Monitoring of occupational exposure to tetrachloroethene by analysis for unmetabolized tetrachloroethene in blood and urine in comparison with urinalysis for trichloroacetic acid

Objective: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. Methods: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. Results: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. Conclusions: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA. Received: 11 October 1999 / Accepted: 3 December 1999     

测定尿中三氯乙酸的自动顶空气相色谱法

目的建立尿中三氯乙酸的自动顶空气相色谱测定方法。方法尿中的三氯乙酸加热脱羧生成三氯甲烷,经自动顶空进样器进样,解吸后进气相色谱分离,FID检测,外标法定量。结果三氯乙酸在0.1～100mg/L浓度范围内线性良好(r0.999),最低检出浓度为0.02 mg/L(v=5 ml),方法准确度高,重现性好,样品加标回收率为98.6%～99.7%,相对标准偏差(RSD)为0.8%～2.6%。结论该法简便、灵敏、准确,适用于三氯乙烯接触人群尿三氯乙酸的检测。     

生活饮用水中二氯乙酸和三氯乙酸的离子色谱电导测定法

目的:建立生活饮用水中二氯乙酸(DCAA)和三氯乙酸(TCAA)的离子色谱检测法。方法:利用Dionex 2100型离子色谱仪,选用IonPac AS19阴离子色谱分析柱,进样体积500μl,10 mmol/L～45 mmol/L氢氧化钾溶液梯度淋洗,流速1.0 ml/min,电导检测器,0.22μm滤膜过滤后直接进样。结果:本法相关性r>0.999,DCAA和TCAA最低检出限分别为0.003 mg/L和0.005 mg/L,RSD%<4.56%,回收率范围85%～104%。结论:本法具有简便快速,灵敏准确及安全实用的特点,适合生活饮用水大批样品的检测。     

Measurement of chloral hydrate,trichloroethanol, trichloroacetic acid and monochloroacetic acid in the serum and the urine by gas chromatography

Summary A gas chromatographic method for the determination of trichloroethylene metabolites in the serum and the urine is described.The trichloroethanol glucuronide in the urine was hydrolyzed to trichloroethanol by -glucuronidase. After an extraction with ethyl ether, the extract was dried at 20C, then the residue was extracted with n-hexane and was injected into a gas Chromatograph.Trichloroacetic acid and monochloroacetic acid in the urine were extracted with ethyl ether. After evaporation of the ethyl ether, the acids were methylated with methanolic hydrogen chloride, by heating, and the residue was taken up in n-hexane and was injected into a gas chromatograph. The peak-areas on the gas chromatogram of the trichloroethylene, chloral hydrate and methyl esters of trichloroacetic acid and monochloroacetic acid were measured respectively, using a calibration curve prepared in the same conditions.Procedure for measuring trichloro-compounds in the serum was the same as for that in the urine, except that the ethyl ether extraction of trichloro-compounds was conducted after deproteinization.The serum concentration of trichloro-compounds in the rabbit, after administering trichloroethylene orally, reached the maximum in the following order: trichloroethylene and chloral hydrate > free trichloroethanol, trichloroethanol glucuronide and monochloroacetic acid > trichloroacetic acid. The urinary metabolites of trichloroethylene did so in the following order: free trichloroethanol and monochloroacetic acid > trichloroethanol glucuronide > trichloroacetic acid.Read before the 45th Annual Meeting of Japan Industrial Health Association, Tokyo, April 8, 1972.     

妊娠期三氯乙酸内暴露水平与妊娠结局的关系

目的 调查孕妇妊娠期饮水消毒副产物三氯乙酸(trichloroacetic acid,TCAA))内暴露水平及影响因素,并探讨其与妊娠结局的关系.方法 选择湖北省孝感市某医院2012年11月-2013年3月入院分娩的327名孕妇进行问卷调查,并测定其晨尿中TCAA的含量,采用Logistic回归模型分析探讨妊娠期TCAA内暴露水平和妊娠结局的关系.结果 孕妇尿中TCAA含量的平均值为10.96μg/g cr,P1、P10、P25、P50、P75、P90、P100分别为1.83、3.39、5.20、8.63、12.71、20.19、150.42 μg/g cr.饮水煮沸的孕妇尿TCAA含量明显低于未煮沸者(P＜0.05).经混杂因素校正后,P51～P75的TCAA暴露与胎龄减少有统计学关联(OR=2.947,95％CI:1.504～5.776)；未发现TCAA暴露与新生儿出生体重有关.结论 饮水煮沸可能减少TCAA内暴露水平,妊娠期TCAA暴露可能与早产风险增加有关联.     

小体积水样测定饮用水中二氯乙酸、三氯乙酸的含量

目的优化生活饮用水标准检验方法,建立利用小体积水测定生活饮用水中微量二氯乙酸（DCAA）、三氯乙酸（TCAA）的气相色谱测定方法。方法饮用水中DCAA、TCAA经过酸化、萃取、衍生后,采用气相色谱电子捕获检测器定量检测。结果 DCAA、TCAA在谱图上能够很好的分离,相关系数均大于0.999 5,回收率为94.5%-109.1%,RSD为3.1%-6.5%。结论该方法快速,准确,灵敏度高,适用于生活饮用水的常规批量检测。     

英蓝超滤直接进样离子色谱法测定生活饮用水中的 二氯乙酸、三氯乙酸和草甘膦

摘要:目的　建立生活饮用水中的二氯乙酸、三氯乙酸、草甘膦的英蓝超滤直接进样离子色谱检测方法。方法　生活饮用水经英蓝超滤装置在线过滤后,引入100 μl至离子色谱仪分析,色谱柱:Metrosep A 7-250,淋洗液:7.2 mmol/L碳酸钠溶液,流速:0.8 ml/min。结果　二氯乙酸在0.05 mg/L～1 mg/L,三氯乙酸在0.05 mg/L～1 mg/L,草甘膦在0.5 mg/L～2 mg/L线性关系良好,线性相关系数r＝0.991～0.999,加标回收率在73%～121%,相对标准偏差（RSD%）在2.6%～13.5%。方法检出限:二氯乙酸0.01 mg/L,三氯乙酸0.03 mg/L,草甘膦0.03 mg/L。结论　本方法操作简单、不污染环境、对操作人员无危害、适合批量检测生活饮用水中的二氯乙酸、三氯乙酸和草甘膦。     

三氯乙酸对L-02细胞DNA甲基化转移酶1蛋白及mRNA表达的影响

目的探讨三氯乙酸(TCA)染毒对L-02细胞DNA甲基化转移酶1(DNMT1)蛋白及mRNA表达的影响。方法取处于对数生长期的正常肝细胞(L-02细胞),分别加入含0(对照)、0.1、0.3、0.9 mmo/L TCA的培养液继续培养24、48、72 h,同时,设DNA甲基化酶抑制剂5-氮杂胞苷(5-aza-d C,5μmol/L)处理组,TCA-re组(0.9 mmol/L TCA处理后换正常培养基继续培养24 h)和人肝癌(HepG2)细胞组作为对照。检测细胞DNMT1蛋白和mRNA的表达水平。结果与对照组比较,各浓度TCA染毒组及5-aza-d C处理组、TCA-re组L-02细胞DNMT1 mRNA的表达水平均较低,而HepG2细胞组DNMT1 mRNA的表达水平较高,差异均有统计学意义(P0.05)。与相同剂量TCA染毒24 h比较,各浓度TCA染毒48、72 h后L-02细胞DNMT1 mRNA的表达水平均较低,除0.1、0.9 mmol/L TCA染毒48 h外,差异均有统计学意义(P0.05)。且随着TCA染毒浓度的升高和染毒时间的延长,L-02细胞DNMT1 mRNA的表达水平均呈下降趋势。与0.9 mmol/L TCA染毒组比较,TCA-re组L-02细胞DNMT1 mRNA的表达水平较高,差异有统计学意义(P0.05)。与对照组比较,各浓度TCA染毒组及5-aza-d C处理组L-02细胞DNMT1蛋白的表达水平均较低,除0.1 mmol/L TCA染毒24、48 h及0.3mmol/L TCA染毒24 h外,差异均有统计学意义(P0.05);而TCA-re组L-02细胞和HepG2细胞组DNMT1蛋白的表达水平均无明显变化。与相同剂量TCA染毒24 h比较,各浓度TCA染毒48、72 h后L-02细胞DNMT1蛋白的表达水平均较低,差异均有统计学意义(P0.05)。除TCA染毒24 h时L-02细胞DNMT1蛋白的表达水平随染毒浓度的升高而呈先升高后下降的趋势外,随着TCA染毒浓度的升高和染毒时间的延长,L-02细胞DNMT1蛋白的表达水平均呈下降趋势。与0.9 mmol/L TCA染毒组比较,TCA-re组L-02细胞DNMT1蛋白表达水平较高,差异有统计学意义(P0.05)。结论 TCA体外染毒可能通过抑制DNMT1的表达维持或者促进细胞的DNA低甲基化状态。     

Simple microdetermination of trichloroethanol glucuronide and trichloroacetic acid in urine

Summary A microdetermination of estimating urinary trichloroethanol glucuronide and trichloroacetic acid is described. The glucuronide of trichloroethanol in urine was hydrolysed and oxidized to trichloroacetic acid by chromium trioxide. Trichloroacetic acid thus produced was allowed to react with pyridine and potassium hydroxide in a boiling water bath, and the product was treated with benzidine dihydrochloride or less toxic p-toluidine hydrochloride. In the urine containing trichloroethanol glucuronide and trichloroacetic acid, total trichloro-compound was obtained after oxidation to trichloroacetic acid. The assay of trichloroacetic acid is identical with the above except that digestion step was omitted. And the difference between the two results was considered to estimate the trichloroethanol content.The analytical sensitivity of this reaction is about 4 times as much as the pyridine potassium hydroxide reaction. Direct microdetermination for urinary trichloroacetic acid is also estimated.     

Urinary trichloroacetic acid levels and semen quality: A hospital-based cross-sectional study in Wuhan, China

Toxicological studies indicate an association between exposure to disinfection by-products (DBPs) and impaired male reproductive health in animals. However, epidemiological evidence in humans is still limited. We conducted a hospital-based cross-sectional study to investigate the effect of exposure to DBPs on semen quality in humans. Between May 2008 and July 2008, we recruited 418 male partners in sub-fertile couples seeking infertility medical instruction or assisted reproduction services from the Tongji Hospital in Wuhan, China. Major semen parameters analyzed included sperm concentration, motility, and morphology. Exposure to DBPs was estimated by their urinary creatinine-adjusted trichloroacetic (TCAA) concentrations that were measured with the gas chromatography/electron capture detection method. We used linear regression to assess the relationship between exposure to DBPs and semen quality. According to the World Health Organization criteria (<20 million/mL for sperm concentration and <50% motile for sperm motility) and threshold value recommended by Guzick (<9% for sperm morphology), there were 265 men with all parameters at or above the reference values, 33 men below the reference sperm concentration, 151 men below the reference sperm motility, and 6 men below the reference sperm morphology. The mean (median) urinary creatinine-adjusted TCAA concentration was 9.2 (5.1) μg/g creatinine. Linear regression analyses indicated no significant association of sperm concentration, sperm count, and sperm morphology with urinary TCAA levels. Compared with those in the lowest quartile of creatinine-adjusted urinary TCAA concentrations, subjects in the second and third quartiles had a decrease of 5.1% (95% CI: 0.6%, 9.7%) and 4.7% (95% CI: 0.2%, 9.2%) in percent motility, respectively. However, these associations were not significant after adjustment for age, abstinence time, and smoking status. The present study provides suggestive but inconclusive evidence of the relationship between decreased sperm motility and increased urinary TCAA levels. The effect of exposure to DBPs on human male reproductive health in Chinese populations still warrants further investigations.     

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.     

生活饮用水中二氯乙酸三氯乙酸检测方法的改进

目的改进和优化生活饮用水中二氯乙酸三氯乙酸气相色谱检测方法。方法样品在酸性条件下萃取,再经衍生反应,采用恒温方式毛细管色谱柱分离、ECD检测器气相色谱法测定,内标法定量。结果经改进后的方法通过提高衍生温度为60℃,衍生时间缩短为90min,柱温恒温为90cC,二氯乙酸、三氯乙酸出峰时间缩短。二氯乙酸、三氯乙酸在0-1001xg／L具有良好的线性,相关系数〉0．999,相对标准偏差RSD2．9％～8．8％,回收率为86％一95．4％。结论通过改进优化样品萃取、衍生及色谱条件,缩短了检测时间,减少了试剂的用量。大大提高了工作效率、节约了检测成本,有利于大批水样的分析测定。     

A time-saving procedure for the determination of total trichloro-compounds in human urine samples

Summary A modification (Tanaka and Ikeda, 1968) of the original method of Seto and Schultze (1956) has been further improved, by utilizing the heat in a boiling water bath for both the oxidation and colour development. As a result the determination of total trichloro-compounds in human urine could be carried out within 1 hr.This work was supported in part by a research grant from the Fujiwara Memorial Foundation.     

Determination of thiodiglycolic acid in urine specimens of vinyl chloride exposed workers

Summary A strong correlation was found between vinyl chloride concentrations at working places and the increased excretion of thiodiglycolic acid of 18 exposed workers. The mean air concentration of vinyl chloride was calculated referring to personal exposure. The values obtained were in the range of 0,14–7,0 ppm. The excretion of thiodiglycolic acid — measured by GC-MS analysis — amounted to 0,3 – 4,0 mg/L. It could be demonstrated that significant increases of the metabolite excretion occur even at VC-concentrations below 5 ppm.