1、BS ISO19730:2008ICS 13.080.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDSoil quality Extraction of traceelements from soilusing ammoniumnitrate solutionThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31
2、March2009 BSI 2009ISBN 978 0 580 54932 8Amendments/corrigenda issued since publicationDate CommentsBS ISO 19730:2008National forewordThis British Standard is the UK implementation of ISO 19730:2008.The UK participation in its preparation was entrusted to TechnicalCommittee EH/4, Soil quality.A list
3、of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obli
4、gations.BS ISO 19730:2008Reference numberISO 19730:2008(E)ISO 2008INTERNATIONAL STANDARD ISO19730First edition2008-12-01Soil quality Extraction of trace elements from soil using ammonium nitrate solution Qualit du sol Extraction des lments traces du sol laide dune solution de nitrate dammonium BS IS
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8、he address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 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 eit
9、her ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedBS ISO 19730:2008ISO 1
10、9730:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Principle1 4 Reagents.1 5 Apparatus.2 6 Procedure.2 6.1 Sample preparation .2 6.2 Determining water content .2 6.3 Extraction .3 6.4 Phase separation.3 6.5 Stabilization of extrac
11、t 3 6.6 Blank test3 7 Calculation .3 8 Expression of results4 9 Test report4 Annex A (informative) Information on method of determining selected elements and treatment of particular types of soil 5 Annex B (informative) Precision6 Annex C (informative) Notes on homogenization, initial sample mass an
12、d extraction.8 Bibliography9 BS ISO 19730:2008ISO 19730:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carri
13、ed out through ISO 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 ISO, also take part in the work. I
14、SO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. 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 Internati
15、onal Standards. 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. Attention is drawn to the possibility that some of the el
16、ements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 19730 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. BS ISO 19730:2008ISO 197
17、30:2008(E) ISO 2008 All rights reserved vIntroduction 0.1 General The displacement of trace elements in soil cannot be described solely in terms of their solubility in water, since solid and dissolved compounds interact with one another in a large number of processes. Processes that proceed in one d
18、irection (e.g. weathering, mineralization) are accompanied by equilibrium reactions between solid and dissolved forms (e.g. adsorption/desorption, precipitation/dissolution). Factors that determine whether substances dissolve include the pH value, the redox potential, the concentration of ions in a
19、soil solution and its complexing agent content, all of which result in the soil solution varying with location and time. To be able to compare increases in easily soluble trace element concentrations in soil by a standardized method, soil extraction with ammonium nitrate is used, which is applicable
20、 to all those compounds of elements in a soil that may contribute to the concentration of dissolved elements under the prevailing site conditions (water-soluble compounds, exchangeably bound ions, readily soluble metal complexes). Extraction with ammonium nitrate solution fulfils the criteria to be
21、satisfied by an extractant for routine analyses. a) It can be applied to a wide spectrum of soils and elements in a wide concentration range. b) Disposal of the spent ammonium nitrate solution is environmentally friendly. c) The determination of the elements in the solution has low susceptibility to
22、 interference. The concentrations of elements in extracts obtained with other unbuffered salt solutions (such as calcium chloride or sodium nitrate solution) often correlate well with those in ammonium nitrate extracts, but the absolute concentrations are different and, at some sites, there may be c
23、oncentrations deviating substantially from average values. In addition, critical concentrations may be in the region of the limit of determination in the case of some extraction methods. In conjunction with extraction methods for determining the reserves of elements in soil (e.g. extraction with aqu
24、a regia), the proportions by mass determined by extraction with ammonium nitrate solution can serve as a basis for site investigations and for making recommendations with regard to use and restoration of soil containing critical concentrations of elements. 0.2 Prediction of impact 0.2.1 General The
25、concentrations determined by extraction with ammonium nitrate solution only provide an indication of the effects of trace elements, since it is necessary also to consider numerous site factors and sometimes the amounts of elements present in the soil in order to predict impact. Thus, designations su
26、ch as “biologically available”, “available to plants” or “components capable of migration” are not appropriate. In soil that is sometimes poorly aerated (e.g. water-logged soil), variations in the redox potential need to be considered when assessing the potential of arsenic and manganese to migrate.
27、 BS ISO 19730:2008ISO 19730:2008(E) vi ISO 2008 All rights reserved0.2.2 Migration of elements Extraction with ammonium nitrate solution has been found to be a suitable method of assessing easily soluble trace element fractions of a soil, whose element concentrations should be determined from sample
28、s of undisturbed soil taken from adequately distant sites and at different times. Major factors governing the transport of elements via seepage water are: their chemical and physical properties; the thickness of the unsaturated zone; the distribution of easily soluble elements over the depth of the
29、soil; and the actual speed with which the seepage water travels. The easily soluble trace element fractions in soil vary with time and location. Increased variability can generally be expected with varying soil acidity (e.g. in soil covered by forest vegetation) or hydromorphic modification (e.g. in
30、 warp soil), and can also be expected where the amounts of elements in the soil vary (e.g. due to mineralization). This should be considered when designing a sampling programme. BS ISO 19730:2008INTERNATIONAL STANDARD ISO 19730:2008(E) ISO 2008 All rights reserved 1Soil quality Extraction of trace e
31、lements from soil using ammonium nitrate solution 1 Scope This International Standard specifies a method of extracting trace elements from soil using a 1 mol/l NH4NO3solution (see the Introduction). NOTE Information on determining selected elements and treatment of particular types of soil is given
32、in Annex A. 2 Normative references The following referenced documents are indispensable 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 3696:1987,
33、 Water for analytical laboratory use Specification and test methods ISO 11464:1994, Soil quality Pretreatment of samples for physico-chemical analyses ISO 11465, Soil quality Determination of dry matter and water content on a mass basis Gravimetric method 3 Principle The soil sample with particle si
34、ze 99 %, whose purity has been established in preliminary tests) in water and make the solution up to 1 l with water. As an alternative, ready-to-use 1 mol/l high purity ammonium nitrate solution may be used. 4.3 Nitric acid, wHNO3= 65 %, HNO3 1,4 g/ml. 4.4 Nitric acid, diluted, = 5 %. Dilute 50 ml
35、of nitric acid (4.3) up to 1 l with water. 5 Apparatus The following equipment shall be used. 5.1 Forced-circulation drying oven, capable of being maintained at a temperature of (30 2) C. 5.2 Pestle and mortar, made of porcelain or sintered corundum. 5.3 Screens, having an aperture size of 2 mm for
36、air-dried samples and of 5 mm to 8 mm for freshly collected samples, and which do not cause contamination by the elements to be determined. 5.4 Balance, of accuracy 0,01 g. 5.5 Conical test tubes with screw caps, of nominal capacity 50 ml, made of polypropylene (or high density polyethylene, polytet
37、rafluoroethylene, perfluoroalkoxyalkane, or tetrafluoroethylene/hexafluoropropylene copolymer). Before use, check cleanliness of tubes and caps. If cleaning is necessary, fill the test tubes with dilute nitric acid (4.4) and allow to stand for 24 h, then wash with water and dry. 5.6 End-over-end sha
38、ker, capable of (20 2) r/min, placed in a thermostatically controlled room (20 2) C. 5.7 In-line membrane filter, for connection with a disposable syringe. Connect an in-line membrane filter of pore size 0,45 m to a disposable syringe with Luer-lock joint. If necessary, clean the membrane filter and
39、 the syringe by rinsing with dilute nitric acid (4.4). If colloids are present in the filtrate, use a 0,2 m membrane filter. High density filter papers can be used if they are tested and proved to be free of the elements to be determined. 5.8 Disposable plastic syringe, of nominal volume 10 ml or 20
40、 ml, with Luer-lock joint. 5.9 Centrifuge, able to centrifuge the test tubes (5.5) at 1 000 g to 3 000 g. 6 Procedure 6.1 Sample preparation The soil sample should be pretreated in accordance with ISO 11464. Use the soil fraction with grain size 2 mm. Extract soil samples from organic horizons (havi
41、ng more than 30 % by mass of organic matter, such as bog soil or topsoil and samples from reductomorphic horizons horizons affected by backwater or ground water such as coastal marsh soil or gley soil) in the freshly collected state and homogenize as described in Annex C. 6.2 Determining water conte
42、nt Determine the water content in accordance with ISO 11465. BS ISO 19730:2008ISO 19730:2008(E) ISO 2008 All rights reserved 36.3 Extraction Extract the soil at (20 2) C with 1 mol/l NH4NO3solution, using a mass-to-volume ratio of 1:2,5. Using a pipette, add 25,0 ml of ammonium nitrate solution (4.2
43、) to (10,00 0,01) g of air-dried or freshly collected soil (6.1) into a 50 ml conical test tube with screw caps (5.5). Close the test tube with a screw cap, mount it to an end-over-end shaker (5.6) and extract the soil at (20 2) r/min for (120 5) min. See Annex C for instructions on extracting organ
44、ic or reductomorphic horizons. 6.4 Phase separation Place the closed test tubes into a centrifuge and separate the solid phase by centrifugation with about 1 000 g for 10 min. Rinse the membrane filter and the syringe with 1 ml of extract solution and discard the rinsing solution. Filter 10 ml of th
45、e supernatant solution directly from the sample test tube into a 10 ml syringe equipped with a 0,45 m disposable in-line membrane filter. Store the filtered ammonium nitrate extract in a clean conical test tube. 6.5 Stabilization of extract After filtration, stabilize the extract with nitric acid (4
46、.3) by adding about 1 % of its volume of nitric acid (e.g. 0,1 ml of nitric acid to 10 ml of extract). This can also be done in connection with a dilution step (especially necessary if ICP techniques are applied for analysis). Transfer a fixed volume of the filtrate (e.g. 10,0 ml) using a pipette in
47、to a 50 ml volumetric flask, add 0,5 ml nitric acid (4.3) and fill up to the mark with water. Dilutions can be made also by mass. 6.6 Blank test Subject at least one blank to the same extraction procedure. 7 Calculation After subtracting the blank concentration of an element from the concentration o
48、f the sample solution, calculate the extractable element fraction, wx, expressed in g/kg of dry matter, determined in accordance with ISO 11465. For air-dried soil samples, use Equation (1) and for wet, freshly collected samples use Equation (2) air-dried sample: ()2BHOx0100100VF wwm +=(1) wet, fres
49、h sample: 22HOxBdHO100wVwFm=+(2) with water content, in %:20dHOd100mmwm= (3) where wxis the ammonium nitrate extractable mass fraction of an element (x) in soil, in g/kg; Bis the blank-corrected concentration of the element in the analysis solution, in g/l; V is the volume of ammonium nitrate solution added to the soil sample, in litres (nominal 0,025 l); BS ISO 19730:2008ISO 19730:2008(E) 4 ISO 2008 All rights reservedF dilution factor, Vend/Vi: Viis the volume of the aliq
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