Environmental Pollution Assessment And Soil Microorganism Response To Environmental Factors In High Ajtitude Mining Areas In Xinjiang

Mining activities have caused serious environmental pollution and ecological damage to the mining area and its surrounding areas,but the environmental impact of mining activities in alpine areas is still poorly understood,so it is necessary to evaluate the environmental pollution and analyze the soil microorganism in mining areas.This paper takes an alpine and high altitude mining area in Xinjiang as the research object,and collects samples of soil,water and sediment in the mining area.By measuring the heavy metals and physicochemical properties of soil and analyzing the index evaluation,the heavy metal pollution status and soil quality of the mining area were evaluated.The soil bacterial community was analyzed by 16 Sr DNA sequencing method,and the distribution pattern and influencing factors of the microbial community were discussed.The results showed that:(1)The average content of heavy metals in the soil of this mining area is higher than the background value of soil in Xinjiang,and heavy metals are accumulated in the soil,mainly concentrated in the tailings.Results show that the accumulation of As,Cd and Cu is mainly from the pollutants in mining activities,the accumulation of Ni and Cr is mainly from the workers' pollution,and the accumulation of Pb and Zn is mainly from the elemental leaching of tailings and vehicle exhaust emissions.The evaluation results show that the water quality of the region is in good condition.The evaluation of potential ecological harm index and ground accumulation index of heavy metals in sediments indicated that some points from the tail mining area to mining area were moderately polluted,and the pollution degree of heavy metals in sediments was higher than that in soil.(2)The concentrations of total nitrogen(TN),total carbon(TC)and available phosphorus(AP)in mining areas are obviously lower than those in other areas.The soil was alkaline in the worker living area,neutral in the meadow-1,and acidic in the meadow-2 to the freeze-thaw area.The contents of TN,TC and total phosphorus(TP)in shady slope soil were lower than other slope sites,while the content of soil organic carbon(SOC)was higher.The biomass of the samples from the valley bottom was significantly higher than that of the samples from the sunny slope and the shady slope.The evaluation indexes that entered the minimum data set determined by principal component analysis were SOC,Cr,Ca,TC and Biomass.According to the calculation of the membership function value of the evaluation index,the soil quality index obtained is the living area > freezing-thawing area > meadow grazing area-2 >meadow grazing area-1 > tailing area >mining area,indicating that the mining area has the most serious soil pollution and the worst soil quality.(3)The abundance order of dominant bacteria in the soil of mining area was mining area >slope-2 > meadow grazing area-2 > meadow grazing area-1 > slope-3 > slope-1 > living area >freezing-thawing area > tailing area.With the increase of altitude,the relative abundance of Proteobacteria and Micrococcus verrucosa increased significantly,but the relative abundance of Actinomycetes in living areas was significantly higher than that in other areas.The abundance of these dominant flora on the slope site was higher than that on the same elevation site.According to the results of ?-diversity index analysis,SOC can promote the increase of microbial abundance and species richness.Ca,Cu,Pb,Zn and other metals accumulate in large quantities in the tailings,and are negatively correlated with the microbial community structure.Therefore,AP,p H,altitude,SOC,Zn,Ca,As and Cd are the main factors affecting the abundance of bacterial communities,and the distribution pattern of bacterial communities is driven by the combined effects of soil physical and chemical properties and toxic pollutants.