Experimental Study On Remediation Of Mercury Polluted Sites Using Miscanthus Sinensis

The restoration of mercury-contaminated sites is an urgent and hard task.Phytoremediation technology has attracted more and more attention because of its environmental friendliness.Plant extraction is considered to be the most promising technology in phytoremediation.Ideal plants which are used for plant extraction should be tolerant,accumulative and sufficient in biomass.In this study,the tolerance and phytoremediation potential of Miscanthus and its effects on microbial community and nutrients in rhizosphere soil were studied by pot experiment under eight concentration gradients(with soil mercury concentration of 11.505 mg·kg-1 to 705.681 mg·kg-1)and a control experiment.The effects of nutrients and mercury forms were evaluated.The changes of external form,biomass,plant height,chlorophyll content and SOD activity indicated that Miscanthus had strong tolerance to soil mercury exposure,and the medium and low concentration of mercury had little impact on Miscanthus.The exposure to soil mercury content was as high as 705.681 mg·kg-1,although the organism the amount is inhibited,but it can also grow.The mercury content in shoots and roots reached the maximum at 183.262 mg·kg-1 and 398.08 mg·kg-1,respectively,which was 329.96 mg·kg-1 and 298.064 mg·kg-1.The bioconcentration of mercury is close to or greater than 1,when Miscanthus was exposed to soil mercury down to 183.262 mg·kg-1.The TF are close to or greater than 1 under different concentration treatments.It demonstrates that Miscanthus can be applied to plant extraction.The cultivation of Miscanthus can change the microbial community structure,enhance microbial respiration,and increase the diversity and abundance of soil microbial communities.But it may cause potential loss of soil nitrogen and phosphorus in the early and middle stages of its growth.The exch-Hg and orga-Hg have great influence on the mercury uptake by Miscanthus.In summary,this study shows that Miscanthus is a promising energy crop that combine biofuel production and mercury phytoremediation.It has environmental and economic benefits.