Hearing loss in shoemakers exposed to noise and solvent in Porto Alegre, Brazil

Abstract

Clinical and experimental studies indicate a possible harmful effect of chemicals, especially organic solvents, on the hearing system. In combined exposure to noise and solvents, very common in industry, it is most likely that a synergetic action of these factors enhances the traumatizing effect of exposure to noise. The aim of this study was to access the incidence and the risk of hearing impairment in 80 shoemakers. In this work we studied the effects of occupational exposure to solvent and noise in the hearing of workers of a factory in Porto Alegre, Brazil. In the studied group we analyzed solvents concentration in the air, biological marker for toluene in urine (hippuric acid), and levels of environmental noises. We analyze too the flow sheet of industrial production. The analysis of these results showed the bilateral hearing loss of 22.45%, and 18.37% in unilateral loss, in the workers of occupational exposure to toluene and noise, with levels allowed by the Brazilian legislation. The findings suggest that exposure to toluene and noise has a toxic effect on the auditory system. Further research is needed for the better understanding of the interaction of these and other agents in the auditory systems. [Work supported by CNq/FEPPS.]