Changes in concentrations and characteristics of asbestos fibers dispersed from corrugated asbestos cement sheets due to stabilizer treatment

Our plain-English summary of Changes in concentrations and characteristics of asbestos fibers dispersed from corrugated asbestos cement sheets due to stabilizer treatment, by H.S. Jung, J. Jang, E.K. Park, et al (Journal of Environmental Management, 2021).

The study

• Authors: H.S. Jung, J. Jang, E.K. Park, Y. Cho, J.C. Lee, H. Kim
• Journal: Journal of Environmental Management
• Published: 2021;285:112110
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos management in Korea has, to date, focused exclusively on dismantlement and removal; however, the effective management of asbestos in public facilities and rural dwellings is also critical. This study compares eight different asbestos stabilization treatments and their effectiveness in reducing asbestos fiber dispersion from weathered corrugated asbestos cement sheets (CACS) under different wind conditions. The effectiveness of the different asbestos stabilizers was assessed in order to identify the characteristics of fibers dispersed from treated CACS samples. The impact of wind speed on the concentration and composition of the dispersed fibers was also evaluated. For all wind speeds, the concentration of the fibers dispersed from the CACS samples that were treated with stabilizers decreased relative to the untreated CACS. These results show that asbestos concentrations were considerably reduced following stabilizer treatment and that treated CACS dispersed fewer asbestos fibers relative to untreated CACS. The results of this study will be useful for the development of strategies regarding the appropriate management of asbestos in public buildings.

Copyright © 2021 Elsevier Ltd. All rights reserved.

In plain English

This was a laboratory experiment in Korea on weathered corrugated asbestos cement sheets (CACS), a roofing material. The authors took sheets that had been in place for more than ten years from sites in Seoul and cut them into 200 by 200 mm pieces. They coated some pieces with one of eight commercial asbestos stabilizers: inorganic products from Korea, Australia and Japan, and four organic/synthetic products from Japan. Pieces were blown at 5 and 10 m/s in an air erosion device, and airborne fibers were measured by microscopy. At 5 m/s, untreated pieces released a mean of 0.2221 fiber/cc versus 0.0064 fiber/cc for treated pieces. At 10 m/s the figures were 0.3386 versus 0.0121 fiber/cc. Across the two wind speeds, treatment lowered concentrations by 96.4–97.1%. Fiber concentrations did not differ significantly between inorganic and organic/synthetic stabilizers. The released fibers were chrysotile. Untreated pieces released more fibers. At 10 m/s, fibers from both treated groups were significantly shorter; at 5 m/s, only those from inorganic-treated pieces were. The authors concluded that stabilizers were highly effective at reducing fiber dispersion. The article's text and tables disagree on some fiber-length details.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: laboratory air erosion (wind) experiment comparing untreated and stabilizer-treated asbestos cement sheet specimens
• Who was studied: Corrugated asbestos cement sheets in place for more than ten years, obtained from reconstruction and deconstruction sites in Seoul, Korea. The pieces were cut to 200 by 200 mm. The tables list 6 untreated and 24 treated measurements.
• Exposure: Wind speeds of 5 and 10 m/s applied to untreated specimens and to specimens coated with one of eight commercial asbestos stabilizers (inorganic from Korea, Australia and Japan; four organic/synthetic from Japan). Air was sampled at 10 L/min for 1 hour. Fibers were counted by phase-contrast microscopy and characterized by transmission electron microscopy. The dispersed fibers were chrysotile.
• Main results:
  • Fiber concentrations from treated sheets were 96.4–97.1% lower than from untreated sheets. This range covers both wind speeds (5 and 10 m/s) together.
  • At 5 m/s: untreated sheets (N = 6) released 0.2221 plus or minus 0.0175 fiber/cc, and treated sheets (N = 24) released 0.0064 plus or minus 0.0032 fiber/cc (p less than 0.0001).
  • At 10 m/s: untreated sheets released 0.3386 plus or minus 0.0189 fiber/cc, and treated sheets released 0.0121 plus or minus 0.0066 fiber/cc (p less than 0.0001). Fiber concentration from untreated sheets rose with wind speed.
  • Fiber concentrations (measured by phase-contrast microscopy) did not differ significantly between sheets treated with inorganic stabilizers and sheets treated with organic/synthetic stabilizers.
  • In the regression analysis, wind speed and stabilizer treatment were the main factors affecting fiber concentration. The adjusted R2 was 0.6611, which the authors described as a reliability of 66.1%.
  • At 5 m/s, 73.6% of the chrysotile fibers from untreated sheets were 2–10 μm long.
  • At 5 m/s, the geometric mean chrysotile fiber lengths were 5.63 μm for untreated sheets (663 fibers), 2.69 μm for inorganic-treated sheets (11 fibers) and 8.99 μm for organic-treated sheets (6 fibers). The statistical grouping placed the organic-treated sheets with the untreated sheets and the inorganic-treated sheets apart from both.
  • At 10 m/s, the geometric mean chrysotile fiber lengths were 8.95 μm for untreated sheets (1468 fibers), 3.16 μm for inorganic-treated sheets (165 fibers) and 3.8 μm for organic-treated sheets (17 fibers). Both treated groups differed from the untreated group.
  • The authors reported that untreated sheets dispersed more and longer chrysotile fibers than stabilizer-treated sheets.
• The authors' conclusion: The authors concluded that using stabilizers on asbestos-containing CACS is highly effective in decreasing asbestos fiber dispersion. They also concluded that stabilizers can be used to extend the lifespan of aging CACS roofing in Korea.
• Limitations the authors state:
  • The chemical compositions of the stabilizers tested were unknown because they are proprietary.
  • Results could not be directly compared with earlier studies because the total sampling flow rate differed between studies.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement.

Related studies

• Mobilization of asbestos fibers by weathering of a corrugated asbestos cement roof — T. Ervik, S. Eriksen Hammer, et al. (2021)
• Emission of airborne fibers from mechanically impacted asbestos-cement sheets and concentration of fibrous aerosol in the home environment in Upper Silesia, Poland — J.S. Pastuszka (2009)
• Evaluating the efficiency of an asbestos stabilizer on ceiling tiles and the characteristics of the released asbestos fibers — H.S. Jung, J.S. Cha, et al. (2015)
• Characteristics of asbestos fibers in lung tissue from occupational and environmental asbestos exposure of lung cancer patients in Busan, Korea — H.S. Jung, E.K. Park, et al. (2020)
• Asbestos Exposure Level and the Carcinogenic Risk Due to Corrugated Asbestos-Cement Slate Roofs in Korea — E.S. Lee, Y.K. Kim (2021)
• Respirable inorganic fibers dispersed in air and settled in human lung samples: Assessment of their nature, source, and concentration in a NW Italy large city — S. Capella, D. Bellis, et al. (2020)

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