Studies On Phytoremediation Of Rare-earth Mined Area

The north-east of Guangdong Province’s mountains are rich of rare earth resources, alsothe main distribution areas and producing areas of weathered crust-eluvial rare-earth mine.Rare earth resources development and utilization contributed to the development of the localeconomy, but also led to environmental problems and ecological problems. In this study,taking815rare earth mine in Heping County town as an example, adopt to landfilling theOrganic and planting in Soil improvement, either in ecological remediation. Compared withvegetation succession, the soil physical and chemical properties,16s rDNA of Bacteria andBacterial Diversity of SRAP. Then make an systematic evaluation. The study results are thefollowing:1. We adopt Organic landfilling and ecological restoration to improve soil in the study.The maize, vetiver grass, crab grass and other plant can bloom and bear in thereclamation-area. In3year restoration, the plants of Artificial and wild are normal grow andsuccess. After investigation, the reclamation-area has28species. It is said that, althoughphytoremediation is short, the effect of restoration is obvious.2.compare with before mining,soil fertility of after mining is much lower,contents ofN、p、k are in very low level,With the restoration,the soil fertility increase to medium level,the total nitrogen、available phosphorus and available potassium is1794.6mg/Kg、44.42mg/Kg、140.13mg/Kg respectively. In addition water content increase every years, soil it’s28.14%. In0～20cm of the3year restoration soil when it’s18.22%in the soil after mining.Besides,the soil bulk density decreased year by year,the soil bulk density is1.33aftermining,and it’s decreased to1.21in3year restoration. in general,the change of Soil fertilityand soil physical properties showed that soil physicochemical properties improved.3. The microbial biomass of the soil is increase year by year after restoration, Themicrobial biomass respective is before mining4000cfu/g、after mining500cfu/g、1yearrestoration1500cfu/g、2year restoration5900cfu/g, and last3year restoration8700cfu/g.The microbial biomass of3year restoration is much more than soil before mining. UsingSRAP molecular marker to analyze polymorphism of the soil bacteria, PPL and PIC of the soil bacteria show that the polymorphism is increase every year. PIC of3year restoration is0.9303, and its PPL is100%.4. Sequencing and analyzing with the bacterium’s16s rDNA, and make a Blastanalysis in NCBI GeneBank, revealing the sample sequencing of before mining has2genus(Arthrobacter、 Bacillus), it is1genus in soli after mining and1yearrestoration(Brevibacillus), after2、3years restoration,there are4(Bacillus、Lysinibacillus、Bacterium、Sinorhizobium) and5(Paenibacillus、Bacillus、Solibacillus、Bacterium andSinorhizobium) genus in the soil. It showed that advantage of the bacteria is changing, thespecies and diversity of bacteria is increasing. The results are the same as the SRAP diversityanalysis.The restoration method has been got preliminary application in815rare earth inGuangdong Heyuan. In the study, adopting to evaluate the effect of ecological restorationmethods for rare earth mining Comprehensively. The results show that the land bettermentmethod is obvious and uncomplicated. It is able to make rare earth mining to achieve secondploughing either. So it could provide technical support for the rare earth mine wastelandphytoremediation.