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年度	109	專案性質	實驗性質
專案類別	研究專案	研究主題	調查
申請機構	中央大學	申請系所	環工所
專案主持人	林居慶	職等/職稱	副教授
專案中文名稱	商業有機肥料與沼渣沼液作為環境抗生素抗藥性發展的潛在來源探究
中文關鍵字	有機肥料, 沼渣沼液, 抗生素抗藥性, 環境來源
專案英文名稱	Commercially available organic fertilizers and anaerobic digestion residues as potential sources of antibiotic resistome development in the environment
英文關鍵字	Organic fertilizers, anaerobic digestion residues, antibiotic resistome, environmental sources
執行金額	1,070,000元
執行期間	2020/1/1 至 2020/12/31
計畫中文摘要	抗生素自發現後已廣泛應用在醫療及畜牧養殖產業(主要為添加至飼料)，但隨著抗生素的濫用及糞肥的農地施用，抗生素抗性基因(ARGs)在環境的背景濃度逐漸升高，其後果將可能嚴重威脅現代醫學的成就，引起許多國際衛生組織的關注。過往的文獻已指出相較於堆肥，傳統經由中、常溫厭氧消化方式處理後的禽畜糞便，其所含的ARG濃度無法被有效削減，某種程度暗示如要推動畜牧糞尿經厭氧消化處理後的沼液沼渣作為農地肥分的使用時，應先審慎調查評估並排除是否會因此而導致施作土壤環境的抗藥性增長的問題。有鑑於此，本計畫針對市售的堆肥以及畜牧場的沼液沼渣進行有系統的抗生素抗藥性分析，藉此了解何種來源(如豬糞、牛糞、雞糞以及非糞便類別的廢棄物等)與何種程序(好氧堆肥、厭氧消化)所得的有機肥料具有相對較高的抗藥性發展及累積潛勢；此外，也進行堆肥及沼渣沼液添加的短期(一個月)土壤縮模試驗，以了解國內新舊型態肥料中的ARGs在土壤環境的增殖與降解宿命。檢測的結果與當初的預期相符，即本期計畫於夏季所採集的27件沼液沼渣樣品，其內所含不論是ARG或是整合子基因的相對豐度，皆顯著高於28件堆肥樣品；不僅如此，沼液沼渣組別中豬糞高於牛糞，堆肥組別中非禽畜糞低於於任何禽畜糞樣品(包括雞糞、豬糞、牛糞與混合糞肥)。由於本研究所檢測的樣品數量足以代表一般常見的現況，說明禽畜糞便的確是促成環境抗藥性增長的關鍵因素，值得注意。更甚者，本計畫所分析的沼液沼渣已屬亞熱帶地區戶外溫度較高的情況下所得的樣品，但在這樣的厭氧處理條件下依舊無法表現出優於堆肥程序的抗藥性削減效率，代表其他季節所產出的沼液沼渣更是需要檢視其抗藥性程度(即ARG濃度以及抗性菌密度與組成)，以完整掌握此管道所造成的環境抗藥性發展潛勢。最後，利用乾淨穰土所進行的短期土壤縮模培養試驗結果顯示，添加兩種肥料的土壤內ARG與整合子基因相對豐度的減少程度，整體而言與無添加肥料的土壤對照組相當；此外，大部分組別的基因豐度減少程度約略在一個層級，且降解後的豐度含量仍高於對照組，說明如果在此實驗條件下的沼液沼渣施肥一個月內再次澆灌的話，將有可能造成ARGs的累積。由於這樣的實驗設計僅只實驗室的模擬試驗，確切的環境抗藥性宿命仍須藉由實際接受沼液沼渣的農地土壤採樣、分析，才能準確說明現況。即使如此，本研究初步調查的結果某種程度仍可闡述禽畜糞肥內的抗藥性在土壤介質的變化。
計畫英文摘要	Antibiotic resistance is accelerating at a very scary rate, as evidenced by the fact that “the 10-year-grace-period” for resistance to develop has been shortened to be within a year, and the potential threat level can be equivalent to climate change according to WHO. This is mainly attributed to the misuse of antibiotics at an alarming rate, particularly in agricultural activities. While application of organic fertilizers derived from animal manure including the anaerobic digestate in farmland is considered one of the routes that leads to the development of antibiotic resistance in the environment, little has been undertaken in Taiwan. This is of concern, because many studies have shown that mesophilic anaerobic digestion fails to reduce the levels of antibiotic resistance genes (ARGs) as compared to composting and thermophilic anaerobic digestion. Here, 27 digestate samples from anaerobic digestion systems of both cow and pig farms from Hsinchu to Yunlin were collected and determined the abundance of ARGs. Twenty-eight commercially available compost samples were also purchased and processed with the same analyses. Results showed that relative abundance of the tested ARGs was higher in digestate samples than in compost samples, implying that application of digestate as fertilizers may impose a higher potential of antibiotic resistance proliferation in farmland soils, as compared with composts. In addition, we observed that composts prepared from biomass wastes exclusive of manures contained lower ARG abundance than manured composts. To probe the fate of ARGs in agricultural soil, microcosm experiments were conducted using clean loam-type soil excavated from a pristine area in the Shimen Reservoir, spiked with digestate or composts and incubated for a month. Soils with no fertilizers were used as controls. Results showed that ARGs in fertilized soils declined to the same extent as in control soils, indicating that repeating irrigation of digestates within a month may lead to accumulation of ARGs in soils. If the policy of reuse of animal excretions continues to implement, we suggest that the application of biochar materials in farmland soil in a way similar to active capping used for sediment remediation may improve the limitation of ARG proliferation in the agricultural area.