Characterization of Microplastics in Sediment Using Stereomicroscopy and Laser Direct Infrared (LDIR) Spectroscopy

Details

• Personal Author:
  Cali S ; Chen HY ; Cheng Y-L ; Li A ; Tisinger L ; Yu Z ; Zhang R
• Description:
  The analysis of microplastics (MP) becomes more difficult for smaller sizes, especially in complex matrices such as sediment of natural waters. In this work, we analyzed MPs in sediment using laser direct infrared (LDIR) imaging, a relatively new technique in environmental MP studies. Sediment samples were spiked with analytical surrogates (polyethylene spheres), and subjected to density separation, wet peroxide oxidation, calcite removal, and filtration. The extracted particles were coated on to a low-emissivity glass slide which was first examined on a stereomicroscope. Six slides (two sediment samples and four different blanks) were further analyzed using an Agilent LDIR system. Approximately 520 and 430 MP/g were found in the two samples, with diameter ranging 20-3384 µm and 84% being smaller than 100 µm. The increase in particle count with decreasing particle sizes followed a power law curve, suggesting that a large portion of the smaller MPs was generated by the breakdown of larger plastic pieces. Major polymers found in this work included polyamide, polyester, polytetrafluoroethylene, and polyacetal. Most MPs were fragments, while beads and fiber were also found. In the two sediment samples, 14% and 46% of the total particles, respectively, were composed of non-plastic micro-sized particles, including natural polyamide, cellulose, chitin, rubber, and "unknown". Challenges, potential biases, and uncertainties are discussed. This work is the first application of LDIR imaging on MPs in natural sediment. [Description provided by NIOSH]
• Subjects:
  Environmental Pollution Microbiology Occupational Health Plastics Polymers Safety
• Keywords:
  Author Keywords: Lake Michigan Environmental Contamination Infrared Spectroscopy Laser Direct Infrared (LDIR) Spectroscopy Lasers Microplastics Microscopic Analysis Particle Size Analysis Plastic Products Sediment
• ISSN:
  1342-937X
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Illinois ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  22-30
• Volume:
  108
• NIOSHTIC Number:
  nn:20068008
• Citation:
  Gondwana Res 2022 Aug; 108:22-30
• Email:
  anli@uic.edu
• Federal Fiscal Year:
  2022
• Performing Organization:
  University of Illinois at Chicago
• Peer Reviewed:
  True
• Start Date:
  20050701
• End Date:
  20290630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:d9af18309d0405b7ab9fb079217d6b621882d47712cf531fae73abe97351f1bd1e8b3c3de2f10d0cb31816982f47738c814aebec92f3787e2e999898cedd1c54
• Download URL:
  https://stacks.cdc.gov/view/cdc/230239/cdc_230239_DS1.pdf
• File Type:
  [PDF - 2.83 MB ]