以密閉式藻類毒性試驗評估丙烯腈及其衍生物之個別毒性及與醛類之混合毒性效應

Abstract

本研究以藻類(Pseudokirchneriella subcapitata)利用BOD瓶進行密閉式藻類毒性試驗，使用溶氧變化、藻類生物質量以及生長率作為實驗終點，評估丙烯腈及其衍生物之毒性，同時將其與甲醛、戊二醛及三烴基苯甲醛等全類進行混合毒性試驗研究。 於單一試驗結果顯示，2-Chloroacrylonitrile最具毒性，Methacrylonitrile則毒性最低。取代基較雜的丙烯腈衍生物(3-Methoxyacrylonitrile、3-Ethoxyacrylonitrile、3-Dimethylaminoacrylonitrile)，其EC50值會有較大的變動，而在低濃度的部分，NOEC較EC10更可提供完善的保護。 在混合毒性的部分，小斜率與小斜率相混合時，皆以協同效應為主，若斜率變大，則效應則以加成或拮抗為主。在非交互作用模式預測方面，協同效應之實際觀察值皆比模式預測值更為強烈，經過HPLC分析，並未明顯觀察到兩種化合物間交互作用的變化。 而在Isobologram分析中，協同組(Glutaraldehyde+Methacrylonitrile)無論在何種混合比例下，皆呈現協同之現象，而在拮抗組中(3-Hydroxybenzaldehyde+2-Chloroacrylonitrile)，以溶氧變化作為實驗終點時，在不同混合比例下會發現加成的效應，而在生物質量及生長率方面則發現有Complex joint action的現象。

The purpose of the present study is to evaluate the toxicity of acrylonitrile and its derivatives, and their combined effects with aldehydes, using a closed-system algal toxicity test technique.

Among all the acrylonitrile derivatives, 2-chloroacrylonitrile was found to be the most toxic compounds, while methacrylonitrile was the least toxic one. For the low-toxic-effect concentrations, NOEC values were generally lower than the EC10 values and, therefore, were considered as being able to provide better protection to the aquatic environment than the EC10 values.

For the combined-effect studies, synergistic effects were consistently observed when both toxicants depict flat dose-response curves. Though the observed synergistic effects were stronger than that predicted by the non-interactive multiple toxicity model, the applied model did provide satisfactory predictions for the joint action modes for binary mixtures of toxicants. On the other hand, less-than-additive effects were observed for two toxicants associated with steep dose-response curves.