Environmental Exposure to Xylenes in Drivers and Petrol Station Workers by Urinary Methylhippuric Acid

Abstract Background: The aims of this study were evaluation of exposed to xylenes in low concentration and com pare urinary level of methyl hippuric acid in taxi drivers and petrol stations workers in West of Iran. Methods: This observation study was carried out on samples of the exposed men to xylenes in two oc-cupational groups in Hamadan City (west of Iran) from March 2003 to March 2004. Subjects included 45 taxi drivers and 25 petrol station workers. The study group was selected from 54 workers at petrol sta tions and 300 drivers by simple random sampling. Xylenes was analyzed using gas chromatography equipped with a Flame Ionization Detector (FID). The urinary methyl hippuric acid (MHA) was ana lyzed with High performance Liquid Chromatography (HPLC) equipped with an ultraviolet (UV) de tector. Results: Total xylene exposure was 1.05±0.55 ppm (mean±SD) with a range of 0.20-2.55 ppm that was about 4 times more than taxi driversʹ exposure. The poor correlation coefficient was seen between xy lenes concentration and urinary MHA for drivers (r2= 0.09 to 0.42) but significant associations were noted between urinary MHA and xylene in the breathing zone of petrol station workers (r2= 0.69 to 0.77; P < 0.05). Conclusion: High xylenes levels are emitted in petrol stations at Iran. Urinary MHA level has a poor correla tion with exposure to xylenes in drivers but has good correlation in petrol station workers.