Table of Contents Abstract.........00entssecossessessccsacssecsesescasscssoussssesasseceanseneseetessssssesssssassnenseaeseecaescaesceseretensecafbesesears1 INtTOGUCTION........ cecsetsesessssesetssrsasssessesescesessscsusassensuscsssstonsesssscecerssssesstecosssssasseessssensenedfercneese 1 Exposure Pathway.......c.csccssssscsssssesesssesesssssssssssesessssssessssesstecerssscestesnsocenssacsesssestensessseeefbeasesees2 Data Bases.........:cscesscccssseressscsrssscseessesessassasenssscerssserecsscussesacssesusensusssssssasessssosegsesssseseresseepbesseeses2 External Exposure MeaSurementt...........ccsssssssccsssceresesstsssssssessseensoscasesessceasasseeeffessenes2 External Beta-Particle Exposure...........scsssccssscssssssscscsssessssssceesssescseetssecssesacceseeeepieressees5 Airborne Radionuclide Concentrations...........:cc ccsscssesssssseescossenscssensneessenseae feeesscees5 Radionuclides in Drinking Watet.............:ccsccssssscccssesssssssscssessesssessceseresesssererdeessesees8 Radionuclides in Marine Foods............::sssssssessesscsesssscsesscessssssssesseresecssessessetacaocssseses8 Radionuclides in Soih oe sessecseesssecesssesscsesseessnseesesserecessseesssceassnsseetscesedfeseeees 16 Radionuclides in Terrestrial FOOdS ...........scsscscscsssesonssscsssessscesesscetssseassssereresedfecseees 16 Diet .......scesssesssescsesesesessscscssssseeetssssssssnsesecsssenssescsonescossessscesesscecssocsessessescesatsseesesensseeceedfecsenes21 Dose Methodology...........cssesssssossessrscecrsesesssscssesssnsscesscessseeessssessssnsecsesssnsesesersseceresedboesenss24 External ExpOSure........sccccccssssssessessesesessseecessssssscesescsrecsueessatsssscesesssrscesssnsssaesseaseeffessenss24 Gamma Radiation...ccsccssssesscssscssessssssssssscsscssceessscsessacstsseseenssseseasee|fieseees24 Beta Radiation...cccsessssscscssscsssseescenscsssssessseassceesrscceseseaseseanassceseafecesenes25 Internal ExpOsufe.........cccccsesscscsssssssssscesssssesecesssecesssccesscesisssssessssscsssssscessseessseerssedpessessee25 COSTUIMNH137..........:ccesessssccecetcessecscesescsseersessescesacensessenecessenscessssnasecesenesssssssesesasedfsnsseess25 Stromtim90 ..0...neeeesesseccecccesesesesesrseseecececesscecsssscatseeneseseneeesseasseetatseeetseeedfceseses25 Transuranic Radionuclides (239+240Pu and 241 AM)...cscs ceneffeeeseees26 INGESTION.........sccsssessssrscsersensecesssssscneccneetersersscstusnonsssssessessesesensseseseasessepbersessee26 Trnfalation i...cccccssescsesesssensescescsessccssscsstsesesssceseseasseassssesessssetseeepbessseees26 Polonium-210, Lead-210 0...escessctgecsesesscssecsrscecsessscescsseeeacceesstssossscscenenppasseeees 26 Body Weights and Biological Half-Life of 137C 0... eecscssscsseestsscenesssseececeppecesones26 ROSUIES........ccsecesesesscecsssccsesecesecsscvssesenesesssessscsecessssesusaseesesesesesucecassiesecesacseeatecnensicsernsececeffeesesenes28 DISCUSSION..........sscssscesessecsscesessscesecsecseeseesscseseessassestesssnenesssssesssestesssessassenstestensessteaterstesedfscesseess30 Comparison of Estimated Doses to Adopted Guidelines and Background DoSes.........s-ssscsscrsscnsecnsssneesncccetesecsenstsonssecnissacscnnessesnscnsssnsssassasereesfienesenses30 Relative Contributions of Exposure Pathway............sssssesssssesesssesssersssesepbessenness33 Mitigation Of Food-Chain Dose........ccssesssssssesstenssetsceseessessssseatsenssessesessseedeeessesss35 Environmental Half-Life of 137CS..0..00...eetesceseeseeeseseeseeessesecececsoesseeseeeeceeecenffesessaees36 Uncertainty and Interindividual Variability in Estimated Doses..............f....037 Remedial Actions ..........cscescssscssssssscssssssesscerssssseesensscossssasescssssescesansessseseeneseeraseseesferseeseess51 Acknowledgments........sscsssccssscsssssensecsseesersssseesesssacuneatecsacsescasesecsecensuseesceeesceseatsseceseepoessereees52 REFETENCES........scccesscsessecessesssssecscesscsessesessssssoresssecssess ese sesessesessessessecsceesnerecsessscessesatsseerseerses53 AP ndix A: Radionuclide concentration summary ofall soil profile samples collected during the 1978 NMIRS,and from 1986 through 1993............00feceees A-1 Appendix B: Concentrations of radionuclides in vegetation from samples collected during the 1978 NMIRS,and from 1986 through 1993............:ssefbecrseesB-1 Appendix C: External dose at Rongelap Island in Mremm............csssssssesereeeefpeceeseseC-1 Appendix D: Mathematical Appendix ...........ccccsscsssesesssessssesesssesenecnseneasseccactceffensaces D-1 iii