Studies Of The Dimensional Distribution Of Soil Heavy Metal Pollution And Its Risk Assessment

Heavy metal contamination of land and water resource is a serious problem affecting the environment and human health in many countries of the world. During the process of the exploitation of heavy metals mines in China, both vegetation, landscape, land and water are all destroyed in varying degrees due to long-term neglection of ecological environmental protection and restoration. Heavy metal pollution result in soil quality degeneration which seriously threats human health and the natural ecological system. In this article, the ecological restoration technology of heavy metal mines area was reviewed. Three major repair measures involving geological engineering, vegetation restoration and soil remediation were covered. Furthermore, the technical process scheme for the heavy metal pollution of mining ecological restoration is established, which is used to provide reference for mine ecological environment management including the investigation of pollution situation, the application of remediation techniques, and subsequent maintenance and development in the early stages of repair, preliminary stage as well as the later stage.Twenty four samples from 12 farmland and woodland sites(around the mine area) were collected to measure the concentrations of nine trace elements. The results showed that the concentration of the most metals in both woodland and farmland study areas exceeded the reference soils of Zhejiang Province. The correlation, cluster and multiple principal component analysis revealed the enrichment of the metals like Pb、Cd、Zn、Cu due to mixed inputs from agrochemical, the tailing heaps and the mining transportation into farmland. Heavy metal contamination was evaluated through risk assessment(Nemero synthesis index). Concerning farmland soils, four areas could be marked as the severe pollution status, 50% of the study area fell in Low pollution; while one area belonged to the grade two risk. Moreover, 75% of the woodland study areas were Severe in pollution. The results highlight the environmental impact assessment of mining and will provide a basis for assessment of the environmental costs of cleaning up the ecosystems adjoining the mine sites.The soil samples(97) were collected from the study area to assess the status of metal pollution in soils adjacent to bamboo plantations around the mining area of southeast China. The median soil Cd, Cr, Cu, Mn, Pb and Zn concentrations were 0.50 mg·kg-1, 58.31 mg·kg-1, 27.89 mg·kg-1, 405.89 mg·kg-1,286.32 mg·kg-1, 209.53 mg·kg-1.The risk assessment confirmed that about 60.82% of the study area suffered from metal contamination. The pollution evaluation map provides a reference for the food security and the classification management of bamboo forest. Various metal pollutants transported from some source may considerably affect the properties of transported soils. The descriptive statistics showed that most of soil heavy metal concentrations(Pb, Zn, Cu and Cd) exceeded the background value of Zhejiang Province and most of the heavy metal content in area B(plain) was higher than that of area A(valley). The results of global Moran I statistics illustrated that the high-high clusters in soils for all the heavy metals were strongly influenced by mineral transport in area A.LISA maps showed that all heavy metals did not have similar spatial autocorrelation in area B. The spatial distribution maps showed that most of the metals like Zn, Cu, Cd and Pb have the same effective ranges in the fields of area A along the road, indicating that they may have the similar spatial structure and variation caused by some extrinsic factors.For Quzhou City above the town more macroscopic investigation of soil heavy metal pollution, found that heavy metal enrichment is not only related to mining activities, and over the entire town landscape pattern has relevance, among them, the landscape diversity affect the irregularity of the spatial distribution of heavy metal accumulation, the higher the degree of landscape fragmentation of the soil heavy metal pollution in the possibility of higher, reunion type development pattern of landscape diversity in space distribution, landscape factors can also affect the spatial distribution of soil heavy metal content.