| 摘要: | 烷基酚聚乙氧基醇類化合物(alkylphenol polyethoxylates, APEOs)是從1940年起被廣泛使用的一種人造非離子型界面活性劑。這類界面活性劑經使用後，排放至水環境中後會被水中微生物降解成下列幾種代謝物：(a)烷基酚(alkylphenols, AP)、短鏈式烷基酚聚乙氧基醇類代謝物(shortened ethoxy chain APEO residues)；或是(b)短鏈式烷基酚聚乙氧基羧酸類代謝物(alkylphenol polyethoxy carboxylates, APECs)、烷基酚聚乙氧基雙羧酸類代謝物(carboxyalkyl phenoxy ethoxy carboxylates, CAPECs)。然而，上述的這些代謝物由於具有荷爾蒙效應與不易被降解之持久性質，加上烷基酚聚乙氧基醇類持續使用，這些物質已引起科學家興趣，而不斷持續的研究與檢測。台灣地區，由於壬基酚聚乙氧基醇類(nonylphenol polyethoxylates)非離子型界面活性劑被大量生產與使用，對於缺乏都市與工業用廢水處理廠的台灣地區，大量含有壬基酚聚乙氧基醇類的污水將會被直接地排放入河川中，進而對河川生態造成影響。因此，針對烷基酚聚乙氧基醇類代謝物對生態上可能造成的傷害，本論文將開發有效的分析方法以檢測台灣地區環境中的烷基酚聚乙氧基醇類代謝物之殘留濃度。在本研究中，主要是利用兩種前處理方法結合氣相層析質譜儀進行烷基酚聚乙氧基醇類代謝物的定性與定量分析。在水樣方面，採取固相萃取法(solid-phase extraction)萃取並濃縮水樣中烷基酚聚乙氧基醇類代謝物。在固態樣本方面，則是採用蒸汽蒸餾萃取法(steam distillation extraction)萃取固態樣本中烷基酚聚乙氧基醇類代謝物。這些檢測方法經由本研究證實，不但具有良好的再現性與絕佳的回收率，而可有效檢測烷基酚聚乙氧基醇類代謝物於不同基質環境樣本中的殘留濃度。 本研究的架構，首先針對可能的排放源頭：家用清潔劑中壬基酚聚乙氧基醇類的濃度進行調查。在2002年台灣地區抽樣檢驗的90種市售家用清潔劑商品中，有高達41%的產品有添加壬基酚聚乙氧基醇類，產品的添加濃度範圍介於0.2到21%之間。由於台灣地區壬基酚聚乙氧基醇類被廣泛使用在清潔劑商品中，因此可預期在城市和工業區等地區，將會將含有烷基酚聚乙氧基醇類的廢水直接排放入河川中造成台灣地區水環境的衝擊。基於上述的原因，為能夠瞭解各種的烷基酚聚乙氧基醇類代謝物在河水中之分佈情形，本論文接著著手研究台灣地區的18條主要河川所含此類代謝物之殘留濃度分佈情形。在所有檢測河水樣品中，最常被檢驗出與最高殘留濃度的烷基酚聚乙氧基醇類代謝物皆為烷基酚聚乙氧基雙羧酸類代謝物 (CAPECs)。但因缺乏CAPEC類代謝物標準品，在研究此類代謝物的相關文獻中並不能完整評估萃取回收率、偵測極限與衍生化產率等的研究，導致烷基酚聚乙氧基雙羧酸類代謝物在水樣中的殘留濃度不能準確地被評估。因此在本研究中，將合成烷基酚聚乙氧基雙羧酸類代謝物部分標準品（在本文中縮寫為CA4P1EC），以進行定性定量的分析。而實驗結果也證明合成之CA4P1EC標準品成功應用在檢測水樣中CA4P1EC之殘留濃度中，檢測殘留濃度範圍介於n.d.至3.24 μg/L之間。 烷基酚在沿海地區殘留濃度的資料可以當作沿海水域的污染指標，而可聯繫沿海地區與附近連接河川間的污染程度，進而查出可能之烷基酚的污染來源。但是在台灣沿海地區關於烷基酚於水樣和生物體中殘留濃度資料是缺乏的。根據本論文研究顯示，台灣沿海地區的海產養殖作物（牡蠣與蚵螺）已經受到烷基酚的污染，其中辛基酚(4-tOP)的濃度介於70 – 820 ng/g (乾重)，壬基酚(4-NPs)的濃度則介於210 – 2750 ng/g (乾重)。藉由上述實驗，接著針對牡蠣、蚵螺、台灣西部沿海地區的水樣與底泥調查烷基酚在台灣地區的累積與分佈情形。結果發現高濃度的烷基酚廣泛存在於所有檢測基質中，並且進一步發現累積在牡蠣和蚵螺樣本體內之烷基酚的組成比例和濃度會隨著季節的變化產生不同變異。同時也發現，隨著季節變化，像是經由成長、生物轉化作用和新陳代謝所造成的生理變動，將可能會改變烷基酚於生物體內累積效應的強弱。 在本論文中，可以觀察到高濃度的烷基酚聚乙氧基醇類之相關代謝物廣泛分佈並累積在台灣地區的環境中。雖然在2006年台灣地區已公告列管烷基酚聚乙氧基醇的使用，但由於此類相關代謝物對於台灣地區生物具潛在荷爾蒙效應風險，在此建議政府有關單位應以逐步減少使用至完全禁止烷基酚聚乙氧基醇這一類非離子型界面活性劑在商業或工業上的使用，以杜絕此類代謝物在環境上的危害。 Widespread environmental contamination by persistent organic pollutants (POPs) is not a new problem. Polychlorinated biphenyls (PCBs), DDT, organic heavy-metal compounds and polycyclic aromatic hydrocarbons (PAHs) are well-known historically. Current contamination involves, for example, pharmaceuticals and endocrine disruptors. Alkylphenol polyethoxylates (APEOs), one of the most important classes of nonionic surfactants, were introduced in the 1940s. APEOs in wastewater are biodegraded into (a) alkylphenols (APs) or shortened ethoxy chain APEO residues (such as AP1EO) and (b) alkylphenol polyethoxy carboxylates (APECs) or carboxyalkylphenoxy ethoxy carboxylates (CAPECs). These metabolites of APEOs are of interest in the field of environmental monitoring because of the volume of these substances used and their activity as either endocrine disruptors or as persistent pollutants. However, nonylphenol polyethoxylates (NPEOs) are mass-produced and used widely in Taiwan. Large quantities of these surfactants in wastewater are discharged into the rivers directly because Taiwan’s municipal and industrial wastewater treatment facilities are deficient. The source, occurrence and fate of metabolites of APEOs are all unclear and can potentially affect the aquatic environment of Taiwan. Analytical methods must be developed for effectively identifying trace-levels of metabolites of APEOs in Taiwan’s environment since they exhibit estrogenic activities and toxicities. In this study, the analytical methods combined with gas chromatography-mass spectrometry (GC-MS) were developed to identify metabolites of APEOs in the environmental samples. Solid-phase extraction (SPE) procedures were developed and the application of metabolites of APEOs in water samples was evaluated. The metabolites of APEOs in solid samples were extracted using steam distillation extraction (SDE) with n-hexane. These approaches are highly reproducible and provide excellent recoveries. They have been successfully applied to analyze the metabolites of APEOs in various sample matrices. Firstly, the content of NPEOs in various household detergents sold in Taiwan were investigated. The results demonstrate that NPEOs were detected in 41% of 90 household detergents at concentrations from 0.2 to 21%. Since APEOs are used extensively in cleaners, the rivers of Taiwan receive large quantities of APEOs in wastewaters directly from the cities, industrial parks and suburban areas. Therefore, the concentrations of metabolites of NPEOs were analyzed in the river water samples to determine the distribution characteristics of these persistent alkylphenolic compounds in 18 major rivers of Taiwan. The CAPEC residues were detected most frequently and at the highest concentrations (as compared to other metabolites of NPEOs) in all river water samples. However, the extraction recoveries, detection limits and derivatization yields of CAPEC residues have not been completely estimated in previous studies because of a lack of authentic standards for CAPECs. Hence, CAPECs have three or four carbon atoms and a carboxyl group in the alkyl chain side, and a carboxymethoxy acid group in their para-position (expressed as CA3P1EC and CA4P1EC in their abbreviation) were synthesized. In this work, the synthesized CA4P1EC was successfully applied to determine more accurately the concentrations of CA4P1EC residues in the water samples. The concentrations of CA4P1EC residues were also detected in the aquatic environment from n.d. to 3.24 μg/L. Secondly, the presence of APs near the coast of Taiwan was investigated because data on the concentration of APs in estuary water and the tissues of marine organisms in Taiwan are scarce. This information is valuable in locating possible sources of contamination with APs. Preliminary results indicated that APs are ubiquitous in oysters (Crassostrea gigas) and snails (Thais clavigera, T. rufotincta, T. keluo) along the coast of Taiwan and the concentrations of 4-t-OP and 4-NPs ranged from 70 to 820 ng/g and from 210 to 2750 ng/g (dry weight), respectively. The distribution of APs in oysters (C. gigas), snails (T. clavigera), coastal water and coastal sediments near the western coast of southern Taiwan were examined. APs were present in all matrices of interest and the bioaccumulation of APs resulted in a seasonal variation in their compositions and concentrations in oyster and snail samples. Serious contamination with metabolites of APEOs is widespread in Taiwan. This study provides information about the presence and fate of persistent metabolites of APEOs in the environment of Taiwan, in support of environmental protection programs. The appropriate action is to ban or restrict the use of APEOs in commercial or industrial applications because the metabolites of APEOs are potentially estrogenically dangerous to the environment of Taiwan. |
