多種抗生素對水體生態食物鏈之 單一及混合效應評估

Abstract

摘要

抗生素除了在農牧業、水產養殖及工業上的使用，也被公認為二十世紀最偉大的醫療發現，本研究選擇三種不同機制且廣泛應用於醫療上的抗生素Oxytetracycline、Erythromycin 及Norfloxacin 並分別以月芽藻、水蚤和羅漢魚進行毒性試驗。物種敏感度結果顯示，月芽藻對於Erythromycin最敏感EC50值為0.08 mg/L而NOEC值為0.03125 mg/L;水蚤在48小時急毒性試驗中對於Norfloxacin最敏感EC50值為56.7 mg/L但是在21天慢毒性試驗中Oxytetracycline的影響反倒是最大的，NOEC值為5 mg/L;羅漢魚對三種抗生素敏感度皆小於上述兩種水生生物。本研究以水蚤測試抗生素兩兩混合之毒性試驗，其中結果Oxytetracycline 和Norfloxacin混合為相加作用，Erythromycin和 Oxytetracycline混合為拮抗作用而Norfloxacin 和 Erythromycin則為協同作用。最後將三個抗生素依測得之最高濃度混合，分別以月芽藻、水蚤和羅漢魚進行試驗，結果顯示沒有生物死亡或抑制情形發生。 在毒性評估方面，本研究使用急毒性及慢毒性試驗結果中最敏感物種之EC50及NOEC數據，以及三種抗生素在環境中測得最高濃度(MECmax)，來求出急毒性及慢毒性之風險評估。結果顯示只有Norfloxacin沒有風險，至於Oxytetracycline和Erythromycin急毒性之風險商數高達46.04及75 mg/L，而慢毒性風險商數則為4.57及1.92 mg/L，對環境危害性大，需要加以管制。

Abstract In addition to the prosperous applications of antibiotics in agriculture livestock industries , aquiculture and industries , the adverse effect of antibioties have receired increasing attention . In this research , we select three different -mechanism antibiotics , which are Oxytetracycline , Erythromycin and Norfloxacin , then do toxicity test on the aquatic organisms , P.subcapitata , D.magna , and P.parva respectively . The results from species sensitivity test show that among different trophic levels , the P.subcapitata has the highest sensitivity to Erythromycin (EC50=0.08 mg/L , NOEC=0.03125 mg/L) . D.magna has the highest sensitivity to Norfloxacin in the 48-hour acute toxicity test (EC50=56.7 mg/L) but is most impacted by Oxytetracycline in the 21-day Chronic toxicity test (NOEC=5 mg/L) . The sensitivities of P.parva to the three antibiotics are all less than the other two aquatilias.In the research , we also apply toxicity test for D.magna with antibiotics making pairs of two in pursuit of the binary effects . Among the results , we have simple addition for combination of Oxytetracycline and Norfloxacin , antagonism for combination of erythromycin and Oxytetracycline , and synergism for combination of Norfloxacin and Erythromycin .

Toxicity test for the aquatic organisms , P.subcapitata , D.magna , and P.parva , with the mixture of three antibiotics (MECmax) displayed no adverse effect or inhibition to P. subcapitata , D.magna and P.parva . For the toxicity assessment , we apply the data from the most sensitive species in acute (EC50) and chronic toxicity (NOEC) with the MECmax of three different antibiotics in the environment to acquire the risk assessment of acute toxicity test and chronic toxicity test . The result shows that Norfloxacin is the only antibiotic without risk . As with Oxytetracycline and Erythromycin , the risk quotient of acute toxicity test is high as 46.04 and 75 mg/L . The risk quotient of chronic toxicity test is 4.57 and 1.92 mg/L . Both of the antibiotics do great harm to the environment , and should be strictly controlled .