Plutonium in the atmosphere: A global perspective

Accumulation of Environmental Radioactivity on the Surface of a High Arctic Ice Cap (Flade Isblink, NE Greenland)

Under climatic warming, glaciers are becoming a secondary source of atmospheric contaminants originally released into the environment decades ago. This phenomenon has been well-documented for glaciers near emission sources. However, less is known about polar ice sheets and ice caps. Radionuclides are one of the contaminants that can be remobilised through ice melting and accumulate in cryoconite material on the surface of glaciers. To understand the cycling of radionuclides in polar glacial contexts, we evaluate the radioactivity of cryoconite samples from Flade Isblink, a High Arctic ice cap in northeast Greenland. The measured radioactivity is among the highest reported across the High Arctic and the highest from Greenland. The high variability observed among the samples is explained by considering the different macroscopic features of single cryoconite deposits. The radioactivity source is compatible with the stratospheric reservoir established during atmospheric nuclear tests and with weapons-grade fissile fuel, likely originating from Novaya Zemlya proving grounds. This study shows that the ability of cryoconite to accumulate radioactivity in remote areas is undisputed, highlighting the need for a deeper understanding of the remobilisation of radioactive species in polar glacial contexts.

Review of the sources and behaviors of plutonium isotopes in the atmosphere and ocean

Plutonium, as well as fission products such as 137Cs, had been released into the earth environment in 1945 after the first atmospheric nuclear explosion of plutonium bomb in the desert of New Mexico (USA, July 16) and later over Nagasaki (August 9), followed then by many other explosions. Thus, plutonium cycling in the atmosphere and ocean has become a major public concern as a result of the radiological and chemical toxicity of plutonium. However, plutonium isotopes and 137Cs are important transient tracers of biogeochemical and physical processes in the environment, respectively. In this review, we show that both physical and chemical approaches are needed to comprehensively understand the behaviors of plutonium in the atmosphere and ocean. In the atmosphere, plutonium and 137Cs attach with aerosols; thus, plutonium moves according to physical and chemical processes in connection with aerosols; however, since plutonium is a chemically reactive element, its behavior in an aqueous environment is more complicated, because biogeochemical regulatory factors, in addition to geophysical regulatory factors, must be considered. Meanwhile, 137Cs is chemically inert in aqueous environments. Therefore, the biogeochemical characteristics of plutonium can be elucidated through a comparison with those of 137Cs, which show conservative properties and moves according to physical processes. Finally, we suggest that monitoring of both plutonium and 137Cs can help elucidate geophysical and biogeochemical changes from climate changes.

Optimisation of plutonium separations using TEVA cartridges and ICP-MS/MS analysis for applicability to large-scale studies in tropical soils

The analysis of plutonium (Pu) in soil samples can inform the understanding of soil erosion processes globally. However, there are specific challenges associated for analysis in tropical soils and so an optimal analytical methodology ensuring best sensitivity is critical. This method aimed to demonstrate the feasibility of sample preparation and analysis of Pu isotopes in African soils, considering the environmental and cost implications applicable to low-resource laboratories. The separation procedure builds upon previous work using TEVA columns, further demonstrating their usefulness for the reduction of uranium (U) interference in ICP-MS analysis with enhanced selectivity for Pu. Here several steps were optimised to enhance Pu recovery, reducing method blank concentration, and improving the separation efficiency through the determination of the elution profiles of U and Pu. The elimination of the complexing agent in the eluent, increased the spike recovery by improving matrix tolerance of the plasma, and simplified the separation procedure, improving throughput by 20%. The subsequent method was validated through the analysis of Certified Reference Material IAEA-384, where high accuracy and improved precision of measurement were demonstrated (measured value 114 ± 12 versus certified value 108 ± 13 Bq kg-1). Optimisation of the column separation, along with the analysis of the samples using O2 gas in ICP-MS/MS mode to mass shift Pu isotopes away from interfering molecular U ions provided a simple, robust, and cost-effective method with low achievable method detection limits of 0.18 pg kg-1 239+240Pu, applicable to the detection of ultra-trace fallout Pu in African soils.

Plutonium isotopes in the ground air layer in southern Poland (2010-2016): Source terms, seasonal variability and correlations with meteorological conditions

In this study, the results of the analysis of Pu-238 and Pu-239 + 240 activity concentrations on aerosol filters collected from 2010 to 2016 in Krakow (Southern Poland) are presented and discussed. For the first time, the temporal variation of Pu-239 + 240 activity concentration in surface air in Poland was studied using Fourier analysis. The analysis clearly showed that the Pu-239 + 240 content in the near-ground air layer is subject to seasonal variations and demonstrates annual periodicity. Pu analyses were performed using alpha spectrometry. The measured values ranged from 1.93∙10^-10 Bq/m³ to 1.31∙10^-8 Bq/m³ with an average of 2.07∙10^-9 Bq/m³ for Pu-239 + 240 and from 9.07∙10^-11 Bq/m³ to 1.27∙10^-9 Bq/m³ with the average 1.52∙10^-10 Bq/m³ for Pu-238. The analysis of the potential sources of plutonium isotopes in the air aerosols samples indicated that only two samples are uniquely characterized by the ratio corresponding to spent nuclear fuel: February 2012 (0.59 ± 0.18) and February 2015 (0.68 ± 0.19). The remaining samples showed mixed origins, with global radioactive fallout appearing to contribute more than spent nuclear fuel. To study the relationship between Pu-239 + 240 and meteorological conditions, Pearson's correlation and circulation pattern analyses were performed. The analyses showed that the Pu-239 + 240 activity concentration depends on air temperature (R = 0.51), the sum of ice and snowfall (R = -0.45), relative humidity (R = -0.54) and mean total cloud cover (R = -0.56). High concentrations of Pu-239 + 240 were positively correlated with air advection from the southern and eastern sectors, whereas low concentrations were observed during dynamic weather conditions with intense circulation from the western sector. In case of Pu-238 no significant correlation was observed.

A novel strategy for Pu determination in water samples by automated separation in combination with direct ICP-MS/MS measurement

Methods for Pu determination in water samples has been longtime studied but they generally involved tedious manual operations. In this context, we proposed a novel strategy for accurate determination of ultra-trace Pu in water samples by the combination of fully automated separation with direct ICP-MS/MS measurement. A recently commercialized extraction resin TK200 was used for single-column separation due to its distinctive nature. Acidified waters up to 1 L were directly loaded to the resin at high flow rate (15 mL min^-1) with omitting the frequently used co-precipitation process. Small volumes of dilute HNO₃ were used for column washing, and Pu was efficiently eluted within only 2 mL 0.5 mol L^-1 HCl-0.1 mol L^-1 HF with a stable recovery (65%). This separation procedure was fully automated under the control of user program, meanwhile the final eluent was compatible for direct ICP-MS/MS measurement without extra sample treatment. In that way, both the labor intensity and reagent consumption were minimized compared with existing methods. With the high decontamination (10⁴ to 10⁵) of U in the chemical separation and the further elimination of uranium hydrides under oxygen reaction model during ICP-MS/MS measurement, the overall interference yields of UH⁺/U⁺ and UH₂⁺/U⁺ were down to 10^-15. The limits of detection (LODs) of this method reached 0.32 μBq L^-1 for ²³⁹Pu and 2.00 μBq L^-1 for ²⁴⁰Pu, which were much lower than those stipulated in the general guidelines for drinking water standards, suggesting this method was promising in routine or emergency radiation monitoring. Furthermore, the established method was successfully applied in a pilot study to determine global fallout derived Pu in surface glacier samples with extremely low concentrations of ^239+240Pu, which suggested the method would also be feasible in glacial chronology studies in the future.

Research into the current radiological state of air and monitoring observations on STS and the adjacent territory

The article presents the assessment of levels and the pattern of STS air radioactive contamination. Levels of air radioactive contamination with artificial radionuclides at different distances from ground zeros of nuclear tests (0.08-10 km) were determined. The maximum concentration of ^239+240Pu in the air did not exceed 6.5·10^-3 Bq/m³ at the crater ridge of the "Atomic Lake", the one at the P3 technical site, the "Experimental Field", reached 1.6·10^-2 Bq/m³. Based upon monitoring observation data (2016-2021) on the STS territory, ^239+240Pu concentration in the air of the "Balapan" and "Degelen" sites varied between 3.0·10^-9 and 1.1·10^-6 Bq/m³. In settlements adjacent to the STS territory, ^239+240Pu concentrations in the air is: Kurchatov t. - 3.0·10^-9 to 6.0·10^-7 Bq/m³, the Dolon small village - 4.5·10^-9 to 5.8·10^-6 Bq/m³, the Sarzhal small village - 4.4·10^-7 to 1.3·10^-6 Bq/m³. Values derived for concentrations of artificial radionuclides at STS observation posts and the adjacent territory are at the level of background values for this region.

Distribution and migration of 239,240Pu in soil profiles in North China

The source, vertical distribution and migration behavior of plutonium in five soil profiles (from forest, grassland and desert areas) in northern China were investigated. The average ²⁴⁰Pu/²³⁹Pu atomic ratio of 0.184 ± 0.022 observed in these samples is in good agreement with the reported value of global fallout, suggesting that the global fallout is the major source of plutonium in northern China. The ^239,240Pu inventories in five soil profiles ranges from 43.3 Bq/m² to 175 Bq/m², lying in the reported range for global fallout in the similar latitude band. The effective convection velocity (0.04-0.16 cm/y) and effective dispersion coefficient (0.13-0.41cm²/y) of plutonium in different soil profiles derived using the CDE model varies significantly, attributed to multi-factors including location, topography, climate and soil types. The results showed that the migration of plutonium in grassland soil is significantly slow compared to other type of soil, especially desert soil.

An overview of plutonium isotopes in soils, China: Distribution, spatial patterns, and sources

Plutonium (Pu) is an anthropogenic radionuclide which has drawn significant attentions due to its radiotoxicity, and the sources of plutonium linked with nuclear accidents and contaminations. The ²⁴⁰Pu/²³⁹Pu atom ratio is source dependent and can be used as a fingerprint to determine the sources of radioactive contaminant. However, the distribution and sources of plutonium in soils of China have not yet been systematically studied at a national scale up to date. The distribution, spatial patterns, and sources of plutonium in soils of China were discussed in this work. The concentrations of ^239,240Pu are in the range of 0.002-4.824 mBq/g with a large variation, and the ^239,240Pu concentrations in surface soils increase with the increasing latitude, which affects by multi-factors such as organic matter and particle size, etc. The inventories of ^239,240Pu are in the range of 7.31-554 Bq/m². The weighted average of ²⁴⁰Pu/²³⁹Pu atom ratios (0.180 ± 0.004) in all surface samples is good agreement with the ratio of global fallout (0.180 ± 0.014) of the nuclear weapons tests, this indicate that the major source of plutonium in China is global fallout. However, among some sites, distinctly lower ²⁴⁰Pu/²³⁹Pu atom ratio compared to the global fallout values were observed in the northwest China, indicating a significant contribution from other source besides the global fallout. Furthermore, the spatial clustering patterns of hot spots (high values) and cold spots (low values) for plutonium showing the clear associations with nuclear tests, especially the Chinese Lop Nor nuclear weapons tests (CNTs) and the Semipalatinsk nuclear weapons tests (STS). Radioactive material including plutonium from the STS or CNTs was transported by the prevailing westerlies to the northwest China. This review about the fingerprints and distribution of plutonium in soils of China will help researchers to establish a reference database for future radiation risk assessment and environmental radioactive management.

Spatio-temporal distribution of 239+240Pu in sediments of the China sea and adjacent waters

Data of ^239+240Pu activities and ²⁴⁰Pu/²³⁹Pu atom ratios in surface and core sediments of the China Sea and adjacent waters were collected. We examine a dataset of ^239+240Pu activities and ²⁴⁰Pu/²³⁹Pu ratios determined from surface sediments at 516 sites and 84 core sediment mainly across the China Sea and adjacent waters. For the first time the spatial distributions of the ^239+240Pu activities, the ²⁴⁰Pu/²³⁹Pu ratios and the Pacific Proving Ground (PPG) fraction in the China Sea and adjacent waters are fully presented at the same time. Four types of typical ^239+240Pu distribution with depth are commonly summarized: non-peak, pseudo single peak, single peak and multi peaks, which are based on the comprehensive analysis of the vertical distribution of ^239+240Pu in 84 sediment cores that had been studied in the China Sea and adjacent waters. Their occurrence probability are ∼15%, ∼4%, ∼67% and ∼11%, respectively. This is the dominant Pu source in seawater which was transported by the North Equatorial Current and Kuroshio Current and its extension into the China Sea and adjacent waters first from east to west, then from south to north. A sea area to the northeast of Taiwan Island and the Okinawa Trough, shows high ^239+240Pu activities and ²⁴⁰Pu/²³⁹Pu atom ratios spatial distribution trends, which are related to the intrusion of the Kuroshio Current carrying ^239+240Pu from the PPG nuclear weapon tests. The used two end-member mixing model suggests that global fallout and PPG close-in fallout are the main sources of Pu in most of the investigate areas. As the ²⁴⁰Pu/²³⁹Pu of global fallout is relatively constant, the change of ²⁴⁰Pu/²³⁹Pu ratios in surface sediments of the China Sea and adjacent waters are mainly controlled by the PPG close-in fallout input.

Sources and Variability of Plutonium in Chinese Soils: A Statistical Perspective with Moving Average

We investigated the different sources and their corresponding impact areas of Pu in Chinese surface soils to illustrate the state-of-the-art of the sources, levels and distributions of 240Pu/239Pu atom ratios as well as 239+240Pu activity concentrations in China. For the first time a moving average strategy in combination with statistical analysis was employed to partition geographic areas in China based on the reported 240Pu/239Pu atom ratio and 239+240Pu concentration data from public literature. During the partitioning, the median (MED) of the dataset was basically employed as a criteria in place of the commonly used arithmetic average (AM). Concisely, three areas were partitioned according to the different influences of Pu from the Lop Nor (LNTS) and Semipalatinsk (STS) test sites and the global fallout. The partitioned Ternary area (80° E–105° E, 35° N–50° N) was supposed to have multiple sources of Pu including the STS and LNTS besides the global fallout, which was characterized with slightly lower 240Pu/239Pu atom ratios (MED = 0.174) as well as elevated 239+240Pu concentrations (MED = 0.416 mBq/g). Meanwhile, the Binary area (35° N–45° N, 100° E–115° E) was considered to have received the extra contribution from the high-yield nuclear tests at the LNTS besides the global fallout, resulting in the highest 240Pu/239Pu atom ratios (MED = 0.200) across China. The remaining area was marked as the Unitary area, where it only received the exclusive contribution of global fallout. Furthermore, through the statistical analysis of the 240Pu/239Pu data in the Unitary area, we recommended a value of 0.186 ± 0.021 (AM ± SD) as a representative or area-specific 240Pu/239Pu atom ratio baseline to characterize the global fallout derived Pu in Chinese soils.

Level, distribution and sources of plutonium in the northeast and north China

Concentrations of ²³⁹Pu and ²⁴⁰Pu in 163 surface soil samples and five soil cores collected from the northeast and north China were analyzed using the radiochemical separation combined with inductively coupled plasma mass spectrometry measurement. The average ²⁴⁰Pu/²³⁹Pu atomic ratios (0.185 ± 0.018) for all surface soil samples indicated that the global fallout is the major source of plutonium in the studied region. The ^239,240Pu concentrations of the surface soil ranged from 0.002 mBq/g to 4.82 mBq/g, lying in the range of the reported results in the areas with similar latitude, except for a few samples. The distribution of ^239,240Pu in this region is controlled by the deposition of plutonium in the atmosphere and its preservation in the soil, which were affects by multi-factors such as topography, climate, utilization of the land and vegetation coverage. The analytical results could be used as the baseline data for the assessment of the impact of nuclear activities in the past and the future.

Contribution of close-in fallout from the French atmospheric tests in inventories of 137Cs, 241Am and plutonium (238, 239, 240) in Gambier Islands (French Polynesia) - Signatures of stratospheric fallout in the Southern Hemisphere

The inventories of ¹³⁷Cs (503 ± 34 Bq.m^-2), ²⁴¹Am (11.3 ± 1.2 Bq.m^-2), ²⁴¹Pu (33.7 ± 3.4 Bq.m^-2), ²³⁸Pu (6.82 ± 0.87 Bq.m^-2) and ^239+240Pu (113.0 ± 5.9 Bq.m^-2), sum of ²³⁹Pu (100 ± 11 Bq.m^-2) and ²⁴⁰Pu (14.5 ± 1.7 Bq.m^-2), in the Gambier archipelago (23°S) of the French Polynesia, are well higher the global fallout at this latitude, in unequal proportions for the different radionuclides. (²⁴⁰Pu/²³⁹Pu)_AR (AR: atomic ratio) of 0.0394 ± 0.0062, and (²⁴¹Pu/²³⁹Pu)_AR of (2.03 ± 0.39)10^-4, confirm that the overwhelmingly dominant source of these radionuclides comes from local fallout during the 1970s of the French atmospheric tests of Moruroa and Fangataufa located nearly 400 km from Gambier. The signatures of the local fallout were deduced from the excess of its inventory in ¹³⁷Cs and from the mixing lines established from the signatures of the global fallout, some of the test sites and the isotopic ratios measured in Gambier. Signatures obtained are 2.0 ± 0.4 for ¹³⁷Cs/^239+240Pu, 0.045 ± 0.008 for ²³⁸Pu/^239+240Pu, 0.031 ± 0.009 for ²⁴¹Am/^239+240Pu, 0.092 ± 0.027 for ²⁴¹Pu/^239+240Pu, 0.0163 ± 0.0049 for (²⁴⁰Pu/²³⁹Pu)_AR, (0.78 ± 0.23)10^-4 for (²⁴¹Pu/²³⁹Pu)_AR. The concordance of the mixing lines of the [(²⁴⁰Pu/²³⁹Pu)_AR, (²⁴¹Pu/²³⁹Pu)_AR] and the linear regression of these ratios measured in the stratosphere (40°S) during the 1970s, indicates that the signatures of the close-in deposition are also those of the stratospheric injections of the French tests. The signatures of stratospheric fallout in the Southern Hemisphere were evaluated by considering that the fission energy of these injections represents 11% and that of the Northern Hemisphere represents 89% and that the isotopic ratios of stratospheric injections remained the same over the period 1970-1974. The activity ratios deducted are 21.9 ± 0.1 in ¹³⁷Cs/^239+240Pu, 0.11 ± 0.05 in ²³⁸Pu/^239+240Pu, 1.03 ± 0.12 in ²⁴¹Pu/^239+240Pu and 0.35 ± 0.04 in ²⁴¹Am/^239+240Pu. The associated atom ratios are 0.157 ± 0.011 for (²⁴⁰Pu/²³⁹Pu)_AR and (8.33 ± 0.48)10^-4 for (²⁴¹Pu/²³⁹Pu)_AR. These signatures appear to be consistent with the results of the inventories at Hiva Oa, located more than 1,000 km north of both French test sites, and with those found in the Australian continent, in regions not impacted by UK-test debris. The proportions of close-in tropospheric fallout from the French tests are about 90% in Gambier. They represent a proportion in the inventories of 40% for the ¹³⁷Cs, 60% for ²⁴¹Am and in the range between 80 and 90% for Pu isotopes.

Cancer Incidence of Finnish Sami in the Light of Exposure to Radioactive Fallout

This article summarizes the results of studies on the exposure of the Finnish Sami people to radioactive fallout and the estimations of the related cancer risk. We also discuss the lifestyle, genetic origin and diet of this population. The Sami people are an indigenous people who live in the northern part of Scandinavia and Finland. The review is based on the available scientific literature of Finnish Sami. The traditional Sami diet, high in animal products, persists in Sami groups still involved in reindeer-herding, but others have adopted the typical diet of western cultures. Studies have consistently shown an overall reduced cancer risk among the Finnish Sami people, except for stomach cancer among the Skolt Sami. Common cancers among the Finnish main population, such as prostate, breast and skin cancer are especially rare among the Finnish Sami. The incidence of cancer among the Finnish Sami are mostly similar to those of the Swedish and Norwegian Sami. To conclude, we observed no effect of radioactive pollution on cancer incidence. The lifestyles and environments of the Sami are changing, and their cancer mortality rate today is similar to that of the majority of the Finnish and western population.

The plutonium isotopes and strontium-90 determination in hot particles by characteristic X-rays

This paper reports the developed non-destructive methods for the plutonium isotopes and strontium-90 content determination in hot particles and other samples. The proposed methods are based on the measurement of the characteristic X-rays accompanying the decay of these radionuclides. For hot particles of NPP accident origin, the proposed method's error limits are 10-15% for hot particles (samples) with activity above 100 Bq and 15-20% for hot particles (samples) with activity less than 100 Bq. For explosive particles, the determination accuracy is 10-15% for activity more than 5 Bq and 20-30% for 0.1-5 Bq activity. The accuracy of the proposed method for determining ⁹⁰Sr in samples with its specific content of more than 10⁴ Bq/sample is 5%, with ~10² Bq/sample its content is 15-20%. The cost of one sample measurement and the processing time of these methods are significantly reduced compared to traditional studies. The proposed methods are reasonably simple measurement methods and can be carried out even in the field condition. They open up new possibilities for the quick search and study of hot particles and environmental samples.

Development of a method for studying 241Pu/241Am activity ratio in the soil of the main Semipalatinsk test site areas

The methodology for determination of ²⁴¹Pu in soils of the main test sites of the Semipalatinsk Test Site (STS) has been developed. The results of ²⁴¹Am and ²⁴¹Pu activity determination in soil samples sampled at the main testing sites of the STS are presented. ²⁴¹Pu/²⁴¹Am activity ratio is calculated. In most cases, on local sites, ²⁴¹Pu/²⁴¹Am activity ratio is in a rather narrow range, which makes it possible to estimate ²⁴¹Pu activity based on the results of ²⁴¹Am gamma-spectrometric analysis. The accuracy of ²⁴¹Pu activity estimation using this method will be about 50%, which is quite enough in most cases.

Anthropogenic radionuclides in Antarctic biota - dosimetrical considerations

The article presents results of the research on artificial radionuclides (¹³⁷Cs, ⁹⁰Sr, ²⁴¹Am) in the Antarctic environment. Samples of 12 species from the marine environment: Pygoscelis adeliae, Pygoscelis papua, Macronectes giganteus, Pagodroma nivea, Catharacta antarctica, Leptonychotes weddellii, Mirounga leonina, Harpagifer antarcticus, Chaenocephalus aceratus, Nacella concinna, Himantothallus grandifolius, Iridaea cordata (bones, feathers, soft tissues, eggs' shells of birds, bones, skin, fur of mammals, fish, mollusks' soft tissues and shells, algae) and samples of 4 species from the terrestrial environment: Sanionia uncinata, Usnea antarctica, Usnea aurantiaco-atra, Deschampsia antarctica (mosses, lichens, grass) were investigated. Differences in the accumulation of ¹³⁷Cs between marine and terrestrial ecosystem were shown, which are mostly due to conservatism of mosses and lichens and active removal of cesium by animal body. Furthermore discrepancy between mosses and lichens in the radioceasium accumulation was statistically proven with the additional use of Neutron Activation Analysis. Moreover, the internal weighted dose rates assessment was prepared using the ERICA Tool. The dose rates were relatively low, not exceeding several dozen nGy/h. Nonetheless, one species - Pagodroma nivea, was significantly outstanding due to the highest weighted dose rate it is burdened with.

Level, distribution and sources of plutonium in the coastal areas of China

Plutonium is an important radioactive element in view of its biological toxicity and environmental impact. The two most important isotopes of plutonium, ²³⁹Pu and ²⁴⁰Pu, in the surface soil from the coastal area of China were determined using radiochemical separation combined with inductively coupled plasma mass spectrometry (ICP-MS) measurement. The average of the measured ²⁴⁰Pu/²³⁹Pu atomic ratios in all these samples is 0.186 ± 0.021, which is in good agreement with the ratio of global fallout of the nuclear weapons tests. This indicates that the major source of plutonium in this region is global fallout, and there is no measurable release of plutonium from any nuclear power plant along the coast of China. The ^239,240Pu concentrations in all 71 soil samples range from 0.002 mBq/g to 0.670 mBq/g, which fall in the range of the reported values in the background area not directly influenced by nuclear activities. The anthropogenic disturbance of sampling sites, vegetation coverage of land, precipitation rate and organic substance content and erosion of soil have significant influence on the level of plutonium in the surface soil.

Variations of plutonium isotopic ratios in Antarctic ecosystems

The aim of the article was to verify the hypothesis concerning the diversification of plutonium sources in the natural environment of Antarctica. Plutonium activity and atom ratios were analyzed in two groups of biological samples: terrestrial and marine. Both isotopic ratios in the terrestrial set were consistent with global radioactive fallout ratios. The average activity ratio in the marine ecosystem was lower than global radioactive fallout. At the same time mass ratio values in this group turned out to be surprisingly varied. Analysis of the results showed statistically significant differences between the marine and terrestrial ecosystems.

Focus on speciation assessment in marine radiochemistry using X-ray absorption spectroscopy

We review the state-of-the-art and recent advances in the determination of radionuclide speciation in seawater.