trans,trans-Muconic acid excretion in relation to environmental exposure to benzene

Potential environmental sources of benzene exposure, and intake of foods and beverages susceptible to being preserved with sorbic acid, were investigated in relation to their contribution to the inter-individual variation in background urinary trans,trans-muconic acid ( t,t-MA) excretion among subjects non-occupationally exposed to benzene.

We measured urinary t,t-MA excretion in 65 subjects, 34 women and 31 men. A spot sample of morning urine was collected for each subject 10-12 h after they had consumed their last meal. Questionnaire information was collected on diet and possible sources of environmental benzene exposure in the surroundings of the subjects' residences. For each subject, an estimate of the average daily intake of sorbic acid with diet was calculated, based on questionnaire information and laboratory data on samples of local food items.

The t,t-MA geometric mean was significantly higher among women (28.7 vs 11.5 microg/g creatinine, P<0.05) and among smokers (37.6 vs 15.6 microg/g creatinine, P<0.05), and increased by years of education among women, but not among men. In the multivariate analysis, smoking was the only significant predictor of elevated t,t-MA excretion. In our study, the average estimated daily sorbic-acid intake with diet was 0.33 ppm (standard deviation: 0.28), and it did not show a correlation with t,t-MA excretion. Urban traffic and residence within 100 m of a fuel station also did not show an association with elevated t,t-MA values.

Our study confirms that, among subjects non-occupationally exposed to benzene, smoking contributes significantly to increased background t,t-MA excretion. Further studies should be addressed to confirm our observation of elevated t,t-MA levels among women.