Accumulation of radionuclide and metal contaminants in flesh and osteoderms of estuarine crocodiles (crocodylus porosus): pathways and histories of catchment-specific exposure
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Date
2002-02
Journal Title
Journal ISSN
Volume Title
Publisher
EDP Sciences
Abstract
Flesh and osteoderms of estuarine crocodiles (C. porosus) from Kakadu National Park, Northern Australia, were analysed for a range of metals, including uranium, to assess their capability for accumulation, in relation to their catchment-specific exposure to i) uranium mine effluents and mineralisation and ii) lead shot ammunition through their consumption of fauna shot by the traditional owners of the Park. Uranium in osteoderms was significantly (P<0.05) elevated in the East Alligator River catchment, that contains the Ranger and Jabiluka uranium mine sites, relative to two other adjacent catchments. The mean concentrations of other elements in flesh and osteoderms were also significantly (P<0.05) different between catchments. Linear discriminant analysis was used to demonstrate that multi-element signatures in both flesh and osteoderms could be used to classify individual crocodiles to their respective catchments. This approach may be useful for the identification of source catchments of itinerant 'nuisance crocodiles' that find their way into Darwin Harbour, close to dense human habitation. Lead concentrations were significantly (P<0.05) enhanced in flesh and osteoderms of crocodiles sampled within two areas hunted with guns using Pb ammunition. Enhanced ratios of Pb:Ca in the annual laminations of their osteoderms are consistent with their history of continual exposure to elevated anthropogenic Pb sources. Subsequent experimental studies have demonstrated the ability of the crocodilian stomach to retain ingested Pb shot, that is readily solubilised and absorbed into the blood and then archived in the contemporary osteodermal lamination. © EDP Sciences, 2002
Description
The title of the Conference is shown on the EDP website as: ECORAD 2001: The Radioecology - Ecotoxicology of Continental and Estuatine Environments. This contains a typographical error, the word Estuatine should read Estuarine.
Keywords
Radioisotopes, Heavy metals, Contamination, Reptiles, Estuaries, Northern Territory, Australia, Uranium, Lead
Citation
Jeffree, R. A., Markich, S. J., Hammerton, K., & Russell, R. (2002). Accumulation of radionuclide and metal contaminants in flesh and osteoderms of estuarine crocodiles (crocodylus porosus): pathways and histories of catchment-specific exposure. In F. Bréchignac (Ed.), Radioprotection, 37,(C1), Proceedings of ECORAD 2001: The Radioecology - Ecotoxicology of Continental and Estuatine Environments, Aix-en-Provence, France, 3-7 September, 2001, (pp. C1-853 - C1-857). doi:10.1051/radiopro/2002214