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ŃŃ\R3Ų' Letter\ŃŃ ° Ń # I&mage <=8’’’’’’’’’’C’’ HKKKK1 2#Mü’ << deUU…Level 1Level 2Level 3Level 4Level 5(n$––ņ ņ(Ś  Ś1Ś  Ś)ó óŻ ƒ!ŻŻ  ŻŌ_ŌŃX°ŃŌ_ŌŅh°ŅŃH°ŃńńńńŅĄ°ŅńńńńńńŅŠ°ŅńńŃ  ŃÖ€ ’’ÖŌ‡X²ĮXXXŌńńńńŃ€T…ŃńńńńńńŃ€(‚Ńńń€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€€Š X ŠĢߍ€)!%WGCz|2ź!°č `Ą90*€@ H@Eh9°ŗ°č  °h9°ŗßĢņ ņą@€ € øąŌ#†XMĆXXX²ĮĄ#ŌŌ‡&Xk/XXXMĆŌ€Ō‡&&Č&X&Xk/ŌUNITED€STATES€ENVIRONMENTAL€PROTECTION€AGENCYˆŠ (Š Šą@CC!øąó óWASHINGTON,€D.C.€20460Ō#†&Xk/X&&&Ča#ŌˆŠ Ą ŠŌ#†XMĆXX&Xk/A#ŌŌ‡&Xk/XXXMĆŌĢĢą0 Ą ąą0 Ą%Ą%ąą0p  % %ąą0Č p %p %ąą0 Č %Č %ąą0x % %ąŌ#†XMĆXX&Xk/J#ŌAugust€7,€1998Ō‡&Xk/XXXMĆŌŠŅzx%x% ŠŅ ŠŅą Ą ąą€c c /Ė%ąŌ‡&^É^X&Xk/ŌOFFICE€OF€€€€€€€€€€€€€€€€€€€€€€€€ˆŠ Ā j Šą€ķķ2Ė%ąSOLID€WASTE€AND€EMERGENCY€€€€€ˆĢą€c c 1Ė%ąRESPONSE€€€€€€€€€€€€€€€€€€€€€€€ˆ¹Ņ°hŅŅ° ŅŌ#†&Xk/X^&^Év#ŌŌ#†XMĆXX&Xk/ #ŌĢņņMEMORANDUMóóŠ ŗ b  ŠĢSUBJECT:ą ` ąClarification€Regarding€Use€of€SW„846€MethodsŠ šB  ŠĢFROM:ą ` ąElizabeth€Cotsworth,€Acting€Director€ņ ņš šsš š€ó óŌ‡'Xł* XXXMĆŌMatt€Hale€forŌ#†XMĆX X'Xł*W#ŌŠ z" Šą  ąą ` ąOffice€of€Solid€WasteĢĢTO:ą  ąą ` ąRCRA€Senior€Policy€AnalystsŠ r Šą  ąą ` ąRegions€I€„€XĢĢą  ąIt€recently€came€to€the€attention€of€EPA's€Office€of€Solid€Waste€that€additional€guidanceĻis€needed€regarding€certain€methods€in€Update€III€to€ņņTest€Methods€for€Evaluating€Solid€Waste,Š 2Ś ŠPhysical/Chemical€Methodsóó€(SW„846)€and€the€use€of€SW„846€methods€in€general,€in€order€toŠ "Ź Šassure€appropriate€use€by€the€laboratories€and€the€regulated€community.€€The€purpose€of€thisĻmemorandum€is€to€set€forth€the€guidance€as€a€clarification€to€SW„846€for€reference€andĻdistribution€to€the€States€and€to€other€interested€parties,€including€laboratories€and€the€regulatedĻcommunity.ĢĢą  ąSW„846€contains€the€analytical€and€test€methods€that€EPA€has€evaluated€and€found€to€beĻamong€those€acceptable€for€testing€under€subtitle€C€of€the€Resource€Conservation€and€RecoveryĻAct€(RCRA).€€€In€most€situations,€SW„846€functions€as€a€guidance€document€setting€forthĻacceptable,€although€not€required,€methods€to€be€implemented€by€the€user,€as€appropriate,€inĻresponding€to€RCRA„related€sampling€and€analysis€requirements.€€The€methods€are€intended€toĻbe€used€and€modified,€as€needed,€to€promote€unbiased,€sensitive,€precise,€comparable,€andĻspecific€analyses€and€test€results.€€In€addition,€with€the€exception€of€method„defined€parametersĻ(e.g.,€Method€1311,€the€Toxicity€Characteristic€Leaching€Procedure),€SW„846€methods€need€notĻbe€applied€in€a€prescriptive€manner.€€The€Agency€strongly€recommends€that€the€regulated€entityĻdevelop€a€project„specific€sampling€and€analysis€plan€in€conjunction€with€other€professionalsĻ(e.g.,€laboratories)€and€the€regulating€authority,€to€address€both€sample€collection€and€methodĻapplication€and€to€assure€the€generation€of€data€of€the€appropriate€quality.€€The€Disclaimer€andĻChapter€Two€of€SW„846€provide€additional€guidance€regarding€the€appropriate€use€of€SW„846Ļmethods,€and€Chapter€One€provides€guidance€regarding€the€development€of€a€project„specificĻsampling€and€analysis€plan.€Ģā āŠ Ņ+z)- ŠŃ(‚ŃŃąHŃŃŃŃ  ŃŃTRY$3Ų' Letter3Ų'3Ų' Letter’3Ų'TŃŃ°XŃŃ  ŃńńŃT…ŃŃŃŃ  ŃŃTRY$3Ų' Letter3Ų'3Ų' Letter’3Ų'TŃŃĄHŃŃ°XŃŃ  Ńńńą  ąSW„846€also€is€a€"living€document"€that€changes€over€time€as€new€information,€analyticalŠ ° Šā ātechnologies,€and€data€are€developed€and€made€available.€€Advances€in€analyticalĻinstrumentation€and€techniques€are€continually€reviewed€by€the€Agency€and€periodicallyĻincorporated€into€SW„846€to€support€changes€in€the€regulatory€program€and€to€improve€methodĻperformance.€€Update€III€represents€such€an€incorporation€into€SW„846.€€The€update€wasĻfinalized€on€June€13,€1997€(62€FR€32452),€and€included€37€revised€methods€and€61€newĻmethods.€€Besides€providing€new€technologies€and€improved€methods,€the€Agency€strove€as€partĻof€Update€III€to€address€some€long„standing€concerns€or€misconceptions€regarding€the€use€ofĻSW„846€and€its€methods.€€ĢĢą  ąSubsequent€to€finalizing€Update€III,€the€Office€of€Solid€Waste€received€additional€publicĻcomments€regarding€the€content€of€a€few€of€the€methods.€€The€Agency€reviewed€the€commentsĻand€determined€that€additional€guidance€regarding€the€subject€methods€would€be€beneficial€to€theĻregulated€community€and€regulating€authorities.€€The€Agency€notes€that€this€guidance€simplyĻclarifies€the€original€intent€of€the€methods€and€the€manual,€and€does€not€represent€significantĻchanges€to€the€Update€III€methods€as€promulgated€on€June€13,€1997.€€In€the€future,€the€AgencyĻplans€to€revise€the€affected€SW„846€methods€to€include€this€guidance.€€ĢĢą  ąAttachment€1€to€this€memorandum€contains€a€synopsis€of€the€clarifications€to€certainĻportions€of€the€following€SW„846,€Final€Update€III€methods:ĢĢÓ*°,X‚X4ø —X°œX*Óą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦ŻŻš"šą0 4 ąŻ  ŻMethod€3550B,€Ultrasonic€ExtractionŻƒ"‡¦ŻųŻŒŠ`°4(#4(# ŠŒŻ  Żą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦˜Żš"šą0 4 ąŻ  ŻMethod€5021,€Volatile€Organic€Compounds€in€Soils€and€Other€Solid€Matrices€UsingŠ P  ŠEquilibrium€Headspace€AnalysisŻƒ"‡¦˜³ŻŒŠ 4(#4(# ŠŒŻ  Żą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦ŖŻš"šą0 4 ąŻ  ŻMethod€5035,€Closed„System€Purge„and„Trap€and€Extraction€for€Volatile€Organics€inŠ 0€ ŠSoil€and€Waste€SamplesŻƒ"‡¦ŖÅŻŒŠ 4(#4(# ŠŒŻ  Żą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦¶Żš"šą0 4 ąŻ  ŻMethod€6010B,€Inductively€Coupled€Plasma„Atomic€Emission€SpectrometryŻƒ"‡¦¶ŃŻŒŠ`4(#4(# ŠŒŻ  Żą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦“Żš"šą0 4 ąŻ  ŻMethod€8000B,€Determinative€Chromatographic€SeparationsŻƒ"‡¦“®ŻŒŠP4(#4(# ŠŒŻ  Żą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦bŻš"šą0 4 ąŻ  ŻMethod€8082,€Polychlorinated€Biphenyls€(PCBs)€by€Gas€ChromatographyŻƒ"‡¦b}ŻŒŠš@4(#4(# ŠŒŻ  ŻĢÓ- °,X›X°,X‚X4ø —X-ÓThe€methods€are€discussed€in€numerical€order,€as€listed€above.€€Attachment€2€to€thisĻmemorandum€provides€a€more€detailed€discussion€of€the€issues€surrounding€the€clarifications.€ĻThe€detailed€discussions€in€Attachment€2€should€be€reviewed€to€fully€appreciate€the€context€onĻwhich€the€clarifications€are€based.€€All€copies€of€this€memorandum€should€be€distributed€withĻboth€attachmentsĢĢcc:ą  ąMichael€ShapiroŠ p&Ą!$ Šą  ąBarnes€JohnsonĢą  ąKey€Regional€RCRA€ContactsĢą  ąRCRA€Branch€ChiefsĢą  ąEnforcement€Division€DirectorsĢą0  ąLarry€Reńńeńńńńińńd,€SuperfundŠ (#(# Šą0  ąAnna€Virbick,€USTŠ (#(# Šą0  ąWalt€Kovalick,€TIOŠ (#(# Šą0  ąDavid€Friedman,€EMMCŠ (#(# Šą0  ąTony€Pagliaro,€ACILŌ_ŌŠ ą.0*-(#(# ŠŲŲŌ_ŌńńńńŃ HŃńńńńńńńńŃ°XŃńńńńŃĄHŃńńńńŌ_ŌÖ€ šÖŌ_ŌŌ_ŌŌ_ŌŌ_ŌŌ_ŌŌ_ŌŌ_ŌŌ_Ōą@©©$ģąņ ņAttachment€1ó óˆŠ ° ŠńńÖ€ÖńńńńÖ€ĖƒÖńńą@ii ģąņ ņSynopsis€of€the€Clarifications€to€Certain€Update€III€SW„846€Methodsó óˆŠ  š Šą@SS&ģąņ ņJuly€1998ó óˆŠ ą ŠĢĢą  ąThis€attachment€provides€a€synopsis€of€the€clarifications€to€six€methods€from€Update€IIIĻto€SW„846.€€The€methods€are€discussed€in€numerical€order€and€include€Methods€3550B,€5021,Ļ5035,€6010B,€8000B,€and€8082.€€The€synopsis€of€each€method€is€supported€by€a€detailedĻdiscussion€in€Attachment€2.€€The€reader€should€review€the€detailed€discussions€of€these€issues,€inĻorder€to€more€fully€understand€the€context€of€these€clarifications.ĢĢĢņ ņSynopsis€of€Clarifications€to€Method€3550B€„€Ultrasonic€Extractionó óŠ š@  ŠĢ1.ą0  ąThe€Agency€recommends€that€the€statements€in€Sections€1.5€and€1.7€of€Method€3550BŠ Š  Šregarding€extraction€efficiency€and€organophosphorus€pesticides€be€treated€as€ņņcautionsóó,Š Ą Šnot€outright€prohibitions€on€the€use€of€this€extraction€technique.€€The€discussions€of€the€Ļorganophosphorus€pesticides€issue€in€Method€3500B€and€8141A€should€be€treated€in€aĻsimilar€fashion.Š (#(# ŠĢ2.ą0  ąThe€Agency€recommends€that€analysts€demonstrate€the€performance€of€ņņanyóó€extractionŠ pĄ Štechnique€at€concentrations€near€those€found€in€field€samples.€€Such€demonstrations€mayĻbe€performed€using€existing€performance€measures€such€as€the€initial€demonstration€ofĻproficiency,€laboratory€control€samples,€and€matrix€spike€and€matrix€spike€duplicateĻpairs,€as€already€described€in€SW„846.Š (#(# ŠĢĢņ ņSynopsis€of€Clarifications€to€Method€5021€Ō‡XĪpXXXMĆŌ„ó ó€Volatile€Organic€Compounds€in€Soils€andŠ P ŠOther€Solid€Matrices€Using€Equilibrium€Headspace€AnalysisŌ#†XMĆXXXĪpį)#ŌŠ š@ ŠĢ1.ą0  ąThe€Agency€emphasizes€that€all€samplers€and€analysts€using€this€procedure€must€exerciseŠ Š  Šextreme€care€when€collecting€and€analyzing€samples€with€or€without€preservation.€€TheĻpotential€for€loss€of€target€compounds€is€significant€if€samples€are€not€handled€properly.€€Š (#(# ŠĢ2.ą0  ąThe€Agency€strongly€recommends€the€use€of€the€preservation€options€available€in€theŠ $ą" Šmethod€to€prevent€loss€of€target€compounds.€€Š (#(# ŠĢ3.ą0  ąSampling€personnel€should€review€the€introductory€text€in€Section€6.0€of€the€method€andŠ `'°"% Šconsult€the€appropriate€laboratory€personnel€to€ensure€that€the€options€for€preservationĻand€addition€of€internal€standards€and€surrogates€are€carried€out€appropriately.Š (#(# ŠĢń ńŠ   +p&) Šń ńń!ńĢń!ńņ ņŌ  ŌSynopsis€of€Clarifications€to€Method€5035€„€Closed„System€Purge„and„Trap€and€ExtractionŠ ° Šfor€Volatile€Organics€in€Soil€and€Waste€Samplesó óŠ  š ŠĢ1.ą0  ąThe€Agency€recommends€that€ņņallóó€soil€samples€collected€for€volatiles€be€preserved€inŠ €Š Šsome€manner,€whenever€possible.€€For€low€concentration€samples,€generally€those€belowĻ200€ššg/kg€of€volatiles,€preservation€is€essential.€€For€samples€with€higher€concentrationsĻof€volatiles€(e.g.,€greater€than€200€ššg/kg),€the€Agency€recommends€that€unpreservedĻsamples€only€be€collected€as€a€last€resort,€and€that€the€rationale€for€not€preserving€theĻsamples€be€clearly€documented€in€a€sampling€and€analysis€plan€that€is€reviewed€andĻapproved€by€the€relevant€regulatory€authority.Š (#(# ŠĢ2.ą0  ąFor€samples€of€calcareous€soils€that€effervesce€on€contact€with€the€sodium€bisulfateŠ P  Špreservative€solution,€Ō_ŌtheŌ_Ō€Agency€recommends€that€such€strongly€reacting€samples€beĻcollected€in€a€device€such€as€the€EnCore€sampler,€stored€at€4ššC€or€less,€and€analyzedĻwithin€48€hours€of€Ō_Ōcollection.Ō_Ō€€Ō_ŌLongerŌ_Ō€holding€times€may€be€implemented€if€it€can€beĻconclusively€demonstrated€that€alternative€preservation€techniques,€such€as€freezingĻsamples€immediately€after€collection€(and€keeping€them€frozen€during€shipping€andĻstorage),€or€immediately€upon€receipt€in€the€laboratory,€does€not€compromise€sampleĻŌ_Ōintegrity.Ō_ŌŠ (#(# ŠĢ3.ą0  ąSample€vials€are€weighed€in€the€field€before€use.€€Vials€containing€methanol€are€used€forŠ pĄ Šhigh€concentration€samples.€€When€the€difference€between€the€weight€determined€at€theĻtime€that€the€vial€was€prepared€ņņin€the€laboratoryóó€and€the€weight€in€the€field€variesŠ P  Šsignificantly,€the€vial€should€not€be€used€because€the€difference€suggests€that€the€vial€isĻlosing€methanol.€€If€€both€weight€measurements€are€made€in€the€laboratory€before€use,€theĻloss€of€€0.01€g€or€more€should€be€used€as€the€point€at€which€the€vial€is€not€used.€€If€theĻinitial€weight€measurement€is€made€in€the€laboratory€and€the€subsequent€weightĻmeasurement€made€in€the€field,€or€if€both€weight€measurements€are€made€in€the€field,€theĻloss€of€€0.2€g€or€more€should€be€used€as€the€point€at€which€the€vial€is€not€used.Š (#(# ŠĢ4.ą0  ąŌ_ŌTheŌ_Ō€Agency€recommends€that€the€1:1€soil€to€solvent€ratio€be€used€as€a€default€value€(e.g.,Š Š  Š5€g€of€soil€in€a€vial€containing€5€mL€of€methanol).€€Analysts€wishing€to€employ€a€1:1€soilĻto€solvent€ratio€should€demonstrate€that€the€amount€of€solvent€is€sufficient€to€submergeĻthe€entire€plug€of€soil€in€the€vial€for€typical€soils€from€the€site€of€interest€or€a€similar€site.€ĻIf€the€amount€of€solvent€is€not€sufficient€to€cover€the€soil€plug,€additional€methanolĻshould€be€added€to€ensure€that€the€methanol€extract€can€be€removed€for€purging€and€thatĻthe€loss€of€target€compounds€to€the€sample€headspace€will€be€Ō_Ōminimized.Ō_Ō€€As€alreadyĻnoted€in€Section€6.2.2.6,€other€sample€weights€and€volumes,€resulting€in€other€soil€toĻsolvent€ratios,€are€acceptable,€provided€that€the€overall€performance€of€the€procedure€hasĻbeen€demonstrated€to€be€appropriate€Ō_ŌandŌ_Ō€appropriately€Ō_Ōdocumented.Ō_ŌŠ (#(# ŠĢą0  ąAnalysts€and€samplers€should€Ō_ŌalsoŌ_Ō€be€aware€that€the€use€of€methanol€preservationĻintroduces€a€dilution€factor€that€may€affect€the€ability€to€determine€the€analytes€of€interestĻā āat€a€specific€regulatory€level.€€The€dilution€factor€is€often€on€the€order€of€Ō_Ō50Ō_Ō€(for€a€1:1€soilŠ -P(+ Što€solvent€ratio)€or€Ō_Ō100Ō_Ō€(for€a€1:2€soil€to€solvent€ratio),€but€the€exact€dilution€factor€shouldĻbe€evaluated€in€consultation€with€the€laboratory€performing€the€analysis.Š (#(# Šā āĢŌ_Ō5.Ō_Ōą0  ąWith€regard€to€the€addition€of€surrogates€to€high€concentration€samples,€analysts€shouldŠ €Š Šfollow€the€high€concentration€procedures€as€described€in€the€method,€ignoring€theĻerroneous€statement€in€the€introductory€text€of€Section€7.3€of€the€method.Š (#(# ŠĢĢņ ņSynopsis€of€Clarifications€to€Method€6010B€„€Inductively€Coupled€Plasma„Atomic€EmissionŠ 0 € ŠSpectrometryó óŠ  p  ŠĢ1.ą0  ąThe€calibration€range€check€described€in€Section€7.2.5.4€employs€an€acceptance€criterionŠ P  Šof€šš10%,€allowing€small€excursions€below€and€above€the€predicted€response€for€theĻhighest€standard.Š (#(# ŠĢ2.ą0  ąAs€the€result€of€an€editorial€error,€the€discussion€in€Section€8.6.1.2€duplicates€that€inŠ Ą ŠSection€8.6.1.1.€€Only€one€check€standard€is€to€be€run€in€Section€8.6.1,€and€evaluatedĻusing€the€criterion€in€Section€8.6.1.1.Š (#(# ŠĢ3.ą0  ąThere€is€an€editorial€error€in€the€text€in€Section€8.6.1.3.€€The€intended€text€for€SectionŠ €Š Š8.6.1.3€is€provided€below,€and€will€be€incorporated€into€the€next€revision€of€the€method.Š (#(# ŠĢą0  ąņņą ` ą8.6.1.3ą ø ą€€The€results€of€the€calibration€blank€are€to€be€less€than€three€times€theŠ P  Šlaboratory's€IDL€for€each€analyte.€€If€this€is€not€the€case,€the€reason€for€the€out-of-controlĻcondition€must€be€found€and€corrected,€and€the€affected€samples€must€be€reanalyzed.€€IfĻthe€laboratory€consistently€has€concentrations€greater€than€three€times€the€IDL,€then€theĻIDL€may€be€indicative€of€an€estimated€IDL€and€should€be€re-evaluated.€€If€the€blank€isĻless€than€1/10th€of€the€concentration€of€the€lowest€sample€of€the€batch,€the€analysis€needĻnot€be€terminated.Š (#(# ŠóóĢĢņ ņSynopsis€of€Clarifications€to€Method€8000B€„€Determinative€Chromatographic€Separationsó óŠ Ą! ŠĢ1.ą0  ąCalibrations€employing€least€squares€regressions€may€use€a€weighting€factor€ofŠ  #š! Š(1/concentration)€or€(1/concentrationņņ2óó)€in€place€of€the€factor€of€(1/SDņņ2óó)€that€is€discussed€inŠ $ą" Šthe€method.€€The€relative€standard€error€(RSE)€is€a€useful€measure€of€the€goodness€of€fitĻof€a€calibration€model€and€the€Agency€encourages€its€use,€employing€the€same€numericalĻlimits€provided€in€many€methods€for€the€relative€standard€deviation€(RSD).€€There€is€aĻtypographical€error€in€the€third€equation€on€page€21€of€the€method.€€The€weighting€factorĻ(1/SDņņ2óó)€should€not€appear€in€that€equation.€Š@)$'(#(# ŠĢ2.ą0  ąReporting€data€from€dual„column€chromatographic€analyses€is€an€issue€that€should€beŠ  +p&) Šaddressed€in€the€sampling€and€analysis€plan.€€In€the€absence€of€such€a€plan€that€discussesĻthis€issue,€the€Agency€has€provided€a€default€approach€in€Method€8000B.€€That€approachĻstipulates€that€in€instances€when€the€relative€percent€difference€between€two€valuesŠ š-@), Šexceeds€40%€ņņandóó€there€is€no€evidence€of€chromatographic€anomalies€or€interferences,Š ° Šthen€the€higher€value€is€reported€and€the€data€user€is€notified€of€the€possible€problem.€ĻWhen€interferences€or€anomalies€are€present,€the€analyst€should€take€reasonable€steps€toĻresolve€the€problems,€and€the€default€approach€provides€the€regulated€entity€with€anĻincentive€to€have€such€problems€resolved.€€When€the€difference€is€less€that€40%,€theĻchoice€of€which€value€to€report€is€a€project„specific€issue.Š (#(# ŠĢ3.ą0  ąSection€8.1€of€Method€8000B€contains€an€editorial€error.€€The€Agency€is€not€encouragingŠ @  Šinstrument„specific€QC€limits,€but€does€recommend€method„specific€QC€limits.€€EachĻlaboratory€is€expected€to€operate€a€formal€quality€assurance€program.€€The€sentenceĻindicating€that€expectation€was€deleted€from€Section€8.1€in€error€from€the€Final€UpdateĻIII€revision.€€Section€8.1€should€read€as€follows:Š (#(# ŠĢą0  ąņņą ` ą8.1ą ø ąRefer€to€Chapter€One€for€specific€quality€control€procedures.€€EachŠ ą0  Šlaboratory€using€SW„846€methods€should€maintain€a€formal€quality€assurance€program.€ĻThe€development€of€in„house€QC€limits€for€each€method€is€encouraged,€as€described€inĻSec.€8.7.€€In€general,€the€following€QC€requirements€pertain€to€all€the€determinativeĻmethods€listed€in€Sec.€1.1€unless€superseded€by€specific€requirements€provided€in€eachĻdeterminative€method.Š (#(# ŠóóĢ4.ą0  ąSection€8.5€of€Method€8000B€specifies€a€frequency€of€one€MS/MSD€pair€for€every€20Š pĄ Šfield€samples.€€This€is€a€default€frequency€that€may€be€adjusted€in€the€context€of€aĻsampling€and€analysis€plan€approved€by€the€relevant€regulatory€authority.€€Further,€theĻpurpose€of€the€MS/MSD€analyses€is€to€provide€information€on€the€applicability€of€theĻanalytical€method€to€the€sample€matrix.€€The€Agency€stresses€that€the€appropriate€use€ofĻMS/MSD€results€is€to€evaluate€ņņmethodóó€performance€in€the€matrix€of€interest,€notŠ  p Šņņlaboratoryóó€performance.Š`(#(# ŠĢĢņ ņSynopsis€of€Clarifications€to€Method€8082€„€Polychlorinated€Biphenyls€(PCBs)€by€GasŠ ą0 ŠChromatographyó óŠ Š  ŠĢ1.ą0  ąSection€8.3.€of€Method€8082€addresses€the€initial€demonstration€of€proficiency.€€This€testŠ °"  Šis€to€be€conducted€by€each€laboratory€prior€to€the€analysis€of€samples,€and€serves€toĻdemonstrate€the€laboratory's€ability€to€perform€the€method€in€a€clean€matrix.€€SectionĻ8.3.1.1€states€that€the€QC€reference€sample€be€analyzed€at€a€frequency€of€once€for€eachĻgroup€of€up€to€20€field€samples.€€This€section€is€clearly€in€error,€since€performance€of€theĻinitial€demonstration€is€not€tied€to€a€specific€group€of€field€samples.€€The€specificationsĻfor€the€frequency€of€the€initial€demonstration€are€correctly€provided€in€Section€8.3.1.Š (#(# ŠĢ2.ą0  ąSection€8.3.1.2€of€Method€8082€provides€quality€control€acceptance€criteria€of€80„120%Š 0*€%( Šrecovery€for€the€initial€demonstration€of€proficiency.€€The€Agency€recognizes€that€theseĻlimits€conflict€with€the€more€general€guidance€provided€in€Method€8000€regarding€theĻinitial€demonstration.€€As€specifically€described€in€Method€8000,€limits€of€70„130%Ļrecovery€should€be€used€by€the€laboratory€as€ņņinterim€guidanceóó€while€the€laboratoryŠ š-@), Šcollects€enough€data€to€generate€in„house€control€limits€for€the€initial€demonstration€ofĻproficiency.€€Once€such€limits€are€generated,€the€70„130%€guidance€limits€no€longerĻapply.€€The€Agency€recommends€that€analysts€use€the€approach€described€in€MethodĻ8000€in€place€of€the€discussion€of€Section€8.3.1.2€in€Method€8082.Š (#(# ŠŠ  pĄ ŠŲŲÖ€ąÖą@©©$ģąņ ņAttachment€2ó óˆŠ ° Šą@  ģąņ ņDetailed€Discussion€of€the€Clarifications€to€Certain€Update€III€SW„846€Methodsó óˆŠ  š Šą@SS&ģąņ ņJuly€1998ó óˆŠ ą ŠĢĢą  ąThis€attachment€contains€a€detailed€discussion€of€the€clarifications€to€certain€portions€ofĻthe€following€SW„846,€Final€Update€III€methods:ĢĢÓ-°,X‚X4ø —X°,X›X-Óą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦2[Żš"šą0 4 ąŻ  ŻMethod€3550B,€Ultrasonic€ExtractionŻƒ"‡¦2[M[ŻŒŠ0 €4(#4(# ŠŒŻ  ŻĢą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦ī[Żš"šą0 4 ąŻ  ŻMethod€5021,€Volatile€Organic€Compounds€in€Soils€and€Other€Solid€Matrices€UsingŠ `  ŠEquilibrium€Headspace€AnalysisŻƒ"‡¦ī[ \ŻŒŠ 4(#4(# ŠŒŻ  ŻĢą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦]Żš"šą0 4 ąŻ  ŻMethod€5035,€Closed„System€Purge„and„Trap€and€Extraction€for€Volatile€Organics€inŠ ą0  ŠSoil€and€Waste€SamplesŻƒ"‡¦]]ŻŒŠ 4(#4(# ŠŒŻ  ŻĢą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦^Żš"šą0 4 ąŻ  ŻMethod€6010B,€Inductively€Coupled€Plasma„Atomic€Emission€SpectrometryŻƒ"‡¦^)^ŻŒŠ°4(#4(# ŠŒŻ  ŻĢą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦ģ^Żš"šą0 4 ąŻ  ŻMethod€8000B,€Determinative€Chromatographic€SeparationsŻƒ"‡¦ģ^_ŻŒŠą4(#4(# ŠŒŻ  ŻĢą  ąŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦¼_Żš"šą0 4 ąŻ  ŻMethod€8082,€Polychlorinated€Biphenyls€(PCBs)€by€Gas€ChromatographyŻƒ"‡¦¼_×_ŻŒŠpĄ4(#4(# ŠŒŻ  ŻÓ- °,X›X°,X‚X4ø —X-ÓĢĢņ ņŌ  ŌMethod€3550B€„€Ultrasonic€Extractionó óŠ @ ŠĢą  ąSection€1.5€of€Method€3550B€states€that€ultrasonic€extraction€may€not€be€appropriate€forĻthe€extraction€of€organophosphorus€pesticides€(OPPs).€€Section€1.7€of€the€method€states€that€theĻmethod€is€not€appropriate€for€applications€which€require€high€extraction€efficiency€for€allĻanalytes€at€very€low€concentrations.€€The€Agency€recognizes€that€these€statements€and€similarĻdiscussions€of€the€OPP€issue€in€Methods€3500B€and€8141A€have€raised€concerns€amongĻlaboratories€and€regulators€alike.ĢĢą  ąThe€Agency€added€these€statements€to€Method€3550B€in€response€to€long„standingĻconcerns€about€the€extraction€efficiency€of€the€technique€in€general,€and€based€on€data€on€OPPsĻthat€were€generated€in€1987€in€connection€with€Method€8140.€€The€Agency€has€performed€anĻextensive€review€of€a€variety€of€studies,€some€published€in€the€open€literature€and€someĻconducted€by€Agency€researchers€or€under€contract€to€the€Agency.€€Based€on€that€review,€thereĻare€few€well„designed€studies€comparing€the€use€of€ultrasonic€extraction€to€any€other€extractionĻtechnique€that€address€what€the€Agency€considered€"very€low€concentrations"€when€it€added€theĻlanguage€to€Method€3550B.€€A€few€of€the€published€studies€have€looked€at€concentrations€as€lowĻas€100€ššg/kg,€but€most€of€the€studies€have€been€performed€on€samples€containing€part€perĻmillion€(ppm€or€mg/kg)€concentrations.€€In€addition,€even€the€best€of€these€studies€were€notĻdesigned€to€permit€meaningful€statistical€evaluations€of€the€results.€€For€example,€several€studiesĻcompared€duplicate€or€sometimes€triplicate€ultrasonic€extractions€to€single€extractions€by€anotherĻtechnique.€€Several€of€the€studies€used€different€solvents€when€comparing€different€techniques,Ļsuch€that€the€effect€of€the€solvent€cannot€be€distinguished€from€the€effect€of€the€extractionŠ ą.0*- Štechnique€itself.€€In€other€studies,€the€spiking€levels€were€not€consistent€across€the€methods€thatĻwere€evaluated.€€The€end€result€of€these€shortcomings€is€that,€while€the€results€for€ultrasonicĻextraction€may€"look"€better€or€worse€than€another€technique€to€some€observers,€meaningfulĻstatistical€comparisons€cannot€be€performed.ĢĢą  ąExtraction€techniques€such€as€ultrasonic€extraction€employ€relatively€large€volumes€ofĻorganic€solvents.€€For€the€past€several€years,€the€Agency€as€a€whole€has€been€working€to€reduceĻthe€use€of€solvents€in€its€own€laboratories€and€in€the€analytical€methods€associated€with€itsĻvarious€regulatory€programs.€ĢĢą  ąTherefore,€in€response€to€the€concerns€raised€about€this€method,€the€Agency€wishes€toĻclarify€its€intentions€with€regard€to€ultrasonic€extraction.€€First,€the€Agency€recommends€that€theĻanalyst€demonstrate€that€ņņanyóó€extraction€technique€is€effective€for€the€analytes€of€interest,€at€theŠ š@  Šlevels€of€interest,€in€the€matrix€of€interest.€€Many€regulatory€limits€associated€with€the€RCRAĻprogram€are€in€the€high€part€per€billion€(ppb)€range€or€higher.€€However,€the€Agency€recognizesĻthat€many€analyses€are€performed€to€determine€the€concentrations€of€analytes€of€interest€that€areĻpresent€in€the€low€part€per€billion€range€and€even€the€sub€part€per€billion€range.€€In€those€cases,Ļthe€performance€demonstration€should€focus€on€similar€low€ppb€levels.€€The€performanceĻdemonstrations€involved€are€those€already€described€in€the€SW„846€methods,€and€include€theĻinitial€demonstration€of€proficiency,€the€laboratory€control€sample,€and€the€matrix€spike€andĻmatrix€spike€duplicate.ĢĢą  ąThe€Agency€also€acknowledges€that€its€initial€concerns€about€the€use€of€ultrasonicĻextraction€for€OPPs€may€be€due€to€other€causes.€€In€the€next€revision€of€the€methods,€the€AgencyĻplans€to€remove€the€language€in€question€from€Sections€1.5€and€1.7€of€Method€3550€andĻcorresponding€language€in€Method€3500.€€Until€that€time,€the€Agency€advises€analysts€to€viewĻthe€current€language€as€a€caution,€not€a€prohibition,€regarding€the€use€of€this€technique€and€to€useĻthe€existing€performance€measures€described€in€SW„846€to€demonstrate€the€performance€of€anyĻextraction€technique€at€the€levels€of€interest€for€a€specific€project.€€The€Agency€plans€to€addĻlanguage€to€Method€3500€stressing€the€importance€of€demonstrating€the€performance€of€ņņanyóóŠ ą0 Šextraction€technique€at€concentrations€relevant€to€the€analysis€of€field€samples.ĢĢĢņ ņMethod€5021€„€Volatile€Organic€Compounds€in€Soils€and€Other€Solid€Matrices€UsingŠ  #š! ŠEquilibrium€Headspace€Analysisó óŠ $ą" ŠĢą  ąSections€6.1,€6.3,€7.4.2.3,€and€7.5€of€Method€5021€address€the€collection€and€analysis€ofĻsamples€that€are€not€preserved€in€the€field.€€The€text€in€these€sections€has€led€to€concerns€and/orĻconfusion€regarding€the€Agency's€intent€with€regard€to€sample€collection€and€preservation.€ĻThese€concerns€have€been€accentuated€by€the€fact€that€the€equilibrium€headspace€procedure€isĻless€commonly€used€by€environmental€laboratories€than€other€techniques€for€the€preparation€ofĻsamples€for€the€analysis€of€volatile€constituents.ĢĢą  ąThe€Agency€emphasizes€that€all€samplers€and€analysts€using€this€procedure€must€exerciseĻextreme€care€when€collecting€and€analyzing€samples€with€or€without€preservation.€€The€potentialĻfor€loss€of€target€compounds€is€significant€if€samples€are€not€handled€properly.€€The€AgencyŠ ą.0*- Šstrongly€recommends€the€use€of€the€preservation€options€available€in€the€method€to€prevent€lossĻof€target€compounds.€€EPA€also€plans€to€revise€parts€of€Sections€6€and€7€in€a€future€revision€ofĻthe€method€to€clarify€these€issues.€€Sampling€personnel€should€review€the€introductory€text€inĻSection€6.0€of€the€method€and€consult€the€appropriate€laboratory€personnel€to€ensure€that€theĻoptions€for€preservation€and€addition€of€internal€standards€and€surrogates€are€carried€outĻappropriately.ĢĢĢņ ņMethod€5035€„€Closed„System€Purge„and„Trap€and€Extraction€for€Volatile€Organics€in€SoilŠ 0 € Šand€Waste€Samplesó óŠ  p  ŠĢņ ņItem€1€„€Preservation€of€High€Concentration€Samplesó óŠ P  ŠĢą  ąSections€6.1.2,€6.2.3,€and€7.3.1€of€Method€5035€address€the€collection€and€analysis€ofĻhigh€concentration€samples€that€are€not€preserved€in€the€field.€€The€text€in€these€sections€has€ledĻto€concerns€and/or€confusion€regarding€the€Agency's€intent€in€Method€5035.€€By€way€ofĻclarification,€the€Agency€stresses€that€these€sections€describe€ņņonlyóó€those€samples€that€canŠ ° Šreasonably€be€expected€to€contain€greater€than€200€ššg/kg€of€volatile€target€compounds.€€TheĻdiscussion€must€ņņnotóó€be€construed€to€suggest€that€low€concentration€soil€and€waste€samples€(e.g.,Š ą Šthose€with€less€than€200€ššg/kg)€should€be€collected€without€the€use€of€some€preservative.€€ĢĢą  ąUnder€the€best€of€circumstances,€all€samples,€including€those€with€high€concentrations€ofĻvolatile€constituents,€should€be€preserved€in€some€manner.€€However,€the€preservation€techniquesĻare€expected€to€differ€for€different€concentration€ranges€and€with€different€determinativeĻmethods.€€Collecting€samples€in€vials€containing€an€aqueous€sodium€bisulfate€solution€andĻanalyzing€them€using€the€closed„system€purge„and„trap€described€in€Method€5035€represents€oneĻsuch€preservation€approach.€€However,€this€approach€is€not€practical€for€samples€containingĻconcentrations€of€analytes€over€the€calibration€range€of€the€determinative€technique,€since€theĻsample€cannot€be€diluted,€nor€can€a€smaller€sample€aliquot€be€removed€from€the€original€sampleĻvial€without€the€loss€of€volatile€constituents.€ĢĢą  ąŌ_ŌGivenŌ_Ō€that€the€purge„and„trap€device€used€in€Method€5035€is€a€closedŌ_Ō„system,Ō_Ō€it€is€notĻpossible€to€dilute€the€original€sample€when€the€observed€concentration€exceeds€the€calibrationĻrange€of€the€method.€€The€200€ššg/kg€cutoff€that€distinguishes€"low€concentration"€from€"highĻconcentration"€samples€is€based€on€the€commonly€used€upper€limit€of€the€calibration€range€forĻMethod€8260,€a€GC/MS€procedure.€€This€upper€limit€is€somewhat€instrument„dependent.€€SomeĻlaboratories€may€be€able€to€establish€a€linear€range€that€exceeds€200€ššg/kg€on€some€instruments.€ĻThe€upper€limit€is€also€method„dependent,€and€other€determinative€methods€that€may€be€used€inĻconjunction€with€Method€5035€may€have€different€calibration€ranges€compared€to€Method€8260.€ĻThus,€there€may€be€situations€in€which€samples€with€less€than€200€ššg/kg€of€any€volatile€analyteĻmay€cause€difficulties€for€some€laboratories€using€some€determinative€methods.ĢĢą  ąMethod€5035€includes€procedures€for€collecting€high€concentration€soil€and€wasteĻsamples€in€a€vial€containing€methanol€or€other€water„miscible€solvent€as€a€preservative.€€Ō_ŌTheŌ_ŌĻAgency€recognizes€that€other€preservation€techniques€are€available€or€may€become€available€inĻthe€Ō_Ōfuture.Ō_Ō€€€Ō_ŌForŌ_Ō€example,€individuals€may€use€sealed€sampling€devices,€such€as€the€EnCoreŠ ą.0*- Šsampler€described€in€the€method,€to€preserve€high€concentration€samples,€when€Ō_Ōappropriate.Ō_Ō€ĻWhile€the€Agency€ņņstronglyóó€recommends€that€some€type€of€preservation€technique€be€appliedŠ  š Šwhenever€possible,€the€Agency€recognizes€that€there€are€instances€where€preservation€is€notĻpractical€for€such€high€concentration€samples.€€In€these€instances,€the€Agency€believes€that€theĻpotential€loss€of€volatiles€from€such€high€concentration€samples€may€be€an€acceptable€risk,Ļprovided€that€the€samplers€and€the€laboratory€have€taken€reasonable€steps€to€minimize€the€loss€ofĻvolatiles.€€To€that€end,€the€Agency€recommends€that€the€collection€of€unpreserved€samples€ņņonlyóóŠ P   Šbe€considered€for€those€materials€that€can€reasonably€be€expected€to€contain€high€levels€ofĻvolatiles,€ņņandóó€that€the€rationale€for€not€preserving€the€samples€be€clearly€documented€in€aŠ 0 € Šsampling€and€analysis€plan€that€is€reviewed€and€approved€by€the€relevant€regulatory€authority.€ĻFurther,€the€Agency€recommends€that€the€laboratory€be€consulted€prior€to€sample€collection€toĻdetermine€the€relevant€cutoff€concentration€for€the€specific€determinative€method€to€beĻemployed.€€Whatever€approach€is€employed,€the€ultimate€data€user€should€be€advised€of€theĻpreservation€approach,€and€ņņmustóó€be€advised€of€those€instances€in€which€no€preservation€wasŠ ą0  Šemployed.ĢĢņ ņItem€2€„€Holding€Time€for€Samples€Collected€in€the€EnCore€Sampleró óŠ ° ŠĢą  ąSection€6.2.1.8€of€Method€5035€provides€a€48„hour€holding€time€for€samples€collected€inĻthe€EnCore€sampler.€€At€the€time€that€Method€5035€was€promulgated,€the€Agency€hadĻinsufficient€data€on€samples€collected€with€this€device€to€justify€a€longer€holding€time.€€Since€theĻpromulgation€of€the€method,€the€Agency€has€become€aware€of€additional€data€that€may€indicateĻthat€a€longer€holding€time€is€appropriate.€€Ō_ŌForŌ_Ō€example,€test€data€submitted€to€the€AgencyĻindicate€that€a€7„day€holding€time€may€be€acceptable€for€six€common€volatile€compounds€usingĻthe€stainless€steel€EnCore€sampler,€although€the€stainless€steel€version€of€the€EnCore€sampler€isĻno€longer€manufactured.€€The€Agency€is€reviewing€additional€holding€time€data€for€the€nylonĻversion€of€the€EnCore€sampler.€€If€the€results€from€this€review,€and€the€review€of€anyĻsubsequently€developed€data,€are€sufficient€to€support€a€longer€holding€time,€the€Agency€willĻincorporate€that€change€into€a€future€method€Ō_Ōrevision.Ō_ŌĢĢą  ąThe€Agency€is€aware€that€for€calcareous€soils,€such€as€those€found€in€parts€of€the€southernĻU.S.,€the€use€of€the€sodium€bisulfate€preservative€solution€is€not€appropriate,€since€the€calciumĻcarbonate€in€the€soil€will€effervesce€in€the€presence€of€the€preservative€solution,€potentiallyĻsplattering€the€sample€onto€the€vial€threads,€driving€the€volatile€analytes€out€of€the€solution,€etc.€€ĻThis€problem€is€addressed€in€the€note€in€Section€6.2.1.2,€which€recommends€that€samples€thatĻvigorously€react€with€the€preservative€solution€be€collected€in€vials€without€the€preservative.ĢĢą  ąThis€recommendation€has€led€to€concerns€about€the€integrity€of€such€samples.€€Ō_ŌTherefore,Ō_ŌĻthe€Agency€additionally€recommends€that€such€strongly€reacting€samples€be€collected€in€a€deviceĻsuch€as€the€EnCore€sampler,€stored€at€4ššC€or€less,€and€analyzed€within€48€hours€of€Ō_Ōcollection.Ō_Ō€ĻŌ_ŌLongerŌ_Ō€holding€times€may€be€implemented€if€it€can€be€conclusively€demonstrated€that€alternativeĻpreservation€techniques,€such€as€freezing€samples€immediately€after€collection€(and€keepingĻthem€frozen€during€shipping€and€storage),€or€immediately€upon€receipt€in€the€laboratory,€does€notĻcompromise€sample€Ō_Ōintegrity.Ō_ŌĢā āŠ š-@), Šą  ąŌ_ŌAnotherŌ_Ō€possible€alternative€to€the€EnCore€sampler€for€calcareous€soils€is€the€use€of€glassĻā ā40€mL€VOA€vials€containing€only€organic€free€reagent€water€(no€acid).€€Samples€would€beĻcollected€using€a€cut„off€syringe€and€placed€into€the€VOA€vials€containing€the€water.€€The€vialsĻwould€then€be€frozen€to€preserve€the€samples.€€To€prevent€the€glass€vials€from€breaking€due€toĻthe€expansion€of€the€water€during€the€freezing€process,€the€vials€would€be€stored€at€an€angle€toĻallow€the€water€to€expand.€€The€Agency€has€no€holding€time€data€or€additional€sample€storageĻinformation€at€this€time€to€support€the€use€of€this€technique.€€However,€this€approach€may€beĻacceptable€for€holding€times€longer€than€48€hours€if€it€can€be€conclusively€demonstrated€that€theĻtechnique€does€not€compromise€the€integrity€of€the€Ō_Ōsamples.Ō_ŌĢĢŌ  Ōņ ņItem€3€„€Weighing€Sample€Vials€in€the€Fieldó óŠ `  ŠĢą  ąSection€6.1.3.4€of€Method€5035€contains€a€note€that€describes€weighing€the€vials€a€secondĻtime€after€they€are€prepared€and€before€they€are€used.€€The€results€of€the€second€weighing€areĻcompared€to€the€weight€that€was€determined€in€the€laboratory€in€Section€6.1.1.6.€€As€described€inĻthat€note,€a€difference€of€€>€0.01€g€between€these€two€weights€indicates€the€loss€of€methanol€fromĻthe€vial€(either€as€liquid€or€vapors)€and€indicates€that€such€vials€should€not€be€used€to€collectĻsamples.ĢĢą  ąThe€specification€of€0.01€g€was€a€typographical€error,€and€should€reflect€a€value€of€0.1€g.€ĻThe€method€developer€provided€the€0.1€g€specification,€based€on€performing€the€secondĻweighing€in€the€laboratory€before€proceeding€to€the€field.€€The€Agency€recognizes€that€there€isĻsome€confusion€over€this€second€weighing€step€and€where€it€is€to€be€performed.€€If€both€weightĻmeasurements€are€made€in€the€laboratory€before€use,€the€loss€of€€0.01€g€or€more€should€be€usedĻas€the€point€at€which€the€vial€is€not€used.€€If€the€initial€€weight€measurement€is€made€in€theĻlaboratory€€and€the€subsequent€weight€measurement€made€in€the€field,€or€if€both€weightĻmeasurements€are€made€in€the€field,€the€loss€of€€0.2€g€or€more€should€be€used€as€the€point€atĻwhich€the€vial€is€not€used.ĢĢŌ  Ōņ ņItem€4€„€Dilution€Factors€Attendant€in€Methanol€Preservation€of€Soil€Samplesó óŠ ą0 ŠĢą  ąSection€2.2.2€of€Method€5035€describes€that€soil€and€a€water„miscible€solvent€such€asĻmethanol€are€combined€in€a€1:1€ratio€Ō_Ō(i.e.,Ō_Ō€5€g€of€soil€in€5€mL€of€Ō_Ōmethanol)Ō_Ō€in€the€preservation€ofĻhigh€concentration€soil€samples.€€In€contrast,€Section€6.1.3€of€the€method€describes€a€1:2€ratioĻŌ_Ō(i.e.,Ō_Ō€5€g€of€soil€in€10€mL€of€methanol).€€The€conflicting€information€is€compounded€by€aĻtypographical€error€in€Section€Ō_Ō6.2.2,Ō_Ō€which€states€that€the€dilution€factor€resulting€from€the€use€ofĻmethanol€as€a€preservative€exceeds€1000.€€The€correct€value€for€the€dilution€factor€is€100,€andĻstems€from€the€use€of€the€1:2€soil€to€methanol€Ō_ŌratioŌ_Ō€from€Section€6.1.3€Ō_ŌandŌ_Ō€the€addition€of€atĻmost€100€ššL€of€the€methanol€extract€to€5€mL€of€reagent€water€for€purging.ĢĢą  ąŌ_ŌInŌ_Ō€addition,€new€data€suggests€that€a€1:1€soil€to€solvent€ratio€may€be€appropriate€whenĻattempting€to€get€better€method€sensitivity.€€These€data€were€not€available€at€the€time€thatĻMethod€5035€was€promulgated.€€The€Agency€will€contact€the€method€developer€to€obtain€theseĻdata€and€review€them.€€The€method€will€be€revised€in€the€future,€if€appropriate.€€The€1:1€soil€toĻsolvent€ratio€appears€to€work€well€for€solid€samples€(e.g.,€sandy€soil)€that€do€not€expand€to€soakĻup€the€methanol€when€it€is€added.€€On€the€other€hand,€many€samples,€such€as€those€with€a€highŠ ą.0*- Šorganic€content,€may€expand€and€soak€up€all€the€free€methanol,€making€it€impossible€to€removeĻmethanol€extract€from€the€sample€container€for€purging€purposes.€€Moreover,€if€the€solvent€doesĻnot€cover€all€of€the€soil,€volatile€analytes€will€escape€into€the€headspace€and€not€be€captured€inĻthe€aliquot€of€solvent€removed€from€the€vial€for€Ō_Ōanalysis.Ō_ŌĢĢą  ąŌ_ŌWhileŌ_Ō€the€Agency€regrets€the€conflicting€soil€to€solvent€ratios€in€Section€2.2.2€and€6.1.3,€Ļthe€method€does€Ō_ŌindicateŌ_Ō€in€Section€6.2.2.6€that€other€sample€weights€and€volumes€of€methanolĻmay€be€employed,€"provided€that€the€analyst€can€demonstrate€that€the€sensitivity€of€the€overallĻanalytical€procedure€is€appropriate€for€the€intended€application."€€€€This€should€include€ensuringĻthat:ĢĢŻ‚"‡¦’ŻŻ  ŻŅ°ŅŻ‚"‡¦Č¦Żš"šą0 ` ąŻ  Żthe€volume€of€solvent€used€is€sufficient€to€cover€the€sample€solids,€andŻƒ"‡¦Č¦ń¦ŻŒŠP ` (#` (# ŠŒŻ  ŻŻ‚"‡¦’ŻŻ  ŻŻ‚"‡¦Ŗ§Żš"šą0 ` ąŻ  Żthe€analyst€accurately€calculates€and€accounts€for€the€actual€soil€to€solvent€ratioŠ š@  Šused€in€all€subsequent€calculations.Żƒ"‡¦Ŗ§Å§ŻŒŠ ` (#` (# ŠŒŻ  ŻĢŅ°Ņą  ąThus,€the€Agency€recommends€that€the€Ō_Ō1:1Ō_Ō€soil€to€solvent€ratio€be€used€as€a€default€value.€ĻAnalysts€wishing€to€employ€a€1:1€soil€to€solvent€ratio€should€demonstrate€that€the€amount€ofĻsolvent€is€sufficient€to€submerge€the€entire€plug€of€soil€in€the€vial€for€typical€soils€from€the€site€ofĻinterest€or€a€similar€site.€€Ō_ŌIfŌ_Ō€the€amount€of€solvent€is€not€sufficient€to€cover€the€soil€plug,Ļadditional€methanol€should€be€added€to€ensure€that€the€methanol€extract€can€be€removed€forĻpurging€and€that€the€loss€of€target€compounds€to€the€sample€headspace€will€be€Ō_Ōminimized.Ō_Ō€€TheĻAgency€notes€that€such€a€demonstration€need€not€be€made€for€every€site€or€soil€matrix,€but€thatĻthe€soil€to€solvent€ratio€be€considered€at€some€point€prior€to€the€collection€of€samples.ĢĢŌ_ŌŌ_Ōą  ąThe€Agency€also€wishes€to€point€out€that€the€dilution€factor€discussion€in€Section€6.2.2Ļshould€be€considered€in€the€context€of€the€combination€of€sampling,€preparative,€andĻdeterminative€procedures€employed€for€each€project.€€Analysts€and€samplers€should€be€awareĻthat€the€use€of€methanol€preservation€introduces€a€dilution€factor€that€may€affect€the€ability€toĻdetermine€the€analytes€of€interest€at€a€specific€regulatory€level.€€That€dilution€factor€is€often€onĻthe€order€of€50€(for€a€1:1€soil€to€solvent€ratio)€or€100€(for€a€1:2€soil€to€solvent€ratio),€but€the€exactĻdilution€factor€should€be€evaluated€in€consultation€with€the€laboratory€performing€the€Ō_Ōanalysis.Ō_ŌĢĢņ ņŌ  ŌItem€5€„€Discrepancy€Regarding€the€Addition€of€Surrogatesó óŠ °"  ŠĢą  ąIn€reviewing€Method€5035,€the€Agency€noted€a€discrepancy€in€the€introductory€text€ofĻSection€7.3.€€That€text€summarizes€the€high€concentration€sample€preparation€procedure€andĻstates€that€an€aliquot€of€the€sample€extract€is€added€to€reagent€water€containing€the€surrogatesĻand,€if€applicable,€the€internal€standards.€€That€introductory€text€is€in€error,€since€the€detailedĻdescription€of€the€procedure€provided€in€the€subsequent€sections,€particularly€7.3.3.€and€7.3.4,Ļclearly€states€that€the€surrogates€are€added€to€the€vial€containing€the€soil€sample.€€The€AgencyĻregrets€this€error€and€recommends€that€the€analyst€follow€the€specific€procedures€described€in€theĻmethod€and€ignore€the€discrepancy€in€the€introductory€text.€ĢĢā āŠ -P(+ ŠŌ  Ōā āņ ņMethod€6010B€„€Inductively€Coupled€Plasma„Atomic€Emission€Spectrometryó óŠ ° ŠĢņ ņItem€1€„€Calibration€Range€Check€Proceduresó óŠ ą ŠĢą  ąSection€7.2.5.4€of€Method€6010B€describes€the€procedures€to€be€employed€to€establishĻthe€upper€limit€of€the€dynamic€range€of€an€ICP€instrument€employed€for€metals€analyses.€€AsĻdescribed€in€that€section,€a€minimum€of€three,€and€preferably€five,€standards€at€differentĻconcentrations€are€analyzed.€€One€of€those€standards€should€be€near€the€upper€limit€of€theĻdynamic€range.€€The€Agency€recognizes€that€there€is€some€confusion€regarding€the€application€ofĻthe€QC€acceptance€criterion€of€10%€that€is€provided€in€Section€7.2.5.4€and€wishes€to€clarify€itsĻintentions.ĢĢą  ąThe€Agency's€original€concerns€stem€from€the€often€observed€behavior€of€ICPĻinstruments€wherein€the€instrument€response€begins€to€level€off€at€higher€concentrations€of€theĻanalytes€of€interest.€€Therefore,€Section€7.2.5.4€instructs€the€analyst€to€run€the€series€of€three€toĻfive€standards€to€establish€the€linear€range.€€The€analyst€is€expected€to€use€the€responses€from€allĻņņbutóó€the€highest€standard€to€construct€a€linear€calibration€line.€€The€line€then€is€extrapolated€pastŠ ° Šthe€concentration€of€the€highest€standard.€€The€results€from€the€highest€standard€are€compared€toĻthe€extrapolated€line,€in€order€to€determine€if€the€calibration€is€sufficiently€linear€up€to€theĻconcentration€of€that€highest€standard.€€The€Agency€established€an€acceptance€criterion€of€10%Ļfor€the€difference€between€the€predicted€(extrapolated)€and€observed€responses€for€that€highestĻstandard.€€The€Agency€intended€the€criterion€to€be€šš10%€of€the€predicted€response,€therebyĻallowing€small€excursions€below€ņņandóó€above€the€prediction.€€The€Agency€intends€to€clarify€itsŠ P  Šintentions€in€a€subsequent€revision€of€the€method€and€recommends€that€analysts€employ€theĻšš10%€criterion.ĢĢņ ņItem€2€„€Use€of€Calibration€Verification€Check€Standardsó óŠ ` ŠĢą  ąSection€8.6.1€of€Method€6010B€describes€the€use€of€several€types€of€standards€to€check€orĻverify€both€the€initial€calibration€of€an€instrument€and€the€continuing€(daily)€calibration.€€SectionĻ8.6.1.2€discusses€the€comparison€of€a€"check€standard"€to€its€expected€value.€€The€Agency€isĻaware€that€there€are€concerns€about€the€meaning€of€this€section,€particularly€in€relation€to€the€textĻin€Section€8.6.1.1.€€At€issue€is€the€suggestion€that€Section€8.6.1.2€requires€that€an€ņņadditionalóóŠ °"  Šcheck€standard€be€analyzed€beyond€that€which€is€already€discussed€in€Section€8.6.1.1.€€ĢĢą  ąThis€is€not€the€Agency's€intention.€€The€Agency€realizes€that€this€confusion€is€the€result€ofĻan€editorial€error€in€the€Update€III€version€of€the€method,€in€that€the€two€sections€describe€theĻsame€check€of€the€calibration.€€As€a€result,€the€Agency€recommends€that€the€analysts€run€theĻcheck€standard€described€in€Section€8.6.1€itself,€following€either€an€initial€or€a€daily€calibration.€ĻThe€acceptance€criterion€provided€in€Section€8.6.1.1€should€be€used€to€evaluate€the€checkĻstandard€results€and€the€text€in€Section€8.6.1.2€can€be€logically€ignored.€€The€Agency€plans€toĻcorrect€this€editorial€error€in€the€next€revision€of€the€method.Ģā āŠ ,`'* ŠŌ  Ōā āņ ņItem€3€„€Evaluation€of€the€Calibration€Blankó óŠ ° ŠĢą  ąSection€8.6.1.3€of€Method€6010B€describes€the€evaluation€of€the€calibration€blank€that€isĻanalyzed€immediately€after€the€daily€calibration,€after€every€10€samples,€and€at€the€end€of€theĻanalytical€run,€as€specified€in€Section€8.6.1.€€In€response€to€public€comments€received€inĻconjunction€with€the€proposal€of€Update€III,€the€Agency€indicated€its€intent€to€revise€the€specificĻtext€in€Section€8.6.1.3.€€Unfortunately,€the€changes€were€not€included€in€the€final€Update€IIIĻversion€of€the€method.ĢĢą  ąThe€intended€text€for€Section€8.6.1.3€is€provided€below,€and€will€be€incorporated€into€theĻnext€revision€of€the€method.ĢĢą8  ąą ` ąņņ8.6.1.3€€The€results€of€the€calibration€blank€are€to€be€less€than€three€timesŠ š@  Šthe€laboratory's€IDL€for€each€analyte.€€If€this€is€not€the€case,€the€reason€for€theĻout-of-control€condition€must€be€found€and€corrected,€and€the€affected€samplesĻmust€be€reanalyzed.€€If€the€laboratory€consistently€has€concentrations€greaterĻthan€three€times€the€IDL,€then€the€IDL€may€be€indicative€of€an€estimated€IDL€andĻshould€be€re-evaluated.€€If€the€blank€is€less€than€1/10th€of€the€concentration€of€theĻlowest€sample€of€the€batch,€the€analysis€need€not€be€terminated.ó󊐹Š Š  ŠĢĢņ ņŌ  ŌMethod€8000B€„€Determinative€Chromatographic€Separationsó óŠ `° ŠĢņ ņItem€1€„€Other€Measures€of€Goodness€of€Fit€for€Non„Linear€Calibrationsó óŠ @ ŠĢą  ąA€major€aspect€of€the€revisions€to€Method€8000B€for€Update€III€was€to€address€the€use€ofĻcalibration€models€other€than€the€traditional€"linear,€through€the€origin"€approach€that€hasĻhistorically€been€specified€in€EPA€methods.€€Based€on€comments€received€during€the€proposal€ofĻUpdate€III,€the€Agency€included€a€wide€array€of€possible€calibration€options€and€used€severalĻmeasures€of€the€"goodness€of€fit"€of€the€calibration€relationship€to€the€actual€calibration€data.€€AtĻleast€one€of€those€approaches€employed€the€use€of€multiple€analyses€of€each€calibration€standard,Ļin€order€to€develop€a€statistically„based€calibration€model.€€Specifically,€that€model€used€theĻinverse€of€the€variance€(or€the€standard€deviation€squared)€as€a€weighting€factor€for€a€weightedĻleast€squares€regression.ĢĢą  ąBased€on€comments€received€subsequent€to€the€promulgation€of€Update€III,€EPA€hasĻreviewed€the€use€of€other€specific€weighting€factors€for€a€least€squares€regression€model.€€UsingĻstatistical€methods,€it€can€be€shown€that€the€variance€of€replicate€measurements€ņņwithin€theŠ `'°"% Šcalibration€rangeóó€of€an€instrument€is€approximately€proportional€to€the€concentration€at€eachŠ P( #& Špoint€at€which€the€variance€can€be€measured.€€As€a€result,€it€is€statistically€possible€to€use€eitherĻthe€inverse€of€the€concentration€or€the€inverse€of€the€concentration€squared€as€a€weighting€factor.€ĻThis€approach€has€the€advantage€of€not€requiring€multiple€analyses€of€each€calibration€standardĻand€is€also€supported€by€many€laboratory€data€systems.ĢĢą  ąTherefore,€the€Agency€recommends€that€when€a€weighted€least€squares€regression€isĻperformed€on€the€results€of€single€injections€of€a€multiple€point€calibration€(e.g.,€not€replicateŠ ą.0*- Šinjections)€that€the€term€1/concentration€or€1/(concentration)ņņ2óó€be€used€as€a€weighting€factor.€€TheŠ ° ŠAgency€further€recommends€the€use€of€this€form€of€weighted€regression€over€the€use€of€anĻunweighted€regression.ĢĢą  ąFurther,€the€Agency€recognizes€that€the€relative€standard€error€(RSE)€is€a€useful€measureĻof€the€goodness€of€fit€of€a€calibration€model€that€the€Agency€had€not€previously€considered.€€TheĻRSE€is€useful€for€both€linear€regression€models€as€well€as€non„linear€models,€as€it€considers€theĻerror€at€each€point€in€the€calibration€model€as€a€function€of€the€concentration€of€that€standard.€ĻThe€RSE€is€calculated€as€shown€below:Ģßs€0=-)b| š,ä ` X@E± ˆddé ĄM H A sßā °±°±°(#°(#ā°ā °±°±°±°±ā°ā °±°±°±°±ā°ā °±°±°±°±ā°ā °±°±°±°±ā°ā °±°±°±°±ā°ā °±°±°±°±ā°ā °(#°(#°±°±āŌ  Ōwhere:ĢĢÓ0°,X°'ø —X°,X›X0Óną ' ą=ą0  ąNumber€of€calibration€pointsŠą(#(# Špą ' ą=ą0  ąNumber€of€parameters€in€the€model€(1€for€linear€through€the€origin,€2€for€linear€notŠ €Š Šthrough€the€origin,€€3€for€quadratic,€etc.)Š (#(# ŠCņņióóą ' ą=ą0  ąTrue€concentration€of€the€standard€at€level€iŠ`°(#(# ŠPCņņióóą ' ą=ą0  ąPredicted€concentration€at€level€i,€using€the€calibration€model€chosenŠP (#(# ŠĢĢą ' ąÓ0 °,X„X°,X°'ø —X0ÓUsing€the€RSE€as€a€metric€has€the€added€advantage€of€allowing€the€same€numerical€standardĻto€be€applied€to€the€calibration€model,€regardless€of€the€form€of€the€model.€€Thus,€if€a€methodĻstates€that€the€RSD€should€be€šš€20%€for€the€traditional€linear€model€through€the€origin,€then€theŠ P ŠRSE€acceptance€limit€can€remain€20%€as€well.€€Similarly,€if€a€method€provides€an€RSDĻacceptance€limit€of€15%,€then€that€same€figure€can€be€used€as€the€acceptance€limit€for€the€RSE.ĢĢą  ąThe€Agency€also€recognizes€that€there€is€a€typographical€error€in€one€of€the€equations€inĻSection€7.5.2,€which€addresses€the€use€of€the€weighted€least€squares€regression.€€The€weightingĻfactor€should€not€appear€in€that€equation.€€The€text€and€the€third€equation€on€page€21€should€readĻas€follows:ĢĢą0  ąą ` ąņņWhen€a€weighted€linear€least€squares€regression€is€employed,€the€regressionŠ p&Ą!$ Šequation€becomes:óóŠ`'°"%(#(# Šßi€03#`< p<y `€EO Ą(<yŸ=ž’‡ P(Ģ±ißā °‡ °‡ °(#°(#āĢĢĢā °(#°(#°‡ °‡ āŌ  Ōņ ņItem€2€„€Reporting€of€Results€from€Dual„Column€Analysesó óŠ  +p&) ŠĢą  ąSection€7.10.4€of€Method€8000B€addresses€the€reporting€of€results€when€analyses€areĻperformed€on€two€chromatographic€columns€of€dissimilar€phase.€€The€Agency's€intent€withĻregard€to€this€issue€was€to€provide€guidance€to€the€analyst€in€those€instances€when€an€analysisŠ ą.0*- Šnecessarily€produces€two€numerical€results.€€The€Agency€is€aware€that€this€section€has€led€toĻsubstantial€confusion€and€wishes€to€point€out€that,€as€written,€the€discussion€ņņonly€óóapplies€to€thoseŠ  š Šinstances€in€which€the€results€of€the€two€analyses€differ€by€more€than€40%€ņņandóó€when€noŠ ą Šinterferences€or€chromatographic€anomalies€are€evident.€€The€Agency's€intent€was€to€prompt€theĻanalyst€to€identify€those€instances€in€which€the€difference€was€relatively€large€(e.g.,€>40%€RPD)Ļand€then€determine€if€corrective€action€was€necessary.ĢĢą  ąWhile€the€Agency€agrees€that,€in€many€instances,€there€may€be€positive€interferences€inĻgas€chromatographic€analysis€in€particular€that€will€lead€to€such€large€differences,€the€AgencyĻbelieves€that€in€those€instances,€if€the€interference€is€apparent€to€the€analyst,€then,€by€definition,Ļthe€reporting€guidance€in€Section€7.10.4€does€not€apply.€€However,€in€other€instances€where€theĻinterference€is€not€apparent,€the€Agency€believes€that€it€is€incumbent€upon€the€analyst€and€theĻregulated€entity€to€employ€an€analytical€method€(or€methods)€that€is€capable€of€determining€theĻanalyte€in€question€without€differences€of€this€magnitude.€€The€Agency€does€not€believe€that€it€isĻreasonable€to€ņņalwaysóó€accept€the€lower€of€two€values€as€the€"correct"€one.€€The€Agency€is€ņņnotóóŠ Š  Šsuggesting€that€the€analyst€search€for€a€method€that€produces€a€result€predetermined€by€theĻregulated€entity.€€Rather,€the€Agency€recognizes€that€some€analytes€are€more€difficult€toĻdetermine€in€some€matrices€and€that€remedying€the€situation€may€require€changes€in€theĻextraction€procedures€or€conditions,€the€use€of€specific€cleanup€techniques,€or€the€use€of€anotherĻdeterminative€method.ĢĢą  ąThe€Agency€recognizes€that€there€are€instances€in€which€an€approach€other€than€thatĻdescribed€in€Section€7.10.4€may€be€appropriate.€€There€are€also€reporting€considerations€that€mayĻapply€even€when€the€numerical€differences€are€not€so€large.€€Therefore,€the€Agency€recommendsĻthat€data€reporting€in€general,€and€reporting€of€dual„column€results€in€particular,€be€specificallyĻaddressed€in€a€sampling€and€analysis€plan€that€is€reviewed€and€approved€by€the€relevantĻregulatory€authority.€€However,€in€the€absence€of€such€a€plan,€the€Agency€believes,€as€stated€inĻSection€7.10.4,€that€an€approach€that€is€conservative€relative€to€environmental€protection€is€toĻreport€the€higher€of€the€two€values€when€the€relative€percent€difference€is€greater€than€40%€ņņandóóŠ š@ Šno€interferences€or€chromatographic€anomalies€are€evident.€€ĢĢą  ąThe€Agency€also€notes€that€Section€8.2.3€of€Method€8000B€provides€a€short€list€ofĻpotential€chromatographic€problems€to€be€considered€in€evaluating€sample€results,€includingĻthose€with€large€numerical€differences.€€In€addition€to€those€listed,€the€Agency€recognizes€thatĻother€problems€will€certainly€occur.€€Examples€include:€€one€peak€barely€discernible€above€theĻinstrumental€noise€and€a€large€Gaussian€peak€on€the€other€column€that€is€most€likely€just€anĻinterference.€ĢĢņ ņŌ  ŌItem€3€„€Instrument„Specific€QC€Limitsó óŠ P( #& ŠĢą  ąIn€responses€to€comments€on€the€proposal€of€Method€8000B€in€Update€III,€the€AgencyĻagreed€with€the€commenters€that€the€reference€to€"instrument„specific"€QC€limits€in€Section€8.1Ļof€the€method€was€not€necessary€and€the€Agency€agreed€to€remove€the€sentence€that€encouragedĻthe€development€of€such€limits.€€An€editorial€error€occurred€in€the€final€version€of€Method€8000BĻā āthat€retained€the€instrument„specific€QC€limit€language€and€unintentionally€deleted€otherŠ š-@), Šimportant€language.€€Therefore,€the€Agency€is€clarifying€its€original€intent,€developed€in€responseĻto€the€Update€III€comments.€€Section€8.1€of€Method€8000B€should€read€as€follows:Ģā āĢņņą  ą8.1ą ` ąRefer€to€Chapter€One€for€specific€quality€control€procedures.€€Each€laboratoryŠ €Š Šusing€SW„846€methods€should€maintain€a€formal€quality€assurance€program.€€The€developmentĻof€in„house€QC€limits€for€each€method€is€encouraged,€as€described€in€Sec.€8.7.€€In€general,€theĻfollowing€QC€requirements€pertain€to€all€the€determinative€methods€listed€in€Sec.€1.1€unlessĻsuperseded€by€specific€requirements€provided€in€each€determinative€method.ĢóóĢŌ  Ōņ ņItem€4€„€The€Appropriate€Use€of€Matrix€Spike€Resultsó óŠ  p  ŠĢą  ąSection€8.5€of€Method€8000B€recommends€that€a€matrix€spike€(MS)€and€matrix€spikeĻduplicate€(MSD)€pair€be€analyzed€with€each€batch€of€up€to€20€samples.€€The€MS/MSD€results€areĻan€important€measure€of€the€performance€of€the€method€relative€to€the€specific€sample€matrix€ofĻinterest.€€The€Agency€believes€that€such€a€demonstration€is€an€important€aspect€of€an€overallĻquality€assurance€program,€and€is€particularly€important€for€the€RCRA€program,€where€a€wideĻrange€of€different€matrices€are€subject€to€regulation.ĢĢą  ąThe€1€per€20€(5%)€frequency€is€a€default€value€that€has€been€used€in€many€EPA€programsĻfor€many€years.€€The€Agency€believes€that€a€default€frequency€is€needed€to€preclude€someĻlaboratories€from€deciding€that€no€MS/MSD€results€need€to€be€provided€at€all.€€However,€theĻAgency€also€recognizes€that€other€frequencies€may€be€appropriate€under€other€circumstances.€ĻFor€example,€in€the€case€of€a€long„term€monitoring€project€involving€a€small€number€of€analysesĻof€a€sample€matrix€that€does€not€change,€it€should€not€be€necessary€to€prove€that€the€methodĻapplies€to€the€matrix€each€time€that€samples€are€collected€and€analyzed.ĢĢą  ąTo€that€end,€the€Agency€recommends€that,€if€another€frequency€for€the€MS/MSD€analysesĻis€chosen,€that€it€be€clearly€documented€in€a€sampling€and€analysis€plan€that€is€reviewed€andĻapproved€by€the€relevant€regulatory€authority.€€ĢĢą  ąThe€Agency€also€is€aware€that€some€clients€do€not€provide€laboratories€with€additionalĻvolume€of€sample€from€which€to€prepare€the€MS/MSD€aliquots.€€In€some€cases,€the€problem€isĻan€oversight€on€the€part€of€the€samplers.€€It€may€also€be€due€to€difficulties€in€obtaining€sufficientĻvolume,€such€as€from€a€poorly€producing€groundwater€well.€€However,€in€other€instances,€theĻclient€simply€may€be€assuming€that€the€laboratory€will€prepare€the€MS/MSD€from€anotherĻsample€prepared€at€the€same€time.€€Unfortunately,€this€latter€situation€can€result€in€the€provisionĻof€MS/MSD€results€from€a€matrix€that€is€only€marginally€related€to€the€samples€in€question.ĢĢą  ąDue€to€the€importance€of€the€relationship€between€the€matrices€of€the€MS/MSD€and€theĻfield€samples,€the€Agency€stresses€that€an€MS/MSD€pair€(or€a€spiked€sample€and€a€duplicateĻsample)€should€be€prepared€from€additional€volumes€of€the€material€collected€from€the€site€inĻquestion.€Each€MS/MSD€will€require€that€additional€sample€volume€from€the€site€be€provided€toĻthe€laboratory€by€the€field€sampling€personnel.€€The€Agency€further€recommends€that€data€usersĻshould€be€routinely€provided€with€the€MS/MSD€results€from€ņņonlyóó€those€QC€samples€associatedŠ -P(+ Šwith€the€field€samples€from€the€same€site.ĢŠ ą.0*- Šą  ąFinally,€the€Agency€is€aware€of€some€persistent€misunderstandings€about€the€intendedĻrole€of€the€MS/MSD€analyses.€€The€Agency€stresses€that€the€ņņprimary€óópurpose€of€these€QCŠ  š Šanalyses€is€to€establish€the€applicability€of€the€overall€analytical€approach€(e.g.,€preparative,Ļcleanup,€and€determinative€methods)€to€the€specific€sample€matrix€from€the€site€of€interest.€ĻUnfortunately,€some€may€believe€that€the€MS/MSD€results€can€and€should€ņņroutinelyóó€be€used€toŠ pĄ Ševaluate€performance€of€an€individual€laboratory.€€The€Agency€stresses€that€such€use€is€ņņnotóó€theŠ ` ° ŠAgencyššs€intent€in€specifying€that€MS/MSD€analyses€be€performed€at€a€5%€frequency.€€TheĻAgency€specifically€included€a€discussion€of€the€use€of€a€laboratory€control€sample€(LCS)€inĻMethod€8000B,€as€one€tool€that€should€be€used€to€evaluate€laboratory€performance.€€SectionĻ8.5.5€of€Method€8000B€addresses€the€use€of€LCS€results€in€conjunction€with€MS/MSD€results€toĻseparate€issues€of€laboratory€performance€and€"matrix€effects."€€ĢĢą  ąThe€Agency€does€believe€that€consistent€ņņtrendsóó€in€MS/MSD€results€can€be€somewhatŠ š@  Šuseful€in€evaluating€laboratory€performance,€as€are€trends€in€surrogate€recoveries,€LCSĻrecoveries,€and€other€QC€data.€€However,€the€appropriate€use€of€a€ņņsingleóó€set€of€MS/MSD€resultsŠ Š  Šis€to€evaluate€ņņmethodóó€performance€in€the€matrix€of€interest,€not€ņņlaboratoryóó€performance.Š Ą ŠĢĢņ ņMethod€8082€„€Polychlorinated€Biphenyls€(PCBs)€by€Gas€Chromatographyó óŠ ą ŠĢņ ņItem€1€„€Frequency€of€the€Initial€Demonstration€of€Proficiencyó óŠ pĄ ŠĢą  ąSection€8.3.€of€Method€8082€addresses€the€initial€demonstration€of€proficiency.€€This€testĻis€to€be€conducted€by€each€laboratory€prior€to€the€analysis€of€samples,€and€serves€to€demonstrateĻthe€laboratory's€ability€to€perform€the€method€is€a€clean€matrix.€€Section€8.3.1.1€states€that€theĻQC€reference€sample€be€analyzed€at€a€frequency€of€once€for€each€group€of€up€to€20€field€samples.€ĻThis€section€is€clearly€in€error,€since€performance€of€the€initial€demonstration€is€not€tied€to€aĻspecific€group€of€field€samples.€€The€specifications€for€the€frequency€of€the€initial€demonstrationĻare€correctly€provided€in€Section€8.3.1.€€The€Agency€regrets€this€editorial€error€and€requests€thatĻanalysts€ignore€this€otherwise€illogical€discussion€of€frequency,€which€has€been€corrected€in€theĻDraft€Update€IVA€revision€of€the€method.ĢĢą  ąThe€Agency€further€notes€that€the€discussions€of€calibration€verification€in€Section€8.3.2Ļand€8.3.3€of€Method€8082€should€not€be€in€Section€8.3,€but€rather€should€appear€as€part€ofĻSection€8.2,€since€these€considerations€apply€to€the€quality€control€procedures€necessary€toĻevaluate€GC€performance€that€are€mentioned€in€Section€8.2.€€The€Agency€has€corrected€thisĻeditorial€error€in€the€next€revision€of€the€method€and€advises€laboratories€to€consider€theseĻaspects€of€quality€control€in€conjunction€with€all€GC€analyses,€not€just€the€initial€demonstrationĻof€proficiency€described€in€Section€8.3.ĢĢņ ņItem€2€„€QC€Limits€that€Conflict€with€Method€8000ó óŠ 0*€%( ŠĢą  ąSection€8.3.1.2€of€Method€8082€provides€quality€control€acceptance€criteria€of€80„120%Ļrecovery€for€the€initial€demonstration€of€proficiency.€€In€reviewing€the€method,€the€AgencyĻrecognizes€that€these€limits€conflict€with€the€more€general€guidance€provided€in€Method€8000Ļregarding€the€initial€demonstration.€€As€specifically€described€in€Method€8000,€limits€of€70„Š ą.0*- Š130%€recovery€should€be€used€by€the€laboratory€as€ņņinterim€guidanceóó€while€the€laboratoryŠ ° Šcollects€enough€data€to€generate€in„house€control€limits€for€the€initial€demonstration€ofĻproficiency.€€Once€such€limits€have€been€generated,€the€70„130%€guidance€limits€are€no€longerĻapplied.ĢĢą  ąThe€Agency€recommends€that€analysts€use€the€approach€described€in€Method€8000€inĻplace€of€the€discussion€of€Section€8.3.1.2€in€Method€8082,€and€has€addressed€this€issue€in€theĻnext€revision€of€the€method.Ģ