Procedural regulations regarding the enviroment quality monitoring of soil
Some standard content:
NY/T395—2000
According to the relevant provisions of the National Environmental Monitoring Management Regulations, the Agricultural Environmental Monitoring Regulations and the Basic Farmland Protection Regulations, in view of the fact that my country's agricultural environmental monitoring network has been established, in order to meet the needs of work, combined with the functional scope and monitoring capacity of my country's agricultural environmental monitoring, this standard has been specially formulated.
Appendix A of this standard is the standard.
This standard was proposed by the Science and Technology Education Department of the Ministry of Agriculture. The drafting units of this standard: the Ministry of Agriculture Environmental Monitoring Center, Hubei Provincial Agricultural Environmental Protection Station. The main drafters of this standard: Liu Suyun, Zhan Xinhua, Lin Kuangfei, Liu Fengzhi, Tao Zhan. 3
1 Scope
Agricultural Industry Standard of the People's Republic of China
Procedural regulations regarding theenvironment quality monitoring of soil NY/T 395-2000
This standard specifies the technical contents of sampling, analysis methods, quality control measures, mathematical statistics, results expression and data compilation for farmland soil environmental monitoring.
This standard is applicable to farmland soil environmental monitoring. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB8170—1987 Rules for rounding off values
GB/T14550—1993 Soil quality
Determination of 666 and DDT
Gas chromatography
GB15618--1995 Soil environmental quality standardGB/T 17134--1997
GB/T 17135—1997
GB/T 17136--1997
GB/T 17137—1997
GB/T 17138—1997
GB/T 17139
GB/T 17140-
GB/T 17141---1997
NY/T 52—1987
NY/T 53--1987
NY/T 85—1988
NY/T 88---1988
Soil quality
Soil quality
Soil quality
Soil quality
Soil quality
Soil quality
Soil quality
Soil quality
Determination of total arsenic
Determination of total arsenic
Determination of total mercury
Determination of total chromium
Silver diethyldithiocarbamate spectrophotometry Potassium borohydride-silver nitrate spectrophotometry
Cold atomic absorption spectrophotometry
Flame atomic absorption spectrophotometry
Flame atomic absorption spectrophotometry Absorption spectrophotometry
Determination of copper and zinc
Determination of nickel
Flame atomic absorption spectrophotometry
Determination of lead and
Determination of lead and cadmium
KI-MIBK extraction flame atomic absorption spectrophotometry graphite furnace atomic absorption spectrophotometry
Soil moisture determination method (formerly GB7172-1987) Soil total nitrogen determination method (semi-micro Kelvin method) (formerly G137173-1987) Soil organic matter determination method (formerly GB9834-1988) Soil total phosphorus determination method (formerly GB9837-1988) NY/T 148--1990
Method for determination of available boron in soil (formerly GB12298-1990) NY/T149-1990
Method for determination of available phosphorus in calcareous soil (formerly GB12297--1990) 3 Definitions
This standard adopts the following definitions.
3.1 Farmland soil
Soil in agricultural land used for growing various food crops, vegetables, fruits, fiber and sugar crops, oil crops, and agricultural forests, flowers, medicinal materials, forage and other things.
Approved by the Ministry of Agriculture of the People's Republic of China on August 30, 2000 and implemented on December 1, 2000
3.2 Regional soil background points
NY/T395-2000
Soil sample points in or near the survey area that are relatively unpolluted and have similar parent materials, soil types and farming history to the soil in the survey area.
3.3 Farmland soil monitoring points
Soil sampling points where pollutants generated by human activities enter the soil and accumulate to a certain extent, causing or suspected of causing the deterioration of soil environmental quality.
3.4 Farmland soil profile samples
According to the main characteristics of soil genesis, the entire profile is divided into different layers, and multiple samples are taken at each layer, and the soil samples of A, B, C layers or A, C layers are mixed in equal amounts. 3.5 Farmland soil mixed samples
Collect the tillage layer soil at several points around the tillage layer sampling point, and the soil samples after mixing are mixed. The number of points that make up the mixed sample should be 5~~20.
4 Farmland soil environmental quality monitoring sampling technology 4.1 On-site investigation and data collection before sampling
4.1.1 Regional natural environment characteristics: hydrology, meteorology, topography, vegetation, natural disasters, etc. 4.1.2 Land use status of agricultural production: types of crops, layout, area, yield, farming system, etc. 4.1.3 Regional soil fertility status: soil parent material, soil type, layer characteristics, texture, pH, Eh, exchange capacity, base saturation, soil fertility, etc.
4.1.4 Soil environmental pollution status: types and distribution of industrial pollution sources, types of pollutants and emission pathways and emission amounts, agricultural irrigation water pollution status, air pollution status, agricultural solid waste input, agricultural chemical input, natural pollution sources, etc. 4.1.5 Soil ecological environment status: current status of soil erosion, soil erosion type, distribution area, erosion modulus, swamping, brooding, salinization, acidification, etc.
4.1.6 Soil environmental background data: regional soil element background value, agricultural soil element background value. 4.1.7 Other relevant data and maps: overall land use plan, agricultural resource survey plan, administrative division map, soil type map, soil environmental quality map, etc.
4.2 Division of monitoring units
Farmland soil monitoring units are divided into basic units according to the ways in which soils accept pollutants. They are demarcated by local agricultural environmental monitoring departments based on actual conditions, taking into account factors such as soil type, crop type, farming system, commodity production base, category of protected area, and administrative division. The differences in the same unit should be minimized as much as possible. 4.2.1 Air pollution type soil monitoring unit
The pollutants in the soil mainly come from air pollution sediments. 4.2.2 Irrigation water pollution type soil monitoring unit The pollutants in the soil mainly come from agricultural irrigation water. 4.2.3 Solid waste pile pollution type soil monitoring unit The pollutants in the soil mainly come from concentrated solid waste. 4.2.4 Agricultural solid waste pollution type soil monitoring unit The pollutants in the soil mainly come from agricultural solid waste. 4.2.5 Agricultural chemical pollution type soil monitoring unit The pollutants in the soil mainly come from agricultural chemical substances such as pesticides, fertilizers, and growth hormones. 4.2.6 Comprehensive pollution soil monitoring unit
The pollutants in the soil mainly come from the above two or more pathways. 4.3 Layout of monitoring points
NY/T395--2000
4.3.1 Number of points
The number of points for soil monitoring should be determined based on the purpose of the survey, the accuracy of the survey and the environmental conditions of the survey area. It is generally required that each monitoring unit should have at least 3 points.
The number of sample points for legal arbitration investigation of soil pollution disputes should be large, and 1 to 5 sample points/hm can be used; the environmental quality monitoring of green food production areas shall be carried out in accordance with the provisions of the "Outline for the Current Evaluation of Environmental Quality in Green Food Production Areas". The general soil quality survey can be determined according to the actual situation on the premise of ensuring the representativeness of soil samples. 4.3.2 Principles and methods of site selection
4.3.2.1 Principles and methods of site selection for regional soil background pointsa) Site selection for regional soil background points refers to soil sample points that are relatively uncontaminated in or near the survey area, and whose parent material, soil type and farming history are similar to those of the soil in the survey area. b) Background points of the same type of soil are set for several major soil types with strong representativeness and large distribution areas. c) The random site selection method is used, and no less than 3 background points are set for each soil type. 4.3.2.2 Principles and methods for the distribution of farmland soil monitoring points Farmland soil monitoring points refer to soil sampling points where pollutants generated by human activities enter the soil and accumulate to a certain extent, causing or suspected of causing the deterioration of soil environmental quality.
The principle of distribution should be to adhere to the principle of distribution where there is pollution, and to distribute monitoring points in places where pollution is suspected or confirmed. According to technical strength and financial conditions, priority should be given to those places where pollution is serious and affects agricultural production activities. 4.3.2.2.1 The air pollution type soil monitoring points are centered on the air pollution source and adopt the radial distribution method. The distribution density gradually decreases from the center, and the points are evenly distributed within the same density circle. In addition, the monitoring distance and the number of distribution points should be appropriately increased in the downwind direction of the dominant wind of the air pollution source. 4.3.2.2.2 The irrigation water pollution type soil monitoring points are located on both sides of the pollution-receiving irrigation water body, and the strip distribution method is adopted according to the direction of water flow. The distribution density gradually decreases from the pollution-receiving outlet of the irrigation water body, and each irrigation section is relatively evenly distributed.
4.3.2.2.3 Monitoring points for soil contaminated by solid waste piles Surface solid waste piles can be distributed by radial and strip methods in combination with surface runoff and the local perennial dominant wind direction; underground landfill waste piles can be distributed in various forms according to the landfill location. 4.3.2.2.4 Monitoring points for soil contaminated by agricultural solid wastes adopt the uniform distribution method when the application type, application amount, and application time are basically the same. 4.3.2.2.5 Monitoring points for soil contaminated by agricultural chemical substances adopt the uniform distribution method.
4.3.2.2.6 Monitoring points for soil contaminated by comprehensive pollution mainly adopt the radial distribution method, strip distribution method, and uniform distribution method based on the main pollutant emission pathways. 4.4 Sample collection
4.4.1 Sampling preparation
4.4.1.1 Preparation of sampling materials: including sampling tools, equipment, stationery, safety protection supplies, etc. a) Tools: shovel, pickaxe, earth shovel, earth drill, earth knife, wood and bamboo chips, etc. b) Equipment: compass, altimeter, tape measure, ruler, density circle, aluminum basin, sample bag, specimen box, camera, film and other special instruments and chemical reagents.
c) Stationery: sample label, record form, stationery clip, pencil and other small items. d) Safety protection supplies: work clothes, raincoat, non-slip hiking shoes, safety helmet, common medicines, etc. For long-distance and large-scale sampling, vehicles and other transportation tools are still needed.
4.4.1.2 Organizational preparation
Organize a sampling team composed of professionals with certain field investigation experience, familiar with soil sampling technical regulations and responsible work. Before sampling, organize and study the relevant business and technical work plan. 4.4.1.3 Technical preparation
a) Sample point location (or work map) map.
NY/T 395--2000
b) Sample point distribution list, including number, location, soil type, parent material and parent rock, etc. c) Various maps: traffic map, geological map, soil map, large-scale topographic map (with signs of settlements, villages, etc.). d) Sampling record sheet, soil label, etc.
4.4.1.4 Site survey, field location, and determination of sampling plots. a) When the sample points determined on the sample point location map are disturbed by the on-site conditions, appropriate corrections should be made. b) The sampling points should be more than 300m away from railways or main roads. c) Sampling points should not be set near residential buildings, roadsides, ditches, manure piles, waste piles and graves. d) Sampling points should not be set in places with subordinate landscape features such as slopes and depressions. e) Sampling points should be set in plots of about 1-2 hectares with good natural soil conditions, flat ground, and various factors that are relatively stable and representative.
f) After the sampling points are selected, they should be marked and sample point files should be established for long-term monitoring. 4.4.2 Collection stage
4.4.2.1 Soil sampling for soil pollution monitoring, soil pollution accident investigation and legal arbitration of soil pollution disputes is generally carried out in the following three stages.
a) Preliminary sampling: For potentially polluted and contaminated soils, a certain number of samples can be collected for analysis and testing before formal sampling based on background information and on-site investigation results, which are used to preliminarily verify the diffusion mode of pollutants and judge the degree of soil pollution, and provide a basis for selecting the method of site distribution and determining the test items. Preliminary sampling can be carried out simultaneously with the on-site investigation. b) Formal sampling: Before formal sampling, a sampling plan should be formulated. The sampling plan should include the method of site distribution, sample type, number of sample points, sampling tools, quality assurance measures, sample preservation and test items. On-site sampling is carried out according to the sampling plan.
c) Supplementary sampling: After the formal sampling test, if it is found that the sample points do not meet the needs of the investigation, supplementary sampling should be carried out. For example, appropriate points can be added in areas with high pollutant concentrations. 4.4.2.21 The current status of soil environmental quality survey, soil pollution survey of a small area and pollution accident survey of urgent time can adopt a one-time sampling method.
4.4.3 Sample collection
4.4.3.1 Farmland soil surface sample collection
a) The soil profile point shall not be selected in the marginal area where soil types and parent materials are staggered or in the place where the soil profile is damaged. b) The soil surface specification is 1m wide and 1~~2m deep, depending on the soil conditions. The long-cultivated land is sampled to 1m, the newly reclaimed land is sampled to 2m, and the fruit forest land is sampled to 1.5~2m; the saline-alkali land has a high groundwater level, and the sampling is to the groundwater level layer; the mountainous soil layer is thin, and the sampling is to the weathered layer of the parent rock (see Figure 1).
Observation surface
Figure 1 Schematic diagram of soil profile specifications
NY/T 395---2000
c) Use a profile knife to trim the observation surface, and cut off 5cm thick and 10cm wide from top to bottom to form a fresh profile. Accurately divide the soil layers, and collect the soil in the middle layer by layer from bottom to top according to the plum blossom method. Mix the layered soil evenly and take 1kg samples from each layer, bag the layers and record the cards. d) Sampling precautions: When digging the soil profile, the observation side should face the sun, and the topsoil and subsoil should be placed on both sides of the pit. After sampling, backfill according to the original layer. 4.4.3.2 Collection of mixed samples of farmland soil
4.4.3.2.1 Each soil unit consists of at least 3 sampling points, and the sample at each sampling point is a mixed sample of farmland soil. 4.4.3.2.2 Mixed sample collection method
a) Diagonal method: Applicable to farmland soil irrigated with sewage. Draw a diagonal line from the water inlet to the water outlet of the field, divide it into at least five equal parts, and use the equal division points as sampling points. If the soil has great differences, it can be divided into more equal parts, and the number of points is increased. b) Plum blossom method: Applicable to plots with small area, flat terrain, uniform soil material and pollution degree, set about 5 points. c) Chessboard method: Applicable to plots with medium area, flat terrain, and uneven soil, set about 10 points; but for soils polluted by solid waste such as sludge and garbage, the number of points should be more than 20. d) Snake method: Applicable to plots with large area, uneven soil and uneven terrain, set about 15 points, mostly used for agricultural polluted soil.
4.4.4 Sampling depth and sampling volume
For planting general crops, 0-20cm tillage layer soil is collected at each sub-point, and 0-60cm tillage layer soil is collected at each sub-point for planting fruit and forest crops; when understanding the vertical distribution of pollutants in the soil, soil profile samples are collected according to the soil occurrence layer. After mixing at each sub-point, 1kg is taken, and the excess is discarded by quartering.
4.4.5 Sampling time and frequency
4.4.5.1 General soil samples are collected synchronously with crops after harvesting crops. The pollution items that must be tested are collected once a year, and other items are collected once every 3-5 years.
4.4.5.2 When monitoring pollution accidents, sampling should be carried out immediately after receiving the accident report. 4.4.5.3 When monitoring for scientific research, sampling can be carried out at different growth stages or depending on the purpose of the research. 4.4.6 Sampling site records
4.4.6.1 At the same time as sampling, a designated person shall fill in the soil label, sampling record, and sample registration form, and summarize and archive them. See Figure 2 for soil labels; see Table A1 and Table A2 in Appendix A for sampling records and sample registration forms. Soil sample label
Sample number
Sample name
Soil type
Monitoring items
Sampling location
Sampling depth
Sampler
Business code
Sampling time
Figure 2 Soil sample label
4.4.6.2 The filling personnel shall mark the sampling points on the actual field topographic map according to the distance and direction of the obvious ground objects, and unify the numbers with the record cards and labels.
4.4.7 Sampling precautions
4.4.7.1 For samples for heavy metal determination, try to use bamboo shovels or bamboo pieces to directly collect samples, or use iron shovels or soil drills to dig, use bamboo pieces to scrape off the part that contacts the metal sampler, and then use bamboo pieces to collect samples. 4.4.7.2 The collected soil samples are placed in plastic bags and covered with cloth bags. Fill in two copies of the soil label, one in the bag and one tied at the bag mouth. 4.4.7.3 After sampling, each item should be checked on site. If there are missing items, omissions or errors in the sampling record sheet, sample registration sheet, sample bag label, soil sample, sampling point map mark, etc., they should be supplemented and corrected in time before leaving the site. 7
4.5 Sample number
NY/T395--2000
4.5.1 The farmland soil sample number is composed of category code and sequence number. 4.5.1.1 Category code: It is represented by the capital letter of the Chinese pinyin of the environmental element keyword, that is, "T" represents soil. 4.5.1.2 Sequence number: Arabic numerals are used to represent samples collected at different locations. The sample number starts from T001, and one sequence number is a sample at one collection point.
4.5.2 For control points and background samples, add "CK" after the number. 4.5.3 The number of sample registration and sample operation should be consistent with the number of collected samples to prevent confusion. 4.6 Sample transportation
4.6.1 Before shipping, samples must be checked piece by piece with the sample registration form, sample label and sampling record, and then classified and packed. 4.6.2 During transportation, samples must be strictly prevented from loss, confusion or contamination, and special personnel must be assigned to escort them and deliver them to the laboratory on time. The recipient and the sender of the sample both sign the sample registration form, and each party keeps a copy of the sample record for future reference. 4.7 Sample preparation
4.7.1 Sample preparation work site: There should be an air drying room and a sample grinding room. The room should face the sun (strictly prevent direct sunlight from shining on the soil sample), be ventilated, clean, dust-free, and free of volatile chemicals.
4.7.2 Sample preparation tools and containers
4.7.2.1 White sugar porcelain plates and wooden plates are used for drying. 4.7.2.2 Grinding samples: agate grinder, agate mortar, white porcelain mortar, wooden roller, wooden stick, wooden hammer, plexiglass stick, plexiglass plate, hardwood board, colorless polyethylene film, etc.
4.7.2.3 Sieving: nylon sieve, specification is 20~100. 4.7.2.4 Packing: ground-mouth glass bottle with stopper, colorless polyethylene plastic bottle with stopper, colorless polyethylene plastic bag or special kraft paper bag, specification depends on quantity.
4.7.3 Sample preparation procedure
4.7.3.1 Soil sample delivery: The sampling team fills out the sample delivery form in triplicate, submits one copy to the sample management staff, one copy to the processing staff, and the sampling team keeps one copy. After the three parties check and sign, they start grinding the sample. 4.7.3.2 Drying of wet samples: Place the wet samples on a drying tray in the drying room and spread them into a 2cm thick layer. Intermittently crush, stir, and remove impurities such as gravel, sand, and plant residues.
4.7.3.3 Rough grinding of samples: Pour the air-dried samples onto a plexiglass plate in the grinding room, crush them again with a hammer, roller, and rod, remove impurities, and use the quartering method to take the crushed samples, all of which are passed through a 20-mesh nylon sieve. All the sieved samples are placed on a colorless polyethylene film and mixed thoroughly until they are uniform. The coarsely ground samples are divided into two parts using the quartering method, one of which is handed over to the sample warehouse for storage, and the other is used for fine grinding of the samples. The coarsely ground samples can be directly used for soil pH, soil-fill exchange capacity, soil rapid nutrient content, and element availability content analysis. 4.7.3.4 Fine grinding of samples: The samples for fine grinding are divided into two parts by the quartering method for the second time. One part is reserved for use. The other part is ground until all of them pass through a 60-mesh or 100-mesh nylon sieve. The soil sample that passes through a 60-mesh (pore size 0.25mm) sieve is used for analysis of pesticides or soil organic matter, soil total nitrogen, etc.; the soil sample that passes through a 100-mesh (pore size 0.149mm) sieve is used for total analysis of soil elements. 4.7.3.5 Sample packaging: The samples that have been ground and mixed are packaged in sample bags or sample bottles. Fill in two copies of the soil label (the format of the soil label is shown in Figure 2), one copy is placed in the bottle or bag, and one copy is attached to the outside. 4.7.4 Precautions for sample preparation
4.7.4.1 During sample preparation, the soil label and soil sample used for sampling are always placed together, and it is strictly forbidden to mix them up. 4.7.4.2 During the entire process of each sample being air-dried, ground, and packaged and sent to the laboratory, the code of the tools used and the sample container are always consistent.
4.7.4.3 The tools used for sample preparation should be cleaned after each sample is processed to prevent cross contamination. 4.7.4.4 No sample preparation is required for the analysis of volatile and semi-volatile organic pollutants (phenol, cyanide, etc.) or extractable organic matter. Fresh samples should be tested. 4.8 Sample preservation
4.8.1 Air-dried soil samples should be classified and stored in the sample library according to different numbers and particle sizes and stored for half a year to one year. Or after all analysis tasks are completed and the inspection is correct, if there is no need to keep them, they can be discarded. NY/T 395-2000
4.8.2 Fresh soil samples are used for the analysis of volatile and semi-volatile organic pollutants (phenol, cyanide, etc.) or extractable organic matter. Fresh soil samples should be placed in glass bottles in the refrigerator at less than 4°C for half a month. 4.8.3 The soil sample library should always be kept dry, ventilated, without direct sunlight and pollution; samples should be checked regularly to prevent mildew, rodent damage and soil label shedding.
5 Monitoring items and analysis methods for farmland soil environmental quality 5.1 Principles for determining monitoring items
5.1.1 Required items: Pollutants required to be controlled in GB15618. 5.1.2 Selection of required items: Pollutants that are not required to be controlled in GB15618, but are confirmed to have accumulated more in the soil according to local environmental pollution conditions (such as agricultural air, agricultural irrigation water, etc.), have a greater impact on agricultural production, have a wide range of impact, and are highly toxic. These items are also required items. Specific items are determined by local areas.
5.1.3 Selection items: Local areas select and measure them. The selected items generally include the following categories: a) New pollutants that accumulate less in the soil; b) Soil property indicators that have changed due to environmental pollution; c) Agricultural ecological environment indicators.
5.2 Principles for selecting analytical methods
5.2.1 Method: Standard method (i.e. arbitration method), which is the analytical method selected in the soil environmental quality standard. 5.2.2 Second method: the method prescribed or recommended by the authority. 5.2.3 Third method: according to the actual situation of each station, select the equivalent method. However, a comparative experiment should be conducted, and its detection limit, accuracy and precision should not be lower than the requirements of the corresponding general method or the requirements for accurate quantification of the analyte. 5.3 Monitoring items and analysis methods
The monitoring items and analysis methods of farmland soil are shown in Table 1. Table 1 List of monitoring items and analysis methods for farmland soil Monitoring items
BHC
Monitoring instruments
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic fluorescence photometer
Mercury meter
Spectrophotometer
Spectrophotometer
Atomic fluorescence photometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Spectrophotometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Gas chromatograph
Monitoring methods
Graphite furnace atomic absorption Absorption spectrophotometry
KI-MIBK extraction atomic absorption spectrophotometry Cold atomic fluorescence spectrometry
Ring source absorption method
Ethyl dithiocarbamate silver spectrophotometry Potassium borohydride Silver nitrate spectrophotometry
Hydride-nondispersive atomic fluorescence spectrometry
Flame atomic absorption spectrophotometry
Graphite furnace atomic absorption spectrophotometry
KI-MIBK extraction atomic absorption spectrophotometry Flame atomic absorption spectrophotometry
Diphenylcarbazide spectrophotometry
Flame atomic absorption spectrophotometry
Flame atomic absorption spectrophotometry
Gas chromatography
Method source
GB/T 17141
GB/T17140
&Modern analysis method of soil elements》
GB/T17136
GB/T17134
GB/T17135
《Modern analysis method of soil fill elements》
GB/T 17138
GB/T17141
GB/T 17140
GB/T 17137
《Modern analysis method of soil elements》
GB/T17138
GB/T 17139
GB/T14550
Monitoring Items
DDT
Organic Matter
Available Phosphorus
Available Boron
Chloride
Mineral Oil
Benzo(a)pyrene
Total Salt Content
Monitoring Instruments
Gas Chromatograph
Ion Meter
Atomic Absorption Spectrometer
Atomic Absorption Spectrometer|| tt||Atomic absorption spectrometer
Micro burette
Semi-micro nitrogen analyzer
Spectrophotometer
Spectrophotometer
Analytical balance
Atomic fluorescence photometer
Spectrophotometer
Spectrophotometer
Spectrophotometer
Spectrophotometer
Ion meter
Oil concentration analyzer
Spectrophotometer
Analytical balance
NY/ T395—2000
Table 1 (end)
Monitoring methods
Gas chromatography
Glass electrode method
Flame atomic absorption spectrophotometry
Flame atomic absorption spectrophotometry
Flame atomic absorption spectrophotometry
Potassium dichromate volumetric method
Semi-micro method
Molybdenum antimony photometric method
Molybdenum antimony photometric method
Gravimetric method||tt ||Atomic fluorescence method
Curcumin photometry
Methylene blue photometry
Potassium thiocyanate photometry
Ion selective electrode method
Silver nitrate titration
5A molecular sieve adsorption method
Extraction chromatography
Gravimetric method
6 Laboratory analysis quality control and quality assurance for farmland soil environmental quality monitoring 6.1 Laboratory routine analysis quality control procedures Method source
GB/T 14550
"Modern Analysis Methods for Soil Elements"
"Modern Analysis Methods for Soil Elements"
"Modern Analysis Methods for Soil Elements"
"Modern Analysis Methods for Soil Elements"
NY/T 85
NY/T 53
NY/T 149
NY/T 88
NY/T 52
"Modern Analysis Methods for Soil Elements"
NY/T148
"Modern Analysis Methods for Soil Elements"
Selected by Agricultural Departments
"Modern Analysis Methods for Soil Elements"
"Soil Physical and Chemical Analysis"
Selected by Agricultural Departments
Selected by Agricultural Departments
"Soil Physical and Chemical Analysis"
The implementation of quality control in the laboratory should be carried out under the guidance of quality control personnel and technical leaders. After determining the monitoring items, appropriate methods should be selected and basic training should be carried out on the methods. At the same time, corresponding quality control techniques should be implemented. The routine quality control procedures are shown in Figure 3.
Blank value determination
Determination items
Determination methods
Basic experiments
NY/T 395—2000
Internal review
Review by quality controller
Calibration curve verification
Detection limit estimation
Calibration curve drawing
Certificate of conformity
Actual sample measurement
Quality control sample measurement
Sample analysis and
Application of quality control technology
Measurement results
Review by technical director of laboratory
Original records
Monitoring report Level 3 review
Figure 3 Routine analytical quality control procedures
6.2 Laboratory basics
6.2.1 Analytical balance and code
6.2.1.1 The graduation value of the analytical balance used for precise weighing should be one ten-thousandth of a gram or one hundred-thousandth of a gram, and its accuracy should not be lower than that of the third-level balance and the third-level magnetic code.
6.2.1.2 During the use of the balance, the unequal arm (single-arm balance does not have this problem), the variability of the indication, the sensitivity and its change with load should be checked regularly.
6.2.1.3 The balance and scale should be sent to the metrology department for verification once a year, and those that pass the verification can be used. 6.2.2 Glass measuring instruments
The accuracy of the glass measuring instruments used is divided into A and B. grades. The burettes, pipettes and volumetric flasks used to prepare the original solution or calibration solution must be sent to the metrology department for verification before use. During use, according to the relevant national metrology verification cycle regulations, regular inspections or self-inspections should be carried out. 6.2.3 Testing instruments and equipment
Precision and large instruments and equipment are kept and used by designated personnel. Before use, the status of the instruments and equipment must be checked and verified by the metrology department regularly. Those that fail the verification or exceed the verification period shall not be used for testing. 6.2.4 Reagents for experiments
According to the requirements of the experimental method, select and prepare reagents of appropriate levels. If the reagent level does not meet the requirements, it should be purified or refined. 6.2.5 Pure water for experiments
6.2.5.1 According to the requirements of the experimental method, prepare the experimental water by distillation, ion exchange, quartz distillation and other methods separately or in combination. 6.2.5.2 The resistance of the water used for preparing laboratory reference solution, standard solution, diluted standard working solution and microgram/liter analysis should not be less than 3 MQ/cm (25C).
6.2.5.3 The resistivity of the water used for preparing reagents for general analysis items, including the final washing water of the container, should be greater than 0.5MQ/cm (25℃). 6.2.5.4 Special requirements for analytical water, except for its resistivity greater than 0.5MQ/cm (25℃), shall be prepared according to the method specified in the analytical method and can be used only after passing the inspection.
6.2.6 Standard substances and standard solutions
6.2.6.1 The standard substances required for testing must be selected from the first-level and second-level standard substances published by the country or department that are similar to the test matrix, and used for calibration of analytical instruments, inspection of analytical methods, preparation of standard solutions and homemade quality control samples. 11
NY/T 395-2000
6.2.6.2 The quality control samples developed by each station should be compared with national standard samples to ensure reliable data and stable performance. 6.2.6.3 Reference reagents, reference substances and standard substances must be used to prepare standard solutions. The concentration, stability, storage method and validity period of standard stock solutions should strictly follow the provisions of the analytical method. 6.2.6.4 For monitoring items that have standard samples, the value is tracked once a year, and it is strictly forbidden to provide and use standard substances that have exceeded the shelf life.
6.2.6.5 Prepare standard solution by precise weighing method, weigh at least 2 standard solutions independently, and the relative error of the measured signal value should be less than 2%: the standard solution prepared by reference solution calibration method should be calibrated in parallel for at least 3 times, and the average value should be taken. 6.2.7 Laboratory environment
6.2.7.1 The laboratory layout is reasonable, and the instruments and equipment are placed appropriately for easy operation, and the test items do not interfere with each other. 6.2.7.2 The laboratory is clean and tidy, and its temperature, humidity, dust prevention, noise, and anti-interference can meet the requirements of monitoring work. 6.2.7.3 There should be safety management measures for water, electricity, and gas in the laboratory, and there should be treatment measures for harmful substances such as wastewater, waste gas, and waste residue produced. 6.2.8 Basic qualities of laboratory monitoring personnel
Monitoring personnel should be familiar with relevant environmental protection laws and regulations, monitoring specifications, standards and monitoring methods, master the theories and operational skills related to monitoring, and hold a certificate after business assessment.
6.3 Laboratory Internal Quality Control
6.3.1 Basic Experiments for Analytical Quality Control
6.3.1.1 Determination of Blank Value of the Whole Procedure
The blank value of the whole procedure refers to the measurement signal value or corresponding concentration value caused by all factors in the entire analytical process when a certain method is used to measure a certain substance, except that the sample does not contain the measured substance. Two parallel samples are measured each time, and the measurement is carried out for 5 consecutive days. The standard deviation Swb of the results of 10 measurements is calculated according to formula (1):
[2(X: +x)
m(n - 1)
Where: n——number of parallel samples measured per day; m——number of measurement days.
6.3.1.2 Detection Limit
The detection limit refers to the minimum concentration or minimum amount of the substance to be measured that can be detected from the sample within a given confidence level for a specific analytical method. The detection limit (95% confidence level) is calculated according to the following formula based on the intra-batch standard deviation (Swb) of the blank determination. 6.3.1.2.1 If there is a significant difference between the value of the sample once determined and the value of the zero-concentration sample once determined, the detection limit is calculated according to formula (2): L2V2tySwb
wherein: L-method detection limit;
tr(0.05) is the critical value of t distribution when the one-sided significance level is 5% and the intra-batch freedom degree is f=m (n-1); Swb is the intra-batch standard deviation of the blank value when the number of determinations is n; f is the intra-batch freedom degree, f=m(n-1); m is the number of repeated determinations, n is the number of parallel determinations; t is the t value when the significance level is 0.05 (one-sided) and the freedom degree is f. 6.3.1.2.2 In the atomic absorption analysis method, the detection limit is calculated using formula (3): L = 3Swb
Where: Swb blank value batch standard deviation. ........( 2 )
·(3)
The L value calculated from the measured blank value should not be greater than the detection limit specified in the analysis method. If it is greater than the value specified in the method, the reason must be found to reduce the blank value and re-measure and calculate until it is qualified. 6.3.1.2.3 The value of the detection limit in the work
Spectrophotometry (including atomic absorption spectrophotometry) uses the concentration value corresponding to the absorbance value of 0.010 after deducting the blank value as the detection limit.
NY/T 395--2000
Gas chromatography is expressed as the minimum detection amount or minimum detection concentration. The minimum detection amount refers to the minimum amount of material that needs to enter the chromatographic column when the detector can just produce a response signal twice the noise; the minimum detection concentration refers to the ratio of the minimum detection amount to the injection amount (volume). The ion-selective electrode method uses the concentration value corresponding to the intersection point when the extension line of the straight part of the calibration curve intersects with the straight line passing through the blank potential and parallel to the concentration axis.
6.3.2 Drawing, inspection and use of calibration curve 6.3.2.1 Drawing of calibration curve
According to the steps of the analytical method, set more than 6 standard series concentration points, subtract the measured signal value of the zero concentration point from the measured signal value of each concentration point, and draw the correction curve after calculating the linear regression equation. When the sample pretreatment is complicated and the contamination and loss cannot be ignored, it should be treated in the same way as the sample before measuring and drawing the calibration curve. After the calibration curve regression calculation, its intercept should be controlled within ±0.005 unless otherwise specified. If the intercept is too large, an intercept test must be carried out and it can only be used after passing the test. The correlation coefficient of the calibration curve should be greater than 0.99 (determined according to the concentration of the measured component, the method used, etc.). When the analytical conditions and methods themselves are relatively stable, the calibration curve can be used continuously. At this time, the blank and two concentration points on the calibration curve should be measured with the sample, and the concentration points corresponding to the original calibration curve should be compared. The relative deviation should not exceed 5%~10%, otherwise it should be redrawn.
6.3.2.2 Check of the calibration curve
6.3.2.2.1 Linearity test: that is, the precision test of the calibration curve. When the correlation coefficient of the calibration curve is less than 0.99, the outliers of the measured values at each point of the calibration curve should be checked, and the tolerance value should be calculated according to formula (4), formula (5), and formula (6): d,
Tolerance value=
d, = yi (a +br,)
where ·d.-
Residual;
Signal value;
α—intercept;
b——slope;
α;—concentration value;
Sy—--Residual standard deviation;
--Number of concentration points excluding zero concentration.
·(5)
The tolerance value is usually 1.5; if it is greater than 1.5, the measured value of the concentration point is an outlier, and the concentration point should be re-measured until it is satisfactory. When r>0.999, outliers usually do not appear, so there is no need to check. 6.3.2.2.2 Test of intercept α: that is, test of accuracy of calibration curve. When a<0.005, no test is necessary. When the confidence level is 95%, the intercept a is tested against 0. When there is no significant difference, a=0, and the concentration can be calculated by regression equation. When the intercept α is significantly different from 0, the cause should be found and corrected, and then the curve should be redrawn and tested before use. 6.3.2.2.3 General comment: When all or two of the calibration points (including blank) do not fall into the confidence interval, the standard series must be remeasured and a new curve drawn. When two or three points all fall into the confidence interval, the original calibration curve can be used. 6.3.2.3 Use of calibration curve: If the calibration curve is unqualified, it cannot be used. When used, it must not exceed the concentration range of the standard series at will, it must not be used for a long time, and it must not be borrowed from each other.
6.3.3 Precision Control
6.3.3.1 Determination Rate: For all items that can be analyzed in parallel, 10% to 15% of the samples should be analyzed in parallel for each item in each batch of samples. If there are less than 5 samples, the rate should be increased to more than 50%. 6.3.3.2 Determination Method: Clear code parallel samples programmed by the analyst; or coded parallel samples programmed by the quality control personnel at the sampling site or laboratory.The detection limit is calculated according to formula (2): L2V2tySwb
Wherein: L-method detection limit;
tr(0.05) unilateral significance level is 5%, and the intra-batch freedom degree f=m(n-1), the critical value of t distribution; Swb——intra-batch standard deviation of blank value with n measurements; f---intra-batch freedom, f=m(n-1); m is the number of repeated measurements, n is the number of parallel measurements; t--significance level is 0.05 unilateral), and the freedom degree is f. 6.3.1.2.2 In the atomic absorption analysis method, the detection limit is calculated according to formula (3): L=3Swb
Wherein: Swb is the intra-batch standard deviation of blank value. ........( 2 )
·（3）bZxz.net
The L value calculated from the measured blank value should not be greater than the detection limit specified in the analytical method. If it is greater than the value specified in the method, the reason must be found to reduce the blank value and re-measure and calculate until it is qualified. 6.3.1.2.3 Value of detection limit in work
Spectrophotometry (including atomic absorption spectrophotometry) uses the concentration value corresponding to the absorbance value of 0.010 after deducting the blank value as the detection limit.
NY/T 395--2000
Gas chromatography is expressed in terms of minimum detection amount or minimum detection concentration. Minimum detection amount refers to the minimum amount of substance required to enter the chromatographic column when the detector can just produce a response signal of twice the noise; minimum detection concentration refers to the ratio of the minimum detection amount to the injection amount (volume). The concentration value corresponding to the intersection of the extended line of the straight part of the calibration curve and the straight line through the blank potential and parallel to the concentration axis in the ion selective electrode method.
6.3.2 Drawing, inspection and use of calibration curve 6.3.2.1 Drawing of calibration curve
According to the steps of the analytical method, set more than 6 standard series concentration points, subtract the measured signal value of the zero concentration point from the measured signal value of each concentration point, and draw the calibration curve after calculating the linear regression equation. When the sample pretreatment is complicated and the contamination and loss cannot be ignored, it should be treated in the same way as the sample before measuring and drawing the calibration curve. After the calibration curve regression calculation, its intercept should be controlled within ±0.005 unless otherwise specified. If the intercept is too large, an intercept test must be carried out and it can only be used after passing the test. The correlation coefficient of the calibration curve should be greater than 0.99 (determined according to the concentration of the measured component, the method used, etc.). When the analytical conditions and methods are relatively stable, the calibration curve can be used continuously. At this time, the blank and two concentration points on the calibration curve should be measured with the sample, and the concentration points corresponding to the original calibration curve should be compared. The relative deviation should not exceed 5%~10%, otherwise it should be redrawn.
6.3.2.2 Check of calibration curve
6.3.2.2.1 Linearity test: that is, the precision test of the calibration curve. When the correlation coefficient of the calibration curve is less than 0.99, the outliers of the measured values at each point of the calibration curve should be checked, and the tolerance value should be calculated according to formula (4), formula (5), and formula (6): d,
Tolerance value=
d, = yi (a +br,)
where ·d.-
Residual;
Signal value;
α—intercept;
b——slope;
α;—concentration value;
Sy—--Residual standard deviation;
--Number of concentration points excluding zero concentration.
·(5)
The tolerance value is usually 1.5; if it is greater than 1.5, the measured value of the concentration point is an outlier, and the concentration point should be re-measured until it is satisfactory. When r>0.999, outliers usually do not appear, so there is no need to check. 6.3.2.2.2 Test of intercept α: that is, test of accuracy of calibration curve. When a<0.005, no test is necessary. When the confidence level is 95%, the intercept a is tested against 0. When there is no significant difference, a=0, and the concentration can be calculated by regression equation. When the intercept α is significantly different from 0, the cause should be found and corrected, and then the curve should be redrawn and tested before use. 6.3.2.2.3 General comment: When all or two of the calibration points (including blank) do not fall into the confidence interval, the standard series must be remeasured and a new curve drawn. When two or three points all fall into the confidence interval, the original calibration curve can be used. 6.3.2.3 Use of calibration curve: If the calibration curve is unqualified, it cannot be used. When used, it must not exceed the concentration range of the standard series at will, it must not be used for a long time, and it must not be borrowed from each other.
6.3.3 Precision Control
6.3.3.1 Determination Rate: For all items that can be analyzed in parallel, 10% to 15% of the samples should be analyzed in parallel for each item in each batch of samples. If there are less than 5 samples, the rate should be increased to more than 50%. 6.3.3.2 Determination Method: Clear code parallel samples programmed by the analyst; or coded parallel samples programmed by the quality control personnel at the sampling site or laboratory.The detection limit is calculated according to formula (2): L2V2tySwb
Wherein: L-method detection limit;
tr(0.05) unilateral significance level is 5%, and the intra-batch freedom degree f=m(n-1), the critical value of t distribution; Swb——intra-batch standard deviation of blank value with n measurements; f---intra-batch freedom, f=m(n-1); m is the number of repeated measurements, n is the number of parallel measurements; t--significance level is 0.05 unilateral), and the freedom degree is f. 6.3.1.2.2 In the atomic absorption analysis method, the detection limit is calculated according to formula (3): L=3Swb
Wherein: Swb is the intra-batch standard deviation of blank value. ........( 2 )
·（3）
The L value calculated from the measured blank value should not be greater than the detection limit specified in the analytical method. If it is greater than the value specified in the method, the reason must be found to reduce the blank value and re-measure and calculate until it is qualified. 6.3.1.2.3 Value of detection limit in work
Spectrophotometry (including atomic absorption spectrophotometry) uses the concentration value corresponding to the absorbance value of 0.010 after deducting the blank value as the detection limit.
NY/T 395--2000
Gas chromatography is expressed in terms of minimum detection amount or minimum detection concentration. Minimum detection amount refers to the minimum amount of substance required to enter the chromatographic column when the detector can just produce a response signal of twice the noise; minimum detection concentration refers to the ratio of the minimum detection amount to the injection amount (volume). The concentration value corresponding to the intersection of the extended line of the straight part of the calibration curve and the straight line through the blank potential and parallel to the concentration axis in the ion selective electrode method.
6.3.2 Drawing, inspection and use of calibration curve 6.3.2.1 Drawing of calibration curve
According to the steps of the analytical method, set more than 6 standard series concentration points, subtract the measured signal value of the zero concentration point from the measured signal value of each concentration point, and draw the calibration curve after calculating the linear regression equation. When the sample pretreatment is complicated and the contamination and loss cannot be ignored, it should be treated in the same way as the sample before measuring and drawing the calibration curve. After the calibration curve regression calculation, its intercept should be controlled within ±0.005 unless otherwise specified. If the intercept is too large, an intercept test must be carried out and it can only be used after passing the test. The correlation coefficient of the calibration curve should be greater than 0.99 (determined according to the concentration of the measured component, the method used, etc.). When the analytical conditions and methods are relatively stable, the calibration curve can be used continuously. At this time, the blank and two concentration points on the calibration curve should be measured with the sample, and the concentration points corresponding to the original calibration curve should be compared. The relative deviation should not exceed 5%~10%, otherwise it should be redrawn.
6.3.2.2 Check of calibration curve
6.3.2.2.1 Linearity test: that is, the precision test of the calibration curve. When the correlation coefficient of the calibration curve is less than 0.99, the outliers of the measured values at each point of the calibration curve should be checked, and the tolerance value should be calculated according to formula (4), formula (5), and formula (6): d,
Tolerance value=
d, = yi (a +br,)
where ·d.-
Residual;
Signal value;
α—intercept;
b——slope;
α;—concentration value;
Sy—--Residual standard deviation;
--Number of concentration points excluding zero concentration.
·(5)
The tolerance value is usually 1.5; if it is greater than 1.5, the measured value of the concentration point is an outlier, and the concentration point should be re-measured until it is satisfactory. When r>0.999, outliers usually do not appear, so there is no need to check. 6.3.2.2.2 Test of intercept α: that is, test of accuracy of calibration curve. When a<0.005, no test is necessary. When the confidence level is 95%, the intercept a is tested against 0. When there is no significant difference, a=0, and the concentration can be calculated by regression equation. When the intercept α is significantly different from 0, the cause should be found and corrected, and then the curve should be redrawn and tested before use. 6.3.2.2.3 General comment: When all or two of the calibration points (including blank) do not fall into the confidence interval, the standard series must be remeasured and a new curve drawn. When two or three points all fall into the confidence interval, the original calibration curve can be used. 6.3.2.3 Use of calibration curve: If the calibration curve is unqualified, it cannot be used. When used, it must not exceed the concentration range of the standard series at will, it must not be used for a long time, and it must not be borrowed from each other.
6.3.3 Precision Control
6.3.3.1 Determination Rate: For all items that can be analyzed in parallel, 10% to 15% of the samples should be analyzed in parallel for each item in each batch of samples. If there are less than 5 samples, the rate should be increased to more than 50%. 6.3.3.2 Determination Method: Clear code parallel samples programmed by the analyst; or coded parallel samples programmed by the quality control personnel at the sampling site or laboratory.3 General comments: When all or two of the calibration points (including blank) added do not fall within the confidence interval, the standard series must be re-measured and a new curve must be drawn. When two or three points all fall within the confidence interval, the original calibration curve can be used. 6.3.2.3 Use of calibration curve: The calibration curve cannot be used if it is unqualified. When used, it must not exceed the concentration range of the standard series at will, it must not be used for a long time, and it must not be borrowed from each other.
6.3.3 Precision control
6.3.3.1 Determination rate: For all items that can be analyzed in parallel, 10% to 15% parallel samples must be made for each item in each batch of samples. If there are less than 5 samples, the rate should be increased to more than 50%. 6.3.3.2 Determination method: Clearly coded parallel samples compiled by the analyst; or coded parallel samples compiled by the quality control personnel at the sampling site or laboratory.3 General comments: When all or two of the calibration points (including blank) added do not fall within the confidence interval, the standard series must be re-measured and a new curve must be drawn. When two or three points all fall within the confidence interval, the original calibration curve can be used. 6.3.2.3 Use of calibration curve: The calibration curve cannot be used if it is unqualified. When used, it must not exceed the concentration range of the standard series at will, it must not be used for a long time, and it must not be borrowed from each other.
6.3.3 Precision control
6.3.3.1 Determination rate: For all items that can be analyzed in parallel, 10% to 15% parallel samples must be made for each item in each batch of samples. If there are less than 5 samples, the rate should be increased to more than 50%. 6.3.3.2 Determination method: Clearly coded parallel samples compiled by the analyst; or coded parallel samples compiled by the quality control personnel at the sampling site or laboratory.
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