U, Pu, and Am nuclear signatures of the Thule hydrogen bomb debris.

This study concerns an arctic marine environment that was contaminated by actinide elements after a nuclear accident in 1968, the so-called Thule accident In this study we have analyzed five isolated hot particles as well as sediment samples containing particles from the weapon material for the determination of the nuclear fingerprint of the accident. We report that the fissile material in the hydrogen weapons involved in the Thule accident was a mixture of highly enriched uranium and weapon-grade plutonium and that the main fissile material was 235U (about 4 times more than the mass of 239Pu). In the five hot particles examined, the measured uranium atomic ratio was 235U/238U = 1.

Characterization of the NIST seaweed Standard Reference Material.

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 13 radionuclides and information values were given for 15 more radionuclides.

Studies of Np and Pu in the marine environment of Swedish-Danish waters and the North Atlantic Ocean.

The long-lived anthropogenic radionuclides (237)Np, (239)Pu and (240)Pu were determined in marine environmental samples (seaweed and seawater) collected from Swedish-Danish waters and the North Atlantic Ocean at various locations on different occasions during the period 1991-2001. The measurements were performed with sector field Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and conventional alpha spectrometry. The (237)Np activity concentrations in Fucus vesiculosus and surface seawater from the Swedish west coast and Danish waters ranged from 0.

Characterization of uranium and plutonium containing particles originating from the nuclear weapons accident in Thule, Greenland, 1968.

To improve long-term radioecological impact assessment for the contaminated ecosystem of Bylot Sound, Greenland, U and Pu containing particles have been characterized with respect to particle size, elemental distribution, morphology and oxidation states. Based on scanning electron microscopy with XRMA, particles ranging from about 20 to 40 microm were isolated. XRMA and mu-XRF mapping demonstrated that U and Pu were homogeneously distributed throughout the particles, indicating that U and Pu have been fused.

Levels and trends of radioactive contaminants in the Greenland environment.

Levels of radioactive contaminants in various Greenland environments have been assessed during 1999-2001. The source of 137Cs, 90Sr and (239,240)Pu in terrestrial and fresh water environments is mainly global fallout. In addition, the Chernobyl accident gave a small contribution of 137Cs.

Distribution and flux of 238Pu, 239,240Pu, 241Am, 137Cs and 210Pb to high arctic lakes in the Thule district (Greenland).

Environmental samples (soil, sediment and lake water) in the Thule area (NW Greenland) have been studied to assess the contamination of radionuclides originating from a nuclear weapons accident (the Thule accident in 1968). Four lakes were chosen at different distances from the point of impact with the Thule air base community situated in between. The sedimentation rates in the lakes varied from 0.

Level and origin of iodine-129 in the Baltic Sea.

Environmental samples, such as seawater, seaweed, lake water, lake sediment and grass collected from the Baltic Sea area were analyzed for 129I and 127I by radiochemical neutron activation analysis. In 2000, the concentration of 129I in the seawater from Borholm and Møen in the Baltic Sea has reached 6.0 x 10(-13) and 16 x 10(-13) g/l, respectively, these are more than two orders of magnitude higher than the global fallout level.

Iodine-129 and caesium-137 in Chernobyl contaminated soil and their chemical fractionation.

Soil samples from areas in Belarus, Russia and Sweden contaminated by the Chernobyl accident were analysed for (129)I by radiochemical neutron activation analysis, as well as for 137Cs by gamma-spectrometry. The atomic ratio of (129)I/137Cs in the upper layer of the examined soil cores ranged from 0.10 to 0.

Iodine-129 in thyroid and urine in Ukraine and Denmark.

Human thyroids collected from Gomel in Belarus, sheep thyroid from Jutland and human urine from Zealand in Denmark were analysed for 129I and 127I concentrations. The ratios of 129I/127I in human thyroid in Gomel are 2.65-11.

Comparison of two ICP-MS set-ups for measuring 99Tc in large volume water samples.

Large volume fjord and seawater samples have been radiochemically prepared for ICP-MS analysis in order to test the robustness of the procedure and to carry out a comparison of two ICP-MS set-ups. A sector field instrument (MicroMass PT2) coupled with an ultrasonic nebuliser and a quadrupole ICP-MS (Perkin-Elmer Elan 6000) coupled with an electrothermal vaporisation (ETV) unit were used. The results showed that the radiochemical procedure was robust, removing Ru and Mo to acceptable levels, and that the two set-ups gave results that were in agreement.

Process-diagnostic patterns of chlorobiphenyl congeners in two radiochronologically characterized sediment cores from the northern Baffin Bay.

Polychlorinated biphenyl (PCB) patterns were interpreted in two radioisotopically constrained sediment cores from the Arctic ocean in order to seek clues about their large-scale environmental fates. Low but clearly measurable fluxes of individual PCB congeners were observed in deeper layer sediments, corresponding to the past 170 years, in a single dated core from the Baffin Bay shelf. Fluxes of the dominant individual congeners in the surface sediments were 20-100 pg m(-2) d(-1).

Oxidation-state distribution of plutonium in surface and subsurface waters at Thule, northwest Greenland.

The speciation of plutonium in Arctic waters sampled on the northwest Greenland shelf in August 1997 is discussed in this paper. Specifically, we report the results of analyses carried out on seawater sampled (a) close to the Thule air base where, in 1968, a US military aircraft carrying four nuclear weapons crashed on sea ice, releasing kilogram quantities of plutonium to the snow pack and underlying seabed sediments, and (b) at a reference station (Upernavik) located approximately 400 km to the south. The data show that most of the plutonium in the dissolved phase at Thule is in the form of Pu(V, VI) (mean: 68+/-6%; n = 6), with little if any distinction apparent between surface and bottom waters.

Iodine-129 in human thyroids and seaweed in China.

The concentrations of 129I and the ratios of 129I/127I in normal human thyroids collected in Tianjin, China, and some seaweed samples from the Chinese coast were determined by neutron activation analysis. The mean 129I/127I ratio in these thyroids was found to be 1.13 x 10(-9), which is two orders of magnitude higher than the level of the pre-nuclear era, but one order of magnitude lower than the level in Europe in the post-nuclear era.

Environmental radioactive contamination in Greenland: a 35 years retrospect.

Environmental studies of anthropogenic radionuclides in Greenland over four decades are reported. The studies have comprised the marine as well as the terrestrial environments and emphasis has been laid on measurements of 90Sr and 137Cs. The temporal and the spatial trends of these radionuclides are described.

Marine radioactivity assessment of Mururoa and Fangataufa atolls.

The International Atomic Energy Agency (IAEA) carried out an international project. 'The Study of the Radiological Situation at the Atolls of Mururoa and Fangataufa' with the aim of assessing the present and future radiological situation at the atolls and making recommendations for either monitoring or remedial actions if they are deemed necessary. The paper concentrates on marine radioactivity aspects and gives an estimation of present radionuclide concentrations in water, sediment and biota of the Mururoa and Fangataufa lagoons and the surrounding ocean.

Marine radioactivity in the Arctic: a retrospect of environmental studies in Greenland waters with emphasis on transport of 90Sr and 137Cs with the East Greenland Current.

The waters around Greenland have received radioactive contamination from three major sources: Global fallout, discharges from the nuclear fuel reprocessing plant Sellafield in the UK, and the Chernobyl accident in the Former Soviet Union (FSU). The global fallout peaked in the early 1960s. The radiologically most important radionuclides from this source are 90Sr and 137Cs.

Perturbation in the 240Pu/239Pu global fallout ratio in local sediments following the nuclear accidents at Thule (Greenland) and Palomares (Spain).

It is well established that the main source of the plutonium found in marine sediments throughout the Northern Hemisphere is global stratospheric fallout, characterized by a typical 240Pu/239Pu atom ratio of approximately 0.18. Measurement of perturbations in this ratio at various sites which had been subjected to close-in fallout, mainly from surface-based testing (e.

Further studies of plutonium and americium at Thule, Greenland.

Eleven years after the accidental loss of nuclear weapons in 1968, the fourth scientific expedition to Thule occurred. The estimated inventory of 1 TBq 239,240Pu in the marine sediments was unchanged when compared with the estimate based on the 1974 data. Plutonium from the accident had moved further away from the impact point and at some locations the vertical distribution indicated a downward displacement of Pu in the sediment column since 1974.