title: Analysis of potential influence factors on background urinary benzene concentration among a non-smoking, non-occupationally exposed general population sample.
abstract: OBJECTIVE
  Analytical difficulties and lack of a biological exposure index and reference values have prevented using unmetabolized urinary benzene (UB) excretion as a biomarker of low-level environmental exposure. To explore what environmental factors beyond active smoking may contribute to environmental exposure to benzene, we monitored UB excretion in a non-smoking, non-occupationally exposed sample of the general population.
  
  
  METHODS
  Two spot urine samples were obtained from 86 non-smoking, non-occupationally exposed subjects, selected among a random sample of the general population of the metropolitan area of Cagliari (Sardinia, Italy), at 8:00 a.m. (UBm) and 8:00 p.m. (UBe). UB was measured by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry analysis. Questionnaire information on personal and environmental exposures during the sampling day was gathered with personal interviews. Multivariate analysis of variance and multiple regression model were applied to investigate the role of such variables on the level of UB.
  
  
  RESULTS
  The ninety-fifth percentile of UBe in this population was 311.5 ng/L, which is tentatively proposed as the UB guidance value for unexposed populations. UBm and urban residence were the only predictors of a significant increase in UBe excretion. Self-reported residential vehicular traffic will not account for the excess median value among urban residents; commuting time among urban residents showed a suggestive nonsignificant linear correlation with UBe, but the small sample size prevented reliable inference to be drawn. Age, environmental tobacco smoking, employment status and body mass index did not affect UB excretion.
  
  
  CONCLUSIONS
  Our findings support the use of unmetabolized UB as a specific and sensitive biomarker of low-level environmental exposure to benzene.
authors.affiliation: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico della Facoltà di Medicina, SS 554, km 4,500, 09042, Monserrato, Cagliari, Italy, makamp@libero.it.
authors.forename: Marcello
authors.initials: M
authors.lastname: Campagna
authors.forename: Giannina
authors.initials: G
authors.lastname: Satta
authors.forename: Laura
authors.initials: L
authors.lastname: Campo
authors.forename: Valeria
authors.initials: V
authors.lastname: Flore
authors.forename: Antonio
authors.initials: A
authors.lastname: Ibba
authors.forename: Michele
authors.initials: M
authors.lastname: Meloni
authors.forename: Maria Giuseppina
authors.initials: MG
authors.lastname: Tocco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Avataneo
authors.forename: Costantino
authors.initials: C
authors.lastname: Flore
authors.forename: Silvia
authors.initials: S
authors.lastname: Fustinoni
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Cocco
mesh_terms: D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000032:analysis / Q000652:urine*; D001554:Benzene / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D012111:Residence Characteristics; D012621:Seasons; D012737:Sex Factors; D012959:Socioeconomic Factors
chemical_list: D000393:Air Pollutants; D001554:Benzene