Memo to Files, Subject: Preliminary Trip Report-- " Bikini Atoll Environmental Survey-1976 "

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UNITED STATES GOVERNMENT Files DATE: Ihy 26, 1967 Arnold B. Joseph, Marine Scientist Environmental Sciences Branch, DBM PRELIMINARY TRIP REPORT--“BII<lN1ATOLL ENVIRONMENTAL An Atomic Energy Commission-Trust Territories environmental survey team of ten scientists and technicians and four Xarshallese natives made radioactivity measurements, took samples of soils, vegetation and animals, and observed environmental conditions at essentially all of the islands in the Bikini Atoll during the period April 23 to i~ay7, 1967. The team consisted of thirteen AEC and AEC contractor personnel and one Trust Territory representative: Tommy McCraw, Radiological Physicist (Division of Operational Safety) and A. B. Joseph, Wmine Scientist (Division of Biology and }Iedicine),AEC Headquarters; Harold Beck and Burt Bennett (!{adiologicalPhysics) of the AEC’S, New York, Health and Safety Laboratory; Francis Tomnovec and Edmond Jones (RadiologicalPhysics) of the U. S. Naval Radiological Defense Laboratory; Edward Held (project leader), Robert Erickson and Jack Tobin (Ecologist, Fisheries Biologist and Anthropologist), University of Washington; Trust Territories personnel: James Hiyane, llajuroDistrict Agriculturalist (Trust Territories); and Transportation to Bikini and around the Atoll was by the XIV Militobi, a% Trust Territory chartered passenger-cargo ship, rechartered by AEC. Thi~ ship (156 feet long, 11 feet draft, 486 gross tons) was manned by a’crew of 21 of mixed nationalities--mainly Micronesia. The ship’s cargo hauling workboats provided ship to shore transportation; these were advantageous in the rough waters at the south edge of the Atoll. The survey team made measurements aod observations on 17 separate land masses; a small island - Arriikan - on the southern rim was bypassed, as were four sand bars (unnamed) on the north rim. Kuadreds of radiation measurements were made, mostly with handheld, betagamma, Geiger-lIullertype survey meters. Gamma spectra were measured several places on the larger islands and on soil samples from islands Buy U.S. Savings Bontis Regdarly on the PayroU SavingJ Plan

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the water was too rough to land the equigment. Some low-level measure- 6 ments were made with the HASL large volume ion-chamber and also the detectors (TLD), a new type of radfation dose device, were placed at likely habitation areas on 13ikiniand Znyu Islands for approximately two weeks. Film bad~es were worn by all survey garty members during the Bikini Atoll surveys. The TLD’s and filn badges were flown baclcto the U.S. for readouts. The only radiation values which are availzble at present are those made with the handheld sllrveyinstruments and these should be considered oaly tentative in that the instruments have not been, / as yet, calibrated for the spectrum of isotopes present or their dose rates. ilanyof the measurements were at the lower limit of sensitivity of the instruments where some uncertainty exists. The three lar~est islands , where most of the natives formerly resided, are Enyu and l?amu. Bikini <S the largest by a factor of 2 to 3 area-wise. Some families also resided on two vr three of the smaller islands on both the northern and southern rims (accordin~ to Jendrik L.). The lowest radiation levels were detected on Enyu, the second lar~est island. Values everywhere in the Island were in the ranse of 0.01 to 0.02 mr/hr, or less, both gamma and beta-gamma at the surface and at 3 feet. 0.04 rm/hr gamma and beta-gamna near the la~oon side beach to a level of approximately 0.25 mr/hr near the center of the island and to 0.02 mr/hr at the ocean beach side. On Namu there WES also a radiation gradient ranging from 0.02 mr/hr at the lagoon beach to 0.35 mr/hr at an interior location to 0.06 mr/hr on the ocean beach side. Other islands on the southern ed~e of the Atoll - Eniirikku and Rukoji - which were downwind of nuclear tests, had levels of about 0.3 mr/hr. The Aomoen-Yurochi chain o~f Islands on the north side had one area where the radiation level was i 0.5 nr/hr. On islands further away from shot sites and not directly dowrurindlevels were more in the range of 0.02 to 0.06 mr/hr. , Gn cost of the smaller islands, within five miles of test points, fragments ferrous and aluminum alloysof metal--- --h~d readings up to 5 mr/hr. Steel reinforcing rods still imbedded in concrete structures facing test points likewise indicated some activity--up to 0.5 mr/hr. iThe gamma spectrometer readings on Bikini and Namu indicated that the gamma activity was largely from isotopes of cobalt and cesium; cesiunt-137 being the major contributor to the total counts. The low activity level on Znyu gave no clear picture of contributing isotopes. Gamma spectrometer readings on soil samples from the smaller southern islands indicate a complex mixture of activation and fission products such as CS-137, CO-60,

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Plant and animal life now exist on all the islands and marine life appears to be abundant in the lagoon and ocean reef waters. The lagoon waters were murky with suspended silt in 1964 and the coral growth was severely inhibited. Such was not the case in 1967--the waters were clear and the coral obviously growing again. Bikini and Enyu are more thiclclyovergrown than in 1964. However, the plant species are mostly of the wild and weedy type, such as scaevola, messerschmidea and dodonea. There were some coconuts and pandanas. Thpre were also some coconuts at the former test camp site on Airukiiji. Coconut crabs were captured on . Bikini and Enyu and on two of the sr.allersouthern rim islands. The k southern rim islands also appeared to be breeding grounds for sea birds such as boobies, frigate birds, nocldies,and terns. The surveY party and ship’s crew captured about a dozen ~reen sea turtles--two of which were in the 300 pound class. A giant clan was taken from the lagoon at Bikini Island; none were found in 1964. The survey was successful in that all work it<ms were done that were planned. There remains much work to be done before a recommendation can be made regarding repatriation. Sanples of soils, plants and animals need to be analyzed for isotopes; the instruments need to be calibrated for the isotope mixtures and levels and then intercalibrated with each other so as to get data as precise as possible; then the radiation data will have to be analyzed in the light of changing human living habits and permissible population dose limits (some levels are higher than guides fbr the population used by Federal Agencies in their health protection activities). It may be that certain areas may have to have time-limited access and that certain local foods may have to be banned (coconut crabs). Some problems of agriculture have straightforward solutions while others will require careful consideration. The islands obviously will sustain plants and a tentative planting,plan has been suggested by the Trust Territories agriculturalist. However, if the isotope data indicate t clean-up operations, how to accomplish it without losing the limited or~anic matter is st~ll a puzzle. In any event, it takes five to seven years from time of planting to get a harvest from a coconut plantation. It may be desirable to initiate at an early date an agricultural res~arch

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Univers!.tyof Washington: USA EC-Division of Biology & Medicine Harold Beck Neil Morriss William A. Bonnet - Area Manager - AEC Hcnolulu Area Office Frank Granich - Kwajalein c Dwight Heine - District Administrator - Trust Territory Robert Johnson - Kwajalein