臺灣地區由於水資源缺乏，飲用水水源經常取自湖泊與水庫之儲存水體，不過由於山坡地過度開發，大量的氮磷進入湖水中造成湖泊水庫嚴重優養化。微囊藻毒 (microcystins)是優養化湖泊水庫中經常被發現之有毒污染物，近來已被環保署歸類於新興污染物之一。微囊藻毒被證實對人類具肝毒素(hepatotoxins)反應，人類長期飲用含有微囊藻毒的水將增加肝癌、肝腫瘤與腸胃道癌症之風險，因此如何有效去除飲用水之微囊藻毒，成為自來水水質處理之重要課題。目前全世界對微囊藻毒之相關研究集中於流佈調查、分析技術、處理技術與毒理特性，對微囊藻毒在湖泊水庫中之宿命(fate)並不清楚，特別是水體之微觀環境。事實上，湖泊水庫中的微囊藻毒可能與水體中懸浮微粒(膠體顆粒)、溶解性有機物質、富含有機質底泥發生化學傳輸行為。另一方面，微囊藻毒也可能被湖泊水庫中之特定微生物所分解，其分解後產物是否會影響其宿命，優勢微生物種類與數量是否能持續保持，或受到水體中懸浮微粒、溶解性有機酸、底泥有機質影響，進而改變微囊藻毒於湖泊水庫中之傳輸。由這些說明可知化學傳輸行為與微生物分解對湖泊水庫中微囊藻毒宿命之重要性，亦為後續有效去除微囊藻毒所應研究的重要課題。本研究承襲上述研究構想，對湖泊水庫中微囊藻毒之化學傳輸行為與微生物分解作用進行深入的探討。研究共分三年進行，第一年研究為建立微囊藻毒之分析方法及湖泊水庫底泥之表面特性分析，並探討不同微囊藻毒與水體中存在之懸浮微粒、溶解性有機質及土壤有機質對其化學傳輸行為的影響；第二年研究著重於微生物對微囊藻毒之分解，包括篩選與分離可分解微囊藻毒之微生物，分析分解過程之降解速率是否受水體中存在物質之影響，並輔以分子生物技術PCR-DGGE- FISH 方法分析微生物分解過程族群變化；第三年研究則是整合第一年與第二年之研究結果，添加微生物於土壤/水系統與底泥/水系統中進行微囊藻毒之分解，同時考量化學傳輸行為與微生物分解如何影響湖泊水庫中微囊藻毒之宿命。本研究成果將可釐清水體存在之膠體顆粒與底泥有機物質是否影響微囊藻毒之流佈，以提供學理上的證據，並詳細討論其化學傳輸行為與微生物分解之關連性，做為拓展應用微生物控制優氧化湖泊、水庫中微囊藻毒之可行性。 In Taiwan, reservoirs (some lakes) usually are supplied for drinking water. However, industrial and agricultural activities generate serious eutrophication. It allows microcystins detect in most of algae-bloom reservoirs. Microcystins are identified as hepatotoxins to threaten human’s health. People drink water contained low-concentration microcystins for a long time might have the highest cancer risk on liver and gastrointestinal tract. Therefore, how to remove microcystins efficiency in reservoirs becomes an important issue on water supply engineering. Previous researches of microcystins were focus on the distributions in reservoirs and lakes, the improvements of analytical technology, removal technology and the performance of biological toxicity. The fate of microcystins in reservoirs did not research thoroughly, especially in micro-environment sediment/water system. Microcystins might partition on suspended solid in water or the content of organic matter (such as fulvic acid and humin) of sediment. Moreover, many bacteria might biodegrade microcystins. The distribution of microcycsins in reservoirs might be influenced by these microorganisms. Bacterial community and numbers might be changed during biodegradation. The objective of this three-year project is focused on how microcystins on sorption and biodegradation to influence the distribution in the sediment/water systems. The first year of this project is to measure surface characteristics of sediments. The analytical technology of microcystins was established by HPLC. The adsorption equilibrium experiments of different microcystins on water, soil/water and sediment/water systems are processed. The second year of this project is to isolate microorganisms which are able to biodegrade microcystins. Microcystin biodegradations are executed with different content of suspended solid, organic acid, organic matter in water system. The percentage of dominant bacteria during biodegradation is analyzed by molecular biotechnology, PCR-DGGE-FISH. The third year of this project is to combine the experimental results according to previous two years. Experiments are designed as microcystin biodegradation in soil/water and sediment/water systems. The change of bacterial community also is analyzed. The result of this study will provide a good reference for the evaluation of the microcystin removal in eutrophic reservoirs and lakes. The relation of sorption and biodegradation in sediment/water systems will provide good explanations in these mechanisms on the microcystin distribution. 研究期間：9908 ~ 10007
