The Copper Enrichment Characteristics And Adaptation Of Wild Ramie For Phytoremediation Of Copper Mine Tailings

Abandoned lands of metal mines,especially for the tailings,have limiting factors such as high level of heavy metals and poor nutrients for plants to help restore.Phytoremediation and amendment substances on tailing matrix are common ecological recovery techniques at present.Screening remediation plants which can resist heavy metal pollution and barren for tailings is important for ecological restoration.Ramie has strong adaptability,strong resistance to drought,barren,plant diseases and insect pests.The ground can be covered for a long time,root of wild ramie is very strong.It can help improve the solid ability and water conservation of the soil.It is a good plant for environmental recovery.Due to the long-term growth in relatively high concentrations of heavy metals in mining area,wild ramie has strong resistance to heavy metal CuThrough the field investigation of the settled natural wild ramie in Hubei Daye copper mining,found that the wild ramie can grow well while the copper concentration in mine soil are as high as 9262 mg/kg.It indicated that wild ramie has a very high copper resistance.In this trial we determined the copper content in leaves,skin,bone and root of wild ramie by atomic absorption spectrometer to study the characteristics of enrichment and transfer of heavy metals of wild ramie.It was concluded that trend of Cu content in different parts of ramie was as follows:root>skin>bone>leaf.The copper enrichment concentration of its roots can be up to 1056 mg/kg.The copper concentration of skin can be up to 452.99 mg/kg,while Cu content in the leaves is very low.Due to the different background and individual differences between ramie plants,Cu enrichment and transfer of wild ramie is different,the root accumulate most amount of Cu,suppresses the transfer of Cu to the ground.Enrichment coefficient and transfer coefficient of wild ramie do not conform to the condition of heavy metal hyperaccumulation plant,the highest transfer coefficient is 0.86.In addition,we found that the wild ramie can grow normally in the Tonglv Mount by potted plant experiments,while ramie collected from the campus of Hubei University in the pollution-free soil cannot survive.In order to restore the copper tailings of Tonglv Mount and make wild ramie play a better role in the tailings recovery process,we tried to improve the tailing soil in the test.Wild ramie were planted in pots contained the copper tailings and non-polluted soil in different mixing proportion(1:0,1:2,1:1,2:1 and 1:0 mix ratio).Three months later,we studied the influence on the growth of the wild ramie and analyzed the biomass,photosynthesis and chlorophyll,MAD,activity of CAT,POD and SOD.The result showed that the wild ramie can grow best in the mixed soil of ratio of 1:1 according to the comprehensive comparative analysis.The biomass was 2.34 times of control soil,the amount of heavy metal enrichment was 1.9 times of control soil.Due to the lack of organics and plant nutrients of the tailings of soil,we add protein peptide derived from the sludge as amendment substances to the copper tailing soil to promote the growth of the wild ramie and help pollution repair.By studying the influence of different concentration of protein peptide on the growth of wild ramie and testing physiological indexes of the wild ramie in pots.We found that it can promote the growth of ramie obviously when the protein peptide concentration are low at 1 ml/kg and 2 ml/kg,compared with the controls.When the concentration of sludge protein is 2 ml/kg,the enrichment of Cu can be 46.4 ?g for every pot,2.5 times as the control group.The biomass of the experimental group was 2.3 times of the control group,the amount of heavy metal enrichment was 2.5 times of control soil.While relatively high concentration of protein peptide can inhibit the growth of ramie at 5 ml/kg.And tailing soil with low concentation of protein peptide has higher level of available copper than the control and high concentration of protein peptide added tailing soil.Meanwhile,the higher the concentration of protein peptide was in the tailing soil,the more the tailing microbial content was tested in the soil,it can be 15.4 times of the control.Through the experiment preliminary exploration,we found that wild ramie has strong Cu tolerance ability adaptability to copper tail recovery.Although Cu enrichment of aerial part wild ramie is not very high,when take the advantages of wild ramie into consideration,it can be a pioneer plant and play a better role in tail recovery and plant restoration of the copper mine tailing soil.