Trends in exposure to respirable dust and respirable crystalline silica among lithium mine workers in Western Australia

Abstract

Background: Exposure to respirable dust (RES) and respirable crystalline silica (RCS) is common in mining operations and is associated with health effects such as pneumoconiosis, chronic obstructive pulmonary disease (COPD), interstitial pulmonary fibrosis, silicosis, lung cancer, and renal disease. Methods: This study used industry occupational exposure data for respirable dust from two surface lithium mines in Western Australia for the period between 2017 and 2023. A total of 1122 samples were collected in workgroups across four departments - administration and support, mining, crushing and processing, and maintenance.

Results: The study found that the overall RES concentration did not exceed the exposure standard. However, Crusher Dry/Wet Plant Personnel (0.558 mg/m3) and Workshop Boilermakers (0.842 mg/m3) recorded elevated exposure to RES. The highest mean exposures for RCS over the seven-year study period were measured for Management Administration & Technical (0.068 mg/m3), followed by Crusher Dry/ Wet Plant Personnel (0.042 mg/m3), exceeding the ES. Maximum results for both RES (15.00 mg/m3) and RCS (2.50 mg/m3) indicated exceedances.

Conclusion: The study demonstrated a decline in exposure to RES over the seven years of study from 0.472 mg/m3 to 0.151 mg/m3, with a slight increase in 2019 and 2022. A decline in the concentration of RCS was observed between 2019 -2021, followed by an increase after 2021. The mean concentration of RCS exceeded the exposure standard in 2023. Based on the study results and the established adverse health effects associated with exposure to silica, various control measures to protect workers from RCS exposure should be considered.