Research Of Chemistry-plant Combined Remediation Of Heavy Metals In Agricultural Soil Of Tongguan

Soil is not only the basis for human survival and development, but also an important part of the ecological environment. April 17, 2014, the Chinese Ministry of Environmental Protection, Land and Resources jointly issued a nationwide survey of soil pollution bulletin shows that Chinese soil pollutants exceeding the rate of 16.1 percent points, accounting for 82.8 percent of heavy metal pollution.This experiment is based on a farmland contaminated by heavy metals.Contaminated soil were repaired through the use of fly ash and other engineering means, and planted Sliphium Perfoliatum, sunflower, Bidens pilosa, Amaranthus paniculatus, Lolium perenne, Stramonium six kinds of herbs and a woody plant Germany poplar increased the effectiveness of contaminated soil remediation.Finally,Bioremediation potential was discussed. The results show that:(1) Soil test area of Cd pollution is most serious, followed by Hg and Pb. The average content of the Cd and Hg is 3.70mg/kg、1.64mg/kg,is 6.17 and 1.64 times of soil environmental quality standards secondary standard values.(2) The average contents of TCLP-extractable Cd, Pb and Hg is 1.743mg/kg、9.45mg/kg and 0.69×10-3mg/kg,contents of Cd and Pb were 3.5 times and 1.9 times of international standards values, TCLP-extractable of Hg is very low. Available contents of heavy metals account for total amount is different, and the highest proportion is Cd, the average is 47.10%, Pb is 8.07% and Hg is 0.42%. This suggests that Cd in the study area has a high mobility and bioavailability.(3)After immobilized by fly ash, available content of Hg, Cd and Pb was reduced 28.57%, 24.36% and 31.83%. Contents of Pb and Hg is substantially reduced. Available Content of Cd is still very high.It need to further remediation by phytoremediation.(4) Amaranthus paniculatus and Bidens pilosa intercropped with Germany Poplar have better results in repairing Cd. It required 6a and 7.8a to repair if mowing 3 stubble a year, respectively. On the basis of fly ash,Amaranthus paniculatus and Bidens pilosa intercropped with Germany Poplar need 4a and 5.1a, respectively.