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4. HÃL8H^ LXr03INL 10 c^iM^. ^Iw LLL^ l^V8 ?or all practical purpo8e8,onlv tvo mean8 ot entrance into tne animal'8 bo6v nee6 de con8i6ere6. Inev are (l) indalation an6 (2) inÃe8tion. 4.l Indalation Na2ar6 3neep an6 6oÃ8 expo8e6 to tallout trom 8urtace an6 un6erÃroun6 6eto» nation8, vnere tne animal8 receive6 external Ãamma»ra6iation expo8ure8 8everal time8 tne letdal 6o8e, 8nove6 minute an6 in8iÃniticant amount8 ot ti88ion pro6uct8 internallv. Verv 8mall quantitie8 vere od8erve6 to de re» taine6 in tne lunÃ8 or otner internal orÃan8. ^ 8im2.lar pattern va8 od» 8erve6 in tne Kar8nall I8lan6 animal8 lollovinà mo6erate Ãamma»ra^ expo8ure. tlea8urement8 on in6iÃenou8 animal8 at tne Heva6a Ie8t 3ite in6icate tdat indalation 6oe8 not contridute an important portion 01 tne uptake ot ra6ionucli6e8. 1^doratorv experiment8 in vnicn mice innale6 8imulate6 ra6ioactive 8alt vater tallout ot ionic tvpe (mean 6iameter l.8^; maximum 6iameter 3.?^) 8dov tnat tne relativelv 8mall uptake ot li88ion pro6uct8 an6 tneir 8nort ra6ioactive an6 dioloÃical nalt-lite in mou8e ti88ue8 lollovinà a driet expo8ure (one dour)re8ult in a relativelv lov internal 6o8e. Ine maximum internal 6o8e rate at one dour to tne re8pirator^ 8v8tem va8 2.2 ra68/nr «nere tne external 6o8e rate va8 l700 ra68/nr. Ine da2ar6 trom re8piratorv a88imilation can, tderetore, de iÃnore6 in an emerÃencv 8ituation. Ke8u8pen8ion value8 in tne environmental air (uc per cc/uc per cm^) lie detveen lN"^ an6 lO"^^ , vitd l0"^ tne mo8t likelv value tor 6u8tv operation8 in tne open. In expo8ure8 occurrinà in a neavv-iallout reÃion vnere tne external Ãaimna expo8ure i8 adout 200 r/nr at one dour attei? 6eto» nation, tne indalation da2ar6 i8 al8o 8liÃdt. Ine expo8e6 man or animal voul6 dave to dreatne in all tne indaladle ra6ioactivitv tdat voul6 dave deen 6epo8ite6 on l0 cm^ 01 8urtace to 6eliver l5 rem in 90 6av8. Idi8 e8timate aÃree8 vitd 6ata on tne Kar8nall I8lan6 animal8 an6 vitd otner e8timate8 ma6e in tde pa8t. One miÃdt 8peculate tdat tne da2ar6 voul6 de Ãreater in Ãra2inà animal8 decau8e ot proximitv 01 tne external nare8 to tne Ãroun6. Novever, a tactor ot adout lO^ mu8t de applie6 in or6er' to place tde ra6iation 6o8e8 in or6er8 ot maÃnitu6e 8imilar to tdo8e trom external expo8ure8. 25
4.2 In«e8 tion Na2ar6 Un6er expecte6 con6ition8 ot tallout tne muco8a ot tne inte8tinal tract miÃdt receive a larÃe ad8orde6 6o8e, primarily trom deta ra6iation, a8 ra6iocontaminate6 inÃe8ta pa88 tnrouÃd tne 6iÃe8tive tract. ?rodadlv tne larÃe8t 8ource ot inÃe8te6 ra6ionucli6e8 tor Ãra^inà animal8 vill de 8ucculent Ãreen toliaÃe. Kore mav de a66e6 dv tde contaminate6 vater con» 8ume6 an6 dv ra6ionucli6e8 8vallove6 atter deinà taken into tde do6v dv indalation. 3tu6ie8 dave 8dovn tdat tne lover larÃe inte8tine i8 alvav8 tne critiical orÃan in dotd tne 8inÃle»8tomacne6 animal an6 tne ruminant. Ine pnv8ioloÃical 8tate ot tne Ãa8trointe8tinal 8v8tem (tor example, vnetder tnere i8 6iarrnea or con8tipation) alter8 tne 6o8e 6elivere6 dv more tdan an or6er ot maÃnitu6e. ^ltdouÃd 8erial 6ailv 8acritice ot 6oÃ8 tollovinà inÃe8tion ot 25 mc ot ^^ 8dove6 mil6 patdoloÃic cnanÃe (8louÃdinà ot villi tip8 , neteropnilic intiltration), tne ti88ue8 ot tne lover larÃe inte8tine vere e88ential1v nor>»al in tde animal8 kille6 on tde 8ixtd 6av iollovinà a6mini8tration ot tne ra6ionucli6e. Ine total 6o8e to tde critical orÃan in tdi8 ca8e va8 2000 ra68. It va8 not until tne 6elivere6 ra6iation 6o8e8 reacne6 5,000- l4,000 ra68 tdat nemorrdaÃic enteriti8 va8 od8erve6 at autop8^. It na8 not deen 6etermine6 it 8eriou8 incapacitation8 or 6eatd8 voul6 occur at tde8e 6o8e level8 amonà animal8 in Ãeneral, altdouÃd one miÃdt expect a re6uction in milk or eÃà pro6uction or in veiÃdt. Io receive a Ãiven 6o8e trom deta ra6 ia tion, tne ruminant mu8t inÃe8t Ãreater total amount8 ot ra6ionucli6e8 tdan voul6 de nece88arv tor tne non» ruminant. Ini8 i8 decau8e tne ruminant da8 a Ãreater ma88 ot inÃe8ta ot vnicd onlv tne "outer 8nell" irra6iate8 tne muco8a. It i8 tne concentration ot tne ra6ionucli6e8 vitnin tne inÃe8ta tdat 6etermine8 tne 6o8e rate to tne rumen muco8a. ^l8o tne Ãut 6o8e i8 a tunction ot tocxl intake, inÃe8ta 6vnamic8 (6edv6ration, nol6-up time8, etc.), amount 01 ra6ioactivitie8 pre8ent, an6 ra6ioactive 6ecav. Ineretore tnere are Ãreat 6itierence8 amonà 6iiterent 8pecie8 in tne ra6iation 6o8e8 6elivere6, particularlv to tne lover larÃe inte8tine8, dv tne inÃe8tion oi eczual amount8 ot ra6io» nucli6e8. 1,ikevi8e con8i6eradle 6itierence8 are note6 vitnin 8inÃle 8pecie8 decau8e 01 innate pn^8ioloÃical 6itierence8. L8timate6 accumulate6 6o8e8 to cov8 re8ultinà trom tallout level8 ot l00 r/dr 8tan6ar6i2e6 to one dour atter tne 6etonation are li8te6 delc>v. It da8 deen a88ume6 tdat tne cov8 tnat dave deen kept in a darn tor tne tir8t l4 62V8 atter attack dave deen te6 on uncontaminate6 dav. ^ tactor ot tnree da8 deen u8e6 tor tne 8niel6inà ettect ot tne darn aÃain8t Ãamma ra6iation. 26
0ov8 8tart Ãra2inà 0ov/8 8tart imme6iatelv aiter attack ssra2iii« at l4 6av8 90»6ay v,dole»do6v ao8e 400 r l50 r 90»6ay Ãut 6o8e l00 r 30 r It da8 deen a88u>ne6 tnat 560 mc/it^ oi Ãro88 ii88ion pro6uct8 (6l00 mc/m^) vill pro6uce l00 r/dr at one dour aiter 6etonation. Ini8 6e» cav8 to l5 mc/tt^ tne tir8t 6aV. It da8 al8o deen a88ume6 tdat tne nerdaÃe retain8 at>out one per cent oi tne material I2llinà on tne lan6, an6 tne cov 8trip8 l500 tt^ per 6ay on an averaÃe pa8ture. Idu8 a total 01 225 mc i8 in«e8te6 eacn 6ay vnen re6uce6 to tne one»62v activitv rate. In 8ituation8 vnere tne nerdaÃe retention i8 niÃner tNan one per cent tde 6o8e 6elivere6 to tne Ãut vill de increa8e6 proportionatelv, dut tne vdole»do6v 6o8e 6e» livere6 vill remain tne 8awe. Ine vdole»do6v 6o8e i8 relate6 to tne ad8o» lute amount ot ra6ioactive material tnat iall8 an6 i8 not altere6 dv tne amount retaine6 upon tne nerdaÃe. It 8doul6 de note6 tnat even a vdole» do6v 6o8e oi l000 r voul6 mean onlv 250 r to tne Ãut; l/8 01 tne 6o8e require6 to pro6uce tne minimal in^urv note6 adove. l^doratorv 6ata odtaine6 trom Ãoat8 in tne vttrium-90 experiment8 note6 adove mav provi6e 8ome in8iÃdt into tne comparativc deta»ra6iation 6o8e8 to tne cov'8 lover larÃe inte8tine vnicn one miÃdt expect irom ti88ion pro6uct8. Lacn millicurie oi vttrium-90 inÃe8te6 dv tne «oat re8ulte6 in an ad8orde6 6o8e 01 l? ra68 to tne lover larÃe inte8tine. Lv 6irect extrapolation ot tde8e value8 to tne cov, 225 millicurie8 ot vttrium-90 voul6 6eliver le88 tNan 4000 ra68 to tne critical orÃan. Ini8 i8 le88 tnan tne ra6iation 6o8e require6 to od8erve patdoloÃical 6amaÃe (nemorrn2Ãic enteriti8) in tne Ãoat. Inere are 8everal iactor8 tnat voul6 re6uce tni8 e8timate6 6o8e to tne cov. ?or in8tance, tne in«e8tion ot tallout material le88 tnan t«o an6 one dali 6av8 ol6 (tde approximate N2l1» lite ot vttrium-90) voul6 re8ult ln loverinà tne 6elivere6 6o8e, 8ince tne nalt»liie ot ti88ion pro6uct8 approximate8 tne time 8ince tormation. ^l8o, a cov voul6 N2ve to inÃe8t more ii88ion pro6uct ra6ionucli6e8 to receive tne 8ame 6o8e a8 tne Ãoat, a88uminà 8imilar 6iÃe8tion 6vnamic8 , 8ince onlv tne outer 8nell contridute8 to tne deta»rav 6o8e to tne inte8tinal muco8a. In a66ition, tne averaÃe deta»rav enerÃv ot ii88ion pro6uct8 i8 e8timate6 to de 0.43 tIev at 2.l 6av8 o1 aÃe compare6 to 0.89 Ilev tor vttrium-90. Ini8 6itterence in deta»rav enerÃv voul6 «reat1v re6uce tne 6elivere6 6o8e. In 8ummar^, it appear8 tnat tne cov voul6 receive a 8ut>8tantiallv 8maller 6o8e to tne Ãut tN2n voul6 tne Foat. In viev ot tne 6ata odtaine6 dv 6irect 6o8e mea8urement 01 inÃe8te6 vttrium-90, it appear8 tnat tne vdole»do6v ra6iation 6o8e voul6 prodadl^ re8ult in iatalitie8 lonà deiore irra6iation ot tne Ãut voul6 decome a critical prodlem. Novever, tni8 6oe8 not 6i8count tne po88idle a66itive 27
ettect8 ot vdole»do6^ an6 Ãut irra6iation, nor 6oe8 it evaluate tde ettect8 ot Ãut lrra6iation at tde non»letdal level on veiÃdt Ãain, milk or egà prc>6uction, 8u8ceptidilitv to intection, etc. Ine pd^8ioloÃical 6i8turdance8 re8ultinà trom lrra6iation»in6uce6 6iarrnea coul6 conceivadl^ re6uce or 8top prcxiuction in tde milk co« or la^inà nen. Keciuction8 in tde potential Ãut 6o8e can de accompli8ne6 d^ tee6inà le88er amount8 ot contaminate6 rouÃdaÃe tee68 8oon atter 6etonation, or d^ vitddol6inà all contaminate6 tee68 tor a8 lonà a8 po88idle. Ine local 8ituation vill 6ictate tde more a6vantaÃeou8 metdcxi. 1,ikevi8e, tde a6min» i8tration 01 a laxative tollovinà inÃe8tion 01 ra6ioactive tee68, it non» contaminate6 or le88»contaminate6 tee68 are availadle tor 8ud8equent tee6» inÃ,vill reciuce tne 6elivere6 6o8e to tne Ãa8trointe8tinal tract 8noul6 tni8 decome an important con8i6eration. Ine Ãamma»ra^ 6o8e ot internallv-locate6 ti88ion pro6uct8 6oe8 not appear to de 8ud8tantial; it8 contridution to tne total ra6iation 6o8e receive6 d^ a ti88ue i8 8mall vnen compare6 vitn tne 6o8e a88ociate6 vitn deta»ra^ emi88ion8. ?or example, in 6oÃ8 a6mini8tere6 ce8ium-l27, tne deta/Ãamma»ra^ ratio 01 6o8e to liver, ki6nev, mu8cle, an6 Ãona6 i8 approximatelv tvo. Io a Ãreat extent tne Ãamma 6o8e i8 a tunction ot tne Ãeometrv ot tne ra6iatinà me6ium (inÃe8ta): tne nearer tne approacn to tne Ãeometrical center, tne niÃner tne Ãamma»ra^ 6o8e. ?or tne larÃe animal (e.Ã., cov) tne ra6iation 6o8e irom tne Ãamma»ra^ component ot tne inÃe8te6 ra6ionucli6e8 vill decome more important decau8e ot tne 8i2e ot tne ra6i- atinà me6ium. Ine contridution ot tne total 6o8e d^ Ãa>mna ra^8 i8 a88ume6 to de 8implv a66itive to tne deta»ra^ component trom inÃe8te6 ra6ionucli6e8 ot ti88ion prcxluct8. It tdi8 i8 true, tne total ra6iation 6oZe un6er 8pecial circum8tance8 ma^ approacd in^uriou8 level8 in cov8 decau8e ot tne comdine6 expo8ure ettect8. It i8 not delieve6 tnat tni8 i8 a practical po88idilitv. lor po88idle Ãenetic 6amaÃe, tne Ãamna component voul6 un» 6oudte6l^ a88ume tne more important role. In 6ome8tic animal8, in an emerÃenc^, tni8 i8 not con8i6ere6 to de ot an^ particular importance. ^.2 Ine ^6cle6 Na2ar6 to ^nimal8 ot 0on8ume6 ?J88ion ?ro6uct8 Inere na8 deen no experimental 6etermination ot tne a66itional dur6en tdat an animal externallv expo8e6 to tallout voul6 8u8tain trom a deta»ra^ 6o8e to it8 tdvroi6 an6 trom a total»do6^ 6o8e trom inÃe8te6 icxiine»l3l. Inve8tiÃator8 dave ma6e e8timate8 tdat varv con8i6eradl^. Novever, all are in aÃreement tnat tne dioloÃical ettect contridute6 d^ tde icxline»l.3l to tde td^roi6 an6 to tde total dcxl^ i8 comparativelv 8mall. Ine external do6^ expo8ure to Ãamma ra^8 trom ti88ion pro6uct8 vill alva^8 de tde limit» inà tactor in an un8neltere6 8ituation. 1,onà detore tde internal 6o8e reacne8 8ud8tantial proportion8 tde animal vill dave receiveci a tatal expo8ure trom amdient tallout ra6iation. In viev ot tde 8cant 6irect 28
evi6ence dearinà upon tni8 8ud^ect, e8timate8 tor all tne important ti88ion prcxiuct8 are Ãiven in ^ppen6ix 0. ?rcm> tne8e ^ppen6ix 0 e8timate8 an6 trom calculaliion8 in ^ppen6ix v, vkicn ve delieve maximi2e line na2ar6 ro animal8 an6 man trc>m tne inÃe8tion c»t ti88ion pro6uct8, it appear8 tnat tne 6irect or in6irect a66e6 na2ar6 traul con8ume6 ti88ion prcxluct8 can de iÃnore6 in dne earlv pna8e8, an6 vilin clo8e»in tallout. Ineretore, it tne population nee68 too6 tor 8urvival or tc> maintain a capacit^ tor vor«,tde too6 proänct8 trom animal8 rnat nave cc>n8ume6 ti88ion pro6uct8 can de u8e6 6urinà an emerÃenc^ pericxl, provi6e6 Hdle animal8 can de nan6le6, milke6, or 8lauÃntere6 vidnout exce88ive ex» pc>8ure to tne nu8dan6man. Icxline»l3l in milk, novever, po8e8 a 8pecial prodleM tor 8mall cnil6ren, a8 i8 6i8cu88e6 later. 29