Double-traceability-technology-coupled aquaculture pollution key source area identification method

Abstract

The invention provides an aquaculture pollution key source area identification method based on double traceability technology coupling, and belongs to the technical field of water body pollution traceability. The source intensity accounting result and the water quality fluorescence fingerprint similarity analysis result are subjected to overlay analysis, and the aquaculture pollution key source area can be identified; according to the method, method guidance is provided for accurate identification of the aquaculture pollution key source area in an intensive aquaculture area, so that accurate management and control and pollution treatment can be carried out on the aquaculture pollution key source area.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution source tracing, and particularly relates to a method for identifying key source areas of aquaculture pollution by coupling dual source tracing technologies. Background Art

[0002] Aquaculture pollution is one of the important sources of agricultural non-point source pollution. In the southern water network area, the aquaculture industry is developed, the aquaculture areas are relatively concentrated, and the discharge of aquaculture tail water is the main reason for the water pollution of the surrounding rivers.

[0003] Due to the wide distribution of aquaculture pollution, the lack of regularity in tail water discharge, and the large instantaneous discharge volume, if comprehensive prevention and control of aquaculture pollution and tail water treatment are carried out, it will lead to high input costs and great implementation difficulties, but the work progress and effectiveness are difficult to guarantee. Therefore, it is necessary to study and establish a method for identifying key source areas of aquaculture pollution. Taking effective measures to carry out pollution prevention and control and tail water treatment for the identified key source areas is of great significance for reducing input costs and improving treatment effectiveness.

[0004] The existing pollution source area identification technologies are basically designed for agricultural non-point source or non-point source pollution, and no identification method specifically for the key source areas of aquaculture pollution has been found yet. Summary of the Invention

[0005] In order to achieve the above object, the key source area identification of the present invention adopts the following technical solution:

[0006] The present invention provides a method for identifying key source areas of aquaculture pollution by coupling dual source tracing technologies, including the following steps:

[0007] Dividing the target area to be identified into multiple target control units; the target area to be identified includes ponds, main streams, and tributaries; each target control unit includes pond water and tributaries;

[0008] According to the total emissions of aquaculture pollutants in the target control unit, screening at least one target control unit as the first pollution source area; wherein, in the first pollution source area, the total emissions of pollutants in each target control unit are greater than or equal to the median of the total emissions of pollutants in all target control units;

[0009] Setting multiple monitoring points in the target area to be identified, the monitoring points include the first monitoring points set on the tributaries inside each target control unit, the second monitoring points set upstream of the main stream outside each target control unit, the third monitoring points set downstream of the main stream outside each target control unit, and the fourth monitoring points located in the pond water;

[0010] For each target control unit, conduct water quality fluorescence fingerprint tracing on the water body at the monitoring point, calculate the total pollution contribution difference value of the first monitoring point, the second monitoring point, and the fourth monitoring point of the target control unit to the water quality fluorescence fingerprint of the third monitoring point, and screen out the target control units with the total pollution contribution difference value exceeding the difference threshold as the second pollution source areas;

[0011] Take the target control units that coexist in the first pollution source area and the second pollution source area as the key pollution source areas.

[0012] Note: The above method can more accurately and comprehensively identify the key source areas of aquaculture pollution, provide a scientific basis for pollution control and environmental management, and at the same time improve the reliability and efficiency of pollution source identification through the combination of multi-point monitoring and dual tracing technology.

[0013] Furthermore, the calculation method of the total emissions of aquaculture pollutants is as follows:

[0014] The total emissions of pollutants is the sum of the emissions of each pollutant. The emissions of a pollutant is equal to the pollution discharge coefficient of the pollutant multiplied by the aquaculture production increase. The pollutants include total nitrogen, total phosphorus, ammonia nitrogen, and COD. The aquaculture production increase is equal to the total catch minus the fry input.

[0015] Note: The above method can quantify the specific pollution contribution of aquaculture activities to the environment, and ensure the accuracy and operability of emissions estimation by clarifying the calculation methods of pollutant types (total nitrogen, total phosphorus, ammonia nitrogen, COD) and aquaculture production increase.

[0016] Furthermore, the second monitoring point is located at the upstream of the main stream 200 m away from the boundary of the target control unit, and the third monitoring point is located at the downstream of the main stream 200 m away from the boundary of the target control unit.

[0017] Note: The setting of the above distance can ensure that the monitoring points can effectively capture the water quality changes inside and outside the target control unit, so as to more accurately evaluate the impact of the target control unit on the water quality of the main stream.

[0018] Furthermore, the calculation method of the total contribution difference value is as follows: First, calculate the water quality fluorescence fingerprint similarity of the first monitoring point, the second monitoring point, and the fourth monitoring point to the third monitoring point, and the water quality fluorescence fingerprint similarity of the fourth monitoring point to the first monitoring point respectively;

[0019] Take the water quality fluorescence fingerprint similarity with a water quality fluorescence fingerprint similarity greater than or equal to 0.60 as the data set. From the data set, take the water quality fluorescence fingerprint similarity R1 between the first monitoring point and the fourth monitoring point, the water quality fluorescence fingerprint similarity R2 between the fourth monitoring point and the third monitoring point, the water quality fluorescence fingerprint similarity R3 between the first monitoring point and the third monitoring point, and the water quality fluorescence fingerprint similarity R4 between the second monitoring point and the third monitoring point;

[0020] The calculation formula for the total contribution difference value C is: C = (R1 + R2) / 2 + (R3 - R4);

[0021] Note: The above method can quantify the comprehensive impact of different monitoring points on the water quality of the target monitoring point by calculating the similarity of the water quality fluorescence fingerprints between different monitoring points and calculating the total contribution difference value, objectively evaluate the relative contributions of various pollution sources, and thus provide a scientific basis for the accurate identification and effective management of pollution sources.

[0022] Further, the difference threshold is the median of the total contribution difference values of multiple target control units.

[0023] Note: The above difference threshold can ensure that the identified key pollution source areas are more representative, and thus provide more accurate guidance for pollution control and environmental management.

[0024] Further, the water quality fluorescence fingerprint is obtained by using three-dimensional fluorescence fingerprint spectrum analysis software.

[0025] Further, the method further includes:

[0026] Regarding the target control unit identified as only the second pollution source area as a secondary pollution source area;

[0027] Regarding the target control unit identified as only the first pollution source area as an ordinary pollution source area;

[0028] Regarding the target control unit where neither the first pollution source area nor the second pollution source area exists as a pollution-free area;

[0029] Among them, pollution control or pollution treatment needs to be carried out in the key pollution source areas, secondary pollution source areas, and ordinary pollution source areas.

[0030] Note: The above method can more accurately identify and classify areas with different pollution degrees, provide a basis for formulating differentiated pollution treatment strategies, ensure that the key pollution source areas are given priority and rapid restoration, and at the same time implement long-term restoration plans for the secondary pollution source areas, improving the efficiency and effect of overall environmental governance.

[0031] The present invention also provides an application of the above identification method, and the above method can be applied to aquaculture pollution control or pollution treatment.

[0032] Further, incorporate the key pollution source areas into the mandatory aquaculture pollution control areas, and adopt the method of source treatment and end ecological interception for aquaculture pollution treatment; incorporate the secondary pollution source areas into the mandatory aquaculture pollution control areas, and adopt the method of source treatment for aquaculture pollution treatment; for the ordinary pollution source areas, adopt the method of ecological restoration for pollution treatment.

[0033] Advantages of the present invention:

[0034] The present invention adopts a coupling method of strong source accounting for aquaculture pollution sources and dual-traceability technology of fluorescence fingerprints of polluted water body quality, and establishes a classification and identification method specifically for key source areas of aquaculture pollution, providing a method guidance for accurately identifying key source areas of aquaculture pollution in intensive aquaculture areas, so as to lay a working foundation for the next step of accurately controlling and treating pollution in key source areas of aquaculture pollution. Description of the drawings

[0035] Figure 1 is the flowchart of the method in the embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of the target area to be identified and the division of its target control units in the embodiment of the present invention;

[0037] Figure 3 is a distribution map of aquaculture pollution source areas initially identified based on strong source accounting in the embodiment of the present invention;

[0038] Figure 4 is a layout map of fluorescence fingerprint traceability monitoring points for the water quality of the target area to be identified in the embodiment of the present invention;

[0039] Figure 5 is a distribution map of aquaculture pollution source areas secondarily identified based on water quality fluorescence fingerprints in the embodiment of the present invention;

[0040] Figure 6 is a distribution map of aquaculture pollution source areas accurately identified based on strong source accounting and water quality fluorescence fingerprints in the embodiment of the present invention. Detailed implementation manners

[0041] If terms such as "first" and "second" are used in the description and claims of the present invention, they are used to distinguish different objects rather than to describe a specific order of the objects.

[0042] The "and / or" in the embodiments of the present invention represents the relationship between objects. For example, A and / or B may represent the following three situations: A exists alone, B exists alone, and A and B exist simultaneously.

[0043] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0044] In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" refers to two or more. For example, a plurality of target control units refers to two or more target control units.

[0045] To solve the problem in the background art of the lack of a method specifically for identifying key source areas of aquaculture pollution, an embodiment of the present invention provides a method and device for identifying key source areas of aquaculture pollution by coupling dual tracing technologies. By using pollutant emissions and water quality fluorescence fingerprint tracing to delimit pollution areas, the pollution situation of pollution source areas in water bodies can be identified.

[0046] As Figure 1 shown, a method for identifying key source areas of aquaculture pollution by coupling dual tracing technologies provided by an embodiment of the present invention includes S1 - S4;

[0047] S1. Divide the target area to be identified into a plurality of target control units; the target area to be identified includes aquaculture ponds, main streams and their tributaries; each target control unit includes pond water and tributaries.

[0048] Exemplarily, as Figure 2 shown, a concentrated aquaculture area of a certain river in a certain district of a certain city is used as the research basin of the embodiment. There are many aquaculture contiguous areas in the basin (a total of more than 13,000 mu), the aquaculture modes and varieties are relatively rich, and aquaculture is the main source of agricultural non - point source pollution in this basin.

[0049] According to the distribution of mountains, villages, farmlands, aquaculture ponds, river channels (sluices) and monitoring sections in the basin, topographic features, pollution source distribution, water system characteristics, etc., 7 target control units are divided on both sides of a certain river, numbered from ① to ⑦ from upstream to downstream.

[0050] S2. According to the total emissions of aquaculture pollutants in the target control unit, select at least one target control unit as the first pollution source area; among them, in the first pollution source area, the total emissions of pollutants in each target control unit are greater than or equal to the median of the total emissions of pollutants in all target control units.

[0051] The calculation method of the total emissions of aquaculture pollutants is:

[0052] The total emissions of pollutants is the sum of the emissions of each pollutant. The emissions of pollutants are equal to the pollution discharge coefficient of the pollutant multiplied by the aquaculture yield increase. The pollutants include total nitrogen, total phosphorus, ammonia nitrogen, and COD; the aquaculture yield increase is equal to the total catch minus the fry input. Query the aquaculture pollution discharge coefficients of 4 pollutants (total nitrogen, total phosphorus, ammonia nitrogen, COD) in the target area according to the "Emission Source Statistical Survey Production Pollution Discharge Accounting Method and Coefficient Manual".

[0053] Exemplarily, based on the basic data of aquaculture collected through on-site research and its pollutant discharge coefficients, the coefficient method is used to calculate the emissions (i.e., source strengths) of four pollutants (total nitrogen, total phosphorus, ammonia nitrogen, and COD) during the pond aquaculture process within each target control unit. The specific calculation results are shown in Table 1.

[0054] Table 1 Calculation results of source strengths of each target control unit in the study basin

[0055]

[0056]

[0057] The method for each target control unit in S2 to have a total pollutant emission greater than or equal to the median of the total pollutant emissions of all target control units is as follows: Sort the sum of the source strengths of the four pollutants within each target control unit, and separately select the target control units ranked in the top 50%. If the sum of the source strengths of the four pollutants (i.e., the total pollutant emission) of a certain target control unit is ranked in the top 50%, then this area is determined as the first pollution source area.

[0058] The aquaculture pollution source areas initially identified based on the source strength calculation results are: target control units ④③⑤ (the top 3 with darker colors). The sum of the source strengths of the four pollutants in each target control unit and the distribution of aquaculture pollution source areas are as Figure 3 shown.

[0059] S3. Set multiple monitoring points in the target area to be identified. The monitoring points include the first monitoring points set on the tributaries within each target control unit, the second monitoring points set on the upstream of the main stream outside each target control unit, the third monitoring points set on the downstream of the main stream outside each target control unit, and the fourth monitoring points located in the pond water.

[0060] The second monitoring point is located 200 m upstream of the main stream from the boundary of the target control unit, and the third monitoring point is located 200 m downstream of the main stream from the boundary of the target control unit.

[0061] Exemplarily, layout of traceability monitoring points and sampling and detection:

[0062] Select key points (i.e., monitoring points) in the aquaculture ponds, main streams, and tributaries of each target control unit to carry out traceability monitoring. A total of 48 sampling points are laid out, including 27 in aquaculture ponds, 14 in a certain main stream, and 7 in tributaries. The layout diagram of the points is shown in detail in Figure 4 ;

[0063] (3) Collect surface water samples at the above monitoring points. After filtering through a 0.45 μm polyethersulfone water-based filter membrane, refer to the method in the "Technical Guide for Pollution Source Tracing Monitoring Based on Water Quality Fluorescence Fingerprint (Trial)", and use a three-dimensional fluorescence spectrometer (excitation wavelength: 200 - 450 nm, emission wavelength: 200 - 600 nm) to measure the water quality fluorescence fingerprint of each water sample one by one with ultrapure water as the blank;

[0064] S4. For each target control unit, conduct water quality fluorescence fingerprint tracing on the water body at the monitoring point, calculate the total pollution contribution difference value of the first monitoring point, the second monitoring point, and the fourth monitoring point to the water quality fluorescence fingerprint of the third monitoring point in the target control unit, and screen out the target control units with the total pollution contribution difference value exceeding the difference threshold as the second pollution source area;

[0065] The calculation method of the total contribution difference value is as follows: First, calculate the water quality fluorescence fingerprint similarity of the first monitoring point, the second monitoring point, and the fourth monitoring point to the third monitoring point respectively, and the water quality fluorescence fingerprint similarity of the fourth monitoring point to the first monitoring point;

[0066] Take the water quality fluorescence fingerprint similarity greater than or equal to 0.60 as the data set; from the data set, take the water quality fluorescence fingerprint similarity R1 between the first monitoring point and the fourth monitoring point, the water quality fluorescence fingerprint similarity R2 between the fourth monitoring point and the third monitoring point, the water quality fluorescence fingerprint similarity R3 between the first monitoring point and the third monitoring point, and the water quality fluorescence fingerprint similarity R4 between the second monitoring point and the third monitoring point;

[0067] The calculation formula for the total contribution difference value C is: C = (R1 + R2) / 2 + (R3 - R4); where the larger the average value of R1 and R2, the more similar the water samples being compared, that is, the greater the pollution contribution of the pond water to the water quality of the downstream tributaries and the main stream; the positive difference between R3 and R4 indicates that the tributary of this target control unit makes a positive contribution to the water quality of the main stream, that is, it increases the pollution of the main stream, and the larger the difference between R3 and R4, the greater the contribution of this target control unit, and it is the main source of the pollution of the water quality of the main stream; when the difference between R3 and R4 is negative, it indicates that the tributary of this target control unit makes a negative contribution to the water quality of the main stream, that is, it dilutes the pollution of the main stream; the larger the value of C, the more similar the water samples being compared, that is, the greater the pollution contribution of the pond water and the tributary water to the water quality of the downstream main stream.

[0068] The difference threshold is the median of the total contribution difference values of multiple target control units (the above "screen out the target control units with the total pollution contribution difference value exceeding the difference threshold as the second pollution source area" means screening out the top 50% of the target control units arranged from large to small among multiple target control units); the water quality fluorescence fingerprint is obtained by using three-dimensional fluorescence fingerprint spectrum analysis software.

[0069] Exemplarily, according to the main aquaculture mode and main aquaculture varieties, select the top three aquaculture enterprises or farmers in each target control unit and in terms of the increased aquaculture production (total catch - fry input), and select one pond from each to collect pond water samples, and filter them on-site using a 0.45-μm polyethersulfone water-based filter membrane.

[0070] For each target control unit, use the river water downstream of the corresponding main stream of the target control unit as the target water sample, and use three-dimensional fluorescence fingerprint analysis software to compare the target water sample with the river water upstream of the main stream, tributary river water, pond water, and the fluorescence fingerprints of the water quality of the tributary river water and pond water samples one by one. Discard when the similarity R is less than 0.60; the specific calculation results are shown in Table 2;

[0071] Table 2 Analysis results of the similarity of typical samples in each target control unit

[0072]

[0073]

[0074] Note: " / " indicates that the similarity is less than 0.60, indicating that there is basically no correlation between the water samples, so they are discarded. At the same time, it results in a lack of subsequent calculation data, which is also represented by " / ".

[0075] The method for screening out the target control units with the total pollution contribution difference value exceeding the difference threshold as the second pollution source area in S4 is: based on the above calculation results, sort the magnitudes of the positive C values of each target control unit in the aquaculture pollution source area, and screen out the top 50% of the target control units, which are the second pollution source areas;

[0076] The aquaculture pollution source areas based on the secondary identification of water quality fluorescence fingerprints are: target control units ①⑥④ (the top 3 with darker colors). The analysis results of the similarity of typical water samples in each target control unit and the distribution of aquaculture pollution source areas are as Figure 5 shown.

[0077] S5. Take the target control units that exist in both the first pollution source area and the second pollution source area as the key pollution source areas;

[0078] Furthermore, take the target control units identified only in the second pollution source area as the secondary pollution source areas;

[0079] Take the target control units identified only in the first pollution source area as the ordinary pollution source areas;

[0080] Take the target control units that do not exist in either the first pollution source area or the second pollution source area as the pollution-free areas;

[0081] Among them, the key pollution source areas need to be quickly repaired, and the secondary pollution source areas need to be repaired in the long term;

[0082] Exemplarily, the aquaculture pollution source areas accurately identified based on source strength accounting and water quality fluorescence fingerprints are as follows Figure 6 shown: Target control unit ④ is the key pollution source area, target control units ① and ⑥ are secondary pollution source areas, target control units ③ and ⑤ are ordinary pollution source areas, and in addition, target control units ② and ⑦ are pollution-free aquaculture areas.

[0083] For the identified aquaculture pollution source areas classified at different levels, different pollution control or treatment methods can be adopted according to local conditions:

[0084] For the key pollution source areas, it is recommended to include them in the mandatory aquaculture pollution control area and adopt the method of "source treatment + end ecological interception" for aquaculture pollution treatment. Specifically, source treatment includes: requiring all large-scale pond aquaculture (for example, aquaculture water surface of 30 mu or more) and industrial aquaculture farms in this area to set up "three ponds and two dams", "constructed wetland" or "integrated sewage treatment equipment" to treat the aquaculture tail water before discharging it into the surrounding ditches or rivers; end ecological interception: select a suitable plot near the outlet of the regional tributary, and on the basis of making full use of the natural wetland of the river beach, artificially replant wetland plants suitable for local conditions (such as reed, pickerelweed, canna, Chinese lantern plant, etc.) to establish an end ecological interception system to further carry out ecological treatment on the regional effluent.

[0085] For the secondary pollution source areas, it is recommended to include them in the mandatory aquaculture pollution control area and adopt the method of "source treatment" for aquaculture pollution treatment: requiring all large-scale pond aquaculture (aquaculture water surface of 30 mu or more) and industrial aquaculture farms in this area to treat the aquaculture tail water through "three ponds and two dams", "constructed wetland" or "integrated sewage treatment equipment" and then discharge it into the surrounding ditches or rivers.

[0086] For the ordinary pollution source areas, they can be not included in the mandatory aquaculture pollution control area. It is recommended that large-scale pond aquaculture (aquaculture water surface of 30 mu or more) and industrial aquaculture farms treat the aquaculture tail water through "three ponds and two dams" or "constructed wetland" (that is, the way of ecological restoration) and then discharge it into the surrounding ditches or rivers.

[0087] For the pollution-free areas, it is recommended to keep the current situation.

[0088] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying key source areas of aquaculture pollution by coupling dual traceability technologies, characterized in that, Including: Dividing the target area to be identified into multiple target control units; the target area to be identified contains ponds, main streams, and tributaries; Each of the target control units contains pond water and tributaries; According to the total emissions of aquaculture pollutants in the target control unit, screening at least one target control unit as the first pollution source area; wherein, in the first pollution source area, the total pollutant emissions in each target control unit are greater than or equal to the median of the total pollutant emissions in all target control units; Setting multiple monitoring points in the target area to be identified, the monitoring points include the first monitoring point set on the tributary inside each target control unit, the second monitoring point set on the upstream of the main stream outside each target control unit, the third monitoring point set on the downstream of the main stream outside each target control unit, and the fourth monitoring point located in the pond water; For each target control unit, conduct water quality fluorescence fingerprint tracing on the water body of the monitoring points, calculate the total pollution contribution difference value of the water quality fluorescence fingerprints of the first monitoring point, the second monitoring point, and the fourth monitoring point to the third monitoring point, and screen out the target control units with the total pollution contribution difference value exceeding the difference threshold as the second pollution source area; Taking the target control units that coexist in the first pollution source area and the second pollution source area as the key pollution source area.

2. The method according to claim 1, wherein The calculation method of the total emissions of aquaculture pollutants is: The total pollutant emissions are the sum of the emissions of each pollutant, and the pollutant emissions are equal to the pollutant discharge coefficient multiplied by the aquaculture production increase; the pollutants include total nitrogen, total phosphorus, ammonia nitrogen, and COD; the aquaculture production increase is equal to the total catch minus the fry input.

3. The method according to claim 1, wherein The second monitoring point is located 200m upstream of the main stream from the boundary of the target control unit, and the third monitoring point is located 200m downstream of the main stream from the boundary of the target control unit.

4. The method according to claim 1, characterized in that, The calculation method of the total contribution difference value is: First, calculate the water quality fluorescence fingerprint similarity of the first monitoring point, the second monitoring point, and the fourth monitoring point to the third monitoring point respectively, and the water quality fluorescence fingerprint similarity of the fourth monitoring point to the first monitoring point; Taking the water quality fluorescence fingerprint similarity greater than or equal to 0.60 as the data set; taking the water quality fluorescence fingerprint similarity R1 between the first monitoring point and the fourth monitoring point, the water quality fluorescence fingerprint similarity R2 between the fourth monitoring point and the third monitoring point, the water quality fluorescence fingerprint similarity R3 between the first monitoring point and the third monitoring point, and the water quality fluorescence fingerprint similarity R4 between the second monitoring point and the third monitoring point from the data set; The calculation formula of the total contribution difference value C is: C = (R1 + R2) / 2 + (R3 - R4).

5. The method according to claim 1, characterized in that, The difference threshold is the median of the total contribution difference values of multiple target control units.

6. The method according to claim 3, characterized in that, The water quality fluorescence fingerprint is obtained by using three-dimensional fluorescence fingerprint spectrum analysis software.

7. The method according to claim 1, wherein The method further includes: Taking the target control units identified only as the second pollution source area as the secondary pollution source area; Taking the target control units identified only as the first pollution source area as the ordinary pollution source area; Taking the target control units where neither the first pollution source area nor the second pollution source area exists as the pollution-free area; Among them, pollution control or pollution treatment needs to be carried out in the key pollution source areas, secondary pollution source areas, and ordinary pollution source areas.

8. Use of the method according to claim 7, characterized in that, The method can be applied to pollution control or pollution treatment in aquaculture.

9. The application according to claim 8, characterized in that, The key pollution source areas are included in the mandatory aquaculture pollution control areas, and pollution treatment in aquaculture is carried out by means of source treatment and end ecological interception; the secondary pollution source areas are included in the mandatory aquaculture pollution control areas, and pollution treatment in aquaculture is carried out by means of source treatment; for ordinary pollution source areas, pollution treatment is carried out by means of ecological restoration.

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