Respiratory Effects of Simultaneous Exposure to Respirable Crystalline Silica Dust, Formaldehyde, and Triethylamine of a Group of Foundry Workers

Background: Foundry workers are occupationally exposed to hazardous substances such as silica dusts and toxic gases. The aim of this study was to examine the effects of simultaneous exposure to complex mixtures of silica dust, formaldehyde, and triethylamine on lung function parameters. Study design: A cross-sectional study. Methods: This study was conducted on 55 male workers of core making unit of a foundry plant (the case group) and 55 workers in a food industry were enrolled as a control group in 2015. Workers were monitored for personal exposure to crystalline silica respirable dust, according the NIOSH method No.7602. The concentrations of formaldehyde and triethylamine were measured using a PID instrument. Lung function tests were performed according to the ERS/ATS standards. Results: The mean concentrations of personal exposure to silica dust, formaldehyde, and triethylamine in the core making workers were 0.23 mg/m3, 2.85 ppm, and 5.55 ppm and respective exposures of control subjects were less than the LOD (limit of detection). There were significant associations between exposure to silica dust and decreases in FVC (Forced vital capacity) values (P<0.05). The findings showed a statistically significant synergistic effect of silica dust and triethylamine on FVC values (P<0.05). Conclusions: The mean exposure of all studied substances was higher than occupational exposure limits. Synergistic effects of exposure to silica dust and triethylamine on some lung function parameters were observed. Simultaneous exposure of foundry workers to silica dust and triethylamine could impair lung function.