Release of Crystalline Silica Nanoparticles During Engineered Stone Fabrication

Details

• Personal Author:
  Dozier, Alan K. ; Ku BK ; Kulkarni P ; Qi C ; Rishi K ; Thompson D ; Vogiazi V ; Wang C ; Zervaki O
• Description:
  Inhalation exposure to respirable crystalline silica (RCS) during the fabrication of engineered stone-based kitchen countertops has been on the rise in recent years and has become a significant occupational health problem in the United States and globally. Little is known about the presence of nanocrystalline silica (NCS), i.e., particles below 100 nm. We present a methodology to quantify the crystalline silica content in the sub-100 nm size fraction of the aerosol released during engineered stone fabrication using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Aerosol was generated in a test chamber designed per EN 1093-3 and sampled using cascade impactors. XRD and FTIR analysis showed the presence of both a-quartz (15-60%) and cristobalite (10-50%) polymorphs in all size fractions. With increasing particle size, the cristobalite content increased. Seventy percent of the total aerosol mass in the sub-100 nm fraction was found to be crystalline silica, qualitatively confirmed by electron diffraction and electron energy loss spectroscopy. The presence of other minerals was detected in all size fractions; no polymeric resin binder was detected in the sub-100 nm fraction. Although the sub-100 nm fraction was about 1% of the aerosol mass, it accounted for 4-24% of the aerosol surface area based on the total lung deposition. If the surface area is a more relevant exposure metric, the assessment of the efficacy of current engineering control systems using mass as an exposure metric may not provide adequate protection. [Description provided by NIOSH]
• Subjects:
  Aerosols Occupational Health Particulate Matter Respiratory System Safety Silicon Dioxide
• Keywords:
  Aerosol Particles Crystalline Silica Inhalation Studies Nanocrystals Nanoparticles Particle Size Stone Products
• ISSN:
  2470-1343
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Chicago Region [OSHA] ; Ohio
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; DFSE - Division of Field Studies and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  9
• Issue:
  51
• NIOSHTIC Number:
  nn:20070423
• Citation:
  ACS Omega 2024 Dec; 9(51):50308-50317
• Contact Point Address:
  Bon Ki Ku, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH) Centers for Disease Control and Prevention (CDC), 1090 Tusculum Ave, Cincinnati, Ohio 45226, United States
• Email:
  bku@cdc.gov
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2025
• NORA Priority Area:
  Construction ; Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  ACS Omega
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:d40bd859f99fc97ad2de75e9326b906658f912e19eddead8d6fa0d41c5b1c43a25b8c787e3f6c6077b6c6ce63deb46321d8485e3f1f71e1ab4954978c62d0077
• Download URL:
  https://stacks.cdc.gov/view/cdc/208643/cdc_208643_DS1.pdf
• File Type:
  [PDF - 5.71 MB ]