Geological occurrence, mineralogical characterization, and risk assessment of potentially carcinogenic erionite in Italy

Our plain-English summary of Geological occurrence, mineralogical characterization, and risk assessment of potentially carcinogenic erionite in Italy, by M. Giordani, M. Mattioli, P. Ballirano, et al (Journal of Toxicology and Environmental Health. Part B, Critical Reviews, 2017).

The study

• Authors: M. Giordani, M. Mattioli, P. Ballirano, A. Pacella, M. Cenni, M. Boscardin, L. Valentini
• Journal: Journal of Toxicology and Environmental Health. Part B, Critical Reviews
• Published: 2017;20(2):81-103
• Type of article: Review
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Erionite is a zeolite representing a well-known health hazard. In fact, exposure of humans to its fibers has been unequivocally associated with occurrence of malignant mesothelioma. For this reason, a multi-methodological approach, based upon field investigation, morphological characterization, scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) chemical analysis, and structure refinement through X-ray powder diffraction (XRPD), was applied to different samples of potentially carcinogenic erionite from Northern Italy. The studied crystals have a chemical composition ranging from erionite-Ca to erionite-Na and display variable morphologies, varying from prismatic, through acicular and fibrous, to extremely fibrous asbestiform habits. The fibrous samples were characterized by an unusual preferred partition of aluminum (Al) at tetrahedral site T1 instead of tetrahedral site T2. Further, a mismatch between the a-parameter of erionite-Ca and levyne-Ca that are intergrown in the asbestiform sample was detected. This misfit was coupled to a relevant micro-strain to maintain structure coherency at the boundary. Erionite occurs in 65% of the investigated sites, with an estimated quantity of 10 to 40 vol% of the associated minerals. The presence of this mineral is of concern for risk to human health, especially if one considers the vast number of quarries and mining-related activities that are operating in the zeolite host rocks. The discovery of fibrous and asbestiform erionite in Northern Italy suggests the need for a detailed risk assessment in all Italian areas showing the same potential hazard, with specific studies such as a quantification of the potentially respirable airborne fibers and targeted epidemiological surveillance.

In plain English

This article combined laboratory analysis of rock samples with a review of where erionite, a zeolite mineral that can form fibers, has been reported in Italy. The authors examined minerals that had formed in cavities of volcanic basalt in the Lessini Mountains, in the Veneto region of north-east Italy. They studied more than one thousand cavities in the field and sampled about 300. They reported erionite in 65% of the outcrops investigated, making up an estimated 10 to 40 percent by volume of these minerals. Four representative samples were analyzed with electron microscopy and, for two of them, X-ray diffraction. One sample (MC35) had solid, rigid crystals with no fibrous elements. The other three split into fibers or fibrils. The finest (BV201) formed fibrils about 5 to 85 micrometers long and under 0.3 micrometers wide, grown together with another zeolite, levyne. The study did not measure airborne fibers or examine anyone's health. The authors concluded that the findings suggest the need for a detailed risk assessment in Italy, including measurement of airborne fibers and targeted epidemiological surveillance. They noted that these basalts host mines and quarries and are used as construction material.

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 survey and laboratory mineralogical characterization of rock samples (no human or animal subjects), combined with a review of reported erionite locations in Italy
• Who was studied: Secondary minerals in cavities (vesicles) of Tertiary basalts in the Lessini Mountains, Veneto region, NE Italy. More than 1,000 vesicles were studied in the field, about 300 were sampled, and four representative erionite samples (MC35, MF2, MB170, BV201) were analyzed in detail.
• Exposure: Erionite (a zeolite, here erionite-Ca and erionite-Na) in rock, ranging from prismatic through acicular and fibrous to extremely fibrous forms. No human exposure or airborne fiber levels were measured.
• Main results:
  • Erionite was present in 65% of the investigated outcrops, with an estimated amount of 10 to 40 vol% of total secondary minerals
  • Sample MC35 (erionite-Ca) consisted of solid, rigid prismatic crystals with no fibrous elements detected
  • Sample MF2 was erionite-Na made of needle-like crystals that tended to separate into rigid fibers and fibrils, commonly thinner than about 1.5 micrometers
  • Sample MB170 (erionite-Ca) contained many small fibrils with rigid to flexible behavior, up to about 30 micrometers long and with diameters smaller than 1 micrometer
  • Sample BV201 (erionite-Ca, intergrown with levyne) separated into thin fibers and fibrils about 5 to 85 micrometers long (main mode 40 to 60 micrometers) and less than 0.3 micrometers in diameter
  • Structurally, MB170 showed an unusual preferred placement of aluminum at the T1 site instead of T2
• The authors' conclusion: The authors concluded that the discovery of fibrous erionite in the Lessini Mountains suggests the need for a detailed risk assessment in Italy, including quantification of potentially airborne fibers and targeted epidemiological surveillance. They noted that these basalts often host mining or quarrying and are used as construction material.
• Limitations the authors state:
  • Structural results for sample BV201 were considered less accurate because it was a roughly 50:50 mixture of erionite and levyne
  • A reliable chemical composition of the levyne in BV201 could not be obtained because of the small crystals and intergrown structure
  • A detailed description and quantification of erionite across all these areas is still lacking
  • Available epidemiological data follow administrative borders, not the limits of erionite-bearing rock, so the authors could not extract mesothelioma incidence for the Lessini Mountains area

Topics

Medical terms in this study, explained in our Lexicon: Carcinogenic, erionite, Zeolite, Malignant Mesothelioma, Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Acicular, Asbestiform.

Related studies

• Erionite series minerals: mineralogical and carcinogenic properties — A.U. Dogan, M. Dogan, et al. (2008)
• 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)
• Global geological occurrence and character of the carcinogenic zeolite mineral, erionite: A review — J.P. Patel, M.S. Brook, et al. (2022)
• Occurrence, behaviour, and human exposure pathways and health risks of toxic geogenic contaminants in serpentinitic ultramafic geological environments (SUGEs): A medical geology perspective — W. Gwenzi (2020)
• Lung diseases due to environmental exposures to erionite and asbestos in Turkey — S. Emri, A. Demir, et al. (2002)
• 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)

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