季铵盐阳离子表面活性剂对普通小球藻和斜生栅藻的急性毒性

Acute Toxicity of Quaternary Ammonium Cationic Surfactants to Chlorella vulgaris and Scenedesmus obliquus

以普通小球藻（Chlorella vulgaris）和斜生栅藻（Scenedesmus obliquus）为受试生物,采用批量培养方法研究了13种季铵盐阳离子表面活性剂（QACS,烷基链长度CL=8~18）对两种淡水藻的急性毒性。结果表明,13种QACS对普通小球藻和斜生栅藻的96h-EC50分别在0.108~9.472mg·L-1和0.085~12.188mg·L-1之间;且随着烷基链长度CL的增加,取代基相同的QACS对两种淡水藻的急性毒性逐渐增大。抛物线模型较线性方程能更好地拟合QACS的急性毒性参数lg（1/EC50）与辛醇/水分配系数lgKow以及与烷基链长度CL之间的关系,且对普通小球藻和斜生栅藻的拟合趋势相同,可为预测类似化合物对淡水藻的急性毒性提供参考。

Chlorella vulgaris and Scenedesmus obliquus, two green freshwater alga in environment, have been widely used to evaluate the im- pacts of xenobiotics duo to their sensitivity to contaminants. In this study, we investigated the acute toxicity of quaternary ammonium cationic surfactants（QACS）with different length of alkyl chain（CL=8~18）to C. vulgaris and S. obliquus. The results indicated that the 96 h-EC50 value of thirteen kinds of QACS on C. vulgaris and S. obliquus were 0.108~9.472 mg·L-1 and 0.085~12.188 mg·L-1, respectively. Further- more, the acute toxicity of QACS with the same substituent group on the two species of algae gradually increased with the increasing of CL. However, the different substituent groups had little effect on the acute toxicity of QACS with the same CL to the two green algae. The relation- ship between acute toxicity[lg（1/EC50）] and octanol-water partition coefficients（lgKow）, CL could be better fitted by parabola model than linear equation, and the fitting trends were same for the two green algae. The parabola equations for C. vulgaris and S. obliquus were lg（1/EC50）=-0.106 lgKo 2w ＋0.746 lgKow-0.830（R2=0.944）, lg（1/EC50）=-0.034 CL2＋1.051 CL-7.725（R2=0.945）and lg（1/EC50）=-0.119 lgK o2w ＋0.830 lgKow-0.812（R2=0.941）, lg（1/EC50）=-0.039 CL2＋1.218 CL-8.772（R2=0.945）, respectively, which could provide references for the prediction of acute toxicity for similar compounds to freshwater algae.