The organic content of international reference samples of asbestos

Our plain-English summary of The organic content of international reference samples of asbestos, by J. Hilborn, R.S. Thomas, R.C. Lao (The Science of the Total Environment, 1974).

The study

• Authors: J. Hilborn, R.S. Thomas, R.C. Lao
• Journal: The Science of the Total Environment
• Published: 1974;3(2):129-40
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This laboratory chemical analysis examined the oily organic material on five reference asbestos samples supplied by the Union International Contre le Cancer (U.I.C.C.): anthophyllite, amosite, Rhodesian chrysotile ("Chrysotile A"), crocidolite and Canadian chrysotile ("Chrysotile B"). The authors extracted 30 to 60 gram samples with the solvent pentane. They examined the extracts by gas chromatography, mass spectrometry, and ultraviolet and fluorescence spectroscopy. Oil made up between 0.020% (Chrysotile A) and 0.033% (amosite) of the samples. The authors suggested that storing the asbestos in polyethylene bags may have contaminated the samples. More than sixty components were seen in each extract, and the main components appeared to be n-alkanes. Some peaks matched the timing of polycyclic aromatic hydrocarbons, including benzo[a]pyrene, but this identification was uncertain. A further test of the anthophyllite oil showed no sign of benzo[a]pyrene or benzo[k]fluoranthene. The authors concluded that the organic content consisted largely of n-alkanes. They found the evidence for potentially carcinogenic polycyclic hydrocarbons inconclusive. Such compounds, if present, would occur only as traces, and the complex chromatograms made identification uncertain.

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 chemical analysis: solvent (pentane) extraction of asbestos samples, analysed by gas chromatography, mass spectrometry, ultraviolet and fluorescence spectroscopy
• Who was studied: five U.I.C.C. reference standard asbestos samples; 30 to 60 g of each was extracted (no people or animals studied)
• Exposure: U.I.C.C. anthophyllite, amosite, Chrysotile "A" (Rhodesian chrysotile), crocidolite and Chrysotile "B" (Canadian chrysotile)
• Main results:
  • Pentane-extractable oil content was 0.032% for Chrysotile "B", 0.033% for amosite, 0.023% for crocidolite, 0.020% for Chrysotile "A" and 0.021% for anthophyllite. Amosite and Chrysotile "B" yielded about 50% more oil than the other three.
  • More than sixty components were observed in each of the five extracts, and n-alkanes appeared to be the major components
  • Peaks matching the retention times of some polycyclic aromatic hydrocarbons (including naphthalene, phenanthrene, pyrene, chrysene, BkF and BaP) were seen. Most of these were minor peaks, and their identity was equivocal.
  • The anthophyllite oil differed from the other four: most of it was lower-molecular-weight hydrocarbons
  • Fluorescence emission maxima did not correspond to benzo[k]fluoranthene (BkF). After column chromatography, there was no indication of BaP or BkF in the anthophyllite oil.
  • There appeared to be no correlation between oil color and absorbance at 421 nm. Chrysotile "A" had the lowest oil yield but the strongest absorbance (0.361).
• The authors' conclusion: The authors concluded that the organic content of the U.I.C.C. reference samples consists largely of n-alkanes. They found the evidence for potentially carcinogenic polycyclic hydrocarbons inconclusive for two reasons: such compounds, if present, occur only as traces, and the complex chromatograms made identification by retention times alone uncertain.
• Limitations the authors state:
  • The high oil yields may partly reflect contamination from storing the asbestos in polyethylene bags, or the low-temperature extraction method
  • Polycyclic aromatic hydrocarbons were identified only by matching peaks to added standards, which was uncertain in complex chromatograms
  • The ultraviolet spectra came from mixtures and must be interpreted with caution

Related studies

• UICC standard reference samples of asbestos — V. Timbrell, J.C. Gibson, et al. (1968)
• Further observations on the short-term retention and clearance of asbestos by rats, using UICC reference samples — A.P. Middleton, S.T. Beckett, et al. (1979)
• A simple dispenser for generating dust clouds from standard reference samples of asbestos — V. Timbrell, A.W. Hyett, et al. (1968)
• Development of the Regular Interlaboratory Counting Exchanges (RICE) scheme to include visual reference counts and samples from asbestos clearance operations — P.W. Brown, N.P. Crawford, et al. (1994)
• New Insights on Diagnostic Reproducibility of Biphasic Mesotheliomas: A Multi-Institutional Evaluation by the International Mesothelioma Panel From the MESOPATH Reference Center — F. Galateau Salle, N. Le Stang, et al. (2018)
• The differential diagnosis between pleural sarcomatoid mesothelioma and spindle cell/pleomorphic (sarcomatoid) carcinomas of the lung: evidence-based guidelines from the International Mesothelioma Panel and the MESOPATH National Reference Center — A.M. Marchevsky, N. LeStang, et al. (2017)

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