The auditory effects of chemical toxicants have been investigated in the past two decades, in animal and human field and clinical studies. A number of studies demonstrated that some solvents, metals, asphyxiants, pesticides not only affect the sensory organ of the auditory system, as noise does, but also affect central auditory structures. Ototoxicity induces outer hair cell dysfunction in the cochlea (similar to the effects of noise), whereas neurotoxicity induces central auditory dysfunction. Audiological signs of neurotoxicity may or may not include poorer hearing thresholds, in addition to difficulties discriminating sounds such as speech, particularly in adverse listening conditions. The existing evidence prompted the proposal of new guidelines and standards on hearing loss prevention. In the U.S., the National Institute for Occupational Safety and Health has discussed specific research needs regarding the ototoxicity of chemicals used at work. The American Conference of Governmental Industrial Hygienists and the U.S. Army have proposed preliminary practical steps that employers and occupational health professionals can take to improve hearing loss prevention. Australia and New Zealand have developed standards recommending hearing tests for workers exposed to ototoxic agents. In the legislative arena, the European Parliament published a new noise directive (2003/10/EC), that requires employers to give attention to any effects on workers' health and safety resulting from interactions between noise and work-related ototoxic substances, when performing risk assessment of workplaces. Legislation regarding compensation has also changed in Australia and Brazil . In this presentation the auditory effects of chemical alone or in combination with noise will be reviewed, and the recent guidelines, legislative developments and alternative strategies for the prevention of auditory effects resulting from exposure to chemicals in the workplace will be presented.
Toxicology; Chemical-properties; Noise-induced-hearing-loss; Ototoxicity; Auditory-system; Toxic-materials; Cell-alteration; Cell-damage; Cellular-function; Ear-disorders; Neurotoxic-effects; Neurotoxicity; Hearing; Hearing-impairment; Hearing-loss; Hearing-threshold; Hearing-acuity; Sound; Injury-prevention; Hearing-tests; Hearing-protection; Health-standards; Medical-research; Safety-research; Standards; Regulations; Legislation; Noise; Noise-exposure
The Toxicologist. Society of Toxicology 52nd Annual Meeting and ToxExpo, March 10-14, 2013, San Antonio, Texas