Method for determining and evaluating environment quality background value of river and lake sediments

Abstract

The invention discloses a river and lake sediment environment quality background value determination and evaluation method, and belongs to the technical field of environment pollution evaluation. Collecting soil of a river and lake to be evaluated or a river and lake buffer zone in the same watershed for analysis to obtain control group data, and taking the control group data as a background reference value; selecting an evaluation point location from the river and lake to be evaluated, collecting sediments and benthonic animals of the evaluation point location, analyzing species composition of the sediments and the benthonic animals to obtain detection group data, and taking the detection group data as an evaluation value; comparing the evaluation value with a background reference value to obtain a pollution value; setting a score assignment standard to assign scores to the pollution value and the benthonic animal diversity, and calculating the score of the evaluation value through a score assignment result; and constructing a river and lake sediment environment quality evaluation index according to the score, and determining the river and lake sediment environment quality condition based on the river and lake sediment environment quality evaluation index. Therefore, the river and lake sediment environment quality condition is comprehensively reflected by improving the accuracy of the background reference and establishing a multi-dimensional index system.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental pollution assessment, and more specifically to a method for determining and assessing background values ​​of river and lake sediment environmental quality. Background Art

[0002] As an important part of the aquatic ecosystem, pollutants such as heavy metals and nutrients accumulated in river and lake sediments can be released back into the water through water disturbance and feeding by benthic organisms, causing secondary pollution to the water quality, thus affecting the health of the entire aquatic ecosystem and the safety of human drinking water. Therefore, accurately and scientifically evaluating the environmental quality of river and lake sediments is extremely important for protecting water resources, maintaining ecological balance, and safeguarding human health.

[0003] Ensuring the accuracy and scientificity of the background benchmark is the basis for sediment environmental quality assessment. At present, there is no unified standard for the selection of background values ​​for evaluation of indicators such as sediment nutrients and heavy metals. For example, when evaluating sediment nitrogen and phosphorus pollution, some studies set the background values ​​of TN and TP to 550 mg and 600 mg / kg in reference to the Canadian Ministry of Environment and Energy (1992) Sediment Environmental Quality Assessment Guide; while some studies set the background values ​​of TN and TP to 1000 mg and 730 mg / kg in reference to the "National River, Lake and Reservoir Sediment Pollution Status Survey and Evaluation". These background values ​​are not only significantly different, but also cannot represent the differences in the basins of different rivers and lakes. Similarly, there are similar problems in sediment heavy metal risk assessment. For example, in the study of the evaluation of heavy metals in Poyang Lake sediments, the reference sources include the soil geochemical background values ​​of Dongting Lake area or Jiangxi Province, the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial)" (GB 15618-2018), etc., which leads to the background value of a certain metal in different studies. Even dozens of times. In addition, after searching, the method for determining the background value of heavy metal elements in lake or reservoir sediments with application number 201510772573.0 uses sediment samples collected from open areas of lakes or reservoirs and the outlets of sub-basins without heavy metal pollution sources as background values ​​after testing, regression analysis, etc. However, this method does not consider the influence of hydrodynamic conditions, and the analyzed data only represent data with a low degree of pollution, and cannot represent background values. On the other hand, this method is only applicable to lakes with a large basin range. For urban lakes with smaller areas, such as Xuanwu Lake and Li Lake, the required sediment samples cannot be collected, which reduces the accuracy and scientificity of the background values ​​obtained. Therefore, providing a scientific, accurate, convenient and adaptable method for determining the background value of river and lake sediments is of great significance for effectively evaluating the environmental quality of river and lake sediments, formulating effective environmental protection policies, and promoting sustainable development.

[0004] At present, there are obvious defects in the indicator system and standardization of sediment environmental quality assessment. In terms of the indicator system, many assessment methods tend to only focus on chemical components such as heavy metals and nutrients, while ignoring the physical properties and biodiversity of sediments. At the same time, with the rapid development of social economy, a large number of new pollutants are discharged into water bodies and eventually accumulate in sediments, which not only changes the physical and chemical properties of sediments, but may also have long-term impacts on aquatic ecosystems. Therefore, the pollution of new pollutants should be fully considered when evaluating sediment environmental quality. In terms of evaluation standardization, the existing assessment methods lack comparability and consistency of results due to inconsistent calculation methods or assessment standards. For example, there are assessment methods that select evaluation indicators through principal component analysis and correlation analysis. However, the indicators selected for different rivers and lakes are significantly different, so the comparability between different rivers and lakes is insufficient. In addition, some assessment methods are too complicated. For example, after searching, a comprehensive assessment method for the ecotoxicity risk of heavy metals in river and lake sediments with application number 201910364910.0 needs to construct a structural equation model when evaluating the ecotoxicity risk of heavy metals in river and lake sediments. A comprehensive evaluation and risk factor identification method for lake sediment environmental quality with application number 202310054810.4 needs to derive the predicted no-effect concentration data of pollutant sediment phase based on the existing database, and reduce the measured pollutant concentration data into three parameters based on the predicted no-effect concentration of pollutant sediment phase. The data acquisition, processing and calculation processes of this method are too professional and complicated, which will lead to a small audience for the method and limited promotion and application. Therefore, integrating indicators of multiple dimensions such as sediment physics, chemistry, biology and new pollutants to establish a comprehensive, simple, scientific and standardized sediment environmental quality assessment system is of far-reaching significance for accurately assessing sediment environmental quality, timely discovering environmental problems and formulating effective environmental protection policies. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the problems in the prior art such as the lack of unified standards for background value selection, which leads to the lack of systematicness, comparability and poor adaptability of river and lake sediment environmental quality assessment methods, the present invention provides a method for determining and assessing the background value of river and lake sediment environmental quality. Soil samples are collected from rivers and lakes to be assessed or from river sections or lake areas in the same basin that meet the water quality requirements of Class III or above, have not been developed and utilized within m years, and have no sewage outlets within n meters upstream and downstream. The soil nutrients, soil heavy metals and new soil pollutants are analyzed as background benchmark values. Multi-dimensional indicators such as physical pollutants, chemical pollutants, new pollutants and biodiversity are further integrated to construct a river and lake sediment environmental quality assessment system, which comprehensively reflects the environmental quality status of river and lake sediments to be assessed.

[0007] 2. Technical solution

[0008] The purpose of the present invention is achieved through the following technical solutions.

[0009] A method for determining and evaluating the background value of river and lake sediment environmental quality comprises the following steps:

[0010] Collect soil from the rivers and lakes to be evaluated or from the buffer zones of rivers and lakes in the same basin, analyze the soil to obtain control group data, and use the control group data as the background baseline value;

[0011] Select assessment points from the rivers and lakes to be assessed, collect sediments and benthic animals at the assessment points, analyze the species composition of sediments and benthic animals to obtain test group data, and use the test group data as the assessment value;

[0012] The assessment value is compared with the background reference value to obtain the pollution value;

[0013] Set scoring standards, assign points to pollution values ​​and benthic animal diversity respectively, and calculate the assessment value based on the scoring results;

[0014] A river and lake sediment environmental quality assessment index is constructed based on the scores of the assessment values, and the river and lake sediment environmental quality status is determined based on the size of the river and lake sediment environmental quality assessment index.

[0015] As a further improvement of the present invention, a river section or lake area is selected from the rivers and lakes to be evaluated or the rivers and lakes in the same basin, which has water quality greater than or equal to Class III, has not been developed and utilized within m years, and has no sewage outlet within n meters upstream and downstream, and soil is collected from the buffer zone of the river section or lake area; wherein m≥15 years and n≤100 meters.

[0016] As a further improvement of the present invention, the control group data includes any one or a combination of at least two of soil nutrients, soil heavy metals and new soil pollutants.

[0017] As a further improvement of the present invention, the detection group data includes any one or a combination of at least two of sediment pH value, sediment nutrients, sediment heavy metals and sediment new pollutants.

[0018] As a further improvement of the present invention, new pollutants are determined based on the pollution sources in the rivers and lakes to be evaluated or in the same watershed; among them, antibiotics are selected for urban life point source pollution; among agricultural non-point source pollution, organochlorine pesticides are selected for the planting industry, and antibiotics are selected for aquaculture and livestock and poultry farming; microplastics are selected for rural life pollution; among industrial point source pollution, polycyclic aromatic hydrocarbons are selected for the chemical industry and food processing industry, drugs are selected for the pharmaceutical industry, perfluorinated compounds are selected for the textile industry, and adsorbable organic halogens are selected for the papermaking industry; microplastics are selected for urban runoff pollution.

[0019] As a further improvement of the present invention, the pollution value includes a nutrient salt pollution value, a heavy metal pollution value, and a new pollutant pollution value;

[0020] The nutrient pollution value W NS =P NS / B NS , P NS is sediment nutrients, B NS It is soil nutrient salt;

[0021] The heavy metal pollution value W HM =P HM / B HM , P HM is the sediment heavy metal, B HM Heavy metals in soil;

[0022] The pollution value of the new pollutant W NP =P NP / B NP , P NP It is a new type of pollutant in sediments, B NP It is a new type of soil pollutant.

[0023] As a further improvement of the present invention, points are assigned to the nutrient pollution value, heavy metal pollution value, new pollutant pollution value and benthic animal diversity according to the scoring standard.

[0024] As a further improvement of the present invention, based on the scoring results, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity are calculated respectively, and the calculation formula is:

[0025]

[0026] Where D is the score, n is the number of sediment nutrients, sediment heavy metals, sediment emerging pollutants and benthic animal diversity involved in the assessment, and F is the i It means to assign points to nutrient pollution value, heavy metal pollution value, new pollutant pollution value and benthic animal diversity.

[0027] As a further improvement of the present invention, in combination with the sediment pH value, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity are weighted and summed to construct the river and lake sediment environmental quality assessment index SEQI; when the pH value is <6 or the pH value is >9, the river and lake sediment environmental quality is assessed to be poor; when 6≤pH value≤9, the river and lake sediment environmental quality is assessed by the river and lake sediment environmental quality assessment index SEQI.

[0028] As a further improvement of the present invention, when SEQI≤1, the environmental quality of river and lake sediments is assessed as poor; when 1<SEQI≤2, the environmental quality of river and lake sediments is assessed as general; when 2<SEQI≤3, the environmental quality of river and lake sediments is assessed as medium; when 3<SEQI≤4, the environmental quality of river and lake sediments is assessed as good; when SEQI>4, the environmental quality of river and lake sediments is assessed as excellent.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the advantages of the present invention are:

[0031] (1) The method for determining and evaluating the background value of river and lake sediment environmental quality of the present invention fully considers the natural conditions, water quality conditions and the impact of human activities in the river and lake basins, and uses the soil of near-natural river sections or lake land buffers that meet the requirements as background value samples to ensure that the obtained background benchmark data is closer to the real and natural environmental state, thereby improving the accuracy and scientificity of the background benchmark, and having strong practicality and wide applicability.

[0032] (2) The method for determining and evaluating the background value of river and lake sediment environmental quality of the present invention integrates multi-dimensional indicators such as physical pollutants, chemical pollutants, emerging pollutants and biodiversity in sediments, and uses an easy-to-operate scoring method to score the multi-dimensional indicators. There is no need for complex data collection, processing and calculation methods, making the evaluation method more comprehensive, systematic, and easy to operate, implement and promote.

[0033] (3) The method for determining and evaluating the background value of river and lake sediment environmental quality of the present invention adopts a unified evaluation standard and calculation method, which ensures the reliability and consistency of the evaluation results, facilitates comparison and analysis between different rivers and lakes, and provides a scientific basis for formulating effective ecological environmental protection policies. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The figure is a flow chart of a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0036] like Figure 1As shown, a method for determining and evaluating the background value of river and lake sediment environmental quality provided by this embodiment. The method includes the following steps: collecting soil from the rivers and lakes to be evaluated or the buffer zones of rivers and lakes in the same basin, analyzing the soil to obtain control group data, and using the control group data as the background reference value; selecting evaluation points from the rivers and lakes to be evaluated, collecting sediments and benthic animals at the evaluation points, analyzing the species composition of sediments and benthic animals to obtain test group data, and using the test group data as the evaluation value; comparing the evaluation value with the background reference value to obtain the pollution value; setting a scoring standard, respectively assigning points to the pollution value and benthic animal diversity, and calculating the score of the evaluation value through the scoring results; constructing a river and lake sediment environmental quality assessment index based on the score of the assessment value, and determining the river and lake sediment environmental quality status based on the size of the river and lake sediment environmental quality assessment index.

[0037] Specifically in this embodiment, in combination with long-term remote sensing data and water quality monitoring data, river sections or lake areas that meet the water quality greater than or equal to Class III, have not been developed and utilized within m years, and have no sewage outlets within n meters upstream and downstream are selected from the rivers and lakes to be evaluated or rivers and lakes in the same basin, and soil is collected from the buffer zone of the river section or lake area, where m≥15 years and n≤100 meters.

[0038] It should be noted that, in this embodiment, the water quality grade classification standard is the existing technology.

[0039] In this embodiment, the number of near-natural river sections or lake areas that meet the requirements needs to be greater than or equal to 10. At the same time, the shortest distance between the area where soil is collected in the land buffer zone and the water level variation area near the natural river section needs to be less than or equal to 1 meter, and the vertical depth of soil collection needs to be greater than or equal to 0.5 meter to ensure the accuracy of the assessment.

[0040] It should be noted that in order to ensure that the collected soil samples are not contaminated or are less contaminated, in this embodiment, it is better to select a near-natural river section or lake area that meets the water quality of Class III or above, has not been developed and utilized within 15 years, and has no sewage outlet within 100 meters upstream and downstream from the rivers and lakes to be evaluated or the rivers and lakes in the same basin, and collect soil from the terrestrial buffer zone of the river section or lake area for analysis to obtain the control group data.

[0041] In this embodiment, the control group data includes any one or a combination of at least two of soil nutrients, soil heavy metals and new soil pollutants. It should be noted that in this embodiment, the data of soil nutrients, soil heavy metals or new soil pollutants obtained by analysis are removed from abnormal data through the existing box plot method, and the average value of non-abnormal data is calculated as the background reference value (B).

[0042] Therefore, in this embodiment, the natural conditions, water quality conditions and impacts of human activities in river and lake basins are fully considered, and the soil of near-natural river sections or lake terrestrial buffers that meet the requirements is used as background value samples to ensure that the obtained background benchmark data is closer to the real and natural environmental conditions, thereby improving the accuracy and scientificity of the background benchmark, and having strong practicality and wide applicability.

[0043] Further, an assessment point is selected from the rivers and lakes to be assessed, sediments and benthic animals at the assessment point are collected, and the species composition of the sediments and benthic animals is analyzed to obtain a detection group data, and the detection group data is used as the assessment value (P). In this embodiment, the detection group data includes any one or a combination of at least two of sediment pH value, sediment nutrients, sediment heavy metals, and sediment new pollutants.

[0044] It should be noted that, in this embodiment, the nutrient data of soil and sediments include total nitrogen and total phosphorus, and the heavy metal data of soil and sediments include Cu, Pb, Zn, Cd, Cr, Hg and As. The assessment indicators of new pollutants in soil and sediments are determined by the pollution sources in the river and lake basins to be assessed. Specifically, antibiotics are selected for urban life point source pollution; in agricultural non-point source pollution, organochlorine pesticides are selected for planting industry, antibiotics are selected for aquaculture and livestock and poultry breeding; microplastics are selected for rural life pollution; in industrial point source pollution, polycyclic aromatic hydrocarbons are selected for chemical industry and food processing industry, drugs are selected for pharmaceutical industry, perfluorinated compounds are selected for textile industry, and adsorbable organic halogens are selected for papermaking industry; microplastics are selected for urban runoff pollution. Therefore, in view of the large number of new pollutants that exist, in this embodiment, only one or several new pollutants need to be selected for assessment, which effectively reduces the assessment workload and improves the assessment efficiency and accuracy.

[0045] In this embodiment, the benthic animal species composition is analyzed by the existing Shannon-Wiener index method to obtain the benthic animal diversity (H) data.

[0046] Furthermore, the evaluation value is compared with the background reference value to obtain a pollution value (W). In this embodiment, the pollution value includes a nutrient salt pollution value, a heavy metal pollution value and a new pollutant pollution value.

[0047] Nutrient pollution value W NS =P NS / B NS , P NS is sediment nutrients, B NS It is soil nutrient salt;

[0048] Heavy metal pollution value W HM =P HM / B HM , P HM is the sediment heavy metal, B HMare heavy metals in the soil;

[0049] Pollution value W of emerging pollutants NP = P NP / B NP where P NP is the emerging pollutant in sediment, and B NP is the emerging pollutant in soil.

[0050] According to the scoring criteria, scores are assigned to the pollution values of nutrients, heavy metals, emerging pollutants, and benthic animal diversity respectively. In this embodiment, the scoring criteria for the pollution values of nutrients, heavy metals, and emerging pollutants are as follows: when W < 1, 5 points are assigned; when 1 ≤ W < 1.5, 4 points are assigned; when 1.5 ≤ W < 2, 3 points are assigned; when 2 ≤ W < 2.5, 2 points are assigned; when W ≥ 2.5, 1 point is assigned. In this embodiment, the benthic animal diversity is scored through the Shannon-Wiener index, and the scoring criteria are as follows: when H > 3, 5 points are assigned; when 2 < H ≤ 3, 4 points are assigned; when 1 < H ≤ 2, 3 points are assigned; when 0 < H ≤ 1, 2 points are assigned; when H = 0, 1 point is assigned.

[0051] Based on the scoring results, scores for sediment nutrients, sediment heavy metals, sediment emerging pollutants, and benthic animal diversity are calculated respectively, and the calculation formula is:

[0052]

[0053] where D represents the score, n represents the number of sediment nutrients, sediment heavy metals, sediment emerging pollutants, and benthic animal diversity participating in the evaluation, and F i represents the operation of assigning scores to the pollution values of nutrients, heavy metals, emerging pollutants, and benthic animal diversity.

[0054] In this embodiment, an environmental quality assessment index for river and lake sediments is constructed based on the score (D) of the evaluation value, and the environmental quality status of river and lake sediments is determined based on the size of the environmental quality assessment index for river and lake sediments. Specifically, in combination with the sediment pH value, the scores of the pollution values of nutrients, heavy metals, emerging pollutants, and benthic animal diversity are weighted and summed to construct the environmental quality assessment index SEQI for river and lake sediments. In particular, in this embodiment, the recommended weights of nutrients, heavy metals, emerging pollutants, and benthic animals are 0.3, 0.3, 0.2, and 0.2 respectively, so that more accurate assessment results can be obtained.

[0055] In this embodiment, when 6≤pH≤9, the river and lake sediment environmental quality is evaluated by the river and lake sediment environmental quality evaluation index. That is, when SEQI≤1, the river and lake sediment environmental quality is evaluated as poor; when 1<SEQI≤2, the river and lake sediment environmental quality is evaluated as general; when 2<SEQI≤3, the river and lake sediment environmental quality is evaluated as medium; when 3<SEQI≤4, the river and lake sediment environmental quality is evaluated as good; when SEQI>4, the river and lake sediment environmental quality is evaluated as excellent.

[0056] In this embodiment, when the pH value is less than 6 or the pH value is greater than 9, the environmental quality of river and lake sediments is directly assessed to be poor.

[0057] Therefore, the method for determining and evaluating the background value of river and lake sediment environmental quality provided in this embodiment integrates multi-dimensional indicators such as physical pollutants, chemical pollutants, new pollutants and biodiversity in sediments, and uses an easy-to-operate scoring method to score the multi-dimensional indicators, without the need for complex data collection, processing and calculation methods, making the evaluation method more comprehensive, systematic, and easy to operate, implement and promote. In addition, the use of unified evaluation standards and calculation methods ensures the reliability and consistency of the evaluation results, facilitates comparison and analysis between different rivers and lakes, and provides a scientific basis for the formulation of effective ecological and environmental protection policies.

[0058] Example 1

[0059] In this example, the lake whose sediment environmental quality is to be assessed is located in a city lake in Jiangsu Province. The lake is about 8.9 km long and has an area of ​​about 3.9 km. 2 . After field investigation and analysis of satellite remote sensing data, the lake is surrounded by artificial parks, woodlands and grasslands. Therefore, combined with long-term satellite remote sensing data and water quality monitoring data, 10 near-natural river sections with water quality of Class III or above, undeveloped within 15 years and no sewage outlet within 100 meters upstream and downstream were selected from the rivers in the same basin of the lake. Soil was collected from the terrestrial buffer zone of 10 river sections within 48 hours. The distance between the area where the soil was collected and the water level fluctuation zone of the river section was 0.8m, and the vertical depth of soil collection was 0.5m. The collected soil was brought back to the laboratory, dried in an oven at 110℃ for 36 hours, and then ground and sieved for analysis. The analysis showed that the main source of pollution in the lake was urban runoff pollution, so the evaluation indicator of new pollutants was microplastics. The pH value, total nitrogen, total phosphorus, Cu, Pb, Zn, Cd, Cr, Hg, As and microplastics of the soil in the terrestrial buffer zone of the 10 river sections, as well as the background benchmark (B) of each indicator after box plot analysis, are shown in Table 1.

[0060] Table 1 Background baseline values ​​of lake sediments (B)

[0061]

[0062] In May 2024, sediment and benthic animal samples were collected from three assessment points in the lake to analyze the sediment pH, nutrient salts, heavy metal and emerging pollutant contents, and benthic animal diversity. The specific assessment values ​​(P) and pollution values ​​(W) are shown in Table 2.

[0063] Table 2 Evaluation value (P) and pollution value (W) of each indicator

[0064]

[0065] The pH values ​​of the sediments at the three assessment points were all between 6 and 9. Therefore, the pollution value (W) and benthic animal diversity index (H) were scored. Based on the scoring results, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity (D) were calculated, as shown in Table 3.

[0066] Table 3 Scoring and scoring of each indicator

[0067]

[0068] Furthermore, the SEQI values ​​of the three assessment points were calculated based on the recommended weights of nutrients, heavy metals, emerging pollutants and benthic animals, which were 3.65, 4.67 and 3.90, respectively. According to the evaluation levels, the sediment environmental qualities of the three assessment points were in good, excellent and good conditions, respectively.

[0069] Example 2

[0070] In this embodiment, the river whose sediment environmental quality is to be evaluated is located in the northern part of Anhui Province, and the length of the river is about 93 km. After field investigation and satellite remote sensing data analysis, the upper reaches of the river are in urban areas, and the two banks are artificially constructed parks, woodlands and grasslands; the middle and lower reaches are in rural areas, and there are natural rivers. Therefore, combined with long-term satellite remote sensing data and water quality monitoring data, 10 near-natural river sections that meet the water quality of Class III or above, have not been developed and utilized within 15 years, and have no sewage outlets within 100 meters upstream and downstream are selected in the middle and lower reaches of the river. Soil was collected from the land buffer zone of 10 river sections within 48 hours. The distance between the area where the soil was collected and the water level fluctuation area of ​​the river section was 0.8m, and the vertical depth of soil collection was 0.5m. The collected soil was brought back to the laboratory, placed in an oven at 110°C and dried for 36 hours, and then ground and sieved for analysis. The analysis showed that the pollution sources of the river include urban life point sources, agricultural non-point sources, rural life, chemical industry and urban runoff pollution. Therefore, the evaluation indicators of new pollutants are antibiotics, organochlorine pesticides, microplastics and polycyclic aromatic hydrocarbons. The contents of various soil indicators in the land buffer zones of the 10 river sections and the background benchmark (B) obtained after box plot analysis are shown in Table 4.

[0071] Table 4 River sediment background standard (B)

[0072]

[0073] In November 2023, sediment and benthic animal samples were collected from three assessment points in the upper, middle and lower reaches of the river to analyze the sediment pH, nutrient, heavy metal and emerging pollutant contents, and benthic animal diversity. The specific assessment values ​​(P) and pollution values ​​(W) are shown in Table 5.

[0074] Table 5 Evaluation value (P) and pollution value (W) of each indicator

[0075]

[0076] The pH values ​​of the sediments at the three assessment points were all between 6 and 9. Therefore, the pollution value (W) and benthic animal diversity index (H) were scored. Based on the scoring results, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity (D) were calculated, as shown in Table 6.

[0077] Table 6: Scoring and scoring of each indicator

[0078]

[0079] Furthermore, according to the recommended weights of nutrients, heavy metals, emerging pollutants and benthic animals, the SEQI values ​​of the three assessment points were calculated to be 2.34, 3.91 and 4.52, respectively. According to the evaluation levels, the sediment environmental qualities of the three assessment points were respectively medium, good and excellent.

[0080] In addition, the average SEQI value of the river is 3.58, which is in good condition and lower than the average SEQI value of the lake in Example 1. It can be seen that the environmental quality of the lake sediments in Example 1 is better than that in Example 2.

[0081] The above schematically describes the invention and its implementation methods, which is not restrictive. Without departing from the spirit or basic features of the invention, the invention can be implemented in other specific forms. What is shown in the accompanying drawings is only one of the implementation methods of the invention. The actual structure is not limited thereto, and any figure mark in the claims should not limit the claims involved. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the purpose of the invention, a structural method and an embodiment similar to the technical solution are designed without creativity, which should all belong to the protection scope of the present invention. In addition, the word "including" does not exclude other elements or steps, and the word "one" before the element does not exclude the inclusion of "multiple" elements. The multiple elements stated in the product claim can also be implemented by one element through software or hardware. The words first, second, etc. are used to indicate the name, and do not indicate any specific order.

Claims

1. A method for determining and evaluating the background value of river and lake sediment environmental quality, comprising the following steps: Collect soil from the rivers and lakes to be evaluated or from the buffer zones of rivers and lakes in the same basin, analyze the soil to obtain control group data, and use the control group data as the background baseline value; Select assessment points from the rivers and lakes to be assessed, collect sediments and benthic animals at the assessment points, analyze the species composition of sediments and benthic animals to obtain test group data, and use the test group data as the assessment value; The assessment value is compared with the background reference value to obtain the pollution value; Set scoring standards, assign points to pollution values ​​and benthic animal diversity respectively, and calculate the assessment value based on the scoring results; A river and lake sediment environmental quality assessment index is constructed based on the scores of the assessment values, and the river and lake sediment environmental quality status is determined based on the size of the river and lake sediment environmental quality assessment index.

2. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 1, characterized in that: Select river sections or lake areas that meet the water quality requirements of Class III or above, have not been developed or utilized within m years, and have no sewage outlets within n meters upstream and downstream from the rivers and lakes to be assessed or rivers and lakes in the same basin, and collect soil from the buffer zone of the river section or lake area; m ≥ 15 years, n ≤ 100 meters.

3. The method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 1, characterized in that: The control group data includes any one or a combination of at least two of soil nutrients, soil heavy metals and new soil pollutants.

4. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 1, characterized in that: The detection group data includes any one or a combination of at least two of sediment pH value, sediment nutrients, sediment heavy metals and sediment new pollutants.

5. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 4, characterized in that: New pollutants are determined based on pollution sources in the rivers and lakes to be assessed or in the same river basin; among them, antibiotics are selected for urban living point source pollution; among agricultural non-point source pollution, organochlorine pesticides are selected for the planting industry, and antibiotics are selected for aquaculture and livestock and poultry farming; microplastics are selected for rural living pollution; among industrial point source pollution, polycyclic aromatic hydrocarbons are selected for the chemical industry and food processing industry, drugs are selected for the pharmaceutical industry, perfluorinated compounds are selected for the textile industry, and adsorbable organic halogens are selected for the papermaking industry; microplastics are selected for urban runoff pollution.

6. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claims 3-5, characterized in that: The pollution values ​​include nutrient pollution values, heavy metal pollution values, and new pollutant pollution values; The nutrient pollution value W NS =P NS / B NS , P NS is sediment nutrients, B NS It is soil nutrient salt; The heavy metal pollution value W HM =P HM / B HM , P HM is the sediment heavy metal, B HM Heavy metals in soil; The pollution value of the new pollutant W NP =P NP / B NP , P NP It is a new type of pollutant in sediments, B NP It is a new type of soil pollutant.

7. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 6, characterized in that: According to the scoring standards, points are assigned to nutrient pollution values, heavy metal pollution values, new pollutant pollution values ​​and benthic animal diversity respectively.

8. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 7, characterized in that: Based on the scoring results, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity were calculated respectively. The calculation formula is: Where D is the score, n is the number of sediment nutrients, sediment heavy metals, sediment emerging pollutants and benthic animal diversity involved in the assessment, and F is the i It means to assign points to nutrient pollution value, heavy metal pollution value, new pollutant pollution value and benthic animal diversity.

9. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 8, characterized in that: Combined with the sediment pH value, the scores of sediment nutrients, sediment heavy metals, sediment new pollutants and benthic animal diversity are weighted and summed to construct the river and lake sediment environmental quality assessment index SEQI; when the pH value is <6 or the pH value is >9, the river and lake sediment environmental quality is assessed as poor; when 6≤pHvalue≤9, the river and lake sediment environmental quality is assessed by the river and lake sediment environmental quality assessment index SEQI.

10. A method for determining and evaluating the background value of river and lake sediment environmental quality according to claim 9, characterized in that: When SEQI≤1, the environmental quality of river and lake sediments is assessed as poor; when 1<SEQI≤2, the environmental quality of river and lake sediments is assessed as fair; when 2<SEQI≤3, the environmental quality of river and lake sediments is assessed as medium; when 3<SEQI≤4, the environmental quality of river and lake sediments is assessed as good; when SEQI>4, the environmental quality of river and lake sediments is assessed as excellent.

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