Research On Heavy Metal Enrichment Characteristics Of Several Plants And Effects Of Soil Remediation

With the development of industry,the problems caused by heavy metal pollution in soil gradually enters the public's field of vision.These series of environmental problems and quality problems of agricultural products are increasingly prominent,so it is particularly important to carry out remediation research on heavy metal contaminated soil.In recent years,phytoremediation has gradually become an important measure for remediation of contaminated soil due to its advantages of low cost,environmental friendliness and simple operation.Based on the contaminated farmland soil in Anhui province,this paper selects four plants of tall fescue,ryegrass,Rumex acetosa and Sedum aizoon as experimental materials to analyze the copper and cadmium enrichment and transport capacity of plants through intercropping mode strengthening and combined chemical inducer strengthening,explores the feasibility of strengthening the phytoremediation of copper and cadmium contaminated soil by the two methods,and provides evidence for phytoremediation of copper and cadmium contaminated soil.The main research results obtained in this paper are as follows:(1)The growth of the four plants in copper-cadmium contaminated soil has no obvious damage characteristics and has strong tolerance.Compared with the overground part,the content of heavy metals in plant roots is higher.Judging from the enrichment coefficient,ryegrass and tall fescue have better enrichment effect on Cd,while Rumex acetosa and Sedum aizoon have better enrichment effect on Cu.(2)Compared with monoculture,the biomass of the two plants that interacting in intercropping mode showed a downward trend due to the competition of nutrients.However,intercropping can strength the absorption of heavy metals Cu and Cd by ryegrass and Rumex acetosa,enhance the enrichment ability of heavy metals in plants,and improve the remediation efficiency of Cu and Cd contaminated soil.(3)Under the static activation simulation test,compared with the reinforcement without chemical activator,the pH of the soil with three different chemical activators decreased,and the content of acid soluble state in the soil generally increased first and then decreased,while the content of other forms of heavy metals showed no significant change trend.Comprehensive analysis of different application concentrations of chemical activators shows that 5mmol/L chemical activator solution has the best activation effect on heavy metals Cu and Cd.(4)Compared with no chemical activator,the soil available state content increased after 5mmol/L chemical activator was applied alone,and the Cu and Cd contents in tall fescue and Sedum aizoon showed an upward trend.The enrichment coefficient of Cu and Cd in plants increased,but the change trend of transfer coefficient was not significant.Three chemical activators have certain effects on strengthening phytoremediation,but after the application of EDTA tall fescue and Sedum aizoon have the most significant absorption effects on heavy metals Cu and Cd.