Failure of urinary trans,trans-muconic acid as a biomarker for indoor environmental benzene exposure at PPB levels

Benzene is a widespread pollutant whose main source in the environment is a utomotive emission. There is increasing interest in the exposure of the pop ulation to this pollutant as benzene is present also in the indoor environm ent due to cigarette smoke, drinking water, and food. The aim of this study was to evaluate, in an adult nonsmoking population not occupationally expo sed to benzene, whether it is possible to detect differences in the urinary concentration of trans, trans-muconic acid (t,t-MA) between low and high e nvironmental exposure to benzene. A study sample of 31 employees working in pharmacies in a large town in Italy with low environmental exposure to ben zene (4.8 mug/m(3)) was compared to a high (8.1 mug/m(3)) benzene exposure group. Analysis of urinary t,t-MA was carried out by high-performance liqui d chromatography ( HPLC; photodiode array detector); analysis of environmen tal benzene samples was by gas chromatography/ mass spectroscopy (GC-MS). T he statistical analysis revealed no significant differences in urinary leve ls of t,t-MA of subjects with high (mean concentration: 157.9 mug/g(creatin ine)) versus low exposure (mean concentration: 114.2 mug/g(creatinine)). Da ta show that it is difficult to correlate urinary t,t-MA with benzene expos ure at parts per billion levels.