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Li S, Ni Y, Guo Q. Plutonium in the coastal seawater around Chinese nuclear power plants: Sources, distribution, and environmental implications. MARINE POLLUTION BULLETIN 2024; 207:116882. [PMID: 39178520 DOI: 10.1016/j.marpolbul.2024.116882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 08/18/2024] [Accepted: 08/18/2024] [Indexed: 08/26/2024]
Abstract
Coastal surface seawater samples within 30 km around ten Chinese nuclear power plants (NPPs) were systematically investigated. The 239+240Pu activity concentration in the samples varied from 0.226 mBq/m3 to 3.098 mBq/m3, meanwhile the 240Pu/239Pu atom ratios ranged from 0.151 to 0.353. Besides, the Pacific Proving Ground (PPG) close-in fallout and the global fallout were recognized as two primary sources of Pu in these samples. The 239+240Pu activity concentration as well as the PPG contribution showed similar trends as the Kuroshio intrusion path and the coastal currents in the China Seas, illustrating long-range transport and consuming of PPG derived Pu in the coastal China Seas. Moreover, accumulation of PPG sourced Pu in the Beibu Gulf were observed and was attributed to the continuous invasion of the high isotopic Pu that remobilized from the South China Sea (SCS).
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Affiliation(s)
- Sixuan Li
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China
| | - Youyi Ni
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China.
| | - Qiuju Guo
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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2
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Balboni E, Merino N, Begg JD, Samperton KM, Zengotita FE, Law GTW, Kersting AB, Zavarin M. Plutonium mobilization from contaminated estuarine sediments, Esk Estuary (UK). CHEMOSPHERE 2022; 308:136240. [PMID: 36057346 DOI: 10.1016/j.chemosphere.2022.136240] [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: 07/01/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Since 1952, liquid radioactive effluent containing238-242Pu, 241Am, 237Np, 137Cs, and 99Tc has been released with authorization from the Sellafield nuclear complex (UK) into the Irish Sea. This represents the largest source of plutonium (Pu) discharged in all western Europe, with 276 kg having been released. In the Eastern Irish Sea, the majority of the transuranic activity has settled into an area of sediments (Mudpatch) located off the Cumbrian coast. Radionuclides from the Mudpatch have been re-dispersed via particulate transport in fine-grained estuarine and intertidal sediments to the North-East Irish Sea, including the intertidal saltmarsh located at the mouth of the Esk Estuary. Saltmarshes are highly dynamic systems which are vulnerable to external agents (sea level change, erosion, sediment supply, and freshwater inputs), and their stability remains uncertain under current sea level rise projections and possible increases in storm activity. In this work, we examined factors affecting Pu mobility in contaminated sediments collected from the Esk Estuary by conducting leaching experiments under both anoxic and oxic conditions. Leaching experiments were conducted over a 9-month period and were periodically sampled to determine solution phase Pu via multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS), and to measure redox indicators (Eh, pH and extractable Fe(II)). Microbial community composition was also characterized in the sediments, and at the beginning and end of the anoxic/oxic experiments. Results show that: 1) Pu leaching is about three times greater in solutions leached under anoxic conditions compared to oxic conditions, 2) the sediment slurry microbial communities shift as conditions change from anoxic to oxic, 3) Pu leaching is enhanced in the shallow sediments (0-10 cm depth), and 4) the magnitude of Pu leached from sediments is not correlated with total Pu, indicating that the biogeochemistry of sediment-associated Pu is spatially heterogeneous. These findings provide constraints on the stability of redox sensitive Pu in biogeochemically dynamic/transient environments on a timescale of months and suggests that anoxic conditions can enhance Pu mobility in estuarine systems.
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Affiliation(s)
- Enrica Balboni
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States.
| | - Nancy Merino
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States
| | - James D Begg
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States; Amphos 21, Barcelona, Spain
| | - Kyle M Samperton
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States; Trace Nuclear Measurement Technology Group, Savannah River National Laboratory, Aiken, SC, 29808, United States
| | - Frances E Zengotita
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States; Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, IN, 46556, United States
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Finland
| | - Annie B Kersting
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States
| | - Mavrik Zavarin
- Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States
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3
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Chaplin JD, Christl M, Cundy AB, Warwick PE, Gaca P, Bochud F, Froidevaux P. Time-Integrated Bioavailability Proxy for Actinides in a Contaminated Estuary. ACS ES&T WATER 2022; 2:1688-1696. [PMID: 36277120 PMCID: PMC9578035 DOI: 10.1021/acsestwater.2c00194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/05/2022] [Accepted: 08/05/2022] [Indexed: 06/16/2023]
Abstract
Actinides accumulate within aquatic biota in concentrations several orders of magnitude higher than in the seawater [the concentration factor (CF)], presenting an elevated radiological and biotoxicological risk to human consumers. CFs currently vary widely for the same radionuclide and species, which limits the accuracy of the modeled radiation dose to the public through seafood consumption. We propose that CFs will show less dispersion if calculated using a time-integrated measure of the labile (bioavailable) fraction instead of a specific spot sample of bulk water. Herein, we assess recently developed configurations of the diffusive gradients in thin films (DGT) sampling technique to provide a more accurate predictor for the bioaccumulation of uranium, plutonium, and americium within the biota of the Sellafield-impacted Esk Estuary (UK). We complement DGT data with the cross-flow ultrafiltration of bulk seawater to assess the DGT-labile fraction versus the bulk concentration. Sequential elution of Fucus vesiculosis reveals preferential internalization and strong intracellular binding of less particle-reactive uranium. We find significant variations between CF values in biota calculated using a spot sample versus using DGT, which suggest an underestimation of the CF by spot sampling in some cases. We therefore recommend a revision of CF values using time-integrated bioavailability proxies.
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Affiliation(s)
- Joshua D. Chaplin
- Institute
of Radiation Physics, Lausanne University
Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland
| | - Marcus Christl
- Laboratory
of Ion Beam Physics, ETH Zürich, Otto-Stern-Weg 5, Zürich 8093, Switzerland
| | - Andrew B. Cundy
- School
of Ocean and Earth Science, University of
Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, U.K.
| | - Phillip E. Warwick
- School
of Ocean and Earth Science, University of
Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, U.K.
| | - Paweł Gaca
- School
of Ocean and Earth Science, University of
Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, U.K.
| | - François Bochud
- Institute
of Radiation Physics, Lausanne University
Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland
| | - Pascal Froidevaux
- Institute
of Radiation Physics, Lausanne University
Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland
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4
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Chaplin JD, Christl M, Cundy AB, Warwick PE, Reading DG, Bochud F, Froidevaux P. Bioavailable actinide fluxes to the Irish Sea from Sellafield-labelled sediments. WATER RESEARCH 2022; 221:118838. [PMID: 35841796 DOI: 10.1016/j.watres.2022.118838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/22/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Nuclear discharges to the oceans have given rise to significant accumulations of radionuclides in sediments which can later remobilise back into the water column. A continuing supply of radionuclides to aquatic organisms and the human food chain can therefore exist, despite the absence of ongoing nuclear discharges. Radionuclide remobilisation from sediment is consequently a critical component of the modelled radiation dose to the public. However, radionuclide remobilisation fluxes from contaminated marine sediments have never been quantitatively determined in-situ to provide a valid assessment of the issue. Here, we combine recent advances in the Diffusive Gradients in Thin Films (DGT) sampling technique with ultrasensitive measurement by accelerator mass spectrometry (AMS) to calculate the remobilisation fluxes of plutonium, americium and uranium isotopes from the Esk Estuary sediments (UK), which have accumulated historic discharges from the Sellafield nuclear reprocessing facility. Isotopic evidence indicates the local biota are accumulating remobilised plutonium and demonstrates the DGT technique as a valid bioavailability proxy, which more accurately reflects the elemental fractionation of the actinides in the biota than traditional bulk water sampling. These results provide a fundamental evaluation of the re-incorporation of bioavailable actinides into the biosphere from sediment reservoirs. We therefore anticipate this work will provide a tool and point of reference to improve radiation dose modelling and contribute insight for other environmental projects, such as the near-surface and deep disposal of nuclear waste.
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Affiliation(s)
- Joshua D Chaplin
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland.
| | - Marcus Christl
- Laboratory of Ion Beam Physics, ETH Zürich, Otto-Stern-Weg, Zürich 8093, Switzerland
| | - Andrew B Cundy
- School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK
| | - Phillip E Warwick
- School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK
| | - David G Reading
- School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, UK
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland
| | - Pascal Froidevaux
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, Lausanne 1007, Switzerland.
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5
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Chaplin JD, Warwick PE, Cundy AB, Bochud F, Froidevaux P. Novel DGT Configurations for the Assessment of Bioavailable Plutonium, Americium, and Uranium in Marine and Freshwater Environments. Anal Chem 2021; 93:11937-11945. [PMID: 34432435 DOI: 10.1021/acs.analchem.1c01342] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plutonium, americium, and uranium contribute to the radioactive contamination of the environment and are risk factors for elevated radiation exposure via ingestion through food or water. Due to the significant environmental inventory of these radioelements, a sampling method to accurately monitor their bioavailable concentrations in natural waters is necessary, especially since physicochemical factors can cause significant temporal fluctuations in their waterborne concentrations. To this end, we engineered novel diffusive gradients in thin-film (DGT) configurations using resin gels, which are selective for UO22+, Pu(IV + V), and Am(III) among an excess of extraneous cations. In this work, we also report an improved synthesis of our in-house ion-imprinted polymer resin, which we used to manufacture a resin gel to capture Am(III). The effective diffusion coefficients of Pu, Am, and U in agarose cross-linked polyacrylamide were determined in freshwater and seawater simulants and in natural seawater, to calibrate these configurations for environmental deployments.
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Affiliation(s)
- Joshua D Chaplin
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, CH-1007 Lausanne, Switzerland
| | - Phillip E Warwick
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom
| | - Andrew B Cundy
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, CH-1007 Lausanne, Switzerland
| | - Pascal Froidevaux
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, 1 Rue du Grand-Pré, CH-1007 Lausanne, Switzerland
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6
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Rozhkova AK, Kuzmenkova NV, Pryakhin EA, Mokrov YG, Kalmykov SN. Artificial radionuclides association with bottom sediment components from Mayak Production Association industrial reservoirs. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 232:106569. [PMID: 33714079 DOI: 10.1016/j.jenvrad.2021.106569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 02/09/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
About ten years have passed since the last published report in Russian on the speciation and distribution features of radionuclides in the bottom sediment of Production Association (PA) "Mayak" (further mentioned as Mayak) artificial reservoirs. Herein, the desorption parameters of 137Cs, 90Sr, 241Am, and 238,239+240Pu and their association with bottom sediment components were investigated in two Mayak reservoirs (R-17 (decommissioned) and R-4 (still in use) with big differences in size, activity and water regime). It was established that 137Cs and 90Sr desorption from the R-17 bottom sediment reach constant values after 24 h, and the desorption degree is not dependant on pH but on ionic strength. Sequential extraction indicated that the main accumulation mechanism of 137Cs is incorporation into the clay minerals. The maximum plutonium content was detected in the residual fraction of the R-17 bottom sediment, which could be associated with the effects of precipitation aging. In R-4, plutonium is equally distributed between residual and bound to organic matter fractions. The 241Am is associated with carbonates in the R-17 bottom sediment and with organic matter in the R-4 bottom sediment and to lesser extent with iron-manganese oxides. The radionuclides are becoming less environmentally available with time since deposition.
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Affiliation(s)
- A K Rozhkova
- Chemistry Department, Radiochemistry Division, Lomonosov MSU, 119991, Moscow, Russia; Vernadsky Institute of Geochemistry and Analytical Chemistry of RAS, 119334, Moscow, Russia.
| | - N V Kuzmenkova
- Chemistry Department, Radiochemistry Division, Lomonosov MSU, 119991, Moscow, Russia; Vernadsky Institute of Geochemistry and Analytical Chemistry of RAS, 119334, Moscow, Russia
| | - E A Pryakhin
- Urals Research Center for Radiation Medicine, 454076, Chelyabinsk, Russia
| | - Y G Mokrov
- Mayak Production Association, 456780, Ozersk, Russia
| | - S N Kalmykov
- Chemistry Department, Radiochemistry Division, Lomonosov MSU, 119991, Moscow, Russia; Vernadsky Institute of Geochemistry and Analytical Chemistry of RAS, 119334, Moscow, Russia
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7
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Ray D, Leary P, Livens F, Gray N, Morris K, Law KA, Fuller AJ, Abrahamsen-Mills L, Howe J, Tierney K, Muir G, Law GTW. Controls on anthropogenic radionuclide distribution in the Sellafield-impacted Eastern Irish Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140765. [PMID: 32659564 DOI: 10.1016/j.scitotenv.2020.140765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Understanding anthropogenic radionuclide biogeochemistry and mobility in natural systems is key to improving the management of radioactively contaminated environments and radioactive wastes. Here, we describe the contemporary depth distribution and phase partitioning of 137Cs, Pu, and 241Am in two sediment cores taken from the Irish Sea (Site 1: the Irish Sea Mudpatch; Site 2: the Esk Estuary). Both sites are located ~10 km from the Sellafield nuclear site. Low-level aqueous radioactive waste has been discharged from the Sellafield site into the Irish Sea for >50 y. We compare the depth distribution of the radionuclides at each site to trends in sediment and porewater redox chemistry, using trace element abundance, microbial ecology, and sequential extractions, to better understand the relative importance of sediment biogeochemistry vs. physical controls on radionuclide distribution/post-depositional mobility in the sediments. We highlight that the distribution of 137Cs, Pu, and 241Am at both sites is largely controlled by physical mixing of the sediments, physical transport processes, and sediment accumulation. Interestingly, at the Esk Estuary, microbially-mediated redox processes (considered for Pu) do not appear to offer significant controls on Pu distribution, even over decadal timescales. We also highlight that the Irish Sea Mudpatch likely still acts as a source of historical pollution to other areas in the Irish Sea, despite ever decreasing levels of waste output from the Sellafield site.
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Affiliation(s)
- Daisy Ray
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Peter Leary
- School of Natural and Environmental Sciences, Newcastle University, Newcastle NE1 7RU, UK
| | - Francis Livens
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK; Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Neil Gray
- School of Natural and Environmental Sciences, Newcastle University, Newcastle NE1 7RU, UK
| | - Katherine Morris
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Kathleen A Law
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki 00014, Finland
| | - Adam J Fuller
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK
| | | | - John Howe
- Scottish Association for Marine Science, Scottish Marine Institute, Dunbeg-by-Oban PA37 1QA, UK
| | - Kieran Tierney
- Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, Rankine Avenue, Glasgow G75 0QF, UK
| | - Graham Muir
- Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, Rankine Avenue, Glasgow G75 0QF, UK
| | - Gareth T W Law
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, Helsinki 00014, Finland.
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8
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Rozhkova AK, Kuzmenkova NV, Kangina OA, Pryakhin EA, Mokrov YG, Kalmykov SN. Radionuclide Sequential Extraction from Reservoir R-17 Bottom Sediments of the Mayak Production Association. RADIOCHEMISTRY 2019. [DOI: 10.1134/s1066362219060213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Faye SA, Richards JM, Gallardo AM, Campbell KR, Sudowe R. Development of a standardized sequential extraction protocol for simultaneous extraction of multiple actinide elements. J Radioanal Nucl Chem 2017. [DOI: 10.1007/s10967-017-5188-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Caborn JA, Howard BJ, Blowers P, Wright SM. Spatial trends on an ungrazed West Cumbrian saltmarsh of surface contamination by selected radionuclides over a 25 year period. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 151 Pt 1:94-104. [PMID: 26440699 DOI: 10.1016/j.jenvrad.2015.09.011] [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: 12/12/2014] [Revised: 09/07/2015] [Accepted: 09/09/2015] [Indexed: 06/05/2023]
Abstract
Long term spatial and temporal variations in radionuclide activity have been measured in a contaminated ungrazed saltmarsh near Ravenglass, Cumbria. Over a twenty-five year period there has been a decrease in activity concentration with (106)Ru and (137)Cs showing the highest rate of change followed by Pu alpha and (241)Am. A number of factors contribute to the reduction with time; including radiological half lives, discharge and remobilisation. For (241)Am the lower reduction rate is partially due to ingrowth from (241)Pu and partially as a result of transport of sediment from the offshore Irish Sea mud patch. Considerable spatial variation for the different radionuclides was observed, which with time became less defined. The highest activity concentrations of long-lived radionuclides were in low energy areas, typically where higher rates of sedimentation and vegetation occurred. The trend was reversed for the shorter lived radionuclide, (106)Ru, with higher activity concentrations observed in high energy areas where there was frequent tidal inundation. Surface scrape samples provide a pragmatic, practical method of measuring sediment contamination over large areas and is a sampling approach adopted by most routine environmental monitoring programs, but it does not allow for interpretation of the effect of variation in sedimentation rates. This paper proposes a method for calculating indicative sedimentation rates across the saltmarsh using surface scrape data, which produces results consistent with values experimentally obtained.
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Affiliation(s)
- Jane A Caborn
- Centre for Ecology & Hydrology - Lancaster, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK; NNL, Preston Laboratory, A709, Springfields, Salwick, Preston, PR4 0XJ, UK.
| | - Brenda J Howard
- Centre for Ecology & Hydrology - Lancaster, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK
| | - Paul Blowers
- Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, UK
| | - Simon M Wright
- Centre for Ecology & Hydrology - Lancaster, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK
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11
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Bu W, Fukuda M, Zheng J, Aono T, Ishimaru T, Kanda J, Yang G, Tagami K, Uchida S, Guo Q, Yamada M. Release of Pu isotopes from the Fukushima Daiichi Nuclear Power Plant accident to the marine environment was negligible. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9070-9078. [PMID: 25050458 DOI: 10.1021/es502480y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Atmospheric deposition of Pu isotopes from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has been observed in the terrestrial environment around the FDNPP site; however, their deposition in the marine environment has not been studied. The possible contamination of Pu in the marine environment has attracted great scientific and public concern. To fully understand this possible contamination of Pu isotopes from the FDNPP accident to the marine environment, we collected marine sediment core samples within the 30 km zone around the FDNPP site in the western North Pacific about two years after the accident. Pu isotopes ((239)Pu, (240)Pu, and (241)Pu) and radiocesium isotopes ((134)Cs and (137)Cs) in the samples were determined. The high activities of radiocesium and the (134)Cs/(137)Cs activity ratios with values around 1 (decay corrected to 15 March 2011) suggested that these samples were contaminated by the FDNPP accident-released radionuclides. However, the activities of (239+240)Pu and (241)Pu were low compared with the background level before the FDNPP accident. The Pu atom ratios ((240)Pu/(239)Pu and (241)Pu/(239)Pu) suggested that global fallout and the pacific proving ground (PPG) close-in fallout are the main sources for Pu contamination in the marine sediments. As Pu isotopes are particle-reactive and they can be easily incorporated with the marine sediments, we concluded that the release of Pu isotopes from the FDNPP accident to the marine environment was negligible.
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Affiliation(s)
- Wenting Bu
- Research Center of Radiation Protection, National Institute of Radiological Sciences , Anagawa 4-9-1, Inage, Chiba 263-8555, Japan
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12
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Gleizon P, McDonald P. Modelling radioactivity in the Irish Sea: from discharge to dose. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:403-413. [PMID: 20346549 DOI: 10.1016/j.jenvrad.2010.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 01/20/2010] [Accepted: 02/25/2010] [Indexed: 05/29/2023]
Abstract
In order to support authorised discharges of low level radioactive liquid effluent into coastal regions, mathematical models are required to robustly predict radiological impacts on critical groups of current and proposed changes to liquid discharges. The grid model presented here simulates the long term dispersion and transport of radioactivity discharged from the Sellafield site in Cumbria, UK, and the subsequent exposure of critical groups in Cumbria and across the Irish Sea in Northern Ireland. The fine grid of the model allows a good resolution of the seabed sediment distribution. This benefits the predictions for the last decades of low discharge level, when bed sediment can become a source of contamination by bringing back the legacy of past high discharges. This is highlighted by the dose comparison, where the predicted dose to Cumbria critical group follows well the dose estimated from environmental data during the low discharge level period.
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Affiliation(s)
- P Gleizon
- Westlakes Scientific Consulting Ltd., Westlakes Science & Technology Park, Moor Row, Cumbria, UK.
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13
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Qiao J, Hou X. Fractionation of plutonium in environmental and bio-shielding concrete samples using dynamic sequential extraction. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:244-9. [PMID: 20004047 DOI: 10.1016/j.jenvrad.2009.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 11/23/2009] [Accepted: 11/25/2009] [Indexed: 05/10/2023]
Abstract
Fractionation of plutonium isotopes ((238)Pu, (239,240)Pu) in environmental samples (i.e. soil and sediment) and bio-shielding concrete from decommissioning of nuclear reactor were carried out by dynamic sequential extraction using an on-line sequential injection (SI) system combined with a specially designed extraction column. Plutonium in the fractions from the sequential extraction was separated by ion exchange chromatography and measured using alpha spectrometry. The analytical results show a higher mobility of plutonium in bio-shielding concrete, which means attention should be paid to the treatment and disposal of nuclear waste from decommissioning.
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Affiliation(s)
- Jixin Qiao
- Radiation Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark
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14
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Lindahl P, Lee SH, Worsfold P, Keith-Roach M. Plutonium isotopes as tracers for ocean processes: a review. MARINE ENVIRONMENTAL RESEARCH 2010; 69:73-84. [PMID: 19773079 DOI: 10.1016/j.marenvres.2009.08.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 05/28/2023]
Abstract
Since the first nuclear weapons tests in the 1940s, pulsed inputs of plutonium isotopes have served as excellent tracers for understanding sources, pathways, dynamics and the fate of pollutants and particles in the marine environment. Due to the well-defined spatial and temporal inputs of Pu, the long half-lives of (240)Pu and (239)Pu and its unique chemical properties, Pu is a potential tracer for various physical and biogeochemical ocean processes, including circulation, sedimentation and biological productivity, and hence a means of assessing the impacts of global climate change. Due to the source dependency of the Pu isotopic signature, plutonium isotopes are beginning to be exploited as tools for the evaluation and improvement of regional and global ocean models that will enhance understanding of past and future changes in the oceans. This paper addresses the major sources of Pu and the physical and biogeochemical behaviour in the marine environment. Finally, the use of Pu isotopes as tracers for various oceanic processes (e.g. water mass transport, particle export, and sedimentation) is considered.
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Affiliation(s)
- Patric Lindahl
- Marine Environment Research Department, Korea Ocean Research and Development Institute, Ansan, P.O. Box 29, Seoul 425-600, Republic of Korea.
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15
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Wilson RC, Watts SJ, Vives i Batlle J, McDonald P. Laboratory and field studies of polonium and plutonium in marine plankton. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2009; 100:665-669. [PMID: 19552987 DOI: 10.1016/j.jenvrad.2009.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 04/16/2009] [Accepted: 05/22/2009] [Indexed: 05/28/2023]
Abstract
Uptake experiments were successfully undertaken for polonium and plutonium in the marine diatom Skeletonema costatum. Experiments were complemented with a field study which yielded concentration factors for these radionuclides for plankton samples collected in the eastern Irish Sea. The uptake experiment produced uptake half times of 0.8 and 0.6 days for plutonium and polonium, respectively. Concentration factors of 3.1 x 10(5) l kg(-1) for plutonium and 2.4 x 10(5) l kg(-1) for polonium were consistent with those suggested by the IAEA for phytoplankton. Concentration factors derived from the field study were 2 x 10(3) l kg(-1) for plutonium and 1.4 x 10(4) l kg(-1) for polonium and were more consistent with IAEA values for zooplankton rather than phytoplankton. The maximum calculated dose rate due to Po and Pu in plankton sampled in the field was 0.12 microGyh(-1). In applying the laboratory-derived phytoplankton CF values for Po and Pu, higher dose rates, in the range 6-11 microGyh(-1), were calculated. The latter values are well below the UNSCEAR and IAEA review value of 400 microGyh(-1), and are also below the Environment Agency marine action level of 40 microGyh(-1).
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Affiliation(s)
- R C Wilson
- Westlakes Scientific Consulting Ltd., The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3LN, UK.
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Vives I Batlle J, Wilson RC, Watts SJ, Jones SR, McDonald P, Vives-Lynch S. Dynamic model for the assessment of radiological exposure to marine biota. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:1711-1730. [PMID: 18164107 DOI: 10.1016/j.jenvrad.2007.11.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 10/12/2007] [Accepted: 11/09/2007] [Indexed: 05/25/2023]
Abstract
A generic approach has been developed to simulate dynamically the uptake and turnover of radionuclides by marine biota. The approach incorporates a three-compartment biokinetic model based on first order linear kinetics, with interchange rates between the organism and its surrounding environment. Model rate constants are deduced as a function of known parameters: biological half-lives of elimination, concentration factors and a sample point of the retention curve, allowing for the representation of multi-component release. The new methodology has been tested and validated in respect of non-dynamic assessment models developed for regulatory purposes. The approach has also been successfully tested against research dynamic models developed to represent the uptake of technetium and radioiodine by lobsters and winkles. Assessments conducted on two realistic test scenarios demonstrated the importance of simulating time-dependency for ecosystems in which environmental levels of radionuclides are not in equilibrium.
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Affiliation(s)
- J Vives I Batlle
- Westlakes Scientific Consulting Ltd, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3LN, UK.
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Petersen R, Hou X, Hansen EH. Evaluation of the readsorption of plutonium and americium in dynamic fractionations of environmental solid samples. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:1165-1174. [PMID: 18359133 DOI: 10.1016/j.jenvrad.2008.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 12/05/2007] [Accepted: 01/30/2008] [Indexed: 05/26/2023]
Abstract
A dynamic extraction system exploiting sequential injection (SI) for sequential extractions incorporating a specially designed extraction column is developed to fractionate radionuclides in environmental solid samples such as soils and sediments. The extraction column can contain up to 5 g of a soil sample, and under optimal operational conditions it does not give rise to creation of back pressure. Attention has been placed on studies of the readsorption problems during sequential extraction using a modified Standards, Measurements and Testing (SM&T) scheme with four-step sequential extractions. The degree of readsorption in dynamic and conventional batch extraction systems is compared and evaluated by using a double-spiking technique. A high degree of readsorption of plutonium and americium (>75%) was observed in both systems, and they also exhibited similar distribution patterns of the two radionuclides. However, the dynamic system is fully automated, eliminates manual separations, significantly reduces the operational time required, and offers detailed kinetic information.
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Affiliation(s)
- Roongrat Petersen
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Building 207, 2800 Kgs Lyngby, Denmark.
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Vives I Batlle J, Bryan S, McDonald P. A process-based model for the partitioning of soluble, suspended particulate and bed sediment fractions of plutonium and caesium in the eastern Irish Sea. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2008; 99:62-80. [PMID: 17719705 DOI: 10.1016/j.jenvrad.2007.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 06/21/2007] [Accepted: 06/27/2007] [Indexed: 05/16/2023]
Abstract
A dynamic model of plutonium behaviour in the marine environment has been developed, representing the oxidation state distribution and partitioning of plutonium between the soluble, colloidal, suspended particulate and seabed sediment fractions. With simple re-parameterisation, this model can also be applied to (137)Cs. The model, which is calibrated and validated against field data, has been used to predict concentrations of Pu(alpha) and (137)Cs in both water and seabed sediments from the vicinity of the Sellafield Ltd. reprocessing plant in Cumbria, UK. The model predicts that sediment reworking and transport are the key environmental processes as the Sellafield Pu(alpha) and (137)Cs discharge continues to decline. Inventory calculations generated by the model are consistent with previous estimations. For a hypothetical post-discharge scenario, the concentrations of these radionuclides in both seawater and surface sediments are predicted to decrease sharply, concurrent with a downward vertical migration of the activity retained in sediments.
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Affiliation(s)
- J Vives I Batlle
- Westlakes Scientific Consulting Ltd, The Princess Royal Building, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3LN, UK.
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19
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Abstract
Since their introduction in the late 1970s, sequential extraction procedures have experienced a rapid increase in use. They are now applied for a large number of potentially toxic elements in a wide range of sample types. This review uses evidence from the literature to consider the usefulness and limitations of sequential extraction and thereby to assess its future role in environmental chemical analysis. It is not the intention to provide a comprehensive survey of all applications of sequential extractions or to consider the merits and disadvantages of individual schemes. These aspects have been covered adequately in other, recent reviews. This review focuses in particular on various key issues surrounding sequential extractions such as nomenclature, methodologies, presentation of data and interpretation of data, and discusses typical applications from the recent literature for which sequential extraction can provide useful and meaningful information. Also covered are emerging developments such as accelerated procedures using ultrasound- or microwave energy-assisted extractions, dynamic extractions, the use of chemometrics, the combination of sequential extraction with isotope analysis, and the extension of the approach to non-traditional analytes such as arsenic, mercury, selenium and radionuclides.
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Affiliation(s)
- Jeffrey R Bacon
- The Macaulay Institute, Craigiebuckler, Aberdeen, UKAB15 8QH
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Lucey JA, Vintró LL, Boust D, Mitchell PI, Gouzy A, Bowden L. A novel approach to the sequential extraction of plutonium from oxic and anoxic sediment using sodium citrate to inhibit post-extraction resorption. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2007; 93:63-73. [PMID: 17241715 DOI: 10.1016/j.jenvrad.2006.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 11/20/2006] [Indexed: 05/13/2023]
Abstract
Sequential extraction has been used extensively to study the solid partitioning of radionuclides in soils and sediments. A difficulty with sequential extraction is that radionuclides released by a particular extractant can be resorbed and artificially redistributed amongst the remaining solid phases. Here, we describe experiments (on selected model phase and natural materials), which were designed to determine whether the inclusion of a chelating agent (sodium citrate) in an established sequential extraction protocol (a) inhibits post-extraction resorption of plutonium, (b) increases non-targeted dissolution of sediment phases, and (c) gives rise to unwanted ligand competition for plutonium. The results clearly demonstrate the capacity of citrate to inhibit the resorption of plutonium from the various extractants, and confirm that there is no discernible increase in non-targeted phase dissolution, but indicate significant ligand competition with the carbonate phase. The merits of using citrate are discussed and an optimised sequential extraction protocol that includes citrate is proposed. Finally, the protocol is applied to oxic and anoxic sediments sampled in the NE Irish Sea and the Roads of Cherbourg, and it is shown that the bulk of the plutonium on these sediments is associated with the more labile geochemical fractions.
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Affiliation(s)
- Julie A Lucey
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
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Charlesworth ME, Service M, Gibson CE. The distribution and transport of Sellafield derived 137 Cs and 241 Am to western Irish Sea sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2006; 354:83-92. [PMID: 16376698 DOI: 10.1016/j.scitotenv.2004.12.062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Accepted: 12/23/2004] [Indexed: 05/05/2023]
Abstract
Sellafield derived (137)Cs and (241)Am were analysed in surficial sediments at 23 sites in the western Irish Sea. Concentrations varied between 3-175 Bq (137)Cs/kg and 1-147 Bq (241)Am/kg. There are two distinct basins in the western Irish Sea separated by an area of restricted depth and this bathymetry is reflected in the radionuclide concentrations. Highest concentrations were found in the northerly samples and substantially lower concentrations further south. This pattern of distribution can be explained by the predominantly northerly residual flow and the existence of seasonal stratification in this area of weak tides. (137)Cs/(241)Am ratios were also highest in the northern basin, and it is suggested that this is caused by differences in the mechanisms of transport of the two elements. The direct physical migration of contaminated particles from the eastern Irish Sea is the dominant transport mechanism in the north of the study area, whereas transport in the dissolved phase is most important to the southern region. Concentrations of both elements were best correlated with the percentage <15 microm particulate fraction suggesting that particles within this range are most important for direct transport and scavenging from the soluble phase.
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Affiliation(s)
- M E Charlesworth
- Department of Agriculture and Environmental Science, The Queens University of Belfast, Newforge Lane, Belfast BT9 5PX, Northern Ireland.
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McCubbin D, Leonard KS, Greenwood RC, Taylor BR. Solid-solution partitioning of plutonium in surface waters at the Atomic Weapons Establishment Aldermaston (UK). THE SCIENCE OF THE TOTAL ENVIRONMENT 2004; 332:203-216. [PMID: 15336903 DOI: 10.1016/j.scitotenv.2004.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Revised: 04/19/2004] [Accepted: 04/26/2004] [Indexed: 05/24/2023]
Abstract
The Atomic Weapons Establishment (AWE) at Aldermaston (Berkshire, UK) has provided and maintained the warheads for the UK's nuclear deterrent for more than 50 years. Whilst the site is radiologically safe, in a few locations the soil contains specific activities of plutonium (Pu) above background arising from a legacy of historic operations. Run-off water (a mixture of rainwater and groundwater) from part of the site is routed into a water management system, and after analysis and radiological assessment, released into local streams. Water and sediment samples have been collected from a number of closely spaced locations within this system to assess the solid-solution partitioning of Pu. Survey work was complemented by batch type desorption experiments to assess redissolution from 'contaminated' sediment into 'uncontaminated' water. The survey data indicate that specific activities of both dissolved and particle bound 239 + 240Pu varied by roughly two orders of magnitude, ranging from approximately 0.7 microBq kg(-1) up to approximately 44 microBq kg(-1), and approximately 1.2 Bq kg(-1) up to approximately 400 Bq kg(-1), respectively, consistent with water originating from different parts of the site. Apparent Kd values varied by an order of magnitude (from 0.7-16 x 10(6)) with an average value of 4 x 10(6). Results from the desorption experiments indicated the extent of redissolution was very small and the derived Kd's corroborated values obtained from the survey work. Kd's given here are compared with other literature values, and are the greatest reported to date. Results are also provided describing the variation in water quality parameters in shallow groundwater samples. Alkalinity values ranged from 120 to 388 mg l(-1) CaCO3 with an average value of 195 mg l(-1) CaCO3. Corresponding values for pH were 6.6-8.3 with an average of 7.5. Over half of the samples were estimated to be supersaturated with respect to calcite. It is suggested that the state of calcite saturation may be responsible for the high Pu Kd. As a consequence of the high particle reactivity, migration of Pu contamination, both within and away from the AWE Aldermaston site, is likely to be very restricted.
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Affiliation(s)
- David McCubbin
- CEFAS Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 OHT, UK.
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Mukerjee S, Norris GA, Smith LA, Noble CA, Neas LM, Ozkaynak AH, Gonzales M. Receptor model comparisons and wind direction analyses of volatile organic compounds and submicrometer particles in an arid, binational, urban air shed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:2317-2327. [PMID: 15116836 DOI: 10.1021/es0304547] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The relationship between continuous measurements of volatile organic compounds sources and particle number was evaluated at a Photochemical Assessment Monitoring Station Network (PAMS) site located near the U.S.-Mexico Border in central El Paso, TX. Sources of volatile organic compounds (VOCs) were investigated using the multivariate receptor model UNMIX and the effective variance least squares receptor model known as Chemical Mass Balance (CMB, Version 8.0). As expected from PAMS measurements, overall findings from data screening as well as both receptor models confirmed that mobile sources were the major source of VOCs. Comparison of hourly source contribution estimates (SCEs) from the two receptor models revealed significant differences in motor vehicle exhaust and evaporative gasoline contributions. However, the motor vehicle exhaust contributions were highly correlated with each other. Motor vehicle exhaust was also correlated with the ultrafine and accumulation mode particle count, which suggests that motor vehicle exhaust is a source of these particles at the measurement site. Wind sector analyses were performed using the SCE and pollutant data to assess source location of VOCs, particle count, and criteria pollutants. Results from this study have application to source apportionment studies and mobile source emission control strategies that are ongoing in this air shed.
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Affiliation(s)
- Shaibal Mukerjee
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, MD E205-02, Research Triangle Park, North Carolina 27711, USA.
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McCubbin D, Leonard KS, Young AK, Maher BA, Bennett S. Application of a magnetic extraction technique to assess radionuclide-mineral association in Cumbrian shoreline sediments. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2004; 77:111-131. [PMID: 15312698 DOI: 10.1016/j.jenvrad.2004.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Revised: 02/09/2004] [Accepted: 02/20/2004] [Indexed: 05/24/2023]
Abstract
An assessment has been made of the association of (239+240)Pu, 241Am and 210Po (in secular equilibrium with 210Pb) with iron minerals using a magnetic extraction technique. Grab samples of beach sand from the Cumbrian (UK) coastline were subjected to successive extractions with an approximately 0.1 T ferrite magnet and an approximately 0.3 T rare-earth magnet procedure to separate magnetic iron oxide minerals. Radionuclide concentrations in the magnetic extracts were enhanced (by approximately 4-6-fold) relative to the residue. Those in the approximately 0.1 T magnet extracts were broadly similar to those in the antiferromagnetic material extracted by the approximately 0.3 T magnet, despite the very large differences in magnetic property values between the two fractions (one to two orders of magnitude). The percentage of magnetic material in terms of mass was small and therefore, the majority of these radionuclides (on average 88%) were associated with the residue. Removal of stable Fe was incomplete. Given that the radionuclides may also bind to paramagnetic (nonmagnetic) Fe minerals, the data were extrapolated by normalising the results to quantitative Fe removal. This yielded average values of 37%, 45% and 46% for (239+240)Pu, 241Am and 210Po(210Pb), respectively, as upper limits for the fraction associated with magnetic + nonmagnetic Fe minerals. There are significant uncertainties inherent in quantifying data from this extraction technique. Nevertheless, it seems reasonable to conclude that radionuclide association with Fe minerals is unlikely to have a significant impact upon the physical dispersion of sediment contaminated by Sellafield discharges in the Irish Sea. However, it may be an important factor in governing Pu redox and redissolution behaviour.
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Affiliation(s)
- David McCubbin
- Lowestoft Laboratory, The Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Pakefield Road, Lowestoft, Suffolk NR33 OHT, UK.
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Smith CN, Goshawk JA, Charles K, McDonald P, Leonard KS, McCubbin D. MEAD (part II)-Predictions of radioactivity concentrations in the Irish Sea. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2003; 68:193-214. [PMID: 12782473 DOI: 10.1016/s0265-931x(03)00041-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The predictions from MEAD, a model that simulates the transport of radionuclides in the marine environment, are presented for the Irish Sea. MEAD predictions for (137)Cs and Pu(alpha) are presented following discharges from BNFL Sellafield and the predictions compared to measured data from near the discharge location and further a field in the Irish Sea. The model performs well in most circumstances given the uncertainties involved in both modelling and data collection although some inconsistencies in the predictions are found. MEAD is also compared to other models of radionuclide transport in the Irish Sea.
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Affiliation(s)
- C N Smith
- Department of Environmental Science, Westlakes Scientific Consulting Ltd, Princess Royal Building, Westlakes Science and Technology Park, Cumbria, CA24 3LN, Moor Row, UK
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