Asbestos distribution in the Central Serpentine District of Maryland-Pennsylvania

Our plain-English summary of Asbestos distribution in the Central Serpentine District of Maryland-Pennsylvania, by J.H. Puffer, M. Germine, D.O. Hurtubise, et al (Environmental Research, 1980).

The study

• Authors: J.H. Puffer, M. Germine, D.O. Hurtubise, K.A. Mrotek, D.M. Bello
• Journal: Environmental Research
• Published: 1980;23(2):233-46
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This was a geological survey of rock, not a study of people. The authors examined bedrock from 18 quarries in the Central Serpentine District, a belt of serpentinite rock about 5 km wide along the Pennsylvania-Maryland state line near the Susquehanna River, to measure its content of asbestos-type minerals. The sites included abandoned asbestos quarries, chrome mines, talc quarries, and serpentinite rock and gravel quarries. Samples were examined with a hand lens, light and electron microscopes, and X-ray diffraction. Fiber veins visible in the quarries made up less than 2% of the rock by volume, but under the microscope fiber ranged from absent to about 60% by volume. Chrysotile was not detected in mesh- and bastite-textured serpentinites common in the eastern part. It was an important component of recrystallized rock common in the central and western parts; one rock group averaged about 50% chrysotile. Fibrous anthophyllite mostly ground into nonfibrous particles. The authors said they knew of no evidence directly linking this asbestos to any health hazard. They suggested potential local hazards may exist where the rock is exposed, as through quarrying. They did not sample air.

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: Geological field and laboratory survey of bedrock samples (mineral analysis; no human subjects)
• Who was studied: Bedrock from 18 quarries in the Central Serpentine District along the Pennsylvania-Maryland state line: two abandoned asbestos quarries, three abandoned chrome mines, one abandoned and two operating talc quarries, and two operating and eight abandoned serpentinite rock and gravel quarries
• Exposure: Naturally occurring asbestiform minerals in serpentinite bedrock, chiefly chrysotile and fibrous anthophyllite, measured by hand lens, petrographic (light) microscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy
• Main results:
  • Fiber veins visible in outcrop made up less than 2 vol% of the rock in each quarry examined
  • Under thin-section microscopy, fiber content was much higher than seen by eye, ranging from absent to about 60 vol%
  • Chrysotile was not noted in the primary-mesh and bastite-textured serpentinites abundant in the eastern sector of the district
  • Chrysotile was an important component of recrystallized ribbon- to bladed-textured serpentinites common in the central and western portions of the district
  • Stage 3 samples (locations 9 and 12) had the highest average chrysotile asbestos content of the four stages, about 50 vol% of the rock
  • In Stage 4 rock, chrysotile ranged from a trace to 49 vol% of the typical samples observed, averaging 19 vol%
  • Transmission electron microscope point counts showed about 49 vol% tubular chrysotile in a typical bladed mat serpentine sample from location 3
  • Megascopically fibrous anthophyllite was generally coarse and platy and ground into predominantly nonfibrous particles
  • Roughly half of the unpaved roads the team traveled in the map area were surfaced with serpentinite gravel
  • The authors found that polarized light microscopy could detect chrysotile only in relatively thick veins
  • The authors stated they were not aware of any evidence directly linking the district's asbestos to any health hazard
• The authors' conclusion: The authors suggested that potential health hazards may exist locally in parts of the district underlain by asbestos-rich bedrock, particularly where it is exposed through quarrying. They stated that the evidence warrants a closer look at how bedrock asbestos may reach people, and they planned to analyze soils, ground water and air.
• Limitations the authors state:
  • The authors did not sample the air along serpentinite-gravel roads for airborne fibers
  • X-ray diffraction may miss a considerable chrysotile content
  • Thin-section estimates sometimes differed from estimates based on powdered samples
  • In-depth transmission electron microscope analysis of whole serpentinite bodies was impracticable, so only selected samples were analyzed this way

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Santa Rita mine, Joaquin Ridge near Coalinga, California

All asbestos mines

Topics

Medical terms in this study, explained in our Lexicon: Serpentine Group.

Related studies

• Asbestos on Maryland's roads — A.M. Langer, A.N. Rohl, et al. (1978)
• Topsoil and urban dust pollution and toxicity in Taranto (southern Italy) industrial area and in a residential district — M. Trifuoggi, G. Pagano, et al. (2018)
• Environmental asbestos pollution related to use of quarried serpentine rock — A.N. Rohl, A.M. Langer, et al. (1977)
• Asbestos: trouble in the air from Maryland rock quarry — L.J. Carter (1977)
• Exploration of the role of heat activation in enhancing serpentine carbon sequestration reactions — M.J. McKelvy, A.V. Chizmeshya, et al. (2004)
• Analysis of airborne dust samples for chrysotile by X-ray diffraction: interference by non-asbestiform serpentine — A.P. Middleton (1982)

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