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INTRODUCTION Since the accidental loss of a nuclear device near Thule, Greenland, in 1968, several scientific expeditions have taken place in the area for the collection of sediment, water and biota samples, and the results were published (1-5). In 1984, the estimated inventories of 239+240p u an d 241 Am in the sediments derived from the accident were 1 TBq and 0.1 TBq respectively (4). Once a chemical species has been incorporated into a sediment, its ultimate fate depends on a number of very complex factors. Some elements can be considered to be irreversibly incorporated into a sedimentary component, whilst others may undergo post-depositional remineralization and take part in various bio-geochemical reactions. In order to predict the fate of transuranics or even make the most primitive evaluations of this kind it is necessary to understand something of the mechanisms by which these elements are incorporated into the various sedimentary phases. It is then not sufficient to carry out chemical analysis on the total samples. The partitioning of transuranics between the various sedimentary components can be studied by physical or chemical separation and subsequent analysis of individual components. The results will depend not only on the nature of the depositional environment but also on the source terms. The chemical and physical partitioning as well as the isotopic composition of the transuranium elements will differ if the source is in form of liquid release from a nuclear fuel reprocessing plant, global fallout from nuclear weapon tests, a nuclear device accident or fallout from a reactor accident such as the recent Chernobyl disaster. This paper presents the chemical partitioning of plutonium and americium between exchangeable, carbonate bound, Fe/Mn oxide bound, organic-sulfide bound and residual fractions in sediments collected in 1968 and 1984 contamined by the accidental loss of a nuclear device. MATERIAL AND METHODS During the expeditions a HAPS corer (6) was used for sediment collection. The sampling area was 145 cm 2 . The cores were cut in 3 cm depth sections to a total depth of 12 cm (or 15 cm when available). Four cores collected close to the point of impact were studied (Table 1). These samples were dried at 100°C, sieved and the fraction <60 pm kept
DOI link for INTRODUCTION Since the accidental loss of a nuclear device near Thule, Greenland, in 1968, several scientific expeditions have taken place in the area for the collection of sediment, water and biota samples, and the results were published (1-5). In 1984, the estimated inventories of 239+240p u an d 241 Am in the sediments derived from the accident were 1 TBq and 0.1 TBq respectively (4). Once a chemical species has been incorporated into a sediment, its ultimate fate depends on a number of very complex factors. Some elements can be considered to be irreversibly incorporated into a sedimentary component, whilst others may undergo post-depositional remineralization and take part in various bio-geochemical reactions. In order to predict the fate of transuranics or even make the most primitive evaluations of this kind it is necessary to understand something of the mechanisms by which these elements are incorporated into the various sedimentary phases. It is then not sufficient to carry out chemical analysis on the total samples. The partitioning of transuranics between the various sedimentary components can be studied by physical or chemical separation and subsequent analysis of individual components. The results will depend not only on the nature of the depositional environment but also on the source terms. The chemical and physical partitioning as well as the isotopic composition of the transuranium elements will differ if the source is in form of liquid release from a nuclear fuel reprocessing plant, global fallout from nuclear weapon tests, a nuclear device accident or fallout from a reactor accident such as the recent Chernobyl disaster. This paper presents the chemical partitioning of plutonium and americium between exchangeable, carbonate bound, Fe/Mn oxide bound, organic-sulfide bound and residual fractions in sediments collected in 1968 and 1984 contamined by the accidental loss of a nuclear device. MATERIAL AND METHODS During the expeditions a HAPS corer (6) was used for sediment collection. The sampling area was 145 cm 2 . The cores were cut in 3 cm depth sections to a total depth of 12 cm (or 15 cm when available). Four cores collected close to the point of impact were studied (Table 1). These samples were dried at 100°C, sieved and the fraction <60 pm kept
INTRODUCTION Since the accidental loss of a nuclear device near Thule, Greenland, in 1968, several scientific expeditions have taken place in the area for the collection of sediment, water and biota samples, and the results were published (1-5). In 1984, the estimated inventories of 239+240p u an d 241 Am in the sediments derived from the accident were 1 TBq and 0.1 TBq respectively (4). Once a chemical species has been incorporated into a sediment, its ultimate fate depends on a number of very complex factors. Some elements can be considered to be irreversibly incorporated into a sedimentary component, whilst others may undergo post-depositional remineralization and take part in various bio-geochemical reactions. In order to predict the fate of transuranics or even make the most primitive evaluations of this kind it is necessary to understand something of the mechanisms by which these elements are incorporated into the various sedimentary phases. It is then not sufficient to carry out chemical analysis on the total samples. The partitioning of transuranics between the various sedimentary components can be studied by physical or chemical separation and subsequent analysis of individual components. The results will depend not only on the nature of the depositional environment but also on the source terms. The chemical and physical partitioning as well as the isotopic composition of the transuranium elements will differ if the source is in form of liquid release from a nuclear fuel reprocessing plant, global fallout from nuclear weapon tests, a nuclear device accident or fallout from a reactor accident such as the recent Chernobyl disaster. This paper presents the chemical partitioning of plutonium and americium between exchangeable, carbonate bound, Fe/Mn oxide bound, organic-sulfide bound and residual fractions in sediments collected in 1968 and 1984 contamined by the accidental loss of a nuclear device. MATERIAL AND METHODS During the expeditions a HAPS corer (6) was used for sediment collection. The sampling area was 145 cm 2 . The cores were cut in 3 cm depth sections to a total depth of 12 cm (or 15 cm when available). Four cores collected close to the point of impact were studied (Table 1). These samples were dried at 100°C, sieved and the fraction <60 pm kept
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