الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Organic solvents (OS) are liquids consisting of one substance or more (i.e. mixture). Fuel station environment exposes workers to multiple risks and several health hazards. These risks are mainly due to contact with gasoline as it is the main source of fuel in fuel stations.
Gasoline is a mixture of low molecular mass compounds of which Benzene, Toluene, Ethylbenzene and Xylene (BTEX) are considered the most hazardous components.
Inhibition of the vestibulo-ocular reflex (VOR) has been reported as a very early sign of central nervous system (CNS) intoxication, a defect that could be easily noticed by Videonystagmography (VNG) tests.
Biological monitoring (BM) is an accu¬rate method for evaluation of occupational exposure to OS and an important measure for the pre¬vention and control of occupational diseases. Urinary trans, trans-mu¬conic acid (t,t-MA) is a useful biomarker for bio¬monitoring of benzene exposure.As for toluene, it is metabolized to hippuric acid (HA) which is excreted in urine.Methyl hippuric acid (MHA) and mandelic acid (MaA) are measured as urinary biomarkers for exposure to xylene and ethylbenzene respectively.
Complaints, such as vertigo and dizziness have been observed in fuel station workers.These symptoms might lead to increased work-related slips and falls through alteration of mechanisms involved in balance control regulation and postural stability.The need of studying the effects of occupationalexposure to BTEX on the vestibular system becomes worthwhile.
The aim of this study is to assess the vestibular system among workers with chronic exposure to organic solvents in fuel stations.
The study was carried on 140 workers divided into two equal groups.To all workers included in the study, detailed history taking and thorough physical examination were done. They were alsosubjected to hearing and balance tests. Urinary metabolites were detected to prove exposure and blood antioxidant levels were also measured.
Results were tabulated and statistical analysis was done which revealed statistically significant difference between both exposed and non-exposed groups concerning the PTA, VNG, urinary metabolites of BTEX and blood levels of MDA and TAC. Also it was found that the duration of exposure directly affects the vestibular system.Our results are in agreement with most of the previously done similar studies.
In conclusion: the present study demonstrated the possible OS exposure effects on both hearing and balance control. More studies are required to define whether balance disorder in organic solvents exposed workers is of peripheral origin, central origin or both and what is the exact mechanism that cause the injury.