Northern Marshall Islands Research Articles

Mapping American innocence in the Pacific: Cold War empire, militarization and suburbanization at Kwajalein Atoll

ABSTRACT This article represents a historical and ethnographic reflection on the process of researching an active US military base in the Marshall Islands, while offering analysis of the spatial and cultural forms of suburbanization on the island that emerged during the Cold War. Kwajalein Island served as a support base for the nuclear testing campaign in the Northern Marshall Islands (1946–1958). At that campaign’s conclusion, the island was transformed into a segregated suburban missile installation that remains active today. By tracing my research process on the island, including discoveries of sources that helped me examine the importation of US racial signifiers marking the island’s social order, I offer an analysis on how the physical and cultural construction of this segregated suburban landscape on Kwajalein has helped support an exceptionalist narrative of US imperial innocence in the region.

Cytogenetic and epigenetic aberrations in peripheral lymphocytes of northwest Arkansas Marshallese

Purpose Nuclear weapons testing in the northern Marshall Islands between 1946 and 1958 resulted in ionizing radiation (IR) exposure of the thousands of Marshallese. Furthermore, numerous islands were contaminated by radioactive fallout. Significant increases in cancer and metabolic syndrome incidences have been reported among Marshallese, and potential for further increases looms due to the latency of radiation-induced health effects. The purpose of this study was to investigate the genetic and epigenetic effects of exposure to IR that could be associated with radiation-induced disease among the Northwest Arkansas (NWA) Marshallese. Materials and Methods We performed analysis of chromosomal aberrations and DNA methylation based on residential and exposure history of NWA Marshallese. Results Analysis of chromosomal aberrations demonstrated higher incidence of genetic rearrangements in women with self-reported history of radiation exposure (95% CI: 0.10, 1.22; p=.022). Further clustering of study participants based on their residential history demonstrated that participants who spent substantial amounts of time (≥6 months) in the northern atolls (thus, in the proximity of nuclear tests) before 1980 had more chromosomal aberrations than their peers who lived only in the southern atolls (95% CI: 0.08, −0.95; p=.021), and that this difference was driven by women. A relationship between the time spent in the northern atolls and increase in chromosomal aberrations was observed: 0.31 increase in chromosomal aberrations for every 10 years spent at northern atolls (95% CI: 0.06, 0.57; p=.020). Finally, significant inverse correlations between the chromosomal aberrations and the extent of DNA methylation of four LINE-1 elements L1PA2, L1PA16, L1PREC1, and L1P4B were identified. Conclusions The results of this study provide first evidence of the presence of stable genetic and epigenetic rearrangements in peripheral lymphocytes of NWA Marshallese and warrant further studies to analyze the role of radiation exposure in health disparities experienced by this Pacific Island nation.

Initial Strontium-90 concentrations in ocean sediment from the northern Marshall Islands

The United States detonated 67 nuclear weapons in the Marshall Islands from 1946 to 1958. While there has been significant study of the aftereffects of these explosions over the decades that followed, few values of strontium-90 (90Sr) contamination have been reported. Sediment cores from the Bravo test crater in Bikini Atoll and Lacrosse crater near Runit Island (Enewetak Atoll) were assessed for 90Sr and cesium-137 (137Cs) concentrations, which were found to be measurable in all cores. 90Sr values were found to be roughly consistent across the tested cores. Ratios of 90Sr/137Cs are elevated compared to values measured previously at other sites of weapons testing and nuclear accidents. These findings suggest the need to further investigate 90Sr concentrations in the northern Marshall Islands to assess the safety of current residents in light of the potential for 90Sr conveyance and to provide input regarding resettlement of currently unoccupied islands and atolls.

Isotopic signatures of plutonium and uranium at Bikar atoll, northern Marshall Islands

We present plutonium (Pu) and uranium (U) isotopic fingerprints (or signatures) in environmental samples collected at Bikar Atoll. Bikar is the second –most northern atoll of the Republic of the Marshall Islands, and therefore an important reference point to evaluate the extension of the regional fallout from the Pacific Proving Grounds (PPG) in Bikini and Enewetak Atolls. Previous studies have shown that regional fallout from atmospheric nuclear weapon testing (NWT) in Bikini and Enewetak has resulted in elevated levels of fallout radionuclides in this atoll. In order to optimally interpret the isotopic fingerprints, we compare our results with data obtained in eleven certified reference materials, representing different contamination sources. As well as 238Pu, 239Pu, 240Pu, 241Pu, 238U and 235U, this study also encompasses less commonly reported radionuclides such as 242Pu, 244Pu and 236U. We show the importance of combining numerous fingerprints for improved assessment of the source of a nuclear contamination.In samples from Bikar, Pu and U isotope ratios were found to vary within narrow ranges. Pu and U fingerprints suggest that regional fallout from the Castle Bravo test in March 1954 was the main source of the contamination. This was further confirmed by two different age dating approaches that estimated 1954 as the year of the contamination. We demonstrate that use of an exponential function to approximate the yield of heavy radionuclides in thermonuclear explosions with increasing mass is a valid approach for estimating the age of a contamination. We show that, if sufficient radionuclide activity concentration measurement results with low uncertainties are available, this method is robust.

Assessment of residual radionuclide levels at the Bokak and Bikar Atolls in the northern Marshall Islands

The Bikar and Bokak Atolls, located in the northern Marshall Islands, are extremely isolated and consist of pristine marine and terrestrial ecosystems. Both atolls may have experienced significant radioactive deposition following the nuclear weapon testing conducted at Bikini and Enewetak proving grounds. Here we report activity concentrations of artificial radionuclides (239Pu, 240Pu, 241Pu, 241Am, 137Cs and 90Sr) in marine and terrestrial samples collected from Bikar and Bokak Atolls. Artificial radionuclides in soil from the Majuro Atoll are also reported and form a radiological baseline against which the levels at the other atolls can be compared. We observed low levels of artificial radionuclides in soil from Majuro and Bokak, but significantly higher levels in soil from Bikar. The residual radioactivity in the Bikar environment is comparable to the levels previously reported for other nearby atolls, including Taka and Utrik, but lower than for Rongerik, Rongelap, Bikini and Enewetak. An analysis of 240Pu/239Pu isotope ratios and estimations of the dates of contamination from 241Am/241Pu activity ratios both indicated that the Bikar Atoll was contaminated mainly by radioactive fallout from the Castle Bravo test in 1954. We compare the results of our measurements at Bikar and Bokak to data from other atolls in the Marshall Islands and to regions of the world affected by both global and regional fallout from atmospheric nuclear weapons testing and nuclear accidents.

Reptiles of the Northern Marshall Islands

Fifteen species of reptiles are recorded from among the nine northernmost atolls in the Republic of the Marshall Islands (RMI): 3 sea turtles, 10 lizards (3 geckos, 6 skinks, 1 monitor lizard) and 1 typhlopid snake. None is endemic to the Marshalls and all are widely distributed in Micronesia and, in many cases, well beyond. The Common House Gecko, Hemidactylus frenatus, Mariana Monitor, Varanus tsukamotoi, and Brahminy Blindsnake, Indotyphlops braminus, probably were introduced in recent times, but to what extent the other species arrived by natural dispersal, or, alternatively, by human-assisted transport at various times since the initial settlement of the islands about 2,000 years ago, is unknown. The 126 specimens of lizards collected from among eight of the atolls during March/April 2019 include the first records of terrestrial reptiles from Ailinginae Atoll, and the first records of Hemidactylus frenatus from Rongelap, Bokak, and Utirik Atolls, Gehyra oceanica from Rongelap and Taka Atolls, and Lepidodactylus lugubris from Utirik Atoll. Numerous other distribution records obtained from online databases—with the vast majority previously unreported in the literature—are included along with the earliest collection date in the RMI of H. frenatus and a revised early collection date for I. braminus.

In situ measurement of cesium-137 contamination in fruits from the northern Marshall Islands

Radioactive contamination of fruits in the northern Marshall Islands, resulting from the US nuclear weapons testing program in the 1940s and 1950s, is still a human health concern, in particular pertaining to island population resettlement and the economic benefit from farming. Over 200 fruits, primarily coconuts and pandanus, were collected on 11 islands from four atolls in the northern Marshall Islands in 2017. The energy spectra from nuclear gamma decays were measured on a research vessel for each fruit in situ. From these recordings, the level of cesium-137 (137Cs) contamination was determined for individual fruits. Comparisons of the results are made to past studies and international food safety standards. There is a broad distribution of values, ranging from below detectable radiation levels to relatively high levels; safety concerns are largest for Bikini Island. A noticeable fraction of fruits from Bikini have significantly higher levels of 137Cs contamination compared with those from all other measured islands.

Background gamma radiation and soil activity measurements in the northern Marshall Islands

We report on measurements of external gamma radiation on 9 islands in 4 atolls in the northern Marshall Islands, all of which were affected by the US nuclear testing program from 1946 to 1958 (Enjebi, Ikuren, and Japtan in Enewetak Atoll; Bikini and Enyu in Bikini Atoll; Naen in Rongelap Atoll; and Aon, Elluk, and Utirik in Utirik Atoll). We also report americium-241, cesium-137, plutonium-238, and plutonium-239,240 activity concentrations in the soil samples for 11 islands in 4 northern atolls (Enewetak, Japtan, Medren, and Runit in Enewetak Atoll; Bikini and Enyu in Bikini Atoll; Naen and Rongelap in Rongelap Atoll; and Aon, Elluk, and Utirik in Utirik Atoll) and from Majuro Island, Majuro Atoll in the southern Marshall Islands. Our results show low external gamma radiation levels on some islands in the Enewetak Atoll and Utirik Atoll, and elevated levels on Enjebi Island in the Enewetak Atoll, on Bikini Atoll, and on Naen Island in the Rongelap Atoll. We perform ordinary kriging on external gamma radiation measurements to provide interpolated maps. We find that radionuclides are absent from all Majuro soil samples, and that they are present at highest activity concentrations in samples from Runit and Enjebi islands (Enewetak Atoll), Bikini Island (Bikini Atoll), and Naen Island (Rongelap Atoll). We contextualize all results by making comparisons between islands and to various standards, as well as to regions of the world affected by nuclear accidents. We also discuss implications for informed decision-making by the Marshallese and local atoll governments and their people on issues pertaining to island resettlement.

Measurement of background gamma radiation in the northern Marshall Islands

We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <<0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered.

Characterization of Coral Communities at Wake Atoll in the Remote Central Pacific Ocean

Little published or unpublished information exists concerning he benthic community structure or coral fauna at Wake Atoll in the Central Pacific. Here, we apply multivariate statistical analyses to data acquired in 2005 from several complementary survey methods that operate at different scales of spatial and taxonomic resolution to characterize the coral communities in the fore-reef habitat, which is further stratified by geographic sector and depth zone. Both broad-scale towed-diver surveys and site-specific photoquadrat surveys revealed high dissimilarity in overall benthic composition between the northeast and southwest sectors. Coral cover in the northeast sector is more than 2.5 times greater than in the southwest sector; encrusting and massive growth forms dominate in the northeast sector while encrusting and digitate growth forms dominate in the southwest sector. Coral cover and colony abundances are less dominated by a few key genera in the northeast than in the southwest sector, though the genera Montipora, Pocillopora, and Favia are the most numerically abundant taxa in both sectors. Octocorals account for more than 25% of the total coral cover in the northeast sector but less than 5% of the total coral cover in the southwest sector. The deep northeast stratum showed among the highest diversity of growth forms as well as the highest total coral cover, octocoral cover, and coralline algal cover. We provide a list of 101 anthozoan and hydrozoan corals observed at Wake Atoll during survey activities since the year 1979. Five scleractinian species at Wake are on the IUCN Red List of Threatened Species™. The 80 taxa with well-established species names contain components from the Mariana Islands, northern Marshall Islands, and Hawaiian Islands, but show the closest resemblance to the Mariana Islands. Our spatially widespread surveys that generate independent metrics of benthic cover and coral abundance collectively provide the most comprehensive description of coral communities at Wake Atoll produced to date and also provide an important record by which to monitor the response of this community to changing ocean conditions.

Distribution of cesium-137 in tree crop products collected from residence islands impacted by the U.S. nuclear test program in the northern Marshall Islands

The Marshall Islands Program at the Lawrence Livermore National Laboratory has completed a series of radiological surveys at Bikini, Rongelap, Utrōk, and Enewetak Atolls in the Marshall Islands designed to take a representative sample of food supplies with emphasis on determining 137Cs activity concentrations in common food plants. Coconuts (Cocos nucifera L.) are the most common and abundant food plant, and provided a common sample type to characterize the level and variability of activity concentrations of 137Cs in plant foods collected from different islands and atolls. Other dominant food types included Pandanus (Pandanus spp.) and breadfruit (Actocarpus spp.). In general, the activity concentration of 137Cs in food plants was found to decrease significantly between the main residence islands on Bikini, Rongelap, Utrōk, and Enewetak Atolls. The mean activity concentration of 137Cs measured in drinking coconut meat and juice was 0.72 (95 % CI 0.68–0.77) and 0.34 (95 % CI 0.30–0.38) Bq g−1, respectively, on Bikini Island; 0.019 (95 % CI 0.017–0.021) and 0.027 (95 % CI 0.023–0.031) Bq g−1, respectively, on Rongelap Island; 0.010 (95 % CI 0.007–0.013) and 0.007 (95 % CI 0.004–0.009) Bq g−1, respectively, on Utrōk Island; and 0.002 (95 % CI 0.0013–0.0024) and 0.002 (95 % CI 0.001–0.0025) Bq g−1, respectively, on Enewetak Island. High levels of variability are reported across all islands. These results will be used to improve the accuracy and reliability of predictive dose assessments, help characterize levels of uncertainty and variability in activity concentrations of fallout radionuclides in plant foods, and allow atoll communities to make informed decisions about resettlement and possible options for cleanup and rehabilitation of islands and atolls.

Website application for calculating cesium-137 ingestion doses from consumption of locally grown foods in the Marshall Islands

Fallout deposition from the US nuclear weapons test program at Bikini and Enewetak Atolls (1946–1958) resulted in widespread nuclear fallout contamination of the northern Marshall Islands. About 85–90 % of the nuclear test-related dose delivered to resident populations is derived from ingestion of cesium-137 (137Cs) contained in locally grown tree-crop food products. The Lawrence Livermore National Laboratory has developed a series of interactive internet applications to provide the public with an open access platform to learn more about radiological conditions in the Marshall Islands. The ingestion dose calculator application described here is one such feature whereby users can calculate hypothetical ingestion doses from 137Cs based on interactive user input matched to environmental data on the activity concentration of 137Cs contained in food plants such as coconut, breadfruit, Pandanus, and arrowroot. Users are asked to enter a date, an island and atoll location, a plant food type, and a daily intake amount (highlighted by the number of portions eaten per day in estimated gram equivalents). The application computes the user daily dose and the user equivalent annualized dose, and then compares the results with default settings based on dietary models developed for the Marshall Islands from independent dietary surveys. The default diets are based on a local plus imported food diet (or IA diet model) and an imported foods unavailable diet (or IUA diet model). Environmental data are decay corrected to the date entered by the user using an effective half-life of 137Cs of 8.5 years (http://marshallislands.llnl.gov).

Separation of uranium and plutonium isotopes for measurement by multi collector inductively coupled plasma mass spectroscopy

Uranium (U) and plutonium (Pu) isotopes in coral soils, contaminated by nuclear weapons testing in the northern Marshall Islands, were isolated by ion-exchange chromatography and analyzed by mass spectrometry. The soil samples were spiked with 233U and 242Pu tracers, dissolved in minerals acids, and U and Pu isotopes isolated and purified on commercially available ion-exchange columns. The ion-exchange technique employed a TEVA® column coupled to a UTEVA® column. U and Pu isotope fractions were then further isolated using separate elution schemes, and the purified fractions containing U and Pu isotopes analyzed sequentially using multi-collector inductively coupled plasma mass spectrometer (MCICP-MS). High precision measurements of 234U/235U, 238U/235U, 236U/235U, and 240Pu/239Pu in soil samples were attained using the described methodology and instrumentation, and provide a basis for conducting more detailed assessments of the behavior and transfer of uranium and plutonium in the environment.

Frequency distribution, isotopic composition and physical characterization of plutonium-bearing particles from the Fig-Quince zone on Runit Island, Enewetak Atoll

Runit Island on Enewetak Atoll was very heavily impacted by the U.S. nuclear testing campaign in the northern Marshall Islands (1946–58). The primary source of contamination on Runit Island was the 1958 Quince safety test where a large quantity of device plutonium (Pu) was scattered over the area near the GZ. A second low-yield device was detonated on the same site 10 days later, further disturbing the soil and leaving behind a very heterogeneous pattern of contamination including milligram-size particles of plutonium. A limited cleanup of the Fig-Quince zone was carried out in 1979. During this period, the effectiveness of the cleanup operations was primarily evaluated on the basis of bulk soil concentration data with little consideration given to the heterogeneity and long-term material-, biological-, and environmental-specific impacts of residual high activity (hot) particle contamination. The aim of the present study was twofold; (i) to characterize the levels and distribution of residual contamination in the Fig-Quince zone, and (ii) to develop pertinent data on the frequency distribution, elemental and isotopic composition, and physico-chemical properties of hot particles isolated from surface soils from Fig-Quince with a view towards providing recommendations on the future management and possible cleanup of the site. Today, Runit Island remains under an administrative quarantine.

Complementing PABITRA High-Island Studies by Examining Terrestrial Plant Diversity on Atolls

The Pacific-Asia Biodiversity Transect (PABITRA) studies are based on a network of high-island biodiversity sites. These sites are structurally and historically complex. The majority of Pacific islands, in contrast, are low atolls with a common and simple flora and structure. As a result, atolls may serve as controls that may provide a way to assess impact of the upland high-island ecosystems on coastal regions of Pacific islands. Atoll studies can complement the PABITRA network because the gateway sites are near each other or separated from one another by one or more atolls. Such an addition will enhance interpretation of high-island ecosystems and their coastal zones because ecosystem surveys can be conducted quickly and accurately in atoll environments. We present results from quantitative studies of plant diversity from seven islets at Ailinginae Atoll in the northern Marshall Islands and discuss the value of this methodology as a way to enhance interpretation of the PABITRA data.

On the Margins of Sustainability, Prehistoric Settlement or Utrok Atoll, Northern Marshall Islands (review)

Reviewed by: On the Margins of Sustainability, Prehistoric Settlement of Utrok Atoll, Northern Marshall Islands Rosalind L. Hunter-Anderson On the Margins of Sustainability, Prehistoric Settlement of Utrok Atoll, Northern Marshall Islands. Marshall I. Weisler. BAR International Series 967, Oxford: Archaeopress, 2001. xiii + 144 pp., illustrations, maps, bibliography, appendices. $42.00. ISBN 1-84171-254-X. On the Margins of Sustainability is a well-produced and important addition to the growing literature on the archaeology of small tropical coral islands. The new facts, [End Page 158] collected systematically and reported in considerable detail, are especially welcome given the general paucity of published information on Micronesian archaeology. (The work could have used a thorough copy editing to catch the typos and verb/person mismatches, however.) In eight chapters and three appendices, and illustrated with numerous maps, drawings, and black and white photographs by the author, the monograph reports the results of surveys and excavations conducted by Weisler and Marshallese colleagues in seven islets of Utrok Atoll in the northern Marshalls. The Utrok research is part of a more comprehensive project of archaeological documentation instigated by the author some ten years ago. This project has included surveys and excavations at Epoon, Wujae, and Maloelap Atolls in addition to Utrok. Students at the University of Otago participated in the initial processing and subsequent laboratory analyses of the data, resulting so far in three Master's theses, the present report, and publications elsewhere by Weisler. The fieldwork at Utrok Atoll was carried out when Weisler was Chief Archaeologist for the Republic of the Marshall Islands from 1993-1995 and subsequently. From having lived in the islands for several years, as well as having worked in a variety of settings in the tropical Pacific, he has become attuned to the ethnographic and geographic realities of small islands. For example his comments about current fishing practices and their relation to marine habitat attributes and current Marshallese subsistence options enhance the exposition beyond what researchers with less experience and cultural sensitivity might have produced. The "long-term goal" of the project to which the Utrok results contribute is, "to understand the regional variation of Marshall Islands archaeology and to provide a basic culture-history for the archipelago" (p. xi). Weisler suggests that a key factor conditioning regional variation here is the north-south rainfall gradient, with Utrok at the dry northern extreme. The other atolls investigated during the project are situated southward along this gradient. Another environmental constraint noted by Weisler is islet size. This factor determines the presence of a fresh water lens and clearly affects the potential for sustained occupation of a given islet. Another factor considered in Weisler's quest for understanding regional variation is sea level, notably the lower levels after c. 650 B.P. (citing Nunn 1998) which may have affected productivity of aroid pits putatively created before this time at Utrok. The dual orientation, toward geographic factors as causally linked to cultural variations and toward culture history as an ultimate goal is indicated in Chapter 1 and further elaborated upon in the last chapter, Synthesis. Under the research design heading in Chapter 1, several "issues in atoll archaeology" are listed and briefly discussed: origins, chronology, sea level change and islet development, material culture, terrestrial production, and landscape change. These topical discussions provide interpretive contexts for the data to come, based on past and present research orientations in Pacific archaeology. Thus the research program was aimed at filling gaps in mostly predefined problem areas. Chapter 2, The Archaeological Landscape, contains information about current land use patterns in the Marshalls generally and at Utrok Atoll in particular, as well as results of archaeological surveys within the atoll, at Pike, Allok, Bikrak, Nalap, Utrok, and Aon Islets. The photographs and other illustrations are effective in conveying some of the pertinent details observed during the surveys. Chapter 3, Excavation of Habitation Sites, describes field methods and stratigraphic details about the excavation units by islet and site (five sites, seven islets). Plans showing the location of the excavations are included for each islet. The large islet of Utrok, with the most extensive habitation area in the atoll, was investigated intensively. At Site 1, a radiocarbon date...

The effective and environmental half-life of 137Cs at Coral Islands at the former US nuclear test site

The United States (US) conducted nuclear weapons testing from 1946 to 1958 at Bikini and Enewetak Atolls in the northern Marshall Islands. Based on previous detailed dose assessments for Bikini, Enewetak, Rongelap, and Utirik Atolls over a period of 28 years, cesium-137 ( 137Cs) at Bikini Atoll contributes about 85–89% of the total estimated dose through the terrestrial food chain as a result of uptake of 137Cs by food crops. The estimated integral 30, 50, and 70-year doses were based on the radiological decay of 137Cs (30-year half-life) and other radionuclides. However, there is a continuing inventory of 137Cs and 90Sr in the fresh water portion of the groundwater at all contaminated atolls even though the turnover rate of the fresh groundwater is about 5 years. This is evidence that a portion of the soluble fraction of 137Cs and 90Sr inventory in the soil is lost by transport to groundwater when rainfall is heavy enough to cause recharge of the lens, resulting in loss of 137Cs from the soil column and root zone of the plants. This loss is in addition to that caused by radioactive decay. The effective rate of loss was determined by two methods: (1) indirectly, from time-dependent studies of the 137Cs concentration in leaves of Pisonia grandis, Guettarda specosia, Tournefortia argentea (also called Messerschmidia), Scaevola taccada, and fruit from Pandanus and coconut trees ( Cocos nucifera L.), and (2) more directly, by evaluating the 137Cs/ 90Sr ratios at Bikini Atoll. The mean (and its lower and upper 95% confidence limits) for effective half-life and for environmental-loss half-life (ELH) based on all the trees studied on Rongelap, Bikini, and Enewetak Atolls are 8.5 years (8.0 years, 9.8 years), and 12 years (11 years, 15 years), respectively. The ELH based on the 137Cs/ 90Sr ratios in soil in 1987 relative to the 137Cs/ 90Sr ratios at the time of deposition in 1954 is less than 17 years. The magnitude of the decrease below 17 years depends on the ELH for 90Sr that is currently unknown, but some loss of 90Sr does occur along with 137Cs. If the 15-year upper 95% confidence limit on ELH (corresponding to an effective half-life of 9.8 years) is incorporated into dose calculations projected over periods of 30, 50, or 70 years, then corresponding integral doses are 58, 46 and 41%, respectively, of those previously calculated based solely on radiological decay of 137Cs.

Life on the edge: prehistoric settlement and economy on Utrōk Atoll, northern Marshall Islands

AbstractThe prehistoric settlement pattern and economy of Utrōk Atoll, situated near the northern limit of permanently‐inhabited atolls in the Marshall Islands, is described and interpreted from a complete intensive survey and excavations totalling 64 m2 (70.45 m3). Sites range from the most expansive, 25 hectare habitation and horticultural system on the largest islet, to smaller, temporarily‐occupied habitations situated on diminutive islets. A suite of 16 radiocarbon age determinations suggests human occupation of the atoll by the first few centuries AD (Beta‐103903). Four additional dating samples, collected from emerged beachrock, determined when the islets adjusted shape in response to changing sea levels and coastal processes.Some 173 prehistoric tools and ornaments included 39 shell adzes, pumice abraders, pearl shell scrapers, pounders and hammerstones, a trolling lure point, a single piece fishhook point and ornaments such as Conus shell rings, Spondylus beads and disks, pendants and a small drilled whale tooth.Of the 13,545 bones, 88.6% were of fish, mostly inshore taxa, with dog (Canis familiaris), Pacific rat (Rattus exulans), sea turtle (cf. Chelonia mydas), lizard and bird (Puffinus, Phaethon, Sula, Fregata, Egretta and Heteroscelus), as well as three human burials. Some 45.7 kg of shellfish representing 34 families was dominated by bivalves (67%) of mostly Tridacnidae. The Bullmouth helmet, Cypraecassis rufa, was extirpated as a result of human predation, although the archaeological evidence suggests that low human populations on this relatively dry atoll had little noticeable impact on the marine ecosystem, while the terrestrial landscape was markedly altered.

Measurement of 240Pu/ 239Pu isotopic ratios in soils from the Marshall Islands using ICP-MS

Nuclear weapons tests conducted by the United States in the Marshall Islands produced significant quantities of regional or tropospheric fallout contamination. Here we report on some preliminary inductively coupled plasma-mass spectrometry (ICP-MS) measurements of plutonium isolated from seven composite soil samples collected from Bikini, Enewetak and Rongelap Atolls in the northern Marshall Islands. These data show that 240Pu/ 239Pu isotopic signatures in surface soils from the Marshall Island vary significantly and could potentially be used to help quantify the range and extent of fallout deposition (and associated impacts) from specific weapons tests. 137Cs and 60Co were also determined on the same set of soil samples for comparative purposes.

The Decolonisation of the Pacific Islands

At the end of the Second World War, the islands of Polynesia, Melanesia and Micronesia were all under foreign control. The Netherlands retained West New Guinea even while control of the rest of the Dutch East Indies slipped away, while on the other side of the South Pacific, Chile held Easter Island. Pitcairn, the Gilbert and Ellice Islands, Fiji and the Solomon Islands comprised Britain's Oceanic empire, in addition to informal overlordship of Tonga. France claimed New Caledonia, the French Establishments in Oceania (soon renamed French Polynesia) and Wallis and Futuna. The New Hebrides remained an Anglo-French condominium; Britain, Australia and New Zealand jointly administered Nauru. The United States' territories included older possessions – the Hawaiian islands, American Samoa and Guam – and the former Japanese colonies of the Northern Marianas, Mar-shall Islands and Caroline Islands administered as a United Nations trust territory. Australia controlled Papua and New Guinea (PNG), as well as islands in the Torres Strait and Norfolk Island; New Zealand had Western Samoa, the Cook Islands, Niue and Tokelau. No island group in Oceania, other than New Zealand, was independent.