Exposure Assessment to Respirable Free Silica in Coal Mining Areas: A Health Risk Assessment Approach

The International Agency for Research on Cancer (IARC) has classified free silica/quartz as a Group 1 carcinogen, indicating sufficient evidence of its carcinogenicity in humans. In the present study, suspended particulate matter (SPM), respirable dust (PM ₁₀ ), and free silica content in dust were assessed to determine the associated exposure risk in three mega coal mines (Bharatpur, Kaniha, and Lingaraj OCP) of the Talcher Coalfield located in Odisha, India. The respirable dust samples collected on the filter paper were analyzed using Fourier transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometer (EDS) to characterize their composition and morphology. The highest concentrations of SPM and PM ₁₀ were observed at Bharatpur OCP, with a mean value of SPM and PM ₁₀ of 394 µg/m ³ and 136 µg/m ³ , respectively. In contrast, Kaniha OCP exhibited slightly lower concentrations for SPM and higher concentrations of PM ₁₀ , with mean values of 230 µg/m ³ and 193 µg/m ³ , respectively. When compared with Bharatpur OCP, the highest concentration of free silica was observed at Kaniha OCP, with values ranging from 5.94 µg/m ³ to 114.89 µg/m ³ and a mean concentration of 41.59 µg/m ³ . The health risk assessment, conducted using USEPA methodology, indicates that Kaniha OCP poses the highest risks of exposure to respirable silica, with both non-carcinogenic and carcinogenic outcomes, followed by Bharatpur OCP. In contrast, the Lingaraj OCP exhibited comparatively lower health risk levels. The SEM/EDS analysis showed clear evidence of the presence of respirable free silica particles across all three mining sites.