Surface water sampling

01 The sampling section should have obvious markers, and the sampling personnel shall not change the sampling location without authorization. When sampling, GPS positioning or fixed markers should be used to determine the sampling location to ensure the accuracy of the sampling point.

02 On-site monitoring is recommended for items such as water temperature, pH value, dissolved oxygen, conductivity, transparency, and salinity.

03 For river cross-sections, you can use rangefinders and depth meters to measure the width and depth of the river; for lake and reservoir locations, you can use depth meters to measure the depth of the lake and reservoir. Then, in accordance with the requirements of HJ/T91, it is determined that the number of vertical lines and the number of sampling points on the vertical lines need to be collected, and water samples are collected separately.

04 When sampling, do not disturb the bottom sediment.

05 If the water sample contains sedimentary solids (such as sediment, etc.), it should be separated and removed.

The separation method is: shake the collected water sample and pour it into a cylindrical glass container (such as a 1~2L graduated cylinder), let it stand for 30 minutes, and transfer the water sample that does not contain sedimentary solids but contains suspended solids into the container. Sample container and add preservative. Except water samples for measuring water temperature, pH value, dissolved oxygen, conductivity, total suspended solids and oils.

06 When determining the chemical oxygen demand, permanganate index, chlorophyll a, total nitrogen, and total phosphorus of the lake and reservoir water, the water sample is allowed to stand for 30 minutes. The water tip should be inserted to a position below 50mm from the surface of the water sample, and a preservative should be added for storage.

07 Water samples for measuring Five-day Biochemical Oxygen Demand should be sampled separately and dry sample bottles should be used. Before sampling, do not rinse the sample bottle with water sample. Collect the water sample in a brown glass bottle. The water sample must be filled with no space on the top.

08 For the determination of sulfide water samples, separate samples should be taken, first add an appropriate amount of zinc acetate-sodium acetate solution, and then add sodium hydroxide solution when the water is released to the bottleneck until a white precipitate just appears , Fill the container with water sample and leave no air under the stopper.

09 For the determination of petroleum water samples, separate samples should be taken and dry sample bottles should be used. Before sampling, do not rinse the sample bottle with water sample. Before sampling, destroy the oil film that may exist, collect a columnar water sample from the water surface to 300mm, and all the collected water samples are used for determination.

10 For the determination of Chlorophyll a water sample, separate samples should be taken and dry sample bottles should be used. Before sampling, do not rinse the sample bottle with water sample. If the water sample contains sedimentary solids (such as silt, etc.), use aluminum foil to protect from light and settle for 30 minutes. Take the upper water sample and transfer it to a brown hard glass bottle.

11 Determine the water samples of heavy metals copper, lead, zinc, cadmium, iron and manganese in the sea control section monitoring project. The collected water samples are not subject to natural settlement and are immediately on site (not available for ship sampling Except for filtering conditions) Collect after filtration treatment with 0.45μm microporous membrane.

12 Requirements for the collection of bacteriological samples: When collecting samples, the sampling bottles shall not be washed with the samples, and the samples shall be collected in sterile sampling bottles. The sampling volume of clean water bodies shall not be less than 400mL, and the sampling volume of other water bodies shall not be less than 100mL.

When collecting surface water samples from rivers, lakes, reservoirs, etc., you can hold the lower part of the bottle and directly insert the sample bottle with stopper into the water, about 10~15cm away from the water surface, with the mouth of the bottle facing the direction of the water flow, pull out the stopper to fill the sample The bottle is then covered with a stopper, and the sampling bottle is taken out of the water. If there is no water flow, hold the bottle and push it forward horizontally. The sampling volume is generally about 80% of the capacity of the sampling bottle. After the sample is collected, quickly tie up the sterile wrapping paper.

When collecting surface water, wastewater samples and samples at a certain depth, sterilized special sampling devices can also be used for sampling.

13 When collecting samples of volatile organic compounds, it is not advisable to wash with water samples. The water samples should overflow in the sample bottle without leaving space. When sampling, try to avoid or reduce the sample in the air. Exposure. All samples were collected in parallel double samples.

14 When sampling with a vessel, the sampling vessel should be located in the downstream direction and perform countercurrent sampling to avoid disturbing the bottom sediments and causing water sample pollution. The sampling personnel should take samples at the front of the ship and try to keep the sampler away from the hull.

15 When stratified sampling is carried out at the same sampling point, it should be carried out from top to bottom to avoid mixing of water bodies at different levels.

16 When measuring dissolved oxygen, five-day biochemical oxygen demand and organic pollutants, etc., the water sample must be filled with the container to avoid aeration of the water sample or the presence of bubbles in the bottle.

17 Separate samples should be taken for the determination of oils, five-day biochemical oxygen demand, dissolved oxygen, sulfide, residual chlorine, fecal coliforms, suspended solids, and radioactivity. At the same sampling point, priority is given to collecting water samples from the bacteria monitoring project.

18 When measuring the pH value and dissolved oxygen of lakes and reservoirs on site, the depth of the measured water body, measurement time, water temperature and weather conditions, etc. should be recorded in order to explain the possible pH value and dissolved oxygen abnormal situation.

19 The monitoring section affected by the tide collects water samples at the rising and falling tide levels. In order to ensure the safety of sampling, the sampling should generally be completed at the time of the rising and falling tides during the day according to the change of the tide. High tide water samples should be taken at the section when the water surface is rising and normal, and low tide water samples should be taken when the water surface is receding.

20 For each batch of water samples, some items should be selected to add on-site blank samples, and the samples should be sent to the laboratory for analysis.

21 The "Water Quality Sampling Record Form" must be carefully filled in when sampling. Use a signature pen to record on the spot with correct and clear writing. The project is complete.

22 Before the end of sampling, the sampling plan, records and water samples should be checked. If there are errors or omissions, they should be re-collected or re-collected immediately.

23 If the water body at the sampling site is very uneven and representative samples cannot be collected, the unevenness and actual sampling conditions should be recorded in detail for the reference of those who use the data.

Groundwater sampling

01 Groundwater quality monitoring usually collects instantaneous water samples.

02 For well water whose water level needs to be measured, the groundwater level should be measured before sampling.

03 Water samples collected from wells must be fully swabbed. The amount of water swabbed should not be less than twice the volume of the water in the well. The sampling depth should be 0.5m below the groundwater surface to ensure that the water sample can represent the quality of the groundwater.

04 For closed production wells, samples can be taken from the discharge valve of the outlet pipe of the pump house when pumping. The water in the pumping pipe should be drained before sampling.

05 For self-spraying spring water, sampling can be done at the center of the water stream at the gushing. When collecting water that does not come from the fountain, the water stagnated in the pumping pipe is drawn out, and sampling is carried out after the new water is replaced.

06 Before sampling, in addition to the five-day biochemical oxygen demand, organic matter and bacteria monitoring items, first wash the sampler and water sample container with sampling water 2 to 3 times.

07 Water samples for the determination of dissolved oxygen, five-day biochemical oxygen demand and volatile and semi-volatile organic pollutants. When sampling, the water sample must be filled with the container without leaving a gap in the upper part. However, the container should not be filled with samples that are to be frozen, otherwise the container will rupture due to the expansion of the volume of the water sample after freezing. The water sample for measuring dissolved oxygen should be fixed on site after collection, and the bottle should be sealed with water after the bottle stopper is closed.

08 The water samples for the five-day biochemical oxygen demand, sulfide, petroleum, heavy metals, bacteria, radioactivity and other items should be sampled separately. Keep the water and let it go clean.

09 After collecting the water sample, immediately add the preservative as required, tightly cap and seal the water sample container, and affix the label. The label design can be based on the specific conditions of each station, and generally should include the monitoring well number, sampling date and time , Monitoring items, samplers, etc.

10 Before the end of sampling, the sampling plan, sampling records and water samples should be checked. If there is an error or missed sampling, it should be re-collected or supplemented immediately

Precipitation sampling

01 It is very difficult to accurately collect precipitation samples. Before precipitation, the sampler must be covered and opened only after precipitation actually occurs. Take the whole process of water samples for each precipitation (from the beginning to the end of precipitation). When collecting samples, avoid sources of pollution and sand, and there should be no tall trees or buildings that block rain and snow around the sampler in order to obtain accurate results.

02 The relative height of the sampler should be above 1.2m.

03 Every time rain (snow) begins, immediately place the spare sampler on the stand at the predetermined sampling point, open the lid to start sampling, and record the start sampling time. Do not open the lid to take samples before precipitation to prevent the impact of settlement.

04 Take samples of the whole process of each precipitation (from the beginning to the end of precipitation). If there are several precipitation processes in a day, they can be combined into one sample for measurement. In case of continuous rainfall for several days, the precipitation from 8:00 am to 8:00 am of the next day can be collected, that is, a 24-hour precipitation sample is used as a sample for measurement.

05 The collected samples should be moved into clean and dry polyethylene plastic bottles, sealed and stored. Label and number the sample bottle, and record the sampling location, date, start and end time, and precipitation.

Wastewater sampling

01 Before sampling, it is necessary to understand the production and treatment process, discharge rules and treatment measures related to the discharge of wastewater in order to formulate a sampling plan, determine the existence of interference factors and take necessary pretreatment measures.

02 In the sampling of wastewater, special attention should be paid to the representativeness of the sample. Industrial wastewater should be sampled at the discharge outlet of the workshop or workshop treatment facility for the first-class pollutants, and the second-class pollutants and other organic items should be sampled at the factory's general discharge outlet. The domestic sewage is sampled before the sewage enters the pipe network, and the hospital sewage has a sampling point at its discharge outlet. Sampling point--Once determined, it cannot be changed at will.

03 The actual sampling position should be at the center of the sampling section. When the water depth is greater than 1m, sampling should be done at 1/4 depth below the surface; when the water depth is less than or equal to 1m, sampling should be done at 1/2 of the water depth.

04 When sampling, care should be taken to remove debris, garbage and other floating objects on the water surface.

05 When collecting wastewater samples, it is recommended to measure the flow rate at the same time as the basis for determining the composition ratio of the mixed sample and the calculation of the sewage volume.

06 The wastewater samples collected are mainly instantaneous samples and proportional mixed samples. The production process of some sewage units is continuous and stable, and the instantaneous sample has a good representativeness, so the instantaneous sampling method can be used. For pollution sources with sewage treatment facilities and normal operation or with a regulating tank, the wastewater is discharged steadily, and instantaneous wastewater samples can also be collected during monitoring. The unstable discharge of wastewater should be sampled in time units to form a mixed sample for analysis. When the change in wastewater flow rate is less than 20% and the pollutant concentration changes little over time, equal volume water samples are collected at equal time intervals and mixed.

07 Automatic sampling is carried out with an automatic sampler, with time proportional sampling and flow proportional sampling. When the sewage discharge volume is relatively stable, sampling in an equal proportion of time can be used, otherwise, sampling in an equal proportion of flow must be used.

08 For monitoring items that are greatly affected by suspended solids, the automatic sampling should be 5cm below the water surface of the sewage drain (road, ditch), 1/2 of the side of the canal (road, ditch) and the center of the waterway; manual sampling Sampling is the same as oil sampling, and a uniform water sample containing suspended solids should be collected.

09 Sewage monitoring items have different requirements according to the type of industry. When collecting samples in time units, measure pH, chemical oxygen demand, five-day biochemical oxygen demand, dissolved oxygen, sulfide, oil, organic matter, residual chlorine, fecal and large intestine, suspended matter, radioactivity, etc. , Cannot be mixed, can only be sampled separately.

10 For different monitoring items, the material of the container should be selected, the preservative added, the amount and storage period, the volume of the water sample that should be collected, and the washing method of the container.

11 The composition of wastewater samples is often quite complex, and its stability is usually worse than that of surface water, so try to determine it as soon as possible.

12 When using the sample container for direct sampling, it must be rinsed with water sample three times before sampling, except for special items. But when there is oil slick on the water, the oil production container cannot be washed.

13 The water samples used to determine suspended solids, five-day biochemical oxygen demand, sulfides, oils, and residual chlorine must be separately sampled at a constant volume and all used for determination.

14 When using a special dedicated sampler (such as an oil sampler), sampling should be done in accordance with the method of use of the sampler.

15 When sampling, the "Sampling Record Form" should be filled in carefully, and the following content should be included in the form: name of pollution source, monitoring purpose, monitoring item, sampling point, sampling time, sample number, sewage nature, sewage flow, name of the person who sampled it And other related matters.

16 For the collection requirements and other precautions of organic matter, bacteriology and other samples, please refer to surface water.