Research On Soil Heavy Metal Pollution And Phytoremediation In Ni-Cu Mining Area Of Jinchuan

The development activity of nonferrous metals mine caused serious soil heavymetal pollution to mine areas and the surrounding areas, which became the mainsource of environmental pollution of mine areas. It is very difficult for this kind ofpollution to be restored. However, the phytoremediation technology of low price, lessenvironmental disturbance and no secondary pollution is the most effective measurefor the soil heavy metal pollution control in metal mine areas and the improvement ofeco-environmental quality. Therefore, this dissertation takes Gansu province Jinchangcity Jinchuan nickel copper mine as research areas to carry out field vegetation surveyand collect plant samples as well as rhizosphere soil samples. The analysis of mea-suring the heavy metal content of plants and soil as well as physical and chemicalproperties of soil and the evluation towards soil nutrient status in mine areas and thepollution condition caused by heavy metals have been carried out to make clear thepollution degree of heavy metal in mine areas and determine soil improvement meas-ures; The field investigation towards plants and the measuring on the enrichment andmetastasis potential towards heavy metal caused by dominant plants have been carriedout in order to screen out the heavy metal resistant plants suitable for the soil condi-tion in this research area or the plants with (potential)hyper-accumulator characteris-tics. Then the perfect pattern of forest vegetation will be selected and the late main-tenance management will be strengthened to complete phyto-remediation project. Theresearch results show that:(1)The soil heavy metal pollution in the study area is serious. So, it was task forthe abandoned mines pollution control and ecological restoration.The main pollution factor of Longshou mountain mining area is Ni, Cd, Cu, Co,Zn. The two kinds mainly of heavy metals were Ni and Cu, at the same time asso-ciated with compound pollution of Cd, Co, Zn and other heavy metals. Thus greatlyaccentuates the remediation of heavy metal contaminated soil treatment and reclama-tion work difficulty. Therefore, should attract the attention of the relevant departmentsfor heavy metals in soils in the region of the repair work. In order to avoid the heavy metal ions in soil by plant uptake through the food chain bioaccumulation to harmhuman and livestock health. The region is not suitable for planting crops and foragetemporarily. Priority should be given to the development of forestry. In order to solvethe soil improvement, we could plant the botany which could absorb heavy metals.Then, considering the development of animal husbandry industry or planting.（2）The compound pollutiont of the heavy metal Mn、Ni、Cu、Cd、Zn、As is in the nonferrous metals mineland.And there may be homoeologous relationshipbetween these heavy metal elements.The correlation between the content of heavy metals in soil shows that, As andNi, Pb and Zn was significantly related to. Cu also significantly correlated with otherheavy metals, but no significant correlation with As, Cr. Co and Cu, Ni and significantcorrelation between Pb, Zn, and a weak correlation. Pb, Zn and Cd three kinds ofheavy metals showed significant correlation. Significant correlation exists betweenthe various elements of heavy metal, suggests that there may be homologous rela-tionship between them, and the mining activities.(3) The content of exchangeable Ni、Cu in Gansu province Jinchang city Jin-chuan nickel copper mine is the highest All those factors have the highest effective-ness and toxity on plants.Adopting Tessier sequential extraction to perform sample analysis: the content ofexchangeable Ni、Cu in surrounding mountain area around stopes is the highest. Allthose factors have the highest effectiveness and toxity on plants.(4) The enrichment and metastatic potential of analysis as well as comparisontowards heavy metal have been carried out about main dominat plants in the nonferr-ous metals mineland. And the plants of caragana, tamarisk, ceratoides, atraphax-is bracteata and atriplex canescens have stronger cumulate ability for heavy metal sothat a theoretic basic can be provided for the selection of pioneer plants in the vegeta-tion restoration process.Field survey has been conducted the natural plant community on the abandonedland in mine areas and analysis as well as determination have been carried out aboutmain dominat plants and relative analysis has been performed about their heavy metal content in the rhizosphere soil: The advantage of the aerial parts of the plant Ni con-tent, significantly positive correlation with the content of the soil; Cu content of theunderground parts, there were significant negative correlation with the content of thesoil; there was no obvious correlation between the Mn and Zn.(5) Sifting heavy metal resistant plants or the plants with (potential) hy-per-accumulator characteristics such as tamarix ramosissima and Caragana intermediaintermedia. And the optimus plant disposition mode are determined and applied in thevegetation restoration project through planting trials.According to community succession theory, the vegetation restoration process ofabandoned land in mine areas begins with the introduction of pioneer plants andreaches the mesophytic climax community in the end after a series of successionstages. Sift the heavy metal resistant plants or the plants with (potential) hy-per-accumulator characteristics: selecting the plant variety possessing strong resis-tence against heavy metal like tamarix ramosissima and Caragana intermedia inter-media as well as sea buckhorn etc in Longshoushan mine area as the poineer speciesof plant restoration on the abandoned land in research areas. Comparison for the abil-ity of transferring heavy metals by plants.