Occupational Exposure to Erionite

by

David N. Weissman

• LAST REVIEWED: 26 April 2018
• LAST MODIFIED: 26 April 2018
• DOI: 10.1093/obo/9780199756797-0181

Introduction

Erionite provides an excellent example of the public health importance of recognizing, evaluating, and reporting disease outbreaks caused by previously unrecognized hazards, enabling disease to be prevented through control of harmful exposures. The term “erionite” describes a mineral series within the group of silicate minerals called zeolites, which are crystalline, hydrated aluminosilicates with crystalline structures characterized by linked tetrahedra consisting of four oxygen atoms surrounding a cation. These structures contain open cavities that are usually occupied by water molecules and extra-framework cations. Commercial usefulness of zeolites is based on their adsorption, cation exchange, dehydration-rehydration, and catalytic properties. There are more than eighty naturally occurring zeolites. Three individual species of erionite have been defined, erionite-Ca, erionite-K, and erionite-Na. One way in which erionite can crystallize is as needle-like fibers or bundles of fibers that are morphologically similar to asbestos fibers. When disturbed, these fibers can become airborne and be inhaled. Recognition of this as a public health hazard came due to a mesothelioma epidemic affecting a group of small villages in the Cappadocia region of Turkey, where rocks containing erionite are common and have been used for purposes such as constructing homes and surfacing roads. Based in large part on scientific literature investigating this epidemic, the International Agency for Research on Cancer (IARC) has found that erionite is carcinogenic to humans (Group 1), causing pleural and peritoneal mesothelioma. Furthermore, erionite appears to have a higher potency for inducing mesothelioma than asbestos. In the small Turkish cohorts, mesothelioma deaths far outnumbered deaths from other types of cancer. Rat inhalation studies reviewed by IARC showed increased mesothelioma but not lung cancer. Thus, although IARC noted that mortality data showed the possibility that erionite might cause additional types of cancer, it only found sufficient evidence for mesothelioma. In addition to mesothelioma, erionite exposure is associated with asbestos-like nonmalignant health effects. Inhalation of erionite fibers can cause pleural reactions such as calcified pleural plaques and fibrosing pleurisy. Pulmonary interstitial fibrosis has also been reported in some exposed people. The findings and conclusions in this report are those of the author and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

General Overviews

Several of the listed reviews provide helpful general overviews of erionite mineralogy and health effects (International Agency for Research on Cancer 2009; National Toxicology Program 2016; Rezvani and Bolduc 2014). In addition, several provide in-depth information about specific aspects of erionite and its health effects. Mumpton 1999 provides an excellent historical review of the commercial usefulness of zeolites. International Agency for Research on Cancer 2009 provides an in-depth review of research evaluating human and animal carcinogenicity of erionite, in particular research evaluating mesothelioma risk in residents of Cappadocia, Turkey. Carbone, et al. 2007 and Emri 2017 review efforts to identify environmental and genetic risk factors and address erionite-related mesothelioma in Cappadocia, Turkey. Demirer, et al. 2015 is a systematic review and excellent source of references on pathogenesis, diagnosis, and treatment of erionite-related malignant mesothelioma.

• Carbone, M., S. Emri, A. U. Dogan, et al. 2007. A mesothelioma epidemic in Cappadocia: Scientific developments and unexpected social outcomes. Nature Reviews Cancer 7.2: 147–154.

  DOI: 10.1038/nrc2068

  Review of efforts to investigate and address the problem of mesothelioma in three small Turkish villages in Cappadocia, Turkey, where the disease accounted for 50 percent of all deaths. Outlines work to define the combined roles of erionite exposure and genetic predisposition to mesothelioma.

• Demirer, E., C. F. Ghattas, M. O. Radwan, and E. M. Elamin. 2015. Clinical and prognostic features of erionite-induced malignant mesothelioma. Yonsei Medical Journal 56.2: 311–323.

  DOI: 10.3349/ymj.2015.56.2.311

  Systematic review of literature published on erionite-related malignant mesothelioma. Excellent source of references on pathogenesis, diagnosis, and treatment.

• Emri, S. A. June 2017. The Cappadocia mesothelioma epidemic: Its influence in Turkey and abroad. Annals of Translational Medicine 5.11: 239.

  DOI: 10.21037/atm.2017.04.06

  A very informative personal account of efforts to address mesothelioma in Cappadocia, Turkey, including research to identify erionite exposure and genetic risk factors as causes, public health interventions, and impact beyond Turkey, particularly in the United States.

• International Agency for Research on Cancer. 2009. Erionite. In A review of human carcinogens: Arsenic, metals, fibres, and dusts. Monographs on the Evaluation of Carcinogenic Risks to Humans 100C. Lyon, France: International Agency for Research on Cancer.

  Provides a brief overview of erionite properties and an extensive review of evidence regarding the carcinogenicity of erionite in humans and in animal studies.

• Mumpton, F. A. 1999. La roca magica: Uses of natural zeolites in agriculture and industry. Proceedings of the National Academy of Sciences of the United States of America 96.7: 3463–3470.

  DOI: 10.1073/pnas.96.7.3463

  Provides an excellent history of the commercial uses of zeolites.

• National Toxicology Program. 2016. Erionite. In Report on carcinogens. 14h ed. CAS No. 66733-21-9. Research Triangle Park, NC: US Public Health Service.

  Provides a general review of erionite properties, usage, exposure, and cancer studies in humans and experimental animals.

• Rezvani, N., and D. L. Bolduc. 2014. Erionites. In Reference module in biomedical sciences: Encyclopedia of toxicology. 3d ed. Edited by P. Wexler, M. Abdollahi, A. de Peyster, et al., 448–452. Amsterdam: Elsevier.

  This chapter provides a general review of erionite mineralogy and the epidemiology and toxicology of adverse health effects associated with exposure. Available online for purchase or by subscription.