Study On Pollution Characteristics Of As,Cd,Cr,Ni And Pb In Wet Deposition Of Jinan And Its Biological Toxicity To Zebrafish

With the rapid development of China's industrial and agricultural production and the increase in urban population and motor vehicles,the emissions of heavy metal to the environment continue to increase,resulting in atmospheric heavy metal pollution has become an environmental problem cannot be ignored.Heavy metals in the atmospheric environment can be transported into the surface water and soil by atmospheric sedimentation,resulting in secondary pollution of soil and water bodies and transferring heavy metals to animals and plants through certain biochemical effects.Therefore,this paper analyzes and evaluates the pollution of heavy metals As,Cd,Cr,Ni and Pb in the wet deposition of Jinan City.On this basis,the zebrafish was selected as the tested organism to study the combined biotoxicity of five heavy metals in the wet deposition of Jinan.In this study,the self-developed wet deposition automatic acquisition device was used to collect the samples.The results of heavy metals such as As,Cr,Cd,Ni and Pb in the wet deposition of Jinan show that the change trend of the five heavy metals'average concentration in wet deposition is higher in winter and spring than in summer and autumn,with the highest concentration in winter.The fluxes of wet deposition in summer is significantly higher than that in other seasons,and Pb in five heavy metals were the highest,followed by Ni,Cr,As and Cd.Through the principal component analysis and cluster analysis,five kinds of heavy metals of Jinan wet deposition can be divided into three groups:Pb and Cd,Cr and Ni,As.Cd and Pb may have a large correlation,probably mainly from urban traffic;Cr and Ni may mainly come from industrial activities;As mainly from coal combustion.The concentration of heavy metals in wet settlement is lower than that of surface water class ?,except that the lead is slightly higher than the drinking water health standard,the rest are lower than the standard.The potential ecological hazard index of As,Cd,Cr and Pb in wet deposition of Jinan was analyzed by the potential ecological hazard index method.The potential ecological risk index of four seasons was winter>epring>autumn>summer,the potential ecological risk level reached "slight" hazard level.The results show that the total potential ecological risk of arsenic,cadmium,chromium and lead in the wet deposition of Jinan is at a slight risk.The results showed that compound exposure significantly enhanced the toxic effects of heavy metals on zebrafish,in which cadmium played a major role in the behavioral toxicity induced by compound exposure.And heavy metal has obvious time-effect and concentration-effect relationship on zebrafish toxicity.When a single exposure,heavy metal As and Cr had a low lethality of zebrafish,and there was no significant difference in swimming rate between experimental group and control group;Cd,Ni and Pb significantly increased the death rate of zebrafish at high concentrations and showed a significant inhibitory effect on swimming speed.When the concentration of compound concentration is 6 times of the environmental concentration,the toxicity of the larvae is significantly increased;10 times of the environmental concentration is significantly inhibited the movement speed of larvae;The larvae in the two highest concentrations were all dead.It can be seen that there is no significant biotoxicity by single exposure and compound exposure in the environmental concentration,but significantly reduced the swimming speed of larvae when the exposure concentration was increased to 6 times of environmental concentration.