Health Effects of Censored Elongated Mineral Particles: A Critical Review

Abstract

Detection limits for asbestos and elongated mineral particles (EMPs) necessarily depend on what “counts” by a given test method or procedure. Censored data in this context include both fibers that fall below and outside of a laboratory’s counting criteria. For microscopic methods, in particular, counting criteria may be based on health effects, methodological convenience, or geologic definition. For purposes of public health, data censorship for asbestos or EMPs should be predicated on the toxicity of the fibers and not on a geologic definition. Some geologic definitions of EMPs are inconsistent with existing evidence of EMP toxicity. For this study, we used systematic search techniques and grounded theory to review published studies, government records, corporate documents, and public statements. Research links asbestos health effects to fiber dimensions, fiber surface area, biopersistence, chemical composition, and surface properties. We review the evidence that indicate that short fibers (<5 µm long), thin fibers (<0.2 µm wide), some nonasbestos EMPs, and asbestos mineral “cleavage fragments” affect human health. Current EMP test methods allow the censorship of these fibers from reported data. We believe that a health perspective is crucial for determining what data to censor in the measurement of EMPs. Fiber-counting methods should be altered to better encompass health-relevant EMPs by employing transmission electron microscopy, eliminating the requirement for an asbestiform habit, including short fibers (<5 µm long), and removing all minimum fiber width criteria. EMP test methods should explicitly call for counting talc and erionite fibers.

Laser ablation inductively coupled plasma mass spectrometry as a novel clinical imaging tool to detect asbestos fibres in malignant mesothelioma

“…9 This asbestos classification was created to facilitate the counting of the MF using standard microscopy methods and was not based on the potency of these segments or shorter fibres to induce ARD. 10 According to the latest guidelines published by the British Thoracic Society, the current investigation workflow involves an urgent chest X-ray of symptomatic patients, followed by a pleural evaluation computerised tomography (CT) scan, immunohistochemistry of biopsies or cytology-type specimens, and establishing the prospect of occupational exposure or para exposure to asbestos fibres. 11 However, it is essential to detect MF in lung tissues to complete the pathological diagnosis of MPM in correlation to asbestos exposure.…”

“…This does not account for cleavage fragments, or high potency shorter fibres 9 . This asbestos classification was created to facilitate the counting of the MF using standard microscopy methods and was not based on the potency of these segments or shorter fibres to induce ARD 10 …”

A Critique of Helsinki Criteria for Using Lung Fiber Levels to Determine Causation in Mesothelioma Cases

“…They also "did not record and retain a photographic record of any of the fibrous structures encountered [34]". Short fibers (less than 5 µm) have been shown to be carcinogenic and are concentrated in the pleura [3,39].…”

Asbestos in Talc and Mesothelioma: Review of the Causality Using Epidemiology

“…38 (Exec Summary p. V-VI) Egilman et al 39 systematically reviewed EMPs, cleavage fragments, short fibers, thin fibers, erionite and fibrous talc according to their potential to cause adverse human health effects. Using the Hill 40 criteria for potential to be causal in health effects, Egilman et al 39 concludes that all fiber types should be counted in laboratory mineral sample detection methodology. Finkelstein 41 examined two samples of Mouldene industrial talc.…”