Inhalation Exposure to Wood Sealant with Nano-Zinc Oxide Elicits Minimal Pulmonary Inflammation in Rats

Details

• Personal Author:
  Burrelli L ; Cooper M ; Erdely A ; Falcone L ; Julie GA ; Kodali VK ; Lippy B ; McKinney W ; Roberts, Jennifer R. ; Salmen R ; West, Gavin H. ; Zeidler-Erdely PC
• Description:
  Background and Purpose: Increased use of engineered nanomaterials in construction and manufacturing adds new attributes to products and improves quality. New wood coating sealant products, used in spraying operations, that contain zinc oxide nanoparticles (nano-ZnO) help protect natural wood from UV-light-degradation and weathering. Therefore, a potential for inhalation exposure to nano-ZnO containing aerosols exists for workers and consumers. The objective of this study was to investigate the pulmonary responses to nano-ZnO-containing wood spray sealant in vivo. Methods: First, we sought to investigate the nanomaterials released during construction operations and performed real-time worker measurements of aerosol and particulates as previously measured by CPWR collaborators. After spraying operations, the respirable particles in the personal breathing zone were measured at 20.00 +/- 3.52 mg/m3 and contained 0.49 +/- 0.09 mg/m3 of zinc. Based off these measurements, Sprague Dawley rats (200 g) were exposed to respirable ZnO-containing wood spray sealant (total sealant aerosol 20 mg/m3 14 ppm ammonia and propylene glycol) or filtered air (sham-control) for 4 hours per day for 1 and 14 days. Post-exposure time points assessed pulmonary toxicity at 1 day, 1 week, 1 month, and 3 months after the last exposure day. Bronchoalveolar lavage fluid (BALF) and lungs were collected at the time of sacrifice and assessed for lung inflammation (polymorphonuclear leukocytes [PMN] influx), lactate dehydrogenase activity levels (i.e. lung cytotoxicity), and histopathology. Lung associated lymph nodes and spleens were also collected to evaluate lymphocyte profiles, as zinc is a known immunotoxicant. Results: Rat weights between nano-ZnO exposed and sham-control were not different between either exposure at any of the different exposure durations or post-exposure time points. At all timepoints post-exposure, no significant differences in lung inflammation or cytotoxicity were found compared to sham-control, which indicates a lack of a pulmonary response. In addition, lung histopathological analyses indicated no differences between sham-control and nano-ZnO exposed rats at any post-exposure timepoint. Lymphocyte profiles in lymph nodes and spleen also did not differ. Conclusions: These results indicate that the wood spray sealant, which contained nano-ZnO, did not induce pulmonary inflammation after inhalation exposure at the concentrations tested in this study. [Description provided by NIOSH]
• Subjects:
  Construction Industry Dust Lung Occupational Health Particulate Matter Respiratory System Safety Wood
• Keywords:
  Construction Industry Inhalation Nanoparticles Particulates Pulmonary Effects Sealants Wood Dusts Zinc Oxide
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Maryland ; OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  198
• NIOSHTIC Number:
  nn:20069342
• Citation:
  Toxicologist 2024 Mar; 198(S1):317
• CAS Registry Number:
  Zinc oxide (ZnO) (CAS RN 1314-13-2)
• Federal Fiscal Year:
  2024
• NORA Priority Area:
  Construction
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 63rd Annual Meeting & ToxExpo, March 10-14, 2024, Salt Lake City, Utah
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:2b6c26ac05b1aee4ffa00c7cb6ab5e5e04dde3c258819eef27d7a20d195bc891707db56e46d94450018e8b8a0d4dcdf53b481b9e436d8f1b4039ba2ad9b30803
• Download URL:
  https://stacks.cdc.gov/view/cdc/207840/cdc_207840_DS1.pdf
• File Type:
  [PDF - 558.99 KB ]