Evaluation of benzene exposure in children living in Campania (Italy) by urinary trans,trans-muconic acid assay

The urinary benzene metabolite trans,trans-muconic acid (MA) was determined in 144 children living in Campania (Italy): 92 from Naples (1,300,000 inhabitants), designated as an urban source, and compared to 52 from Pollica (300 inhabitants), considered a rural, background exposure for benzene. The children participating in the study were tested by an anonymous questionnaire about the possible sources of exposure to benzene. Quantifiable levels of MA were found in 63% of the urine samples analyzed. Setting the value of nondetectable urinary samples at 7 microg/L MA, a value that is one-half of the instrument detection limit of 14 microg/L, the mean urinary concentration levels were 98.7+/-81.0 microg/L and 48.4+/-71.7 microg/L in Naples and Pollica, respectively; adjustment of these values to creatinine clearance resulted in MA levels of 141.2+/-145.4 microg/L in Naples and 109.8+/-133.2 microg/L in Pollica. Passive smoke exposure did not significantly affect urinary MA levels, but proximity of the home to traffic increased urine MA content. Data show that MA can be utilized as a biomarker for exposure; however, a clear-cut association to benzene requires personal monitoring and control of dietary sorbic acid.