| With the development of economy and society, the exploitation of mineralresources in China gradually increase and the Zinc Mine environmental pollutionproblems is increasingly serious.The pollution sources in Lead-zinc is Mine tailingsand wastes generated in smelting process, which is mainly four heavy metals,such asleads,zinc,copper,cadmium elements.These metals is not only caused by thedegradation of soil quality, and endanger human health through the food chain.The paper based on soil heavy metal elements pollution problems in Changhualead-zinc mine wasteland of Hainan,and selects soil heavy metal pollution of minewasteland and ecological restoration as the goal. The paper study4kinds of heavymetal elements, such Pb、 Zn、 Cu、 Cd,and study contents of heavy metalelements,effective contents of heavy metal elements, heavy metal elementsdistribution and enrichment characteristics of dominant plants and phytoremediationprospects. The main conclusions can be summed up as follows:1. The average value of Pb、 Zn、 Cu、 Cd of study area were6503.21mg/kg,3960.59mg/kg,351.49mg/kg,40.34mg/kg respectively.Each study area hashigher levels of heavy metals concentrations in soils,which is mainly affected by theimpact of abandoned lead-zinc mine tailings, and smelting. The average value ofPb,Zn,Cu,Cd in topsoil of study area were4787.4mg/kg,2915.2mg/kg,248.97mg/kg,24.84mg/kg respectively.The highest value is in the tailing area and the lowestvalue is in the reclamation area. The horizontal distribution of topsoil heavy metalelements is that the highest value is in the tailing area. The value of the reclamationarea is higher than the periphery area.The average value of the study area as follows:Pb the tailing area> the periphery area> the reclamation area、Zn the reclamationarea> the tailing area> the periphery area、Cu the tailing area> the periphery area>the reclamation area、Cd the reclamation area> the tailing area> the periphery area.2. The average value of Pb、Zn、Cu、Cd in effective content were1023.29mg/kg，164.22mg/kg,42.75mg/kg,5.89mg/kg.The average percentage of effective state is 13.08%,8.05%,18.21%,49.29%.The average value of Pb,Zn,Cu and Cd in topsoileffective content were630.31mg/kg,173.00mg/kg,37.17mg/kg,6.47mg/kg.The contentof Pb and Cu in the tailing area were the highest and the content of Zn and Cd in thereclamation area were the highest and the content of Zn、Cu、Cd in the periphery areawere the highest.The average value of Pb、Zn、Cu、Cd in topsoil is as follows: Pb thetailing area> the periphery area> the reclamation area、Zn the reclamation area> thetailing area> the periphery area、Cu the tailing area> the reclamation area> theperiphery area、Cd the reclamation area> the tailing area> the periphery area.3..Correlation analysis:total Cd and Zn was a significant negative correlation;Cuand Pb was a significant negative correlation..it explains that these elements have thesame source,and the geochemical properties is similar. Cd and Zn was a significantnegative correlation in the effective content of topsoil;Cu and Pb was a significantnegative correlation in the effective content of topsoil. Total Cd and the effectivecontent Cd was no correlation.4.The thesis has adopted Accumulation index method to evaluate the topsoilheavy metal pollution in researching area.The results shows that the gradings of Igeoof Pb reach to6, Zn reach to5,Cu reach to6,and Cd reach to6，which indicate thatthe soil pollution of Cu, Cd, Pb and Zn is most serious.5.There are6dominant plants.Heavy metals are mainly accumulated in rootsand the underground part were low levels. All plants have not reached thehyperaccumulator critical content. The enrichment capacity of Casuarina ishighest,which is Greater than1. The six species with higher transfer coefficient isCasuarina and lobular Eucalyptus. Therefore, select the Casuarina and lobulareucalyptus as the ecological restoration vegetation of abandoned land. |
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