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CN-121978226-A - Multi-monomer stable isotope source analysis method for chlorinated hydrocarbon in groundwater

CN121978226ACN 121978226 ACN121978226 ACN 121978226ACN-121978226-A

Abstract

The application provides a multi-monomer stable isotope source analysis method of chlorinated hydrocarbon in groundwater, which relates to the field of groundwater pollution tracing, and comprises the steps of constructing a three-dimensional isotope characteristic matrix according to a determined target pollutant and a corresponding three-monomer stable isotope system of carbon, chlorine and hydrogen; arranging sampling points in a polluted site, collecting an underground water sample, preprocessing, performing isotope measurement on the sample to obtain isotope data, constructing a fractionation model of a hydrocarbon isotope, inputting the isotope data into the fractionation model for correction, performing cluster analysis in a three-dimensional isotope space by utilizing the corrected isotope data and combining a three-dimensional isotope characteristic matrix, identifying different pollution sources, and performing result verification by combining chemical fingerprint characteristics and an underground water flow field model. The technical scheme of the application weakens the dependence on the traditional concentration discrimination and realizes the fine discrimination and contribution quantification among different pollution sources.

Inventors

  • LIU HUI
  • FU ZHIGAO
  • BIAN HAONAN
  • DENG HUILING

Assignees

  • 中国地质大学（武汉）

Dates

Publication Date
20260505
Application Date
20251203

Claims (8)

  1. 1. A method for analyzing a multi-monomer stable isotope source of chlorinated hydrocarbon in groundwater is characterized by comprising the following steps: s1, determining a target pollutant and a corresponding carbon, chlorine and hydrogen monomer stable isotope system according to the chlorinated hydrocarbon composition of a pollution site, and constructing a three-dimensional isotope characteristic matrix; S2, arranging sampling points in a polluted site, collecting an underground water sample and preprocessing; s3, performing isotope measurement on the pretreated sample to obtain isotope data; S4, constructing a fractionation model of the hydrocarbon and hydrogen isotopes based on the reaction path of the chlorinated hydrocarbon in the underground water; s5, inputting isotope data into a fractionation model for correction; And S6, performing cluster analysis in a three-dimensional isotope space by utilizing the corrected isotope data and combining a three-dimensional isotope characteristic matrix, identifying different pollution sources, and performing result verification by combining chemical fingerprint characteristics and a groundwater flow field model.
  2. 2. The method for analyzing a stable isotope source of a multiple monomer of chlorinated hydrocarbon in groundwater according to claim 1, wherein step S2 comprises: The number of sampling points is not less than 10, and the pollution feather core area, the diffusion area and the background area are covered; Pretreatment includes enrichment of chlorinated hydrocarbons using solid phase microextraction or purge-and-trap methods, and preparation of purified samples suitable for carbon, hydrogen, chlorine isotope determination.
  3. 3. The method for analyzing a stable isotope source of a multiple monomer of chlorinated hydrocarbon in groundwater according to claim 1, wherein step S3 comprises: Isotope determination was performed on the samples using the following instruments and conditions: Delta 13 C is measured by using a gas chromatograph-combustion-isotope ratio mass spectrometer, and the temperature of a combustion furnace is 1000 ℃; Delta 2 H was determined using a gas chromatograph-high temperature shift-isotope ratio mass spectrometer; delta 37 Cl was measured using a gas chromatograph-quadrupole mass spectrometer; in the measurement of delta 37 Cl, standard average ocean chlorine is inserted as a standard substance, and three repeated measurement is carried out, and the relative standard deviation is controlled within 1.5%.
  4. 4. The method for analyzing a stable isotope source of a multiple monomer of chlorinated hydrocarbon in groundwater according to claim 1, wherein step S4 comprises: The fractionation model comprises a Rayleigh fractionation model and a secondary kinetic isotope fractionation model; the fractionation model includes the equation of ray Li Fenliu for describing the fractionation of chlorine isotopes during the bioreductive dechlorination: Wherein, the In order to achieve a transient isotope ratio, For the initial isotope ratio value, In order to obtain the fraction of the remaining reactants, Is the fractional distillation coefficient.
  5. 5. The method for analyzing a stable isotope source of a multiple monomer of chlorinated hydrocarbon in groundwater according to claim 1, wherein step S6 comprises: isotope data is delta 13 C、δ 37 Cl、δ 2 H data; The combination of chemical fingerprint features means that the concentration distribution of chlorinated hydrocarbon and its degradation products is obtained through non-target combination technology, and consistency test is carried out with isotope clustering result.
  6. 6. The method for resolving a multi-monomer stable isotope of chlorinated hydrocarbon in groundwater as defined in claim 1, wherein step S6 further comprises: Combining with the groundwater flow field model means that the flow direction of groundwater is simulated by using MODIOWW or ArcGIS, isotope data features are projected along the flow direction, and whether the evolution trend of a source end-a migration end is met or not is judged.
  7. 7. An electronic device comprising a processor, a memory, a user interface, and a network interface, the memory for storing instructions, the user interface and the network interface for communicating to other devices, the processor for executing the instructions stored in the memory to cause the electronic device to perform the method of multi-monomer stable isotope source resolution of chlorinated hydrocarbons in groundwater as claimed in any one of claims 1 to 6.
  8. 8. A computer readable storage medium storing instructions which, when executed by a computer, perform the method of multi-monomer stable isotope source resolution of chlorinated hydrocarbons in groundwater according to any one of claims 1-6.

Description

Multi-monomer stable isotope source analysis method for chlorinated hydrocarbon in groundwater Technical Field The application relates to the technical field of underground water pollution tracing and environmental isotope geochemistry, in particular to a method for analyzing a multi-monomer stable isotope source of chlorinated hydrocarbon in underground water. Background Chlorinated hydrocarbons (such as trichloroethylene TCE, tetrachloroethylene PCE, dichloroethylene DCE, vinyl chloride VC, etc.) are widely used for metal cleaning, electronic manufacturing and chemical production, and are the most common and difficult to treat volatile organic contaminants in groundwater. The source is complex, and the pollution often presents multi-point, multi-period and multi-process superposition characteristics. Traditional pollution tracing technologies face the following limitations: 1. The chemical concentration method depends on the concentration distribution of pollutants, is difficult to distinguish similar chlorinated hydrocarbons from different sources, is easily interfered by hydrological geochemical processes such as groundwater flow, adsorption-desorption and the like, and has low accuracy; 2. monoisotopic traceability can identify part of types of pollution sources, but cannot quantify the contribution proportion of multiple pollution sources; 3. The hydrogeologic simulation method is that the pollution diffusion path is reversely pushed only through the water flow model, the characteristic difference of the pollutants is ignored, and the superposition scene of multiple pollution sources is difficult to deal with; 4. The existing multi-element method lacks a unified technical system, and chemical characteristics, isotope data and hydrological parameters cannot form a system which can be directly used for source analysis. Therefore, a technical system with "monomer stable isotope" as a core is needed to realize higher precision, stronger distinction and quantifiable pollution source identification through isotope fingerprint change of chlorinated hydrocarbon in the reaction and migration processes. Disclosure of Invention The invention aims to solve the problem that the existing chlorinated hydrocarbon traceability technology cannot realize high-precision and quantifiable pollution source identification and contribution analysis under the remarkable conditions of multi-source superposition and degradation, and provides a method for analyzing a stable isotope source of a polynary monomer of chlorinated hydrocarbon in groundwater. The above object of the present application is achieved by the following technical solutions: s1, determining a target pollutant and a corresponding carbon, chlorine and hydrogen monomer stable isotope system according to the chlorinated hydrocarbon composition of a pollution site, and constructing a three-dimensional isotope characteristic matrix; S2, arranging sampling points in a polluted site, collecting an underground water sample and preprocessing; s3, performing isotope measurement on the pretreated sample to obtain isotope data; S4, constructing a fractionation model of the hydrocarbon and hydrogen isotopes based on the reaction path of the chlorinated hydrocarbon in the underground water; s5, inputting isotope data into a fractionation model for correction; And S6, performing cluster analysis in a three-dimensional isotope space by utilizing the corrected isotope data and combining a three-dimensional isotope characteristic matrix, identifying different pollution sources, and performing result verification by combining chemical fingerprint characteristics and a groundwater flow field model. Optionally, step S2 includes: The number of sampling points is not less than 10, and the pollution feather core area, the diffusion area and the background area are covered; Pretreatment includes enrichment of chlorinated hydrocarbons using solid phase microextraction or purge-and-trap methods, and preparation of purified samples suitable for carbon, hydrogen, chlorine isotope determination. Optionally, step S3 includes: Isotope determination was performed on the samples using the following instruments and conditions: Delta 13 C is measured by using a gas chromatograph-combustion-isotope ratio mass spectrometer, and the temperature of a combustion furnace is 1000 ℃; Delta 2 H was determined using a gas chromatograph-high temperature shift-isotope ratio mass spectrometer; delta 37 Cl was measured using a gas chromatograph-quadrupole mass spectrometer; in the measurement of delta 37 Cl, standard average ocean chlorine is inserted as a standard substance, and three repeated measurement is carried out, and the relative standard deviation is controlled within 1.5%. Optionally, step S4 includes: The fractionation model comprises a Rayleigh fractionation model and a secondary kinetic isotope fractionation model; the fractionation model includes the equation of ray Li Fenliu for describing the