Distribution And Migration Of Rare Earth Elements In Groundwater Around Rare Earth Tailings Pond

In recent years,with the rapid development of science and technology,rare earth elements have been widely used in all walks of life.As groundwater is a potable water source,it is of great significance to understand the distribution of rare earth elements in groundwater for its ecological risk assessment.Therefore,this study takes the groundwater around the typical rare earth tailings reservoir area in China as the research object,combining on-site monitoring with indoor simulation,the method of combining study the environmental behavior of the rare earth elements change,determination of physical and chemical indicators in a typical well point of groundwater,the total amount of rare earth elements,microorganisms,etc.,using multivariate statistical analysis method of exogenous substances ammonium sulfate input on the physical and chemical properties of groundwater and its the influence of rare earth element distribution,to explore the biological and non-biological oxidation of the impact on the distribution of rare earth elements.In addition,the Visual Modflow software was used to predict the migration range of rare earth elements in different seasons in the research area after many years,so as to speculate the average annual migration speed of rare earth elements and make a supplement to the previous research which only predicted one season.The main results obtained are as follows:?1?The input of ammonium sulfate will affect the physical and chemical properties of groundwater,and thus affect the change of the total amount of rare earth elements in groundwater.SO₄^2-and Cl^-,TOC and?REE has very significant positive correlation,correlation coefficients were 0.998,0.990,0.997,and ammonia nitrogen,F^-,La significant positive correlation,the correlation coefficient of 0.975,0.968,0.962,respectively.Ammonia nitrogen and Mn,F^-,and La extremely significant positive correlation,correlation coefficients were 0.995,1.000,0.999,and the pH very significant negative correlation,the correlation coefficient was 0.993,and Cl^-,TOC,?REE was significantly related to the correlation coefficient was 0.986,0.980,0.989.Ammonium sulfate has a significant inhibitive effect on the dominant strains Acinetobacter and Legionella in groundwater.?2?By measuring the contents of Fe,Mn and Ce in the control group at GW3,the results of adding ascorbic acid and sodium azide were consistent,and non-biological oxidation played a major role.Actinobateria and Proteobacteria were the dominant flora in the groundwater surrounding the tailings pond,which may be due to the rich alkaline organic matter in the groundwater surrounding the tailings pond,meeting the growing environmental requirements.The column leaching experiment showed that the leakage of water in the reservoir changed the transformation of the microflora.Through the correlation analysis of environmental factors,the dominant microflora was not affected by the physicochemical properties and rare earth elements in groundwater,while Verrucomicrobia was inhibited by Mn and La.?3?The average annual velocity of simulated La element was 61.97 m/a,and the average annual velocity of simulated Ce element was 46.24 m/a.The average annual velocity of simulated rare earth amount is 56.07 m/a.Although the change law indicated that the concentration of rare earth elements decreases with the increase of distance,it also indicated that the rare earth elements will further migrate over time.