The Study About Phytoremediation And Effects Of Heavy Metal Pollution On The Activity Of Soil Enzyme

In this paper,the local soil environment of Xinxiang City was taken as the research object to have a study at soil enzyme activity,and then evaluated the status of heavy metal pollution in the soil around the local industrial area.The plants which grow in the polluted area were preliminarily selected.Based on the evaluation and screening results,the effects of phytoremediation were studied.Urease,sucrase and catalase were chosen as the research objects,then had a study about the activities of enzymes in the soil where Hylotelephium erythrostictum(Miq.)H.Ohba grown in.Results showed that under single Cd-contaminated soil,the activity of the sucrase and catalase were all inhibited,and low concentration of Cd could promote the activity of urease in soil,while high concentration of Cd had an inhibition on it.Under single Zn-contaminated soil,low concentration of Zn could promote the activity of urease,sucrase and catalase,while high concentration of Zn could inhibit it.Under the combined pollution of Cd and Zn,with the increase of contaminated concentration,the inhibition of urease gradually increased,and the activities of sucrase and catalase firstly promoted and then inhibited.Finally,through comprehensive comparison,the effect on the activity of three enzymes were urease> catalase> sucrase.The soil around an industrial zone of Xinxiang City was surveyed and sampled.Then the species content and existing forms of heavy metals in soil were analyzed,and the status of heavy metal pollution in the area was evaluated.The results showed that all the soil samples collected in this area were over-standard for Cd and Ni,there was no over-standard phenomenon in Pb,Cr,Cu,Zn and As.The Cd and Ni in soil mainly existed as Fe-Mn compounds,which were easily absorbed and utilized by plants.The pollution index method,potential ecological risk index method and geo-accumulation index method showed that the soil in this area was seriously polluted by Cd.16 species of plants and their rhizosphere soil in an abandoned cadmium oxide plant in the area were sampled,then analyzed and compared from the aspect of the growth of plants,the accumulation of Cd,TF and BCF of these plants.The results showed that Chenopodium serotinum L.was more suitable as a remediation plant for the contaminated soil with higher cadmium concentration and Hylotelephium erythrostictum(Miq.)H.Ohba was more suitable for the cadmium contaminated soil with low concentration.Hylotelephium erythrostictum(Miq.)H.Ohba was selected as the research object based on the cadmium concentration of the farming soil in Xinxiang City.Then different Cd-contaminated treatment groups and Cd and Zn compound pollution treatment groups were set up under the laboratory for further exploration about the growth status and the enrichment characteristics of Hylotelephium erythrostictum(Miq.)H.Ohba.The results showed that low cadmium concentration could promote the growth of Hylotelephium erythrostictum(Miq.)H.Ohba,and the high could inhibit it.On the Cd-contaminated treatment groups only,the accumulation of Hylotelephium erythrostictum(Miq.)H.Ohba was increasing with the increase of cadmium concentration,the value of TF and BCF of all the groups were over 1.It reflected that Hylotelephium erythrostictum(Miq.)H.Ohba had a strong ability of transportation and Cd enrichment,which showed that it had the potential of becoming the hyper-accumulator of Cd.Under Cd and Zn combined pollution,with the increase of Cd concentration,the height,root length,dry weight of aboveground and underground parts of plants were gradually decreasing.On the contrary,there was the same trend.Compared with the corresponding single Cd-contaminated treatment groups,the addition of Zn increased the accumulation of Cd.