Research And Implementation Of Ecological Risk Assessment Model ERA

The effective content of heavy metals in soil has an important indicator effect on ecological and environmental risks.Due to weather,geographical environment,etc.,it is difficult to sample on-site,and the ecological risk assessment of the study area cannot be performed in time.In response to this problem,the Daxia River Basin in northwest China is used as the research area.Based on the remote sensing information Vegetation Index(NDVI)and the monitoring values of environmental meteorological factors,a remote heavy metal ecological risk assessment model(ERA)for the river basin was constructed.Based on the established ecological risk assessment model,an ecological risk assessment system was developed and designed to realize remote assessment of the ecological risk situation in the study area.The main research work is as follows:(1)Use SPSS to choose the factors that influence the ecological risk assessment of the study area.The main influencing factors are the altitude,water flow,PH value,precipitation and temperature of the study area.The results show that the heavy metal content in the study area is mainly affected by precipitation,temperature and NDVI value.There is a multivariate linear relationship between average heavy metal content and precipitation,temperature and NDVI.The correlation(correlation coefficient)is r = 0.866,and the significance level is less than 0.01.The results show that the precipitation,temperature and NDVI values can be used to characterize the heavy metal content in the soil in the study area.(2)By studying the ecological risk assessment method,combining the specific watershed conditions of the study area,and integrating various data indicators,the Hakanson potential risk index method was finally selected as the basic evaluation method for establishing the ERA model.(Including fuzzy mathematics and gray clustering in the model index method,the index methods include single factor index,Nemero comprehensive pollution index,geological accumulation index,Hakanson potential risk index method,and other methods based on GIS-based geostatistical assessment methods and Health risk assessment method).The analysis of the average heavy metal content and ecological risk index shows that there is a nonlinear relationship between them,the correlation(correlation coefficient)is r = 0.893,and the significance level is less than 0.01 in the same time period in the study area.That is,the ecological risk level of the study area can be determined through this relationship.(3)The established ecological risk assessment model(ERA)is applied to different types of watershed land types such as grassland,forest land,cultivated land,towns,and waters.In order to explore the ecological risk levels of different land use types in the same area of the study area,as well as the ecological risk conditions of different land use types in different areas.The results of the study further indicate that the risk assessment of the watershed can be used through remote sensing information and environmental factors.It also reveals that expanding the woodland area helps to suppress the increase in the risk level of the ecological environment.At the same time,for better management and control,the research area is divided into small areas with administrative regions as the unit.The use of ERA model evaluation shows that the upstream risk status of the research area is better than that of the downstream.The risk status is higher than the ecological risk level in areas with little human activity.(4)Based on the established ecological risk assessment model(ERA),through the use of WebGIS technology and ArcGIS development platform,combined with the Microsoft Visual Studio 2013 development platform,the construction and development of the ecological risk assessment system can realize the management of remote ecological risk assessment in the research area.The application results show that this system enables the assessment of ecological risk levels in the study area and the classification of pollution levels.At the same time,the analysis of heavy metal content and meteorological factors was also completed in the Daxia River Basin.It enables remote assessment of ecological risk assessment problems in the study area,and can be visually displayed intuitively.At the same time,it can carry out ecological risk assessment more efficiently and in real time.