Assessment of the physicochemical properties of chrysotile-containing brake debris pertaining to toxicity

Boyles, Matthew S. P.; Poland, Craig A.; Raftis, Jennifer; Duffin, Rodger

Abstract

Grinding and drilling of chrysotile asbestos-containing brake pads during the 20thcentury led torelease of chrysotile, resulting in varying levels of workplace exposures of mechanics. Despite expo-sures, excess risk of mesothelioma remains in doubt.
Objectives:The toxicity of particulates is primarily derived through a combination of physicochemicalproperties and dose and as such this study aimed to determine properties of asbestos-containingbrake debris (BD) which may influence pathogenicity and potential of mesothelioma.
Materials and Methods:Chrysotile-containing brake pads were ground–to reflect occupational activ-ities, aerosolized, and size-fractionated to isolate respirable fractions. Analysis of morphology, biodur-ability, surface charge, and interactions with macrophages were undertaken.
Results:The respirable fraction of BD contained15–17% free chrysotile fibers thereby constituting asmall but relevant potential long fiber dose. Acellular biodurability studies showed rapid dissolutionand fragmentation of chrysotile fibers that was consistent for pure chrysotile control and BD samples.
Conclusions:The long, free, respirable chrysotile fibers were present in BD, yet were of low bio-dur-ability; incubation in artificial lysosomal fluid led to destruction of free fibers.

Citation

Boyles, M. S. P., Poland, C. A., Raftis, J., & Duffin, R. (2019). Assessment of the physicochemical properties of chrysotile-containing brake debris pertaining to toxicity. Inhalation Toxicology, 31(8), 325-342. https://doi.org/10.1080/08958378.2019.1683103

• Journal Article Type: Article
• Acceptance Date: Oct 17, 2019
• Online Publication Date: Nov 5, 2019
• Publication Date: 2019
• Deposit Date: Oct 13, 2023
• Publicly Available Date: Oct 13, 2023
• Journal: Inhalation Toxicology
• Print ISSN: 0895-8378
• Electronic ISSN: 1091-7691
• Publisher: Taylor & Francis
• Peer Reviewed: Peer Reviewed
• Volume: 31
• Issue: 8
• Pages: 325-342
• DOI: https://doi.org/10.1080/08958378.2019.1683103
• Keywords: Brake debris; chrysotile asbestos; fiber; toxicity;mesothelioma