GIS (Geographic Information System)-based soil pollution prevention and control zoning method

Abstract

The invention belongs to the field of soil pollution prevention and control planning, and particularly discloses a GIS-based soil pollution prevention and control zoning method, which specifically comprises the following steps: S1, collecting basic data and data; s2, establishing a GI database; s3, dividing survey units; s4, point distribution investigation; s5, soil pollution grading; s6, pollution source load risk assessment; s7, agricultural product sample detection; s8, adjusting the partitions; s9, visualizing the map; according to the method, soil pollution categories are preliminarily divided according to soil detection conditions, then edible agricultural products of the agricultural land are sampled and detected, pollution source load risks of the construction land are evaluated and graded to serve as auxiliary judgment data to carry out secondary partitioning on the soil, the dividing accuracy is improved, and the efficiency is improved. A distribution diagram can be made for each element through the GIS software, and a plurality of diagrams are superposed and synthesized by using the GIS software, so that the soil pollution prevention and treatment classification supervision level can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of soil pollution prevention and control planning, and in particular relates to a method for delineating soil pollution prevention and control zoning based on GIS. Background Art

[0002] Soil is a complex layer of material on the surface of the earth, mainly composed of minerals, organic matter, water and air, and is the basis for plant growth; the process of soil formation is called soil formation, which is affected by many factors such as climate, topography, biology, time and parent material. Soil pollution refers to the concentration of harmful substances in the soil exceeding the natural background value or environmental standard, resulting in a decline in soil quality, disorder of ecosystem functions, and a threat to human health and biosafety. Soil pollution is regional and complex, and the characteristics and degree of soil pollution in different regions vary significantly;

[0003] Soil pollution prevention and control planning is a comprehensive and systematic plan formulated to effectively control and reduce soil pollution and protect the soil environment and human health;

[0004] However, the current soil pollution prevention and control zoning method is unable to divide the soil for construction land, and the soil quality is used alone as the demarcation standard for soil pollution prevention and control zoning, which is not accurate and inconvenient for administrative departments to manage. Summary of the invention

[0005] The purpose of the present invention is to provide a method for demarcating soil pollution prevention and control zoning based on GIS to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for delineating soil pollution prevention and control zones based on GIS, the specific steps are as follows:

[0008] S1. Basic information and data collection: Collect basic map information, natural environment resources and pollution source data of soil pollution prevention and control areas;

[0009] S2. Establish GIS database: Use GIS software to establish a spatial database and perform geocoding and attribute coding on the collected data;

[0010] S3. Divide the survey units: Divide the soil pollution prevention and control area into agricultural land and construction land according to the soil use function, and compile a soil use function zoning map under the GIS environment;

[0011] S4. Site survey: Determine the site location and density based on the area of ​​the survey unit, and conduct soil sampling and testing at the site locations;

[0012] S5. Soil pollution classification: Calculate the pollution index based on the soil test results at the distribution point, conduct evaluation and zoning, and edit and form the distribution map of various pollutants in the GIS environment;

[0013] S6. Pollution source load risk assessment: Evaluate the pollution source load in the survey unit and edit it in the GIS environment to form a soil pollution source load assessment zoning map;

[0014] S7. Agricultural product sample testing: Sampling and testing of edible agricultural products at the distribution points, and editing and forming an agricultural product sample evaluation zoning map under the GIS environment;

[0015] S8. Adjustment of zoning: Adjust the zoning categories of agricultural land according to the results of agricultural product safety assessment, and adjust the zoning categories of construction land according to the results of pollution source load risk assessment;

[0016] S9. Visual map: Create a visual map based on the results of zoning demarcation.

[0017] Preferably, the S1 step is used to obtain soil pollution standards and regulations to determine the limit values ​​of various pollutants.

[0018] Preferably, the GIS database in step S2 contains layer information on the spatial distribution, pollution sources and geographical features of different pollutants.

[0019] Preferably, in the step S4, the soil of agricultural land and construction land is divided by comparing the content of heavy metals, organic matter and inorganic matter in the detected soil with the required screening value and control value. In agricultural land, when the content of heavy metals and organic matter is less than or equal to the screening value, it indicates that the risk of soil pollution is low and can be ignored under normal circumstances, and it is classified as a priority protection class; when the content of heavy metals and organic matter is greater than the screening value but less than or equal to the control value, it indicates that there may be risks to the quality and safety of agricultural products, crop growth or soil ecological environment, and it is classified as a safe utilization class; when the content of heavy metals and organic matter is greater than the control value, it indicates that the edible land is safe. Agricultural products that do not meet quality and safety standards have a high risk of soil pollution and are difficult to reduce through safe utilization measures, and are therefore classified as strictly controlled. In construction land, when the content of heavy metals, inorganic matter and organic matter is less than or equal to the screening value, it indicates that the risk of soil pollution is low and can generally be ignored, and is therefore classified as safe utilization. When the content of heavy metals, inorganic matter and organic matter is greater than the control value, it indicates that there may be risks to human health, and is therefore classified as risk control. Risk assessments are conducted on soils where the content of heavy metals, inorganic matter and organic matter is greater than the screening value and less than the control value, and they are classified as safe utilization or risk control based on the assessment results.

[0020] Preferably, in step S5, the Kriging interpolation method is used to generalize the data of the soil monitoring points to the entire area, generate a pollution concentration distribution map, spatially superimpose the soil pollution data with other geographic information layers, and identify high-risk areas.

[0021] Preferably, the specific steps of the pollution source load risk assessment in step S6 are as follows:

[0022] S6.1: Calculate the soil pollution source load risk using the following formula:

[0023] P i =T i ×L i ×Q i ×G i ×E i

[0024] Where P i represents the pollution source load risk index of pollution source i, T i represents the toxicity of pollutants from pollution source i, L i represents the possibility of pollution release from pollution source i, Q i Indicates the amount of pollutants that may be released, G i Indicates the geological characteristics that affect soil and groundwater, E i Indicates the potential impact of construction on the environment;

[0025] S6.2: Risk levels are divided according to the calculated pollution source load risk index, and the calculated results P i The values ​​are arranged from large to small and divided into three levels: high, medium and low according to the value range. The load risk level zoning map of each type of pollution source is edited in the GIS environment;

[0026] S6.3: Comprehensively evaluate the load levels of all pollution sources, and based on the calculation results of each pollution source, superimpose them in the GIS environment to form a pollution source load level map. The calculation formula is as follows:

[0027] PI=∑W i ×P i

[0028] Where PI represents the comprehensive index of pollution source load, W i represents the weight of the i-th pollution source type, P i It represents the load of the i-th type of pollution source. The larger the PI value, the greater the load of the pollution source.

[0029] S6.4: Classify the pollution source load according to the calculated comprehensive index, arrange the calculated PI values ​​from large to small, and divide them into three levels: high, medium and low according to the value range. Edit them in the GIS environment to form a soil pollution source load assessment zoning map.

[0030] Preferably, the evaluation of pollutant toxicity in the step S6.1 needs to take into account factors such as the physicochemical properties, degradation and mobility of the pollutants, which are directly related to the carcinogenic or non-carcinogenic risk of the receptor; the possibility of release from the pollution source is closely related to its protective measures and the length of existence; the amount of pollutants that may be released is related to the scale of the pollution source and the amount of pollutant emissions. The larger the scale of the pollution source, the higher the amount of pollutant emissions.

[0031] Preferably, in step S8, the agricultural land zoning category is adjusted according to the agricultural product safety assessment results, and the soil originally classified as the priority protection category is classified into the priority protection zone 1, and the safe utilization category soils where the edible agricultural products detected at the points are not exceeded are classified into the priority protection zone 2, and the safe utilization category soils that do not meet the standards of the priority protection zone 2 are classified into the safe utilization zone 1, and the strictly controlled category soils where the number of points that do not exceed the standards accounts for ≥ 65% and there are no points with serious exceeding the standards are classified into the safe utilization zone 2, and the strictly controlled category soils that do not meet the standards of the safe utilization zone 2 are classified into the strictly controlled zone 1.

[0032] Preferably, in the step S8, the zoning category of the construction land is adjusted according to the pollution source load risk assessment result, and the safe utilization type soil with a low pollution source load level is divided into the safe utilization zone 1, the safe utilization type soil with a medium or high pollution source load level is divided into the safe utilization zone 2, the risk control type soil with a low or medium pollution source load level is divided into the strict control zone 1, and the risk control type soil with a high pollution source load level is divided into the strict control zone 2.

[0033] Preferably, in step S9, GIS software is used to perform overlay analysis on multiple maps, and different layers are synthesized to produce a visual map that delineates different soil pollution prevention and control zones.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention divides the soil pollution prevention and control area into agricultural land and construction land, distributes detection points according to the regional density, and preliminarily divides the soil pollution categories according to the soil detection results. Then, the edible agricultural products on the agricultural land are sampled and tested, and the pollution source load risk of the construction land is evaluated and graded. This is used as auxiliary judgment data to perform secondary zoning of the soil, thereby improving the accuracy of the division.

[0036] (2) The present invention can produce a distribution map for each element through GIS software, and finally use GIS software to superimpose and synthesize multiple maps to form a comprehensive visual zoning map, which can effectively improve the level of classified supervision of soil pollution prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1It is a block diagram of the specific steps of the present invention;

[0038] Figure 2 It is a flowchart of the steps of the pollution source load risk assessment of the present invention;

[0039] Figure 3 It is a load index weight block diagram of the present invention;

[0040] Figure 4 It is a block diagram of the pollution source load evaluation standard of the present invention;

[0041] Figure 5 It is a block diagram of agricultural land zoning of the present invention;

[0042] Figure 6 It is a block diagram of the construction land zoning of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] As attached Figure 1 To Attachment Figure 6 As shown:

[0045] Embodiment 1: The present invention provides a method for demarcating soil pollution prevention and control zones based on GIS, and the specific steps are as follows:

[0046] S1. Basic information and data collection: Collect basic map information, natural environment resources and pollution source data of soil pollution prevention and control areas;

[0047] S2. Establish GIS database: Use GIS software to establish a spatial database and perform geocoding and attribute coding on the collected data;

[0048] S3. Divide the survey units: Divide the soil pollution prevention and control area into agricultural land and construction land according to the soil use function, and compile a soil use function zoning map under the GIS environment;

[0049] S4. Survey site location: Determine the location and density of the survey site based on the area of ​​the survey unit, and conduct soil sampling and testing at the survey site. For agricultural land soil, focus on the testing of heavy metals such as cadmium, mercury, arsenic, lead, and chromium. For construction land, focus on the testing of volatile organic compounds, characteristic stains of soil pollutants, nitrogen and phosphorus compounds, soil pH value, pathogenic microorganisms, etc. Volatile organic compounds and pathogenic microorganisms are closely related to human health and protect the health of construction and residential populations. The detection of characteristic stains of soil pollutants helps to understand the soil quality and determine whether it is suitable for construction activities and subsequent ecological restoration measures. The concentration detection of nitrogen and phosphorus compounds can evaluate the health of soil and water quality. The detection of soil pH value helps to understand the subsequent soil improvement and plant growth plan.

[0050] S5. Soil pollution classification: Calculate the pollution index based on the soil test results at the distribution point, conduct evaluation and zoning, and edit and form the distribution map of various pollutants in the GIS environment;

[0051] S6. Pollution source load risk assessment: Evaluate the pollution source load in the survey unit and edit it in the GIS environment to form a soil pollution source load assessment zoning map;

[0052] S7. Agricultural product sample testing: Sampling and testing of edible agricultural products at the distribution points, and editing and forming an agricultural product sample evaluation zoning map under the GIS environment;

[0053] S8. Adjustment of zoning: Adjust the zoning categories of agricultural land according to the results of agricultural product safety assessment, and adjust the zoning categories of construction land according to the results of pollution source load risk assessment;

[0054] S9. Visual map: Create a visual map based on the results of zoning demarcation.

[0055] Specifically, step S1 is used to obtain soil pollution standards and regulations to determine the limit values ​​of various pollutants.

[0056] Specifically, in step S2, the GIS database contains layer information on the spatial distribution, pollution sources, and geographical features of different pollutants.

[0057] Specifically, in step S4, the soil of agricultural land and construction land is divided by comparing the contents of heavy metals, organic matter and inorganic matter in the detected soil with the required screening values ​​and control values. In agricultural land, when the contents of heavy metals and organic matter are less than or equal to the screening values, it indicates that the risk of soil pollution is low and can be ignored under normal circumstances, and it is classified as a priority protection class; when the contents of heavy metals and organic matter are greater than the screening values ​​but less than or equal to the control values, it indicates that there may be risks to the quality and safety of agricultural products, crop growth or soil ecological environment, and it is classified as a safe utilization class; when the contents of heavy metals and organic matter are greater than the control values, it indicates that edible agricultural products do not meet the quality and safety standards, the risk of soil pollution is high, and it is difficult to reduce it through safe utilization measures, and it is classified as a strict control class; in construction land, when the contents of heavy metals, inorganic matter and organic matter are less than or equal to the screening values, it indicates that the risk of soil pollution is low and can be ignored under normal circumstances, and it is classified as a safe utilization class; when the contents of heavy metals, inorganic matter and organic matter are greater than the control values, it indicates that there may be risks to human health, and it is classified as a risk control class, and the heavy metals, inorganic matter and organic matter are Risk assessment is conducted on soils with a content of substances greater than the screening value and less than the control value. According to the assessment results, they are classified as safe utilization or risk control. When the risk assessment shows that there is an unacceptable risk to human health, it should be classified as risk control, otherwise it should be classified as safe utilization. In construction land, except for the development and utilization of polluted plots, risk control measures are mainly used. For polluted plots to be planned as residential land, remediation measures are mainly used. The screening values ​​and control values ​​for agricultural land are based on the screening values ​​and control values ​​in GB15618-2018. The construction land is divided into Screening values ​​and control values ​​Based on the screening values ​​and control values ​​in GB36600-2018, the soil for construction land classified as safe utilization includes residential land, primary and secondary school land in public administration and public service land, medical and health land and social welfare facilities land, and community parks and children's parks in park green space; the soil for construction land classified as risk control includes industrial land, logistics and warehousing land, commercial service facilities land, transportation facilities land, green space and square land (excluding community parks and children's parks), etc.

[0058] Specifically, in step S5, the Kriging interpolation method is used to generalize the data of soil monitoring points to the entire area, generate a pollution concentration distribution map, spatially overlay the soil pollution data with other geographic information layers, and identify high-risk areas.

[0059] From the above, we can see that by dividing the soil pollution prevention and control area into agricultural land and construction land, the pollution prevention and control zoning standards can be dynamically adjusted according to the use functions of agricultural land and construction land. Soil sampling is carried out by means of point survey, which greatly improves the accuracy and universality of the sampling data. The soil is divided into priority protection category, safe utilization category and strict control category. GIS can be used to spatially superimpose soil pollution data with other geographic information layers, identify high-risk areas, and form zoning maps to facilitate management by administrative departments, implement zoning policies, and promote soil pollution supervision and prevention.

[0060] Embodiment 2: This embodiment is basically the same as the previous embodiment, except that the specific steps of the pollution source load risk assessment in step S6 are as follows:

[0061] S6.1: Calculate the soil pollution source load risk using the following formula:

[0062] P i =T i ×L i ×Q i ×G i ×E i

[0063] Where P i represents the pollution source load risk index of pollution source i, T i represents the toxicity of pollutants from pollution source i, L i represents the possibility of pollution release from pollution source i, Q i Indicates the amount of pollutants that may be released, G i Indicates the geological characteristics that affect soil and groundwater, E i Indicates the potential impact of construction on the environment;

[0064] S6.2: Risk levels are divided according to the calculated pollution source load risk index, and the calculated results P i The values ​​are arranged from large to small and divided into three levels: high, medium and low according to the value range. The load risk level zoning map of each type of pollution source is edited in the GIS environment;

[0065] S6.3: Comprehensively evaluate the load levels of all pollution sources, and based on the calculation results of each pollution source, superimpose them in the GIS environment to form a pollution source load level map. The calculation formula is as follows:

[0066] PI=∑W i ×P i

[0067] Where PI represents the comprehensive index of pollution source load, W i represents the weight of the i-th pollution source type, P iIt represents the load of the i-th type of pollution source. The larger the PI value, the greater the load of the pollution source.

[0068] S6.4: Classify the pollution source load according to the calculated comprehensive index, arrange the calculated PI values ​​from large to small, and divide them into three levels: high, medium and low according to the value range. Edit them in the GIS environment to form a soil pollution source load assessment zoning map.

[0069] Specifically, the evaluation of pollutant toxicity in step S6.1 needs to take into account factors such as the physicochemical properties, degradation and mobility of pollutants, which are directly related to the carcinogenic or non-carcinogenic risk of the receptor; the possibility of release from the pollution source is closely related to its protective measures and the length of existence; the amount of pollutants that may be released is related to the scale of the pollution source and the amount of pollutant emissions. The larger the scale of the pollution source, the higher the pollutant emissions.

[0070] From the above, we can see that the load risk index of a single pollution source is calculated by taking into account the toxicity of pollutants, the possibility of pollution release from pollution sources, the amount of pollutants that may be released, the geological characteristics affecting soil and groundwater, and the potential impact of construction on the environment. Then, the pollution source load neutralization index is iteratively calculated and graded to provide data assistance for each soil pollution prevention and control zone, thereby making the soil pollution prevention and control zoning of construction land more accurate.

[0071] Embodiment 3: This embodiment is basically the same as the previous embodiment, except that in step S8, the zoning category of agricultural land is adjusted according to the results of the agricultural product safety evaluation, and the soil originally classified as the priority protection category is classified into the priority protection zone 1, and the safe utilization category soil in which the edible agricultural product detection points are not exceeded is classified into the priority protection zone 2, and the safe utilization category soil that does not meet the standards of the priority protection zone 2 is classified into the safe utilization zone 1, and the strictly controlled category soil with the number of points that do not exceed the standard accounting for ≥ 65% and no points with severe exceeding the standard is classified into the safe utilization zone 2, and the strictly controlled category soil that does not meet the standards of the safe utilization zone 2 is classified into the strict control zone 1. Severe exceeding the standard means that the heavy metal content exceeds 2 times the national standard limit value.

[0072] Specifically, in step S8, the zoning category of construction land is adjusted according to the pollution source load risk assessment result, and the safe utilization type soil with a low pollution source load level is divided into the safe utilization zone 1, the safe utilization type soil with a medium or high pollution source load level is divided into the safe utilization zone 2, the risk control type soil with a low or medium pollution source load level is divided into the strict control zone 1, and the risk control type soil with a high pollution source load level is divided into the strict control zone 2.

[0073] Specifically, in step S9, GIS software is used to overlay and analyze multiple maps, synthesize different layers, and produce a visual map that delineates different soil pollution prevention and control zones.

[0074] From the above, we can see that the safety assessment results of edible agricultural products are used to adjust the soil environmental quality category of agricultural land, and then divide its soil pollution prevention and control zones. The pollution source load risk assessment results are used to adjust the soil environmental quality category of construction land, and then divide its soil pollution prevention and control zones. This makes the zoning more accurate, and each element is expressed through each GIS map. Finally, GIS software is used to superimpose and synthesize multiple maps to form a comprehensive visual zoning map, which can effectively improve the level of classified supervision of soil pollution prevention and control.

[0075] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for delineating soil pollution prevention and control zones based on GIS, characterized in that: The specific steps are as follows: S1. Basic information and data collection: Collect basic map information, natural environment resources and pollution source data of soil pollution prevention and control areas; S2. Establish GIS database: Use GIS software to establish a spatial database and perform geocoding and attribute coding on the collected data; S3. Divide the survey units: Divide the soil pollution prevention and control area into agricultural land and construction land according to the soil use function, and compile a soil use function zoning map under the GIS environment; S4. Site survey: Determine the site location and density based on the area of ​​the survey unit, and conduct soil sampling and testing at the site locations; S5. Soil pollution classification: Calculate the pollution index based on the soil test results at the distribution point, conduct evaluation and zoning, and edit and form the distribution map of various pollutants in the GIS environment; S6. Pollution source load risk assessment: Evaluate the pollution source load in the survey unit and edit it in the GIS environment to form a soil pollution source load assessment zoning map; S7. Agricultural product sample testing: Sampling and testing of edible agricultural products at the distribution points, and editing and forming an agricultural product sample evaluation zoning map under the GIS environment; S8. Adjustment of zoning: Adjust the zoning categories of agricultural land according to the results of agricultural product safety assessment, and adjust the zoning categories of construction land according to the results of pollution source load risk assessment; S9. Visual map: Create a visual map based on the results of zoning demarcation.

2. The method for demarcating soil pollution prevention and control zones based on GIS according to claim 1, characterized in that: The S1 step is used to obtain soil pollution standards and regulations to determine the limit values ​​of various pollutants.

3. The method for delineating soil pollution prevention and control zones based on GIS according to claim 2 is characterized by: In the step S2, the GIS database contains layer information of spatial distribution, pollution sources and geographical features of different pollutants.

4. The method for delineating soil pollution prevention and control zones based on GIS according to claim 3 is characterized by: In the step S4, the soil of agricultural land and construction land is divided by comparing the content of heavy metals, organic matter and inorganic matter in the detected soil with the required screening value and control value. In agricultural land, when the content of heavy metals and organic matter is less than or equal to the screening value, it means that the risk of soil pollution is low and can be ignored under normal circumstances, and it is classified as a priority protection class; when the content of heavy metals and organic matter is greater than the screening value but less than or equal to the control value, it means that there may be risks to the quality and safety of agricultural products, crop growth or soil ecological environment, and it is classified as a safe utilization class; when the content of heavy metals and organic matter is greater than the control value, it means that edible agricultural products may be contaminated. The products do not meet the quality and safety standards, the risk of soil pollution is high, and it is difficult to reduce it through safe utilization measures, so they are classified as strictly controlled. In construction land, when the content of heavy metals, inorganic and organic matter is less than or equal to the screening value, it means that the risk of soil pollution is low and can generally be ignored. It is classified as safe utilization. When the content of heavy metals, inorganic and organic matter is greater than the control value, it means that there may be risks to human health. It is classified as risk control. Risk assessment is conducted on soils where the content of heavy metals, inorganic and organic matter is greater than the screening value and less than the control value, and they are classified as safe utilization or risk control according to the assessment results.

5. The method for delineating soil pollution prevention and control zones based on GIS according to claim 4 is characterized in that: In the step S5, the Kriging interpolation method is used to generalize the data of the soil monitoring points to the entire area, generate a pollution concentration distribution map, spatially superimpose the soil pollution data with other geographic information layers, and identify high-risk areas.

6. The method for delineating soil pollution prevention and control zones based on GIS according to claim 5, characterized in that: The specific steps of the pollution source load risk assessment in step S6 are as follows: S6.1: Calculate the soil pollution source load risk using the following formula: P i =T i ×L i ×Q i ×G i ×E i Where P i represents the pollution source load risk index of pollution source i, T i represents the toxicity of pollutants from pollution source i, L i represents the possibility of pollution release from pollution source i, Q i Indicates the amount of pollutants that may be released, G i Indicates the geological characteristics that affect soil and groundwater, E i Indicates the potential impact of construction on the environment; S6.2: Risk levels are divided according to the calculated pollution source load risk index, and the calculated results P i The values ​​are arranged from large to small and divided into three levels: high, medium and low according to the value range. The load risk level zoning map of each type of pollution source is edited in the GIS environment; S6.3: Comprehensively evaluate the load levels of all pollution sources, and based on the calculation results of each pollution source, superimpose them in the GIS environment to form a pollution source load level map. The calculation formula is as follows: PI=∑W i ×P i Where PI represents the comprehensive index of pollution source load, W i represents the weight of the i-th pollution source type, P i It represents the load of the i-th type of pollution source. The larger the PI value, the greater the load of the pollution source. S6.4: Classify the pollution source load according to the calculated comprehensive index, arrange the calculated PI values ​​from large to small, and divide them into three levels: high, medium and low according to the value range. Edit them in the GIS environment to form a soil pollution source load assessment zoning map.

7. The method for delineating soil pollution prevention and control zones based on GIS according to claim 6, characterized in that: The evaluation of pollutant toxicity in the S6.1 step needs to take into account factors such as the physicochemical properties, degradation and mobility of the pollutants, which are directly related to the carcinogenic or non-carcinogenic risk of the receptors; the possibility of release from the pollution source is closely related to its protective measures and the length of time of existence; the amount of pollutants that may be released is related to the scale of the pollution source and the amount of pollutant emissions. The larger the scale of the pollution source, the higher the pollutant emissions.

8. The method for delineating soil pollution prevention and control zones based on GIS according to claim 7, characterized in that: In the step S8, the agricultural land zoning category is adjusted according to the agricultural product safety assessment results, and the soil originally classified as the priority protection category is classified into the priority protection zone 1, and the safe utilization category soils that do not exceed the standards of edible agricultural products at the points are classified into the priority protection zone 2, and the safe utilization category soils that do not meet the standards of the priority protection zone 2 are classified into the safe utilization zone 1, and the strictly controlled soils with the number of points that do not exceed the standards accounting for ≥ 65% and no points that seriously exceed the standards are classified into the safe utilization zone 2, and the strictly controlled soils that do not meet the standards of the safe utilization zone 2 are classified into the strictly controlled zone 1.

9. The method for delineating soil pollution prevention and control zones based on GIS according to claim 8, characterized in that: In the step S8, the zoning category of the construction land is adjusted according to the pollution source load risk assessment result, and the safe utilization type soil with a low pollution source load level is divided into the safe utilization zone 1, the safe utilization type soil with a medium or high pollution source load level is divided into the safe utilization zone 2, the risk control type soil with a low or medium pollution source load level is divided into the strict control zone 1, and the risk control type soil with a high pollution source load level is divided into the strict control zone 2.

10. The method for delineating soil pollution prevention and control zones based on GIS according to claim 9, characterized in that: In the step S9, GIS software is used to perform overlay analysis on multiple maps, synthesize different layers, and produce a visual map that delineates different soil pollution prevention and control zones.

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