Browsing by Author "Andrew, AS"

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    Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS) - discrimination of ammonium nitrate sources
    (Elsevier, 2009-06) Benson, SJ; Lennard, CJ; Maynard, P; Hill, DM; Andrew, AS; Roux, C
    An evaluation was undertaken to determine if isotope ratio mass spectrometry (IRMS) could assist in the investigation of complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques. The focus of the research was on ammonium nitrate (AN), a common oxidiser used in improvised explosive mixtures. The potential value of IRMS to attribute Australian AN samples to the manufacturing source was demonstrated through the development of a preliminary AN classification scheme based on nitrogen isotopes. Although the discrimination utilising nitrogen isotopes alone was limited and only relevant to samples from the three Australian manufacturers during the evaluated time period, the classification scheme has potential as an investigative aid. Combining oxygen and hydrogen stable isotope values permitted the differentiation of AN prills from three different Australian manufacturers. Samples from five different overseas sources could be differentiated utilising a combination of the nitrogen, oxygen and hydrogen isotope values. Limited differentiation between Australian and overseas prills was achieved for the samples analysed. The comparison of nitrogen isotope values from intact AN prill samples with those from post-blast AN prill residues highlighted that the nitrogen isotopic composition of the prills was not maintained post-blast; hence, limiting the technique to analysis of un-reacted explosive material. © 2009, Elsevier Ltd.
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    Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS) - preliminary study on TATP and PETN
    (Elsevier, 2009-06) Benson, SJ; Lennard, CJ; Maynard, P; Hill, DM; Andrew, AS; Roux, C
    The application of isotopic techniques to investigations requiring the provision of evidence to a Court is limited. The objective of this research was to investigate the application of light stable isotopes and isotope ratio mass spectrometry (IRMS) to solve complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques. Due to the current threat of organic peroxide explosives, such as triacetone triperoxide (TATP), research was undertaken to determine the potential of IRMS to differentiate samples of TATP that had been manufactured utilising different starting materials and/or manufacturing processes. In addition, due to the prevalence of pentaerythritoltetranitrate (PETN) in detonators, detonating cord, and boosters, the potential of the IRMS technique to differentiate PETN samples from different sources was also investigated. Carbon isotope values were measured in fourteen TATP samples, with three definite groups appearing in the initial sample set based on the carbon data alone. Four additional TATP samples (in a second set of samples) were distinguishable utilising the carbon and hydrogen isotopic compositions individually, and also in combination with the oxygen isotope values. The 3D plot of the carbon, oxygen and hydrogen data demonstrated the clear discrimination of the four samples of TATP. The carbon and nitrogen isotope values measured from fifteen PETN samples, allowed samples from different sources to be readily discriminated. This paper demonstrates the successful application of IRMS to the analysis of explosives of forensic interest to assist in discriminating samples from different sources. This research represents a preliminary evaluation of the IRMS technique for the measurement of stable isotope values in TATP and PETN samples, and supports the dedication of resources for a full evaluation of this application in order to achieve Court reportable IRMS results. © 2009, Elsevier Ltd.
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    Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)-Part 2: forensic inter-laboratory trial: bulk carbon and nitrogen stable isotopes in a range of chemical compounds (Australia and New Zealand)
    (Wiley-Blackwell, 2010-01) Benson, SJ; Lennard, CJ; Maynard, P; Hill, DM; Andrew, AS; Neal, K; Stuart-Williams, H; Hope, J; Walker, GS; Roux, C
    Comparability of data over time and between laboratories is a key issue for consideration in the development of global databases, and more broadly for quality assurance in general. One mechanism that can be utilized for evaluating traceability is an inter-laboratory trial. This paper addresses an inter-laboratory trial conducted across a number of Australian and New Zealand isotope ratio mass spectrometry (IRMS) laboratories. The main objective of this trial was to determine whether IRMS laboratories in these countries would record comparable values for the distributed samples. Four carbon containing and four nitrogen containing compounds were distributed to seven laboratories in Australia and one in New Zealand. The laboratories were requested to analyze the samples using their standard procedures. The data from each laboratory was evaluated collectively using International Standard ISO 13528 (Statistical methods for use in proficiency testing by inter-laboratory comparisons). "Warning signals" were raised against one participant in this trial. "Action signals" requiring corrective action were raised against four participants. These participants reviewed the data and possible sources for the discrepancies. This inter-laboratory trial was successful in providing an initial snapshot of the potential for traceability between the participating laboratories. The statistical methods described in this article could be used as a model for others needing to evaluate stable isotope results derived from multiple laboratories, e.g., inter-laboratory trials/proficiency testing. Ongoing trials will be conducted to improve traceability across the Australian and New Zealand IRMS community. © 2010, Wiley-Blackwell. The definitive version is available at www3.interscience.wiley.com
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    Geochemical signatures and source material of marine incursion deposits
    (Elsevier, 2016-01-01) Chagué-Goff, C; Andrew, AS; Szczuciński, W; Goff, JR; Nishimura, Y
    The geochemical signature of the Tohoku-oki tsunami deposit and underlying soil was assessed two months, five months and seven months after the 11 March 2011 tsunami inundated the Sendai Plain. The extent of the recognisable sand deposit was traced up to 2.9 km inland while a mud deposit was found up to 4.65 km inland, representing 60% and nearly 95% of the maximum tsunami inundation, respectively. The limit of tsunami inundation was identified 4.85 km from the shore using geochemical marine markers (S and Cl) two months after the tsunami, in the absence of any sedimentological evidence. Concentrations of other geochemical markers (K, Ca, Sr) indicative of the marine incursion and associated minerals were found to decrease landward. δ13C and δ15N and C/N ratios suggested a mixture of terrestrial and marine organic sources in the sediment, while δ34S of sulphate reflected the marine source of water soluble salts. The chemical composition of the 869 AD Jogan tsunami sand deposit was characterised by high Sr and Rb concentrations and was comparable to that of the Tohoku-oki tsunami deposit, suggesting that the sources of sediment may be similar. Marked decreases in S and Cl with time indicated that rainfall resulted in the leaching of salts from the sandy sediments. However, both S and Cl markers as well as Sr were still well preserved in the muddy sediments and underlying soil beyond the limit of the recognisable sand deposit seven months after the tsunami. This suggests that geochemical indicators may well be useful in identifying the extent of historical and palaeotsunamis by determining the marine origin of fine grained sediments beyond the limit of recognisable sand deposition, in particular when marine microfossils are sparse or lacking as is the case on the Sendai Plain. This would allow researchers to redraw palaeotsunami inundation maps and re-assess the magnitude of events such as the Jogan tsunami and other palaeotsunamis, not only on the Sendai Plain but also elsewhere around the world. This has important implications for tsunami risk assessment, hazard mitigation and preparedness.© 2012 Elsevier B.V.
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    Geochemical signatures up to the maximum inundation of the 2011 Tohoku-oki tsunami — Implications for the 869 AD Jogan and other palaeotsunamis
    (Elsevier B.V., 2012-12-30) Chagué-Goff, C; Andrew, AS; Szczuciński, W; Goff, JR; Nishimura, Y
    The geochemical signature of the Tohoku-oki tsunami deposit and underlying soil was assessed two months, five months and seven months after the 11 March 2011 tsunami inundated the Sendai Plain. The extent of the recognisable sand deposit was traced up to 2.9 km inland while a mud deposit was found up to 4.65 km inland, representing 60% and nearly 95% of the maximum tsunami inundation, respectively. The limit of tsunami inundation was identified 4.85 km from the shore using geochemical marine markers (S and Cl) two months after the tsunami, in the absence of any sedimentological evidence. Concentrations of other geochemical markers (K, Ca, Sr) indicative of the marine incursion and associated minerals were found to decrease landward. δ13C and δ15N and C/N ratios suggested a mixture of terrestrial and marine organic sources in the sediment, while δ34S of sulphate reflected the marine source of water soluble salts. The chemical composition of the 869 AD Jogan tsunami sand deposit was characterised by high Sr and Rb concentrations and was comparable to that of the Tohoku-oki tsunami deposit, suggesting that the sources of sediment may be similar. Marked decreases in S and Cl with time indicated that rainfall resulted in the leaching of salts from the sandy sediments. However, both S and Cl markers as well as Sr were still well preserved in the muddy sediments and underlying soil beyond the limit of the recognisable sand deposit seven months after the tsunami. This suggests that geochemical indicators may well be useful in identifying the extent of historical and palaeotsunamis by determining the marine origin of fine grained sediments beyond the limit of recognisable sand deposition, in particular when marine microfossils are sparse or lacking as is the case on the Sendai Plain. This would allow researchers to redraw palaeotsunami inundation maps and re-assess the magnitude of events such as the Jogan tsunami and other palaeotsunamis, not only on the Sendai Plain but also elsewhere around the world. This has important implications for tsunami risk assessment, hazard mitigation and preparedness. © 2020 Elsevier B.V.
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    Insights from stable isotopes for evaluating weed invasion in urban bushland
    (University of New South Wales and Australian Nuclear Science and Technology Organisation, 2015-07-08) Beer, J; Chagué-Goff, C; Andrew, AS; Barry, LA
    Why is Pittosporum undulatum taking over in Sydney’s urban bushland? Bush regeneration manuals recommend removing the native shrub Pittosporum undulatum because it creates shady conditions suppressing regeneration of other native plants. We used stable isotope analysis to compare the water use efciency and nutrient cycling processes of Pittosporum with other plant species to determine why it has a competitive edge in urban bushland. We collected plant, litter and soil samples from eight sites along Wolli Creek in southern Sydney. Four sites were dominated by exotic weeds and Pittosporum undulatum (‘weedy' sites), while the other four sites were dominated by native vegetation species (‘native' sites). Plant, litter and soil samples were analysed for %C, %N, δ13C and δ15N. Plant material and litter at ‘native’ sites had a higher carbon content and lower nitrogen content compared to ‘weedy‘ sites. Soil and Pittosporum undulatum had similar %C and %N values regardless of whether they were collected from ‘native’ or ‘weedy’ sites. Initial results indicate that native species and exotic species had distinct δ13C values in their mature leaf tissue, suggesting higher water use efficiency of native plants. Pittosporum undulatum had a similar isotopic signature to other native species. Nitrogen isotope results show plant species have unique δ15N values reecting unique N capture strategies. Soil δ15N signatures were variable. Pittosporum undulatum was expected to be similar to the exotic plants in terms of isotopic signature, assuming that this native species is utilising resources in a similar way to invasive exotic species. Our pilot study indicates this is not the case, and thus nativespecies may be becoming dominant in urban bushland through other mechanisms. Further research is required to understand how nutrients are captured and cycled in urban bushland.