Characterization of Hard Metal Husts from Sintering and Detonation Coating Processes and Comparative Hydroxyl Radical Production

Details

• Personal Author:
  Harrison JC ; Hornsby-Myers JL ; Keane MJ ; Myers, John R. ; Stephens JW ; Wallace WE
• Description:
  Dust samples from sintering and detonation coating hard-metal processes were characterized, compared, and contrasted for morphology, composition, and generation of hydroxyl radicals. Inhalation of respirable hard-metal (sintered carbide) dusts from hard-metal processes is known to cause fibrotic and asthmatic lung disease. Scanning electron microscopy/energy-dispersive X-ray analysis was used for morphology, composition, and elemental distribution. An electron spin resonance (ESR) spin trapping technique was used to detect hydroxyl radical generation. Samples were incubated with air-saturated buffer solutions containing a spin trap and analyzed by ESR for the presence of *OH in solution. Postdetonation coating samples often had surface contamination of Co on the WC particles, as shown by elemental mapping of individual particles; this was not evident in predetonation samples or unsintered materials in this study. ESR measurements show that both detonation-gun materials were capable of generating *OH , while the WC, cobalt, and presintered mixture did not produce detectable amounts of *OH radicals. The DMPO/*OH adduct formation was apparently facilitated by Fe-mediated reactions for predetonation dusts, and by Fe-mediated site-specific reactions for postdetonation dusts. The overspray materials from the detonation-gun process produced 9-fold more *OH radicals than the predetonation coating mixture. Overall, this study indicates there are substantial differences between postdetonation materials and both predetonation and unsintered hard-metal process materials with respect to morphology, elemental distribution, and *OH radical generation reactions and that these differences may be important in the toxic potential of those materials. [Description provided by NIOSH]
• Subjects:
  Dust Laboratories Occupational Health Safety
• Keywords:
  Carbides Dust-exposure Dust-inhalation Dust-sampling Dusts Hard-metals Hydroxyl-groups Laboratory-techniques
• ISSN:
  0893-228X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; DSR - Division of Safety Research
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  15
• Issue:
  8
• NIOSHTIC Number:
  nn:20022940
• Citation:
  Chem Res Toxicol 2002 Aug; 15(8):1010-1016
• Contact Point Address:
  Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA
• CAS Registry Number:
  Hydroxyl (CAS RN 3352-57-6)
• Federal Fiscal Year:
  2002
• Peer Reviewed:
  True
• Source Full Name:
  Chemical Research in Toxicology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:12175a9d1e8921af05f7701e9042bccb78e7b012ff86a30610b51f61c530c4697d89ba981167a8d5b83fc9412a6af8598f4d5e861352b519a7f1e5afef87810e
• Download URL:
  https://stacks.cdc.gov/view/cdc/199546/cdc_199546_DS1.pdf
• File Type:
  [PDF - 153.19 KB ]