Regional Fallout Research Articles

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.

High-precision measurement of U-Pu-Np-Am concentrations and isotope ratios in environmental reference materials by mass spectrometry

We report results of precise and sensitive mass spectrometric measurements of uranium, plutonium, neptunium, and americium concentrations and isotope ratios in a variety of environmental reference materials. Most of our work has been done on NIST SRM 4350b, River Sediment, but we also present results for NIST SRM 4354, Lake Sediment; NIST SRMs 4355 and 4355a, Peruvian Soil; NIST SRM 4357, Ocean Sediment; NIST SRM 1648a, Urban Particulate Material; NIST SRM 1649b, Urban Dust; IAEA CRM 385, Ocean Sediment; USGS BCR-2, Columbia River Basalt; and USGS BHVO-2, Hawaiian Volcanic Observatory Basalt. These materials reflect a wide range in long-lived actinide concentrations (e.g. 1E4 to 1E10 atoms 239Pu/g) and isotope ratios. Measurements were performed in a clean laboratory by isotope dilution, multi-collector thermal ionization and multi-collector inductively coupled plasma mass spectrometry. In general, our results are in agreement with, but lower the uncertainty of, literature or certificate values for these reference materials. Our uranium results for the basalts also confirm previously reported high-precision mass spectrometric results from our laboratory. In many cases our measurements of U-Pu-Np-Am nuclides appear to be novel.Extensive results for NIST SRM 4350b, River Sediment, indicate that this material is heterogeneous for Pu-Np-Am concentrations and isotope ratios at a sample size of 5 g or lower. Pu–Np isotope ratios and a241Pu-241Am model age of 1954 reflect a mix of plutonium production operations at the nearby Hanford, Washington site, and global atmospheric fallout from nuclear weapons testing. Results for the oceanic sediment materials (NIST SRM 4357 and IAEA 385) collected near Sellafield, U.K. vary but are also indicative of local anthropogenic sources of varying Pu isotopic composition and a mean 241Pu-241Am model age of 1964. Large environmental fractionation between Pu and Np is observed for the ocean, river, and lake sediment reference materials. Novel measurements for the two air particulate SRMs indicate high U, Pu and Np concentrations for these collections in 1976–1977 with an anomalous regional fallout Pu isotopic signature. Results for BHVO-2 and other Hawaiian basalts indicate that those which erupted before or during the period of abundant atmospheric nuclear weapons testing (1950–1970) contain significant levels of Pu (on the order of 1E7 atoms 239Pu/g) with a global fallout Pu isotopic composition, compared to more recent eruptions which incorporated less Pu. Hence, Hawaiian basalts may provide an integrated temporal record of anthropogenic actinide fallout deposition from the atmosphere since eruption.

Fallout from Nuclear Weapons Tests: Environmental, Health, Political, and Sociological Considerations.

The process of nuclear fission, which was discovered in 1938, opened the door to the production of nuclear weapons, which were used in 1945 by the United States against Japan in World War II, and to the detonation of >500 nuclear weapons tests in the atmosphere by the United States, the former Soviet Union, the United Kingdom, China, and France from 1946-1980. Hundreds of radionuclides, most of them short-lived, were produced in the atmospheric tests. The radioactive clouds produced by the explosions were usually partitioned between the troposphere and the stratosphere: the activity that remained in the troposphere resulted in local and regional fallout, consisting mainly of short-lived radionuclides and in relatively high doses for the populations residing in the vicinity of the test site, whereas the activity that reached the stratosphere returned to the ground with a half-life of ~1 y and was composed of long-lived radionuclides that contaminated all uncovered materials on Earth to a small extent and led to low-level irradiation of the world population for decades or more. The health effects resulting from exposure to radioactive fallout constitute, in most cases, small excesses over baseline rates for thyroid cancer and leukemia. An extra 49,000 cases of thyroid cancer would be expected to occur among the US population from exposure to radioactive fallout from the atmospheric nuclear weapons tests that were conducted at the Nevada Test Site in the 1950s. In addition, there could be as many as 11,000 deaths from non-thyroid cancers related to fallout from all atmospheric tests that were conducted at all sites in the world, with leukemia making up 10% of the total. Public concern arose in part from the secrecy that surrounded the nuclear testing programs and, for a long time, the poor communication regarding the consequences of the tests, both in terms of radiation doses and of health effects. Sociological and political pressures contributed to the establishment of programs of compensation for radiation exposures and evidence of radiation-induced diseases in countries that incurred significant fallout from nuclear weapons testing.

Distribution of hydrometeors in monsoonal clouds over the South American continent during the austral summer monsoon: GPM observations

ABSTRACTThe Global precipitation measurement (GPM) was launched in February 2014 and provides the three-dimensional attenuated corrected radar reflectivity factor (Ze) along with the raindrop size distribution (DSD) parameters. The DSD parameters consist of the mass-weighted hydrometeors size (Dm in mm) and normalized hydrometeors concentration (Nw in mm−1 m−3). The present study investigates the vertical and spatial distribution of hydrometeors in intense convective clouds that form over South America (SA) during Austral summer monsoon seasons. We defined Cumulonimbus towers (CbTs) and intense convective cells based on 8 km (ICC8s) and 3 km (ICC3s), using vertical profile of radar reflectivity algorithm and then their properties are explored over eight selected areas over SA. CbT is defined by using the Ze≥20 dBZ at 12 km with base height less than 3 km altitude. The ICCs are defined by using the Ze thresholds at 8 and 3 km altitude, and Ze threshold value belongs to the top 5% of the Ze value at the reference height. Subtropical areas including Sierra de Cordoba (SDC) and La Plata basin (LPB) consist of a higher frequency of CbTs and ICC8s, whereas ICC3 is nearly uniformly distributed over the SA continent and the Atlantic Ocean (AO). Eastern foothills of the Andes mountain also consist of a higher frequency of CbTs and ICC8s. Irrespective of the height and Ze thresholds used in the present study, the SDC and LPB consist of the most intense convective clouds with higher echo top altitude, and similar to that observed over Western Himalaya foothills over South Asia. Land and ocean differences are visible in the cloud cells based on the 3 km reference height, which is well below the freezing level. CbTs and ICC8s do not show the land and ocean differences as in both the cases the AO has comparable Ze in average vertical profiles compared to the land areas, but in ICC3, the AO has the weakest cloud cells with the least cloud top height. The absolute slope of Ze in mixed-phase altitude is highest in ICC3 and reflect the local precipitation fallout in mixed-phase regions and suggested that fewer hydrometeors of larger sized are lifted in the upper atmosphere. The least slope over SDC and Central Foothills indicates that higher sized of hydrometeors are lifted in the upper atmosphere in the monsoonal clouds compared to other parts of SA continent. The DSD parameters indicate that in general, intense cloud cells consist of large-sized hydrometeors although their concentration is low. The spatial averages of the DSD parameters also indicate larger sized of hydrometeors exist on average for all types of clouds at 3 and 8 km in southeastern areas of SA including SDC, LPB, and Brazilian highlands. The single meteorological feature is not responsible for the intense and deep convection, but the combined meteorological variables are responsible for producing the intense and deeper convection.

Distribution of neptunium and plutonium in New Mexico lichen samples (Usnea arizonica) contaminated by atmospheric fallout

The concentrations of 237Np, 239Pu and 240Pu were determined in lichen samples (Usnea arizonica) that were collected from ten locations in New Mexico between 2011 and 2013 using isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS). The observed isotopic ratios for 237Np/239Pu and 240Pu/239Pu indicate trace contamination from global and regional fallout (e.g. Trinity test and atmospheric testing at the Nevada Test Site). The fact that actinide contamination is detected in recent lichen collections suggests continuous re-suspension of fallout radionuclides even 50 years after ratification of the Limited Test Ban Treaty.

Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout.

For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m2) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The 240Pu/239Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China.

Nigeria's 2015 Election in Perspective

As Nigeria moves closer to its 2015 elections, there are concerns that the elections, like the previous ones, will be marred by violence. This article examines why elections are usually volatile in Nigeria, the main sources of apprehensions regarding the 2015 elections, the key issues that might define the elections, factors that might mitigate the outbreak of violence, and the national and regional fallout that can be expected.

Processing of analogues of plume fallout in cold regions of Enceladus by energetic electrons

Enceladus, a small icy moon of Saturn, is one of the most remarkable bodies in the solar system. This moon is a geologically active object, and despite the lower temperatures on most of its surface, the geothermally heated south polar region presents geysers that spouts a plume made of water (approximately ninety percent), carbon dioxide, methane, ammonia, and methanol, among other molecules. Most of the upward-moving particles do not have the velocity to escape from the gravitational influence of the moon and fall back to the surface. The molecules in the ice are continuously exposed to ionizing radiation, such as UV and X-rays photons, cosmic rays, and electrons. Over time, the ionizing radiation promotes molecular bond rupture, destroying and also forming molecules, radicals, and fragments. We analyse the processing of an ice mixture analogue to the Enceladus fallout ice in cold resurfaced areas (north pole) by 1 keV electrons. The main goal is to search for complex species that have not yet been detected in this moon, and to determine relevant physico-chemical parameters, such as destruction and formation cross-sections and the half-life of the studied molecules in the ice. The experiment consisted of the electron irradiation of an Enceladus-like ice mixture (H2O,CO2,CH4,NH3, and CH3OH) in an ultra-high vacuum chamber at 20 K. The analysis was made by infrared spectrometry in the mid-infrared region (4000-800 cm-1 or 2.5-12.5 microns).The absolute dissociation cross-sections of the parent molecules, the formation cross-section of daughter species, and the half-life of the parental species in a simulated Enceladus irradiation scenario were determined. Among the produced species, CO (carbon monoxide), OCN- (cyanate anion), HCONH2 (formamide), and H2CO (formaldehyde) were tentatively detected.

Israel's Place in a Changing Regional Order (1948–2013)

In Israel’s earlier years it feared the great potential of Arab military power. Israel’s founding fathers constantly agonized over the balance of power with the Arabs, which they expected to change with time in the Arabs’ favor. They did not and could not have foreseen Arab weakness and decline. In recent years the Arabs, generally speaking, instead of going from strength to strength, have become a conglomerate of failed or failing states paving the way for the proliferation of a host of dangerous non-state actors. Therefore, as opposed to Israel’s earlier appraisals, the country’s current concerns are related not to the power of the Arabs but to the regional fall-out of Arab weakness.

Alimentary tract absorption (f1 values) for radionuclides in local and regional fallout from nuclear tests.

This paper presents gastrointestinal absorption fractions (f1 values) for estimating internal doses from local and regional fallout radionuclides due to nuclear tests. The choice of f1 values are based on specific circumstances of weapons test conditions and a review of reported f1 values for elements in different physical and chemical states. Special attention is given to fallout from nuclear tests conducted at the Marshall Islands. We make a distinction between the f1 values for intakes of radioactive materials immediately after deposition (acute intakes) and intakes that occur in the course of months and years after deposition, following incorporation into terrestrial and aquatic foodstuffs (chronic intakes). Multiple f1 values for different circumstances where persons are exposed to radioactive fallout (e.g., local vs. regional fallout and coral vs. continental tests) are presented when supportive information is available. In some cases, our selected f1 values are similar to those adopted by the International Commission on Radiological Protection (ICRP) (e.g., iodine and most actinides). However, f1 values for cesium and strontium derived from urine bioassay data of the Marshallese population are notably lower than the generic f1 values recommended by ICRP, particularly for acute intakes from local fallout (0.4 and 0.05 for Cs and Sr, respectively). The f1 values presented here form the first complete set of values relevant to realistic dose assessments for exposure to local or regional radioactive fallout.

Arctic Ocean sea ice drift origin derived from artificial radionuclides

Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these radionuclides in SIS. The distribution of 137Cs and 239,240Pu activities and the 240Pu/ 239Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The 240Pu/ 239Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara–Laptev Sea and the Alaskan shelf. However, if the 240Pu/ 239Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the 137Cs and 239,240Pu activities. Therefore, these anthropogenic radionuclides can be used in many instances to determine the geographical source area of sea-ice.

Vertical Distributions of Plutonium and 137Cs in Lacustrine Sediments in Northwestern China: Quantifying Sediment Accumulation Rates and Source Identifications

We investigated the vertical distributions of 239+240Pu and 137Cs activities and 240Pu/239Pu atom ratios in two lakes in northwestern China. The 240Pu/239Pu atom ratio from the Chinese nuclear test (CNT) site at Lop Nor is too complicated to identify the regional fallout source. However, radionuclides from the test site may be resolved mainly by the vertical distribution of radionuclides because there is no overlap between the global fallout peak and the local fallout peak. We analyzed Pu isotopes and 137Cs in sediments from two lakes (Sugan and Shuangta) located in northwestern China, near the CNT, and Lake Sihailongwan located in northeastern China to date recent lacustrine sediments and resolve global/local fallout sources. The apparently low 240Pu/239Pu atom ratio of 0.103 +/- 0.010 at Lake Sugan was likely representative of the fallout from the Lop Nor site. Our results also demonstrated that the 239+240Pu activity was more useful for recent chronology of lacustrine sediments, compared to 137Cs. Sediment accumulation rates of 0.651, 0.058-0.061, and 0.015 g x cm(-2) x a(-1) for sediment cores of Lake Shuangta, Lake Sugan and Lake Sihailongwan, respectively, were obtained by using the 239+240Pu fallout peak as a discrete time marker for 1964. The respective contributions of 137Cs and 239+240Pu from the CNT were estimated to be about 40 and 27% for Lake Sugan and 36 and 20% for Lake Shuangta. Plutonium isotopes in lacustrine sediments were proven to be useful for quantifying sediment accumulation rates and for source identification of the radioactive contamination.

The Muslim Brotherhood and the Emerging ‘Shia Crescent’

To form a more prudent foreign policy toward the Muslim Brotherhood, we must understand it not only as a domestic actor, but also as a major regional player. In fact, the Brotherhood has a complex relationship with Iran and the Shias, which blurs the lines of the so-called Shia Crescent. This article addresses the Muslim Brotherhood's foreign/regional policy by analyzing its attitude toward the Shias and Iran, thus placing it within the context of the emerging regional order. Addressing the complex relationship between the Muslim Brotherhood and the Shias/Iran will help to clarify the regional fallout were the Brotherhood to gain control of a major Sunni Arab state. This is a vital issue for policy makers who are considering the U.S. position vis-à-vis the Brotherhood.

Saudi Arabia: the ‘arab street’, the media and popular agitation since September 11

Dr Mai Yamani studied Anthropology at Bryn Mawr and Oxford. She has taught at King Abdul Aziz University in Saudi Arabia, and lectured widely in the Middle East, Europe and the United States. She is currently an Associate Research Fellow at the Royal Institute of International Affairs, where she has participated in conferences in the Middle East Programme. In February 2003 she, with others in the RIIA Programme, published Iraq, the Regional Fallout, which is available on the RIIA website. She has written numerous articles and her book, Changed Identities: the Challenge of the New Generation in Saudi Arabia (Royal Institute for International Affairs, 2001) was reviewed in the February 2002 issue of Asian Affairs.

SAUDI ARABIA: THE 'ARAB STREET', THE MEDIA AND POPULAR AGITATION SINCE SEPTEMBER 11

Dr Mai Yamani studied Anthropology at Bryn Mawr and Oxford. She has taught at King Abdul Aziz University in Saudi Arabia, and lectured widely in the Middle East, Europe and the United States. She is currently an Associate Research Fellow at the Royal Institute of International Affairs, where she has participated in conferences in the Middle East Programme. In February 2003 she, with others in the RIIA Programme, published Iraq, the Regional Fallout, which is available on the RIIA website. She has written numerous articles and her book, Changed Identities: the Challenge of the New Generation in Saudi Arabia (Royal Institute for International Affairs, 2001) was reviewed in the February 2002 issue of Asian Affairs.

Capelinhos 1957–1958, Faial, Azores: deposits formed by an emergent surtseyan eruption

The 1957–1958 eruption of Capelinhos, Faial island, Azores, involved three periods of surtseyan, hydromagmatic activity: two in 1957 and one in 1958. Deposits from this eruption are exposed both in sea cliffs cut into the flanks of the tuff cone and more distally >1 km from the vent. Five lithofacies are identified: lithofacies I is composed of even thickness beds with laterally continuous internal stratigraphy and is interpreted to have been formed by fallout. Lithofacies II consists of beds with internally discontinuous lenses, and has sand-wave structures that increase in abundance toward the outer margins of the tuff cone. This lithofacies is interpreted as having been deposited from pyroclastic surges. Lithofacies III is composed of mantle-bedded deposits with laterally discontinuous internal stratigraphy. This lithofacies is interpreted to have been formed by hybrid processes where fallout of tephra occurred simultaneously with pyroclastic surges. In the outer flanks of the tuff cone, lithofacies III grades laterally into fallout beds of lithofacies I. Lithofacies IV consists of alternating beds of coarse ash aggregates and non-aggregated fine ash, and is particularly well developed in distal regions. Some of this facies was formed by fallout. Alternating beds also occur plastered against obstacles up to 2 km from the vent, indicating an origin from wet pyroclastic surges. The orientation of plastered tephra indicates that the surges were deflected by topography as they decelerated. The distinction between surge and fallout in distal regions is uncertain because wind-drifted fallout and decelerating surge clouds can generate similar deposits. Lithofacies V consists of scoria lapilli beds interpreted to be fallout from hawaiian-style fire-fountaining in the later stages of the eruption. Juvenile pyroclasts within hydromagmatic deposits are predominantly poorly vesicular (25–60% of clasts <30% vesicles). However, on both micro- and macroscopic scales, there is a wide range in clast vesicularity (up to 70% vesicles) indicating that, although fragmentation was predominantly hydromagmatic, vesiculation and magmatic-volatile-driven fragmentation operated simultaneously.

The collapse of the Soviet empire: managing the regional fall-out

Journal Article The collapse of the Soviet empire: managing the regional fall-out Get access The collapse of the Soviet empire: managing the regional fall-out. Edited by Trevor Taylor. London: Royal Institute of International Affairs and International Institute for Global Peace, Tokyo 1992. 189pp. Pb.: £10.50. ISBN 0 905031 54 7. Stuart Croft Stuart Croft 1University of Birmingham Search for other works by this author on: Oxford Academic Google Scholar International Affairs, Volume 69, Issue 2, April 1993, Pages 388–389, https://doi.org/10.2307/2621680 Published: 01 April 1993

The Collapse of the Soviet Empire: Managing the Regional Fall-Out.

The Collapse of the Soviet Empire: Managing the Regional Fall-Out.

The Collapse of the Soviet Empire: Managing the Regional Fallout

In the dynamic political climate after the end of the Cold War and the collapse of the Soviet Union, the world has experienced a series of dramatic developments. While many of these have taken place in and around Europe, they are still of prime importance to Japan, with its global economic and political interests as well as its immediate regional security concerns. In this fast-moving atmosphere, the International Institute for Global Peace in Tokyo and the Royal Institute of International Affairs in London organized a two-year research project to address security issues on a global scale and to look at the common concerns of Western Europe and Japan. This book - the first in a projected series on security challenges for Japan and Europe in a post-Cold War world - focuses on the former Soviet Union and the multi-dimensional consequences of its collapse for the security of its eastern and western neighbours.