Evaluation of Urinary Metabolites of Volatile Organic Compounds and Some Related Factors in Petrochemical Industry Workers

Background and purpose: Biological monitoring for workers exposed to solvents includes complementary environmental monitoring which is useful in toxic chemical risk assessments. The aim of this study was environmental and biological monitoring of workers exposed to volatile organic compounds (VOCs) in petrochemical industry. Material and Methods: Air and urine samples were collected from 104 individuals working in petrochemical industry. NIOSH 2549 method was used to determine the concentrations of benzene, toluene, xylene isomers, phenol, and methyl ethyl ketone in breathing environment. In order to determine the concentration of urinary metabolites, urine samples were analyzed by high performance liquid chromatography and gas chromatography. Urinary creatinine level was measured by UV-VIS spectrophotometer. To analyze the data t-test and linear regression were performed in SPSS V.16. Results: The mean concentrations of benzene, toluene, O and m-xylene, P-xylene, phenol and methyl ethyl ketone in breath samples were 1.192, 1.300, 1.97, 1.290, 0.0116, and 2.243 ppm, respectively. The mean concentrations of urinary trans, t- MA, hippuric acid, 2, 3 and 4-methyl hippuric acid, and phenol were 1431 µgr/grCr, 0.3949, 0.4444, 0.1483 gr/grCr, and 0.5850mgr/grCr creatinine, respectively. Concentrations of urinary methyl ethyl ketone were 0.154 mgr/lit. There was a direct linear relationship between concentration of VOCs in the air and urinary metabolites (P<0.05). The results showed that increase in working hours per week resulted in increased level of urinary t, t- MA, methyl hippuric acid isomers and phenol (P<0.05). Conclusion: The mean concentration of benzene in breathing environment, urinary t, and t- MA was higher than the ACGIH's Threshold Limit Values (TLV) and Biological Exposure Indices (BEI) while the mean concentrations of other compounds were lower than TLV and BEI. We also found that smoking increased urinary excretion of all metabolites expect hippuric acid.