三種人類常用抗生素之環境風險評估

Abstract

抗生素是人類最常用的藥物之一，在水體環境檢測出的頻率相當高，因此需要評估是否會對生態環境造成危害。本研究選擇三種在台灣河川中偵測濃度高的抗生素：lincomycin、suflamethoxazole和flumequine，使用月芽藻和水蚤進行單一毒性試驗。抗生素對月芽藻的毒性由高至低為lincomycin > flumequine > sulfamethoxazole，而對水蚤則是sulfamethoxazole > flumequine > lincomycin。根據歐洲藥物管理局制定的準則，對抗生素進行初步環境風險評估。預測無效應濃度之計算使用本研究月芽藻以及文獻中最敏感物種的急慢毒性數據。使用月芽藻EC50計算的lincomycin的風險商數為1.82，而用低NOEC計算的sulfamethoxazole之風險商數為1.102，表示具有潛在環境風險。本研究以月芽藻測試抗生素兩兩混合之毒性效應，發現lincomycin和sulfamethoxazole混合產生簡單相加作用，其餘兩組混合則為拮抗作用。考慮最壞情況，將三個抗生素依測得最高濃度混合，分別以月芽藻、水蚤和鯉魚進行試驗，結果顯示沒有生物死亡或抑制情形發生。

Antibiotics are one of the most widely used pharmaceuticals and can be frequently detected in aquatic environment. Therefore, it is necessary to evaluate the potential risks of antibiotics to the environment. Lincomycin, sulfamethoxazole and flumequine are three antibiotics found in Taiwan’s river with considerably high concentrations. Based on toxicity tests using Pseudokirchneriella subcapitata and Daphnia magna, the relative toxicity relationships were: lincomycin>flumequine>sulfamethoxazole for P. subcapitata and sulfamethoxazole>flumequine>lincomycin for D. magna. The preliminary environmental risk assessment was conducted following the European Medicines Agency Guideline. Predicted no effect concentrations (PNECs) were derived from the acute and chronic toxicity data obtained from P. subcapitata in this study and from the literatures. Risk quotient for lincomycin was 1.82 calculated by EC50 of P. subcapitata and 1.102 for sulfamethoxazole based on the NOEC of S. leopolensi. The observed results suggest that, for lincomycin and sulfamethoxazole, potential risks still exist to the aquatic environment. The toxicity of binary mixtures was based on the effects on P. subcapitata. Simple addition effect was observed with the combination of lincomycin and sulfamethoxazole. On the other hand, the mixture effects of three antibiotics tested in the present study at the maximal MEC levels displayed no adverse effect or inhibition to P. subcapitata, D. magna and C. carpio.