Water body pollution tracing method

Abstract

The invention discloses a water body pollution tracing method. The method comprises the following steps: collecting water samples of a plurality of water bodies in a target area and a plurality of pollution source samples around the water bodies; carrying out pretreatment on the water sample and the pollution source sample; adjusting the volumes of the water sample and the pollution source sample to enable the dissolved organic carbon content of each sample to be consistent, extracting organic matters in each sample, and preparing a to-be-detected solution; collecting high-resolution mass spectrum data of the to-be-detected liquid and performing pretreatment; carrying out peak extraction and peak alignment on the high-resolution mass spectrum data, then calculating the similarity between the water body sample and each pollution source sample, and quantitatively calculating the contribution rate of each pollution source to the water body; judging primary and secondary pollution sources of the water body; and identifying the characteristic mass spectrum peaks of the pollution sources, and determining the positions of the main pollution sources according to the spatial distribution rule of the characteristic mass spectrum peaks in the water environment of the target area. According to the method, the pollution characteristics of the target area are comprehensively reflected by using the overall organic matter mass spectrum information, so that the water pollution traceability is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental monitoring, and in particular to a method for tracing the source of water pollution. Background Art

[0002] Emissions from multiple pollution sources will introduce a large number of pollutants, especially organic pollutants, into the water environment. Water pollution caused by some organic pollutants is difficult to control, and the cost of end-of-pipe control is high. Therefore, it is necessary to accurately identify the sources of water pollution and prevent water pollution from the source, so as to eliminate the phenomenon of illegal discharge and leakage, reduce the discharge of pollutants, effectively support water environment supervision and protect the water environment.

[0003] Existing technologies mainly trace the source of water pollution based on traditional water quality indicators (such as total nitrogen, ammonia nitrogen, heavy metals, fluorescent dissolved organic matter, etc.), which can identify some common pollution sources; the tracing method based on three-dimensional fluorescence mainly uses fluorescent dissolved organic matter to monitor the source of water pollution in a timely manner; the tracing method based on liquid chromatography tandem mass spectrometry collects some organic matter information and can calculate the contribution rate of the pollution source.

[0004] For example, the Chinese patent document with publication number CN115713448A proposes a rapid tracing method for conventional factors of water pollution in a watershed based on catchment units for non-sudden water pollution factors such as chemical oxygen demand, total phosphorus, and ammonia nitrogen in daily water quality monitoring. It follows the logic of "fixed section - fixed area - fixed type - fixed list" and increases the frequency of tracing the cumulative water pollution indicators to daily tracing, and reduces the tracing accuracy from the watershed scale to the river section scale, township scale, pollution source type scale and point scale, providing support for daily water environment management decisions.

[0005] A Chinese patent document with publication number CN115950864A discloses a water pollution source tracing detection method based on three-dimensional fluorescence spectroscopy, which includes the following steps: obtaining a contaminated water sample from a water quality detection area; pre-processing the fluorescent area of ​​the contaminated water sample; generalizing the substance molecules in the contaminated water sample into an energy level model and analyzing the three-dimensional fluorescence spectrum, and finally determining the relationship between two characteristic parameters in the contaminated water sample; establishing a water area spatial distribution model and creating a source tracing detection semantic network; matching the collected contaminated water sample data with the water area spatial distribution model to complete the source tracing operation.

[0006] However, these technologies are mainly based on general water quality data or some organic matter and cannot represent all organic matter. They may miss some key information on organic pollutants and therefore cannot fully reflect the sources of organic pollutants or accurately identify the main sources of pollution in the water environment. Summary of the invention

[0007] The present invention provides a method for tracing the source of water pollution, which can comprehensively reflect the sources of organic pollutants and accurately identify the main pollution sources of the water environment.

[0008] The technical solution of the present invention is as follows:

[0009] A method for tracing the source of water pollution comprises the following steps:

[0010] (1) Collecting water samples from multiple water bodies in the target area and collecting multiple pollution source samples around the water bodies in the target area; and pre-treating the collected multiple water body water samples and multiple pollution source samples;

[0011] (2) Detecting the dissolved organic carbon concentration of the sample, adjusting the volume of the water sample and the pollution source sample to make the dissolved organic carbon content of each sample consistent, extracting the organic matter in each sample, and preparing the test solution;

[0012] (3) collecting high-resolution mass spectrometry data of each sample test solution and performing preprocessing;

[0013] (4) Peak extraction and peak alignment are performed on the high-resolution mass spectrometry data of each sample after pretreatment, and then the similarity between the water sample and the samples of each pollution source is calculated to quantitatively calculate the contribution rate of each pollution source to the water body;

[0014] (5) Conduct significance tests, compare the contribution rates of various pollution sources, and determine the main and secondary pollution sources of water bodies;

[0015] (6) Identify the characteristic mass spectrum peaks of the main pollution sources and determine the location of the main pollution sources based on the spatial distribution patterns of the characteristic mass spectrum peaks in the target area.

[0016] In step (1), pre-treating the sample includes filtering the sample through a membrane.

[0017] In step (2), the organic matter in each sample is extracted to prepare a soluble organic matter test solution of each sample, including: connecting a solid phase extraction column to a solid phase extractor, adding 3 mL of methanol to activate the solid phase extraction column, using a vacuum pump to provide power to allow the sample to flow through the solid phase extraction column, drying with a nitrogen blower, and then adding 5 mL of pure methanol for elution, and the prepared eluate is stored at low temperature.

[0018] In step (3), a Fourier transform ion cyclotron resonance mass spectrometer with a resolution greater than 1000000 is used to collect high-resolution mass spectrometric data of each sample, using a negative electrospray ionization mode (ESI-) with a mass-to-charge ratio range (m / z) of 100-1000.

[0019] In step (3), the high-resolution mass spectrometry data is preprocessed including: using a blank sample as a control to remove interference from miscellaneous peaks; removing mass spectrometry peaks with a sample detection rate of less than 10%; and retaining the mass-to-charge ratio, peak height and peak area data of mass spectrometry peaks with a signal-to-noise ratio (S / N) greater than 6.0 after internal standard correction.

[0020] In step (4), the similarity between the water sample and the samples of each pollution source is calculated, and the contribution rate of each pollution source to the water body is quantitatively calculated, including:

[0021] The similarity algorithm is used to calculate the similarity between the kth (k=1, 2, 3, 4…n) water body and the jth (j=1, 2…m) pollution source. The similarity algorithm is:

[0022]

[0023] Among them, W i is the intensity of the ith mass spectrum peak of water, S i is the intensity of the i-th mass spectrum peak of the pollution source;

[0024] The similarity between the kth water body and the jth pollution source is taken as the contribution rate of the jth pollution source to the kth water body.

[0025] In step (5), a significance test is used to compare the contribution rate of each pollution source to the water body.

[0026] In step (6), the cluster analysis method is used to obtain the spatial clustering results of the characteristic mass spectrum peaks of the main pollution sources in the target area, and the location of the main pollution sources is determined by determining the water samples affected by the main pollution sources.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] In response to the problem of lack of organic matter data or small data volume in the prior art, the present invention uses high-resolution mass spectrometry to detect all organic matter in the sample. Based on the detection results of the overall organic matter, a suitable algorithm is used to compare the pollution characteristics of the sample, which can identify the main sources of water pollution and improve the accuracy of water pollution tracing.

[0029] The present invention only uses high-resolution mass spectrometry, and the detection method is simpler; high-resolution mass spectrometry can scan and detect the overall organic compounds in the environment, with higher mass spectrum resolution, larger amount of mass spectrum data collected, and more information on the types of organic matter included; the pollution source calculation method uses the overall mass spectrum data information of the sample, which can more comprehensively reflect the pollution characteristics of the water environment in the area, and the calculation method is more efficient; based on a larger amount of organic matter data, a more advanced algorithm is used to identify the main pollution sources, making water pollution tracing more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1This is the mass spectrum of sample 1. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0032] The water pollution source tracing method of the present invention comprises the following steps:

[0033] (1) Collect samples.

[0034] Stainless steel samplers are used to collect surface water samples from multiple water bodies (such as lakes) in the study area, to investigate potential sources of pollution that affect the water environment in the area, to collect samples from multiple pollution sources, and to store the samples at low temperatures.

[0035] (2) Pre-treat the samples.

[0036] The large particles in the sample were removed by filtration with a membrane filter, and the dissolved organic carbon concentrations of the sample and ultrapure water were detected using a total organic carbon analyzer. After deducting the ultrapure water blank, the corrected dissolved organic carbon concentration was obtained.

[0037] Connect the solid phase extraction column to the solid phase extraction instrument, add 3 mL of methanol to activate the solid phase extraction column, use a vacuum pump to provide power, so that the sample with uniform dissolved organic carbon content and blank Milli-Q water flow through the solid phase extraction column, use a nitrogen blower to dry, add 5 mL of pure methanol to elute, and store the eluate at low temperature.

[0038] (3) Collect sample mass spectrometry data.

[0039] The test solution was injected into a Fourier transform ion cyclotron resonance mass spectrometer with a resolution greater than 1000000, using negative electrospray ionization mode (ESI-) with a mass-to-charge ratio range (m / z) of 100-1000. The mass spectrum of sample 1 is shown in the attached figure. Figure 1 The mass spectrometry data were exported using the instrument's own software Data Analysis 5.0 (Table 1).

[0040] (4) Perform data quality control.

[0041] Using blank samples as controls, the interference of miscellaneous peaks was deducted, and peaks with a sample detection rate of less than 10% were eliminated. After internal standard correction, high-quality (S / N greater than 6:1) mass-to-charge ratio, peak height and peak area data were retained.

[0042] (5) Use algorithms to identify pollution sources.

[0043] Peak extraction was performed on high-quality mass spectrometry data, and the mass spectrometry peaks were uniformly aligned (as shown in Table 1). Based on the aligned data, the similarity between the kth (k=1, 2, 3, 4…n) water body and the jth (j=1, 2…m) pollution source was calculated using a similarity algorithm. The higher the similarity, the higher the contribution rate of the pollution source to the water body (Table 1).

[0044] The similarity algorithm is:

[0045]

[0046] Among them, W i is the intensity of the ith mass spectrum peak of water, S i is the intensity of the i-th mass spectrum peak of the pollution source.

[0047] Accurately identify the main sources of water pollution. Calculate the contribution rate of the jth pollution source to the n water samples, and use the T test to compare the contribution rate of the jth pollution source to the water body. It can be found that the contribution rate of pollution source 1 is significantly greater than that of pollution source m. Therefore, it can be determined that pollution source 1 is the main pollution source of the water environment in this area, as shown in Table 2.

[0048] Table 1 Sample mass spectrometry data

[0049]

[0050] Table 2 Contribution of pollution sources

[0051]

[0052] (6) Identify the locations of major pollution sources based on cluster analysis.

[0053] The characteristic mass spectrum peaks of the main pollution sources were screened out, and the characteristic mass spectrum peaks were the mass spectrum peaks that appeared in the main pollution sources. The cluster analysis method was used to evaluate the spatial distribution characteristics of the characteristic mass spectrum peaks in the area. The main pollution sources and water samples affected by the main pollution sources were clustered into one category within the 95% confidence interval. The location of the pollution source was determined based on the location where the water samples were collected, and the location of the main pollution source was identified based on the spatial clustering results of the characteristic mass spectrum peaks.

[0054] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for tracing the source of water pollution, characterized in that: The following steps are involved: (1) Collecting water samples from multiple water bodies in the target area and collecting multiple pollution source samples around the water bodies in the target area; and pre-treating the collected multiple water body water samples and multiple pollution source samples; (2) Detecting the dissolved organic carbon concentration of the sample, adjusting the volume of the water sample and the pollution source sample to make the dissolved organic carbon content of each sample consistent, extracting the organic matter in each sample, and preparing the test solution; (3) collecting high-resolution mass spectrometry data of each sample test solution and performing preprocessing; (4) Peak extraction and peak alignment are performed on the high-resolution mass spectrometry data of each sample after pretreatment, and then the similarity between the water sample and the samples of each pollution source is calculated to quantitatively calculate the contribution rate of each pollution source to the water body; (5) Conduct significance tests, compare the contribution rates of various pollution sources, and determine the main and secondary pollution sources of water bodies; (6) Identify the characteristic mass spectrum peaks of the pollution source and determine the location of the main pollution source based on the spatial distribution pattern of the characteristic mass spectrum peaks in the target area.

2. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (1), pre-treating the sample includes filtering the sample through a membrane.

3. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (2), the organic matter in each sample is extracted to prepare a soluble organic matter test solution of each sample, including: connecting a solid phase extraction column to a solid phase extractor, adding 3 mL of methanol to activate the solid phase extraction column, using a vacuum pump to provide power to allow the sample to flow through the solid phase extraction column, drying with a nitrogen blower, and then adding 5 mL of pure methanol to elute to obtain the sample's organic matter test solution.

4. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (3), a Fourier transform ion cyclotron resonance mass spectrometer with a resolution greater than 1,000,000 is used to collect high-resolution mass spectrometric data of each sample, using a negative electrospray ionization mode with a mass-to-charge ratio range of 100-1,000.

5. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (3), the high-resolution mass spectrometry data is preprocessed including: using a blank sample as a control to remove interference from other peaks; removing mass spectrometry peaks with a detection rate of less than 10% in the sample; and retaining the mass-to-charge ratio, peak height and peak area data of the mass spectrometry peak after internal standard correction.

6. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (4), the similarity between the water sample and the samples of each pollution source is calculated, and the contribution rate of each pollution source to the water body is quantitatively calculated, including: The similarity algorithm is used to calculate the similarity between the kth (k=1, 2, 3, 4…n) water body and the jth (j=1, 2…m) pollution source. The similarity algorithm is: Among them, W i is the intensity of the ith mass spectrum peak of water, S i is the intensity of the i-th mass spectrum peak of the pollution source; The similarity between the kth water body and the jth pollution source is taken as the contribution rate of the jth pollution source to the kth water body.

7. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (5), a significance test is used to compare the contribution rate of each pollution source to the water body.

8. The method for tracing the source of water pollution according to claim 1, characterized in that: In step (6), the cluster analysis method is used to obtain the spatial clustering results of the characteristic mass spectrum peaks of the main pollution sources in the target area, and the location of the main pollution sources is determined by determining the water samples affected by the main pollution sources.

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