title: Detection of Multi-walled Carbon Nanotubes and Carbon Nanodiscs on Workplace Surfaces at a Small-Scale Producer.
abstract: BACKGROUND
  The industrial use of novel-manufactured nanomaterials such as carbon nanotubes and carbon nanodiscs is increasing globally. Occupational exposure can occur during production, downstream use, and disposal. The health effects of many nanomaterials are not yet fully characterized and to handle nano-objects, their aggregates and agglomerates >100nm (NOAA), a high degree of control measures and personal protective equipment are required. The emission of airborne NOAA during production and handling can contaminate workplace surfaces with dust, which can be resuspended resulting in secondary inhalation exposures and dermal exposures. This study surveys the presence of carbon-based nanomaterials, such as multi-walled carbon nanotubes (MWCNTs) and carbon nanodiscs, as surface contamination at a small-scale producer using a novel tape sampling method.
  
  
  METHODS
  Eighteen different surfaces at a small-scale producer were sampled with an adhesive tape sampling method. The surfaces selected were associated with the production and handling of MWCNT powder in the near-field zone. Surfaces in the far-field zone were also sampled. In addition, tape stripping of the skin was performed on one worker. The tape samples were analysed with scanning electron microscopy to detect the carbon-based NOAA. Air sampling with a personal impactor was also performed on a worker who was producing MWCNTs the same day as the tape samples were collected.
  
  
  RESULTS
  MWCNTs were detected in 50% of the collected tape samples and carbon nanodiscs in 17%. MWCNTs and carbon nanodiscs were identified in all parts of the workplace, thus, increasing the risk for secondary inhalation and dermal exposure of the workers. Both airborne MWCNTs and carbon nanodiscs were detected in the personal impactor samples. The tape-strip samples from the worker showed no presence of carbon-containing nanoparticles.
  
  
  CONCLUSIONS
  Tape sampling is a functional method for detecting surface contamination of carbon-based NOAA and for exposure control during production at potentially any workplace that produces or handles such manufactured nanomaterials. With the tape method, it is possible to monitor if a potential for secondary inhalation exposure or dermal exposure exists through resuspension of dust deposited on workplace surfaces. By means of air sampling, we could confirm that carbon nanodiscs were resuspended into the air at the workplace even though they were not handled during that particular work shift. MWCNTs were detected in the air samples, but can have been derived from either resuspension or from the work tasks with MWCNTs that were performed during the air sampling. Tape sampling is a complementary method to air sampling and together these two methods provide a better view of the hygienic situation in workplaces where NOAA can be emitted into work environments.
authors.affiliation: 1.Division of Occupational and Environmental Medicine, Institute of Laboratory Medicine, Lund University, PO Box 118, SE-22100, Lund, Sweden maria.hedmer@med.lu.se.
authors.forename: Maria
authors.initials: M
authors.lastname: Hedmer
authors.affiliation: 2.Solid State Physics, Lund University, PO Box 118, SE-22100, Lund, Sweden.
authors.forename: Linus
authors.initials: L
authors.lastname: Ludvigsson
authors.affiliation: 3.Ergonomics and Aerosol Technology, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Isaxon
authors.affiliation: 3.Ergonomics and Aerosol Technology, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: Patrik T
authors.initials: PT
authors.lastname: Nilsson
authors.affiliation: 4.National Institute of Occupational Health, PO Box 8149, Dep, N-0033 Oslo, Norway.
authors.forename: Vidar
authors.initials: V
authors.lastname: Skaug
authors.affiliation: 3.Ergonomics and Aerosol Technology, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Bohgard
authors.affiliation: 3.Ergonomics and Aerosol Technology, Lund University, PO Box 118, SE-22100 Lund, Sweden.
authors.forename: Joakim H
authors.initials: JH
authors.lastname: Pagels
authors.affiliation: 2.Solid State Physics, Lund University, PO Box 118, SE-22100, Lund, Sweden.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Messing
authors.affiliation: 1.Division of Occupational and Environmental Medicine, Institute of Laboratory Medicine, Lund University, PO Box 118, SE-22100, Lund, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Tinnerberg
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis; D002244:Carbon / Q000032:analysis*; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring / Q000295:instrumentation*; D006801:Humans; D007221:Industry; D019570:Inhalation Exposure / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000032:analysis*; D016273:Occupational Exposure / Q000032:analysis*; D010316:Particle Size; D017132:Workplace
chemical_list: D000395:Air Pollutants, Occupational; D004391:Dust; D037742:Nanotubes, Carbon; D002244:Carbon
keywords: carbon nanodisc; carbon nanotube; dust; exposure; monitoring; surface contamination; tape sampling; tape stripping; workplace exposure