Procedural regulations regarding monitoring of pollutants in the produces of agriculture,animal husbandry and fishery
Some standard content:
NY/T398-2000
According to the relevant provisions of the National Environmental Monitoring Management Regulations and the Agricultural Environmental Monitoring 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 is specially formulated. Appendix A of this standard is the appendix of the standard. This standard is proposed by the Science and Technology Education Department of the Ministry of Agriculture. The drafting units of this standard are: the Ministry of Agriculture Environmental Monitoring Center and the Heilongjiang Provincial Agricultural Environmental Protection Station. The main drafters of this standard are: Liu Suyun, Xu Zhiqiang, Zhan Xinhua, Liu Fengzhi, Tao Zhan. 68
1 Scope
Agricultural Industry Standard of the People's Republic of China
Procedural regulations regardingmonitoring of pollutants in the produces ofagriculture,animal husbandry and fisheryNY/T 398—2000
This standard specifies the basic requirements for sampling, analysis methods, quality control, data processing and expression of results in monitoring of pollution in agricultural, animal husbandry and fishery.
This standard is applicable to monitoring of pollution in agricultural, animal husbandry and fishery. 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 versions of the following standards. GB/T 5009.11—1996
GB/T 5009. 12-1996
GB/T 5009.13—1996
GB/T 5009. 14---1996
GB/T 5009.15—1996
GB/T .17--1996
GB/T 5009.18—1996
GB/T 5009. 19--1996
GB/T5009.20—1996
GB/T 5009.27—1996
GB/T 5009.33--1996
GB/T 5009.36—1996
GB 12399. 20--1990
Method for determination of total arsenic in foods
Method for determination of lead in foods
Method for determination of copper in foods
Method for determination of zinc in foods
Method for determination of cadmium in foods
Method for determination of total mercury in foods
Method for determination of fluorine in foods
Method for determination of 666 and DDT residues in foodsMethod for determination of organophosphorus pesticide residues in foodsMethod for determination of benzo(a)pyrene in foods
Method for determination of nitrite and nitrate in foodsMethod for determination of heptachlor, aldrin and dieldrin residues in foodsMethod for determination of selenium in foods
GB/T 14929. 4—1994
GB/T 14962--1994
GB/T 16343--1996
Method for determination of cypermethrin, cypermethrin and deltamethrin residues in foodsMethod for determination of chromium in foods
Determination of nickel in foods
NY/T395—2000 Technical specification for monitoring environmental quality of farmland soil 3 Definitions
This standard adopts the following definitions.
Agricultural, livestock and aquatic products
Common agricultural products in my country (cereals, oilseeds, fruits, vegetables, economic specialties, aquatic plants, etc.), livestock and poultry products (meat, eggs, dairy products) and aquatic products (fish, shellfish, shellfish, etc.) original products and primary processed products. 4 Sampling techniques for monitoring pollution in agricultural, livestock and aquatic products 4.1 Sampling techniques for crop samples
4.1.1 When crop monitoring and farmland soil monitoring are carried out simultaneously, crop samples should be collected simultaneously with farmland soil samples, and the crop sampling point is the farmland soil sampling point. 4.1.2 When monitoring crops, the on-site investigation and data collection before sampling, the division of monitoring units, the layout of sampling points, and the sampling methods are similar to those of farmland soil. The specific steps and methods are as follows. 4.1.2.1 On-site investigation and data collection before sampling a) Regional natural environment characteristics: water, meteorology, topography, vegetation, natural disasters, etc. b) Agricultural production land use status: crop types, layout, area, yield, crop growth, farming system, etc. c) Soil environmental pollution status: types and distribution of industrial pollution sources, types and emission pathways of pollutants and annual emissions, agricultural irrigation water pollution status, air pollution status, agricultural solid waste input, agricultural chemical input, natural pollution source status, etc. d) Crop pollution monitoring data: background value of crop pollution elements, current status of crop pollution. e) Other relevant data and maps: overall planning of land use, agricultural resource survey planning, administrative division map, crop planting distribution map, soil type map, etc.
4.1.2.2 Division of monitoring units
Crop monitoring units should be divided into basic units based on the way crops in the monitoring area are polluted, and the local agricultural environment monitoring department should delineate them according to the actual situation, combined with reference to soil pollution types, crop types, commercial grain production bases, protected area categories, administrative divisions and other factors. The differences between the same units should be minimized as much as possible. 4.1.2.2.1 Air pollution type crop monitoring unit The pollution in the monitoring area mainly comes from air pollutants, causing crops to be polluted. 4.1.2.2.2 Irrigation water pollution type crop monitoring unit The pollution in the monitoring area mainly comes from polluted agricultural irrigation water, causing crops to be polluted. 4.1.2.2.3 Agricultural pollution type crop monitoring unit The pollution in the monitoring area mainly comes from garbage, sludge, pesticides, fertilizers, growth hormones and other agricultural substances, causing crops to be polluted. 4.1.2.2.4 Waste pile pollution type crop monitoring unit The pollution in the monitoring area mainly comes from concentrated solid waste, causing crops to be polluted. 4.1.2.2.5 Comprehensive pollution-type crop monitoring unit The pollution in the monitoring area mainly comes from the above two or more ways, causing the crops to be polluted. 4.1.2.3 Layout of monitoring points
4.1.2.3.1 Number of points
When crop monitoring and soil monitoring are carried out at the same time, the number of crop sample points and sampling points should be kept consistent with the number of soil sample points and sampling points as much as possible, and the number of monitoring sample points can be reduced as appropriate. When only crop monitoring is carried out, the number of points for crop monitoring should be determined based on factors such as the purpose of the survey, the accuracy of the survey, and the environmental conditions of the survey area. "--Generally, each monitoring unit should have at least 3 points. 4.1.2.3.2 Point distribution method
4.1.2.3.2.1 Regional crop background point (control point) distribution principle and method Regional crop background point distribution refers to the crop sample points collected on the plots in or near the survey area that are relatively unpolluted and have similar farming systems and farming histories to the survey area. Point distribution requirements: Several major crop pollution types with strong representativeness and large distribution areas are respectively distributed with similar crop background points; using the random distribution method, each crop pollution type shall not be less than 3 background points. 4.1.2.3.2.2 Principles and methods of crop monitoring point layout The layout of crop monitoring points should adhere to the principle of where there is pollution. The monitoring points should be laid out in suspected or confirmed pollution areas. According to economic and technical conditions, the layout should give priority to major grain production areas and commodity production bases with serious crop pollution and great impact. The focus of monitoring point layout should be: plots irrigated with sewage or polluted water; plots around factories, mines, enterprises and towns; plots around places where industrial waste residues and urban garbage are piled up in large quantities; plots affected by industrial waste gas and dust for a long time; plots where a large amount of agricultural chemicals are used; plots where sludge, urban garbage, solid waste and fertilizers made from waste are used for a long time. The layout of crop monitoring points should be determined according to the type of pollution in the monitoring area. The specific requirements are as follows: a) Crop monitoring points in air pollution monitoring areas: With air pollution sources as the center, the radial layout method is adopted. The density of points gradually decreases from the center, and points are evenly distributed within the same density circle. In addition, the monitoring distance and the number of points should be appropriately increased in the downwind direction of the dominant wind of the atmospheric pollution source.
b) Crop monitoring points in the irrigation water pollution monitoring area: on both sides of the polluted irrigation water body, the strip distribution method is adopted according to the water flow direction. The density of points gradually decreases from the pollution inlet of the irrigation water body, and each irrigation section is relatively uniform. c) Crop monitoring points in the solid waste dump pollution monitoring area: combined with surface runoff and the local perennial dominant wind direction, the radial distribution method and the strip distribution method are adopted.
d) Crop monitoring points in the agricultural pollution monitoring area: the uniform distribution method is adopted when the application type, application amount, application time, etc. are basically the same.
c) Comprehensive pollution crop monitoring points: mainly based on the main pollutant emission pathways, the radial distribution method, the strip distribution method and the uniform distribution method are adopted.
4.1.3 Sample collection
4.1.3.1 Sampling preparation
4.1.3.1.1 Sampling material preparation
a) Tools: stainless steel scissors, stainless steel cutters, sickles, shovels, bamboo poles, wooden ladders, etc. b) Equipment: compass, altimeter, tape measure, ruler, sample bag, camera, film and other special instruments and chemical reagents. c) Stationery: small items such as sample labels, record forms, stationery clips, pencils, etc. d) Safety protection supplies: work clothes, raincoats, non-slip hiking shoes, safety helmets, common medicines, etc. For long-distance and large-scale sampling, vehicles and other means of transportation are still needed.
4.1.3.1.2 Organizational preparation
Organize a sampling team composed of professionals with certain field investigation experience, familiar with the technical procedures for crop sampling, and responsible for their work. Before sampling, organize learning of relevant business and technical work plans. 4.1.3.1.3 Technical preparation
a) Sample point location (or working map) map.
b) Sample point distribution list, including number, location, crop type, representative area, etc. c) Various maps: traffic map, crop planting map, soil pollution status map, large-scale administrative district map (with residential areas, villages, etc.), etc.
d) Sampling record sheet, crop sample label, etc. 4.1.3.1.4 Site survey, field point determination, and determination of sampling plots a) When the sample points determined on the sample point location map are disturbed by the on-site situation, appropriate corrections should be made. b) The sampling point should be more than 300m away from the railway or main highway. c) Sampling points should not be set near residential houses, roadsides, ditches, manure piles, waste piles and graves. d) Sampling points should be set in plots of about 1 to 2 hm with good natural soil conditions, flat ground, and relatively stable and representative factors.
e) Once the sampling points are selected, they should be marked and a sample point file should be established for long-term monitoring. 4.1.3.2 Sampling methods
Collection of crop samples: mixed samples should be collected. Except for special research projects, single plants cannot be used as monitoring samples. Mixed samples of crops refer to multi-point sampling in the plots of the designated sampling points according to different situations using the diagonal method, plum blossom method, chessboard method, snake method, etc., and then mixed in equal amounts to form a mixed sample. Each mixed sample consists of more than 5 to 10 plants for large fruits (i.e., point sampling); small fruits consist of more than 10 to 20 plants. a) Collection of crop samples: 0.1 to 0.2 hm2 is used as the sampling unit, and 5 to 20 plants are selected in the sampling unit. For rice and wheat, rice ears and wheat ears are collected; for corn, the first ear, that is, the ear close to the ground surface, is collected and mixed into samples. b) Collection of fruit tree samples: 0.10.2hm2 is used as a sampling unit, 5~10 fruit trees are selected in the sampling unit, each fruit tree is divided into four parts longitudinally, and the upper, lower, middle, inner and outer sides of one part are evenly picked and mixed into samples. c) Collection of vegetable samples: 0.1~0.3hm2 is used as a sampling unit, and 5~20 plants are selected in the sampling unit. Small-sized leafy vegetables (cabbage, leek, etc.) are collected from the whole plant after removing the roots; large-sized leafy vegetables can be sampled by radial cutting method, that is, each plant is cut into eight small petals from the surface leaves to the heart leaves, and two petals are randomly selected for the plant; roots and stems are collected, and large roots and stems can be sampled by radial cutting method; fruits are evenly picked from the upper, middle and lower sides of the plant and mixed into samples. d) Collection of tobacco and tea samples: 0.1-0.2hm2 is used as the sampling unit, and 15-20 plants are randomly selected in the sampling unit. Leaves from multiple parts of each plant, such as the upper, middle and lower parts, are collected and mixed into samples. Do not take old leaves or new leaves alone as representative samples. e) For aquatic plants (such as duckweed, kelp, algae, etc.), the whole plant is collected evenly from the water body. If the samples are collected from seriously polluted water bodies, the samples must be washed and the water plants, small snails and other debris must be removed. 4.2 Sampling of livestock and aquatic products
4.2.1 On-site investigation and data collection before sampling4.2.1.1 Current status of livestock and poultry and aquatic product production: production scale, variety, quantity, commodity rate, etc. 4.2.1.2 Investigation and collection of current status of environmental pollution in production bases: pollution of water bodies, soil, crops and feed used for livestock and poultry and aquaculture, etc.
4.2.1.3 Quality status of livestock and poultry, and aquatic products: the impact of environmental pollution on the growth, development, output, quality of livestock and poultry, fish and shrimp, and the degree and scope of product pollution.
4.2.2 Preparation of sampling materials
4.2.2.1 Tools: silicon knives, stainless steel scissors, stainless steel cutters, sample bags, curling kettles, etc. 4.2.2.2 Stationery: sample labels, record forms, stationery clips, pencils and other small items. 4.2.3 Sample collection
4.2.3.1 Meat sample sampling: For large livestock and poultry (cattle, sheep, etc.), 23 local livestock and poultry should be selected from the food processing plant or food station of the product production base. For small livestock and poultry (chickens, ducks, geese), 3 to 6 livestock and poultry should be selected from the selected professional breeders or farmers. Use a silicon knife (stainless steel knife) to randomly take about 1kg of mixed samples from the back and legs. Immediately freeze and store below 0℃ after collection, and avoid immersion in formalin to avoid metal contamination. Samples of various organ tissues should be collected simultaneously as needed. 4.2.3.2 Egg sample sampling: 1kg of fresh eggs should be randomly selected from the selected farms (or professional breeders). Normal fresh eggs have complete and clean shells, completely white inner shells, no spots or dirt, transparent egg whites, uncracked egg yolks, distinct egg whites and yolks, no blood streaks, and no peculiar smells. 4.2.3.3 Collection of milk samples: Select 4 to 5 livestock and poultry from the selected farms (or professional farmers) to collect whole milk. The samples should be fully mixed and collected after no cream is formed. If cream is formed, the cream should be completely scraped off the wall of the container and stirred until the liquid is evenly emulsified. 4.2.3.4 Collection of aquatic product samples
Select 1kg mixed samples of fresh fish, shrimp, snails, clams, etc. from the selected fish ponds and reservoirs. For those weighing about 500g, the number of individuals should be no less than 5, and for those weighing less than 250g, the number of individuals should be no less than 10. Remove the scales and gills and other inedible parts of the fish, cut it longitudinally along the spine, take half or several parts (for those weighing less than 50g, take the whole), remove the spines, chop and mix. Remove the hard shells of snails, clams and other shellfish, take their muscles (meat tissue), chop and mix. 4.3 Sampling time and frequency
4.3.1 General crop samples are collected when the crops are harvested or synchronously with the soil, and each crop is sampled once. The pollution items that must be tested are once a year, and other items are once every 3 to 5 years.
4.3.2 The sampling time and frequency of livestock, poultry and aquatic products are determined according to the monitoring purpose. 4.3.3 When monitoring pollution accidents, sampling should be carried out immediately after receiving the accident report. 4.3.4 When monitoring for scientific research, sampling can be carried out at different growth stages or depending on the research purpose. 72
4.4 Sampling volume
NY/T 398—2000
The sampling volume is generally 35 times the volume of the sample to be tested, and the volume collected at each point varies with the number of sampling points. Due to the different types of agricultural, livestock and aquatic products and different analysis parts, the sample collection volume and the sample volume to be tested are slightly different. The general sampling volume of samples is: 500g (dry weight sample) for grains, oilseeds, and fruits, 1kg (fresh weight sample) for fruits and vegetables, 500g (dry weight sample) for aquatic plants, tobacco leaves and tea leaves can be collected as appropriate (--generally 2~~3 times the volume of the sample to be tested), and 1kg (fresh weight sample) for meat, egg products and aquatic products. 4.5 Sampling site records
4.5.1 At the same time as sampling, a dedicated person shall fill in the agricultural, livestock and aquatic product label, sampling record, and sample registration form, and summarize them for filing. See Figure 1 for the agricultural, livestock and aquatic product label. See Table A1 and Table A2 in Appendix A for the sampling record and sample registration form. Agricultural, livestock and aquatic product sample labels
Sample number
Sample name
Monitoring items
Sampling location
Sampling person
Business code
Sampling time
Figure 1 Agricultural and livestock product sample labels
4.5.2 Filling personnel shall mark the sampling points on the actual field topographic map according to the distance and orientation of obvious points, and unify the numbers with the record cards and labels.
4.6 Sampling precautions
4.6.1 Pay attention to the representativeness of the samples when sampling. When collecting fruit samples, pay attention to the age, plant type, growth potential, number of fruits, and the location and orientation of the fruits; when poultry, fish and other individuals are large, pay attention to taking samples from different parts. 4.6.2 The sampling time of crops should be collected on a windless and sunny day, and it is not suitable to collect samples after rain. Sampling should avoid pests and diseases and other special plants. If collecting root samples, do not lose the root hairs when removing the soil from the roots. 4.6.3 When collecting samples of plant roots, stems, leaves and fruits at the same time, they should be classified and packaged on site, and the same crop at the same sampling point should use a unified number to avoid confusion.
4.6.4 After fresh samples are collected, they should be immediately put into polyethylene plastic bags and the bag mouth should be tied tightly to prevent moisture evaporation. Livestock and aquatic products should be immediately put into ice pots to keep fresh.
4.6.5 When animal samples need to be analyzed separately for viscera, fat and muscle, viscera, fat and muscle samples should be taken at the same time, and their correspondence should be noted.
4.6.6 For samples for heavy metal determination, try to use stainless steel products to directly collect samples. 4.6.7 Fill in two copies of agricultural, livestock and aquatic product labels, one in the bag and the other tied at the bag mouth. After sampling, each item should be checked on site. If there are missing items, omissions or errors in the sampling record form, sample registration form, sample bag label, agricultural, livestock and aquatic product samples, sampling point map marks, etc., they should be supplemented and corrected in time before leaving the site. 4.7 Sample transportation
4.7.1 Before shipping, the samples must be checked against the sample registration form, sample label and sampling record piece by piece, and then classified and packed after verification. 4.7.2 During transportation, the samples must be strictly prevented from loss, confusion or contamination, and special personnel will be assigned to escort them and deliver them to the laboratory on time. Both the recipient and the sender sign the sample registration form, and each party keeps a copy of the sample record for future reference. 4.7.3 Fresh samples of livestock, poultry and aquatic products must be transported frozen, and special insulated containers can be equipped with refrigerants. Samples with more water should be put into plastic food bags first, and then placed in containers to prevent water loss. 4.8 Sample preparation
4.8.1 Sample preparation work site: There should be an air drying room and a processing room. The room should face the sun (strictly prevent direct sunlight from shining on the sample), be ventilated, clean, dust-free, and free of volatile chemicals.
4.8.2 Sample preparation tools and containers
4.8.2.1 White Tang porcelain plates and wooden plates are used for drying. NY/T 398—2000
4.8.2.2 Small threshers, small shellers, stainless steel knives and scissors, wooden rollers, hard wooden washboards, colorless polyethylene films, etc. are used for threshing, shelling, and chopping.
4.8.2.3 Agate ball mills, agate mortars, white porcelain mortars, stone mills, stainless steel mills, cyclone mills are used for grinding air-dried samples; stainless steel food processors, silicon knives, stainless steel cutters, stainless steel scissors, etc. are used for chopping fresh samples. 4.8.2.4 Use nylon sieve for sieving, with specifications of 20-60 mesh. Fresh samples do not need to be sieved. 4.8.2.5 Use ground-mouth glass bottles with stoppers, colorless polyethylene plastic bottles with stoppers, glass bottles with stoppers, colorless polyethylene plastic bags or special kraft paper bags for packaging. The specifications depend on the quantity.
4.8.3 Sample processing
4.8.3.1 Sample acceptance: The sampling group fills out three copies of the sample delivery form, submits one copy to the sample management personnel and one copy to the processing personnel, and the sampling group keeps one copy. The three parties will start processing the sample only after they have checked and signed. 4.8.3.2 Sample reduction: The monitoring samples must be divided into the main sample and the duplicate sample after reduction. The duplicate samples are classified and stored, and the main sample is processed as required. The specific procedures are as follows:
a) Granular samples such as grains should be reduced by the quartering method. First, thresh the grain sample manually with a small thresher or with a hardwood rub board and hardwood block, mix it repeatedly and evenly, spread it into a circle, draw a cross line through the center line, divide the circle into four equal parts, take two equal parts diagonally, and continue to reduce it to the required number.
b) Block samples such as fruits and large vegetable samples such as Chinese cabbage and cabbage should be reduced by diagonal division. First, wash the sample with clean water and dry it until there is no water, then place it vertically, cut the middle part horizontally, and then cut the upper and lower parts diagonally respectively, remove the inedible part (see Table 1 for the edible part), and take the required amount of samples. c) Small leafy vegetable samples should be reduced by random sampling. First, wash the sample with clean water and dry it until there is no water, then roughly chop the whole plant (see Table 1 for the edible part) and mix it evenly, and randomly take the required amount of samples. Table 1 Edible parts of fruits, vegetables, tobacco and tea samples for monitoring Name of samples
Thin-skinned fruits such as apples and pears
Thick-skinned fruits such as citrus and grapefruit
Tomatoes and eggplants
Radishes and carrots
Chinese cabbage and Chinese cabbage
Tobacco leaves and tea leaves
Parts to be tested
Pulp with skin and peeled flesh without stalks and cores (including seeds) are tested separately1Outer skin and flesh (including inner skin and tendons) are tested separatelyPulp without stalks is tested
Pulp without stalks is tested
Leaves and roots (gently wash the root mud with water and dry it slightly) are tested separatelyRemove roots and remove the outer rotten leaves for testingbzxz.net
Fresh leaves and dry leaves are tested separately
d) Livestock, poultry and aquatic product samples are divided by random sampling method. First, wash the sample with clean water and dry it until it is dry. Remove the skin, bones, scales, thorns and other non-edible parts, cut into thin strips, mix well and randomly take the required amount of samples. Eggs and milk are directly reduced by random sampling. 4.8.3.3 Sample preparation
4.8.3.3.1 Crop samples: There are two processing methods: dry samples and fresh samples. Dry samples are used to determine heavy metal elements and protein, fat and fiber content, etc. Fresh samples are used to determine and analyze volatile organic pollutants (pesticides, phenols, cyanide, etc.). a) Dry sample processing: Grain samples are directly ground after wiping off mud and dust on the samples with dry gauze. Grain samples with skin should be rinsed with clean water, dried, peeled and ground; roots, stems, leaves, fruits, vegetables and fruits should be cut into 0.5-1cm blocks or strips with stainless steel knives or scissors, and spread on the drying tray in the drying room to air dry. To speed up drying, the chopped samples can be placed in an oven at 85-90℃ for 1 hour to destroy the enzyme, and then ventilated and dried at 60-70℃ for 24-48 hours to form air-dried samples. The above two air-dried samples are placed in an agate mortar (or an agate sample crusher, stone mill, stainless steel mill) for manual or mechanical grinding, so that all samples pass through a 40-60 mesh nylon plastic sieve, and are mixed evenly to form the test sample.
NY/T 398--2000
b) Fresh sample addition: For fresh samples, use clean gauze to gently wipe off the sediment and other attachments on the sample. L, then directly use a tissue crusher to crush it, and mix evenly to form the test sample. Samples with more fiber, such as roots, stems, leaves, etc., cannot be crushed by a crusher. They can be cut into small pieces with a stainless steel knife or scissors, and then sieved and mixed to obtain the test sample. 4.8.3.3.2 Animal and animal products: Process fresh samples, a) Meat tissue: crush the sample with a tissue crusher, mix well to obtain the test sample. b) Eggs: peel the fresh eggs of the sample, mix the egg white and egg yolk thoroughly to obtain the test sample (do not bubble). If they are measured separately, knock them into a 7.5-9 cm funnel with the egg yolk on the top and the egg white on the bottom, take them out and mix them well to obtain the test sample. c) Dairy: warm the sample to about 20℃, pour it into a clean container and mix it well to obtain the test sample. If the emulsion oil block has not yet dispersed or the emulsion oil is attached to the container wall, scrape the emulsion oil and warm it to 38℃ in a water bath, mix it well to obtain the test sample. 4.8.3.3.3 Aquatic products: Process fresh samples. Use a tissue pounder to stir the reduced sample into a paste, and mix it evenly to make the sample to be tested. 4.8.3.3.4 Aquatic plant samples: process them into the sample to be tested as vegetable samples. 4.8.3.4 Sample packaging: After grinding and mixing, the samples are packaged in sample bags or sample bottles. Fill in two copies of the agricultural, livestock and aquatic product label (see Figure 1 for the format of the agricultural, livestock and aquatic product label). Put one copy in the bottle or bag and stick one copy on the outside. 4.8.4 Sample preparation precautions
4.8.4.1 During sample preparation, the agricultural, livestock and aquatic product labels and agricultural, livestock and aquatic product samples at the time of sampling are always placed together, and it is strictly forbidden to mix them up. 4.8.4.2 During the entire process of each sample being processed and packaged and sent to the laboratory, the tools used are always consistent with the code of the sample container. 4.8.4.3 The tools used for sample preparation should be scrubbed once after each sample is processed to prevent cross contamination. 4.8.4.4 When monitoring zinc and lead, avoid using rubber tools (rubber, rubber thresher) to avoid contaminating the sample. 4.9 Sample preservation
4.9.1 The preservation of samples should adopt appropriate storage methods according to different objects. Keep for half a year to one year, or after the analysis task is completed and the inspection is correct, if it is not necessary to keep it, it can be discarded.
4.9.2 Dry samples of crops are classified and stored in the sample cabinet of the sample library according to different numbers and particle sizes. The sample library is always kept dry, ventilated, without direct sunlight and pollution.
4.9.3 All fresh samples are stored in refrigerators or low-temperature freezers according to sample categories. The refrigerator is kept clean and free of chemicals. Samples can be stored for 3~~4 days. Samples that need to be stored for a long time should be stored in a -20C low-temperature freezer. 4.9.4 Check samples regularly to prevent deterioration, rodent damage, and sample label shedding. Once problems are found, they should be remedied in time. 4.10 Sample moisture determination
4.10.1 The content of pollutants in melons, fruits, vegetables, etc. is often expressed in fresh weight, and is directly measured with fresh samples without measuring moisture. However, air-dried and crushed samples are often used to determine the total amount of ingredients. When expressed in fresh weight, the moisture content should be measured. The method is as follows: weigh a certain amount of fresh sample before air drying, and weigh it to constant weight after air drying. Calculate the moisture coefficient according to formula (1). Divide the component content calculated by the air-dried sample weight by the moisture coefficient to obtain the component content expressed in fresh weight. Moisture coefficient = sample weight
sample fresh weight
Divide the pollutant content calculated by air weight by the moisture coefficient to obtain the pollutant content expressed in fresh weight. 4.10.2 The content of samples such as grain is measured by air-dried samples and expressed in air-dried weight. It is not necessary to measure the moisture content. 4.10.3 Various air-dried samples should be dried at 65℃ to remove hygroscopic water before measurement and then weighed for measurement. 4.11 Sample number
4.11.1 The sample number of agricultural, livestock and aquatic products consists of a category code and a sequence number. (1)
4.11.1.1 Category code: It is represented by 1 to 2 capital letters of the Chinese pinyin of the keywords of the names of agricultural, livestock and aquatic products, that is, "SD" represents rice and "R" represents meat samples, etc.
4.11.1.2 Sequence number: Arabic numerals are used to represent samples collected from different locations. The sample number starts from R001 and the sequence number is 75
for samples collected from one sampling point.
NY/T 398—2000
4.11.2 For control points and background points, add "CK" after the number. 4.11.3 The number of sample registration and sample operation should be consistent with the number of collected samples to avoid confusion. 5 Monitoring items and analysis methods for agricultural, livestock and aquatic product pollution 5.1 Principles for determining monitoring items
5.1.1 Key items:
a) Pollutants that are required to be controlled in food hygiene standards and residue limit standards; h) Pollutants that are not required to be controlled in food hygiene standards and residue limit standards, but are confirmed to be accumulated in agricultural, livestock and aquatic products based on local environmental pollution conditions (such as agricultural area atmosphere, agricultural irrigation water, etc.), causing agricultural, livestock and aquatic product output to decrease, quality to deteriorate, commodity value to fall, and even inedible.
5.1.2 General items
Determination is selected by local areas. General items generally include the following categories: a) Newly included pollutants that accumulate less in agricultural, livestock and aquatic products; h) Indicators of changes in the characteristics of agricultural, livestock and aquatic products due to environmental pollution; c) Quality indicators of agricultural, livestock and aquatic products. 5.2 Principles for the selection of analytical methods
5.2.1 The first method: the standard method (i.e. arbitration method), which is the analytical method selected from the food hygiene standards and the standards for the allowable values of various pesticide residues.
5.2.2 The second method: the method specified or recommended by the authority 5.2.3 The 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 corresponding general method requirements or the requirements for accurate quantification of the object to be measured. 5.3 Monitoring items and analytical methods
The monitoring items and analytical methods for agricultural, livestock, and aquatic products are shown in Table 2. Table 2 List of crop quality monitoring items and analysis methods Monitoring items
Monitoring instruments
Various types of mercury analyzers
Atomic fluorescence photometer
Spectrophotometer
Atomic fluorescence photometer
Fluorescence spectrophotometer
Atomic fluorescence photometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Atomic absorption spectrometer
Monitoring Test method
Cold atomic absorption spectrometry
Atomic fluorescence spectrometry
Silver salt method
Hydride atomic fluorescence spectrometry
Fluorescence method
Hydride atomic fluorescence spectrometry
Flame atomic absorption spectrometry
Graphite furnace atomic absorption spectrometry
Flame atomic absorption spectrometry
Graphite furnace atomic absorption spectrometry
Flame atomic absorption spectrometry
Method source
GB/T 5009. 17
Standard Manual of Physical and Chemical Inspection of Food Hygiene GB/T 5009.11
Standard Manual of Physical and Chemical Inspection of Food Hygiene GB12399.20
GB12399:20
GB/T 5009.14
GB/T5009.13
GB/T5009.13
GB/T5009.12
GB/T 5009.12
GB/T5009.15
GB/T 5009.15
Monitoring Items
Cyanide
Nitrite
Nitrate
Lys(a)pyrene
Aldrin
Dieldrin
BHC
DDT
Dichlorvos
Phorate
Methoate
Malathion
Parathion
Isocarb
Cypermethrin
Deltamethrin
Cenvalerate
Monitoring Instruments
Atomic Absorption Spectrometer
Oscillopolarograph
Spectrophotometer
Atomic Absorption Spectrometer
Spectrophotometer Spectrophotometer
Ion meter
Spectrophotometer
Spectrophotometer
Spectrophotometer
Spectrophotometer
Fluorescence spectrophotometer
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
Gas chromatograph
NY/T 398 -- 2000
Table 2 (end)
Monitoring methods
Graphite furnace atomic absorption spectrometry
Polarography
Diphenylcarbazide photometry
Graphite furnace atomic absorption spectrometry
Diffusion-fluorine reagent colorimetry
Ashing distillation-fluorine reagent colorimetry
Fluoride ion selective electrode method
Isonicotinic acid pyrazolone photometry
Griess reagent colorimetry
Griess reagent colorimetry
Fluorescence spectrophotometry
Visual inspection
Gas chromatography
Gas chromatograph 6 Quality control and quality assurance of laboratory analysis for monitoring pollution in agricultural, livestock and aquatic products 6.1 For the quality control procedures for routine analysis in the laboratory, see NY/T395.
6.2 Laboratory basics
See NY/T395.
6.3 Laboratory internal quality control
6.3.1 Basic experiments for analytical quality control
Source of method
GB/T14962
GB/T14962
Selected by agricultural sector
GB/T16343
GB5009.18
GB 5009.18
GB5009.18
GB/T5009.36
GB/T 5009. 33
GB/T 5009.33
GB/T 5009.27
GB/T 5009.27
GB/T 5009.36
GB/T5009.36
GB/T5009.36
GB/T 5009.19
GB/T 5009.19
GB/T 5009.20
GB/T 5009.2 0
GB/T 5009. 20
GB/T 5009. 20
GB/T5009.20
GB/T 5009.20
GB/T 5009.20
GB/T14929.4
GB/T14929.4
GB/T 14929. 4
See NY/T 395.
6.3.2 For the drawing, checking and use of calibration curve, see NY/T395.
6.3.3 Precision control
NY/T 398 --2000
6.3.3.1 Determination rate: For all items that can be analyzed in parallel, 10% to 15% parallel samples shall be made for each item of each batch of samples. For less than 5 samples, the rate shall be increased to more than 50%. 6.3.3.2 Determination method: The coded parallel samples compiled by the analyst or the coded parallel samples compiled by the quality control personnel at the sampling site or laboratory are equivalent and do not need to be repeated.
6.3.3.3 Qualification requirement: The error of the parallel double sample determination results is qualified if it is within the allowable error range. The allowable error range is shown in Table 3. For methods that do not list the allowable error, when the uniformity and stability of the sample are good, refer to the provisions of Table 4. When all the parallel double sample determinations are unqualified, the parallel double sample determinations shall be repeated; when the pass rate of the parallel double sample determination is less than 95%, in addition to re-determining the unqualified ones, the determination rate shall be increased by 10% to 20%, and so on until the total pass rate is 95%. Table 3 Precision and accuracy allowable error of parallel double sample determination values for agricultural, livestock and aquatic product monitoring Sample content
Monitoring items
0. 1~~1. 0
Element content range
img/kg
10~100
0. 1~1. 0
Precision
Relative
Standard deviation in room, %
Relative
Standard deviation between rooms, %
Standard recovery rate, %
75～110
85~110
90~105
75～110
85~110
90~~105
90~105
90~105
90~1 05
85~110
85~110
90~105
85~110
85~110
90~105
85~110
85~110
90~105
Accuracy
Relative
Error between rooms, %
Relative
Error between rooms, %
Table 4 Maximum allowable relative deviation of parallel samples for monitoring of agricultural, livestock and aquatic products Maximum allowable relative standard deviation
Range of element content
0. 1~～0. 01
0. 010~0. 001
Applicable analytical methods
Atomic absorption spectrometry
Cold atomic absorption method
Atomic fluorescence method
Atomic fluorescence method
Spectrophotometry
Atomic absorption spectrometry
Atomic absorption spectrometry
Spectrophotometry
Atomic absorption spectrometry
Maximum allowable relative standard deviation
6.3.4 Accuracy control
6.3.4.1 Use of standard samples and quality control samples NY/T 398—2000
In routine analysis, each batch must be accompanied by a pair of parallel quality control samples. Under the premise that the precision of the measurement is qualified, the measurement value of the quality control sample must fall within the range of the quality control sample guarantee value (at a confidence level of 95%), otherwise the results of this batch are invalid and need to be re-analyzed. 6.3.4.2 Determination of spike recovery rate
When there is no standard substance or quality control sample for the selected item, a spike recovery experiment can be used to check the accuracy of the measurement. a) Spike rate: In a batch of samples, 10% to 20% of the samples are randomly selected for spike recovery determination. When the number of samples is less than 10, the spike ratio should be appropriately increased. In each batch of the same type of samples, the number of spiked samples should not be less than 1. b) Spike amount: The spike amount depends on the content of the component to be measured. For high content, 0.5 to 1.0 times, add 2 to 3 times for low content, but the total amount of the measured component after spike addition shall not exceed the upper limit of the method. The spike concentration should be high and the volume should be small, and should not exceed 1% of the original sample volume.
c) Qualification requirements: The spike recovery rates of agricultural, livestock and aquatic product monitoring should be qualified if they are within the allowable range of spike recovery rates. The allowable range of spike recovery rates is shown in Table 3. When the spike recovery qualified rate is less than 70%, the recovery rate of the unqualified ones shall be re-determined, and 10% to 20% of the samples shall be added for spike recovery rate determination until the total qualified rate is greater than or equal to 60%. 6.3.5 Quality control charts and others
See NY/T 395.
6.3.6 Treatment of interference during monitoring See NY/T 395.
6.4 Quality control between laboratories
See NY/T395.
7 Mathematical statistics for monitoring of pollution of agricultural, livestock and aquatic products7.1 Experimental records
See NY/T395.
7.2 Data processing of laboratory analysis results
See NY/T395.
7.3 Representation and reporting of analysis results
See NY/T 395.
7.4 Statistics of monitoring results of agricultural, livestock and aquatic productsa) See Table A3 in Appendix A for the monitoring results of pollution of agricultural, livestock and aquatic products; b) See Table A4 in Appendix A for the statistical table of monitoring results of pollution of agricultural, livestock and aquatic products.8 Evaluation of monitoring results of pollution of agricultural, livestock and aquatic products8.1 Evaluation unit
8.1.1 Basic evaluation unit: agricultural and livestock product monitoring unit. 8.1.2 Statistical evaluation unit: According to the needs of the analysis of the quality status of agricultural, livestock and aquatic products, each sampling point shall be classified and statistical evaluation shall be carried out according to the category.
8.2 Evaluation Standards
8.2.1 Food hygiene standards and residue limit standards are used as evaluation standards. 8.2.2 For items without quality standards, the pollutant accumulation index can be calculated using the pollutant background value for comparison and explanation. 79
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