1、BRITISH STANDARD BS 7755-4.1.1: 1995 ISO 11266: 1994 Soil quality Part 4: Biological methods Section 4.1 Biodegradability Subsection 4.1.1 Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic conditionsBS7755-4.1.1:1995 This British Standard, having been prepa
2、red under the directionof the Health and Environment Sector Board, waspublished under the authorityof the Standards Boardand comes into effect on 15 February1995 BSI 03-2000 The following BSI references relate to the work on this standard: Committee reference EPC/48 Draft for comment 92/56840DC ISBN
3、 058023844X Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EPC/48, Soil quality, upon which the following bodies were represented: Association of Consulting Scientists Association of County Councils Association of Enviro
4、nmental Consultants Association of Public Analysts British Gas plc British Geological Survey British Society of Soil Science Chemical Industries Association Confederation of British Industry Department of Agriculture Northern Ireland Department of the Environment Department of the Environment (Drink
5、ing Water Inspectorate) Department of Trade and Industry Department of Trade and Industry (Laboratory of the Government Chemist) Institute of Groundsmanship Institute of Terrestrial Ecology Institution of Environmental Health Officers Institution of Water and Environmental Management Macaulay Land U
6、se Research Institute Ministry of Agriculture, Fisheries and Food Soil Survey and Land Research Centre Water Research Centre Water Services Association of England and Wales The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Agrochemi
7、cals Association Ltd. British Wood Preserving and Damp-proofing Association Landscape Institute Soap and Detergent Industry Association Society of Chemical Industry Society of Environmental Toxicology and Chemistry University of East London University of Southampton Amendments issued since publicati
8、on Amd. No. Date CommentsBS7755-4.1.1:1995 BSI 03-2000 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Principle 2 5 Materials 2 6 Collection, handling and storage of soil 3 7 Procedure 3 8 Expression
9、of results 4 9 Test report 4 Annex A (informative) Bibliography 5 List of references Inside back coverBS7755-4.1.1:1995 ii BSI 03-2000 National foreword This Section of BS7755 has been prepared under the direction of the Health and Environmental Sector Board. It is identical with ISO11266:1994 Soil
10、quality Guidance on laboratory testing for biodegradation of organic chemicals in soil under aerobic conditions, published by the International Organization for Standardization (ISO). ISO11266 was prepared by Subcommittee4, Biological methods, of Technical Committee ISO/TC190, Soil quality, with the
11、 active participation, and approval of the UK. BS 7755 is being published in a series of Parts subdivided into Sections and Subsections that will generally correspond to particular International Standards. Other Parts of BS7755 are, or will be as follows. Part 1: Terminology and classification; Part
12、 2: Sampling; Part 3: Chemical methods; Part 4: Biological methods; Part 5: Physical methods. Section 4.3 of BS7755-4 is one of a group of standards dealing with biological tests on soil. Other Sections in this Part are, or will be, as follows. Section 4.2: Effects of pollutants on soil fauna; Secti
13、on 4.3: Effects of pollutants on soil flora; Section 4.4: Effects of pollutants on soil microorganisms. Cross-references International Standard Corresponding British Standard ISO 9408:1991 BS EN 29408:1993 Water quality. Evaluation in an aqueous medium of the “ultimate” aerobic biodegradability of o
14、rganic compounds: method by determining the oxygen demand in a closed respirator (Identical) BS 7755 Soil quality Part 2 Sampling ISO 10381-6:1993 Section 2.6:1994 Guidance on the collection, handling and storage of soil for the assessment of aerobic microbial processes in soil (Identical) BS 7755 S
15、oil quality Part 3 Chemical methods ISO 10390:1994 Section 3.2:1995 Determination of pH (Identical) ISO 11260:1994 Section 3.3:1995 Determination of effective cation exchange capacity and base saturation level using barium chloride solution (Identical)BS7755-4.1.1:1995 BSI 03-2000 iii The Technical
16、Committee has reviewed the provisions of the drafts of ISO10694, ISO11261, ISO11274, ISO11277 and ISO11461 to which normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the nece
17、ssary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1
18、to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS7755-4.1.1:1995 BSI 03-2000 1 Introduction Organic chemicals may be introduced
19、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 considerably, depending not only on the molecular structure of the chemical, but also on soil conditions such as temperature, wa
20、ter 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 thereby the persistence of organic chemicals in
21、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 provides general guidelines for the selection and
22、 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. 1 Scope This International Standard provides guidance on t
23、he selection and conduct of appropriate test methods for the determination of biodegradation of organic chemicals in aerobic soils. It does not describe any specific test method. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provi
24、sions 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 investigate the possibility of applying the most recent editions of the standar
25、ds indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 9408:1991, Water quality Evaluation in an aqueous medium of the “ultimate” aerobic biodegradability of organic compounds Method by determining the oxygen demand in a closed respirometer. ISO
26、 10381-6:1993, Soil quality Sampling Guidance on the collection, handling and storage ofsoil for the assessment of aerobic microbial processes in the laboratory. ISO 10390:1994, Soil quality Determination ofpH. ISO 10694:, Soil quality Determination of organicand total carbon after dry combustion (“
27、Element analysis”) 1) . ISO 11260:1994, Soil quality Determination of cation exchange capacity and base saturation Method using barium chloride solution. ISO 11261:, Soil quality Determination of total nitrogen Kjeldahl method using titanium dioxide as catalyst 1) . ISO 11274:, Soil quality Determin
28、ation of the water retention characteristic Laboratory methods 1) . ISO 11277:, Soil quality Determination of particle size distribution 1) . ISO 11461:, Soil quality Determination of soil water content calculated on a volume basis Gravimetric method 1) . 3 Definitions For the purposes of this Inter
29、national Standard, thefollowing definitions apply. 3.1 biodegradation the molecular degradation of an organic substance resulting from the complex actions of living organisms 3.2 primary biodegradation the degradation of a substance to an extent sufficient to remove some characteristic property of t
30、he 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 breakdown of an organic compound to carbon dioxide, water, the oxides or mineral salts of any other elements present, and
31、 products associated with the normal metabolic processes of microorganisms 1) To be published.BS7755-4.1.1:1995 2 BSI 03-2000 3.4 persistence the residence time of a chemical species in a specifically defined compartment of the environment 3.5 the disappearance time DT-50 the time taken for the conc
32、entration of a given compound to decrease by50% of its original value 3.6 the disappearance time DT-90 the time taken for the concentration of a given compound to decrease by90% of its original value 3.7 bound residues; non-extractable residues chemical species in plants and soils, originating from,
33、 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 considered to exclude fragments recycled through metabolic pathways leading to natural products. (For examples and further inf
34、ormation, see 3 inAnnex A.) 3.8 mineralization the complete degradation of an organic substance to inorganic products 4 Principle After addition of the test compound to a selected soil(5.1), biodegradation is measured under aerobic conditions (see ISO9408). Use of a radiolabelled compound allows det
35、ermination of the rate of disappearance of the test compound and the formation of metabolites, carbon dioxide, other volatiles and non-extractable residue. The metabolites should be identified using appropriate analytical methods. The disappearance of the test compound can also be followed by specif
36、ic 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 not possible to obtain clean samples owing to contamination which has already been introduced, the soil selected should have compar
37、able properties. The field history of the soil used should be considered and recent amendments, such as tillage practices and pesticide applications, noted. Precise data should be provided on the sampling site, its location, the presence of plants or previous crops, the date of removal of the sample
38、 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. It is therefore recommended that at least the following tests are performed on the selected soil. a) Physical properties: 1) parti
39、cle size analysis in accordance with ISO11277; 2) field water content in accordance with ISO11461; 3) total water holding capacity and/or water retention characteristic in accordance with ISO11274. b) Chemical properties: 1) pH of the soil in accordance with ISO10390, or the pH in KCl solution or Ca
40、Cl 2solution; 2) organic matter content in accordance with ISO10694; 3) cation exchange capacity (CEC) in accordance with ISO11260; 4) nitrogen content in accordance with ISO11261. c) Biological properties: The microbial activity should be determined by either using an appropriate biodegradable refe
41、rence compound or by determining active biomass in accordance with an International Standard which will be published later. NOTE 1It may be useful to determine the microbial activity before conducting a biodegradation test, and to determine whether any changes in microbial activity have occurred dur
42、ing the test. 5.2 Test material Ideally, substances to be tested should be pure compounds (chemical purity98%). The influence of any carriers or formulation ingredients should also be considered. The following data on compounds are important for the interpretation of results: name (IUPAC); structure
43、; relative molecular mass; data on purity; stability in water and in organic solvents; solubility in water;BS7755-4.1.1:1995 BSI 03-2000 3 vapour pressure; octanol/water partition coefficient; sorption constant; acid dissociation constant; for radiolabelled chemicals: the nature and position of the
44、label, specific activity, radiochemical purity. NOTE 2The results of studies using radiolabelled materials depends on the position of the radiolabel. 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 stora
45、ge of soil It is important that ISO10381-6 is followed to ensure that viability of soil microorganisms is maximized during sampling. 7 Procedure 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
46、of ways: a) in water (depending on the solubility in water); b) in organic solvents (depending on the solubility in the solvent). The amount 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 b
47、e taken into account; c) directly as a solid, for example mixed in quartz sand. Care should be taken to avoid adding test material at toxic levels. Compounds which are toxic, or have inhibitory effects on soil microorganisms at the applied concentration, will interfere with the determination of biod
48、egradability. Also, if the substance is added in water, care should be taken to avoid over-wetting or compacting the soil. 7.2 Incubation The treated soil is divided into aliquots of at least50g (dry mass equivalent) and placed in incubation flasks. Generally at least two replicates per sampling poi
49、nt should be incubated. However, increasing the number of replicates increases the precision of the test. When using unlabelled test 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 incubation system to be used will depend on the method(s) of analysis and measurement. A number of systems are available and some of them ar
