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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(EquRay)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16 h)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,没有协同或拮抗作用.
The concentration plus (CA) model is one of the most commonly used models for assessing and predicting the toxic effects of chemical mixtures and has been widely used in multiple mixture systems, such as drug combination and pesticide mixing. However, CA can not be used to contain different effect groups The mixture system of three components, namely MET, SIM and HEX, with different time-dependent toxicity characteristics, Direct binary method (EquRay) was used to construct binary mixtures of them. Using Q67 strain of Qhaihai as the tested organism, the mixture groups were determined at 6 different times (ie 0.25, 2, 4, 8, 12 and 16 h) The results showed that the three kinds of herbicides had different luminescence inhibitory toxicity to Q67 at different times: MET Toxicity increased obviously with time. The toxicity of SIM did not change significantly at different time, but the toxicity of HEX began to increase with the increase of time, and then changed little. The time variation of the toxicity of binary mixture with the mixture Component The toxicity of binary mixture system of MET and HEX gradually increased with the exposure time, the MET-SIM system began to decline and then slowly increased, while the toxicity of SIM-HEX system was not obvious at different time; The CA model analyzes the toxicity changes of all binary mixtures at different time points indicating that they are additive and have no synergistic or antagonistic effect.