This standard specifies the detailed principles for the design of sampling schemes, sampling techniques, sample storage and handling for lakes and reservoirs. This standard does not include sampling for microbiological testing. This standard applies to lakes and reservoirs. GB/T 14581-1993 Technical Guidelines for Sampling of Water Quality Lakes and Reservoirs GB/T14581-1993 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Guidance on sampling techniques for lakes and reservoirs
Water quality-Guldance on sampling techniques from lakes, natural and man-made
This standard is the fourth part of the water quality sampling standard, G/T 14581-93
This standard refers to the international standard IS056t67-4: 1987 "Water Quality Sampling Part 4: Guidance on Sampling of Lakes and Reservoirs". 1 Subject content and scope of application
This standard specifies the detailed principles of sampling scheme design, sampling techniques, sample preservation and processing for lakes and reservoirs. This standard does not include sampling for microbiological testing. This standard is applicable to lakes and reservoirs. The following three aspects are required: 1.1 Water quality characteristic detection
Long-term quality detection of water bodies. Used to investigate and study the water quality status and development trend of lakes and reservoirs. 1.2 Water quality control detection
Long-term water quality detection is carried out at one or several designated sampling points in the water body. 1.3 Detection of special conditions
Detection of pollution when there are disturbances, deaths or other abnormal phenomena (blooms, colors, etc.) of biological species or populations. 2 References
GB6816 Water Quality Vocabulary Part 1 and Part 2 GB12997 Technical Specifications for Design of Water Quality Sampling Programs GH12998 Technical Guidance for Water Quality Sampling
GB12999 Technical Specifications for Storage and Management of Water Quality Sampling Samples 3 Definitions
3.1 Point water sample
A sample collected randomly from a water body without reversal in time and place. 3.2 Depth sample group
A group of samples collected at different depths at a specific location in a water body. 3.3 Plane sample group
A group of samples collected at different locations at a specific depth in a water body. 3.4 Comprehensive sample
3.4.1 Depth comprehensive sample
A sample obtained by mixing two or more samples collected continuously or discontinuously from a specific location in a water body on the same vertical line, from the surface to the sediment layer, or other specified depths. 3.4.2 Plane comprehensive
Approved by the State Environmental Protection Agency on August 14, 1993 and implemented on April 1, 1994
GB/T 14581--93
A water sample collected from different locations at a specific depth of a water body, and mixed. 4 Sampling equipment
4.1 Material
The material of the sampling container (such as stainless steel or plastic) should not react with water as much as possible. The material of the container should be inert in terms of chemical and biological aspects to minimize the reaction between the sample components and the container. Light may affect the organisms in the water sample and thus produce undesirable chemical reactions, which should be considered when selecting materials. 4.2 Types of equipment
4.2.1 Surface and surface samplers Open samplers are open containers used to collect water from the stratum and near the bottom. It is not possible to collect a sample with good surface and reproducibility when floating materials are present.
4.2.2 Closed tube samplers
Closed tube samplers are hollow bodies equipped with valves or gates that can be operated remotely or opened and closed automatically. They can be quickly closed when a predetermined water depth is reached. They are used to collect fixed-point water samples or a group of samples, or deep comprehensive samples. The sampler should be equipped with a venting device to collect water samples that are not mixed with air (or gas) accumulated in the tube. When sampling near the bottom, be careful not to stir the interface between water and sediment. Some samplers have mechanical or remote release devices that automatically close when they come into contact with sediment. This type of sampler is particularly suitable for collecting water samples close to the sediment interface. 4.2.3 Water-inserting device
The water-pumping device should be of both hand-seeding and electric types. When in use, use an electric cable to pull them to the required depth or fix them at the sampling position.
The results may be different when collecting biological samples with a water pump and a closed-tube sampler. The type of pump, pump speed, water pressure, and water flow rate in the pipe will affect the collection of samples. Different biological species may also respond differently to sampling with different types of pumps. 5 Sampling steps
5.1 Sampling locationWww.bzxZ.net
The selection of sampling point layout should be carried out through a detailed preliminary investigation in a larger sampling range, and statistical techniques should be used to reasonably determine it based on sufficient information.
The layout of sampling points should fully consider the following factors: 3. Hydrodynamic conditions of lake water bodies;
Tidal reservoir area, lake basin morphology:
c. Recharge conditions, mountains and water intake;
d. Location and scale of sewage discharge facilities;
e. Circulation and migration and transformation of pollutants in water bodies: f. Differences between lakes and reservoirs.
If it is necessary to evaluate the impact of lake (reservoir) flow, a special measurement plan must be adopted. 5.1.1 Horizontal distribution of sampling points
5.1.1.1 Sampling points for water quality characteristics
Many tidal flats and waterways have complex coastlines or several directional water surfaces. The irregular shapes may cause obvious differences in water quality characteristics in the horizontal direction. In order to evaluate the unevenness of water quality, it is necessary to set up several sampling points and conduct a preliminary investigation on their traces. The collected data can effectively determine the required sampling points. When the water quality characteristics of lakes and reservoirs do not show obvious differences in the horizontal direction, it is allowed to set up only one sampling point above the deepest level of the water. The sampling point should be clearly marked. The sampling mark can be determined by buoy method, sextant method, shore mark method or radio navigation positioning. 5.1.1.2 Sampling points for water quality control
The sampling points should be located near the water intake and the entrance of the main water source. 5.1.1.3 Sampling points for special circumstances
GB/T 14581 :93
At the location where the abnormal phenomenon is observed, sampling is usually carried out once or several times. The sampling location should be clearly indicated in the report, and a graphical method can be used if possible.
5.1.2 Vertical distribution of sampling points
Due to the stratification phenomenon, the water quality of lakes and reservoirs may be greatly uneven along the water depth direction. The source is the influence of the white water surface (water quality changes caused by photosynthesis and water temperature changes in the light zone) and sediments (dissolution of substances in the sediment layer). In addition, the sedimentation of suspended matter may also cause vertical unevenness of water quality. Large differences in water quality are often observed in the thermocline layer. Based on the above situation, when sampling in non-uniform water bodies, the distance between the depths of the sampling points should be shortened as much as possible. The appropriate layout of the sampling layers depends on the required information and the local environment. Preliminary investigations can use detectors (such as measuring temperature , dissolved oxygen, pH, conductivity, turbidity and fluorescence of leaf cords). The detector can provide continuous or short interval detection. Staggered sampling depths can show all vertical heterogeneity. Once the sampling plan is determined, it must be strictly implemented. If the plan is changed during the sampling process, the measured data will lack comparability. When the water quality of lakes and reservoirs varies greatly along the depth direction, a group of samplers can be used to sample simultaneously. 5.2 Sampling time and sampling time selection
The water quality of lakes and reservoirs varies seasonally, and the sampling frequency depends on the status and characteristics of water quality changes. Usually, for long-term water quality characteristics detection, a reasonable monitoring frequency can be selected according to the research and requirements. The interval between fixed-point water samples is allowed to be one month: for permanent quality control detection, the sampling time interval can be shortened to one week. If the water quality changes significantly, sampling is required every day, or even continuous sampling.
In addition, for water quality that often changes significantly at a certain moment in the day, and the detection of the change trend is very important, sampling should be carried out at the same time every day to reduce the impact of time factors on water quality detection. If the intraday changes are of special significance, it is recommended to collect samples every 2~3 hours.
5.3 Selection of sampling method
The selection of sampling method depends on the daily sampling specified in the sampling plan. Sampling for special circumstances or sampling for the purpose of water quality control is usually done by collecting fixed-point water samples. For example, to measure water quality characteristics, a group of fixed-point water samples can be used. Composite samples can also be used. It is too expensive to analyze a group of fixed-point water samples separately. In order to reduce the analysis cost, fixed-point water samples are often mixed and analyzed. Composite samples can only represent the average value, and cannot show the conditions and quality change range under extreme conditions. A more reasonable way is to take a composite sample in a short time interval and a group of fixed-point water samples in a longer time interval, and combine the two sampling methods. 5.4 Transportation, Fixation and Storage of Samples
Due to gas exchange, chemical reaction and biological metabolism, water quality changes very quickly. Therefore, the sample container sent to the laboratory should be sealed, shockproof, and avoid sunlight and overheating. When the sample cannot be analyzed quickly, the sample needs to be fixed and well preserved. For short-term storage, it can be refrigerated at 2-5°C.For long-term storage, the sample should be frozen to -20°C. During the freezing process, some components may be concentrated in the center of the frozen sample. Therefore, when using frozen samples, the sample should be completely thawed. It can also be preserved by adding chemicals, but it should be noted that the selected preservation method cannot interfere with the subsequent sample inspection or affect the test results. All sample processing and preservation steps should be recorded in the on-site measurement record. Measure and record the on-site temperature. Some physical parameters such as pI value should be measured on-site or as soon as possible.
6 Safety protection
In order to ensure the safety of staff and instruments, meteorological conditions must be considered; when sampling on populated water bodies, the boats used must be sturdy, and lifebuoys and life ropes must be used; before sampling in water bodies covered with ice, the location and range of the thin ice layer must be carefully checked. It is necessary to select a location that can be easily and frequently sampled under any climatic conditions, and avoid sampling from dangerous locations such as unsafe lake shores as much as possible. 7 Identification and recording of samples
The situation of each sampling point should be recorded. During long-term sampling, when conditions remain unchanged, it is not necessary to repeat the description every time sampling is performed. The instrument should describe the tests conducted on site and the conditions that are prone to change, such as climatic conditions and abnormal conditions observed. GE/T1458193
When sampling is performed for a special reason, detailed information should be given, including the reason for sampling and the preservation method adopted. The report should include a schematic diagram. See Appendix A for an example of a report.
Name of lake and reservoir:
Reason for sampling:
Characteristics of sampling point:
When sampling: Start
Sampling method:
Depth sample group: Quantity
Depth comprehensive sample: Observations at
Sampling point:
Presence or absence of ice layer
Water color
Aquatic plants
Floating objects
Weather conditions in the region,
Cloud City (%)| |tt||Remarks:
GB/T14581--93
Appendix A
Lake and reservoir sampling report
(Supplement)
Location of sampling points:
The depths are
Date:
m
Recorder
Sampling point
Sampling time
Sample processing and preservation:
CB/T 14581-- 93
Appendix B
On-site measurement record
(Supplement)
Measurer
Recorder
Transparency
Additional remarks:
GB/T 14581: 93
This standard was proposed by the Department of Science and Technology Standards of the State Environmental Protection Administration. This standard was drafted by the China National Environmental Monitoring Center. The main drafters of this standard are Liu Zhenzhuang and Chen Pei: This standard is entrusted to the China National Environmental Monitoring Center for interpretation.
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