1
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Ang JWL, Bongrand A, Duval S, Donnard J, Jolis EM, Utsunomiya S, Minomo K, Koivula R, Siitari-Kauppi M, Law GTW. Detecting radioactive particles in complex environmental samples using real-time autoradiography. Sci Rep 2024; 14:5413. [PMID: 38443397 PMCID: PMC10915129 DOI: 10.1038/s41598-024-52876-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
Radioactive particles often contain very high radioactivity concentrations and are widespread. They pose a potential risk to human health and the environment. Their detection, quantification, and characterization are crucial if we are to understand their impact. Here, we present the use of a real-time autoradiography gaseous detector (using parallel ionization multiplier) to expedite and improve the accuracy of radioactive particle screening in complex environmental samples. First, standard particles were used to assess the detector capabilities (spatial resolution, spectrometry, and artefact contributions), then, we applied the technique to more complex and environmentally relevant samples. The real-time autoradiography technique provides data with a spatial resolution (≲100 µm) suitable for particle analysis in complex samples. Further, it can differentiate between particles predominantly emitting alpha and beta radiation. Here, the technique is applied to radioactive cesium-rich microparticles collected from the Fukushima Daiichi nuclear exclusion zone, showing their accurate detection, and demonstrating the viability of real-time autoradiography in environmental scenarios. Indeed, for more complex samples (radioactive particles in a less radioactive heterogeneous background mix of minerals), the technique permits relatively high selectivity for radioactive particle screening (up to 61.2% success rate) with low false positive percentages (~ 1%).
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Affiliation(s)
- Joyce W L Ang
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
- Singapore Nuclear Safety and Research Initiative, National University of Singapore, Singapore, 138602, Singapore.
| | - Arthur Bongrand
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
- IMT Atlantique, Nantes Université, CNRS, 44000, Nantes, SUBATECH, France
| | - Samuel Duval
- AI4R, 2 Rue Alfred Kastler, 44307, Nantes, France
| | | | - Ester M Jolis
- Circular Economy Solutions Research Laboratory, Geological Survey of Finland GTK, 02151, Espoo, Finland
| | - Satoshi Utsunomiya
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Kenta Minomo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka, 819-0395, Japan
| | - Risto Koivula
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Marja Siitari-Kauppi
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland
| | - Gareth T W Law
- Department of Chemistry, Radiochemistry Unit, The University of Helsinki, 00014, Helsinki, Finland.
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2
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Johansen MP, Child DP, Collins R, Cook M, Davis J, Hotchkis MAC, Howard DL, Howell N, Ikeda-Ohno A, Young E. Radioactive particles from a range of past nuclear events: Challenges posed by highly varied structure and composition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156755. [PMID: 35718169 DOI: 10.1016/j.scitotenv.2022.156755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
| | - David P Child
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | | | - Megan Cook
- International Atomic Energy Agency (IAEA), Environmental Laboratories, Monaco
| | - Joel Davis
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Michael A C Hotchkis
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Daryl L Howard
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Nicholas Howell
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Atsushi Ikeda-Ohno
- Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan
| | - Emma Young
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
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3
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Harrison JJ, Saunders KM, Child DP, Hotchkis MAC. A record of fallout 239Pu and 240Pu at World Heritage Bathurst Harbour, Tasmania, Australia. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 237:106679. [PMID: 34118615 DOI: 10.1016/j.jenvrad.2021.106679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 05/21/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
This study presents the first measurements of anthropogenic plutonium (239Pu and 240Pu) concentrations and atom ratios (240Pu/239Pu) for Tasmania, in sediment collected from Bathurst Harbour, in the Tasmanian Wilderness World Heritage Area, Australia. The weighted mean 240Pu/239Pu atom ratio measured at this site was 0.172 ± 0.007 which is consistent with published data from mainland Australia and global and Southern Hemisphere averages. The 240Pu/239Pu atom ratios ranged between 0.11 and 0.21 with the earliest recorded 240Pu/239Pu atom ratios being the lowest, suggesting an influence of low atom ratio fallout from nuclear testing in Australia. Post-moratorium fallout 240Pu/239Pu atom ratios were consistent with other records. Lead-210 (210Pb) sediment chronologies indicate sediment accumulation rates have increased since the early part of the 19th century at this location.
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Affiliation(s)
- Jennifer J Harrison
- ANSTO, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia.
| | - Krystyna M Saunders
- ANSTO, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia.
| | - David P Child
- ANSTO, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia.
| | - Michael A C Hotchkis
- ANSTO, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, New South Wales, 2234, Australia.
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4
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Cook M, Etschmann B, Ram R, Ignatyev K, Gervinskas G, Conradson SD, Cumberland S, Wong VNL, Brugger J. The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia. Sci Rep 2021; 11:10698. [PMID: 34021195 PMCID: PMC8139974 DOI: 10.1038/s41598-021-89757-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 04/20/2021] [Indexed: 11/15/2022] Open
Abstract
The high-energy release of plutonium (Pu) and uranium (U) during the Maralinga nuclear trials (1955–1963) in Australia, designed to simulate high temperature, non-critical nuclear accidents, resulted in wide dispersion µm-sized, radioactive, Pu–U-bearing ‘hot’ particles that persist in soils. By combining non-destructive, multi-technique synchrotron-based micro-characterization with the first nano-scale imagining of the composition and textures of six Maralinga particles, we find that all particles display intricate physical and chemical make-ups consistent with formation via condensation and cooling of polymetallic melts (immiscible Fe–Al–Pu–U; and Pb ± Pu–U) within the detonation plumes. Plutonium and U are present predominantly in micro- to nano-particulate forms, and most hot particles contain low valence Pu–U–C compounds; these chemically reactive phases are protected by their inclusion in metallic alloys. Plutonium reworking was observed within an oxidised rim in a Pb-rich particle; however overall Pu remained immobile in the studied particles, while small-scale oxidation and mobility of U is widespread. It is notoriously difficult to predict the long-term environmental behaviour of hot particles. Nano-scale characterization of the hot particles suggests that long-term, slow release of Pu from the hot particles may take place via a range of chemical and physical processes, likely contributing to on-going Pu uptake by wildlife at Maralinga.
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Affiliation(s)
- Megan Cook
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Australia
| | - Barbara Etschmann
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Australia.
| | - Rahul Ram
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Australia
| | - Konstantin Ignatyev
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxon, OX11 0QX, United Kingdom
| | - Gediminas Gervinskas
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Australia
| | - Steven D Conradson
- Department of Chemistry, Washington State University, Pullman, WA, USA.,Department of Complex Matter, Josef Stefan Institute, Ljubljana, Slovenia
| | | | - Vanessa N L Wong
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Australia
| | - Joёl Brugger
- School of Earth, Atmosphere and Environment, Monash University, Clayton, Australia.
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5
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Johansen MP, Anderson D, Child D, Hotchkis MAC, Tsukada H, Okuda K, Hinton TG. Differentiating Fukushima and Nagasaki plutonium from global fallout using 241Pu/ 239Pu atom ratios: Pu vs. Cs uptake and dose to biota. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:141890. [PMID: 32916482 DOI: 10.1016/j.scitotenv.2020.141890] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Plutonium (Pu) has been released in Japan by two very different types of nuclear events - the 2011 Fukushima accident and the 1945 detonation of a Pu-core weapon at Nagasaki. Here we report on the use of Accelerator Mass Spectrometry (AMS) methods to distinguish the FDNPP-accident and Nagasaki-detonation Pu from worldwide fallout in soils and biota. The FDNPP-Pu was distinct in local environmental samples through the use of highly sensitive 241Pu/239Pu atom ratios. In contrast, other typically-used Pu measures (240Pu/239Pu atom ratios, activity concentrations) did not distinguish the FDNPP Pu from background in most 2016 environmental samples. Results indicate the accident contributed new Pu of ~0.4%-2% in the 0-5 cm soils, ~0.3%-3% in earthworms, and ~1%-10% in wild boar near the FDNPP. The uptake of Pu in the boar appears to be relatively uninfluenced by the glassy particle forms of fallout near the FDNPP, whereas the 134,137Cs uptake appears to be highly influenced. Near Nagasaki, the lasting legacy of Pu is greater with high percentages of Pu sourced from the 1945 detonation (~93% soils, ~88% earthworm, ~96% boar). The Pu at Nagasaki contrasts with that from the FDNPP in having proportionately higher 239Pu and was distinguished by both 240Pu/239Pu and 241Pu/239Pu atom ratios. However, compared with the contamination near the Chernobyl accident site, the Pu amounts at all study sites in Japan are orders of magnitude lower. The dose rates from Pu to organisms in the FDNPP and Nagasaki areas, as well as to human consumers of wild boar meat, have been only slightly elevated above background. Our data demonstrate the greater sensitivity of 241Pu/239Pu atom ratios in tracing Pu from nuclear releases and suggest that the Nagasaki-detonation Pu will be distinguishable in the environment for much longer than the FDNPP-accident Pu.
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Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation, Sydney, Australia.
| | - Donovan Anderson
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan; Symbiotic Systems Science and Technology, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan
| | - David Child
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | | | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan
| | - Kei Okuda
- Faculty of Human Environmental Studies, Hiroshima Shudo University, 731-3195, Hiroshima Prefecture, Asaminami-ku, Ozuka-higashi, Japan
| | - Thomas G Hinton
- Institute of Environmental Radioactivity, Fukushima University, 960-1248, Fukushima Prefecture, Fukushima, Kanayagawa, Japan; CERAD CoE, Norwegian University of Life sciences, Faculty for Environmental Sciences and Nature Research Management, Aas, Norway
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6
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Baigazinov ZА, Lukashenko SN, Panitsky АV, Kadyrova NZ, Karatayev SS, Mamyrbayeva АS, Baigazy SА, Bazarbaeva АМ, Kabdyrakova AB, Kunduzbaeva АE, Kenzhina LB, Zhadyranova AA, Hegedus M, Kovacs T. The transfer of 239+240Pu, 241Am, 137Cs and 90Sr to the tissues of horses. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 222:106322. [PMID: 32565415 DOI: 10.1016/j.jenvrad.2020.106322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Horses are important food sources in several countries however, data on their radionuclide uptake is less available than for many other farm animals. Information on the transfer of artificial radioisotopes from the environment to the food supply is necessary for internal dose assessment and assuring the safety of the population relying on this food source. This study provides data for a less studied farm animal and, in the case of 241Am and 239+240Pu, relatively poorly studied radionuclides with respect to transfer to animal products. The transfer parameters for 239+240Pu, 241Am, 137Cs and 90Sr to the organs of 1-year old fillies, 10-year old mares and through the placental barrier into foetuses were quantified after 60-days feeding with contaminated soil or diet contaminated by a leachate solution. The transfer of radionuclides from ingested soil to tissues was generally lower, by up to three orders of magnitude, than from a diet contaminated by a leachate solution. The ingestion of soil is a particularly important source of radionuclide intake to grazing animals in the Semipalatinsk Test Site. For 241Am there is a lack of available data, the two singular entries for mutton and beef in the IAEA handbook are higher than all values observed in the current study. The maximum observed transfer factor for 241Am was 72 ± 22*10-5 d kg-1 FW in the liver of the mare fed with leachate contaminated feed. For 239+240Pu the maximum transfer factor was 31.8 ± 8*10-5 d kg-1 FW observed also in the liver of the mare fed with leachate contaminated feed. The filly fed with leachate contaminated feed had the highest transfer parameter value for 137Cs, 35.3*10-3 d kg-1 FW. The highest 90Sr transfer factor was found in the ribs of the filly fed leachate contaminated feed, 720 ± 144 *10-3 d kg-1 FW. The results presented in this paper can be used to improve the current internal dose estimates from the ingestion of horse meat produced in the area, however they are based on a low sample size; future studies need to use a larger number of animals.
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Affiliation(s)
- Zh А Baigazinov
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan; University of Pannonia, Veszprem, Hungary.
| | - S N Lukashenko
- Russian Institute of Radiology and Agroecology, Obninsk, Russian Federation
| | - А V Panitsky
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - N Zh Kadyrova
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - S S Karatayev
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - А S Mamyrbayeva
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - S А Baigazy
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - А М Bazarbaeva
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - A B Kabdyrakova
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - А E Kunduzbaeva
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - L B Kenzhina
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - A A Zhadyranova
- Institute of Radiation Safety and Ecology, Kurchatov, Kazakhstan
| | - M Hegedus
- University of Pannonia, Veszprem, Hungary
| | - T Kovacs
- University of Pannonia, Veszprem, Hungary.
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7
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Johansen MP, Child DP, Hotchkis MAC, Johansen A, Thiruvoth S, Whiting SD. Radionuclides in sea turtles at the Montebello Islands former nuclear test sites: Current and historical dose rates for adults and embryos. MARINE POLLUTION BULLETIN 2020; 158:111390. [PMID: 32753176 DOI: 10.1016/j.marpolbul.2020.111390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Radionuclides from 1950s weapons testing at the Montebello Islands, Western Australia, may impact sea turtle embryos incubating within eggs laid in contaminated sands or be taken up into adult body tissues where they can contribute to radiation dose over a turtles' 60+ year lifespan. We measured plutonium in all local samples including turtle skin, bones, hatchlings, eggshells, sea sediments, diet items and beach sands. The amount of Pu in developing embryos/hatchling samples was orders of magnitude lower than that in the surrounding sands. These contaminated sands caused most dose to eggs (external dose from 137Cs, 152Eu), while most of the dose to adults was from internalised radionuclides (98%). While current dose rates are relatively low, local dose rates were high for about ten years following the 1950s detonations and may have resulted in lethality or health impacts to a generation of turtles that likely carry biomarkers today.
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Affiliation(s)
- Mathew P Johansen
- Australian Nuclear Science and Technology Organisation, Sydney, Australia.
| | - David P Child
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | | | - Andrea Johansen
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Sangeeth Thiruvoth
- Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Scott D Whiting
- Western Australia Department of Biodiversity Conservation and Attractions, Kensington, Australia
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8
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Johansen MP, Child DP, Cresswell T, Harrison JJ, Hotchkis MAC, Howell NR, Johansen A, Sdraulig S, Thiruvoth S, Young E, Whiting SD. Plutonium and other radionuclides persist across marine-to-terrestrial ecotopes in the Montebello Islands sixty years after nuclear tests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 691:572-583. [PMID: 31325857 DOI: 10.1016/j.scitotenv.2019.06.531] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/29/2019] [Accepted: 06/30/2019] [Indexed: 06/10/2023]
Abstract
Since the 1956 completion of nuclear testing at the Montebello Islands, Western Australia, this remote uninhabited island group has been relatively undisturbed (no major remediations) and currently functions as high-value marine and terrestrial habitat within the Montebello/Barrow Islands Marine Conservation Reserves. The former weapons testing sites, therefore, provide a unique opportunity for assessing the fate and behaviour of Anthropocene radionuclides subjected to natural processes across a range of shallow-marine to island-terrestrial ecological units (ecotopes). We collected soil, sediment and biota samples and analysed their radionuclide content using gamma and alpha spectrometry, photostimulated luminescence autoradiography and accelerator mass spectrometry. We found the activity levels of the fission and neutron-activation products have decreased by ~hundred-fold near the ground zero locations. However, Pu concentrations remain elevated, some of which are high relative to most other Australian and international sites (up to 25,050 Bq kg-1 of 239+240+241Pu). Across ecotopes, Pu ranked from highest to lowest in the following order: island soils > dunes > foredunes > marine sediments > and beach intertidal zone. Low values of Pu and other radionuclides were detected in all local wildlife tested including endangered species. Activity concentrations ranked (highest to lowest) terrestrial arthropods > terrestrial mammal and reptile bones > algae > oyster flesh > whole crab > sea turtle bone > stingray and teleost fish livers > sea cucumber flesh > sea turtle skin > teleost fish muscle. The three detonations (one from within a ship and two from 30 m towers) resulted in differing contaminant forms, with the ship detonation producing the highest activity concentrations and finer more inhalable particulate forms. The three sites are distinct in their 240/239Pu and 241/239Pu atom ratios, including the Pu transported by natural process or within migratory living organisms.
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Affiliation(s)
| | | | | | | | | | | | | | - S Sdraulig
- Australian Radiation Protection and Nuclear Safety Agency, Yallambie, Australia
| | | | | | - S D Whiting
- Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
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9
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Salbu B, Kashparov V, Lind OC, Garcia-Tenorio R, Johansen MP, Child DP, Roos P, Sancho C. Challenges associated with the behaviour of radioactive particles in the environment. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 186:101-115. [PMID: 28941957 DOI: 10.1016/j.jenvrad.2017.09.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 06/07/2023]
Abstract
A series of different nuclear sources associated with the nuclear weapon and fuel cycles have contributed to the release of radioactive particles to the environment. Following nuclear weapon tests, safety tests, conventional destruction of weapons, reactor explosions and fires, a major fraction of released refractory radionuclides such as uranium (U) and plutonium (Pu) were present as entities ranging from sub microns to fragments. Furthermore, radioactive particles and colloids have been released from reprocessing facilities and civil reactors, from radioactive waste dumped at sea, and from NORM sites. Thus, whenever refractory radionuclides are released to the environment following nuclear events, radioactive particles should be expected. Results from many years of research have shown that particle characteristics such as elemental composition depend on the source, while characteristics such as particle size distribution, structure, and oxidation state influencing ecosystem transfer depend also on the release scenarios. When radioactive particles are deposited in the environment, weathering processes occur and associated radionuclides are subsequently mobilized, changing the apparent Kd. Thus, particles retained in soils or sediments are unevenly distributed, and dissolution of radionuclides from particles may be partial. For areas affected by particle contamination, the inventories can therefore be underestimated, and impact and risk assessments may suffer from unacceptable large uncertainties if radioactive particles are ignored. To integrate radioactive particles into environmental impact assessments, key challenges include the linking of particle characteristics to specific sources, to ecosystem transfer, and to uptake and retention in biological systems. To elucidate these issues, the EC-funded COMET and RATE projects and the IAEA Coordinated Research Program on particles have revisited selected contaminated sites and archive samples. This COMET position paper summarizes new knowledge on key sources that have contributed to particle releases, including particle characteristics based on advanced techniques, with emphasis on particle weathering processes as well as on heterogeneities in biological samples to evaluate potential uptake and retention of radioactive particles.
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Affiliation(s)
- Brit Salbu
- CERAD CoE Environmental Radioactivity, Faculty of Environmental Sciences and Nature Resource Management, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway.
| | - Valery Kashparov
- CERAD CoE Environmental Radioactivity, Faculty of Environmental Sciences and Nature Resource Management, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway; National University of Life and Environmental Sciences of Ukraine (NUBiP of Ukraine), Ukraine
| | - Ole Christian Lind
- CERAD CoE Environmental Radioactivity, Faculty of Environmental Sciences and Nature Resource Management, Norwegian University of Life Sciences (NMBU), 1432 Aas, Norway
| | | | - Mathew P Johansen
- Australian Nuclear Science and Technology Organization (ANSTO), Australia
| | - David P Child
- Australian Nuclear Science and Technology Organization (ANSTO), Australia
| | - Per Roos
- Technical University of Denmark (DTU), Denmark
| | - Carlos Sancho
- Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Spain
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10
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Hirth GA, Grzechnik M, Tinker R, Larsson CM. Australia's proactive approach to radiation protection of the environment: how integrated is it with radiation protection of humans? Ann ICRP 2018; 47:313-326. [PMID: 29699413 DOI: 10.1177/0146645318756842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Australia's regulatory framework has evolved over the past decade from the assumption that protection of humans implies protection of the environment to the situation now where radiological impacts on non-human species (wildlife) are considered in their own right. In an Australian context, there was a recognised need for specific national guidance on protection of non-human species, for which the uranium mining industry provides the major backdrop. National guidance supported by publications of the Australian Radiation Protection and Nuclear Safety Agency (Radiation Protection Series) provides clear and consistent advice to operators and regulators on protection of non-human species, including advice on specific assessment methods and models, and how these might be applied in an Australian context. These approaches and the supporting assessment tools provide a mechanism for industry to assess and demonstrate compliance with the environmental protection objectives of relevant legislation, and to meet stakeholder expectations that radiological protection of the environment is taken into consideration in accordance with international best practice. Experiences from the past 5-10 years, and examples of where the approach to radiation protection of the environment has been well integrated or presented some challenges will be discussed. Future challenges in addressing protection of the environment in existing exposure situations will also be discussed.
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Affiliation(s)
- G A Hirth
- Australian Radiation Protection and Nuclear Safety Agency, 619 Lower Plenty Rd, Yallambie, 3085 Victoria, Australia
| | - M Grzechnik
- Australian Radiation Protection and Nuclear Safety Agency, 619 Lower Plenty Rd, Yallambie, 3085 Victoria, Australia
| | - R Tinker
- Australian Radiation Protection and Nuclear Safety Agency, 619 Lower Plenty Rd, Yallambie, 3085 Victoria, Australia
| | - C M Larsson
- Australian Radiation Protection and Nuclear Safety Agency, 619 Lower Plenty Rd, Yallambie, 3085 Victoria, Australia
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11
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Hirth GA, Johansen MP, Carpenter JG, Bollhöfer A, Beresford NA. Whole-organism concentration ratios in wildlife inhabiting Australian uranium mining environments. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 178-179:385-393. [PMID: 28457640 DOI: 10.1016/j.jenvrad.2017.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/12/2017] [Accepted: 04/10/2017] [Indexed: 06/07/2023]
Abstract
Wildlife concentration ratios for 226Ra, 210Pb, 210Po and isotopes of Th and U from soil, water, and sediments were evaluated for a range of Australian uranium mining environments. Whole-organism concentration ratios (CRwo-media) were developed for 271 radionuclide-organism pairs within the terrestrial and freshwater wildlife groups. Australian wildlife often has distinct physiological attributes, such as the lower metabolic rates of macropod marsupials as compared with placental mammals. In addition, the Australian CRswo-media originate from tropical and semi-arid climates, rather than from the temperate-dominated climates of Europe and North America from which most (>90%) of internationally available CRwo-media values originate. When compared, the Australian and non-Australian CRs are significantly different for some wildlife categories (e.g. grasses, mammals) but not others (e.g. shrubs). Where differences exist, the Australian values were higher, suggesting that site-, or region-specific CRswo-media should be used in detailed Australian assessments. However, in screening studies, use of the international mean values in the Wildlife Transfer Database (WTD) appears to be appropriate, as long as the values used encompass the Australian 95th percentile values. Gaps in the Australian datasets include a lack of marine parameters, and no CR data are available for freshwater phytoplankton, zooplankton, insects, insect larvae or amphibians; for terrestrial environments, there are no data for amphibians, annelids, ferns, fungi or lichens & bryophytes. The new Australian specific parameters will aide in evaluating remediation plans and ongoing operations at mining and waste sites within Australia. They have also substantially bolstered the body of U- and Th-series CRwo-media data for use internationally.
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Affiliation(s)
- Gillian A Hirth
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), 619 Lower Plenty Rd, Yallambie, 3085, Victoria, Australia.
| | - Mathew P Johansen
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee, DC, NSW 2232, Australia
| | - Julia G Carpenter
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), 619 Lower Plenty Rd, Yallambie, 3085, Victoria, Australia
| | - Andreas Bollhöfer
- Environmental Research Institute of the Supervising Scientist, GPO Box 461, Darwin, 0801 Northern Territory, Australia
| | - Nicholas A Beresford
- Natural Environment Research Council - Centre for Ecology & Hydrology, Bailrigg, Lancaster LA1 4AP, United Kingdom
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Caffrey E, Johansen M, Caffrey J, Higley K. Comparison of Homogeneous and Particulate Lung Dose Rates For Small Mammals. HEALTH PHYSICS 2017; 112:526-532. [PMID: 28441284 DOI: 10.1097/hp.0000000000000668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Small, highly radioactive fragments of material incorporated into metallic matrices are commonly found at nuclear weapons test and accident sites and can be inhaled by wildlife. Inhaled particles often partition heterogeneously in the lungs, with aggregation occurring in the periphery of the lung, and are tenaciously retained. However, dose rates are typically calculated as if the material were homogeneously distributed throughout the entire organ. Here the authors quantify the variation in dose rates for alpha-, beta-, and gamma-emitting radionuclides with particle sizes from 0.01-150 μm (alpha) and 1-150 μm (beta, gamma) and considering three averaging volumes-the entire lung (64 cm), a 10-cm volume of tissue, and a 1-cm volume of tissue. Dose rates from beta-emitting particles (e.g., Sr) were approximately one order of magnitude higher than those from gamma-emitting radionuclides (e.g., Cs). Self-shielding within the particle, which reduces the dose rate to the surrounding tissue, was negligible for gammas and minor for betas. For alpha-emitting particles (e.g., Pu), self-shielding in larger particles is substantial, with >90% of emissions captured within particles of +20 μm diameter; but for smaller sizes of the respirable range of 0.01 to 5 μm, an average of 85% of the energy escapes the particle and is deposited in the surrounding tissues. These data provide more detail on respirable particles, which may remain lodged deep in the lung where they represent a considerable contribution to long-term lung dose rates. For practical dose rate calculation purposes, a graph of particle size vs. dose rates for plutonium-containing hot particles is provided. This study demonstrates one possible approach to dose assessments for biota in environments contaminated by radioactive particles, which may prove useful for those engaged in environmental radioprotection.
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Affiliation(s)
- Emily Caffrey
- *Oregon State University, School of Nuclear Science and Engineering, 151 Batcheller Hall, Corvallis, OR 97331 (affiliation when work was performed); †Australian Nuclear Science and Technology Organisation, Kirrawee, Australia
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Ikeda-Ohno A, Shahin LM, Howard DL, Collins RN, Payne TE, Johansen MP. Fate of Plutonium at a Former Nuclear Testing Site in Australia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9098-9104. [PMID: 27548999 DOI: 10.1021/acs.est.6b01864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A series of the British nuclear tests conducted on mainland Australia between 1953 and 1963 dispersed long-lived radioactivity and nuclear weapons debris including plutonium (Pu), the legacy of which is a long-lasting source of radioactive contamination to the surrounding biosphere. A reliable assessment of the environmental impact of Pu contaminants and their implications for human health requires an understanding of their physical/chemical characteristics at the molecular scale. In this study, we identify the chemical form of the Pu remaining in the local soils at the Taranaki site, one of the former nuclear testing sites at Maralinga, South Australia. We herein reveal direct spectroscopic evidence that the Pu legacy remaining at the site exists as particulates of Pu(IV) oxyhydroxide compounds, a very concentrated and low-soluble form of Pu, which will serve as ongoing radioactive sources far into the future. Gamma-ray spectrometry and X-ray fluorescence analysis on a collected Pu particle indicate that the Pu in the particle originated in the so-called "Minor trials" that involved the dispersal of weapon components by highly explosive chemicals, not in the nuclear explosion tests called "Major trials". A comprehensive analysis of the data acquired from X-ray fluorescence mapping (XFM), X-ray absorption near-edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) suggests that the collected Pu particle forms a "core-shell" structure with the Pu(IV) oxyhydroxide core surrounded by an external layer containing Ca, Fe, and U, which further helps us to deduce a possible scenario of the physical/chemical transformation of the original Pu materials dispersed in the semiarid environment at Maralinga more than 50 years ago. These findings also highlight the importance of the comprehensive physical/chemical characterization of Pu contaminants for reliable environmental- and radiotoxicological assessment.
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Affiliation(s)
- Atsushi Ikeda-Ohno
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology , Bautzner Landstrasse 400, 01328 Dresden, Germany
- Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Lida Mokhber Shahin
- Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Daryl L Howard
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Richard N Collins
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Timothy E Payne
- Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Mathew P Johansen
- Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
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Caffrey EA, Johansen MP, Higley KA. Voxel modeling of rabbits for use in radiological dose rate calculations. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 2:480-486. [PMID: 25971772 DOI: 10.1016/j.jenvrad.2015.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/02/2015] [Accepted: 04/14/2015] [Indexed: 06/04/2023]
Abstract
Radiation dose to biota is generally calculated using Monte Carlo simulations of whole body ellipsoids with homogeneously distributed radioactivity throughout. More complex anatomical phantoms, termed voxel phantoms, have been developed to test the validity of these simplistic geometric models. In most voxel models created to date, human tissue composition and density values have been used in lieu of biologically accurate values for non-human biota. This has raised questions regarding variable tissue composition and density effects on the fraction of radioactive emission energy absorbed within tissues (e.g. the absorbed fraction - AF), along with implications for age-dependent dose rates as organisms mature. The results of this study on rabbits indicates that the variation in composition between two mammalian tissue types (e.g. human vs rabbit bones) made little difference in self-AF (SAF) values (within 5% over most energy ranges). However, variable tissue density (e.g. bone vs liver) can significantly impact SAF values. An examination of differences across life-stages revealed increasing SAF with testis and ovary size of over an order of magnitude for photons and several factors for electrons, indicating the potential for increasing dose rates to these sensitive organs as animals mature. AFs for electron energies of 0.1, 0.2, 0.4, 0.5, 0.7, 1.0, 1.5, 2.0, and 4.0 MeV and photon energies of 0.01, 0.015, 0.02, 0.03, 0.05, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, and 4.0 MeV are provided for eleven rabbit tissues. The data presented in this study can be used to calculate accurate organ dose rates for rabbits and other small rodents; to aide in extending dose results among different mammal species; and to validate the use of ellipsoidal models for regulatory purposes.
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Affiliation(s)
- E A Caffrey
- Oregon State University, Department of Nuclear Engineering and Radiation Health Physics, Corvallis, OR 97333, USA.
| | - M P Johansen
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
| | - K A Higley
- Oregon State University, Department of Nuclear Engineering and Radiation Health Physics, Corvallis, OR 97333, USA
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Caffrey EA, Johansen MP, Higley KA. Organ Dose-Rate Calculations for Small Mammals at Maralinga, the Nevada Test Site, Hanford and Fukushima: A Comparison of Ellipsoidal and Voxelized Dosimetric Methodologies. Radiat Res 2015; 184:433-41. [PMID: 26414505 DOI: 10.1667/rr14162.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Radiological dosimetry for nonhuman biota typically relies on calculations that utilize the Monte Carlo simulations of simple, ellipsoidal geometries with internal radioactivity distributed homogeneously throughout. In this manner it is quick and easy to estimate whole-body dose rates to biota. Voxel models are detailed anatomical phantoms that were first used for calculating radiation dose to humans, which are now being extended to nonhuman biota dose calculations. However, if simple ellipsoidal models provide conservative dose-rate estimates, then the additional labor involved in creating voxel models may be unnecessary for most scenarios. Here we show that the ellipsoidal method provides conservative estimates of organ dose rates to small mammals. Organ dose rates were calculated for environmental source terms from Maralinga, the Nevada Test Site, Hanford and Fukushima using both the ellipsoidal and voxel techniques, and in all cases the ellipsoidal method yielded more conservative dose rates by factors of 1.2-1.4 for photons and 5.3 for beta particles. Dose rates for alpha-emitting radionuclides are identical for each method as full energy absorption in source tissue is assumed. The voxel procedure includes contributions to dose from organ-to-organ irradiation (shown here to comprise 2-50% of total dose from photons and 0-93% of total dose from beta particles) that is not specifically quantified in the ellipsoidal approach. Overall, the voxel models provide robust dosimetry for the nonhuman mammals considered in this study, and though the level of detail is likely extraneous to demonstrating regulatory compliance today, voxel models may nevertheless be advantageous in resolving ongoing questions regarding the effects of ionizing radiation on wildlife.
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Affiliation(s)
- Emily A Caffrey
- a Oregon State University School of Nuclear Science and Engineering, Corvallis, Oregon; and
| | - Mathew P Johansen
- b Australian Nuclear Science and Technology Organisation, Kirrawee, Australia
| | - Kathryn A Higley
- a Oregon State University School of Nuclear Science and Engineering, Corvallis, Oregon; and
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