Size distribution and estimated respiratory deposition of total chromium, hexavalent chromium, manganese and nickel in gas metal arc welding fume aerosols

Details

• Personal Author:
  Cena L ; Chen B ; Cumpston A ; Keane M
• Description:
  Objective: Assess the particle size distribution from 10 nm to >30 um of total Cr, Cr(VI), Mn and Ni in welding fumes generated by GMAW of mild and stainless steel, establish the fraction of Cr(VI) in total Cr for each particle size range, and provide an understanding of the regional deposition of these metals in the human respiratory system. Methods: Welding fumes were generated with a robotic welder operating in axial spray mode. Samples were collected using a nano multiple orifice uniform deposition impactor with polyvinyl chloride filters on each stage. The filters were analyzed by inductively coupled plasma mass spectrometry and ion chromatography. Limits of detection and quantitation were experimentally calculated and percent recoveries were measured from metal spikes. The fraction of Cr(VI) in total Cr was assessed by calculating the ratio of Cr(VI) to total Cr mass for each particle size range. Regional deposition of each metal was estimated according to respiratory-deposition models. Results: The weight percent (wt%; +/- standard deviation) of Mn in mild steel fumes was 9.2% (+/-6.8%). For stainless steel fumes, the wt%s were 8.4% (+/-5.4%) for total Cr, 12.2% (+/-6.5%) for Mn, 2.1% (+/-1.5%) for Ni and 0.5% (+/-0.4%) for Cr(VI). All metals presented a submicron fraction between 0.04 and 0.6 um. Total Cr and Ni presented an additional fraction <0.03um. On average 6% of the Cr was found in the Cr(VI) valence state. There was no statistical difference between the smallest and largest mean Cr(VI) to total Cr mass ratio (p-value=0.19), hence particle size did not affect the contribution of Cr(VI) relative to total Cr. The predicted total respiratory deposition for the metal particles was -20%. The sites of principal deposition were the head airways (7-10%) and the alveolar region (8-9%). Estimated Cr(VI) deposition was highest in the alveolar region (8.8%). Conclusions: Total fume mass obtained from gravimetric analysis of the impactor stages presented a tri-modal distribution with a substantial contribution of particles in the 0.006-0.06 um range. Chemical analyses of the individual metals did not reveal as prominent mass in this smaller size range. The discrepancy may be due to the lesser reliability of gravimetric analysis compared to chemical analysis. The wt% of metals in the fumes differed from that of the consumables. Future research should focus on other welding processes such as SMAW, FCAW and gas tungsten arc welding. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollutants, Occupational Dust Lung Manganese Men Metals Nickel Occupational Health Particulate Matter Respiratory System Safety Welding Women

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• Keywords:
  Aerosol-particles Filters Fumes Gravimetric-analysis Humans Manganese-compounds Metal-compounds Metal-dusts Metal-fumes Metallic-compounds Metallic-dusts Metallic-fumes Nanotechnology Nickel-compounds Particulates Pulmonary-system Respirable-dust Sampling

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• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; OSHA Region 8 ; Utah ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  72-73
• NIOSHTIC Number:
  nn:20046279
• Citation:
  AIHce 2015: American Industrial Hygiene Conference and Exposition, May 30 - June 4, 2015, Salt Lake City, Utah. Falls Church, VA: American Industrial Hygiene Association, 2015 May; :72-73
• CAS Registry Number:
  Chromium (CAS RN 7440-47-3) ; Chromium(6+) (CAS RN 18540-29-9) ; Manganese (CAS RN 7439-96-5) ; Nickel (CAS RN 7440-02-0)
• Federal Fiscal Year:
  2015
• NORA Priority Area:
  Construction
• Peer Reviewed:
  False
• Source Full Name:
  AIHce 2015: American Industrial Hygiene Conference and Exposition, May 30 - June 4, 2015, Salt Lake City, Utah
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:8dd45cd7075f32258a1bff536650e3254dbcaeebaf5d3801fb4baffd6fdd834840efd3d30a0bbd37b5c47b605f5ddbb681061000b2886a6e2dcb791fffeae28d
• Download URL:
  https://stacks.cdc.gov/view/cdc/201383/cdc_201383_DS1.pdf
• File Type:
  [PDF - 691.31 KB ]