Airborne fiber concentration and size distribution of mineral fibers in area with serpentinite outcrops in Aichi prefecture, Japan

Our plain-English summary of Airborne fiber concentration and size distribution of mineral fibers in area with serpentinite outcrops in Aichi prefecture, Japan, by K. Sakai, N. Hisanaga, N. Kohyama, et al (Industrial Health, 2001).

The study

• Authors: K. Sakai, N. Hisanaga, N. Kohyama, E. Shibata, Y. Takeuchi
• Journal: Industrial Health
• Published: 2001;39(2):132-40
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Airborne fiber concentrations and size distributions of both asbestos and nonasbestos fibers were determined at property boundaries of 4 serpentinite quarries producing crushed stone (quarry property boundary), 10 sites within 10 km of the area with serpentinite outcrops (serpentinite area), and 2 sites in a reference area. The asbestos was identified in 7 rock and 3 soil samples collected in the serpentinite area. The geometric means of airborne concentrations of asbestos and nonasbestos fibers longer than 0.2 microm in length were: 384 and 447 fibers/liter (f/L) in the quarry property boundary (in operation), 12 and 124 f/L in the quarry property boundary (in closed), 5 and 103 fibers/liter in the serpentinite area, and less than 2 and 59 fibers/liter in the reference area, respectively. There was a significant difference in airborne concentrations of both asbestos and nonasbestos fibers among the areas. Ttremolite/actinolite were found with chrysotile in the stones. Airborne concentrations of tremolite/actinolite were higher than those of chrysotile at the quarry property boundary and in the serpentinite area. Tremolite/actinolite were also found in the soils. There was no significant difference among the areas in the arithmetic means of fiber size distribution of both asbestos and nonasbestos fibers.

In plain English

This study measured mineral fibers in outdoor air around serpentinite rock outcrops in eastern Aichi Prefecture, Japan. In 1996 the authors took one two-hour air sample at each of 16 sites. Four were at boundaries of serpentinite quarries producing crushed stone (2 operating, 2 closed), 10 within 10 km of the outcrops, and 2 in a reference area. Fibers were counted by electron microscopy. The authors also tested 7 rock and 3 soil samples. Tremolite/actinolite was found in all, and chrysotile in 2 rock samples. The geometric mean of airborne asbestos fibers longer than 0.2 µm was 384 fibers per liter at operating quarry boundaries, 12 at closed quarry boundaries, 5 in the serpentinite area and less than 2 in the reference area. This difference was statistically significant. Tremolite/actinolite exceeded chrysotile in most samples from quarry boundaries and the serpentinite area. Fiber sizes did not differ significantly between areas. The authors concluded that asbestos levels inside the quarries would be very high and quarry workers greatly exposed. Levels in the surrounding serpentinite area were similar to urban areas.

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: Environmental measurement survey: outdoor air sampling and rock and soil (bulk) sampling, with fibers analysed by analytical transmission electron microscopy
• Who was studied: 16 outdoor air sampling sites in the Shinshiro area of eastern Aichi Prefecture, Japan, sampled March to May 1996: boundaries of 4 serpentinite quarries (2 operating, 2 closed), 10 sites within 10 km of serpentinite outcrops, and 2 reference sites in Tsukude Village about 20 km away. Also 7 stone and 3 soil samples.
• Exposure: Airborne asbestos (chrysotile and tremolite/actinolite) and nonasbestos mineral fibers longer than 0.2 µm, released from serpentinite rock, crushed-stone quarrying and soil
• Main results:
  • Soil samples: tremolite/actinolite was found in all 3; chrysotile was found in none
  • Geometric mean airborne asbestos (fibers longer than 0.2 µm): 384 f/L at operating quarry boundaries, 12 f/L at closed quarry boundaries, 5 f/L in the serpentinite area, and less than 2 f/L in the reference area
  • Airborne asbestos concentrations differed significantly among the areas (p=0.034)
  • Geometric mean airborne nonasbestos fibers: 447 f/L at operating quarry boundaries, 124 f/L at closed quarry boundaries, 103 f/L in the serpentinite area, and 59 f/L in the reference area (significant difference, p=0.036)
  • Tremolite/actinolite concentrations were higher than chrysotile in most air samples from the quarry boundaries and the serpentinite area
  • Asbestos as a share of all mineral fibers in air: 47% (42–51) at operating quarry boundaries, 9% (8–10) at closed quarry boundaries, 9% (0–26) in the serpentinite area, 0% in the reference area
  • Asbestos fiber sizes did not differ significantly among the areas
  • Across all air samples, the mean length of chrysotile (1.2 µm) was significantly shorter than that of tremolite/actinolite (3.2 µm)
  • No fibers of the size that animal experiments linked most strongly to mesothelioma (longer than 8 µm and 0.25 µm or less in diameter) were found in any air sample
• The authors' conclusion: The authors concluded that airborne asbestos inside the serpentinite quarries would be very high and that quarry workers would be greatly exposed. Concentrations in the surrounding serpentinite area were similar to those in urban areas. They also wrote that serpentinite appears to be a source of fibrous magnesium and aluminum silicates as well as asbestos.
• Limitations the authors state:
  • Tremolite and actinolite could not be told apart by the analysis and were counted together as one group
  • The mineral type of the nonasbestos fibers was not identified
  • No statistical comparison among areas was done for chrysotile alone, because detection limits at the operating quarries differed too much from the other sites

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Mineral Fiber, Serpentinite, Actinolite, Chrysotile, Tremolite.

Related studies

• Airborne brake wear debris: size distributions, composition, and a comparison of dynamometer and vehicle tests — P.G. Sanders, N. Xu, et al. (2003)
• A study of the size distributions of airborne amosite fibres in the manufacture of asbestos insulation boards — S.T. Beckett, J.L. Jarvis (1979)
• Comparison of direct and indirect methods of measuring airborne chrysotile fibre concentration — C. Eypert-Blaison, S. Veissiere, et al. (2010)
• Monitoring of airborne asbestos fibers in an urban ambient air of Shahryar City, Iran: levels, spatial distribution, seasonal variations, and health risk assessment — F. Taghizadeh, A.J. Jafari, et al. (2019)
• Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity — G. Boulanger, P. Andujar, et al. (2014)
• Asbestos fiber concentration in the area surrounding a former asbestos cement plant and excess mesothelioma deaths in residents — S. Kumagai, N. Kurumatani (2009)

Browse more research in Industrial Health, or return to medical research.