The Tolerance And Phytoremediation Potential Of Three Kinds Of Aquatic Plants On The Lead Tailing Leaching Liquid

This paper chooses three kind of aquatic plants?Pontederia cordata,Alisma orientale and Eichhornia crassipes?as experimental materials to analyze the interrelationship between the aquatic plants and Pb tailing leaching liquid.Through measuring several indexes of these three plants,such as biomass,the contents of heavy metals and migration rate of each part,chlorophyll,conductivity,free proline,glutathione,ascorbic acid,this paper will research the growth index of aquatic plants under the pressure of different concentration of Pb tailing leaching liquid.It provides theoretical basis and technical support for the water body remediation of the polluted Pb tailings leaching liquid.The main results of this study are as follows:?1?By researching the effects of Pb towards the seedling growth and the metal ions accumulation of the Pontederia cordata,Alisma orientale and Eichhornia crassipes seedling.Based on the analysis of the height,root length and dry weight of the plants underground and aboveground,we can find that the underground dry weight is significantly heavier than the part of aboveground.It indicates that Pontederia cordata has strong tolerance to PBL.Under the process of 100%PbL,the above-ground part of the Pontederia cordata and Eichhornia crassipes have more contents of Pb,their content are 5.84 and 5.3 times bigger compared with the control part,Pontederia cordata have the most contents of Pb among the underground part of plants,its Pb content of underground part is up to 371.67?g/g.The operation coefficient of Pontederia cordata is greater than 1,and operation coefficients of Alisma orientale and Eichhornia crassipes are less than 1.results show that these three plants could be used for the phytoremediation of Pb tailing leaching fluid and its contaminated environ ment,and the Pontederia cordata is the best one.?2?The results show that under the stress of PbL,the Chl.a,Chl.b and Cxc of Pontederia cordata,Alisma orientale and Eichhornia crassipes decrease obviously.The electrical conductivity of Pontederia cordata,Alisma orientale and the underground part of Eichhornia crassipes decreases gradually.MDA content of the underground part of Alisma orientale increases significantly,and the MDA content of the other two species increases slightly.The activity of POD,SOD and GSH in the three species of the aboveground part of aquatic plants were induced by PBL.Above-ground part and underground part of Alisma orientale 's SOD activity is higher than the other two.The Underground part of the Pontederia cordata's POD activity is higher than that of the others.The Underground part of the Eichhornia crassipes's GSH activity is higher than than the others.The activity of Pro in Pontederia cordata and Alisma orientale increase slowly,and the activity of Pro in Eichhornia crassipes's aboveground part decline after rising.The activity of Pro in the underground part of the three plants firstly increased and then decreased.The results show that different plants have different responses to PbL stress,and the antioxidant system plays a very important role in the resistance of the three aquatic plants under the PbL stress.?3?Through hydroponic method,this paper researches the effects of Pontederia cordata,Alisma orientale and Eichhornia crassipes to the water polluted by Pb.The result shows that the Pb content in 100%Pontederia cordata,Alisma orientale and Eichhornia crassipesare is lower than the Pb content in tailing leach ate.The chemical oxygen demand in solution for Alisma orientale cultivation is higher than Pontederia cordata and Eichhornia crassipes.The electrical conductivity of Eichhornia crassipes cultivation is higher than Pontederia cordata and Alisma orientale.The conductivity increases significantly with the concentration of PbL increasing.In the 100%PbL water,Eichhornia crassipes's EC respectively is Alisma orientale's and Eichhornia crassipes's 3.97 times and 5.8 times.The pH data of Pontederia cordata cultivation is higher than Eichhornia crassipes and Alisma orientale.The manganese removal capacity of the solution for Pontederia cordata cultivation is the strongest.The P removal capacity of the solution for Alisma orientale cultivation is the strongest.The NH₃-N removal capacity of the solution for Eichhornia crassipes cultivation is the strongest.The research results show that Pontederia cordata,Alisma orientale and Eichhornia crassipes have very good Pb removal ability to water.