Efficacy of Urinary Hippuric Acid as a Biomarker of Low Level Exposure to Toluene in Petroleum Depot Workers
Exposure to toluene can be associate with genotoxicity, neurological dysfunction, reproductive toxicity, and etc. Biomonitoring of hippuric acid (HA) is used for a long time as an occupational exposure index to toluene. The aim of this study was to explore efficiency of HA as a biomarker of exposure to low level of toluene for Iranian Petroleum Depot workers in 2011. Personal monitoring to toluene exposure for 45 workers (exposed group) and 32 staff (control group) were done according to the NIOSH Method No.1501, and simultaneous biological monitoring were conducted as urinary HA for all subjects. Pre and post shift urine samples were collected for analysis of HA by the NIOSH method No.8300 and urinary HA concentrations were corrected with creatinine content. Personal exposure of petroleum loading operators to toluene was 0.78±0.37ppm (Mean±SE). There was no statistical significant difference between urinary HA of exposed and control groups (staff). There was no statistical correlation between occupational exposure to toluene and internal exposure in term of HA. Occupational exposures to toluene were less than TLV in petroleum products loading operators. Due to exposure with low levels of toluene concentrations, however the content of urinary HA in gasoline operators were higher than BEI (Biological Exposure Index), but of no significant relationship between airborne concentrations of toluene and levels of HA in urine in all exposed groups. In conclusion, urinary HA is not appropriate biomarker of low level exposure to toluene.
Jackson MM. Organic liquids storage tanks volatile organic compounds (VOCS) emissions dispersion and risk assessment in developing countries: the case of Dar-Es-Salaam City, Tanzania. Environ Monit Assess 2006. 116(1-3): 363-382.
MoroAM, Brucker N, Charão M, Bulcão R, Freitas F, Baierle M, et al. Evaluation of genotoxicity and oxidative damage in painters exposed to low levels of toluene. Mutation Research 2012;746(1):42-8.
WiwanitkitV, Suwansaksri J, Srita S, Fongsoongnern A. High levels of hippuric acid in the urine of Thai press workers. Southeast Asian J Trop Med Public Health 2002;33(3):624-7.
GerickeC, Hanke B, Beckmann G, Baltes MM, Kühl K-P, Neubert D. Multicenter field trial on possible health effects of toluene: III. Evaluation of effects after long-term exposure. Toxicology 2001;168(2):185-209.
FustinoniS, Mercadante R, Campo L. Self-collected urine sampling to study the kinetics of urinary toluene (and o-cresol) and define the best sampling time for biomonitoring. Int Arch Occup Environ Health 2009;82(6):703-13.
Pandya G, Gavane A, Kondawar V. Assessment of occupational exposure to VOCs at the gantry gasoline terminal. J Environ Sci Eng 2006;48(3):175.
Holmberg B, Lundberg P. Benzene: standards, occurrence, and exposure. Am J Indust Med 1985;7(5-6):375-83.
DucosP, Berode M, Francin J, Arnoux C, Lefèvre C. Biological monitoring of exposure to solvents using the chemical itself in urine: application to toluene. Int Arch Occup Environ Health 2008;81(3):273-84.
BarrDB, Wilder LC, Caudill SP, Gonzalez AJ, Needham LL, Pirkle JL. Urinary creatinine concentrations in the US population: implications for urinary biologic monitoring measurements. Environ Health Perspect 2005;113(2):192.
HaysSM, Aylward LL. Using biomonitoring equivalents to interpret human biomonitoring data in a public health risk context. J Appl Toxicol 2009;29(4):275-88.
PierceCH, Chen Y, Dills RL, Kalman DA, Morgan MS. Toluene metabolites as biological indicators of exposure. Toxicology Letters 2002;129(1):65-76.
UkaiH, Kawai T, Inoue O, Maejima Y, Fukui Y, Ohashi F, et al. Comparative evaluation of biomarkers of occupational exposure to toluene. Int Arch Occup Environ Health 2007;81(1):81-93.
Ogata M, Tomokuni K, Takatsuka Y. Urinary excretion of hippuric acid and m-or p-methylhippuric acid in the urine of persons exposed to vapours of toluene and m-or p-xylene as a test of exposure. Br J Industr Med 1970;27(1):43-50.
LiuSJ, Qu QS, Xu XP, Liu YT, Yin SN, Takeuchi Y, et al. Toluene vapor exposure and urinary excretion of hippuric acid among workers in China. Am J Indus Med1992;22(3):313-23..
InoueO, Kanno E, Kasai K, Ukai H, Okamoto S, Ikeda M. Benzylmercapturic acid is superior to hippuric acid and o-cresol as a urinary marker of occupational exposure to toluene. Toxicology letters 2004;147(2):177-86.
McDermottHJ. Exposure Assessment Strategy and Monitoring Plan. Air monitoring for toxic exposures. John Wiley & Sons, Inc, 2004; pp 69-92.
AzariMR, Williams FM, Edwards PGBJW. Potential biomarkers of exposure and effect among glass craftsmen and braziers exposed to nitrogen oxides. Biomarkers 1997;2(6):349-54.
Ignacio JS, Bullock WH. A strategy for assessing and managing occupational exposures. 3rd ed, AIHA, 2006.
American Conference of Governmental Industrial Hygienists (ACGIH). TLVs & BEIs based on the documentation of the Threshold limit values for chemical substances and physical agents & biological exposure indices. Cincinnati, Ohio, USA 2011.
DuyduY, Süzen S, Erdem N, Uysal H, Vural N. Validation of hippuric acid as a biomarker of toluene exposure. Bull Environ Contam Toxicol 1999;63(1):1-8.
KawaiT, Yasugi T, Mizunuma K, Horiguchi Si, Ikeda M. Urinalysis vs. blood analysis, as a tool for biological monitoring of solvent exposure. Toxicology Letters 1992;63(3):333-43.
BahramiA, Jonidi-Jafari A, Folladi B, Mahjub H, Sadri Q, Zadeh MM. Comparison of urinary O-cresol and hippuric acid in drivers, gasoline station workers and painters exposed to toluene in west of Iran. Pak J Biol Sci 2005;8(7):1001-5.
IkedaM, Ohtsuji H. Hippuric acid, phenol, and trichloroacetic acid levels in the urine of Japanese subjects with no known exposure to organic solvents. Br J Industr Med 1969;26(2):162-4.
SiqueiraMEP, Paiva MJN. Hippuric acid in urine: reference values. Revista de Saúde Pública 2002;36(6):723-7.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.