title: Assessment of the correlation between exposure to benzene and urinary excretion of t, t-muconic acid in workers from a petrochemical plant.
abstract: OBJECTIVE
  The investigation covered 148 workers from three plants with different levels of benzene exposure. The aim of the study was to assess the correlation between workers' personal exposure and urinary excretion of t, t-muconic acid (TTMA).
  
  
  METHODS
  The personal exposure to benzene was measured by the sampling of the workplace air on sorbent tubes with active charcoal followed by elution with carbon disulphide and gas chromatographic determination. The individual internal exposure was assessed by determination of TTMA in urine by a liquid chromatographic method. The urine samples were collected at the beginning (t(0)) and end (t(1)) of the work shift.
  
  
  RESULTS
  The individual whole-shift concentrations of benzene in workplace air in the three studied facilities varied from 0.1 to 67.53 mg/m(3). The concentration of TTMA at the beginning of the shift (t(0)) was from 0.02 to 2.53 mg/l and at the end of the shift (t(1)) was from 0.02 to 9.96 mg/l. Significant correlation was found between benzene level in workplace air and TTMA concentration in urine at the end of the work shift, with a correlation coefficient r=0.425 ( P=0.01).
  
  
  CONCLUSIONS
  The analysis of the obtained results shows that TTMA can be used as a biological indicator for benzene exposure. The registered single cases of workers with unexpectedly high results for t, t-muconic acid are explained by their consumption of canned foods containing sorbic acid as a preservative. The subjects involved in similar studies should be advised not to consume canned foods 12 h before the examination.
authors.affiliation: Department of Toxicology, National Center of Hygiene, 15 D Nestorov Boulevard, 1431 Sofia, Bulgaria.
authors.forename: Teodor
authors.initials: T
authors.lastname: Panev
authors.forename: Todor
authors.initials: T
authors.lastname: Popov
authors.forename: Tzveta
authors.initials: T
authors.lastname: Georgieva
authors.forename: Diana
authors.initials: D
authors.lastname: Chohadjieva
mesh_terms: D001554:Benzene / Q000009:adverse effects*; D015415:Biomarkers / Q000032:analysis; D002273:Carcinogens / Q000009:adverse effects*; D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D007536:Isomerism; D016273:Occupational Exposure; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000032:analysis* / Q000493:pharmacokinetics; D016482:Urinalysis; D017132:Workplace
chemical_list: D015415:Biomarkers; D002273:Carcinogens; C005939:muconic acid; D001554:Benzene; D013011:Sorbic Acid