[Comparative investigation of hearing injury in workers exposed to punching machine noise and to steady state noise].

OBJECTIVE: To compare the difference of effects on hearing injury between punching machine noise and steady state noise. METHODS: The subjects of present study were 100 workers, included 38 workers exposed to punching machine noise from forging shops and 62 workers exposed to steady state noise from drawbench or abrasive dust workshops. The individual noise dosimetries were used to detect noise that workers exposed, and cumulative noise exposure (CNE) was then calculated. On the basis of GBZ 49-2007, the worker hearing was tested, and the results were assessed. RESULTS: There were no differences of CNE between group exposed to punching machine noise and group exposed to steady state noise. The hearing loss rate (55.3%) at high frequency in workers exposed to punching machine noise was significantly higher than that (32.3%) in workers exposed to steady state noise (P < 0.01). CNE and the hearing loss rate at high frequency showed dose-response relationship (P < 0.01). CONCLUSION: when the exposure levels of workers were similar, the hearing injury induced by punching machine noise may be significantly higher than that induced by steady state noise.

[Low back pain prevalence of female workers in flat-grained veneer wood industry].

OBJECTIVE: To study the low back pain(LBP) and its cause on female workers in flat-grained veneer wood industry. METHODS: Bending posture was analyzed by observation and the prevalence of low back pain was investigated by physical examination and questionnaire among 299 female workers. RESULTS: The prevalence of fatigue compliant in selecting, remending and sticking workers was 68.8%, 66.7% and 59.0%, respectively, which mainly involved in the part of low back. The prevalence of low back pain in selection (53.8%) and remending (58.7%) workers was higher than that in sticking workers (30.1%), which was in accordance with the tenderness between L4/L5 or L5/L6 and on the psoas major. Posture analysis indicated that the biggest bending range of selecting and remending workers (80 degrees ) was larger than that of sticking workers (60 degrees ), as well as the daily bending times[(4396+/-817), (1696+/-286), (1094+/-476)] and the time they kept bending[(6.5+/-0.6), (6.2+/-1.3), 4.5+/-0.9) h]. CONCLUSION: Bending posture is common among female workers especially those who work in selecting and remending and might be the major causes for the high prevalence of LBP in flat-grained veneer wood industry.