部分除草剂与重金属混合物对发光菌的毒性

以5种不同类型除草剂和4种重金属为混合物组分,探索混合物毒性变化规律.应用微板毒性分析方法,测定了百草敌、磺草灵、西草净、除草定、环嗪酮、CdCl2·2.5H2O、Ni(NO3)2·6H2O、CoSO4·7H2O和ZnSO4·7H2O对淡水发光菌—青海弧菌Q67(Vibrio qinghaiensis sp.—Q67)的发光抑制毒性.应用非线性最小二乘拟合技术模拟实验剂量-效应数据.结果表明,5种除草剂与4种重金属化合物的剂量-效应曲线(DRC)均可用Weibull函数有效表征.为了全面考察各种不同浓度组成的混合物对Q67的毒性,设计了9个组分同时存在的3个等效应浓度比(EECR)混合物和10个均匀设计浓度比(UDCR)混合物.同样应用微板毒性分析方法测定了各个混合物对Q67的抑制毒性,并应用非线性最小二乘拟合技术模拟了其剂量-效应曲线.通过剂量加和(DA)与独立作用(IA)模型综合分析了各个混合物对发光菌的毒性变化规律.结果表明,不同类型除草剂与多种重金属的各种浓度组合的混合物毒性均可用DA模型进行预测和评估.

Mixture Toxicity of Herbicides and Heavy Metal Compounds to Photobacteria (Vibrio qinghaiensis sp.-Q67)

Mixture toxicity of five kinds of herbicides with the different structural features and four heavy metal compounds was examined. The inhibiting toxicity of dicamba, asulam, simetryn, bromacil, velpar, CdCl2·2.5H2O, Ni(NO3)2·6H2O, CoSO4·7H2O and ZnSO4·7H2O on the luminescence of a freshwater photobacteria, Vibrio qinghaiensis sp.—Q67 was determined using the microplate toxicity analysis (MTA), respectively. Using the nonlinear least squares (NLS), the dose-response curve (DRC) models between the observed inhibition toxicity and the dose (concentration) of nine toxicants under study were developed. It was shown that the dose-response relationships of 5 herbicides and 4 heavy metal compounds were effectively described by the Weibull function. To systemically examine the mixtures with the diverse concentration compositions of nine toxicants, three equivalent-effect concentration ratio (EECR) and ten uniform design concentration ratio (UDCR) mixtures were designed. Using the same MTA as above, the toxicities of all EECR and UDCR mixtures were determined. The total-dose response curves of the mixtures were fitted using the NLS. The toxic interactions in the mixtures were examined and evaluated using the dose addition (DA) and independent action (IA) principles. The results showed that the mixture toxicities of five herbicides and four heavy metals could be predicted and evaluated by the DA model.