A water environment quality evaluation method based on physical and chemical indicators

Abstract

The present invention discloses a water environment quality evaluation method based on physical and chemical indicators, which relates to the technical field of surface water quality safety evaluation. The method includes determining the type of water body to be evaluated; determining the selected indicators for water environment quality evaluation based on the water body type and the actual pollution situation, the selected indicators include mandatory indicators and reference indicators; collecting data and conducting special investigations on the selected indicators so that the selected indicator data meet the evaluation requirements; calculating the comprehensive pollution status indicators, comprehensive nutritional status indicators, organic pollutant risk status and heavy metal risk status indicators, and classifying them based on the calculation results; and evaluating the water environment quality based on the classification results. The present invention realizes high-accuracy and rapid water quality evaluation by taking the comprehensive indicators of multiple water quality physical and chemical pollutants as the core, and solves the drawbacks of the existing single-factor water quality evaluation technology, which has few indicators, is too strict, and the calculation process of the comprehensive evaluation method involves many parameters and indicators and is difficult to achieve.

Description

Technical Field

[0001] The present invention relates to the technical field of surface water quality safety assessment, and in particular to a water environment quality assessment method based on physical and chemical indicators. Background Art

[0002] Water quality assessment is the basic work of water environment management. Only by adopting scientific and reasonable water quality assessment methods can we accurately reflect the current water quality and pollution status, and find out the main pollution problems in combination with the changes in water quality, so as to provide a basis for water pollution control, water function zoning, water environment planning and water environment management. When evaluating whether the water quality is safe, it is often necessary to determine whether the concentration of various pollutants contained in the evaluated surface water area is within the required maximum limit.

[0003] The methods used in traditional surface water environmental quality evaluation mainly include single factor method and comprehensive evaluation method, which have played a certain positive role in water quality evaluation. For example, the single factor evaluation method is the main method for current surface water quality evaluation. It generally adopts the excess index method and selects the evaluation result of the worst water quality factor among multiple evaluation factors as the comprehensive evaluation result. The method is simple and intuitive. However, the evaluation result mainly depends on the most serious pollution factor, and the role of other factors is weakened, and its evaluation effect is too strict. The comprehensive evaluation methods, such as water pollution index method, hierarchical analysis method, multivariate statistical analysis method, grey correlation method and artificial neural network method, are still in the theoretical research stage, and have not formed a unified and standardized water quality comprehensive evaluation model, and cannot be applied in actual management. Therefore, the existing water quality evaluation technology still has problems such as the calculation results are prone to deviation, the calculation process involves many parameters and indicators and is difficult to implement, which is not conducive to the rapid and accurate evaluation of whether the water quality is safe.

[0004] In addition, conventional water quality evaluation methods are mainly based on physical chemistry, and only use the pollutants listed in the surface water environmental quality standards as evaluation criteria, and are divided into five levels: I, II, III, IV, and V. Generally, only a few indicators can be used as reference values ​​to determine the overall water quality status of the water body. However, the current surface water environmental quality standards do not list new pollutants that pose a major risk to the aquatic environment, especially those that are toxic, persistent, and easily bioaccumulated and biomagnified by organisms. At the same time, for heavy metals related to hardness, the comprehensive risks they pose are not considered, which is unreasonable to a certain extent for the overall control of water quality.

[0005] Therefore, in response to the existing problems, a comprehensive optimization evaluation method for water environment quality is proposed, which takes physical and chemical pollutant indicators as the core and is based on water quality benchmarks or water quality standards, which can achieve high-accuracy and rapid water quality evaluation. Summary of the invention

[0006] The present invention aims at solving the problems in the prior art and provides a water environment quality evaluation method based on physical and chemical indicators.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A water environment quality evaluation method based on physical and chemical indicators comprises the following steps: step S1, determining the type of water body to be evaluated; step S2, determining the selected indicators for water environment quality evaluation based on the water body type and the actual pollution situation, wherein the selected indicators include mandatory indicators and reference indicators; step S3, collecting data and conducting special investigations on the selected indicators, so that the selected indicator data meet the evaluation requirements; step S4, calculating the comprehensive pollution status index, the comprehensive nutritional status index, the organic pollutant risk status index and the heavy metal risk status index, and dividing the levels based on the calculation results, wherein the levels are divided into the first level, the second level, the third level, the fourth level and the fifth level; step S5, evaluating the water environment quality based on the division results, wherein the smaller the level, the better the water environment quality.

[0009] Based on the above technical solution, further, in step S1, the water body types include lakes, reservoirs, rivers and estuaries.

[0010] Based on the above technical solution, further, in step S2, the mandatory indicators include at least comprehensive pollution status indicators, comprehensive nutritional status indicators and comprehensive pollution status indicators, and the reference indicators include at least heavy metal risk status indicators and organic pollutant risk status indicators, wherein the reference indicators are screened and determined based on the degree of water pollution and management needs; other pollutants except the mandatory indicators, if their concentration exceeds the surface water quality standard limit, or there is a risk for pollutants that are not included in the management, they will be listed as reference indicators.

[0011] Based on the above technical solution, further, the mandatory indicators for lakes and reservoirs include comprehensive pollution status indicators and comprehensive nutrient status indicators, and the mandatory indicators for rivers and estuaries include comprehensive pollution status indicators; the reference indicators for lakes, reservoirs, rivers and estuaries all include heavy metal risk status indicators and organic pollutant risk status indicators.

[0012] Based on the above technical solution, further, in step S4, the calculation process of the comprehensive pollution status index includes the following steps:

[0013] Step S41, calculate the water quality exceeding standard range F1: F1 = 100 × (m / M); wherein F1 represents the exceeding water quality index range; m represents the number of monitoring indexes exceeding the standard; M represents the number of indexes included in the evaluation;

[0014] Step S42, calculate the frequency of exceeding the standard F2: F2 = 100 × (n / N); where F2 represents the frequency of exceeding the standard of the water quality parameter; n represents the sum of the number of times each indicator exceeds the standard; and N represents the total number of monitoring times;

[0015] Step S43, calculate the excess amplitude F3: F3 = nse / (0.01nse+0.01), where nse is the standardized index offset; Step S44, comprehensive pollution status index Where WQI is dimensionless.

[0016] Based on the above technical solution, further, in step S4, the calculation process of the comprehensive nutritional status index is:

[0017] According to the concentration values ​​of chlorophyll, total phosphorus, total nitrogen, transparency and permanganate index, the single nutritional status is calculated respectively. The formula is as follows:

[0018]

[0019] In the formula, ρ chla Indicates the concentration of chlorophyll a, in mg / 1; ρ TN Indicates the total nitrogen concentration value, the unit is mg / 1; ρ TP Indicates the total phosphorus concentration value, the unit is mg / 1; D SD Indicates transparency, unit is m; ρ IMn Indicates the permanganate index concentration value, in mg / 1;

[0020] Among them, the comprehensive nutritional status is obtained by the weighted sum of each individual nutritional status, and the formula is as follows: Where: TLI(∑) represents the comprehensive nutritional status; TLI(j) represents the single nutritional status of the jth indicator; m1 represents the number of indicators; W j Represents the relevant weight of the single nutritional status of the jth indicator, and its value is: W chla =0.5996; W TN =0.0718; W TP =0.137; W SD =0.0075; W IMn =0.1840.

[0021] Based on the above technical solution, further, in step S4, the calculation process of the heavy metal risk status index is: In the formula, R M Indicates the comprehensive risk status of heavy metals in water bodies; C Mi It indicates the concentration of heavy metal i in the water body within the assessment unit. If multiple monitoring sections are involved, the average value of each section is taken. The unit is mg / l; S MiIt represents the maximum allowable concentration of heavy metal i in water within the evaluation unit, with the unit of mg / l.

[0022] Based on the above technical solution, further, in step S4, the calculation process of the risk status index of organic pollutants is as follows:

[0023] In the formula, R o represents the comprehensive risk status of organic pollutants; C oi represents the concentration of the i-th organic pollutant in the water body within the evaluation unit. If there are multiple monitoring sections, the average value of each section is taken, with the unit of mg / l; S oi represents the maximum allowable concentration of the i-th organic pollutant in the water body within the evaluation unit, with the unit of mg / l.

[0024] Based on the above technical solution, further, in step S5, level conditions are respectively set for the comprehensive pollution status index, the comprehensive trophic state index, the heavy metal risk status index, and the organic pollutant risk status.

[0025] Under level condition one: the calculation result of the comprehensive pollution status index satisfies 95 ≤ WQI ≤ 100, the calculation result of the comprehensive trophic state index satisfies TLI(∑) < 30, the calculation result of the heavy metal risk status index satisfies R M < 0.3, and the calculation result of the organic pollutant risk status index satisfies R O < 0.3;

[0026] Under level condition two: the calculation result of the comprehensive pollution status index satisfies 80 ≤ WQI < 95, the calculation result of the comprehensive trophic state index satisfies 30 ≤ TLI(∑) ≤ 50, the calculation result of the heavy metal risk status index satisfies 0.3 ≤ R M < 0.7, and the calculation result of the organic pollutant risk status index satisfies 0.3 ≤ R o < 0.7;

[0027] Under level condition three: the calculation result of the comprehensive pollution status index satisfies 65 ≤ WQI < 80, the calculation result of the trophic state index satisfies 50 < TLI(∑) ≤ 60, the calculation result of the heavy metal risk status index satisfies 0.7 ≤ R M < 1, and the calculation result of the organic pollutant risk status index satisfies 0.7 ≤ R o < 1;

[0028] Under level condition four: the calculation result of the comprehensive pollution status index satisfies 45 ≤ WQI < 65; the calculation result of the trophic state index satisfies 60 < TLI(∑) ≤ 70, the calculation result of the heavy metal risk status index satisfies 1 ≤ R M < 1.5, and the calculation result of the organic pollutant risk status index satisfies 1 ≤ Ro <1.5;

[0029] Under level five conditions: the calculation result of the comprehensive pollution status index satisfies 0≤WQI<45.

[0030] Based on the above technical solution, further, in step S5, the water quality evaluation level classification process is as follows:

[0031] 1. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions one, the water quality evaluation level is determined to be the first level;

[0032] 2. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the second level condition, the water quality evaluation level is determined to be the second level;

[0033] Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition one, and any one or two of the three indicators, including the calculation result of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index, meet the corresponding level condition two, the water quality evaluation level is determined to be the second level;

[0034] Alternatively, when the calculation result of the comprehensive pollution status index meets the second level condition, and any one of the calculation results of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index meets the corresponding second level condition, and the calculation results of the remaining indicators at least meet the third level condition, then the water quality evaluation level is determined to be the second level;

[0035] Alternatively, when the calculation results of the comprehensive pollution status index meet the second level condition, and the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the third level condition respectively, the water quality evaluation level is determined to be the second level;

[0036] 4. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions three, the water quality evaluation level is determined to be the third level;

[0037] Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition one, and at least two of the three indicators, namely, the calculation result of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index, meet the corresponding level condition four, the water quality evaluation level is determined to be the third level;

[0038] Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition 2, and at least one of the calculation results of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index meets the corresponding level condition 4, the water quality evaluation level is determined to be the third level;

[0039] 4. When the calculation result of the comprehensive pollution status index meets the fourth level condition, the water quality evaluation level is determined to be the fourth level regardless of whether the other indicators meet the corresponding second or third level conditions;

[0040] 5. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions 4, the water quality evaluation level is determined to be the fifth level;

[0041] Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition five, the water quality evaluation level is determined to be the fifth level.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention adopts comprehensive indicators of multiple water quality physical and chemical pollutants as the core, improves the new pollutant indicators that are not considered in traditional water quality evaluation methods and do not include them in management, takes into account the comprehensive risk factors of comprehensive pollution status indicators, comprehensive nutritional status indicators, organic pollutant risk status indicators and heavy metal risk status indicators, and achieves high-accuracy and rapid water quality evaluation, solving the problems of existing single-factor water quality evaluation technology, such as few indicators, excessive strictness, and the comprehensive evaluation method calculation process involving many parameters and indicators and being difficult to achieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The figure is a flow chart of the evaluation method of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0046] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0047] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0048] Example

[0049] Combination Figure 1 As shown, a water environment quality evaluation method based on physical and chemical indicators is implemented, including the following steps:

[0050] Step S1, determining the type of water body to be evaluated; wherein the water body types include lakes, reservoirs, rivers and estuaries, and the definitions of these four types of water bodies can be obtained from some standard documents, such as the document "Ecological Monitoring Technical Guidelines - River Aquatic Biological Monitoring and Evaluation (Trial)" etc.;

[0051] Step S2, determine the selected indicators for water environment quality evaluation based on the water body type and actual pollution situation, wherein the selected indicators include mandatory indicators and reference indicators; specifically, the mandatory indicators include at least comprehensive pollution status indicators, comprehensive nutrient status indicators and comprehensive pollution status indicators, and the reference indicators include at least heavy metal risk status indicators and organic pollutant risk status indicators, wherein the reference indicators are screened and determined according to the degree of water pollution and management needs; other pollutants other than the mandatory indicators, if their concentration exceeds the limit of surface water quality standards, or there is a risk for pollutants that are not included in the management, are listed as reference indicators. The mandatory indicators for lakes and reservoirs include comprehensive pollution status indicators and comprehensive nutrient status indicators, and the mandatory indicators for rivers and estuaries include comprehensive pollution status indicators; the reference indicators for lakes, reservoirs, rivers and estuaries all include heavy metal risk status indicators and organic pollutant risk status indicators.

[0052] Step S3, collect data and conduct special research on the selected indicators; the collection and research are to ensure that the data can meet the evaluation requirements, and also to understand the actual pollution status of the water body and determine whether to increase reference indicators.

[0053] Step S4, calculating the comprehensive pollution status index, the comprehensive nutritional status index, the organic pollutant risk status index and the heavy metal risk status index, and classifying them into levels based on the calculation results, wherein the levels are divided into the first level, the second level, the third level, the fourth level and the fifth level.

[0054] Specifically, the calculation process of each indicator is as follows:

[0055] The calculation process of the comprehensive pollution status index includes the following steps:

[0056] Step S41, calculate the water quality exceeding standard range F1: F1 = 100 × (m / M); wherein F1 represents the exceeding water quality index range; m represents the number of monitoring indexes exceeding the standard; M represents the number of indexes included in the evaluation;

[0057] Step S42, calculate the frequency of exceeding the standard F2: F2 = 100 × (n / N); where F2 represents the frequency of exceeding the standard of the water quality parameter; n represents the sum of the number of times each indicator exceeds the standard; and N represents the total number of monitoring times;

[0058] Step S43, calculate the excess amplitude F3: F3 = nse / (0.01nse+0.01), where nse is the standardized index deviation; the specific calculation process is: Step 1, when the test value of the water quality monitoring index value is greater than the evaluation standard value, it is called deviation e i , and is calculated by two equations, involving two cases. The first case is: if the test value must not exceed the evaluation standard, that is, when the evaluation standard value is the upper limit: e i =C i / C si -1; where C i Indicates that the indicator exceeds the standard value; C si Indicates the evaluation standard. The second case is: for the case where the test value must not be lower than the evaluation standard value, when the evaluation standard value is the lower limit: e i =C si / C i -1. Step 2, nse is the standardized indicator deviation, which is calculated by adding the deviations of individual tests relative to their evaluation standard values ​​and dividing by the total number of tests (those that met and failed to meet their targets): nse = ∑e i / N; In the third step, F3 is calculated as an asymptotic function that scales the normalization and nse from the target offset to produce a range between 0 and 100: F3 = nse / (0.01nse+0.01);

[0059] Step S44: The comprehensive pollution status can be obtained from the following equation, where the change in the index is proportional to the change in all three factors. Comprehensive pollution status index Where WQI is dimensionless, 1.732 is a scaling factor that normalizes the value to a range between 0 and 100, where 0 represents the worst water quality and 100 represents the best water quality.

[0060] The calculation process of the comprehensive nutritional status index is as follows: based on the concentration values ​​of the five individual indicators of chlorophyll, total phosphorus, total nitrogen, transparency and permanganate index, the individual nutritional status is calculated respectively. The formula is as follows:

[0061]

[0062] In the formula, ρ chla Indicates the concentration of chlorophyll a, in mg / 1; ρ TN Indicates the total nitrogen concentration value, the unit is mg / 1; ρ TP Indicates the total phosphorus concentration value, the unit is mg / 1; D SD Indicates transparency, unit is m; ρ IMn It represents the concentration value of permanganate index, in mg / 1; the comprehensive nutritional status is the weighted sum of each individual nutritional status, and the formula is as follows: Where: TLI(∑) represents the comprehensive nutritional status; TLI(j) represents the single nutritional status of the jth indicator; m1 represents the number of indicators; W j Represents the relevant weight of the single nutritional status of the jth indicator, and its value is: W chla =0.5996; W TN =0.0718; W TP =0.137; W SD =0.0075; W IMn =0.1840.

[0063] The calculation process of heavy metal risk status index is as follows: In the formula, R M Indicates the comprehensive risk status of heavy metals in water bodies; C Mi It indicates the concentration of heavy metal i in the water body within the assessment unit. If multiple monitoring sections are involved, the average value of each section is taken. The unit is mg / l; S MiIt represents the maximum allowable concentration of heavy metal i in water in the evaluation unit, with the unit of mg / l. For the maximum reference concentration of heavy metals with benchmarks, refer to the existing short-term benchmark values; for heavy metals with hardness-based benchmarks (such as Cd, Cr, Cu, Pb, Ni, Ag, Zn, etc.), use the hardness of the actual water body (or calculate based on calcium and magnesium concentration data), and calculate its short-term benchmark value using the benchmark and hardness-related formula. For heavy metals without benchmarks, refer to the corresponding Class III standard values in GB 3838. For heavy metals without both benchmark values and standard values, the short-term benchmark value derivation adopts the "Technical Guidelines for Deriving Water Quality Criteria for Freshwater Organisms" (HJ 831-2022).

[0064] The calculation process for the risk status index of organic pollutants is as follows: In the formula, R o represents the comprehensive risk status of organic pollutants; C oi represents the concentration of the i-th organic pollutant in the water body in the evaluation unit. If multiple monitoring sections are involved, take the average value of each section, with the unit of mg / l; S oi represents the maximum allowable concentration of the i-th organic pollutant in the water body in the evaluation unit, with the unit of mg / l.

[0065] The specific process of classification and evaluation is as follows: Level conditions are set for the comprehensive pollution status index, comprehensive trophic state index, heavy metal risk status index, and organic pollutant risk status respectively. Under Level Condition 1: The calculation result of the comprehensive pollution status index satisfies 95 ≤ WQI ≤ 100, the calculation result of the comprehensive trophic state index satisfies TLI(∑) < 30, the calculation result of the heavy metal risk status index satisfies R M < 0.3, and the calculation result of the organic pollutant risk status index satisfies R O < 0.3. Under Level Condition 2: The calculation result of the comprehensive pollution status index satisfies 80 ≤ WQI < 95, the calculation result of the comprehensive trophic state index satisfies 30 ≤ TLI(∑) ≤ 50, the calculation result of the heavy metal risk status index satisfies 0.3 ≤ R M < 0.7, and the calculation result of the organic pollutant risk status index satisfies 0.3 ≤ R o < 0.7. Under Level Condition 3: The calculation result of the comprehensive pollution status index satisfies 65 ≤ WQI < 80, the calculation result of the trophic state index satisfies 50 < TLI(∑) ≤ 60, the calculation result of the heavy metal risk status index satisfies 0.7 ≤ R M < 1, and the calculation result of the organic pollutant risk status index satisfies 0.7 ≤ R o < 1. Under Level Condition 4: The calculation result of the comprehensive pollution status index satisfies 45 ≤ WQI < 65; the calculation result of the trophic state index satisfies 60 < TLI(∑) ≤ 70, and the calculation result of the heavy metal risk status index satisfies 1 ≤ RM <1.5, the calculation result of the organic pollutant risk status index satisfies 1≤R o <1.5. Under level 5: the calculation result of the comprehensive pollution status index satisfies 0≤WQI<45.

[0066] Furthermore, based on the level conditions, the classification is judged, where the first level, second level, third level, fourth level and fifth level can be represented as excellent, good, general, poor and extremely poor, that is, the lower the level number, the better the water quality. The specific judgment process is as follows:

[0067] 1. When the calculation results of the comprehensive pollution status index, the comprehensive nutrient status index, the heavy metal risk status index, and the organic pollutant risk status index all meet the corresponding level conditions one, the water quality evaluation level is determined to be the first level.

[0068] 2. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the level condition 2, the water quality evaluation level is determined to be the second level. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition 1, and any one or two of the three indicators of the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index meet the corresponding level condition 2, the water quality evaluation level is determined to be the second level. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition 2, and any one of the three indicators of the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index meets the corresponding level condition 2, and the calculation results of the remaining indicators at least meet the level condition 3, the water quality evaluation level is determined to be the second level. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition two, and the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the level condition three respectively, the water quality evaluation level is determined to be the second level.

[0069] 3. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions three, the water quality evaluation level is determined to be the third level. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition one, and at least two of the three indicators of the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index meet the corresponding level condition four, the water quality evaluation level is determined to be the third level. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition two, and at least one of the three indicators of the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index meet the corresponding level condition four, the water quality evaluation level is determined to be the third level.

[0070] 4. When the calculation result of the comprehensive pollution status index meets the level four condition, the water quality evaluation level is determined to be the fourth level regardless of whether other indicators meet the corresponding level two or level three conditions.

[0071] 5. When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions 4, the water quality evaluation level is determined to be level 5. Alternatively, when the calculation results of the comprehensive pollution status index meet the level condition 5, the water quality evaluation level is determined to be level 5.

[0072] Step S5: Evaluate the water environment quality based on the classification result, and the smaller the grade, the better the water environment quality.

[0073] For example, taking the data of 10 sampling points in a lake in the Yangtze River Basin in mid-to-late August 2022 as an example, the water quality of the 10 sections is evaluated using the water quality evaluation method in this article. The relevant indicators calculated and the grade classification are combined as shown in Tables 1 to 5 below:

[0074] Table 1 Water quality parameters of a certain water area (mg / l)

[0075] ID DO pH COD F- Cl- SO42- Ammonia nitrogen WQ grade Section 1 8.93 8.44 6.43 0.20 8.48 10.20 0.044 100 excellent Section 2 10.4 8.84 9.73 0.31 15.07 19.85 0.037 100 excellent Section 3 8.79 6.81 4.08 0.29 14.50 16.75 0.009 100 excellent Section 4 9.8 8.27 4.08 0.24 21.81 23.08 0.034 100 excellent Section 5 9.48 8.1 3.77 0.26 16.21 18.43 0.015 100 excellent Section 6 9.54 8.36 4.55 0.28 15.99 24.34 0.069 100 excellent Section 7 9.37 8.18 5.96 0.22 12.19 10.06 0.037 100 excellent Section 8 8.88 7.65 - 0.28 14.31 18.40 - 100 excellent Section 9 8.48 8.31 4.71 0.19 9.46 10.84 0.110 100 excellent Section 10 10.3 7.67 3.29 0.22 15.23 16.35 0.011 100 excellent

[0076] Through this data, we can know that the comprehensive pollution index of the 10 sections of the lake is 100, and all sections are not polluted by the physical indicators of water quality.

[0077] Table 2 Comprehensive nutritional status (mg / l)

[0078]

[0079]

[0080] Through this data, we can know that the eutrophication levels of these 10 sections are different. Section 10 has the lowest eutrophication level and the best water quality.

[0081] Table 3 Heavy metal concentration and comprehensive risk status (ug / l)

[0082]

[0083]

[0084] From this data, we can know that there is no heavy metal risk in these 10 sections.

[0085] Table 4 Organic pollutant concentration and comprehensive risk status (ug / l)

[0086] Sample Point Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 Section 8 Section 9 Section 10 TDCIPP 646.18 2505.38 869.17 1038.08 194.94 333.38 273.71 927.21 727.92 1351.98 R0 1.56 6.07 2.10 2.51 0.47 0.81 0.66 2.25 1.76 3.27 grade Very bad Very bad Very bad Very bad good generally good Very bad Very bad Very bad

[0087] From this data, we can know that these 10 sections all have the risk of organic pollutant organophosphate to varying degrees.

[0088] Then determine the water quality evaluation levels corresponding to the 10 sections to complete the evaluation of surface water quality.

[0089] Table 5 Water quality evaluation levels at different sites

[0090]

[0091] Through this data, we can know that the water quality level of a certain water area under evaluation is different in different sections.

[0092] Based on all the data above, it can be analyzed that through this water environment quality evaluation method, among the 10 sections of a lake, the water quality grades of Section 5, Section 6 and Section 7 are good, and the water quality grades of the remaining sections are poor.

[0093] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A water environment quality evaluation method based on physical and chemical indicators, characterized in that: The following steps are involved: Step S1, determining the type of water body to be evaluated; Step S2: Determine the selected indicators for water environment quality evaluation based on the water body type and actual pollution situation, wherein the selected indicators include mandatory indicators and reference indicators; Step S3: collect data and conduct special research on the selected indicators, so that the selected indicator data meets the evaluation requirements; Step S4, calculating the comprehensive pollution status index, the comprehensive nutritional status index, the organic pollutant risk status index and the heavy metal risk status index, and classifying them into levels based on the calculation results, wherein the levels are divided into the first level, the second level, the third level, the fourth level and the fifth level; The calculation process of the comprehensive pollution status index includes the following steps: Step S41, calculate the water quality exceeding standard range F1: F1=100×(m / M); wherein F1 represents the exceeding standard water quality index range; m represents the number of monitoring indexes exceeding the standard; M represents the number of indexes included in the evaluation; Step S42, calculate the frequency of exceeding the standard F2: F2=100×(n / N); where F2 represents the frequency of exceeding the standard of the water quality parameter; n represents the sum of the number of times each indicator exceeds the standard; N represents the total number of monitoring times; Step S43, calculating the excess amplitude F3: F3=nse / (0.01nse+0.01), where nse is the standardized index deviation; Step S44, comprehensive pollution status index WQI = 100- , where WQI is dimensionless; The calculation process of the comprehensive nutritional status index is as follows: According to the concentration values ​​of chlorophyll, total phosphorus, total nitrogen, transparency and permanganate index, the single nutritional status is calculated respectively. The formula is as follows: In the formula, Indicates the concentration value of chlorophyll a, the unit is mg / 1; Indicates the total nitrogen concentration value, the unit is mg / 1; Indicates the total phosphorus concentration value, the unit is mg / 1; Indicates transparency, unit is m; Indicates the permanganate index concentration value, in mg / 1; Among them, the comprehensive nutritional status is obtained by the weighted sum of each individual nutritional status, and the formula is as follows: ; Where: TLI (∑) represents the comprehensive nutritional status; TLI (j) represents the single nutritional status of the jth indicator; m1 represents the number of indicators; W j Represents the relevant weight of the single nutritional status of the jth indicator, and its value is: W chla =0.5996; W TN =0.0718; W TP =0.137; W SD =0.0075; W IMn =0.1840; The calculation process of heavy metal risk status index is as follows: ; In the formula, R M Indicates the comprehensive risk status of heavy metals in water bodies; C Mi It indicates the concentration of heavy metal i in the water body within the assessment unit. If multiple monitoring sections are involved, the average value of each section is taken. The unit is mg / l; S Mi It indicates the maximum allowable concentration of heavy metal i in water within the assessment unit, in mg / l; The calculation process of the organic pollutant risk status index is as follows: ; In the formula, R o Indicates the comprehensive risk status of organic pollutants; C oi It represents the concentration of the ith organic pollutant in the water body within the assessment unit. If multiple monitoring sections are involved, the average value of each section is taken. The unit is mg / l. oi It represents the maximum permissible concentration of the ith organic pollutant in the water body within the assessment unit, in mg / l; The calculation process of the organic pollutant risk status index is as follows: ; In the formula, R o Indicates the comprehensive risk status of organic pollutants; C oi It represents the concentration of the ith organic pollutant in the water body within the assessment unit. If multiple monitoring sections are involved, the average value of each section is taken. The unit is mg / l. oi It represents the maximum permissible concentration of the ith organic pollutant in the water body within the assessment unit, in mg / l; Step S5: Evaluate the water environment quality based on the classification result, the smaller the grade, the better the water environment quality.

2. The water environment quality evaluation method based on physical and chemical indicators according to claim 1 is characterized in that: In step S1, water body types include lakes, reservoirs, rivers and estuaries.

3. The water environment quality evaluation method based on physical and chemical indicators according to claim 2 is characterized in that: In step S2, the mandatory indicators include at least comprehensive pollution status indicators, comprehensive nutritional status indicators and comprehensive pollution status indicators, and the reference indicators include at least heavy metal risk status indicators and organic pollutant risk status indicators, wherein the reference indicators are screened and determined based on the degree of water pollution and management needs; other pollutants except the mandatory indicators, if the concentration exceeds the surface water quality standard limit, or there is a risk for pollutants that are not included in the management, will be listed as reference indicators.

4. The water environment quality evaluation method based on physical and chemical indicators according to claim 3 is characterized by: The mandatory indicators for lakes and reservoirs include comprehensive pollution status indicators and comprehensive nutrient status indicators; the mandatory indicators for rivers and estuaries include comprehensive pollution status indicators; the reference indicators for lakes, reservoirs, rivers and estuaries include heavy metal risk status indicators and organic pollutant risk status indicators.

5. The water environment quality evaluation method based on physical and chemical indicators according to claim 1 is characterized in that: In step S5, level conditions are set for the comprehensive pollution status index, comprehensive nutritional status index, heavy metal risk status index and organic pollutant risk status respectively. Under the level conditions: the calculation results of the comprehensive pollution status index meet 95≤WQI≤100, the calculation results of the comprehensive nutritional status index meet TLI(∑)<30, and the calculation results of the heavy metal risk status index meet R M <0.3, the calculation results of the organic pollutant risk status index meet R O <0.3; Under level 2: the calculation result of the comprehensive pollution status index satisfies 80≤WQI<95, the calculation result of the comprehensive nutrition status index satisfies 30≤TLI(∑)≤50, and the calculation result of the heavy metal risk status index satisfies 0.3≤R M <0.7, the calculation result of the organic pollutant risk status index satisfies 0.3≤R o <0.7; Under level three conditions: the calculation results of the comprehensive pollution status index meet 65≤WQI<80, the calculation results of the nutrient status index meet 50<TLI(∑)≤60, and the calculation results of the heavy metal risk status index meet 0.7≤R M <1, the calculation result of the organic pollutant risk status index satisfies 0.7≤R o <1; Under level 4: the calculation result of the comprehensive pollution status index satisfies 45≤WQI<65; The calculation results of the nutritional status index meet 60< TLI(∑)≤70, and the calculation results of the heavy metal risk status index meet 1≤R M <1.5, the calculation result of the organic pollutant risk status index satisfies 1≤R o <1.5; Under level five conditions: the calculation result of the comprehensive pollution status index satisfies 0≤WQI<45.

6. The water environment quality evaluation method based on physical and chemical indicators according to claim 5 is characterized by: In step S5, the water quality evaluation grade classification process is as follows: 1) When the calculation results of the comprehensive pollution status index, the comprehensive nutrient status index, the heavy metal risk status index, and the organic pollutant risk status index all meet the corresponding level conditions one, the water quality evaluation level is determined to be the first level; 2) When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the second level condition, the water quality evaluation level is determined to be the second level; Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition one, and any one or two of the three indicators, including the calculation result of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index, meet the corresponding level condition two, the water quality evaluation level is determined to be the second level; Alternatively, when the calculation result of the comprehensive pollution status index meets the second level condition, and any one of the calculation results of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index meets the corresponding second level condition, and the calculation results of the remaining indicators at least meet the third level condition, then the water quality evaluation level is determined to be the second level; Alternatively, when the calculation results of the comprehensive pollution status index meet the second level condition, and the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the third level condition respectively, the water quality evaluation level is determined to be the second level; 3) When the calculation results of the comprehensive pollution status index, the comprehensive nutrient status index, the heavy metal risk status index, and the organic pollutant risk status index all meet the corresponding level conditions three, the water quality evaluation level is determined to be the third level; Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition one, and at least two of the three indicators, namely, the calculation result of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index, meet the corresponding level condition four, the water quality evaluation level is determined to be the third level; Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition 2, and at least one of the calculation results of the comprehensive nutrient status index, the calculation result of the heavy metal risk status index, and the calculation result of the organic pollutant risk status index meets the corresponding level condition 4, the water quality evaluation level is determined to be the third level; 4) When the calculation result of the comprehensive pollution status index meets the fourth level condition, the water quality evaluation level is determined to be the fourth level regardless of whether the other indicators meet the corresponding second or third level conditions; 5) When the calculation results of the comprehensive pollution status index, the calculation results of the comprehensive nutrient status index, the calculation results of the heavy metal risk status index, and the calculation results of the organic pollutant risk status index all meet the corresponding level conditions 4, the water quality evaluation level is determined to be the fifth level; Alternatively, when the calculation result of the comprehensive pollution status index meets the level condition five, the water quality evaluation level is determined to be the fifth level.

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