以光合作用為反應參數之藻類毒性實驗設計

Abstract

近年來，危害性物質不斷地製造與釋放而促使環境急速惡化，為瞭解自然水體遭受衝擊的程度，吾人必須建立一套生物試驗的方法加以量測，而其中以藻類生物試驗最為廣泛使用。現行各藻類標準試驗方法皆屬於批次式，主因為其簡單、便宜且處理量大，但由於試驗時間長達三至四天，故在實際應用上並不適合當作一項快速的檢測方法。 本研究主要是利用藻類 (Selenastrum capricornutum) 行光合作用產氧量的變化來設計一個短期 (<24-hr) 藻類試驗，且因此為密閉式系統，除可進行傳統重金屬毒性評估，亦可加以評估揮發性有機毒物。依據試驗結果，在以連續式培養藻類當作來源、初始植種細胞密度為1.0*E+5、試驗時間為12小時、營養基質強度維持與 U.S. EPA 相同及不添加任何螯合劑條件下，這些參數為最適宜值。以其不錯的試驗敏感度和再現性，對於六種重金屬的效能評估，效力在批次式與連續式藻類試驗之間，如與其他生物試驗方法相較，亦擁有良好的相關度，表示此研究是一套可以信賴的生物試驗方法。

The transport and capacity of potentially hazardous chemicals in the natural environment have received increased attention in recent years, necessitating the development of bioassay systems. Toxicity testing with microalgae has been used extensively for assaying the impact on water quality. Now the general test is belong to Batch Test that consists in simpler and cheaper. But it requires 3 or 4 days to complete; therefore, it’s not suitable as a rapid screening method for measuring the toxicity of test materials. The primary objective of our research is to design a short-term (<24-hr) algal assay which measured oxygen evolution. The new assay is feasible to evaluate metal and organic toxicity because it is a close system. Based on the test results, these parameters at initial cell density = 1.0*E+5, test time = 12hr, 100% medium strength and no chelator-EDTA are optimum. The performance (sensitivies) of the oxygen evolution test is between Batch and Continuous Test, employing six different metal toxicants. And our research is a trusting method from good correlation with other bioassay system.