Radioecological risk analysis of ANSTO's monthly effluent releases, 2006-07.

In line with its ISO 14000 initiatives, ANSTO endeavours to identify its environmental impacts. Part of this process includes the assessment of its releases of radioactivity into the wider environment. Liquid effluent with low levels of radioactivity is routinely released via Sydney Water's sewerage system, treated to tertiary standard in the Cronulla Sewage Treatment Plant (CSTP) and finally discharged into the marine environment at Potter Point (Figure 1). These releases occur approximately four times a week and, given the delay and mixing that occurs in transit before discharge into the ocean, can be considered to be a relatively constant release. This raises the question as to whether the releases have the potential to cause unintended environmental impacts in the receiving environment. A comprehensive overview of the potential adverse effects of enhanced environmental radioactivity is given in Copplestone et al. (2001). In this study, the possible radiological dose-rates to biota arising from the radioactivity in the ANSTO effluent have been evaluated and compared to international criteria of acceptability to assess the potential ramifications of release

Accumulation of plutonium in mammalian wildlife tissues: comparison of recent data with the ICRP distribution models

We examined the distribution of plutonium (Pu) in the tissues of mammalian wildlife to address the paucity of such data under environmental exposure conditions. Pu activity concentrations were measured in Macropus rufus (red kangaroo), Oryctolagus cuniculus (European rabbit), and Pseudomys hermannsburgensis (sandy inland mouse)inhabiting the relatively undisturbed, semi-arid conditions at the former Taranaki weapons test site at Maralinga, Australia. Of the absorbed Pu (distributed via circulatory and lymph systems) accumulation was foremost in bone (83% ±10% SD), followed by muscle (9% ±10%), liver (7% ±7%), kidneys (0.5% ±0.3%), and heart (0.4% ±0.4%). The bone values are higher than those reported in ICRP 19 and 48 (45-50% bone), while the liver values are lower than ICRP values (30-45% liver). The ICRP values were based on data dominated by relatively soluble forms of Pu, including prepared solutions and single-atom ions produced by decay following the volatilisation of uranium during nuclear detonation (fallout Pu, ICRP 1986). In contrast, the Maralinga data relates to low-soluble forms of Pu used in tests designed to simulate accidental release and dispersal. We measured Pu in lung, GI-tract and the skin and fur as distinct from the absorbed Pu in bone, liver, muscle, and kidneys. Compared with the mean absorbed activity concentrations, the results for lung tissues were higher by up to one order of magnitude, and those in the GI tract contents and the washed skin/fur were higher by more than two orders of magnitude. These elevated levels are consistent with the presence of low-soluble Pu, including particulate forms, which pass through, or adhere upon, certain organs, but are not readily absorbed into the bloodstream. This more transitory Pu can provide dose to the lung and GI tract organs, as well as provide potential transfer of contamination when consumed in predator-prey food chains, or during human foodstuff consumption. For example, activity concentrations in O. cuniculus edible samples prepared according to traditional aboriginal methods were more than two orders of magnitude higher than in muscle alone. The increase was due to inclusion of GI tract components and contents in the traditional method. Our results provide new insights into the sequestration of Pu in mammalian tissues under environmental exposure conditions. These results contrast with those related to the specific forms of Pu and exposure conditions upon which the ICRP models were based. However, they provide data relevant to the assessment of key environmental legacy waste sites, and of potential release scenarios for the low-soluble oxide forms in the growing worldwide inventory of Pu associated with power production

Analytical method development for tritium in tree transpirate from the little forest burial ground.

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

The Lantern Vol. 15, No. 1, Fall 1946

• Public, Speaking • Concept • The Storm • Yes Sir! • Messengers of Death • The Anonymous Letter • Best Trust the Happy Moments • Disillusionment • The Man With the Water-Brown Eyes • Poetry • Who Knows?https://digitalcommons.ursinus.edu/lantern/1040/thumbnail.jp

Potential use of engineered nanoparticles in ocean fertilization for large-scale atmospheric carbon dioxide removal

Artificial ocean fertilization (AOF) aims to safely stimulate phytoplankton growth in the ocean and enhance carbon sequestration. AOF carbon sequestration efficiency appears lower than natural ocean fertilization processes due mainly to the low bioavailability of added nutrients, along with low export rates of AOF-produced biomass to the deep ocean. Here we explore the potential application of engineered nanoparticles (ENPs) to overcome these issues. Data from 123 studies show that some ENPs may enhance phytoplankton growth at concentrations below those likely to be toxic in marine ecosystems. ENPs may also increase bloom lifetime, boost phytoplankton aggregation and carbon export, and address secondary limiting factors in AOF. Life-cycle assessment and cost analyses suggest that net CO2 capture is possible for iron, SiO2 and Al2O3 ENPs with costs of 2–5 times that of conventional AOF, whereas boosting AOF efficiency by ENPs should substantially enhance net CO2 capture and reduce these costs. Therefore, ENP-based AOF can be an important component of the mitigation strategy to limit global warming

The Lantern Vol. 13, No. 3, June 1945

• Night Shift • To John • The Challenge • My Native Land • Dear to My Heart • Plaint • Peace • Ode to a Soldier • Crossing • Alternative • Mankind\u27s Universal Disease • Chips • No Sensehttps://digitalcommons.ursinus.edu/lantern/1036/thumbnail.jp

Dose modelling comparison for terrestrial biota: IAEA EMRAS II Biota Working Group's Little Forest Burial Ground scenario

Radiological doses to terrestrial biota have been examined in a model inter-comparison study that emphasised the identification of factors causing variability in dose estimation. Radiological dose rates were modelled for ten species representing a diverse range of terrestrial plant and animals with varying behavioural and physical attributes. Dose to these organisms may occur from a range of gamma (Co-60, Cs-137), beta (Sr-90) and alpha (Th-232, U-234 and U-238, Pu-238, Pu-239/240 and Am-241) emitting radionuclides. Whilst the study was based on a specific site - the Little Forest Burial Ground, New South Wales, and Australia - it was intended to be representative of conditions at sites throughout the world where low levels of radionuclides exist in soil due to waste disposal or similar activities

Final report on a field study of soil-to-plant transfer of radioactive caesium, strontium and zinc in tropical Northern Australia to the IAEA/FAO/IUR CRP on classification of soils systems on the basis of transfer factors of radionuclides from soil to reference plants.

Soil-to-plant radionuclide transfer factors for cesium (134Cs), strontium (85Sr) and zinc (65Zn) into sorghum and mung plants grown in tropical Australia have been determined over a four-year study period. The crops were grown on two types of red earth soils. Transfer factors for Cs and Sr are not substantially different from the expected values based on previous studies, reported in the general literature and compiled in the IUR database, mainly performed within temperate climates. In contrast, the values for zinc (Zn) are more than an order of magnitude greater than anticipated. Most of the radioactivity added to the soils has been retained in the top 5 cm of both soils. There has been a general decline in soil-to-plant transfer of Cs and Zn as time has increased

Islands of ice: Influence of free-drifting Antarctic icebergs on pelagic marine ecosystems

Regional warming around West Antarctica, including the Antarctic Peninsula, is related to the retreat of glaciers that has resulted in significant ice mass loss in recent decades. We examined freedrifting icebergs in the Atlantic sector of the Southern Ocean in December 2005, aboard ARSV Laurence M. Gould, and in June 2008 and March/April 2009, aboard RVIB Nathaniel B. Palmer. Prior to these studies, little information was available about the effects of icebergs on the pelagic realm.Facultad de Ciencias Naturales y Muse