| It is estimated that thousands of sites in our country have been polluted with heavy metals. It results in huge losing on ecosystem and economy, and threatens health of the people. It is no time to delay dealing with and remedying the contaminated soils. In Europe and America, there are quiet great progresses in the research of soil washing and soil amending remediation technology. In our country, researches on these technologies are just on beginning. Basing on the research ago, choosing soil samples from three sites including Xiangtan manganese mine, Chejiang copper mine and Yongzhou copper mine, we investigated the application of soil washing and soil amending remediation technology in heavy metal contaminated soils.The results showed that soil washing employing physical separation and chemical extraction could markedly reduce the degree of pollution. In experiment, the maximal removals of heavy metals from the three soil samples reached 79.74% of Pb, 59.62% of Cd, 57.81% of Cu, 43.06% of Zn and 52.23% of Mn, respectively. The removal of heavy metals could be enhanced through the optimized technology design. By batch and orthogonal experiments, the researches analyzed the factors that influenced the removal efficiencies of heavy metals. The results demonstrate that many factors, such as, soil characters (including soil texture, soil pH, content of soil organic matter), parameter of the washing technology (including the kind and concentration of extractant, extracting time, the ratio of liquid to solid) and the characters of heavy metals in soil (including the kind of metals and the metal existing form fractions), influenced the removal of heavy metals. EDTA was an effective metal extractant, the maximal removals of heavy metals reached 79.74% of Pb, 59.62% of Cd, 57.81% of Cu, 40.40%of Zn and 43.30% of Mn, respectively, but it was not adapted in the remediation of agricultural soil for its high cost and destroys to soil. Citric acid was effective at removing Pb, Cd and Mn in the contaminated soil, the maximal removal reached 66.70% of Pb, 53.85% of Cd and 52.23% of Mn, and could apply in remedying Xiangtan manganese mine contaminated tailing soils for its low price. Oxalate was effective at removing Cu and Zn, the maximal removal reached 55.08% of Cu and 43.06% of Zn, but invalid in removing Pb and Cd, and could apply in remedying the single Cu or Zn contaminated soil. In the experiment, heavy metalsin the clay soils are more difficultly removed for its power binding strength, so it was not adapt for remediation by soil washing technology. Humic acids in soil influenced the availability of heavy metal, and then influenced the removal of heavy metal. In addition, the research found that biosurfactant surfactin could be used as additive of general extractant to enhanced heavy metal removal efficiencies. For its effectiveness and high cost, soil washing technology could apply in the remediation of the area that was serious contaminated by heavy metals and the area that had acute toxicity, or the area that could not be successfully remedied by biology remediation.The paper researched the influence of humic acids on the existing form of heavy metals in Yongzhou copper mine and Chejiang copper mine contaminated tailing soils. The results showed that humic acids was effective at immobilizing Pb and Cd in the soil samples in the form of residual fractions or organic matter fractions, which were not availability for ecosystem. The existing form of Cu and Zn was little affected by humic acids, the appending of humic acids accelerated the transfer of heavy metals from slag to soil grains, and the pollution index of soil grains was enhanced; humic acids is likely to reduce the soil danger index, but the precondition is that the other factors have little influence on the chemical form transformation. The results proved that whether organic matters can amend the heavy metals contaminated tailing soils mainly lies on the physical and chemic properties of the tailing soils, and...
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