不同材質家戶用水設備釋出壬基酚及雙酚A之探討

Abstract

環境荷爾蒙已被證實會造成生育力下降、雄性動物雌性化等影響到自然生態的不良作用。在眾多的環境荷爾蒙中又以雌素酮 (Estrone, E1)、天然動情激素 (17β-estradiol, E2)、乙炔動情激素 (17α-ethynylestradiol, EE2)、雌素醇 (Estriol, E3)、壬基酚 (Nonylphenol, NP)、辛基酚 (Octylphenol, OP)、雙酚A (Bisphenol A, BPA)等為最受重視的內分泌干擾素。許多研究指出環境中以NP和BPA的濃度較高、檢出率較大，因此本研究針對NP及BPA加以探討。 目前對於NP和BPA的環境流佈研究大多關注於河川、汙水處理廠放流水、淨水廠出水等水體，或是著重於食品包裝上，例如瓶裝水、奶瓶等。而從其它的研究中可知淨水場處理流程可有效降解水中NP及BPA，但在家戶用水中仍可偵測到這些物質。臺灣目前從淨水廠到使用點的輸水管線仍有使用PVC材質，許多房齡十幾年的建築同樣使用PVC管做為配水管線。由於有研究指出PVC會釋出NP和BPA，因此淨水廠出水流經這些管線後可能造成水中此兩種物質的濃度再次上升，但少有人注意到水管管線材質的影響。 本研究選取三種不同材質之水瓶(玻璃、不銹鋼、塑膠)放置於室溫下模擬NP和BPA釋出，另外探討不同溫度的影響。在家戶採樣部分，考慮台灣地區家戶最常使用的管線材質，分別選取臺灣北部、南部使用PVC、不鏽鋼、鍍鋅鋼管為配水管材的家戶做為研究對象，進行每三個月一次的採樣，以了解不同材質的管線是否會影響水中NP及BPA的濃度；同時探討不同季節不同氣溫中，溫度的變化是否也會影響NP及BPA釋出濃度。此外，為了更清楚的瞭解PVC管釋放出NP和BPA的趨勢，本研究亦將將飲用水裝入PVC管做模擬測試，以驗證PVC管材是否釋出此兩種物質。 研究結果發現裝於玻璃瓶和不銹鋼瓶中的NP濃度分別為103.0和94.7 ng/L，接近Milli-Q水中的濃度 (99.06±12.25 ng/L)，而在塑膠瓶中濃度則較前兩者為高 (147.97±27.99 ng/L)，當塑膠瓶之環境溫度升高至45℃時，NP濃度也隨之上升 (203.1±15.14 ng/L)。在模擬管材試驗的部分，PVC管中NP和BPA濃度會隨放置時間增長使釋出濃度隨之增加，而在不銹鋼管中NP和BPA濃度只些微增加，除此之外濃度還受到外界氣溫變化的影響而有所改變。在家戶採樣部分，使用PVC管線的住宅的飲用水，不管是南部或北部，水中NP濃度都較使用不銹鋼管線的住宅來得高 (PVC: 63.59-195.15 ng/L; stainless steel: 22.90-43.75 ng/L)，BPA部分則是只有北部P-2、P-3和南部P-2有量測到，且都為使用PVC管線的家戶，其餘則是低於偵測極限 (＜1.73 ng/L)。根據本研究中採樣之家戶水中NP和BPA濃度為基準計算之健康風險顯示，自來水中的NP和BPA濃度對人體不致造成不良健康效應。 依本研究結果，建議以不銹鋼材質的管材作為家戶輸水管線，較能避免水中NP和BPA濃度因管材釋出而升高進而暴露到較高濃度的NP或BPA。為了去除水中的污染物而選用淨水器時，則應挑選包含活性碳過濾裝置的淨水器較能去除NP和BPA。在研究限制部分，管材間的差異性、家戶建築的樓高和氣候因素均可能對實驗結果造成影響。

Endocrine disruption chemicals (EDCs) have been reported to affect reproduction, feminization, and other adverse effects. The main EDCs include estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), estriol (E3), nonylphenol (NP), octylphenol (OP), bisphenol A (BPA). There are many literatures reveal that NP and BPA have been detected with high detection rates and levels in various waters. The concerns about occurrences of NP and BPA mostly focus on their distribution over environmental waters, such as river, effluents from sewage treatment plants (STPs) and treated water from water treatment plants (WTPs). Food packaging materials are sources of NP and BPA, such as bottled water, baby bottle and so on. Reports have been shown that STPs and WTPs treatment process can degrade NP and BPA effectively, but these compounds also can be observed in tap water. The materials of pipeline from WTPs to household facilities, such as PVC, can be a source of NP and BPA in tap water. Previously studies have revealed that NP and BPA can be released from PVC, so the concentrations of NP and BPA in the distribution systems can be increased. There is only little information available concerning the effects of household pipeline materials on NP and BPA concentrations in tap water. In study, bottles with different materials were chosen for assessment of NP and BPA releases: glass, stainless steel and plastic. Effects of temperatures were also studied. In household pipeline material, three piping materials were chosen for field study: PVC, stainless steel and galvanized piping, these materials are widely used in households in Taiwan. Water samples were collected from selected households in Taipei and Kaohsiung at different seasons to elucidate the effects of the pipeline material and temperature on the levels of NP and BPA in tap water. In order to confirm that NP and BPA can release from PVC pipes, Milli-Q and tap water were sealed in PVC and stainless steel pipes to simulate the trends of NP and BPA releasing from pipes. The results showed that, at room temperature (25℃), NP concentrations in glass (103.0 ng/L) and stainless steel bottles (94.7 ng/L) were closed to those in Milli-Q water (99.06±12.25 ng/L); however, the NP concentration (147.97±27.99 ng/L) in plastic bottles was higher than those in glass and steel bottles. When temperature rises (45℃), NP concentrations also rises (203.1±15.14 ng/L), too. In simulated pipe material tests, the NP and BPA concentrations in PVC pipe will increase as contact time increase; for stainless steel material, the NP and BPA concentrations only increase with a small amount. The results also showed that weather will affect the concentrations of NP and BPA. In household piping lines, the NP in households using PVC pipes were generally higher than those using stainless steel pipes (PVC: 63.59-195.15 ng/L; stainless steel: 22.90-43.75 ng/L); and BPA were only detected in P-2, P-3 in the northern Taiwan and P-2 household in the southern Taiwan, which all use PVC pipes, and other households were under the limit of detection for BPA (＜1.73 ng/L). The risk assessments of human exposures to NP and BPA based on the concentrations of NP and BPA in household tap water showed that exposures to NP and BPA in household water will not cause apparent adverse health effects. Stainless steel pipe is advised to be used as household water pipes which can protect residents from exposing to higher NP or BPA. For control of these containments from tap water with water purifiers, the results of this study showed that activated carbon adsorption provides suitable treatment efficiencies for NP and BPA removals. However, the heterogeneous compositions of pipe material, the heights of selected buildings and the weather conditions are factors which can affect the results of this study.