Enhancement Effects Of The Coupling Between AC Electric Field And Fusarium Sp.A-2 On The Remediation Of Uranium Contaminated Soil By Macleaya Cordata

A large amount of uranium tailings,uranium waste rock and uranium waste residue will be produced in the process of uranium mining and smelting.Under the action of rainwater scouring and infiltration,the uranium in them will migrate to the soil,leading to uranium pollution in the soil.Uranium is a kind of heavy metal with high radiotoxicity and chemical toxicity,and has strong migration.It can accumulate in organisms through the food chain and other ways,posing potential risks to the ecological environment and human health.Therefore,the treatment of uranium contaminated soil is an urgent task in the field of environment.Electric field coupled microbial enhanced phytoremediation technology not only has the advantages of green environmental protection,small disturbance to the environment,lasting effect of remediation,but also can maintain electric field to improve the efficiency of plant remediation.Therefore,the addition of AC electric field and uranium-tolerant microorganisms to the phytoremediation of uranium-contaminated soil can effectively improve the phytoremediation efficiency of uranium-contaminated soil.In this paper,pot experiments were conducted to study the effects of the coupling between AC electric field(AC)and Fusarium sp.A-2(A-2)fungi on the biomass,uranium(U)enrichment and enzyme activity of Macleaya cordata(P),as well as the organic acid content,bioavailable uranium and microbial community structure in the rhizosphere soil.The results showed that compared with AC+P+U,A-2+P+U,and P+U groups,the fresh weight,plant height and total dry weight of Macleaya cordata in AC+A-2+P+U group were significantly increased by 10.67%?45.76%,26.87%?92.02% and61.99%?159.98%,respectively,and the contents of the total superoxide dismutase(T-SOD)and catalase(CAT)were increased by 48%?133% and14.81%?17.71%,respectively,and the oxalic acid was increased by13.04%?157.09%.Compared with the A-2+P+U and P+U groups,the bioavailable uranium in soil in AC+A-2+P+U group was increased by 12.5%and 61.54%,respectively.In the AC+A-2+P+U groups,there were a large number of Fusarium fungi and Acidobacteria in rhizosphere soil,and the proportion of Fusarium fungi was the highest.Compared with AC+P+U,A-2+P+U,P+U,and A-2+U groups,the proportion of Fusarium fungi in AC+A-2+P+U group was increased by 16.67%,81.03%,299.23% and374.47%,respectively.The mechanism by which AC and A-2 coupling enhanced the remediation may be that AC could improve the mobility of uranium in soil,increase the contact between plant roots and uranium,and promote the enrichment of uranium by Macleaya cordata,that AC could stimulate the physiological activity of Macleaya cordata,increase the biomass of Macleaya cordata,improve the activity of antioxidant enzymes,and enhance the tolerance of Macleaya cordata to uranium,and that AC could stimulate the growth of Fusarium fungi and Acidobacteria,increase their proportion,produce a large number of organic acids which can form chelates with uranium,reduce the stress of uranium on plants,increase the proportion of available states of uranium,and promote the enrichment of uranium by Macleaya cordata.This research showed that AC and A-2 coupling exhibited a significant enhancement effect on the remediation of uranium contaminated soil by Macleaya cordata,and there coupling was a promising enhancement method.