Experimental Study Phytoremediation On Contamination Of The Uranium Ions Outflow From The Decommissioned Uranium Mining And Metallurgy Teservior

In recent years, more and more uranium mining and metall urgy tailings reservoir is retired or to be retired, decommissioned uraniu m mining and metallurgy reservoirs have a serious impact on environment, the govermence of uranium pollution control after the reteirment is regarded as a urgent work. The present method of uranium tailings pollution governance mainly divided into physical method, chemical method and phytoremediation. Compared with physical method and chemical method, phytoremediation has lowcost, small disturbance to the soil, the characteristics of second pollution, the use of uranium mining and metallurgy tailing phytoremediation of contaminated after retirement has become a hotspot at home and abroad. The utilization of phytoremediation on contamination of the uranium ions outflow from the decommissioned uranium tailings impoundment should take into a number of factors because the limitations of phytoremediation technology and the complexity of uranium tailings reserviors pollution. In this paper, through the invest,Screening of uranium enrichment plant, problems related to experimental study on Phytoremediation of uranium tailings, and ultimately to provide a scientific basis for the uranium mine and mill tailings pollution phytoremediation applications after retirement. The specific work is as follows:(1)The study of uranium ions outflow from uranium mining and metallury reservior migrations shows that the uranium ions eventually accumulated in the soil. analysis of the factors influencing the plant remediation of uranium contaminated soil effects, including uranium ion state, physical and chemical properties of soil, plant species, the external conditions. Investigation of tailing dam decommissioning uranium mining and metallurgy of soil physical and chemical properties, do indepth understanding of the existing form, distribution of uranium mining and metallurgy uranium tailings ion in retirement. The survey found that the uranium mine and mill tailings pollution is serious in China, pollution of soil for tailings dam seepage and other reasons, the soil p H value between 5~7, soil acidity, uranium exists mainly in the uranyl ion or hydroxyl complexes, pollution depth is about 30 cm, the use of phytoremediation of uranium tailing out of uranium ion pollution in soil the feasibility of. At the same time the uranium tailings contaminated soil containing heavy metal ions, the uranium tailings contaminated soil is a serious radioactive-heavy metal combined pollution, phytoremediation of uranium tailings out of uranium ion pollution soil needs to consider the tolerance of plants to heavy metal ions.(2)The investigation of plant resources of uranium tailings impoundment, the screening can be used to repair the uranium tailings of uranium ion pollution plants. The survey shows plant resources of uranium mining and metallurgy mine tailings contaminated area rich in herbs, which accounted for 80%, accounting for about 20% of woody plants. Among them, Goosegrass, Polygonum hydropiper L., Setaria viridis, Digitaria Sanguinalis is a dominant plant Bidens bipinnata, is also a uranium enrichment capability of plants, these plants can be used for the uranium tailings pollution.(3)In this paper with spinach, chinese cabbage and water spinach as testing material, study the effect of uranium concentration on the germination and growth of three plants. The result shows that uranium concentration has little effect on the germination of plants, but with the increasement of concentration of uranium, plant grow status is different, the mortality rates of Chinese cabbage increases significantly with the icreasing of uranium concentration in two weeks, the mortality of water spinach was less than 10%. Experimental study on 0, 50, 75, 100, 250.0mg/kg concentration of uranium in the soil, the ability of enrichment of uranium of three plants, the results show that compared with chinese cabbage and water spincach, the ability enrichment of uranium of spinach is stronger, under the condition of uranium concentration of 100.0mg/kg, the uranium content in the aerial part of spinach wers187mg/kg, the underground part wers 313mg/kg, under the uranium concentration of 250.0mg/kg in soil a Chinese cabbage all died. Experimental study on the concentration of uranium 100.0mg/kg, copper concentration of 100.0mg/kg in soil, plant monocultures and mixed planting of uranium enrichment plant, the experimental results show that the three kinds of plants in the copper ions under the action of uranium enrichment capacity decreased, and using two kinds of different plants grow better mixing effect of enriched uranium,so the use different plant mixed remediate uranium tailings impoundment polutted soil is feasible. Although fertilization will increase plant biomas, may result in decreased the ability of uranium accumulation of plants.