以密閉式藻類毒性試驗評估工業常用非極性麻醉有機物之混合毒性

Abstract

本研究利用BOD瓶進行密閉式藻類（Raphidocelis subcapitata）毒性試驗，評估非極性麻醉有機物之毒性。 實驗中選定DO觀測終點所求得的毒性數據與其他物種進行迴歸分析， 迴歸結果則皆呈現高度相關（R2值≧0.84），這可推論出藻類與其他物種的分析方法（不含Nitrosomonas）的致毒機制有很高的相關性，且可知本試驗方法不僅敏感性高且與其他的物種且有良好的相關性可做為替代性試驗。 在log Kow迴歸結果的部分，試驗中有機物不管以DO、final yield與growth rate迴歸皆有很高的相關性，如此顯示Narcosis I的毒性會隨著log Kow愈大時而有增加的趨勢，其毒性的產生與溶解在水相與薄膜的滲透性有直接的關係，在此可由迴歸結果去預測其它工業常用的非極性麻醉型有機物的毒性。 由混合毒性結果可得知藻類對於非極性麻醉型有機物混合毒性大多以濃度相加呈現，此結果與文獻回顧記載的其它物種試驗的結論相同，實驗中發現ρ值皆為1，這顯示非極性麻醉毒性物質容忍度分布為正相關，另外也發現λ值也近似於1，這樣的結果代表兩有機物作用在生物受體位置相當接近。

In this study, we use BOD bottles to perform a close-system algal(Raphidocelis subcapitata) test to assess the toxicity of two kinds of non-polar narcotic chemicals. The comparison between the obtained EC50 values and toxicity data from the literature points out the good agreement between the BOD bottle test (Raphidocelis su.) and those of nine widely used test methods, i.e., Fathead minnow, Vibrio fi., Microtox, Polytox, Spriotox, Shk1, Activated sludge, Daphina ma. and Tetrahymena. In this study, log Kow values of narcosis Ι compounds (using the BOD bottle test and nine bioassays) were reported. The toxicity data in our study and other bioassay have good correlation with log Kow value and also prove that there is well relationship between three endpoints. We developed a QSARs model to describe and predict the toxicity of industrial organic chemicals. This assay is not only applicable for toxicity testing of single compounds. It can be also used for toxicity assessment of volatile fractions of environmental samples. Our study shows that the additivity effects is the same as the literature for industrial chemical mixtures during the acute tests. A series of isobolograms were generated from this study. These diagrams were analyzed, through Multox model.fitting, to determine ρ and λ. For a single-species culture of organisms, ρ was found to be always 1, despite the type of chemicals involved. For two narcosisΙ toxicants, λ was approximately equal to 1, indicating similar mechanisms of toxicity. The statistical analysis has provided a meaningful biological interpretation to the above model parameters.