A method for calculating the contribution rate of atmospheric deposition through different exposure pathways to the enrichment of cadmium in grains

Abstract

The application provides a method for calculating the contribution rate of atmospheric deposition to the enrichment of Cd in grains through different exposure approaches, and belongs to the technical field of pollution source investigation. The method can obtain the Cd isotope composition of different parts of grains through setting field tests and greenhouse tests, and can calculate the contribution rates f2 and f1 of atmospheric deposition and original Cd in soil to Cd in a part of grains through combining a Cd isotope mixing model. The method provided by the application can more accurately trace the absorption and transport process of Cd isotopes by crops.

Description

Technical Field

[0001] This invention belongs to the field of pollution source investigation technology, and in particular relates to a method for calculating the contribution rate of atmospheric deposition to Cd enrichment in grains through different exposure pathways. Background Technology

[0002] With the rapid development of the world economy, a large amount of anthropogenic carbon dioxide (Cd) is emitted into the atmosphere. Non-ferrous metal smelting accounts for 40.6% of total anthropogenic Cd emissions, making it the largest source of atmospheric Cd and increasing the burden of atmospheric Cd on the Earth's surface environment. Furthermore, atmospheric deposition has high bioavailability, easily accumulating in crops and entering the food chain.

[0003] The main pathways for the absorption of atmospheric Cd by cereal crops include leaf absorption and root absorption. Unlike the extensive research on root metal translocation, only a few studies have attempted to explore and examine leaf absorption of atmospheric heavy metals. Furthermore, significant gaps remain in research regarding the primary pathways of Cd absorption and translocation from atmospheric deposition by cereal crops' roots or leaves.

[0004] The stable isotopes of cadmium (Cd) provide a novel technique for tracking the migration and transformation of Cd in the environment and crops. In high-temperature industrial processes, Cd isotope fractionation manifests as enrichment of heavy isotopes in slag and light isotopes in dust. This is because lighter Cd isotopes are absorbed by the gas phase (dust), while heavier Cd remains in the residual phase (slag). Atmospheric deposition of Cd may be the atmospheric source of Cd in crops. However, during Cd uptake by crops, Cd isotopes fractionate from roots to rice grains, gradually becoming heavier, making it more difficult to trace the source of Cd in crop tissues.

[0005] Currently, research on Cd isotopes in cereal crops mainly focuses on the factors influencing the fractionation of Cd isotopes within the crop, while research on tracing the Cd source in cereals has not yet been successful. Therefore, using Cd isotopes to more accurately trace the absorption and translocation of Cd in crops is particularly important. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for calculating the contribution rate of atmospheric deposition to Cd enrichment in grains through different exposure pathways. This method can calculate the contribution rate of atmospheric deposition to various parts of the grain through root exposure or leaf exposure.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for calculating the contribution of atmospheric deposition to Cd enrichment in cereals through different exposure pathways, comprising the following steps:

[0009] (1) Collect surface soil from non-atmospheric deposition areas as test soil, and collect particles from atmospheric deposition areas as raw materials for exposure treatment.

[0010] (2) Field experiments and greenhouse experiments were set up respectively. In the field experiment, a control group, a root exposure treatment group and a leaf exposure treatment group were set up. In the greenhouse experiment, a blank treatment group and an exposure treatment group were set up. The exposure treatment group included root exposure L treatment group, root exposure H treatment group, leaf exposure L treatment group and leaf exposure H treatment group.

[0011] (3) Grains were planted in each treatment group. After the grains matured, the Cd concentration and Cd isotope composition of each part of the grains were measured.

[0012] (4) Calculate the Cd contribution rate s of particles in the atmospheric deposition zone to different parts of the grain in the greenhouse experiment according to formula (1). If s ≥ 85% compared to the blank treatment group, and the Cd isotope composition of different parts of the grain obtained by different exposure methods is not significantly different, then the Cd isotope fractionation value under different exposure treatments is defined as the same, which is a constant value, that is, the Cd isotope fractionation value will not change with the change of particle dosage; and calculate the Cd isotope fractionation value of particles in the atmospheric deposition zone to different parts of the grain through different exposure methods based on the Cd isotope composition value measured in the greenhouse experiment, that is, obtain Δ 114 / 110 Cd 根-颗粒 Δ 114 / 110 Cd 部位-根 ", Δ 114 / 110 Cd 叶-颗粒 Δ 114 / 110 Cd 部位-叶 ”;

[0013] The calculation of Cd isotope fractionation values ​​is based on Δ 114 / 110 Cd A-B =δ 114 / 110 Cd A -δ 114 / 110 Cd B Calculated;

[0014] S=((Cd 暴露处理组 -Cd 空白处理组 ) / Cd 暴露处理组 )×100% formula (1);

[0015] (5) Assuming that under the same grain variety, soil, and planting pattern, the Cd isotope fractionation value (ΔCd) from the soil to a certain part of the grain root is different from that of Cd originating from the soil. 114 / 110 Cd 部位-根 If δ is constant, then the isotopic fractionation value passes through the root (δ) in the control group of the field experiment. 114 / 110 Cd根-对照组 ) and any part (δ) 114 / 110 Cd 部位-对照组 The Cd isotope composition of ) is used to calculate, thus obtaining formula (2): Δ 114 / 110 Cd 部位-根 '=δ 114 / 110 Cd 部位-对照组 -δ 114 / 110 Cd 根-对照组

[0016] =δ 114 / 110 Cd 部位-根部暴露处理组 '-δ 114 / 110 Cd 根-根部暴露处理组 '

[0017] =δ 114 / 110 Cd 部位-叶面暴露处理组 '-δ 114 / 110 Cd 根-叶面暴露处理组 '

[0018] Formula (2);

[0019] Since the grain roots grew in the same soil during the field experiment, the Cd isotopic composition contributed by the Cd from the original Cd in the soil was the same.

[0020] δ 114 / 110 Cd 根-对照组 =δ 114 / 110 Cd 根-根部暴露处理组 '=δ 114 / 110 Cd 根-叶面暴露处理组 ';

[0021] Formula (3);

[0022] Substituting formula (3) into formula (2), we get:

[0023] δ 114 / 110 Cd 部位-根部暴露处理组 '=δ 114 / 110 Cd 部位-叶面暴露处理组 '

[0024] =Δ 114 / 110 Cd 部位-根 '+δ 114 / 110 Cd 根-对照组

[0025] Formula (4);

[0026] (6) Since all the Cd in the roots and leaves of the grain in the greenhouse experiment came from the grain particles, the fractionation value of Cd absorbed by the roots and leaves of the grain from the grain particles under different exposure doses is defined as: Δ 114 / 110 Cd root- 颗粒 and Δ 114 / 110 Cd 叶-颗粒And the fractionation value Δ during Cd transport between different parts 114 / 110 Cd 部位-根 "and Δ 114 / 110 Cd 部位-叶 "Unchanged, proceed to the next calculation:"

[0027] Since the isotopic fractionation value of Cd has been determined in part of equation (1) to be constant and does not change with the amount of particles used, it is assumed that in the field experiment, the absorption and translocation of atmospheric Cd by the roots (or leaves) of the grain caused by atmospheric deposition is the same as that caused by the absorption and translocation of particle Cd by the roots (or leaves) of the grain in the greenhouse experiment. Therefore:

[0028] δ 114 / 110 Cd 根-根部暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-大气沉降

[0029] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-颗粒

[0030] Formula (5);

[0031] δ 114 / 110 Cd 叶-叶面暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-大气沉降

[0032] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-颗粒

[0033] Formula (6);

[0034] Similar to the principle of formula (4): In field experiments, the Cd isotopic composition of any part can be calculated from the Cd isotopic composition of the root or leaf and the Cd isotopic fractionation value within the grain:

[0035] δ 114 / 110 Cd 部位-根部暴露处理组 =δ 114 / 110 Cd 根-根部暴露处理组 +Δ 114 / 110 Cd 部位-根 "

[0036] Formula (7);

[0037] δ 114 / 110 Cd 部位-叶面暴露处理组 =δ114 / 110 Cd 叶-叶面暴露处理组 +Δ 114 / 110 Cd 部位-叶 "

[0038] Formula (8);

[0039] (7) Calculate the contribution rates f2 and f1 of atmospheric deposition and original soil Cd to Cd in a certain part of the grain based on the Cd isotope mixing model.

[0040] Due to δ 114 / 110 Cd 部位 =f1×δ 114 / 110 Cd 部位 '+f2×δ 114 / 110 Cd 部位 "

[0041] 1 = f1 + f2

[0042] Formula (9);

[0043] The contribution rate of atmospheric deposition to Cd in a certain part of the grain can be calculated by combining formula (9) with the above formulas (4), (5) and (7) or formulas (4), (6) and (8).

[0044] In the formula,

[0045] S represents the contribution rate of atmospheric deposition particles to Cd in various parts of the grain, calculated using the mass balance method in a greenhouse experiment.

[0046] Δ 114 / 110 Cd 根 - 颗粒 The Cd isotope fractionation value represents the Cd isotope fractionation that occurs when particles of atmospheric deposition are absorbed by the roots of grains during greenhouse experiments.

[0047] Δ 114 / 110 Cd 部位-根 "This represents the Cd isotope fractionation value that occurs when Cd absorbed by the roots from atmospheric particles is transported from the roots to a certain part of the grain during greenhouse experiments."

[0048] Δ 114 / 110 Cd 叶-颗粒 The Cd isotope fractionation value represents the amount of particles that are absorbed by the leaves of grains during atmospheric deposition in a greenhouse experiment.

[0049] Δ 114 / 110 Cd 部位-叶 "This represents the Cd isotope fractionation value contributed by the Cd from atmospheric deposition particles that are transported from the leaves to a certain part of the grain during the greenhouse experiment, which is the Cd absorbed by the leaves from atmospheric deposition particles."

[0050] Cd 暴露处理组Cd concentration in a specific part of the grain in the exposure treatment group representing the greenhouse experiment;

[0051] Cd 空白处理组 This represents the Cd concentration in a specific part of the grain in the blank treatment group of the greenhouse experiment;

[0052] Δ 114 / 110 Cd 部位-根 'Represents the Cd isotope fractionation value that occurs when Cd absorbed from the soil by the roots is transported from the roots to a certain part of the grain.'

[0053] δ 114 / 110 Cd 根-对照组 The Cd isotope composition of cereal roots represents that of the control group.

[0054] δ 114 / 110 Cd 部位-对照组 The Cd isotope composition of a certain part of the grain in the control group;

[0055] δ 114 / 110 Cd 部位-根部暴露处理组 'This represents the Cd isotopic composition of a certain part of the grain in the root exposure treatment group, which is contributed by the original Cd in the soil;'

[0056] δ 114 / 110 Cd 根-根部暴露处理组 'This represents the Cd isotopic composition of cereal roots in the root exposure treatment group, which is derived from the original Cd contribution from the soil.'

[0057] δ 114 / 110 Cd 部位-叶面暴露处理组 'Represents the Cd isotopic composition of a certain part of the grain in the foliar exposure treatment group, which is contributed by the original Cd in the soil;'

[0058] δ 114 / 110 Cd 根-叶面暴露处理组 'This represents the Cd isotopic composition of cereal roots from the original Cd in the soil in the foliar exposure treatment group;'

[0059] δ 114 / 110 Cd 根-根部暴露处理组 "This represents the Cd isotopic composition of cereal roots from atmospheric deposition contributed by Cd particles in the root exposure treatment group."

[0060] δ 114 / 110 Cd 叶-叶面暴露处理组 "Represents the Cd isotopic composition of cereal leaves from atmospheric deposition, contributed by Cd particles in the foliar exposure treatment group;

[0061] δ 114 / 110 Cd 部位-根部暴露处理组 "This represents the Cd isotopic composition of a portion of the grain from atmospheric deposition in the root exposure treatment group."

[0062] δ114 / 110 Cd 部位-叶面暴露处理组 "This represents the Cd isotopic composition of a certain part of the grain from atmospheric deposition in the leaf exposure treatment group."

[0063] δ 114 / 110 Cd 部位 Cd isotope composition of a specific part of a grain in different exposure groups;

[0064] δ 114 / 110 Cd 部位 'Represents the Cd isotopic composition of a certain part of the grain in different exposure groups, which is derived from the original Cd contribution from the soil;

[0065] δ 114 / 110 Cd 部位 "This represents the Cd isotopic composition of a portion of grain from atmospheric deposition, representing the Cd contribution from particles in different exposure groups."

[0066] δ 114 / 110 Cd 大气沉降 The Cd isotopic composition of particles deposited in the atmospheric deposition zone as measured in field experiments;

[0067] Δ 114 / 110 Cd 根-大气沉降 This represents the Cd isotope fractionation value that occurs when atmospheric particles are absorbed by the roots of grains during field experiments in atmospheric deposition zones.

[0068] f1 is the proportion of the original Cd from the soil that contributes to a certain part of the cereal crop;

[0069] f2 is the proportion of Cd from particles originating from atmospheric deposition that contributes to a specific part of cereal crops;

[0070] The parts mentioned include one of the following: roots, leaves, and rice grains.

[0071] Preferably, the non-atmospheric deposition zone in step (1) is an area more than 36 km away from the source of air pollution; the atmospheric deposition zone is an area 0 to 2 km below the ground wind direction of the source of air pollution; the depth of the surface soil is 0.1 to 20 cm; the particles in the atmospheric deposition zone are particles in the pulse particle trap of the pollution source factory, and the particles are ground to below 50 μm during use.

[0072] Preferably, in step (2), the control group and the root exposure treatment group set up in the field experiment are both placed in a non-atmospheric deposition area, while the leaf exposure treatment group is placed in an atmospheric deposition area; the root exposure treatment group set up in the field experiment is given polluted water collected by an atmospheric deposition collection device; the soil surface of the leaf exposure treatment group set up in the field experiment is covered with a geomembrane to prevent atmospheric deposition from entering the soil.

[0073] Preferably, the atmospheric sedimentation collection device is an atmospheric sedimentation collection tank, and the polluted water is the liquid obtained by cleaning the atmospheric sedimentation collection tank.

[0074] Preferably, in step (2), the root exposure L treatment group and the root exposure H treatment group set in the greenhouse experiment add particles collected from the atmospheric deposition zone to the soil before planting the grain, and the leaf exposure L treatment group and the leaf exposure H treatment group set in the greenhouse experiment apply the particles collected from the atmospheric deposition zone to the front surface of the leaves when the grain grows to the jointing stage; the greenhouse experiment is carried out in an environment with a room temperature of 25-35℃.

[0075] Preferably, the grain is rice.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] By obtaining Cd isotope fractionation values ​​from greenhouse experiments, which show the adsorption of particles by the roots and leaves of cereal crops and their subsequent transport within the plant, the parameters of the Cd isotope mixing model can be corrected. This solves the current problem of not being able to use Cd isotopes to trace the source of Cd in plants. Combined with field experiment design, the exposure methods of atmospheric deposition to crops can be further distinguished into root exposure and leaf exposure. This allows for the accurate calculation of the contribution rate of atmospheric deposition to various parts of cereal crops through different exposure pathways. Attached Figure Description

[0078] Figure 1 The concentration of Cd in rice grains measured in a greenhouse experiment;

[0079] Figure 2 The concentration of Cd in rice leaves was measured in a greenhouse experiment.

[0080] Figure 3 The concentration of Cd in rice roots was measured in a greenhouse experiment.

[0081] Figure 4 The Cd isotopic composition of rice roots, leaves, and grains was measured in a greenhouse experiment.

[0082] Figure 5 The Cd isotope composition of rice roots, leaves and rice grains was measured in a field experiment. Detailed Implementation

[0083] This invention provides a method for calculating the contribution of atmospheric deposition to Cd enrichment in cereals through different exposure pathways, comprising the following steps:

[0084] (1) Collect surface soil from non-atmospheric deposition areas as test soil, and collect particles from atmospheric deposition areas as raw materials for exposure treatment.

[0085] (2) Field experiments and greenhouse experiments were set up respectively. In the field experiment, a control group, a root exposure treatment group, and a leaf exposure treatment group were set up. In the greenhouse experiment, a blank treatment group and an exposure treatment group were set up. The exposure treatment group included root exposure L treatment group, root exposure H treatment group, leaf exposure L treatment group, and leaf exposure H treatment group.

[0086] (3) Grains were planted in each treatment group. After the grains matured, the Cd concentration and Cd isotope composition of each part of the grains were measured.

[0087] (4) Calculate the Cd contribution rate s of particles in the atmospheric deposition zone to different parts of the grain in the greenhouse experiment according to formula (1). If s ≥ 85% compared to the blank treatment group, and the Cd isotope composition of different parts of the grain obtained by different exposure methods is not significantly different, then the Cd isotope fractionation value under different exposure treatments is defined as the same, which is a constant value, that is, the Cd isotope fractionation value will not change with the change of particle dosage; and calculate the Cd isotope fractionation value of particles in the atmospheric deposition zone to different parts of the grain through different exposure methods based on the Cd isotope composition value measured in the greenhouse experiment, that is, obtain Δ 114 / 110 Cd 根-颗粒 Δ 114 / 110 Cd 部位-根 ", Δ 114 / 110 Cd 叶-颗粒 Δ 114 / 110 Cd 部位-叶 ”;

[0088] The calculation of Cd isotope fractionation values ​​is based on Δ 114 / 110 Cd A-B =δ 114 / 110 Cd A -δ 114 / 110 Cd B Calculated;

[0089] S=((Cd 暴露处理组 -Cd 空白处理组 ) / Cd 暴露处理组 )×100% formula (1);

[0090] (5) Assuming that under the same grain variety, soil, and planting pattern, the Cd isotope fractionation value (ΔCd) from the soil to a certain part of the grain root is different from that of Cd originating from the soil. 114 / 110 Cd 部位-根 If δ is constant, then the isotopic fractionation value passes through the root (δ) in the control group of the field experiment. 114 / 110 Cd 根-对照组 ) and any part (δ) 114 / 110 Cd 部位-对照组 The Cd isotope composition of ) is used to calculate, thus obtaining formula (2): Δ114 / 110 Cd 部位-根 '=δ 114 / 110 Cd 部位-对照组 -δ 114 / 110 Cd 根-对照组

[0091] =δ 114 / 110 Cd 部位-根部暴露处理组 '-δ 114 / 110 Cd 根-根部暴露处理组 '

[0092] =δ 114 / 110 Cd 部位-叶面暴露处理组 '-δ 114 / 110 Cd 根-叶面暴露处理组 '

[0093] Formula (2);

[0094] Since the grain roots grew in the same soil during the field experiment, the Cd isotopic composition contributed by the Cd from the original Cd in the soil was the same.

[0095] δ 114 / 110 Cd 根-对照组 =δ 114 / 110 Cd 根-根部暴露处理组 '=δ 114 / 110 Cd 根-叶面暴露处理组 ';

[0096] Formula (3);

[0097] Substituting formula (3) into formula (2), we get:

[0098] δ 114 / 110 Cd 部位-根部暴露处理组 '=δ 114 / 110 Cd 部位-叶面暴露处理组 '

[0099] =Δ 114 / 110 Cd 部位-根 '+δ 114 / 110 Cd 根-对照组

[0100] Formula (4);

[0101] (6) Since all the Cd in the roots and leaves of the grain in the greenhouse experiment came from the grain particles, the fractionation value of Cd absorbed by the roots and leaves of the grain from the grain particles under different exposure doses is defined as: Δ 114 / 110 Cd 根-颗粒 and Δ 114 / 110 Cd 叶-颗粒 And the fractionation value Δ during Cd transport between different parts 114 / 110 Cd 部位-根 "and Δ 114 / 110 Cd 部位-叶"Unchanged, proceed to the next calculation:"

[0102] Since the isotopic fractionation value of Cd has been determined in part of equation (1) to be constant and does not change with the amount of particles used, it is assumed that in the field experiment, the absorption and translocation of atmospheric Cd by the roots (or leaves) of the grain caused by atmospheric deposition is the same as that caused by the absorption and translocation of particle Cd by the roots (or leaves) of the grain in the greenhouse experiment. Therefore:

[0103] δ 114 / 110 Cd 根-根部暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-大气沉降

[0104] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-颗粒

[0105] Formula (5);

[0106] δ 114 / 110 Cd 叶-叶面暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-大气沉降

[0107] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-颗粒

[0108] Formula (6);

[0109] Similar to the principle of formula (4): In field experiments, the Cd isotopic composition of any part can be calculated from the Cd isotopic composition of the root or leaf and the Cd isotopic fractionation value within the grain:

[0110] δ 114 / 110 Cd 部位-根部暴露处理组 =δ 114 / 110 Cd 根-根部暴露处理组 +Δ 114 / 110 Cd 部位-根 "

[0111] Formula (7);

[0112] δ 114 / 110 Cd 部位-叶面暴露处理组 =δ 114 / 110 Cd 叶-叶面暴露处理组 +Δ 114 / 110 Cd 部位-叶 "

[0113] Formula (8);

[0114] (7) Calculate the contribution rates f2 and f1 of atmospheric deposition and original soil Cd to Cd in a certain part of the grain based on the Cd isotope mixing model.

[0115] Due to δ 114 / 110 Cd 部位 =f1×δ 114 / 110 Cd 部位 '+f2×δ 114 / 110 Cd 部位 "

[0116] 1 = f1 + f2

[0117] Formula (9);

[0118] The contribution rate of atmospheric deposition to Cd in a certain part of the grain can be calculated by combining formula (9) with the above formulas (4), (5) and (7) or formulas (4), (6) and (8).

[0119] In the formula,

[0120] S represents the contribution rate of atmospheric deposition particles to Cd in various parts of the grain, calculated using the mass balance method in a greenhouse experiment.

[0121] Δ 114 / 110 Cd 根-颗粒 The Cd isotope fractionation value represents the Cd isotope fractionation that occurs when particles of atmospheric deposition are absorbed by the roots of grains during greenhouse experiments.

[0122] Δ 114 / 110 Cd 部位-根 "This represents the Cd isotope fractionation value that occurs when Cd absorbed by the roots from atmospheric particles is transported from the roots to a certain part of the grain during greenhouse experiments."

[0123] Δ 114 / 110 Cd 叶-颗粒 The Cd isotope fractionation value represents the amount of particles that are absorbed by the leaves of grains during atmospheric deposition in a greenhouse experiment.

[0124] Δ 114 / 110 Cd 部位-叶 "This represents the Cd isotope fractionation value that occurs when Cd absorbed by leaves from atmospheric particles is transported from the leaves to a certain part of the grain during greenhouse experiments."

[0125] Cd 暴露处理组 Cd concentration in a specific part of the grain in the exposure treatment group representing the greenhouse experiment;

[0126] Cd 空白处理组 This represents the Cd concentration in a specific part of the grain in the blank treatment group of the greenhouse experiment;

[0127] Δ 114 / 110 Cd 部位-根 'Represents the Cd isotope fractionation value that occurs when Cd absorbed from the soil by the roots is transported from the roots to a certain part of the grain.'

[0128] δ 114 / 110 Cd 根-对照组 The Cd isotope composition of cereal roots represents that of the control group.

[0129] δ 114 / 110 Cd 部位-对照组 The Cd isotope composition of a certain part of the grain in the control group;

[0130] δ 114 / 110 Cd 部位-根部暴露处理组 'This represents the Cd isotopic composition of a certain part of the grain in the root exposure treatment group, which is contributed by the original Cd in the soil;'

[0131] δ 114 / 110 Cd 根-根部暴露处理组 'This represents the Cd isotopic composition of cereal roots in the root exposure treatment group, which is derived from the original Cd contribution from the soil.'

[0132] δ 114 / 110 Cd 部位-叶面暴露处理组 'Represents the Cd isotopic composition of a certain part of the grain in the foliar exposure treatment group, which is contributed by the original Cd in the soil;'

[0133] δ 114 / 110 Cd 根-叶面暴露处理组 'This represents the Cd isotopic composition of cereal roots from the original Cd in the soil in the foliar exposure treatment group;'

[0134] δ 114 / 110 Cd 根-根部暴露处理组 "This represents the Cd isotopic composition of cereal roots from atmospheric deposition contributed by Cd particles in the root exposure treatment group."

[0135] δ 114 / 110 Cd 叶-叶面暴露处理组 "Represents the Cd isotopic composition of cereal leaves from atmospheric deposition, contributed by Cd particles in the foliar exposure treatment group;

[0136] δ 114 / 110 Cd 部位-根部暴露处理组 "This represents the Cd isotopic composition of a portion of the grain from atmospheric deposition in the root exposure treatment group."

[0137] δ 114 / 110 Cd 部位-叶面暴露处理组 "This represents the Cd isotopic composition of a certain part of the grain from atmospheric deposition in the leaf exposure treatment group."

[0138] δ 114 / 110 Cd部位 Cd isotope composition of a specific part of a grain in different exposure groups;

[0139] δ 114 / 110 Cd 部位 'Represents the Cd isotopic composition of a certain part of the grain in different exposure groups, which is derived from the original Cd contribution from the soil;

[0140] δ 114 / 110 Cd 部位 "This represents the Cd isotopic composition of a portion of grain from atmospheric deposition, representing the Cd contribution from particles in different exposure groups."

[0141] δ 114 / 110 Cd 大气沉降 The Cd isotopic composition of particles deposited in the atmospheric deposition zone as measured in field experiments;

[0142] Δ 114 / 110 Cd 根-大气沉降 This represents the Cd isotope fractionation value that occurs when atmospheric particles are absorbed by the roots of grains during field experiments in atmospheric deposition zones.

[0143] f1 is the proportion of the original Cd from the soil that contributes to a certain part of the cereal crop;

[0144] f2 is the proportion of Cd from particles originating from atmospheric deposition that contributes to a specific part of cereal crops;

[0145] The parts mentioned include one of the following: roots, leaves, and rice grains.

[0146] In this invention, the non-atmospheric deposition zone is preferably an area more than 36 km away from the source of air pollution; the atmospheric deposition zone is preferably an area 0-2 km below the ground wind direction of the source of air pollution; the depth of the topsoil is preferably 0.1-20 cm, more preferably 5-15 cm, and even more preferably 10 cm; the particles in the atmospheric deposition zone are preferably particles from a pulse particle trap at the pollution source factory, and the particles are preferably ground to below 50 μm during use; the Cd concentration of the particles is preferably 1968.6 mg / kg; the control group and root exposure treatment group set in the field experiment are preferably both placed in the non-atmospheric deposition zone, and the foliar exposure treatment group is preferably placed in the atmospheric deposition zone; the root exposure treatment group set in the field experiment is preferably treated with polluted water collected by an atmospheric deposition collection device; the foliar exposure treatment group set in the field experiment is preferably treated with polluted water collected by an atmospheric deposition collection device. The soil surface is covered with a geomembrane to prevent atmospheric deposition from entering the soil; the atmospheric deposition collection device is preferably an atmospheric deposition collection bucket, preferably with a diameter of 30 cm and a height of 50 cm; the polluted water is preferably the liquid obtained by rinsing the atmospheric deposition collection bucket; the root exposure L treatment group and root exposure H treatment group set in the greenhouse experiment preferably have particles collected from the atmospheric deposition zone added to the soil before planting the grain; the leaf exposure L treatment group and leaf exposure H treatment group set in the greenhouse experiment preferably have particles collected from the atmospheric deposition zone applied to the front surface of the leaves when the grain grows to the jointing stage; the greenhouse experiment is preferably conducted in an environment with a room temperature of 25-35℃, more preferably in an environment with a room temperature of 26-32℃, and even more preferably in an environment with a room temperature of 28-30℃; the grain is preferably rice.

[0147] In this invention, in the greenhouse experiment, the root exposure L treatment group and the leaf exposure L treatment group preferably each contain 1-1.5g of particles, more preferably 1.2-1.4g of particles; the root exposure H treatment group and the leaf exposure H treatment group preferably each contain 2.5-3g of particles, more preferably 2.6-2.8g of particles; each treatment preferably has 2-3 replicates; 5-6kg of soil is added to each treatment group in both the field experiment and the greenhouse experiment; the mass of Cd added in the greenhouse experiment is preferably 4-10 times the original soil Cd mass, that is, when the Cd mass in the test soil is 0.5mg, the Cd mass in the test soil of the root exposure L treatment group and the root exposure H treatment group is adjusted to 2-5mg according to the Cd concentration of the particles, in order to simulate the excessive Cd load in the atmosphere and ignore the contribution of the original Cd in the test soil to rice.

[0148] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0149] Example 1

[0150] A method for calculating the contribution of atmospheric deposition to Cd enrichment in rice through different exposure pathways includes the following steps:

[0151] (1) Soil samples with a Cd concentration of 0.22 mg / kg at a depth of 10 cm from a non-atmospheric deposition area more than 36 km away from the source of air pollution were collected as test soil for the field experiment, and soil samples with a Cd concentration of <0.1 mg / kg were collected as test soil for the greenhouse experiment. Three atmospheric deposition collection buckets (with the same bottom area as the bottom area of ​​the test basin, the specifications of the atmospheric collection buckets being 30 cm in diameter and 50 cm in height; the specifications of the test basins being 30 cm in diameter and 20 cm in height) were set up in an area 0-2 km downwind from the source of air pollution to collect particles from the atmospheric deposition area as raw materials for the greenhouse experiment exposure treatment group. The weight of the collected particles was 50 g, and the obtained particles were ground to 50 μm for use. The Cd concentration of the ground particles was 1968.6 mg / kg.

[0152] (2) Field experiments and greenhouse experiments were set up separately. In the field experiment, a control group, a root exposure treatment group, and a foliar exposure treatment group were set up. The control group and the root exposure treatment group were placed in a non-atmospheric deposition area, while the foliar exposure treatment group was placed in an atmospheric deposition area. The root exposure treatment group was given polluted water collected by an atmospheric deposition collection device (the amount of water used was the same as the irrigation amount of the other treatment groups). A geomembrane was used to cover the soil surface of the foliar exposure treatment group to prevent atmospheric deposition from entering the soil. In the greenhouse experiment (the room temperature was 26°C), a blank treatment group, a root exposure L treatment group, a root exposure H treatment group, a foliar exposure L treatment group, and a foliar exposure H treatment group were set up. In the root exposure L treatment group, 1g of particles collected from the atmospheric deposition area was added to the soil before planting rice. In the root exposure H treatment group, 2.5g of particles collected from the atmospheric deposition area was added to the test soil before planting rice. Each treatment was set up with 3 replicate pots. Each pot contained 5kg of test soil. The amount of polluted water used was 200ml / time, twice a day, morning and evening.

[0153] (3) In each treatment group, rice of the variety Wuyou Huazhan was planted and grown to the three-leaf-one-heart stage. When the rice grew to the jointing stage, the particles collected from the atmospheric deposition zone were applied to the front surface of the rice leaves of the leaf exposure L treatment group and leaf exposure H treatment group in the greenhouse experiment at the dosages of 1g and 2.5g, respectively. After the rice matured, the Cd concentration and Cd isotope composition of rice grains, leaves and roots were measured.

[0154] The determination method is as follows: digestion is performed using HF-HClO4-HNO3, and after complete digestion, a double diluent is added ( 111 Cd-113 Cd was used to control the chemical separation and purification process of Cd, as well as the isotopic fractionation caused during Cd isotope testing by mass spectrometry. Then, AG-MP-1M anion exchange resin and single acid systems of different concentrations were used to elute the matrix element (Cd > 98%), achieving chemical separation and purification of Cd isotopes. Finally, numerical measurements were performed using multi-receiver inductively coupled plasma mass spectrometry (MC-ICP-MS), with a measurement error SD within 2 ± 0.06‰; the measurement results are as follows. Figure 1-5 As shown.

[0155] (4) Calculate the Cd contribution rate s of particles in the atmospheric deposition zone to different parts of rice in the greenhouse experiment according to formula (1). If s ≥ 85% compared to the blank treatment group, and the Cd isotope composition of different parts of rice obtained by different exposure methods is not significantly different, then the Cd isotope fractionation value under different exposure treatments is defined as the same, which is a constant value, that is, the Cd isotope fractionation value will not change with the change of particle dosage; and calculate the Cd isotope fractionation value of particles in the atmospheric deposition zone to different parts of rice through different exposure methods based on the Cd isotope composition value measured in the greenhouse experiment, that is, obtain Δ 114 / 110 Cd 根-颗粒 Δ 114 / 110 Cd 部位-根 ", Δ 114 / 110 Cd 叶-颗粒 Δ 114 / 110 Cd 部位-叶 ”;

[0156] The calculation of Cd isotope fractionation values ​​is based on Δ 114 / 110 Cd A-B =δ 114 / 110 Cd A -δ 114 / 110 Cd B Calculated;

[0157] S=((Cd 暴露处理组 -Cd 空白处理组 ) / Cd 暴露处理组 )×100% formula (1);

[0158] (5) Assuming that under the same rice variety, soil, and planting pattern, the Cd isotope fractionation value (ΔCd) from the soil to a certain part of the rice root is... 114 / 110 Cd 部位-根 If δ is constant, then the isotopic fractionation value passes through the root (δ) in the control group of the field experiment. 114 / 110 Cd 根-对照组 ) and any part (δ) 114 / 110 Cd 部位-对照组The Cd isotope composition of ) is used to calculate, thus obtaining formula (2): Δ 114 / 110 Cd 部位-根 '=δ 114 / 110 Cd 部位-对照组 -δ 114 / 110 Cd 根-对照组

[0159] =δ 114 / 110 Cd 部位-根部暴露处理组 '-δ 114 / 110 Cd 根-根部暴露处理组 '

[0160] =δ 114 / 110 Cd 部位-叶面暴露处理组 '-δ 114 / 110 Cd 根-叶面暴露处理组 '

[0161] Formula (2);

[0162] Since the rice roots grew in the same soil in the field experiments, the Cd isotopic composition contributed by the original Cd from the soil was the same.

[0163] δ 114 / 110 Cd 根-对照组 =δ 114 / 110 Cd 根-根部暴露处理组 '=δ 114 / 110 Cd 根-叶面暴露处理组 ';

[0164] Formula (3);

[0165] Substituting formula (3) into formula (2), we get:

[0166] δ 114 / 110 Cd 部位-根部暴露处理组 '=δ 114 / 110 Cd 部位-叶面暴露处理组 '

[0167] =Δ 114 / 110 Cd 部位-根 '+δ 114 / 110 Cd 根-对照组

[0168] Formula (4);

[0169] (6) Since all the Cd in the roots and leaves of rice in the greenhouse experiment came from the particles, the fractionation value of Cd absorbed by the roots and leaves of rice from the particles was defined under different exposure doses: Δ 114 / 110 Cd 根-颗粒 and Δ 114 / 110 Cd 叶-颗粒 And the fractionation value Δ during Cd transport between different parts 114 / 110 Cd 部位-根 "and Δ 114 / 110 Cd部位-叶 "Unchanged, proceed to the next calculation:"

[0170] Assuming that in field experiments, the absorption and translocation of atmospheric Cd particles by rice roots (or leaves) results in the same isotopic fractionation as in greenhouse experiments, then:

[0171] δ 114 / 110 Cd 根-根部暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-大气沉降

[0172] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 根-颗粒

[0173] Formula (5);

[0174] δ 114 / 110 Cd 叶-叶面暴露处理组 =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-大气沉降

[0175] =δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 叶-颗粒

[0176] Formula (6);

[0177] Similar to the principle of formula (4): In field experiments, the Cd isotopic composition of any part can be calculated from the Cd isotopic composition of the roots or leaves and the Cd isotopic fractionation values ​​within the rice plant.

[0178] δ 114 / 110 Cd 部位-根部暴露处理组 =δ 114 / 110 Cd 根-根部暴露处理组 +Δ 114 / 110 Cd 部位-根 "

[0179] Formula (7);

[0180] δ 114 / 110 Cd 部位-叶面暴露处理组 =δ 114 / 110 Cd 叶-叶面暴露处理组 +Δ 114 / 110 Cd 部位-叶 "

[0181] Formula (8);

[0182] (7) Calculate the contribution rates f2 and f1 of atmospheric deposition particles and original soil Cd to Cd in a certain part of rice based on the Cd isotope mixing model.

[0183] Due to δ 114 / 110 Cd 部位 =f1×δ 114 / 110 Cd 部位 '+f2×δ 114 / 110 Cd 部位 "

[0184] 1 = f1 + f2

[0185] Formula (9);

[0186] By combining formula (9) with the above formulas (4), (5) and (7) or formulas (4), (6) and (8), the contribution rate of atmospheric deposition particles to Cd in a certain part of rice can be calculated.

[0187] Experimental Example 1

[0188] Rice was planted according to the methods in steps (1)-(3) of the embodiment, and the Cd concentration and Cd isotope composition of rice grains, leaves and roots were measured. The results of the measured Cd concentration in different parts of the rice are shown in Table 1 and Table 2.

[0189] Table 1. Cd concentrations in different parts of rice plants during field experiments.

[0190]

[0191]

[0192] Table 2. Cd concentrations in different parts of rice plants during greenhouse experiments.

[0193]

[0194] S=((Cd 暴露处理组 -Cd 空白处理组 ) / Cd 暴露处理组 )×100% formula (1)

[0195] The contribution rate s of particles in the atmospheric deposition zone to Cd in various parts of rice in the greenhouse experiment was calculated according to formula (1). The results showed that s ≥ 85% compared with the blank treatment group. Moreover, the Cd isotope composition of various parts of rice obtained by different exposure methods was not significantly different. Therefore, it is defined that the Cd isotope fractionation value under different exposure treatments is the same and is a constant value. That is, the Cd isotope fractionation value will not change with the amount of particles used.

[0196] Meanwhile, based on the Cd isotope composition values ​​measured in the greenhouse experiment, the Cd isotope fractionation values ​​of different parts of rice plants caused by particles in the atmospheric deposition zone through different exposure pathways were calculated, specifically:

[0197] δ 114 / 110 Cd 颗粒 =-1.2‰±0.01,δ 114 / 110 Cd 根 = -1.02‰ ± 0.02,

[0198] δ 114 / 110 Cd 叶 =-1.1‰±0.01,δ 114 / 110 Cd 稻米 = -0.7‰ ± 0.01,

[0199] δ 114 / 110 Cd 颗粒 The Cd isotopic composition of particles collected from atmospheric deposition zones and measured during greenhouse experiments;

[0200] Then according to Δ 114 / 110 Cd A-B =δ 114 / 110 Cd A -δ 114 / 110 Cd B We can obtain:

[0201] Δ 114 / 110 Cd 根-颗粒 =δ 114 / 110 Cd 根 -δ 114 / 110 Cd 颗粒 =0.18‰±0.03;

[0202] Δ 114 / 110 Cd 叶-颗粒 =δ 114 / 110 Cd 叶 -δ 114 / 110 Cd 颗粒 =0.1‰±0.02;

[0203] Δ 114 / 110 Cd 稻米-根 =δ 114 / 110 Cd 稻米 -δ 114 / 110 Cd 根 =0.32‰±0.03;

[0204] Δ 114 / 110 Cd 稻米-叶 =δ 114 / 110 Cd 稻米 -δ 114 / 110 Cd 叶 =0.38‰±0.02;

[0205] Isotopic composition of particles in atmospheric deposition zones measured in field experiments:

[0206] δ 114 / 110 Cd 大气沉降 = -0.68‰ ± 0.03,

[0207] The isotopic composition of different parts of rice measured in the control group was as follows:

[0208] δ 114 / 110 Cd 根 = -0.32‰ ± 0.03;

[0209] δ 114 / 110 Cd 叶 = -0.29‰ ± 0.02;

[0210] δ 114 / 110 Cd 稻米 =0.04‰±0.02;

[0211] The isotopic composition of different parts in the root exposure treatment group is as follows:

[0212] δ 114 / 110 Cd 根 = -0.42‰ ± 0.02;

[0213] δ 114 / 110 Cd 叶 = -0.36‰ ± 0.03;

[0214] δ 114 / 110 Cd 稻米 = -0.03‰ ± 0.02;

[0215] The isotopic composition of different parts of the leaves in the leaf exposure treatment group is as follows:

[0216] δ 114 / 110 Cd 根 = -0.32‰ ± 0.03;

[0217] δ 114 / 110 Cd 叶 = -0.46‰ ± 0.02;

[0218] δ 114 / 110 Cd 稻米 = -0.13‰ ± 0.02.

[0219] Meanwhile, based on the Cd isotope composition values ​​measured in the control group during the field experiment, the Cd isotope fractionation values ​​caused by the translocation of original Cd in the soil from the roots to the leaves of rice were calculated, specifically:

[0220] Δ 114 / 110Cd 叶-根 '=δ 114 / 110 Cd 叶 -δ 114 / 110 Cd 根 =0.03‰±0.02;

[0221] Calculate f1 and f2 according to equation (9), as follows:

[0222] (Note: When calculating f1 and f2, the original values ​​measured above are all selected from the values ​​before “±”, and the values ​​after “±” are discarded. If it is necessary to calculate the values ​​after “±”, the formulas (3), (4), (5) and (6) in the “METHODS” section of the book “JONATHAN W.MOORE, BRICEX.SEMMENS.Incorporating uncertainty and prior information into stable isotopemixing models[J].Ecology Letters,2008,11(5):470-480.DOI:10.1111 / j.1461-0248.2008.01163.x.” can be used for calculation.)

[0223] 1.1 When rice roots are contaminated through root exposure, calculate the contribution rate f2 of atmospheric deposition to rice roots:

[0224] δ 114 / 110 Cd 根 '=δ 114 / 110 Cd 根-对照组 = -0.32‰

[0225] δ 114 / 110 Cd 根 =Δ 114 / 110 Cd 根-颗粒 +δ 114 / 110 Cd 大气沉降 = -0.50‰

[0226] δ 114 / 110 Cd 根 =f1×δ 114 / 110 Cd 根 '+f2×δ 114 / 110 Cd 根 "

[0227] 1 = f1 + f2

[0228] The calculations yielded: f2 = 56%, f1 = 44%.

[0229] 1.2 When rice roots are contaminated through root exposure, calculate the contribution rate f2 of atmospheric deposition to rice grains:

[0230] δ 114 / 110 Cd 稻米 '=Δ 114 / 110 Cd 稻米-根 '+δ 114 / 110 Cd 根-对照组

[0231] =δ 114 / 110 Cd 稻米-对照组 =0.04‰;

[0232] δ 114 / 110 Cd 稻米 =Δ 114 / 110 Cd 根-颗粒 +δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 稻米-根 = -0.18‰

[0233] δ 114 / 110 Cd 稻米 =f1×δ 114 / 110 Cd 稻米 '+f2×δ 114 / 110 Cd 稻米 "

[0234] 1 = f1 + f2

[0235] Calculations yielded: f2 = 32%, f1 = 68%;

[0236] 1.3 When rice leaves are contaminated through foliar exposure, calculate the contribution rate f2 of atmospheric deposition to rice leaves:

[0237] δ 114 / 110 Cd 叶 '=Δ 114 / 110 Cd 叶 -root'+δ 114 / 110 Cd 根-对照组 = -0.29‰

[0238] δ 114 / 110 Cd 叶 =Δ 114 / 110 Cd 叶-颗粒 +δ 114 / 110 Cd 大气沉降 = -0.58‰

[0239] δ 114 / 110 Cd 叶 =f1×δ 114 / 110 Cd 叶 '+f2×δ 114 / 110 Cd 叶 "

[0240] 1 = f1 + f2

[0241] The calculations yielded: f2 = 59%, f1 = 41%;

[0242] 1.4 When rice leaves are contaminated through foliar exposure, calculate the contribution rate f2 of atmospheric deposition to rice grains:

[0243] δ 114 / 110 Cd 稻米 '=Δ 114 / 110 Cd 稻米-根 '+δ 114 / 110 Cd 根-对照组 =0.04‰

[0244] δ 114 / 110 Cd 稻米 =Δ 114 / 110 Cd 叶-颗粒 +δ 114 / 110 Cd 大气沉降 +Δ 114 / 110 Cd 稻米 - 叶 = -0.20‰

[0245] δ 114 / 110 Cd 稻米 =f1×δ 114 / 110 Cd 稻米 '+f2×δ 114 / 110 Cd 稻米 "

[0246] 1 = f1 + f2

[0247] The calculations yielded: f2 = 71%, f1 = 29%.

[0248] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for calculating the contribution rate of atmospheric deposition to Cd enrichment in grains through different exposure pathways, characterized in that, Includes the following steps: (1) Collect surface soil from non-atmospheric deposition areas as test soil, and collect particles from atmospheric deposition areas as raw materials for exposure treatment; (2) Field experiments and greenhouse experiments were set up respectively. In the field experiment, a control group, a root exposure treatment group and a leaf exposure treatment group were set up. In the greenhouse experiment, a blank treatment group and an exposure treatment group were set up. The exposure treatment group included root exposure L treatment group, root exposure H treatment group, leaf exposure L treatment group and leaf exposure H treatment group. In step (2), the control group and root exposure treatment group in the field experiment were placed in a non-atmospheric deposition area, while the leaf exposure treatment group was placed in an atmospheric deposition area. The root exposure treatment group in the field experiment was given polluted water collected by an atmospheric deposition collection device. The soil surface of the leaf exposure treatment group in the field experiment was covered with a geomembrane to prevent atmospheric deposition from entering the soil. In step (2), the root exposure L treatment group and the root exposure H treatment group set up in the greenhouse experiment added particles collected from the atmospheric deposition zone to the soil before planting the grain. In the leaf exposure L treatment group and the leaf exposure H treatment group set up in the greenhouse experiment, the particles collected from the atmospheric deposition zone were applied to the front surface of the leaves when the grain grew to the jointing stage. The greenhouse experiment was carried out in an environment with a room temperature of 25~35℃. 1-1.5 g of granules were added to both the root exposure L treatment group and the leaf exposure L treatment group; Both the root exposure H treatment group and the leaf exposure H treatment group had 2.5~3g of granules added; (3) Grains were planted in each treatment group. After the grains matured, the Cd concentration and Cd isotope composition of each part of the grains were measured. (4) Calculate the Cd contribution rate S of the particles in the atmospheric deposition zone to different parts of the grain in the greenhouse experiment according to the formula (1). If s ≥ 85% compared with the blank treatment group, and the Cd isotope composition of different parts of the grain obtained by different exposure methods is not significantly different, then the Cd isotope fractionation value under different exposure treatments is defined as the same, which is a constant value, that is, the Cd isotope fractionation value will not change with the change of particle dosage; and calculate the Cd isotope fractionation value of the particles in the atmospheric deposition zone to different parts of the grain through different exposure methods according to the Cd isotope composition value measured in the greenhouse experiment, that is, obtain Δ 114 / 110 Cd 根-颗粒 Δ 114 / 110 Cd 部位-根 ", Δ 114 / 110 Cd 叶-颗粒 Δ 114 / 110 Cd 部位-叶 ”; The calculation of Cd isotope fractionation values ​​is based on Δ 114 / 110 Cd A-B =δ 114 / 110 Cd A -δ 114 / 110 Cd B Calculated; S = ((Cd 暴露处理组 -Cd 空白处理组 ) / Cd 暴露处理组 ) × 100% Formula (1); (5) Assuming that under the same grain variety, soil and planting pattern, the Cd isotope fractionation value (ΔCd) from the soil to a certain part of the grain root is different. 114 / 110 Cd 部位-根 If δ is constant, then the isotopic fractionation value is obtained by combining the Cd isotopes from the root and any location in the control group of the field experiment. 114 / 110 Cd 根-对照组 δ 114 / 110 Cd 部位-对照组 To calculate, we get formula (2): D 114 / 110 CD 部位-根 '=d 114 / 110 CD 部位-对照组 -d 114 / 110 CD 根-对照组 =d 114 / 110 CD 部位-根部暴露处理组 '-d 114 / 110 CD 根-根部暴露处理组 ' =d 114 / 110 CD 部位-叶面暴露处理组 '-d 114 / 110 CD 根-叶面暴露处理组 ' Formula (2); Since the grain roots grew in the same soil during the field experiment, the Cd isotopic composition contributed by the Cd from the original Cd in the soil was the same. d 114 / 110 CD 根-对照组 =d 114 / 110 CD 根-根部暴露处理组 '=d 114 / 110 CD 根-叶面暴露处理组 '; Formula (3); Substituting formula (3) into formula (2), we get: d 114 / 110 CD 部位-根部暴露处理组 '=d 114 / 110 CD 部位-叶面暴露处理组 ' =D 114 / 110 CD 部位-根 '+d 114 / 110 CD 根-对照组 Formula (4); (6) Since all the Cd in the roots and leaves of the grain in the greenhouse experiment came from the grain, the fractionation value of Cd absorbed by the roots and leaves of the grain from the grain is defined as follows: Δ 114 / 110 Cd 根-颗粒 and Δ 114 / 110 Cd 叶-颗粒 And the fractionation value Δ during Cd transport between different parts 114 / 110 Cd 部位-根 "and Δ 114 / 110 Cd 部位-叶 "Unchanged, proceed to the next calculation:" Since the isotopic fractionation value of Cd has been determined in part of equation (1) to be constant and does not change with the amount of particles used, it is assumed that in the field experiment, the absorption and translocation of atmospheric Cd by the roots or leaves of the grain caused by atmospheric deposition is the same as that caused by the absorption and translocation of particle Cd by the roots or leaves of the grain in the greenhouse experiment. Therefore: d 114 / 110 CD 根-根部暴露处理组 ”=d 114 / 110 CD 大气沉降 +D 114 / 110 CD 根-大气沉降 =d 114 / 110 CD 大气沉降 +D 114 / 110 CD 根-颗粒 Formula (5); d 114 / 110 CD 叶-叶面暴露处理组 ”=d 114 / 110 CD 大气沉降 +D 114 / 110 CD 叶-大气沉降 =d 114 / 110 CD 大气沉降 +D 114 / 110 CD 叶-颗粒 Formula (6); Similar to the principle of formula (4): In field experiments, the Cd isotopic composition of any part can be calculated from the Cd isotopic composition of the root or leaf and the Cd isotopic fractionation value within the grain: d 114 / 110 CD 部位-根部暴露处理组 ”=d 114 / 110 CD 根-根部暴露处理组 ”+D 114 / 110 CD 部位-根 " Formula (7); d 114 / 110 CD 部位-叶面暴露处理组 ”=d 114 / 110 CD 叶-叶面暴露处理组 ”+D 114 / 110 CD 部位-叶 " Formula (8); (7) Calculate the contribution rates f2 and f1 of atmospheric deposition and original soil Cd to Cd in a certain part of the grain based on the Cd isotope mixing model. Yuyu δ 114 / 110 CD 部位 = f1×δ 114 / 110 CD 部位 ' + f2×δ 114 / 110 CD 部位 '' 1 = f1 + f2 Formula (9); The contribution rate of atmospheric deposition to Cd in a certain part of the grain can be calculated by combining formula (9) with the above formulas (4), (5) and (7) or formulas (4), (6) and (8). In the formula, S represents the contribution rate of atmospheric deposition particles to Cd in various parts of the grain, calculated using the mass balance method in a greenhouse experiment. Δ 114 / 110 Cd 根-颗粒 The Cd isotope fractionation value represents the Cd isotope fractionation that occurs when particles of atmospheric deposition are absorbed by the roots of grains during greenhouse experiments. Δ 114 / 110 Cd 部位-根 "This represents the Cd isotope fractionation value that occurs when Cd absorbed by the roots from atmospheric particles is transported from the roots to a certain part of the grain during greenhouse experiments." Δ 114 / 110 Cd 叶-颗粒 The Cd isotope fractionation value represents the amount of particles that are absorbed by the leaves of grains during atmospheric deposition in a greenhouse experiment. Δ 114 / 110 Cd 部位-叶 "This represents the Cd isotope fractionation value that occurs when Cd absorbed by leaves from atmospheric particles is transported from the leaves to a certain part of the grain during greenhouse experiments." Cd 暴露处理组 Cd concentration in a specific part of the grain in the exposure treatment group representing the greenhouse experiment; Cd 空白处理组 This represents the Cd concentration in a specific part of the grain in the blank treatment group of the greenhouse experiment; Δ 114 / 110 Cd 部位-根 'Represents the Cd isotope fractionation value that occurs when Cd absorbed from the soil by the roots is transported from the roots to a certain part of the grain.' δ 114 / 110 Cd 根-对照组 The Cd isotope composition of cereal roots represents that of the control group. δ 114 / 110 Cd 部位-对照组 The Cd isotope composition of a certain part of the grain in the control group; δ 114 / 110 Cd 部位-根部暴露处理组 'This represents the Cd isotopic composition of a certain part of the grain in the root exposure treatment group, which is contributed by the original Cd in the soil;' δ 114 / 110 Cd 根-根部暴露处理组 'This represents the Cd isotopic composition of cereal roots in the root exposure treatment group, which is derived from the original Cd contribution from the soil.' δ 114 / 110 Cd 部位-叶面暴露处理组 'Represents the Cd isotopic composition of a certain part of the grain in the foliar exposure treatment group, which is contributed by the original Cd in the soil;' δ 114 / 110 Cd 根-叶面暴露处理组 'This represents the Cd isotopic composition of cereal roots from the original Cd in the soil in the foliar exposure treatment group;' δ 114 / 110 Cd 根-根部暴露处理组 "This represents the Cd isotopic composition of cereal roots from atmospheric deposition contributed by Cd particles in the root exposure treatment group." δ 114 / 110 Cd 叶-叶面暴露处理组 "Represents the Cd isotopic composition of cereal leaves from atmospheric deposition, contributed by Cd particles in the foliar exposure treatment group; δ 114 / 110 Cd 部位-根部暴露处理组 "This represents the Cd isotopic composition of a portion of the grain from atmospheric deposition in the root exposure treatment group." δ 114 / 110 Cd 部位-叶面暴露处理组 "This represents the Cd isotopic composition of a certain part of the grain from atmospheric deposition in the leaf exposure treatment group." δ 114 / 110 Cd 部位 Cd isotope composition of a specific part of a grain in different exposure groups; δ 114 / 110 Cd 部位 'Represents the Cd isotopic composition of a certain part of the grain from the original Cd contribution from the soil in different exposure groups; δ 114 / 110 Cd 部位 '' represents the Cd isotopic composition of a portion of grain from atmospheric deposition in different exposure groups; δ 114 / 110 Cd 大气沉降 The Cd isotopic composition of particles deposited in the atmospheric deposition zone as measured in field experiments; Δ 114 / 110 Cd 根-大气沉降 This represents the Cd isotope fractionation value that occurs when atmospheric particles are absorbed by the roots of grains during field experiments in atmospheric deposition zones. f1 is the proportion of the original Cd from the soil that contributes to a certain part of the cereal crop; f2 is the proportion of Cd from particles originating from atmospheric deposition that contributes to a specific part of cereal crops; The part mentioned includes one of the following: root, leaf, and rice grain.

2. The method according to claim 1, characterized in that, In step (1), the non-atmospheric deposition zone is the area more than 36 km away from the source of air pollution; the atmospheric deposition zone is the area 0-2 km away from the source of air pollution in the wind direction; the depth of the surface soil is 0.1-20 cm; the particles in the atmospheric deposition zone are the particles in the pulse particle trap of the pollution source factory, and the particles are ground to below 50 μm during use.

3. The method according to claim 1, characterized in that, The atmospheric deposition collection device is an atmospheric deposition collection tank, and the polluted water is the liquid obtained by cleaning the atmospheric deposition collection tank.

4. The method according to claim 1, characterized in that, The grain in question is rice.

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