title: [Assessment of urinary trans, trans-muconic acid as a biomarker of exposure to benzene].
abstract: OBJECTIVE
  To assess the use of trans, trans-muconic acid as a biomarker of occupational exposure to benzene.
  
  
  METHODS
  Trans, trans-muconic acid in urine samples of exposed (exposed group, n=36) and non-exposed (non-exposed group, n=116) workers to benzene. Urinary levels of trans, trans-muconic acid were quantified by high-performance liquid chromatography. The study sample consisted of subjects exposed to benzene in an oil refinery in Belo Horizonte, Brazil. Non-parametric statistical analysis was carried out using Kruskall-Wallis test, Mann-Whitney test and Spearman correlation at p<0.05.
  
  
  RESULTS
  Workers were exposed on average to benzene levels of 0.15 +/- 0.05 mg/m3 (0.05 ppm) and they showed a urinary trans, trans-muconic acid mean value of 0.19 +/- 0.04 mg/g of creatinine. The reference value range of trans, trans-muconic acid in non-exposed subjects was 0.03 to 0.26 mg/g of creatinine (mean 0.10 +/- 0.08 mg/g of creatinine). There was seen a statistical difference between trans, trans-muconic acid levels in urine samples from exposed and non-exposed groups. There was no correlation between urinary trans, trans-muconic acid and air benzene levels. There was no correlation between urinary trans, trans-muconic acid levels in the exposed group and smoking. Alcohol consumption up to 48 hours before sampling procedure showed no effect on trans, trans-muconic acid levels in both exposed and non-exposed groups. There was however a correlation between age (range 18 to 25 years) and urinary metabolite levels in the latter group.
  
  
  CONCLUSIONS
  The results show that it is important to evaluate the effect of age and smoking habits on urinary trans, trans-muconic acid levels.
authors.affiliation: Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil. depaulaflavia@ig.com.br
authors.forename: Flávia Cristina S
authors.initials: FC
authors.lastname: de Paula
authors.forename: Josiane Nicácio
authors.initials: JN
authors.lastname: Silveira
authors.forename: Roberto Gonçalves
authors.initials: RG
authors.lastname: Junqueira
authors.forename: Edna Maria Alvarez
authors.initials: EM
authors.lastname: Leite
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000395:Air Pollutants, Occupational / Q000378:metabolism / Q000633:toxicity*; D001554:Benzene / Q000378:metabolism / Q000633:toxicity*; D015415:Biomarkers / Q000652:urine; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D012907:Smoking / Q000652:urine; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000032:analysis*
chemical_list: D000395:Air Pollutants, Occupational; D015415:Biomarkers; C005939:muconic acid; D001554:Benzene; D013011:Sorbic Acid