Identification Of Heavy Metal Hyperaccumulators And Relevant Processes Of Contaminated Soil Phytoremediation

To screen out a series of ideal hyperaccumulators that can effectively remedy contaminated soils by heavy metals is the main groundwork of phytoremediation engineering and the first step of its commercial application on a large scale, which is also front field of contaminated environment remediation. In view of that the amount of discovered hyperaccumulators and their hyperaccumulated the types of heavy metals are short at present, the identification of hyperaccumulators and some strengthen measures were carried by using pot-culture, block method and sample-analyze experiment, and the basic conception, theory, manner and relevant enhancement mechanism of phytoremediation were systematically summarized based on published documents, the results as below:(1) The characteristics that critical concentration, translation, tolerance and accumulation coefficient are indispensable properties of hyperaccumulators.(2) Solanum nigrum L. and Rorippa globoga(Turcz.) Thell. are Cd hyperaccumulators, and the concentrations of Cd accumulated in stems and leaves were 103.80mg/kg,124.57mg/kg and 107.70mg/kg,150.10mg/kg respectively on the condition of 25mg/kg Cd was added. Cd is mainly distributed in stems and leaves of the plants, but they could not hyperaccumulate Pb, Cu or Zn simultaneously.(3) The remediation efficiency of phytoextraction could be enhanced 35.7%～97.0% and 43.0%～75.0% through added chicken manure to soil and the multiple cropping that transplant hyperaccumulators after them be cropped at their flowering stage.(4) It will make a great breakthrough in the identification of hyperaccumulators based on weed species.(5) The field pot-culture experiment should be a new tentative method to screen out hyperaccumulative species in view of its obvious advantages such as simple operation, low cost and so on.(6) It is possible that hyperaccumulators would be found in an unpolluted area though documented hyperaccumulators discovered in contaminated sites.(7) It was suggested that the adoption of modernization agriculture technology will be a short cut to the commercial apply of phytoremediation to heavy metals.