Bikini Atoll Research Articles

Resuspension studies in the Marshall Islands.

The contribution of inhalation exposure to the total dose for residents of the Marshall Islands was monitored at occasions of opportunity on several islands in the Bikini and Enewetak Atolls. To determine the long-term potential for inhalation exposure, and to understand the mechanisms of redistribution and personal exposure, additional investigations were undertaken on Bikini Island under modified and controlled conditions. Experiments were conducted to provide key parameters for the assessment of inhalation exposure from plutonium-contaminated dust aerosols: characterization of the contribution of plutonium in soil-borne aerosols as compared to sea spray and organic aerosols, determination of plutonium resuspension rates as measured by the meteorological flux-gradient method during extreme conditions of a bare-soil vs. a stabilized surface, determination of the approximate individual exposures to resuspended plutonium by traffic, and studies of exposures to individuals in different occupational environments simulated by personal air sampling of workers assigned to a variety of tasks. Enhancement factors (defined as ratios of the plutonium-activity of suspended aerosols relative to the plutonium-activity of the soil) were determined to be less than 1 (typically 0.4 to 0.7) in the undisturbed, vegetated areas, but greater than 1 (as high as 3) for the case studies of disturbed bare soil, roadside travel, and for occupational duties in fields and in and around houses.

University of Washington's radioecological studies in the Marshall Islands, 1946-1977.

Since 1946, personnel from the School of Fisheries, University of Washington (Applied Fisheries Laboratory, 1943-1958; Laboratory of Radiation Biology, 1958-1967; and Laboratory of Radiation Ecology, since 1967), have studied the effects of nuclear detonations and the ensuing radioactivity on the marine and terrestrial environments throughout the Central Pacific. A collection of reports and publications about these activities plus a collection of several thousand samples from these periods are kept at the School of Fisheries. General findings from the surveys show that (1) fission products were prevalent in organisms of the terrestrial environment whereas activation products were prevalent in marine organisms; (2) the best biological indicators of fallout radionuclides by environments were (a) terrestrial-coconuts, land crabs; (b) reef-algae, invertebrates; and (c) marine-plankton, fish. Studies of plutonium and americium in Bikini Atoll showed that during 1971-1977 the highest concentrations of 241Am, 2.85 Bq g(-1) (77 pCi g(-1)) and 239,240Pu, 4.44 Bq g(-1) (120 pCi g(-1)), in surface sediments were found in the northwest part of the lagoon. The concentrations in the bomb craters were substantially lower than these values. Concentrations of soluble and particulate plutonium and americium in surface and deep water samples showed distributions similar to the sediment samples. That is, the highest concentration of these radionuclides in the water column were at locations with highest sediment concentration. Continuous circulation of water in the lagoon and exchange of water with open ocean resulted in removal of 111 G Bq y(-1) (3 Ci y(-1)) 241Am and 222 G Bq y(-1) (6 Ci y(-1)) 239,240Pu into the North Equatorial Current. A summary of the surveys, findings, and the historical role of the Laboratory in radioecological studies of the Marshall Islands are presented.

Ghost fleet: the sunken ships of Bikini Atoll

In 1946, the United States began a series of nuclear tests on Bikini Atoll to determine the impact of atomic bombs. Delgado, a noted marine archaeologist with the National Park Service, visited Bikini in the late 1980s to explore and document the condition of the sunken ships. His work is more than an archaeological study; it is the history of the nuclear age. This book chronicles the development of the bomb, its deployment in Japan, the preparations for the tests, the attempted clean-up afterward, and the beginning of the Cold War.

ARTIFICIAL RADIOACTIVE NUCLIIDES IN MARINE ENVIRONMENT: DETRIMENTAL TO LIFE

The object of this paper is to know what are the artificial radioactive nucliides in marine environment, where and what are the sources of their products, what are their effects to the health of marine and land populations. With this view in mind we shall discuss the large‐scale production of man‐made artificial nucliides that have been poured into the oceans since about the middle of the present century. The first significant release of radioactive nucliides to the marine environment began in late 1944 in USA with the discharge of effluent from her reactors at Hanford Atomic Plant to the North East Pacific Ocean via Columbia River. In the following year, July 1945, an atom bomb was tested successfully and the detonation of two more tests of atom bombs at Bikini Atoll (Pritchard et al, 1971; Seymour, 1971) introduced enough amount of radioactive nucliides into the North Equatorial Current System of the Pacific Ocean.

"Only as Dust in the Face of the Wind": An Analysis of the BRAVO Nuclear Incident in the Pacific, 1954

On the morning of 1 March 1954, the United States detonated a ther monuclear weapon named BRAVO at its proving grounds on the Bi kini Atoll in the Marshall Islands.1 Within one minute, this bomb produced a huge fireball, created a massive crater in the coral reef, and stripped the nearby islands of all vegetation. The energy released by the explosion was equivalent to 15 million tons of TNT.2 BRAVO is significant to the history of American-East Asian rela tions for a number of reasons. First, it was the largest thermonuclear test ever carried out by the United States.3 One thousand times more

237Np in hemp-palm leaves of Bontenchiku for fishing gear used by the Fifth Fukuryu-Maru: 40 years after "Bravo".

The alpha radioactive components in the Hemp-palm of Bontenchiku were determined with emphasis on the measurement low-level 237Np by alpha-ray spectrometry after chemical separation. Bontenchiku is a kind of fishing gear for long-line fishing used by the Fifth Fukuryu-Maru (Lucky Dragon). This gear was exposed to fallout from the second thermonuclear test explosion (Bravo) at Bikini Atoll in March 1954. The 237Np content in the Bontenchiku sample was determined to be 11.5 +/- 0.8 mBq g(-1), with an activity ratio of 237Np:239,240Pu and an atom ratio of 237Np:239Pu estimated to be (2.2 +/- 0.2) x 10(-3) and 0.42 +/- 0.04, respectively. The data showed the existence of a chain reaction of 238U and its ratio to be 237Np:239Pu, as well as the presence of 237U at the time of fallout from Bravo event in March 1954.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Assessment of plutonium exposures in Rongelap and Utirik populations by fission track analysis of urine

A nuclear device, code-named Bravo, detonated at Bikini Atoll at 6:45 a.m. on 1 March 1954, unexpectedly released a large amount of radioactivity. Over 40 years after this incident, the study of its impact on the radiological health and environmental safety of the residents of Rongelap and Utirik Atolls continues. In 1987, researchers at Brookhaven National Laboratory established a fission track analysis (FTA)_method for low-level 239Pu urinalysis. Two years later, a new shipboard protocol was developed for collecting 34-h radiologically clean urine samples. The purpose of this paper is to update information on the FTA method for measuring low-levels of plutonium, and to summarize results on the distribution of 239Pu in the populations of Rongelap and Utirik between 1981–1991. Plutonium detection levels (99% confidence level) in these samples were 2–3 μBq, which is equivalent to 0.2–0.3 mSv effective dose equivalent (EDE) to age 70 for Marshallese. The latest 1991 FTA data indicate average EDE of 0.62 mSv and 1.6 mSv for the people of Rongelap and Utirik, respectively, which both are the highest values since 1988.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Operation Crossroads: The Atomic Tests at Bikini Atoll.

Operation Crossroads: The Atomic Tests at Bikini Atoll. Jonathan M. Weisgall

<i>Operation Crossroads: The Atomic Tests at Bikini Atoll</i>. Jonathan M. Weisgall

Operation Crossroads: the atomic tests at Bikini Atoll

Provides a study of the 1946 nuclear tests at Bikini Atoll, by an attorney for displaced atoll inhabitants seeking to return home.

Bikini and Enewetak marshallese: Their atolls and nuclear weapons testing

Abstract Following the end of World War H, the U.S. Government decided to commence nuclear weapons testing and consequently searched for a suitable test site. Bikini and Enewetak Atolls in the Marshall Islands were selected for various reasons discussed in this manuscript. Sixty‐six nuclear devices of various types were detonated from 1945 through mid‐1958 at these atolls. During this period and for an extended period thereafter, extensive endeavors to rehabilitate these atolls occurred. In addition to physical rehabilitation, scientists were involved in basic investigations on the cycling of radionuclides and the effects of ionizing radiation on the atoll environment. Further, a limited number of observations were made on the cultural impacts of removal and possible return of the Bikini and Enewetak Marshallese to their home atolls. The extensive but obscure literature as well as unfamiliarity by many people of the health aspects of ionizing radiation and fundamentals of radiation ecology encouraged the ...

ADSORPTION AND DESORPTION KINETICS OF CESIUM IN AN ORGANIC MATTER-RICH SOIL SATURATED WITH DIFFERENT CATIONS

The fallout from nuclear weapons tests conducted on Bikini Atoll Island in 1954 resulted in contamination of soil with Cesium 137. To develop effective regimes for decontaminating the Bikini Atoll soil, the exchange of Cs for K, Na, and other cations on the soil must be understood. Samples of soils made homoionic with K, Na, or Ca were reacted with solutions containing Cs ions, and the quantities of Cs sorbed and the rates of exchange were measured. The samples were then reacted with solutions containing K, Na, or Ca, and the quantities of Cs desorbed and the rates of exchange were again measured. Samples made homoionic with Na had a greater ion exchange capacity than samples made homoionic with K, and, in both cases, the ion exchange capacity increased with the organic matter content of the soil. For samples pretreated with Ca, the ion exchange capacity is not related in a simple way to the organic matter content. The kinetics were assessed by plotting the rate of exchange vs. the time and vs. the quantity exchanged. A first-order equation was obeyed during most of the run in Cs desorption experiments and during a limited part of the run in Csmore » adsorption experiments. An increase in the rate of Cs exchange was observed at the beginning of the experiments especially for Cs adsorption. This increase is presumably due to an increase of the ionic strength of the liquid phase during the exchange process. 33 refs., 9 figs., 2 tabs.« less

Uncertainties in predicted radionuclide body burdens and doses from discrete stochastic source terms.

Expressions are derived in three cases for the expectation and uncertainty of body burdens and doses calculated from a linear model of environmental transport and human metabolism in terms of expectation and uncertainty in inputs of discrete, stochastic random variables. Three cases are compared to determine the relationship of the expectations and uncertainties under varying assumptions. In the constant input case, the input is selected randomly at the outset of the simulation period [O,T] from the distribution to which the population is exposed and then is held constant throughout [O,T]. In the two time-varying cases, random and autoregressive, it was assumed that N discrete stochastic exposures to the input were made uncorrelated and partially correlated, respectively. Each exposure was constant during each time interval of length T/N. The expectation values of the body burdens and doses in the constant input case were identical to those in the random case and the autoregressive cases for stationary inputs. The uncertainties of the body burdens and the doses in the constant input case were identical in the limit of rapid metabolism to those of the random case and the autoregressive cases for stationary inputs. In the limit of slow metabolism, the uncertainties of the body burdens and the doses in the constant input case were N1/2 and (3N/4)1/2, respectively, greater than those in the random case and were ((1 + alpha)/[(1 - alpha)N])1/2 and (4(1 + alpha)/[3(1 - alpha)N])1/2, respectively, greater than those in the autoregressive case for stationary inputs and autocorrelation coefficient alpha. That is, increasing the number of sampling periods decreases the uncertainty and increasing the autocorrelation increases the uncertainty. In an example application for ingestion of 137Cs at Bikini Island, a weak form of both slow and rapid metabolism limits apply and give the result that the uncertainty of the body burden in the constant input case is 18 times greater than the random case. For alpha = 0.5, the uncertainty of the body burden in the autoregressive case is 1.7 times greater than the random case. The smooth transition of the autoregressive case from the random case to the constant input case is shown as alpha increases from 0 (random) to 1 (constant).

The effect of potassium on the uptake of 137Cs in food crops grown on coral soils: coconut at Bikini Atoll.

The soils of Bikini Atoll (11 degrees 35'N, 165 degrees 25'E) were contaminated by fallout from a thermonuclear explosion in 1954. Today, in the absence of any treatment, intake of 137Cs via the terrestrial food chain could account for 70% of the radiological dose received by a returning population. Therefore, we examined the effectiveness of potassium applications, alone and combined with nitrogen and phosphorus, in reducing 137Cs uptake by coconut (Cocos nucifera L.), a major food crop. Mean pretreatment concentrations of 137Cs in "drinking-nut" meat of approximately 17-y palms ranged from approximately 0.5 to 7.0 kBq kg-1 (approximately 14 to 190 pCi g-1) (wet mass) in the seven primary experiments reported. These values were reduced to approximately 0.06 to approximately 1.0 kBq kg-1 (approximately 1.6 to approximately 27 pCi g-1) following soil additions of potassium-chloride at rates from 670 to 6270 kg potassium ha-1. Major reductions were complete within 9-12 mo after single large applications and persisted for at least 3 y. Proportional reductions in associated drinking-nut fluid and in mature "copra nut" meat from the same palm also occurred. Comparable but shorter-lived reductions occurred in grass and herbaceous species beneath the palms. A combined nitrogen-phosphorus treatment had no additive effect in the presence of potassium but, by itself, reduced plant uptake by about 50%. The persistence of this effect suggested that phosphorus alone was the major factor. Periodic addictions of potassium at rates of approximately 1000 kg ha-1 would provide a feasible and highly effective means of reducing 137Cs in coconut food products.

Late medical consequences of exposure to radioactive fallout

Data collected by the Brookhaven Medical Program on the late medical consequences of the exposure to radioactive fallout originated from the detonation of a thermonuclear device on Bikini atoll in Marshall Islands are discussed.

Somatic mutation frequencies in the stamen hairs of Tradescantia grown in soil samples from the Bikini Island.

Somatic pink mutation frequencies in the stamen hairs of Tradescantia BNL 02 clone grown for 76 days in two soil samples taken from the Bikini Island (where a hydrogen bomb explosion test had been conducted in 1954) were investigated. A significantly high mutation frequency (2.58 +/- 0.17 pink mutant events per 10(3) hairs or 1.34 +/- 0.09 pink mutant events per 10(4) hair-cell divisions) was observed for the plant grown in one of the two Bikini soil samples, as compared to the control plants (1.70 +/- 0.14 or 0.88 +/- 0.07, respectively) grown in the field soil of Saitama University. The soil sample which caused the significant increase in mutation frequency contained 6,880 +/- 330 mBq/g 137Cs, 62.5 +/- 4.4 mBq/g 60Co, and some other nuclides; a 150 microR/hr exposure rate being measured on the surface of the soil sample. The effective cumulative external exposures measured for the inflorescences of the plant grown in this soil sample averaged at most 60.8 mR, being too small to explain the significant elevation in mutation frequency observed. On the other hand, internal exposure due to uptake of radioactive nuclides was estimated to be 125 mrad (1.25 mGy) as an accumulated effective dose, mainly based on a gamma-spectrometrical analysis. However, it seemed highly likely that this value of internal exposure was a considerable underestimate, and the internal exposure was considered to be more significant than the external exposure.

The birds of Bikini Atoll, Marshall Islands: May 1986

The birds of Bikini Atoll, Marshall Islands: May 1986

The birds of Bikini Atoll, Marshall Islands: May 1986

The birds of Bikini Atoll, Marshall Islands: May 1986