GB/T 27856-2011 Aerobic and anaerobic transformation test of chemicals in soil GB/T27856-2011 |tt||Standard compression package decompression password: www.bzxz.net
This standard specifies the terms and definitions, test material information, test principle, reference material, test method overview, test procedure, quality assurance and quality control, data and report of the aerobic and anaerobic transformation test of chemicals in soil. This standard is used to evaluate the aerobic and anaerobic transformation of chemicals in soil; to determine the transformation rate of chemicals under the action of plants and soil microorganisms, as well as the properties and generation rate of the transformation products and the degradation rate [1-9]. This standard is applicable to all chemicals with low volatility, water soluble or water insoluble, and can be accurately measured (including radioactive labeled or non-labeled substances). This standard is not applicable to chemicals that are volatile in soil and cannot be retained in soil under the test conditions.
This standard was drafted in accordance with the rules given in GB/T1.1-2009.
The technical content of this standard is the same as that of the OECD Guidelines for Testing Chemicals No. 307 (2002) "Aerobic
and Anaerobic Transformation in Soil" (English version).
This standard has been modified in the following structural and editorial aspects:
——— The measurement units are changed to the legal measurement units of China.
——— To be consistent with the existing standard series, the name of the standard is changed to "Aerobic and Anaerobic Transformation Test for Chemicals in Soil". ———
The informative part of the introduction of OECD No. 307 (2002) "Aerobic and Anaerobic Transformation in Soil" is deleted. ———
The original "Test Material Data" section provides reference test methods for five physical and chemical indicators. Among them, the nine test methods of six indicators have corresponding Chinese standards: GB/T21845 "Test for water solubility of chemicals", GB/T21852 "Test for chemical partition coefficient (n-octanol-water) by high performance liquid chromatography", GB/T21853 "Test for chemical partition coefficient (n-octanol-water) by shake bottle method", GB/T21855 "Test for hydrolysis of chemicals related to pH", GB/T22052 "Method for determining the relationship between vapor pressure and temperature and initial decomposition temperature of liquids by liquid vapor pressure meter", GB/T22228 "Static method for determining the vapor pressure of solids and liquids for industrial chemicals in the range of 10-1Pa to 105Pa", GB/T22229 "Static method for determining the vapor pressure of solids and liquids for industrial chemicals in the range of 10-3Pa to 10-1Pa", GB/T22228 "Static
method for determining the vapor pressure of solids and liquids for industrial chemicals in the range of 10-1Pa to 105Pa", GB/T22229 "Static method for determining the vapor pressure of solids and liquids for industrial chemicals in the range of 10-3Pa to 10-3Pa", GB/T22052 "Method for determining the relationship between vapor pressure and temperature and initial decomposition temperature of liquids by liquid vapor pressure meter", GB/T22228 "Static method for determining the relationship between vapor pressure and temperature of solids and liquids for industrial chemicals in the range of 10-1Pa to 105Pa", GB/T22229 "Static method for determining the relationship between vapor pressure and temperature of solids and liquids for industrial chemicals in the range of 10-3Pa to 10-3Pa", GB/T22052 "Method for determining the relationship between vapor pressure and temperature of solids and liquids for industrial chemicals in the range of 10-1Pa to 105Pa", GB/ Pa to 1Pa Determination of Vapor Pressure Balance Method", GB/T27854-2011 "Chemical Soil Microbial Nitrogen Transformation Test" and GB/T27855-2011 "Chemical Soil Microbial Carbon Transformation Test". These nine Chinese standards, together with OECD Chemical Testing Guide No. 104 "Vapor Pressure" and OECD Chemical Testing Guide No. 112 "Dissociation Constant in Water" are the normative reference documents of this standard.
——— "Main transformation products" (see 3.12) are added to the terms and definitions. ———
The informative appendix NA "Main physical and chemical properties of different types of soils in different regions of China" is added.
This standard is proposed and coordinated by the National Technical Committee for Standardization of Hazardous Chemicals Management (SAC/TC251).
Drafting units of this standard: Chemical Registration Center of the Ministry of Environmental Protection, Nanjing Institute of Environmental Sciences of the Ministry of Environmental Protection, Chinese Research Academy of Environmental Sciences, Guangdong Microbiological Analysis and Testing Center, Shanghai Research Academy of Environmental Sciences.
The main drafters of this standard are: Liu Chunxin, Yang Li, Chen Lin, Shan Zhengjun, Wang Lei, Li Handong, Li Ji, Huang Xing, Mei Chengfang.
The following documents are indispensable for the application of this document. For any dated referenced document, only the dated version applies to this document
. For any undated referenced document, the latest version (including all amendments) applies to this document.
GB/T21845 Test for water solubility of chemicals
GB/T21852 Test for partition coefficient of chemicals (n-octanol-water) by high performance liquid chromatography
GB/T21853 Test for partition coefficient of chemicals (n-octanol-water) by shake flask method
GB/T21855 Test for hydrolysis of chemicals related to pH
GB/T22052 Method for determining the relationship between vapor pressure and temperature and initial decomposition temperature of liquids by liquid vapor pressure gauge
GB/T22228 Determination of vapor pressure of solids and liquids for industrial chemicals in the range of 10-1 Pa to 105 Pa - Static method
GB/T22229 Determination of vapor pressure of solids and liquids for industrial chemicals in the range of 10-3 Pa to 1Pa - Vapor pressure equilibrium method
GB/T27854 Test for nitrogen transformation of chemicals by soil microorganisms
GB/T 27855 Test for carbon transformation of chemicals by soil microorganisms
OECD Guidelines for Testing Chemicals No. 104 Vapour Pressure
OECD Guidelines for Testing Chemicals No. 112 Dissociation Constants in Water
Foreword III
Introduction IV
1 Scope 1
2 Normative references 1
3 Terms and definitions 1
4 Information on test substance 3
5 Principle of the test 3
6 Reference material 3
7 Overview of the test method 3 8
Test procedure 5
9 Quality assurance and quality control 8
10 Data and report 8
Appendix A (Informative Appendix) Water tension, field capacity (FC) and soil water holding capacity (WHC) 11
Appendix B (Informative Appendix) Soil moisture of different types in different countries 12
Appendix C (Informative Appendix) Example of test device 13
Appendix NA (Informative Appendix) Main physical and chemical properties of different types of soil in different regions of China 14
References 15

[CS13.300;13.020.40
National Standard of the People's Republic of China
GB/T27856—2011
Chemicals-Aerobic and anaerobic transforration in soil tes2011-12-30 Issued by
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2012-08-01 Implementation
1 Scope
2 Normative references
Terms and definitions
Information on test substance
Test principle
Reference substance
Overview of test method
8 Test procedure
Quality assurance and quality control
10 Data and report:
Appendix A (informative) Water tension, intermediate water holding capacity (FC) and soil water holding capacity (WHC)Appendix B (informative) Soil moisture of different types in different countriesAppendix (informative) Example of test apparatusAppendix NA (informative) Main physical and chemical properties of different types of soil in different regions of ChinaReferences
TTKANTKACA
GB/T 27856-2011
TTTKAONTKACA
This standard was drafted in accordance with the rules given in GB/T1.1-2009. GB/T27856-2011
The technical content of this standard is the same as that of the OECD Guidelines for the Testing of Chemicals No. 307 (2002) Aerobic and Anaerobic Transformation in Soil (English version). This standard has made the following structural and editorial changes: 1. The measurement units are incorporated into the legal measurement units of my country. 2. In order to be consistent with the existing standard series, the name of the standard is changed to "Test for Aerobic and Anaerobic Transformation of Chemicals in Soil". The informative part of the introduction to OECD No. 307 (2002) Aerobic and Anaerobic Transformation in Soil is deleted. The original text "Test Material Data" provides reference test methods for five physical and chemical indicators. Among them, the nine test methods for six indicators have corresponding Chinese standards: GB/T21845 Chemical Water Solubility Test, GB/T2152 Chemical Partition Coefficient (n-octanol-water) High Performance Liquid Chromatography Test, GB/T21853 Chemical Partition Coefficient (n-octanol-water) Shake Bottle Test, GB/T21855 Chemical Hydrolysis Test Related to PH, GB/T22052 Dual-purpose Liquid Vapor Pressure Gauge GB/T22228 Determination of vapor pressure of solid and liquid industrial chemicals in the range of 10-1Pa to 105Pa - Static method, GB/T22229 Determination of vapor pressure of solid and liquid industrial chemicals in the range of 10-Pa to 1Pa - Vapor pressure equilibrium method3, GB/T27B54-2011 Chemical soil microbial transformation test and GB/T27855-2011 Chemical soil microbial carbon transformation test. These nine Chinese standards, together with OECD Chemical Testing Guide No. 104 Vapor Pressure Test and OECD Chemical Testing Guide No. 112 Dissociation Constant in Water3, are used as normative reference documents of this standard. - "Main transformation products" are added to the terms and definitions (see 3.12). - An informative appendix NA "Main physical and chemical properties of different types of soils in different regions of my country" is added. This standard is proposed and managed by the National Technical Committee for the Promotion of Hazardous Chemicals Management Standards (SAC/TC251). This standard was drafted by: Chemical Registration Center of the Ministry of Environmental Protection, Nanjing Institute of Environmental Sciences of the Ministry of Environmental Protection, Chinese Academy of Environmental Sciences, Guangdong Microbiological Analysis and Testing Center, Shanghai Academy of Environmental Sciences. The main drafters of this standard are Liu Chunxin, Yang Li, Chen Lin, Shan Zhengjun, Tu Lei, Li Handong, Li Nong, Huang Xing, Mei Chengfang. TTTKANYKACA
GB/T27856—2011
This test method is used to evaluate the aerobic and anaerobic transformation of chemical substances in soil. This test is used to determine (i) the transformation rate of the test substance, and (ii) determine the nature of the transformation products that may be exposed to plants and soil microorganisms and their generation rate and degradation rate. The test objects of this test are those chemical substances that are directly applied to the soil or are likely to enter the soil environment. The results of such laboratory studies can also provide sampling and analysis plans for research in related fields. The evaluation of the transformation pathway of the test substance only uses one soil for aerobic and anaerobic transformation studies, while the transformation rate of the test substance should be studied and determined using more than three other soils. The test soil type should be representative of the environmental conditions in which the test substance is used and released. For example, chemicals that may be released into subtropical and tropical soils should be treated using the Ferrasols or Nitosols method (FAO system). This method can also be used with hydrophilic soil. TTKANYKACA
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Test for aerobic and anaerobic transformation of chemicals in soil GB/T 27856—2011
This standard specifies the terms and definitions, test substance information, test principle, reference substances, test method overview, test procedures, quality assurance and quality control, data and reports for the test for aerobic and anaerobic transformation of chemicals in soil. This standard is used to evaluate the aerobic and anaerobic transformation of chemicals in soil and to determine the transformation rate of chemicals under the action of plants and soil microorganisms, as well as the properties and generation rate of transformation products and degradation rates [1-Ting]. This standard is applicable to all chemicals (including radioactive markers and non-markers) that are low in volatility, water-soluble or water-insoluble and can be accurately measured.
This standard is not applicable to chemical substances that are volatile in the soil and cannot be retained in the soil under the test conditions. 2 Normative references
The following documents are essential for the application of this document. For all references with dates, only the versions with dates apply to this document. For all references without dates, the latest versions (including all amendments) apply to this document. GB/T21845 Test for water solubility of chemicals
GB/T21852 Test for partition coefficient of chemicals (n-octanol-water) by high performance liquid chromatography GB/T21853 Test for partition coefficient of chemicals (n-octanol-water) by shake flask GB/T 21855
Test for hydrolysis of chemicals in relation to pH Method for determining the relationship between vapor pressure and temperature of liquids and the initial decomposition temperature by using a liquid vapor pressure gauge GB/T22052
GB/T 22228
GB/T 22229
Determination of vapor pressure of industrial chemicals solids and liquids in the range of 10-1Pa to 10°Pa, static method Determination of vapor pressure of industrial chemicals solids and liquids in the range of 10'Pa to 1Pa Vapor pressure leveling of chemicals Test for nitrogen transformation by soil microorganisms
GB/T 27854
GB/T 27855 Test for carbon transformation by soil microorganisms of chemicalsOECD Guide for Testing of Chemicals No. 104 Vapor Pressure (Vapaur Pressure)OECD Guide for Testing of Chemicals No. 112 Dissociation Constants in Water (Dissociation Constants in Water)3 Terms and Definitions
The following terms and definitions apply to this document. 3.1
Test substance
Substance of interest, including parent substance or related transformation products. 3.2
Transformation productsAll substances formed by biotic and abiotic transformation of the test substance, including products in bound residues1
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GB/T 27856—2011
Bound residues
Compounds that still exist in the form of parent substance or metabolites in soil, plants and animals after extraction. The extraction method cannot substantially change the structure of the compound. The nature of the binding can be determined to some extent by varying the extraction method and analytical techniques. For example, covalent bonds, ionic bonds, adsorptive binding and inductive effects can be identified by this method. The formation of binding residues usually leads to a significant reduction in bioavailability and bioavailability [L1.3.4
Aerobic transformationReactions that occur in the presence of molecular oxygen\]. 3.5
Anaerobic transformationReactions that occur in the absence of molecular oxygen! 1.3.6
Soil
A mixture of minerals and organic matter, including macromolecules with high carbon and nitrogen content, which contain small living organisms (mostly microorganisms).
Note: Soil fill can be treated in the following two states: 1) Original soil, which forms fill layers with different characteristics over time; 2) Disturbed soil, which is soil that is disturbed during tillage or excavation for sampling [73.7
Mineralization
The complete degradation of an organic compound into CO2 and H2O under aerobic conditions and into CH4, CO2 and H2O under anaerobic conditions.
Note: Under the test conditions of this standard, if compounds marked with \℃ are used, mineralization refers to the oxidation of carbon atoms marked with \C and the release of a certain amount of \CO2.
Half-life: 5
The time required for 50% conversion of the test substance when the conversion can be described by the law of first-order reaction kinetics. Note: The half-life of the test substance is independent of its concentration. 3. 9
50% decay time
disappearance time 50, DTs
The time taken for the concentration of the test substance to decrease by 50%. Note: When the transformation does not conform to the law of first-order reaction kinetics, it is not equivalent to the half-life. 3. 10
75% decay time disappearancetime75, DTrgThe time taken for the concentration of the test substance to decrease by 75%. 3.11
90% decay time disappearancetime90, DTThe time taken for the concentration of the test substance to decrease by 90%. 3.12
major transformatlon productThe transformatlon product whose concentration reaches or exceeds 10% of the added dose of the test substance during the test. 2
4 Information of test substance
4.1 Information of test substance includes:
a) Solubility in water (GB/T21845):131b) Solubility in organic solvents;
GB/T 27856-2011
Vapor pressure (GB/T22052, GB/T22228, GB/T22229 and OECDNo.104)al and Henry band numberc
n-Octanol-water partition coefficient (GB/T21852 and GB/T21853)T:d
Chemical stability in the dark (hydrolyzability) (GB/T21855)121c)
Dissociation constant PK, value (OECDNo.112) (For test substances that are easily protonated or deprotonated, this constant should be known:\3-). 4.2 Other information includes
toxicity data of the test substance to microorganisms (see GB/T27854 and GB/T27855) [13], a) Www.bzxZ.net
b) qualitative and quantitative analysis methods of the test substance and transformation products (including extraction and purification methods). 5 Principle of the test
Under laboratory conditions (constant temperature and humidity), the soil added with the test substance is cultured in a static bioreactor or dynamic flow system in the dark. After an appropriate period of time, the parent substance and transformation products in the soil are extracted and analyzed. The volatile products are absorbed by an appropriate absorption device and their content is determined. The test substance is labeled with 1C, and the generated 1CO: is analyzed. Based on the mass balance, the different mineralization rates of the test substance are determined, and the structure of the combined residue is determined. 6 Comparative substances
Reference substances should be used when characterizing and/or identifying the transformation products by optical and chromatographic analysis. 7 Overview of the test method
7.1 Instruments and equipment
The instruments and equipment used in the test are as follows;
The culture device includes a static closed system or an appropriate flow system 3, 14]. For example, the dynamic flow soil culture device shown in Figure C.1 of Appendix C and the static closed biometer culture device shown in Figure C.2; analytical instruments, gas chromatograph (GC), high performance liquid chromatograph (HPLC), thin layer chromatograph (TLC), mass spectrometer (MS), gas chromatograph-mass spectrometer (GC-MS), high performance liquid chromatography-mass spectrometer (HPLC-MS) and nuclear magnetic resonance (NMR) for chemical analysis of the test substance and transformation products, as well as instruments and equipment for detecting radioactive isotope tracers Labeled, unlabeled test substances and detection systems for the anti-isotope dilution method; liquid scintillation instrument and oxidizer for oxidizing radioactive substances; c
centrifuge;
extraction apparatus (for example, cold extraction centrifuge tubes and Soxhlet extraction apparatus for continuous extraction under reflux); e
condensation apparatus (for example, rotary evaporator); f
g) water bath;
mechanical stirring device:
standard laboratory equipment and glassware for physical and chemical analysis and biological detection. 3
GB/T 27856—2011
7.2 Chemical reagents
The chemical reagents used in the test are as follows;
a) NaOH (analytical grade): 2 mol/L, or other suitable alkaline reagents (KOH and ethanolamine); b) H2SO4 (analytical grade): 0.05ol/L
Ethylene glycol (analytical grade)
Solid absorption materials, such as alkali carbamide and urea; organic solvents (analytical grade), such as acetone and methanol; e)
f) scintillation fluid.
7. 3 Addition of test substances
7.3.1 Addition of test substances to soil in liquid form The test substances can be dissolved in deionized water or distilled water and sprayed into the test soil sample to make the test substances dispersed evenly in the soil. Try not to use co-solvents. However, for test substances with poor water solubility, acetone6 and other auxiliary agents that have little effect on the microbial activity of soil can be appropriately selected, and the amount used should be as small as possible. The test substances should be fully soluble and stable in these auxiliary solvents. Before the formal test, this solvent should be evaporated from the soil.
Solvents that inhibit microbial activity, such as oxadiazine, dichloromethane and other halogenated organic solvents should be avoided. It is usually not appropriate to use preparations of test substances, but for test substances with poor solubility, preparations can be appropriately selected. 7.3.2 The test substance can be added to the soil in solid form. The test substance can be mixed with quartz sand, or with a small amount of air-dried or sterilized test soil subsample, and then mixed evenly with the test soil. If the test substance is dissolved in a solvent and then added to the soil subsample, the solvent should be evaporated first, and then the soil subsample should be added to the original non-sterile soil.
For common chemical substances that enter the soil primarily through sewage sludge or agricultural applications, the test substance should first be added to the sludge and then introduced into the soil sample (see 8.2.1). 7.4 Test soils
7.4.1 Selection of soils
7.4.1.1 To determine the transformation pathway of the test substance, a representative soil may be used: sandy loam, silt loam, soil or fill sand (1), with a pH of 5.5 to 8.0, an organic carbon content of 0.5% to 2.5%, and a microbial biomass of at least 1% of the total organic carbon content (10).
7.4.1.2 To study the transformation efficiency of the test substance, at least two other representative soils should be selected. These soils should differ in organic carbon content, pH, clay content, and microbial content [10]. 7.4.1.3 The test soil type should be representative of the environmental conditions into which the test substance will be applied and released. Paddy soil may also be used. 7.4.1.4 All soil samples should be characterized for texture (% sand, silt, clay), pH, cation exchange capacity, organic carbon content, bulk density, soil water retention, and microbial biomass (aerobic studies only) [16]. 7.4.1.5 Soil water retention may be determined by field capacity (FC), water holding capacity (WHC), or water tension (PF). See Appendix A for solutions.
7. 4. 1. 6
Microbial biomass may be determined by substrate-induced respiration [21-22] or by alternative methods [1F-. 4
7.4,2 Collection, treatment and storage of soil fill
7.4,2.1 Soil collection site
CB/T 27856—2011
Soil collection sites should be selected with detailed information such as exact location, vegetation cover, application of chemical substances, application of organic and inorganic fertilizers and biofertilizers, and other pollutants. Soil that has been applied to the test substance or substances with chemical structures similar to the test substance within four years cannot be used [10.121. If the soil is frozen or covered with a thick layer of snow in winter, soil sampling is difficult, and soil covered with vegetation in the greenhouse (grassland or grass-clover mixed site) can be collected. 7. 4. 2.2 Soil collection and treatment
If it is not water-free soil, avoid sampling during or immediately after long periods of flat ground, frost and flooding (>30 days) i12. Collect fresh soil (within 20 cm below the soil surface) with a moisture content that is easy to screen and treat it as soon as possible. Pick out animal and plant remains and stones first, then pass the soil sample through a 2mm sieve to remove small stones, plant roots and other debris. Avoid excessive drying and rolling before screening the soil fill. It can be packed in open polyvinyl chloride and placed in a dark and ventilated place during transportation to minimize the change of soil moisture content. 7, 4. 2.3 Soil storage
If the test cannot be carried out immediately after collection, the conditions for short-term storage of soil samples should be strictly controlled to maintain microbial activity. Generally, the maximum storage time of soil samples at 4±2℃ is three months [8.10,13.3-4]. 7.4.2.4 Pre-culture of soil fill
Before the formal test, the soil should be pre-cultured to allow the seeds to germinate and remove the seeds. The metabolic balance of the microorganisms is re-established based on the changes in the soil fill from the nesting or storage state to the culture state. The pre-culture time is 2 days to 28 days, and the temperature and mixing degree are close to the actual test conditions [121. The total storage and pre-culture time should not exceed three months. 7.5 Labeling of test substances
The chemical purity and/or radiochemical purity of the test substance should reach more than 95%. Radioactive isotope tracer atoms can be used to label or unlabeled test substances to determine the conversion rate. If the transformation pathway is studied and the mass balance is established, labeled substances should be used for tracing. It is recommended to use C tracer atoms as labels. Isotope atoms such as C, N, H, and P can also be used as labels. The tracer atoms should be labeled at the most stable part of the molecule as much as possible. If the test substance contains a ring, the tracer atoms should be labeled on this ring; if the test substance contains two or more rings, the effect of labeling on each ring should be studied separately to obtain information on the formation of transformation products. 7.6 Control group
The soil fill control group samples without the test substance are cultured under the same conditions (aerobic) as the soil fill samples to be tested with the test substance. The biomass of these control group samples is measured during and at the end of the test. If organic solvents are used when the test substance is added to the soil, the soil control group samples should be added with the same amount of solvent as the soil samples to be tested, and cultured under the same conditions (aerobic). The biomass of these samples is measured at the beginning, during and at the end of the test to detect the effect of organic solvents on microbial biomass.
8 Test Procedure
8.1 Test Conditions
8.1.1 Test Temperature
During the entire test period, the soil should be protected from light and incubated at a constant temperature. The incubation temperature should be representative of the climatic characteristics of the test substance in use and release. In temperate climates, the recommended test temperature for all test substances is 20°C ± 2°C. The temperature should be controlled throughout the test period. For chemicals used or released in colder climates (e.g., autumn/winter in some northern regions), another set of soil samples should be incubated in parallel at a lower temperature (e.g., 10°C ± 2°C). 8.1.2 Humidity
During the aerobic conversion test, the soil moisture should be adjusted to maintain the water tension pF value between 2.0 and 2.5. The soil should not be too wet or too dry to maintain the nutrient content of the food carrier system and microorganisms. Appendix B gives typical soil properties of 9 types in different countries. Appendix NA gives the main physical and chemical properties of 13 typical soil types in my country. Water content should be expressed as the mass of water contained in each kilogram of dry soil, and soil moisture should be controlled by weighing the culture bottles regularly (e.g. every 2 weeks) and adding water (preferably sterile filtered tap water) to compensate for the lost mass. In the process of increasing humidity, the loss of the test substance and/or transformation products due to volatilization and/or photodegradation (if any) should be prevented or reduced.
For transformation tests under aerobic and rice conditions - water overflow should be added to saturate the soil with water. 8.1.3 Aerobic culture conditions
Aerobic conditions mainly exist in the topsoil and sub-topsoil. In a dynamic flow system, aerobic conditions are simulated by purging with humid air or continuously passing humid air. In static bioreactors, air is exchanged by diffusion to maintain aerobic conditions. 8.1.4 Sterile aerobic conditions
To obtain information on abiotic transformation of the test substance, the soil may be sterilized [13:25], the sterile test substance added (e.g., solution added through a sterilizing filter) and humidified sterile air introduced as described in 8.1.3. For hydrophilic soil, the soil and water should be sterilized and incubated as described in 8.1.6. 8.1.5 Anaerobic incubation conditions
The soil should be exposed to the test substance and incubated under aerobic conditions for 30 days or one 0.5, or one DTs (the shorter of the three), and then water should be added to maintain a 1 cm to 3 cm immersion layer to establish and maintain an anaerobic environment. Dynamic flow incubation systems should be purged with an inert gas such as argon or argon. The test system should be capable of measuring pH, oxygen concentration, and redox potential, and be equipped with equipment to collect volatile products. The static biometer culture device should be airtight to prevent air from entering. 8.1.6 Paddy Soil Culture Conditions
To study the transformation of the test substance in paddy soil, pre-culture should be carried out for at least 2 weeks before the transformation test, and the seeds should be removed. The soil depth is at least 5 ctm. During the test, the soil water layer depth is maintained at 1 cm to 5 cm, and the test substance should be added to the water phase. Aeration is carried out with air under aerobic conditions. Monitor and report the pH value, oxygen concentration and redox potential of the water layer. 8.1.7 Test Duration
Rate and transformation pathway tests are usually not more than 120 days:\51. If the aerobic test has obviously completed the final transformation pathway and complete mineralization before 120 days, the test can be terminated earlier. The test can also be terminated after 120 days, or when at least 90% of the test substance is converted and the CO formed exceeds 5% of the theoretical CO value of the test substance. The duration of the test for the formation and degradation characteristics of the test substance and the major transformation products may exceed 120 days and may be up to 6 or 12 months.
8.2 Subdivision of the test substance
8.2.1 Subdivision method 1
Add approximately 50 g to 200 g of soil (middle weight) to each culture bottle (see Figures C.1 and C.2 in Appendix C) and uniformly add the test substance to the soil sample as described in 7.3. Stir or shake the test substance and soil thoroughly with a spatula. After adding the test substance under water-drying conditions, the sample should be mixed thoroughly with water. Analyze the test substance content in the soil (e.g. 1) after a small amount of treatment to determine the uniformity of the test substance in the soil. Other possible methods are as follows:
If the test substance is a plant protection product, the treatment rate is consistent with the highest application rate recommended in its instructions for use and consistent with the depth of soil mixing (for example, the top 10 cm of soil). Note: The initial concentration of an area can be calculated using the equation: AX105
C-1. Initial concentration in soil fill, milligrams per kilogram (mg/kg) A-application rate, dry grams per square meter (kg/m) l-soil thickness, meters (m);
d-soil dry bulk density, kilograms per cubic meter [kg/m\) The typical application rate of 100 mg/n (equivalent to 1 kg per cubic meter) is 1 mg/kg for a foliar or soil-applied chemical in the 10 cm soil layer (assuming a soil bulk density of 1g/cm).
For example, for foliar or soil-applied chemicals that are not mixed with soil, the amount of test substance added to each bottle is related to the depth, which is 2. and cI in this test. For compounds that are mixed with soil, the soil mixing depth specified in the instructions for use shall be used. For general chemical substances, the addition rate should be evaluated based on the primary pathway for entry into soil. For example, if the primary pathway for entry of the chemical into soil is through sewage sludge, the test substance should be added to the sludge at a concentration that reflects the expected concentration of sludge, and the amount of sludge added to the soil should reflect the normal concentration of sludge added to field soil. If this concentration is insufficient to determine the primary transformation product of the test substance, culture another soil sample containing a higher proportion of the test substance as a backup, but avoid excessive transformation products that affect the function of soil microorganisms (see 4.2 and 7.3.1).
8.2.2 Packaging method 2
For larger quantities (1kg to 2kg) of soil samples, the soil can be batch treated with the test substance, that is, the soil sample is placed in a blender and mixed evenly, and then dispensed into culture bottles.The mass of the sample in each culture bottle is 50g~200g. Sample 1B is extracted from the treated batch soil sample to analyze the uniformity of the test substance distribution. Note that this process is very important to ensure that the test substance is evenly distributed in the soil. The test device for the treated soil can be a dynamic flow system as shown in Figure C.1, or a static biometer culture device as shown in Figure C.2 (see Appendix C).
8.3 Sampling and detection
Sampling is performed at a certain interval. Each time, a group of two parallel bottles of soil samples are collected and extracted with solvents of different polarities to analyze the content of the test substance and/or transformation products. In addition, during and at the end of the treatment of each soil sample, the absorption solution or the surrounding absorption material should be collected at different intervals (7 days in the first month, 14 days after the first month) and analyzed for the content of volatile substances. In addition to the soil sample taken directly after the addition of the test substance (0d sample), at least five other sampling points should be selected. The test time interval should be selected according to the degradation mode of the test substance and the degradation and generation mode of the transformation products (for example, interval 0d, 1d, 3d, 7d, 11d, 21d; one month, two months, three months, etc.).
If the test substance is labeled with a radioactive substance, the radioactivity that cannot be extracted is determined by combustion determination, and the mass balance is calculated for each sampling.
Under anaerobic and hydrophilic field culture conditions, the test substance and transformation products are separated from the soil and water phases, or the water phase and soil are separated by filtration or centrifugation before extraction and analysis.
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