Chrysotile in water

Our plain-English summary of Chrysotile in water, by S. Speil (Environmental Health Perspectives, 1974).

The study

• Author: S. Speil
• Journal: Environmental Health Perspectives
• Published: 1974;9:161-3
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The problems of quantitating chrysotile in water by fiber count techniques are reviewed briefly and the use of mass quantitation is suggested as a preferable measure. Chrysotile fiber has been found in almost every sample of natural water examined, but generally transmission electron miscroscopy (TEM) is required because of the small diameters involved. The extreme extrapolation required in mathematically converting a few fibers or fiber fragments under the TEM to the fiber content of a liquid sample casts considerable doubt on the validity of numbers used to compare chrysotile contents of different liquids.

In plain English

This brief paper, from the Johns-Manville Research and Development Center in Denver, reviewed problems with measuring chrysotile in water by counting fibers. It described the laboratory's alternative, which measures fiber mass by transmission electron microscopy. The author reported that every natural water sample examined contained some chrysotile. In the water supplies of ten cities, chrysotile ranged from 0.005 to 6.0 micrograms per gallon, and all the chrysotile seen was submicron in size. Monthly sampling for one year found no statistically significant difference in the yearly average between two rivers. The Connecticut River starts in a serpentine belt; the Juniata River flows through an area without serpentine rocks. Amphibole was not measured. Among 30 beer brands, the beer with the most chrysotile had never been filtered through a chrysotile-containing pad. The author noted that results can vary two- to threefold between operators and five- to tenfold between laboratories. One common counting method multiplies about 20 observed fibers by 250,000. The author concluded that everyone is exposed to some "relatively insignificant" amount of chrysotile in drinking water, and expressed reservations about fiber-count data.

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: Brief methodological review and commentary, reporting descriptive measurements from the author's laboratory (Johns-Manville Research and Development Center)
• Who was studied: Water samples examined by the laboratory, United States: potable water supplies of ten cities; the Connecticut River and the Juniata River, sampled at monthly intervals for about one year; and 30 brands of beer
• Exposure: Chrysotile fibers in drinking water, river water and beer, measured as mass (micrograms per gallon) after filtering, ashing at 800°F and transmission electron microscopy; amphibole was not measured in the river study
• Main results:
  • Every sample of natural water examined contained some small amount of chrysotile
  • In the water supplies of ten cities, chrysotile content ranged from 0.005 to 6.0 micrograms per gallon
  • In river waters, chrysotile made up from 0.001% to possibly 0.5% of the filtered residue by weight
  • No chrysotile in potable water samples could be identified by optical microscopy alone; all chrysotile fiber observed was submicron in size
  • After one year of monthly sampling, there was no statistically significant difference in the yearly average amount of fiber between the Connecticut River and the Juniata River, although month-to-month and place-to-place variation was large
  • Average chrysotile in potable water was about 1 microgram per gallon. Assuming 2 liters a day over a 70-year lifetime (50,000 liters), the author calculated a lifetime consumption of 0.05 g, or 0.3 g at the maximum of 6 micrograms per gallon
  • Of 30 beer brands evaluated, the beer with the most chrysotile had never been filtered through a chrysotile-containing pad; it was made from spring water from serpentine mountains in Pennsylvania
  • In one common fiber-count method, a count of 5 x 10^6 fibers per liter rests on about 20 fibers seen in about 160 to 200 electron microscope fields, multiplied by 250,000; the author expressed reservation about the validity of such quantitative data
• The authors' conclusion: The author concluded that everybody is exposed to some, relatively insignificant, amount of chrysotile fiber in drinking water. The author also suggested mass quantitation as preferable to fiber counts.
• Limitations the authors state:
  • Results varied two- to threefold between operators or replicate examinations, and five- to tenfold between laboratories
  • The ashing and rub-out technique does not preserve fibers in their original form, so fiber numbers cannot be reported by this method
  • The river study measured only chrysotile and did not measure amphibole fiber

Topics

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

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• Chemical contamination of California drinking water — H.H. Russell, R.J. Jackson, et al. (1987)
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• Asbestos fibres in beverages and drinking water — H.M. Cunningham, R. Pontefract (1971)

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