Document R226Gb63zbYGK0Rpo80rJZj2E

Chemico-Biological Interactions 153154 (2005) 239242 Urban air and tobacco smoke in benzene exposure in a cohort of traffic policemen Roberto Bono a,, Deborah Traversi a, Luciano Maestri b, Tiziana Schiliro` a, Sergio Ghittori b, Claudio Baiocchi c, Giorgio Gilli a a Department of Public Health and Microbiology, University of Torino, Italy b Salvatore Maugeri Foundation, Laboratory of Environmental Hygiene and Industrial, Toxicology, Pavia, Italy c Department of Analytical Chemistry, University of Torino, Italy Available online 12 April 2005 Abstract Benzene (B) is a typical micro-pollutant present in air, especially urban air. In this study a possible correlation between personal benzene exposure and S-phenylmercapturic acid (S-PMA) as a biomarker of internal dose was evaluated in a cohort of traffic policemen. The results confirm that S-PMA is significantly correlated to benzene measured in personal air. B and S-PMA were analyzed considering seasonality, work quarters, time spent indoors, outdoors, and directing traffic, but no significant differences were recorded. 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Benzene; Traffic policemen; Biomarkers; Urinary S-phenylmercapturic acid 1. Introduction Benzene (B) is an ubiquitous micro-pollutant present primarily in air (99%). In particular, active smoke represents the most important source of B exposure for smokers, while, for nonsmokers, B exposure is principally due to outdoor ambient air, where B pollution is caused by auto exhaust or gasoline vapor emissions [1] and to indoor air where the presence of B is largely due to environmental tobacco smoke. B air pollution is a very important topic for environmental health due to its carcinogenic properties by all routes of exposure. Corresponding author. E-mail address: roberto.bono@unito.it (R. Bono). The aim of this study is to search for a possible correlation between personal passive exposure to B and levels of urinary S-phenylmercapturic acid (S-PMA) in a cohort of traffic policemen that, for their specific working functions, spend their time indoors and outdoors. Due to the presence of B in tobacco smoke, urinary cotinine as a confounding factor was also investigated in all the subjects. 2. Materials and methods The present study enrolled 206 volunteers among traffic policemen working in Turin, a city with 900,000 inhabitants located in north-western Italy. The enrolled 0009-2797/$ see front matter 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.cbi.2005.03.028 240 R. Bono et al. / Chemico-Biological Interactions 153154 (2005) 239242 subjects were also administered a questionnaire with questions including their smoking habits and the time spent during work in three kinds of environment: offices (indoor), in the streets (outdoor) and directing traffic (outdoor, close to high traffic volume). The sampling period lasted from March 2002 to April 2003. Each Thursday, six policemen wore a personal diffusive sampler able to measure air B exposures for a whole working shift. At the end of the working shift a questionnaire was administered and a urine sample was collected to measure S-PMA and cotinine as biomarkers of benzene and of tobacco smoke respectively. B was analyzed using a gas chromatograph (GC) Carlo Erba 5300 Mega Series equipped with a flame ionization detector (FID) and capillary column DB-624 30 m 0.318 mm i.d., film 1.8 m. Each sample was eluted using ultrapure carbon disulfide (CS2 99.9% low benzene content, Aldrich 34.227-0) (3 ml for air samples, 2 ml for personal monitor samples). A calibration curve was prepared from known concentrations of benzene, toluene, and xylenes. The GC thermal program was 45 C for 4 min, increase of 10 C/min, from 45 to 145 C, then 145 C for 2 min [2,3]. Urinary S-PMA was measured by a method already described elsewhere [4] and slightly modified in order to improve sensitivity. Briefly, samples were purified by a two-step protocol with reversed-phase (C18-EC) and with strong anionic exchange (SAX) solid-phase extraction cartridges. Then they were deacetylated by means of porcine acylase. After centrifugal ultrafiltration with disposable units (cut-off 10,000), the de-proteinized samples were derivatized for 5 min with the o-phthaldialdehyde/2-mercaptoethanol (OPAMCE) reagent and the fluorescent derivatives were separated by high-performance liquid chromatography (HPLC) on a reversed phase column. The limit of detection of the method was 0.2 g/l of S-PMA in urine. Urine samples were stored at -70 C until cotinine analysis was performed, within 6 months. In a centrifuge tube, 1 ml of NaOH 5 M, 8.5 g NaCl and 5 ml of chloroform were added to 25 ml of urine. The methodology for cotinine analysis and quality control was published previously [5]. Instrumental analysis was performed using a gas chromatograph (GC) equipped with a flame ionization-nitrogen-selective detector (NPD) using an oven programmed temperature rising from 100 to 250 C. The external quality control for the GC technique consisted in a re-analysis for 20 times of a cotinine standard solution added to a pool of nonsmokers' urine samples [6]. Results show a coefficient of variation (CV) of 4.3%, a detection limit below 1 ng/ml, and recovery around 100%. Pyridine was used as an internal standard for quality control. 3. Results The sites of work of the 206 policemen covered the entire municipal area of Turin involving both residential and traffic-congested areas. Subjects declared through a questionnaire their age (years 38 7), gender (male 60%), length of service (years 8.7 8). A general Pearson correlation analysis between number of cigarettes smoked per day and urinary cotinine showed that urinary cotinine is a sensitive and specific internal dose marker of tobacco smoke exposure (Fig. 1). Furthermore, the cotinine level in smokers and nonsmokers were 671 and 25 ng/ml, respectively (p < 0.0001). A general statistical distribution of B and S-PMA values are shown in Table 1. Linear regression and Pearson's coefficient r of the two parameters are reported in Fig. 2. Fig. 1. Regression analysis between number of cigarettes smoked per day and urinary cotinine for all the 206 subjects. Table 1 General statistical distribution of B and S-PMA values N Min Max Mean Benzene (g/m3) 206 0.1 65.0 8.8 S-PMA (g/g of creatinine) 206 0.3 8.1 1.5 S.D. 8.1 1.0 R. Bono et al. / Chemico-Biological Interactions 153154 (2005) 239242 241 Table 3 Comparison between S-PMA (g/g of creatinine) detected in other studies and in this study Boogaard and Melikian Ghittori Van Sitter [7] et al. [8] et al. [9] This study Smokers 3.6 Nonsmokers 1.9 9.1 7.8 2.3 4.8 1.0 1.2 Fig. 2. Regression analysis between personal benzene and S-PMA for all the 206 subjects. Table 2 Statistical comparison of B and S-PMA values sub-grouped by smoking habit Benzene (g/m3) Nonsmokers Smokers N 154 52 Mean S.D. t-Test 7.6 7.5 0.0001 12.7 8.6 S-PMA (g/g of creatinine) Nonsmokers 154 1.2 0.6 0.0001 Smokers 52 2.3 1.6 Taking smoking habits into account, t-test underlines a significantly higher level of B and S-PMA for smokers (Table 2). By means of ANOVA multivariate analysis, mean values of B and S-PMA were analyzed considering seasonality, work quarters, time spent indoors, outdoors, and directing traffic, but no statistically significant differences were recorded. thermore, the important role of tobacco smoke in the synthesis of S-PMA is, at this point, clear. Several measures were adopted by the European Community and, locally, by Turin municipality to prevent outdoor B exposure, in particular that arising from automobiles. In other studies, urinary S-PMA measured in smokers was higher, probably due to higher B exposure (Table 3). The data obtained in this study show that the subjects analyzed are exposed to low levels of B, as demonstrated by the low excretion of S-PMA in nonsmokers, independently from the working conditions. This study demonstrates also that, for traffic policemen, tobacco smoke is the main source of B exposure, as evidenced by the doubling of S-PMA excretion in smokers. These data have important implications for both prevention policy at work and against the tobacco smoking habit. Acknowledgement Thanks are given to all the traffic policemen of Turin city and in particular to the Commander-in-Chief Dr. Mauro Famigli. 4. Discussion and conclusions The present study confirms that the level of S-PMA is significantly correlated to benzene in personal air. The traffic policemen are a very useful human model able to represent different environments where people live and work. In particular, no differences were recorded considering either indoor or outdoor air exposure, or the direct exposure of traffic policemen to B pollution originating from vehicle exhaust. These data demonstrate, on one hand, the very low level of B contamination in outdoor air and, on the other hand, the not marginal level of B in indoor air (the offices). Fur- References [1] L. Wallace, Environmental exposure to benzene: an update, Environ. Health Perspect 104 (1996) 11291136. [2] R. Bono, E. Scursatone, T. Schiliro`, G. Gilli, Ambient air levels and occupational exposure to benzene, toluene and xylenes in Northwestern Italy, J. Toxicol. Environ. Health 66 (2003) 519531. [3] R. Bono, E.H. Bugliosi, T. Schiliro`, G. Gilli, The Lagrange Street story: the prevention of aromatics air pollution during the last nine years in a European city, Atmos. Environ. 35 (2001) S107 S113. [4] L. Maestri, S. Ghittori, M. 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