Comprehensive Evaluation And Risk Identification Of Soil Heavy Metals In Tea Production Areas Of Plateau Mountainous

Soil is the foundation of agricultural production.As the source of quality and safety of agricultural products,the quality and safety of soil have become the most basic guarantee and lifeline of sustainable development of modern agriculture.What we had done to ensure the food safety for the masses were carrying out a comprehensive analysis of multi-source data integration,expanding the application of multi-source information collection and fusion evaluation.The results can support the fine analysis and real-time visualization of the quality and safety status of agricultural products,increase the analysis resolution of pollution source,improve the trend analysis quality and early-warning ability of soil environmental quality and provide data support for soil environmental protection decision-making,management and law enforcement.It is of great theoretical and practical significance to evaluate the risk situation of heavy metals in agricultural areas.Taking tea production areas in plateau mountainous as study area,integrating various methods of soil heavy metal evaluation,the risk zones identification model of soil heavy metals was built with the technical support of GIS spatial analysis and visual geo-modeling to evaluate the content and environmental risks of soil heavy metals of tea production areas in plateau mountainous.Through data analysis and evaluation results visualization,the pollution status and spatial distribution characteristics of soil heavy metals in tea production areas were systematically analyzed,and the risk zones of soil heavy metals in tea producing areas were preliminarily identified and classified.(1)Compared with the evaluation results of national standard and local soil background values,single pollution index and Nemerow multi-factor index indicated that the soil heavy metals pollution in the study area was mainly affected by the pollution of exogenous heavy metals,and the soil heavy metals pollution was low in the background of national standard,concentrated at clean and still clean grades.Compared with national standard,the pollution area of each soil heavy metal elements increased significantly at mild pollution level and moderate pollution level in the local background values.(2)Based on the view of geological background and ecological environment safety,the degree of pollution accumulation in the study area was pollution-free or sporadic mild pollution.The contribution of comprehensive ecological risk was low,which indicated that the soil quality of tea production was better.From the potential ecological risk index of a single heavy metal element,there was no significant difference of the spatial distribution.Only Cd elements have multiple levels of contamination at the risk level.The main reason is the northern part of the study area is the urban human activity intensive area.(3)The model of soil environmental quality evaluation of the tea production in the plateau mountainous is constructed by visual programming language,and the "one-button" automatic geography process is used to quickly complete the heavy metal data Processing and analysis,the model is applicable to the evaluation of soil environmental quality of tea origin.(4)The comprehensive index for identification of heavy metals in soils of tea producing areas was established.The tea producing area soil quality safety risk identification model was set up by using the superposition evaluation method of factor analysis,and GIS statistical analysis module.Then plateau mountain tea producing area soil heavy metals pollution risk zones was divided into.The high risk zone(?)is distributed in the north and central part of the study area.The main influencing factors are in the geological fracture zone and the impact of human activities.The middle risk zone(?)is located in the southwest of the study area,(I)are mainly distributed in the northeastern part of the northeastern part of the study area,the eastern and northeastern stratigraphic fault zone and the south.The influencing factors are complicated and the tourism industry is affected by the tourism industry,mineral development,road traffic and others.