Study Of Spatial Distribution And The Migration Transformation Rule Of Heavy Metals Contents In Soil Of Tongliao Sewage Irrigation Region

Currently, the heavy metals pollution caused by irrigation is paid more and more attention. The heavy metals will threaten human health through "soil-plant-food" chain. So study the migration and transformation of heavy metals is significant.In this paper, as well as investigated the heavy metals in the wastewater-irrigated area of, Tongliao, we study the transformation and migration of heavy metals in the soil-plants system, with pot experiment and soil column, and the following conclusions:(1) Research on the large-scale sewage-irrigation area, Tongliao, with a total of 95 surface soil samples along the irrigation channel, monitor heavy metals of Cd, Cr, Hg, Pb, As, Ni, Cu and Zn. The results showed that:7 sample sites of Hg and 5 sample sites of Cd are all exceeded secondary standard value of "soil environmental quality standard".(2) To analysis spatial distribution of heavy metal content of Kongjia coutry which irrigated with waste water for a long time. Using plum distribution method with a total of 39 sampling points, through kriging analysis, rendering the contour map of concentration of the monitoring project, the results showed that:the contents of As, Cu, Pb and Zn is higher along the irrigation channels, while Hg, Cr and Cd do not. Besides, 1 sample point of Cd and 2 sample points of Hg were exceeded secondary standard value of "soil environmental quality standard".(3) In the laboratory soil column experiment, irrigating the soil column with the concentration of water, wastewater treatment plant effluent, a low concentration of heavy metals (Cr, Cu, Hg), a high concentrations of heavy metals, respectively, results showed that it has a maximum value of heavy metals between 35cm～55cm soil. The content of Cr and Cu decreased with soil depth, while Hg do not.(4) In the outdoor pot experiment, corn couldn't grow normally under the polluted soil by different content Cr of 100,200 and 300 mg/kg soil. The distribution of heavy metal Cr in corn is:root> leaf> stem> grain. Irrigated by different concentrations of Cd (respectively 0,1,2.5,5,10 mg/L), the distribution of heavy metal Cd in corn is:root> stem> leaf> grain.