The dispersion and fate of the Rhone River inputs to the Gulf of Lions (Northwestern Mediterranean Sea) have been studied through the spatial and temporal distributions of plutonium isotopes in continental shelf sediments. Plutonium isotopes (Pu-238 and Pu-239,Pu-240) are appropriate tracers to follow the dispersion of particulate matter due both to their high affinity for particles and their long half-lives. In the Rhone River valley, plutonium isotopes originate from both the weathering of the catchment basin contaminated by global atmospheric fallout, and the liquid effluents released from the Marcoule reprocessing plant since 1961.This work presents a first detailed study on Pu-238 and Pu-239,Pu-240 distributions in sediments from the Rhone prodelta to the adjacent continental shelf, since the decommissioning of Marcoule in 1997. The vertical distribution of Pu isotopes has been analysed in a 4.75 in long core sampled in 2001 at the Rhone mouth. Despite this length, plutonium is found at the last 10 cm, manifesting the high sedimentation rate of the prodeltaic area and its ability for trapping fine-grained sediments and associated contaminants. The highest Pu-238 and Pu-239,Pu-240 concentrations reached 1.26 and 5.97 Bq kg(-1) respectively and were found within the layer 280-290 cm. The Pu-238/Pu-239,Pu-240 activity ratios (AR) demonstrated an efficient and huge trapping of the Pu isotopes derived from Marcoule. The fresh sediments, located on the top of the core, show lower plutonium activity concentrations and lower Pu-238/Pu-239,Pu-240 ratios. This decrease is in close relation with the shut down of the Marcoule reprocessing plant in 1997.In 2001, plutonium isotopes were also analysed in 21 surface sediments located offshore and concentrations ranged from 0.03 to 0.17 Bq kg(-1) for Pu-238 and from 0.33 to 1.72 Bq kg(-1) for Pu-239,24(0). The Pu-238/Pu-239,Pu-240 AR ranged from 0.24 close to the river mouth to 0.06 southwards, indicating the decreasing influence of the Marcoule releases (global fallout AR 0.03-0.05 and Marcoule AR 0.30). This is in good agreement with the main direction spread of the Rhone River plume and the bottom current. This dataset has been compared to those obtained in the same area in 1984 and 1990 in order to follow the time trend in Pit concentrations. This comparison highlights the decrease with time in plutonium concentrations close to the Rhone River mouth, but further away this reduction is not so evident. (c) 2007 Elsevier B.V. All rights reserved.

A study on the contamination levels and distribution of plutonium in gastropods collected in Palomares (south-east Spain) has been performed. This region is partially contaminated with actinides following the nuclear accident occurred in 1966. The existence of plutonium in gastropods ( Helix albicans and Theba pisana ) along with their great gastronomic interest in the area reinforces the concern in studying the incorporation of these radioelements into a trophic level of the alimentary chain. In this work, plutonium concentration levels have been determined in the excrements, washing waters, flesh and shell of different types of gastropods collected in the Palomares most contaminated area. Plutonium analyses have been carried out following normalized procedures for the determination of this radionuclide. The results show the distribution of plutonium in washing and boiling water, excrements, soft tissues and shell of the snails. In addition, it has been estimated that the consumption of one kilogram of snails collected in the most contaminated area of Palomares could contribute up to 1/3 of the effective dose (due to ingestion) to the inhabitants of the area.

The Palomares terrestrial ecosystem (Spain) constitutes a natural laboratory to study transuranics. This scenario is partially contaminated with weapon-grade plutonium since the burnout and fragmentation of two thermonuclear bombs accidentally dropped in 1966. While performing radiometric measurements in the field, the possible presence of 237Np was observed through its 29 keV gamma emission. To accomplish a detailed characterization of the source term in the contaminated area using the isotopic ratios Pu-Am-Np, the radiochemical isolation and quantification by alpha spectrometry of 237Np was initiated. The selected radiochemical procedure involves separation of Np from Am, U and Pu with ionic resins, given that in soil samples from Palomares 239+240Pu levels are several orders of magnitude higher than 237Np. Then neptunium is isolated using TEVA organic resins. After electrodeposition, quantification is performed by alpha spectrometry. Different tests were done with blank solutions spiked with 236Pu and 237Np, solutions resulting from the total dissolution of radioactive particles and soil samples. Results indicate that the optimal sequential radionuclide separation order is Pu-Np, with decontamination percentages obtained with the ionic resins ranging from 98 % to 100 %. Also, the addition of NaNO2 has proved to be necessary, acting as a stabilizer of Pu-Np valences.

The National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) for seaweed was developed through an interlaboratory comparison with 24 participants from 16 countries. After evaluating different techniques to calculate certified values for the radionuclides, the median method was found to be the most representative technique. The certified values were provided for 13radionuclides and information values were given for 15 more radionuclides. Results for the natural decay series showed disequilibrium in both the uranium and thorium series.

Within an extensive multinational and multidisciplinary project carried out in Dohana National Park (Spain) to investigate its preservation and regeneration, the filling velocity of the salt marshes has been evaluated through the calculation of their average sediment accumulation rates.Pu239+240 and Cs-137 from weapons testing fallout and total Pb-210 distribution profiles and inventories have been determined in some of the most characteristic zones of the park, namely, the ponds 2 (or "lucios") and the waterjets (or "cahos"). Plutonium inventories range from 16 to 101 Bq m(-2), Cs-137 values fluctuate between 514 and 3758 Bq m(-2) and unsupported Pb-210 values comprise between 124 and 9398 Bq m(-2). Average sedimentation rates range from 3 to 5 mm y(-1) (1952-2002). These data are higher than those obtained by carbon dating for the period 6500 AD-present, estimated as 1.5-2 mm y(-1), suggesting an increase in the accumulation of sediments and the alteration of the park's hydrodynamics caused by the re-channeling of the major rivers feeding the salt marshes. (c) 2006 Elsevier Ltd. All rights reserved.

The salt marsh of the Donana National Park are one of the most important wet zones in the world. During the last fifty years it has shown a great degradation, due to the intense sedimentation rates. This degradation has influenced in the transformation of its ecological characteristics. In the present work this sedimentation is analyzed, comparing the stages of its Holocene evolution (last 6000 years) with present periods: last five decades (1952-2002) and last four years (2000-2004). The study compares the natural and antropics sedimentation rates; a considerable increase at recent times has been observed. The causes are attributed to the alteration of their hydrologic dynamics, mainly as a result of the channelling and rectifications of the Guadiamar and Guadalquivir rivers. The plans of regeneration elaborated by the Central Administration, trying to palliate this problem, are analyzed.

Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their affinity to associate with the downward falling particulate matter, more abundant at shallower depths. In this paper, the distribution profiles and inventories of plutonium, americium and cesium are detailed, providing useful information about recent sedimentation phenomena such as sediment mixing, slumping processes and bioturbation. Unsupported 210Pb data are used as reliable indicators of enhanced/reduced deposition events. Also, the calculated inventories have enabled the estimation of the radiological contribution of the Spanish Mediterranean margin to the total radioactivity deposited onto the Mediterranean sea floor.

The Aquatic Radioactivity Laboratory of Ciemat has been performing transuranic analyses in different types of matrices such as soils, marine sediments and biota for a good number of years. Analysing americium in large size/volume samples by employing ionic-exchange resins becomes a long and tedious process, usually resulting in low chemical recoveries. A new procedure to isolate americium from environmental samples has been developed by concentrating americium in a Diphonix resin. This resin is then destroyed by calcination at 550°C and further digestion with HNO3 and H2O2 in a microwave oven programmed with increasing pressure stages, reaching 175 psi. Isolation is completed with TRU-Spec and TEVA-Spec columns. Americum is finally quantified by high resolution alpha spectrometry. Analyses carried out with various reference IAEA materials proved that this new method produces higher radiochemical yields, thus allowing treatment of smaller environmental samples.

The activity concentrations and fluxes of natural (Pb-210, Po-210) and anthropogenic (Pu-239,Pu-240 Cs-137) radionuclides have been determined in the different water masses crossing the Strait of Gibraltar. New data have been gathered during four multidisciplinary and multinational sampling campaigns, performed between 1997 and 1999 within the framework of the CANIGO-FLUGIST Project.Mean activity concentrations of Po-210 (1.53 +/- 0.34 Bq m(-3), n = 30) and Pb-210 (1.16 +/- 0.50 Bq m(-3), n = 31) in the Atlantic water entering the Mediterranean basin are about double those measured in the Mediterranean outflow, namely 0.84 +/- 0.34 Bq m(-3) (n = 22) for Po-210 and 0.66 +/- 0.34 Bq m(-3) (n = 22) for Pb-210. The opposite trend is observed for Pu-239,Pu-240 with average concentrations of 9.9 +/- 3.0 mBq m(-3) (n = 29) in the incoming Atlantic flow and 22.0 +/- 3.0 mBq m(-3) (n = 22) in the outpouring Mediterranean water. In the case of Cs-137, the same concentrations were quantified in the waters moving inwards (2.52 +/- 0.28 Bq m(-3), n = 27) and outwards (2.14 +/- 0.52 Bq m(-3), n = 21) from the Mediterranean Sea.On this basis, the Mediterranean basin experiences a net annual input flux of 14 TBq of Pb-210 and 19 TBq of Po-210, and a net annual loss of 0.34 TBq of Pu-239,Pu-240, while-at present-Cs-137 input and output fluxes appear to be balanced. (C) 2002 Elsevier Science Ltd. All rights reserved.

Plutonium isotopic ratios have been calculated in soils contaminated by the Palomares accident which occurred in 1966 (Almería, Southeastem Spain). Contrasted techniques have been used to determine the radionuclide activities:238Pu and238+240Pu were analysed by α-spectrometry prior purification on anion-exchange resins, the ratio239Pu/240Pu was estimated by α-spectra deconvolution and241Pu was directly measured by liquid scintillation counting and indirectly through quantification of in-grown241Am from aged plutonium discs. The mean activity ratios238Pu/239Pu,239Pu/240Pu,241Pu/239Pu, backdated to 1966, were 0.027±0.002 (1σ), 4.5±0.2 (1σ) and 8.2±0.8 (1σ), respectively, characterizing the accident of Palomares as the source term of the measured plutonium.

To trace the consequences of the Palomares accident which occurred in southeastern Spain in 1966, a number of studies were performed upon sediments collected in the adjacent marine ecosystem in 1985. The research revealed a land-to-sea transport of part of the transuranics residual contamination still remaining in the affected area after the clean-up operations. The transfer routes to the Mediterranean sea (via river flooding and airborne relocation) were elucidated through the reconstruction of the sediment cores' depositional history. Present investigations focus on the distribution of Pu, Am and Cs along the complex system of submarine canyons shaping the orography of the Palomares marine environment. Marine samples were collected in 1991 to evaluate the possible removal of the radionuclides deposited in the continental shelf towards the deep sea, favoured by the strong turbidity currents and/or the topography of the canyon itself.

Journal Article Man-Made Radioactivity in the Almanzora Gulch and Beach Edge of Palomares, Spain Get access C. Gascó, C. Gascó Search for other works by this author on: Oxford Academic PubMed Google Scholar M.P. Antón, M.P. Antón Search for other works by this author on: Oxford Academic PubMed Google Scholar P. Rivas P. Rivas Search for other works by this author on: Oxford Academic PubMed Google Scholar Radiation Protection Dosimetry, Volume 58, Issue 4, 1 March 1995, Pages 301–306, https://doi.org/10.1093/oxfordjournals.rpd.a082629 Published: 01 March 1995

The geochemical association of plutonium in sediments from the marine ecosystem of Palomares has been studied. A sequential leaching technique using selective extractants has been employed to determine the percentages of Pu in the following forms: (a) readily available, (b) exchangeable and adsorbed to specific sites, (c) associated with organic matter, (d) sesquioxides, (e) residual. Plutonium was found to be associated mainly with phases (c), (d) and (e), and therefore, appears to be relatively inmobile and not readily available to bottom feeding biota. The effect of different source terms on Pu distribution is also discussed.

Activity concentrations of 241Pu and other transuranics were determined in different fractions (water soluble, readily available or physically bound, carbonate bound or specifically adsorbed, bound to organic matter, bound to Fe and Mn sesquioxides, and residual) of mud taken from a radioactive waste storage deposit and from solid residue accumulated in a pipe of the liquid effluent system. Two sets of extractants were used at the Department of Radiochemistry and Colloid Chem- istry of Maria Curie Sklodowska University (UMCS) and CIEMAT laboratories, along with different procedures concerning reagent concentrations, shaking time, temperature, and order of reagent extraction. 241Pu measurements in the fractions were performed directly by liquid scintillation counting (LSC) and indirectly via alpha spectrometry by quantifying 241Am ingrowth from old Pu discs. In addition to these investigations, alpha-emitting plutonium and americium isotopes were also determined and compared. The results show that direct measurement of beta-emitting plutonium via LSC yields more accu- rate results than indirect calculation via its descendant, 241Am. The distribution percentages of transuranics bound to the extracted fractions are presented, indicating that iron and manganese oxides are the most important phases for Pu fixation. The influence of the extraction procedure employed on radionuclide distribution among the different fractions is also dis- cussed.