2014-01-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/660198摘要：砷是環境中重要的毒性物質且為已知的人類致癌物。尤其是飲用含砷的地下水已造成全球人類健康的隱憂。環境中的無機態砷主要的分為五價的砷酸[As(V) ; HAsO42-]與三價亞砷酸[As(III) ; H2AsO3-]，其中以亞砷酸的溶解度，移動性與毒性較砷酸來的強。越來越多證據顯示微生物於地化條件時，與砷的型態轉移，以及其地質釋放及吸附相當大的關係。其轉移機制包含As(III)的氧化或As(V)的還原，並伴隨著能量生產或解毒的機制。環境中的好氧與厭氧微生物都可能與砷的轉化或循環有關，但這些微生物對於砷的解毒與能量生產機制及在砷循環所扮演的角色卻仍未被徹底了解。臺灣有一些地區的地下水含有極高的砷並曾發生烏腳病的疫情，然而對於臺灣地區地下水系統中微生物對砷的釋放與移動機制的相關研究卻付之闕如。 本研究的目的在於探討台灣烏腳病地區富含砷之沖積含水層中，影響地下水砷之釋放因子及相關機制。研究項目為：(1) 探討微生物和地下水砷釋出的相關性; (2)分離及篩選這些參與生物地化循環作用的微生物; (3) 探討腐植酸、碳源、錳、硫對地下水砷釋出的可能影響; (4) 探討氧氣、肥料中的氮、磷對微生物的群相變化及地下水砷釋出的影響；(5) 探討微生物的群相及厭氧呼吸菌標計基因arrA於不同深度的底泥的變化及分佈; 及(6)本研究欲仿照現地條件驗證砷循環的可行性。 本研究結果將有助於瞭解臺灣地區富含砷水層系統中砷的釋放與移動機制。此外，所分離出的菌及其分子作用機制可能具有用於地下水之生物復育的潛力，並能提供對於台灣地下水的管理策略有價值的資訊。 <br> Abstract: Arsenic poisoning of groundwater used for drinking and irrigation is a global issue. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increasing evidence suggests that the mobilization of arsenic in the environment can be strongly influenced by microbial activity. Although the precise mechanism of arsenic mobilization remains to be characterized in detail, the microbial reduction of sorbed As(V) to the potentially more mobile As(III) has been implicated in release of arsenic into groundwater, but to date there have been few studies of the microorganisms that can mediate this transformation in aquifers. In Taiwan, high arsenic contents of groundwater have been found in several regions. Despite the potential importance of microorganisms in controlling arsenic mobility in the subsurface, there have been no systematic studies of the diversity and activity of these organisms in Taiwan aquifers. The goal of this research is to elucidate factors and mechanisms controlling the release of arsenic in the arsenic contaminated shallow alluvial aquifer in the blackfoot disease endemic area. Proposed specific aims are: (1) Investigating roles of indigenous anaerobic microbes in the arsenic release into groundwater; (2) Identify and isolate microbial populations associated with the distribution of arsenic into groundwater; (3) Identifying factors such as humic acid, carbon sources, manganese and sulfur that might influence arsenic mobilization in the aquifers; (4) Investigating effects of O2 and nitrate and phosphate derived from fertilizer on microbial population and arsenic release; (5) Investigating microbial community structure and abundance of dissimilatory arsenate reduction prokaryotes (DARPs using arrA as marker gene along with well depth in the blackfoot disease area; and finally (6) an arsenic cycle in arsenic contaminated shallow alluvial aquifer will be proposed and validated. Results of this study will elucidate factors and biogeochemical mechanisms controlling the release of arsenic in the arsenic contaminated shallow alluvial aquifer in the blackfoot disease endemic area. Additionally, this study will contribute to the understanding of the microbial ecology of such subsurface communities. Moreover, this study will further provide diagnostic tools for use in the mobilization of arsenic species in natural environments.砷釋出烏腳病地下水微生物生物地化循環作用arsenic releaseblackfoot diseasegroundwatermicroorganismbiogeochemical cycle