Radiological Surveys of Several Marshall Island Atolls, March 8, 10, 12, 1954

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SUBJECT: Radiological Surveys of Several Marshall I&md AtoIls 1. A~tached here~ith for Your tiformtion and retentionare copies of radiological surveys made on certah Marshall IsGmd Atolls. The surveys were conducted as a result of contaminationdeposited on the affectedatolls byERAVO Shot, Operation CASTLE, fired from a reef apprm&ately one and one ha~ nautical-s southwestoflkmu, Bikini Atoll. BRAVO Shot time was 2. Water and soil sampleswere shipped to tbs Healthand Safety LaboraMerrill Eisenbud) for analysis. - t 1. Report on Soil and ;IaterSmpling “-~ 2. Report on Soil and ;“iaterSxnpling I 3. &d. Survey of Doti-::indAtolls Centaminated

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SAN FRANCISCO, CALIFORNIA Ii In compfince with your oral htructions, the undersi~ed visited UK measuringIe%l of -. ra~ttin present at those places in connectionwith sites and returned to Blldx&, where the remainder of the trip to Eniwetok was p formed by HIM. There follows a detailed discussion of the findingsat each 10C a. UKIEP A’TO&. The sampleswer% taken on Lildep Island, which had t largestnative po@time Access to the lagoon was gatied_ttioughSouth Pass. poor light at the end ~f the daY_~d numerous.coral heads necessitateed anchorin about4 mj.1.es from IdJae,pIsland., Trip in was made by whaleboatthe fotiwing readingwere noted m clofifig or bare feet of.inditiduale, Accord@ to accoun and blast wave; tk htter ~fih rqa+=dly arrived abmt 30 minutes subsequent to the light flare. Accmding to Rishop Feeney, ~urch attendance~s great~ heavy s~f on three sides. There being no place for lan~” a vtuileboat,perscn and equix were trmsferred~ra the Wklebat to the reef by a tie ~ rub~ raft. The undersignedtransferredhtielf by sdnndng. The island proved to be severplhouses,a rati ~rre~ of which provided a water”ample. Earth samples were gatheredat “randomfxmm open areas, includingone of beach sand above the hi@’ tide ~rk, The party was led straightacross the island and back to the LN ing arm via the beach, ti order to verify its _nbited state~ .%mplos .WCZW

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kcollectedat approfite v 12C0 M, 6 March 1954. Instrumentreadingswith the X showeda mD51numof3mr , however this was not ccmsidcredreliable, since a higher scale showeda lower r=ding. AIMK AT@L. The ship reached this atoll at approdnntc~ 1600 M, popuktcd. The lagom has not ~cn swept, and nummous corhl heads and pinnacle providedconsiderablehazard to ~ip mvcments The landing ~rty moved nshorc b; mt cistern Canalsoil samplesfrom random unsheltered spotsl Readingswith the K readingof ~-mr~, however, on a different scale a r~~ of ~ or 15 ~k wa obtained. me MX-5 readingis probbly nearest corrcct. No signific~t ~r~tit taken at approdrately 1700M, 6 krch 19540 i d. MEJIT Island. Thik singl.ocoral island is also surroundedby a ZX+ the surf. The islandwas found to bc heavily populated in view of its size, the ‘.otal number of people being 327, according to the island migistrates~SOfl “ad with a PDR 27 E was 10 mr~r. The true figurc was probably somowhcrobotwoen th promd complctolyuselessnot hokiing to zero even after an hours war-up,’ and to persbnml and quipnent.” This will por+t landing direct~ on live coral ree with.less dangoi of the boat being .stovc in. -Shipsassigned to such missions shoulddraw such cquipncntprior to departurcc “- “’,.. to the mission,however,“the‘my Valuabb suggostims and assistancein mlutic of problemsproved invakble. ,.

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on -Soil and Water Sampling Mission Erikub,&loolap, Wotho, Wjuro Atolls in tho I&rshcillIslands 5 through 7 MaI 1954for the purpose of obtaining outh and drirddng water samples,and of mm RcQUE on its arrival at Majuro 7 March 1954. 2. Tho first four atolls wore tisitcd by MarshallcsointcrprctcrTakushi C-47. Erikub might haVO been omittcd sinco it was not inhabited,boi.ngpropor of tFn Wokjc tribc which goes thoro only occasionallyto gather copra. (This urhown until aftor tho bit. ) 3. At C=h ato~, a~ tho prbcipal hhabited island was tisited. At c visited island an effort was made to compose a rcproscntativcsoil avcrago by I colloctbg into a singlecontairmr sovcral sam@cs, each apprat cl,yao squ foot of arcs and one in~ depth. Water samples woro collcctcdfrom tho princi sourcescurrentlyh “use. Tho gamma doso rates aro avcrcgos for t~ inhabited.. 4. With regardto certab tier dscrcpancics bctwocn tho ~wy nmthods by Major R. D. Crca and the writer; it was originally plannod to perform the SI jointly,and when it hecamo advisable to sc~rato and survey cliffcrcnt atoils, “50 &ma-ray doso rates on Wotje and on Eyikub aro each the avcrago of Ml inopcrativo.when the rubber 1330 raft was ‘Swampedby surf on-$hc first attempt range arc of wry dubiousreliabilityy. on path to boachi No inlia ants, no water supply fetid

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From catch basin. Well water (no rain h catcl basin for 2 me.) 0.5 mr/hr, 4 from near Admir Guam, tift Ebcyc 0840 b!on 1 March, cntorcdchamol to Uttiik lagoon abcti 1200 on 2 Wrch, and anchord ti hgo~ at 1524 M on 2 March; dockod at llk$uro(UligZ Is.) 163aJ m 7 ~rc~o Rcatigs (mrfi) after docmg: 2-3 inside main deck stI but th-.t\t was undestiab~ to have it aromd longer than necessary. t axpcricnccin such opcra%ionsis very Ibitcd, but from his own obscrvatias plu tho ranarks made by those ~tter qua~icd to judge, it appears tht a fair amm pcrtti this mission.

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At each island visited sovcral sainplcswere dug and put into tho samo squaro foot to a depth of onc inch”, The nticr and locations of the samplesw sclcctcdto rcprcscnt”,as well as could be judged, an average of the areas USO by the inhabitants,aftcr the sqlcs were hod in tho carton. Areas that we: unusually shaded or unshadedby trots were avoided. ~c large flpebblcsl~ti the composite rcprcsent coral grevcl from Wdn streetn through tb vi~gc.

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The hors of the survey tcamtish to express thch approciatim to “t officersand members of the crow of the USS NICHOL’M (DDE &9) for tha assistanceand cooperationin conductingtho survey horcin roportcd~ Captain Elliot turned over all pcssiblofacilitiesof his ship in order to assist b tlx LT Frink, tho Exccutivo Offticr$ organizedau the OPOrati~S Of tho that it was possiblo to carry out the small boat surveys under cxtrcndy diffic C=ditions, Since most of the lagoon -tcrs woro not navigable by a ~E, it WS: ncccssaryto make long bat trips @ high seas and land on tricky cml reefs. separatedatolls in tho courso of three days with only two boats ms largelydu Tho BRAVO Shot contaminateda number of atolls in gcm rally eastward .— ..— -.dirvetionfrom Bikini to such an extent that it bocamc ncccssaryto cvacuatoth native populatims fmm Rongelap,A13nginacLand Utirik Atolls and tho milltary persmcl on Rongcrik Ato31. Following this evacuationCJTF SEVEJ organizedtl subjcct detailed radiohgical survey of tho atoils to tho eastward of Bikini a. The evaluatbn of the miiation effects on evacuccs. b. The ostimatia of tho elapsedtime before rcoccupancy~ c. The cstbatim of tho residual radiationcffeds of large @cIds Wilds, Trust Tcrritcry with this survey, teams fran various Task Groups and Mr. in Rongclap lagoon.

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MoO Two parties in snnll boats surveyed Iltig area on Rongclap Island and eastern half of Rongclap Atoll 1130 Two parties in s~l.1 boats ~occcdcd fnm the I which w.s stationed outside Utirik Atoll and survcycc Utfiik and Aon Islands, the mdn islands of the Atoll 1700 Onc party in a small boat landed on tho outer reef of Bikar Iskmd and surveyed the island, the OL largo isbnd of Bikar .\to31, UXl Two parties in amdl boats procccdcdfrom the 1 which was stationed outside Rongcrik Ato11 and survc: stationed)and tho other important iskmds of the Ate: 1900 Two parties in samll boats procoodcdfrom t hc z which was stationcd outside AlinginacAto1.1and survc the inhabited islands of the AtoW orn islands of Rongclap Atoll and onc party mchcc kcci tho living areas on Rongdap Island and cstx~bliahcda rofcrcnco location for futurc decay mcasurcmmts. Survey team arrived Miwotok Atoll W DDE. f tho sur~Y. Fivo (5) each of AN/PDR-39wcro calibratedtith an 80 ~o~o survey~tcre wcro subject to prolongod uso under advcrso condicftiimt~ f~ the durath’ of tho opcration~ On the fbal day it was found

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-“~/pDR-39~still o~rat=d cff~cicmtlyand sccud to be ti good worldng order, for any low intcnsity ch~’c~ ncccssary. Two (2) each mllbratcd /IN/PD%TIB,WCJ waist height.~lc 56 othcxsc indicated. The rmximum readingsdo not bcludo ~ surcmcntspadc with t.~~~st~nt nti to a contsainatcd surfacoa readingsaro given fi Ta~\+cs.,1 and 2 for tk nativo-villago of Rongclap Island, shacks was l/3 to l/2 th=t Outside. This rcducticnis probablyhrgcly a gcom War northom cistern 3%

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In order to estimate tho rate of decay between $ and 11.March, the XolloR @ radiationm=asurem=ts were takeq m three days on Rongclap Island: /m area was se~ctcd 30 yards tiknd from the lbngchp cometcryaa a nnae ing point for future decay measunmcnts. This area is outlinedwith ~a plac w pils. The waist height Nati wa$ 210 mr/h.rat 1000 hours, 11 March 1954 Water sampleswere collected froa the vmtcr suppliesof all inhabite{. each sitm. These wi12.be turned over to the New York OperationsOffice$.AEC f , analysis. —. .Soil sampleswere collectcd at afi inhabitod areas and also at seven uninhabit@ islands, h: collootingtho so= samplesa one foot by onc foot squro was ma-on the gromd and sdl to about one hch of depth was remova Hstcd in Table 3 arc the samples taken with the dose rate measured.. at waist height at tie ~ati~ *CrO they Wro t-. Rongelap (Center of village) +FWn additionalsample taken for analysis

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Rongolap (North part of Utirik (cistern at south of In additi~ to the ative, a =MPIS of foibge was takcnat the Wh ward side d EiikarIsland. The radiation field was 180mr/hr on 9 March 195 at this point. b. he center of the”contaa~m pattern from the BRAVO Shot lic c. Althou@ the f&lLout was asrious a Rongelap Islandlocated at gr~.ter at the north side of the atoll, twenty miles away. e- standardfltary ffild housing provides a significantdegree o f. The AN/FDR-39proved to be a very satisfactory i.nstrummt for field survey work under rigo~us en~-ntal conditions. factory method of c~d~t~ a broad ratiolo@cal’survey of the type jwt 2. Rad. Survey Utirik DR. HEREERT SCOVIXKS 4. Rad. Survey Rongerik - 6. SmIMry of Rad. Survey