158 Coachbuilding and painting shop workers' co-expositionto noise and ototoxic substances. risk evaluation and prevention. (24th April 2018) - Daumas, Renée
Abstract : Introduction: Coachbuilding and painting shop workers are co-exposed to noise and ototoxic substances thereby producing synergistic adverse effects on hearing, which might increase the risk of professional hearing loss. A previous investigation showed that most of employers and workers ignore those risks due to occupational activities, or negligences. Methods: 60 volunteers were measured in 24 shops. We used dosimeters for evaluating the noise exposures, and passive badges for the amount of solvents inhaled by each worker during a workday. CAS DPOAE suppression (Echoscan) allowed auditory fatigue to be assessed by summing several sources: metabolic fatigue from hair cells, afferent and efferent fibres, central nuclei (SOC and facial), and obviously from middle-ear muscles. The trigger threshold variations of workers exposed to both noise and solvents were measured with Echoscan twice a day. In the meantime, the wearing of auditory and respiratory individual protectors was monitored. Results: The Lex8h measurements were higher than 80, 85, 87 dB(A) for 33, 17, 12% of tested workers, respectively. Toluene, ethylbenzene and xylene constituted the most used ototoxics. These findings are in agreement with the data collected in the French database COLCHIC for carshops' workers. Taken separately each solvent exposure was inferior to its legal threshold limit value, but an exposure to a chemical cocktail may affect the hair cells or the central nuclei. Results showed that data obtained with Echoscan were sensitive both to noise and solvents. At the end of a working day, trigger threshold variations of workers exposed to both noise and solvents were significantly lower than those measured in workers exposed to noise only. Workers and shop observation showed significant neglects in collective and individual prevention. Conclusion: Difficulties to characterise workers' effective exposure are numerous in car shops. Regarding employers and workers' awareness, a primary prevention has been launched through information sessions. Auditory fatigue depends on the nature of the exposure. A co-exposure impacts the trigger threshold variations of CAS DPOAEs.