Recent observations on the physico-chemical speciation of plutonium in the Irish Sea and the western Mediterranean

Mitchell, P.I.; Batlle, J. Vives i; Downes, A.B.; Condren, O.M.; Vintró, Luis León; Sánchez-Cabeza, Joan-Albert

doi:10.1016/0969-8043(95)00160-f

Cited by 78 publications

(47 citation statements)

References 21 publications

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“…Thus, looking for geochemical reasons to explain groundwater Pu speciation variability between the SRS study and K-27 is complicated by this 244 Cm source of oxidized 240 Pu at SRS F-Area. Furthermore, environmental and lab based data are not consistent as to the predicted oxidation states of Pu and the geochemical controls thereof (Baxter et al, 1995;Cleveland, 1979;Mitchell et al, 1995). While reduced and oxidized Pu may coexist in a same aquatic environment, Pu(IV) is usually a stable form which interacts with anionic species for complexation through ionic bonding (Choppin, 1988;Cleveland, 1979;Dozol and Hagemann, 1993).…”

Section: Redox Fractionation Resultsmentioning

confidence: 99%

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

Dai

Buesseler

Pike

2005

Journal of Contaminant Hydrology

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We examined the concentration, size distribution, redox state and isotopic composition of plutonium (Pu) in groundwater at the 100K-Area at the US Department of Energy's (DOE) Hanford Site. Total concentrations of Pu isotopes were extremely low (10 -4 to 10 -6 pCi/kg, ≈ 10 4 to 10 6 atoms/kg), but measurable for the first time in the 100K-Area wells using mass spectrometric analyses that are much more sensitive than alpha spectroscopy methods used previously. Size fractionation data from two wells suggests that 7-29% of the Pu is associated with colloids, operationally defined here as particles between 1 kDa -0.2 µm in size. These colloids were collected using a 1 kDa cross-flow ultrafiltration system developed specifically for groundwater actinide studies to include careful controls both in the field and during processing to ensure in-situ geochemical conditions are maintained and size separations can be well characterized. Pu in this colloidal fraction was exclusively in the more reduced Pu(III/IV) form, consistent with the higher affinity of Pu for particle surfaces in the lower oxidation states. While the overall concentrations of Pu were low, the Pu isotopic composition suggests at least two local sources of groundwater Pu, namely local Hanford reactor operations at the 100K-Area, and spent nuclear fuel from the N reactor, which was stored in concrete pools at this site.Differences between this site and the Savannah River Site (SRS) are noted, since groundwater Pu at the F-Area seepage basin at SRS has been found using these same 2 methods, to be characterized by much lower colloidal abundances and higher oxidation states. This difference is not directly attributable to groundwater redox potential or geochemical conditions, but rather the physical-chemical difference in Pu sources, which at SRS appear to be dominated downstream from the seepage basins by decay of 244 Cm, resulting in more oxidized forms of 240 Pu. There is no clear evidence for colloid facilitated transport of Pu in groundwater at this site, since downstream wells have both an order of magnitude lower concentrations of Pu, but also a lower fractional colloidal distribution.

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Section: Redox Fractionation Resultsmentioning

confidence: 99%

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

Dai

Buesseler

Pike

2005

Journal of Contaminant Hydrology

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“…The Pu(IV) form is highly particle reactive and easily scavenged by suspended matter and colloids, while Pu(V) is relatively soluble and can be transported in the dissolved phase over long distances. Field studies in the Irish Sea and the Mediterranean Sea have shown that Pu(V) is the prevailing species in the dissolved phase and that particulate Pu is almost entirely in the reduced Pu(IV) form (Mitchell et al, 1995). In anoxic seawater Pu(III) is the dominant oxidation state (Sanchez et al, 1994).…”

Section: Behaviour Of Pu In the Marine Environmentmentioning

confidence: 99%

“…Interaction with complexing agents and hydrolysis reactions are generally strongest for Pu(IV) and weakest for Pu(V), which leads to the preferential removal of reduced Pu species from solution by adsorption onto colloidal and suspended material (Nelson and Lovett, 1978;Orlandini et al, 1990;Mitchell et al, 1995). In contrast, oxidised Pu(V) has a high 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 13 affinity for adsorption onto carbonate particles, e.g.…”

Section: Behaviour Of Pu In the Marine Environmentmentioning

confidence: 99%

Plutonium isotopes as tracers for ocean processes: A review

Lindahl

Lee

Worsfold

et al. 2010

Marine Environmental Research

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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- 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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“…The precipitate was dissolved by warming with HNO 3 (5 ml, 8 M) and saturated H 3 BO 3 (2 ml), and the solution was then transferred to a polyethylene centrifuge tube (50 ml). The volume was made up to 40 ml with water and concentrated NH 4 OH was added until the solution pH was greater than 9. Thereupon, Nd(OH) 3 was precipitated.…”

Section: Removal Of Excess Fluoride and Nd(oh) 3 Precipitationmentioning

confidence: 99%

“…Dissolved 239 + 240 Pu can exist in at least two valence states in seawater. In the Irish Sea dissolved 239 + 240 Pu has been reported to be predominantly (70%-90%) in the V-valent state [3,4], whereas 239 + 240 Pu associated with particulate material exists almost entirely (Ͼ 98%) in the IV-valent state [5]. It has also been suggested that Pu(V) can bind to particulate material and that the uptake of Pu(V) species involves the reduction to Pu(IV) at the particle-solution interface [6].…”

Section: Introductionmentioning

confidence: 99%

Determination of plutonium in seawater using co-precipitation and inductively coupled plasma mass spectrometry with ultrasonic nebulisation

Eroğlu

McLeod

Leonard

et al. 1998

Spectrochimica Acta Part B: Atomic Spectroscopy

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A flow injection-inductively coupled plasma-mass spectrometric (FI-ICP-MS) procedure, utilising ultrasonic nebulisation with membrane desolvation (USN/MD), has been developed for the determination of plutonium (Pu) in seawater at fg l −1 concentration levels. Seawater samples (1 l), after filtration, were subjected to co-precipitation with NdF 3 , followed by ion exchange to enrich Pu and to reject seawater matrix ions and co-existing uranium. The seawater concentrate (1.0 ml) was then analysed by FI-ICP-MS. The limit of detection for 239 Pu in seawater based on an enrichment factor of 1000 was 5 fg l ) and 0.051-0.196 pg l −1 (0.428-1.646 mBq l −1 ), respectively. ᭧

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Recent observations on the physico-chemical speciation of plutonium in the Irish Sea and the western Mediterranean

Cited by 78 publications

References 21 publications

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

Plutonium isotopes as tracers for ocean processes: A review

Determination of plutonium in seawater using co-precipitation and inductively coupled plasma mass spectrometry with ultrasonic nebulisation

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