Erionite in road gravel associated with interstitial and pleural changes--an occupational hazard in western United States

Our plain-English summary of Erionite in road gravel associated with interstitial and pleural changes--an occupational hazard in western United States, by P.H. Ryan, M. Dihle, S. Griffin, et al (Journal of Occupational and Environmental Medicine, 2011).

The study

• Authors: P.H. Ryan, M. Dihle, S. Griffin, C. Partridge, T.J. Hilbert, R. Taylor, S. Adjei, J.E. Lockey
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2011;53(8):892-8
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To determine the rate of chest radiographic abnormalities among residents of North Dakota potentially exposed to road gravel containing the fibrous mineral erionite.

Methods: Participants (n = 34) completed a questionnaire, chest radiograph, and high resolution computed tomography scan to assess the rate of interstitial and pleural changes consistent with fibrous mineral exposure.

Results: Interstitial, pleural, or both changes typically associated with asbestos exposure were observed by high resolution computed tomography in seven (21%) individuals. The primary exposure pathway for six of these was from gravel pits, road maintenance, or both. Three participants (8.8%) demonstrated bilateral localized pleural changes with calcification; two of these also had accompanying interstitial changes. All three reported extensive work in gravel pits, road maintenance, or both.

Conclusions: These results indicate that occupational exposure to erionite contained within road gravel in the United States represents a potential health hazard.

Clinical Significance: This study identifies chest radiographic changes among residents of North Dakota occupationally exposed to road gravel containing erionite. Public health officials and physicians in affected areas should be aware of the potential health effects of erionite exposure. Precautionary measures should be taken to limit occupational exposure to gravel containing erionite.

In plain English

This study looked for chest changes in western North Dakota residents possibly exposed to erionite, a fibrous mineral, in road gravel. Of 34 participants, 15 had high potential for prolonged gravel exposure; other potentially exposed residents were added. For 15, the main exposure was gravel pit or road maintenance work. Most had chest X-rays and high resolution CT (HRCT) scans; one had HRCT only, another a conventional CT. On 33 available chest X-rays, interstitial and localized pleural changes were each seen in one (3.0%), neither significantly increased. On HRCT, interstitial changes appeared in 6 people (17.6%), significantly above a 1.5% comparison rate. The authors judged four of these six unlikely to be erionite-related. Three people (8.8%), all mainly exposed through gravel pit or road maintenance work, had bilateral localized pleural changes with calcification. This was elevated but not statistically significant against 3.4% (P = 0.11). One of the three also had past Navy asbestos exposure. The authors concluded the results suggest occupational exposure to erionite-containing road gravel can result in pleural and possible interstitial changes. The authors cited the lack of personal air sampling as a limitation.

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: Cross-sectional radiographic screening study (questionnaire, chest X-ray and HRCT scan), with observed rates compared with published background rates
• Who was studied: 34 current or former residents of western North Dakota recruited as potentially exposed to erionite-containing road gravel. 15 (44%) had high potential for prolonged gravel exposure; other potentially exposed residents were enrolled to increase sample size. 26 (76.5%) were male; average age 61 years (range 40 to 80).
• Exposure: Road gravel containing the fibrous mineral erionite. The most frequent primary exposure pathway (15 participants, 44.1%) was work in gravel pits, road maintenance or both. Other pathways were frequent driving (7), ranching or farming (6) and other (6). Average time since first exposure was 34 years and average duration was 22 years.
• Main results:
  • Not every participant had both tests: one had HRCT only, and one had a conventional CT scan and chest X-ray
  • On chest X-ray, interstitial changes were seen in 1 of 33 available films (3.0%), not a significant increase
  • On chest X-ray, localized pleural changes were seen in 1 participant (3.0%), not above the background rate of 3.9%
  • On HRCT, interstitial changes were seen in 6 participants (17.6%), significantly increased (P < 0.01) compared with a 1.5% rate in male transportation workers
  • The authors judged it unlikely that the minimal interstitial changes in four of the six were related to erionite, citing smoking history, an atypical pattern or short time since first exposure
  • On HRCT, 3 participants (8.8%) had bilateral localized pleural changes. This was elevated but not statistically significant (P = 0.11) compared with a 3.4% rate.
  • The primary exposure pathway for these three participants was gravel pits, road maintenance or both
  • One of the three participants with pleural changes (participant 12) also had asbestos exposure as a US Navy boiler technician
  • Without that participant, 2 participants (6.1%) had bilateral pleural changes
• The authors' conclusion: The authors concluded that the results suggest occupational exposure to road gravel containing erionite, particularly for road maintenance and gravel pit workers, can result in pleural and possible interstitial changes historically associated with commercial asbestos exposure
• Limitations the authors state:
  • Participants' airborne erionite exposure was not measured, and there were no personal sampling data
  • There are no background rates of asbestos-type pleural changes on HRCT for North Dakota or the US population

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: erionite, Interstitial, Chest X-Ray, Asbestos Exposure, Bilateral, Occupational Exposure.

Related studies

• Geologic occurrences of erionite in the United States: an emerging national public health concern for respiratory disease — B.S. Van Gosen, T.A. Blitz, et al. (2013)
• Erionite exposure in North Dakota and Turkish villages with mesothelioma — M. Carbone, Y.I. Baris, et al. (2011)
• Lung diseases due to environmental exposures to erionite and asbestos in Turkey — S. Emri, A. Demir, et al. (2002)
• Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors — M. Metintas, G. Hillerdal, et al. (2010)
• High incidence of lung cancer and malignant mesothelioma linked to erionite fibre exposure in a rural community in Central Mexico — M.A. Ortega-Guerrero, G. Carrasco-Núñez, et al. (2015)
• Erionite series minerals: mineralogical and carcinogenic properties — A.U. Dogan, M. Dogan, et al. (2008)

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