The Toxicities Of Six Types Of Heavy Metals And Their Mixtures To Luminescent Bacteria

With the mining,farm chemical fertilizer and pesticide application,as well as industrial and agricultural wastewater,sewage and unreasonable discharge of water and other reasons,the heavy metal content of water is increasing rapidly;heavy metal pollution incidents,such as child blood lead poisoning,cadmium poisoning Wait.Heavy metal pollution has become the focus of attention in recent years,Guangxi Hechi,Guangxi Hezhou,Shaanxi Fengxiang,Henan Jiyuan,Jiangsu Yancheng,Guangdong Jingyuan,Gansu Huixian,Zhejiang Taizhou and other places heavy metal pollution incidents.Guangxi is the focus of non-ferrous metal producing areas,known as "non-ferrous metal town" in the world.In the 1960 s,heavy metal pollution in Japan,especially Minamata disease(Hg pollution)and bone disease(Cd pollution),showed that heavy metals in aquatic environment could have serious effects on all living organisms.Therefore,it is necessary to study the pollution of heavy metals in water environment.In this paper,six kinds of heavy metals(Ni,Fe,Zn,Pb,Cd and Cr)were used as the target compounds,and the compounds were determined by time toxicity analysis.Time toxicity at different exposure time points for Q67 and VF.The binary mixtures and ternary mixtures were designed by inverse cross level ray method,direct homogeneous ray method and equivalent fixed concentration ratio method.The time toxicity of them was studied.Based on the concentration plus model and the independent action model,To investigate the toxic interactions of the mixtures at different times within different concentrations,to predict the combined toxicity of the chemical mixtures with interactions.The experimental results show that the CRC curves of the six compounds can be fitted with the least squares support vector machine,Logit or Weibull function at different time points,and the fitting effect is good.Some of the single heavy metal compounds have a weaker stimulating effect on Q67(Pb has a more pronounced hormesis phenomenon).And the mixture with the exposure time,the gradual emergence of hormesis phenomenon,the stimulating effect concentration range is gradually widened,stimulating effect increased,but its stimulating effect is still weak.In the high concentration area,with the prolongation of exposure time,its toxicity gradually increased.In the experiment,six kinds of heavy metal compounds had a significant effect on VF,but their binary and ternary mixtures had more obvious hormesis phenomenon on VF.The maximal amplitude was 8h,and the exposure time was 15 min,The concentration of toxic changes were not obvious,with the exposure time,the gradual emergence of hormesis phenomenon,the effect of stimulating concentration range is gradually widened,stimulating effect increased.The traditional CA and IA models are not applicable for accurate prediction and evaluation of the toxicity of mixtures that interact with each other.CA and IA models can not predict the interaction of low concentration regions,and they show obvious synergistic effect in the high concentration region.The reason for this phenomenon may be that the low concentration of the compound is the main line,and the low concentration of the compound The correlation of data with monotone function is not high,which affects the prediction of CA and IA models.