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標題: | 除蟲菊精類殺蟲劑芬化利與其他四種殺菌劑對端足蟲 (Hyalella azteca) 之混合毒性效應 The joint effects of pyrethroids fenvalerate and four other fungicides on Hyalella azteca |
作者: | Yi-Ting Chao 趙怡婷 |
指導教授: | 顏瑞泓 |
關鍵字: | 端足蟲 (amphipods),人工合成除蟲菊酯 (pyrethroids),芬化利 (fenvalerate),協同係數 (synergistic ration),解毒酵素 (detoxification enzyme),酯? (esterase), Amphipods,Pyrethroids,Fenvalerate,Synergistic ration,Detoxification enzyme,Esterase, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 農業生產過程中為確保作物品質與產量,種植期間經常施用兩種以上的農藥,農藥最終無可避免地會進入環境水體中。而底泥為環境汙染物淤積匯聚的場所,以底棲非目標生物進行底泥毒性試驗為評估農藥環境風險的重要方法之一。本研究使用底棲生物端足蟲Hyalella azteca作為指標生物,與台灣河川中檢出頻度高的五種藥劑:殺蟲劑益達胺 (imidacloprid)、芬化利 (fenvalerate)、殺菌劑撲克拉 (prochloraz)、菲克利 (hexaconazole) 和待克利 (difenoconazole),及各國地下水經常檢出之除草劑草脫淨 (atrazine),進行7天之急毒性試驗。試驗結果發現芬化利對端足蟲毒性遠大於其他五種藥劑,其半數致死濃度 (50% lethal concentration, LC50) 為16.7 ng L-1。
由前人研究發現除蟲菊精類殺蟲劑對端足蟲的毒性遠大於其他藥劑,與端足蟲同為水生生物的魚類亦有相同的趨勢,目前研究認為除蟲菊精類殺蟲劑對魚類之高毒性來自其酯酶 (esterase) 活性較其他動物 (如哺乳類) 低,本研究將端足蟲暴露於芬化利中7天並檢測其酯酶萃取液酵素活性表現。與前人研究比較後發現對照組端足蟲酯酶之最大催化速率Vmax小於青鱂魚、裂尾魚、鮭魚與豬隻來源之酯酶萃取液,且暴露於芬化利濃度2及10 ng L-1中酯酶活性表現有下降趨勢並存在劑量效應。 已知酯酶為生物體內重要解毒酵素,於是進一步探究在酯酶活性表現受芬化利影響的情況下,是否會增加其他藥劑對端足蟲的毒性。選擇四種殺菌劑撲克拉、待克利、依普同 (iprodione) 與撲滅寧 (procymidone) 與低濃度芬化利進行混合毒性試驗,測量端足蟲暴露於混合藥劑7天之LC50。試驗結果發現添加芬化利濃度1及2 ng L-1,撲克拉LC50由0.25分別降至0.05及0.04 mg L-1、待克利由0.32降至0.02 mg L-1、依普同由6.30分別降至3.97與5.58 mg L-1。顯示存在低濃度芬化利的情況下,確實會增加殺菌劑撲克拉、待克利與依普同的毒性。而撲滅寧處理組於不同芬化利濃度處理下,其LC50無顯著差異。本研究發現存在低濃度芬化利時,可能增加部分殺菌劑對底泥毒性指標生物端足蟲的毒性,未來於環境中施用芬化利時應進行更審慎的評估。 To ensure the production and the quality of crops, the application of pesticides is necessary during agricultural activities. The fate of these sprayed compounds would inevitably enter the aquatic system. Hence, the sediment becomes the sink of pollutants. Acute toxicity test of non-target organisms are an important way to assess the environmental risk of pesticides. In this study, amphipods Hyalella azteca was selected as test organism to evaluate the toxicity of six pesticides. There are five commonly used pesticides in Taiwan: imidacloprid, fenvalerate, prochloraz, hexaconazole and difenoconazole, and including a frequently detected herbicide atrazine in ground water. The result showed that fenvalerate is the most toxic compound toward H. azteca during the 7 d acute toxicity test, demonstrating a 50% of lethal concentration (LC50) is 16.7 ng L-1. Compared with previous research, pyrethroids are more toxic to H. azteca than other types of pesticides. Some fish species are as sensitive as H. azteca to pyrethroids because of the slow metabolic rate of parent compound. Esterase is the main metabolic enzyme of pyrethroids in vivo. In this research, esterase was extracted from H.azteca. The maximum velocity of esterase (Vmax) was compared with other animals in literature. We found that the Vmax of H. azteca esterase extractions is slower than those from medaka, splittail, salmon and porcine. After 7d exposed to the fenvalerate, the esterase activity in H. azteca decreases with the increasing concentration of fenvalerate. It is known that esterase is an important detoxification enzyme in vivo. As the esterase can be inhibited by fenvalerate, the addition of other pesticides may exert higher toxicity to non-target organisms. Four fungicides: prochloraz, difenoconazole, iprodione and procymidone were selected and mixed with fenvalerate to exam the joint effect on H. azteca in 7d acute toxicity test. The results showed that under 1 and 2 ng L-1 fenvalerate, the LC50 of prochloraz is decreased from 0.25 to 0.05 and 0.04 mg L-1 respectively. Difenoconazole is decreased from 0.21 to 0.02 mg L-1. Iprodione is decrease from 6.32 to 3.97 and 5.58 mg L-1. The fenvalerate treatment with procymidone make no significant different in LC50 under 95% confident interval. This research indicated that under low concentrations of fenvalerate, the toxicity of other fungicides would be increased. Thus, when applying pyrethroids, we should consider the synergic toxicity effects of more than one pesticide rather than merely singular toxicity effects toward non-target organisms. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/50490 |
DOI: | 10.6342/NTU201601381 |
全文授權: | 有償授權 |
顯示於系所單位: | 農業化學系 |
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