nye rrr oe . —— “er ‘ = a4 perenne - e t s m e r e m c e s a < D E I F I S S A L UNC dvegen to apoear when the instrument wes within about sie (nches frem the r ~~ ~ it seened unlixely that deccntasiniticn of the roof would effaet any subsite4tee" reduction of exposure cf innabitants ina Tut ry HONGELAP (ND «ILINGN.S (CONT'D) <r I. > ° A crude attenpt was made to ascertain dépth of poner of radio: layer had about six tizes the activity of the secmd, It is quite possisl. that all of the activity in the sececnd layer my have come from spill2s: during rencval of the first layer, an effort was sade to ecllest an even thinner layer. The technique was aven nora unsatisfactery, but the results indicated that the activity per unit volume was seveml tires greatersin the thin layer than in the first inch, (me cin cecnelude thet thers wes very little if any activity belsw two inches, end that the activity nay ce entirely superficial, §, DECHTAMEATION: Since the stete of the vegetation and the cistern indicated that there had teen Little if anz rain cn - island, an sttanst wes rade to find cut whether future rains aight eff neticn, zny mnatur2l decentani- The shiy:'’s crew zeunted 2 rertable 2 eoLinesdr iven water-punp on t!7 besch, connected a hose, and scrayed salt water cm the thetcned roof of cne mut, and on a neighboring gravel area, The contact reading on the rocf of the hut was reduced by 10% (after suttracting the generel backzrcund fr:a the readings, this indicates apere<imately 25% decomianination of the roof but there w2s no noticesdle reductisn in contact readings an the flocr sf mut or cn the washed—dewn gravel area. while this exper inent cannot te regarded as camclusive, 1% suggests that one should not be optinistic 220. the effect of future reins, It sheuld be noted that cniwetok Atoll expert: on this subject is conflicting. Dering Cpzration Greenncuse, the heavy rs just pricr to George Shet hed Pyass ze effect on the Dog Shot fall-cut, Sut t rains that fcllowid socn after the departum of the Task Force 2prear te has been fairly effective, However, even if the experience mad ceen cansistert, the terrain surfaces it Rengelap ond Eniwetck are so differen. that it «mild be umsafe to draw conclusicns, It was evident thet any attemst at artificial deccntaminatian would be difficult and very expensive relitive to the cest of susrerting che posabicica elsewtrere until radicactiva dessy has reduced the radiation to an secactabl- level, Decenteminsticn oprritions cf the type used en Iniwetck Atoll (all- dozing and griding) would not be acplicable because of the total destrcbhitn of all vegetation 2nd severe crmtge to the thir tepesoil tn the area covercd, Any seiscribdle aaedestructive deccntaminaticn effort would rave ta 58 2 manauil jos, orOrr rr =v Sr. peeeel, Le el -3- Hi UNCLASSIFIED 24 ere ee inch in thickness wis scooped up, each layer being mt in & separste enn, then the radiations from the cans were canpercd on the teach where the background was such lower, The third layer had no cetectable activity; the fo: + eee. ee aay The plece chesen ws Successive layers of about crm ee en pene + nee epeeem eet ae tir een ots pt wee ne tea 507 ays Een, a . — ee nee ee SR ReAYee ot rey ae tm ae RE & ORR fi. coe Smee ee RT eS te in 2 patch of soil near the center cf the villegs, bare patch of loose scil in a prassy area, te w ee wee. as v - F ee