Presentation on theme: "Nanomaterials: Are small particles a big problem"— Presentation transcript:
1 Nanomaterials: Are small particles a big problem Nanomaterials: Are small particles a big problem? Occupational health and safety issues associated with nanoparticle exposuresSusan WoskieProfessorDepartment of Work EnvironmentUniversity of Massachusetts Lowell, USAMahidol University & UMass LowellCenter for Work Environment Nutrition and Development (CWEND)GeoHealth Hub for Occupational & Environmental Health
6 Nano Silver…antibacterial Used in many commerical productsAthletic clothing, linens, cosmetics, baby bottles, toothpaste, food containers, kitchen and washing machine surfaces & sprayed in Hong Kong subwaysUsed in many medical productesHospital equipment including catheters, bandages, wheelchair seats and door handles.Concern about bacterial resistance and damage to sewage treatment bacteriaUnconverted 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)
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 diseasesReactive Oxygen Species /ROSCause Oxidative Damage
10 Nanoparticle Emissions from Commercial Photocopiers Bello et al Nanotoxicology, 2013 (5):989
11 Biomarkers in Nasal Lavage GCSFIL60 6hr 12hr 24hr10 key inflammatory markers increased, such as:IL-6, IL-8, TNF-a, GCSF, MCP-1Total Protein UPPMN (white blood cells) UPSeveral inflammatory markers stay significantly elevated at hrs post-exposure (IL-6, IL-8, EGF and fractalkine)IL8TNF-aKey inflammatory cytokines/chemokines go up and take longer than 24 hrs post exposure to clear. Potential buildup of response from day-to-day.PMNKhatri et al Nanotoxicology,2013 Aug;7(5):1014
12 8-OHdG – Sensitive Marker of Systemic Oxidative Damage from Photocopier Exposure Excreted in Urinehr hr hr8-OH-dG (oxidative state of deoxyguanine DNA amino acid) increased in urine after photocopier exposureStays significantly elevated at hrs post-exposureIncreases with average daily particle count (#/cm3)Partilce count of ~30,000 is ~10x higher than backgroundln 8-OHDGAv Daily Particle countKhatri et al Nanotoxicology, 2013
13 Reactive Oxygen Species /ROS Cause Oxidative Damage We need Epidemiologic Studies of NM ExposedWorkers….NIOSH has proposed a prospective cohortReactive Oxygen Species /ROSCause 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-likeJ. 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 compositesBello 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, NIOSH3-16
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 2014InstrumentationReal timeCharacterizationIntegrated Samplingoff-line CharacterizationNumber ConcentrationFast Mobility Particle Sizer (FMPS), Aerodynamic Particle Sizer (APS), Condensation Particle Counter (CPC)(p/cm3)Size distributionFMPS, 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-lineMorphologyESP TEMFilters SEM/EDXChemical compositeTGA CNT contentXPS Surface chem.Fiber Count, Shape (BZ)Filters SEM200-mesh Cu with C filmElectrostatic precipitator (ESP)Nucleopore, 0.4 umThermal 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)InternationalCNTsNIOSH, 1ug/m3, EC, 8-hr TWA(asbestos = 0.1 f/cc)Nano TiO2300 ug/m3, 8-TWA (vs. 2.4mg/m3 for non-nano TiO2)CNTs0.01 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 healthspinning operations for asbestos thread (1930–1960) and spinning SWCNT into high-strength ‘super rope’ (early 2000s)
22 Engineering ControlsLEV during reactor cleanout reduces exposures 74-96% (Methner JOEH 2008)ICON survey reported only 47% of those handling dry powder use lab hood or ventilationOver BackgroundParticle CountsTransfer Al2O3Tsai et al Ann Occ Hyg 2010
23 Controls for Nano Exposures Respiratory Protection Program RequirementsNIOSH 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 & PPENitrile, 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 materialTraining42% 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 marketingUtilize screening to design safer materialsSotiriou et al., Curr Opin Chem Eng 2011, 1, 3 – 10Xia et al., ACS Nano 2011, 5, 1223 – 1235Napierska et al., Particle and Fibre Toxicology 2010, 7,39Teleki et al., Chem. Mater. 2009, 21, 2094–2100Sotiriou et al., Adv. Funct. Mater. 2010, 20, 4250–4257Source: Prof. P. Demokritou HSPH
25 Thank You for your Attention! Sunscreens, ZnO nano vs macroMacrophage with carbon nanotubeQ-DotsLarson, Science, 2003, 300:1434Hardman, EHP 2006, 114 (2)
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