苯,甲苯,二甲苯暴露人群遗传毒性生物标志物的研究

为研究苯系物职业接触人群的生物标志物，应用高效液相色谱－电化学检测系统（ＨＰＬＣ－ＥＣ）分析８７名苯接触工人及３０名对照人群外周血淋巴细胞８－羟基－２－脱氧鸟苷（８－ＯＨｄＧ），同时检测工人个体接触空气苯浓度及尿粘康酸（ＴＴＭＡ）、外周血淋巴细胞微核（ＭＮ）及白细胞（ＷＢＣ）值。结果显示：外周血淋巴细胞８－ＯＨｄＧ、ＭＮ、尿ＴＴＭＡ在苯接触人群增高显著，８－ＯＨｄＧ与空气苯、尿ＴＴＭＡ存在良好相关，且８－ＯＨｄＧ与ＭＮ之间存在一定相关性。结果提示：苯可诱导职业接触人群ＤＮＡ氧化损伤，苯的遗传毒性机理可能是通过多位点、多作用机理、多遗传后果所致。８－ＯＨｄＧ可作为苯系物职业接触人群的生物标志物，影响苯接触人群外周血淋巴细胞８－ＯＨｄＧ形成的因素有性别和甲苯。     

某大型石化企业职业人群混苯暴露水平监测

「目的」通过测定某大型石化企业车间环境中混苯（苯、甲苯、二甲苯）及工人尿液中混苯的代谢产物,评价工人的接触水平。「方法」选择该公司有混苯暴露的芳烃等六个厂以无混苯暴露的职工医院,用气相色谱法（ＧＣ）测定空气中混苯,并用高效液相色谱法（ＨＰＬＣ）法测定工人尿液中反,反－粘糠酸（ｔ,ｔ－ＭＡ）以及马尿酸（ＨＡ）。「结果」车间空气中苯的平均浓度波动在０．７３～２６．９１ｍｇ／ｍ＾３之间,阳大超标率为７．４１％,最大超标倍数为２０．９１;混苯暴露厂工人尿液中ｔ,ｔ－ＭＡ,工后明显高于工前,差值波动在１．１４～３．７８μｇ／ｍｇ．Ｃｒ,明显高于对照单位的０．３３μｇ／ｍｇ．Ｃｒ,且暴露工人尿液的变化值与空气苯浓度呈等级相关性（Ｒｓ＝０．６４,Ｐ＝０．０３）;甲苯、二甲苯检出率较低,ＨＡ工后、工前无明显差异。「结论」该公司     

尿粘康酸在苯的生物监测中的应用价值

为研究苯暴露的生物标志物，应用改进的高压液相色谱法检测了１２８名苯接触工人及４０名对照人群的尿粘康酸含量，同时测定了其尿酚含量。结果表明，当空气苯浓度为４１．４９ｍｇ／ｍ３时，接触工人的尿粘康酸含量为（５．４７±７．９４）ｍｇ／ｇＣｒ，尿酚为（３９．０９±４２．５９）ｍｇ／ｇＣｒ。对照人群的尿粘康酸含量为（０．１３±０．０９）ｍｇ／ｇＣｒ，尿酚为（１６．０１±１１．３３）ｍｇ／ｇＣｒ（均为肌酐校正值，ｘＧ±ｓ）。苯接触工人的尿粘康酸含量与所接触的空气苯浓度及尿酚含量呈良好的相关，相关系数分别为０．９１８７，０．８２０４。尿粘康酸在人群中本底值低，反映苯的内吸收情况比尿酚更特异、敏感，更适于低浓度苯暴露的生物监测。     

丙烯腈尿中代谢物—腈乙基巯基尿酸的测定

建立了柱前荧光衍生—高效液相色谱法测定丙烯腈（ＡＣＮ）在人尿中的代谢物—Ｓ－２－腈乙基巯基尿酸［Ｎ－乙酰－Ｓ－２－腈乙基半胱氨酸（ＣＥＭＡ）］。尿中ＣＥＭＡ的酸性水解产物Ｓ－２－羧乙基半胱氨酸（ＣＥＣ）与邻苯二甲醛反应生成强荧光物质。该衍生物经Ｃ１８柱分离后，用荧光检测器检测。方法检测限为３μｍｏｌ／Ｌ，尿中ＣＥＭＡ浓度为５０、２００μｍｏｌ／Ｌ时批内平均相对标准偏差为２．９％，尿加标平均回收率为９４％。ＡＣＮ现场工人的尿样经高效液相色谱—质谱联机（ＨＰＬＣ—ＭＳ）分离鉴定，确证尿中巯基尿酸结构为ＣＥＭＡ。正常人尿中未检出该化合物。该方法应用于３４例ＡＣＮ现场工人尿中ＣＥＭＡ的测定，浓度范围在３～３１６７μｍｏｌ／Ｌ     

尿粘康酸作为苯内接触剂量的应用

为将尿粘康酸（ＴＴＭＡ）应用于苯接触人群的检测，应用高效液相色谱－紫外检测器系统检测苯接触人群尿ＴＴＭＡ。结果显示，尿ＴＴＭＡ在苯接触人群中有显著增加，随着空气苯浓度的增加，尿ＴＴＭＡ增加显著，显示出良好的相关关系（ｒ＝０．９４０，Ｐ＜０．０５）。当苯接触浓度为均值２．４６２ｍｇ／ｍ３时，接触人群尿ＴＴＭＡ与对照组相比，其差异具有统计学意义。提示，尿ＴＴＭＡ可作为苯接触特异、灵敏的生物检测指标，尤其对于低苯接触。尿ＴＴＭＡ在男女苯接触人群中差异无显著性。甲苯可抑制尿ＴＴＭＡ的形成。应用协方差分析可粗略校正甲苯的混杂作用。     

苯接触的生物监测指标初步评估

目的：探索可客观反映职业性苯危害的灵敏指标。方法：测定苯作业车间空气苯浓度和３３名苯作业工人及４名非苯作业工人志愿者苯接触后呼出苯浓度、血苯含量及尿酚排出量，并进行相关性分析。结果：空气苯浓度（４．５～３４８ｍｇ／ｍ３）与血苯含量呈明显正相关（Ｐ＜０．０５）；血苯含量与尿酚排出量呈非常显著正相关（Ｐ＜０．０１）。结论：在低浓度苯接触时，血苯是一个与毒性相关联的特异性敏感苯吸收指标；尿酚排出量可用作高浓度苯接触工人的生物监测指标。     

苯作业工人癌症队列研究Ⅱ

为阐明苯的多发致癌性及其剂量－反应关系，在原１２城市调查基础上扩大队列，并将随访期从１９８１年延长至１９８７年，共调查苯作业工人７４８２８人，对照工人３５８０５人，合计达１２０万人年。共搜集空气苯浓度评价数据１８４３５个。结果表明：苯组白血病、骨髓增生异常综合征（ＭＤＳ）及淋巴瘤发病危险度均显著升高，其中急性髓细胞白血病（ＡＭＬ）的相对危险度（ＲＲ）为３．１，淋巴瘤为３．５；ＡＭＬ、ＡＭＬ与ＭＤＳ和淋巴瘤随累积接苯量增加而升高，呈明显剂量－反应关系。苯接触男工肺癌死亡ＲＲ也显著升高并呈剂量－反应关系。引发肿瘤升高的苯浓度约为３．３ｍｇｍ－３／ａ。     

苯的生物监测方法及进展

本文主要综述了近年来苯的生物监测及进展情况。研究表明尿酚及呼出气中苯不适于作接触低浓度苯的生物监测指标。尿中的ｔ，ｔ－己二烯二酸与Ｓ－苯基巯基尿酸则可作为接触低浓度苯的监测指标。     

职业性苯中毒早期生物监测指标筛选探讨

为探讨职业苯中毒的早期监测指标，本实验室对低于国家卫生标准的二个不同浓度下职业苯接触组的人群，测定了白细胞脂流动性（Ｌ）．白细胞和血清丙二醛（ＭＤＡ），血清超氧化物歧化酶（ＳＯＤ），丙氨酸转氨酶（ＡＬＴ），硷性磷酸酶（ＡＫＰ）等生化指标以及白细胞（ＷＢＣ），血小板（Ｐｔ）计算，血红蛋白（Ｈｂ）含量等传统指标，部分工人检测了尿液反，反－粘康酸（ｔ，ｔ－ＭＡ）含量，结果，接触组的ＷＢＣ计数较对照组明显     

生物法制备苯的代谢物—S—苯巯基尿酸

生物法制备苯的代谢物—Ｓ－苯巯基尿酸李晓华李春玲吴宜群Ｓ－苯巯基尿酸（Ｓ－ＰＭＡ）是国际上新研究的低水平苯接触的生物标志物之一，但其标准品尚无商品供应。我们以大鼠作为载体，用生物法［１］制备了Ｓ－ＰＭＡ。一、原理在动物体内苯的主要代谢物中，酚约占吸收...     

苯的两种生物标志物现场应用价值的比较

选择了８６名苯接触工人进行现场研究。结果表明当空气苯浓度的几何均值为３１．８６ｍｇ／ｍ３时，代谢物粘康酸的几何均值为３．１５３ｍｇ／ｇ，尿酚则为３１．０２７ｍｇ／ｇ。接触的空气苯浓度分别与代谢物粘康酸和尿酚之间的相关系数为０．９０１２、０．７３０１。接触低浓度苯的人群尿酚与外接触的苯水平相关性较差；但粘康酸无论是在接触高的或低的苯浓度情况下，二者之间均有良好的相关性。粘康酸在对照组检出水平极低。提示：粘康酸可替代尿酚作为苯的生物学监测指标     

Urinary t,t-muconic acid as an indicator of exposure to benzene

A method for rapidly determining t,t-muconic acid (MA) by high performance liquid chromatography was developed and successfully applied to urine samples from 152 workers exposed to benzene (64 men, 88 women) and 213 non-exposed controls (113 men, 100 women). The MA concentrations in urine correlated linearly with time weighted average benzene concentrations in the breath zone air of workers. A cross sectional balance study showed that about 2% of benzene inhaled is excreted into the urine as MA. The MA concentrations in the urine of the non-exposed was below the detection limit (less than 0.1 mg/l) in most cases, and the 95% lower confidence limit of MA for those exposed to benzene at 5 ppm (5.0 mg/l as a non-corrected value) was higher than the 97.5%-tile values for the non-exposed (1.4 mg/l). In practice, it was possible to separate those exposed to 6-7 ppm benzene from the non-exposed by means of urine analysis for MA. The urinary MA concentration was suppressed by coexposure to toluene.     

Urinary t,t-muconic acid as an indicator of exposure to benzene.

A method for rapidly determining t,t-muconic acid (MA) by high performance liquid chromatography was developed and successfully applied to urine samples from 152 workers exposed to benzene (64 men, 88 women) and 213 non-exposed controls (113 men, 100 women). The MA concentrations in urine correlated linearly with time weighted average benzene concentrations in the breath zone air of workers. A cross sectional balance study showed that about 2% of benzene inhaled is excreted into the urine as MA. The MA concentrations in the urine of the non-exposed was below the detection limit (less than 0.1 mg/l) in most cases, and the 95% lower confidence limit of MA for those exposed to benzene at 5 ppm (5.0 mg/l as a non-corrected value) was higher than the 97.5%-tile values for the non-exposed (1.4 mg/l). In practice, it was possible to separate those exposed to 6-7 ppm benzene from the non-exposed by means of urine analysis for MA. The urinary MA concentration was suppressed by coexposure to toluene.     

Evaluation of occupational exposure to benzene by urinalysis

Urinary phenol determinations have traditionally been used to monitor high levels of occupational benzene exposure. However, urinary phenol cannot be used to monitor low-level exposures. New biological indexes for exposure to low levels of benzene are thus needed. The aim of this study was to investigate the relations between exposure to benzene (Abenzene, ppm), as measured by personal air sampling, and the excretion of benzene (U-benzene, ng/l),trans,trans-muconic acid (MA, mg/g creatinine), andS-phenylmercapturic acid (PMA, g/g creatinine) in urine. The subjects of the study were 145 workers exposed to benzene in a chemical plant. The geometric mean exposure level was 0.1 ppm (geometric standard deviation = 4.16). After logarithmic transformation of the data the following linear regressions were found: log (U-benzene, ng/l) = 0.681 log (A-benzene ppm) + 4.018; log (MA, mg/g creatinine) = 0.429 log (A-benzen ppm) – 0.304; and log (PMA, g/g creatinine) = 0.712 log (A-benzene ppm) + 1.664. The correlation coefficients were, respectively, 0.66, 0.58, and 0.74. On the basis of the equations it was possible to establish tentative biological limit values corresponding to the respective occupational exposure limit values. In conclusion, the concentrations of benzene, mercapturic acid, and muconic acid in urine proved to be good parameters for monitoring low benzene exposure at the workplace.     

职业性苯暴露反-反式粘糠酸生物接触限值研究

目的研究职业性苯暴露反．反式粘糠酸（t,t—MA）生物接触限值。方法实验室建立生产环境空气中苯浓度的气相色谱检测方法及作业工人尿中t,t—MA含量的高效液相色谱检测方法,并通过检测苯暴露现场工人8h苯暴露水平及班前、班后尿中t,t．MA含量,研究其相关性。结果苯暴露者班前、班后尿中t,t—MA含量与其苯暴露水平有明显的相关关系。班前y（mg／gCr）=0．924＋0．108X（me／m^3）,r=0．62,P〈0．01;班后y（mg／gCr）=2．103＋0．177X（mg／m^3）,r=0．791,P〈0．01。结论根据我国作业场所空气中苯的国家卫生标准,按回归方程推导出职业接触苯生物接触限值,推荐职业暴露苯的生物接触限值为工作班班后尿t,t．MA含量为3．0mg／gCr,下一班班前尿t,t．MA含量为1．5mg／gGr。     

Urinary phenylmercapturic acid as a marker of occupational exposure to benzene

A hand-saving HPLC method to measure urinary phenylmercapturic acid (PMA) was developed which allows about 35 PMA determinations per day. The method involves conversion of pre-PMA to PMA by the addition of sulfuric acid to a urine sample, extraction into an ether-methanol mixture followed by condensation under a nitrogen stream. The condensate was introduced to a ODS-3 column in a HPLC system, and PMA in the column was eluted into a mobile phase of acetonitrile: methanol: perchloric acid: water. The elution of PMA was monitored at 205 nm. One determination will be completed in 40 min. The method was applied to analysis of end-of-shift urine samples from 152 workers exposed up to 210 ppm benzene, 66 workers exposed to a mixture of benzene (up to 116 ppm) and toluene + xylenes (up to 118 ppm), and 131 non-exposed controls of both sexes. A linear regression was established between time-weighted average intensity of exposure to benzene and urinary PMA. From the regression, it was calculated that urinary PMA level will be about 6.4 mg/l after 8-hour exposure to benzene at 100 ppm, and that PMA in urine accounted for about 0.1% of benzene absorbed. No effects of sex, age, and smoking habit of individuals were detected, and the effect of co-exposure to toluene + xylenes at the levels comparable to that of benzene was essentially nil, which indicates an advantage of PMA as a benzene exposure marker over monoto tri-phenolic metabolites or t,t-muconic acid.     

Aromatic and polycyclic hydrocarbons in air and their urinary metabolites in coke plant workers

This study describes the exposure of coke plant workers to hydrocarbons. Aromatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) in the breathing zone air and their oxygenated metabolites in the urine of coke plant workers are qualitatively and quantitatively determined. Concentrations of benzene, toluene, naphthalene, m+p-xylene, o-xylene and 14 different PAHs were measured at the different workplaces by personal air sampling. O-cresol, 1- and 2-naphthol, methylhippuric acid, and 1-hydroxypyrene were determined in hydrolyzed urine of workers collected after the work shift. The gas chromatography–mass spectrometry (GC/MS) method was applied to identify AHs in air and in urine samples. Time-weighted values of exposure to aromatic hydrocarbons at a coke plant were: benzene (0.06–9.82 mg/m³), toluene (0.05–4.71 mg/m³), naphthalene (0.01–3.28 mg/m³), o-xylene (0.01–1.76 mg/m³) and m + p-xylene (0.01–2.62 mg/m³). At the coke batteries, the total concentration of PAHs ranged from 7.27 to 21.92 μg/m³. At the sorting department, the total concentration of PAHs were about half this value. Concentration of the urinary metabolites (naphthols and methylhippuric acid) detected in workers at the tar distillation department are three times higher than those for the coke batteries and sorting department workers. A correlation between inhaled toluene, naphthalene, xylene, and urinary excretion of metabolites has been found. Time-weighted average concentrations of AHs in the breathing zone air show that exposure levels of the workers are rather low in comparison to exposure limits. The 1-hydroxypyrene concentration is below 24.75 μmol/mol creatinine. The GC/MS analysis reveals the presence of AHs, mainly benzene and naphthalene homologues. It has been found that coke plant workers are simultaneously exposed to the mixture of aromatic and polycyclic hydrocarbons present in the breathing zone air of a coke plant. Exposure levels are significantly influenced by job categories. Compounds identified in the urine appear to be the products of the hydroxylation of AHs present in the air as well as unmetabolized hydrocarbons. Am. J. Ind. Med. 34:445–454, 1998. © 1998 Wiley-Liss, Inc.     

Concentrations of benzene in blood and S-phenylmercapturic and t,t-muconic acid in urine in car mechanics

Summary Different parameters of biological monitoring were applied to 26 benzene-exposed car mechanics. Twenty car mechanics worked in a work environment with probably high benzene exposures (exposed workers); six car mechanics primarily involved in work organization were classified as non-exposed. The maximum air benzene concentration at the work places of exposed mechanics was 13 mg/m³ (mean 2.6 mg/m³). Elevated benzene exposure was associated with job tasks involving work on fuel injections, petrol tanks, cylinder blocks, gasoline pipes, fuel filters, fuel pumps and valves. The mean blood benzene level in the exposed workers was 3.3 g/l (range 0.7–13.6 g/1). Phenol proved to be an inadequate monitoring parameter within the exposure ranges investigated. The muconic and S-phenylmercapturic acid concentrations in urine showed a marked increase during the work shift. Both also showed significant correlations with benzene concentrations in air or in blood. The best correlations between the benzene air level and the mercapturic and muconic acid concentrations in urine were found at the end of the work shift (phenylmercapturic acid concentration: r = 0.81, P < 0.0001; muconic acid concentration: r = 0.54, P < 0.05). In conclusion, the concentrations of benzene in blood and mercapturic and muconic acid in urine proved to be good parameters for monitoring benzene exposure at the workplace even at benzene air levels below the current exposure limits. Today working as a car mechanic seems to be one of the occupations typically associated with benzene exposure.     

Lack of correlation between environmental or biological indicators of benzene exposure at parts per billion levels and micronuclei induction

Despite growing concern for possible carcinogenic effects associated with environmental benzene exposure in the general population, few studies exist at parts per billion (ppb) levels. We investigated the existence of a relationship between airborne/biological measurements of benzene exposure (i.e., personal/area sampling and unmodified urinary benzene/trans,trans-muconic acid; t,t-MA) and micronuclei induction (cytochalasin B technique) among exposed chemical laboratory workers (n=47) and traffic wardens (n=15). Although urinary t,t-MA (106.9+/-123.17 microg/L(urine)) correlated (R(2)=0.37) with urinary benzene (0.66+/-0.99 microg/L(urine)), neither biological measurement correlated with environmental benzene exposure (14.04+/-9.71 microg/m(3); 4.39+/-3.03ppb), suggesting that, at ppb level (1ppb=3.2 microg/m(3)), airborne benzene constitutes a fraction of the total intake. Traffic wardens and laboratory workers had comparable numbers of micronuclei (4.70+/-2.63 versus 5.76+/-3.11; n.s.), similar to levels recorded in the general population. With univariate/multivariate analysis, no association was found between micronuclei induction and air/urinary benzene exposure variables. Notably, among the personal characteristics examined (including age, gender, smoking, drinking, etc.), high body mass index correlated with micronuclei induction while, among females, use of hormonal medication was associated with less micronuclei. Thus the present study provides no evidence that ppb levels of environmental benzene exposure appreciably affect micronuclei incidence (against the background of other relevant factors). However, this should not be taken as an argument against efforts aiming to reduce environmental benzene pollution.     

Biological monitoring of vehicle mechanics and other workers exposed to low concentrations of benzene

 It has been suggested that the threshold limit value (TLV) for the time-weighted average (TWA), of benzene be lowered because of its possible leukemogenic effect at low exposure concentrations. This requires the development of new methods of biological monitoring. In this cross-sectional study the diagnostic power of blood and breath benzene and of urinary phenol, catechol, hydroquinone, S-phenylmercapturic acid, and muconic acid were compared in a population of 410 male workers exposed to benzene in garages, in two coke plants, and in a by-product plant. Benzene exposure was assessed by personal air sampling (charcoal tube and passive dosimeter). In all, 95% of the workers were exposed to less than 0.5 ppm benzene. According to the multiple regression equation, the muconic acid and S-phenylmercapturic acid concentrations detected in nonsmokers exposed to 0.5 ppm benzene were 0.3 mg/g and 6 μg/g, respectively (range 0.2–0.6 mg/g and 1.2–8.5 μg/g, respectively). With muconic acid very few false-positive test results were found, and this determination remained reliable even around a cutoff level of 0.1 ppm benzene. Moreover, the diagnostic power of this test proved to be good even when diluted or concentrated urine samples were not excluded. S-Phenylmercapturic acid (S-PMA) also performed fairly well. Blood and breath benzene as well as urinary phenol (PH) and hydroquinone (HQ) were clearly less suitable biomarkers than muconic acid (MA). Catechol (CA) was not associated with occupational benzene exposure. According to the results of biological monitoring, the skin resorption of benzene from gasoline or other fuels seems negligible. Correlation, multiple regression, and likelihood ratios consistently showed that MA and S-PMA concentrations were fairly good indicators of benzene exposure in the 0.1- to 1-ppm range, even in a population comprising both smokers and nonsmokers. PH, HQ, CA, and blood and breath benzene were less suitable, if at all, in the same exposure range. Received: 31 July 1996/Accepted: 29 November 1996