Coal Mining Caused Pollution Of Farmland Soil And Its Ecological Risk Assessment In Shenfu-dongsheng Minesite

Shenfu-Dongsheng mine area is located in the Mu Us Desert and the Loess Plateautransition zone of the northwest area of desertification, its ecological environment is fragile,accompanied by serious erosion. The mining based mainly on open-pit, which brint aboutserious damage to its original topography, vegetation landscape, restricted the sustainablesocio-economic development of the mine.In this study, two years (1990and2010) TM images of Zhungeer region were taken asthe data source, based on the landscape ecology theory and landscape pattern analysismethod. The dynamic characteristics of landscape structure, landscape patterns andlandscape vulnerability in the Zhungger mine were analyzed. Combined with theexperimental data of heavy metals in soils, we studied ecological pollution of heavy metalsin mine risk, providing a theoretical basis for the future management and protection ofecological environment of mining area, the rational allocation of the landscape pattern andsustained and effective utilization of mine resources.The results showed that:(1) During the20years, the landscape pattern of every townships in Zhungeerplaque has undergone significant changes in both landscape and patch level, among thelandscape heterogeneity deteriorated, landscape dominance reduced, and landscapediversity decreased;(2) During the20years, building land area of the three regions was increased; itsignificant affected the changes of landscape structure. The area of vegetation cover in thestudy area had an increasing trend. However, the landscape was more dispersed andirregular. The mining area exploitation was the dominate factor to effect the changes oflandscape pattern, such as enlarging the building area, destroying the farmland, andreducing the cultivated land area. Furthermore, although the woodland and grass-shrub land area were increased, its landscape pattern was more broken, and its ecosystem wasmore unstable.(3)Fragmentation (including patch density and edge density) and separation indexcombines well reflect the landscape of information and close ties between the fragilelandscape elements, in Zhungeer County area, landscape fragmentation caused by humanactivities and the degree of separation of the vulnerability landscape elements become thedecisive factor. In20years as the population, social and economic development of humanactivities on natural resources, resource development and regional high-intensity, resultingin the area of human activity on the landscape elements violent interference. During the20years, the ecological vulnerability of Zhungeer’s southern region changed biggest, whilethe ecological vulnerability of the total area was increased, indicating that its landscapeelements were lesser stable and more sensitive to outside interference.(4)Heavy metal content of four mines was quite different, while the content of SunJiahao and He Jiata colliery was significantly higher than that of Zhao Jialiang and LiuDaogou mine. Multi-affected wind and other factors, the presence of elements in eachsample point had some regularity azimuth (ES> W> N), showed significant enrichmentaccumulation trend. On the vertical profiles in the soil and lateral distance, each of heavymetals had shown a decreasing trend, with some volatility, changed in the magnitude ofdifferences.(5) Single factor pollution index and Nemerow pollution index results were basicallyconsistent, the surrounding farmland soils mines were subject to Cd, Cu, Zn, Pb polluted tovarying degrees. Where Cd pollution was the most serious, moreover71.4%and6.9%ofthe sampling points and integrated pollution reached alarming levels. The farmland heavymetals pollution of Sun Jiahao and Zhao Jialiang mine were significantly greater than thatof He Jiata and Liu Daogou mine.(6) The range of comprehensive potential ecological risk factor of soil heavy metalpollution surrounding the four mines were between14.65~241.96with an average of24.70, been at the low level of risk, but the moderate risk had reached the maximum extent.Sun Jiahao mine ecological risk was greater than the He Jiata colliery, RI values were45.03and20.04, Zhao Jialiang colliery’s ecological risk was greater than Liudaogoucolliery’s, RI values were18.74and14.97; the largest degree of ecological risk influence of individual elements was Cd element, and the minimum was Zn element, and Cd madethe biggest contribution to the RI values, was the most important mining soil environmentpollution elements and potential risks elements.Cd element is the most important miningpollution and potential risks element in the four soil environment. The soil heavy metalssurrounding the four mines were some homology with obvious characteristics of soil heavymetals contamination.