以空氣與尿液樣本測定石化廠作業勞工苯暴露

Exposure Measurements of Benzene by Using Air and Urine Samples for Workers in Petrochemical Factories

江玲蓁(Jiang Ling-Jhen)

指導教授 ： 吳俊德

長榮大學/健康科學學院/職業安全與衛生學系(所)/碩士(2014年)

https://doi.org/10.6833/CJCU.2014.00197

摘要

本研究以五個石化廠作業勞工為研究對象，實施苯暴露個人空氣與尿液樣本測定，主要研究目的為：(1)描繪作業勞工苯暴露實態；(2)評估以作業勞工尿液苯暴露測定估計內部暴露劑量的可行性；(3)探討個人外在暴露濃度與內部暴露劑量的關聯性。研究中對每一個石化廠作業勞工依其所屬部門、製程、作業項目、製程所使用或產生的苯環類有機化合物暴露劃分相似暴露群組(similar exposure group, SEG)，並於每一個SEG進行隨機抽樣選取測定對象。樣本採樣於正常工作時段內，請勞工配戴個人採樣泵搭配熱脫附管(填充Tenax TA吸附劑)，採集勞工呼吸區帶空氣樣本。並於在勞工上工前、午休時間以及下班前，收集勞工尿液樣本，實施尿液中苯的生物指標物測定，包括：t,t-muconic acid (t,t-MA)和S-phenylmercapturic acid (S-PMA)。於樣本收集同時，給予勞工一份工作紀錄表，調查勞工個人基本資料及紀錄作業勞工一天工作內每15分鐘所參與的工作項目，探究其暴露影響因子。本研究空氣樣本的苯測定以熱脫附儀儀器(PerkinElmer TurboMatrix ATD-350)搭配火焰離子化偵測器氣相層析儀(Agilent-6890)進行分析；尿液樣本以頂空氣體進樣搭配氣相層析質譜儀分析苯本體及以高效能液相層析儀串聯質譜儀(high performance liquid chromatograph-tandem mass spectrometry, LC-MS/MS)測定 t,t-MA和S-PMA含量。本研究一共獲得564個個人空氣中苯濃度採樣測定及254人次的尿液樣本，估計8小時時量平均暴露測定濃度平均值(標準差)為5.49(18.89) ppb，遠低於法定容許濃度；計算各SEG勞工暴露實態分佈的95%分位值超過法定容許暴露濃度的機率小於5%，顯示勞工苯暴露風險極低。針對186位不抽菸勞工，執行勞工個人空氣8小時時量平均暴露濃度與尿液苯本體濃度的線性迴歸分析，結果顯示空氣中的苯暴露濃度分別與中午的尿液苯本體和下午的尿中代謝物t,t-MA呈現高度正相關(R= 0.91，p值<0.05 和 R= 0.97，p值<0.05)。不抽菸勞工尿液中苯代謝物t,t-MA和S-PMA的含量平均值(標準差)分別為173.04(655.74) μg/gCr和0.22(1.67) μg/gCr，t,t-MA含量與空氣8小時時量平均暴露濃度呈現統計上顯著相關性。因此結論在低濃度空氣苯暴露時，中午和下工後的尿液苯本體與t,t-MA比苯代謝物S-PMA是較為靈敏的暴露偵測指標物。

關鍵字

苯暴露 ； 石化廠 ； 空氣暴露測定 ； 生物偵測指標物 ； 尿中苯

並列摘要

This study conducted continuous pesonal air monitoring of benzene and measured urine samples for operations workers in five petrochemical factories. The objectives of this study are: (1) to describe the actual state of benzene exposure in operation workers; and (2) to estimate in internal exposure dose of feasibility in the operation workers exposed to benzene in urine determination of assessment; and (3) to explore individual external exposure concentration and internal exposure dose relationship. The workers were divided into several similar exposure groups (SEGs) for benzene-ring compounds exposure (including benzene, toluene, o-xylene, p-xylene and m-xylene, styrene and ethylbenzene) according to the departments, processes, wrok tasks they joined. Exposure measurements were taken for the workers randomly selected from each SEG during regular workdays. Each selected worker was asked to wear a personal sampling pump equipped with a thermal desorption tube containing Tenax TA sorbent. The worker’s breathing zone air was drawn into the thermal desorption tube to collect the benzene-ring compounds. Urine samples were collected by workers at three time points, pre-shift, lunch break and post-shift, to determine benzene exposure biomarkers including t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA). During the exposure samples collection time, each measured worker was asked to fill a job record sheet to invstigate his demographical information and record the work tasks he involved in each 15 minutes during the work day to explore the determinants of personal benzene exposure. The air samples were analyzed by thermal desorption instrument with a gas chromatograph flame ionization detector to quantify the amount of benzene. The urine samples were analyzed by headspace gas chromatography with mass spectrometry (HS-GC/MS) method to measure the amount of benzene. A high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) system was used to measure the amounts of t,t-MA and S-PMA. A total of 564 personal exposure measurements and 254 urine samples were collected in this study. The estimated mean (standard deviation) of 8-hour time-weighted average exposure (8-hr TWA) concentrations of benzene was 5.49(18.89) ppb. This mean value was far below the permissible exposure limit of benzene. The probability of the 95th percentiles of exposure profile of all the SEGs exceeding the benzene permissible exposure limit was less than 5%. This showed that the workrs of the petrochemical factories could result in extremely low benzene exposure risk. A linear regression analysis was performed for the 8-hr TWAs and urinary benzene concentrations. The results showed that positive high correlations (r=0.91, p-value <0.05 and r=0.97, p-value <0.05) between the airborne benzene exposure concentrations and the urinary benzene concentrations at lunch break and the amounts of t,t-MA at post-shift. For the non-smoking workers, the means (standard deviation) of t,t-MA and S-PMA were 173.04(655.74) and 0.22(1.67) μg/gCr. The levels of t,t-MA was statistically correlated with the the airborne benzene exposure concentrations in the workers. We concluded that at low concentration benzene exposure, the concentration of benzene at noon urine samples and the amount of t,t-MA at post-shift urine samples were more sensitive exposure markers than that of S-PMA.

並列關鍵字

petrochemical factory ； benzene exposure ； urinary benzene

參考文獻

American Conference of Governmental Industrial Hygienists (ACGIH) (2013) Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati (OH), ACGIH.

Barbieri A, Violante FS, Sabatini L, Graziosi F, Mattioli S. (2008) Urinary biomarkers and low-level environmental benzene concentration: assessing occupational and general exposure, Chemosphere. 74(1):64-69.

Bergamaschi E, Brustolin A, De Palma G, Manini P, Mozzoni P, Andreoli R, Cavazzini S, Mutti A. (1999) Biomarkers of dose and susceptibility in cyclists exposed to monoaromatic hydrocarbons. Toxicol Lett. 1999 Sep 5;108(2-3):241-247.

Boogaard PJ, van Sittert NJ. (1995) Biological monitoring of exposure to benzene: a comparison between S-phenylmercapturic acid, trans,trans-muconic acid, and phenol, Occup Environ Med. 52(9):611-620.

Boogaard, P.J., Van, Sittert, N.J. (1996) Suitability of S-phenyl mercapturic acid and trans-trans-muconic acid as biomarkers for exposure to low concentrations of benzene,”Environmental Health Perspectives, 104:1151-1157.