ASTM_D_4698_-_21.pdf

Designation:D469821Standard 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 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For a specific hazard statement,see 15.5.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.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Standards:2D1129 Terminology Relating to WaterD1192 Guide for Equipment for Sampling Water and Steamin Closed Conduits(Withdrawn 2003)3D1193 Specification for Reagent WaterD3976 Practice for Preparation of Sediment Samples forChemical Analysis3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 partial digestion,nthe dissolution of a sedimentmatrix such that quantitation will produce a measurement ofless than 95%of the constituent present in the sample.In suchcases,recovery is operationally defined by the digestionprocedure.3.2.2 total digestion,nthe dissolution of a sediment ma-trix such that quantitation will produce a measurement which ismore than 95%of the constituent present in the sample.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 applicability1This 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 Nov.1,2021.Published January 2022.Originallyapproved in 1987.Last previous edition approved in 2013 as D4698 92(2013).DOI:10.1520/D4698-21.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1of either method,prior to final selection;or if a less rigorousdigestion could be employed(1-4).4Even then,experiencewith a particular sample type or digestion test method,or both,may have to be the final arbiter in test method selection.4.2