Urinary biomarkers and low-level environmental benzene concentration: Assessing occupational and general exposure Anna Barbieri * , Francesco Saverio Violante, Laura Sabatini, Francesca Graziosi, Stefano Mattioli Unit of Occupational Medicine, Sant’Orsola Malpighi Hospital, University of Bologna, 40138 Bologna, Italy article info Article history: Received 22 May 2008 Received in revised form 4 August 2008 Accepted 4 September 2008 Available online 14 October 2008 Keywords: Biomonitoring Unmetabolized benzene S-Phenylmercapturic acid Smoking habit abstract The categories of urban workers undergoing prolonged exposure to gasoline due to vehicle emissions, evaporation and traffic fumes are considered occupationally exposed to benzene, even if at low concen- trations. The aim of this study was to evaluate the specificity of unmetabolized benzene excreted in urine (UBz) and S-phenylmercapturic acid (SPMA) as biomarkers of exposure to very low levels of benzene, and to study the impact of putative individual confounders like smoking and alcohol habits, co-exposure to other toxicants and body mass index on the exposure assessment. Environmental and biological monitor- ing of exposure to benzene were performed in 114 Urban Policemen. The mean value of UBz in non- smokers was significantly lower than in either groups of light to moderate smokers and heavy smokers (0.24, 1.82 and 2.82 lgL 1 , respectively). On the contrary, SPMA values did not discriminate exposure resulting from smoking habits. Moreover, the concentration of UBz in non-smokers appears to be corre- lated with environmental benzene concentration (BenzA) (R 2 = 0.13, b = 0.37, p = 0.002). On the other hand, no significant correlation was found between SPMA concentration (corrected for creatinine excre- tion and log transformed, LogSPMA) and LogBenzA (R 2 = 0.003, b = 0.05, p = 0.6). Our findings reinforce previous research on the use of unmetabolized urinary benzene as a specific and sensitive biomarker of low-level exposure to benzene and confirm that smoking habits strongly influence the excretion of UBz. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Benzene is the primary and most dangerous source of contam- ination in urban air. Its toxicity and carcinogenicity has been estab- lished (Group 1, IARC, 1987) and its leukemogenic activity in humans is known. It is derived from a variety of sources, such as city traffic, car refuelling and smoking (both active and passive). Trace amounts of benzene are also in food, as a result of certain types of cooking (e.g. barbecuing and grilling) (Johnson et al., 2007). Over the last few years, many governmental legislations have sought to reduce the limits both for occupational (0.5 ppm TLV-TWA, ACGIH, 2008) and environmental exposure. The Euro- pean Commission has developed an ‘‘air quality standard” (AQS) for benzene and established a background (or ‘‘ambient”) concentration of benzene in the air (5 lgm 3 ) related to minimum health risk for the general population. Since automotive fuel com- position plays an important role in pollutant emissions, an Italian regulation, published in 1997, prohibits the sale of gasoline that contains benzene at a concentration exceeding 1% by volume. However, a lot of vehicles do not have catalytic converter yet and a large quantity of benzene is probably emitted through exhaust pipes. Therefore, urban workers undergoing prolonged exposure to gasoline due to vehicle emissions, evaporation and traffic fumes are considered occupationally exposed to benzene, even if at low concentrations. Fustinoni et al. (2005a,b) reported a mean expo- sure value to benzene of 22 lgm 3 in a group of Milan traffic policemen and a value of 21 lgm 3 in a group of Genoa bus driv- ers. Scientific evidence showed that low levels of airborne benzene could also increase the leukemogenic risk in the general popula- tion, in particular in weak categories such as children (Steffen et al., 2004). Although urban areas usually have a non-homogenous environmental pollution pattern, environmental monitoring data provide reliable information on the general population’s exposure (Violante et al., 2006). Furthermore, since several studies high- lighted the role of other sources of benzene, such as cigarette smoking, lifestyle and food habits (Johnson et al., 2007), it would be relevant to understand and evaluate their contribution to the 0045-6535/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2008.09.011 Abbreviations: UBz, urinary concentration of unmodified benzene; UTol, urinary concentration of unmodified toluene; SPMA, urinary concentration of S-phenyl- mercapturic acid corrected for creatinine excretion; BenzA, environmental concen- tration of benzene; TolA, environmental concentration of toluene. * Corresponding author. Address: Dipartimento di Medicina Interna, dell’Invec- chiamento e Malattie Nefrologiche, Università di Bologna – Unità Operativa di Medicina del Lavoro, Via Palagi, 9, 40138 Bologna, Italy. Tel.: +39 051 636 2755; fax: +39 051 636 2609. E-mail address: anna.barbieri3@unibo.it (A. Barbieri). Chemosphere 74 (2008) 64–69 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere