Occupational exposure to mineral fibres: analysis of results stored on colchic database

Our plain-English summary of Occupational exposure to mineral fibres: analysis of results stored on colchic database, by E. Kauffer, R. Vincent (The Annals of Occupational Hygiene, 2007).

The study

• Authors: E. Kauffer, R. Vincent
• Journal: The Annals of Occupational Hygiene
• Published: 2007;51(2):131-42
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The aim of this paper is to present fibre exposure data recorded on the COLCHIC database. This database consolidates all occupational exposure data collected in French companies by the Caisses Régionales d'Assurance Maladie (regional health insurance funds, CRAM) and the Institut National de Recherche et de Sécurité (national institute for research and safety, INRS). A total of 8029 concentration results, expressed in number of fibres measured by phase-contrast optical microscopy, are available for exposure to asbestos fibres, ceramic fibres and man-made mineral fibres other than ceramic fibres. Presentation of base data by activity branch, activity sector or workplace permits identification of situations, for which prevention efforts are most essential. Analysis of exposure levels during the 1986-2004 period show that these are broadly influenced by changes in the exposure limit values. Wearing of respiratory protection equipment by employees is also discussed. The data may be helpful to occupational physicians performing occupational screening of exposed workers and to epidemiologists seeking information for building job-exposures matrices. In this respect, a database (FIBREX) will be available on the INRS web site (www.inrs.fr) at the beginning of 2007. This database will provide a higher level of detail in activity and workplace description than that which was possible for practical reasons in this paper.

In plain English

This paper described fibre measurements stored in COLCHIC, a French database of workplace air samples. The samples were taken in companies by regional health insurance fund laboratories and by the national institute INRS. Of 9282 fibre results from 1986 to 2004, the authors analysed 8029 that the sampling technician had classed as asbestos (fibre types not specified), ceramic fibres, or other man-made mineral fibres. The microscope method used cannot itself identify fibre type. The data were split at the start of 1997, when current French limit values took effect. Mean asbestos concentration in personal samples fell from 2.5 fibres/ml (1986–1996) to 0.60 fibres/ml (1997–2004), the largest drop of the three fibre categories. In 1997–2004, measured asbestos levels averaged 0.86 fibres/ml where workers wore effective respiratory protection and 0.071 fibres/ml where they did not. After 1997, most asbestos sampling was in the construction sector, which also had the most results above 0.1 fibre/ml (96 of 239). The authors concluded that exposure levels were broadly influenced by changes in limit values. They cautioned that results above those values cannot simply be read as limit breaches, and that the data are less accurate than specialised studies.

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: Descriptive analysis of workplace air-sampling results stored in a national occupational exposure database (COLCHIC)
• Who was studied: Workplace air samples taken in French companies by the regional health insurance fund (CRAM) laboratories and INRS, 1986–2004. Of 9282 fibre results, 8029 (86.5%) involved asbestos, ceramic fibres or man-made mineral fibres excluding ceramic fibres. These comprised 4244 asbestos, 1852 ceramic and 1933 man-made mineral fibre results, from personal and static samples.
• Exposure: Airborne fibre concentrations (fibres/ml) counted by phase-contrast optical microscopy. Fibres were grouped as asbestos (fibre type not specified), ceramic fibres, and man-made mineral fibres other than ceramic (slag, rock, glass, oxide glass). Fibre type was assigned by the sampling technician, not by the microscope. Results were reported by activity branch, activity sector and workplace, for 1986–1996 and 1997–2004.
• Main results:
  • Asbestos, personal sampling: mean concentration fell from 2.5 fibres/ml (1986–1996) to 0.60 fibres/ml (1997–2004). This was the greatest reduction among the three fibre categories. Static asbestos samples fell from 1.9 to 0.16 fibres/ml (Table 4).
  • Ceramic fibres, personal sampling: mean concentration went from 1.7 to 1.1 fibres/ml. Man-made mineral fibres, personal sampling: mean went from 0.54 to 0.38 fibres/ml (Table 4). Mean concentrations in static samples were lower than in personal samples.
  • Asbestos, 1997–2004, personal samples: mean measured concentration was 0.862 fibres/ml (0.86 in Table 5, N=398) when the operator wore effective respiratory protective equipment, and 0.071 fibres/ml (N=142) when the operator did not. In 1986–1996 the figures were 5.0 (N=407) and 0.76 fibres/ml (N=518).
  • From 1997, most asbestos sampling was in the construction sector. This sector also had the greatest number of asbestos results above 0.1 fibre/ml: 96 of 239 results in Table 10.
  • The workplaces where the 0.1 fibre/ml asbestos value was most often exceeded were machining stations (including confinement and removal activities), building finishing and cleaning, and repair and maintenance work.
• The authors' conclusion: The authors concluded that measured exposure levels were broadly influenced by changes in exposure limit values. They found that wearing of respiratory protective equipment depended strongly on the measured exposure level, and stated that this must be taken into account when estimating inhaled dose in epidemiological studies.
• Limitations the authors state:
  • Because COLCHIC is a general database, the authors stated its information cannot be as accurate as that in specialised studies.
  • Results above limit values cannot simply be read as limit-value breaches. Sampling durations were not necessarily representative of the reference period (1 h for asbestos, 8 h for other fibres), and respiratory protection must be taken into account.
  • Phase-contrast optical microscopy cannot identify fibre type, so fibre type relied on the sampling technician's information. The authors nonetheless judged this classification reliable, based on fibre-width data.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Respirator.

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