Browsing by Author "Neklapilova, B"

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    Analytical method development for tritium in tree transpirate from the Little Forest Burial Ground
    (Australian Nuclear Science and Technology Organisation, 2009-08) Twining, JR; Harrison, JJ; Vine, M; Creighton, NM; Neklapilova, B; Hoffmann, EL
    The Little Forest Burial Ground (LFBG) is a near-surface low-level nuclear waste repository located within the buffer zone surrounding the Lucas Heights Research Laboratories of ANSTO (Figure 1). Tritium (3H, ‘T’), as tritiated water (HTO), was one of the radioactive substances placed into the trenches located within the LFBG (Isaacs and Mears, 1977). This material will behave conservatively in regard to any seepage from the site of deposition. As such, it should be a good indicator of groundwater movement at the site. Water is a vital requirement of plants. Hence, it was proposed that samples from herbs and trees may be useful to assess the biologically available HTO and also provide an indication of a potential exposure for environmental dose assessment, not only for 3H but also for the other radionuclides potentially migrating with the water from the trenches. As part of the initial draft plan for a vegetation survey in the LFBG (Twining and Creighton, 2007) the following two null hypotheses were established: H0a that there is no significantly higher concentration of specific contaminants in foliage of trees growing over, or adjacent to, the pits than there is in the foliage of the same species growing away from the pits; H0b that there is no correlation between contaminant levels in the seepage plume and surface vegetation. These hypotheses are to be tested using the acquired data. However, as part of the process of applying HTO in transpirate as a monitoring tool, some method development has been required. This report covers all aspects of that development and provides a recommended approach to acquiring such data and recording the information.
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    Application of environmental isotopes to study aquifer interactions and their impact on groundwater salinisation in western Victoria
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2007-11) Raiber, M; Webb, JA; Jacobsen, GE; Chisari, R; Williams, AA; Neklapilova, B
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    Aquifer interactions and their impact on groundwater resources in the Basalt plains of Western Victoria, Australia
    (Taylor and Francis, 2007) Raiber, M; Webb, JA; Jacobsen, GE; Chisari, R; Neklapilova, B
    South of the West Victorian Uplands in southeastern Australia, a series of palaeorivers (so-called "deep leads"), buried beneath 30-120m of basalt, form a complex aquifer system (the Streatham Deep Lead System) which extends over an area of more than 2500 km 2. Groundwater quality both within the unconfined basalt aquifer and the deep lead aquifer ranges from high (suitable for human consumption) to very saline. Combining analyses of several natural environmental isotopes with hydraulic data show that the two aquifers are separated over much of the area. However, preferential recharge to the deep lead system occurs through eruption points, resulting in good quality groundwater in both aquifers in these areas. © 2007 Taylor & Francis Group, London.
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    Method development for tritium measurements and initial evaluation of tritium data for tree transpirate from a legacy waste site in eastern Australia
    (South Pacific Radioactivity Association, 2008-11-25) Twining, JR; Creighton, NM; Harrison, JJ; Hoffmann, EL; Neklapilova, B; Vine, M
    Tritium (3H), as tritiated water, was one of the radioactive substances placed into the trenches located within the former waste disposal site known as the Little Forest Burial Ground (LFBG). This site is located in the 1.6 km exclusion zone surrounding ANSTO the previous research reactor, HIFAR, south of Sydney. Tritium will behave conservatively in regard to any seepage from the site of deposition, and therefore should be a good indicator of groundwater movement at the site. Water is also a vital requirement of plants on the site. Hence, it was proposed that analysis of the tritium content of shrubs and trees may be a useful means to assess and access the biologically available 3H. In addition, it should provide an indication of potential exposure for environmental dose assessment, not only for 3H but also for the other radionuclides potentially migrating with the water from the trenches. To test these ideas, sampling of tree transpirate at LFBG has been initiated. In order to utilise measurements of 3H in transpirate as a monitoring tool, some method development has been required. Relatively small sample volumes have required atypical preparation methods and sample quenching has been an issue. There is also a need to consider background concentrations, given that the HIFAR reactor at the Lucas Heights Research Reactor has emitted 3H to the local environment for several decades. Results of sampling and analysis since July 2007 Will be presented and each of these issues will discussed in this initial report.