| As a compound ecosystem affected by the development and utilization of coal resources,the opencast coal mining area and its surroundings become areas where the contradiction between the ecological environment and the socio-economy is very apparent.The coalfield of the East Junggar Basin is rich in coal resources.Meanwhile,it is located in a typical arid and deserted area,with an extremely fragile ecological environment.The timely monitoring and evaluation of changes in surface disturbances,environmental pollution,and local socio-economic development in the coal mining areas and around the East Junggar Basin coalfield is an effective approach to maintain the coordinated development of the ecological environment and socio-economy in the region.The present research was targeted on the typical region in the coalfield of the East Junggar Basin.The changes of land use,the distribution,enrichment and transport characteristics of the polluted heavy metals,the spatial/temporal patterns of atmospheric particulate pollutions,and the environmental and socio-economic development features around the East Junggar Basin mining areawere examined.The relationship between land use/cover types and environmental pollution were analyzed using the geographically weighted regression（GWR）model.The relationship between land use types and socio-economic development was examined by the sustainable development model.The eco-compensation and proposals on the ecological and environmental conservationregarding the East Junggar Basin coalfield were estimated by the restore and losses cost methods.The main conclusions are as follows.1)Between 2006 and 2014,the land use types in the western and eastern mining areas were dominated by bare land,sandy land and vegetation.The area of the bare land,the mining area,the dumping area,the construction land,and the water area increased year by year.The vegetation area increased,followed by a decrease.From 2006 to 2010,The change degree of the the mining area in the two mining regions were higher than 90%,and the comprehensive land use dynamic degree was 46.762 and 53.871 respectively.From 2010 to2014,the change amplitude of dumpwas higher than 50%and intensity higher than 1%.The comprehensive land use dynamic degree was 38.136 and 43.930 respectively.In 2010,the land use information entropy and the land use degree comprehensive index of the two mining areas were the highest.Between 2010 and 2014,the sandy land increased whereas the bare land maintained stable in the western mining area.The vegetation area mainly reduced,in contrast,the mining area,dump and construction land mainly increased in this area.However,to the eastern mining area,the spatial changes of sand and bare ground in the were mainly unchanged.The vegetation areas were mainly unchanged or decreased,while the mining area,dump and construction land mainly increased.2)The contents of Zn,Cu,and Pb did not exceed the standard background values of soil in Xinjiang.However,the contents of Cr,Hg,and As were 60%higher than the standard background values.The values of PLI,HI and TCR in 0-10 cm soil layer were higher than other two soil layers,indicating a slightly pollution,and no significant difference were found in the PLI,HI,TCR.To the 0-10 cm soil layer,Zn,Cu,and As were significantly enriched around the coal industrial area and northern part of studying region.Pb showd a V-shaped high content ribbon.Hg was highly enriched in the central and southern part.The Cr content decreased radially from the industrial area to the peripheral areas.The areas of high PLI、HI and TCR value were located in northwest and northeast of the research region.The moderate pollution region of PLI decreased with the increase of soil depth.The HI and TCR showed no significant changes.The contribution rates of the first principal components of the three soil layers were 37.896%,37.985%,and 33.872%,respectively.Cu and Zn enriched in the surrounding soils due to effects of the leading wind and atmospheric sedimentation.The contribution rates of the second principal components were 25.574%、25.350%,and 24.093%,respectively.Cr and Hg might be originated from contaminants produced during production and transportation.The contribution rates of the third principal component were 16.712%,15.551%and 16.157%,respectively.Pb might be derived from the soil parent material.The contribution of As（010cm）was much higher in the third principal component,probably same as the source of Cu and Zn.3)The average PM10 and PM2.5 during four months in study area did not exceed the daily average concentration limits of ambient air quality standard（GB3095-2012）.The values of PM100 and PM2.5 were in the order of December>July>May>September.The spatial distribution pattern of PM100 and PM2.5 was nearly identical in the same month,and the high concentration region were basically distributed around the industrial area.The PM10 and PM2.5 were positively related with the humidity.The temperature was negatively related with the PM10.The wind speed was negatively correlated with PM10 and PM2.5 in September and December,but was opposite in May and July.The humidity was the primary factor affecting the dust concentration and distribution.The heavy metals were important components of PM2.5 and PM10,but the effects of different heavy metals depended on seasonal climate conditions.Pb had the most negative correlation with humidity in July.Rainfall had a certain flushing effect on Pb.In December,there was a positive correlation between Zn,Cu,AS,Cr and PM2.5,PM10,and wind speed,indicating that the concentration of atmospheric particulates was high and the heavy metal pollution more serious in winter.4)Plants（Anabasis salsa,Ephedra distachya,Haloxylon ammodendron,and Reaumuria songonica）surrounding the coal mines had strong ability to enrich Zn,Cu and Cr,but weak for As.The enrichment coefficient to the heavy metals was less than 1 in most plants,indicating that they were low heavy metals accumulation plants.The transport capacity of different plants in different sites varied greatly,but all higher than 1.Plants had the ability to absorb heavy metals and transport them to the aerial parts.The transport ability of plants near the coal mine became weak,showing that it might be a self-protection strategy for plants against heavy metals.There was a significant positive correlation between Pb and soil organic matter.Cr was significantly negatively correlated with organic matter.The correlations between Zn,Cu,Hg,and As and organic matter was weak.Therefore,organic matter was not a major factor affecting the distribution of heavy metals in the soil of the studying area.5)From 2006 to 2014,the economic power of the Jimsar county and Qitai county increased significantly.All economic indicators showed an overall growth trend.The industrial structure altered apparently,in that the proportion of the first and third industries declined,while the secondary industry increased significantly.The industrial added value risen rapidly,and people’s living standards improved.The disposable income of agricultural and pastoral households and the number of employed people increased rapidly since 2010.The number of population slightly increased.The GDP of Qitai county was higher than the Jimsar county.The highest values of the comprehensive development index of the Jimsar County and Qitai County were 0.7414 in 2013 and 0.8306 in 2014,respectively.The allometric growth factors of the total population and socio-economic indicators in the Jimsar County and Qitai County are 0.9813 and 1.0267,respectively,and no positive allometric growth existed.The total population of the two counties and 10 indicators showed a isometric growth pattern,reflecting the population growth rate was harmonious with the socio-economic indicators.6)The negative correlation between the vegetation area and the heavy metal content GWR of most areas in the western Junggar Basin coalfield.The vegetation areas presented a positive correlation to negative correlation with As content in the central part of the research area,but showed a alternative of positively and negatively correlation with Cr content.The vegetation area ratio was positively correlated with PM10 content in the eastern part of the studying area,while negatively correlated in the western part of the sandy land and the surrounding area of the industrial and mining area.The land use composite index was the lowest in 2010 and the socio-economic composite index was the lowest in 2006.The type of coordinated development was"reluctant to coordinate land use lag"of the study area in 2006,2010 and 2014.The bare land,mining area,dump,construction land,and water areas were the main factors causing land use changes in the western mining area of coalfield in the East Junggar Basin.7)In 2014,the total cost of ecological compensation for the East Junggar Basin coal was1178.7603 million yuan.The vegetation restoration cost was the highest,accounting for34.94%.The water pollution treatment cost accounted for 30.57%.The air and solid waste loss cost accounted for 19.14%.The land reclamation cost cost was 10.08%.The coal gangue pollution loss cost,ecological service value cost and ecology and environmental maintenance accounts for less than 1%of the total cost.The estimated ecological compensation of the East Junggar Basin was less than 1/10 of the income of coal sales which fallen within the standard scope.It is suggested that the ecological environment protection should be improved in aspects of the coalfield environmental management system,boosting the environmental protection consciousness of coal mining enterprise,prevention and management of ecological environment destruction,and diversifying the ecological compensation funds. |
