Albendazole (ABZ)為一常見的苯並咪唑類驅蟲藥劑，其有較高的Kow 值(辛醇-水分配係數)及Koc值(有機碳-水分配係數)，對有機相親和力強，故容易累積於土壤及底泥。由於人們過去長期以來的使用已使得ABZ進入到自然環境當中，然而目前已有許多文獻指出ABZ具有生物毒性，若持續殘留在環境裡將可能影響其它非標的生物與衍生出抗藥性問題。二氧化錳(MnO2)為土壤/底泥常見的天然礦物，具有強氧化能力且能參與多種有機汙染物之氧化降解。根據MnO2及ABZ之特性，可推測MnO2很可能會參與ABZ在環境當中的轉化，本研究旨在瞭解MnO2對於ABZ之氧化降解機制與轉化途徑，此將有助於釐清其在環境中的行為與宿命。

研究結果顯示，離子強度及金屬離子對於ABZ之降解速率並無明顯影響，而酸性條件卻有利於ABZ之轉化；有機共溶劑之存在則會抑制反應進行，由於ABZ對於有機溶劑之親和力較強，減少其對於MnO2表面之接觸機會使得反應速率變慢，且隨使用的有機溶劑極性愈低，對於ABZ降解的阻礙效果愈強(抑制能力：乙醚 ~ 正丁醇 > 乙醇 > 甲醇 > 乙腈)；實驗發現也腐植酸會造成MnO2之還原溶解，故對反應亦具有明顯的抑制效果。由反應動力學模擬結果得知，表面複合物之形成(吸附步驟)在MnO2對ABZ的降解中為控制反應速率的主要因子。

以高效能液相層析串聯質譜儀(LC-MS/MS)檢測後發現，ABZ結構上的丙硫基(propylthio group)為MnO2主要的氧化位置，形成之氧化降解產物為albendazole sulfoxide (ABZ-SO)。此外，若將ABZ溶解於純水中，ABZ會水解成多種水解產物，而這些水解產物亦會與MnO2反應，形成更多樣的氧化衍生物，這些衍生化合物相較ABZ具有較高的極性，於環境中的流動性較高，然而產物鑑定結果卻顯示水解及氧化反應難以破壞其主體結構，故這些衍生物仍可能具有生物毒性並對環境具有潛在威脅。

Albendazole (ABZ) is a benzimidazole-based veterinary anthelmintic used extensively in the treatment of intestinal parasites. Due to its high hydrophobicity, ABZ tends to accumulate in soils and sediments in the environment. This study aims to investigate ABZ’s possible degradation by manganese oxides. Minor effects from ionic strength and metal cations on ABZ degradation were observed. By contrast, decrease of pH greatly enhanced the reaction rate. Surface complexation between ABZ and MnO2 was indicated to be the dominant control in the reaction kinetics. The water solubility of ABZ could be enhanced by the existence of co-solvents, which subsequently decreased the affinity of ABZ to MnO2 surface. Suppression by the presence of co-solvents was negatively proportional to the solvent polarities (suppression from high to low: diethyl ether～n-butanol > ethanol > methanol > acetonitrile). Humic acid was found to cause significant inhibition due to the reductive dissolution of MnO2. Four hydrolysis and six oxidative products were identified in this study. Substitutions occurred on both the methyl carbamate and propylthio side chains, yielding the hydrolysis products. The sulfur atom on the propylthio group was confirmed as the major oxidative site. ABZ and its hydrolysis products containing the propylthio side chain underwent the same oxidative transformation to form their corresponding sulfoxide compounds. Dehydrogenative coupling reaction between sulfoxide products and hydrolysis products could occur to generate dimers. All hydrolysis and oxidative products were eluted faster than ABZ in liquid chromatogram, suggesting that these products are more polar compounds and that the spreading out of ABZ will be significantly enhanced if reacting with MnO2 in the environment.

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