Atmospheric Weapons Tests Research Articles

Bomb 137Cs in modern honey reveals a regional soil control on pollutant cycling by plants

137Cs is a long-lived (30-year radioactive half-life) fission product dispersed globally by mid-20th century atmospheric nuclear weapons testing. Here we show that vegetation thousands of kilometers from testing sites continues to cycle 137Cs because it mimics potassium, and consequently, bees magnify this radionuclide in honey. There were no atmospheric weapons tests in the eastern United States, but most honey here has detectable 137Cs at >0.03 Bq kg−1, and in the southeastern U.S., activities can be >500 times higher. By measuring honey, we show regional patterns in the biogeochemical cycling of 137Cs and conclude that plants and animals receive disproportionally high exposure to ionizing radiation from 137Cs in low potassium soils. In several cases, the presence of 137Cs more than doubled the ionizing radiation from gamma and x-rays in the honey, indicating that despite its radioactive half-life, the environmental legacy of regional 137Cs pollution can persist for more than six decades.

Forensic Radiocarbon Dating of Human Remains

Radiocarbon dating is a valuable tool for the forensic examination of human remains in answering questions as to whether the remains are of forensic or medico-legal interest or archaeological in date. The technique is also potentially capable of providing the year of birth and/or death of an individual. Atmospheric radiocarbon levels are currently enhanced relative to the natural level due to the release of large quantities of radiocarbon (14C) during the atmospheric nuclear weapons testing of the 1950s and 1960s. This spike, or “bomb-pulse,” can, in some instances, provide precision dates to within 1–2 calendar years. However, atmospheric 14C activity has been declining since the end of atmospheric weapons testing in 1963 and is likely to drop below the natural level by the mid-twenty-first century, with implications for the application of radiocarbon dating to forensic specimens.

Measurements of cesium in Arctic beluga and caribou before and after the Fukushima accident of 2011

Concern from northern communities following the Fukushima Daiichi nuclear accident of March 2011 has prompted a reassessment of the safety of their traditional foods with respect to radioactivity levels. To this end, a study was conducted to measure the levels of radionuclides in Arctic caribou (Rangifer tarandus) and beluga (Delphinapterus leucas). The main radionuclide of concern is cesium-137, which is easily transferred through the lichen-caribou food chain. Previous studies have been conducted on the cesium-137 levels in Canadian caribou herds from 1958 to 2000, allowing researchers to determine the amount of cesium-137 in caribou specifically attributable to atmospheric weapons testing and the Chernobyl nuclear accident in 1986. In this study, samples of lichens, mushrooms, caribou, beluga and beluga prey collected before and after the Fukushima accident were analyzed for radioactivity levels. Samples were processed and measured using gamma ray spectroscopy to identify the radionuclides present and determine the radioactivity concentration. Both calibration standards and Monte Carlo simulations were used to determine the efficiency of the detectors for the samples, taking into account differences in individual sample sizes as well as matrices. In particular, a careful analysis of the atomic composition of lichens and mushrooms was performed to ensure the efficiencies for these sample types were correct. A comparison of the concentrations from before and after the accident indicated that there was no increase in radioactivity as a result of the atmospheric plume from the Fukushima accident. Some cesium-137, likely attributable to fallout from atmospheric weapons testing of the 1950s and 1960s (since there was no cesium-134 measured in the samples), was measured in the post Fukushima caribou and beluga whale samples; however, this amount was determined to be insignificant for any radiological concern (9.1 ± 1.8 and 0.63 ± 0.23 Bq kg−1 ww respectively). The activity concentrations of cesium-137 was about 200 times smaller than that of natural radioactive potassium in the beluga samples. Both the caribou and beluga results showed that these foods continue to be a healthy food choice for northern Canadians with respect to radioactivity, and this result has been communicated to the nearby northern communities and stakeholders.

“Radiation is Not New to Our Lives”: The U.S. Atomic Energy Commission, Continental Atmospheric Weapons Testing, and Discursive Hegemony in the Downwind Communities

AbstractDrawing from the post‐structuralist discourse theory of Laclau and Mouffe and corpus linguistics techniques, we deconstruct the discursive strategies of the U.S. Atomic Energy Commission (AEC) during the era of continental atmospheric atomic testing in southern Nevada. The data consist of AEC pamphlets distributed in the “downwind” communities in 1953, 1955, and 1957 coincident with major test series. We illustrate discursive dominance hinged on the invocation of national security and instrumental rationality as key signifiers and portrayal of radioactive fallout as natural, ubiquitous, and controllable. Further, AEC discourse was predicated upon casting officials in a paternalistic role and residents of the rural communities downwind as best served though acquiescence to AEC authority and expertise. We conclude by highlighting the empirical evidence regarding the deleterious health effects of atmospheric atomic testing between 1951 and 1962 and argue examination of AEC discursive hegemony offers important lessons applicable to contemporary socio‐technical controversies.

Tritium in Australian precipitation: A 50 year record

Summary Tritium in precipitation has been measured in Australia over the past 50 years, as an essential research tool in hydro-climate studies, and to contribute to the Global Network for Isotopes in Precipitation (GNIP). Tritium, a component of the water molecule (HTO), is the only true age tracer for waters. The elevated level of tritium in the environment as a result of last century’s atmospheric thermonuclear testing delivers the benefit of tracing groundwater systems over a 100 year timeframe. The concentration of tritium in Australian precipitation reached a maximum of 160 Tritium Units (TU) in 1963, during one of the most intense periods of nuclear weapons testing. From 1963 to present we observe a rapid drop in the concentration of tritium, more than expected from natural decay, and this can be attributed to the wash out of tritium into the oceans and groundwater. Spikes in the tritium level are superimposed over this general trend; the first around 1969, with levels ranging from 39.4 to 84.4 TU was due to French atmospheric weapon testing, and again in 1990, levels peaked between 6.6 and 12.9 TU, which is attributed to tritium leaking from underground tests in the French Pacific. Since 1990 the levels of tritium have declined globally and regionally. Currently the levels of tritium in Australia are stabilising to around 2–3 TU increasing with latitude across the continent, suggesting that today the tritium in precipitation is predominantly natural. The spatial distribution of tritium is presented and found to be dominated by the annual stratosphere–troposphere exchange in combination with latitude and continental effects. A precipitation amount effect is also observed for inland sites.

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

The isotopes 239 Pu and 240 Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes constitute artificial tracers of recent soil erosion and sediment movement. In practice the high throughput capabilities and high sensitivity of the AMS technique makes the study of Australia's geographically large areas viable using Pu isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The contribution from the Maralinga tests to the Pu isotopic abundances present in the region around Maralinga is largely unknown. In global fallout, for example, the 240 Pu/ 239 Pu ratio is typically in the range 0.17 - 0.19, but the influence of the regional tests could lead to values outside this range. This would impact on the assessment techniques used in the soil and sediment tracer studies. We report recent measurements on soil samples collected from across the Maralinga Test site.

Historical reconstruction of Plutonium contamination in the Swiss-Italian Alps

Plutonium is present in the environment as a consequence of atmospheric nuclear tests carried out in the 1960s, nuclear weapons production and releases by the nuclear industry over the past 50 years. Approximately 6 tons of 239 Pu have been released into the environment as a result of 541 atmospheric weapon tests Nuclear Pu fallout has been studied in various environmental archives, such as sediments, soil and herbarium grass. Mid-latitude ice cores have been studied as well, on Mont Blanc, the Western Alps and on Belukha Glacier, Siberian Altai. We present a Pu record obtained by analyzing 52 discrete samples of an alpine firn/ice core from Colle Gnifetti (M. Rosa, 4450 m a.s.l.), dating from 1945 to 1991. The 239 Pu signal was recorded directly, without preliminary cleaning or preconcentration steps, using an high resolution inductively plasma mass spectrometer equipped with a desolvation system. The 239 Pu profile reflects the three main periods of atmospheric nuclear weapons testing: the earliest peak lasted from 1954/55 to 1958 and was caused by the first testing period reaching a maximum in 1958. Despite a temporary halt of testing in 1959/60, the Pu concentration decreased only by half with respect to the 1958 peak due to long atmospheric residence times. In 1961/62 Pu concentrations rapidly increased reaching a maximum in 1963. After the signing of the Limited Test Ban Treaty between USA and USSR in 1964, Pu deposition decreased very sharply reaching a minimum in 1967. The third period (1967-1975) is characterized by irregular Pu concentrations with smaller peaks which might be related to the deposition of Saharan dust contaminated by the French nuclear tests of the 1960s.

Inventories and concentration profiles of 137Cs in undisturbed soils in the northeast of Buenos Aires Province, Argentina

Inventories and vertical distribution of 137Cs were determined in La Plata region undisturbed soils, Argentina. A mean inventory value of 891 ± 220 Bq/m2 was established, which is compatible with the values expected from atmospheric weapon tests fallout. The study was complemented with pH, organic carbon fraction, texture and mineralogical soil analyses. Putting together Southern Hemisphere 137Cs inventory data, it is possible to correlate these data with the mean annual precipitations. The large differences in 137Cs concentration profiles were attributed to soil properties, especially the clay content and the pH values.A convection–dispersion model with irreversible retention was used to fit the activity concentration profiles. The obtained effective diffusion coefficient and effective convection velocity parameters values were in the range from 0.2 cm2/y to 0.4 cm2/y and from 0.23 cm/y to 0.43 cm/y, respectively. These data are in agreement with values reported in literature. In general, with the growth of clay content in the soil, there was an increase in the transfer rate from free to bound state. Finally, the highest transfer rate from free to bound state was obtained for soil pH value equal to 8.

Observations of Fukushima fallout in Great Britain

Following the Fukushima accident in March 2011, grass samples were collected from 42 sites around Great Britain during April 2011. Iodine-131 was measurable in grass samples across the country with activity concentrations ranging from 10 to 55 Bq kg−1 dry matter. Concentrations were similar to those reported in other European countries. Rainwater and some foodstuffs were also analysed from a limited number of sites. Of these, 131I was only detectable in sheep’s milk (c. 2 Bq kg−1). Caesium-134, which can be attributed to releases from the Fukushima reactors, was detectable in six of the grass samples (4–8 Bq kg−1 dry matter); 137Cs was detected in a larger number of grass samples although previous release sources (atmospheric weapons test and the 1986 Chernobyl and 1957 Windscale accidents) are likely to have contributed to this.

Temporal trends in childhood leukaemia incidence following exposure to radioactive fallout from atmospheric nuclear weapons testing

Notably raised rates of childhood leukaemia incidence have been found near some nuclear installations, in particular Sellafield and Dounreay in the United Kingdom, but risk assessments have concluded that the radiation doses estimated to have been received by children or in utero as a result of operations at these installations are much too small to account for the reported increases in incidence. This has led to speculation that the risk of childhood leukaemia arising from internal exposure to radiation following the intake of radioactive material released from nuclear facilities has been substantially underestimated. The radionuclides discharged from many nuclear installations are similar to those released into the global environment by atmospheric nuclear weapons testing, which was at its height in the late-1950s and early-1960s. Measurements of anthropogenic radionuclides in members of the general public resident in the vicinity of Sellafield and Dounreay have found levels that do not differ greatly from those in persons living remote from nuclear installations that are due to ubiquitous exposure to the radioactive debris of nuclear weapons testing. Therefore, if the leukaemia risk to children resulting from deposition within the body of radioactive material discharged from nuclear facilities has been grossly underestimated, then a pronounced excess of childhood leukaemia would have been expected as a consequence of the short period of intense atmospheric weapons testing. We have examined childhood leukaemia incidence in 11 large-scale cancer registries in three continents for which data were available at least as early as 1962. We found no evidence of a wave of excess cases corresponding to the peak of radioactive fallout from atmospheric weapons testing. The absence of a discernible increase in the incidence of childhood leukaemia following the period of maximum exposure to the radioactive debris of this testing weighs heavily against the suggestion that conventional methods are seriously in error when assessing the risk of childhood leukaemia from exposure to man-made radionuclides released from nuclear installations.

Introduction to a Virtual Special Issue: probing the carbon cycle with 13C

Introduction to a <i>Virtual Special Issue</i>: probing the carbon cycle with ¹³C

Potential of lichens for monitoring iodine-129 and chlorine-36

Chlorine-36 (half life 3.01 × 105 year), a beta emitter, is produced naturally but its presence has been enhanced by atmospheric weapons testing and other nuclear activities. Iodine-129 has a half life of 1.57 × 107 years and is also produced by nuclear activities, in particular fuel reprocessing. Many elements have a long biological half-life in lichens, which were thus investigated so as to assess their suitability for 36Cl and 129I monitoring. Lichens sampled between 1998 and 2008 were analysed for total chlorine, and selected samples were processed for 36Cl measurement using Accelerator Mass Spectrometry (AMS); 129I was analyzed by gamma spectrometry. Different aspects are discussed: long-term storage in lichens versus environmental mobility, levels in samples collected near a reprocessing facility, and potential for spatial and temporal monitoring.

Measurement of uranium and its isotopes at trace levels in environmental samples using mass spectrometry

Actinides have widely entered the environment as a result of nuclear accidents and atmospheric weapon testing. These radionuclides, especially uranium, are outstanding radioactive pollutants, due to their high radiotoxicity and long half-lives. In addition to this, since depleted uranium (DU) has been used in the Balkan conflict in 1999, there has been a concern about the possible consequences of its use for the people and environment. Therefore, accurate, precise and simple determination methods are necessary in order to evaluate the human dose and the concentration and effects of these nuclides in the environment. The principal isotopes of uranium e.g.235U and 238U are of primordial origin and 234U present in radioactive equilibrium with 238U. 236U occurs in nature at ultra trace concentrations with a 236U: 238U atom ratio of 10−14. Concentrations of uranium in soil samples were determined using inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratios of uranium were measured using a thermal ionisation mass spectrometer. Radioactive dis-equilibrium of 234/238U, depletion of 235/238U and significant evidence of 236U/238U were noticed in soil samples.

Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us?

Abstract. Little is known about how the methane source inventory and sinks have evolved over recent centuries. New and detailed records of methane mixing ratio and isotopic composition (12CH4, 13CH4 and 14CH4) from analyses of air trapped in polar ice and firn can enhance this knowledge. We use existing bottom-up constructions of the source history, including "EDGAR"-based constructions, as inputs to a model of the evolving global budget for methane and for its carbon isotope composition through the 20th century. By matching such budgets to atmospheric data, we examine the constraints imposed by isotope information on those budget evolutions. Reconciling both 12CH4 and 13CH4 budgets with EDGAR-based source histories requires a combination of: a greater proportion of emissions from biomass burning and/or of fossil methane than EDGAR constructions suggest; a greater contribution from natural such emissions than is commonly supposed; and/or a significant role for active chlorine or other highly-fractionating tropospheric sink as has been independently proposed. Examining a companion budget evolution for 14CH4 exposes uncertainties in inferring the fossil-methane source from atmospheric 14CH4 data. Specifically, methane evolution during the nuclear era is sensitive to the cycling dynamics of "bomb 14C" (originating from atmospheric weapons tests) through the biosphere. In addition, since ca. 1970, direct production and release of 14CH4 from nuclear-power facilities is influential but poorly quantified. Atmospheric 14CH4 determinations in the nuclear era have the potential to better characterize both biospheric carbon cycling, from photosynthesis to methane synthesis, and the nuclear-power source.

137Cs in French soils: Deposition patterns and 15-year evolution

Around 2000 surface samples have been taken from French soil at around twenty stations over the last fifteen years. Caesium 137, the only artificial radionuclide in the terrestrial environment currently detectable with gamma spectroscopy, was measured in the samples. The levels of caesium activity were compared to deposition estimates for deposits from atmospheric weapons tests and Chernobyl fallout. Since the start of data acquisition, specific activity in the samples has decreased with a mean effective half-life of between 8 and 11 y, for meadow soil and agricultural soil respectively. These field observations confirm that the conventional soil migration-retention model, which uses distribution coefficient Kd, is insufficient for modelling caesium distribution in the surface soil layer. Although the differences between sites tend to diminish with time, surface specific activity in agricultural and meadow soil varies on average from a few Bq to several tens of Bq per kg of dry matter.

Migration processes of 137Cs and 90Sr in compartments of a lake ecosystem

The dispersion of radioactive substances in the environment following nuclear weapon tests in atmosphere since 1954 and accidents to nuclear plants, like that in Chernobyl in 1986, have allowed us to study the migration processes of some radionuclides in complex ecosystems such as lakes are. In the present paper the behavior of 137Cs and 90Sr in different compartments of the Monterosi Lake (central Italy) was assessed. The 137Cs concentration was measured in lake water as well as sediment, stream water, aquatic plant and fish samples. 90Sr concentration in water and sediments was also determined. A total inventory of 4206±76 Bq . m-2 and 958±79 Bq . m-2 (on 27/6/01) has been found for 137Cs and 90Sr, respectively. The experimental data presented here allow to calibrate theoretical models predicting the temporal trend of radionuclide concentration in similar ecosystems. Moreover, information on cesium and strontium migration processes can be extended to other pollutants having similar environmental behavior.

Plutonium isotope ratios in the Yenisey and Ob estuaries

Over the past 50 years, nuclear weapons’ tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems. The data indicated a clear influence from a low 240Pu: 239Pu source in surface sediments collected from the Yenisey estuary, whereas plutonium in Ob estuary sediments is dominated by global fallout. The results also show an increase in plutonium concentration (from 0.003 to 11 Bq/kg) and a decrease in 240Pu: 239Pu isotope ratio (from 0.16 to 0.05) going upstream from the Yenisey estuary towards the nuclear installation at Krashnoyarsk.

Plutonium in the arctic marine environment--a short review.

Anthropogenic plutonium has been introduced into the environment over the past 50 years as the result of the detonation of nuclear weapons and operational releases from the nuclear industry. In the Arctic environment, the main source of plutonium is from atmospheric weapons testing, which has resulted in a relatively uniform, underlying global distribution of plutonium. Previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases have given rise to enhanced local concentrations. Since different plutonium sources are characterised by distinctive plutonium-isotope ratios, evidence of a localised influence can be supported by clear perturbations in the plutonium-isotope ratio fingerprints as compared to the known ratio in global fallout. In Kara Sea sites, such perturbations have been observed as a result of underwater weapons tests at Chernaya Bay, dumped radioactive waste in Novaya Zemlya, and terrestrial runoff from the Ob and Yenisey Rivers. Measurement of the plutonium-isotope ratios offers both a means of identifying the origin of radionuclide contamination and the influence of the various nuclear installations on inputs to the Arctic, as well as a potential method for following the movement of water and sediment loads in the rivers.

An unexpected rise in strontium-90 in US deciduous teeth in the 1990s

For several decades, the United States has been without an ongoing program measuring levels of fission products in the body. Strontium-90 (Sr-90) concentrations in 2089 deciduous (baby) teeth, mostly from persons living near nuclear power reactors, reveal that average levels rose 48.5% for persons born in the late 1990s compared to those born in the late 1980s. This trend represents the first sustained increase since the early 1960s, before atmospheric weapons tests were banned. The trend was consistent for each of the five states for which at least 130 teeth are available. The highest averages were found in southeastern Pennsylvania, and the lowest in California (San Francisco and Sacramento), neither of which is near an operating nuclear reactor. In each state studied, the average Sr-90 concentration is highest in counties situated closest to nuclear reactors. It is likely that, 40 years after large-scale atmospheric atomic bomb tests ended, much of the current in-body radioactivity represents nuclear reactor emissions.

Anthony Leonid Turkevich

Anthony Leonid Turkevich