BS ISO 14388-1-2014 Soil quality Acid-base accounting procedure for acid sulfate soils Introduction and definitions symbols and acronyms sampling and sample preparation《土质 酸式硫酸盐土壤的.pdf

1、BSI Standards PublicationBS ISO 14388-1:2014Soil quality Acid-baseaccounting procedure for acidsulfate soilsPart 1: Introduction and definitions, symbolsand acronyms, sampling and samplepreparationBS ISO 14388-1:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of

2、ISO 14388-1:2014.The UK participation in its preparation was entrusted to TechnicalCommittee EH/4, Soil quality.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Use

3、rs are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 78160 5ICS 13.080.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of t

4、heStandards Policy and Strategy Committee on 30 September 2014.Amendments issued since publicationDate Text affectedBS ISO 14388-1:2014 ISO 2014Soil quality Acid-base accounting procedure for acid sulfate soils Part 1: Introduction and definitions, symbols and acronyms, sampling and sample preparati

5、onQualit de leau Mthode de comptage acide-base pour les sols sulfats acides Partie 1: Introduction et dfinitions, symboles et acronymes, chantillonnage et prparation des chantillonsINTERNATIONAL STANDARDISO14388-1First edition2014-08-01Reference numberISO 14388-1:2014(E)BS ISO 14388-1:2014ISO 14388-

6、1:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All 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

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8、gPublished in SwitzerlandBS ISO 14388-1:2014ISO 14388-1:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Abbreviated terms 85 Principle 86 Apparatus . 87 Sampling and sample pre-treatment in the field 98 Sam

9、ple pre-treatment in the laboratory 108.1 General 108.2 Drying 108.3 Removal of 2 mm size material . 118.4 Final grinding of the laboratory sample. 118.5 Storage and archiving of samples 129 Calculation of extraneous material 1210 Pre-treatment report 1211 Calculation of the acid-producing potential

10、 of acid sulfate soil using an acid-base accounting method 1311.1 General 1311.2 Procedure . 1311.3 Calculation . 14Annex A (normative) Chromium suite and SPOCAS suite acid-base accounting .16Bibliography .18BS ISO 14388-1:2014ISO 14388-1:2014(E)ForewordISO (the International Organization for Standa

11、rdization) 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 established has the right t

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15、d during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on t

16、he meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/

17、TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics.ISO 14388 consists of the following parts, under the general title Soil quality Acid-base accounting procedure for acid sulfate soils: Part 1: Introduction and definitions, symbols and acronyms, sampling and sample pr

18、eparation Part 2: Chromium reducible sulfur (CRS) methodology Part 3: Suspension peroxide oxidation combined acidity and sulfur (SPOCAS) methodologyiv ISO 2014 All rights reservedBS ISO 14388-1:2014ISO 14388-1:2014(E)IntroductionAcid sulfate soils are a complex group of predominantly low-lying coast

19、al soils and sediments that contain iron sulfides and/or their oxidation products. Typically, the sulfide present is pyrite (FeS2); though in some instances, iron monosulfides can be important. Acid sulfate soils are most prevalent in tropical and sub-tropical regions, but also occur in temperate an

20、d sub-arctic regions. When maintained in reduced and waterlogged conditions, the pyrite and other sulfides in these soils will not oxidize; and when they are in this state, the soils are generically termed potential acid sulfate soils. When these soils are exposed by whatever mechanism of disturbanc

21、e to atmospheric and dissolved oxygen, the sulfides they contain oxidize to sulfate and ferric ions, producing acid at the same time. The complete oxidation of pyrite by oxygen is generally represented by Formula (1):FeS2 + 15/4O2 + 7/2H2O Fe(OH)3 + 4 H+ 2 SO42-(1)However, the oxidation of pyrite do

22、es not always go to completion in the short-term, with oxidation products other than ferric hydroxide and sulfuric acid often forming. The iron hydroxy-sulfate mineral jarosite KFe3(SO4)2(OH)6, can be a conspicuous product of the oxidation process in acid sulfate soil. These oxidation products, as w

23、ell as other metal ions from the soil (e. g. aluminium) that are dissolved by the acid can have deleterious environmental, agronomic, and economic impacts. Where the pH of these soils falls to 4 or below (as a consequence of sulfide oxidation), they are generically termed actual acid sulfate soils (

24、AASS). When potential acid sulfate soil contains carbonate or other minerals with an acid neutralizing capacity (ANC) (e. g. calcite in the form of finely divided shell material), they cannot become acidic when they oxidize.Because of the many possible complex chemical reactions, the characterizatio

25、n of acid sulfate soils using analytical methods can be a complex process, but accurate characterization is crucial to the management of these soils. Chemical analysis provides the data necessary to assess the acid-producing potential of these soils. From these data, acid-base accounting can be used

26、 to determine the dosing rate of alkaline ameliorants needed to fully treat any net acidity. Once dosed accordingly, these soils should not generate acidity, thereby minimizing potential adverse impacts on the environment and/or infrastructure.Conceptually, the best way to assess the acid-producing

27、potential of these soils is through an acid-base accounting (ABA) procedure, whereby the potential sulfidic acidity, existing acidity, and acid neutralizing capacity (ANC) are quantified. These components of the acid-base account can be determined separately by the various methods of test in this se

28、ries of ISO 14388. Once the individual components are determined, the net acidity can be calculated as:Net acidity = Potential sulfidic acidity + Existing acidity ANCA number of approaches exist for the determination of potential sulfidic acidity (i. e. the acidity that can be generated by the oxida

29、tion of sulfides). The sulfide content can be measured by either reduction methods (e. g. chromium reducible sulfur SCR) or oxidation methods (e. g. peroxide oxidizable sulfur SPOS). The sulfidic acidity generated by these soils can then be calculated from the sulfide content determined. Alternative

30、ly, the potential sulfidic acidity can be measured directly by titration, following accelerated oxidation of the sulfides with hydrogen peroxide, e. g. titratable sulfidic acidity (TSA).Existing acidity might be present in the soil as a result of previous oxidation of sulfides. If this acidity is in

31、 exchangeable and/or soluble forms, it is termed actual acidity. It is measured by titrating a 1 mol/l potassium chloride (KCl) soil suspension to pH 6,5 and is termed titratable actual acidity (TAA). Soil suspensions with pHKCl values 6,5 are deemed to have no actual acidity. Additional existing ac

32、idity can also reside in sparingly soluble iron and aluminium hydroxy-sulfate phases such as jarosite. This component of the existing acidity is termed retained acidity. It can be estimated by determining net acid-soluble sulfur (SNAS) or residual acid-soluble sulfur (SRAS); it is usually measured o

33、n soil with a pHKCl 6,5, it can contain some ANC (e. g. in the form of CaCO3from shell). The ANC can be determined by various methods e. g. inorganic carbon (CIN), using a combustion furnace, or acid digestion followed by titration of unreacted acid (ANCBT). ISO 2014 All rights reserved vBS ISO 1438

34、8-1:2014ISO 14388-1:2014(E)These individual components can be combined into analytical suites that streamline the process of acid-base accounting. Figure 1 shows the possible options to take for the analysis of acid sulfate soils. The two principal analytical suites, the chromium suite and the SPOCA

35、S suite are conceptualized in Figures 2 and 3 respectively.The chromium suite combines the measurement of SCRwith various measures of existing acidity and ANC using a decision-tree based on the value of pHKCl. In soils where pHKCl 6,5, and hence there is a chance of ANC being present, ANC can be est

36、imated by various methods such as (CIN) analysis and ANC by back titration (ANCBT). Where pHKCl2 mm) prior to sending the field sample to the laboratory. The presence of such fragments, their size, shape, and abundance (and whether they have been removed during sampling) should be recorded in field

37、sampling notes.For the chemical analysis to most closely reflect the condition of the acid sulfate soil in its natural state at the time of sampling, the handling, preparation and storage of these soils should be such that potential for oxidation of pyrite is minimized.8 Sample pre-treatment in the

38、laboratory8.1 GeneralSamples shall be processed so as to minimize any possible temporal changes in soil properties.Pre-treatment of soil should be carried out in a clean, dedicated preparation area. Care should be taken at all times to avoid contamination of the sample froma) the ambient atmosphere,

39、 andb) stored samples, or samples being processed nearby.8.2 Drying8.2.1 GeneralThe entire field sample shall be dried in accordance with either of the procedures specified in 8.2.2 and 8.2.3.WARNING Dried acid sulfate soils can be dusty and contain chemical contaminants, spores or pathogens and str

40、ongly acidic substances, and can pose health hazards.8.2.2 Oven-dryingSpread on a drying tray in as thin a layer as possible (and to a maximum thickness of 2 cm). Where possible, cloddy or plastic clay samples should be broken into lumps no more than 1 cm to 2 cm in diameter. If an estimate of field

41、 moisture is required, then retain a representative portion of the soil in a sealed polyethylene bag or moisture container. An as received moisture content determination can then be made.Dry in an oven (6.2) at a temperature of 85 C 5 C for 48 h, or after an initial drying period of 12 h until the w

42、eight loss from a sample, over a 6 h interval is less than 1 % of the final weight.NOTE 1 Samples are rapidly dried in a fan-forced air-extracting oven at 85 C 5 C to kill bacteria and to minimize further pyrite oxidation.NOTE 2 Typically, pH decreases of 0,25 to 1 units have been recorded on oven-d

43、rying, without any measurable oxidation of sulfides, although larger pH decreases on oven-drying large samples and some oxidation equating to 2 % of average TPA have been described.110 ISO 2014 All rights reservedBS ISO 14388-1:2014ISO 14388-1:2014(E)NOTE 3 It was demonstrated that oxidation of betw

44、een 3 % and 5 % of the reduced inorganic sulfur (as measured by SCR) occurred in a wide variety of materials even when dried quickly in a fan-forced oven, and that this was accompanied by large increases in water-soluble sulfate.28.2.3 Freeze-dryingAs an alternative to oven-drying, freeze-drying can

45、 be used to minimize sample oxidation (e. g. ISO 167204). Freeze-dry soil sample according to the manufacturers instruction manual for your specific freeze-dryer.NOTE While freeze-drying soil samples can cause minor changes in S constituent analysis when compared to fresh, field-moist, refrigerated

46、samples, greater change is caused by oven-drying.38.3 Removal of 2 mm size material8.3.1 Preliminary separationAfter drying the field sample; shells, stones, and any other particles greater than 2 mm shall be removed.Do not remove soil aggregates, roots, and partially decomposed organic remnants suc

47、h as small roots which can contain sulfides.Removed coarse materials (fraction A) shall be identified, recorded, and if necessary, retained; if these materials contain significant sources of existing or potential acidity (e. g. sulfides) or alkalinity (e. g. carbonate), this should be considered sep

48、arately. The remaining dried material ( 2 mm material, fraction C is weighed (m2).b) Avoid crushing any coarse shell material to less than 2 mm.c) If required, the material retained on the sieve (fraction D) shall be identified, noted, and then added to fraction A; and the combined material weighed

49、(m1).NOTE Fraction C can be passed through a grinding mill (6.4) to facilitate representative sub-sampling and/or to enhance the fine grinding operation. This ground sample is still called the laboratory sample.8.4 Final grinding of the laboratory sampleA representative sub-sample (at least 50 g) of the laboratory sample shall be ground to a powder ( 2 mm (fractions A and D), expressed in grams (g);m2is the mass of dried sample after removal of extraneous/coarse material (fraction C), express