1、DEUTSCHE NORM Mav 1997 Soil quality Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic conditions (IS0 11 266 : 1994) DIN 1 266 ICs 13.080 Descriptors: Soil quality, biodegradability, organic chemicals, testing. Bodenbeschaffenheit - Anleitung fr Laboratoriu
2、msuntersuchungen zur biologischen Abbaubarkeit von organischen Chemikalien im Boden unter aeroben Bedingungen (IS0 11 266 : 1994) This standard incorporates International Standard IS0 11266 Soil quality - Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic co
3、nditions. A comma is used as the decimal marker. National foreword This standard has been prepared by ISO/TC 190. The responsible German body involved in its preparation was the Normenausschu Wasserwesen (Water Practice Standards Committee), Technical Committee Boden - Biologische Bodenuntersuchungs
4、- verfahren . Expert assistance and specialized laboratories will be required to perform the analyses specified in this standard. The DIN Standards corresponding to the International Standards referred to in clause 2 of the IS0 Standard are as follows: IS0 Standard DIN Standard IS0 9408 DIN IS0 9408
5、 IS0 10390 DIN IS0 10390 IS0 10694 DIN IS0 10694 IS0 11260 DIN IS0 11260 IS0 11261 DIN IS0 11261 IS0 11274 DIN IS0 11274*) IS0 11277 DIN IS0 11277*) IS0 11461 DIN IS0 11461*) IS0 10381 -6 DIN IS0 10381-6 National Annex NA Standards referred to (and not included in Normative references) DIN IS0 10381
6、 -6 Soil quality- Sampling - Part 6: Guidance on the collection, handling and storage of soil for the assessment of aerobic microbial processes in the laboratory (IS0 10381 -6 : 1993) DIN IS0 10390 Soil quality - Determination of pH (IS0 10390 : 1994) DIN IS0 11 260 Soil quality - Determination of e
7、ffective cation exchange capacity and base saturation level using barium chloride solution (IS0 11260 : 1994 + Corr 1 : 1996) DIN IS0 11261 Soil quality - Determination of total nitrogen - Modified Kjeldahl method (IS0 11 261 : 1995) *) At present at the stage. IS0 Standard comprises 6 pages. No par
8、i of this standard may be reproduced without the prior permission of Ref. No. DIN IS0 11266 : 1997-0 Y Deutsches Institut fr Normung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group 06 Sales No. 0406 05.99 Page 1 I
9、S011266: 1994 Soil quality Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic conditions Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing Inter
10、national Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison wit
11、h ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an
12、 International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 1 1266 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 4, Biological methods. Annexe A of this International Standard is for information only. Intr
13、oduction Organic chemicals may be introduced into the soil both intentionally and accidentally, after which they may, or may not, degrade biologically. For chemicals which do degrade, the rate of degradation can vary con- siderably, depending not only on the molecular structure of the chemical, but
14、also on soil conditions such as temperature, water and oxygen availability which influence microbial activity. The activity of micro- organisms often plays a major role in degradative processes. It is necessary to have laboratory tests available to estimate the rate and extent of biodegradation and
15、thereby the persistence of organic chemicals in soil. Numerous laboratory methods are available for the estimation of aerobic biodegradation, but these differ considerably according to the specific circumstances, for example, soil type, temperature and incubation times. This International Standard p
16、rovides general guidelines for the selection and conduct of tests for determining the biodegradation of organic chemicals in aerobic soils. At the time of writing, there is insufficient agreement on methodology for testing biodegradability in anaerobic soils for guidelines to be prepared. Page 2 IS0
17、11266: 1994 1 Scope This International Standard provides guidance on the selection and conduct of appropriate test methods for the determination of biodegradation of organic chemi- cals in aerobic soils. It does not describe any specific test method. 2 Normative references The following standards co
18、ntain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investi
19、gate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 9408:1991, Water quality - Evaluation in an aqueous medium of the “ultimate ” aerobic biodegra- dability of organic co
20、mpounds - Method by determining the oxygen demand in a closed respirometer. IS0 10381-6:1993, Soil quality - Sampling - Guid- ance on the collection, handling and storage of soil for the assessment of aerobic microbial processes in the labora tory. IS0 10390:1994, Soil quality - Determination of pH.
21、 IS0 10694:-”, Soil quality - Determination of organic and total carbon after dry combustion (“Element analysis I). IS0 1 1260:1994, Soil quality - Determination of cation exchange capacity and base saturation - Method using barium chloride solution. IS0 1 1261 :-I, Soil quality - Determination of t
22、otal nitrogen - kjeldahl method using titanium dioxide as catalyst. IS0 11 274:-11, Soil quality - Determination of the water retention characteristic - Laboratory methods. IS0 11277:-), Soil quality - Determination of particle size distribution. IS0 11461 :-l), Soil quality - Determination of soil
23、water content calculated on a volume basis - Gravimetric method. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 biodegradation: The molecular degradation of an organic substance resulting from the complex actions of living organisms. 3.2 primary b
24、iodegradation: The degradation of a substance to an extent sufficient to remove some characteristic property of the parent molecule. In practice, this will be determined by analysis as a loss of parent compound or some specific function of the parent compound. 3.3. ultimate biodegradation: The break
25、down of an organic compound to carbon dioxide, water, the oxides or mineral salts of any other elements present, and products associated with the normal metabolic processes of microorganisms. 3.4 persistence: The residence time of a chemical species in a specifically defined compartment of the envir
26、onment. 3.5 the disappearance time DT-50 The time taken for the concentration of a given compound to de- crease by 50 % of its original value. 1) To be published. Page 3 IS011266: 1994 3.6 the disappearance time DT-90: The time taken for the concentration of a given compound to de- crease by 90 % of
27、 its original value. 3.7 bound residues; non-extractable residues: Chemical species in plants and soils, originating from, for example, organic molecules that are not extracted by methods which do not significantly change the chemical nature of these residues. These non- extractable residues are con
28、sidered to exclude fragments recycled through metabolic pathways leading to natural products. (For examples and further information, see 31 in annex A.) 3.8 mineralization: The complete degradation of an organic substance to inorganic products. 4 Principle After addition of the test compound to a se
29、lected soil (5.1 1, biodegradation is measured under aerobic conditions (see IS0 9408). Use of a radiolabelled compound allows determination of the rate of dis- appearance of the test compound and the formation of metabolites, carbon dioxide, other volatiles and non-extractable residue. The metaboli
30、tes should be identified using appropriate analytical methods. The disappearance of the test compound can also be followed by specific analysis. 5 Materials 5.1 Soil If practicable, soils selected for testing should come directly from the site where chemical contact is anticipated. However, if it is
31、 not possible to obtain clean samples owing to contamination which has already been introduced, the soil selected should have comparable properties. The field history of the soil used should be considered and recent amendments, such as tillage practices and pesticide applications, noted. Precise dat
32、a should be provided on the sampling site, its location, the presence of plants or previous crops, the date of removal of the sample from the field, and the sampling depth. 5.1.1 Soil characteristics A knowledge of soil characteristics is essential for full interpretation of the results of the study
33、. It is therefore recommended that at least the following tests are performed on the selected soil. a) Physical properties: 1) particle size analysis in accordance with IS0 11277; 2) field water content in accordance with IS0 11461; 3) total water holding capacity and/or water retention characterist
34、ic in accordance with IS0 11274. b) Chemical properties: 1) pH of the soil in accordance with IS0 10390, or the pH in KCI solution or CaCI2 solution; 2) organic matter content in accordance with IS0 10694; 3) cation exchange capacity (CECI in accordance with IS0 11260; 4) nitrogen content in accorda
35、nce with IS0 11261. c) Biological properties: The microbial activity should be determined by either using an appropriate biodegradable refer- ence compound or by determining active biomass in accordance with an International Standard which will be published later. NOTE 1 It may be useful to determin
36、e the microbial activity before conducting a biodegradation test, and to determine whether any changes in microbial activity have occurred during the test. 5.2 Test material Ideally, substances to be tested should be pure compounds (chemical purity 98 %). The influence of any carriers or formulation
37、 ingredients should also be considered. The following data on compounds are important for the interpretation of results: - name (IUPAC); - structure; - relative molecular mass; - data on purity; - stability in water and in organic solvents; - solubility in water; - vapour pressure; - octanol/water p
38、artition coefficient; - sorption constant; - acid dissociation constant; - for radiolabelled chemicals: the nature and position of the label, specific activity, radiochemical purity. Page 4 IS0 11266: 1994 NOTE 2 The results of studies using radiolabelled ma- terials depends on the position of the r
39、adiolabel. The label should thus be positioned in such a way that the transformation process may be followed as far as possible. 6 Collection, handling and storage of soil It is important that IS0 10381-6 is followed to ensure that viability of soil microorganisms is maximized during sampling. 7 Pro
40、cedure 7.1 Addition of test substance The concentration to be used in the test depends on the experimental objectives. The test chemical may be added in a number of ways: a) in water (depending on the solubility in water); b) in organic solvents (depending on the solubility in the solvent), The amou
41、nt of solvent used should be kept to the minimum necessary for the application of the compound. The possible toxicity and biodegradability of the solvent should be taken into account; c) directly as a solid, for example mixed in quartz sand. Care should be taken to avoid adding test material at toxi
42、c levels. Compounds which are toxic, or have inhibitory effects on soil microorganisms at the applied concentration, will interfere with the determi- nation of biodegradability. Also, if the substance is added in water, care should be taken to avoid over- wetting or compacting the soil. 7.2 Incubati
43、on The treated soil is divided into aliquots of at least 50 g (dry mass equivalent) and placed in incubation flasks. Generally at least two replicates per sampling point should be incubated. However, increasing the number of replicates increases the precision of the test. When using unlabelled test
44、material, controls should be run simultaneously. The controls should contain soil plus the amount of water or solvent which was used for the application of the test material in the treated replicates. 7.2.1 Incubation system The irxubation system to be used will depend on the method(s1 of analysis a
45、nd measurement. A number of systems are available and some of them are listed in Il 1 and I21 in annex A. The incubation system used should ensure that sufficient oxygen is present to maintain aerobic conditions. If it is necessary to distinguish between biological and other degradation or dissipati
46、on processes, a sterile incubation should be performed. If the evaluation of carbon dioxide is used to follow the degradation process, care should be taken when using alkaline soils. These soils may absorb carbon dioxide, resulting in an underestimation of carbon dioxide production. If mineralizatio
47、n measurements are carried out with a non-radiolabelled compound, attention should be given to the mineralization rate of the control, and possible production of carbon dioxide from inorganic carbonates. NOTE 3 A number of systems are described in Ill and I21 in annex A. 7.2.2 Incubation conditions
48、7.2.2.1 Illumination The incubation is usually carried out in the dark to avoid algal growth on the soil surface. However, if the contribution of algae to biodegradation needs to be considered, appropriate lighting conditions should be selected. Under such conditions, the contribution to degradation
49、 by photolysis may be significant and should be taken into account. 7.2.2.2 Temperature The incubation temperature should be selected according to the specific goals of the study. In general, maximum microbial activity in soil is found between 25 “C and 35 “C. However, for soils from temperate zones, a temperature between 10 “C and 25 “C is adequate and more representative of natural conditions. The minimum and maximum tempera- tures to which the incubation system is exposed should be measured and recorded at regular intervals throughout the incubation and should not vary by more th
