以密閉式藻類毒性試驗評估非極性麻醉有機物之毒性

Abstract

本研究利用BOD瓶進行密閉式藻類（Raphidocelis subcapitata）毒性試驗，評估三類非極性麻醉有機物之毒性，包括氯苯、含氯乙烷及含氯甲苯類毒物。 在試驗終了時，量測溶氧變化量（Based On DO）及生物質量（Based On Biomass）兩種試驗終點，生物質量即是計算試驗終了時之藻類細胞密度，接著以Probit model分析兩試驗終點的EC50值。除了1,1,2,2,-四氯乙烷和六氯乙烷外，以溶氧為試驗終點時皆得到較敏感之EC50值。在QSAR方面，兩種試驗終點之R2分別為0.8868（Based On DO）與0.861（Based On Biomass），顯示毒物毒性與logP有良好之相關性。而物種間之毒性數據的比較，亦呈現良好之相關性（介於0.7到0.9之間）。因此，利用BOD瓶之藻類毒性試驗可得到敏感性、再現性及可靠性佳之毒性數據。而且此試驗方法簡單、方便又經濟，並且適用於揮發性有機物質。 此外，本研究以平均中斷值（cut-off value）作為選擇NOEC或EC10的客觀參考點，結果顯示NOEC比EC10提供生物更嚴謹的保護標準。而在模式最佳化方面，以weibul模式為最佳。

In this study, we use BOD bottles to perform a close-system algal(Raphidocelis subcapitata) test to assess the toxicity of three kinds of non-polar narcotic chemicals including chlorobenzene, chloroethane and chlorotoluene. The toxic test was ended based on DO and Biomass Methods. The Biomass Method was calculated the cell density difference between the start and the final points, and also use the Probit model to estimate and analyze the values of EC50. We found the EC50 values based on DO are more sensitive except 1,1,2,2,-tetrachloroethane and hexachloroethane. As for the QSAR, the R2 values of two endpoints are 0.8868 ( based on DO ) and 0.861 ( based on Biomass ) respective. It represented that the toxic values has good correlation coefficient with logP values. As for the correlation between different species, we also found good correlation coefficient and R2 values are between 0.7 and 0.9. Therefore, we can get toxic values with well sensitivity, reproducibility and confidence by using BOD bottle test. Besides, this method was very easy, convenient and economic to analyze high vaporizing organic matters. In addition, a cut-off value approach is proposed to determine whether NOEC or EC10 should be chosen for estimating low toxic effects. The results indicate that NOEC offers better protection to test organisms than EC10. As for the goodness of models, Weibul is the best fit model.