Some standard content:
ICS13.300;13.020.40
National Standard of the People's Republic of China
GB/T 27853—-2011
Chemicals
Aerobic and anaerobic transformationin aguatic sediment systens test2011-12-30 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on August 1, 2012
GB/T 27853—2011
Normative reference documents
Terms and definitions
Information on test substance
Test principle
Reference substance
Overview of test method
Test procedure
Quality assurance and quality control
Data and report
Appendix A (informative) Description of aerobic and anaerobic test systems Appendix B (informative)
Appendix C (informative)
Appendix D (informative records)
References
Example of gas flow culture test device
Example of biometer culture device
Example of calculation of additive dosage in test container TTKONKAA
This standard was drafted according to the rules given in GB/T 1.1—2009. GB/T 278532011
This standard is consistent with the technical content of the Organization for Economic Cooperation and Development (OECD) Chemical Testing Guidelines No. 308 (2002) "Aerobic and Anaerobic Transformation in Water-Sediment Systems" (English version). This standard has made the following structural and editorial changes: · The measurement unit is changed to the legal unit of my country. In order to be consistent with the existing standard series, the standard name is changed to "Aerobic and Anaerobic Transformation Test in Water-Sediment Systems for Chemicals" and the information part of the original OECD No. 308 (2002) introduction is deleted; - The original "Test Material Data\" part gives reference test methods for six physical and chemical indicators. Among them, the eight test methods for five indicators have corresponding national standards of my country: GB/T21845 "Chemicals: Water Solubility Test\, G B/T21851 "Batch Balance Method for Chemical Adsorption/Desorption Test", GB/T21852 "High Performance Liquid Chromatography Test for Chemical Partition Coefficient (n-octanol-water)", GB/T21853 "Shake Bottle Test for Chemical Partition Coefficient (n-octanol-water)", 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 Degree of Liquids by Volume Vapor Positron", GB/T22228 "Static Method for Determining Vapor Pressure of Solid and Liquid Industrial Chemicals in the Range of 10-1Pa to 105Pa", GB/T22229 "Vapor Pressure Balance Method for Determining Vapor Pressure of Solid and Liquid Industrial Chemicals in the Range of 10-1Pa to 1Pa". These eight Chinese standards and OECD Chemical Testing Guide No. 104 Vapor Pressure and OECD Chemical Testing Guide No. 112 Dissociation Constant in Water are used as normative reference documents for this standard.
This standard is proposed and managed by the National Technical Committee for Standardization of Hazardous Chemicals Management (SAC/TC251). The drafting units of this standard are: Chemical Registration Center of the Ministry of Environmental Protection, Nanjing Institute of Environmental Sciences of the Ministry of Environmental Protection, Shanghai Testing Center, Shanghai Academy of Environmental Sciences, Safety Evaluation Center of Shenyang Institute of Chemical Industry, and China Chemical Economic and Technological Development Center. The main drafters of this standard are: Liu Chunxin, Yang Li, Zhou Hong, Shi Lili, Liu Jining, Yin Haowen, Yang Jing, Huang Ken, Zhu Jiang, and Shang Xiaobing. 1
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GB/T 27853—2011
Chemicals enter shallow or deep surface waters through direct use, spray drift, runoff, sewer drainage, waste treatment, industrial, urban or agricultural wastewater and atmospheric deposition. This test guide describes a laboratory test method for evaluating the aerobic and anaerobic transformation of organic compounds in water-sediment systems. Chemicals that are directly applied to water or that enter the aquatic environment through the above pathways should be subjected to these studies.
The upper water phase of a natural water-sediment system is generally aerobic, while the surface sediments may be aerobic or anaerobic, but the deeper sediments are usually anaerobic. This article covers all of the above possibilities in aerobic and anaerobic testing. Aerobic tests simulate aerobic water above an aerobic sediment layer, below which is a gradient anaerobic layer. Anaerobic tests simulate a completely anaerobic permanent-sediment system. If there are significant deviations from the environmental conditions, such as the use of intact sediment cores or sediments that have been exposed to the test substance, other methods should be used for testing.
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1 Scope
Aerobic and anaerobic transformation test in water-sediment system of chemicals
GB/T27853—2011
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 aerobic and anaerobic transformation test in water-sediment system of chemicals. This standard is applicable to all chemicals (including radioactive markers or non-radioactive markers) that are low-volatile or volatile, water-soluble or non-water-soluble and can be accurately measured. This standard is applicable to the evaluation of the transformation of chemicals in water and sediments, and is also applicable to estuary/seawater systems. This standard is not applicable to chemicals that are easily volatile in water and cannot be retained in water and/or sediments under the test conditions. This standard is not applicable to simulated flowing water (such as rivers) and open sea areas. 2 Normative References
The following documents are essential for the use 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/T21845Test for water solubility of chemicals
GB/T 21851
GB/T21852
GB/T 21853
GB/T21855
GB/T22052
GB/T 22228
GB/T22229
Test for adsorption/desorption of chemicals by batch equilibrium methodPartition coefficient (n-octanol-water) of chemical by commercial liquid chromatographyTest chemical: Partition coefficient (n-octanol-water) by shake flask methodTest chemical: Hydrolysis test related to HDetermination of the relationship between vapor pressure and temperature of liquids and the initial decomposition temperature by using a wave vapor pressure gaugeMethod for determination of vapor pressure of industrial chemicals solids and liquids in the range of 10-1Pa to 10-5PaStatic methodDetermination of vapor pressure of industrial chemicals solids and liquids in the range of 10-3 Determination of vapor pressure in the range of Pa to 1 Pa OECD Guidelines for Testing of Chemicals No. 104 Vapor Pressure (Vapuur Presgure) OECD Guidelines for Testing of Chemicals No. 112 Dissociation Constants in Water 3 Terms and Definitions
The following terms and definitions apply to this document. 3.1
Test substance
Any substance, including the parent substance or relevant transformation products. 3.2
Transformation products
Transformation products
All substances formed by the biotic and abiotic transformation of the test substance, including CO and products in bound residues. 3.3
Bound resildues
Compounds that remain in the form of the parent substance or metabolites in soil, plants and animals after extraction. Extraction method 1
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GB/T 27853—2011
Cannot change the structure of the compound in essence. The nature of the binding can be determined to a certain extent by changing the extraction method and analytical technique. For example, covalent bonds, ionic bonds, adsorption binding and inductive effects can be identified by this method. The formation of binding residues will significantly reduce the bioavailability and bioavailability. 3.4
Aerobic transformation (oxidizing) Reaction that occurs in the presence of molecular oxygen [=1.3.5
anaerobicetransformation (reducing) Anaerobic transformation (reducing)
A reaction that occurs in the absence of molecular oxygen [3]. 3.6
Natural waters
Surface water obtained from ponds, rivers, streams. 3.7
Sediment
A mixture of minerals and organic matter that is deposited naturally by water and forms a boundary of a body of water, the latter containing high molecular weight compounds and high carbon and nitrogen contents.
Mineralisation
The complete degradation of an organic compound to CO under aerobic conditions. and H2O2 are converted to CH3, CO and H2O2 under anaerobic conditions.
Note that under the test conditions of this standard, when using radiolabeled compounds, the degradation is the ultimate degradation of the molecule, in which the labeled carbon atom is oxidized or reduced in a fixed manner, releasing a considerable amount of (O2, or CH3O2). 3.9
Half-life, fa.5
The time taken for the test substance to be converted by 50% when the conversion can be described by the law of first-order reaction kinetics. Note that the half-life of the test substance is independent of its initial concentration. 3.10
50% decay time disappearance time 50, DTso The time taken for the concentration of the test substance to decrease to 50% of the initial concentration. 3.11
Disappearance time 75, DT
75% decay time
The time taken for the initial concentration of the test substance to decrease by 75%. 3. 12
90% decay time
disappearancetime90,DTgo
The time taken for the initial concentration of the test substance to decrease by 90%, Test substance information
4.1 Test substance information includes:
a) Solubility in water (GB/T21845) L1; b) Solubility in organic solvents:
Vapor pressure (GB/T 22052, GB/T 22228GB/T 22229 and OECD No. 104) and Henry number; d) n-octanol-water partition coefficient (GB/T 21853 and GB/T21852)-called); 2
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Adsorption coefficient (KK or KGB/T21851) [
E) Hydrolysis (GB/T21855) L1);
Dissociation constant (pK, OECD112) Ci;
h) Chemical structure and isotopic labeling position (applicable to labeled compounds). Note: Official statement of the temperature corresponding to the determination of the above parameters. 4.2 Other information includes:
GB/T27853—2011
a) Toxicity data of the test substance to microorganisms, rapid and/or inherent biodegradability data, and aerobic and anaerobic transformation data in soil,
b) Qualitative and quantitative analysis methods of the test substance and its transformation products in water and sediments (including extraction and purification methods, see 9.2). 5 Experimental Principle
Under controlled laboratory conditions (constant temperature, avoid light), add a certain amount of test substance to the aerobic and anaerobic water-sediment test systems (see Appendix A for details), and after a certain period of incubation, determine the concentration of the test substance and the main transformation products in water and sediments through qualitative and quantitative analysis of the transformation products in the water phase and sediment phase, and detect the transformation rate of the test substance in the water-sediment system and in the sediment; detect the mineralization rate of the test substance and/or the test substance transformation products and the distribution between the two phases during constant temperature dark incubation (avoiding interference such as algal blooms), and determine the tn.S, DTu, DT and ITgo values. Within the data recognition range, t and.s, DT sp, DTrs and DT values can be determined, but they cannot be extrapolated beyond the experimental period. 6 Reference substances
When using spectral and chromatographic methods to qualitatively and quantitatively analyze transformation products, it is advisable to use reference substances. 7 Test Method Overview
7.1 Instruments and Reagents
The following equipment and reagents may be required in the test: The test generally uses glass containers (such as bottles, centrifuge tubes), but if the information of the test substance (such as the n-octanol-water partition coefficient, adsorption data a
, etc.) indicates that the test substance may adhere to the glass wall, it should be replaced with containers made of other materials (such as Teflon). b)
The typical gas flow culture test volume is shown in Figure B.1 in Appendix B; the static closed biometer culture bottle device is shown in Figure C.1 in Appendix C. The gas supply device should be able to switch between air and nitrogen; the gas outlet should have a closed container for collecting volatile products [11.33].
The specifications of the instrument should meet the requirements of the test in 8.1.1. The number of culture containers is determined according to the number of sampling times. Chemical analysis instruments, total organic carbon analyzer (TOC), gas chromatograph (GC), high performance liquid chromatograph (HPLC), thin layer chromatograph (TLC), mass spectrometer (MS), gas chromatograph-mass spectrometer (GC-MS), high performance liquid chromatograph-mass spectrometer (HPLC-MS) and nuclear magnetic resonance (NMR) instruments and equipment for chemical analysis of test substances and transformation products, as well as test systems for detecting radioactive isotope tracer labels, non-labeled test substances and anti-isotope dilution methods. e) Liquid scintillation analyzer and oxidation combustion analyzer, equipment for measuring water dissolved oxygen, redox potential, conductivity, particle size distribution, hardness, salinity, NO,/PO, "ratio and various values"; equipment for measuring sediment cation exchange, carbonate, water holding capacity, total ammonia and total phosphorus; equipment for analyzing nitrate, sulfate, bioavailable iron and other electron acceptors in sediment and water (see Table 1). g) Bottom sediment sampling equipment and standard laboratory equipment and instruments for physical and chemical analysis and biological detection. h) NaOH or KOH, H, SO, ethylene glycol, ethanolamine, xylene, paraffin, molecular sieve and other suitable reagents. 3
GB/T27853—2011
7.2 Selection of water and sediment
7.2.1 Selection of sediment for aerobic test
Usually, two kinds of sediments with obvious differences in organic carbon content and texture are used for aerobic test. One is sediment A with higher organic carbon content (2.5%~7.5%) and fine texture. A has a "fine texture" of clay plus silt (i.e. inorganic fragments with a particle size of less than 50 μm in the sediment) content greater than 50%. The other is a sediment with lower organic carbon (0.5%2.5%). The "coarse texture" of BB is "clay plus silt" content less than 50%. The difference in organic carbon content between A and B should be at least 2%. The difference in the content of "clay plus silt" should be at least 20%. If the test substance is likely to enter seawater, at least one type of water and sediment from the ocean is required. When selecting sediments, other parameters such as pH value should also be considered. 7.2.2 Selection of water and sediment for anaerobic test In strict anaerobic test, two kinds of sediment (including their corresponding water phase) should be collected from the anaerobic zone of surface water body, and both sediment and water phase should be stored, processed and transported under anaerobic conditions. Other parameters with important influence, such as pH value, should be considered according to the properties of the test object and other actual conditions. 7.3 Collection, processing and preservation of water and sediment 7.3.1 Collection site
The collection site should be selected according to the purpose and environment of the test. When selecting the collection site, small watersheds and upstream waters should be considered. Possible history of agricultural, industrial or domestic sewage discharge. Care should be taken to distinguish sediments from sludge contaminated by domestic sewage. Sediments contaminated by the test substance or substances with similar structures within four years before collection shall not be used for testing. 7.3.2 Sediment samples should be collected from the upper 5cm to 10cm of the sediment. The corresponding water samples should be collected at the same time and at the same location [a.20]: During anaerobic studies, sediments and their corresponding water samples should be collected and transported under anaerobic conditions-]. 7.3.3 Treatment of water and sediments
Sediment should be processed through Separate the sediment from the water by filtering, i.e., through a sieve with a pore size of 2 mm, using excess collected water to separate by wet sieving, and then discard the water. Then mix the known amount of sediment and water in proportion (see 8.1.1) and put them into the culture container to prepare for the incubation (see 7.4).
When conducting anaerobic studies, all treatment steps should be carried out under anaerobic conditions -25-. 7.3.4 Preservation of water and sediment
Use freshly collected sediment and water samples as much as possible. If the test cannot be carried out immediately after collection, the sediment and water samples should be collected according to 7.3.3. After sieving, store together, soak in water (water layer depth 6cm～10cm), place in the dark, and store for up to 4 weeks (-8) at 4℃±2℃.
Samples for aerobic tests should be stored in an environment with air circulation (such as in a loose-mouth container), while samples for anaerobic tests should be stored under anaerobic conditions.
During transportation and storage, water and sediments must not freeze, and sediments must not dry out. 7.4 Sediment and water acclimatization
Sediment and water samples should be acclimatized for a period of time before adding the test substance for testing. Acclimatization means that each water/sediment sample is transferred to the test culture container for acclimatization under conditions completely opposite to the formal test (see 8.1): the acclimatization period is when the permanent phase and sediment phase are clearly separated, the system pH is 4
GB/T27853-2011
dissolved in water The time taken for oxygen concentration, sediment and water redox potential to reach stability. The differentiation period is usually 1 to 2 weeks and should not exceed 4 months. 7.5 Labeling of test substances
The chemical purity and/or radiochemical purity of the test substance should reach more than 95%. Radioactive meta-labeled tracer atoms or non-labeled test substances can be used to determine the conversion rate. If the transformation pathway is to be studied and the mass balance is established, labeled substances should be used for tracing. It is recommended to use C-labeled atoms as labels, and }\C, \N, \H, 3\P and other meta-labeled atoms can also be used for labeling. Try to label the tracer atom on the most stable part of the molecule. For example, if the test substance contains one ring, the tracer atom should be marked on this ring. If the test substance contains two or more rings, each ring should be marked separately and the whereabouts of each labeled ring should be studied and evaluated to obtain information on the formation of transformation products. 8 Test procedures
8. 1 Test conditions
8.1.1 Amount of water and sediment
The test is carried out in a culture container (see 7.1). The minimum amount of sediment in each container is 50g (hereinafter referred to as weight). The volume ratio of test water to sediment is between 3:1 and 1:1, and the sediment layer is 2.5cm±0.5cm. In order to achieve a constant concentration distribution of the test substance at each point in the container, the amount of water and sediment is adjusted on the basis of maintaining the correlation between the depth of the water column in the test container and the depth of the field water (generally assumed to be 100cm, but other depths can also be used). For calculation examples, see Appendix D. 8, 1. 2 Test temperature
The test temperature range is between 10℃ and 30℃, and the suitable temperature is 20℃±2℃. According to the information of the test substance and the actual needs, the test can be carried out at a lower temperature (such as 10C). 8.2 Treatment and addition of test substances
8.2.1 Determination of test substance concentration
The test substance concentration should be determined by the predicted environmental emissions, and ensure that it is sufficient to detect the transformation process of the test substance and identify the morphology and degradation of the transformation products. Ensure that the test concentration of the test substance does not affect the viability of microorganisms in the water-sediment system: The maximum dose indicated on the label of the plant protection chemical should be used as its maximum application rate, and the additive is calculated based on the surface area of the water layer of the test container:
Generally, the test substance can be tested with one concentration. If the test substance still has sufficient analytical accuracy at a lower concentration, and enters the surface water body through different pathways, resulting in obvious differences in concentration in the water body, the second concentration can be selected for testing. When the test substance concentration is close to the detection limit at the beginning of the test and/or reaches 10% of the test substance application rate and the main transformation product is not easy to detect, a higher dose can be used as the test concentration (such as 10 times the dosage). 8.2.2 Addition of test substances
The test substance should be added to the water phase of the test system in the form of pure aqueous solution. The test substance water solution can be prepared and pre-mixed using a vibrator to ensure uniformity. Avoid using cosolvents (such as acetone and ethanol) as much as possible. If it is necessary to use it, its amount should not exceed 1% (volume ratio) of the liquid volume, and it should not have an adverse effect on the microbial activity in the test system. After adding the test substance water solution to the test system, gently stir the water phase and do not disturb the sediment phase as much as possible. It is not advisable to use the preparation of the test substance, because other components of the preparation may affect the dispersion of the test substance and/or the transformation products in the water phase and sediment phase. However, when the test substance has low water-penetration, the preparation of the test substance can be used as a substitute. 5Www.bzxZ.net
GB/T27853—2011
8.3 Control group
A control group should be set up in each water-sediment system. The test substance should not be added to the control group. The control group can be used to determine the amount of sedimentary microorganisms and the organic carbon content in the water and sediment phases at the end of the test. Two groups of controls (i.e., one group of controls for each water-sediment system) are used to detect the required parameters in the sediment and water at different stages (see Table 1). If a co-solvent is used to dissolve the test substance, two co-solvent control groups should be added to determine the effect of the co-solvent on the activity of the microorganism.
B.4 Culture
Prepare the test substance solution according to 8.2 and add it to the test system respectively, and culture it in a light-proof and constant temperature environment. Gas exchange is performed by gentle bubbling or by passing air or nitrogen containing CO2 through the water surface, while avoiding agitation of the sediment as much as possible. When surface aeration is used, gentle stirring of the upper layer of the water body is more conducive to the dispersion of gases in the water. Mildly volatile chemicals should be tested in biometer culture bottles with gentle stirring on the water surface, or in closed containers with a top layer filled with air or nitrogen and built-in vials for collecting volatile products. In aerobic tests, the headspace gas should be exchanged regularly to replenish the oxygen consumed by biological metabolism.
Carbon dioxide can be absorbed by 110 1/L potassium hydroxide or sodium hydroxide baths, and the volatile conversion products can be collected. These alkaline collection solutions should be replaced in time to prevent their absorption capacity from being reduced by absorption of carbon dioxide from the circulating air and carbon dioxide produced by respiration in aerobic tests. Volatile organic compounds are collected with ethylene glycol, xylene containing ethanolamine or 2% paraffin. Gases such as methane generated under anaerobic conditions can be collected with molecular sieves. These gases can be burned in a quartz tube filled with CuO at 900 °C to generate CO2, which can be absorbed by alkaline absorbents. 8.5 Duration of test and sampling
8.5.1 Duration of test
The incubation time is usually not more than 100 s. The test should be continued until the degradation pathway and water-sediment distribution pattern are established, or 90% of the test substance is removed by transformation and/or volatilization. 8.5.2 Sampling
During the incubation period, samples should be collected at least 6 times (including the last time). In order to accurately estimate the appropriate test period and sampling plan, a preliminary test can be carried out appropriately (see 8.6). For water-soluble test substances, additional sampling points should be added at the beginning of the test in order to determine the distribution rate between the water phase and the sediment phase.
At the appropriate sampling time, remove the incubation container (including duplicate samples) for analysis. Sediment and overlying water layer are analyzed separately. When removing the surface layer, the sediment should not be disturbed. Appropriate analytical methods should be used for the extraction and identification of the test substance and the transformation products. For anaerobic tests, anaerobic conditions should be maintained during sampling and analysis to prevent rapid re-oxidation of the anaerobic transformation products. Pay attention to removing substances adsorbed in the culture container and on the connecting tube for collecting volatiles. 8.6 Optional Preliminary Tests
In order to accurately design the test cycle and sampling plan, preliminary tests can be appropriately carried out. The preliminary test adopts the same test conditions as the formal test. The relevant test conditions and results should be briefly described in the test report. 8.7 Measurement and Analysis
8.7.1 Determination of Water-Sediment Sample Characteristics The key parameters of water and sediments that should be measured and reported (including the basis for the measurement method), as well as the test stages for measuring these parameters, are summarized in Table 1.
Sampling location/source
Redox potential
Joint sampling location/source
Flooding layer
Particle size distribution
Microbial biomass"
Redox potential
Determination of characteristic number of water-sediment samples [7.1%-20]Test process stages"
Field sampling
Observation (color/color)
Post-sampling treatment
Beginning of oxidation
Beginning of test
GB/T278532011
Test period
End of test
At the time of field sampling and the start and end of the test,Determination of biochemical oxygen demand (BOD) in water: at the beginning and end of the test, the measurement of trace/macro substances such as Ce, Mg and Mn in the water: total N and total Mn in the biomass during field sampling and at the end of the test helps to better interpret and evaluate the rate and pathway of aerobic biotransformation. In aerobic tests, the microbial respiration rate method, box steam method or plate count method (such as bacteria, actinomycetes, fungi and total colony count) are used; in anaerobic tests, the methane production rate is measured to determine the microbial biomass. The items marked with "" in the table are the items that should be measured. In addition, some other parameters can be measured and reported according to actual conditions. For example, parameters related to seepage include: particle size, alkalinity, sintering density, conductivity, NO2/PO4 (ratio and respective values); parameters related to sediment include: cation exchange capacity, water holding capacity, carbonate, total nitrogen and total phosphorus; parameters for seawater systems include salinity. Analysis of nitrate, sulphate, available iron and other electron acceptors (such as those available) in the sediment water are all conducive to the evaluation of redox conditions, especially conditions related to mass-oxygen conversion. 8.7.2 Analysis of samples
At each sampling in the water phase and sediment phase, the concentration of the test substance and the conversion product should be determined and reported (expressed as liquid concentration and percentage of addition). For tests using tracer labels, if the conversion product detected exceeds When the effective activity used in the entire water-sediment system is 10%, the product should be identified. Transformation products whose concentrations continue to increase during the test should be identified according to actual circumstances, even if their concentrations do not exceed the established limits, and the reasons should be stated in the report. The results of the gas/volatile capture system at each time (e.g., other gases such as volatile organic compounds) should be reported, and the mineralization rate and the amount of unextractable bound residue in the sediment should be reported for each sampling point. 9 Quality Assurance and Quality Control
9.1 Recovery
Immediately after adding the test substance, at least two parallel samples of water and sediment should be taken for analysis to confirm the reproducibility of the analytical method and the experimental operation7
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of-·consistency. The recovery rate in the subsequent stage of the test (when tracer markers are used) is obtained by respective mass balance. The recovery rate of the labeled substance should reach 90%-~110%, and the recovery rate of the unlabeled substance should reach 70%~110%. 9.2 Reproducibility and sensitivity of the analytical method
The reproducibility of the quantitative analysis method of the test substance and transformation product (excluding the initial extraction rate) is verified by twice analyzing the same extraction sample of water or sediment (incubation time is long enough to form transformation products). The minimum detection limit (LOD) of the test substance and transformation product in water or sediment should be at least 0.01 mg of the test substance per dry gram of sediment or water, or less than 1% of the initial addition amount of the test substance in the test system. A clear quantitative detection limit should be given. (L()Q). 9.3 Precision of transformation data
If pseudo-first-order reaction kinetics are applicable, the precision of the transformation data can be obtained by normalizing the concentration of the test substance as a function of time, and t. confidence limits or DTsc values can be calculated based on this. DTrs and DT values can also be calculated. 10 Data and reporting
10.1 Data processing and calculations
The mass balance or recovery of added radioactivity (see 9.1) should be calculated at each sampling time point and the results should be reported as a percentage of the added radioactivity. At each sampling time, the distribution of radioactivity between water and sediment is reported as both concentration and percentage.
DTs values (and DTrs and LYI, if possible) of the test substance should be calculated together with confidence limits (see 9.3). Information on the decay rates of the test substance in water and sediment can be obtained by appropriate evaluation methods: these evaluation methods include pseudo-first-order reaction kinetics, empirical curve fitting techniques using graphical or numerical solutions, and more complex evaluation methods such as single-compartment and multi-compartment models []. Each of the above methods has advantages and disadvantages, and there are also considerable differences in complexity. The assumption of pseudo-first-order reaction kinetics may oversimplify the degradation and partitioning processes, but it can provide easily understood parameters (rate constants or 1.5). These parameters are of great value for modeling and estimation of environmental concentrations. Empirical methods or linear transformations can obtain better fit curves to the data, thereby better estimating to.; and DTs, and if the data are appropriate, DTrs and DT values can also be obtained. However, the use of such derived constants is limited. In risk assessment, compartmental models can generate many useful constant values. These constants can describe the degradation rate and partitioning of chemicals in different compartments, and can also be used to predict the formation of major transformation products and degradation rate constants. In any case, the selected method should be evaluated and the tester should demonstrate the goodness of fit of the graphical and/or statistical curves. 10.2 Result Report
The test report should include the following:
a) Test substance:
Common name, chemical name, CAS number, structural formula (if labeled with a radioactive marker, the location of the marker should be indicated) and related physicochemical properties;
-Purity (impurities):
Radiochemical purity and molar activity of the labeled chemical. b) Reference substance:
Chemical name and structure of the reference substance used to characterize and/or identify the transformation products. c) Test sediment and water:
-The location of the sampling point, and as much detailed information as possible on the pollution history; all information on collection, storage and acclimation
\The various characteristics of the water and sediment samples listed in Table 1. 8As well as more complex evaluation methods such as one-compartment and multi-compartment models []. Each of the above methods has advantages and disadvantages, and there are considerable differences in complexity. The assumption of pseudo-first-order reaction kinetics may oversimplify the degradation and distribution process, but it can provide easy-to-understand parameters (rate constants or 1.5). These parameters are of great value for modeling and estimation of environmental concentrations. Empirical methods or linear transformations can obtain a better fitting curve for the data, based on which to.; and DTs can be better estimated. If the data are appropriate, DTrs and DT values can also be obtained. However, the use of such derived constants is limited. In risk assessment, compartmental models can generate many useful constant values. These constants can describe the degradation rate and chemical distribution of different compartments, and can also be used to predict the formation of major transformation products and degradation rate constants. In any case, the selected method should be evaluated, and the experimenter should prove the goodness of fit of the graphical and/or statistical curves. 10.2 Result Report
The test report should include the following:
a) Test substance:
Common name, chemical name, CAS number, structural formula (if labeled with a radioactive marker, the location of the marker should be indicated) and related physicochemical properties;
-Purity (impurities):
Radiochemical purity and molar activity of the labeled chemical. b) Reference substance:
Chemical name and structure of the reference substance used to characterize and/or identify the transformation products. c) Test sediment and water:
-The location of the sampling point, and as much detailed information as possible on the pollution history; all information on collection, storage and acclimation
\The various characteristics of the water and sediment samples listed in Table 1. 8As well as more complex evaluation methods such as one-compartment and multi-compartment models []. Each of the above methods has advantages and disadvantages, and there are considerable differences in complexity. The assumption of pseudo-first-order reaction kinetics may oversimplify the degradation and distribution process, but it can provide easy-to-understand parameters (rate constants or 1.5). These parameters are of great value for modeling and estimation of environmental concentrations. Empirical methods or linear transformations can obtain a better fitting curve for the data, based on which to.; and DTs can be better estimated. If the data are appropriate, DTrs and DT values can also be obtained. However, the use of such derived constants is limited. In risk assessment, compartmental models can generate many useful constant values. These constants can describe the degradation rate and chemical distribution of different compartments, and can also be used to predict the formation of major transformation products and degradation rate constants. In any case, the selected method should be evaluated, and the experimenter should prove the goodness of fit of the graphical and/or statistical curves. 10.2 Result Report
The test report should include the following:
a) Test substance:
Common name, chemical name, CAS number, structural formula (if labeled with a radioactive marker, the location of the marker should be indicated) and related physicochemical properties;
-Purity (impurities):
Radiochemical purity and molar activity of the labeled chemical. b) Reference substance:
Chemical name and structure of the reference substance used to characterize and/or identify the transformation products. c) Test sediment and water:
-The location of the sampling point, and as much detailed information as possible on the pollution history; all information on collection, storage and acclimation
\The various characteristics of the water and sediment samples listed in Table 1. 8
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