Plutonium transfer to wildlife at legacy sites

When internalized within an organism’s body, plutonium (Pu) can be important in dose calculation due to its relatively high-energy alpha emissions (~5-6 MeV). In this paper we quantify transfer of Pu to a range of wildlife types at legacy nuclear weapons sites and evaluate the importance of body tissue Pu distribution in the transfer of Pu through the food chain. The paper presents new data from Maralinga, Australia, as well as past data from terrestrial and marine settings of the US nuclear research program

Uranium sorption on various forms of Ti02 - influence of surface area, surface charge and impurities.

Titanium dioxide has properties that make it an excellent substrate for experimental study and theoretical development of adsorption models, including negligible solubility and a near neutral point of zero charge 1. A number of different forms of Ti-oxide have been used in experimental studies, including hydrous Ti-oxide, anatase, rutile and various commercially available samples that contain a mixture of anatase and rutile. The aim of our work is to investigate uranium sorption phenomena and the influence of surface area, surface charge and impurities for a range of thoroughly characterised Ti-oxide surfaces. We have undertaken uranium(VI) sorption studies on a number of commercially available Ti oxides, some of which were aggressively pre-treated to remove inherent impurities. Characterisations performed on the various Ti-oxides comprised a range of chemical and physical methods including XRD, XRF, ATR FT-IR, chemical assays, BET determinations, and electroacoustic measurements. The sorption of U on these Ti oxides was studied by a baTch sorption method and the effect of pH, ionic strength, mass loading, and U concentration on uranium sorption was also investigated for several of these Tioxides. We found that the sorption of uranium (VI) on these Tioxides was extremely strong and much greater than many other common environmental sorbents on a surface area basis. Aggressive pre-treatment of one Ti-oxide significantly altered its isoelectric point, but did not appear to significantly impact its sorption behaviour. Differences in sorption behaviour between the various Ti-oxides were related to the surface area of these materials. The data provide insights into the effect of different source materials and surface properties on radionuclide sorption, and will be useful in assessing data obtained in diverse experimental studies involving Ti oxides

Measurement of 233U/234U ratios in contaminated groundwater using alpha spectrometry.

The uranium isotope 233U is not usually observed in alpha spectra from environmental samples due to its low natural and fallout abundance. It may be present in samples from sites in the vicinity of nuclear operations such as reactors or fuel reprocessing facilities, radioactive waste disposal sites or sites affected by clandestine nuclear operations. On an alpha spectrum, the two most abundant alpha emissions of 233U (4.784 MeV, 13.2%; and 4.824 MeV, 84.3%) will overlap with the 234U doublet peak (4.722 MeV, 28.4%; and 4.775 MeV, 71.4%), if present, resulting in a combined 233+234U multiplet. A technique for quantifying both 233U and 234U from alpha spectra was investigated. A series of groundwater samples were measured both by accelerator mass spectrometry (AMS) to determine 233U/234U atom and activity ratios and by alpha spectrometry in order to establish a reliable 233U estimation technique using alpha spectra. The Genie™ 2000 Alpha Analysis and Interactive Peak Fitting (IPF) software packages were used and it was found that IPF with identification of three peaks (234U minor, combined 234U major and 233U minor, and 233U major) followed by interference correction on the combined peak and a weighted average activity calculation gave satisfactory agreement with the AMS data across the 233U/234U activity ratio range (0.1–20) and 233U activity range (2–300 mBq) investigated. Correlation between the AMS 233U and alpha spectrometry 233U was r2 = 0.996 (n = 10). © 2015, Elsevier Ltd

Solution speciation of plutonium and Americium at an Australian legacy radioactive waste disposal site

During the 1960s, radioactive waste containing small amounts of plutonium (Pu) and americium (Am) was disposed in shallow trenches at the Little Forest Burial Ground (LFBG), located near the southern suburbs of Sydney, Australia. Because of periodic saturation and overflowing of the former disposal trenches, Pu and Am have been transferred from the buried wastes into the surrounding surface soils. The presence of readily detected amounts of Pu and Am in the trench waters provides a unique opportunity to study their aqueous speciation under environmentally relevant conditions. This study aims to comprehensively investigate the chemical speciation of Pu and Am in the trench water by combining fluoride coprecipitation, solvent extraction, particle size fractionation, and thermochemical modeling. The predominant oxidation states of dissolved Pu and Am species were found to be Pu(IV) and Am(III), and large proportions of both actinides (Pu, 97.7%; Am, 86.8%) were associated with mobile colloids in the submicron size range. On the basis of this information, possible management options are assessed. © 2014, American Chemical Society

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site.

Radioactive waste containing a few grams of plutonium (Pu) was disposed between 1960 and 1968 in trenches at the Little Forest Burial Ground (LFBG), near Sydney, Australia. A water sampling point installed in a former trench has enabled the radionuclide content of trench water and the response of the water level to rainfall to be studied. The trench water contains readily measurable Pu activity (similar to 12 Bq/L of Pu239+240 in 0.45 mu m-filtered water), and there is an associated contamination of Pu in surface soils. The highest Pu239+240 soil activity was 829 Bq/kg in a shallow sample (0-1 cm depth) near the trench sampling point. Away from the trenches, the elevated concentrations of Pu in surface soils extend for tens of meters down-slope. The broader contamination may be partly attributable to dispersion events in the first decade after disposal, after which a layer of soil was added above the trenched area. Since this time, further Pu contamination has occurred near the trench-sampler within this added layer. The water level in the trench-sampler responds quickly to rainfall and intermittently reaches the surface, hence the Pu dispersion is attributed to saturation and overflow of the trenches during extreme rainfall events, referred to as the 'bathtub' effect.© 2013, American Chemical Society

Uranium sorption on various forms fo titanium dioxide - influence of surface area, surface charge and impurities

Titanium dioxide (TiO(2)) has often served as a model substrate for experimental sorption studies of environmental contaminants. However, various forms of Ti-oxide have been used, and the different sorption properties of these materials have not been thoroughly studied. We investigated uranium sorption on some thoroughly characterized TiO(2) surfaces with particular attention to the influence of surface area, surface charge, and impurities. The sorption of U(VI) differed significantly between samples. Aggressive pretreatment of one material to remove impurities significantly altered the isoelectric point, determined by an electroacoustic method, but did not significantly impact U sorption. Differences in sorption properties between the various TiO(2) materials were related to the crystallographic form, morphology, surface area, and grain size, rather than to surface impurities or surface charge. In-situ attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectroscopic studies showed that the spectra of the surface species of the TiO(2) samples are not significantly different, suggesting the formation of similar surface complexes. The data provide insights into the effect of different source materials and surface properties on radionuclide sorption. © 2011, American Chemical Societ

Proposal of a new classification scheme for periocular injuries

Background: Eyelids are important structures and play a role in protecting the globe from trauma, brightness, in maintaining the integrity of tear films and moving the tears towards the lacrimal drainage system and contribute to aesthetic appearance of the face. Ophthalmic trauma is an important cause of morbidity among individuals and has also been responsible for additional cost of healthcare. Periocular trauma involving eyelids and adjacent structures has been found to have increased recently probably due to increased pace of life and increased dependence on machinery. A comprehensive classification of periocular trauma would help in stratifying these injuries as well as study outcomes. Material and Methods: This study was carried out at our institute from June 2015 to Dec 2015. We searched multiple English language databases for existing classification systems for periocular trauma. We designed a system of classification of periocular soft tissue injuries based on clinico-anatomical presentations. This classification was applied prospectively to patients presenting with periocular soft tissue injuries to our department. Results: A comprehensive classification scheme was designed consisting of five types of periocular injuries. A total of 38 eyelid injuries in 34 patients were evaluated in this study. According to the System for Peri-Ocular Trauma (SPOT) classification, Type V injuries were most common. SPOT Type II injuries were more common isolated injuries among all zones. Discussion: Classification systems are necessary in order to provide a framework in which to scientifically study the etiology, pathogenesis, and treatment of diseases in an orderly fashion. The SPOT classification has taken into account the periocular soft tissue injuries i.e., upper eyelid, lower eyelid, medial and lateral canthus injuries., based on observed clinico-anatomical patterns of eyelid injuries. Conclusion: The SPOT classification seems to be a reliable system to address eyelid injuries. This classification scheme would guide the ophthalmic and facial reconstructive surgeons to provide optimal outcomes in eyelid injuries. Based on the classification scheme and review of existing literature, an algorithm is presented to facilitate repair and reconstruction

Plutonium in wildlife and soils at the Maralinga legacy site : Persistence over decadal time scales

The mobility of plutonium (Pu) in soils, and its uptake into a range of wildlife, were examined using recent and ~25 year old data from the Taranaki area of the former Maralinga weapons test site, Australia. Since its initial deposition in the early 1960s, the dispersed Pu has been incorporated into the soil profile and food chain through natural processes, allowing for the study of Pu sequestration and dynamics in relatively undisturbed semi-arid conditions.The data indicate downward mobility of Pu in soil at rates of ~0.2-0.3cm per year for the most mobile fraction. As a result, while all of the Pu was initially deposited on the ground surface, approximately 93% and 62% remained in the top 0-2cm depth after 25- and 50-years respectively. No large-scale lateral spreading of the Taranaki plume was observed. Pu activity concentrations in 0-1cm soils with biotic crusts were not elevated when compared with nearby bare soils, although a small number of individual data suggest retention of Pu-containing particles may be occurring in some biotic crusts. Soil-to-animal transfer, as measured by concentration ratios (CRwo-soil), was 4.1E-04 (Geometric Mean (GM)) in mammals, which aligns well with those from similar species and conditions (such as the Nevada Test Site, US), but are lower than the GM of the international mammal data reported in the Wildlife Transfer Database (WTD). These lower values are likely due to the presence of a low-soluble, particulate form of the Pu in Maralinga soils. Arthropod concentration ratios (3.1E-03 GM), were similar to those from Rocky Flats, US, while values for reptiles (2.0E-02 GM) were higher than the WTD GM value which was dominated by data from Chernobyl. Comparison of uptake data spanning approximately 30 years indicates no decrease over time for mammals, and a potential increase for reptiles. The results confirm the persistence of bioavailable Pu after more than 50 years since deposition, and also the presence of larger-sized particles which currently affect CRwo-soil calculations, and which may serve as an ongoing source of bioavailable Pu as they are subjected to weathering into the future

Plutonium uptake in biota at former nuclear sites

Plutonium (Pu) is of ongoing interest as worldwide inventories continue to increase and plans for permanent storage of Pu wastes have stalled in many countries leaving large amounts in temporary storage. Pu also remains as environmental contamination at various locations due to: accidents (e.g., Chernobyl, UKR; Thule, GRL); research and processing releases (e.g., Los Alamos, USA, Mayak, RUS); and former weapons testing (e.g., Nevada Test Site, USA; Semipalatinsk, KAZ; and Maralinga, AUS). We assessed the availability and uptake of Pu in a range of wildlife types at legacy sites with the focus on new data from outside of the remediation zone at the former Taranaki site, Maralinga, South Australia. Of key interest are the uptake and biokinetics of Pu in mammals, particularly from environmental exposure to the undetonated Pu-oxide forms at Taranaki that are representative of much of the worldwide inventory. Our results confirm that environmentally dispersed Pu can remain accessible for uptake by biota over decadal time scales. For example, after more than 50 years since deposition at Taranaki, 62% of Pu has remained in the 0-2 cm surface layer, and nearly 100% in the 0-10 cm of soil depths. Although a small fraction of the Pu is migrating downward at —0.2 cm per year, it appears that most Pu will continue to remain accessible into the future for plants and animals that inhabit the surface, or shallow soil layers. The uptake of Pu into terrestrial animals occurs mainly by inhalation and ingestion, and can be persistent over time as indicated by constant uptake rates for mammals, and a potential increase for reptiles, in data spanning 30 years. The rates of soil-to-animal transfer at Taranaki, align well with those from similar sites where undetonated Pu was tested (e.g., Nevada Test Site, US). However, the uptake values at these sites are lower than general world-wide values, likely due to the presence of less-absorbable forms of Pu. The importance of the physico-chemical form of the Pu on uptake was also seen in data from fish exposed to more absorbable forms of Pu in liquid discharge ponds near processing facilities in the US. These fish had two orders of magnitude higher uptake values than those for similar species receiving Pu solely from atmospheric fallout. The physico-chemical form of the Pu can also influence how it is distributed among mammalian organs. The relatively insoluble forms at Taranaki, which include particulates, led to elevated concentrations of unabsorbed Pu in the lung, gastrointestinal tract, and adhered to skin/fur of mammals. This elevated Pu can provide a secondary source during human, and ecological, food-chain consumption. Of the Pu that was absorbed within the body, much higher accumulation was measured in the skeleton, and much lower in the liver, in mammals at Taranaki as compared with the standard model of 50% skeleton, and 30% liver (ICRP 1986). Our data provides specific quantification of Pu uptake rates in wildlife and the subsequent accumulation in various mammalian organs. These will aid future assessments of the Maralinga site, as well as more general evaluations related to the low-solubility forms of Pu that make up a large share of the worldwide inventory

Camphor burns of the palm and non-suicidal self-injury: An uncommonly reported, but socially relevant issue

Camphor is a waxy white sublimating chemical derived from natural as well as synthetic sources and widely used in various communities worldwide for a number of medicinal, culinary, and religious reasons. Camphor is burnt as an offering to God in many religious communities. We report three incidences of self inflicted injury from burning camphor on the palm resulting in full thickness burns. Non-suicidal self-injury is socially unacceptable destruction or alteration of body tissue when there is no suicidal intent or pervasive developmental disorder and we have explored an association between this and burn injury. This report also highlights the unique social and cultural pattern of this burn injury and the importance of psycho-therapeautic help for these victims