‘_ UNCUSSIEED, (SE EL IMDM! 2EMARNS: At the plannins conference at Kwajalein cn 20 april radiation levels at ues rix sight allow 2n early return of agresagrecd tha it wes t the natives, Accordingly, it was decided to mike a field study of food and water as well ag an extern) radfation survey based on the pattern exaleyed at Rongalap, 2, METHODS: Fxternal gums dose rotes were aeasurod with AN/POR=39 and MX-5survey instruments, These inetrum@ts gave readings in geod agreement with each other, Aver2ge readings integrates over the exposure tine close i Soe eee yea a ance ’ Tr moeytiennerrnr near = a seem ke cee NEPOYTE = — checked dosineter readings, 3. DOSE RATES AND DCSES: Prior to this survey, ne standard positions vere established a this isiznd, a standard positian was established om April 23 at 1100 hours. The reading at this point and three feet adove the ground «25 3.0 mr/br. An average reading in the _vegotated area cf the island was 2,3 =r/h The readings ateut the duildings where mr/hr, formula: gravel is prevalent averaged atcut 2,2 This data with the ma2suromentsenade on 4 and LL March fit a deary Dpz2cr7t.42 p/day (t in days alter 1 Magch) This forml2 indicates that a level of 0.3 r/weak would be meached in 7§ to & days after 1 March, 15-20 May). an integretion of the expected external dosage froa l June 1954 to 1 Jun 1955 gives a 3.4 r exposure. This c2n be campared with the 3.9 r extemal gars per year Level estadlfshed cy the ataaic Enercy Ccomission 1s a linit for off-site pomilatiaons, The incegrsated what mt external ga=m2 dosage over the year beginning 1 June caild ce sanewhat, ie gtmificnvy, higher if the decay rete leveled aff to the conventional tr4-4 fo ro pate, 4, DISTRISVTICN Ce CONTAMDIATICN: The contanination was fairly uniforcly distributed cre: the island, The highest reading ost of doors at the 3 fset elevation wes 3.3 mar/fhr and the lowest was 2.0 mr/hr, There was sone reducticn in redings andoors , and this reduction was substentially lzirger, 60 percent in a large building like the church, 2s cenpered with 2 smell building like a typical dwelling. Gravel areas (2,2 ar/hr) give lower readings than the grassy arers (2.8 mr/hr), The sleeping sats showed gamma readings (1.C - 1,2 ar/hr) about mir the levels outdoors (2.2 - 2.4 ar/hr) cut bet2 plus gaeza levels were somewhat higher (3.5 ar/nr) thin the cutdoor game readings. Contanin of the thatched roofs was acted, It wes necessary to place the instruz elese to (less thon 3 feet) and perpendiculir to the reof surZice te ccosistently detect this effect with gasm: measurecants. The MC-§ pickad up this increzse in ccstaminatican more consistently when detecring both beta and gasms3, UNCLASSIFIED