中文摘要：

摘要浓度加和（CA）模型是评估与预测化学混合物毒性效应的常用模型之一，已广泛应用于药物组合与农药混配等多个混合物体系．然而，CA不能用于包含不同时间具有不同效应组分的混合物体系，需要拓展．以具有不同时间依赖毒性特征的三种三嗪类除草剂即嗪草酮（MET）、西草净（SIM）和环嗪酮（HEX）为混合物组分，以直接均分射线法（ZquRay）构建它们的二元混合物，以青海弧菌Q67为受试生物，在6个不同时间（即0．25，2，4，8，12和16h）下测定各混合物组分及其二元混合物暴露于Q67时的发光抑制毒性，分析与归纳抑制毒性随时间的变化规律．结果表明，三种除草剂对发光菌Q67的发光抑制毒性具有不同的时间变化规律：MET的毒性随时间延长有明显增大的趋势，SIM的毒性在不同时间没有显著性变化，而HEX随着时间的延长毒性开始有所增加，而后变化很小；二元混合物毒性的时间变化规律与混合物组分有关，MET与HEX的二元混合物体系的毒性随暴露时间的延长而逐步增加，MET—SIM体系开始有所下降而后缓慢增加，而SIM—HEX体系的毒性在不同时间差异不明显；应用拓展后的CA模型分析所有二元混合物在不同时间点的毒性变化．表明都是加和的．没有协同或桔杭作用．

英文摘要：

The concentration addition （CA） model is a common model for the evaluation and prediction of mixture toxicity and has been widely used in many mixture systems such as drug combination and pesticide mixtures. However, it is neces- sary to extend the CA so that it is applicable in the mixture systems including components with different effects in different times. In this paper, three triazine herbicides, metribuzin （MET）, simetryn （SIM） and hexazinone （HEX）, which have differ- ent characteristics of the time-dependent toxicity, were selected as mixture components and their binary mixtures were de- signed by using the direct equipartition ray design （EquRay）. Taking V. qinghaiensis sp.-Q67 as test organism and 96-well microplate as exposure experiment carrier, the luminescence inhibition toxicities of three triazine herbicides and their binary mixtures were determined at six different time points （0.25, 2, 4, 8, 12 and 16 h）, The fluctuation tendency of the lumines- cence inhibition toxicity varying with time was analyzed. The results show that the inhibition toxicities of three triazine her- bicides to V. qinghaiensis sp.-Q67 have different characteristics of the time-dependent toxicity, i.e., the toxicity of MET ap- parently increases over time, while that of SIM is basically a constant in the range of testing time, but that of HEX first in- creases with time at the beginning stage and then is basically unchanged. Also, the toxicities of the binary mixtures consisting of three herbicides depend on not only the composition of the mixtures but also the concentration ratio of various compo- nents. The toxicity of binary mixture consisting of MET and HEX gradually increases over time, and that of binary MET-SIM mixture at first decreases and then slowly increases, while the toxicity change is not significant in the SIM-HEX mixture system. Moreover, all the toxicities of binary mixtures can be effectively predicted by the CA model which had been extended by regarding the concentration of no-effe