| In this paper, we studied the chemical speciation, the distribution and migration behaviours of heavy metal in the mine tailingsand and nearby river sediment in the Pangu tungsten mine yudou county Jiangxi province. Through laboratory analysis, we reached the following conclusions.1. Correlation analysized between the physical and chemical properties of the mine tailings and total heavy metals of Pangu tungsten mine indicated:Tailings moisture is the most in new tailings and is the lowest in artificial vegetation to repair30end of sand. Tailings moisture is favorable toward the further migration of Cr, but is not conducive to the migration of Pb and Cu and has little effect on other heavy metals. The lower pH is more favor for the further migration and transformation of heavy metals as Cu, Mn, Mo, Ni, Pb, W and Zn in tailings. Organic matter has a strong adsorption capacity of heavy metal Cr in tailings.2. The following is the vertical distribution law of heavy metals in the tailings. In the50s and60s of last century, the content of As, W, Mn is the most in the0-20cm surface tailings and Cu is rich in the60-80cm layer and Zn is rich in the80-100cm layer. In tailings repaired for30years, the content of heavy metals is significantly reduced in the0-100cm layer. This is the role of surface runoff, stormwater infiltration and plant and lead to heavy metal enrichment of Zn in the80-100cm layer. In tailings repaired for15and5years, the variation of heavy metals is little. The content of Zn has an initial drop as the depth increases and the minimum is found in20-40cm layer while several other heavy metals did not significantly change. In the new tailings, the content of As, Mn, Mo and Zn is the most in the0-20cm surface and the W has enrichment at20-40cm layer.3. It is the distribution law of heavy metals in the same depth in different years of tailings. In0-20cm layer, the content of Mo in new tailings and Mn in artificial vegetation repaired for30years of tailings is the most. The change in the20-40cm and0-20cm surface of each heavy metal is little, but he content is slightly reduced in20-40cm surface. In40-60cm layer, over time W, As, Cu, Pb and other heavy metals fall after rise while Mo decreased as the years further. In60-80cm layer, Zn, W, Mn, As and Cu increased first and then reduced with the age. Mo is the most abundant in new tailings. In80-100cm layer, heavy metals of Zn, W, As and Pb, Cu, etc fall after rise while Mo decreased over time.4. Toxic effects of heavy metals in the environment mainly depend on heavy metals chemical speciation. Heavy metals of As, Cr, Ni, W mainly exist in the foim of residual and Cu, Mn, Pb, Zn mainly exist of Fe-Mn oxides combine forms in the tailings surface and Mo is mainly bound to organic forms of existence. The conclusions are obtained through heavy metal chemical speciation of the same age in the0-20cm layer. The Mo activity of heavy metals is the most powerful in the50s and60s of last century and As activity is the lowest in artificial vegetation repaired for30years of tailings. The Cu activity is the most powerful in artificial vegetation repaired for30years,15years,5years. At last, W activity is the lowest in the1950s and1960s, artificial vegetation repaired for15years, five years and the new tailings.5. The follows are found through the mining river sediment study. Sediment organic matter first increased and then decreased, the highest content of24.31g-k·g-1. The trends between sediment heavy metals of Zn, Ni, Mn, Cr, W, Mo, Cu, Pb changes and organic matter is basically the same while the trend of As gradually reduced, which is the opposite trend of the river water and the pH value. The conclusion can be contained through the sediment organic matter, river water pH and heavy metal correlation analysis. Sediment organic matter is the influence of Zn, Ni, Mn, Cr, W, Mo, and Cu, Pb. pH value is the main factor affecting the heavy metal content of As. |
PDF Full Text Request