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Nanotechnology and its Impact on the SH&E Profession

Nanotechnology and its Impact on the SH&E Profession

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Nanotechnology and its Impact on the SH&E Profession

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  1. Nanotechnology and its Impact on the SH&E Profession Presented by Robert C. Adams, MS, CIH, CSP ENVIRON International Corporation Princeton NJ

  2. Overview • Nanotechnology – a primer • Applications for nanomaterials • Types of engineered nanomaterials • Managing Uncertainty – The concern for nanoparticles • Toxicological studies • Health issues • Safety issues • Environmental issues • Engineering, PPE and administrative controls • Current thinking on ‘traditional’ control methods • Moving forward with SH&E management – what to do now

  3. Nanotechnology • Terminology • Nano - A prefix meaning one billionth (1/1,000,000,000) • Nanotechnology • Research and development of materials at the atomic, molecular or macromolecular levels, • Approximately 1 - 100 nanometer range. • Embraces a wide range of applications and products • Little agreement on the terminology • Nanomaterial – any material that contains a certain proportion, or is composed entirely of, nanoparticles

  4. Nanotechnology • Terminology (con’t) • Nanoparticle - nanometer-scale particles that are initially produced as aerosols or colloidal suspensions • Nanotubes • single-wall carbon nanotube • multi-wall carbon nanotubes

  5. Nanotechnology • Terminology (con’t) • Nanowires • Small conducting or semi-conducting nanoparticles with a single crystal structure and a typical diameter of a few 10s of nanometers and a large aspect ratio. • Quantum Dots • Nanoparticles made up of hundreds to thousands of atoms that behave like a single gigantic atom.

  6. Source: Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy

  7. Materials used as light-emitting diodes with the color determined by the size of the quantum dots Source: Phillips Carbon Nanotubes Source: BBC News July 29, 2004

  8. Model of a C-60 Buckminster Fullerene (Buckyball) Silver nanowire 50nm thick, 100nm wide and 5µm long Source: Quantronics

  9. Nanotechnology • Purposely engineered materials and devices that demonstrate new, unique and non-scalable properties and behavior due to their size and configuration • Will use “nanoparticle” in all further discussions

  10. Why Nanoparticles? • Nanoparticles < 50 nm have properties that do not follow classical laws of physics • Follow quantum physics • Can assume different physical, optical, electrical or magnetic properties • Nanoparticles have greater ratio of surface area to mass • Greater reactivity with other substances

  11. Applications for Nanoparticles • Nanotechnology is in the “pre-competitive” stage but… • Nanoparticles are here now! • Bumpers on cars • Paints and coatings • Stain-free clothing and mattresses • Burn and wound dressings • Ink • Protective and glare-reducing coatings for eyeglasses and windshields • Metal-cutting tools • Sunscreens and cosmetics • Longer-lasting tennis balls and light-weight, stronger tennis racquets

  12. Managing Uncertainty • What do we know about these nanoparticles? • What don’t we know? • Does the nature of nanoparticles present new safety and health risks? • What are the potential risks and what is the magnitude? • We know very little about health effects (though many are laying the foundation)

  13. Managing Uncertainty • What are (or could be) the • Occupational health effects; • Safety hazards; and • Environmental impacts?

  14. Managing Uncertainty • What can be expected concerning regulating nanotechnology risks? • There are no laws in the US currently regulating nanotechnology • What additional pressures will drive SH&E efforts • Insurance • Investors • Litigation • Moral and ethical obligations to the workforce and community

  15. Managing Uncertainty • What prudent steps are needed to manage the uncertainty? • Currently, SH&E programs are in the early stages of development • Now is the time to define needs

  16. Bottom Line Can we achieve the promises of nanotechnology while minimizing potential risks? Managing Uncertainty

  17. Workplace Issues • Current workforce mixed • R&D operations • Technology-based • Large numbers of small facilities and labs • Universities and small enterprises

  18. Workplace Issues

  19. Workplace Issues • Explosive growth projected in commercialization of nanotechnology • Hundreds of thousands of new and redefined jobs • Increasing shift toward piloting and ramping-up production operations • Full-scale production is projected to take years

  20. Workplace Issues • Employees in all areas will have potential for exposure • Workforce is on the front line • Appropriate controls available? • Methods to measure exposure?

  21. Toxicological Issues • Properties of nanoparticles that will influence toxicity • Particle size • Key factor in where particles deposit in the lung • May influence ability of nanoparticles to translocation to other organs • Composition/Structure • Presence of heavy metals (nickel, beryllium, aluminum, etc.) • Carbon nanotubes may exert different effects than carbon nanoparticles

  22. Toxicological Issues • Properties of nanoparticles that will influence toxicity (con’t) • Solubility • Soluble particles can dissolve in moist tissues • Insoluble particles may be cleared from the lungs or may translocate to other organs • Surface area/structure • Smaller particles greater surface area • More chemical reactivity • More sites for cell/protein interaction • Oxidative stresstoxicity, DNA damage, tumors

  23. Toxicological Issues • Scientific basis of toxicology, epidemiology (exposure assessment and risk evaluation) lagging behind • Inherently slower • Long-term effects subject to long latency periods • Production could outpace protections • Not all materials will be problematic

  24. Toxicological Risks • Potential for increased absorption? • Increased absorption and penetration of biological barriers • Ability to reach deep airways • Systemic distribution • Penetrate blood-brain barrier • Potential for new toxicities from engineered nanomaterials?

  25. Toxicity Research • Relatively few studies on engineered nanomaterials • In vitro, isolated cells or tissues • Short-term animal studies, mostly rodents • Direct introduction to the lungs • Studies on related materials • Metal fume • Ultrafine particulates (esp. beryllium) • Mineral fibers

  26. Toxicity Research

  27. Limitations of Current Data • No studies greater than 3 months duration • No dose-response data • No developmental/reproductive studies • No chronic bioassays • Not possible to set health protective limits without assumptions about toxicity relative to that of the same macro-scale material

  28. Industrial Hygiene Issues • Exposure Metrics • Exposure Monitoring • Ventilation Control • Personal Protective Equipment • Respiratory Protection

  29. Exposure Metrics • Nanoparticles may not be suitable for comparison to ‘traditional’ exposure metrics • Mass based metrics may understate exposures • Particle number and/or surface area metrics may be a more reliable indicator of exposure

  30. Exposure Metrics • Some consideration of particle size fractions may be relevant • Number of particles less than 100 nm; 50 nm; 10 nm • One type metric may not be suitable for all

  31. Exposure Metrics • Current research related to beryllium exposure and prevalence of disease indicates traditional metrics (mass per unit volume) may not be protective • Alternative metrics based on particle size, particle number, or particle surface area may be more indicative of risk

  32. Exposure Monitoring • If traditional exposure metrics are not applicable, traditional monitoring methods will not be viable to assess exposure • What Do You Measure?

  33. Exposure Monitoring • There are limited air sampling methods • Real time particle counters / particle sizers • Cascade impactors in the nanoparticle range • High resolution TEM

  34. Three stage nanoparticle cascade impactor capable of proving three particle size fractions - 32, 18 and 10 nm. Source: MSP Corporation Condensation particle counter capable of measuring particles to 10 nm. Source: TSI

  35. Exposure Monitoring • Traditional filter/gravimetric methods cannot be used • 1 µm particle weighs 1,000,000 times more than a 10 nm particle • Larger particles mask the weight of nanoparticles • Mass concentration must be inferred from measured size distribution + number concentration

  36. Exposure Monitoring • An ideal sampler would be able to measure particle surface area and particle number within several size fractions • Such a sampler is not currently available • Most likely monitoring will require using combinations of instruments • Costs are significant

  37. Exposure Monitoring • Personal sampling techniques not readily available • Current research on cutting edge beryllium sampling methods may lead to methods that may have application to nanoparticles • Additional study is needed to more fully characterize and validate the sampling methodologies

  38. Considerations for Control • Nanoparticle behavior will influence control approaches • Behave more like gases • migrate from areas of highest concentration • May agglomerate • Gravitational settling much slower than other particle types • May widely disperse • Re-suspension may be a concern

  39. Considerations for Control • Ultrafine particles in mixtures have been a concern for SH&E professionals • Diesel exhaust fumes • Welding fumes • Carbon black • Dust created in the destruction of the WTC (including asbestos and silica)

  40. Considerations for Control • Applications of exhaust ventilation • Nanoparticles may present the following challenges • Effectiveness of filtration • Design of hoods and enclosures • Capture and transport velocities • Current thinking is that conventional local exhaust ventilation approaches should work • Design must consider both gaseous and particulate behavior

  41. Considerations for Control • Design and installation of ventilation systems based on controlling gas and particulate will provide prudent first steps for worker protection • E.g.; fine wood dust particulates, welding fumes and vapors from stationary sources • Application of design principals based on ACGIH Ventilation Manual

  42. Considerations for Control • Use of respiratory protection • Nanoparticles may present the following challenges • Filtration of ultrafine particulates • Criticality of facial seal for negative pressure respirators • Effectiveness of positive pressure respirators • Appropriateness of fit factors or protection factors

  43. Considerations for Control • Current thinking is that modern respiratory protection technology is sufficient, but more research is needed • New filter media? New materials of construction? • Fit testing methods may require further improvements

  44. Considerations for Control • PPE • Nanoparticles may present the following challenges • Small sized particles may easily penetrate traditional knit clothing • Ocular exposure a concern? • Modern PPE materials of construction will likely provide protection from all but the smallest materials • Ocular protection may present some additional challenges

  45. Considerations for Control • SH&E professionals will be challenged to • evaluate dermal exposure pathways • utilize published guidance in selection of PPE ensembles • develop implementation schemes • assess effectiveness of implementation

  46. Safety Issues • Fire / Explosion Hazards • Composition of nanoparticles • Increased surface area = more easily ignited? • Nanoparticles may persist for longer in the air • Risk could be either greater or smaller

  47. Environmental Issues • Increased concern about releases beyond immediate application / manufacturing site • Consider potential releases via • Take-home exposures • Transport • Manufacturing waste streams • Product waste streams

  48. Environmental Issues • Available pathways to air, soil or water • Little is known about the fate of nanoparticles in the environment • Will such materials be assimilated • How mobile and persistent • What breakdown products may be produced due to environmental transformation/degradation

  49. Prudent workforce protection and occupational health strategies Scientific foundations Appropriate regulation Protective of health Supportive of safe production Model for Action

  50. Scientific Base • Scientific foundation must be built in parallel to prudent workplace measures • Societal obligation to generate and publish scientific findings • Necessary to support policy formulation