多组分苯胺类混合物对发光菌的抑制毒性

以淡水发光菌——青海弧菌(Q67)为指示生物,96微孔板为实验反应载体,微板光度计为发光强度测试设备,测定了苯胺、邻甲基苯胺、对甲基苯胺、邻硝基苯胺、对硝基苯胺及其混合物对发光菌的发光抑制毒性,应用非线性最小二乘拟合技术与剂量加和(DA)及独立作用(IA)原理研究了混合物的毒性规律.1)分别测定每种化合物的剂量-效应数据并进行非线性拟合.结果表明,5种苯胺类化合物的剂量-效应曲线(DRC)均可用Logit与Weibull函数有效表征,从这些模型估算的半数效应浓度负对数值(-logEC50)分别为2.11、2.35、2.49、3.60和3.88(EC50单位:mol·L-1),可知其对发光菌的毒性大小顺序为:苯胺<邻甲基苯胺<对甲基苯胺<邻硝基苯胺<对硝基苯胺.2)根据组分EC50、EC10和EC1设计3个等效应浓度比混合物进行混合物毒性实验,并对混合物剂量-效应数据进行非线性拟合得到混合物DRC.结果表明,混合物DRC可用Box-Cox-Logit与Box-Cox-Weibull函数有效表征.3)根据单一化合物DRC模型,分别应用剂量加和(DA)与独立作用(IA)模型对混合物DRC进行预测.结果表明,无论考察混合浓度比例还是效应水平,剂量加和模型都能准确预测苯胺类混合物的毒性,而独立作用模型倾向于高估混合物毒性.

Inhibition Toxicity of Mixtures of Substituted Anilines to Photobacteria

Using freshwater photobacteria-Vibrio-qinghaiensis as indicator organism,96-well microplate as experimental reaction carrier, microplate luminometer as testing equipment to determine luminous intensity of photobacteria, the photobacterium luminescence inhibition toxicities of aniline(A1),2-methylaniline(A2),4-methylaniline(A3),2-nitroaniline(A4),4-nitroaniline(A5),and their mixtures were determined. The joint toxicity varieties of various mixtures to photobacteria were examined by a nonlinear least-squares fitting technique combined with the dose addition(DA)and independent action(IA)principles. Firstly, an optimal microplate toxicity experiment was designed by 12 different test concentrations in 3 replicates for each of poisons and 12 water untreated controls in 1 plate and every plate in 3 replicates at least. Then, the experimental dose-response data were fitted using various nonlinear functions and the results showed that the dose-response curve(DRC)for each of five individual compounds was effectively characterized by Logit or Weibull function. The-logEC50 values of five substituted anilines(from A1 to A5)computed by the fitted DRC models were 2.11, 2.35, 2.49, 3.60, and 3.88, respectively(unit of concentration: mol·L-1),which revealed that the toxic order was aniline(A1)<2-methylaniline(A2)<4-methylaniline(A3)<2-nitroaniline(A4)<4-nitroaniline(A5). Thirdly, the toxicities of the fixed concentration ratio mixtures designed based on 3 equivalent-effect concentrations such as EC50, EC10, and EC1 were determined in the same method as the individual toxicant and results showed that the DRCs of the mixtures were expressed as a Box-Cox-Logit or Box-Cox-Weibull function. Finally, the response curves of the mixtures were compared with the predictive response curves derived from the DA and IA models respectively and the results implied that there are no significant difference between the experimental response curve and predictive one by DA model. However, IA model tended to overestimate the mixture toxicities.