Ultrafine and Nano-Size Welding Fume Exposure Assessment: Size, Shape and Chemical Characterization

Details

• Personal Author:
  Breskey JD
• Description:
  Occupational exposures to welding fume have been associated with numerous respiratory and non-respiratory health effects, however, clear toxicological mechanisms and dose-response relationships have yet to be elucidated due to poor fume exposure characterization in epidemiological studies. Recent particle toxicology research has highlighted the potential for greater adverse effects associated with sub-micron particles as compared to larger particles on a mass dose basis. Because welding fume is composed of primarily small particles (greater than 95% of the fume mass contained in particles smaller than one micron) an in depth characterization of the particle size fractions of welding fume aerosol was performed in a laboratory controlled environment to provide relevant data in order to link exposure properties to adverse health outcomes. Characterization methods included the measurement of mass-based and count-based particle size distribution parameters using cascade impactor samplers, calculation of inherent electronic charge per particle using the electronic low pressure impactor, determination of elemental composition of distinct size-fractions of the aerosol using inductively coupled plasma mass spectroscopy, and the evaluation of the primary particle size and agglomerated particle morphology using electron microscopy. In contrast to previous laboratory based welding fume characterization studies that often capture fume in purely emission based systems, this work uniquely characterizes fume size-fractions in both an emission system and an exposure system in which a breathing manikin is employed to represent a realistic exposure scenario. Results demonstrated that welding fume consistently exhibits a bimodal lognormal particle size distribution in both the emission system and exposure system indicating that exposure characterization from emission type systems may adequately represent welding scenarios found in occupational environments. Further, chemical analysis revealed the alkali metal content of size-fractionated samples was correlated with hexavalent chromium content in particle sizes between 0.1 and 1.0 micrometer. Distinct primary particle size ranges and morphologically descriptive groups were defined, however, microscopic characterization of fume samples collected within the breathing- zone proved difficult due to high particle number concentrations. [Description provided by NIOSH]
• Subjects:
  Occupational Exposure Occupational Health Safety Toxicology Welding
• Keywords:
  Breathing Zone Dose Response Nanoparticles Occupational Exposure Particle Counters Particle Size Analysis Toxicopathology Welding Fumes
• ISBN:
  9781124863733
• Publisher:
  ProQuest LLC.
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Thesis
• Place as Subject:
  Illinois ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20056632
• Citation:
  Ann Arbor, MI: ProQuest LLC., 2011 Sep; :3472448
• Federal Fiscal Year:
  2011
• Performing Organization:
  University of Illinois at Chicago
• Peer Reviewed:
  False
• Start Date:
  20050801
• Source Full Name:
  Ultrafine and nano-size welding fume exposure assessment: size, shape and chemical characterization
• End Date:
  20090731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:25c505daacbecd7559675999aacae2eee47788946b73e255941bcbf1ef0112cc8deb2e987577070bbdee0b01d2ffdfb5a8d9909a4840daf8e3bf9db4a9898f78
• Download URL:
  https://stacks.cdc.gov/view/cdc/214195/cdc_214195_DS1.pdf
• File Type:
  [PDF - 14.55 MB ]