The Investigation Of Heavy Metals In Two Regions Soils Of Zhengzhou City Ang The Analysis Of Copper And Chromium

Soil is the base for the growth of plants and mankind, the stand or fall of soil environmental quality will directly affect the production and development of human life; the extent of soil pollution will affect the output and the mass of primary products. Heavy metal contaminated is one of the major pollution types of soil ecosystem, and the soil is also an important accumulation library for heavy metals. Heavy metals in soil can be absorbed and accumulated the number of times by plants and animals through food chain. Heavy metal pollution has been paid a high degree attention. But with the in-depth study of migration and accumulation of heavy metals behavior, the full amount of heavy metals assess the soil pollution which can not really represent the potential ecological hazards and post-contamination. The results provided by a number of conduct-based definition of heavy metals extraction technology have a good correlation exists between the nature of soil bio-availability, toxicity and migration, ect, which greatly promotes the study of the form analysis of heavy metals in soil. In addition, the method for the morphological analysis of heavy metals in the soil has no uniform definitions and standards. Five-step sequential extraction method proposed by Tessier is the common used method for the form analysis of heavy metals in the soil.In this paper, the five-step sequential extraction method are used to analysis the forms of Pb,Cd,Cu,Zn and Mn in the soil of Henan Academy of Agricultural Science and Zhengzhou High-tech Development Zone. On the basis of extensive literature, we established solvent extraction-flame atomic absorption spectrophotometry in different forms of soil copper and chromium in new ways. Main research contents summarized as follows:(1) The five-step sequential extraction method are used to analysis the forms of Pb,Cd,Cu,Zn and Mn in the soil of Henan Academy of Agricultural Science and Zhengzhou High-tech Development Zone.(2) Different forms of soil copper can be determined by solvent extraction-flame atomic absorption spectrophotometry, in which DPC is used as complexing agent, CTMAB is used as photosensitizing agent, MIBK is used as the extracting agent.Cu(Ⅱ)can form stable complexes with DPC, which can be extracted quantitatively by MIBK and determined directly by flame atomic absorption spectrophotometer. CTMAB can enhance the optical signal.The method's detection limit is 9.67 ng·mL-1, the relative standard deviation was 4.8%, the recovery yield of standard addition ranges from 90% to 110%. The result shows that this method is simple, rapid and accurate, and the most common ion pair does not interfere with the determination of copper in soil. For the interference ions, ascorbic acid can effectively eliminate the interference.(3) Different forms of soil chromium can be determined by solvent extraction-flame atomic absorption spectrophotometry, in which aluminon is used as complexing agent, MIBK is used as the extracting agent.Cr(VI) can form stable complexes with aluminon, which can be extracted quantitatively by MIBK and determined directly by flame atomic absorption spectrophotometer. The method's detection limit is 8.20 ng·mL-1, the relative standard deviation was 3.2%, the recovery yield of standard addition ranges from 89% to 110%. The result shows that this method is simple, rapid and accurate, and the most common ion pair does not interfere with the determination of chromium in soil. Before the law. is used to determine the samples, the sample pH is adjustment to a range using ammonia water, so the magnesium, aluminum and other metals can be precipitated and filtered in advance, which also can eliminate the matrix interference.