毒性化學物質對於月芽藻低影響抑制濃度NOEC、LOEC、EC10及NEC之研究

Abstract

本研究主要是針對本實驗室過去所做的108種毒性化學物質所做的密閉式藻類毒性試驗數據，其中包括了苯類、烷類、酚類、腈類、醛類、苯胺類、醇類、烯類、酮類、PAHs以及農藥，求得其EC10、NEC、 NOEC以及LOEC。在比較此四項觀測終點參數後，其敏感度的關係為NOEC≧EC10＞LOEC≒NEC。在ACR的部份則發現月芽藻急慢毒性間，在三大作用機制下：非急性麻醉性、急性麻醉性以及反應性，皆有良好的線性關係。 QSARs的關係中，對於基線毒性（Baseline toxicity）在EC10、NEC、 NOEC以及LOEC中，回歸方程式的R2以及Q2皆大於0.85以上，表示本研究對於非急性麻醉性毒性化學物質的低影響抑制濃度，具有良好的預測性。至於急性麻醉性化學物質，是以Log P以及ELUMO兩項參數進行回歸，亦有良好的結果。除此之外，本研究亦對於其文獻中的月芽藻(Pseudokirchneriella subcapitata)的結果以及其他物種水蚤（Daphnia magna）以及鰷魚（Pimephales promelas）進行敏感度的比較，結果發現以密閉式藻類毒性試驗的藻類毒性和鰷魚有良好關係性。

This research is aimed to estimate the low effect concentrations of 108 chemicals on Pseudokirchneriella subcapitata (green algae) assessed by a closed system BOD bottle test. Toxicants including benzenes, alkanes, phenols, anilines, aldehydes, nitrile, alcohols, ketones, pesticides, and PAHs were obtained NOEC, LOEC, EC10 and NEC. Among these parameters, NOEC was found to be generally smaller than EC10 and were apparently lower than LOEC and NEC. For non-polar narcotics , polar narcotics and reactive toxicants, distinct linear relationship were identified between EC50 and low effect concentration. For non-polar narcotic chemicals, the Quantitative structure-activity relationships (QSAR) of four parameters were based on the octanol-water partition coefficient (Log P) was established with R2 and Q2 above 0.85. Further, for polar narcotic chemicals, the discriminating parameters including log P, ELUMO (Energy of the lowest unoccupied molecular orbital)were chosen to predict the toxicity effectively. These equations also show a good prediction. Finally, compared to literature data, results from this study show that the closed system BOD bottle test is greater sensitivity than conventional batch test and a good correlation was found in comparison with the fish (Fathead minnow). Hence, algal toxicity test can be considered as a surrogate test for estimating the toxicity of chemicals to Fathead minnow.