中文摘要：

以斜生栅藻（Scenedesmus obliquus）为受试生物，采用藻类急性毒标准方法研究十六烷基三甲基溴化铵（CTAB）、十二烷基苯磺酸钠（LAs）和辛基苯基聚氧乙烯醚（TX-100）3种较常用的表面活性剂对藻类的生态毒性。通过斜生栅藻的密度及过氧化物酶活性的测定对其作用机制进行探讨。结果表明，在EC50附近，表面活性剂浓度越大其毒性越强，不同离子型表面活性剂对斜生栅藻毒性从大到小为阳离子（CTAB）、阴离子（LAS）、非离子（TX-100）。表面活性剂毒性作用机制主要是被吸附在藻细胞的磷脂双分子膜结构表面，从而引起膜结构的破坏和功能的丧失，进而导致细胞死亡。

英文摘要：

In this paper the standard method of algal acute toxicity determination was used to investigate the acute eeotoxicity of some commonly used surfactants, i.e. cetyl trimethyl ammonium bromide （CTAB）, linear alkylbenzenesulfonate（LAS） and ethyl polyoxyethylene octylphenol（TX- 100） to Scenedesmus obliquus. The mechanism and impact of the three compounds on biomass and peroxidase activity of Scenedesmus obliquus were discussed. The biomass evaluation re-suits show that in the vicinity of EC50, greater surfactant concentration exhibited stronger toxicity to algae. The order of toxicity significance of different surfactants on Scenedesmus obliquus was as follows： cationic surfactants（CTAB） 〉 anionic surfactants（.＇LAS） 〉 non-ionic surfactants（TX- 100）. Compared with other types of surfactants, positively charged surfactant is easier to be adsorbed on the negatively charged membranes of Scenedesmus oblique and destroy the membrane further; it is probably the main reason for the cationic surfactants to possess stronger effect in inhibiting the algal activity. The mechanism of surfactants toxicity involves adsorption into the phospholipid bilayer of algal cells, leading to the destruction of membrane structure and loss of function, and then to the death of cells. The results of peroxi-dase activity evaluation show that the greater surfactant concentration is, the lower its peroxidizing enzyme activity is. When the density of surfactant is low, it may induce the elevated activity of protecting enzyme and peroxydizing enzyme to eliminate ultra oxygen free radicals which resulting from the surfactant-causing injury in cells, and further maintain the normal physiological function of cells. However, when the surfactant concentration is high, the concentration of ultra oxygen free radical would surpass the capability of self-clearance, causing injury or even death of cells. The influence of CTAB to the peroxidizing enzyme activity was greater, where the enzyme activity in 72 hour was lower than 48