’WPC• ¢ŠüŗHv’¬4;łČ4øū©üńWŽzs‚n‹ČYĄė~';D$ųµq]ŲÉ ¾÷nlŗ5§€)Ż^%¾”čŸg“„/ł®ĆXK®r9Ē)7ÜĒüóˆÓ)%{ņ^åæ‚¾£„j…śÄܬŸ9»ø¢éø÷/®½&r•ś-„ģŁ4tä^żqōéiŪ {‡ń“%F5Y+@4©xUf9w†Ÿł>#³F=Ń$‹ÖBŠ€ˆµ+Œb€]„\(6“¼Lū3l£—›yl'?kk:Čq\CRł»Ž&¹Bx7k-õ½^†1ˆ¤Ą¦}Ć_q‹ØP„U‚6Ro‡ų{;,N݉—ģ«Rƒ:¦Ap‹* Se5Ą_»n Ł²ø`°ŠD:OĪĀ9cϾOnhBšļEl<ÜF|¤š8 Ź»R*-h…'*†¤ %į­E6ŗó]!õSĶDŸ<˜ŖJ¤Ąń+:~»ųJQ¹F6?Å}Rv/A{ySäĖ- Üȁ|6ŗčĢäĒ ŪTa`·sąˆhŖį0nMugĀ‘{Œ“RÅl˜?ÕÕčb…;£h™‡—_Mk#ņaœ=źIHO‹§9•s3y(æQ Jh€’ PN\"_!Y€7jUNĢ % 0@ U @` UN  .ī #Į ^ Ż wé 4ķ  0c 1us 72č 0w 0Š‘ 0  0“» 0Ēo 0Ū6 0ļ 0D 1‰D 72ĶĘ’ĘÅʋĘQĘfŻaßóNõ m÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷÷ B  B*+ B/*U Be œ 0ļ¦(ÖĆ9 Z‹6Times New Roman RegularX&ō÷$”Ō€X9X X XŌŌ€X9XXX9ŌŌŌÓ*°‚XÜ•,Š ŽX°œX*ÓÖ€’’ÖŌ€X9X X XŌŌ€X9XXX9ŌŌŌÓ*°‚XÜ•,Š ŽX°œX*ÓÖ€’’Ö(ÖĆ9 Z‹(Times New Roman (ČhH  Z ‹6Times New Roman Regular $Ż ƒiY‘)ŻŌ€X9¬XXXŌŌ€X9¬XXX9¬ŌŌŌÓ*°‚XÜ•,Š ŽX°œX*ÓŻ  ŻÓ  ÓŌ.2ƒh"heast_ug_0401.wpd2Ōheast_ug_0401.wpdŌ/  ŌŠ ° ŠŌ"US ś/ś/śŌ1/26/01˜Lexmark Optra R +,ü,,,,,ü0\…F1s !ˆF0ing ø<§3|x(;3£$““Ō2#ŌŚ  Ś0Ś  Ś.Ō3  Ōą0  ą3#37=CIQYag­­1.a.i.(1)(a)(i)1)a) i)(Oé;$µµą0  ąŌ2#ŌŚ  ŚaŚ  Ś.Ō3  Ōą0` (#(#ą(b·¤$¶¶ą0  ąą0` (#(#ąŌ2#ŌŚ  ŚŚ  Ś.Ō3  Ōą0ø ` (#` (#ą(xir$··ą0  ąą0` (#(#ąą0ø ` (#` (#ąŌ2#Ō(Ś  Ś0Ś  Ś)Ō3  Ōą0ø (#ø (#ą(ŒÜ$øøą0  ąą0` (#(#ąą0ø ` (#` (#ąą0ø (#ø (#ąŌ2#Ō(Ś  ŚaŚ  Ś)Ō3  Ōą0h(#(#ą(ŸF$¹¹ą0  ąą0` (#(#ąą0ø ` (#` (#ąą0ø (#ø (#ąą0h(#(#ąŌ2#Ō(Ś  ŚŚ  Ś)Ō3  Ōą0Ąh(#h(#ą(³Ąō$ŗŗą0  ąą0` (#(#ąą0ø ` (#` (#ąą0ø (#ø (#ąą0h(#(#ąą0Ąh(#h(#ąŌ2#ŌŚ  Ś0Ś  Ś)Ō3  Ōą0Ą(#Ą(#ą(ǵ{$»»ą0  ąą0` (#(#ąą0ø ` (#` (#ąą0ø (#ø (#ąą0h(#(#ąą0Ąh(#h(#ąą0Ą(#Ą(#ąŌ2#ŌŚ  ŚaŚ  Ś)Ō3  Ōą0p(#(#ą(F$ļļą0  ąą0` (#(#ąą0ø ` (#` (#ąą0ø (#ø (#ąą0h(#(#ąą0Ąh(#h(#ąą0Ą(#Ą(#ąą0p(#(#ąŌ2#ŌŁ ŁŚ  ŚŚ  ŚŁ Ł)Ō3  Ōą0Čp(#p(#ąŁ Ł xEģGaeimquy}Bullet ListBullets ListLevel 1Level 2Level 3Level 4Level 5‚Level 1Level 2Level 3Level 4Level 5ƒLevel 1Level 2Level 3Level 4Level 5„Level 1Level 2Level 3Level 4Level 5…Level 1Level 2Level 3Level 4Level 5ąTABLE A ’U‹’ĄĄĄ d&õ’P d d&’’0 d dö’  d (Ē3Y‘$©©Ż‚ō÷!ŻŌ€X9¬XXXŌŌ€X9¬XXX9¬ŌŌŌÓ*°‚XÜ•,Š ŽX°œX*ÓÖ€’’ÖŻ  ŻŻ‚ō÷ŻŻ  ŻŌ_ŌŻ‚ō÷!ŻŌ€X9¬XXXŌŌ€X9¬XXX9¬ŌŌŌÓ*°‚XÜ•,Š ŽX°œX*ÓÖ€’’ÖŻ  ŻŻ‚ō÷ŻŻ  ŻŻƒō÷ø݌̌Ō€X9¬XXX9¬ŌŌ€X9¬XXX9¬ŌŌŌÓ* °œX°‚XÜ•,Š ŽX*ÓÖ€ŲÖŻ  ŻÓ  ÓŌ‡ ŠYXX9¬Ōņ ņUSER'S€GUIDE:€RADIONUCLIDE€CARCINOGENICITYó óŌ#†X9¬X ŠY”#ŌŠ œģ ŠĢÓˆÓĢņ ņIntroductionó óŠ ®ž ŠĢ€€€€€€€€€€€€€€EPA€classifies€all€radionuclides€as€Group€A€carcinogens.€The€Radionuclide€Table€onŠ † Ö Šthis€website,€formerly€HEAST€Table€4,€lists€ingestion,€inhalation€and€external€exposure€cancerŠ r Ā Šslope€factors€(risk€coefficients€for€total€cancer€morbidity)€for€radionuclides€in€conventional€unitsŠ ^ ® Šof€picocuries€(pCi).(7)€Ingestion€and€inhalation€slope€factors€are€central€estimates€in€a€linearŠ J š  Šmodel€of€the€age-averaged,€lifetime€attributable€radiation€cancer€incidence€(fatal€and€nonfatalŠ 6†  Šcancer)€risk€per€unit€of€activity€inhaled€or€ingested,€expressed€as€risk/pCi.€External€exposureŠ "r  Šslope€factors€are€central€estimates€of€lifetime€attributable€radiation€cancer€incidence€risk€for€eachŠ ^  Šyear€of€exposure€to€external€radiation€from€photon-emitting€radionuclides€distributed€uniformlyŠ śJ  Šin€a€thick€layer€of€soil,€and€are€expressed€as€risk/yr€per€pCi/gram€soil.€When€combined€withŠ ę6  Šsite-specific€media€concentration€data€and€appropriate€exposure€assumptions(8),€slope€factors€canŠ Ņ" Šbe€used€to€estimate€lifetime€cancer€risks€to€members€of€the€general€population€due€toŠ ¾ Šradionuclide€exposures.Š Ŗś ŠĢņ ņIntended€Users€and€Applicationsó óŠ ‚Ņ ŠĢą  ąHEAST€users€include€individuals€from€the€EPA,€other€Federal€agencies,€States€andŠ ZŖ Šcontractors€who€are€responsible€for€the€identification,€characterization€and€remediation€of€sitesŠ F– Šcontaminated€with€radioactive€materials.€Radionuclide€slope€factors€are€calculated€by€EPA'sŠ 2‚ ŠOffice€of€Radiation€and€Indoor€Air€(ORIA)€to€assist€HEAST€users€with€risk-related€evaluationsŠ n Šand€decision-making€at€various€stages€of€the€remediation€process.€During€site€assessment,€forŠ  Z Šexample,€slope€factors€are€used€in€EPA's€Hazard€Ranking€System€(HRS)€to€assign€toxicity€factorŠ öF Švalues€to€radionuclides€to€calculate€site€scores.€During€the€remedial€investigation€and€feasibilityŠ ā2 Šstudy€(RI/FS),€slope€factors€are€used€to€determine€baseline€site€risk,€to€develop€preliminaryŠ Ī Šremediation€goals,€and€to€evaluate€cleanup€alternatives.€For€further€examples€on€the€applicationŠ ŗ  Šof€radionuclide€slope€factors€in€risk€evaluations,€users€are€referred€to€the€following€EPAŠ ¦ ö Šdocuments:Š ’!ā ŠĢӁ€  (Eģy3 ÓŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£× ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻHazard€Ranking€System€(HRS),€Federal€Register€(55€FR€515320),€December€1990.€Żƒ 3£×  ݌Šj#ŗ!(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£Ū ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻRisk€Assessment€Guidance€for€Superfund;€Volume€I€-€Human€Health€Evaluation€ManualŠ B%’ # Š(RAGS/HHEM),€Part€A,€Baseline€Risk€Assessment€(EPA/540/1-89/002).Żƒ 3£Ū ݌Š.&~!$(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£9ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻRAGS/HHEM€Part€B,€Development€of€Risk-Based€Preliminary€Remediation€GoalsŠ (V#& ŠOSWER€Directive€9285.7-01B).€[NTIS€order€number:€PB€92-963333.]Żƒ 3£9f݌Šņ(B$'(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻRAGS/HHEM€Part€C,€Risk€Evaluation€of€Remedial€Alternatives€(OSWER€DirectiveŠ Ź*&) Š9285.7-01C).€[NTIS€order€number:€PB€92-963334.]Żƒ 3£ŗ݌ж+'*(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£ÓŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻŌ‡X9¬XXX9¬ŌSoil€Screening€Guidance€for€Radionuclides:€User's€Guide,€October€2000.€€(OSWERŠ Ž-Ž(, ŠDirective€9355.4-16AŌ#†X9¬XXX9¬F#Ō)€ņ ņ(note:€The€models,€equations,€and€assumptions€presented€inŠ ° Šthe€Soil€Screening€Guidance€for€Radionuclides€supercede€those€described€in€RAGSŠ  š ŠHHEM,€Part€B,€for€residential€soils.)ó óŻƒ 3£Ó݌ŠŒÜ(#(# ŠŒŻ  ŻĢą  ąCopies€of€RAGS/HHEM€Parts€A,€B€and€C€are€available€to€the€public€from€the€NationalŠ d“ ŠTechnical€Information€Service€(NTIS)€at€(703)€487-4650.€Copies€are€available€to€EPA€staff€byŠ P   Šcalling€the€Superfund€Documents€Center€at€(703)€603-8917.€€The€š šŌ‡X9¬XXX9¬ŌSoil€Screening€Guidance€forŠ < Œ ŠRadionuclides:€User's€GuideŌ#†X9¬XXX9¬J#Ōšš,€is€available€atŠ ( x ŠŌ‡X9¬XXX9¬Ōš šhttp://www.epa.gov/superfund/resources/radiation/radssg.htm#userŌ#†X9¬XXX9¬#Ōšš.Š  d ŠĢņ ņRadiation€Effectsó óŠ ģ <  ŠĢą  ąIonizing€radiation€has€been€shown€to€be€a€carcinogen,€a€mutagen,€and€a€teratogen.Š Ä  ŠRadiation€can€induce€cancers€in€nearly€any€tissue€or€organ€in€both€humans€and€animals,€and€theŠ °  Šprobability€of€cancer€induction€increases€with€increasing€radiation€dose.€Cancer€induction€is€aŠ œģ  Šdelayed€response€that€has€been€documented€extensively€in€epidemiological€studies€of€JapaneseŠ ˆŲ  Šatomic€bomb€survivors,€underground€uranium€miners,€radium€dial€painters,€and€patients€subjectŠ tÄ Što€a€variety€of€radiation€treatments.€Laboratory€animal€research€and€mammalian€tissue€cultureŠ `° Šstudies€have€provided€additional,€collaborative€data.Š Lœ ŠĢą  ąMutagenic€effects€of€radiation€have€been€demonstrated€primarily€in€animal€and€tissueŠ $t Šculture€studies;€limited€data€from€studies€of€A-bomb€survivors€indicate€that€humans€may€be€asŠ ` Šsensitive€or€less€sensitive€than€animals€to€radiogenic€mutagenicity€(heritable€genetic€mutations).Š üL ŠData€are€also€available€from€both€human€and€animal€studies€on€the€teratogenic€effects€ofŠ č8 Šradiation.€These€data€show€that€the€fetus€is€most€sensitive€to€radiation€injury€during€the€earlyŠ Ō$ Šstages€of€organ€development€(between€8€and€15€weeks€for€the€human€fetus).€ResultantŠ Ą Šradiation-induced€malformations€depend€on€which€cells€are€most€actively€differentiating€at€theŠ ¬ü Štime€of€exposure.Š ˜č ŠĢą  ąEPA€classifies€all€radionuclides€as€Group€A€carcinogens,€based€on€their€property€ofŠ pĄ Šemitting€ionizing€radiation€and€on€the€extensive€weight€of€evidence€provided€by€epidemiologicalŠ \ ¬ Šstudies€of€radiogenic€cancers€in€humans.€At€Superfund€radiation€sites,€EPA€generally€evaluatesŠ H!˜ Špotential€human€health€risks€based€on€the€radiotoxicity,€i.e.,€adverse€health€effects€caused€byŠ 4"„  Šionizing€radiation,€rather€than€on€the€chemical€toxicity,€of€each€radionuclide€present€(anŠ  #p! Šexception€is€uranium,€where€both€radiotoxicity€and€chemical€toxicity€are€normally€evaluated).Š  $\" ŠThese€evaluations€consider€the€carcinogenic€effects€of€radionuclides€only.€In€most€cases,€cancerŠ ų$H # Šrisks€are€limiting,€exceeding€both€mutagenic€and€teratogenic€risks.Š ä%4!$ ŠĢņ ņDerivation€of€Radionuclide€Slope€Factorsó óŠ ¼' #& ŠĢą  ąEPA's€Office€of€Radiation€and€Indoor€Air€(ORIA)€calculates€radionuclide€slope€factorŠ ”)ä$( Švalues€using€health€effects€data€and€dose€and€risk€models€from€a€number€of€national€andŠ €*Š%) Šinternational€scientific€advisory€commissions€and€organizations,€including€the€National€AcademyŠ l+¼&* Šof€Sciences€(NAS),€the€National€Council€on€Radiation€Protection€and€Measurements€(NCRP),Š X,Ø'+ Šthe€United€Nations€Scientific€Committee€on€the€Effects€of€Atomic€Radiation€(UNSCEAR),€andŠ D-”(, Šthe€International€Commission€on€Radiological€Protection€(ICRP).€A€detailed€discussion€ofŠ ° ŠORIA's€approach€and€assumptions€is€provided€in€Estimating€Radiogenic€Cancer€Risks€(9).€Š œģ ŠĢą  ąRadionuclide€slope€factors€are€calculated€for€each€radionuclide€individually,€based€on€itsŠ tÄ Šunique€chemical,€metabolic€and€radioactive€properties.€The€calculation€methodology€isŠ `° Šdocumented€in€Federal€Guidance€Report€No.€13€(10).€The€risk€coefficients€derived€in€FederalŠ L œ ŠGuidance€Report€No.€13,€and€used€to€calculate€the€slope€factors€presented€in€the€RadionuclideŠ 8 ˆ ŠTable,€are€based€on€state-of-the-art€methods€and€models€that€take€into€account€the€age-€andŠ $ t Šgender-dependence€of€radionuclide€intake,€metabolism,€dosimetry,€radiogenic€risk,€andŠ  ` Šcompeting€causes€of€death€in€estimating€the€cancer€risk€from€low-level€exposures€toŠ ü L  Šradionuclides€in€the€environment.€The€risk€coefficients€in€Federal€Guidance€Report€No.€13€areŠ č 8  Šestimates€of€the€probability€of€radiogenic€cancer€mortality€(fatal€cancers)€or€morbidity€(fatal€plusŠ Ō$  Šnonfatal€cancers)€per€unit€activity€of€a€given€radionuclide€inhaled€or€ingested,€for€internalŠ Ą  Šexposure,€or€per€unit€time-integrated€activity€concentration€in€air€or€soil,€for€external€exposure.Š ¬ü  ŠThese€risk€coefficients€may€be€interpreted€either€as€the€average€risk€per€unit€exposure€for€personsŠ ˜č  Šexposed€throughout€their€lifetime€to€a€constant€activity€concentration€of€a€radionuclide€in€anŠ „Ō  Šenvironmental€medium€(air€or€soil),€or€as€the€average€risk€per€unit€exposure€for€persons€exposedŠ pĄ Šfor€a€brief€period€to€the€radionuclide€in€an€environmental€medium.€These€risk€coefficients€areŠ \¬ Šbased€on€the€age€and€gender€distributions€and€the€mortality€characteristics€of€the€1989-91€U.S.Š H˜ Šdecennial€life€tables.Š 4„ ŠĢą  ąFederal€Guidance€Report€No.€13€tabulates€risk€coefficient€values€for€both€cancerŠ  \ Šmortality€and€cancer€morbidity€for€six€exposure€pathways:€inhalation,€ingestion€of€tap€water,Š ųH Šingestion€of€foodstuffs,€external€radiation€from€submersion€in€contaminated€air,€externalŠ ä4 Šradiation€from€radionuclides€deposited€on€the€ground€surface,€and€external€exposure€fromŠ Š  Šradionuclides€uniformly€distributed€through€soil.€Additional€risk€coefficients€are€also€providedŠ ¼  Šfor€ingestion€of€milk€for€radioisotopes€of€iodine€only.€Inhalation€risk€coefficients€are€tabulatedŠ Øų Šseparately€for€each€of€the€three€lung€absorption€types€considered€in€the€lung€model€currentlyŠ ”ä Šrecommended€by€the€International€Commission€on€Radiological€Protection€(ICRP),€and,€whereŠ €Š Šappropriate,€for€inhalation€of€radionuclides€in€vapor€or€gaseous€forms.€In€order€to€maintainŠ l¼ Šconsistency€with€risk€assessment€algorithms€presented€in€the€RAGS€documents€referencedŠ X Ø Šabove,€only€four€of€these€exposure€pathways€are€tabulated€in€the€Radionuclide€Table:€inhalation,Š D!” Šwater€ingestion,€food€ingestion,€and€external€exposure€from€radionuclides€distributed€in€soil.€OneŠ 0"€  Šadditional€exposure€pathway€which€is€not€directly€considered€in€Federal€Guidance€Report€No.€13,Š #l! Šincidental€ingestion€of€soil,€is€also€included€in€the€Radionuclide€Table.(11)€In€addition,€the€valuesŠ $X" Šin€the€Radionuclide€Table€have€been€converted€from€the€International€System€(SI)€units€used€inŠ ō$D # ŠFederal€Guidance€Report€No.€13€to€the€conventional€units€of€activity,€again€for€greaterŠ ą%0!$ Šconsistency€with€the€risk€assessment€algorithms€in€current€guidance€(e.g,€RAGS).Š Ģ&"% ŠĢą  ąThe€risk€coefficients€in€Federal€Guidance€Report€No.€13€are€derived€from€the€integrationŠ ¤(ō#' Šof€four€principal€types€of€data:Š )ą$( ŠĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£[3ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻAbsorbed€dose€rates€for€each€tissue€of€interest€(potential€cancer€site)€over€the€remainingŠ h+ø&* Šlifetime€of€an€individual,€resulting€from€an€acute€intake€at€a€given€age€to€the€radionuclideŠ T,¤'+ Šof€interest.€Age-specific€estimates€of€absorbed€dose€rate€are€calculated€for€internalŠ @-(, Šexposures€(inhalation€and€ingestion),€whereas€absorbed€dose€rates€calculated€for€aŠ ° Šreference€adult€male€are€applied€to€all€ages€and€both€genders€for€external€exposures.€Żƒ 3£[3ˆ3݌Šœģ(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£6ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻAge-€and€gender-specific€risk€coefficients,€which€express€the€lifetime€excess€cancerŠ tÄ Šincidence€€risk€per€unit€dose€(e.g.,€expected€cancer€cases€per€unit€absorbed€dose)€forŠ `° Šspecific€cancer€sites€over€the€lifetime€of€the€exposed€population.€Żƒ 3£6F6݌ŠL œ(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£ē7ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻFor€internal€exposures€only,€age-€and€gender-specific€usage€data€for€the€environmentalŠ $ t Šmedium€of€concern€(e.g.,€inhalation€rates€and€ingestion€rates€for€water,€food,€and€milk).€Żƒ 3£ē78݌Š `(#(# ŠŒŻ  ŻĢŻ"‚ 3£"ŻŻ  ŻŻ‚ 3£c9ŻŌ2EģŌššŌ3  Ōą0  ąŻ  ŻVital€statistics€and€mortality€data€for€the€reference€population€(currently€the€1989-1991Š č 8  ŠU.S.€€population),€which€define€the€survival€function€for€an€average€member€of€theŠ Ō$  Špopulation€-€i.e.,€€the€probability€of€survival€and€projected€years€of€life€remaining€at€eachŠ Ą  Šage€in€the€reference€€population,€taking€into€account€competing€risks€(mortality€risksŠ ¬ü  Šunrelated€to€radiation€exposure,€e.g.,€accidents,€illness).€Żƒ 3£c99݌Š˜č (#(# ŠŒŻ  ŻĢą  ąWith€a€few€exceptions,€the€dosimetry€models€for€the€inhalation€and€ingestion€pathwaysŠ pĄ Šare€taken€from€ICRP€Publication€72€(12)€(which€is€a€compilation€of€the€ICRP's€age-dependentŠ \¬ Šdose€coefficients€for€members€of€the€public€from€intake€of€radionuclides),€while€dose€rateŠ H˜ Šestimates€for€external€exposure€pathways€are€taken€from€Federal€Guidance€Report€No.€12€(13),Š 4„ Šwhich€tabulates€dose€coefficients€for€external€exposure€to€radionuclides€in€air,€water,€and€soil.Š  p ŠSince€the€criteria€for€the€list€of€radionuclides€considered€in€these€two€documents€is€not€the€same,Š  \ Šrisk€coefficients€for€some€radionuclides€are€not€provided€for€all€exposure€pathways.Š ųH ŠĢą  ąThe€radionuclide€slope€factors€in€the€Radionuclide€Table€may€be€used€to€estimate€theŠ Š  Šlifetime€cancer€incidence€risk€attributable€to€given€radionuclide€exposure€conditions€for€anŠ ¼  Šaverage€member€of€the€reference€population.€This€estimate€of€excess€risk€is€averaged€over€allŠ Øų Šages€and€both€genders€for€a€population€with€specified€mortality€statistics€(currently€the€U.S.Š ”ä Špopulation€circa€1989-1991).€These€slope€factors€are€appropriate€for€assessing€the€average€riskŠ €Š Šwithin€this€population,€but€are€not€suitable€for€assessing€the€risk€to€a€single€individual€of€aŠ l¼ Šparticular€age€or€gender.€Estimates€of€radiogenic€cancer€risk€are€subject€to€numerous€sources€ofŠ X Ø Šuncertainty,€including€the€biokinetic€and€dosimetric€models,€organ-specific€risk€factors,€mortalityŠ D!” Šand€survival€characteristics€of€the€population,€and€the€extrapolation€of€epidemiological€data€forŠ 0"€  Špopulations€exposed€to€high€radiation€doses€to€much€lower€levels€characteristic€of€environmentalŠ #l! Šexposures.Š $X" ŠĢThe€slope€factors€are€the€average€risk€per€unit€intake€or€exposure€for€an€individual€in€a€stationary€Š ą%0!$ Špopulation€with€vital€statistics€(mortality€rates)€of€the€1990€United€States€population.€(TheŠ Ģ&"% Šexpected€lifetime€for€an€individual€in€this€population€is€about€75€years.)€Consequently,Š ø'#& Šradionuclide€ingestion€and€inhalation€slope€factors€are€not€expressed€as€a€function€of€body€weightŠ ¤(ō#' Šand€time,€and€do€not€require€corrections€for€GI€absorption€or€lung€transfer€efficiencies.Š )ą$( ŠĢĢņņņ ņNOTE:€The€GI€absorption€values€(f1),€ICRP€lung€absorption€types€(F,€M,€S)€and€radioactiveŠ T,¤'+ Šhalf-lives€are€provided€in€the€Radionuclide€Table€for€reference€only€and€should€not€be€used€toŠ <-Œ(, Šcorrect,€modify,€or€in€any€way€adjust€radionuclide€slope€factors€or€intake€assumptions€in€riskŠ ° Šcalculations.€Š ˜č Šó óóóĢĢĢą  ąThe€radionuclide€slope€factors€tabulated€in€the€Radionuclide€Table€are€derived€for€theŠ D ” Šidealized€conditions€of€chronic€radionuclide€intake€or€exposure,€at€a€unit€radionuclideŠ 0 € Šconcentration,€throughout€the€lifetime€of€the€exposed€population.€These€values€can€be€used€inŠ  l Šconjunction€with€site-specific€data€describing€the€concentrations€of€radionuclides€of€concern€inŠ  X Šenvironmental€media€(e.g.,€air,€water,€vegetation,€soil,€and€foodstuffs)€and€with€informationŠ ō D  Šdescribing€the€exposure€conditions€(e.g.,€inhalation€and€ingestion€rates;€exposure€times,Š ą 0  Šfrequencies€and€durations;€etc.)€to€estimate€the€cancer€risk€from€inhaling€contaminated€air,€eatingŠ Ģ  Šcontaminated€food€or€soil,€drinking€contaminated€water,€or€from€external€exposure€toŠ ø  Šcontaminated€ground€surfaces€for€given€site€conditions.€Whether€for€inhalation,€ingestion,€orŠ ¤ō  Šexternal€exposure,€the€lifetime€excess€risk€is€related€to€the€cumulative€intake€or€exposure€to€theŠ ą  Šgiven€radionuclide:Š |Ģ  ŠĢFor€inhalation€and€ingestion,€the€total€radioactivity€(pCi)€inhaled€or€ingested€must€be€known.€Š T¤ ŠĢFor€external€exposure,€the€integral€of€the€product€of€the€soil€concentration€of€each€radionuclide€ofŠ ,| Šinterest€and€the€total€duration€of€exposure€in€the€contaminated€area€(pCi-y€per€gram€of€soil)€mustŠ h Šbe€known,€considering€the€effect€of€shielding€provided€by€buildings€or€other€site€features.€NoteŠ T Šthat€the€soil€concentration€of€each€radionuclide€of€concern€may€vary€over€time€as€a€result€of€theŠ š@ Šradioactive€decay€process€-€i.e.,€concentrations€of€some€radionuclides€may€decrease€over€time€dueŠ Ü, Što€radioactive€decay€whereas€concentrations€of€other€radionuclides€may€increase€due€to€ingrowthŠ Č Šof€radioactive€decay€products.€Also,€the€effect€of€shielding€afforded€by€buildings€during€periodsŠ “ Šof€indoor€occupancy€or€other€site€features€must€be€considered€explicitly,€because€the€slope€factorsŠ  š Šare€derived€for€conditions€of€outdoor€exposure€without€shielding.€Š ŒÜ ŠĢFor€each€radionuclide€and€exposure€pathway,€the€excess€cancer€risk€is€estimated€as€the€product€ofŠ d“ Šthe€slope€factor€and€the€cumulative€intake€or€external€exposure.€The€risks€presented€by€each€Š P   Šradionuclide€(including€radioactive€decay€products)€and€exposure€pathway€in€a€given€exposure€Š @30„„‰>@‰VŠ30Š F<1ģ<-"  >@30 >@ „„FŠBa„137m€(94.6%,€3€min)Š 'ģ<." „„'ŠBa„137Š 6€`#ģ</" „„ˆˆ6Š*Š A€`2'ģ<0"` „„AŠNp„237+DŠ 6,!l¼1"` „„6Š2.1€x€10ņņ6óóŠ 'l¼2" „„'ŠPa„233€(27€d)Š 'l¼3" „„'Šu„233Š 0€`l¼4" „„0Š1.6€x€10ņņ5óóŠ ;€`,!l¼5"` „„;ŠPb„210+DŠ VL!ģ<6"`  6@22„„‰6@‰VŠ22Š F<1ģ<7"  6@22 6@ „„FŠ€Bi-210€(5€d)Š ģ<8 ŠPo-210€(138€d)Š 'Ų(9" „„'Š€Pb-206Š 6€`#ģ<:" „„ˆˆ6Š*Š A€`2'ģ<;"` „„AŠPu„244+DŠ 6,!X!Ø<"` „„6Š8.3€x€10ņņ7óóŠ 'X!Ø=" „„'ŠU-240€(14€h)Š X!Ø> ŠNp-240m€(7.4€Š 'D"”?" „„'ŠPu-240Š R€`?X!Ø@"  @„„ˆˆ‰‰RŠ6.5€x€10ņņ3óóŠ \€`MBX!ØA"  @ ` „„\ŠRa„226+DŠ 6,!Ä#B"` „„6Š1.6€x€10ņņ3óóŠ 'Ä#C" „„'Š€Rn-222€(4€d)Š Ä#D ŠPo-218€(3€min)Š °$ E Š[Pb-214€(99.98%,€27€min)Š œ%ģ F ŠAt-218€(0.02%,€2€s)]Š ˆ&Ų!G ŠBi-214€(99.99%,€20€min)Š t'Ä"H Š[Po-214€(99.98%,€1.64€x€10-4€s)Š `(°#I ŠTl-210€(0.02%,€1€min)]Š 'L)œ$J" „„'ŠPb-210Š P€`=Ä#K"  6@22„„‰6@‰PŠ22Š Z€`K@Ä#L"  6@22 6@` „„ZŠRa„228+DŠ UK!Ģ*&M"`  @6„„‰@‰UŠ6Š E;0Ģ*&N"  @6 @ „„EŠAc„228€(6h)Š 'Ģ*&O" „„'ŠTh„228Š O€`<Ģ*&P"  @2„„‰@‰OŠ2Š Y€`J?Ģ*&Q"  @2 @` „„YŠRu„106+DŠ UK!L,œ'R"`  š?1„„‰š?‰UŠ1Š E;0L,œ'S"  š?1 š? „„EŠRh„106€(30s)Š 'L,œ'T" „„'ŠPd„106Š 6€`#L,œ'U" „„ˆˆ6ŠŌ_Ō*ā āŠ A€`2'L,œ'V"` „„AŠSb„125+DŠ UK! d"`  @3„„‰@‰UŠā ā3Š E;0 d"  @3 @ „„EŠTe„125m€(22.8%,€58d)Š ' d" „„'ŠTe„125Š 6€`# d" „„ˆˆ6Š*Š A€`2' d"` „„AŠSr„90+DŠ VL!€ ä"`  =@29„„‰=@‰VŠ29Š F<1€ ä"  =@29 =@ „„FŠY„90€(64h)Š '€ ä" „„'ŠZr„90Š R€`?€ ä "  @„„ˆˆ‰‰RŠ*Š \€`MB€ ä "  @ ` „„\ŠTh„228+DŠ WM! d "` ffffffž?1.9„„‰ffffffž?‰WŠŌ_Ō1.9ņņóóŌ_ŌŠ G=2 d " ffffffž?1.9 ffffffž? „„GŠ€Ra-224€(4€d)€Š  d  ŠRn-220€(56€s)Š ģ P ŠPo-216€(0.2€s)Š Ų < ŠPb-212€(11€h)Š Ä( ŠBi-212€(61€min)Š ° Š[Po-212€(64.07%,€0.3€Ō_ŌššsŌ_Ō)Š œ ŠTl-208€(35.93%,€3€min)]Š 'ˆģ" „„'ŠPb-208Š 6€`# d" „„ˆˆ6Š*Š A€`2' d"` „„AŠTh„229+DŠ 6,!l "` „„6Š7.3€x€10ņņ3óó€Š 'l " „„'ŠRa-225€(15€d)Š l  ŠAc-225€(10€d)Š ōX  ŠFr-221€(5€min)Š ąD  ŠAt-217€(32€ms)Š Ģ0  ŠBi-213€(46€min)Š ø Š[Po-213€(97.8%,€4€Ō_ŌššsŌ_Ō)Š ¤ ŠTl-209€(2.2%,€2€min)]Š ō ŠPd-209€(3€h)Š '|ą" „„'Š€Bi-209Š R€`?l "  @„„ˆˆ‰‰RŠ*Š \€`MBl !"  @ ` „„\ŠU„235Š 6,!ü`""` „„6Š7.0€x€10ņņ8óóŠ 'ü`#" „„'ŠTh-231€(26€h)Š 'ü`$" „„'ŠPa-231Š 0€`ü`%" „„0Š3.3€x€10ņņ4óóŠ =€^``,!ü`&"` „„=ŠU„238+DŠ =€^`,!|ą'"^`` „„=Š4.5€x€10ņņ9óóŠ =€^`,!|ą("^` „„=ŠTh-234€(24€d)Š |ą) Š[Pa-234m€(99.80%,€1€min)Š hĢ* ŠPa-234€(0.33%,€7€h)]Š =€^`,!Tø+"^` „„=ŠU-234Š ?€^``,!|ą,"^` „„?Š2.4€x€10ņņ5óóŠ1'%|ą-"  ^`` 1ŠĢ(a)€Ō_ŌRadionuclidesŌ_Ō€with€half-lives€greater€than€six€months.€"+D"€designates€principalŠ \ Ą. ŠŌ_ŌradionuclidesŌ_Ō€with€associated€decay€chains.Š H!¬/ ŠĢ(b)€The€chain€of€decay€products€of€a€principal€Ō_ŌradionuclideŌ_Ō€extending€to€(but€not€including)€theŠ  #„1 Šnext€principal€Ō_ŌradionuclideŌ_Ō€or€a€stable€Ō_ŌradionuclideŌ_Ō.€Half-lives€are€given€in€parentheses.€BranchesŠ  $p2 Šare€indicated€by€square€brackets€with€branching€percentages€in€parentheses.Š ų$\3 ŠĢ(c)€The€principal€Ō_ŌradionuclideŌ_Ō€or€stable€nuclide€that€terminates€an€associated€decay€chain.€StableŠ Š&45 Šnuclides€are€indicated€by€an€asterisk€(*)€in€place€of€a€half-life.Š ¼' 6 ŠĢ(d)€A€hyphen€indicates€that€there€are€no€associated€decay€products.Š ”)ų 8 ŠĢÓ  Óņ ņENDNOTESó óŠ l+Š": ŠÓ ŸÓĢ1.€Ō_ŌEckermanŌ_Ō,€Ō_ŌK.F.Ō_Ō,€Ō_ŌLeggettŌ_Ō,€R.W.,€Nelson,€C.B.,€Ō_ŌPuskinŌ_Ō,€Ō_ŌJ.S.Ō_Ō,€and€Richardson,€Ō_ŌA.C.B.Ō_Ō€(1999).Š D-Ø$< ŠŌ_ŌCancer€Risk€Coefficients€for€Environmental€Exposure€to€Radionuclides.€Federal€GuidanceŠ ° ŠReport€No.€13.€EPA€402-R-99-001.Š œģ ŠĢ2.€Soil€ingestion€is€not€considered€as€an€exposure€pathway€in€Federal€Guidance€Report€No.€13.Š tÄ ŠThe€slope€factor€values€reported€in€Table€4€for€soil€ingestion€have€been€computed€using€the€sameŠ `° Šcalculational€methodology€(i.e.,€the€DCAL€computer€code€developed€at€Oak€Ridge€NationalŠ L œ ŠLaboratory),€risk€models,€and€vital€statistics,€in€conjunction€with€the€default€soil€ingestion€rateŠ 8 ˆ Šspecified€in€EPA's€Risk€Assessment€Guidance€for€Superfund€(RAGS),€i.e.,€200€mg/day€fromŠ $ t Šbirth€to€age€6,€and€100€mg/day€for€ages€>6€years.Š  ` ŠĢ3.€Nelson,€C.B.€and€Puskin,€J.S.€(1994).€Estimating€Radiogenic€Cancer€Risk.€EPAŠ č 8  Š402-R-93-076.Š Ō$  ŠĢ4.€International€Commission€on€Radiological€Protection€(ICRP).€(1996).€Human€RespiratoryŠ ¬ü  ŠTract€Model€for€Radiological€Protection.€ICRP€Publication€66.Š ˜č  ŠĢ5.€Eckerman,€K.F.,€and€J.C.€Ryman€(1993).€External€Exposure€to€Radionuclides€In€Air,€Water,Š pĄ Šand€Soil.€Federal€Guidance€Report€No.€12.€EPA€402-R-93-081.Š \¬ ŠĢ6.€EPA€(1997).€OSWER€Directive€9200.4-18,€Establishment€of€Cleanup€Levels€for€CERCLAŠ 4„ ŠSites€with€Radioactive€Contamination.Š  p ŠĢ7.€Slope€factors€are€reported€in€the€Radionuclide€Table€in€the€customary€units€of€picocuries€(1Š ųH ŠpCi€=€10-12€curies€(Ci)€=€3.7x10-2€nuclear€transformations€per€second)€for€consistency€with€theŠ ä4 Šprevious€versions€of€HEAST.€If€required,€slope€factors€in€the€Radionuclide€Table€can€beŠ Š  Šconverted€into€the€International€System€(SI)€units€of€becquerels€(1€Bq€=€1€nuclear€transformationŠ ¼  Šper€second)€by€dividing€each€inhalation,€ingestion,€or€external€exposure€value€by€0.037.€UsersŠ Øų Šcan€calculate€cancer€risks€using€slope€factors€expressed€in€either€customary€units€or€SI€units€withŠ ”ä Šequivalent€results,€provided€that€they€also€use€air,€water€and€soil€concentration€values€in€the€sameŠ €Š Šsystem€of€units.Š l¼ ŠĢ8.€Agency€standardized€default€exposure€scenarios€and€assumptions€for€use€in€baseline€riskŠ D!” Šassessment€are€provided€in€EPA€(1991),€Risk€Assessment€Guidance€for€Superfund,€Vol.€I,Š 0"€  ŠHuman€Health€Evaluation€Manual,€Supplemental€Guidance:€"Standard€Default€ExposureŠ #l! ŠFactors"€(Interim€Final),€Office€of€Emergency€and€Remedial€Response,€OSWER€DirectiveŠ $X" Š9285.6-03.€[NTIS€order€number:€PB€91-921314.]Š ō$D # ŠĢ9.€Nelson,€C.B.€and€Puskin,€J.S.,€(1994).€Estimating€Radiogenic€Cancer€Risk,€EPAŠ Ģ&"% Š402-R-93-076.Š ø'#& ŠĢ10.€Eckerman,€K.F.,€Leggett,€R.W.,€Nelson,€C.B.,€Puskin,€J.S.,€and€Richardson,€A.C.B.€(1999).Š )ą$( Š"Cancer€Risk€Coefficients€for€Environmental€Exposure€to€Radionuclides,"€EPA€402-R-99-001.Š |*Ģ%) ŠĢ11.€Soil€ingestion€is€not€considered€as€an€exposure€pathway€in€Federal€Guidance€Report€No.€13.Š T,¤'+ ŠThe€slope€factor€values€reported€in€the€Radionuclide€Table€for€soil€ingestion€have€been€computedŠ @-(, Šusing€the€same€calculational€methodology€(i.e.,€the€DCAL€computer€code€developed€at€OakŠ ° ŠRidge€National€Laboratory),€risk€models,€and€vital€statistics,€in€conjunction€with€the€default€soilŠ œģ Šingestion€rate€specified€in€EPA's€Risk€Assessment€Guidance€for€Superfund€(RAGS),€i.e.,€200Š ˆŲ Šmg/day€from€birth€to€age€6,€and€100€mg/day€for€ages€>6€years.Š tÄ ŠĢ12.€International€Commission€on€Radiological€Protection,€(1996),€Age-Dependent€Doses€toŠ L œ ŠMembers€of€the€Public€from€Intake€of€Radionuclides,€Part€5,€Compilation€of€Ingestion€andŠ 8 ˆ ŠInhalation€Dose€Coefficients,€ICRP€Publication€72.Š $ t ŠĢ13.€Eckerman,€K.F.€and€J.C.€Ryman,€(1993),€External€Exposure€to€Radionuclides€in€Air,€Water,Š ü L  Šand€Soil,€Federal€Guidance€Report€No.€12,€EPA€402-R-93-081.Š č 8  ŠĢ14.€There€is€one€exception€to€the€assumption€of€secular€equilibrium.€For€the€inhalation€slopeŠ Ą  Šfactor€for€Rn-222+D€reported€in€the€Radionuclide€Table,€ORIA€assumes€a€50%€equilibriumŠ ¬ü  Švalue€for€radon€decay€products€(Po-218,€Pb-214,€Bi-214€and€Po-214)€in€air.€[NOTE:€EPAŠ ˜č  Šexpects€to€publish€revised€risk€estimates€for€inhalation€of€radon€decay€products€in€the€near€future,Š „Ō  Šbased€on€a€revised€equilibrium€assumption€of€40%.]Š pĄ ŠĢ15.€An€exception€is€tritium,€H-3,€where€the€value€for€inhalation€of€tritiated€water€vapor€isŠ H˜ Šreported€in€the€Radionuclide€Table,€even€though€this€value€is€less€than€that€from€inhalation€ofŠ 4„ ŠH-3€in€particulate€form€or€organic€gases,€because€this€form€is€expected€to€be€most€common€in€theŠ  p Šenvironment.Š  \ ŠĢ16.€Source:€International€Commission€on€Radiological€Protection€(1983).€RadionuclideŠ ä4 ŠTransformations:€Energy€and€Intensity€of€Emission,€ICRP€Publication€38,€Annals€of€the€ICRP,Š Š  ŠVols.€11-13,€Pergamon€Press,€New€York,€NY.