Hearing loss in workers exposed to carbon disulfide and noise.

Abstract

Simultaneous exposure to carbon disulfide and noise may have a combined effect on hearing impairment. In this study we investigated hearing loss in 131 men with exposure to noise [80-91 A-weighted decibels; dB(A)] and CS 2 (1.6-20.1 ppm) in a viscose rayon plant. These men were compared with 105 men in the adhesive tape and electronic industries who were exposed to noise only and with 110 men employed in the administrative office of the rayon plant who were exposed to low noise and no CS 2 . We conducted interviews to obtain sociodemographic information and exposure assessments, and we performed physical examinations, including hearing tests. Results showed that the prevalence of hearing loss of > 25 dB hearing loss (dBHL) in rayon workers (67.9%) was much higher than that in administrative workers (23.6%) and in the adhesive tape and electronic industrial workers (32.4%). Hearing loss occurred mainly for speech frequencies of 0.5, 1, and 2 kHz. When the CS 2 exposure was measured by the product of CS 2 exposure level and employment years, the adjusted odds ratios of hearing loss of > 25 dBHL in rayon workers, compared with administrative workers, were 3.8 [95% confidence interval (CI), 1.5-9.4] for those with the exposure of 37-214 year-ppm, 14.2 (95% CI, 4.4-45.9) with 215-453 year-ppm exposure, and 70.3 (95% CI, 8.7-569.7) with exposure of > 453 year-ppm. The study suggests that CS 2 exposure enhances human hearing loss in a noisy environment and mainly affects hearing in lower frequencies.

Chemical exposure and hearing loss

“…Several clinical and epidemiological studies confirmed an association between exposure to solvents (styrene, toluene, xylenes, solvent mixtures, and jet fuels) in the workplace and increased prevalence of hearing loss, as well as poor hearing thresholds beyond the traditional 4 kHz noise-related audiometric notch. [83][84][85][86][87][88][89][90][91][92] For an extensive review of human studies, see Johnson and Morata 93 (available online at https:// gupea.ub.gu.se/handle/2077/23240).…”

Perda auditiva associada à exposição ocupacional a solventes orgânicos: uma revisão sistemática

“…An apparent doseresponse association between carbon disulfide and HL was reported by Chang et al 28 : exposure levels greater than 14.6 ppm might increase the effects of noise exposure on workers' hearing. In the study by Fuente et al 34 , groups of subjects working at different intensities -minimum, moderate and maximum -of exposure to solvent mixture showed progressively worse audiometric thresholds as they were exposed to higher intensities.…”

“…These hearing evaluation parameters did not show significant variation between types of exposure, whether to a single solvent or a solvent mixture. However, the prevalence or risk of developing OHL was higher among individuals exposed to "solvent(s) and noise" [10][11][12]20,28,[31][32][33]40 and "noise and two solvents" 11,13 combinations.…”

“…However, the action of solvents on a wider range of the cochlear structure (0.25 to 8 kHz) was observed in several studies 13,22,28,30,34,36 , especially in the frequencies of 2 and 8 kHz 12,21,24,27,35,39,40 . In one study there was no statistically significant difference between subjects exposed and not exposed to solvents concerning hearing impairment in PTA; however, auditory thresholds were worse in the groups exposed to solvents 37 .…”

“…One study evaluated the adverse effects of carbon disulfide on the hearing of workers of a silk viscose factory 28 , finding an apparent dose-response association. Carbon disulfide levels greater than 14.6 ppm increased the effects of noise exposure on hearing (OR=35 in exposures associated with noise above the tolerance limit).…”