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Nanomaterials: Are small particles a big problem

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1 Nanomaterials: Are small particles a big problem
Nanomaterials: Are small particles a big problem? Occupational health and safety issues associated with nanoparticle exposures Susan Woskie Professor Department of Work Environment University of Massachusetts Lowell, USA Mahidol University & UMass Lowell Center for Work Environment Nutrition and Development (CWEND) GeoHealth Hub for Occupational & Environmental Health

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3 *over 3000 NM in Nanowerks database
*over 1600 products in Nanotechnology Consumer Products Inventory.

4 Nanomaterial Categories ICON, 2008
Oxides: TiO2, ZnO, CeO2, Fe3O4 MnO2, SiO2 Metals: Ag, Co, Ni, Fe, Pt, Pd, Rh, Au, Al, Cu Carbon Based Nanoparticles Nanotubes….single & multiwall Nano Carbon black Quantum Dots: fluorescent crystalline semiconductor nanoparticles for biolabels, LEDs, solar cells Macromolecules: hyperbranched polymeric organic molecules for drug delivery, coatings, ion exchange resins

5 Kosnett & Woskie Chap 81 Patty’s Industrial Toxicology 2012

6 Nano Silver…antibacterial
Used in many commerical products Athletic clothing, linens, cosmetics, baby bottles, toothpaste, food containers, kitchen and washing machine surfaces & sprayed in Hong Kong subways Used in many medical productes Hospital equipment including catheters, bandages, wheelchair seats and door handles. Concern about bacterial resistance and damage to sewage treatment bacteria Unconverted silver shown to be toxic to fish, algae and crustaceans. Some converted to more stable silver sulfides in wastewater (O2-free environments where sulfates present)

7 Oberdoster et al. EHP 2005; 113 (7)

8 Translocation via olfactory neurons (Oberdoster, EHP, 2005)
There is clear evidence that particles can travel via the olfactory neurons and can get past the blood-brain barrier. Skin is a major route and a major concern, considering the issue of how many products with nanoparticles are cosmetic. There is clear evidence that smaller particles penetrate skin. Dr. Sally Tinkle from NIEHS has found it in they get through the epidermis and into the dermis. -non-human primates :monkey & 50 nm colloidal gold particles (DeLorenzo, 1970) -rodents: ultrafine particles ~30 nm (G. Oberdörster 1990s) - rodents & cats: axonal transport nm rhodamine labeled microspheres (Katz et al. 1983) -fish: soluble Mn (Tjalve, 1990s)

9 Reactive Oxygen Species /ROS Cause Oxidative Damage
Chronic Inflammation- Linked to various diseases Reactive Oxygen Species /ROS Cause Oxidative Damage

10 Nanoparticle Emissions from Commercial Photocopiers
Bello et al Nanotoxicology, 2013 (5):989

11 Biomarkers in Nasal Lavage
GCSF IL6 0 6hr 12hr 24hr 10 key inflammatory markers increased, such as: IL-6, IL-8, TNF-a, GCSF, MCP-1 Total Protein UP PMN (white blood cells) UP Several inflammatory markers stay significantly elevated at hrs post-exposure (IL-6, IL-8, EGF and fractalkine) IL8 TNF-a Key inflammatory cytokines/chemokines go up and take longer than 24 hrs post exposure to clear. Potential buildup of response from day-to-day. PMN Khatri et al Nanotoxicology, 2013 Aug;7(5):1014

12 8-OHdG – Sensitive Marker of Systemic Oxidative Damage from Photocopier Exposure
Excreted in Urine hr hr hr 8-OH-dG (oxidative state of deoxyguanine DNA amino acid) increased in urine after photocopier exposure Stays significantly elevated at hrs post-exposure Increases with average daily particle count (#/cm3) Partilce count of ~30,000 is ~10x higher than background ln 8-OHDG Av Daily Particle count Khatri et al Nanotoxicology, 2013

13 Reactive Oxygen Species /ROS Cause Oxidative Damage
We need Epidemiologic Studies of NM Exposed Workers….NIOSH has proposed a prospective cohort Reactive Oxygen Species /ROS Cause Oxidative Damage

14 Tagaki et al “Induction of mesothelioma in p53+/− mouse by intraperitoneal application of multi-wall carbon nanotube”: Administer MWCNT intraperitoneally to asbestos sensitive mice. MWCNT induced mesothelioma (purple line) as did positive control, crocidolite asbestos (orange line), compared to no mesothelioma from fullerene negative control. MWCNT ~10 to 20 micrometers length with an aspect ratio of more than three…..asbestos fiber-like J. Toxicol. Sci., Vol. 33: No. 1, (2008) .

15 Fiber Production with Machining of Composites
Cutting of CNT-hybrid composites produced respirable size fibers (though not specifically CNTs) Using NIOSH counting rules the concentrations of fibers were: fibers/cm3 (0.1 f/cm3 = USA PEL) CNT-Alumina composites produced fewer fibers than CNT-carbon composites Bello et al, J Nanopart Res 2009

16 Examples of Potential Exposures
Trainer Notes: [Discuss the examples of potential exposures and make the point that these are mostly research scale and not large production units.] Some Photos courtesy of M. Methner, NIOSH 3-16

17 PRIMARY MANUFACTURING TiO2
Thousands of tons/yr. Scenario 1: Nano anatase TiO2 production: problems similar to respirable dust. Traditional approaches may work fine. X2012;

18 off-line Characterization
P. Boonruksa UML 2014 Instrumentation Real time Characterization Integrated Sampling off-line Characterization Number Concentration Fast Mobility Particle Sizer (FMPS), Aerodynamic Particle Sizer (APS), Condensation Particle Counter (CPC)(p/cm3) Size distribution FMPS, APS (dN/dLogDp, p/cm3) NIOSH NEAT screening…. if process < 25% background count then stop… If process > 25% background then further samples

19 Instrumentation Real time Integrated Sampling Characterization
off-line Morphology ESP TEM Filters SEM/EDX Chemical composite TGA CNT content XPS Surface chem. Fiber Count, Shape (BZ) Filters SEM 200-mesh Cu with C film Electrostatic precipitator (ESP) Nucleopore, 0.4 um Thermal Gravimetric Analysis (TGA) Xray Photoelectron Spectroscopy (XPS) P. Boonruksa UML 2014

20 REGULATIONS: RELs International USA (NIOSH) CNTs
No standard or criteria for counting potential CNT fibers, (now use asbestos fiber count method, NIOSH 7400, 7402, WHO 1997) USA (NIOSH) International CNTs NIOSH, 1ug/m3, EC, 8-hr TWA (asbestos = 0.1 f/cc) Nano TiO2 300 ug/m3, 8-TWA (vs. 2.4mg/m3 for non-nano TiO2) CNTs 0.01 fibers/cm3 (British Stand Inst 2007, German Social Accident Insurance IFA 2009) 30 ug/m3 (Japanese National Institute of Advanced Industrial Science and Technology) Consider ALARA: As Low As Reasonably Achievable.

21 Precautionary Principle United Nations Rio Declaration 1992
Lack of full scientific certainty shall not be used to postpone measures to prevent threats of serious or irreversible damage to the environment or human health spinning operations for asbestos thread (1930–1960) and spinning SWCNT into high-strength ‘super rope’ (early 2000s)

22 Engineering Controls LEV during reactor cleanout reduces exposures 74-96% (Methner JOEH 2008) ICON survey reported only 47% of those handling dry powder use lab hood or ventilation Over Background Particle Counts Transfer Al2O3 Tsai et al Ann Occ Hyg 2010

23 Controls for Nano Exposures
Respiratory Protection Program Requirements NIOSH approved P100/N95 filters “achieve expected levels of filtration efficiency for nanoparticles” (NIOSH-allowed penetration levels of < 5% N95 and < 0.03% P100 filter materials) Dermal Exposure & PPE Nitrile, latex, neoprene, and butyl rubber gloves tested with powder and colloidal nano TiO2 by IRRST Canada 2013. Generally good protection but replace gloves used under mechanically stressful conditions, especially if colloidal material Training 42% of 82 International nano companies reported they did not perceive nanomaterials as risky so they : Did have not nano specific training or EHS program (64%) Did not require PPE (40%) Did not do exposure monitoring (51%) Did not use nanospecific waste disposal methods (47%) Conti et al. EST 2008, 42 (9)

24 Next generation ENM: Safer-by design
Incorporate high throughput screening prior to marketing Utilize screening to design safer materials Sotiriou et al., Curr Opin Chem Eng 2011, 1, 3 – 10 Xia et al., ACS Nano 2011, 5, 1223 – 1235 Napierska et al., Particle and Fibre Toxicology 2010, 7,39 Teleki et al., Chem. Mater. 2009, 21, 2094–2100 Sotiriou et al., Adv. Funct. Mater. 2010, 20, 4250–4257 Source: Prof. P. Demokritou HSPH

25 Thank You for your Attention!
Sunscreens, ZnO nano vs macro Macrophage with carbon nanotube Q-Dots Larson, Science, 2003, 300:1434 Hardman, EHP 2006, 114 (2)


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