title: A Systematic Review of Reported Exposure to Engineered Nanomaterials.
abstract: BACKGROUND
  Engineered nanomaterials (ENMs) have a large economic impact in a range of fields, but the concerns about health and safety of occupational activities involving nanomaterials have not yet been addressed. Monitoring exposure is an important step in risk management. Hence, the interest for reviewing studies that reported a potential for occupational exposure.
  
  
  METHODS
  We systematically searched for studies published between January 2000 and January 2015. We included studies that used a comprehensive method of exposure assessment. Studies were grouped by nanomaterial and categorized as carbonaceous, metallic, or nanoclays. We summarized data on task, monitoring strategy, exposure outcomes, and controls in a narrative way. For each study, the strength of the exposure assessment was evaluated using predetermined criteria. Then, we identified all exposure situations that reported potential occupational exposure based on qualitative or quantitative outcomes. Results were synthesized and general conclusion statements on exposure situations were formulated. The quality of evidence for the conclusion statements was rated as low, moderate, or high depending on the number of confirmed exposure situations, the strength of the exposure assessment, and the consistency of the results.
  
  
  RESULTS
  From the 6403 references initially identified, 220 were selected for full-text screening. From these, 50 studies describing 306 exposure situations in 72 workplaces were eligible for inclusion (27 industrial-scale plants and 45 research or pilot-scale units). There was a potential for exposure to ENMs in 233 of the exposure situations. Exposure occurred in 83% (N = 107) of the situations with carbonaceous ENMs, in 73% (N = 120) of those with metallic ENMs and in 100% (N = 6) of those with nanoclay. Concentrations of elemental carbon in the workers' breathing zone ranged from not detected (ND) to 910 µg m(-3) with local engineering controls (LEC), and from ND to 1000 µg m(-3) without those controls. For carbon nanofibres (CNFs), particle counts ranged from ND to 1.61 CNF structures cm(-3) with LEC, and from 0.09 to 193 CNF structures cm(-3) without those controls. The mass concentrations of aluminium oxide, titanium dioxide, silver, and iron nanoparticles (NPs) were ND, 10-150, 0.24-0.43, and 32 µg m(-3) with LEC, while they were <0.35, non-applicable, 0.09-33, and 335 µg m(-3) without those controls, respectively.
  
  
  CONCLUSIONS
  Regarding the potential of exposure in the workplace, we found high-quality evidence for multiwalled carbon nanotubes (CNTs), single-walled CNTs, CNFs, aluminium oxide, titanium dioxide, and silver NPs; moderate-quality evidence for non-classified CNTs, nanoclays, and iron and silicon dioxide NPs; low-quality evidence for fullerene C60, double-walled CNTs, and zinc oxide NPs; and no evidence for cerium oxide NPs. We found high-quality evidence that potential exposure is most frequently due to handling tasks, that workers are mostly exposed to micro-sized agglomerated NPs, and that engineering controls considerably reduce workers' exposure. There was moderate-quality evidence that workers are exposed in secondary manufacturing industrial-scale plants. There was low-quality evidence that workers are exposed to airborne particles with a size <100nm. There were no studies conducted in low- and middle-income countries.
authors.affiliation: 1.Department of Environmental and Occupational Health, School of Public Health, Institut de recherche en santé publique de l'Université de Montréal (IRSPUM), CP 6128 Succursale Centre-Ville, Montreal, Québec H3C 3J7, Canada; 2.Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505, Boul. de Maisonneuve Ouest, Montreal, Québec H3A 3C2, Canada; maximilien.debia@umontreal.ca.
authors.forename: Maximilien
authors.initials: M
authors.lastname: Debia
authors.affiliation: 1.Department of Environmental and Occupational Health, School of Public Health, Institut de recherche en santé publique de l'Université de Montréal (IRSPUM), CP 6128 Succursale Centre-Ville, Montreal, Québec H3C 3J7, Canada;
authors.forename: Bouchra
authors.initials: B
authors.lastname: Bakhiyi
authors.affiliation: 1.Department of Environmental and Occupational Health, School of Public Health, Institut de recherche en santé publique de l'Université de Montréal (IRSPUM), CP 6128 Succursale Centre-Ville, Montreal, Québec H3C 3J7, Canada; 2.Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), 505, Boul. de Maisonneuve Ouest, Montreal, Québec H3A 3C2, Canada;
authors.forename: Claude
authors.initials: C
authors.lastname: Ostiguy
authors.affiliation: 3. Department of Research and Development in Occupational Health Services, Finnish Institute of Occupational Health, PO Box 93, FIN-70701 Kuopio, Finland;
authors.forename: Jos H
authors.initials: JH
authors.lastname: Verbeek
authors.affiliation: 4.School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 27 St Andrews Road, Parktown 2193, Johannesburg, South Africa;
authors.forename: Derk H
authors.initials: DH
authors.lastname: Brouwer
authors.affiliation: 5.Department of Health and Human Services, National Institute for Occupational Safety and Health (NIOSH), 395 E Street, SW, Patriots Plaza 1, Suite 9200, Washington, DC 20201, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Murashov
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D037742:Nanotubes, Carbon / Q000032:analysis*; D016273:Occupational Exposure / Q000009:adverse effects*; D010316:Particle Size; D018570:Risk Assessment
chemical_list: D000395:Air Pollutants, Occupational; D037742:Nanotubes, Carbon
keywords: exposure assessment; nanomaterial; risk assessment; systematic review