[Auditory threshold and the degree of its temporary and permanent shifts in the textile industry workers]

Abstract

Hearing threshold was measured with digital audiometer CASK-431 in transportable soundproof booth GIG-AU-1 in 170 women and 75 men before and at the end of the afternoon shift work in the weaving-mill with shuttle looms, where an average noise level was 100 dB(A). The average hearing losses calculated from the formula dB (1000 Hz + 2000 Hz + 4000 Hz): 3 were higher than those calculated from the formula db (500 Hz + 1000 Hz + 2000 Hz): 3. There was also a higher correlation coefficient between the occupational exposure to noise and the values of hearing loss calculated according to the former of the mentioned formulae, as compared to the latter. Workers wearing individual hearing protectors from the glass microfibres suffered from temporary threshold shift (TTS) of few dB whereas in those wearing no hearing protectors the TTS attained 10 to 24 dB on average. Among the women--workers of comparable age and occupational exposure to noise the hearing losses were higher in those living in noisy communities than in those living in quiet communities. This result is indicative of cumulative effects of community and industrial noise in respect to the hearing damage. Regulations for permissible noise levels in occupational environment should involve the kind of exposure to the community noise.