The major routes of entry of NP into the body
  are
• Lungs (Inhalation)-Considered to be a big
  concern.
• Gastrointestinal tract (Ingestion)
• Dermal (Absorption)-Little information about
  dermal exposure from NP. SPE data is not readily
  available. Large exposure site!

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TOXICITY STAGING

• Route of Exposure
• Dose
• Duration of Exposure
• Movement in Body
• Interaction within Body

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HUMAN HEALTH EFFECTS

• Examples of possible health issues that have been
  reported in animal studies are oxidative stress,
  inhalation/transdermal assimilation concerns,
  asthma, chronic pulmonary diseases, cancer,
  neurodegenerative diseases, alteration of heart
  electrical activity, translocation (i.e. crossing
  of blood-brain barrier), and cell signaling.
  Strong evidence that pulmonary inflammation is
  related to surface area.
• At present there are no national occupational
  exposure standards? In fact few human research
  studies have been performed to date

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POSSIBLE REGULATORY ACTIVITY

• OSHA HAZCOMM (MSDS)
• EPA RCRA, TSCA, Clean Water/Air
• FDA Cosmetic Act
• NIOSH Active in TiO2
• STATES

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NIOSH ACTIVITY

• Presently involved w/drafting exposure criteria
  for Titanium Dioxide
• Material is used widely
• Animal studies (rat) show pulmonary inflammation,
  trauma, tissue damage, and lung tumors. Appears
  to be particle size dependent.
• REL of 1.5 mg/m3 for particles 0.1 to 10 um
  (fine) and REL of 0.1 mg/m3 for particles lt 0.1
  um (ultrafine)
• NOTE Elevated lung cancer rates have been
  reported among workers exposed to welding fumes
  and diesel particulates.

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HUMAN HEALTH EFFECTS

• It is now postulated that human health effects
  are more closely related to total surface area of
  particle than their mass-needs verification!
• At small particle sizes-atoms and molecules bond
  differently than when in bulk substances.
• Models that address particle deposition in the
  lung exist.

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ICRP Lung Model
15 nm
3 nm
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RECENT BIO-EFFECTS OF NP

• Water soluble carbon nanotubes fed intravenously
  to mice were excreted intact in urine and were
  not retained in spleen, heart, and liver. This
  finding gives some evidence that nanotubes might
  be used for medical therapeutics purposes.
  Reported in Proc Natl Acad Sci-USA-2006)

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IF WORKING WITH UNBOUNDED NP

• Total enclosure of process with negative
  ventilation or partial enclosure with localized
  exhaust ventilation (LEV). Install indicators
  to show air flow/present of ventilation. Use
  dedicated exhaust system (May want double
  enclosure). Particle entrainment is safety
  feature.
• Treat NP as if they were a gas (high to low
  concentrations). Particles may undergo rapid
  mixing and dispersion. As NP collide
  coagulation/agglomeration occurs and NP can be
  collected in bulk form-and probably not undergo
  re-suspension.

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IF WORKING WITH UNBOUNDED NP

• Beware that small particles have low settling
  velocity and remain airborne longer (minimal
  inertia). Being airborne they can be trapped on
  wall, ceiling, floor surfaces, and people far
  removed from origination point.
• Cover skin. Double up on gloves. Consider
  wearing protective long-sleeved coats (i.e.
  layering approach). Protective coats will need
  to be cleaned on a regular basis.
• No eating/drinking in work area.

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IF WORKING WITH UNBOUNDED NP

• HEPA filters/scrubbers (also N100) can be useful
  for particles less than 100 nm (efficiency
  increases as particle size decreases). Not sure
  about their use at 2-10 nm. Need to be aware of
  facial seal leakage potential.
• Will be difficult to clean and maintain
  laboratory equipment (as well as walls/floors)
  containing nanoparticles without exposing workers
  (use of wet methods)
• It is not clear that existing knowledge about
  conventional chemicals can be applied predict
  risks of nanomaterials.

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IF WORKING WITH UNBOUNDED NP

• Limit the number of workers per room involved
  with NP. Reduce actual exposure time.
• Potential for dust explosions/fires composition,
  increased surface area, NP in air longer

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IF WORKING WITH UNBOUNDED NP

• Electrostatic air filters may be use to collect
  NP since charged particles have higher deposition
  efficiency than uncharged particles. Some work
  being done with soft x-rays and charged particles
  to further enhance collection
• NP may act synergistically with O2 and NOx
• Laser Generated Air Contaminants (LGAC) could be
  a source of NP.
• Some basic medical surveillance for lung
  capacity/skin issues may be necessary.

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IF WORKING WITH UNBOUNDED NP

• At present, MSDS does not reflect
  nanospecificity. Not sure if OSHA defines NP as
  falling under Hazard Communication.
• Bio-accumulation of particles can occur in
  plants, crops, water, and ground. Problems
  w/waste disposal (options encapsulation or
  incineration).
• May need to consider life-cycle testing on
  products. Avoid future liabilities
• In view of the above concepts perhaps it is best
  not to work with unbounded NP!

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CONTROL OF WORKPLACE EXPOSURES TO NP.
Engineering Controls
Training and Good Work Practices
Personal Protective Equipment
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Farewell and Thanks for Coming!323232