Analysis method and system for soil Cd / Pb complex contamination bimetallic isotope source

Abstract

The present invention discloses a method for analyzing the Cd / Pb complex bimetallic isotope source of agricultural soil contamination. The method includes the steps of using a sampling device to separately collect soil samples and risk source samples, respectively measuring the Cd and Pb isotope ratios of the soil samples and risk source samples, plotting the Cd and Pb isotope ratios of the soil samples and risk source samples as coordinates to obtain an isotope ratio projection diagram, identifying the polluting end-members that pollute agricultural soil using the isotope ratio projection diagram, obtaining the identification results of the polluting end-members, further confirming the polluting end-members, calculating the relative contribution rate of the polluting end-members, and obtaining the isotope source analysis results. The present invention utilizes the mutual constraint and mutual verification of two kinds of Cd-Pb metal isotopes to solve the problems of similar or overlapping sample isotope values ​​and the decrease in analysis accuracy caused by isotope fractionation, and realizes accurate identification and quantitative analysis of the Cd / Pb heavy metal pollution source of agricultural soil.

Description

[Technical field]

[0001] The present invention relates to the research field of soil heavy metal pollution prevention and control, and more particularly to a method and system for analyzing soil Cd / Pb complex contamination bimetallic isotope source. [Background technology]

[0002] Heavy metals Cd and Pb are globally recognized toxic metal elements. Cd and Pb in soil have characteristics such as relatively poor mobility, high toxicity, difficult decomposition, and bio-amplification through food chains and food webs, which pose a great threat to human health. Therefore, soil Cd / Pb complex contamination has certain peculiarities and is a difficulty in soil heavy metal contamination management, and at the same time, it is a hot spot and difficult research topic that has attracted attention at home and abroad. As the degree of agricultural soil Cd / Pb contamination becomes increasingly serious, simply studying the form, type and spatial distribution of soil heavy metal pollutants cannot meet the existing agricultural soil management needs. However, because the agricultural soil medium environment is very complex, it is difficult to accurately identify the pollution source and difficult to quantify the pollution contribution, so it is difficult to target and manage agricultural soil heavy metal pollution, and the management effect is insufficient. Therefore, it is very urgent and necessary in the soil Cd / Pb contamination management action to develop a method that can effectively determine the Cd / Pb pollution source in agricultural soil and quantify the contribution rate of each pollution source.

[0003] At present, most of the contamination source analysis work of Cd and Pb in soil usually relies on large databases and mathematical statistical analysis. For example, there are factor analysis, principal component analysis, clustering analysis, rich factor method, etc., but these methods can only qualitatively analyze the source type of heavy metals in soil. In addition, methods such as chemical mass balance and positive definite matrix factorization can realize source analysis at the qualitative and quantitative level, but they are based on large-scale and comprehensive sampling and cumbersome mathematical analysis, which is labor-intensive and difficult to distinguish multi-element systems.

[0004] In recent years, with the development of chemical analysis technology, the application of metal isotope fingerprint feature traceability has brought a new idea to soil heavy metal source analysis methods. In nature, each substance has its own "label" composed of isotopes, so the source of a mixture can be distinguished through the specific "label" of the isotope composition of each substance. Cd is 106 Cd, 108 Cd, 110 Cd, 111 Cd, 112 Cd, 113 Cd, 114 Cd and 116 Cd has eight isotopes, and Pb is found in nature. 204 Pb, 206 Pb, 207 Pb and 208 It has four isotopes of Pb, where: 204 Pb is the only primordial stable isotope formed during the great explosion. 206 Pb, 207 Pb and 208 Pb is 238 U, 235 U and 232 Cd is a radioactive decay product of Th. Currently, there are a few reports of single metal isotope soil contamination traceability using one of the Cd or Pb isotopes. Usually, the ratio of metal concentration or its reciprocal to the metal stable isotope is used to analyze the contamination source. Cloquet et al. collected contamination sources such as soil around a smelter, dust particles, and residual slag in a boiler, measured Cd isotopes, and tentatively determined the contamination source by plotting the reciprocal of Cd isotope value vs. Cd concentration. Linear analysis revealed that dust particles and waste slag were the main sources of Cd contamination in the soil in this area. Liu et al. analyzed the soil Pb source in a soil-rice system using field monitoring, Pb isotope ratio analysis, etc., and the results showed that the Pb sources in the paddy soil were background soil, fertilizer, atmospheric deposition, and irrigation water.

[0005] However, geochemical processes in soil, such as adsorption, dissolution, redox reactions, and biological processes, can fractionate Cd isotopes, blurring the Cd isotope signals of the contamination source and reducing the accuracy of Cd single isotope source analysis results. Summary of the Invention [Problem to be solved by the invention]

[0006] The primary objective of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a method and system for analyzing soil Cd / Pb mixed contaminated bimetallic isotope sources.

[0007] A first object of the present invention is to provide a method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source.

[0008] A second object of the present invention is to provide a system for analyzing soil Cd / Pb complex contaminated bimetallic isotope sources. [Means for solving the problem]

[0009] The first object of the present invention is achieved by the following aspects. The method for analyzing the source of Cd / Pb complex contamination of soil with bimetallic isotopes is as follows: Collecting soil samples and risk source samples through a sample collecting device to obtain soil samples and risk source samples; measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample, respectively, to obtain the Cd and Pb isotope ratios of the soil sample and the Cd and Pb isotope ratios of the risk source sample; Plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram; Identifying the polluted end members contaminating the farmland soil by the isotope ratio projection map, obtaining the polluted end member identification result, and further confirming the polluted end members; and calculating the relative contributions of the contaminating endmembers to obtain an isotopic source analysis.

[0010] Furthermore, the step of collecting soil samples specifically includes a step of collecting soil samples through a sample collecting device and obtaining soil samples at different distances, and the step of collecting risk source samples specifically includes a step of collecting different types of risk source samples, and the different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample.

[0011] Furthermore, the soil samples at different distances are 0-20 cm topsoil samples in farmland at different distances.

[0012] Furthermore, the step of collecting soil samples specifically includes a step of collecting soil samples through a sample collecting device and obtaining soil samples in different directions, and the step of collecting risk source samples specifically includes a step of collecting different types of risk source samples, and the different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample.

[0013] Furthermore, the Cd isotope ratio is δ 114 / 110 Cd and the Pb isotope ratio is 208 Pb / 206 Pb and 206 Pb / 207 It is Pb.

[0014] Furthermore, the Cd and Pb isotope ratios of the soil sample and the risk source sample were measured. Specifically, Cd stable isotope ratio measurement: 2.8 mL of AGMP-1M (100-200 mesh) resin was placed in a separation column, and the resin was first washed with 10 mL of 3.5N HNO3, 2N HCl + 8N HF, and 6N HCl. Ultrapure water was then added to neutralize the resin, and the sample was then added. Matrix elements inRemove with 10mL of 2N HCl, Mo (molybdenum) with 10mL of 1N HCl, Pb (lead) with 20mL of 0.3N HCl, Zn (zinc) with 20mL of 0.06N HCl, Sn (tin) with 10mL of 0.012N HCl, and finally elute and collect Cd with 20mL of 0.0012N HCl. The collected pure Cd was evaporated and dissolved in 3% HNO3 in a multi-receiver plasma mass spectrometer, and the test was completed using a multi-receiver plasma mass spectrometer (Neptune Plus MC-ICP-MS). The quality discrimination was corrected by the double dilution method, and the measured Cd stable isotope ratio results are as follows. δ 114 / 110 Cd=[( 114 Cd / 110 Cd) sample / ( 114 Cd / 110 Cd) NIST 3108 -1] × 1000, Here, ( 114 Cd / 110 Cd) sample is the measurement sample 114 Cd / 110 Cd value, ( 114 Cd / 110 Cd) NIST 3108 is standard NIST3108 114 Cd / 110 is the Cd value, Pb stable isotope ratio measurement: 1.5mL of AG1-X8 (100-200 mesh) resin was placed in a separation column, and the resin was first washed three times alternately with 6N HCl and MQ, then the impurity elements in the sample were removed with 1.5mL of 1N HBr and 1.5mL of 2N HCl, respectively, and finally Pb was eluted and collected with 1.5mL of 6N HCl. The collected pure Pb was evaporated and dried in a multi-receiver plasma mass spectrometer, dissolved in 3% HNO3, and awaited measurement. The test was completed using a multi-receiver plasma mass spectrometer (Neptune Plus MC-ICP-MS). 205 Tl / 203 The standard Tl 997 marked at Tl = 2.3871 is used as an internal standard to correct for instrument quality discrimination.

[0015] Furthermore, the step of plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram is specifically performed by plotting the Cd isotope ratios of the soil sample as the horizontal axis, the Pb isotope ratios of the soil sample as the vertical axis, the Cd isotope ratios of the risk source sample as the horizontal axis, and the Pb isotope ratios of the risk source sample as the vertical axis to obtain an isotope ratio projection diagram.

[0016] Furthermore, the steps of identifying contaminated end members that contaminate the agricultural soil using the isotope ratio projection map, obtaining identification results of the contaminated end members, and further confirming the contaminated end members specifically include identifying each risk source that is close to the isotope ratio projection point of the contaminated agricultural soil and surrounded by the isotope ratio projection point of the contaminated agricultural soil as a contaminated end member, since the isotope ratio projection point of the contaminated agricultural soil is within the range surrounded by each of the isotope ratio projection points of the contaminated agricultural soil.

[0017] Furthermore, the relative contribution ratios of the contaminated end members are calculated to obtain the isotope source analysis results, specifically, the relative contribution ratios of different contaminated end members to Cd and Pb in the contaminated farmland soil are calculated using a source analysis calculation formula.

[0018] Furthermore, the source analysis calculation formula is specifically as follows:

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[0019] The second object of the present invention is achieved by the following technical solutions. Cd / Pb mixed contamination of agricultural soil bimetallic isotope source analysis system a sampling module configured to collect soil samples and risk source samples; a sample measurement module configured to measure Cd, Pb isotope ratios of the soil sample and the risk source sample to obtain the Cd, Pb isotope ratios of the soil sample and the Cd, Pb isotope ratios of the risk source sample; a plotting module configured to plot the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection; an identification and confirmation module configured to identify contaminant end-members contaminating the agricultural soil in the isotope ratio projection, obtain a contaminant end-member identification result, and further confirm the contaminant end-members; a relative contribution calculation module configured to calculate the relative contributions of contaminating endmembers to obtain an isotope source analysis; and a result output module configured to output the final isotope source analysis results. Effect of the Invention

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention makes it possible to accurately identify Cd / Pb contaminated end members in agricultural soil based on the isotope ratio diagrams of Cd and Pb elements in agricultural soil and contaminated source samples. (2) Based on the isotopic characteristics of Cd and Pb elements in agricultural soil and contamination source samples, the present invention accurately performs quantitative analysis of the Cd / Pb contamination sources in agricultural soil, and determines the quantitative contribution rates of different contamination sources to soil Cd / Pb contamination. (3) By measuring the Cd / Pb isotopes in soil and pollution sources, the present invention develops a method for tracing the sources of soil heavy metal pollution using dual isotope fingerprinting technology, which can use two kinds of metal isotopes for mutual constraint and mutual verification. Compared with traditional methods such as multi-dimensional statistics and single isotope fingerprinting, the contribution rate of different pollution sources can be accurately determined, the analysis results are more objective and accurate, and the tracing effect on pollution sources is high. [Brief description of the drawings]

[0021] [Figure 1] 1 is a flow chart of the method for analyzing Cd / Pb complex-contaminated bimetallic isotope source in farmland soil according to the present invention. [Diagram 2] FIG. 2 is a diagram showing the identification of polluted end components of farmland soil in Example 1 of the present invention. [Diagram 3] FIG. 2 is a diagram showing the identification of polluted end components of farmland soil in Example 2 of the present invention. [Figure 4] 1 is a block diagram showing the configuration of a system for analyzing bimetallic isotope sources of Cd / Pb complex contamination in agricultural soil according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will now be described in more detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

[0023] Example 1 The method for analyzing the Cd / Pb complex contamination of agricultural soil bimetallic isotope sources is shown in Figure 1. Collecting soil samples and risk source samples through a sample collecting device to obtain soil samples and risk source samples; measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample, respectively, to obtain the Cd and Pb isotope ratios of the soil sample and the Cd and Pb isotope ratios of the risk source sample; Plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram; Identifying the polluted end members contaminating the farmland soil by the isotope ratio projection map, obtaining the polluted end member identification result, and further confirming the polluted end members; and calculating the relative contributions of the contaminating endmembers to obtain an isotopic source analysis.

[0024] Using Cd / Pb bimetallic isotopes, source analysis was carried out on Cd / Pb complex contamination of agricultural soil, as follows:

[0025] A farmland soil affected by a large lead-zinc mine in the Guizhou Karst region is selected as the implementation area, and based on the pollution characteristics of the implementation area, 0-20 centimeters of surface soil are collected from paddy fields located 200 meters, 1000 meters, and 2000 meters from the mine, and are numbered R1, R2, and R3, respectively, and potential risk source samples (tailings, mine dust, matrix, chemical fertilizer, background soil) are collected. That is, the first distance soil sample, the second distance soil sample, and the third distance soil sample are included. The first distance soil sample is a 0-20 centimeter surface soil in farmland 200 meters away. The second distance soil sample is a 0-20 centimeter surface soil in farmland 1000 meters away. The third distance soil sample is a 0-20 centimeter surface soil in farmland 2000 meters away. The first type risk source sample is tailings, the second type risk source sample is mine dust, the third type risk source sample is matrix, the fourth type risk source sample is chemical fertilizer, and the fifth type risk source sample is background soil.

[0026] After the contaminated farm soil and the contamination risk source samples were subjected to separation and purification treatment of Cd and Pb elements, respectively, the Cd and Pb isotope ratios were measured, preferably using a multi-receiver inductively coupled plasma mass spectrometer, and the test results are shown in Table 1.

[0027] [Table 1] Isotopic ratios of Cd and Pb in contaminated soil and potential risk source samples in Example 1 [Table 1]

[0028] In this example, among the agricultural soil samples and potential risk source samples, as shown in FIG. 114 / 110 Cd is the horizontal axis, 208 Pb / 206 Pb is plotted on the vertical axis. As can be seen from the figure, the heavy metal pollution sources of farmland soil are mine dust, background soil, and tailings, and among these three pollution end-components, the pollution sources from mines, including tailings and mine dust, are relatively significant in their influence of pollution, and the contribution of chemical fertilizers and matrix can be excluded. It was suggested that the influence of mining on farmland soil in this target study area is significant, and the influence of agricultural activity pollution sources is almost concealed.

[0029] According to the results of these contaminated end-member identifications, the contaminated end-members of the agricultural soil were mine dust (A), tailings (B), and background soil (C). 114 / 110 Cd and 208 Pb / 206 Pb is introduced into the pollution contribution calculation formula.

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[0030] The calculation results are shown in Table 2. Soils R1 and R2 are close to the mine, and the contribution of contamination from mine dust was 79.06% and 54.69%, respectively. Soil R3 is relatively far from the mine, and is mainly contaminated from background soil, with a contribution rate of 53.36%.

[0031] Example 2 This embodiment has the same structure as the first embodiment except for the following features. A farmland soil affected by a large polymetallic ore field in South China is selected as the implementation area. Based on the pollution characteristics of the implementation area, 0-20 cm of surface soil is randomly collected from four surrounding paddy fields around the ore field, and numbered P1, P2, P3, and P4, respectively, and potential risk source samples (mine wastewater precipitation, atmospheric precipitation, matrix, chemical fertilizer, background soil) are collected. That is, the four surrounding paddy fields include the first direction, the second direction, the third direction, and the fourth direction. The first type risk source sample is mine wastewater precipitation, the second type risk source sample is atmospheric precipitation, the third type risk source sample is matrix, the fourth type risk source sample is chemical fertilizer, and the fifth type risk source sample is background soil.

[0032] After the contaminated farmland soil and the contamination risk source samples were respectively subjected to separation and purification treatment of Cd and Pb elements, the Cd and Pb isotope ratios were measured, preferably using a multi-receiver inductively coupled plasma mass spectrometer, and the test results are shown in Table 3.

[0033] [Table 3] Cd and Pb isotope ratios of contaminated soil and potential risk source samples in Example 2 [Table 3]

[0034] In this example, among the agricultural soil samples and potential risk source samples, as shown in FIG. 114 / 110 Cd is the horizontal axis, 206 Pb / 207 Pb is plotted on the vertical axis. As can be seen from the figure, the sources of heavy metal contamination in the contaminated agricultural soil are four end members: mine wastewater precipitation, atmospheric deposition, matrix, and background soil. The contamination contribution of chemical fertilizers in agricultural activities can be excluded compared with the influence from mining activities.

[0035] According to the above results of end-member identification, the contaminated end-members of the agricultural soil were mine wastewater deposition (A), atmospheric deposition (B), matrix (C), and background soil (D). 114 / 110 Cd and 206 Pb / 207 Pb is introduced into the pollution contribution calculation formula.

number

[0036] The calculation results obtained are shown in Table 4. In the South China Red Earth area, where heavy metal activity is strong, the contribution of anthropogenic active heavy metal pollution was dominant, and the contribution of mine wastewater deposition and atmospheric deposition was more than 97% of the pollution contribution rate in all four agricultural soils, while the contribution of natural sources, including parent material and background soil, was low.

[0037] [Table 4] Contamination end member contribution amount (%) of Example 2 [Table 4]

[0038] As described above, the technical solution of the present invention uses Cd / Pb isotopes to parallelize soil Cd / Pb complex pollution source analysis, which can accurately identify the polluted end members of agricultural soil in different regions and calculate the relative contribution rate. Two specific examples of the present invention are carried out in the southwest karst region and the southern China red earth region, which have two geological backgrounds and large differences in heavy metal activity. The polluted end members of agricultural soil are identified by Cd-Pb isotope projection map, and the relative contribution rate of each polluted end member is calculated. The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples.

[0039] Example 3 The agricultural soil Cd / Pb complex contamination bimetal isotope source analysis system is shown in Figure 4. a sampling module configured to collect soil samples and risk source samples; a sample measurement module configured to measure Cd, Pb isotope ratios of the soil sample and the risk source sample to obtain the Cd, Pb isotope ratios of the soil sample and the Cd, Pb isotope ratios of the risk source sample; a plotting module configured to plot the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection; an identification and confirmation module configured to identify contaminant end-members contaminating the agricultural soil in the isotope ratio projection, obtain an identification result of the contaminant end-members, and further confirm the contaminant end-members; a relative contribution calculation module configured to calculate the relative contributions of contaminating endmembers to obtain an isotope source analysis; and a result output module configured to output the final isotope source analysis results.

[0040] The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above-mentioned embodiments. Any changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principles of the present invention are considered to be equivalent replacement methods and are included in the protection scope of the present invention.

[0041] (Additional Note) (Appendix 1) A method for analyzing soil Cd / Pb complex bimetallic isotope sources, comprising: Collecting soil samples and risk source samples through a sample collecting device to obtain soil samples and risk source samples; measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample, respectively, to obtain the Cd and Pb isotope ratios of the soil sample and the Cd and Pb isotope ratios of the risk source sample; Plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram; Identifying the polluted end members contaminating the farmland soil by the isotope ratio projection map, obtaining the polluted end member identification result, and further confirming the polluted end members; calculating the relative contributions of the contaminating endmembers to obtain an isotopic source analysis; The method for analyzing soil Cd / Pb complex contamination bimetallic isotope source is characterized by the following.

[0042] (Appendix 2) The step of collecting soil samples includes the steps of collecting soil samples through a sampler and obtaining soil samples at different distances; The step of collecting risk source samples includes collecting different types of risk source samples; The different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample; 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0043] (Appendix 3) The step of collecting soil samples includes the steps of collecting soil samples through a sampler to obtain soil samples in different orientations; The step of collecting risk source samples includes collecting different types of risk source samples; The different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample; 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0044] (Appendix 4) The Cd isotope ratio is δ 114 / 110 Cd and the Pb isotope ratio is 208 Pb / 206 Pb and 206 Pb / 207 Pb, 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0045] (Appendix 5) The step of measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample includes a step of measuring a Cd stable isotope ratio and a step of measuring a Pb stable isotope ratio; In the above Cd stable isotope ratio measurement, 2.8 mL of AG MP-1M resin was placed in the separation column, and the resin was first washed with 10 mL of 3.5N HNO3, 2N HCl + 8N HF, and 6N HCl. Ultrapure water was then added to neutralize the resin, and the sample was then added. Matrix elements in Remove with 10mL of 2N HCl, Mo with 10mL of 1N HCl, Pb with 20mL of 0.3N HCl, Zn with 20mL of 0.06N HCl, Sn with 10mL of 0.012N HCl, and finally elute and collect Cd with 20mL of 0.0012N HCl. The collected pure Cd was evaporated and dried in a multi-receiving plasma mass spectrometer, dissolved in 3% HNO3, and awaited measurement. The test was completed using a multi-receiving plasma mass spectrometer, and the quality discrimination was corrected by the double dilution method. The measured Cd stable isotope ratio results are as follows: δ 114 / 110 Cd=[( 114 Cd / 110 Cd) sample / ( 114 Cd / 110 Cd) NIST 3108 -1] × 1000, Here, ( 114 Cd / 110 Cd) sample is the measurement sample 114 Cd / 110 Cd value, ( 114 Cd / 110 Cd) NIST 3108 is standard NIST3108 114 Cd / 110 is the Cd value, In the measurement of the Pb stable isotope ratio, 1.5mL of AG1-X8 resin was placed in a separation column, and the resin was first washed three times alternately with 6N HCl and MQ, then the impurity elements in the sample were removed with 1.5mL of 1N HBr and 1.5mL of 2N HCl, respectively, and finally the Pb was eluted and collected with 1.5mL of 6N HCl. The collected pure Pb was evaporated and dried in a multi-receiver plasma mass spectrometer, dissolved in 3% HNO3, and awaited measurement. The test was completed using a multi-receiver plasma mass spectrometer. 205 Tl / 203 The standard Tl 997 marked at Tl=2.3871 is used as an internal standard to correct for instrument quality discrimination. 5. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 4.

[0046] (Appendix 6) The step of plotting the Cd and Pb isotope ratios of the soil sample as coordinates and the Cd and Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram includes the steps of plotting the Cd isotope ratios of the soil sample as a horizontal axis, plotting the Pb isotope ratios of the soil sample as a vertical axis, plotting the Cd isotope ratios of the risk source sample as a horizontal axis, and plotting the Pb isotope ratios of the risk source sample as a vertical axis to obtain an isotope ratio projection diagram, the horizontal axis and the vertical axis being coincident, the horizontal axis being the Cd isotope, and the vertical axis being the Pb isotope; 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0047] (Appendix 7) The step of identifying contaminated end members contaminating the farmland soil by the isotope ratio projection map, obtaining the identification result of the contaminated end members, and further confirming the contaminated end members includes the step of identifying each risk source that is close to the isotope ratio projection point of the contaminated farmland soil and surrounded by the isotope ratio projection point of the contaminated farmland soil as a contaminated end member, since the isotope ratio projection point of the contaminated farmland soil is within the range surrounded by each isotope ratio projection point of the contaminated end member, 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0048] (Appendix 8) The step of calculating the relative contribution ratio of the contaminated end members and obtaining the isotope source analysis result includes the step of calculating the relative contribution ratio of different contaminated end members to Cd and Pb in the contaminated farmland soil by a source analysis calculation formula; 2. A method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

[0049] (Appendix 9) The source analysis formula is as follows:

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[0050] (Appendix 10) A soil Cd / Pb complex contamination bimetal isotope source analysis system, a sampling module configured to collect soil samples and risk source samples; a sample measurement module configured to measure Cd, Pb isotope ratios of the soil sample and the risk source sample to obtain the Cd, Pb isotope ratios of the soil sample and the Cd, Pb isotope ratios of the risk source sample; a plotting module configured to plot the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection; an identification and confirmation module configured to identify contaminant end-members contaminating the agricultural soil in the isotope ratio projection, obtain a contaminant end-member identification result, and further confirm the contaminant end-members; a relative contribution calculation module configured to calculate the relative contributions of contaminating endmembers to obtain an isotope source analysis; and a result output module configured to output a final isotope source analysis result. This is a system for determining the source of bimetallic isotopes in soil containing Cd / Pb.

Claims

1. A method for analyzing soil Cd / Pb complex bimetallic isotope sources, comprising: Collecting soil samples and risk source samples through a sample collecting device, respectively, to obtain the soil samples and the risk source samples, respectively; Measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample, respectively, to obtain the Cd and Pb isotope ratios of the soil sample and the Cd and Pb isotope ratios of the risk source sample; Plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection. Identifying a contamination source that contaminates agricultural soil by the isotope ratio projection map, obtaining an identification result of the contamination source, and further confirming the contamination source; calculating the relative contributions of the contamination sources to obtain an isotopic source analysis; The step of plotting the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram includes a step of plotting the Cd isotope ratios of the soil sample as a horizontal axis, plotting the Pb isotope ratios of the soil sample as a vertical axis, plotting the Cd isotope ratios of the risk source sample as a horizontal axis, and plotting the Pb isotope ratios of the risk source sample as a vertical axis to obtain one isotope ratio projection diagram, wherein the horizontal axis and the vertical axis are coincident, the horizontal axis is the Cd isotope, and the vertical axis is the Pb isotope. A method for analyzing a soil bimetallic isotope source containing Cd / Pb as a complex contaminant, comprising:

2. The step of collecting the soil samples includes collecting the soil samples through the sample collecting device to obtain soil samples at different distances; The step of collecting risk source samples includes collecting different types of risk source samples; The different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample; 2. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

3. The step of collecting the soil samples includes collecting the soil samples through the sample collecting device to obtain soil samples in different orientations; The step of collecting risk source samples includes collecting different types of risk source samples; The different types of risk source samples include a first type risk source sample, a second type risk source sample, a third type risk source sample, a fourth type risk source sample and a fifth type risk source sample; 2. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

4. The Cd isotope ratio is δ １１４／１１０ Cd, and the Pb isotope ratio is ２０８ Pb / ２０６ Pb and ２０６ Pb / ２０７ Pb, 2. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

5. The step of measuring the Cd and Pb isotope ratios of the soil sample and the risk source sample includes a step of measuring a Cd stable isotope ratio and a step of measuring a Pb stable isotope ratio; In the Cd stable isotope ratio measurement, 2.8 mL of AG MP-1M resin was placed in a separation column, and the AG MP-1M resin was first washed with 10 mL of 3.5N HNO3, 2N HCl + 8N HF and 6N HCl, and ultrapure water was added so that the AG MP-1M resin became neutral. Then, the soil sample or the risk source sample was placed in the separation column, and the substrate elements in the soil sample or the risk source sample were removed with 10 mL of 2N HCl, Mo in the soil sample or the risk source sample was removed with 10 mL of 1N HCl, Pb was removed with 20 mL of 0.3N HCl, Zn was removed with 20 mL of 0.06N HCl, Sn was removed with 10 mL of 0.012N HCl, and finally, 20 mL of 0.0012N HCl was removed with 20 mL of 0.0012N HCl. Cd was dissolved in HCl and collected. The collected pure Cd was dried and dissolved in 3% HNO3 for measurement in a multi-receiver plasma mass spectrometer. The test was completed using a multi-receiver plasma mass spectrometer, and the quality difference was corrected by the double dilution method. The results of the measured Cd stable isotope ratio are as follows: δ １１４／１１０ Cd=[( １１４ Cd / １１０ Cd) ｓａｍｐｌｅ / ( １１４ Cd / １１０ Cd) ＮＩＳＴ ３１０８ -1]×1000、 Here, ( １１４ Cd / １１０ Cd) ｓａｍｐｌｅ is the measurement sample １１４ Cd / １１０ Cd value, ( １１４ Cd / １１０ Cd) ＮＩＳＴ ３１０８ is the standard NIST 3108 １１４ Cd / １１０ is the Cd value, In the measurement of the Pb stable isotope ratio, 1.5 mL of AG1-X8 resin is placed in a separation column, and the AG1-X8 resin is first washed three times alternately with 6N HCl and MQ, and then the soil sample or the risk source sample is placed in the separation column, and the impurity elements in the soil sample or the risk source sample are removed with 1.5 mL of 1N HBr and 1.5 mL of 2N HCl, respectively, and finally the Pb is eluted and collected with 1.5 mL of 6N HCl, and the collected pure Pb is evaporated and dried in a multi-receiving plasma mass spectrometer, dissolved in 3% HNO3, and awaits measurement, and the test is completed using the multi-receiving plasma mass spectrometer; ２０５ Tl / ２０３ The standard Tl 997 marked at Tl = 2.3871 is used as an internal standard to correct for instrument quality discrimination.

5. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 4.

6. The step of identifying contamination sources that contaminate agricultural soil using the isotope ratio projection map, obtaining the contamination source identification result, and further confirming the contamination source includes a step of identifying each risk source that is close to the isotope ratio projection point of the contaminated agricultural soil and surrounded by the isotope ratio projection points of each of the contamination sources as the contamination source, since the isotope ratio projection point of the contaminated agricultural soil is within a range surrounded by the isotope ratio projection points of each of the contamination sources; 2. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

7. The step of calculating the relative contribution rate of the contamination sources and obtaining an isotope source analysis result includes a step of calculating the relative contribution rate of the different contamination sources to Cd and Pb in the contaminated agricultural soil by a source analysis calculation formula; 2. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 1.

8. The source analysis formula is as follows: [0010] where A, B, C, and D represent the four contamination sources, respectively, and δ １１４／１１０ Cd represents the Cd isotope ratio, δ １１４／１１０ Cd Ａ , δ １１４／１１０ Cd Ｂ , δ １１４／１１０ Cd Ｃ , δ １１４／１１０ Cd Ｄ represents the Cd isotope ratios of the four contamination sources A, B, C, and D, respectively; [0025] represents the Pb isotope ratio of the contaminated soil, [0030] represents the Pb isotope ratios of the four contamination sources A, B, C, and D, respectively, and when m = 208, n = 206, or when m = 206, n = 207, X Ａ , X Ｂ , X Ｃ , X Ｄ represent the contribution rates of the four pollution sources A, B, C, and D, respectively. The method for analyzing a soil Cd / Pb complex contaminated bimetallic isotope source according to claim 7.

9. A soil Cd / Pb complex contamination bimetallic isotope source analysis system, comprising: a sampling module configured to collect soil samples and risk source samples; a sample measurement module configured to measure the Cd, Pb isotope ratios of the soil sample and the risk source sample to obtain the Cd, Pb isotope ratios of the soil sample and the Cd, Pb isotope ratios of the risk source sample; a plotting module configured to plot the Cd, Pb isotope ratios of the soil samples as coordinates and the Cd, Pb isotope ratios of the risk source samples as coordinates to obtain an isotope ratio projection; an identification and confirmation module configured to identify a contamination source that contaminates agricultural soil by the isotope ratio projection map, obtain a contamination source identification result, and further confirm the contamination source; a relative contribution calculation module configured to calculate the relative contributions of the contamination sources to obtain an isotope source analysis result; a result output module configured to output a final isotope source analysis result; The plotting module configured to plot the Cd, Pb isotope ratios of the soil sample as coordinates and the Cd, Pb isotope ratios of the risk source sample as coordinates to obtain an isotope ratio projection diagram includes plotting the Cd isotope ratios of the soil sample as a horizontal axis, plotting the Pb isotope ratios of the soil sample as a vertical axis, plotting the Cd isotope ratios of the risk source sample as a horizontal axis, and plotting the Pb isotope ratios of the risk source sample as a vertical axis to obtain one isotope ratio projection diagram, wherein the horizontal axis and the vertical axis are coincident, the horizontal axis is Cd isotopes, and the vertical axis is Pb isotopes. A soil Cd / Pb complex contamination bimetallic isotope source analysis system.

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