Occupational Safety and Health Issues and Nanotechnology

1
Occupational Safety and Health Issues and
Nanotechnology

• Paul A. Schulte, Ph.D.
• Centers for Disease Control and Prevention
• National Institute for Occupational Safety and
  Health

The findings and conclusions in this report are
those of the author and do not necessarily
represent the views of the National Institute for
Occupational Safety and Health.
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NNI Agencies Strategy For Nano-EHS Research

• Support research to safely develop and apply
  nanotechnology for societal benefit and economic
  growth in parallel with research to better
  protect public health and the environment.
• Integrate the results of both components
• Aim to maximize benefits at the same time as
  developing an understanding of potential risks
  and means to manage such risks
• EHS Research informed and influenced by the
  broader NNI research portfolio
• EHS Research also informed by research and
  information needs of agencies with regulatory and
  oversight responsibilities
• Collaborate with international colleagues in ISO
  and OECD share data, agree on terminology,
  testing protocols,

Released Feb. 14, 2008
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Role of Nano-Related EHS Researchin Risk
Management of Nanomaterials
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Consensus Agency Roles and Responsibilities
? Coordinating Agency Leadership role in
coordinating and communicating with other NNI
agencies ? ContributorHave funded or are
planning to fund or conduct research in category
? UserHave expressed a need for, or
expectation to make use of, research outputs or
information to support missions responsibilities
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What could a Nanoparticle be?
Dr. Andrew Maynard Woodrow Wilson International
Center for Scholars
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Transport
Academic
Research Laboratories
Commercial
Warehousing/Maintenance Waste Handling
Start Up/Scale Up Operations
Transport Warehousing/Maintenance
Manufacturing/Production
Warehousing/Maintenance Transport Waste Handling
Incorporation in Products
Maintenance of Products Manipulation of
Products Application of Products - Medical
Delivery
Disposal / End of Life
Recycling
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Critical Occupational Safety and Health Issues of
Nanotechnology in the Workplace
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Can an algorithm be developed to classify
engineered nanoparticles by degree of hazard?
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Effects of Various Engineered Nanoparticles
Schulte et al, 2008
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Effects of Various Engineered Nanoparticles
Schulte et al, 2008
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Parameters That Could Affect Nanoparticle Toxicity

• Size
• Shape
• Composition
• Solubility
• Crystalline structure
• Charge
• Surface characteristic
• Attached functional groups
• Agglomeration
• Impurities

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Views Toward Engineered Nanoparticles
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Hazard Categories in BSI (PD - 6699-2)
British Standards Institute
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What metrics and measurement techniques should be
used in exposure assessment?
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Size and Surface Area

• Chemical, physical, and biological interactions
  take place on the surface of a particle.
• Nanoparticles offer more of all of these. They
  also present new challenges in detecting and
  measuring these interactions.

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Lung tumor response is associated with particle
surface area dose of fine or ultrafine PSLT
Poorly soluble low toxicity particles
Kuempel, 2006
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Multiple Tools Needed to Assess Exposure

• Mass Links to historical data, lacks sensitivity
  and specificity
• Size distribution More information , not always
  easy, not specific
• Number concentration Fairly simple with
  monitors, not specific to particles, question of
  relevance for health effects
• Surface area Some relevance based on toxicology
  and technology is available
• Each one may be right

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Instrumentation Issues

• Integrated filter-pump method
• Limitation Cannot collect sufficient mass in the
  nanoscale size range
• Direct Reading
• Limited in the ability to detect
• Small particles
• Discriminate large from small
• Identify a specific type of particle
• Both have limitations in terms of practicality

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What exposures are occurring in workplaces?
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Examples of NIOSH Field Investigations
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Need for a comprehensive job-exposure matrix
(JEM) for each worker
Where Time (Ji,Pj) is the workers time on job i
during exposure period j.
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What are the limits of engineering controls and
PPE with respect to engineered nanoparticles?
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Conventional Controls Should Work
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Filtration performance of an example
NIOSHapproved N95 filtering facepiece respirator
n 5 error bars represent standard
deviations TSI 3160 Flow rate 85 L/min
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What occupational health surveillance should be
recommended for workers potentially exposed to
engineered nanoparticles?
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Surveillance and Research Approaches for
Nanoparticle Workers
Document the presence of engineered nanoparticles
Identify and record individual nanoparticle
workers
General medical testing
Targeted medical testing
No action
Consideration for exposure registeries
Exposure assessment
Group analysis for trends
Biological monitoring
Multi-facility epidemiologic research
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Should exposure registries be established for
various groups of workers potentially exposed to
engineered nanoparticles?
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Exposure Registries

• Definition
• An enrollment of persons exposed or likely to
  have been exposed to occupational or
  environmental hazards

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Exposure Registries

• Purpose
• Delineate a population at risk
• Follow a cohort to ascertain exposure disease
  associations
• Follow a cohort to ensure appropriate primary and
  secondary preventions and medical surveillance
• Follow a cohort for appropriate social, legal,
  and economic support
• Demonstrate societal concern for a cohort
• Notify a cohort of important information not
  available when registry was initiated.

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Examples of Exposure Registries

• Beryllium
• Pregnancy exposure registries antiviral
  prophylaxis
• Dioxin
• Benzene
• Trichloroethylene
• Trichloroethane
• World Trade Center Health Registry
• Lead
• 2-Naphthylamine

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Should engineered nanoparticles be treated as
new substances?
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Engineered Nanoparticles vs. Larger Particles of
the Same Compositions

• Generally more reactive
• Generally more toxic
• Current OELs may not be adequate

33
Pulmonary Toxicity Studies- Carbon Nanotubes

• Aspiration of SWCNT resulted in
• Rapid but transient inflammation and damage
• Granulomas and fibrosis at deposition sites of
  large agglomerates of SWCNT
• Rapid and progressive interstitial fibrosis at
  deposition sites of dispersed SWCNT

• Message
• SWCNTs more fibrogenic than an equal mass of
  ultrafine carbon black or fine quartz.
• Doses approximated exposure at the PEL for
  graphite (5 mg/m3) for 20 days
• Message The PEL for the large form of a
  material may not be a good guide for the nano
  form.

Graphics courtesy of Andrew Maynard and Anna
Shvedova
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Risk Assessment Ultrafine (Nano) TiO2

• NIOSH draft recommended exposure limits (RELs)
• 1.5 mg/m3 fine TiO2
• 0.1 mg/m3 ultrafine TiO2
• Reflects greater inflammation tumor risk of
  ultrafine on mass basis
• www.cdc.gov/niosh/review/peer/tio2/
• Same message The OEL for a material in its
  large form may not be appropriate for the Nano
  form

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Adjusting Current REL In Concept
OELFP
(SSANP/SSAFP) x (DFNP/DFFP)(ActivNP/ActivFP) x
(UF)
OELNP

• Where
• OELNP is the new occupational exposure limit for
  the nanoparticle and OELFP is the existing OEL
  for the fine particle.
• SSANP and SSAFP are the specific surface areas
  (m2/g) of the nanoparticle and the fine particle
  material, respectively.
• DFNP and DFFP are the respective deposition
  fractions of the nanoparticle or fine particle in
  the respiratory tract or region of the
  respiratory tract associated with the adverse
  response.
• ActivNP/ActivFP is a measure of the surface
  reactivity (e.g., free radical activity) of the
  nanoparticle relative to the fine particles.
• UF is a currently undefined factor that relates
  to the degree of certainty with regard to the
  health protectiveness of the existing OEL.

Kuempel et al, 2007
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Critical OSH Issues on Nanotechnology in the
Workplace

• Can an algorithm be developed to classify
  engineered nanoparticles by degree of hazard?
• What metrics and measurement techniques should be
  used in exposure assessment?
• What exposures are occurring in workplaces?
• What are the limits of engineering controls and
  PPE with respect to engineered nanoparticles?
• What occupational health surveillance should be
  recommended for workers potentially exposed to
  engineered nanoparticles?
• Should exposure registries be established for
  various groups of workers potentially exposed to
  engineered nanoparticles?
• Should engineered nanoparticles be treated as
  new substances?

Schulte et al, 2008