ISO INTERNATIONAL STANDARD 14388-3 Firstedition 2014-08-01 Soil quality Acid-base accounting procedure for acid sulfate soils Part 3: Suspension peroxide oxidation combined acidity and sulfur (SPOCAS) methodology Qualite du sol-Méthodede comptageacide-basepourlessols sulfatésacides- Partie 3:Methodepar oxydationauperoxydeen suspension combinee a I'acidité et aux sulfures (SPOCAS) Referencenumber IS014388-3:2014(E) LSO Copyright International Organization for Standardization @IS02014 cense from IHS Not for Resale IS014388-3:2014(E) COPYRIGHTPROTECTEDDOCUMENT @ISO2014 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56.CH-1211 Geneva 20 Tel. + 4122 749 0111 Fax +41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland @ IS0 2014 - All rights reserved No reproduction or networking permited without license from IHS Not for Resale IS014388-3:2014(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. 2 Normative references .... 3 Terms and definitions ..2 4 Principle ..2 4.1 Actual acidity and retained acidity ..2 4.2 Titratableperoxideacidity,excessacid neutralizingcapacityandpotential sulfidic acidity. ..2 5 Reagents ..2 6 Apparatus. ..5 7 Procedure for determination of pHkci and TAA ..6 7.1 Preparation of the suspension. .6 7.2 Measurement of pHkcl 67 7.3 Measurement of TAA. 8 Calculation of TAA ..8 9 Procedure for determination of sulfur (Skcl), calcium (Cakcl) and magnesium (Mgkci) extractablewith 1mol/lpotassium chloride .8 10 Calculation of Skc, Cakc and Mgkci 9 11 Procedure for determination of peroxide pH (pHox), titratable peroxide acidity (TPA) and excessacid neutralizingcapacity (ANCe) 9 11.1 Peroxide digestion of sample. .9 11.2 Measurement of pHox. .10 11.3 Carbonatemodification (HCltitration topH4) ..11 11.4 Decompositionofexcessperoxide ..11 11.5 Measurement of titratable peroxide acidity (TPA) ..12 12 Calculation of TPA and ANCe ..13 12.1 Notation ..13 12.2 TPA without carbonate modification .13 12.3 ANCe (or TPA) with carbonate modification 14 13 Procedure for determiningperoxide sulfur (Sp),calcium (Cap) and magnesium (Mgp)....14 14 Calculation of peroxide sulfur (Sp), calcium (Cap) and magnesium (Mgp) .15 15 Procedure for determining acid extractable sulfur in soil residue after peroxide oxidation (SRAS) .15 15.1 General .15 15.2 Rinsing of peroxide digested soil residue, extraction with 4 mol/1 hydrochloric acid and determinationofextractablesulfur 16 16 Calculation of SRAS .16 16.1Calculation of acidity attributed to SRAs (acid-base accounting) ..16 17 Calculation ofTSA ..17 18 Calculation of Spos,Caa and MgA ..17 19 Precision ..17 20 Test report .18 Bibliography .20 iii license from IHS Not for Resale