1、BRITISH STANDARD BS 7755-3.1: 1994 ISO 11465:1993 Soil quality Part 3: Chemical methods Section 3.1 Determination of dry matter and water content on a mass basis by a gravimetric method UDC 631.422:631.432.2BS7755-3.1:1994 This British Standard, having been prepared under thedirection of the Environ
2、mentand Pollution Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15March 1994 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference EPC/48 Draft for comment 92/53940 DC ISBN 0 580 23002 3 Committe
3、es responsible for this British Standard The preparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/48, upon which the following bodies were represented: Association of Consulting Scientists Association of Cou
4、nty Councils Association of Environmental 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 De
5、partment of the Environment (Drinking 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 Enviro
6、nmental Management Macaulay Land Use 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 subcommit
7、tees and panels: British Ceramic Research Ltd. Institute of Occupational Medicine National Rivers Authority Royal Society of Chemistry Society of Chemical Industry Amendments issued since publication Amd. No. Date CommentsBS7755-3.1:1994 BSI 07-1999 i Contents Page Committees responsible Inside fron
8、t cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Principle 1 5 Apparatus 1 6 Laboratory sample 1 7 Procedure 1 8 Expression of results 2 9 Repeatability 2 10 Test report 2 Table 1 Repeatability of w dmand in air-dried soil 3 Table 2 Repeatability of w dmand in field-
9、moist soil 3 List of references Inside back cover wH 2 O () w H 2 O ()BS7755-3.1:1994 ii BSI 07-1999 National foreword This Section of BS7755 has been prepared under the direction of the Environment and Pollution Standards Policy Committee. It is identical with ISO11465:1993 Soil quality Determinati
10、on of dry matter and water content on a mass basis Gravimetric method, published by the International Organization for Standardization (ISO). ISO 11465 was prepared by Subcommittee3, Chemical methods, of Technical Committee ISO/TC190, Soil quality, with the active participation and approval of the U
11、K. BS7755 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 2: Sampling; Part 3: Chemical methods; Part
12、 4: Biological methods; Part 5: Physical methods. Textual errors. When adopting the text of the international standard, the textual errors listed below were discovered. They have been marked in the text and have been reported to ISO in a proposal to amend the text of the international standard. In 7
13、.1.1, paragraph 1, line 4 and paragraph 3, line 2, 1mg should be read as10mg. In 7.1.4 line 4, 1mg should be read as 10mg. Cross-references The Technical Committee has reviewed the provisions of the drafts of ISO 11461 and ISO 11464 to which normative reference is made in the text and has decided th
14、at they are acceptable for use in conjunction with this standard. A British Standard does not purport to include all the necessary 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
15、 from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to4, 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 amen
16、dment table on theinside front cover.ISO11465:1993(E) BSI 07-1999 1 1 Scope This International Standard specifies a method for the determination of the dry matter content and water content of soil samples on a mass basis. This method can be applied to all types of soil samples. Different procedures
17、are specified for air-dried soil samples, for example samples pretreated according to ISO 11464, and for field-moist soil samples. For the determination of soil water content on a volume basis, refer to ISO 11461. 2 Normative references The following standards contain provisions which, through refer
18、ence 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 investigate the possibility of applying the
19、most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 11461:, Soil quality Determination of soil water content on a volume basis Gravimetric method 1) . ISO 11464:, Soil quality Pretreatment of samples for phy
20、sico-chemical analyses 1) . 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 dry matter content on a mass basis w dm dry residue of soil, expressed as a percentage by mass, after drying according to this International Standard 3.2 water content on a
21、 dry mass basis, mass of water evaporating from the soil when dried to constant mass at 105 C, divided by the dry mass of the soil and multiplied by 100 3.3 constant mass mass reached when, during the drying process, the difference between two successive weighings of the cooled sample, with an inter
22、val of 4 h between them, does not exceed 0,1 % (m/m) of the last determined mass NOTE 1Usually 16h to 24h is sufficient for drying most soils to constant mass, but certain soil types and large samples will require longer. 4 Principle Soil samples are dried to constant mass at 105 C 5 C. The differen
23、ce in mass of an amount of soil before and after the drying procedure is used to calculate the dry matter and water contents on a mass basis. 5 Apparatus 5.1 Drying oven, thermostatically controlled with forced air ventilation and capable of maintaining a temperature of 105 C 5 C. 5.2 Desiccator, wi
24、th an active drying agent. 5.3 Analytical balance, accuracy 10mg. 5.4 Container (moisture box) with lid, of capacity25ml to 100ml for air-dried soil samples and at least 100ml for field-moist soil samples, and made of waterproof material that does not absorb moisture. 5.5 Spoon 6 Laboratory sample U
25、se air-dried soil samples, for example samples pretreated according to ISO 11464, or field-moist soil samples taken according to the appropriate International Standards. 7 Procedure WARNING With soil samples from contaminated soils, special measures must be taken. It is important to avoid any contac
26、t with the skin and special measures must be taken during the drying process to prevent contamination of the laboratory atmosphere and other samples (ventilation, removal of the air, etc.). The procedures mentioned in 7.1 and 7.2 must be performed as quickly as possible to minimize evaporation. 7.1
27、Procedure for air-dried soil samples 7.1.1 Dry a container with lid (5.4) at 105 C 5 C and then cool it, with the lid closed, in a desiccator(5.2) for at least 45 min. Determine the mass (m 0 ) of the closed container, with an accuracy of 1mg 2) . Using a spoon (5.5), transfer 10g to 15 g of air-dri
28、ed soil to this container. 1) To be published. wH 2O 2) See national foreword for details of textual error.ISO11465:1993(E) 2 BSI 07-1999 Determine the mass (m 1 ) of the closed container and soil, with an accuracy of 1 mg 3) . 7.1.2 Dry the container and soil in a drying oven(5.1) at 105 C until co
29、nstant mass is reached. Dry the lid at the same time. NOTE 2Care should be taken that the very light soil particles are not removed from the container by a draught or wind. NOTE 3Decomposition of organic matter can, in general, be neglected at this temperature. However, for soil samples with a high
30、organic matter content 10 % (m/m), for example peaty soils, the method of drying should be adapted. In this case, the sample should be dried to constant mass at 50 C. Use of a vacuum will speed up this operation. NOTE 4Some minerals similar to gypsum lose water of crystallization at a temperature of
31、 105 C. NOTE 5If volatile (organic) substances are present, this method will not give a reliable determination of the water content. 7.1.3 Cool the container, with the lid closed, in a desiccator for at least 45 min. 7.1.4 Remove the container from the desiccator and immediately determine the mass (
32、m 2 ) of the closed container containing the oven-dried soil, with an accuracy of 1mg 3) . 7.2 Procedure for field-moist soil samples 7.2.1 Place the soil on a clean surface that does not absorb moisture (e.g. a glass plate) and mix well. Remove stones, twigs, etc. with a diameter greater than 2mm.
33、NOTE 6When soil samples have to be analysed for organic micropollutants, these samples should undergo special pretreatment. During these procedures, stones, twigs, etc. are not in principle removed from the sample. Therefore, the dry matter content of those soil samples should be determined accordin
34、g to the procedure specified in this International Standard without removal of stones, twigs, etc. 7.2.2 Dry a container with lid (5.4) at 105 C 5 C and then cool it, with the lid closed, in a desiccator(5.2) for at least 45 min. Determine the mass (m 0 ) of the closed container with an accuracy of1
35、0 mg. Using a spoon (5.5), transfer 30g to 40g of soil to this container. Determine the mass (m 1 ) of closed container and soil, with an accuracy of 10mg. 7.2.3 Dry the container and soil in a drying oven(5.1) at105 C until constant mass is reached. Dry the lid at the same time. NOTE 7See notes 2 t
36、o 5 in 7.1.2. 7.2.4 Cool the container, with the lid closed, in a desiccator for at least 45min. 7.2.5 Remove the container from the desiccator and immediately determine the mass (m 2 ) of the closed container containing the oven-dried soil, with an accuracy of 10mg. 8 Expression of results The wate
37、r content is calculated on a basis of oven-dried soil. Calculate the dry matter content (w dm ) or water content on a dry mass basis (), expressed as percentages by mass, to an accuracy of 0,1 % (m/m), using the following formulas: where NOTE 8Recalculation of a weighed amount of air-dried or field-
38、moist soil (x) to oven-dried soil (y) can be carried out using the following formula: NOTE 9The water content, calculated on a basis of oven-dried soil, may be greater than 100 %. 9 Repeatability The repeatability of separate duplicate determinations shall satisfy the conditions given in Table 1 and
39、 Table 2. 10 Test report The test report shall contain the following information: a) a reference to this International Standard; b) a complete identification of the sample; c) the results of the determination in terms of the dry matter content (w dm ) or the water content on a basis of dry mass () w
40、ith an accuracy of0,1% (m/m); d) particular characteristics of the soil (e.g. the presence of gypsum and, if field-moist soil samples are used, the presence of gravel, twigs,etc.); e) any details not specified in this International Standard or which are optional, and any other factors which may have
41、 affected the results. 3) See national foreword for details of textual error. m 0 is the mass, in grams, of the empty container with lid; m 1 is the mass, in grams, of the container plus air-dried or field-moist soil; m 2 is the mass, in grams, of the container plus oven-dried soil. wH 2O wdm m 2 m0
42、 m 1 m0 - =100 wH 20 m 1 m 2 m 2 m0 - =100 yx 100 100wH 2o + () - = wH 2OISO11465:1993(E) BSI 07-1999 3 Table 1 Repeatability of w dmand in air-dried soil Table 2 Repeatability of w dmand in field-moist soil Dry matter content, w dm Water content, Acceptable difference % (m/m) % (m/m) greater than u
43、p to and including greater than up to and including 96 0 4,0 0,2 % (m/m) absolute 0 96 4,0 0,5 % of the mean value w dmand Acceptable difference % (m/m) greater then up to and including 0 30 1,5 % (m/m) absolute 30 5 % of the mean value wH 2O wH 2O wH 2O wH 2O4 blankBS7755-3.1:1994 BSI 07-1999 List
44、of references See national foreword.BS 7755-3.1: 1994 ISO 11465:1993 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level.
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