بررسي ارتباط بين صدا و افت شنوايي در كارگران نورد ذوب آهن اصفهان

The Relationship Between Noise and Noise induced Hearing Loss in the Isfahan Forging Industries Workers

One of the most impairment aspect in occupational health is the study of noise induced hearing loss (NIHL} in noise exposed workers. The study was carried out to find out relation and a model between noise exposed workers and NIHL in 1997. To determine N1HL in the worker in loom-650, 45 workers having no confounding factors were choosen. All the study population were examined using audiometer. Result showed the SPL range was 70-105 dBA. The average of work experience were 10.3±3.5 and age 37.4±6.7 years. Correlation coefficient between job history and NIHL in the left ear was 0.7099 and in the right ear was 0.7127. The Pearsonʹs correlation coefficient between left and right ear was positive and equal to 0.69. The mean of NIHL between right and left ear was 14 dB which the regression model predicts the limit of hearing loss in left ear is 4.5 years and in right ear is 3.8 years. Although the results showed loss of hearing begins in right ear, but left ear had more hearing loss with increasing of experience years. The danger limit for hearing of these workers (based on 25 dB loss), for left ear and right ear were after 1 7 and 20.7 years of work experience respectively. To prevent serious impairment in the workers hearing, it is suggested to consider the limit of 17 yearʹs occupancy in forging as a base for changing the occupancy.