Browsing by Author "Harrison, JJ"
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- ItemAccumulation of plutonium in mammalian wildlife tissues following dispersal by accidental-release tests(Elsevier, 2016-01-01) Johansen, MP; Child, DP; Caffrey, EA; Harrison, JJ; Hotchkis, MAC; Payne, TE; Ikeda-Ohno, A; Thiruvoth, S; Beresford, NA; Twining, JR; Davis, EWe examined the distribution of plutonium (Pu) in the tissues of mammalian wildlife inhabiting the relatively undisturbed, semi-arid former Taranaki weapons test site, Maralinga, Australia. The accumulation of absorbed Pu was highest in the skeleton (83% ± 6%), followed by muscle (10% ± 9%), liver (6% ± 6%), kidneys (0.6% ± 0.4%), and blood (0.2%). Pu activity concentrations in lung tissues were elevated relative to the body average. Foetal transfer was higher in the wildlife data than in previous laboratory studies. The amount of Pu in the gastrointestinal tract was highly elevated relative to that absorbed within the body, potentially increasing transfer of Pu to wildlife and human consumers that may ingest gastrointestinal tract organs. The Pu distribution in the Maralinga mammalian wildlife generally aligns with previous studies related to environmental exposure (e.g. Pu in humans from worldwide fallout), but contrasts with the partitioning models that have traditionally been used for human worker-protection purposes (approximately equal deposition in bone and liver) which appear to under-predict the skeletal accumulation in environmental exposure conditions. © 2015, Elsevier Ltd.
- ItemAnalytical 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, ELThe 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.
- ItemAnthropogenic acceleration of sediment accretion in lowland floodplain wetlands, Murray–Darling Basin, Australia(Elsevier, 2009-07-01) Gell, PA; Fluin, J; Tibby, J; Hancock, G; Harrison, JJ; Zawadzki, A; Haynes, D; Khanum, SI; Little, F; Walsh, BOver the last decade there has been a deliberate focus on the application of paleolimnological research to address issues of sediment flux and water quality change in the wetlands of the Murray–Darling Basin of Australia. This paper reports on the research outcomes on cores collected from sixteen wetlands along the Murrumbidgee–Murray River continuum. In all sixteen wetlands radiometric techniques and exotic pollen biomarkers were used to establish sedimentation rates from the collected cores. Fossil diatom assemblages were used to identify water source and quality changes to the wetlands. The sedimentation rates of all wetlands accelerated after European settlement, as little as two-fold, and as much as eighty times the mean rate through the Late Holocene. Some wetlands completely infilled through the Holocene, while others have rapidly progressed towards a terrestrial state due to accelerated accretion rates. Increasing wetland salinity and turbidity commenced within decades of settlement, contributing to sediment inputs. The sedimentation rate was observed to slow after river regulation in one wetland, but has accelerated recently in others. The complex history of flooding and drying, and wetland salinisation and eutrophication, influence the reliability of models used to establish recent, fine-resolution chronologies with confidence and the capacity to attribute causes to documented effects. © 2009 Elsevier B.V
- ItemThe application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)(Springer Nature, 2018-02-06) Kristo, MJ; Williams, R; Gaffney, AM; Kayzar-Boggs, TM; Schorzman, KC; Lagerkvist, P; Vesterlund, A; Ramebäck, H; Nelwamondo, AN; Kotze, D; Song, K; Lim, SH; Han, SH; Lee, CG; Okubo, A; Maloubier, D; Cardona, D; Samuleev, P; Dimayuga, I; Varga, Z; Wallenius, M; Mayer, K; Loi, E; Keegan, EA; Harrison, JJ; Thiruvoth, S; Stanley, FE; Spencer, KJ; Tandon, LIn a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the 235U–231Pa and 234U–230Th chronometers confirmed the validity of the age dating assumptions, increasing confidence in the resulting conclusions. © 2018 U.S. Government
- ItemAssessing soil remobilisation in catchments using a 137Cs-sediment hillslope model(Taylor & Francis (Routledge), 2008-12) Simms, AD; Woodroffe, CD; Jones, BG; Heijnis, H; Harrison, JJ; Mann, RASoil redistribution studies are important, especially in water supply catchments, because the rate at which denudation is occurring has implications for offsite water quality. However, the extent to which soil is redistributed within the landscape can be difficult to determine. This challenge can be overcome using fallout caesium-137 (137Cs). This paper describes the rates of soil loss and remobilisation in two sub-catchments within the Sydney Basin region, namely Kembla and Kentish Creeks, which drain to the Cordeaux reservoir. The total inventories of 137Cs in catchment soils were determined, a 137Cs-regression equation and a theoretical diffusion and migration model were used to established relationships between 137Cs inventories and the rates of soil loss. These relationships revealed relatively low occurrence of soil loss in Kentish Creek, but two slopes in the Kembla Creek sub-catchment had losses that appear to be moderate. However, there was no clear evidence to suggest whether slopes in upper and lower reaches of catchments had specific patterns of soil remobilisation. Qualitative categorisation of the slope elements using a 137Cs-sediment hillslope model can be a useful sentinel for land users and decision makers even if absolute rates of soil loss or gain are not certain. The findings suggest that sediments mobilised in the study sub-catchments are not likely to impact significantly on the water quality in the Cordeaux reservoir. © 2008, Taylor & Francis (Routledge).
- ItemAssessment of radionuclide distributions at an Australian legacy radioactive waste site(South Pacific Radioactivity Association, 2010-09-01) Payne, TE; Cendón, DI; Collins, RN; Dore, M; Hankin, SI; Harrison, JJ; Hughes, CE; Johansen, MP; Thiruvoth, S; Twining, JR; Wilsher, KLDuring the 1960s, low level radioactive waste was buried in shallow trenches at a disposal site in south-eastern Australia, known as the Little Forest Burial Ground. This paper discusses preliminary findings of research into the distribution of radionuclides at the site, including soils, groundwater and biota. In particular, we are studying the mobility of radionuclides; and their uptake by plants, insects and small animals. Groundwater monitoring indicates that there has been limited movement of radioactivity, other than a tritium plume that extends at least 100 m. The tritium results are being used to define the groundwater flowpaths, and the effects of seasonal and climatic factors. The pattern of tritium distribution suggests that the source of tritium is predominantly within the waste materials. However, tritium derived from a nearby municipal landfill contributes to tritium concentrations in some groundwaters, with smaller amounts from cosmogenic tritium and atmospheric deposition originating from the nearby HIFAR reactor (shut down in 2007). The tritium data provide a record of water movement against which the relative mobility of other radionuclides can be assessed. There are measurable amounts of 60Co, 90Sr, 137Cs and traces of actinides in some soils, groundwater and vegetation samples taken in close proximity to the disposal area. Isotopic ratios such as δ13C, δ180, δ2H, δ34S and 87Sr/86Sr are being measured in groundwater, in addition to the radioactive isotopes originating from the disposed wastes. Synchrotron EXAFS and XANES studies are being applied to study elemental chemical environments and oxidation states in the soils at the site. We have recently undertaken a major geophysical investigation and drilling program; and installation of an improved array of water sampling boreholes is planned. Therefore, many more samples of groundwater and soils are becoming available for analysis.
- ItemAssessment of radionuclide movement at an Australian legacy radioactive waste site(EMSL, 2009-09-20) Payne, TE; Cendón, DI; Collins, RN; Hankin, SI; Harrison, JJ; Hughes, CE; Johansen, MP; Twining, JR; Waite, TDNot available
- ItemBiotic, temporal and spatial variability of tritium concentrations in transpirate samples collected in the vicinity of a near-surface low-level nuclear waste disposal site and nearby research reactor(Elsevier Science Ltd, 2011-06-01) Twining, JR; Hughes, CE; Harrison, JJ; Hankin, SI; Crawford, J; Johansen, MP; Dyer, LLThe results of a 21 month sampling program measuring tritium in tree transpirate with respect to local sources are reported. The aim was to assess the potential of tree transpirate to indicate the presence of sub-surface seepage plumes. Transpirate gathered from trees near low-level nuclear waste disposal trenches contained activity concentrations of (3)H that were significantly higher (up to similar to 700 Bq L(-1)) than local background levels (0-10 Bq L(-1)). The effects of the waste source declined rapidly with distance to be at background levels within 10s of metres. A research reactor 1.6 km south of the site contributed significant (p < 0.01) local fallout (3)H but its influence did not reach as far as the disposal trenches. The elevated (3)H levels in transpirate were, however, substantially lower than groundwater concentrations measured across the site (ranging from 0 to 91% with a median of 2%). Temporal patterns of tree transpirate (3)H, together with local meteorological observations, indicate that soil water within the active root zones comprised a mixture of seepage and rainfall infiltration. The degree of mixing was variable given that the soil water activity concentrations were heterogeneous at a scale equivalent to the effective rooting volume of the trees. In addition, water taken up by roots was not well mixed within the trees. Based on correlation modelling, net rainfall less evaporation (a surrogate for infiltration) over a period of from 2 to 3 weeks prior to sampling seems to be the optimum predictor of transpirate (3)H variability for any sampled tree at this site. The results demonstrate successful use of (3)H in transpirate from trees to indicate the presence and general extent of sub-surface contamination at a low-level nuclear waste site. Crown Copyright © 2011, Elsevier Ltd.
- ItemCapability development for the quantification of Ba-133 in milk powder by gamma-ray spectrometry(South Pacific Environmental Radioactivity Association, 2018-11-06) Van De Voorde, R; Mokhber-Shahin, L; Harrison, JJ; van Wyngaardt, WM; Jackson, TWBarium-133 (Ba-133) is a fission product with a half-life of 10.5 years. It decays to its daughter radionuclide Cs-183 by electron capture, emitting multiple characteristic gamma emissions. The capability to accurately quantify Ba-133 is of importance due to its persistence in the environment. This is enabled by its relatively long half-life and its uptake into the food chain due to its similarity in chemical properties to calcium. Therefore, screening for contamination of calcium-rich foodstuffs such as milk and milk powders, is required following a nuclear or radioactive contamination event. Refining a capability to quantify Ba-138 utilising gamma-ray spectrometry is advantageous due to its requirement of minimal sample preparation and usefulness in screening for a wide range of other radionuclides, therefore providing critical information in a relatively timely manner. in the 2017 IAEA ALMERA proficiency test exercise ANSTO’s Radioanalytical Chemistry Capability group demonstrated its proficiency in quantifying Ba-138 in water, and in quantifying other nuclides such as Cs-187 and Sr-90 in milk powder. However, the activity concentration of Ba-188 in the milk powder matrix was lower than the target value. Therefore, a study was undertaken to optimise a method for accurately quantifying Ba-138 in milk powder by gamma-ray spectrometry, holistically investigating the entire process from sample receipt and storage to counting geometry and interpretation of data. A series of storage and drying experiments were undertaken to optimise a method for determining the moisture content of a variety of supermarket bought milk powders, comparing measured mass changes using both desiccator and benchtop cooling following oven-drying. The impact of storage following unsealing the received sample container on moisture content was investigated and its implications on subsequent internal and cross-laboratory analysis were explored. The milk powders were packed into various geometries and analysed by gamma-ray spectrometry to quantify the naturally-occurring radionuclides present in the milk powder. This data was used to better understand the matrix and investigate the possible interference of naturally-occurring radionuclides in the quantification of Ba-188. Milk powders were also purposefully spiked with known activities of Ba-133 and a comparison of various counting geometries, the impact of sample density and self-absorption on counting efficiency were investigated. The use of a variety of calibration standards of varying geometries and densities was also explored to assess their applicability to the milk powder matrix. This paper will detail the investigation findings and propose recommendations for a more reliable method for the quantification of Ba-133 in milk powder by gamma-ray spectrometry to be hence employed in ANSTO’s Radioanalytical Chemistry Capability laboratory.
- ItemChallenges in the radiochemical separation of marine samples from the Montebello Islands(South Pacific Environmental Radioactivity Association, 2018-11-06) Thiruvoth, S; Child, DP; Harrison, JJ; Johansen, MP; Silitonga, A; Vardanega, CR; Wilsher, KL; Wong, HKYThe Montebello Islands, located off the North Western coast of Western Australia, was used as a nuclear weapons test site by the British government in the 1950s. Three nuclear tests were conducted around the islands. The first in 1952 (W818) detonated in the hull of the HMS Plym anchored in 12 m of water between Alpha and Trimouille Islands, and the second and third tests (MOSAIC G1 and G2) were detonated on 30 m Aluminium towers in May and June 1956, G1 on the Northern Western tip of Trimouille island and G2, the largest test conducted in Australian territory, on Alpha island. The fallout from these tests deposited long-lived anthropogenic radionuclides on nearby islands and ocean surface, host to an array of animals and plants. Marine sand, marine sediment, algae, fish, turtles and turtle eggs, among others, were sampled from the surrounding zones for dose assessment studies, thirty-nine of which were processed for actinide and strontium analysis. Due to the expected presence of discrete radioactive particles in some matrices a three step digestion method was applied to obtain complete dissolution of sample material. To overcome sample heterogeneity, the digest solution was sub-sampled for actinide and Sr-90 analysis by alpha spectrometry and liquid scintillation analysis, for plutonium isotopic analysis by AMS, and for elemental analysis by ICPAES/MS. The radiochemical separation method developed at ANSTO for Am, Pu, Th, U, and Sr for terrestrial soils and sediments (Harrison et al, 2011) was adapted to samples from the marine environment. However, some sample matrices proved to be challenging in achieving acceptable chemical recoveries of strontium due to the high concentrations of native calcium. This current study will discuss the methods used, and challenges overcome, in radiochemical separation for alpha spectrometry and liquid scintillation analysis for a wide range of sample types.
- ItemChanging fluxes of sediments and salts as recorded in lower River Murray wetlands, Australia(International Association of Hydrological Sciences (IAHS), 2006-07-06) Gell, PA; Fluin, J; Tibby, J; Haynes, D; Khanum, SI; Walsh, B; Hancock, G; Harrison, JJ; Zawadzki, A; Little, FThe River Murray basin, Australia’s largest, has been significantly impacted by changed flow regimes and increased fluxes of salts and sediments since settlement in the 1840s. The river’s flood plain hosts an array of cut-off meanders, levee lakes and basin depression lakes that archive historical changes. Pre-European sedimentation rates are typically approx. 0.1–1 mm year-1, while those in the period after European arrival are typically 10 to 30 fold greater. This increased sedimentation corresponds to a shift in wetland trophic state from submerged macrophytes in clear waters to phytoplankton dominated, turbid systems. There is evidence for a decline in sedimentation in some natural wetlands after river regulation from the 1920s, but with the maintenance of the phytoplankton state. Fossil diatom assemblages reveal that, while some wetlands had saline episodes before settlement, others became saline after, and as early as the 1880s. The oxidation of sulphurous salts deposited after regulation has induced hyperacidity in a number of wetlands in recent years. While these wetlands are rightly perceived as being heavily impacted, other, once open water systems, that have infilled and now support rich macrophyte beds, are used as interpretive sites. The rate of filling, however, suggests that the lifespan of these wetlands is short. The rate of wetland loss through such increased infilling is unlikely to be matched by future scouring as regulation has eliminated middle order floods from the lower catchment. © 2006 IAHS Press
- ItemComparison of radium-228 determination in water among Australian laboratories(Elsevier, 2017-11) Zawadzki, A; Cook, M; Cutmore, B; Evans, F; Fierro, D; Gedz, A; Harrison, JJ; Loosz, T; Medley, P; Mokhber-Shahin, L; Mullins, S; Sdraulig, SThe National Health and Medical Research Council and Natural Resource Management Ministerial Council of Australia developed the current Australian Drinking Water Guidelines which recommend an annual radiation dose value of 1 mSv year−1. One of the potential major contributors to the radiation dose from drinking water is radium-228, a naturally occurring radionuclide arising from the thorium decay series. Various methods of analysing for radium-228 in water have been established and adapted by analytical radiochemistry laboratories. Seven laboratories in Australia participated in analysing radium-228 spiked water samples with activity concentrations ranging from 6 mBq L−1 to 20 Bq L−1. The aim of the exercise was to compare and evaluate radium-228 results reported by the participating laboratories, the methods used and the detection limits. This paper presents the outcome of the exercise. Crown Copyright © 2017 Published by Elsevier Ltd.
- ItemCyst and radionuclide evidence demonstrate historic Gymnodinium catenatum dinoflagellate populations in Manukau and Hokianga Harbours, New Zealand(Elsevier, 2003-03) Irwin, A; Hallegraeff, GM; McMinn, A; Harrison, JJ; Heijnis, HBetween May 2000 and February 2001, a major bloom of the toxic dinoflagellate Gymnodinium catenatum (a causative organism of Paralytic Shellfish Poisoning, PSP) affected over 1500 km of coastline of New Zealand’s North Island. As this was the first record of this species in New Zealand, we aimed to resolve whether this represented a recent introduction/spreading event or perhaps an indigenous cryptic species stimulated by environmental/climatic change. To answer this question, we analysed for G. catenatum resting cysts in 210Pb dated sediment cores (18–34 cm long; sedimentation rates 0.34–0.69 cm per year) collected by SCUBA divers from Manukau Harbour, where the species was first detected, and from Hokianga Harbour, where the highest shellfish toxicity was recorded, while using Wellington Harbour as a well-monitored control site. The results of this study conclusively demonstrate that abundant G. catenatum has been in northern New Zealand at least since the early 1980s, increasing up to 1200 cysts/g around the year 2000, but with low cyst concentrations possibly present since at least 1937. In contrast, Wellington Harbour cores contained only very sparse G. catenatum cysts (8 cysts/g), present only to a depth of 7 cm (surface mixed layer depth), reflecting an apparent recent range expansion of this dinoflagellate in New Zealand, possibly stimulated by unusual climatic conditions associated with the 2000 La Nina event. The significant increases since the early 1980s also of Protoperidinium cysts at Hokianga Harbour and of Gonyaulax, Protoperidinium and Protoceratium cysts at Manukau Harbour suggest a broad scale environmental change has occurred in Northland, New Zealand. © 2003 Elsevier Science B.V
- ItemDetermining the history and sources of contaminants in sediments in the Tamar Estuary, Tasmania, using 210Pb dating and stable Pb isotope analyses(CSIRO Publishing, 2004-06-30) Seen, A; Townsend, AT; Atkinson, B; Ellison, J; Harrison, JJ; Heijnis, H210Pb dating and heavy metal analyses (Cd, Cu, Pb, Zn) have been combined to establish an historical profile of pollutant levels in sediments in the Tamar Estuary (Tasmania, Australia) over the past century. Heavy metal profiles through the core show a strong correlation with mining activities and industrialization during the past century, reflecting catchment disturbance in one of Australia’s earliest settled areas. A source apportionment of Pb in the sediment core using stable Pb isotope ratios (204Pb, 206Pb, 207Pb, 208Pb) shows that mine pollution has been contributing 10–25 mg kg–1 to Tamar Estuary sediments since the start of mining in the early 1890s, whilst non-mining inputs were not significant until post-1930 and became increasingly significant post-World War II. Since the 1950s–1960s, non-mining anthropogenic Pb inputs have become as significant as Pb from mining activities, although there does appear to be a decline in non-mining inputs during the past 20 years, which is consistent with findings elsewhere where reductions in atmospheric Pb levels have been observed and are attributed to the phasing-out of leaded gasoline. The source apportionment does, however, suggest that Pb from mine pollution at Storys and Aberfoyle Creeks continues to impact upon upper Tamar Estuary sediment quality. © CSIRO 2004
- ItemEcosystem impacts of feral rabbits on World Heritage sub-Antarctic Macquarie Island: a palaeoecological perspective(Elsevier, 2013-11) Saunders, KM; Harrison, JJ; Hodgson, DA; de Jong, R; Mauchle, F; McMinn, AThe introduction and establishment of non-indigenous species through human activities often poses a major threat to natural biodiversity. In many parts of the world management efforts are therefore focused on their eradication. The environment of World Heritage sub-Antarctic Macquarie Island has been severely damaged by non-indigenous species including rabbits, rats and mice, introduced from the late AD 1800s. An extensive eradication programme is now underway which aims to remove all rabbits and rodents. To provide a long-term context for assessing the Island's pre-invasion state, invasion impacts, and to provide a baseline for monitoring its recovery, we undertook a palaeoecological study using proxies in a lake sediment core. Sedimentological and diatom analyses revealed an unproductive catchment and lake environment persisted for ca. 7100 years prior to the introduction of the invasive species. After ca. AD 1898, unprecedented and statistically significant environmental changes occurred. Lake sediment accumulation rates increased >100 times due to enhanced catchment inputs and within-lake production. Total carbon and total nitrogen contents of the sediments increased by a factor of four. The diatom flora became dominated by two previously rare species. The results strongly suggest a causal link between the anthropogenic introduction of rabbits and the changes identified in the lake sediments. This study provides an example of how palaeoecology may be used to determine baseline conditions prior to the introduction of non-indigenous species, quantify the timing and extent of changes, and help monitor the recovery of the ecosystem and natural biodiversity following successful non-indigenous species eradication programmes. © 2014 Elsevier Ltd.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2004-2005(Australian Nuclear Science and Technology Organisation, 2005-11) Hoffmann, EL; Loosz, T; Ferris, JM; Harrison, JJThis report presents the results of ANSTO's environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2004 to June 2005. Effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less than 0.005 mSv/year. This estimated maximum potential dose is less than 24% of the ANSTO ALARA objective of 0.02 mSv/year, and much lower than the public dose limit of 1 mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). The effective doses to the critical group of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The levels of tritium detected in groundwater and stormwater at the LHSTC were less than those set out in the Australian Drinking Water Guidelines. The airborne and liquid effluent emissions from the NMC were below both the ARPANSA-approved notification levels and Sydney Water limits for acceptance of trade wastewater to sewer. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. ANSTO's routine operations at the LHSTC and NMC make only a very small addition to the natural background radiation dose of ~1.5 mSv/year experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites, 2005-2006(Australian Nuclear Science and Technology Organisation, 2007-03) Hoffmann, EL; Loosz, T; Ferris, JM; Harrison, JJThis report presents the results of ANSTO's environmental and effluent monitoring at Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2005 to June 2006. Estimated effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less that 0.005 mSv/year. The maximum potential dose was 23% of the ANSTO ALARA objective of 0.02 mSv/year, much lower than the public dose limit of 1mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Authority (ARPANSA). The effective doses to the critical groups of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The medium tritium concentrations detected in groundwater and surface waters at the LHSTC were typically less than 2% of those set out in the Australian Drinking Water Guidelines. The airborne emissions from the NMC were below the ARPANSA-approved notification levels. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. ANSTO's routine operations at the LHSTC and NMC make only a very small addition to the natural background radiation dose of ~1.5 mSv/year experienced by members of the Australian public.
- ItemEnvironmental and effluent monitoring at ANSTO sites: 2003-2004(Australian Nuclear Science and Technology Organisation, 2004-10) Hoffmann, EL; Ferris, JM; Harrison, JJ; Loosz, TThis report presents the results of ANSTO's environmental and effluent monitoring at the Lucas Heights Science and Technology Centre (LHSTC) and the National Medical Cyclotron (NMC) sites, from July 2003 to June 2004. Effective doses to the critical group of members of the public potentially affected by routine airborne emissions from the LHSTC were less than 0.004 mSv/year. This estimated maximum potential dose is less than 20% of the ANSTO ALARA objective of 0.02 mSv/year and much lower than the public dose limit of 1 mSv/year that is recommended by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). The effective doses to the critical group of members of the public potentially exposed to routine liquid effluent releases from the LHSTC have been realistically estimated as a quarter (or less) of the estimated doses to the critical group for airborne releases. The levels of tritium detected in groundwater and stormwater at the LHSTC were less than the Australian Drinking Water Guidelines. The airborne and liquid effluent emissions from the NMC were below the ARPANSA-approved notification levels and NSW Department of Environment and Conservation limits, respectively. Results of environmental monitoring at both ANSTO sites confirm that the facilities continue to be operated well within regulatory limits. Members of the public are exposed to only very small doses of radiation from ANSTO's routine airborne and liquid effluent releases.
- ItemEnvironmental isotopes to study radionuclide migration mechanisms at the Little Forest legacy site(University of New South Wales and Australian Nuclear Science and Technology Organisation, 2015-07-10) Hughes, CE; Cendón, DI; Harrison, JJ; Johansen, MP; Payne, TENot provided to ANSTO Library.
- ItemEnvironmental mobility of cobalt-influence of solid phase characteristics and groundwater chemistry.(Elsevier Ltd, 2008-05) Payne, TE; Itakura, T; Comarmond, MJ; Harrison, JJThe adsorption of cobalt on samples from a potential waste repository site in an arid region was investigated in batch experiments, as a function of various solution phase parameters including the pH and ionic strength. The samples were characterized using a range of techniques, including BET surface area measurements, total clay content and quantitative X-ray diffraction. The statistical relationships between the measured cobalt distribution coefficients (Kd values) and the solid and liquid phase characteristics were assessed. The sorption of cobalt increased with the pH of the aqueous phase. In experiments with a fixed pH value, the measured Kd values were strongly correlated to the BET surface area, but not to the amount of individual clay minerals (illite, kaolinite or smectite). A further set of sorption experiments was undertaken with two samples of distinctive mineralogy and surface area, and consequently different sorption properties. A simple surface complexation model (SCM) that conceptualized the surface sites as having equivalent sorption properties to amorphous Fe-oxide was moderately successful in explaining the pH dependence of the sorption data on these samples. Two different methods of quantifying the input parameters for the SCM were assessed. While a full SCM for cobalt sorption on these complex environmental substrates is not yet possible, the basic applicability and predictive capability of this type of modeling is demonstrated. A principal requirement to further develop the modeling approach is adequate models for cobalt sorption on component mineral phases of complex environmental sorbents. © 2009, Elsevier Ltd.