Presentation on theme: "Nanomaterials: Are small particles a big problem? Occupational health and safety issues associated with nanoparticle exposures Susan Woskie Professor Department."— Presentation transcript:
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 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
3 *over 3000 NM in Nanowerks database *over 1600 products in Nanotechnology Consumer Products Inventory.
Nanomaterial Categories ICON, 2008 Oxides: TiO 2, ZnO, CeO 2, Fe 3 O 4 MnO 2, SiO 2 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
Kosnett & Woskie Chap 81 Patty’s Industrial Toxicology 2012
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 (O 2 - free environments where sulfates present)
Chronic Inflammation- Linked to various diseases Reactive Oxygen Species /ROS Cause Oxidative Damage
Bello et al Nanotoxicology, 2013 (5): Nanoparticle Emissions from Commercial Photocopiers
Biomarkers in Nasal Lavage Khatri et al Nanotoxicology, 2013 Aug;7(5): 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) 0 6hr 12hr 24hr IL6 GCSF IL8TNF-a PMN
Excreted in Urine 8-OHdG – Sensitive Marker of Systemic Oxidative Damage from Photocopier Exposure 12 ln 8-OHDG 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 0 6hr 12hr 24hr Av Daily Particle count Khatri et al Nanotoxicology, 2013
We need Epidemiologic Studies of NM Exposed Workers…. NIOSH has proposed a prospective cohort Reactive Oxygen Species /ROS Cause Oxidative Damage
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).
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/cm 3 (0.1 f/cm3 = USA PEL) CNT-Alumina composites produced fewer fibers than CNT-carbon composites Bello et al, J Nanopart Res 2009
Examples of Potential Exposures Some Photos courtesy of M. Methner, NIOSH 3-16
X2012; 17 PRIMARY MANUFACTURING TiO 2 Thousands of tons/yr.
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/cm 3 ) Size distribution FMPS, APS (dN/dLogDp, p/cm 3 ) 18 P. Boonruksa UML 2014 NIOSH NEAT screening…. if process < 25% background count then stop… If process > 25% background then further samples
Instrumentation Real time Characterization Integrated Sampling off-line Characterization 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 Nucleopore, 0.4 um Thermal Gravimetric Analysis (TGA) Xray Photoelectron Spectroscopy (XPS) P. Boonruksa UML 2014 Electrostatic precipitator (ESP )
REGULATIONS: RELs USA (NIOSH) CNTs –NIOSH, 1ug/m3, EC, 8-hr TWA –(asbestos = 0.1 f/cc) Nano TiO 2 – 300 ug/m 3, 8-TWA (vs. 2.4mg/m3 for non- nano TiO 2 ) International CNTs –0.01 fibers/cm 3 (British Stand Inst 2007, German Social Accident Insurance IFA 2009) –30 ug/m 3 (Japanese National Institute of Advanced Industrial Science and Technology) 20 No standard or criteria for counting potential CNT fibers, (now use asbestos fiber count method, NIOSH 7400, 7402, WHO 1997) Consider ALARA: As Low As Reasonably Achievable.
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)
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 Particle Counts Over Background Transfer Al 2 O 3 Tsai et al Ann Occ Hyg 2010
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 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)
(1)Sotiriou et al., Curr Opin Chem Eng 2011, 1, 3 – 10 (2)Xia et al., ACS Nano 2011, 5, 1223 – 1235 (3)Napierska et al., Particle and Fibre Toxicology 2010, 7,39 (4)Teleki et al., Chem. Mater. 2009, 21, 2094–2100 (5)Sotiriou et al., Adv. Funct. Mater. 2010, 20, 4250–4257 Source: Prof. P. Demokritou HSPH Next generation ENM: Safer-by design Incorporate high throughput screening prior to marketing Utilize screening to design safer materials
Thank You for your Attention! Sunscreens, ZnO nano vs macro 25 Q-Dots products/cosmetics-and-sunscreen/ Larson, Science, 2003, 300:1434 Hardman, EHP 2006, 114 (2) Macrophage with carbon nanotube