Plutonium uptake in wildlife at Maralinga, South Australia

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Australian Nuclear Science and Technology Organisation
This study examined accumulation of plutonium (Pu) in wildlife at Maralinga, South Australia, where a 1950s series of experiments dispersed unfissioned Pu onto the landscape. The residual Pu concentrations that remain today are lower than the site clean-up level, but are sufficient to provide a rare opportunity to study wildlife organisms that have been exposed to a food web and soils containing elevated Pu. Analysis was by gamma- and alpha- spectroscopy, and by accelerator mass spectrometry at ANSTO. Uptake of Pu was quantified by concentration ratios, defined as average concentration in the whole-organism, to that of their host soil (CRwo-soil). The geometric mean of CRwo-soil values for all organisms was 0.002 (geometric standard deviation – 4.1E00) with mammals<insects<arthropods<reptiles. Within rabbit, activity concentrations of various tissue types ranged from 1.6 to 1700 mBq/kg (with muscle<blood<bone<liver<heart-lung<gastrointestinal tract<skin-fur). The contents within the gastrointestinal tract of rabbit had order-of-magnitude higher Pu concentrations than all organs and tissues indicating most of the ingested Pu is not being absorbed across the intestinal wall. The elevated concentration of Pu in the lung compartment is indicative of an inhalation pathway. Our results add to international data on transfer of Pu to living organisms, and better define accumulation in specific tissues of various organism types within a Pucontaminated natural system. © The Authors.
Plutonium, Wild animals, Nuclear test sites, South Australia, Australia, Cleaning, Decontamination, Food, Soils, Rabbits
Johansen, M. P., Child, D. P., Collins, R. N., Davis, E., Doering, C., Harrison, J. J., Hotchkis, M. A. C., Payne, T. E., Mokhber-Shahin, L., Ryan, B., Thiruvoth, S., Twining, J. R., Wilsher, K., & Wood, M. D. (2012). Plutonium uptake in wildlife at Maralinga, South Australia. Paper presented to the 12th South Pacific Environmental Radioactivity Association Conference (SPERA 2012), Tuesday 16 October – Friday 19 October 2012 Sydney, Australia. Lucas Heights, NSW: Australian Nuclear Science and Technology Organisation, (pp. 28).