Montebello Islands marine sediment retains nuclear weapons-derived radionuclide contamination 70years after detonations.

Investigation of the distribution of transuranic radionuclides in marine sediment at the Montebello Islands, Western Australia

This paper provides insights into the radioactivity levels in soils and marine sediments from selected monitoring sites in Singapore. The environmental samples were measured for naturally occurring (e.g., 40K, 238U, 235U, 234U and 232Th) and anthropogenic (e.g., 90Sr, 137Cs, 239Pu and 240Pu) radionuclides. Additionally, the 137Cs activity in surface seawater was analysed. In soil, the decay series of 232Th and 238U are the highest contributors to the total radioactivity, while in sediments, 40K is the main contributor to the total radioactivity. The massic activities of anthropogenic radionuclides in soil (90Sr: 0.24–0.34 Bq kg−1; 137Cs: < 0.3–0.65 Bq kg−1; 239+240Pu: 0.002–0.057 Bq kg−1) and sediment (90Sr: 0.15–0.17 Bq kg−1; 137Cs: < 0.46–0.54 Bq kg−1; 239+240Pu: 0.239–0.294 Bq kg−1), and the activity concentration of 137Cs in seawater (137Cs: 1.1 mBq kg−1), are low and comparable to the values reported for the region. The Pu isotope data demonstrates that the main source of anthropogenic radionuclides in soil (240Pu/239Pu atom ratios: 0.17–0.19) is the global fallout from nuclear weapons testings (NWTs); in sediments (240Pu/239Pu atom ratios: 0.24–0.26), contributions from the Pacific Proving Grounds (PPG) have also been identified. This study also highlights significant differences in radioactivity levels in soils between the northern and central regions of Singapore, which are attributed to soil disturbances in the northern region as a result of intensive anthropogenic activities carried out in the 1980s.

Anthropogenic radionuclide fluxes and distribution in bottom sediments of the cooling basin of the Ignalina Nuclear Power Plant

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

Plutonium and other radionuclides persist across marine-to-terrestrial ecotopes in the Montebello Islands sixty years after nuclear tests.

Sources and distributions of 137Cs, 238Pu, 239,240Pu radionuclides in the north-western Barents Sea

Large volumes of surface seawater samples were collected from thirty locations in the Exclusive Economic Zone (EEZ) of the east coast Peninsular Malaysia on June 2008 to study the activity concentrations of 137Cs. The results will serve as additional information to the existing baseline data and is very useful for monitoring fresh input of anthropogenic radionuclide into Malaysian marine environment. In this study, the activity concentrations of 137Cs were determined using co-precipitation technique, followed by Gamma Spectrometry measurement. The mean activity concentration of 137Cs ranged between 3.40 and 5.89 Bq/m3. Higher activity concentrations were observed at the coastal and towards the south of Peninsular Malaysia and were aligned with the high turbidity. These may due to the rapid diffusion of 137Cs from suspended particulates and fine sediments into surface seawater. The activity concentrations of 137Cs observed in this study were slightly higher than the concentrations reported in seawater at the Straits of Malacca, Vietnam and Philippines. This might be because the study area received more input of 137Cs that originated from global fallout and then deposited on land which later being transported subsequently into the coastal zone due to siltation and erosion processes. It could also be attributed to the intrusion of river waters containing higher concentrations of 137Cs.

Glaciers host complex and dynamic microbial ecosystems that are influenced by anthropogenic contaminants and can be regarded, not only as a considerable pollutant repositories, but also as secondary sources of pollutants. Contaminants such as heavy metals and fallout radionuclides are being brought to glaciers by long-range atmospheric transport and then deposited with wet and dry precipitation. Special attention has been given to cryoconite, debris found on glacier surfaces forming granule-shaped aggregates of minerals and organic matter. Cryoconite is known for its potential for exceptionally high accumulation of radioactive isotopes. Accumulated anthropogenic radionuclides, originating from atmospheric nuclear weapon tests and incidents, can be released back into the environment with sediment and meltwater fluxes and as a melt-out during glacier recession, posing a risk to downstream and proglacial ecosystem health. Many factors contribute to the secondary pollutant release, with climate change and glacier recession playing an increasingly important role in recent decades. Mittivakkat Gletsjer, a peripheral glacier located on Ammassalik Island in Southeast Greenland, shows significant volume and area losses, and although being one of Greenland&amp;#8217;s most extensively explored glaciers, little is known about the radioactive pollution presence and its possible sources. This is true not only for Mittivakkat Gletsjer but for glaciers in Greenland in general. Cryoconite samples were collected from the glacier surface of Mittivakkat Gletsjer in August 2022 and activity concentrations of 238Pu,&amp;#160;239+240Pu, 241Am, 137Cs and 210Pb were measured (up to 1.44Bq/kg, 28.5Bq/kg, 14.4Bq/kg, 1100Bq/kg, 2900Bq/kg, respectively). Obtained values are higher than other environmental matrices (soils, mosses, lichens) indicating high radionuclide accumulation in cryoconite. Radioactive contamination sources were identified by determining the isotope ratios 238Pu/239+240Pu, 239+240Pu/137Cs and 241Am/239+240Pu (0.0514&amp;#177;0.0071, 0.0251&amp;#177;0.0044, 0.54&amp;#177;0.12). The results suggest that global fallout, an aftermath of atmospheric nuclear weapon tests, is likely the main source of radioactive pollution at Mittivakkat Gletsjer. A two-sources model (global fallout and Chernobyl incident) shows that global fallout is responsible for 92% of plutonium and 62% of cesium in the measured samples. High correlations (r2&gt;0.75) between sample altitude and 238Pu, 239+240Pu, 241Am, 137Cs activity concentrations have been found. Samples collected from higher elevation accumulated more radionuclides, a relationship also observed at other glaciers. The same is not true for 210Pb for which a very weak correlation (r20.7) and weaker for 137Cs and 210Pb (r2

Radioactivity exploration from the Arctic to the Antarctic. Part 3. The SWEDARP expedition Oct 1988 – April 1989

&amp;lt;p&amp;gt;Radioactive cesium (&amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs) is distributed in the global ocean due to global fallout by atmospheric nuclear weapons tests, releases from reprocessing plants in Europe, and supplied to the ocean by the Fukushima Daiichi Nuclear Power Plant (1F NPP) accident. In order to detect future contamination by radionuclides, it is necessary to understand the global distribution of radionuclides such as &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs. For this purpose, observed data have been summarized in a historical database (MARIS) by IAEA. The spatio-temporal density of the observations varies widely, therefore simulation by an ocean general circulation model (OGCM) can be helpful in the interpretation of these observations.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In order to clarify the behavior of &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs in the global ocean, OGSM simulations were conducted. Parallel Ocean Program version 2 (POP2) of the Community Earth System Model version 2 (CESM2) is employed. The horizontal resolution is 1.125 degree of longitude, and from 0.28 degree to 0.54 degree of latitude. There are 60 vertical levels with a minimum spacing of 10 m near the ocean surface, and increased spacing with depth to a maximum of 250 m. The simulated period was from 1945 to 2030 with the circulation forced by repeating (&amp;amp;#8220;Normal Year&amp;amp;#8221;) atmospheric conditions. As input sources of &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs to the model, global fallout from atmospheric nuclear tests, releases from reprocessing plants in Europe, and input from the 1F NPP accident were considered. It was assumed that the input conditions in 2020 would continue after 2020.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The simulated &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs activity agrees well with the observed data in the database, especially in the Atlantic and Pacific Oceans where the observation density is large. Since &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs undergoes radioactive decay with a half-life of 30 years, the inventory for each basin is the difference between the decay corrected cumulative input and flux. In the North Pacific, the inventory reached its maximum in 1966 due to the global fallout by atmospheric nuclear weapons tests. Fluxes from the North Pacific to the Indian Ocean, Arctic Ocean, and Central Pacific were positive, and the North Pacific was a source of supply for other ocean basins. The 1F NPP accident caused a 20% increase in the inventory in 2011. In the North Atlantic, the inventory reaches its maximum in the late 1970s, due to the releases from the reprocessing plant. The outflow flux from the North Atlantic to the Greenland Sea is larger than the other fluxes and is a source of supply to other ocean basins. After 2000, the inflow flux to the North Pacific from the Labrador Sea and the South Atlantic is larger than the outflow flux.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The time series of &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs inventory in each ocean basin and the fluxes among ocean basins were quantitatively analyzed by OGCM simulations, and the predictions for the next 10 years were made.&amp;amp;#160; The &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs activity concentrations by global fallout can be detected in the global ocean after 2030. The OGCM simulations will be useful in planning future observations to fill the gaps in the database.&amp;lt;/p&amp;gt;

Determination of plutonium in cryoconite on glacier surfaces in the northeast Tibetan Plateau: Implications for source identification and accumulation

Distribution of 239,240Pu and 238Pu concentrations in sediments from the Ob and Yenisey Rivers and the Kara Sea

Background: This study was a long-term evaluation of 137Cs and 90Sr activity concentrations in seawater samples from the East Sea, Korea, in order to establish current activity levels. Results and long-term monitoring trends will be useful in the future monitoring of environmental radioactivity. Materials and Methods: Surface seawater samples were collected quarterly from Guryongpo and Jangho in the East Coast between 1998 and 2010 and the quarterly deep seawater samples were collected from three sites in the sea adjacent to Ulleung-do between 2012 and 2015. The activity concentrations of 137Cs were measured using a gamma-spectrometer. The activity concentrations of 90Sr and 90Y in a radioactive equilibrium state were measured using a gas flow proportional counter. Results and Discussion: We found the annual average activity concentrations of 137Cs in the surface seawater was 1.66-2.89 mBq∙kg-1 in Guryongpo and 1.68-2.43 mBq∙kg-1 in Jangho. The annual average activity concentrations of 90Sr in the surface seawater was 0.83- 1.98 mBq∙kg-1 in Guryongpo and 0.82-1.57 mBq∙kg-1 in Jangho. The annual average activity concentrations of 137Cs in the deep seawater sites were 1.51-1.73 mBq∙kg-1, 1.19-1.60 mBq∙kg-1 and 0.87-1.15 mBq∙kg-1 in TH, JD, and HP. The annual average activity concentrations of 90Sr in the same deep seawater sites were 1.00-1.94 mBq∙kg-1, 0.82-1.26 mBq∙kg-1, and 0.79-1.32 mBq∙kg-1. The effective half-life was calculated by analyzing change over time in the activity concentration in the surface seawater. The effective half-life of 137Cs was 15.3 ± 0.1 years in Guryongpo and 102 ± 3 years in Jangho. The effective half-life of 90Sr was 28.3 ± 4.3 years in Guryongpo and 16.6 ± 0.1 years in Jangho. The ratio of the average activity concentration (137Cs/90Sr) was 1.72 in the surface seawater, which is similar to the reported ratio of the global radioactive fallout. The ratio in the deep seawater was 1.24, which is somewhat low compared to the global ratio (1.6, 1.8). Conclusion: Activity concentrations of 137Cs and 90Sr in the seawaters of the East Sea were similar to the previously reported activity levels in the East Sea and northwestern Pacific as a result of global radioactive fallout following atmospheric nuclear weapon tests.

Vertical distributions and source identification of the radionuclides 239Pu and 240Pu in the sediments of the Liao River estuary, China

Research progress on the distribution of anthropogenic radionuclides in Northwest China.