Dimensional characteristics of the major types of amphibole mineral particles and the implications for carcinogenic risk assessment

Abstract

Context: Though some significant advances have been made in recent decades to evaluate the importance of size and morphology (habit) of elongate mineral particles (EMPs), further research is needed to better understand the role of each dimensional metric in determining the levels of cancer potency.

Objective: To determine dimensional parameters most relevant for predicting cancer potency of durable elongate particles, specifically amphibole and durable silicate minerals generally.

Methods: A database on dimensional and other relevant characteristics of elongate amphibole mineral particles was created, containing particle-by-particle information for 128 099 particles. Integral statistical characteristics on dimensionality of various amphibole types and morphological habits of EMPs were calculated, compared, and correlated with published mesothelioma and lung cancer potency factors.

Results: The highest absolute Pearson correlation (r = 0.97, r² = 0.94, p < 0.05) was achieved between mesothelioma potency (R_M) and specific surface area. The highest correlation with adjusted lung cancer potency was found with particle aspect ratio (AR) (r = 0.80, r² = 0.64, p < 0.05). Cluster analysis demonstrates that fractions of thin fibers (width less than 0.15 and 0.25 µm) also closely relate both to lung cancer and R_M. Asbestiform and non-asbestiform populations of amphiboles significantly differ by dimensionality and carcinogenic potency.

Conclusions: Dimensional parameters and morphological habits of EMPs are the main drivers for the observable difference in cancer potency among amphibole populations.

Keywords:

• Elongate mineral particles
• asbestiform fibers
• mineral fragments
• mesothelioma
• lung cancer
• dimensionality
• specific surface area

Disclosure statement

The article utilized the database created as a part of the project ‘Fibrous minerals database development and statistical analysis of various characteristics relevant for the prediction of toxicity’ sponsored by National Stone, Sand and Gravel Association (NSSGA). Dr. Andrey Korchevskiy participated in this project as a scientist. NSSGA never impacted the content of the database, the study’s outcomes, or any aspects of this article. Professor Ann Wylie has never received any compensation for any part of the preparation of this article.