Comprehensive evaluation method and system for remediation effect of heavy metal contaminated soil

Abstract

The invention provides a comprehensive evaluation method and system for the remediation effect of heavy metal contaminated soil, and relates to the technical field of environmental engineering.The method specifically comprises the steps that remote sensing data of a contaminated area is obtained, a soil sample is collected, the microbial respiration rate and the soil physicochemical property of the soil sample are measured, the remote sensing data are processed, and a normalized vegetation index is obtained; generating a soil health assessment index based on the collected physical and chemical properties of the soil; integrating the soil evaluation index, the microbial respiration rate and the normalized vegetation index to construct a soil remediation evaluation index; and comparing the remediation evaluation index with a preset evaluation threshold value, and evaluating the remediation effect of the heavy metal contaminated soil. According to the method, the soil health evaluation index and the remediation evaluation index are constructed, so that the evaluation accuracy of the remediation effect of the heavy metal contaminated soil is effectively improved. Through multivariate correlation analysis, biological, chemical and physical characteristics of the soil can be comprehensively reflected, and a scientific basis is provided for subsequent management and remediation measures.

Description

Technical Field

[0001] The present invention relates to the field of environmental engineering technology, and in particular to a comprehensive evaluation method and system for the restoration effect of heavy metal contaminated soil. Background Art

[0002] Heavy metal pollution is a widespread environmental problem worldwide, especially in areas of rapid industrialization, where the concentration of heavy metals in the soil often exceeds environmental safety standards. These heavy metals, such as lead, cadmium, and mercury, not only harm plant growth, but also pose a threat to animal and human health through the food chain. Although a variety of remediation technologies, such as physical, chemical, and biological methods, have been widely used, existing technologies have obvious deficiencies in evaluating remediation effects. Many traditional methods mainly rely on changes in heavy metal concentrations as evaluation indicators, and do not fully consider the biological activity and ecological functions of the soil. Traditional detection methods often lack dynamic monitoring capabilities and are difficult to reflect the remediation status of the soil in real time. In addition, a single heavy metal concentration indicator cannot comprehensively evaluate soil health, which often leads to underestimation or misjudgment of the remediation effect.

[0003] On the other hand, existing assessment methods generally ignore the importance of microbial activity and vegetation status in soil remediation. Microorganisms not only play a key role in the transformation and removal of heavy metals, but their biological respiration rate can also serve as an important indicator of soil health. At the same time, although the application of remote sensing technology has gradually become popular, it is still insufficient in the comprehensive assessment of heavy metal contaminated soils. Remote sensing data are usually used to monitor the distribution status of soil and vegetation, but lack in-depth analysis of changes in soil physical and chemical properties. This makes it challenging for management decision makers to formulate soil remediation plans and unable to accurately grasp the soil's recovery capacity and potential risks. Therefore, there is an urgent need for a more systematic and comprehensive assessment method to comprehensively reflect the remediation effect of heavy metal contaminated soils and guide effective governance measures.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a comprehensive evaluation method and system for the remediation effect of heavy metal contaminated soil 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 comprehensive evaluation method for the remediation effect of heavy metal contaminated soil, the specific steps include:

[0008] Step 1: Obtain remote sensing data of the polluted area and collect soil samples, measure the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the Normalized Difference Vegetation Index (NVDI). The soil physical and chemical properties are soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration. Step 2: Based on the dimensionless soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration, perform correlation analysis to generate a soil health assessment index.

[0009] Step 3: Perform multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct soil restoration assessment index;

[0010] Step 4: Compare the remediation assessment index with the preset assessment threshold. Based on the comparison results, evaluate the remediation effect of heavy metal contaminated soil and propose corresponding management and remediation measures.

[0011] Furthermore, the specific logic for collecting the microbial respiration rate is as follows: collect a first soil sample of a certain mass from the contaminated area to be evaluated, place the first soil sample in a respiration chamber, seal it and maintain a constant temperature of 25°C, use a gas analyzer to regularly measure the CO2 concentration change in the respiration chamber, record the time and CO2 concentration of each measurement, and calculate the microbial respiration rate according to the following formula:

[0012]

[0013] Where RS is the microbial respiration rate, ΔC is the change in CO2 concentration in the respiration chamber, ΔP is the time during the measurement, V is the volume of the respiration chamber, and m is the mass of the first soil sample;

[0014] The specific logic of collecting remote sensing data is as follows: according to the soil remediation plot to be evaluated, the regional boundaries are drawn to ensure that all areas that need to be monitored are covered, and the monitoring area is photographed by a drone to collect remote sensing data. During the flight, the sensor captures images of different bands at regular intervals, and the images taken by the drone are spliced ​​using image processing software to generate a complete orthophoto. The images of the red light and near-infrared bands are extracted from the generated orthophoto, and the NVDI is calculated according to the following formula:

[0015]

[0016] Among them, NVDI is the normalized vegetation index, NIR is the near-infrared band reflectance, and RED is the red light band reflectance.

[0017] Furthermore, the specific logic for collecting soil pH value is as follows: compare the collected soil pH value with the preset pH assessment threshold value; if it exceeds the threshold range, calculate the difference between the current soil pH value and the preset threshold value, which is recorded as ΔP; if it does not exceed the threshold range, it will not be included in the subsequent calculation of the soil health assessment index;

[0018] The specific logic of collecting soil moisture content is as follows: collect a certain mass of soil samples from the contaminated area to be evaluated, use the drying method to heat the soil samples to a certain temperature in a constant temperature oven until they reach a constant weight NCkg, and calculate the moisture loss to determine the moisture content:

[0019]

[0020] Among them, MC is the moisture content of the soil, GC is the initial weight of the soil sample, and NC is the dry weight of the soil sample; the current soil moisture content is compared with the preset moisture content threshold. If it exceeds the threshold range, the difference between the current soil moisture content and the preset threshold is calculated and recorded as ΔMC; if it does not exceed the threshold range, it will not be included in the subsequent calculation of the soil health assessment index;

[0021] The specific logic of collecting soil organic matter content is as follows: collect a second soil sample of a certain mass from the contaminated area to be evaluated, air-dry the second soil sample, remove large particles and impurities, and determine the organic matter content therein by potassium dichromate oxidation method; mix the second soil sample with a potassium dichromate solution of a certain concentration, add sulfuric acid for oxidation, determine the amount of potassium dichromate that does not participate in the reaction after the reaction, and calculate the organic matter content, which is recorded as OM:

[0022]

[0023] Wherein, OM is the organic matter content, V1 is the required initial volume of potassium dichromate solution, V2 is the volume of potassium dichromate solution that does not participate in the reaction, N is the concentration of potassium dichromate solution, n is the mass of the second soil sample, and 0.004 is a constant used for conversion, which represents the corresponding oxidation amount of organic matter;

[0024] The specific logic of collecting soil heavy metal concentration is as follows: collect a certain mass of soil samples from the contaminated area to be evaluated, air-dry the soil samples, remove large particles and impurities, grind the soil samples into uniform powder, and digest the soil samples with a mixture of concentrated nitric acid and hydrochloric acid according to standard methods to convert them into soluble forms, and use atomic absorption spectrometry to determine the heavy metal concentration. The heavy metals are specifically: Pb, Cd, Hg, Cu, and the comprehensive concentration of soil heavy metals is calculated according to the following formula:

[0025]

[0026] Among them, COM is the comprehensive concentration of heavy metals in the soil, and C i is the concentration of the i-th heavy metal, i is the index of the heavy metal, and i ∈ [1, 4].

[0027] Furthermore, the formula for generating the soil health assessment index is as follows:

[0028]

[0029] Among them, SOIL is the soil health assessment index, OM is the organic matter content, ΔP is the difference between the soil pH value and the preset threshold, ΔMC is the difference between the soil moisture content and the preset threshold, COM is the comprehensive concentration of heavy metals in the soil, and C1 is the first constant correction index;

[0030] Furthermore, the formula for constructing the soil repair assessment index is as follows:

[0031] QS = α * SOIL + β * RS + γ * NVDI + C2

[0032] Among them, QS is the repair assessment index, SOIL is the soil health assessment index, α is its preset proportionality coefficient, RS is the microbial respiration rate, β is its preset proportionality coefficient, NVDI is the normalized difference vegetation index, γ is its preset proportionality coefficient, and α > β > γ > 0, C2 is the second constant correction index.

[0033] Furthermore, the specific logic for comparing the repair assessment index with the preset assessment threshold is as follows:

[0034] When QS ≤ 0.5QY, it is judged that the repair effect is not good and there are still heavy metal pollution problems in the soil; if the soil health assessment index and microbial activity meet the standards, then moderate fertilization and increasing organic materials are adopted to continue to improve the soil; if the NDVI value is lower than the preset threshold NY, then heavy metal-tolerant plants are introduced for ecological restoration;

[0035] When 0.5QY < QS ≤ QY, it is judged that the soil health is in a marginal state and further observation and management are required;

[0036] When QS > QY, it is judged that the repair effect is significant, the soil quality has been improved, and no further repair is required;

[0037] Among them, QS is the repair assessment index, and QY is the preset assessment threshold.

[0038] The present invention also further provides a comprehensive evaluation system for the repair effect of heavy metal-polluted soil. The comprehensive evaluation system for the repair effect of heavy metal-polluted soil is used to execute the above-mentioned comprehensive evaluation method for the repair effect of heavy metal-polluted soil, including:

[0039] A data acquisition module is used to obtain remote sensing data of the polluted area and collect soil samples, measure the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the Normalized Difference Vegetation Index (NVDI). The soil physical and chemical properties include soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration;

[0040] The data processing module performs correlation analysis based on dimensionless soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration to generate a soil health assessment index.

[0041] The index construction module is used to conduct multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct a soil restoration assessment index;

[0042] The comprehensive evaluation module is used to compare the remediation evaluation index with the preset evaluation threshold, evaluate the remediation effect of heavy metal contaminated soil based on the comparison results, and propose corresponding management and remediation measures.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention effectively improves the accuracy of the assessment of the remediation effect of heavy metal contaminated soil by constructing a soil health assessment index and a remediation assessment index. Through multivariate correlation analysis, the biological, chemical and physical properties of the soil can be comprehensively reflected, providing a scientific basis for subsequent management and remediation measures. The establishment of this comprehensive assessment system not only helps to identify the key influencing factors in the soil remediation process, but also provides more reliable data support for policy makers, thereby promoting the sustainable development of soil ecosystems. Through this method, the optimization of soil remediation strategies can be more effectively guided, and the efficiency and effectiveness of environmental governance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0046] Figure 2 It is a schematic diagram of the overall system module of the present invention. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0048] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] Example:

[0050] See also Figure 1 , the present invention provides a technical solution:

[0051] A comprehensive evaluation method for the remediation effect of heavy metal contaminated soil, the specific steps include:

[0052] Step 1: Obtain remote sensing data of the polluted area and collect soil samples, determine the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the normalized vegetation index (NVDI), wherein the soil physical and chemical properties are soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration; In this embodiment, the specific logic for collecting the microbial respiration rate is as follows: collect a first soil sample of a certain mass from the polluted area to be evaluated, place the first soil sample in a respiration chamber, seal it and maintain a constant temperature of 25°C, use a gas analyzer to regularly measure the CO2 concentration change in the respiration chamber, record the time and CO2 concentration of each measurement, and calculate the microbial respiration rate according to the following formula:

[0053]

[0054] Where RS is the microbial respiration rate, ΔC is the change in CO2 concentration in the respiration chamber, Δt is the time during the measurement, V is the volume of the respiration chamber, and m is the mass of the first soil sample;

[0055] The specific logic of collecting remote sensing data is as follows: according to the soil remediation plot to be evaluated, the regional boundaries are drawn to ensure that all areas that need to be monitored are covered, and the monitoring area is photographed by a drone to collect remote sensing data. During the flight, the sensor captures images of different bands at regular intervals, and the images taken by the drone are spliced ​​using image processing software to generate a complete orthophoto. The images of the red light and near-infrared bands are extracted from the generated orthophoto, and the NVDI is calculated according to the following formula:

[0056]

[0057] Among them, NVDI is the normalized vegetation index, NIR is the near-infrared band reflectance, and RED is the red light band reflectance.

[0058] The specific logic of collecting soil pH value is as follows: comparing the collected soil pH value with the preset pH assessment threshold value, if it exceeds the threshold range, calculating the difference between the current soil pH value and the preset threshold value, recorded as ΔP; if it does not exceed the threshold range, it will not be included in the subsequent calculation of the soil health assessment index;

[0059] The specific logic of collecting soil moisture content is as follows: collect a certain mass of soil samples from the contaminated area to be evaluated, use the drying method to heat the soil samples to a certain temperature in a constant temperature oven until they reach a constant weight NCkg, and calculate the moisture loss to determine the moisture content:

[0060]

[0061] Among them, MC is the moisture content of the soil, GC is the initial weight of the soil sample, and NC is the dry weight of the soil sample; the current soil moisture content is compared with the preset moisture content threshold. If it exceeds the threshold range, the difference between the current soil moisture content and the preset threshold is calculated and recorded as ΔMC; if it does not exceed the threshold range, it will not be included in the subsequent calculation of the soil health assessment index;

[0062] The specific logic of collecting soil organic matter content is as follows: collect a second soil sample of a certain mass from the contaminated area to be evaluated, air-dry the second soil sample, remove large particles and impurities, and determine the organic matter content therein by potassium dichromate oxidation method; mix the second soil sample with a potassium dichromate solution of a certain concentration, add sulfuric acid for oxidation, determine the amount of potassium dichromate that does not participate in the reaction after the reaction, and calculate the organic matter content, which is recorded as OM:

[0063]

[0064] Wherein, OM is the organic matter content, V1 is the required initial volume of potassium dichromate solution, V2 is the volume of potassium dichromate solution that does not participate in the reaction, N is the concentration of potassium dichromate solution, n is the mass of the second soil sample, and 0.004 is a constant used for conversion, which represents the corresponding oxidation amount of organic matter;

[0065] The specific logic of collecting soil heavy metal concentration is as follows: collect a certain mass of soil samples from the contaminated area to be evaluated, air-dry the soil samples, remove large particles and impurities, grind the soil samples into uniform powder, and digest the soil samples with a mixture of concentrated nitric acid and hydrochloric acid according to standard methods to convert them into soluble forms, and use atomic absorption spectrometry to determine the heavy metal concentration. The heavy metals are specifically: Pb, Cd, Hg, Cu, and the comprehensive concentration of soil heavy metals is calculated according to the following formula:

[0066]

[0067] Among them, COM is the comprehensive concentration of heavy metals in soil, C i is the concentration of the i-th heavy metal, i is the index of the heavy metal, and i∈[1,4].

[0068] The advantage of step 1 is that by comprehensively collecting soil samples and conducting multi-dimensional measurements, it can more accurately reflect the health status and pollution level of the soil. This comprehensive data collection not only covers microbial activities, remote sensing information and soil physical and chemical properties, but also provides multi-level and multi-angle information support for subsequent evaluations through the acquisition of NDVI, thereby ensuring the accuracy and reliability of the evaluation results. Compared with the existing technology, the beneficial effect of step 1 is reflected in its systematicity and comprehensiveness. Traditional technology often focuses on the analysis of a single indicator or a local area, while this step can more comprehensively evaluate the overall health level and heavy metal pollution of the soil by integrating multiple key parameters. This multi-dimensional evaluation method can effectively make up for the shortcomings of the existing technology in terms of data one-sidedness and evaluation accuracy. In this patent scheme, the use of step 1 can lay a solid data foundation for the overall evaluation scheme. Through comprehensive sample collection and multi-dimensional analysis, the subsequent steps can more accurately reflect the soil remediation effect and improve the reliability of the remediation evaluation index.

[0069] Step 2: Based on the dimensionless soil pH value, soil moisture content, soil organic matter content and soil heavy metal concentration, correlation analysis is performed to generate a soil health assessment index;

[0070] In this embodiment, the formula for generating the soil health assessment index is as follows:

[0071]

[0072] Among them, SOIL is the soil health assessment index, OM is the organic matter content, ΔP is the difference between the soil pH value and the preset threshold, ΔMC is the difference between the soil moisture content and the preset threshold, COM is the comprehensive concentration of soil heavy metals, and C1 is the first constant correction index. Organic matter is an important indicator of soil health. Organic matter can promote soil microbial activity and improve soil structure. Therefore, when OM increases, the soil health assessment index SOIL increases accordingly; soil pH affects nutrient availability and the living environment of microorganisms; if the soil pH is within the preset threshold range, it usually means that the soil conditions are suitable for plant growth and microbial activity, thereby improving the soil health assessment index; if the pH is too low or too high, it may lead to nutrient imbalance, affect plant growth, and thus reduce the soil health assessment index; soil moisture content directly affects plant growth and microbial activity. If the moisture exceeds the threshold, it may cause plants to be overwatered or drought-stricken, thereby reducing the soil health assessment index; heavy metal concentration is a key indicator for assessing the degree of soil pollution. If the heavy metal concentration is higher than the threshold, it indicates that the soil is polluted, reducing the soil health assessment index; that is, OM is positively correlated with SOIL, and ΔP, ΔMC, and COM are negatively correlated with SOIL.

[0073] Step 3: Perform multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct soil restoration assessment index;

[0074] In this embodiment, the soil restoration assessment index is constructed based on the following formula:

[0075] QS=α*SOIL+β*RS+γ*NVDI+C2

[0076] Among them, QS is the restoration evaluation index, SOIL is the soil health evaluation index, α is its preset proportionality coefficient, RS is the microbial respiration rate, β is its preset proportionality coefficient, NDVI is the normalized difference vegetation index, γ is its preset proportionality coefficient, and α > β > γ > 0. This is because the soil health evaluation index, as a comprehensive index, combines multiple soil characteristics and thus has a higher weight when evaluating the overall health status of the soil. NDVI is mainly used to evaluate the vegetation growth status and coverage, indirectly reflecting soil health. C2 is the second constant correction index. NDVI is an important indicator reflecting the vegetation growth status and health degree. A higher NDVI value usually indicates good vegetation growth and strong biological activity, while a lower NDVI may indicate damaged vegetation, which may be related to heavy metal pollution. Therefore, when NDVI increases, the restoration evaluation index QS increases. A higher soil health evaluation index means a good soil environment that can support diverse biological communities and microbial activities. Therefore, when SOIL increases, the restoration evaluation index QS increases. The microbial respiration rate is an important indicator of soil microbial activity, reflecting the decomposition of organic matter and nutrient cycling in the soil. A higher microbial respiration rate usually indicates strong soil microbial activity, effective decomposition of organic matter and nutrient release, thereby promoting plant growth. A low plant respiration rate may imply poor soil fertility or pollution, thus reducing the soil health evaluation index. Therefore, when RS increases, the restoration evaluation index QS increases. That is to say, SOIL, RS, NDVI and QS are positively correlated.

[0077] Step 4: Compare the restoration evaluation index with a preset evaluation threshold. Based on the comparison result, evaluate the restoration effect of the heavy metal contaminated soil and propose corresponding management and restoration measures.

[0078] In this embodiment, the specific logic followed in the process of comparing the restoration evaluation index with the preset evaluation threshold is as follows:

[0079] When QS ≤ 0.5QY, it is judged that the restoration effect is not good and there are still heavy metal pollution problems in the soil. If the soil health evaluation index and microbial activity reach the standards, adopt the method of moderate fertilization and increasing organic materials to continue to improve the soil. If the NDVI value is lower than the preset threshold NY, introduce heavy metal tolerant plants for ecological restoration.

[0080] When 0.5QY < QS ≤ QY, it is judged that the soil health is in a marginal state and further observation and management are required.

[0081] When QS > QY, it is judged that the restoration effect is significant, the soil quality has been improved, and no further restoration is required.

[0082] Among them, QS is the restoration evaluation index and QY is the preset evaluation threshold.

[0083] The advantage of step 4 is that by comparing the remediation evaluation index with the preset evaluation threshold, the remediation effect of heavy metal contaminated soil can be effectively evaluated. This comparison can not only intuitively reflect the effectiveness of the remediation measures, but also provide a scientific basis for subsequent management and decision-making. This systematic evaluation method ensures the transparency and traceability of the remediation process, allowing managers to adjust the remediation strategy in a timely manner; compared with the prior art, the beneficial effect of step 4 is that its comparative analysis based on the comprehensive evaluation index makes the evaluation more systematic and quantitative. Traditional methods often rely on empirical judgments or single indicators, while this step can evaluate the soil remediation effect from a quantitative perspective by introducing a preset threshold, significantly improving the objectivity and reliability of the results, thereby enhancing the scientific nature of the decision. In this patent scheme, the use of step 4 can provide an effective feedback mechanism for the overall evaluation scheme. Through real-time monitoring and evaluation of the remediation evaluation index, problems in the remediation process can be identified in a timely manner to ensure the effectiveness of management measures.

[0084] See also Figure 2 The present invention also provides a comprehensive evaluation system for the remediation effect of heavy metal contaminated soil, comprising:

[0085] A data acquisition module is used to obtain remote sensing data of the polluted area and collect soil samples, measure the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the Normalized Difference Vegetation Index (NVDI). The soil physical and chemical properties include soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration;

[0086] The data processing module performs correlation analysis based on dimensionless soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration to generate a soil health assessment index.

[0087] The index construction module is used to conduct multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct a soil restoration assessment index;

[0088] The comprehensive evaluation module is used to compare the remediation evaluation index with the preset evaluation threshold, evaluate the remediation effect of heavy metal contaminated soil based on the comparison results, and propose corresponding management and remediation measures.

[0089] The specific values ​​of α, β and γ in the formula are generally determined by technical personnel in this field according to actual conditions. The technical personnel in this field collect multiple groups of sample data, and set corresponding preset proportional coefficients for each group of sample data. The preset proportional coefficients and the collected sample data are substituted into the formula. Through repeated experiments and parameter adjustments, the accuracy of the model output and the rationality of the results are observed, and these factor coefficients are gradually adjusted. The performance and effect of the model under different parameter settings are compared to find the optimal coefficient combination, and the calculated factor coefficients are screened and averaged to obtain the values ​​of α, β and γ.

[0090] In addition, the size of the preset factor coefficient is to quantify each parameter to obtain a specific value. In order to facilitate subsequent comparison, the size of the coefficient depends on the amount of sample data and the preset proportional coefficient initially set by technical personnel in this field for each set of sample data. It is not unique as long as it does not affect the proportional relationship between the parameter and the quantized value.

[0091] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0092] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0093] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0094] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A comprehensive evaluation method for the remediation effect of heavy metal contaminated soil, characterized in that: The specific steps include: Step 1: Obtain remote sensing data of the polluted area and collect soil samples, measure the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the Normalized Difference Vegetation Index (NVDI). The soil physical and chemical properties include soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration; Step 2: Based on the dimensionless soil pH value, soil moisture content, soil organic matter content and soil heavy metal concentration, correlation analysis is performed to generate a soil health assessment index; Step 3: Perform multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct soil restoration assessment index; Step 4: Compare the remediation assessment index with the preset assessment threshold. Based on the comparison results, evaluate the remediation effect of heavy metal contaminated soil and propose corresponding management and remediation measures.

2. The comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to claim 1 is characterized in that: The specific logic of collecting the microbial respiration rate is as follows: collect a first soil sample of a certain mass from the contaminated area to be evaluated, put the first soil sample into a respiration chamber, seal it and keep it at a constant temperature of 25°C, use a gas analyzer to regularly measure the CO2 concentration change in the respiration chamber, record the time and CO2 concentration of each measurement, and calculate the microbial respiration rate according to the following formula: Where RS is the microbial respiration rate, ΔC is the change in CO2 concentration in the respiration chamber, Δt is the time during the measurement, V is the volume of the respiration chamber, and m is the mass of the first soil sample; The specific logic of collecting remote sensing data is as follows: according to the soil remediation plot to be evaluated, the regional boundaries are drawn to ensure that all areas that need to be monitored are covered, and the monitoring area is photographed by a drone to collect remote sensing data. During the flight, the sensor captures images of different bands at regular intervals, and the images taken by the drone are spliced ​​using image processing software to generate a complete orthophoto. The images of the red light and near-infrared bands are extracted from the generated orthophoto, and the NVDI is calculated according to the following formula: Among them, NVDI is the normalized vegetation index, NIR is the near-infrared band reflectance, and RED is the red light band reflectance.

3. The comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to claim 1 is characterized in that: The specific logic of collecting soil pH value is as follows: comparing the collected soil pH value with the preset pH assessment threshold value, if it exceeds the threshold range, calculating the difference between the current soil pH value and the preset threshold value, recorded as ΔP; if it does not exceed the threshold range, it will not be included in the subsequent calculation of the soil health assessment index; The specific logic of collecting soil moisture content is as follows: collect a certain mass of soil samples from the contaminated area to be evaluated, use the drying method to heat the soil samples to a certain temperature in a constant temperature oven until they reach a constant weight NCkg, and calculate the moisture loss to determine the moisture content: Wherein, MC is the moisture content of the soil, GC is the initial weight of the soil sample, and NC is the dry weight of the soil sample; compare the moisture content of the current soil with the preset moisture content threshold. If it exceeds the threshold range, calculate the difference between the moisture content of the current soil and the preset threshold, denoted as ΔMC; if it does not exceed the threshold range, it will not be included in the calculation when calculating the soil health assessment index subsequently. The specific logic for collecting the soil organic matter content is as follows: collect a certain mass of the second soil sample from the pollution area to be evaluated, air-dry the second soil sample, remove large particles and impurities, and use the potassium dichromate oxidation method to determine the organic matter content therein. After mixing the second soil sample with a potassium dichromate solution of a certain concentration, add sulfuric acid for oxidation, measure the amount of potassium dichromate that did not participate in the reaction after the reaction, and calculate the organic matter content, denoted as OM. Wherein, OM is the organic matter content, V1 is the initial volume of the potassium dichromate solution required, V2 is the volume of the potassium dichromate solution that did not participate in the reaction, N is the concentration of the potassium dichromate solution, n is the mass of the second soil sample, and 0.004 is a constant used for conversion, representing the oxidation amount of the corresponding organic matter. The specific logic for collecting the soil heavy metal concentration is as follows: collect a certain mass of the soil sample from the pollution area to be evaluated, air-dry the soil sample, remove large particles and impurities, grind the soil sample into a uniform powder, acid-digest the soil sample with a mixture of concentrated nitric acid and hydrochloric acid according to the standard method to convert it into a soluble form, and use atomic absorption spectrometry to measure the heavy metal concentration. The heavy metals are specifically: Pb, Cd, Hg, Cu. Calculate the comprehensive soil heavy metal concentration according to the following formula: Among them, COM is the comprehensive concentration of heavy metals in soil, C i is the concentration of the i-th heavy metal, i is the index of the heavy metal, and i∈[1,4].

4. The comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to claim 1 is characterized in that: The formula for generating the soil health assessment index is as follows: Wherein, SOIL is the soil health assessment index, OM is the organic matter content, ΔP is the difference between the soil pH value and the preset threshold, ΔMC is the difference between the soil moisture content and the preset threshold, COM is the comprehensive soil heavy metal concentration, and C1 is the first constant correction index.

5. The comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to claim 1 is characterized in that: The formula for constructing the soil repair assessment index is as follows: QS = α * SOIL + β * RS + γ * NVDI + C2 Wherein, QS is the repair assessment index, SOIL is the soil health assessment index, α is its preset proportionality coefficient, RS is the microbial respiration rate, β is its preset proportionality coefficient, NVDI is the normalized difference vegetation index, γ is its preset proportionality coefficient, and α > β > γ > 0, C2 is the second constant correction index.

6. The comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to claim 5 is characterized by: The specific logic for comparing the repair assessment index with the preset assessment threshold is as follows: When QS ≤ 0.5QY, it is judged that the repair effect is not good and there are still heavy metal pollution problems in the soil; if the soil health assessment index and microbial activity meet the standards, moderate fertilization and increasing organic materials are adopted to continue to improve the soil; if the NDVI value is lower than the preset threshold NY, heavy metal-tolerant plants are introduced for ecological restoration. When 0.5QY < QS ≤ QY, it is judged that the soil health is in a marginal state and further observation and management are required. When QS>QY, it is judged that the restoration effect is significant, the soil quality has been improved, and no further restoration is needed; Among them, QS is the restoration evaluation index, and QY is the preset evaluation threshold.

7. A comprehensive evaluation system for the remediation effect of heavy metal contaminated soil, characterized by: A comprehensive evaluation system for the remediation effect of heavy metal contaminated soil, characterized in that: the comprehensive evaluation system for the remediation effect of heavy metal contaminated soil is used to execute the comprehensive evaluation method for the remediation effect of heavy metal contaminated soil according to any one of claims 1 to 6, comprising: A data acquisition module is used to obtain remote sensing data of the polluted area and collect soil samples, measure the microbial respiration rate and soil physical and chemical properties, and process the remote sensing data to obtain the Normalized Difference Vegetation Index (NVDI). The soil physical and chemical properties include soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration; The data processing module performs correlation analysis based on dimensionless soil pH, soil moisture content, soil organic matter content, and soil heavy metal concentration to generate a soil health assessment index. The index construction module is used to conduct multivariate correlation analysis on soil assessment index, microbial respiration rate and normalized vegetation index to construct a soil restoration assessment index; The comprehensive evaluation module is used to compare the remediation evaluation index with the preset evaluation threshold, evaluate the remediation effect of heavy metal contaminated soil based on the comparison results, and propose corresponding management and remediation measures.

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