ASTM_D_4698_-_92_2013.pdf

Designation:D469892(Reapproved 2013)Standard Practice forTotal Digestion of Sediment Samples for Chemical Analysisof Various Metals1This standard is issued under the fixed designation D4698;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers two procedures for the total diges-tion of sediments for subsequent determination of metals bysuch techniques as flame atomic absorption spectrophotometry,graphite-furnace atomic absorption spectrophotometry,atomicemission spectroscopy,etc.1.2 This practice is applicable in the subsequent determina-tion of volatile,semivolatile,and nonvolatile metals of sedi-ments.1.3 Actual metal quantitation can be accomplished by fol-lowing the various test methods outlined under other appropri-ate ASTM standards for the metal(s)of interest.Beforeselecting either of the digestion techniques outlined in thispractice,the user should consult the appropriate quantitationstandard(s)for any special analytical considerations,and Prac-tice D3976 for any special preparatory considerations.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For a specifichazard statement,see Note 7.1.5 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1192 Guide for Equipment for Sampling Water and Steamin Closed Conduits(Withdrawn 2003)3D1193 Specification for Reagent WaterD3976 Practice for Preparation of Sediment Samples forChemical Analysis3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 total digestionthe dissolution of a sediment matrixsuch that quantitation will produce a measurement which ismore than 95%of the constituent present in the sample.3.2.2 partial digestionthe dissolution of a sediment matrixsuch that quantitation will produce a measurement of less than95%of the constituent present in the sample.In such cases,recovery is operationally defined by the digestion procedure.4.Summary of Practice4.1 Many procedures are available for the total digestion ofsediments prior to metal analysis,but almost all the methodsfall into one of two main classes:fusion and subsequentdissolution of the bead,and wet digestion which directlydissolves the sample with mineral acids.Each of the classeshas advantages and disadvantages,as do the individual proce-dures which fall under them.The two procedures outlined inthis practice were selected because they are the least restricted,in terms of utility,for dealing with a wide variety of matrices.Before choosing a particular method,the user should consultthe pertinent literature to determine the utility and applicabilityof either method,prior to final selection;or if a less rigorousdigestion could be employed.4,5,6,7Even then,experience witha particular sample type or digestion test method,or both,mayhave to be the final arbiter in test method selection.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.07 on Sediments,Geomorphology,and Open-Channel Flow.Current edition approved Jan.1,2013.Published January 2013.Originallyapproved in 1987.Last previous edition approved in 2007 as D4698 92(2007).DOI:10.1520/D4698-92R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Johnson,W.,and Maxwell,J.,Rock and Mineral Analysis,2nd Edition,JohnWiley&Sons,New York,1981,p.489.5Pinta,M.,Modern Methods for Trace Element Analysis,Ann Arbor SciencePublishers,Ann Arbor,1982,pp.133264.6Dolezal,J.,Povondra,C.,and Sulcek,Z.,Decomposition Techniques inInorganic Analysis,Elsevier Publishing Co.,New York,1968,pp.11157.7Shapiro,L.,“Rapid Analysis of Silicate,Carbonate,and Phosphate Rocks,”Revised Edition,U.S.Geological Survey Bulletin,1401,1975,p.76.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 Field collected samples should be treated according tothe procedures outlined in Practice D3976.4.3 Dried samples are ground to finer than 100 mesh(150m)using an appropriate grinding device or system.4.4 Procedure A Fusion with lithium metaborate/tet