Determination of urinary trans, trans-muconic acid reference values in general Tunisian population.

We wish to determine the urinary, trans,trans-muconic acid reference values in the Tunisian general population, and evaluate the impact of several factors (age, gender, tobacco...) on these reference values. Urine samples were collected from 182 healthy Tunisian subjects who had not been occupationally exposed to benzene. This determination was performed by solid phase extraction sampling technique together with high performance liquid chromatography-photodiode array detector. Trans,trans-muconic values ranged from 0.003 to 0.618 mg/g creatinine, the 95% reference interval was: 0.004-0.36, and the 90% confidence interval of the upper reference limit was: 0.24-0.62 mg/g creatinine. Urinary trans,trans-muconic levels were significantly higher among smokers. Significant differences were also observed for the < 20 and the >= 40 age groups. As a result urinary trans,trans-muconic background levels allow the biomonitoring of workers occupationally exposed to benzene at levels as low as 0.5 ppm. Age and tobacco, but not gender may affect the trans,trans-muconic reference values.