以密閉式藻類毒性試驗方法評估一級炔丙基醇類之毒性

Abstract

本篇研究係以月芽藻 (Pseudokirchneriella subcapitata)針對16種一級炔丙基醇類(包含Primary propargylic alcohols and Primary homopropargylic alcohols)進行48小時密閉式藻類毒性試驗。將實驗結果，利用△DO、Final yield及Growth rate做為反應後之觀測終點，採用Probit模式算出半致死濃度 (50% Effect concentration，EC50)，由實驗結果結果顯示，炔基接於2的位置毒性較炔基接在3的位置高，再將求得毒性試驗以log(1/EC50)與logKOW進行回歸分析，扣除掉機制較為特殊的2-propyn-1-ol後得到以Final yield為反應終點之最佳回歸方程式(R2= 0.9)。針對低影響濃度進行敏感性之比較，(△DO、Final yield及Growth rate)，為 NOEC 較 EC10能提供對水體生物更嚴謹的保護標準。而在本研究之三個反應終點當中對於一級炔丙基醇類類之敏感性最高者為細胞密度變化量，其次為溶氧產生量，而敏感性最差之反應終點為生長率。與其他水體物種進行敏感度比較可以發現以魚類敏感性最高、其次為月芽藻，敏感性最差者為纖毛蟲。

The objective of this study is to study the toxic effect of primary propargylic alcohols on Pseudokirchneriella subcapitata using a closed system test. The effects of primary propargylic acids were evaluated by three kinds of response endpoints, i.e., dissolved oxygen production, cell density and algal growth rate. Median effective concentratons (EC50s) were estimated using the Probit model with a test duration of 48hr. Primary propargylic alcohols with alkene on the second position exhibit higher toxicity than alkene on the third position. The quantitative structure-activity relationships (QSARs) were established based on the 1-octanol/water partition coefficient (logKow) and using log(1/EC50) , 2-propyn-1-ol was not included , revealed a good regression relationship (R2=0.9, based on final yield). The results also reveal that the value of the lower effect concentration of the primary propargylic alcohols (cell density, algal growth rate, and the dissolved oxygen production). This demonstrates that the NOEC value can offer a better standard for protecting our aquatic environment than the EC10 value . Hence, comparing with other aquatic organismsthe acute toxicity data , The order of the relative sensitivity is then obtained as follows : Fathead minnows> P. subcapitata > Tetrahymena pyriformis.