ISO-11265-1994.pdf

4853903 Ob83479 T 9 T INTERNATIONAL STANDARD IS0 11265:1994 TECHNICAL CORRIGENDUM 1 Published 1996-1 0-1 5 INTERNATKINAL ORGANIZATION FOR STANDARDMTKN* MWYHAPOAHAR ONAHHJAUHR no CTAHAAPTH3ALIHH. ORGANISATION INTERNATIONALE DE NORMALISATION Soil quality - Determination of the specific electrical conductivity TECHNICAL CORRIGENDUM 1 Qualité du sol - Détermination de la conductivité électrique spécifique RECTIFICATIF TECHNIQUE I Technical Corrigendum 1 to International Standard IS0 1 1265:1994 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. Pages 2 and 3 Subclauses 7.2.1 and 7.2.2 Replace the existing text by the following: 7.2.1 Measure the conductance (G) of the pc.-issium chloride solutions (4.2 to manual of the instrument. 7.2.2 Calculate, for each potassium chloride solution, a cell constant according to 4) according to the instruction K K = S G where This material is reproduced from IS0 documents under International Organization for Standardization (ISO) Copyright License number IHSIICCII996. Not for resale. No part of these IS0 documents may be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyright law of the country of use, or with the prior written consent of IS0 (Case postale 56,1211 Geneva 20, Switzerland, Fax +41 22 734 10 79), IHS or the IS0 Licensor's members. . . , . K is the cell constant, in reciprocal metres; . K is the specific electrical conductivity of one of the potassium chloride solutions, in millisiemens per metre; G is the conductance of the same potassium chloride solution, in millisiemens. Use the average of the calculated values as the cell constant of the instrument. The calculated cell constant shall not differ by more than 5 YO from the value given by the manufacturer ICs 13.080 Ref. No. IS0 11265:1994/Cor.l:1996(E) Descriptors: soils, quality, tests, soil testing, determination. electrical properties, electrical conductivity. O IS01996 Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- 4853903 Ob83480 701 H IS0 11265:1994/Cor. 1:1996(E) Subclause 7.3 In the second line, replace the symbol xm by K , . 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 13265 94 4853903 0577229 404 I NTER NATI O NAL STANDARD IS0 11265 First edition 1994-1 0-01 Soil quality - Determination of the specific electrical conductivity Qualité du sol - Détermination de la conductivité électrique spécifique Reference number IS0 1 1265:1994(E) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 11265 '44 = 48511703 0577230 126 IS0 11265:1994(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International 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 with 60, 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 International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 1 1265 was prepared by Technical Committee iSO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. Annex A of this International Standard is for information only. 0 IS0 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 CH-1 21 1 Genève 20 Switzerland Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 3L2b5 94 Y85I.1903 0577233 Ob2 = INTERNATIONAL STANDARD Q IS0 IS0 11265:1994(E) Soil quality - Determination of the specific electrical conductivity 1 Scope NOTE 1 For definitions of the concepts used, see IS0 7888. This International Standard specifies an instrumental method for the routine determination of the specific electrical conductivity in an aqueous extract of soil. Reagents The determination is carried out to obtain an indication of the content of water-soluble electrolytes in a soil. Use only reagents of recognized analytical grade. This International Standard is applicable to all types of air-dried soil samples. 4.1 Water, with a specific electrical conductivity not higher than 0,2 mS/m at 25 “C (grade 2 water ac- cording to IS0 3696). 4.2 Potassium chloride solution, 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, 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 re- cent editions of the standards indicated below. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. IS0 3696:1987, Water for analytical laboratory use - Specification and test methods. IS0 7888:1985, Water quality - Determination of electrical conductivity. c(KCI) = 0,l mol/l. Dissolve 7,456 g of potassium chloride, previously dried for 24 h at 220 “C $I 10 OC in water (4.11, and dilute to 1 O00 m l at 20 O C . The specific electrical conductivity of this solution is 1 290 mS/m at 25 “C. 4.3 Potassium chloride solution, c(KCI) = 0,020 O mol/l. Pour 200,O ml of the potassium chloride solution (4.2) into a 1 O00 ml volumetric flask and dilute to volume with water at 20 O C . The specific electrical conductivity of this solution i s 277 mS/m at 25 O C . 4.4 Potassium chloride solution, c(KCI) = 0,010 O mo IS0 1 1464: 1 994, Soil quality - Pretreatment of sam- ples for physico-chemical analyses. 3 Principle Pour 100,O ml of the potassium chloride solution (4.2) into a 1 O00 ml volumetric flask and dilute to volume with water at 20 “C. The specific electrical conductivity of this solution is 1 4 1 mS/m at 25 “C. Air-dried soil is extracted with water at 20 “C f 1 “C at an extraction ratio of 1:5 (rn/V), to dissolve the electrolytes. The specific electrical conductivity of the filtered extract is measured and the result is corrected to a temperature of 25 O C . All the potassium chloride solutions (4.2, 4.3 and above) used for calibration shall be stored in tightly sealed bottles which do not release sufficient alkali or alkali-earth cations to affect the electrical conduc- tivity of the solutions. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- - IS0 11265 94 W 4853903 0577232 T T î = IS0 11265:1994(E) NOTES 2 Plastics bottles may be suitable. 3 For bottles containing potassium chloride solutions, plastics seals are recommended as glass will weld to the bottle. 4 The use of commercially available conductivity standards is permitted. 5 Apparatus and glassware 5.1 Conductivity meter, fitted with a conductivity cell, equipped with an adjustable measuring range setting and (automatic) temperature correction and having an accuracy of 1 mS/m at 20 O C . Preferably, the conductivity meter should also be equipped with a cell-constant control. 5.2 Analytical balance, with an accuracy of at least 0,Ol g. 5.3 Thermometer, capable of measuring to the nearest 0 , l O C . 5.4 Shaking machine, with a horizontal movement sufficiently vigorous to produce and maintain a 1:5 soi1:water suspension, placed in a environment where the temperature adjusted is maintained at 20 “C I 1 O C . NOTE 5 Machines with a speed of about 180 cycles per minute and a stroke of about 5 cm have been found suit- able. 5.5 Filter paper, with low ash and high retentive properties. 5.6 Shaking bottle, of capacity 250 ml, made of borosilicate glass or polyethylene. 5.7 Usual laboratory glassware. 6 Laboratory sample Use the fraction of particles smaller than 2 mm of air-dried soil samples pretreated according to IS0 11464. 7 Procedure 7.1 Extraction Weigh 20,OO g of the laboratory sample nd transfer to a shaking bottle (5.6). Add 100 ml of water (4.1) at a temperature of 20 “C f 1 O C . Close the bottle and 0 IS0 place it in a horizontal position in the shaking machine (5.4). Shake for 30 min. Filter directly through a filter paper (5.5). Carry out a blank determination in the same way. The value of the blank shall not exceed 1 mS/m. If the value of the blank exceeds this, repeat the extraction. NOTES 6 The volume of filtrate should be just sufficient to per- form the measurements. 7 An extraction ratio of 1:5 (m/V) is chosen to ensure that an extract is obtainable from all soils including those with high organic matter contents. Using a smaller ratio, it is hardly possible to obtain an extract for some soils. 8 The extraction should be performed at the chosen tem- perature of 20 “C i - 1“C, because the solubility of the salts present depends on the temperature. After the filtration, the temperature of the extract is allowed to change. The measurement is performed with the temperature adjusted to 25 “C. Measurement of the blank is carried out to determine how much the water, glassware and filter paper used contribute to the electrical conductivity of the extracts. 9 The shaking action should be just sufficient to produce and maintain a suspension. More vigorous shaking may lead to excessive dispersion of clay, difficulty in filtration and consequent adverse effects on conductivity. 7.2 Checking of the cell constant 7.2.1 Measure the conductivity (x,) of the potass- ium chloride solutions (4.2 to 4.4) according to the in- struction manual of the instrument. 7.2.2 Calculate, for each potassium chloriäe sol- ution, a cell constant according to K = x + à where K xs is the cell constant, in reciprocal metres; is the specific electrical conductivity of one of the potassium chloride solutions, ¡ri millisiemens per metre; is the measured electrical conductivity of the same potassium chloride solution, iri millisiemens per metre. Use the average of the calculated values as the cell constant of the instrument. The calculated cell constant shall not differ by more than 5 % from the value given by the manufacturer. X, 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 11265 94 4853903 0577233 935 W 0 IS0 7.2.3 Adjust the cell constant on the conductivity meter. 7.3 Measurement of the electrical conductivity of the filtrates Measure the electrical conductivity of the filtrates (xm) according to the instructions provided by the manufacturer of the conductivity meter (5.1). Carry out the measurements with the temperature cor- rected to 25 O C . Note the results to one decimal place, expressed in millisiemens per metre. 8 Interferences 8.1 The measured values of the electrical conduc- tivity can be influenced by contamination of the elec- trodes. This type of interference is very difficult to recognize. Pollution of the electrodes may change the cell con- stant, and this can be perceived by measuring the conductivity of the potassium chloride solutions. 8.2 Air bubbles on the electrodes, for example formed during warming of the extracts, perturb the measurements. 8.3 Measurements of electrical conductivities less than 1 mS/m are influenced by carbon dioxide and ammonia from the atmosphere. In these cases, measurements shall be carried out in an adapted measuring cell. Such measurements are outside the scope of this International Standard. IS0 11265:1994(E) 9 Repeatability The repeatability of the electrical conductivity measurements in two separately prepared filtrates shall satisfy the requirements of table 1. Table 1 - Repeatability I I Electrical conductivity Accepted variation I mS/m at 25 OC O to 50 5 mS/m 20 mS/m 10 % 50 to 200 10 Test report The test report shall contain the following information: a) b) C) dì a reference to this International Standard; all information necessary for complete identifi- cation of the sample; the results of the determination in whole num- bers, expressed in millisiemens per metre; details of any operations not specified in this International Standard or regarded as optional, and any other factors which may have affected the results. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:39:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 LL2b5 94 m 4853903 0577234 871 i Repeatability limit (r = 2.8 x sr) 2,446 8,434 4,806 31,229 Reproducibility standard deviation (sR) 7,889 9,021 13,340 62,439 Reproducibility relative standard deviation (%) 22,583 7,705 9,350 9,525 Reproducibility limit (R = 2,8 x sR) 22,088 25,259 37,352 174,828 IS0 1 1265: 1994( E) 2,976 4,116 13,244 11,524 Annex A (informative) Results of an interlaboratory trial for the determination of the specific electrical conductivity of soils In 1991, an interlaboratory trial was organized by the Samples 1 and 4 mentioned in tableA.l were col- Wageninge