| Mining is China's basic industries, and also has an important position and role in the economic and social development. Now Heavy metal pollution is one of the most important research topics in China and the world. Phytoremediation is considered to be the most promising approaches to reduce tailings environmental hazards, Chelating agent EDTA on the target metal in the soil have a high chelation efficiency, and its stability in the environment and less toxic to the organisms, is now the most commonly used. We designed the potting experiment on the based of field experiment in Xiangtan, Hunan province. Through pot culture method, in July2009, Xiangtan manganese mine and natural soil1:1after mixing soil as potted soil, according to the EDTA exerts a volume set7treatment:0(CK),0.25mmol/kG,0.5mmol/kg,1mmol/kg,2mmol/kg,4mmol/kg,8mmol/kg,4repeat. Soil applied after each quarter with cutting ring sampling, after5quarters, the stump extraction plants indoor heavy metal content analysis, taking the average value as the final analysis results.The result shows:(1) Koelreuteria paniculata seedlings has a strong heavy metal tolerance, doing well during the entire experiment, there was no die. Has maintained a growth trend, the first90d and one quarter of the fastest growing, plant height and an average increase of2.13-2.89times, Koelreuteria paniculata species of the ecological habits; Luan imposed by the tree in EDTA the amount of high concentration (1-8mmol/kg) pot is better than the low concentration (0.25mmol/kg,0.5mmol/kg) potted plant.(2) EDTA improve the desorption capacity of heavy metals in soil. Different EDTA soil heavy metal content of Extreme time difference of Cd shortest time, a quarter to the highest value, Cu and Mn in order to achieve three quarters, while Pb and Zn were the longest in the360d later in order to make the highest heavy metal content in the soil; high concentration of soil heavy metal content of EDTA low concentration higher than0.25mmol/kg or0.5mmol/kg EDTA heavy metal content in the soil the highest value, while in the high concentration of2mmol/kg or4mmol/kg of EDTA detected in the soil heavy metal content is lower than the same period the content of other groups.(3) EDTA promotes Koelreuteria paniculata absorbing heavy metals. Either control or experimental group, and Koelreuteria paniculata seedlings to absorb and the number of accumulation of heavy metals are the roots> leaves> stems, leaves than that in roots of the trend over time. The low concentration of EDTA added (0-1mmol/kg) to promote the absorption of the five kinds of heavy metals in root and stem, leaf absorption of Pb and Zn in the high concentration of EDTA added (2-8mmol/kg) to promote leaf of Cu Mn and Cd absorption.(4) EDTA improve the capacity of enrichment plants and the roots of the transfer of heavy metals. Koelreuteria paniculata is not super-enrichment plants, EDTA increased Koelreuteria paniculata for Cu, Mn, Cd, Pb and Zn enrichment capability is not obvious overall enrichment factor of Cu> Zn> Pb> Cd> Mn, compared to the control, the bioconcentration coefficient increased by only about0.1; changes in the plant transfer coefficient and the rate of accumulation is consistent, increases with increasing concentration of8mmol/kg of EDTA to impose the amount of plant roots transfer, the transfer coefficient greater than1. Comprehensive considerations, applied to the potting soil of EDTA Luan tree restoration effect of Pb enrichment ability to Cu strongest, the strongest of Cd transport capacity. |
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