Study On Plant Remediation Of Heavy Metal Contaminated Soil With Activator

With the continuous development of industry and mining industry,soil heavy metal pollution is becoming more and more serious,and the environmental problems and agricultural product safety problems caused by heavy metal pollution are increasingly prominent,posing a serious threat to human health,so it is urgent to solve the problem of soil heavy metal pollution.In recent years,phytoremediation has gradually become the preferred way of soil in-situ remediation because of its environmental friendly and resource recovery characteristics.In this paper,the polluted soil of Tongling and Ma'anshan in Anhui Province was selected as the research object.The super enrichment plants of heavy metals,such as Sedum plumbizincicola,Pteris vittata,Tagetes erecta,Tagetes patula and Mirabilis jalapa,were selected to repair the polluted soil by the way of plant mixed cropping and activator strengthening.The absorption,accumulation and transfer ability of heavy metals by each plant were analyzed,and the combination of activator and plant was evaluated.The practical significance and environmental beautification value of these methods for remediation of polluted soil can provide data support for remediation of polluted soil in Tongling and Ma'anshan.The main research results are as follows:(1)The content of Cd in the aboveground part can reach 239.87mg/kg?379.94 mg/kg,especially when 3mmol/L EDTA and 10mmol/L citric acid are added,the concentration of Cd in Sedum plumbizincicola increased 139.46%,126.53% and the soil purification rate reached 60.02% and 56.78% respectively.No matter in single cropping or mixed cropping mode,adding 3mmol/L EDTA increased the content of heavy metals in the aboveground and underground parts of Pteris vittata and three kinds of flowers,especially the accumulation of heavy metals in Tagetes patula increased by 9.38%?131.82% compared with that in the absence of activator.(2)The content of Cd and Cu in the aboveground part and root system of Pteris vittata and three kinds of flowers is mainly in the mode of mixed cropping greater than that of single cropping,but the effect of as absorption and accumulation of Tagetes erecta,Tagetes patula and Mirabilis jalapa is in the mode of single cropping greater than that of mixed cropping,while the absorption and accumulation of as by Pteris vittata is on the contrary,which is much stronger than that of the three kinds of flowers.In a word,Pteris vittata and Tagetes patula have the best absorption and accumulation effect on heavy metals as Cd and Cu,and can achieve the goal of environmental beautification and soil restoration.(3)When EDTA,citric acid and tea saponin were added,the p H value of soil solution decreased.When the concentration of the three activators was 1,5,3 mmol/L,the most significant reduction was observed.In the experiment of centipede grass mixed with flowers,except TP and TP-PV treatment,the p H of each treatment decreased with the addition of activator after 3mmol/L.The results showed that the p H value of soil could be reduced by adding activator,and the p H value of soil could be reduced by mixed cropping compared with monoculture.