利用密閉式藻類毒性試驗評估鄰苯二甲酸酯類之毒性

Abstract

本研究結果發現14個鄰苯二甲酸酯類及4個對苯、2個間苯二甲酸酯類在BOD瓶藻類毒性試驗之下皆具有急毒性，毒性隨碳鍊增長而變強，且三個反應參數(△DO、Final yield及Growth rate)下是以△DO敏感度最高﹔與其他物種比較的部分，發現除了低分子之化合物敏感度較低之外，敏感度都比其他物種的高，若是與其他藻種比較，則敏感度上的表現是差不多的﹔替代物種部分，月芽藻與Fathead minnow 及Water flea迴歸結果R2在0.89〜0.93，因此對於此類化合物可以利用藻類來預估較高營養階層的魚類與水蚤類。QSAR的結果發現若去除接有較強的氫離子游離能力的4個胺基及硝基之化合物及另外兩個outliers點(Diphenyl Phthalate、Butyl (2-ethylhexyl) Phthalate)後，迴歸毒性與log P的結果得到不錯的R2值0.88〜0.92，若單純討論鄰苯二甲酸酯類會得到更高的R2值0.93〜0.95之間，進而使用log P*MW當作參數得到更高的R2值0.95〜0.96；最後利用基線毒性預測此類化合物，發現除了outliers之外，殘差值都界於±1個log單位間，因此判斷其餘化合物是屬於非極性麻醉毒性機制的。

This paper presents the toxicity data of benzenedicarboxylate(14 phthalate esters、4 terephthalate esters and 2 isophthalate esters) on Psudokirchneriella subcapitata (green algae) assessed by a new algal toxicity testing technique conducted under air-tight environment. Based no DO production, median effect concentration (EC50) varies from 0.037 mg/L (Dihexyl phthalate, DHP) to 344 mg/L(Bis(Methoxyethyl) phthalate, BMOEP). The endpoint of algal DO production reveals more sensitive that from final yield and growth rate. Compared to literature data, Psudokirchneriella subcapitata are apparently more sensitive to the other organisms such as Fathead minnow、Daphnia magan or T. pyroformis besides the low molecular phthalate(Dimethyl phthalate and Diethyl phthalate). Furthermore, good correlations between toxic effects observed from Psudokirchneriella subcapitata and other aquatic organisms were found. Hence, algal toxicity test can be considered as a surrogate test for estimating the toxicity of phthalate esters to Fathead minnow and Daphnia magna. Quantitative Structure-Activity relationship (QSAR) was established based on chemical hydrophobicity , 1-octanol/water partition coefficient (log P) with R2 equal to 0.88〜0.92. If the parameter of log P* Molecular weight is used, we can get a greater R2 0.95〜0.96. The purpose we used this parameters was not only to get a great R2, but to describe the physiological aspects relative to the mode of action of the chemicals assayed. Finally, we used the equation of baseline toxicity built by our laboratory, only six compounds had more than 1 residual. According to this result, we determined the mode of action of other 14 compounds were non-polar toxicity.