Research On Phytoremediation For Radioactive Sr Contaminated Soils

Radioactive contaminated soil not only wastes land resources,but also has potential internal irradiation hazards through the biological chain of human beings.At present,the most advantageous method for the remediation of large areas of low-level radioactive contaminated soil is phytoremediation.Vegetable crops generally grow fast,have short life cycle,and have rich experience of a large area of artificial cultivation and control and prevention of pest and disease,which makes vegetable crops especially suitable to be a hyperaccumulator.In this paper,the Sr enriched vegetable crops were screened by pot culture experiment in greenhouse,and shepherd’s purse with potential for enrichment of Sr was chosen to explore the mechanism of Sr enrichment,which could be used to provide basis for phytoremediation research and application of large area of lowlevel radioactive contaminated soil.The main results are as follows:(1)According to the plants’ growth response to the Sr concentrations of soil,plants can be divided into three types: plants whose growth depressed by high Sr concentrations,plants whose growth promoted by high Sr concentrations,and plants not sensitive to Sr.(2)It was confirmed that the plants with higher Ca content had stronger capability to enrich Sr,and the transport coefficient was related to soil properties.(3)Kidney bean has the potential to become Sr hyperaccumulator.(4)Shepherd’s purse is a hyperaccumulator of Sr,and its biomass and Sr transport coefficient generally increased first and then decreased with the increase of the Sr concentration of soil,while the Sr content,Sr enrichment coefficient and the total amount of Sr enrichment generally had an increasing trend;(5)The absorption of Sr and Ca by shepherd’s purse may have a certain relationship,and further study is needed to figure it out.(6)The transplanting of shepherd’s purse generally had no effect on the growth and Sr enrichment rule of shepherd’s purse.After the same period of time,transplanted shepherd’s purse could produce much more biomass than direct-seeded shepherd’s purse,and thus could enrich much more Sr.