Occupational noise-induced hearing loss of workers in a bauxite mine in India

Noise exposure from workplace can cause occupational noise-induced hearing loss (ONIHL) which begins at higher frequencies and gradually extends to lower frequencies. The aim of this study was to investigate the ONIHL among a highly mechanized bauxite mine employees from Odisha, India and to identify the possible determinants of ONIHL. A total of 247 personnel were tested for hearing loss at various frequencies (500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz) using PC-based digital audiometer between April 2014 and December 2015. Statistical analysis was conducted using SYSTAT 13.0. The study revealed that the industrial noise level exceeded the permissible limit during the operational hours and is likely to cause noise-induced hearing loss. Audiometric results reveal that a total of 85 out of 247 (34% )workers were found to have ONIHL in the age group of 28 to 63 years; from these, 43 of 57 (75%) work as operators followed by 27 of 58 (47%) charge-man, 12 of 92 (13%) technicians and 3 of 24 (12%) foreman. Study indicated a significant relation between occupation, industrial noise levels and duration of exposure in development of ONIHL among miners.