Nanotechnology and Exposure: The Pathway to a Safe and Healthy Environment Professor Candace Tsai Colorado State University Bogotá, 14-15 FEB 2017
Nanotechnology and Nanomaterials
Engineered Nanoparticles- Intentional Materials Carbon black Carbon nanotube Titanium dioxide 20 nm
Lee et al. ACS Nano 4(7) 2010 4
Ref: Canada NanoPortal Nanomaterials is released and distributed into water and air Environmental transformations of nanomaterials cause complicated exposure and effect Ref: Lowry, et al., ES&T, 2012, 46(13), 6893 5
Nanomaterials use in wastewater treatment Iron oxide nanomaterials Carbon nanotubes (CNT) Nanomaterials use for water purification Use carbon nanotubes to remove microorganisms from large quantities of water quickly, provide drinking water for astronauts. Ref: Nasa website 6
CNT Properties and Application flexible carbon nanotube battery High electrical conductivity High thermal conductivity Very high tensile strength Highly flexible High surface to volume ratio!..and more Nanotube Textile CNTs expand epoxy applications 7
Nanoparticles at beach Ref: National Geographic, May 2015 Nanoparticles (Titanium dioxides, TiO 2 ) used in sunscreens and other consumer products may harm marine creatures by disabling the defense mechanisms that protect their embryos. 8
Nanoparticles for newborn? Needle-like particles of hydroxyapatite found in infant formula by researchers. 9 Westerhoff and Schoepf/ASU, CC BY-ND
Effect to fetus? Drug delivery Inhalation, injection or ingestion 10
Exposure at Workplaces 11
Inhalation Exposure Pleura 13
From Respiratory Tract to Brain
Human Exposure Case Ref: 2014, American J of Industrial Medicine, Journeay and Goldman A chemist formulated polymers and coatings usually using silver ink particles. When she later began working with nickel nanoparticle powder weighed out and handled on a lab bench with no protective measures, she developed throat irritation, nasal congestion, post nasal drip, facial flushing, and.. This incident triggered the company to make plans for better control measures for working with nickel nanoparticles. 16
Some nanoparticles are potential carcinogens 17
International Agency for Research on Cancer (IARC) classified Multiwalled Carbon Nanotubes (MWCNT) type 7 and TiO 2 as 2B carcinogens in 2014. 18
CNT in children s lung in Paris Ref: Kolosnjaj-Tabi, EBioMedicin, 2015 19
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Exposure Assessment 21
Invisible Airborne Particles 100 nm Nanoalumina particle 45 nm Nanoalumina 22 22 22
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Sampling Technique TEM grid (diameter 3.05 mm), Air stream Polycarbonate filter, 0.2µm pore (diameter 25 mm) Bottom support Pump Cassette base Tsai diffusion sampler (TDS) o Operated at low flowrate of 0.3L/min. o Collected nanoparticles on grid by Brownian motion. o Analyze particles using SEM on filter and TEM on grid. 26
Exposure Control and Protection 27
Laboratory fume hood 28 o Airflow pattern is the major issue to cause exposure. o Nanoparticles behave like a gas. o Proper controls are necessary and important. Publication: Tsai et al. JNR 2009; Tsai et al. Annals of Occu H, 2010; Tsai, JNR 2013.
oexposure from manufacturing and cutting nanocomposites ocontrols to reduce exposure omaterial property test 29
Near-field, source Far-field, 2 nd port Air velocity at 2 nd port, 0.74m away from the enclosure open slot, was reduced to 67 ft/min from 2400 ft/min. Silverman equation V ( x) Tsai et al., AAQR, 2008. Tsai et al., NANO, 2008. Ashter et al., Polymer Eng. Sci. J.,2009. Tsai et al., JNR, 2012 3.7 Q Lx 30
Isolation Ventilation Filtration Hopper & Enclosure 2 nd port o Exposure studied at near field and far field o Isolation significantly reduced particle escape o Enclosure and modified airflow/air velocity controlled exposure o Emission during processing at 2 nd port contain individual particle
Protective Clothing? 32
(c) Polyester fabric (e) (d) (f) Polyester (c, d) and Tyvek (e, f) fabric contaminated with nanoalumina particles Improve property of fabric fiber to peel off nanoparticle Tyvek fabric Tsai, S., Contamination and Release of Nanomaterials Associated with the Use of Personal Protective Clothing, Annals of Occupational Hygiene, 2015, 1-13 33
Regulations and Actions 34
Toxic Substance Control Act (TSCA) reporting Ref: US EPA 2017 Final rule for Chemical Substances When Manufactured or Processed as Nanoscale Materials 35
US National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limits (REL) Carbon nanotubes 1 μg/m 3 (2013) As measured by NIOSH 5040 (elemental carbon) Based on Limit of Quantification (LOQ) UK British Standard Institute (BSI) Occupational Exposure Limit (OEL), Swiss Accident Insurance Funds, German Institute for Occupational Safety and Health Carbon nanotube 0.01 fibers/cm3 As measured by scanning or transmission electron microscopy SEM/TEM Japan OEL 30 g/m 3 for SWCNT, 80 g/m 3 MWCNT Based on no observed effect levels (NOELs)
Active non-profit organizations American Industrial Hygiene Association (AIHA), Nanotechnology Working Group Sustainable Nanotechnology Organization (SNO) GoodNanoGuide, https://nanohub.org/groups/gng 37
Question? Dr. Candace Tsai, Candace.Tsai@colostate.edu