Exposure to Nanomaterials:

Transcription

1 Exposure to Nanomaterials: Challenges and Lessons form the Workplace Charles L. Geraci, Ph.D., CIH Centers for Disease Control and Prevention National Institute for Occupational Safety and Health Toward Regulation of Nanomaterials University of Notre Dame May 10-12, 2010 The findings and conclusions in this presentation have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy

2 NIOSH Mission Overall: Conduct research and develop recommendations that assure safe and healthful working conditions for all working men and women. Nanotechnology: Responsible development of the technology by investigating the implications and applications; potential human health hazards of nanomaterials; developing interventions; an deploying guidance globally

3 Overview Background Update on NIOSH activities and results Other significant happenings Summary of NIOSH research Hazards of Nanomaterials Exposure potential Practices and controls Risk management Take a look at the Big Picture

4 Why the Workplace? First point of potential exposure Exposure concentration greatest Early in the history of a material Workplace = R&D, Scale Up/Pilot, Manufacture, Use, Disposal Workers are at the point, regardless of the intended use of the product.

5 The Focus: Free Engineered Nanoscale Particulate Matter Nanoparticles Not firmly attached to a surface Not part of a bigger item (e.g., microchip, cell wall) Can result in exposure via inhalation, skin absorption or ingestion

6 What is getting attention? Carbon Nanotubes. Graphene Nano metals/oxides Silver, TiO2, Gold Quantum dots Nano-enabled materials, Nano-bio anything, NEMS But.. How much OS&H information is being generated?

7 Occupationally Relevant Research is Lagging Peer Reviewed Nano Environment, Health and Safety Journal Articles All EHS Occupational Health Less than 6% of all nano impacts research is of high occupational relevance All = All published research relating to the potential environmental, health and safety effects of nanomaterials Occupational Health = e.g., efficacy of gloves, respirators; workplace exposure assessment SOURCE: ICON Virtual Journal of Nano Environment, Health and Safety 7

8 Lack of Nanomaterial Exposure Data Hinders Risk Management Efforts Peer Reviewed Nano Environment, Health and Safety Journal Articles Hazard Exposure In the last decade hazard studies outnumbered exposure studies by a margin of 4:1 SOURCE: ICON Virtual Journal of Nano Environment, Health and Safety 8

9 Basis for Concern about Health and Safety Effects of Nanoparticles Initial animal inhalation studies of engineered nanomaterials Pulmonary fibrosis, granulomas, and inflammation (early onset, persistent) Question about lung cancer, mesothelioma-like effects? Cardiovascular effects: oxidative stress, plaque build up Nanomaterials have been shown to Translocate from nose to brain Translocate from lungs to most organ systems Have potential for skin penetration

10 What is needed? An organized research program that is patterned after the risk assessment an management model Understand the hazard Toxicology Characterize the hazard Risk assessment and Material and Process evaluaton Evaluate exposure Exposure measurements Characterize the risk Measure dose (exposure) and Risk assessment Risk Management

11 The NIOSH Nanotechnology Research Center focus areas

12 Key Elements of Risk Management Hazard Identification Is there reason to believe this could be harmful? Hazard Nanotoxicology What do we know? Are there trends? Exposure Assessment Will there be exposure in realworld conditions? Risk Characterization Is substance hazardous and will there be exposure? Risk Management Develop procedures to minimize exposures

13 Nanotoxicology: Key Findings Pulmonary exposure to: Carbon nanotubes causes rapid and persistent fibrosis in mice Certain nanoparticles (SWCNT or TiO 2 ) can cause cardiovascular dysfunction Courtesy of R. Mercer, NIOSH MWCNT or TiO 2 nanowires can induce inflammatory mediators in certain regions of the brain

14 Nanotoxicology: Key Findings Carbon nanotubes Multi-walled nanotubes can reach the intrapleural space (site of mesotheliomia) Single-walled nanotubes can interfere with cell division Courtesy of R. Mercer, NIOSH

15 Key Elements of Risk Management Hazard Identification Is there reason to believe this could be harmful? Exposure Can it be measured? Where is it occurring? Metric? Exposure Assessment Will there be exposure in realworld conditions? Risk Characterization Is substance hazardous and will there be exposure? Risk Management Develop procedures to minimize exposures

16 Diverse Exposure Scenarios Evaluated

17 Examples of Potential Exposures Photos courtesy of M. Methner, NIOSH: with permission.

18 Evidence of Exposure

19 Evidence of Exposure Weighing MWCNT s PBZ sample collected on a polycarbonate filter and analyzed by SEM

20 Evidence of Exposure Harvesting SWCNT s, scraping product from wall of Carbon Arc Reactor Task-based At source air sample

21 Type of Facility Examples of NIOSH field investigations Type of Particle, Morphology Size of Particle University Research lab Carbon Nanofibers Approx. 100 nm diameter, 1 10 microns long Range of Potential Exposure Concentrations µg/m 3 Total Carbon Metal Oxide Manufacturer TiO 2, Lithium Titanate, powder nm <100 nm: 1.4 µg/m 3 (TiO 2 ) Total dust: µg/m 3 (TiO 2 ) <100 nm: ND (Li) Total dust: ND -3 µg/m 3 (Li) Manufacturer Carbon Nanofibers Approx. 100 nm diameter, 1 10 microns long µg/m 3 Total carbon Research and Development lab Quantum Dots, spheres 2 8 nm ND Metal Oxide Manufacturer Manganese, Silver, Nickel, Cobalt, Iron oxides, spheres 8 50 nm µg/m 3 Mg, Ag, Ni, Co, Fe Research and Development lab (Pilot- Scale) Aluminum, spheres nm µg/m 3 Al Research and Development lab Elemental metals: Silver, nm ND copper, TiO 2 Filter Media Manufacturer Nylon 6 Nanofiber nm diameter, continuous length ND

22 Recent published summary of field exposure assessments Nanoparticle Emission Assessment Technique (NEAT) for the Identification and Measurement of Potential Inhalation Exposure to Engineered Nanomaterials Part A and Part B: Results from 12 Field Studies M. Methner, L. Hodson, C. Geraci National Institute for Occupational Safety and Health (NIOSH), Nanotechnology Research Center, Cincinnati, Ohio Journal of Occupational and Environmental Hygiene March 2010

23 Key Elements of Risk Management Hazard Identification Is there reason to believe this could be harmful? Exposure Assessment Will there be exposure in realworld conditions? Risk Hazard x Exposure. Risk Characterization Is substance hazardous and will there be exposure? Risk Management Develop procedures to minimize exposures

24 Risk Assessment: Ultrafine (Nano) TiO 2 NIOSH draft recommended exposure limits (RELs): 1.5 mg/m3 fine TiO2; 0.2 mg/m3 ultrafine TiO2 Reflects greater inflammation & tumor risk of ultrafine on mass basis This recommendation will be released from NIOSH in the Spring of 2010 after two years of review. - Key Message- The OEL for a material in its large form may not be appropriate for the Nano form

25 Hazard and Risk Picture - Carbon Nanotubes SWCNTs more fibrogenic than an equal mass of ultrafine carbon black or fine quartz. Doses approximated exposure at the PEL for graphite (5 mg/m3) for 20 days MWCNT can penetrate the pleura more data needed Similar message: the OEL for the large form of carbon is not appropriate for the nano form. Key NIOSH Project: Current Intelligence Bulletin on Carbon Nanotubes. Key responses: Industry OELs

26 Key Elements of Risk Management Hazard Identification Is there reason to believe this could be harmful? Controls Exposure Assessment Will there be exposure in realworld conditions? What works? What has been used? What can be reapplied? Risk Characterization Is substance hazardous and will there be exposure? Risk Management Develop procedures to minimize exposures

27 Controls for Laboratory-Scale Work Effective controls that factor budget and space limitations are available Select controls based on taskbased exposure risks

28 Larger Scale Mixing of carbon nanofibers inside ventilated enclosure (face of opening is covered in plastic strips for easy access). Air is drawn underneath plastic strips and up to ceiling exhaust vents. Photo courtesy of Mark Methner, PhD, CIH, NIOSH

29 Global Collaboration ISO, OECD Canada IRSST Health Canada UK HSE, HSL UN, WHO EU NanoImpactNet NIOSH Australia Switzerland IST Japan JNIOSH Other Institutes

30 Basic Guidance from NIOSH Updated and reissued in 2009 Based on direct experience and applied research results Updated as new information is developed A starting point for building a responsible nanomaterial management program

31 Global Outreach: the GoodNanoGuide Protected Internet site on occupational practices for the safe handling of nanomaterials Multiple stakeholders contribute, share and discuss information Modern, interactive, up-to-date

32 The Good News Long history of working in the grey zone Many solutions exist and can be reapplied Experience-based approach works Collaboration is actually happening Many existing frameworks can be used The above allows focus on new/unique issues Creative approaches being explored: Control Banding We know how to do a lot of this already

33 Nanotechnology: Summary More than 1,000 nano enabled products already in commerce. Hazards of nanomaterials are still not clear NIOSH is conducting research and developing guidelines on occupational exposures Research Toxicology of nanoparticles Measurement methods Controls and worker protection Guidance Exposure assessment Control technologies Medical screening and surveillance Exposure registries Epidemiologic studies Developing document on CNTs

34 Thank you!