Buratti M, Pellegrino O, Valla C, Fustinoni S, Colombi A
Istituti Clinici di Perfezionamento, Milano.
Med Lav. 1997 May-Jun;88(3):208-19.
Vehicle exhausts are a well known source of aromatic hydrocarbon pollution in urban environments. The paper reports the results of environmental and biological monitoring of benzene exposure in traffic wardens carried out over a 5-hour workshift. Subjects (n = 131) were grouped according to smoking habits and job task as follows: group (A) 52 nonsmoking office workers, (B) 43 nonsmoking outdoor workers, subdivided into (B1) 36 working on foot and (B2) 7 cyclists; (C) 20 smokers office workers, (D) 16 smokers outdoor workers, subdivided into (D1) 11 working on foot and (D1) 5 cyclists. The median indoor environmental benzene concentration (26 micrograms/m3, n = 50) was significantly lower than the outdoor concentration (45 micrograms/m3, n = 43) (p < 0.01); median exposure value of cyclists was 78 micrograms/m3 (n = 12). For biological monitoring, urinary excretion of trans,transmuconic acid was determined in spot samples collected at 7:30 h (MAit) and 12:30 h (MAft). The MAftA median value (63 micrograms/l, range 2-242 micrograms/l) was not statistically different from MAftB (74 micrograms/l, range 15-216 micrograms/l), while the MAftB2 value of 96 micrograms/l was higher than both MAftB1 (71 micrograms/l) and MAftA. In group (B) there was a relationship between airborne benzene levels and MAftB excretion (y = 17.2 + 1.1x, r = 0.62, n = 35, p < 0.01). The influence of smoking on urinary MA excretion was studied by comparing the results obtained in all nonsmokers (AB) with smokers (CD). MAftCD (192 micrograms/l) was significantly higher than MAftAB (69 micrograms/l) (p < 0.01). In smokers, statistically significant relationships were observed between urinary excretion of MAft (y, microgram/l) and cotinine (x, microgram/l) (y = 83 + 0.08x, r = 0.73, n = 23, p < 0.01), and smoking (x, number cigarettes/day) (y = 87.4 + 4.4x, r = 0.53, n = 29, p < 0.01). Comparison between MAft and MAit median excretion values, calculated for each of the 6 exposure groups, showed that MAft was always higher than the corresponding MAit value. A rough estimate of the total dose of benzene ("index of exposure", EI) inhaled by each subject during the 5-hour working shift as a consequence of air pollution and smoking was also made. Considering the entire group of subjects, a significant association was observed between EI and MAft values (y = 43.4 + 0.39x, r = 0.65, n = 104, p < 0.01). Individual values of MA it were correlated with MAft according to the equation y = 43.6 + 0.82x (r = 0.62, n = 105; p < 0.01) and were also positively associated with EI values (y = 42.3 + 0.20x; r = 0.55; n = 74; p < 0.01). In conclusion, the results suggest that the measurement of urinary MA excretion is a poor indicator for assessing environmental benzene exposure at levels below 100 micrograms/m3, such as those seen in this study; MA can however be reliably used as a biomarker for higher exposures such as those, for example, due to smoking.
汽车尾气是城市环境中芳烃污染的一个众所周知的来源。本文报告了在一个5小时工作班次内对交通协管员苯暴露进行环境和生物监测的结果。根据吸烟习惯和工作任务将受试者（n = 131）分为以下几组：A组52名不吸烟的办公室工作人员；B组43名不吸烟的户外工作人员，再细分为（B1）36名步行工作人员和（B2）7名骑自行车的工作人员；C组20名吸烟的办公室工作人员；D组16名吸烟的户外工作人员，再细分为（D1）11名步行工作人员和（D2）5名骑自行车的工作人员。室内环境苯浓度中位数（26微克/立方米，n = 50）显著低于室外浓度（45微克/立方米，n = 43）（p < 0.01）；骑自行车者的暴露值中位数为78微克/立方米（n = 12）。对于生物监测，在7:30（MAit）和12:30（MAft）采集的即时样本中测定反式、反式粘康酸的尿排泄量。MAftA的中位数（63微克/升，范围2 - 242微克/升）与MAftB（74微克/升，范围15 - 216微克/升）无统计学差异，而MAftB2值96微克/升高于MAftB1（71微克/升）和MAftA。在B组中，空气中苯水平与MAftB排泄量之间存在相关性（y = 17.2 + 1.1x，r = 0.62，n = 35，p < 0.01）。通过比较所有不吸烟者（AB）和吸烟者（CD）的结果研究了吸烟对尿MA排泄的影响。MAftCD（192微克/升）显著高于MAftAB（69微克/升）（p < 0.01）。在吸烟者中，观察到MAft尿排泄量（y，微克/升）与可替宁（x，微克/升）之间存在统计学显著相关性（y = 83 + 0.08x，r = 0.73，n = 23，p < 0.01），以及与吸烟量（x，每天吸烟支数）之间存在相关性（y = 87.4 + 4.4x，r = 0.53，n = 29，p < 0.01）。对6个暴露组中每组计算的MAft和MAit排泄量中位数进行比较，结果显示MAft总是高于相应的MAit值。还对每个受试者在5小时工作班次内因空气污染和吸烟吸入的苯总剂量进行了粗略估计（“暴露指数”，EI）。考虑整个受试者组，观察到EI与MAft值之间存在显著关联（y = 43.4 + 0.39x，r = 0.65，n = 104，p < 0.01）。MAit的个体值与MAft根据方程y = 43.6 + 0.82x相关（r = 0.62，n = 105；p < 0.01），并且也与EI值呈正相关（y = 42.3 + 0.20x；r = 0.55；n = 74；p < 0.01）。总之，结果表明，尿MA排泄量的测量对于评估低于100微克/立方米的环境苯暴露是一个较差的指标，如本研究中所见；然而，MA可可靠地用作更高暴露的生物标志物，例如由于吸烟导致的暴露。
