| 摘要: | 臺灣目前主要以焚化方式處理廢棄物，由鍋爐灰、洗滌灰與集塵灰所收集之飛灰已知含有高量之多氯戴奧辛/呋喃(polychlorodibenzo -p-dioxins and dibenzofurans，PCDD/Fs)，依法規定應進行固化處理，而於處理過程中，勞工可能暴露於PCDD/Fs中，對其健康將造成影響，故應進一步評估，以預防其造成之健康危害。
本研究收集全省飛灰固化廠資料，以營運時間、飛灰量及員工人數作為選廠條件，共選擇7個飛灰固化廠43位勞工，進行血液中17種PCDD/Fs、13項生化及5項荷爾蒙檢測，並以問卷方式調查勞工基本資料(性別、年齡、體重、居住環境…等等)、生活習慣(喝酒、抽菸)、工作史(相關工作、工作習慣、防護具使用…等等)、疾病史、個人飲食習慣，且紀錄勞工工作區域及活動時間。同時，自7個廠中選取A、C、D三廠，分別進行製程區與固化物貯坑/養生區空氣中17種PCDD/Fs檢測分析，最後進行所有數據整合與勞工健康暴露風險評估。
研究結果顯示，在空氣方面：A、C、D廠養生區/固化物貯坑其PCDD/Fs毒性當量濃度分別為0.236、0.085及0.078 pg WHO-TEQ/Nm3；製程區則為0.211、0.086及0.115 pg WHO-TEQ/Nm3。3廠空氣中同源物分布顯示，PCDFs濃度均高於PCDDs，毒性當量濃度又以2,3,4,7,8-PeCDF為主要貢獻同源物。在勞工方面：依據所蒐集勞工之作業內容、工作地點與暴露時間，將43名勞工區分為高、低暴露兩組，其在13項血液生化及5項荷爾蒙檢查異常率均未達到統計上顯著差異；在血液17種PCDD/Fs之平均毒性當量濃度分別為12.3 (6.6~23.9)及8.6 (5.1~12.8) pg WHO98-TEQDF/g lipid，且達統計上顯著差異(p=0.0049)。在高暴露組勞工血液中：2,3,4,7,8-PeCDF、1,2,3,6,7,8 -HxCDF、2,3,4,6,7,8-HxCDF、1,2,3,7,8-PeCDD、1,2,3,6,7,8-HxCDD之毒性當量濃度均顯著高於低暴露組，且具統計上顯著差異(p<0.05)；而在原始濃度部份，血液與空氣同源物分布一致，顯示其血液中濃度受作業環境空氣暴露影響。
進一步解析其他影響因子發現：年齡為影響血液中PCDD/Fs濃度之主要因子之一(P=0.0016)，但經分組之後，在同一年齡層裡，兩暴露組之間並沒有顯著差距(P>0.05)；而在飲食方面：一般食用量及食用頻率較高之高脂肪食物，在兩暴露組之間並無統計上顯著差異，而貝類、牡蠣、優酪乳在本研究中，雖有差異，但一般族群對該等食物之食用量不高，故貢獻量小，應不致影響本研究勞工血液中PCDD/Fs濃度。
綜合解析顯示，空氣暴露雖對勞工血液有所貢獻，但因作業環境空氣中濃度不高，且勞工使用呼吸防護具比例頗高，使得空氣暴露對勞工血液之貢獻量不大。依據風險評估結果顯示，勞工在此作業環境下工作40年仍符合世界衛生組織之終生平均暴露劑量容陪C
Seven fly ash solidification plants and its 43 workers were selected as study subjects. The airborne of PCDD/Fs in the working environment among three plants and serum of workers were collected to measure PCDD/Fs levels. The biochemistry and hormones examinations of 43 workers had been measured. Information obtained from the questionnaire including personal characteristics (sex, age, height, weight, neighborhood geography, etc.), life style (alcohol intake and tobacco usage), occupational history (working histories related to electric arc furnaces, working environment, job titles, working period, and usage of protected equipment, etc.). All the results were integrated to conduct the PCDD/Fs exposure assessment of workers in the fly ash solidification plant.
WHO-TEQ Concentrations of PCDD/Fs of air samples in solidificated product storage area and treatment area of A, C, D plants are 0.236, 0.085, 0.078 pg WHO98-TEQDF /Nm3 and 0.211, 0.086, 0.115 pg WHO98-TEQDF /Nm3 respectively. which are higher than those in ambient air, but lower than those in metal smelting industries. Among 17 PCDD/F congeners, the 2,3,4,7,8-PeCDF were the main congener. High and low exposure groups are divided by the job titles and exposure scenario. The workers who worked in the storage and treatment area were assigned as high exposure group, the maintenance, management workers and the officers were assigned as low exposure groups. Mean and range of TEQ concentrations of PCDD/Fs in serum sample at high and low exposure groups are 12.3 (6.6-23.9) and 8.6 (5.1-12.8) pg WHO98-TEQDF/g lipid, respectively. Significant difference was found between two groups. Higher serum level of 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF, 2,3,4,6,7,8-HxCDF, 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD in the high exposure group were found and the pattern was the same as the air samples. The serum PCDD/F levels were significantly correlated with age.
Higher abnormal rate of cholesterol, triglyceride, albumin, total protein and testosterone were found in both high and low exposure groups. After integrating the congener patterns of serum and airborne PCDD/Fs, the data shows that the serum PCDD/Fs of high exposure group may be affected by the airborne PCDD/Fs of working environment. The usage of personal protective measures was suggested to effectively reduce the concentrations of serum PCDD/Fs in the high exposure workers. It is also suggested that regular health examination of workers should be implemented each year. |
