The Research On Ananlysis And Assessment For Soil Environmental Monitoring Information Based On GIS

At present,the soil environmental condition in our country is not optimistical as a whole.For example,in some areas soil is seriously polluted,arable soil quality is worrying,and soil environmental problems of industrial and mineral wasteland are outstanding day by day.Aiming at the increasingly serious soil pollution,environmental monitoring is gradually strengthen.But due to a lack of systematic and scientific basic research,there is no a set of scientific and effective analysis and assessment system for soil environmental monitoring information.The article took heavy metal pollution that is the most prominent problem in soil pollution as key point,and Zhongxiang phosphorus mining area that is one of key polluted areas in Hubei Province as the study area,and focused on five aspects,including spatial variability and source analysis,quantitative analysis of landscape factors,time prediction and pollution assessment,layout optimization of monitoring point and construction of information platform,to carry out the analysis and assessment of soil environmental monitoring information.The main contents were as follows:1)Research process of spatial variability,hotspots identification,and source analysis for soil heavy metals at single scale and multi-scale was set up by geostatistics,spatial autocorrelation,and statistics methods.The results indicated that at single scale and short scale,heavy metals showed obvious spatial heterogeneity,some hotspots were caused by human activities,and remaining hotspots were related to natural factors.At long scale,spatial variability of heavy metals was controlled by parent materials.2)The multi-scale relationship between soil heavy metals and landscape factors was studied and the contribution of landscape factors to heavy metal accumulation was quantified by correlation analysis,geographically weighted regression(GWR)analysis,and partial redundancy analysis.The results showed that most heavy metals were significantly correlated with parent materials and landscape pattern indexes at all scales.At optimal scale,the relationship between heavy metals and landscape factors showed obvious spatial heterogeneity,and significant relevant areas were situated at advantage areas of corresponding landscape factors.The contribution of three groups of landscape factors(including parent materials,distance variables,and landscape pattern indexes)to heavy metal variation depended on analysis scale,and in general,the contribution decreased in the following order:parent materials>landscape pattern indexes>distance variables.3)Prediction model of soil heavy metals was built by situational approach,and pollution and risk condition of heavy metals was assessed by single factor index,Nemerow index,potential ecological risk index and fuzzy evaluation method.The results showed that at optimistic scenario in 2020 contents of all heavy metal decreased to some extent,and contents of some heavy metals decreased significantly.At no mutation scenario in 2020 contents of all heavy metals increased significantly.Heavy metals showed a certain degree of ecological risk of pollution,and the areas that had high ecological risk were greatly influenced by human activities.4)Reasonable sample number of monitoring and layout optimization schemes at different constraint conditions were studied by classical statistics and spatial simulated annealing algorithm.The results showed that the reasonable sample number was related to confidence level,precision,and variation degree.If there is no a priori knowledge,layout optimization can be carried out by the criterion of Minimizations of the Mean of Shortest Distances(MMSD).If there is a priori knowledge,layout optimization can be achieved by the criterion of Minimization of the Mean of Kriging Estimation Variance(MMKEV).If there is a priori knowledge and sample uniform distribution is demanded,layout optimization can be carried out by combining MMSD and MMKEV criterion.5)Analysis and assessment system for soil environmental monitoring was designed and developed using Visual Studio and ArcGIS Engine,and provides function of storage,management,query,prediction,evaluation and analysis for soil environmental monitoring data.It has the characteristics of openness,stable operation,and easily use,and can basically meet the needs of analysis and evaluation of soil environmental monitoring information,but still need to be improved and perfected.