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Doering C.,Environmental Research Institute of the Supervising Scientist eriss | Saey P.,Vienna University of Technology
Journal of Environmental Radioactivity | Year: 2014

Beryllium-7 (7Be) daily data from the four International Monitoring System (IMS) radionuclide particulate stations on mainland Australia are analysed over the period 2001 to 2011. The analysis indicates that levels of 7Be in surface air at the stations follow annual cycles, with yearly peak activity concentrations occurring later at stations further south. The yearly peak migrates north-south at a rate of approximately 4.4° latitude per month. The change in phase of the 7Be annual cycle between the stations corresponds with the seasonal migration of the Southern Hemisphere Hadley cell across mainland Australia. The implication is that the changing position of the downward limb of the Southern Hemisphere Hadley cell regulates the phase of the annual cycle in 7Be activity concentrations in surface air in the Australian region. © 2013 Elsevier Ltd. Source


Bollhofer A.,Environmental Research Institute of the Supervising Scientist eriss | Doering C.,Environmental Research Institute of the Supervising Scientist eriss
Journal of Environmental Radioactivity | Year: 2016

Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the 222Rn exhalation flux densities normalised to the 226Ra activity concentrations of the substrate. Dry season 222Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season 222Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m-2 s-1 per Bq kg-1) similar to the mixed substrate (0.64 ± 0.08 mBq m-2 s-1 per Bq kg-1), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative 222Rn exhalation and we determined that wet season 222Rn exhalation is about 40% of the dry season exhalation. © 2015. Source


Medley P.,Environmental Research Institute of the Supervising Scientist eriss | Bollhofer A.,Environmental Research Institute of the Supervising Scientist eriss
Journal of Environmental Radioactivity | Year: 2016

In this study, uptake of Ra from soil, and the influence of group II metals on Ra uptake, into the stones and edible flesh of the fruit of the wild green plum, Buchanania obovata, was investigated. Selective extraction of the exchangeable fraction of the soil samples was undertaken but was not shown to more reliably predict Ra uptake than total soil Ra activity concentration. Comparison of the group II metal to Ca ratios (i.e. Sr/Ca, Ba/Ca, Ra/Ca) in the flesh with exchangeable Ca shows that Ca outcompetes group II metals for root uptake and that the uptake pathway discriminated against group II metals relative to ionic radius, with uptake of Ca > Sr > Ba >> Ra. Flesh and stone analysis showed that movement of group II metals to these components of the plant, after root uptake, was strongly related. This supports the hypothesis that Sr, Ba and Ra are being taken up as analogue elements, and follow the same uptake and translocation pathways, with Ca. Comparison with previously reported data from a native passion fruit supports the use of total soil CRs on natural, undisturbed sites. As exchangeable CRs for Ra reach a saturation value it may be possible to make more precise predictions using selective extraction techniques for contaminated or disturbed sites. © 2015. Source


Doering C.,Environmental Research Institute of the Supervising Scientist eriss | Bollhofer A.,Environmental Research Institute of the Supervising Scientist eriss
Journal of Environmental Radioactivity | Year: 2016

A soil guideline value for radiological protection of the environment was determined for the impending rehabilitation of Ranger uranium mine in the wet-dry tropics of northern Australia. The guideline value was 1000 Bq kg-1 of 226Ra in the proposed waste rock substrate of the rehabilitated landform and corresponded to an above-baseline dose rate of 100 μGy h-1 to the most highly exposed individuals of the limiting organism. The limiting organism was reptile based on an assessment using site-specific concentration ratio data. © 2015 Published by Elsevier Ltd. Source


Doering C.,Environmental Research Institute of the Supervising Scientist eriss | Bollhofer A.,Environmental Research Institute of the Supervising Scientist eriss | Bollhofer A.,Federal office for Radiation Protection
Journal of Environmental Radioactivity | Year: 2016

This paper presents a database of radionuclide activity and metal concentrations for the Alligator Rivers Region (ARR) uranium province in the Australian wet-dry tropics. The database contains 5060 sample records and 57,473 concentration values. The data are for animal, plant, soil, sediment and water samples collected by the Environmental Research Institute of the Supervising Scientist (ERISS) as part of its statutory role to undertake research and monitoring into the impacts of uranium mining on the environment of the ARR. Concentration values are provided in the database for 11 radionuclides (227Ac, 40K, 210Pb, 210Po, 226Ra, 228Ra, 228Th, 230Th, 232Th, 234U, 238U) and 26 metals (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, S, Sb, Se, Sr, Th, U, V, Zn). Potential uses of the database are discussed. © 2016 . Source

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