Characterization of Fibrous Mordenite: A First Step for the Evaluation of Its Potential Toxicity

Abstract

In nature, a huge number of unregulated minerals fibers share the same characteristics as asbestos and therefore have potential adverse health effects. However, in addition to asbestos minerals, only fluoro-edenite and erionite are currently classified as toxic/pathogenic agents by the International Agency for Research on Cancer (IARC). Mordenite is one of the most abundant zeolites in nature and commonly occurs with a fibrous crystalline habit. The goal of this paper is to highlight how fibrous mordenite shares several common features with the well-known carcinogenic fibrous erionite. In particular, this study has shown that the morphology, biodurability, and surface characteristics of mordenite fibers are similar to those of erionite and asbestos. These properties make fibrous mordenite potentially toxic and exposure to its fibers can be associated with deadly diseases such as those associated with regulated mineral fibers. Since the presence of fibrous mordenite concerns widespread geological formations, this mineral fiber should be considered dangerous for health and the precautionary approach should be applied when this material is handled. Future in vitro and in vivo tests are necessary to provide further experimental confirmation of the outcome of this work.

Pathogenic Potential of Respirable Spodumene Cleavage Fragments following Application of Regulatory Counting Criteria for Asbestiform Fibres

“…For several decades extensive research has been dedicated to understanding the mechanisms of disease induction following the inhalation of naturally occurring mineral fibres [ 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. There is strong evidence indicating that length is the critical factor in determining the carcinogenic potential of mineral fibres [ 30 , 53 , 54 , 73 ] rather than mineralogical origin or chemical composition [ 19 , 54 ].…”

Global geological occurrence and character of the carcinogenic zeolite mineral, erionite: A review

“…The World Health Organization (WHO, 1997) also specifies a diameter (w) of <3 μm for particles to be inhalable, and fiber diameter is a critical dimension as the smaller the diameter, the higher the particulate number per unit mass of dust, which will increase the inhalation potential of the fibers (WHO, 1997). The diameter also influences the ability of phagocytes to clear fibers from the respiratory tract, and the density of the fiber aids in determining its aerodynamic diameter (d ae ), which influences the depositional depth of fibers within the respiratory tract (WHO, 1986(WHO, , 1984James et al, 1994;Brown, 2015;DeWitt et al, 2016;Belluso et al, 2017;Gualtieri et al, 2017;Di Giuseppe, 2020). The aerodynamic diameter, as defined by Gonda and Abd El Khalik (1985) and modified by Di Giuseppe (2020), is:…”

“…where d = fiber diameter, β = aspect ratio (L/w), ρ = particle density, and ρ 0 = unit density (1 g/cm 3 ; Di Giuseppe, 2020; Gualtieri et al, 2017). The aerodynamic diameter is critical as not only can it determine where in the respiratory tract a fiber is likely to be deposited, but it also assists in determining the inhalability of a fiber (Millage et al, 2010;Gualtieri et al, 2017;Di Giuseppe, 2020). The inhalability of fibers is important as it determines if a particle may be able to enter the body (Millage et al, 2010).…”

The in vitro cytotoxic effects of natural (fibrous epsomite crystals) and synthetic (Epsom salt) magnesium sulfate

“…Some mineral fibers such as asbestos (chrysotile, amosite, crocidolite, asbestos anthophyllite, asbestos tremolite and asbestos actinolite) and zeolites, in particular erionite, have been extensively investigated in the last decades (e.g., Cangiotti et al, 2017, 2018; Gualtieri, 2023; World Health Organization, 1986; Thompson et al, 2017; Mirata et al, 2022) and classified as a carcinogen for humans (class 1) by International Agency for Research on Cancer (IARC, 2012). For other minerals such as ferrierite (Gualtieri, 2018; Mattioli et al, 2022; Zoboli et al, 2019), mordenite (Di Giuseppe, 2020; Giordani, Ballirano, et al, 2022), offretite (Giordani et al, 2019; Mattioli et al, 2018), scolecite (Mattioli et al, 2016), mesolite and thomsonite (Betti et al, 2022; Giordani, Mattioli, et al, 2022), and others (e.g., fluoro‐edenite, winchite, richterite, clay minerals; Gianfagna et al, 2003; NIOSH, 2011; Erskine & Bailey, 2018; Larson et al, 2016), the current knowledge does not permit an accurate risk classification. Exposure to mineral fibers represents a serious environmental hazard strictly correlated to fibrotic pulmonary diseases, pneumoconiosis, and various types of cancer in exposed subjects (Aust et al, 2011; Di Giuseppe et al, 2021; Gualtieri et al, 2017).…”