1、BRITISH STANDARD BS ISO 10390:2005 Soil quality Determination of pH ICS 13.080.10 BS ISO 10390:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 22 March 2005 BSI 22 March 2005 ISBN 0 580 45659 5 National foreword This British Standard rep
2、roduces verbatim ISO 10390:2005 and implements it as the UK national standard. It supersedes BS 7755-3.2:1995 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee EH/4, Soil quality, to Subcommittee EH/4/3, Chemical methods and soil characteristics, which
3、has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled
4、 “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance wi
5、th a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related interna
6、tional and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 7 and a back cover. The BSI copyright notice displayed in this document indicates when the doc
7、ument was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 10390:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 10390 Second edition 2005-02-15 Soil quality Determination of pH Qualit du sol Dtermination du pH BSISO10390:2005IS:09301 O5002(E) DPlcsid Fremia ih
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12、ehe.r ISO cirypothg fofice saCe tsopale 65 eneG 1121-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mail coirypthgiso.o gr Web www.iso.org Pulbisdehi n Switlrez dnaii ISO 5002 Allr ithgsr esedevrBSISO10390:2005IS:09301 O5002(E) I SO 5002 All irthgs ersedevr iiiForeword ISO (the Internation
13、al Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been e
14、stablished has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standard
15、ization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for vo
16、ting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all su
17、ch patent rights. ISO 10390 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. This second edition cancels and replaces the first edition (ISO 10390:1994), which has been technically revised. BSISO10390:2005blankINTENRATIONAL T
18、SANDADR IS:09301 O5002(E)I SO 5002 All irthgs ersedevr 1Soil quality Determination of pH 1 Scope This International Standard specifies an instrumental method for the routine determination of pH using a glass electrode in a 1:5 (volume fraction) suspension of soil in water (pH in H 2 O), in 1 mol/l p
19、otassium chloride solution (pH in KCl) or in 0,01 mol/l calcium chloride solution (pH in CaCl 2 ). This International Standard is applicable to all types of air-dried soil samples, for example pretreated in accordance with ISO 11464. 2 Normative references The following referenced documents are indi
20、spensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1770:1981, Solid-stem general purpose thermometers ISO 3696:1987, Water for analytical l
21、aboratory use Specification and test methods 3 Principle A suspension of soil is made up in five times its volume of one of the following: water; a solution of potassium chloride (KCl) in water, c = 1 mol/l; a solution of calcium chloride (CaCI 2 ) in water, c = 0,01 mol/l. The pH of the suspension
22、is measured using a pH-meter. NOTE To make the procedure generally applicable to all types of soil samples, a volume-to-volume shaking ratio is chosen because then all soils can be treated in the same way. If a mass-to-volume ratio were chosen, the weighed amount of test sample would have to be adap
23、ted for soils with a low density, to enable the preparation of the suspension. For the purpose of this International Standard, taking the required volume of test portion with a measuring spoon is sufficiently accurate. 4 Reagents Use only reagents of recognized analytical grade. 4.1 Water, with a sp
24、ecific conductivity not higher than 0,2 mS/m at 25 C and a pH greater than 5,6 (grade 2 water in accordance with ISO 3696:1987). BSISO10390:2005IS:09301 O5002(E) 2 I SO 5002 All irthgs ersedevr4.2 Potassium chloride solution, c(KCl) = 1 mol/l Dissolve 74,5 g of potassium chloride in water (4.1) and
25、dilute to 1 000 ml. 4.3 Calcium chloride solution, c(CaCl 2 ) = 0,01 mol/l Dissolve 1,47 g of calcium chloride dihydrate (CaCl 2 2H 2 O) in water (4.1) and dilute to 1 000 ml. 4.4 Buffer solutions, for calibration of the pH-meter Use at least two of the following buffer solutions for calibration. Bu
26、ffer solutions having a similar or equivalent pH that are commercially available may also be used. NOTE The buffer solutions 4.4.1, 4.4.2 and 4.4.3 are stable for one month when stored in polyethylene bottles. 4.4.1 Buffer solution, pH 4,00 at 20 C Dissolve 10,21 g of potassium hydrogen phthalate (C
27、 8 H 5 O 4 K) in water (4.1) and dilute to 1 000 ml. The potassium hydrogen phthalate shall be dried before use for 2 h at 115 C 5 C. 4.4.2 Buffer solution, pH 6,88 at 20 C Dissolve 3,39 g of potassium dihydrogen phosphate (KH 2 PO 4 ) and 3,53 g of disodium hydrogen phosphate (Na 2 HPO 4 ) in water
28、 (4.1) and dilute to 1 000 ml. The potassium dihydrogen phosphate shall be dried before use for 2 h at 115 C 5 C. 4.4.3 Buffer solution, pH 9,22 at 20 C Dissolve 3,80 g of disodium tetraborate decahydrate (Na 2 B 4 O 7 10H 2 O) in water (4.1) and dilute to 1 000 ml NOTE Disodium tetraborate decahydr
29、ate may lose water of crystallization when stored for a long time. 5 Apparatus 5.1 Shaking or mixing machine 5.2 pH-meter, with slope adjustment and temperature control 5.3 Glass electrode and reference electrode, or combined electrode of equivalent performance In the case of pH values greater than
30、10, an electrode specifically designed for that range should be used. NOTE In soil systems, the danger of deterioration of performance caused by breakage or contamination of the electrodes is increased. 5.4 Thermometer or temperature probe, capable of measuring to the nearest 1 C, complying with typ
31、e C according to ISO 1770:1981. 5.5 Sample bottle, of capacity at least 50 ml, made of borosilicate glass or polyethylene with a tightly fitting cap or stopper. 5.6 Spoon, of known capacity of at least 5,0 ml. BSISO10390:2005IS:09301 O5002(E) I SO 5002 All irthgs ersedevr 36 Laboratory sample Use th
32、e fraction of particles of air-dried soil samples, or soil samples dried at a temperature not higher than 40 C, which passes through a sieve with a 2 mm mesh size. For example, soil samples pretreated according to ISO 11464 can be used. NOTE Drying can influence the pH of the soil. In some soil samp
33、les, particularly those containing sulfides, drying can lower the pH substantially. 7 Procedure 7.1 Preparation of the suspension 7.1.1 Take a representative test portion of at least 5 ml from the laboratory sample using the spoon (5.6). 7.1.2 Place the test portion in the sample bottle (5.5) and ad
34、d five times its volume of water (4.1), potassium chloride solution (4.2) or calcium chloride solution (4.3). 7.1.3 Shake or mix the suspension for 60 min 10 min, using the mechanical shaker or mixer (5.1), and wait at least 1 h but not longer than 3 h. Ingress of air during standing after shaking s
35、hould be avoided. 7.2 Calibration of the pH-meter Adjust the pH-meter as indicated in the manufacturers manual. Calibrate the pH-meter as specified in the manufacturers manual, using the buffer solutions (4.4) at 20 C 2 C. NOTE Using electrodes that are in good condition, equilibrium is usually reac
36、hed within 30 s. 7.3 Measurement of the pH Measure the pH in the suspension at 20 C 2 C immediately after or whilst being stirred. The stirring should be at such a rate to achieve a reasonably homogeneous suspension of the soil particles, but entrainment of air should be avoided. Read the pH after s
37、tabilization of the value is reached. Note the recorded value to two decimal places. If a swinging-needle pH-meter is used, the second decimal place should be estimated. NOTE 1 The reading can be considered stable for example when the pH measured over a period of 5 s varies by not more than 0,02 pH
38、units. The time required for stabilization is usually 1 min or less, but can depend on a number of factors including the value of the pH (at high pH-values, it is more difficult to reach stabilization); the quality of the glass electrode (differences in manufacture between electrodes) and its age; t
39、he medium in which the pH is measured (stabilization is reached quicker in a KCl or CaCl 2medium than in water); the differences in pH between samples in a series; mechanical mixing before or while the measurement is performed may help to achieve stable readings in a shorter time. BSISO10390:2005IS:
40、09301 O5002(E) 4 I SO 5002 All irthgs ersedevrNOTE 2 In samples with a high content of organic material (peat soils, pot soils, etc.), the suspension effect can play a role. For calcareous soils, it is possible that carbon dioxide is absorbed by the suspension. Under these circumstances, it is diffi
41、cult to reach an equilibrium pH-value. 8 Repeatability The repeatability, expressed in terms of the difference between the pH measurements in two separately prepared suspensions, shall satisfy the requirements given in Table 1. A summary of the results of an interlaboratory trial for the determinati
42、on of the pH of soils is given in Annex A. Table 1 Acceptable repeatability of pH measurement pH range Acceptable difference pH u 7,00 0,15 7,00 8,00 0,40 9 Test report The test report shall include the following information: a) a reference to this International Standard; b) all information necessar
43、y for complete identification of the sample; c) the aqueous medium used to make the suspension; whether the pH in H 2 O, pH in KCl solution or pH in CaCl 2solution has been determined; d) the results of the determinations, to the nearest 0,1 pH-unit; e) any difficulties experienced in establishing e
44、quilibrium conditions; f) details of any operation not specified in this International Standard or regarded as optional, as well as any factor which may have affected the results. BSISO10390:2005IS:09301 O5002(E) I SO 5002 All irthgs ersedevr 5Annex A (informative) Results of an interlaboratory tria
45、l for the determination of the pH in soils An interlaboratory trial was organized in 2004 to test the procedures specified in this International Standard. For this interlaboratory trial, the determination of the pH of four soils was carried out by 35 laboratories. The summary of the results of the i
46、nterlaboratory trial is presented in Tables A.1 to A.3. Sample 1 (cultivated sandy soil) and sample 2 (clayey cultivated soil) came from the Czech Republic. Samples 3 and 4 (both loamy cultivated soils) came from France. The repeatability value, r, and the reproducibility value, R, listed in Tables
47、A.1 to A.3, were calculated according to ISO 5725-2. Table A.1 Results of the interlaboratory trial for the determination of the pH in H 2 O Sample No. 1 2 3 4 Number of laboratories retained after eliminating outliers 35 33 32 33 Number of outliers (laboratories) 0 2 3 2 Number of accepted results
48、70 66 64 66 Mean value 5,72 7,60 8,08 6,40 Repeatability value (r = 2,8 s r ) 0,080,12 0,10 0,10 Reproducibility value (R = 2,8 s R ) 0,790,45 0,42 0,36Table A.2 Results of the interlaboratory trial for the determination of the pH in KCI Sample No. 1 2 3 4 Number of laboratories retained after elimi
49、nating outliers 35 35 34 33 Number of outliers (laboratories) 0 0 1 2 Number of accepted results 70 70 68 66 Mean value 5,00 7,13 7,38 5,67 Repeatability value (r = 2,8 s r ) 0,090,08 0,08 0,14 Reproducibility value (R = 2,8 s R ) 0,470,37 0,36 0,25BSISO10390:2005IS:09301 O5002(E) 6 I SO 5002 All irthgs ersedevrTable A.3 Results of the interlaboratory trial for the determination of the pH in CaCl 2 Sample
